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You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA Also add information on how to contact you by electronic and paper mail. You should also get your employer (if you work as a programmer) or your school, if any, to sign a "copyright disclaimer" for the library, if necessary. Here is a sample; alter the names: Yoyodyne, Inc., hereby disclaims all copyright interest in the library `Frob' (a library for tweaking knobs) written by James Random Hacker. , 1 April 1990 Ty Coon, President of Vice That's all there is to it! udns-0.6/udns.h0000644000175000017500000006516314650630470011640 0ustar mjtmjt/* udns.h header file for the UDNS library. Copyright (C) 2005 Michael Tokarev This file is part of UDNS library, an async DNS stub resolver. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library, in file named COPYING.LGPL; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #ifndef UDNS_VERSION /* include guard */ #define UDNS_VERSION "0.6" #ifdef WINDOWS # ifdef UDNS_DYNAMIC_LIBRARY # ifdef DNS_LIBRARY_BUILD # define UDNS_API __declspec(dllexport) # define UDNS_DATA_API __declspec(dllexport) # else # define UDNS_API __declspec(dllimport) # define UDNS_DATA_API __declspec(dllimport) # endif # endif #endif #ifndef UDNS_API # define UDNS_API #endif #ifndef UDNS_DATA_API # define UDNS_DATA_API #endif #include /* for time_t */ #ifdef __cplusplus extern "C" { #endif /* forward declarations if sockets stuff isn't #include'd */ struct in_addr; struct in6_addr; struct sockaddr; /**************************************************************************/ /**************** Common definitions **************************************/ UDNS_API const char * dns_version(void); struct dns_ctx; struct dns_query; /* shorthand for [const] unsigned char */ typedef unsigned char dnsc_t; typedef const unsigned char dnscc_t; #define DNS_MAXDN 255 /* max DN length */ #define DNS_DNPAD 1 /* padding for DN buffers */ #define DNS_MAXLABEL 63 /* max DN label length */ #define DNS_MAXNAME 1024 /* max asciiz domain name length */ #define DNS_HSIZE 12 /* DNS packet header size */ #define DNS_PORT 53 /* default domain port */ #define DNS_MAXSERV 6 /* max servers to consult */ #define DNS_MAXPACKET 512 /* max traditional-DNS UDP packet size */ #define DNS_EDNS0PACKET 4096 /* EDNS0 packet size to use */ enum dns_class { /* DNS RR Classes */ DNS_C_INVALID = 0, /* invalid class */ DNS_C_IN = 1, /* Internet */ DNS_C_CH = 3, /* CHAOS */ DNS_C_HS = 4, /* HESIOD */ DNS_C_ANY = 255 /* wildcard */ }; enum dns_type { /* DNS RR Types */ DNS_T_INVALID = 0, /* Cookie. */ DNS_T_A = 1, /* Host address. */ DNS_T_NS = 2, /* Authoritative server. */ DNS_T_MD = 3, /* Mail destination. */ DNS_T_MF = 4, /* Mail forwarder. */ DNS_T_CNAME = 5, /* Canonical name. */ DNS_T_SOA = 6, /* Start of authority zone. */ DNS_T_MB = 7, /* Mailbox domain name. */ DNS_T_MG = 8, /* Mail group member. */ DNS_T_MR = 9, /* Mail rename name. */ DNS_T_NULL = 10, /* Null resource record. */ DNS_T_WKS = 11, /* Well known service. */ DNS_T_PTR = 12, /* Domain name pointer. */ DNS_T_HINFO = 13, /* Host information. */ DNS_T_MINFO = 14, /* Mailbox information. */ DNS_T_MX = 15, /* Mail routing information. */ DNS_T_TXT = 16, /* Text strings. */ DNS_T_RP = 17, /* Responsible person. */ DNS_T_AFSDB = 18, /* AFS cell database. */ DNS_T_X25 = 19, /* X_25 calling address. */ DNS_T_ISDN = 20, /* ISDN calling address. */ DNS_T_RT = 21, /* Router. */ DNS_T_NSAP = 22, /* NSAP address. */ DNS_T_NSAP_PTR = 23, /* Reverse NSAP lookup (deprecated). */ DNS_T_SIG = 24, /* Security signature. */ DNS_T_KEY = 25, /* Security key. */ DNS_T_PX = 26, /* X.400 mail mapping. */ DNS_T_GPOS = 27, /* Geographical position (withdrawn). */ DNS_T_AAAA = 28, /* Ip6 Address. */ DNS_T_LOC = 29, /* Location Information. */ DNS_T_NXT = 30, /* Next domain (security). */ DNS_T_EID = 31, /* Endpoint identifier. */ DNS_T_NIMLOC = 32, /* Nimrod Locator. */ DNS_T_SRV = 33, /* Server Selection. */ DNS_T_ATMA = 34, /* ATM Address */ DNS_T_NAPTR = 35, /* Naming Authority PoinTeR */ DNS_T_KX = 36, /* Key Exchange */ DNS_T_CERT = 37, /* Certification record */ DNS_T_A6 = 38, /* IPv6 address (deprecates AAAA) */ DNS_T_DNAME = 39, /* Non-terminal DNAME (for IPv6) */ DNS_T_SINK = 40, /* Kitchen sink (experimentatl) */ DNS_T_OPT = 41, /* EDNS0 option (meta-RR) */ DNS_T_DS = 43, /* DNSSEC */ DNS_T_SSHFP = 44, DNS_T_IPSECKEY = 45, DNS_T_RRSIG = 46, /* DNSSEC */ DNS_T_NSEC = 47, /* DNSSEC */ DNS_T_DNSKEY = 48, DNS_T_DHCID = 49, DNS_T_NSEC3 = 50, DNS_T_NSEC3PARAMS = 51, DNS_T_TALINK = 58, /* draft-ietf-dnsop-trust-history */ DNS_T_SPF = 99, DNS_T_UINFO = 100, DNS_T_UID = 101, DNS_T_GID = 102, DNS_T_UNSPEC = 103, DNS_T_TSIG = 250, /* Transaction signature. */ DNS_T_IXFR = 251, /* Incremental zone transfer. */ DNS_T_AXFR = 252, /* Transfer zone of authority. */ DNS_T_MAILB = 253, /* Transfer mailbox records. */ DNS_T_MAILA = 254, /* Transfer mail agent records. */ DNS_T_ANY = 255, /* Wildcard match. */ DNS_T_ZXFR = 256, /* BIND-specific, nonstandard. */ DNS_T_DLV = 32769, /* RFC 4431, 5074, DNSSEC Lookaside Validation */ DNS_T_MAX = 65536 }; /**************************************************************************/ /**************** Domain Names (DNs) **************************************/ /* return length of the DN */ UDNS_API unsigned dns_dnlen(dnscc_t *dn); /* return #of labels in a DN */ UDNS_API unsigned dns_dnlabels(dnscc_t *dn); /* lower- and uppercase single DN char */ #define DNS_DNLC(c) ((c) >= 'A' && (c) <= 'Z' ? (c) - 'A' + 'a' : (c)) #define DNS_DNUC(c) ((c) >= 'a' && (c) <= 'z' ? (c) - 'a' + 'A' : (c)) /* compare the DNs, return dnlen of equal or 0 if not */ UDNS_API unsigned dns_dnequal(dnscc_t *dn1, dnscc_t *dn2); /* copy one DN to another, size checking */ UDNS_API unsigned dns_dntodn(dnscc_t *sdn, dnsc_t *ddn, unsigned ddnsiz); /* convert asciiz string of length namelen (0 to use strlen) to DN */ UDNS_API int dns_ptodn(const char *name, unsigned namelen, dnsc_t *dn, unsigned dnsiz, int *isabs); /* simpler form of dns_ptodn() */ #define dns_sptodn(name,dn,dnsiz) dns_ptodn((name),0,(dn),(dnsiz),0) UDNS_DATA_API extern dnscc_t dns_inaddr_arpa_dn[14]; #define DNS_A4RSIZE 30 UDNS_API int dns_a4todn(const struct in_addr *addr, dnscc_t *tdn, dnsc_t *dn, unsigned dnsiz); UDNS_API int dns_a4ptodn(const struct in_addr *addr, const char *tname, dnsc_t *dn, unsigned dnsiz); UDNS_API dnsc_t * dns_a4todn_(const struct in_addr *addr, dnsc_t *dn, dnsc_t *dne); UDNS_DATA_API extern dnscc_t dns_ip6_arpa_dn[10]; #define DNS_A6RSIZE 74 UDNS_API int dns_a6todn(const struct in6_addr *addr, dnscc_t *tdn, dnsc_t *dn, unsigned dnsiz); UDNS_API int dns_a6ptodn(const struct in6_addr *addr, const char *tname, dnsc_t *dn, unsigned dnsiz); UDNS_API dnsc_t * dns_a6todn_(const struct in6_addr *addr, dnsc_t *dn, dnsc_t *dne); /* convert DN into asciiz string */ UDNS_API int dns_dntop(dnscc_t *dn, char *name, unsigned namesiz); /* convert DN into asciiz string, using static buffer (NOT thread-safe!) */ UDNS_API const char * dns_dntosp(dnscc_t *dn); /* return buffer size (incl. null byte) required for asciiz form of a DN */ UDNS_API unsigned dns_dntop_size(dnscc_t *dn); /* either wrappers or reimplementations for inet_ntop() and inet_pton() */ UDNS_API const char *dns_ntop(int af, const void *src, char *dst, unsigned size); UDNS_API int dns_pton(int af, const char *src, void *dst); /**************************************************************************/ /**************** DNS raw packet layout ***********************************/ enum dns_rcode { /* reply codes */ DNS_R_NOERROR = 0, /* ok, no error */ DNS_R_FORMERR = 1, /* format error */ DNS_R_SERVFAIL = 2, /* server failed */ DNS_R_NXDOMAIN = 3, /* domain does not exists */ DNS_R_NOTIMPL = 4, /* not implemented */ DNS_R_REFUSED = 5, /* query refused */ /* these are for BIND_UPDATE */ DNS_R_YXDOMAIN = 6, /* Name exists */ DNS_R_YXRRSET = 7, /* RRset exists */ DNS_R_NXRRSET = 8, /* RRset does not exist */ DNS_R_NOTAUTH = 9, /* Not authoritative for zone */ DNS_R_NOTZONE = 10, /* Zone of record different from zone section */ /*ns_r_max = 11,*/ /* The following are TSIG extended errors */ DNS_R_BADSIG = 16, DNS_R_BADKEY = 17, DNS_R_BADTIME = 18 }; static __inline unsigned dns_get16(dnscc_t *s) { return ((unsigned)s[0]<<8) | s[1]; } static __inline unsigned dns_get32(dnscc_t *s) { return ((unsigned)s[0]<<24) | ((unsigned)s[1]<<16) | ((unsigned)s[2]<<8) | s[3]; } static __inline dnsc_t *dns_put16(dnsc_t *d, unsigned n) { *d++ = (dnsc_t)((n >> 8) & 255); *d++ = (dnsc_t)(n & 255); return d; } static __inline dnsc_t *dns_put32(dnsc_t *d, unsigned n) { *d++ = (dnsc_t)((n >> 24) & 255); *d++ = (dnsc_t)((n >> 16) & 255); *d++ = (dnsc_t)((n >> 8) & 255); *d++ = (dnsc_t)(n & 255); return d; } /* DNS Header layout */ enum { /* bytes 0:1 - query ID */ DNS_H_QID1 = 0, DNS_H_QID2 = 1, DNS_H_QID = DNS_H_QID1, #define dns_qid(pkt) dns_get16((pkt)+DNS_H_QID) /* byte 2: flags1 */ DNS_H_F1 = 2, DNS_HF1_QR = 0x80, /* query response flag */ #define dns_qr(pkt) ((pkt)[DNS_H_F1]&DNS_HF1_QR) DNS_HF1_OPCODE = 0x78, /* opcode, 0 = query */ #define dns_opcode(pkt) (((pkt)[DNS_H_F1]&DNS_HF1_OPCODE)>>3) DNS_HF1_AA = 0x04, /* auth answer */ #define dns_aa(pkt) ((pkt)[DNS_H_F1]&DNS_HF1_AA) DNS_HF1_TC = 0x02, /* truncation flag */ #define dns_tc(pkt) ((pkt)[DNS_H_F1]&DNS_HF1_TC) DNS_HF1_RD = 0x01, /* recursion desired (may be set in query) */ #define dns_rd(pkt) ((pkt)[DNS_H_F1]&DNS_HF1_RD) /* byte 3: flags2 */ DNS_H_F2 = 3, DNS_HF2_RA = 0x80, /* recursion available */ #define dns_ra(pkt) ((pkt)[DNS_H_F2]&DNS_HF2_RA) DNS_HF2_Z = 0x40, /* reserved */ DNS_HF2_AD = 0x20, /* DNSSEC: authentic data */ #define dns_ad(pkt) ((pkt)[DNS_H_F2]&DNS_HF2_AD) DNS_HF2_CD = 0x10, /* DNSSEC: checking disabled */ #define dns_cd(pkt) ((pkt)[DNS_H_F2]&DNS_HF2_CD) DNS_HF2_RCODE = 0x0f, /* response code, DNS_R_XXX above */ #define dns_rcode(pkt) ((pkt)[DNS_H_F2]&DNS_HF2_RCODE) /* bytes 4:5: qdcount, numqueries */ DNS_H_QDCNT1 = 4, DNS_H_QDCNT2 = 5, DNS_H_QDCNT = DNS_H_QDCNT1, #define dns_numqd(pkt) dns_get16((pkt)+4) /* bytes 6:7: ancount, numanswers */ DNS_H_ANCNT1 = 6, DNS_H_ANCNT2 = 7, DNS_H_ANCNT = DNS_H_ANCNT1, #define dns_numan(pkt) dns_get16((pkt)+6) /* bytes 8:9: nscount, numauthority */ DNS_H_NSCNT1 = 8, DNS_H_NSCNT2 = 9, DNS_H_NSCNT = DNS_H_NSCNT1, #define dns_numns(pkt) dns_get16((pkt)+8) /* bytes 10:11: arcount, numadditional */ DNS_H_ARCNT1 = 10, DNS_H_ARCNT2 = 11, DNS_H_ARCNT = DNS_H_ARCNT1, #define dns_numar(pkt) dns_get16((pkt)+10) #define dns_payload(pkt) ((pkt)+DNS_HSIZE) /* EDNS0 (OPT RR) flags (Ext. Flags) */ DNS_EF1_DO = 0x80, /* DNSSEC OK */ }; /* packet buffer: start at pkt, end before pkte, current pos *curp. * extract a DN and set *curp to the next byte after DN in packet. * return -1 on error, 0 if dnsiz is too small, or dnlen on ok. */ UDNS_API int dns_getdn(dnscc_t *pkt, dnscc_t **curp, dnscc_t *end, dnsc_t *dn, unsigned dnsiz); /* skip the DN at position cur in packet ending before pkte, * return pointer to the next byte after the DN or NULL on error */ UDNS_API dnscc_t * dns_skipdn(dnscc_t *end, dnscc_t *cur); struct dns_rr { /* DNS Resource Record */ dnsc_t dnsrr_dn[DNS_MAXDN]; /* the DN of the RR */ enum dns_class dnsrr_cls; /* Class */ enum dns_type dnsrr_typ; /* Type */ unsigned dnsrr_ttl; /* Time-To-Live (TTL) */ unsigned dnsrr_dsz; /* data size */ dnscc_t *dnsrr_dptr; /* pointer to start of data */ dnscc_t *dnsrr_dend; /* past end of data */ }; struct dns_parse { /* RR/packet parsing state */ dnscc_t *dnsp_pkt; /* start of the packet */ dnscc_t *dnsp_end; /* end of the packet */ dnscc_t *dnsp_cur; /* current packet position */ dnscc_t *dnsp_ans; /* start of answer section */ int dnsp_rrl; /* number of RRs left to go */ int dnsp_nrr; /* RR count so far */ unsigned dnsp_ttl; /* TTL value so far */ dnscc_t *dnsp_qdn; /* the RR DN we're looking for */ enum dns_class dnsp_qcls; /* RR class we're looking for or 0 */ enum dns_type dnsp_qtyp; /* RR type we're looking for or 0 */ dnsc_t dnsp_dnbuf[DNS_MAXDN]; /* domain buffer */ }; /* initialize the parse structure */ UDNS_API void dns_initparse(struct dns_parse *p, dnscc_t *qdn, dnscc_t *pkt, dnscc_t *cur, dnscc_t *end); /* search next RR, <0=error, 0=no more RRs, >0 = found. */ UDNS_API int dns_nextrr(struct dns_parse *p, struct dns_rr *rr); UDNS_API void dns_rewind(struct dns_parse *p, dnscc_t *qdn); /**************************************************************************/ /**************** Resolver Context ****************************************/ /* default resolver context */ UDNS_DATA_API extern struct dns_ctx dns_defctx; /* reset resolver context to default state, close it if open, drop queries */ UDNS_API void dns_reset(struct dns_ctx *ctx); /* reset resolver context and read in system configuration */ UDNS_API int dns_init(struct dns_ctx *ctx, int do_open); /* return new resolver context with the same settings as copy */ UDNS_API struct dns_ctx * dns_new(const struct dns_ctx *copy); /* free resolver context returned by dns_new(); all queries are dropped */ UDNS_API void dns_free(struct dns_ctx *ctx); /* add nameserver for a resolver context (or reset nslist if serv==NULL) */ UDNS_API int dns_add_serv(struct dns_ctx *ctx, const char *serv); /* add nameserver using struct sockaddr structure (with ports) */ UDNS_API int dns_add_serv_s(struct dns_ctx *ctx, const struct sockaddr *sa); /* add search list element for a resolver context (or reset it if srch==NULL) */ UDNS_API int dns_add_srch(struct dns_ctx *ctx, const char *srch); /* set options for a resolver context */ UDNS_API int dns_set_opts(struct dns_ctx *ctx, const char *opts); enum dns_opt { /* options */ DNS_OPT_FLAGS, /* flags, DNS_F_XXX */ DNS_OPT_TIMEOUT, /* timeout in secounds */ DNS_OPT_NTRIES, /* number of retries */ DNS_OPT_NDOTS, /* ndots */ DNS_OPT_UDPSIZE, /* EDNS0 UDP size */ DNS_OPT_PORT, /* port to use */ }; /* set or get (if val<0) an option */ UDNS_API int dns_set_opt(struct dns_ctx *ctx, enum dns_opt opt, int val); enum dns_flags { DNS_NOSRCH = 0x00010000, /* do not perform search */ DNS_NORD = 0x00020000, /* request no recursion */ DNS_AAONLY = 0x00040000, /* set AA flag in queries */ DNS_SET_DO = 0x00080000, /* set EDNS0 "DO" bit (DNSSEC OK) */ DNS_SET_CD = 0x00100000, /* set CD bit (DNSSEC: checking disabled) */ }; /* set the debug function pointer */ typedef void (dns_dbgfn)(int code, const struct sockaddr *sa, unsigned salen, dnscc_t *pkt, int plen, const struct dns_query *q, void *data); UDNS_API void dns_set_dbgfn(struct dns_ctx *ctx, dns_dbgfn *dbgfn); /* open and return UDP socket */ UDNS_API int dns_open(struct dns_ctx *ctx); /* return UDP socket or -1 if not open */ UDNS_API int dns_sock(const struct dns_ctx *ctx); /* close the UDP socket */ UDNS_API void dns_close(struct dns_ctx *ctx); /* return number of requests queued */ UDNS_API int dns_active(const struct dns_ctx *ctx); /* return status of the last operation */ UDNS_API int dns_status(const struct dns_ctx *ctx); UDNS_API void dns_setstatus(struct dns_ctx *ctx, int status); /* handle I/O event on UDP socket */ UDNS_API void dns_ioevent(struct dns_ctx *ctx, time_t now); /* process any timeouts, return time in secounds to the * next timeout (or -1 if none) but not greather than maxwait */ UDNS_API int dns_timeouts(struct dns_ctx *ctx, int maxwait, time_t now); /* define timer requesting routine to use */ typedef void dns_utm_fn(struct dns_ctx *ctx, int timeout, void *data); UDNS_API void dns_set_tmcbck(struct dns_ctx *ctx, dns_utm_fn *fn, void *data); /**************************************************************************/ /**************** Making Queries ******************************************/ /* query callback routine */ typedef void dns_query_fn(struct dns_ctx *ctx, void *result, void *data); /* query parse routine: raw DNS => application structure */ typedef int dns_parse_fn(dnscc_t *qdn, dnscc_t *pkt, dnscc_t *cur, dnscc_t *end, void **res); enum dns_status { DNS_E_NOERROR = 0, /* ok, not an error */ DNS_E_TEMPFAIL = -1, /* timeout, SERVFAIL or similar */ DNS_E_PROTOCOL = -2, /* got garbled reply */ DNS_E_NXDOMAIN = -3, /* domain does not exists */ DNS_E_NODATA = -4, /* domain exists but no data of reqd type */ DNS_E_NOMEM = -5, /* out of memory while processing */ DNS_E_BADQUERY = -6 /* the query is malformed */ }; /* submit generic DN query */ UDNS_API struct dns_query * dns_submit_dn(struct dns_ctx *ctx, dnscc_t *dn, int qcls, int qtyp, int flags, dns_parse_fn *parse, dns_query_fn *cbck, void *data); /* submit generic name query */ UDNS_API struct dns_query * dns_submit_p(struct dns_ctx *ctx, const char *name, int qcls, int qtyp, int flags, dns_parse_fn *parse, dns_query_fn *cbck, void *data); /* cancel the given async query in progress */ UDNS_API int dns_cancel(struct dns_ctx *ctx, struct dns_query *q); /* resolve a generic query, return the answer */ UDNS_API void * dns_resolve_dn(struct dns_ctx *ctx, dnscc_t *qdn, int qcls, int qtyp, int flags, dns_parse_fn *parse); UDNS_API void * dns_resolve_p(struct dns_ctx *ctx, const char *qname, int qcls, int qtyp, int flags, dns_parse_fn *parse); UDNS_API void * dns_resolve(struct dns_ctx *ctx, struct dns_query *q); /* Specific RR handlers */ #define dns_rr_common(prefix) \ char *prefix##_cname; /* canonical name */ \ char *prefix##_qname; /* original query name */ \ unsigned prefix##_ttl; /* TTL value */ \ int prefix##_nrr /* number of records */ struct dns_rr_null { /* NULL RRset, aka RRset template */ dns_rr_common(dnsn); }; UDNS_API int dns_stdrr_size(const struct dns_parse *p); UDNS_API void * dns_stdrr_finish(struct dns_rr_null *ret, char *cp, const struct dns_parse *p); struct dns_rr_a4 { /* the A RRset */ dns_rr_common(dnsa4); struct in_addr *dnsa4_addr; /* array of addresses, naddr elements */ }; UDNS_API dns_parse_fn dns_parse_a4; /* A RR parsing routine */ typedef void /* A query callback routine */ dns_query_a4_fn(struct dns_ctx *ctx, struct dns_rr_a4 *result, void *data); /* submit A IN query */ UDNS_API struct dns_query * dns_submit_a4(struct dns_ctx *ctx, const char *name, int flags, dns_query_a4_fn *cbck, void *data); /* resolve A IN query */ UDNS_API struct dns_rr_a4 * dns_resolve_a4(struct dns_ctx *ctx, const char *name, int flags); struct dns_rr_a6 { /* the AAAA RRset */ dns_rr_common(dnsa6); struct in6_addr *dnsa6_addr; /* array of addresses, naddr elements */ }; UDNS_API dns_parse_fn dns_parse_a6; /* A RR parsing routine */ typedef void /* A query callback routine */ dns_query_a6_fn(struct dns_ctx *ctx, struct dns_rr_a6 *result, void *data); /* submit AAAA IN query */ UDNS_API struct dns_query * dns_submit_a6(struct dns_ctx *ctx, const char *name, int flags, dns_query_a6_fn *cbck, void *data); /* resolve AAAA IN query */ UDNS_API struct dns_rr_a6 * dns_resolve_a6(struct dns_ctx *ctx, const char *name, int flags); struct dns_rr_ptr { /* the PTR RRset */ dns_rr_common(dnsptr); char **dnsptr_ptr; /* array of PTRs */ }; UDNS_API dns_parse_fn dns_parse_ptr; /* PTR RR parsing routine */ typedef void /* PTR query callback */ dns_query_ptr_fn(struct dns_ctx *ctx, struct dns_rr_ptr *result, void *data); /* submit PTR IN in-addr.arpa query */ UDNS_API struct dns_query * dns_submit_a4ptr(struct dns_ctx *ctx, const struct in_addr *addr, dns_query_ptr_fn *cbck, void *data); /* resolve PTR IN in-addr.arpa query */ UDNS_API struct dns_rr_ptr * dns_resolve_a4ptr(struct dns_ctx *ctx, const struct in_addr *addr); /* the same as above, but for ip6.arpa */ UDNS_API struct dns_query * dns_submit_a6ptr(struct dns_ctx *ctx, const struct in6_addr *addr, dns_query_ptr_fn *cbck, void *data); UDNS_API struct dns_rr_ptr * dns_resolve_a6ptr(struct dns_ctx *ctx, const struct in6_addr *addr); struct dns_mx { /* single MX RR */ int priority; /* MX priority */ char *name; /* MX name */ }; struct dns_rr_mx { /* the MX RRset */ dns_rr_common(dnsmx); struct dns_mx *dnsmx_mx; /* array of MXes */ }; UDNS_API dns_parse_fn dns_parse_mx; /* MX RR parsing routine */ typedef void /* MX RR callback */ dns_query_mx_fn(struct dns_ctx *ctx, struct dns_rr_mx *result, void *data); /* submit MX IN query */ UDNS_API struct dns_query * dns_submit_mx(struct dns_ctx *ctx, const char *name, int flags, dns_query_mx_fn *cbck, void *data); /* resolve MX IN query */ UDNS_API struct dns_rr_mx * dns_resolve_mx(struct dns_ctx *ctx, const char *name, int flags); struct dns_txt { /* single TXT record */ int len; /* length of the text */ dnsc_t *txt; /* pointer to text buffer. May contain nulls. */ }; struct dns_rr_txt { /* the TXT RRset */ dns_rr_common(dnstxt); struct dns_txt *dnstxt_txt; /* array of TXT records */ }; UDNS_API dns_parse_fn dns_parse_txt; /* TXT RR parsing routine */ typedef void /* TXT RR callback */ dns_query_txt_fn(struct dns_ctx *ctx, struct dns_rr_txt *result, void *data); /* submit TXT query */ UDNS_API struct dns_query * dns_submit_txt(struct dns_ctx *ctx, const char *name, int qcls, int flags, dns_query_txt_fn *cbck, void *data); /* resolve TXT query */ UDNS_API struct dns_rr_txt * dns_resolve_txt(struct dns_ctx *ctx, const char *name, int qcls, int flags); struct dns_srv { /* single SRV RR */ int priority; /* SRV priority */ int weight; /* SRV weight */ int port; /* SRV port */ char *name; /* SRV name */ }; struct dns_rr_srv { /* the SRV RRset */ dns_rr_common(dnssrv); struct dns_srv *dnssrv_srv; /* array of SRVes */ }; UDNS_API dns_parse_fn dns_parse_srv; /* SRV RR parsing routine */ typedef void /* SRV RR callback */ dns_query_srv_fn(struct dns_ctx *ctx, struct dns_rr_srv *result, void *data); /* submit SRV IN query */ UDNS_API struct dns_query * dns_submit_srv(struct dns_ctx *ctx, const char *name, const char *srv, const char *proto, int flags, dns_query_srv_fn *cbck, void *data); /* resolve SRV IN query */ UDNS_API struct dns_rr_srv * dns_resolve_srv(struct dns_ctx *ctx, const char *name, const char *srv, const char *proto, int flags); /* NAPTR (RFC3403) RR type */ struct dns_naptr { /* single NAPTR RR */ int order; /* NAPTR order */ int preference; /* NAPTR preference */ char *flags; /* NAPTR flags */ char *service; /* NAPTR service */ char *regexp; /* NAPTR regexp */ char *replacement; /* NAPTR replacement */ }; struct dns_rr_naptr { /* the NAPTR RRset */ dns_rr_common(dnsnaptr); struct dns_naptr *dnsnaptr_naptr; /* array of NAPTRes */ }; UDNS_API dns_parse_fn dns_parse_naptr; /* NAPTR RR parsing routine */ typedef void /* NAPTR RR callback */ dns_query_naptr_fn(struct dns_ctx *ctx, struct dns_rr_naptr *result, void *data); /* submit NAPTR IN query */ UDNS_API struct dns_query * dns_submit_naptr(struct dns_ctx *ctx, const char *name, int flags, dns_query_naptr_fn *cbck, void *data); /* resolve NAPTR IN query */ UDNS_API struct dns_rr_naptr * dns_resolve_naptr(struct dns_ctx *ctx, const char *name, int flags); UDNS_API struct dns_query * dns_submit_a4dnsbl(struct dns_ctx *ctx, const struct in_addr *addr, const char *dnsbl, dns_query_a4_fn *cbck, void *data); UDNS_API struct dns_query * dns_submit_a4dnsbl_txt(struct dns_ctx *ctx, const struct in_addr *addr, const char *dnsbl, dns_query_txt_fn *cbck, void *data); UDNS_API struct dns_rr_a4 * dns_resolve_a4dnsbl(struct dns_ctx *ctx, const struct in_addr *addr, const char *dnsbl); UDNS_API struct dns_rr_txt * dns_resolve_a4dnsbl_txt(struct dns_ctx *ctx, const struct in_addr *addr, const char *dnsbl); UDNS_API struct dns_query * dns_submit_a6dnsbl(struct dns_ctx *ctx, const struct in6_addr *addr, const char *dnsbl, dns_query_a4_fn *cbck, void *data); UDNS_API struct dns_query * dns_submit_a6dnsbl_txt(struct dns_ctx *ctx, const struct in6_addr *addr, const char *dnsbl, dns_query_txt_fn *cbck, void *data); UDNS_API struct dns_rr_a4 * dns_resolve_a6dnsbl(struct dns_ctx *ctx, const struct in6_addr *addr, const char *dnsbl); UDNS_API struct dns_rr_txt * dns_resolve_a6dnsbl_txt(struct dns_ctx *ctx, const struct in6_addr *addr, const char *dnsbl); UDNS_API struct dns_query * dns_submit_rhsbl(struct dns_ctx *ctx, const char *name, const char *rhsbl, dns_query_a4_fn *cbck, void *data); UDNS_API struct dns_query * dns_submit_rhsbl_txt(struct dns_ctx *ctx, const char *name, const char *rhsbl, dns_query_txt_fn *cbck, void *data); UDNS_API struct dns_rr_a4 * dns_resolve_rhsbl(struct dns_ctx *ctx, const char *name, const char *rhsbl); UDNS_API struct dns_rr_txt * dns_resolve_rhsbl_txt(struct dns_ctx *ctx, const char *name, const char *rhsbl); /**************************************************************************/ /**************** Names, Names ********************************************/ struct dns_nameval { int val; const char *name; }; UDNS_DATA_API extern const struct dns_nameval dns_classtab[]; UDNS_DATA_API extern const struct dns_nameval dns_typetab[]; UDNS_DATA_API extern const struct dns_nameval dns_rcodetab[]; UDNS_API int dns_findname(const struct dns_nameval *nv, const char *name); #define dns_findclassname(cls) dns_findname(dns_classtab, (cls)) #define dns_findtypename(type) dns_findname(dns_typetab, (type)) #define dns_findrcodename(rcode) dns_findname(dns_rcodetab, (rcode)) UDNS_API const char *dns_classname(enum dns_class cls); UDNS_API const char *dns_typename(enum dns_type type); UDNS_API const char *dns_rcodename(enum dns_rcode rcode); const char *_dns_format_code(char *buf, const char *prefix, int code); UDNS_API const char *dns_strerror(int errnum); /* simple pseudo-random number generator, code by Bob Jenkins */ struct udns_jranctx { /* the context */ unsigned a, b, c, d; }; /* initialize the RNG with a given seed */ UDNS_API void udns_jraninit(struct udns_jranctx *x, unsigned seed); /* return next random number. 32bits on most platforms so far. */ UDNS_API unsigned udns_jranval(struct udns_jranctx *x); #ifdef __cplusplus } /* extern "C" */ #endif #endif /* include guard */ udns-0.6/udns.30000644000175000017500000016061714650630470011553 0ustar mjtmjt.\" udns.3 .\" udns library manpage .\" .\" Copyright (C) 2005-2014 Michael Tokarev .\" This file is part of UDNS library, an async DNS stub resolver. .\" .\" This library is free software; you can redistribute it and/or .\" modify it under the terms of the GNU Lesser General Public .\" License as published by the Free Software Foundation; either .\" version 2.1 of the License, or (at your option) any later version. .\" .\" This library is distributed in the hope that it will be useful, .\" but WITHOUT ANY WARRANTY; without even the implied warranty of .\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU .\" Lesser General Public License for more details. .\" .\" You should have received a copy of the GNU Lesser General Public .\" License along with this library, in file named COPYING.LGPL; if not, .\" write to the Free Software Foundation, Inc., 59 Temple Place, .\" Suite 330, Boston, MA 02111-1307 USA .TH udns 3 "Jan 2014" "Library Functions" .SH NAME udns \- stub DNS resolver library .SH SYNOPSYS .nf #include struct \fBdns_ctx\fR; struct \fBdns_query\fR; extern struct dns_ctx \fBdns_defctx\fR; struct dns_ctx *\fIctx\fR; typedef void \fBdns_query_fn\fR(\fIctx\fR, void *\fIresult\fR, void *\fIdata\fR); typedef int \fBdns_parse_fn\fR(const unsigned char *\fIqnd\fR, const unsigned char *\fIpkt\fR, const unsigned char *\fIcur\fR, const unsigned char *\fIend\fR, void **\fIresultp\fR); \fBcc\fR ... -l\fBudns\fR .fi .SH DESCRIPTION .PP The DNS library, \fBudns\fR, implements thread-safe stub DNS resolver functionality, which may be used both traditional, synchronous way and asynchronously, with application-supplied event loop. .PP While DNS works with both TCP and UDP, performing UDP query first and if the result does not fit in UDP buffer (512 bytes max for original DNS protocol), retrying the query over TCP, the library uses UDP only, but uses EDNS0 (RFC2671) extensions which allows larger UDP buffers. .PP The library uses single UDP socket to perform all operations even when asking multiple nameservers. This way, it is very simple to use the library in asynchronous event-loop applications: an application should add only single socket to the set of filedescriptors it monitors for I/O. .PP The library uses two main objects, \fIresolver context\fR of type \fBstruct\ dns_ctx\fR, and \fIquery structure\fR of type \fBstruct\ dns_query\fR, both are opaque for an application. Resolver context holds global information about the resolver, such as list of nameservers to use, list of active requests and the like. Query objects holds information about a single DNS query in progress and are allocated/processed/freed by the library. Pointer to query structure may be treated as an identifier of an in-progress query and may be used to cancel the asynchronous query or to wait for it to complete. .PP Asynchronous interface works as follows. An application initializes resolver context, submits any number of queries for it using one of supplied \fBdns_submit_\fIXXX\fR() routines (each return the query identifier as pointer to query structure), waits for input on the UDP socket used by the library, and gives some control to the library by calling \fBdns_ioevent\fR() and \fBdns_timeouts\fR() routines when appropriate. The library performs all necessary processing and executes application supplied callback routine when a query completes (either successefully or not), giving it the result if any, pointer to the resolver context (from which completion status may be obtained), and the data pointer supplied by an application when the query has been submitted. When submitting a query, an application requests how to handle the reply -- to either return raw DNS reply packet for its own low-level processing, or it may provide an address of \fIparsing routine\fR of type \fBdns_parse_fn\fR to perform conversion of on-wire format into easy to use data structure (the library provides parsing routines for several commonly used resource record types, as well as type-safe higher-level interface that requests parsing automatically). The I/O monitoring and timeout handling may be either traditional select() or poll() based, or any callback-driven technique may be used. .PP Additionally, the library provides traditional synchronous interface, which may be intermixed with asynchronous calls (during synchronous query processing, other asynchronous queries for the same resolver context continued to be processed as usual). An application uses one of numerous \fBdns_resolve_\fIXXX\fR() routines provided by the library to perform a query. As with asynchronous interface, an application may either request to return raw DNS packet or type-specific data structure by providing the parsing routine to handle the reply. Every routine from \fBdns_resolve_\fIXXX\fR() series return pointer to result or NULL in case of any error. Query completion status (or length of the raw DNS packet) is available from the resolver context using \fBdns_status\fR() routine, the same way as for the asynchronous interface. .PP Internally, library uses on-wire format of domain names, referred to as \fIDN format\fR in this manual page. This is a series of domain \fIlabels\fR with preceding length byte, terminated by zero-length label which is integral part of the DN format. There are several routines provided to convert from traditional asciiz string to DN and back. Higher-level type-specific query interface hides the DN format from an application. .SH "COMMON DEFINITIONS" .PP Every DNS Resource Record (RR) has a \fItype\fR and a \fIclass\fR. The library defines several integer constants, \fBDNS_C_\fIXXX\fR and \fBDNS_T_\fIXXX\fR, to use as symbolic names for RR classes and types, such as \fBDNS_C_IN\fR for Internet class, \fBDNS_T_A\fR for IPv4 address record type and so on. See udns.h header file for complete list of all such constants. .PP The following constants are defined in udns.h header file: .IP "\fBDNS_MAXDN\fR (255 bytes)" Maximum length of the domain name in internal (on-wire) DN format. .IP "\fBDNS_MAXLABEL\fR (63 bytes)" Maximum length of a single label in DN format. .IP "\fBDNS_MAXNAME\fR (1024 bytes)" Maximum length of asciiz format of a domain name. .IP "\fBDNS_HSIZE\fR (12 bytes)" Size of header in DNS packet. .IP "\fBDNS_PORT\fR (53)" Default port to use when contacting a DNS server. .IP "\fBDNS_MAXSERV\fR (6 servers)" Maximum number of DNS servers to use. .IP "\fBDNS_MAXPACKET\fR (512 bytes)" Maximum length of DNS UDP packet as specified by original DNS protocol .IP "\fBDNS_EDNS0PACKET\fR (4096 bytes)" Default length of DNS UDP packet (with EDNS0 extensions) the library uses. Note that recursive nameservers usually resides near the client asking them to resolve names, e.g. on the same LAN segment or even on the same host, so UDP packet fragmentation isn't a problem in most cases. Note also that the size of actual packets will be as many bytes as actual reply size requires, which is smaller than this value in almost all cases. .PP Additionally, several constants are defined to simplify work with raw DNS packets, such as DNS response codes (\fBDNS_R_\fIXXX\fR), DNS header layout (\fBDNS_H_\fIXXX\fR) and others. Again, see udns.h for complete list. Library error codes (\fBDNS_E_\fIXXX\fR) are described later in this manual page. .SH "RESOLVER CONTEXT" .PP Resolver context, of type \fBstruct\ dns_ctx\fR, is an object which is opaque to an application. Several routines provided by the library to initialize, copy and free resolver contexts. Most other high-level routines in this library expects a pointer to resolver context, \fIctx\fR, as the first argument. There is a default resolver context available, named \fBdns_defctx\fR. When the context pointer \fIctx\fR passed to a routine is NULL, \fBdns_defctx\fR is used. Several resolver contexts may be active at the same time, for example, when an application is multi-threaded and each thread uses resolver. .PP In order to use the library, an application should initialize and open one or more resolver context objects. These are two separate actions, performed by \fBdns_init\fR() (or \fBdns_reset\fR()), and \fBdns_open\fR(). Between the two calls, an application is free to pefrorm additional initialisation, such as setting custom nameservers, options or domain search lists. Optionally, in case no additional custom initialisation is required, \fBdns_init\fR() may open the context if \fIdo_open\fR argument (see below) is non-zero. .PP When initializing resolver context, the library uses information from system file /etc/resolv.conf (see \fBresolv.conf\fR(5)), consults environment variables \fB$LOCALDOMAIN\fR, \fB$NSCACHEIP\fR, \fB$NAMESERVERS\fR and \fB$RES_OPTIONS\fR, and local host name to obtain list of local nameservers, domain name search list and various resolver options. .PP The following routines to initialize resolver context are available: .PP .nf void \fBdns_reset\fR(\fIctx\fR) int \fBdns_init\fR(\fIctx\fR, int \fIdo_open\fR) .fi .RS \fBdns_reset\fR() resets a given resolver context to default values, preparing it to be opened by \fBdns_open\fR(). It is ok to call this routine against opened and active context - all active queries will be dropped, sockets will be closed and so on. This routine does not initialize any parameters from system configuration files, use \fBdns_init\fR() for this. There's no error return - operation always succeeds. \fBdns_init\fR() does everything \fBdns_reset\fR() does, plus initializes various parameters of the context according to system configuration and process environment variables. If \fIdo_open\fR is non-zero, \fBdns_init\fR() calls \fIdns_open\fR(), so that the whole library initialisation is performed in a single step. .RE .PP .nf struct dns_ctx *\fBdns_new\fR(struct dns_ctx *\fIcopy\fR) void \fBdns_free\fR(\fIctx\fR) .fi .RS \fBdns_new\fR() allocates new resolver context and copies all parameters for a given resolver context \fIcopy\fR, or default context if \fIcopy\fR is NULL, and returns pointer to the newly allocated context. The context being copied should be initialized. \fBdns_new\fR() may fail if there's no memory available to make a copy of \fIcopy\fR, in which case the routine will return NULL pointer. \fBdns_free\fR() is used to close associated socket and free resolver context resources and cancelling (abandoming) all active queries associated with it. It's an error to free \fBdns_defctx\fR, only dynamically allocated contexts returned by \fBdns_new\fR() are allowed to be freed by \fBdns_free\fR(). .RE .PP .nf int \fBdns_add_serv\fR(\fIctx\fR, const char *\fIservaddr\fR) int \fBdns_add_serv_s\fR(\fIctx\fR, const struct sockaddr *\fIsa\fR) int \fBdns_add_srch\fR(\fIctx\fR, const char *\fIsrch\fR) .fi .RS Add an element to list of nameservers (\fBdns_add_serv\fR(), as asciiz-string \fIservaddr\fR with an IP address of the nameserver, and \fBdns_add_serv_s\fR(), as initialized socket address \fIsa\fR), or search list (\fBdns_add_srch\fR(), as a pointer to domain name) for the given context \fIctx\fR. If the last argument is a NULL pointer, the corresponding list (search or nameserver) is reset instead. Upon successeful completion, each routine returns new number of elements in the list in question. On error, negative value is returned and global variable \fBerrno\fR is set appropriately. It is an error to call any of this functions if the context is opened (after \fBdns_open\fR() or \fBdns_init\fR() with non-zero argument). .RE .PP .nf int \fBdns_set_opts\fR(\fIctx\fR, const char *\fIopts\fR) .fi .RS set resolver context options from \fIopts\fR string, in the same way as processing \fBoptions\fR statement in resolv.conf and \fB$RES_OPTIONS\fR environment variable. Return number of unrecognized/invalid options found (all recognized and valid options gets processed). .RE .PP .nf void \fBdns_set_opt\fR(\fIctx\fR, int \fIopt\fR, \fIval\fR) .fi .RS .B TODO The \fIflags\fR argument is a bitmask with the following bits defined: .IP \fBDNS_NOSRCH\fR do not perform domain name search in search list. .IP \fBDNS_NORD\fR do not request recursion when performing queries (i.e. don't set RD flag in querues). .IP \fBDNS_AAONLY\fR request authoritative answers only (i.e. set AA flag in queries). .RE .PP .nf int \fBdns_open\fR(\fIctx\fR) int \fBdns_sock\fR(const \fIctx\fR) void \fBdns_close\fR(\fIctx\fR) .fi .RS \fBdns_open\fR() opens the UDP socket used for queries if not already open, and return associated filedescriptor (or negative value in case of error). Before any query can be submitted, the context should be opened using this routine. And before opening, the context should be initialized. \fBdns_sock\fR() return the UDP socket if open, or -1 if not. \fBdns_close\fR() closes the UDP socket if it was open, and drops all active queries if any. .RE .PP .nf int \fBdns_active\fR(const \fIctx\fR) .fi .RS return number of active queries queued for the given context \fIctx\fR, or zero if none. .RE .PP .nf int \fBdns_status\fR(const \fIctx\fR) .fi .RS return status code from last operation. When using synchronous interface, this is the query completion status of the last query. With asynchronous interface, from within the callback routine, this is the query completion status of the query for which the callback is being called. When query submission fails, this is the error code indicating failure reason. All error codes are negative and are represented by \fBDNS_E_\fIXXX\fR constants described below. .RE .PP .nf void \fBdns_ioevent\fR(\fIctx\fR, time_t \fInow\fR) .fi .RS this routine may be called by an application to process I/O events on the UDP socket used by the library, as returned by \fBdns_sock\fR(). The routine tries to receive incoming UDP datagram from the socket and process it. The socket is set up to be non-blocking, so it is safe to call the routine even if there's no data to read. The routine will process as many datagrams as are queued for the socket, so it is safe to use it with either level-triggered or edge-triggered I/O monitoring model. The \fInow\fR argument is either a current time as returned by \fBtime\fR(), or 0, in which case the routine will obtain current time by it's own. .RE .PP .nf int \fBdns_timeouts\fR(\fIctx\fR, int \fImaxwait\fR, time_t \fInow\fR) .fi .RS process any pending timeouts and return number of secounds from current time (\fInow\fR if it is not 0) to the time when the library wants the application to pass it control to process more queued requests. In case when there are no requests pending, this time is -1. The routine will not request a time larger than \fImaxwait\fR secounds if it is greather or equal to zero. If \fInow\fR is 0, the routine will obtain current time by it's own; when it is not 0, it should contain current time as returned by \fBtime\fR(). .RE .PP .nf typedef void \fBdns_utm_fn\fR(\fIctx\fR, int \fItimeout\fR, void *\fIdata\fR) void \fBdns_set_tmcbck\fR(\fIctx\fR, dns_utm_fn *\fIutmfn\fR, void *\fIdata\fR) .fi .RS An application may use custom callback-based I/O multiplexing mechanism. Usually such a mechanism have concept of a \fItimer\fR, and an ability to register a timer event in a form of a callback routine which will be executed after certain amount of time. In order to use such an event mechanism, udns provides an ability to register and de-register timer events necessary for internal processing using whatever event mechanism an application uses. For this to work, it is possible to assotiate a pointer to a routine that will perform necessary work for (de)registering timer events with a given resolver context, and udns will call that routine at appropriate times. Prototype of such a routine is shown by \fBdns_utm_fn\fR typedef above. Libudns assotiates single timer with resolver context. User-supplied \fIutmfn\fR routine will be called by the library with the following arguments: .IP "\fIctx\fR == NULL" delete user timer, at context free time or when an application changes user timer request routine using \fBdns_set_tmcbck\fR(); .IP "\fIctx\fR != NULL, \fItimeout\fR < 0" don't fire timer anymore, when there are no active requests; .IP "\fIctx\fR != NULL, \fItimeout\fR == 0" fire timer at the next possibility, but not immediately; .IP "\fIctx\fR != NULL, \fItimeout\fR > 0" fire timer after \fItimeout\fR seconds after now. .PP The \fIdata\fR argument passed to the routine will be the same as passed to \fBdns_set_tmcbck\fR(). .PP When a timer expires, an application should call \fBdns_timeouts\fR() routine (see below). Non-callback timer usage is provided too. .RE .PP .B XXXX TODO: some more resolver context routines, like dns_set_dbgfn() etc. .SH "QUERY INTERFACE" .PP There are two ways to perform DNS queries: traditional synchronous way, when udns performs all the necessary processing and return control to the application only when the query completes, and asynchronous way, when an application submits one or more queries to the library using given resolver context, and waits for completion by monitoring filedescriptor used by library and calling library routines to process input on that filedescriptor. Asynchronous mode works with callback routines: an application supplies an address of a routine to execute when the query completes, and a data pointer, which is passed to the callback routine. .PP Queries are submitted to the library in a form of \fBstruct\ dns_query\fR. To perform asynchronous query, an application calls one of the \fBdns_submit_\fIXXX\fR() rounines, and provides necessary information for a callback, together with all the query parameters. When the query completes, library will call application-supplied callback routine, giving it the resolver context (which holds query completion status), dynamically allocated result (which will be either raw DNS packet or, if applicatin requested parsing the result by specifying non-NULL parse routine, ready-to-use type-specific structure), and a data pointer provided by an application when it submitted the query. It is the application who's responsible for freeing the result memory. .PP Generic query callback routine looks like this: .nf typedef void \fBdns_query_fn\fR(\fIctx\fR, void *\fIresult\fR, void *\fIdata\fR) .fi Type-specific query interface expects similar form of callback routine with the only difference in type of \fBresult\fR argument, which will be pointer to specific data structure (decoded reply) instead of this void pointer to raw DNS packet data. .PP Result parsing routine looks like this: .nf typedef int \fBdns_parse_fn\fR(const unsigned char *\fIqdn\fR, const unsigned char *\fIpkt\fR, const unsigned char *\fIcur\fR, const unsigned char *\fIend\fR, void **\fIresultp\fR); .fi When called by the library, the arguments are as follows: \fIpkt\fR points to the start of the packet received; \fIend\fR points past the end of the packet received; \fIcur\fR points past the query DN in the query section of the packet; \fIqdn\fR points to the original query DN. The routine should allocate a single buffer to hold the result, parse the reply filling in the buffer, and return the buffer using \fIresultp\fR argument. It returns 0 in case of error, or udns error code (\fBDNS_E_\fIXXX\fR constants) in case of error. Note that by the time when the parse routine is called by the library, packet is already verified to be a reply to the original query, by matching query DN, query class and query type. .PP Type-specific query interface supplies necessary parsing routines automatically. .PP In case of error, query completion status as returned by \fBdns_status\fR(\fIctx\fR), will contain one of the following values: .IP "positive value" length of raw DNS packet if parsing is not requested. .IP 0 the query was successeful and the \fIreply\fR points to type-specific data structure. .IP \fBDNS_E_TEMPFAIL\fR temporary error, the resolver nameserver was not able to process our query or timed out. .IP \fBDNS_E_PROTOCOL\fR protocol error, a nameserver returned malformed reply. .IP \fBDNS_E_NXDOMAIN\fR the domain name does not exist. .IP \fBDNS_E_NODATA\fR there is no data of requested type found. .IP \fBDNS_E_NOMEM\fR out of memory while processing request. .IP \fBDNS_E_BADQUERY\fR some aspect of the query (most common is the domain name in question) is invalid, and the library can't even start a query. .PP Library provides two series of routines which uses similar interface -- one for asynchronous queries and another for synchronous queries. There are two general low-level routines in each series to submit (asynchronous interface) and resolve (synchronous interface) queries, as well as several type-specific routines with more easy-to-use interfaces. To submit an asynchronous query, use one of \fBdns_submit_\fIXXX\fR() routine, each of which accepts query parameters, pointers to callback routine and to callback data, and optional current time hint. Note type-specific \fBdns_submit_\fIXXX\fR() routines expects specific type of the callback routine as well, which accepts reply as a pointer to corresponding structure, not a void pointer). Every \fBdns_submit_\fIXXX\fR() routine return pointer to internal query structure of type struct\ dns_query, used as an identifier for the given query. .PP To resolve a query synchronously, use one of \fBdns_resolve_\fIXXX\fR() routines, which accepts the same query parameters (but not the callback pointers) as corresponding \fBdns_submit_\fIXXX\fR(), and return the query result, which is the same as passed to the callback routine in case of asynchronous interface. .PP In either case, the result memory (if the query completed successefully) is dynamically allocated and should be freed by an application. If the query failed for any reason, the result will be NULL, and error status will be available from \fBdns_status\fR(\fIctx\fR) routine as shown above. .PP .nf struct dns_query * \fBdns_submit_dn\fR(\fIctx\fR, const unsigned char *\fIdn\fR, \fIqcls\fR, \fIqtyp\fR, \fIflags\fR, \fIparse\fR, \fIcbck\fR, \fIdata\fR) struct dns_query * \fBdns_submit_p\fR(\fIctx\fR, const char *\fIname\fR, \fIqcls\fR, \fIqtyp\fR, \fIflags\fR, \fIparse\fR, \fIcbck\fR, \fIdata\fR) enum dns_class \fIqcls\fR; enum dns_type \fIqtyp\fR; int \fIflags\fR; dns_parse_fn *\fIparse\fR; dns_query_fn *\fIcbck\fR; void *\fIdata\fR; .fi .RS submit a query for processing for the given resolver context \fIctx\fR. Two routines differs only in 3rd argument, which is domain name in DN format (\fIdn\fR) or asciiz string (\fIname\fR). The query will be performed for the given domain name, with type \fIqtyp\fR in class \fIqcls\fR, using option bits in \fIflags\fR, using RR parsing routine pointed by \fIparse\fR if not-NULL, and upon completion, \fIcbck\fR function will be called with the \fIdata\fR argument. In case of successeful query submission, the routine return pointer to internal query structure which may be treated as an identifier of the query as used by the library, and may be used as an argument for \fBdns_cancel\fR() routine. In case of error, NULL will be returned, and context error status (available using \fIdns_status\fR() routine) will be set to corresponding error code, which in this case may be DNS_E_BADQUERY if the \fIname\fR of \fIdn\fR is invalid, DNS_E_NOMEM if there's no memory available to allocate query structure, or DNS_E_TEMPFAIL if an internal error occurred. .RE .PP .nf void *\fBdns_resolve_dn\fR(\fIctx\fR, const unsigned char *\fIdn\fR, \fIqcls\fR, \fIqtyp\fR, \fIflags\fR, \fIparse\fR); void *\fBdns_resolve_p\fR(\fIctx\fR, const char *\fIname\fR, \fIqcls\fR, \fIqtyp\fR, \fIflags\fR, \fIparse\fR) enum dns_class \fIqcls\fR; enum dns_type \fIqtyp\fR; int \fIflags\fR; dns_parse_fn *\fIparse\fR; .fi .RS synchronous interface. The routines perform all the steps necessary to resolve the given query and return the result. If there's no positive result for any reason, all the routines return NULL, and set context error status (available using \fBdns_status\fR() routine) to indicate the error code. If the query was successeful, context status code will contain either the length of the raw DNS reply packet if \fIparse\fR argument was NULL (in which case the return value is pointer to the reply DNS packet), or 0 (in which case the return value is the result of \fIparse\fR routine). If the query successeful (return value is not NULL), the memory returned was dynamically allocated by the library and should be free()d by application after use. .RE .PP .nf void *\fBdns_resolve\fR(\fIctx\fR, struct dns_query *\fIq\fR) .fi .RS wait for the given query \fIq\fR, as returned by one of \fBdns_submit_\fIXXX\fR() routines, for completion, and return the result. The callback routine will not be called for this query. After completion, the query identifier \fIq\fR is not valid. Both \fBdns_resolve_dn\fR() and \fBdns_resolve_p\fR() are just wrappers around corresponding submit routines and this \fBdns_resolve\fR() routine. .RE .PP .nf void \fBdns_cancel\fR(\fIctx\fR, struct dns_query *\fIq\fR) .fi .RS cancel an active query \fIq\fR, without calling a callback routine. After completion, the query identifier \fIq\fR is not valid. .RE .SH "TYPE-SPECIFIC QUERIES" .PP In addition to the generic low-level query interface, the library provides a set of routines to perform specific queries in a type-safe manner, as well as parsers for several well-known resource record types. The library implements high-level interface for A, AAAA, PTR, MX and TXT records and DNSBL and RHSBL functionality. These routines returns specific types as result of a query, instead of raw DNS packets. The following types and routines are available. .PP .nf struct \fBdns_rr_null\fR { char *\fBdnsn_qname\fR; /* original query name */ char *\fBdnsn_cname\fR; /* canonical name */ unsigned \fBdnsn_ttl\fR; /* Time-To-Live (TTL) value */ int \fBdnsn_nrr\fR; /* number of records in the set */ }; .fi .PP NULL RR set, used as a base for all other RR type structures. Every RR structure as used by the library have four standard fields as in struct\ \fBdns_rr_null\fR. .SS "IN A Queries" .PP .nf struct \fBdns_rr_a4\fR { /* IN A RRset */ char *\fBdnsa4_qname\fR; /* original query name */ char *\fBdnsa4_cname\fR; /* canonical name */ unsigned \fBdnsa4_ttl\fR; /* Time-To-Live (TTL) value */ int \fBdnsa4_nrr\fR; /* number of addresses in the set */ struct in_addr \fBdnsa4_addr\fR[]; /* array of addresses */ }; typedef void \fBdns_query_a4_fn\fR(\fIctx\fR, struct dns_rr_a4 *\fIresult\fR, \fIdata\fR) dns_parse_fn \fBdns_parse_a4\fB; struct dns_query * \fBdns_submit_a4\fB(\fIctx\fR, const char *\fIname\fR, int \fIflags\fR, dns_query_a4_fn *\fIcbck\fR, \fIdata\fR); struct dns_rr_a4 * \fBdns_resolve_a4\fB(\fIctx\fR, const char *\fIname\fR, int \fIflags\fR); .fi .PP The \fBdns_rr_a4\fR structure holds a result of an \fBIN A\fR query, which is an array of IPv4 addresses. Callback routine for IN A queries expected to be of type \fBdns_query_a4_fn\fR, which expects pointer to \fBdns_rr_a4\fR structure as query result instead of raw DNS packet. The \fBdns_parse_a4\fR() is used to convert raw DNS reply packet into \fBdns_rr_a4\fR structure (it is used internally and may be used directly too with generic query interface). Routines \fBdns_submit_a4\fR() and \fBdns_resolve_a4\fR() are used to perform A IN queries in a type-safe manner. The \fIname\fR parameter is the domain name in question, and \fIflags\fR is query flags bitmask, with one bit, DNS_NOSRCH, of practical interest (if the \fIname\fR is absolute, that is, it ends up with a dot, DNS_NOSRCH flag will be set automatically). .SS "IN AAAA Queries" .PP .nf struct \fBdns_rr_a6\fR { /* IN AAAA RRset */ char *\fBdnsa6_qname\fR; /* original query name */ char *\fBdnsa6_cname\fR; /* canonical name */ unsigned \fBdnsa6_ttl\fR; /* Time-To-Live (TTL) value */ int \fBdnsa6_nrr\fR; /* number of addresses in the set */ struct in6_addr \fBdnsa6_addr\fR[]; /* array of addresses */ }; typedef void \fBdns_query_a6_fn\fR(\fIctx\fR, struct dns_rr_a6 *\fIresult\fR, \fIdata\fR) dns_parse_fn \fBdns_parse_a6\fB; struct dns_query * \fBdns_submit_a6\fB(\fIctx\fR, const char *\fIname\fR, int \fIflags\fR, dns_query_a6_fn *\fIcbck\fR, \fIdata\fR); struct dns_rr_a6 * \fBdns_resolve_a6\fB(\fIctx\fR, const char *\fIname\fR, int \fIflags\fR); .fi .PP The \fBdns_rr_a6\fR structure holds a result of an \fBIN AAAA\fR query, which is an array of IPv6 addresses. Callback routine for IN AAAA queries expected to be of type \fBdns_query_a6_fn\fR, which expects pointer to \fBdns_rr_a6\fR structure as query result instead of raw DNS packet. The \fBdns_parse_a6\fR() is used to convert raw DNS reply packet into \fBdns_rr_a6\fR structure (it is used internally and may be used directly too with generic query interface). Routines \fBdns_submit_a6\fR() and \fBdns_resolve_a6\fR() are used to perform AAAA IN queries in a type-safe manner. The \fIname\fR parameter is the domain name in question, and \fIflags\fR is query flags bitmask, with one bit, DNS_NOSRCH, of practical interest (if the \fIname\fR is absolute, that is, it ends up with a dot, DNS_NOSRCH flag will be set automatically). .SS "IN PTR Queries" .PP .nf struct \fBdns_rr_ptr\fR { /* IN PTR RRset */ char *\fBdnsptr_qname\fR; /* original query name */ char *\fBdnsptr_cname\fR; /* canonical name */ unsigned \fBdnsptr_ttl\fR; /* Time-To-Live (TTL) value */ int \fBdnsptr_nrr\fR; /* number of domain name pointers */ char *\fBdnsptr_ptr\fR[]; /* array of domain name pointers */ }; typedef void \fBdns_query_ptr_fn\fR(\fIctx\fR, struct dns_rr_ptr *\fIresult\fR, \fIdata\fR) dns_parse_fn \fBdns_parse_ptr\fB; struct dns_query * \fBdns_submit_a4ptr\fB(\fIctx\fR, const struct in_addr *\fBaddr\fR, dns_query_ptr_fn *\fIcbck\fR, \fIdata\fR); struct dns_rr_ptr * \fBdns_resolve_a4ptr\fB(\fIctx\fR, const struct in_addr *\fBaddr\fR); struct dns_query * \fBdns_submit_a6ptr\fB(\fIctx\fR, const struct in6_addr *\fBaddr\fR, dns_query_ptr_fn *\fIcbck\fR, \fIdata\fR); struct dns_rr_ptr * \fBdns_resolve_a6ptr\fB(\fIctx\fR, const struct in6_addr *\fBaddr\fR); .fi .PP The \fBdns_rr_ptr\fR structure holds a result of an IN PTR query, which is an array of domain name pointers for a given IPv4 or IPv6 address. Callback routine for IN PTR queries expected to be of type \fBdns_query_ptr_fn\fR, which expects pointer to \fBdns_rr_ptr\fR structure as query result instead of raw DNS packet. The \fBdns_parse_ptr\fR() is used to convert raw DNS reply packet into \fBdns_rr_ptr\fR structure (it is used internally and may be used directly too with generic query interface). Routines \fBdns_submit_a4ptr\fR() and \fBdns_resolve_a4ptr\fR() are used to perform IN PTR queries for IPv4 addresses in a type-safe manner. Routines \fBdns_submit_a6ptr\fR() and \fBdns_resolve_a6ptr\fR() are used to perform IN PTR queries for IPv6 addresses. .SS "IN MX Queries" .PP .nf struct \fBdns_mx\fR { /* single MX record */ int \fBpriority\fR; /* priority value of this MX */ char *\fBname\fR; /* domain name of this MX */ }; struct \fBdns_rr_mx\fR { /* IN MX RRset */ char *\fBdnsmx_qname\fR; /* original query name */ char *\fBdnsmx_cname\fR; /* canonical name */ unsigned \fBdnsmx_ttl\fR; /* Time-To-Live (TTL) value */ int \fBdnsmx_nrr\fR; /* number of mail exchangers in the set */ struct dns_mx \fBdnsmx_mx\fR[]; /* array of mail exchangers */ }; typedef void \fBdns_query_mx_fn\fR(\fIctx\fR, struct dns_rr_mx *\fIresult\fR, \fIdata\fR) dns_parse_fn \fBdns_parse_mx\fB; struct dns_query * \fBdns_submit_mx\fB(\fIctx\fR, const char *\fIname\fR, int \fIflags\fR, dns_query_mx_fn *\fIcbck\fR, \fIdata\fR); struct dns_rr_mx * \fBdns_resolve_mx\fB(\fIctx\fR, const char *\fIname\fR, int \fIflags\fR); .fi .PP The \fBdns_rr_mx\fR structure holds a result of an IN MX query, which is an array of mail exchangers for a given domain. Callback routine for IN MX queries expected to be of type \fBdns_query_mx_fn\fR, which expects pointer to \fBdns_rr_mx\fR structure as query result instead of raw DNS packet. The \fBdns_parse_mx\fR() is used to convert raw DNS reply packet into \fBdns_rr_mx\fR structure (it is used internally and may be used directly too with generic query interface). Routines \fBdns_submit_mx\fR() and \fBdns_resolve_mx\fR() are used to perform IN MX queries in a type-safe manner. The \fIname\fR parameter is the domain name in question, and \fIflags\fR is query flags bitmask, with one bit, DNS_NOSRCH, of practical interest (if the \fIname\fR is absolute, that is, it ends up with a dot, DNS_NOSRCH flag will be set automatically). .SS "TXT Queries" .PP .nf struct \fBdns_txt\fR { /* single TXT record */ int \fBlen\fR; /* length of the text */ unsigned char *\fBtxt\fR; /* pointer to the text */ }; struct \fBdns_rr_txt\fR { /* TXT RRset */ char *\fBdnstxt_qname\fR; /* original query name */ char *\fBdnstxt_cname\fR; /* canonical name */ unsigned \fBdnstxt_ttl\fR; /* Time-To-Live (TTL) value */ int \fBdnstxt_nrr\fR; /* number of text records in the set */ struct dns_txt \fBdnstxt_txt\fR[]; /* array of TXT records */ }; typedef void \fBdns_query_txt_fn\fR(\fIctx\fR, struct dns_rr_txt *\fIresult\fR, \fIdata\fR) dns_parse_fn \fBdns_parse_txt\fB; struct dns_query * \fBdns_submit_txt\fB(\fIctx\fR, const char *\fIname\fR, enum dns_class \fIqcls\fR, int \fIflags\fR, dns_query_txt_fn *\fIcbck\fR, \fIdata\fR); struct dns_rr_txt * \fBdns_resolve_txt\fB(\fIctx\fR, const char *\fIname\fR, enum dns_class \fIqcls\fR, int \fIflags\fR); .fi .PP The \fBdns_rr_txt\fR structure holds a result of a TXT query, which is an array of text records for a given domain name. Callback routine for TXT queries expected to be of type \fBdns_query_txt_fn\fR, which expects pointer to \fBdns_rr_txt\fR structure as query result instead of raw DNS packet. The \fBdns_parse_txt\fR() is used to convert raw DNS reply packet into \fBdns_rr_txt\fR structure (it is used internally and may be used directly too with generic query interface). Routines \fBdns_submit_txt\fR() and \fBdns_resolve_txt\fR() are used to perform IN MX queries in a type-safe manner. The \fIname\fR parameter is the domain name in question, and \fIflags\fR is query flags bitmask, with one bit, DNS_NOSRCH, of practical interest (if the \fIname\fR is absolute, that is, it ends up with a dot, DNS_NOSRCH flag will be set automatically). Note that each TXT string is represented by \fBstruct\ dns_txt\fR, while zero-terminated (and the len field of the structure does not include the terminator), may contain embedded null characters -- content of TXT records is not interpreted by the library in any way. .SS "SRV Queries" .PP .nf struct \fBdns_srv\fR { /* single SRV record */ int \fBpriority\fR; /* priority of the record */ int \fBweight\fR; /* weight of the record */ int \fBport\fR; /* the port number to connect to */ char *\fBname\fR; /* target host name */ }; struct \fBdns_rr_srv\fR { /* SRV RRset */ char *\fBdnssrv_qname\fR; /* original query name */ char *\fBdnssrv_cname\fR; /* canonical name */ unsigned \fBdnssrv_ttl\fR; /* Time-To-Live (TTL) value */ int \fBdnssrv_nrr\fR; /* number of text records in the set */ struct dns_srv \fBdnssrv_srv\fR[]; /* array of SRV records */ }; typedef void \fBdns_query_srv_fn\fR(\fIctx\fR, struct dns_rr_srv *\fIresult\fR, \fIdata\fR) dns_parse_fn \fBdns_parse_srv\fB; struct dns_query * \fBdns_submit_srv\fB(\fIctx\fR, const char *\fIname\fR, const char *\fIservice\fR, const char *\fIprotocol\fR, int \fIflags\fR, dns_query_txt_fn *\fIcbck\fR, \fIdata\fR); struct dns_rr_srv * \fBdns_resolve_srv\fB(\fIctx\fR, const char *\fIname\fR, const char *\fIservice\fR, const char *\fIprotocol\fR, int \fIflags\fR); .fi .PP The \fBdns_rr_srv\fR structure holds a result of an IN SRV (rfc2782) query, which is an array of servers (together with port numbers) which are performing operations for a given \fIservice\fR using given \fIprotocol\fR on a target domain \fIname\fR. Callback routine for IN SRV queries expected to be of type \fBdns_query_srv_fn\fR, which expects pointer to \fBdns_rr_srv\fR structure as query result instead of raw DNS packet. The \fBdns_parse_srv\fR() is used to convert raw DNS reply packet into \fBdns_rr_srv\fR structure (it is used internally and may be used directly too with generic query interface). Routines \fBdns_submit_srv\fR() and \fBdns_resolve_srv\fR() are used to perform IN SRV queries in a type-safe manner. The \fIname\fR parameter is the domain name in question, \fIservice\fR and \fRprotocl\fR specifies the service and the protocol in question (the library will construct query DN according to rfc2782 rules) and may be NULL (in this case the library assumes \fIname\fR parameter holds the complete SRV query), and \fIflags\fR is query flags bitmask, with one bit, DNS_NOSRCH, of practical interest (if the \fIname\fR is absolute, that is, it ends up with a dot, DNS_NOSRCH flag will be set automatically). .SS "NAPTR Queries" .PP .nf struct \fBdns_naptr\fR { /* single NAPTR record */ int \fBorder\fR; /* record order */ int \fBpreference\fR; /* preference of this record */ char *\fBflags\fR; /* application-specific flags */ char *\fBservice\fR; /* service parameter */ char *\fBregexp\fR; /* substitutional regular expression */ char *\fBreplacement\fR; /* replacement string */ }; struct \fBdns_rr_naptr\fR { /* NAPTR RRset */ char *\fBdnsnaptr_qname\fR; /* original query name */ char *\fBdnsnaptr_cname\fR; /* canonical name */ unsigned \fBdnsnaptr_ttl\fR; /* Time-To-Live (TTL) value */ int \fBdnsnaptr_nrr\fR; /* number of text records in the set */ struct dns_naptr \fBdnsnaptr_naptr\fR[]; /* array of NAPTR records */ }; typedef void \fBdns_query_naptr_fn\fR(\fIctx\fR, struct dns_rr_naptr *\fIresult\fR, \fIdata\fR) dns_parse_fn \fBdns_parse_naptr\fB; struct dns_query * \fBdns_submit_naptr\fB(\fIctx\fR, const char *\fIname\fR, int \fIflags\fR, dns_query_txt_fn *\fIcbck\fR, \fIdata\fR); struct dns_rr_naptr * \fBdns_resolve_naptr\fB(\fIctx\fR, const char *\fIname\fR, int \fIflags\fR); .fi .PP The \fBdns_rr_naptr\fR structure holds a result of an IN NAPTR (rfc3403) query. Callback routine for IN NAPTR queries expected to be of type \fBdns_query_naptr_fn\fR, expects pointer to \fBdns_rr_naptr\fR structure as query result instead of raw DNS packet. The \fBdns_parse_naptr\fR() is used to convert raw DNS reply packet into \fBdns_rr_naptr\fR structure (it is used internally and may be used directly too with generic query interface). Routines \fBdns_submit_naptr\fR() and \fBdns_resolve_naptr\fR() are used to perform IN NAPTR queries in a type-safe manner. The \fIname\fR parameter is the domain name in question, and \fIflags\fR is query flags bitmask, with one bit, DNS_NOSRCH, of practical interest (if the \fIname\fR is absolute, that is, it ends up with a dot, DNS_NOSRCH flag will be set automatically). .SS "DNSBL Interface" .PP A DNS-based blocklists, or a DNSBLs, are in wide use nowadays, especially to protect mailservers from spammers. The library provides DNSBL interface, a set of routines to perform queries against DNSBLs. Routines accepts an IP address (IPv4 and IPv6 are both supported) and a base DNSBL zone as query parameters, and returns either \fBdns_rr_a4\fR or \fBdns_rr_txt\fR structure. Note that IPv6 interface return IPv4 RRset. .PP .nf struct dns_query * \fBdns_submit_a4dnsbl\fR(\fIctx\fR, const struct in_addr *\fIaddr\fR, const char *\fIdnsbl\fR, dns_query_a4_fn *\fIcbck\fR, void *\fIdata\fR); struct dns_query * \fBdns_submit_a4dnsbl_txt\fR(\fIctx\fR, const struct in_addr *\fIaddr\fR, const char *\fIdnsbl\fR, dns_query_txt_fn *\fIcbck\fR, void *\fIdata\fR); struct dns_query * \fBdns_submit_a6dnsbl\fR(\fIctx\fR, const struct in6_addr *\fIaddr\fR, const char *\fIdnsbl\fR, dns_query_a4_fn *\fIcbck\fR, void *\fIdata\fR); struct dns_query * \fBdns_submit_a6dnsbl_txt\fR(\fIctx\fR, const struct in6_addr *\fIaddr\fR, const char *\fIdnsbl\fR, dns_query_txt_fn *\fIcbck\fR, void *\fIdata\fR); struct dns_rr_a4 *\fBdns_resolve_a4dnsbl\fR(\fIctx\fR, const struct in_addr *\fIaddr\fR, const char *\fIdnsbl\fR) struct dns_rr_txt *\fBdns_resolve_a4dnsbl_txt\fR(\fIctx\fR, const struct in_addr *\fIaddr\fR, const char *\fIdnsbl\fR) struct dns_rr_a4 *\fBdns_resolve_a6dnsbl\fR(\fIctx\fR, const struct in6_addr *\fIaddr\fR, const char *\fIdnsbl\fR) struct dns_rr_txt *\fBdns_resolve_a6dnsbl_txt\fR(\fIctx\fR, const struct in6_addr *\fIaddr\fR, const char *\fIdnsbl\fR) .fi Perform (submit or resolve) a DNSBL query for the given \fIdnsbl\fR domain and an IP \fIaddr\fR in question, requesting either A or TXT records. .SS "RHSBL Interface" .PP RHSBL is similar to DNSBL, but instead of an IP address, the parameter is a domain name. .PP .nf struct dns_query * \fBdns_submit_rhsbl\fR(\fIctx\fR, const char *\fIname\fR, const char *\fIrhsbl\fR, dns_query_a4_fn *\fIcbck\fR, void *\fIdata\fR); struct dns_query * \fBdns_submit_rhsbl_txt\fR(\fIctx\fR, const char *\fIname\fR, const char *\fIrhsbl\fR, dns_query_txt_fn *\fIcbck\fR, void *\fIdata\fR); struct dns_rr_a4 * \fBdns_resolve_rhsbl\fR(\fIctx\fR, const char *\fIname\fR, const char *\fIrhsbl\fR); struct dns_rr_txt * \fBdns_resolve_rhsbl_txt\fR(\fIctx\fR, const char *\fIname\fR, const char *\fIrhsbl\fR); .fi Perform (submit or resolve) a RHSBL query for the given \fIrhsbl\fR domain and \fIname\fR in question, requesting either A or TXT records. .SH "LOW-LEVEL INTERFACE" .SS "Domain Names (DNs)" .PP A DN is a series of domain name labels each starts with length byte, followed by empty label (label with zero length). The following routines to work with DNs are provided. .PP .nf unsigned \fBdns_dnlen\fR(const unsigned char *\fIdn\fR) .fi .RS return length of the domain name \fIdn\fR, including the terminating label. .RE .PP .nf unsigned \fBdns_dnlabels\fR(const unsigned char *\fIdn\fR) .fi .RS return number of non-zero labels in domain name \fIdn\fR. .RE .PP .nf unsigned \fBdns_dnequal\fR(\fIdn1\fR, \fIdn2\fR) const unsigned char *\fIdn1\fR, *\fIdn2\fR; .fi .RS test whenever the two domain names, \fIdn1\fR and \fIdn2\fR, are equal (case-insensitive). Return domain name length if equal or 0 if not. .RE .PP .nf unsigned \fBdns_dntodn\fR(\fIsdn\fR, \fIddn\fR, \fIdnsiz\fR) const unsigned char *\fIsdn\fR; unsigned char *\fIddn\fR; unsigned \fIdnsiz\fR; .fi .RS copies the source domain name \fIsdn\fR to destination buffer \fIddn\fR of size \fIdnsiz\fR. Return domain name length or 0 if \fIddn\fR is too small. .RE .PP .nf int \fBdns_ptodn\fR(\fIname\fR, \fInamelen\fR, \fIdn\fR, \fIdnsiz\fR, \fIisabs\fR) int \fBdns_sptodn\fR(\fIname\fR, \fIdn\fR, \fIdnsiz\fR) const char *\fIname\fR; unsigned \fInamelen\fR; unsigned char *\fIdn\fR; unsigned \fIdnsiz\fR; int *\fIisabs\fR; .fi .RS convert asciiz name \fIname\fR of length \fInamelen\fR to DN format, placing result into buffer \fIdn\fR of size \fIdnsiz\fR. Return length of the DN if successeful, 0 if the \fIdn\fR buffer supplied is too small, or negative value if \fIname\fR is invalid. If \fIisabs\fR is non-NULL and conversion was successeful, *\fIisabs\fR will be set to either 1 or 0 depending whenever \fIname\fR was absolute (i.e. ending with a dot) or not. Name length, \fInamelength\fR, may be zero, in which case strlen(\fIname\fR) will be used. Second form, \fBdns_sptodn\fR(), is a simplified form of \fBdns_ptodn\fR(), equivalent to .br .nf \fBdns_ptodn\fR(\fIname\fR, 0, \fIdn\fR, \fIdnlen\fR, 0). .fi .RE .PP .nf extern const unsigned char \fBdns_inaddr_arpa_dn\fR[] int \fBdns_a4todn\fR(const struct in_addr *\fIaddr\fR, const unsigned char *\fItdn\fR, unsigned char *\fIdn\fR, unsigned \fIdnsiz\fR) int \fBdns_a4ptodn\fR(const struct in_addr *\fIaddr\fR, const char *\fItname\fR, unsigned char *\fIdn\fR, unsigned \fIdnsiz\fR) extern const unsigned char \fBdns_ip6_arpa_dn\fR[] int \fBdns_a6todn\fR(const struct in6_addr *\fIaddr\fR, const unsigned char *\fItdn\fR, unsigned char *\fIdn\fR, unsigned \fIdnsiz\fR) int \fBdns_a6ptodn\fR(const struct in6_addr *\fIaddr\fR, const char *\fItname\fR, unsigned char *\fIdn\fR, unsigned \fIdnsiz\fR) .fi .RS several variants of routines to convert IPv4 and IPv6 address \fIaddr\fR into reverseDNS-like domain name in DN format, storing result in \fIdn\fR of size \fIdnsiz\fR. \fItdn\fR (or \fItname\fR) is the base zone name, like in-addr.arpa for IPv4 or in6.arpa for IPv6. If \fItdn\fR (or \fItname\fR) is NULL, \fBdns_inaddr_arpa_dn\fR (or \fBdns_ip6_arpa_dn\fR) will be used. The routines may be used to construct a DN for a DNSBL lookup for example. All routines return length of the resulting DN on success, -1 if resulting DN is invalid, or 0 if the \fIdn\fR buffer (\fIdnsiz\fR) is too small. To hold standard rDNS DN, a buffer of size \fBDNS_A4RSIZE\fR (30 bytes) for IPv4 address, or \fBDNS_A6RSIZE\fR (74 bytes) for IPv6 address, is sufficient. .RE .PP .nf int \fBdns_dntop\fR(\fIdn\fR, \fIname\fR, \fInamesiz\fR) const unsigned char *\fIdn\fR; const char *\fIname\fR; unsigned \fInamesiz\fR; .fi .RS convert domain name \fIdn\fR in DN format to asciiz string, placing result into \fIname\fR buffer of size \fInamesiz\fR. Maximum length of asciiz representation of domain name is \fBDNS_MAXNAME\fR (1024) bytes. Root domain is represented as empty string. Return length of the resulting name (including terminating character, i.e. strlen(name)+1) on success, 0 if the \fIname\fR buffer is too small, or negative value if \fIdn\fR is invalid (last case should never happen since all routines in this library which produce domain names ensure the DNs generated are valid). .RE .PP .nf const char *\fBdns_dntosp\fR(const unsigned char *\fIdn\fR) .fi .RS convert domain name \fIdn\fR in DN format to asciiz string using static buffer. Return the resulting asciiz string on success or NULL on failure. Note since this routine uses static buffer, it is not thread-safe. .RE .PP .nf unsigned \fBdns_dntop_size\fR(const unsigned char *\fIdn\fR) .fi .RS return the buffer size needed to convert the \fIdn\fR domain name in DN format to asciiz string, for \fBdns_dntop\fR(). The routine return either the size of buffer required, including the trailing zero byte, or 0 if \fIdn\fR is invalid. .RE .SS "Working with DNS Packets" .PP The following routines are provided to encode and decode DNS on-wire packets. This is low-level interface. .PP DNS response codes (returned by \fBdns_rcode\fR() routine) are defined as constants prefixed with \fBDNS_R_\fR. See udns.h header file for the complete list. In particular, constants \fBDNS_R_NOERROR\fR (0), \fBDNS_R_SERVFAIL\fR, \fBDNS_R_NXDOMAIN\fR may be of interest to an application. .PP .nf unsigned \fBdns_get16\fR(const unsigned char *\fIp\fR) unsigned \fBdns_get32\fR(const unsigned char *\fIp\fR) .fi .RS helper routines, convert 16-bit or 32-bit integer in on-wire format pointed to by \fIp\fR to unsigned. .RE .PP .nf unsigned char *\fBdns_put16\fR(unsigned char *\fId\fR, unsigned \fIn\fR) unsigned char *\fBdns_put32\fR(unsigned char *\fId\fR, unsigned \fIn\fR) .fi .RS helper routine, convert unsigned 16-bit or 32-bit integer \fIn\fR to on-wire format to buffer pointed to by \fId\fR, return \fId\fR+2 or \fId\fR+4. .RE .PP .nf \fBDNS_HSIZE\fR (12) .fi .RS defines size of DNS header. Data section in the DNS packet immediately follows the header. In the header, there are query identifier (id), various flags and codes, and number of resource records in various data sections. See udns.h header file for complete list of DNS header definitions. .RE .PP .nf unsigned \fBdns_qid\fR(const unsigned char *\fIpkt\fR) int \fBdns_rd\fR(const unsigned char *\fIpkt\fR) int \fBdns_tc\fR(const unsigned char *\fIpkt\fR) int \fBdns_aa\fR(const unsigned char *\fIpkt\fR) int \fBdns_qr\fR(const unsigned char *\fIpkt\fR) int \fBdns_ra\fR(const unsigned char *\fIpkt\fR) unsigned \fBdns_opcode\fR(const unsigned char *\fIpkt\fR) unsigned \fBdns_rcode\fR(const unsigned char *\fIpkt\fR) unsigned \fBdns_numqd\fR(const unsigned char *\fIpkt\fR) unsigned \fBdns_numan\fR(const unsigned char *\fIpkt\fR) unsigned \fBdns_numns\fR(const unsigned char *\fIpkt\fR) unsigned \fBdns_numar\fR(const unsigned char *\fIpkt\fR) const unsigned char *\fBdns_payload\fR(const unsigned char *\fIpkt\fR) .fi .RS return various parts from the DNS packet header \fIpkt\fR: query identifier (qid), recursion desired (rd) flag, truncation occurred (tc) flag, authoritative answer (aa) flag, query response (qr) flag, recursion available (ra) flag, operation code (opcode), result code (rcode), number of entries in question section (numqd), number of answers (numan), number of authority records (numns), number of additional records (numar), and the pointer to the packet data (payload). .RE .PP .nf int \fBdns_getdn\fR(\fIpkt\fR, \fIcurp\fR, \fIpkte\fR, \fIdn\fR, \fIdnsiz\fR) const unsigned char *\fBdns_skipdn\fR(\fIcur\fR, \fIpkte\fR) const unsigned char *\fIpkt\fR, *\fIpkte\fR, **\fIcurp\fR, *\fIcur\fR; unsigned char *\fIdn\fR; unsigned \fIdnsiz\fR; .fi .RS \fBdns_getdn\fR() extract DN from DNS packet \fIpkt\fR which ends before \fIpkte\fR starting at position *\fIcurp\fR into buffer pointed to by \fIdn\fR of size \fIdnsiz\fR. Upon successeful completion, *\fIcurp\fR will point to the next byte in the packet after the extracted domain name. It return positive number (length of the DN if \fIdn\fR) upon successeful completion, negative value on error (when the packet contains invalid data), or zero if the \fIdnsiz\fR is too small (maximum length of a domain name is \fBDNS_MAXDN\fR). \fBdns_skipdn\fR() return pointer to the next byte in DNS packet which ends up before \fIpkte\fR after a domain name which starts at the \fIcur\fP byte, or NULL if the packet is invalid. \fBdns_skipdn\fR() is more or less equivalent to what \fBdns_getdn\fR() does, except it does not actually extract the domain name in question, and uses simpler interface. .RE .PP .nf struct \fBdns_rr\fR { unsigned char \fBdnsrr_dn\fR[DNS_MAXDN]; /* the RR DN name */ enum dns_class \fBdnsrr_cls\fR; /* class of the RR */ enum dns_type \fBdnsrr_typ\fR; /* type of the RR */ unsigned \fBdnsrr_ttl\fR; /* TTL value */ unsigned \fBdnsrr_dsz\fR; /* size of data in bytes */ const unsigned char *\fBdnsrr_dptr\fR; /* pointer to the first data byte */ const unsigned char *\fBdnsrr_dend\fR; /* next byte after RR */ }; .fi .RS The \fBdns_rr\fR structure is used to hold information about single DNS Resource Record (RR) in an easy to use form. .RE .PP .nf struct \fBdns_parse\fR { const unsigned char *\fBdnsp_pkt\fR; /* pointer to the packet being parsed */ const unsigned char *\fBdnsp_end\fR; /* end of the packet pointer */ const unsigned char *\fBdnsp_cur\fR; /* current packet position */ const unsigned char *\fBdnsp_ans\fR; /* pointer to the answer section */ int \fBdnsp_rrl\fR; /* number of RRs left */ int \fBdnsp_nrr\fR; /* number of relevant RRs seen so far */ unsigned \fBdnsp_ttl\fR; /* TTL value so far */ const unsigned char *\fBdnsp_qdn\fR; /* the domain of interest or NULL */ enum dns_class \fBdnsp_qcls\fR; /* class of interest or 0 for any */ enum dns_type \fBdnsp_qtyp\fR; /* type of interest or 0 for any */ unsigned char \fBdnsp_dnbuf\fR[DNS_MAXDN]; /* domain name buffer */ }; .fi .RS The \fBdns_parse\fR structure is used to parse DNS reply packet. It holds information about the packet being parsed (dnsp_pkt, dnsp_end and dnsp_cur fields), number of RRs in the current section left to do, and the information about specific RR which we're looking for (dnsp_qdn, dnsp_qcls and dnsp_qtyp fields). .RE .PP .nf int \fBdns_initparse\fR(struct dns_parse *\fIp\fR, const unsigned char *\fIqdn\fR, const unsigned char *\fIpkt\fR, const unsigned char *\fIcur\fR, const unsigned char *\fIend\fR) .fi .RS initializes the RR parsing structure \fIp\fR. Arguments \fIpkt\fR, \fIcur\fR and \fIend\fR should describe the received packet: \fIpkt\fR is the start of the packet, \fIend\fR points to the next byte after the end of the packet, and \fIcur\fR points past the query DN in query section (to query class+type information). And \fIqdn\fR points to the query DN. This is the arguments passed to \fBdns_parse_fn\fR() routine. \fBdns_initparse\fR() initializes \fBdnsp_pkt\fR, \fBdnsp_end\fR and \fBdnsp_qdn\fR fields to the corresponding arguments, extracts and initializes \fBdnsp_qcls\fR and \fBdnsp_qtyp\fR fields to the values found at \fIcur\fR pointer, initializes \fBdnsp_cur\fR and \fBdnsp_ans\fR fields to be \fIcur\fR+4 (to the start of answer section), and initializes \fBdnsp_rrl\fR field to be number of entries in answer section. \fBdnsp_ttl\fR will be set to max TTL value, 0xffffffff, and \fBdnsp_nrr\fR to 0. .RE .PP .nf int \fBdns_nextrr\fR(struct dns_parse *\fIp\fR, struct dns_rr *\fIrr\fR); .fi .RS searches for next RR in the packet based on the criteria provided in the \fIp\fR structure, filling in the \fIrr\fR structure and advancing \fIp\fR->\fBdnsp_cur\fR to the next RR in the packet. RR selection is based on dnsp_qdn, dnsp_qcls and dnsp_qtyp fields in the dns_parse structure. Any (or all) of the 3 fields may be 0, which means any actual value from the packet is acceptable. In case the field isn't 0 (or NULL for dnsp_qdn), only RRs with corresponding characteristics are acceptable. Additionally, when dnsp_qdn is non-NULL, \fBdns_nextrr\fR() performs automatic CNAME expansion. Routine will return positive value on success, 0 in case it reached the end of current section in the packet (\fIp\fR->\fBdnsp_rrl\fR is zero), or negative value if next RR can not be decoded (packet format is invalid). The routine updates \fIp\fR->\fBdnsp_qdn\fR automatically when this field is non-NULL and it encounters appropriate CNAME RRs (saving CNAME target in \fIp\fR->\fBdnsp_dnbuf\fR), so after end of the process, \fIp\fR->\fBdnsp_qdn\fR will point to canonical name of the domain in question. The routine updates \fIp\fR->\fBdnsp_ttl\fR value to be the minimum TTL of all RRs found. .RE .PP .nf void \fBdns_rewind\fR(struct dns_parse *\fIp\fR, const unsigned char *\fIqdn\fR) .fi .RS this routine "rewinds" the packet parse state structure to be at the same state as after a call to \fBdns_initparse\fR(), i.e. reposition the parse structure \fIp\fR to the start of answer section and initialize \fIp\fR->\fBdnsp_rrl\fR to the number of entries in answer section. .RE .PP .nf int \fBdns_stdrr_size\fR(const struct dns_parse *\fIp\fR); .fi .RS return size to hold standard RRset structure information, as shown in \fBdns_rr_null\fR structure (for the query and canonical names). Used to calculate amount of memory to allocate for common part of type-specific RR structures in parsing routines. .RE .PP .nf void *\fBdns_stdrr_finish\fR(struct dns_rr_null *\fIret\fR, char *\fIcp\fR, const struct dns_parse *\fIp\fR); .fi .RS initializes standard RRset fields in \fIret\fR structure using buffer pointed to by \fIcp\fR, which should have at least as many bytes as \fBdns_stdrr_size\fR(\fIp\fR) returned. Used to finalize common part of type-specific RR structures in parsing routines. .RE .PP See library source for usage examples of all the above low-level routines, especially source of the parsing routines. .SS "Auxilary Routines" .PP .nf int \fBdns_pton\fR(int \fIaf\fR, const char *\fIsrc\fR, void *\fIdst\fR); .fi .RS privides functionality similar to standard \fBinet_pton\fR() routine, to convert printable representation of an IP address of family \fIaf\fR (either \fBAF_INET\fR or \fBAF_INET6\fR) pointed to by \fIsrc\fR into binary form suitable for socket addresses and transmission over network, in buffer pointed to by \fIdst\fR. The destination buffer should be of size 4 for \fBAF_INET\fR family or 16 for \fBAF_INET6\fR. The return value is positive on success, 0 if \fIsrc\fR is not a valid text representation of an address of family \fIaf\fR, or negative if the given address family is not supported. .RE .PP .nf const char *\fBdns_ntop\fR(int \fIaf\fR, const void *\fIsrc\fR, char *\fIdst\fR, int \fIdstsize\fR) .fi .RS privides functionality similar to standard \fBinet_ntop\fR() routine, to convert binary representation of an IP address of family \fIaf\fR (either \fBAF_INET\fR or \fBAF_INET6\fR) pointed to by \fIsrc\fR (either 4 or 16 bytes) into printable form in buffer in buffer pointed to by \fIdst\fR of size \fIdstsize\fR. The destination buffer should be at least of size 16 bytes for \fBAF_INET\fR family or 46 bytes for \fBAF_INET6\fR. The return value is either \fIdst\fR, or NULL pointer if \fIdstsize\fR is too small to hold this address or if the given address family is not supported. .RE .SH AUTHOR .PP The \fBudns\fR library has been written by Michael Tokarev, mjt+udns@tls.msk.ru. .SH VERSION .PP This manual page corresponds to udns version 0.6, released Jul-2024. udns-0.6/dnsget.10000644000175000017500000001165114573071715012062 0ustar mjtmjt.\" dnsget.1: dnsget manpage .\" .\" Copyright (C) 2005-2014 Michael Tokarev .\" This file is part of UDNS library, an async DNS stub resolver. .\" .\" This library is free software; you can redistribute it and/or .\" modify it under the terms of the GNU Lesser General Public .\" License as published by the Free Software Foundation; either .\" version 2.1 of the License, or (at your option) any later version. .\" .\" This library is distributed in the hope that it will be useful, .\" but WITHOUT ANY WARRANTY; without even the implied warranty of .\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU .\" Lesser General Public License for more details. .\" .\" You should have received a copy of the GNU Lesser General Public .\" License along with this library, in file named COPYING.LGPL; if not, .\" write to the Free Software Foundation, Inc., 59 Temple Place, .\" Suite 330, Boston, MA 02111-1307 USA .TH dnsget 1 "Jan 2014" "User Utilities" .SH NAME dnsget \- DNS lookup utility .SH SYNOPSYS .B dnsget .RB [\| \-v \||\| \-q \|] .RB [\| \-c .IR class \|] .RB [\| \-t .IR type \|] .RB [\| \-o .IR opt , opt ,...] .IR name \|.\|.\|. .SH DESCRIPTION .B dnsget is a simple command-line to perform DNS lookups, similar to .BR host (1) and .BR dig (1). It is useable for both interactive/debugging scenarious and in scripts. The program is implemented using .BR udns (3) library. .PP By default, .B dnsget produces a human-readable output, similar to .RS .nf alias.example.com. CNAME www.example.com. www.example.com. A 192.168.1.1 www.example.com. MX 10 mx.example.com. .fi .RE which is just sufficient to see how a given name resolves. Output format is controllable with .B \-v and .B \-q options -- the former increases verbosity level up to printing the whole DNS contents of all packets sent and received, which is suitable for debugging DNS problems, while the latter reduces the level, making output more quiet, up to bare result with no error messages, which is good for scripts. .SH OPTIONS The following options are recognized by .BR dnsget : .TP .B \-v produce more detailed output. More .BR \-v 's means more details will be produced. With single .BR \-v , dnsget will print contents of all received DNS packets (in a readable format), while with .BR \-vv , it will output all outgoing DNS packets too. .TP .B \-q the opposite for \fB\-v\fR -- produce less detailed output. With single .BR \-q , dnsget will only show (decoded) data from final DNS resource records (RR), while .B \-qq also suppresses error messages. .TP \fB\-t \fItype\fR request record(s) of the given type \fItype\fR. By default, .B dnsget will ask for IPv4 address (A) record, or for PTR record if the argument in question is an IPv4 or IPv6 address. Recognized types include A, AAAA, MX, TXT, CNAME, PTR, NS, SOA, ANY and others. .TP \fB\-c \fIclass\fR request DNS record(s) of the given class \fIclass\fR. By default .B dnsget uses IN class. Valid classes include IN, CH, HS, ANY. .TP .B \-a (compatibility option). Equivalent to setting query type to .B ANY and increasing verbosity level .RB ( \-v ). .TP .B \-C (planned) .TP .B \-x (planned) .TP \fB\-o \fIopt\fR,\fIopt\fR,... (may be specified several times). Set resolver options (in a form \fIoption\fR:\fIvalue\fR) as if they were set in .RB $ RES_OPTIONS environment variable, or set query flags: .RS .TP \fBtimeout\fR:\fIsec\fR Set initial query timeout to \fIsec\fR. .TP \fBattempts\fR:\fInum\fR (re)try every query \fInum\fR times before failing. .TP \fBudpbuf\fR:\fIbytes\fR set DNS UDP buffer size to \fIbytes\fR bytes. Valid values are from 512 to 65535. If \fIbytes\fR is greather than 512, EDNS0 (RFC 2671) extensions will be used. .TP \fBport\fR:\fInum\fR Use given UDP port number \fInum\fR instead of the default port 53 (domain). .TP \fBaa\fR set AA (auth only) query bit. .TP \fBnord\fR do not set RD (recursion desired) query bit (set by default). .TP \fBdnssec\fR or \fBdo\fR set DNSSEC OK (DO) query flag (\fBdnsget\fR does not verify DNSSEC signatures, only displays them; this is set in EDNS RR). .TP \fBcd\fR set CD (checking disabled) query bit. .RE .TP \fB\-n \fInameserver\fR Use the given nameserver(s) (may be specified more than once) instead of the default. Using this option has the same same effect as .RB $ NSCACHEIP or .RB $ NAMESERVERS environment variables, with the only difference that only IPv4 addresses are recognized for now, and it is possible to specify names (which will be resolved using default settings) instead of IP addresses. .TP .B \-h print short help and exit. .SH "RETURN VALUE" When all names where resovled successefully, .B dnsget exits with zero exit status. If at least one name was not found, .B dnsget will exit with return code 100. If some other error occurred during name resolution, it will exit with code 99. In case of usage or initialization error, .B dnsget will return 1. .SH "SEE ALSO" .BR host (1) .BR dig (1) .BR resolv.conf (5) .BR udns (3). udns-0.6/rblcheck.10000644000175000017500000000743414573071715012357 0ustar mjtmjt.\" rblcheck.1 .\" rblckeck manpage .\" .\" Copyright (C) 2005 Michael Tokarev .\" This file is part of UDNS library, an async DNS stub resolver. .\" .\" This library is free software; you can redistribute it and/or .\" modify it under the terms of the GNU Lesser General Public .\" License as published by the Free Software Foundation; either .\" version 2.1 of the License, or (at your option) any later version. .\" .\" This library is distributed in the hope that it will be useful, .\" but WITHOUT ANY WARRANTY; without even the implied warranty of .\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU .\" Lesser General Public License for more details. .\" .\" You should have received a copy of the GNU Lesser General Public .\" License along with this library, in file named COPYING.LGPL; if not, .\" write to the Free Software Foundation, Inc., 59 Temple Place, .\" Suite 330, Boston, MA 02111-1307 USA .TH rblckeck 1 "Apr 2005" "User Utilities" .SH NAME rblckeck \- DNSBL lookup utility .SH SYNOPSYS .B rblcheck .RB [\| \-s .IR zone \|] .RB [\| \-S .IR zone\-file \|] .RB [\| \-c \|] .RB [\| \-tmvq \|] .RB [\| \-n .IR nsaddr \|] .IR address \|.\|.\|. .SH DESCRIPTION .B rblcheck is a simple command-line to perform DNSBL (DNS-based blocklists) lookups. For every IP address (or a name, in which case it will be resolved to an address first), the utility verifies whenever it is listed in a (list of) DNS blocklists specified with .B \-s or .B \-S options, optionally obtains text associated with the listing (usually it is either some description about the reason of the listing or an URL referring to such a description), and displays results on standard output. .PP The program is implemented on top of .BR udns (3) library. .SH OPTIONS The following options are recognized by .BR rblcheck : .TP .B \-s \fIzone\fR add the given \fIzone\fR DNSBL name to the list of active zones. .TP .B \-S \fIzone-file\fR add list of zones from the named \fIzone-file\fR to the list of active zones (the file specifies one zone as the first word on a line, empty lines and lines starting with `#' character are ignored). .TP .B \-c reset active zone list. .TP .B \-v be more verbose, produce more detailed output. .TP .B \-q the opposite for \fB\-v\fR -- produce less detailed output. .TP .B \-t obtain text for listed addresses. .TP .B \-n \fInsaddr\fR Use the given nameserver (given as IPv4 or IPv6 address) instead of the default. The same effect may be achieved by setting $NSCACHEIP environment variable. .TP .B \-m stop after first hit, ie after the first address which is found to be listed. .TP .B \-h print short help and exit. .PP If no .BR \-s , .BR \-S and .B \-c options are given, .B rblcheck will try to obtain list of zones using $RBLCHECK_ZONES environment variable, or ~/.rblcheckrc, or /etc/rblckechrc files, in that order. If no zones are found, it will exit unsuccessefully. .SH "RETURN VALUE" When no addresses given are listed and no errors occurred, .B rblcheck exits with code 0. If at least one address is listed, .B rblcheck returns 100. In case of DNS errors, .B rblcheck returns 2. .SH ENVIRONMENT .TP .B $RBLCHECK_ZONES if no .BR \-s , .B \-S or .B \-c option is given, .B rblcheck tries this variable to obtain list of DNSBL zones to check against. .SH FILES .TP $HOME/.rblcheckrc and /etc/rblcheckrc if no .BR \-s , .B \-S or .B \-c option is given, and no $RBLCHECK_ZONES environment variable is set, .B rblcheck will try the two files (the first one that exists) to obtain list of DNSBL zones to check against. Each line specifies one zone (only first word in each line is used). Empty lines and lines starting with `#' character are ignored. .SH "SEE ALSO" .BR dnsget (1) .BR resolv.conf (5) .BR udns (3). .SH AUTHOR This program and manual pages are written by Michael Tokarev. udns-0.6/udns_dn.c0000644000175000017500000002324211604616213012277 0ustar mjtmjt/* udns_dn.c domain names manipulation routines Copyright (C) 2005 Michael Tokarev This file is part of UDNS library, an async DNS stub resolver. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library, in file named COPYING.LGPL; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include #include "udns.h" unsigned dns_dnlen(dnscc_t *dn) { register dnscc_t *d = dn; while(*d) d += 1 + *d; return (unsigned)(d - dn) + 1; } unsigned dns_dnlabels(register dnscc_t *dn) { register unsigned l = 0; while(*dn) ++l, dn += 1 + *dn; return l; } unsigned dns_dnequal(register dnscc_t *dn1, register dnscc_t *dn2) { register unsigned c; dnscc_t *dn = dn1; for(;;) { if ((c = *dn1++) != *dn2++) return 0; if (!c) return (unsigned)(dn1 - dn); while(c--) { if (DNS_DNLC(*dn1) != DNS_DNLC(*dn2)) return 0; ++dn1; ++dn2; } } } unsigned dns_dntodn(dnscc_t *sdn, dnsc_t *ddn, unsigned ddnsiz) { unsigned sdnlen = dns_dnlen(sdn); if (ddnsiz < sdnlen) return 0; memcpy(ddn, sdn, sdnlen); return sdnlen; } int dns_ptodn(const char *name, unsigned namelen, dnsc_t *dn, unsigned dnsiz, int *isabs) { dnsc_t *dp; /* current position in dn (len byte first) */ dnsc_t *const de /* end of dn: last byte that can be filled up */ = dn + (dnsiz >= DNS_MAXDN ? DNS_MAXDN : dnsiz) - 1; dnscc_t *np = (dnscc_t *)name; dnscc_t *ne = np + (namelen ? namelen : strlen((char*)np)); dnsc_t *llab; /* start of last label (llab[-1] will be length) */ unsigned c; /* next input character, or length of last label */ if (!dnsiz) return 0; dp = llab = dn + 1; while(np < ne) { if (*np == '.') { /* label delimiter */ c = dp - llab; /* length of the label */ if (!c) { /* empty label */ if (np == (dnscc_t *)name && np + 1 == ne) { /* special case for root dn, aka `.' */ ++np; break; } return -1; /* zero label */ } if (c > DNS_MAXLABEL) return -1; /* label too long */ llab[-1] = (dnsc_t)c; /* update len of last label */ llab = ++dp; /* start new label, llab[-1] will be len of it */ ++np; continue; } /* check whenever we may put out one more byte */ if (dp >= de) /* too long? */ return dnsiz >= DNS_MAXDN ? -1 : 0; if (*np != '\\') { /* non-escape, simple case */ *dp++ = *np++; continue; } /* handle \-style escape */ /* note that traditionally, domain names (gethostbyname etc) * used decimal \dd notation, not octal \ooo (RFC1035), so * we're following this tradition here. */ if (++np == ne) return -1; /* bad escape */ else if (*np >= '0' && *np <= '9') { /* decimal number */ /* we allow not only exactly 3 digits as per RFC1035, * but also 2 or 1, for better usability. */ c = *np++ - '0'; if (np < ne && *np >= '0' && *np <= '9') { /* 2digits */ c = c * 10 + *np++ - '0'; if (np < ne && *np >= '0' && *np <= '9') { c = c * 10 + *np++ - '0'; if (c > 255) return -1; /* bad escape */ } } } else c = *np++; *dp++ = (dnsc_t)c; /* place next out byte */ } if ((c = dp - llab) > DNS_MAXLABEL) return -1; /* label too long */ if ((llab[-1] = (dnsc_t)c) != 0) { *dp++ = 0; if (isabs) *isabs = 0; } else if (isabs) *isabs = 1; return dp - dn; } dnscc_t dns_inaddr_arpa_dn[14] = "\07in-addr\04arpa"; dnsc_t * dns_a4todn_(const struct in_addr *addr, dnsc_t *dn, dnsc_t *dne) { const unsigned char *s = ((const unsigned char *)addr) + 4; while(s > (const unsigned char *)addr) { unsigned n = *--s; dnsc_t *p = dn + 1; if (n > 99) { if (p + 2 > dne) return 0; *p++ = n / 100 + '0'; *p++ = (n % 100 / 10) + '0'; *p = n % 10 + '0'; } else if (n > 9) { if (p + 1 > dne) return 0; *p++ = n / 10 + '0'; *p = n % 10 + '0'; } else { if (p > dne) return 0; *p = n + '0'; } *dn = p - dn; dn = p + 1; } return dn; } int dns_a4todn(const struct in_addr *addr, dnscc_t *tdn, dnsc_t *dn, unsigned dnsiz) { dnsc_t *dne = dn + (dnsiz > DNS_MAXDN ? DNS_MAXDN : dnsiz); dnsc_t *p; unsigned l; p = dns_a4todn_(addr, dn, dne); if (!p) return 0; if (!tdn) tdn = dns_inaddr_arpa_dn; l = dns_dnlen(tdn); if (p + l > dne) return dnsiz >= DNS_MAXDN ? -1 : 0; memcpy(p, tdn, l); return (p + l) - dn; } int dns_a4ptodn(const struct in_addr *addr, const char *tname, dnsc_t *dn, unsigned dnsiz) { dnsc_t *p; int r; if (!tname) return dns_a4todn(addr, NULL, dn, dnsiz); p = dns_a4todn_(addr, dn, dn + dnsiz); if (!p) return 0; r = dns_sptodn(tname, p, dnsiz - (p - dn)); return r != 0 ? r : dnsiz >= DNS_MAXDN ? -1 : 0; } dnscc_t dns_ip6_arpa_dn[10] = "\03ip6\04arpa"; dnsc_t * dns_a6todn_(const struct in6_addr *addr, dnsc_t *dn, dnsc_t *dne) { const unsigned char *s = ((const unsigned char *)addr) + 16; if (dn + 64 > dne) return 0; while(s > (const unsigned char *)addr) { unsigned n = *--s & 0x0f; *dn++ = 1; *dn++ = n > 9 ? n + 'a' - 10 : n + '0'; *dn++ = 1; n = *s >> 4; *dn++ = n > 9 ? n + 'a' - 10 : n + '0'; } return dn; } int dns_a6todn(const struct in6_addr *addr, dnscc_t *tdn, dnsc_t *dn, unsigned dnsiz) { dnsc_t *dne = dn + (dnsiz > DNS_MAXDN ? DNS_MAXDN : dnsiz); dnsc_t *p; unsigned l; p = dns_a6todn_(addr, dn, dne); if (!p) return 0; if (!tdn) tdn = dns_ip6_arpa_dn; l = dns_dnlen(tdn); if (p + l > dne) return dnsiz >= DNS_MAXDN ? -1 : 0; memcpy(p, tdn, l); return (p + l) - dn; } int dns_a6ptodn(const struct in6_addr *addr, const char *tname, dnsc_t *dn, unsigned dnsiz) { dnsc_t *p; int r; if (!tname) return dns_a6todn(addr, NULL, dn, dnsiz); p = dns_a6todn_(addr, dn, dn + dnsiz); if (!p) return 0; r = dns_sptodn(tname, p, dnsiz - (p - dn)); return r != 0 ? r : dnsiz >= DNS_MAXDN ? -1 : 0; } /* return size of buffer required to convert the dn into asciiz string. * Keep in sync with dns_dntop() below. */ unsigned dns_dntop_size(dnscc_t *dn) { unsigned size = 0; /* the size reqd */ dnscc_t *le; /* label end */ while(*dn) { /* *dn is the length of the next label, non-zero */ if (size) ++size; /* for the dot */ le = dn + *dn + 1; ++dn; do { switch(*dn) { case '.': case '\\': /* Special modifiers in zone files. */ case '"': case ';': case '@': case '$': size += 2; break; default: if (*dn <= 0x20 || *dn >= 0x7f) /* \ddd decimal notation */ size += 4; else size += 1; } } while(++dn < le); } size += 1; /* zero byte at the end - string terminator */ return size > DNS_MAXNAME ? 0 : size; } /* Convert the dn into asciiz string. * Keep in sync with dns_dntop_size() above. */ int dns_dntop(dnscc_t *dn, char *name, unsigned namesiz) { char *np = name; /* current name ptr */ char *const ne = name + namesiz; /* end of name */ dnscc_t *le; /* label end */ while(*dn) { /* *dn is the length of the next label, non-zero */ if (np != name) { if (np >= ne) goto toolong; *np++ = '.'; } le = dn + *dn + 1; ++dn; do { switch(*dn) { case '.': case '\\': /* Special modifiers in zone files. */ case '"': case ';': case '@': case '$': if (np + 2 > ne) goto toolong; *np++ = '\\'; *np++ = *dn; break; default: if (*dn <= 0x20 || *dn >= 0x7f) { /* \ddd decimal notation */ if (np + 4 >= ne) goto toolong; *np++ = '\\'; *np++ = '0' + (*dn / 100); *np++ = '0' + ((*dn % 100) / 10); *np++ = '0' + (*dn % 10); } else { if (np >= ne) goto toolong; *np++ = *dn; } } } while(++dn < le); } if (np >= ne) goto toolong; *np++ = '\0'; return np - name; toolong: return namesiz >= DNS_MAXNAME ? -1 : 0; } #ifdef TEST #include #include int main(int argc, char **argv) { int i; int sz; dnsc_t dn[DNS_MAXDN+10]; dnsc_t *dl, *dp; int isabs; sz = (argc > 1) ? atoi(argv[1]) : 0; for(i = 2; i < argc; ++i) { int r = dns_ptodn(argv[i], 0, dn, sz, &isabs); printf("%s: ", argv[i]); if (r < 0) printf("error\n"); else if (!r) printf("buffer too small\n"); else { printf("len=%d dnlen=%d size=%d name:", r, dns_dnlen(dn), dns_dntop_size(dn)); dl = dn; while(*dl) { printf(" %d=", *dl); dp = dl + 1; dl = dp + *dl; while(dp < dl) { if (*dp <= ' ' || *dp >= 0x7f) printf("\\%03d", *dp); else if (*dp == '.' || *dp == '\\') printf("\\%c", *dp); else putchar(*dp); ++dp; } } if (isabs) putchar('.'); putchar('\n'); } } return 0; } #endif /* TEST */ udns-0.6/udns_dntosp.c0000644000175000017500000000214511604616221013203 0ustar mjtmjt/* udns_dntosp.c dns_dntosp() = convert DN to asciiz string using static buffer Copyright (C) 2005 Michael Tokarev This file is part of UDNS library, an async DNS stub resolver. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library, in file named COPYING.LGPL; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include "udns.h" static char name[DNS_MAXNAME]; const char *dns_dntosp(dnscc_t *dn) { return dns_dntop(dn, name, sizeof(name)) > 0 ? name : 0; } udns-0.6/udns_parse.c0000644000175000017500000001255111604616266013021 0ustar mjtmjt/* udns_parse.c raw DNS packet parsing routines Copyright (C) 2005 Michael Tokarev This file is part of UDNS library, an async DNS stub resolver. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library, in file named COPYING.LGPL; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include #include #include "udns.h" dnscc_t *dns_skipdn(dnscc_t *cur, dnscc_t *end) { unsigned c; for(;;) { if (cur >= end) return NULL; c = *cur++; if (!c) return cur; if (c & 192) /* jump */ return cur + 1 >= end ? NULL : cur + 1; cur += c; } } int dns_getdn(dnscc_t *pkt, dnscc_t **cur, dnscc_t *end, register dnsc_t *dn, unsigned dnsiz) { unsigned c; dnscc_t *pp = *cur; /* current packet pointer */ dnsc_t *dp = dn; /* current dn pointer */ dnsc_t *const de /* end of the DN dest */ = dn + (dnsiz < DNS_MAXDN ? dnsiz : DNS_MAXDN); dnscc_t *jump = NULL; /* ptr after first jump if any */ unsigned loop = 100; /* jump loop counter */ for(;;) { /* loop by labels */ if (pp >= end) /* reached end of packet? */ return -1; c = *pp++; /* length of the label */ if (!c) { /* empty label: terminate */ if (dn >= de) /* can't fit terminator */ goto noroom; *dp++ = 0; /* return next pos: either after the first jump or current */ *cur = jump ? jump : pp; return dp - dn; } if (c & 192) { /* jump */ if (pp >= end) /* eop instead of jump pos */ return -1; if (!jump) jump = pp + 1; /* remember first jump */ else if (!--loop) return -1; /* too many jumps */ c = ((c & ~192) << 8) | *pp; /* new pos */ if (c < DNS_HSIZE) /* don't allow jump into the header */ return -1; pp = pkt + c; continue; } if (c > DNS_MAXLABEL) /* too long label? */ return -1; if (pp + c > end) /* label does not fit in packet? */ return -1; if (dp + c + 1 > de) /* if enouth room for the label */ goto noroom; *dp++ = c; /* label length */ memcpy(dp, pp, c); /* and the label itself */ dp += c; pp += c; /* advance to the next label */ } noroom: return dnsiz < DNS_MAXDN ? 0 : -1; } void dns_rewind(struct dns_parse *p, dnscc_t *qdn) { p->dnsp_qdn = qdn; p->dnsp_cur = p->dnsp_ans; p->dnsp_rrl = dns_numan(p->dnsp_pkt); p->dnsp_ttl = 0xffffffffu; p->dnsp_nrr = 0; } void dns_initparse(struct dns_parse *p, dnscc_t *qdn, dnscc_t *pkt, dnscc_t *cur, dnscc_t *end) { p->dnsp_pkt = pkt; p->dnsp_end = end; p->dnsp_rrl = dns_numan(pkt); p->dnsp_qdn = qdn; assert(cur + 4 <= end); if ((p->dnsp_qtyp = dns_get16(cur+0)) == DNS_T_ANY) p->dnsp_qtyp = 0; if ((p->dnsp_qcls = dns_get16(cur+2)) == DNS_C_ANY) p->dnsp_qcls = 0; p->dnsp_cur = p->dnsp_ans = cur + 4; p->dnsp_ttl = 0xffffffffu; p->dnsp_nrr = 0; } int dns_nextrr(struct dns_parse *p, struct dns_rr *rr) { dnscc_t *cur = p->dnsp_cur; while(p->dnsp_rrl > 0) { --p->dnsp_rrl; if (dns_getdn(p->dnsp_pkt, &cur, p->dnsp_end, rr->dnsrr_dn, sizeof(rr->dnsrr_dn)) <= 0) return -1; if (cur + 10 > p->dnsp_end) return -1; rr->dnsrr_typ = dns_get16(cur); rr->dnsrr_cls = dns_get16(cur+2); rr->dnsrr_ttl = dns_get32(cur+4); rr->dnsrr_dsz = dns_get16(cur+8); rr->dnsrr_dptr = cur = cur + 10; rr->dnsrr_dend = cur = cur + rr->dnsrr_dsz; if (cur > p->dnsp_end) return -1; if (p->dnsp_qdn && !dns_dnequal(p->dnsp_qdn, rr->dnsrr_dn)) continue; if ((!p->dnsp_qcls || p->dnsp_qcls == rr->dnsrr_cls) && (!p->dnsp_qtyp || p->dnsp_qtyp == rr->dnsrr_typ)) { p->dnsp_cur = cur; ++p->dnsp_nrr; if (p->dnsp_ttl > rr->dnsrr_ttl) p->dnsp_ttl = rr->dnsrr_ttl; return 1; } if (p->dnsp_qdn && rr->dnsrr_typ == DNS_T_CNAME && !p->dnsp_nrr) { if (dns_getdn(p->dnsp_pkt, &rr->dnsrr_dptr, p->dnsp_end, p->dnsp_dnbuf, sizeof(p->dnsp_dnbuf)) <= 0 || rr->dnsrr_dptr != rr->dnsrr_dend) return -1; p->dnsp_qdn = p->dnsp_dnbuf; if (p->dnsp_ttl > rr->dnsrr_ttl) p->dnsp_ttl = rr->dnsrr_ttl; } } p->dnsp_cur = cur; return 0; } int dns_stdrr_size(const struct dns_parse *p) { return dns_dntop_size(p->dnsp_qdn) + (p->dnsp_qdn == dns_payload(p->dnsp_pkt) ? 0 : dns_dntop_size(dns_payload(p->dnsp_pkt))); } void *dns_stdrr_finish(struct dns_rr_null *ret, char *cp, const struct dns_parse *p) { cp += dns_dntop(p->dnsp_qdn, (ret->dnsn_cname = cp), DNS_MAXNAME); if (p->dnsp_qdn == dns_payload(p->dnsp_pkt)) ret->dnsn_qname = ret->dnsn_cname; else dns_dntop(dns_payload(p->dnsp_pkt), (ret->dnsn_qname = cp), DNS_MAXNAME); ret->dnsn_ttl = p->dnsp_ttl; return ret; } udns-0.6/udns_resolver.c0000644000175000017500000012213514573071032013542 0ustar mjtmjt/* udns_resolver.c resolver stuff (main module) Copyright (C) 2005 Michael Tokarev This file is part of UDNS library, an async DNS stub resolver. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library, in file named COPYING.LGPL; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #ifdef HAVE_CONFIG_H # include "config.h" #endif #ifdef WINDOWS # include /* includes */ # include /* needed for struct in6_addr */ #else # include # include # include # include # include # include # ifdef HAVE_POLL # include # else # ifdef HAVE_SYS_SELECT_H # include # endif # endif # ifdef HAVE_TIMES # include # endif # define closesocket(sock) close(sock) #endif /* !WINDOWS */ #include #include #include #include #include #include #include "udns.h" #ifndef EAFNOSUPPORT # define EAFNOSUPPORT EINVAL #endif #ifndef MSG_DONTWAIT # define MSG_DONTWAIT 0 #endif struct dns_qlist { struct dns_query *head, *tail; }; struct dns_query { struct dns_query *dnsq_next; /* double-linked list */ struct dns_query *dnsq_prev; unsigned dnsq_origdnl0; /* original query DN len w/o last 0 */ unsigned dnsq_flags; /* control flags for this query */ unsigned dnsq_servi; /* index of next server to try */ unsigned dnsq_servwait; /* bitmask: servers left to wait */ unsigned dnsq_servskip; /* bitmask: servers to skip */ unsigned dnsq_servnEDNS0; /* bitmask: servers refusing EDNS0 */ unsigned dnsq_try; /* number of tries made so far */ dnscc_t *dnsq_nxtsrch; /* next search pointer @dnsc_srchbuf */ time_t dnsq_deadline; /* when current try will expire */ dns_parse_fn *dnsq_parse; /* parse: raw => application */ dns_query_fn *dnsq_cbck; /* the callback to call when done */ void *dnsq_cbdata; /* user data for the callback */ #ifndef NDEBUG struct dns_ctx *dnsq_ctx; /* the resolver context */ #endif /* char fields at the end to avoid padding */ dnsc_t dnsq_id[2]; /* query ID */ dnsc_t dnsq_typcls[4]; /* requested RR type+class */ dnsc_t dnsq_dn[DNS_MAXDN+DNS_DNPAD]; /* the query DN +alignment */ }; /* working with dns_query lists */ static __inline void qlist_init(struct dns_qlist *list) { list->head = list->tail = NULL; } static __inline void qlist_remove(struct dns_qlist *list, struct dns_query *q) { if (q->dnsq_prev) q->dnsq_prev->dnsq_next = q->dnsq_next; else list->head = q->dnsq_next; if (q->dnsq_next) q->dnsq_next->dnsq_prev = q->dnsq_prev; else list->tail = q->dnsq_prev; } static __inline void qlist_add_head(struct dns_qlist *list, struct dns_query *q) { q->dnsq_next = list->head; if (list->head) list->head->dnsq_prev = q; else list->tail = q; list->head = q; q->dnsq_prev = NULL; } static __inline void qlist_insert_after(struct dns_qlist *list, struct dns_query *q, struct dns_query *prev) { if ((q->dnsq_prev = prev) != NULL) { if ((q->dnsq_next = prev->dnsq_next) != NULL) q->dnsq_next->dnsq_prev = q; else list->tail = q; prev->dnsq_next = q; } else qlist_add_head(list, q); } union sockaddr_ns { struct sockaddr sa; struct sockaddr_in sin; #ifdef HAVE_IPv6 struct sockaddr_in6 sin6; #endif }; #define sin_eq(a,b) \ ((a).sin_port == (b).sin_port && \ (a).sin_addr.s_addr == (b).sin_addr.s_addr) #define sin6_eq(a,b) \ ((a).sin6_port == (b).sin6_port && \ memcmp(&(a).sin6_addr, &(b).sin6_addr, sizeof(struct in6_addr)) == 0) struct dns_ctx { /* resolver context */ /* settings */ unsigned dnsc_flags; /* various flags */ unsigned dnsc_timeout; /* timeout (base value) for queries */ unsigned dnsc_ntries; /* number of retries */ unsigned dnsc_ndots; /* ndots to assume absolute name */ unsigned dnsc_port; /* default port (DNS_PORT) */ unsigned dnsc_udpbuf; /* size of UDP buffer */ /* array of nameserver addresses */ union sockaddr_ns dnsc_serv[DNS_MAXSERV]; unsigned dnsc_nserv; /* number of nameservers */ unsigned dnsc_salen; /* length of socket addresses */ dnsc_t dnsc_srchbuf[1024]; /* buffer for searchlist */ dnsc_t *dnsc_srchend; /* current end of srchbuf */ dns_utm_fn *dnsc_utmfn; /* register/cancel timer events */ void *dnsc_utmctx; /* user timer context for utmfn() */ time_t dnsc_utmexp; /* when user timer expires */ dns_dbgfn *dnsc_udbgfn; /* debugging function */ /* dynamic data */ struct udns_jranctx dnsc_jran; /* random number generator state */ unsigned dnsc_nextid; /* next queue ID to use if !0 */ int dnsc_udpsock; /* UDP socket */ struct dns_qlist dnsc_qactive; /* active list sorted by deadline */ int dnsc_nactive; /* number entries in dnsc_qactive */ dnsc_t *dnsc_pbuf; /* packet buffer (udpbuf size) */ int dnsc_qstatus; /* last query status value */ }; static const struct { const char *name; enum dns_opt opt; unsigned offset; unsigned min, max; } dns_opts[] = { #define opt(name,opt,field,min,max) \ {name,opt,offsetof(struct dns_ctx,field),min,max} opt("retrans", DNS_OPT_TIMEOUT, dnsc_timeout, 1,300), opt("timeout", DNS_OPT_TIMEOUT, dnsc_timeout, 1,300), opt("retry", DNS_OPT_NTRIES, dnsc_ntries, 1,50), opt("attempts", DNS_OPT_NTRIES, dnsc_ntries, 1,50), opt("ndots", DNS_OPT_NDOTS, dnsc_ndots, 0,1000), opt("port", DNS_OPT_PORT, dnsc_port, 1,0xffff), opt("udpbuf", DNS_OPT_UDPSIZE, dnsc_udpbuf, DNS_MAXPACKET,65536), #undef opt }; #define dns_ctxopt(ctx,idx) (*((unsigned*)(((char*)ctx)+dns_opts[idx].offset))) #define ISSPACE(x) (x == ' ' || x == '\t' || x == '\r' || x == '\n') struct dns_ctx dns_defctx; #define SETCTX(ctx) if (!ctx) ctx = &dns_defctx #define SETCTXINITED(ctx) SETCTX(ctx); assert(CTXINITED(ctx)) #define CTXINITED(ctx) (ctx->dnsc_flags & DNS_INITED) #define SETCTXFRESH(ctx) SETCTXINITED(ctx); assert(!CTXOPEN(ctx)) #define SETCTXINACTIVE(ctx) \ SETCTXINITED(ctx); assert(!ctx->dnsc_nactive) #define SETCTXOPEN(ctx) SETCTXINITED(ctx); assert(CTXOPEN(ctx)) #define CTXOPEN(ctx) (ctx->dnsc_udpsock >= 0) #if defined(NDEBUG) || !defined(DEBUG) #define dns_assert_ctx(ctx) #else static void dns_assert_ctx(const struct dns_ctx *ctx) { int nactive = 0; const struct dns_query *q; for(q = ctx->dnsc_qactive.head; q; q = q->dnsq_next) { assert(q->dnsq_ctx == ctx); assert(q == (q->dnsq_next ? q->dnsq_next->dnsq_prev : ctx->dnsc_qactive.tail)); assert(q == (q->dnsq_prev ? q->dnsq_prev->dnsq_next : ctx->dnsc_qactive.head)); ++nactive; } assert(nactive == ctx->dnsc_nactive); } #endif enum { DNS_INTERNAL = 0xffff, /* internal flags mask */ DNS_INITED = 0x0001, /* the context is initialized */ DNS_ASIS_DONE = 0x0002, /* search: skip the last as-is query */ DNS_SEEN_NODATA = 0x0004, /* search: NODATA has been received */ }; int dns_add_serv(struct dns_ctx *ctx, const char *serv) { union sockaddr_ns *sns; SETCTXFRESH(ctx); if (!serv) return (ctx->dnsc_nserv = 0); if (ctx->dnsc_nserv >= DNS_MAXSERV) return errno = ENFILE, -1; sns = &ctx->dnsc_serv[ctx->dnsc_nserv]; memset(sns, 0, sizeof(*sns)); if (dns_pton(AF_INET, serv, &sns->sin.sin_addr) > 0) { sns->sin.sin_family = AF_INET; return ++ctx->dnsc_nserv; } #ifdef HAVE_IPv6 if (dns_pton(AF_INET6, serv, &sns->sin6.sin6_addr) > 0) { sns->sin6.sin6_family = AF_INET6; return ++ctx->dnsc_nserv; } #endif errno = EINVAL; return -1; } int dns_add_serv_s(struct dns_ctx *ctx, const struct sockaddr *sa) { SETCTXFRESH(ctx); if (!sa) return (ctx->dnsc_nserv = 0); if (ctx->dnsc_nserv >= DNS_MAXSERV) return errno = ENFILE, -1; #ifdef HAVE_IPv6 else if (sa->sa_family == AF_INET6) ctx->dnsc_serv[ctx->dnsc_nserv].sin6 = *(struct sockaddr_in6*)sa; #endif else if (sa->sa_family == AF_INET) ctx->dnsc_serv[ctx->dnsc_nserv].sin = *(struct sockaddr_in*)sa; else return errno = EAFNOSUPPORT, -1; return ++ctx->dnsc_nserv; } int dns_set_opts(struct dns_ctx *ctx, const char *opts) { unsigned i, v; int err = 0; SETCTXINACTIVE(ctx); for(;;) { while(ISSPACE(*opts)) ++opts; if (!*opts) break; for(i = 0; ; ++i) { if (i >= sizeof(dns_opts)/sizeof(dns_opts[0])) { ++err; break; } v = strlen(dns_opts[i].name); if (strncmp(dns_opts[i].name, opts, v) != 0 || (opts[v] != ':' && opts[v] != '=')) continue; opts += v + 1; v = 0; if (*opts < '0' || *opts > '9') { ++err; break; } do v = v * 10 + (*opts++ - '0'); while (*opts >= '0' && *opts <= '9'); if (v < dns_opts[i].min) v = dns_opts[i].min; if (v > dns_opts[i].max) v = dns_opts[i].max; dns_ctxopt(ctx, i) = v; break; } while(*opts && !ISSPACE(*opts)) ++opts; } return err; } int dns_set_opt(struct dns_ctx *ctx, enum dns_opt opt, int val) { int prev; unsigned i; SETCTXINACTIVE(ctx); for(i = 0; i < sizeof(dns_opts)/sizeof(dns_opts[0]); ++i) { if (dns_opts[i].opt != opt) continue; prev = dns_ctxopt(ctx, i); if (val >= 0) { unsigned v = val; if (v < dns_opts[i].min || v > dns_opts[i].max) { errno = EINVAL; return -1; } dns_ctxopt(ctx, i) = v; } return prev; } if (opt == DNS_OPT_FLAGS) { prev = ctx->dnsc_flags & ~DNS_INTERNAL; if (val >= 0) ctx->dnsc_flags = (ctx->dnsc_flags & DNS_INTERNAL) | (val & ~DNS_INTERNAL); return prev; } errno = ENOSYS; return -1; } int dns_add_srch(struct dns_ctx *ctx, const char *srch) { int dnl; SETCTXINACTIVE(ctx); if (!srch) { memset(ctx->dnsc_srchbuf, 0, sizeof(ctx->dnsc_srchbuf)); ctx->dnsc_srchend = ctx->dnsc_srchbuf; return 0; } dnl = sizeof(ctx->dnsc_srchbuf) - (ctx->dnsc_srchend - ctx->dnsc_srchbuf) - 1; dnl = dns_sptodn(srch, ctx->dnsc_srchend, dnl); if (dnl > 0) ctx->dnsc_srchend += dnl; ctx->dnsc_srchend[0] = '\0'; /* we ensure the list is always ends at . */ if (dnl > 0) return 0; errno = EINVAL; return -1; } static void dns_drop_utm(struct dns_ctx *ctx) { if (ctx->dnsc_utmfn) ctx->dnsc_utmfn(NULL, -1, ctx->dnsc_utmctx); ctx->dnsc_utmctx = NULL; ctx->dnsc_utmexp = -1; } static void _dns_request_utm(struct dns_ctx *ctx, time_t now) { struct dns_query *q; time_t deadline; int timeout; q = ctx->dnsc_qactive.head; if (!q) deadline = -1, timeout = -1; else if (!now || q->dnsq_deadline <= now) deadline = 0, timeout = 0; else deadline = q->dnsq_deadline, timeout = (int)(deadline - now); if (ctx->dnsc_utmexp == deadline) return; ctx->dnsc_utmfn(ctx, timeout, ctx->dnsc_utmctx); ctx->dnsc_utmexp = deadline; } static __inline void dns_request_utm(struct dns_ctx *ctx, time_t now) { if (ctx->dnsc_utmfn) _dns_request_utm(ctx, now); } void dns_set_dbgfn(struct dns_ctx *ctx, dns_dbgfn *dbgfn) { SETCTXINITED(ctx); ctx->dnsc_udbgfn = dbgfn; } void dns_set_tmcbck(struct dns_ctx *ctx, dns_utm_fn *fn, void *data) { SETCTXINITED(ctx); dns_drop_utm(ctx); ctx->dnsc_utmfn = fn; ctx->dnsc_utmctx = data; if (CTXOPEN(ctx)) dns_request_utm(ctx, 0); } static unsigned dns_nonrandom_32(void) { #ifdef WINDOWS FILETIME ft; GetSystemTimeAsFileTime(&ft); return ft.dwLowDateTime; #else struct timeval tv; gettimeofday(&tv, NULL); return tv.tv_usec; #endif } /* This is historic deprecated API */ UDNS_API unsigned dns_random16(void); unsigned dns_random16(void) { unsigned x = dns_nonrandom_32(); return (x ^ (x >> 16)) & 0xffff; } static void dns_init_rng(struct dns_ctx *ctx) { udns_jraninit(&ctx->dnsc_jran, dns_nonrandom_32()); ctx->dnsc_nextid = 0; } void dns_close(struct dns_ctx *ctx) { struct dns_query *q, *p; SETCTX(ctx); if (CTXINITED(ctx)) { if (ctx->dnsc_udpsock >= 0) closesocket(ctx->dnsc_udpsock); ctx->dnsc_udpsock = -1; if (ctx->dnsc_pbuf) free(ctx->dnsc_pbuf); ctx->dnsc_pbuf = NULL; q = ctx->dnsc_qactive.head; while((p = q) != NULL) { q = q->dnsq_next; free(p); } qlist_init(&ctx->dnsc_qactive); ctx->dnsc_nactive = 0; dns_drop_utm(ctx); } } void dns_reset(struct dns_ctx *ctx) { SETCTX(ctx); dns_close(ctx); memset(ctx, 0, sizeof(*ctx)); ctx->dnsc_timeout = 4; ctx->dnsc_ntries = 3; ctx->dnsc_ndots = 1; ctx->dnsc_udpbuf = DNS_EDNS0PACKET; ctx->dnsc_port = DNS_PORT; ctx->dnsc_udpsock = -1; ctx->dnsc_srchend = ctx->dnsc_srchbuf; qlist_init(&ctx->dnsc_qactive); dns_init_rng(ctx); ctx->dnsc_flags = DNS_INITED; } struct dns_ctx *dns_new(const struct dns_ctx *copy) { struct dns_ctx *ctx; SETCTXINITED(copy); dns_assert_ctx(copy); ctx = malloc(sizeof(*ctx)); if (!ctx) return NULL; *ctx = *copy; ctx->dnsc_udpsock = -1; qlist_init(&ctx->dnsc_qactive); ctx->dnsc_nactive = 0; ctx->dnsc_pbuf = NULL; ctx->dnsc_qstatus = 0; ctx->dnsc_srchend = ctx->dnsc_srchbuf + (copy->dnsc_srchend - copy->dnsc_srchbuf); ctx->dnsc_utmfn = NULL; ctx->dnsc_utmctx = NULL; dns_init_rng(ctx); return ctx; } void dns_free(struct dns_ctx *ctx) { assert(ctx != NULL && ctx != &dns_defctx); dns_reset(ctx); free(ctx); } int dns_open(struct dns_ctx *ctx) { int sock; unsigned i; int port; union sockaddr_ns *sns; #ifdef HAVE_IPv6 unsigned have_inet6 = 0; #endif SETCTXINITED(ctx); assert(!CTXOPEN(ctx)); port = htons((unsigned short)ctx->dnsc_port); /* ensure we have at least one server */ if (!ctx->dnsc_nserv) { sns = ctx->dnsc_serv; sns->sin.sin_family = AF_INET; sns->sin.sin_addr.s_addr = htonl(INADDR_LOOPBACK); ctx->dnsc_nserv = 1; } for (i = 0; i < ctx->dnsc_nserv; ++i) { sns = &ctx->dnsc_serv[i]; /* set port for each sockaddr */ #ifdef HAVE_IPv6 if (sns->sa.sa_family == AF_INET6) { if (!sns->sin6.sin6_port) sns->sin6.sin6_port = (unsigned short)port; ++have_inet6; } else #endif { assert(sns->sa.sa_family == AF_INET); if (!sns->sin.sin_port) sns->sin.sin_port = (unsigned short)port; } } #ifdef HAVE_IPv6 if (have_inet6 && have_inet6 < ctx->dnsc_nserv) { /* convert all IPv4 addresses to IPv6 V4MAPPED */ struct sockaddr_in6 sin6; memset(&sin6, 0, sizeof(sin6)); sin6.sin6_family = AF_INET6; /* V4MAPPED: ::ffff:1.2.3.4 */ sin6.sin6_addr.s6_addr[10] = 0xff; sin6.sin6_addr.s6_addr[11] = 0xff; for(i = 0; i < ctx->dnsc_nserv; ++i) { sns = &ctx->dnsc_serv[i]; if (sns->sa.sa_family == AF_INET) { sin6.sin6_port = sns->sin.sin_port; memcpy(sin6.sin6_addr.s6_addr + 4*3, &sns->sin.sin_addr, 4); sns->sin6 = sin6; } } } ctx->dnsc_salen = have_inet6 ? sizeof(struct sockaddr_in6) : sizeof(struct sockaddr_in); if (have_inet6) sock = socket(PF_INET6, SOCK_DGRAM, IPPROTO_UDP); else sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP); #else /* !HAVE_IPv6 */ sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP); ctx->dnsc_salen = sizeof(struct sockaddr_in); #endif /* HAVE_IPv6 */ if (sock < 0) { ctx->dnsc_qstatus = DNS_E_TEMPFAIL; return -1; } #ifdef WINDOWS { unsigned long on = 1; if (ioctlsocket(sock, FIONBIO, &on) == SOCKET_ERROR) { closesocket(sock); ctx->dnsc_qstatus = DNS_E_TEMPFAIL; return -1; } } #else /* !WINDOWS */ if (fcntl(sock, F_SETFL, fcntl(sock, F_GETFL) | O_NONBLOCK) < 0 || fcntl(sock, F_SETFD, FD_CLOEXEC) < 0) { closesocket(sock); ctx->dnsc_qstatus = DNS_E_TEMPFAIL; return -1; } #endif /* WINDOWS */ /* allocate the packet buffer */ if ((ctx->dnsc_pbuf = malloc(ctx->dnsc_udpbuf)) == NULL) { closesocket(sock); ctx->dnsc_qstatus = DNS_E_NOMEM; errno = ENOMEM; return -1; } ctx->dnsc_udpsock = sock; dns_request_utm(ctx, 0); return sock; } int dns_sock(const struct dns_ctx *ctx) { SETCTXINITED(ctx); return ctx->dnsc_udpsock; } int dns_active(const struct dns_ctx *ctx) { SETCTXINITED(ctx); dns_assert_ctx(ctx); return ctx->dnsc_nactive; } int dns_status(const struct dns_ctx *ctx) { SETCTX(ctx); return ctx->dnsc_qstatus; } void dns_setstatus(struct dns_ctx *ctx, int status) { SETCTX(ctx); ctx->dnsc_qstatus = status; } /* End the query: disconnect it from the active list, free it, * and return the result to the caller. */ static void dns_end_query(struct dns_ctx *ctx, struct dns_query *q, int status, void *result) { dns_query_fn *cbck = q->dnsq_cbck; void *cbdata = q->dnsq_cbdata; ctx->dnsc_qstatus = status; assert((status < 0 && result == 0) || (status >= 0 && result != 0)); assert(cbck != 0); /*XXX callback may be NULL */ assert(ctx->dnsc_nactive > 0); --ctx->dnsc_nactive; qlist_remove(&ctx->dnsc_qactive, q); /* force the query to be unconnected */ /*memset(q, 0, sizeof(*q));*/ #ifndef NDEBUG q->dnsq_ctx = NULL; #endif free(q); cbck(ctx, result, cbdata); } #define DNS_DBG(ctx, code, sa, slen, pkt, plen) \ do { \ if (ctx->dnsc_udbgfn) \ ctx->dnsc_udbgfn(code, (sa), slen, pkt, plen, 0, 0); \ } while(0) #define DNS_DBGQ(ctx, q, code, sa, slen, pkt, plen) \ do { \ if (ctx->dnsc_udbgfn) \ ctx->dnsc_udbgfn(code, (sa), slen, pkt, plen, q, q->dnsq_cbdata); \ } while(0) static void dns_newid(struct dns_ctx *ctx, struct dns_query *q) { /* this is how we choose an identifier for a new query (qID). * For now, it's just sequential number, incremented for every query, and * thus obviously trivial to guess. * There are two choices: * a) use sequential numbers. It is plain insecure. In DNS, there are two * places where random numbers are (or can) be used to increase security: * random qID and random source port number. Without this randomness * (udns uses fixed port for all queries), or when the randomness is weak, * it's trivial to spoof query replies. With randomness however, it * becomes a bit more difficult task. Too bad we only have 16 bits for * our security, as qID is only two bytes. It isn't a security per se, * to rely on those 16 bits - an attacker can just flood us with fake * replies with all possible qIDs (only 65536 of them), and in this case, * even if we'll use true random qIDs, we'll be in trouble (not protected * against spoofing). Yes, this is only possible on a high-speed network * (probably on the LAN only, since usually a border router for a LAN * protects internal machines from packets with spoofed local addresses * from outside, and usually a nameserver resides on LAN), but it's * still very well possible to send us fake replies. * In other words: there's nothing a DNS (stub) resolver can do against * spoofing attacks, unless DNSSEC is in use, which helps here alot. * Too bad that DNSSEC isn't widespread, so relying on it isn't an * option in almost all cases... * b) use random qID, based on some random-number generation mechanism. * This way, we increase our protection a bit (see above - it's very weak * still), but we also increase risk of qID reuse and matching late replies * that comes to queries we've sent before against new queries. There are * some more corner cases around that, as well - for example, normally, * udns tries to find the query for a given reply by qID, *and* by * verifying that the query DN and other parameters are also the same * (so if the new query is against another domain name, old reply will * be ignored automatically). But certain types of replies which we now * handle - for example, FORMERR reply from servers which refuses to * process EDNS0-enabled packets - comes without all the query parameters * but the qID - so we're forced to use qID only when determining which * query the given reply corresponds to. This makes us even more * vulnerable to spoofing attacks, because an attacker don't even need to * know which queries we perform to spoof the replies - he only needs to * flood us with fake FORMERR "replies". * * That all to say: using sequential (or any other trivially guessable) * numbers for qIDs is insecure, but the whole thing is inherently insecure * as well, and this "extra weakness" that comes from weak qID choosing * algorithm adds almost nothing to the underlying problem. * * It CAN NOT be made secure. Period. That's it. * Unless we choose to implement DNSSEC, which is a whole different story. * Forcing TCP mode makes it better, but who uses TCP for DNS anyway? * (and it's hardly possible because of huge impact on the recursive * nameservers). * * Note that ALL stub resolvers (again, unless they implement and enforce * DNSSEC) suffers from this same problem. * * Here, I use a pseudo-random number generator for qIDs, instead of a * simpler sequential IDs. This is _not_ more secure than sequential * ID, but some found random IDs more enjoyeable for some reason. So * here it goes. */ /* Use random number and check if it's unique. * If it's not, try again up to 5 times. */ unsigned loop; dnsc_t c0, c1; for(loop = 0; loop < 5; ++loop) { const struct dns_query *c; if (!ctx->dnsc_nextid) ctx->dnsc_nextid = udns_jranval(&ctx->dnsc_jran); c0 = ctx->dnsc_nextid & 0xff; c1 = (ctx->dnsc_nextid >> 8) & 0xff; ctx->dnsc_nextid >>= 16; for(c = ctx->dnsc_qactive.head; c; c = c->dnsq_next) if (c->dnsq_id[0] == c0 && c->dnsq_id[1] == c1) break; /* found such entry, try again */ if (!c) break; } q->dnsq_id[0] = c0; q->dnsq_id[1] = c1; /* reset all parameters relevant for previous query lifetime */ q->dnsq_try = 0; q->dnsq_servi = 0; /*XXX probably should keep dnsq_servnEDNS0 bits? * See also comments in dns_ioevent() about FORMERR case */ q->dnsq_servwait = q->dnsq_servskip = q->dnsq_servnEDNS0 = 0; } /* Find next search suffix and fills in q->dnsq_dn. * Return 0 if no more to try. */ static int dns_next_srch(struct dns_ctx *ctx, struct dns_query *q) { unsigned dnl; for(;;) { if (q->dnsq_nxtsrch > ctx->dnsc_srchend) return 0; dnl = dns_dnlen(q->dnsq_nxtsrch); if (dnl + q->dnsq_origdnl0 <= DNS_MAXDN && (*q->dnsq_nxtsrch || !(q->dnsq_flags & DNS_ASIS_DONE))) break; q->dnsq_nxtsrch += dnl; } memcpy(q->dnsq_dn + q->dnsq_origdnl0, q->dnsq_nxtsrch, dnl); if (!*q->dnsq_nxtsrch) q->dnsq_flags |= DNS_ASIS_DONE; q->dnsq_nxtsrch += dnl; dns_newid(ctx, q); /* new ID for new qDN */ return 1; } /* find the server to try for current iteration. * Note that current dnsq_servi may point to a server we should skip -- * in that case advance to the next server. * Return true if found, false if all tried. */ static int dns_find_serv(const struct dns_ctx *ctx, struct dns_query *q) { while(q->dnsq_servi < ctx->dnsc_nserv) { if (!(q->dnsq_servskip & (1 << q->dnsq_servi))) return 1; ++q->dnsq_servi; } return 0; } /* format and send the query to a given server. * In case of network problem (sendto() fails), return -1, * else return 0. */ static int dns_send_this(struct dns_ctx *ctx, struct dns_query *q, unsigned servi, time_t now) { unsigned qlen; unsigned tries; { /* format the query buffer */ dnsc_t *p = ctx->dnsc_pbuf; memset(p, 0, DNS_HSIZE); if (!(q->dnsq_flags & DNS_NORD)) p[DNS_H_F1] |= DNS_HF1_RD; if (q->dnsq_flags & DNS_AAONLY) p[DNS_H_F1] |= DNS_HF1_AA; if (q->dnsq_flags & DNS_SET_CD) p[DNS_H_F2] |= DNS_HF2_CD; p[DNS_H_QDCNT2] = 1; memcpy(p + DNS_H_QID, q->dnsq_id, 2); p = dns_payload(p); /* copy query dn */ p += dns_dntodn(q->dnsq_dn, p, DNS_MAXDN); /* query type and class */ memcpy(p, q->dnsq_typcls, 4); p += 4; /* add EDNS0 record. DO flag requires it */ if (q->dnsq_flags & DNS_SET_DO || (ctx->dnsc_udpbuf > DNS_MAXPACKET && !(q->dnsq_servnEDNS0 & (1 << servi)))) { *p++ = 0; /* empty (root) DN */ p = dns_put16(p, DNS_T_OPT); p = dns_put16(p, ctx->dnsc_udpbuf); /* EDNS0 RCODE & VERSION; rest of the TTL field; RDLEN */ memset(p, 0, 2+2+2); if (q->dnsq_flags & DNS_SET_DO) p[2] |= DNS_EF1_DO; p += 2+2+2; ctx->dnsc_pbuf[DNS_H_ARCNT2] = 1; } qlen = p - ctx->dnsc_pbuf; assert(qlen <= ctx->dnsc_udpbuf); } /* send the query */ tries = 10; while (sendto(ctx->dnsc_udpsock, (void*)ctx->dnsc_pbuf, qlen, 0, &ctx->dnsc_serv[servi].sa, ctx->dnsc_salen) < 0) { /*XXX just ignore the sendto() error for now and try again. * In the future, it may be possible to retrieve the error code * and find which operation/query failed. *XXX try the next server too? (if ENETUNREACH is returned immediately) */ if (--tries) continue; /* if we can't send the query, fail it. */ dns_end_query(ctx, q, DNS_E_TEMPFAIL, 0); return -1; } DNS_DBGQ(ctx, q, 1, &ctx->dnsc_serv[servi].sa, sizeof(union sockaddr_ns), ctx->dnsc_pbuf, qlen); q->dnsq_servwait |= 1 << servi; /* expect reply from this ns */ q->dnsq_deadline = now + (dns_find_serv(ctx, q) ? 1 : ctx->dnsc_timeout << q->dnsq_try); /* move the query to the proper place, according to the new deadline */ qlist_remove(&ctx->dnsc_qactive, q); { /* insert from the tail */ struct dns_query *p; for(p = ctx->dnsc_qactive.tail; p; p = p->dnsq_prev) if (p->dnsq_deadline <= q->dnsq_deadline) break; qlist_insert_after(&ctx->dnsc_qactive, q, p); } return 0; } /* send the query out using next available server * and add it to the active list, or, if no servers available, * end it. */ static void dns_send(struct dns_ctx *ctx, struct dns_query *q, time_t now) { /* if we can't send the query, return TEMPFAIL even when searching: * we can't be sure whenever the name we tried to search exists or not, * so don't continue searching, or we may find the wrong name. */ if (!dns_find_serv(ctx, q)) { /* no more servers in this iteration. Try the next cycle */ q->dnsq_servi = 0; /* reset */ q->dnsq_try++; /* next try */ if (q->dnsq_try >= ctx->dnsc_ntries || !dns_find_serv(ctx, q)) { /* no more servers and tries, fail the query */ /* return TEMPFAIL even when searching: no more tries for this * searchlist, and no single definitive reply (handled in dns_ioevent() * in NOERROR or NXDOMAIN cases) => all nameservers failed to process * current search list element, so we don't know whenever the name exists. */ dns_end_query(ctx, q, DNS_E_TEMPFAIL, 0); return; } } dns_send_this(ctx, q, q->dnsq_servi++, now); } static void dns_dummy_cb(struct dns_ctx *unused_ctx, void *result, void *unused_data) { if (result) free(result); (void)unused_ctx; (void)unused_data; /* avoid warning */ } /* The (only, main, real) query submission routine. * Allocate new query structure, initialize it, check validity of * parameters, and add it to the head of the active list, without * trying to send it (to be picked up on next event). * Error return (without calling the callback routine) - * no memory or wrong parameters. *XXX The `no memory' case probably should go to the callback anyway... */ struct dns_query * dns_submit_dn(struct dns_ctx *ctx, dnscc_t *dn, int qcls, int qtyp, int flags, dns_parse_fn *parse, dns_query_fn *cbck, void *data) { struct dns_query *q; SETCTXOPEN(ctx); dns_assert_ctx(ctx); q = calloc(sizeof(*q), 1); if (!q) { ctx->dnsc_qstatus = DNS_E_NOMEM; return NULL; } #ifndef NDEBUG q->dnsq_ctx = ctx; #endif q->dnsq_parse = parse; q->dnsq_cbck = cbck ? cbck : dns_dummy_cb; q->dnsq_cbdata = data; q->dnsq_origdnl0 = dns_dntodn(dn, q->dnsq_dn, sizeof(q->dnsq_dn)); assert(q->dnsq_origdnl0 > 0); --q->dnsq_origdnl0; /* w/o the trailing 0 */ dns_put16(q->dnsq_typcls+0, qtyp); dns_put16(q->dnsq_typcls+2, qcls); q->dnsq_flags = (flags | ctx->dnsc_flags) & ~DNS_INTERNAL; if (flags & DNS_NOSRCH || dns_dnlabels(q->dnsq_dn) > ctx->dnsc_ndots) { q->dnsq_nxtsrch = flags & DNS_NOSRCH ? ctx->dnsc_srchend /* end of the search list if no search requested */ : ctx->dnsc_srchbuf /* beginning of the list, but try as-is first */; q->dnsq_flags |= DNS_ASIS_DONE; dns_newid(ctx, q); } else { q->dnsq_nxtsrch = ctx->dnsc_srchbuf; dns_next_srch(ctx, q); } /* q->dnsq_deadline is set to 0 (calloc above): the new query is * "already expired" when first inserted into queue, so it's safe * to insert it into the head of the list. Next call to dns_timeouts() * will actually send it. */ qlist_add_head(&ctx->dnsc_qactive, q); ++ctx->dnsc_nactive; dns_request_utm(ctx, 0); return q; } struct dns_query * dns_submit_p(struct dns_ctx *ctx, const char *name, int qcls, int qtyp, int flags, dns_parse_fn *parse, dns_query_fn *cbck, void *data) { int isabs; SETCTXOPEN(ctx); if (dns_ptodn(name, 0, ctx->dnsc_pbuf, DNS_MAXDN, &isabs) <= 0) { ctx->dnsc_qstatus = DNS_E_BADQUERY; return NULL; } if (isabs) flags |= DNS_NOSRCH; return dns_submit_dn(ctx, ctx->dnsc_pbuf, qcls, qtyp, flags, parse, cbck, data); } /* process readable fd condition. * To be usable in edge-triggered environment, the routine * should consume all input so it should loop over. * Note it isn't really necessary to loop here, because * an application may perform the loop just fine by it's own, * but in this case we should return some sensitive result, * to indicate when to stop calling and error conditions. * Note also we may encounter all sorts of recvfrom() * errors which aren't fatal, and at the same time we may * loop forever if an error IS fatal. */ void dns_ioevent(struct dns_ctx *ctx, time_t now) { int r; unsigned servi; struct dns_query *q; dnsc_t *pbuf; dnscc_t *pend, *pcur; void *result; union sockaddr_ns sns; socklen_t slen; SETCTX(ctx); if (!CTXOPEN(ctx)) return; dns_assert_ctx(ctx); pbuf = ctx->dnsc_pbuf; if (!now) now = time(NULL); again: /* receive the reply */ slen = sizeof(sns); r = recvfrom(ctx->dnsc_udpsock, (void*)pbuf, ctx->dnsc_udpbuf, MSG_DONTWAIT, &sns.sa, &slen); if (r < 0) { /*XXX just ignore recvfrom() errors for now. * in the future it may be possible to determine which * query failed and requeue it. * Note there may be various error conditions, triggered * by both local problems and remote problems. It isn't * quite trivial to determine whenever an error is local * or remote. On local errors, we should stop, while * remote errors should be ignored (for now anyway). */ #ifdef WINDOWS if (WSAGetLastError() == WSAEWOULDBLOCK) #else if (errno == EAGAIN) #endif { dns_request_utm(ctx, now); return; } goto again; } pend = pbuf + r; pcur = dns_payload(pbuf); /* check reply header */ if (pcur > pend || dns_numqd(pbuf) > 1 || dns_opcode(pbuf) != 0) { DNS_DBG(ctx, -1/*bad reply*/, &sns.sa, slen, pbuf, r); goto again; } /* find the matching query, by qID */ for (q = ctx->dnsc_qactive.head; ; q = q->dnsq_next) { if (!q) { /* no more requests: old reply? */ DNS_DBG(ctx, -5/*no matching query*/, &sns.sa, slen, pbuf, r); goto again; } if (pbuf[DNS_H_QID1] == q->dnsq_id[0] && pbuf[DNS_H_QID2] == q->dnsq_id[1]) break; } /* if we have numqd, compare with our query qDN */ if (dns_numqd(pbuf)) { /* decode the qDN */ dnsc_t dn[DNS_MAXDN]; if (dns_getdn(pbuf, &pcur, pend, dn, sizeof(dn)) < 0 || pcur + 4 > pend) { DNS_DBG(ctx, -1/*bad reply*/, &sns.sa, slen, pbuf, r); goto again; } if (!dns_dnequal(dn, q->dnsq_dn) || memcmp(pcur, q->dnsq_typcls, 4) != 0) { /* not this query */ DNS_DBG(ctx, -5/*no matching query*/, &sns.sa, slen, pbuf, r); goto again; } /* here, query match, and pcur points past qDN in query section in pbuf */ } /* if no numqd, we only allow FORMERR rcode */ else if (dns_rcode(pbuf) != DNS_R_FORMERR) { /* treat it as bad reply if !FORMERR */ DNS_DBG(ctx, -1/*bad reply*/, &sns.sa, slen, pbuf, r); goto again; } else { /* else it's FORMERR, handled below */ } /* find server */ #ifdef HAVE_IPv6 if (sns.sa.sa_family == AF_INET6 && slen >= sizeof(sns.sin6)) { for(servi = 0; servi < ctx->dnsc_nserv; ++servi) if (sin6_eq(ctx->dnsc_serv[servi].sin6, sns.sin6)) break; } else #endif if (sns.sa.sa_family == AF_INET && slen >= sizeof(sns.sin)) { for(servi = 0; servi < ctx->dnsc_nserv; ++servi) if (sin_eq(ctx->dnsc_serv[servi].sin, sns.sin)) break; } else servi = ctx->dnsc_nserv; /* check if we expect reply from this server. * Note we can receive reply from first try if we're already at next */ if (!(q->dnsq_servwait & (1 << servi))) { /* if ever asked this NS */ DNS_DBG(ctx, -2/*wrong server*/, &sns.sa, slen, pbuf, r); goto again; } /* we got (some) reply for our query */ DNS_DBGQ(ctx, q, 0, &sns.sa, slen, pbuf, r); q->dnsq_servwait &= ~(1 << servi); /* don't expect reply from this serv */ /* process the RCODE */ switch(dns_rcode(pbuf)) { case DNS_R_NOERROR: if (dns_tc(pbuf)) { /* possible truncation. We can't deal with it. */ /*XXX for now, treat TC bit the same as SERVFAIL. * It is possible to: * a) try to decode the reply - may be ANSWER section is ok; * b) check if server understands EDNS0, and if it is, and * answer still don't fit, end query. */ break; } if (!dns_numan(pbuf)) { /* no data of requested type */ if (dns_next_srch(ctx, q)) { /* if we're searching, try next searchlist element, * but remember NODATA reply. */ q->dnsq_flags |= DNS_SEEN_NODATA; dns_send(ctx, q, now); } else /* else - nothing to search any more - finish the query. * It will be NODATA since we've seen a NODATA reply. */ dns_end_query(ctx, q, DNS_E_NODATA, 0); } /* we've got a positive reply here */ else if (q->dnsq_parse) { /* if we have parsing routine, call it and return whatever it returned */ /* don't try to re-search if NODATA here. For example, * if we asked for A but only received CNAME. Unless we'll * someday do recursive queries. And that's problematic too, since * we may be dealing with specific AA-only nameservers for a given * domain, but CNAME points elsewhere... */ r = q->dnsq_parse(q->dnsq_dn, pbuf, pcur, pend, &result); dns_end_query(ctx, q, r, r < 0 ? NULL : result); } /* else just malloc+copy the raw DNS reply */ else if ((result = malloc(r)) == NULL) dns_end_query(ctx, q, DNS_E_NOMEM, NULL); else { memcpy(result, pbuf, r); dns_end_query(ctx, q, r, result); } goto again; case DNS_R_NXDOMAIN: /* Non-existing domain. */ if (dns_next_srch(ctx, q)) /* more search entries exists, try them. */ dns_send(ctx, q, now); else /* nothing to search anymore. End the query, returning either NODATA * if we've seen it before, or NXDOMAIN if not. */ dns_end_query(ctx, q, q->dnsq_flags & DNS_SEEN_NODATA ? DNS_E_NODATA : DNS_E_NXDOMAIN, 0); goto again; case DNS_R_FORMERR: case DNS_R_NOTIMPL: /* for FORMERR and NOTIMPL rcodes, if we tried EDNS0-enabled query, * try w/o EDNS0. */ if (ctx->dnsc_udpbuf > DNS_MAXPACKET && !(q->dnsq_servnEDNS0 & (1 << servi))) { /* we always trying EDNS0 first if enabled, and retry a given query * if not available. Maybe it's better to remember inavailability of * EDNS0 in ctx as a per-NS flag, and never try again for this NS. * For long-running applications.. maybe they will change the nameserver * while we're running? :) Also, since FORMERR is the only rcode we * allow to be header-only, and in this case the only check we do to * find a query it belongs to is qID (not qDN+qCLS+qTYP), it's much * easier to spoof and to force us to perform non-EDNS0 queries only... */ q->dnsq_servnEDNS0 |= 1 << servi; dns_send_this(ctx, q, servi, now); goto again; } /* else we handle it the same as SERVFAIL etc */ case DNS_R_SERVFAIL: case DNS_R_REFUSED: /* for these rcodes, advance this request * to the next server and reschedule */ default: /* unknown rcode? hmmm... */ break; } /* here, we received unexpected reply */ q->dnsq_servskip |= (1 << servi); /* don't retry this server */ /* we don't expect replies from this server anymore. * But there may be other servers. Some may be still processing our * query, and some may be left to try. * We just ignore this reply and wait a bit more if some NSes haven't * replied yet (dnsq_servwait != 0), and let the situation to be handled * on next event processing. Timeout for this query is set correctly, * if not taking into account the one-second difference - we can try * next server in the same iteration sooner. */ /* try next server */ if (!q->dnsq_servwait) { /* next retry: maybe some other servers will reply next time. * dns_send() will end the query for us if no more servers to try. * Note we can't continue with the next searchlist element here: * we don't know if the current qdn exists or not, there's no definitive * answer yet (which is seen in cases above). *XXX standard resolver also tries as-is query in case all nameservers * failed to process our query and if not tried before. We don't do it. */ dns_send(ctx, q, now); } else { /* else don't do anything - not all servers replied yet */ } goto again; } /* handle all timeouts */ int dns_timeouts(struct dns_ctx *ctx, int maxwait, time_t now) { /* this is a hot routine */ struct dns_query *q; SETCTX(ctx); dns_assert_ctx(ctx); /* Pick up first entry from query list. * If its deadline has passed, (re)send it * (dns_send() will move it next in the list). * If not, this is the query which determines the closest deadline. */ q = ctx->dnsc_qactive.head; if (!q) return maxwait; if (!now) now = time(NULL); do { if (q->dnsq_deadline > now) { /* first non-expired query */ int w = (int)(q->dnsq_deadline - now); if (maxwait < 0 || maxwait > w) maxwait = w; break; } else { /* process expired deadline */ dns_send(ctx, q, now); } } while((q = ctx->dnsc_qactive.head) != NULL); dns_request_utm(ctx, now); /* update timer with new deadline */ return maxwait; } struct dns_resolve_data { int dnsrd_done; void *dnsrd_result; }; static void dns_resolve_cb(struct dns_ctx *ctx, void *result, void *data) { struct dns_resolve_data *d = data; d->dnsrd_result = result; d->dnsrd_done = 1; ctx = ctx; } void *dns_resolve(struct dns_ctx *ctx, struct dns_query *q) { time_t now; struct dns_resolve_data d; int n; SETCTXOPEN(ctx); if (!q) return NULL; assert(ctx == q->dnsq_ctx); dns_assert_ctx(ctx); /* do not allow re-resolving synchronous queries */ assert(q->dnsq_cbck != dns_resolve_cb && "can't resolve synchronous query"); if (q->dnsq_cbck == dns_resolve_cb) { ctx->dnsc_qstatus = DNS_E_BADQUERY; return NULL; } q->dnsq_cbck = dns_resolve_cb; q->dnsq_cbdata = &d; d.dnsrd_done = 0; now = time(NULL); while(!d.dnsrd_done && (n = dns_timeouts(ctx, -1, now)) >= 0) { #ifdef HAVE_POLL struct pollfd pfd; pfd.fd = ctx->dnsc_udpsock; pfd.events = POLLIN; n = poll(&pfd, 1, n * 1000); #else fd_set rfd; struct timeval tv; FD_ZERO(&rfd); FD_SET(ctx->dnsc_udpsock, &rfd); tv.tv_sec = n; tv.tv_usec = 0; n = select(ctx->dnsc_udpsock + 1, &rfd, NULL, NULL, &tv); #endif now = time(NULL); if (n > 0) dns_ioevent(ctx, now); } return d.dnsrd_result; } void *dns_resolve_dn(struct dns_ctx *ctx, dnscc_t *dn, int qcls, int qtyp, int flags, dns_parse_fn *parse) { return dns_resolve(ctx, dns_submit_dn(ctx, dn, qcls, qtyp, flags, parse, NULL, NULL)); } void *dns_resolve_p(struct dns_ctx *ctx, const char *name, int qcls, int qtyp, int flags, dns_parse_fn *parse) { return dns_resolve(ctx, dns_submit_p(ctx, name, qcls, qtyp, flags, parse, NULL, NULL)); } int dns_cancel(struct dns_ctx *ctx, struct dns_query *q) { SETCTX(ctx); dns_assert_ctx(ctx); assert(q->dnsq_ctx == ctx); /* do not allow cancelling synchronous queries */ assert(q->dnsq_cbck != dns_resolve_cb && "can't cancel synchronous query"); if (q->dnsq_cbck == dns_resolve_cb) return (ctx->dnsc_qstatus = DNS_E_BADQUERY); qlist_remove(&ctx->dnsc_qactive, q); --ctx->dnsc_nactive; dns_request_utm(ctx, 0); return 0; } udns-0.6/udns_init.c0000644000175000017500000001527314571041062012646 0ustar mjtmjt/* udns_init.c resolver initialisation stuff Copyright (C) 2006 Michael Tokarev This file is part of UDNS library, an async DNS stub resolver. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library, in file named COPYING.LGPL; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #ifdef HAVE_CONFIG_H # include "config.h" #endif #ifdef WINDOWS # include /* includes */ # include /* for dns server addresses etc */ #else # include # include # include #endif /* !WINDOWS */ #include #include #include "udns.h" #define ISSPACE(x) (x == ' ' || x == '\t' || x == '\r' || x == '\n') static const char space[] = " \t\r\n"; static void dns_set_serv_internal(struct dns_ctx *ctx, char *serv) { dns_add_serv(ctx, NULL); for(serv = strtok(serv, space); serv; serv = strtok(NULL, space)) dns_add_serv(ctx, serv); } static void dns_set_srch_internal(struct dns_ctx *ctx, char *srch) { dns_add_srch(ctx, NULL); for(srch = strtok(srch, space); srch; srch = strtok(NULL, space)) dns_add_srch(ctx, srch); } #ifdef WINDOWS #ifndef NO_IPHLPAPI /* Apparently, some systems does not have proper headers for IPHLPAIP to work. * The best is to upgrade headers, but here's another, ugly workaround for * this: compile with -DNO_IPHLPAPI. */ typedef DWORD (WINAPI *GetAdaptersAddressesFunc)( ULONG Family, DWORD Flags, PVOID Reserved, PIP_ADAPTER_ADDRESSES pAdapterAddresses, PULONG pOutBufLen); static int dns_initns_iphlpapi(struct dns_ctx *ctx) { HANDLE h_iphlpapi; GetAdaptersAddressesFunc pfnGetAdAddrs; PIP_ADAPTER_ADDRESSES pAddr, pAddrBuf; PIP_ADAPTER_DNS_SERVER_ADDRESS pDnsAddr; ULONG ulOutBufLen; DWORD dwRetVal; int ret = -1; h_iphlpapi = LoadLibrary("iphlpapi.dll"); if (!h_iphlpapi) return -1; pfnGetAdAddrs = (GetAdaptersAddressesFunc) GetProcAddress(h_iphlpapi, "GetAdaptersAddresses"); if (!pfnGetAdAddrs) goto freelib; ulOutBufLen = 0; dwRetVal = pfnGetAdAddrs(AF_UNSPEC, 0, NULL, NULL, &ulOutBufLen); if (dwRetVal != ERROR_BUFFER_OVERFLOW) goto freelib; pAddrBuf = malloc(ulOutBufLen); if (!pAddrBuf) goto freelib; dwRetVal = pfnGetAdAddrs(AF_UNSPEC, 0, NULL, pAddrBuf, &ulOutBufLen); if (dwRetVal != ERROR_SUCCESS) goto freemem; for (pAddr = pAddrBuf; pAddr; pAddr = pAddr->Next) for (pDnsAddr = pAddr->FirstDnsServerAddress; pDnsAddr; pDnsAddr = pDnsAddr->Next) dns_add_serv_s(ctx, pDnsAddr->Address.lpSockaddr); ret = 0; freemem: free(pAddrBuf); freelib: FreeLibrary(h_iphlpapi); return ret; } #else /* NO_IPHLPAPI */ #define dns_initns_iphlpapi(ctx) (-1) #endif /* NO_IPHLPAPI */ static int dns_initns_registry(struct dns_ctx *ctx) { LONG res; HKEY hk; DWORD type = REG_EXPAND_SZ | REG_SZ; DWORD len; char valBuf[1024]; #define REGKEY_WINNT "SYSTEM\\CurrentControlSet\\Services\\Tcpip\\Parameters" #define REGKEY_WIN9x "SYSTEM\\CurrentControlSet\\Services\\VxD\\MSTCP" res = RegOpenKeyEx(HKEY_LOCAL_MACHINE, REGKEY_WINNT, 0, KEY_QUERY_VALUE, &hk); if (res != ERROR_SUCCESS) res = RegOpenKeyEx(HKEY_LOCAL_MACHINE, REGKEY_WIN9x, 0, KEY_QUERY_VALUE, &hk); if (res != ERROR_SUCCESS) return -1; len = sizeof(valBuf) - 1; res = RegQueryValueEx(hk, "NameServer", NULL, &type, (BYTE*)valBuf, &len); if (res != ERROR_SUCCESS || !len || !valBuf[0]) { len = sizeof(valBuf) - 1; res = RegQueryValueEx(hk, "DhcpNameServer", NULL, &type, (BYTE*)valBuf, &len); } RegCloseKey(hk); if (res != ERROR_SUCCESS || !len || !valBuf[0]) return -1; valBuf[len] = '\0'; /* nameservers are stored as a whitespace-seperate list: * "192.168.1.1 123.21.32.12" */ dns_set_serv_internal(ctx, valBuf); return 0; } #else /* !WINDOWS */ static int dns_init_resolvconf(struct dns_ctx *ctx) { char *v; char buf[2049]; /* this buffer is used to hold /etc/resolv.conf */ int has_srch = 0; /* read resolv.conf... */ { int fd = open("/etc/resolv.conf", O_RDONLY); if (fd >= 0) { int l = read(fd, buf, sizeof(buf) - 1); close(fd); buf[l < 0 ? 0 : l] = '\0'; } else buf[0] = '\0'; } if (buf[0]) { /* ...and parse it */ char *line, *nextline; line = buf; do { nextline = strchr(line, '\n'); if (nextline) *nextline++ = '\0'; v = line; while(*v && !ISSPACE(*v)) ++v; if (!*v) continue; *v++ = '\0'; while(ISSPACE(*v)) ++v; if (!*v) continue; if (strcmp(line, "domain") == 0) { dns_set_srch_internal(ctx, strtok(v, space)); has_srch = 1; } else if (strcmp(line, "search") == 0) { dns_set_srch_internal(ctx, v); has_srch = 1; } else if (strcmp(line, "nameserver") == 0) dns_add_serv(ctx, strtok(v, space)); else if (strcmp(line, "options") == 0) dns_set_opts(ctx, v); } while((line = nextline) != NULL); } buf[sizeof(buf)-1] = '\0'; /* get list of nameservers from env. vars. */ if ((v = getenv("NSCACHEIP")) != NULL || (v = getenv("NAMESERVERS")) != NULL) { strncpy(buf, v, sizeof(buf) - 1); dns_set_serv_internal(ctx, buf); } /* if $LOCALDOMAIN is set, use it for search list */ if ((v = getenv("LOCALDOMAIN")) != NULL) { strncpy(buf, v, sizeof(buf) - 1); dns_set_srch_internal(ctx, buf); has_srch = 1; } if ((v = getenv("RES_OPTIONS")) != NULL) dns_set_opts(ctx, v); /* if still no search list, use local domain name */ if (!has_srch && gethostname(buf, sizeof(buf) - 1) == 0 && (v = strchr(buf, '.')) != NULL && *++v != '\0') dns_add_srch(ctx, v); return 0; } #endif /* !WINDOWS */ int dns_init(struct dns_ctx *ctx, int do_open) { if (!ctx) ctx = &dns_defctx; dns_reset(ctx); #ifdef WINDOWS if (dns_initns_iphlpapi(ctx) != 0) dns_initns_registry(ctx); /*XXX WINDOWS: probably good to get default domain and search list too... * And options. Something is in registry. */ /*XXX WINDOWS: maybe environment variables are also useful? */ #else dns_init_resolvconf(ctx); #endif return do_open ? dns_open(ctx) : 0; } udns-0.6/udns_misc.c0000644000175000017500000000410211604616255012631 0ustar mjtmjt/* udns_misc.c miscellaneous routines Copyright (C) 2005 Michael Tokarev This file is part of UDNS library, an async DNS stub resolver. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library, in file named COPYING.LGPL; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include "udns.h" int dns_findname(const struct dns_nameval *nv, const char *name) { register const char *a, *b; for(; nv->name; ++nv) for(a = name, b = nv->name; ; ++a, ++b) if (DNS_DNUC(*a) != *b) break; else if (!*a) return nv->val; return -1; } const char *_dns_format_code(char *buf, const char *prefix, int code) { char *bp = buf; unsigned c, n; do *bp++ = DNS_DNUC(*prefix); while(*++prefix); *bp++ = '#'; if (code < 0) code = -code, *bp++ = '-'; n = 0; c = code; do ++n; while((c /= 10)); c = code; bp[n--] = '\0'; do bp[n--] = c % 10 + '0'; while((c /= 10)); return buf; } const char *dns_strerror(int err) { if (err >= 0) return "successeful completion"; switch(err) { case DNS_E_TEMPFAIL: return "temporary failure in name resolution"; case DNS_E_PROTOCOL: return "protocol error"; case DNS_E_NXDOMAIN: return "domain name does not exist"; case DNS_E_NODATA: return "valid domain but no data of requested type"; case DNS_E_NOMEM: return "out of memory"; case DNS_E_BADQUERY: return "malformed query"; default: return "unknown error"; } } const char *dns_version(void) { return UDNS_VERSION; } udns-0.6/udns_XtoX.c0000644000175000017500000000273214650626540012611 0ustar mjtmjt/* udns_XtoX.c dns_ntop() and dns_pton() routines, which are either - wrappers for inet_ntop() and inet_pton() or - reimplementations of those routines. Copyright (C) 2005 Michael Tokarev This file is part of UDNS library, an async DNS stub resolver. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library, in file named COPYING.LGPL; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #ifdef HAVE_CONFIG_H # include "config.h" #endif #include "udns.h" #ifdef HAVE_INET_PTON_NTOP #include #include #include const char *dns_ntop(int af, const void *src, char *dst, unsigned size) { return inet_ntop(af, src, dst, size); } int dns_pton(int af, const char *src, void *dst) { return inet_pton(af, src, dst); } #else #define inet_XtoX_prefix dns_ #include "inet_XtoX.c" #endif udns-0.6/udns_rr_a.c0000644000175000017500000000723211604616300012617 0ustar mjtmjt/* udns_rr_a.c parse/query A/AAAA IN records Copyright (C) 2005 Michael Tokarev This file is part of UDNS library, an async DNS stub resolver. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library, in file named COPYING.LGPL; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include #include #include #ifndef WINDOWS # include # include #endif #include "udns.h" /* here, we use common routine to parse both IPv4 and IPv6 addresses. */ /* this structure should match dns_rr_a[46] */ struct dns_rr_a { dns_rr_common(dnsa); unsigned char *dnsa_addr; }; static int dns_parse_a(dnscc_t *qdn, dnscc_t *pkt, dnscc_t *cur, dnscc_t *end, void **result, unsigned dsize) { struct dns_rr_a *ret; struct dns_parse p; struct dns_rr rr; int r; /* first, validate and count number of addresses */ dns_initparse(&p, qdn, pkt, cur, end); while((r = dns_nextrr(&p, &rr)) > 0) if (rr.dnsrr_dsz != dsize) return DNS_E_PROTOCOL; if (r < 0) return DNS_E_PROTOCOL; else if (!p.dnsp_nrr) return DNS_E_NODATA; ret = malloc(sizeof(*ret) + dsize * p.dnsp_nrr + dns_stdrr_size(&p)); if (!ret) return DNS_E_NOMEM; ret->dnsa_nrr = p.dnsp_nrr; ret->dnsa_addr = (unsigned char*)(ret+1); /* copy the RRs */ for (dns_rewind(&p, qdn), r = 0; dns_nextrr(&p, &rr); ++r) memcpy(ret->dnsa_addr + dsize * r, rr.dnsrr_dptr, dsize); dns_stdrr_finish((struct dns_rr_null *)ret, (char *)(ret->dnsa_addr + dsize * p.dnsp_nrr), &p); *result = ret; return 0; } int dns_parse_a4(dnscc_t *qdn, dnscc_t *pkt, dnscc_t *cur, dnscc_t *end, void **result) { #ifdef AF_INET assert(sizeof(struct in_addr) == 4); #endif assert(dns_get16(cur+2) == DNS_C_IN && dns_get16(cur+0) == DNS_T_A); return dns_parse_a(qdn, pkt, cur, end, result, 4); } struct dns_query * dns_submit_a4(struct dns_ctx *ctx, const char *name, int flags, dns_query_a4_fn *cbck, void *data) { return dns_submit_p(ctx, name, DNS_C_IN, DNS_T_A, flags, dns_parse_a4, (dns_query_fn*)cbck, data); } struct dns_rr_a4 * dns_resolve_a4(struct dns_ctx *ctx, const char *name, int flags) { return (struct dns_rr_a4 *) dns_resolve_p(ctx, name, DNS_C_IN, DNS_T_A, flags, dns_parse_a4); } int dns_parse_a6(dnscc_t *qdn, dnscc_t *pkt, dnscc_t *cur, dnscc_t *end, void **result) { #ifdef AF_INET6 assert(sizeof(struct in6_addr) == 16); #endif assert(dns_get16(cur+2) == DNS_C_IN && dns_get16(cur+0) == DNS_T_AAAA); return dns_parse_a(qdn, pkt, cur, end, result, 16); } struct dns_query * dns_submit_a6(struct dns_ctx *ctx, const char *name, int flags, dns_query_a6_fn *cbck, void *data) { return dns_submit_p(ctx, name, DNS_C_IN, DNS_T_AAAA, flags, dns_parse_a6, (dns_query_fn*)cbck, data); } struct dns_rr_a6 * dns_resolve_a6(struct dns_ctx *ctx, const char *name, int flags) { return (struct dns_rr_a6 *) dns_resolve_p(ctx, name, DNS_C_IN, DNS_T_AAAA, flags, dns_parse_a6); } udns-0.6/udns_rr_ptr.c0000644000175000017500000000647011604616320013211 0ustar mjtmjt/* udns_rr_ptr.c parse/query PTR records Copyright (C) 2005 Michael Tokarev This file is part of UDNS library, an async DNS stub resolver. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library, in file named COPYING.LGPL; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include #include #include "udns.h" int dns_parse_ptr(dnscc_t *qdn, dnscc_t *pkt, dnscc_t *cur, dnscc_t *end, void **result) { struct dns_rr_ptr *ret; struct dns_parse p; struct dns_rr rr; int r, l, c; char *sp; dnsc_t ptr[DNS_MAXDN]; assert(dns_get16(cur+2) == DNS_C_IN && dns_get16(cur+0) == DNS_T_PTR); /* first, validate the answer and count size of the result */ l = c = 0; dns_initparse(&p, qdn, pkt, cur, end); while((r = dns_nextrr(&p, &rr)) > 0) { cur = rr.dnsrr_dptr; r = dns_getdn(pkt, &cur, end, ptr, sizeof(ptr)); if (r <= 0 || cur != rr.dnsrr_dend) return DNS_E_PROTOCOL; l += dns_dntop_size(ptr); ++c; } if (r < 0) return DNS_E_PROTOCOL; if (!c) return DNS_E_NODATA; /* next, allocate and set up result */ ret = malloc(sizeof(*ret) + sizeof(char **) * c + l + dns_stdrr_size(&p)); if (!ret) return DNS_E_NOMEM; ret->dnsptr_nrr = c; ret->dnsptr_ptr = (char **)(ret+1); /* and 3rd, fill in result, finally */ sp = (char*)(ret->dnsptr_ptr + c); c = 0; dns_rewind(&p, qdn); while((r = dns_nextrr(&p, &rr)) > 0) { ret->dnsptr_ptr[c] = sp; cur = rr.dnsrr_dptr; dns_getdn(pkt, &cur, end, ptr, sizeof(ptr)); sp += dns_dntop(ptr, sp, DNS_MAXNAME); ++c; } dns_stdrr_finish((struct dns_rr_null *)ret, sp, &p); *result = ret; return 0; } struct dns_query * dns_submit_a4ptr(struct dns_ctx *ctx, const struct in_addr *addr, dns_query_ptr_fn *cbck, void *data) { dnsc_t dn[DNS_A4RSIZE]; dns_a4todn(addr, 0, dn, sizeof(dn)); return dns_submit_dn(ctx, dn, DNS_C_IN, DNS_T_PTR, DNS_NOSRCH, dns_parse_ptr, (dns_query_fn *)cbck, data); } struct dns_rr_ptr * dns_resolve_a4ptr(struct dns_ctx *ctx, const struct in_addr *addr) { return (struct dns_rr_ptr *) dns_resolve(ctx, dns_submit_a4ptr(ctx, addr, NULL, NULL)); } struct dns_query * dns_submit_a6ptr(struct dns_ctx *ctx, const struct in6_addr *addr, dns_query_ptr_fn *cbck, void *data) { dnsc_t dn[DNS_A6RSIZE]; dns_a6todn(addr, 0, dn, sizeof(dn)); return dns_submit_dn(ctx, dn, DNS_C_IN, DNS_T_PTR, DNS_NOSRCH, dns_parse_ptr, (dns_query_fn *)cbck, data); } struct dns_rr_ptr * dns_resolve_a6ptr(struct dns_ctx *ctx, const struct in6_addr *addr) { return (struct dns_rr_ptr *) dns_resolve(ctx, dns_submit_a6ptr(ctx, addr, NULL, NULL)); } udns-0.6/udns_rr_mx.c0000644000175000017500000000547611604616305013040 0ustar mjtmjt/* udns_rr_mx.c parse/query MX IN records Copyright (C) 2005 Michael Tokarev This file is part of UDNS library, an async DNS stub resolver. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library, in file named COPYING.LGPL; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include #include #include #include "udns.h" int dns_parse_mx(dnscc_t *qdn, dnscc_t *pkt, dnscc_t *cur, dnscc_t *end, void **result) { struct dns_rr_mx *ret; struct dns_parse p; struct dns_rr rr; int r, l; char *sp; dnsc_t mx[DNS_MAXDN]; assert(dns_get16(cur+2) == DNS_C_IN && dns_get16(cur+0) == DNS_T_MX); /* first, validate the answer and count size of the result */ l = 0; dns_initparse(&p, qdn, pkt, cur, end); while((r = dns_nextrr(&p, &rr)) > 0) { cur = rr.dnsrr_dptr + 2; r = dns_getdn(pkt, &cur, end, mx, sizeof(mx)); if (r <= 0 || cur != rr.dnsrr_dend) return DNS_E_PROTOCOL; l += dns_dntop_size(mx); } if (r < 0) return DNS_E_PROTOCOL; if (!p.dnsp_nrr) return DNS_E_NODATA; /* next, allocate and set up result */ l += dns_stdrr_size(&p); ret = malloc(sizeof(*ret) + sizeof(struct dns_mx) * p.dnsp_nrr + l); if (!ret) return DNS_E_NOMEM; ret->dnsmx_nrr = p.dnsp_nrr; ret->dnsmx_mx = (struct dns_mx *)(ret+1); /* and 3rd, fill in result, finally */ sp = (char*)(ret->dnsmx_mx + p.dnsp_nrr); for (dns_rewind(&p, qdn), r = 0; dns_nextrr(&p, &rr); ++r) { ret->dnsmx_mx[r].name = sp; cur = rr.dnsrr_dptr; ret->dnsmx_mx[r].priority = dns_get16(cur); cur += 2; dns_getdn(pkt, &cur, end, mx, sizeof(mx)); sp += dns_dntop(mx, sp, DNS_MAXNAME); } dns_stdrr_finish((struct dns_rr_null *)ret, sp, &p); *result = ret; return 0; } struct dns_query * dns_submit_mx(struct dns_ctx *ctx, const char *name, int flags, dns_query_mx_fn *cbck, void *data) { return dns_submit_p(ctx, name, DNS_C_IN, DNS_T_MX, flags, dns_parse_mx, (dns_query_fn *)cbck, data); } struct dns_rr_mx * dns_resolve_mx(struct dns_ctx *ctx, const char *name, int flags) { return (struct dns_rr_mx *) dns_resolve_p(ctx, name, DNS_C_IN, DNS_T_MX, flags, dns_parse_mx); } udns-0.6/udns_rr_txt.c0000644000175000017500000000556411604616333013232 0ustar mjtmjt/* udns_rr_txt.c parse/query TXT records Copyright (C) 2005 Michael Tokarev This file is part of UDNS library, an async DNS stub resolver. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library, in file named COPYING.LGPL; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include #include #include #include "udns.h" int dns_parse_txt(dnscc_t *qdn, dnscc_t *pkt, dnscc_t *cur, dnscc_t *end, void **result) { struct dns_rr_txt *ret; struct dns_parse p; struct dns_rr rr; int r, l; dnsc_t *sp; dnscc_t *cp, *ep; assert(dns_get16(cur+0) == DNS_T_TXT); /* first, validate the answer and count size of the result */ l = 0; dns_initparse(&p, qdn, pkt, cur, end); while((r = dns_nextrr(&p, &rr)) > 0) { cp = rr.dnsrr_dptr; ep = rr.dnsrr_dend; while(cp < ep) { r = *cp++; if (cp + r > ep) return DNS_E_PROTOCOL; l += r; cp += r; } } if (r < 0) return DNS_E_PROTOCOL; if (!p.dnsp_nrr) return DNS_E_NODATA; /* next, allocate and set up result */ l += (sizeof(struct dns_txt) + 1) * p.dnsp_nrr + dns_stdrr_size(&p); ret = malloc(sizeof(*ret) + l); if (!ret) return DNS_E_NOMEM; ret->dnstxt_nrr = p.dnsp_nrr; ret->dnstxt_txt = (struct dns_txt *)(ret+1); /* and 3rd, fill in result, finally */ sp = (dnsc_t*)(ret->dnstxt_txt + p.dnsp_nrr); for(dns_rewind(&p, qdn), r = 0; dns_nextrr(&p, &rr) > 0; ++r) { ret->dnstxt_txt[r].txt = sp; cp = rr.dnsrr_dptr; ep = rr.dnsrr_dend; while(cp < ep) { l = *cp++; memcpy(sp, cp, l); sp += l; cp += l; } ret->dnstxt_txt[r].len = sp - ret->dnstxt_txt[r].txt; *sp++ = '\0'; } dns_stdrr_finish((struct dns_rr_null *)ret, (char*)sp, &p); *result = ret; return 0; } struct dns_query * dns_submit_txt(struct dns_ctx *ctx, const char *name, int qcls, int flags, dns_query_txt_fn *cbck, void *data) { return dns_submit_p(ctx, name, qcls, DNS_T_TXT, flags, dns_parse_txt, (dns_query_fn *)cbck, data); } struct dns_rr_txt * dns_resolve_txt(struct dns_ctx *ctx, const char *name, int qcls, int flags) { return (struct dns_rr_txt *) dns_resolve_p(ctx, name, qcls, DNS_T_TXT, flags, dns_parse_txt); } udns-0.6/udns_bl.c0000644000175000017500000001213211604616206012271 0ustar mjtmjt/* udns_bl.c DNSBL stuff Copyright (C) 2005 Michael Tokarev This file is part of UDNS library, an async DNS stub resolver. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library, in file named COPYING.LGPL; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include "udns.h" #ifndef NULL # define NULL 0 #endif struct dns_query * dns_submit_a4dnsbl(struct dns_ctx *ctx, const struct in_addr *addr, const char *dnsbl, dns_query_a4_fn *cbck, void *data) { dnsc_t dn[DNS_MAXDN]; if (dns_a4ptodn(addr, dnsbl, dn, sizeof(dn)) <= 0) { dns_setstatus(ctx, DNS_E_BADQUERY); return NULL; } return dns_submit_dn(ctx, dn, DNS_C_IN, DNS_T_A, DNS_NOSRCH, dns_parse_a4, (dns_query_fn*)cbck, data); } struct dns_query * dns_submit_a4dnsbl_txt(struct dns_ctx *ctx, const struct in_addr *addr, const char *dnsbl, dns_query_txt_fn *cbck, void *data) { dnsc_t dn[DNS_MAXDN]; if (dns_a4ptodn(addr, dnsbl, dn, sizeof(dn)) <= 0) { dns_setstatus(ctx, DNS_E_BADQUERY); return NULL; } return dns_submit_dn(ctx, dn, DNS_C_IN, DNS_T_TXT, DNS_NOSRCH, dns_parse_txt, (dns_query_fn*)cbck, data); } struct dns_rr_a4 * dns_resolve_a4dnsbl(struct dns_ctx *ctx, const struct in_addr *addr, const char *dnsbl) { return (struct dns_rr_a4 *) dns_resolve(ctx, dns_submit_a4dnsbl(ctx, addr, dnsbl, 0, 0)); } struct dns_rr_txt * dns_resolve_a4dnsbl_txt(struct dns_ctx *ctx, const struct in_addr *addr, const char *dnsbl) { return (struct dns_rr_txt *) dns_resolve(ctx, dns_submit_a4dnsbl_txt(ctx, addr, dnsbl, 0, 0)); } struct dns_query * dns_submit_a6dnsbl(struct dns_ctx *ctx, const struct in6_addr *addr, const char *dnsbl, dns_query_a4_fn *cbck, void *data) { dnsc_t dn[DNS_MAXDN]; if (dns_a6ptodn(addr, dnsbl, dn, sizeof(dn)) <= 0) { dns_setstatus(ctx, DNS_E_BADQUERY); return NULL; } return dns_submit_dn(ctx, dn, DNS_C_IN, DNS_T_A, DNS_NOSRCH, dns_parse_a4, (dns_query_fn*)cbck, data); } struct dns_query * dns_submit_a6dnsbl_txt(struct dns_ctx *ctx, const struct in6_addr *addr, const char *dnsbl, dns_query_txt_fn *cbck, void *data) { dnsc_t dn[DNS_MAXDN]; if (dns_a6ptodn(addr, dnsbl, dn, sizeof(dn)) <= 0) { dns_setstatus(ctx, DNS_E_BADQUERY); return NULL; } return dns_submit_dn(ctx, dn, DNS_C_IN, DNS_T_TXT, DNS_NOSRCH, dns_parse_txt, (dns_query_fn*)cbck, data); } struct dns_rr_a4 * dns_resolve_a6dnsbl(struct dns_ctx *ctx, const struct in6_addr *addr, const char *dnsbl) { return (struct dns_rr_a4 *) dns_resolve(ctx, dns_submit_a6dnsbl(ctx, addr, dnsbl, 0, 0)); } struct dns_rr_txt * dns_resolve_a6dnsbl_txt(struct dns_ctx *ctx, const struct in6_addr *addr, const char *dnsbl) { return (struct dns_rr_txt *) dns_resolve(ctx, dns_submit_a6dnsbl_txt(ctx, addr, dnsbl, 0, 0)); } static int dns_rhsbltodn(const char *name, const char *rhsbl, dnsc_t dn[DNS_MAXDN]) { int l = dns_sptodn(name, dn, DNS_MAXDN); if (l <= 0) return 0; l = dns_sptodn(rhsbl, dn+l-1, DNS_MAXDN-l+1); if (l <= 0) return 0; return 1; } struct dns_query * dns_submit_rhsbl(struct dns_ctx *ctx, const char *name, const char *rhsbl, dns_query_a4_fn *cbck, void *data) { dnsc_t dn[DNS_MAXDN]; if (!dns_rhsbltodn(name, rhsbl, dn)) { dns_setstatus(ctx, DNS_E_BADQUERY); return NULL; } return dns_submit_dn(ctx, dn, DNS_C_IN, DNS_T_A, DNS_NOSRCH, dns_parse_a4, (dns_query_fn*)cbck, data); } struct dns_query * dns_submit_rhsbl_txt(struct dns_ctx *ctx, const char *name, const char *rhsbl, dns_query_txt_fn *cbck, void *data) { dnsc_t dn[DNS_MAXDN]; if (!dns_rhsbltodn(name, rhsbl, dn)) { dns_setstatus(ctx, DNS_E_BADQUERY); return NULL; } return dns_submit_dn(ctx, dn, DNS_C_IN, DNS_T_TXT, DNS_NOSRCH, dns_parse_txt, (dns_query_fn*)cbck, data); } struct dns_rr_a4 * dns_resolve_rhsbl(struct dns_ctx *ctx, const char *name, const char *rhsbl) { return (struct dns_rr_a4*) dns_resolve(ctx, dns_submit_rhsbl(ctx, name, rhsbl, 0, 0)); } struct dns_rr_txt * dns_resolve_rhsbl_txt(struct dns_ctx *ctx, const char *name, const char *rhsbl) { return (struct dns_rr_txt*) dns_resolve(ctx, dns_submit_rhsbl_txt(ctx, name, rhsbl, 0, 0)); } udns-0.6/udns_rr_srv.c0000644000175000017500000001131511604616353013216 0ustar mjtmjt/* udns_rr_srv.c parse/query SRV IN (rfc2782) records Copyright (C) 2005 Michael Tokarev This file is part of UDNS library, an async DNS stub resolver. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library, in file named COPYING.LGPL; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA Copyright 2005 Thadeu Lima de Souza Cascardo 2005-09-11: Changed MX parser file into a SRV parser file */ #include #include #include #include "udns.h" int dns_parse_srv(dnscc_t *qdn, dnscc_t *pkt, dnscc_t *cur, dnscc_t *end, void **result) { struct dns_rr_srv *ret; struct dns_parse p; struct dns_rr rr; int r, l; char *sp; dnsc_t srv[DNS_MAXDN]; assert(dns_get16(cur+2) == DNS_C_IN && dns_get16(cur+0) == DNS_T_SRV); /* first, validate the answer and count size of the result */ l = 0; dns_initparse(&p, qdn, pkt, cur, end); while((r = dns_nextrr(&p, &rr)) > 0) { cur = rr.dnsrr_dptr + 6; r = dns_getdn(pkt, &cur, end, srv, sizeof(srv)); if (r <= 0 || cur != rr.dnsrr_dend) return DNS_E_PROTOCOL; l += dns_dntop_size(srv); } if (r < 0) return DNS_E_PROTOCOL; if (!p.dnsp_nrr) return DNS_E_NODATA; /* next, allocate and set up result */ l += dns_stdrr_size(&p); ret = malloc(sizeof(*ret) + sizeof(struct dns_srv) * p.dnsp_nrr + l); if (!ret) return DNS_E_NOMEM; ret->dnssrv_nrr = p.dnsp_nrr; ret->dnssrv_srv = (struct dns_srv *)(ret+1); /* and 3rd, fill in result, finally */ sp = (char*)(ret->dnssrv_srv + p.dnsp_nrr); for (dns_rewind(&p, qdn), r = 0; dns_nextrr(&p, &rr); ++r) { ret->dnssrv_srv[r].name = sp; cur = rr.dnsrr_dptr; ret->dnssrv_srv[r].priority = dns_get16(cur); ret->dnssrv_srv[r].weight = dns_get16(cur+2); ret->dnssrv_srv[r].port = dns_get16(cur+4); cur += 6; dns_getdn(pkt, &cur, end, srv, sizeof(srv)); sp += dns_dntop(srv, sp, DNS_MAXNAME); } dns_stdrr_finish((struct dns_rr_null *)ret, sp, &p); *result = ret; return 0; } /* Add a single service or proto name prepending an undescore (_), * according to rfc2782 rules. * Return 0 or the label length. * Routing assumes dn holds enouth space for a single DN label. */ static int add_sname(dnsc_t *dn, const char *sn) { int l = dns_ptodn(sn, 0, dn + 1, DNS_MAXLABEL-1, NULL); if (l <= 1 || l - 2 != dn[1]) /* Should we really check if sn is exactly one label? Do we care? */ return 0; dn[0] = l - 1; dn[1] = '_'; return l; } /* Construct a domain name for SRV query from the given name, service and proto. * The code allows any combinations of srv and proto (both are non-NULL, * both NULL, or either one is non-NULL). Whenever it makes any sense or not * is left as an exercise to programmer. * Return negative value on error (malformed query) or addition query flag(s). */ static int build_srv_dn(dnsc_t *dn, const char *name, const char *srv, const char *proto) { int p = 0, l, isabs; if (srv) { l = add_sname(dn + p, srv); if (!l) return -1; p += l; } if (proto) { l = add_sname(dn + p, proto); if (!l) return -1; p += l; } l = dns_ptodn(name, 0, dn + p, DNS_MAXDN - p, &isabs); if (l < 0) return -1; return isabs ? DNS_NOSRCH : 0; } struct dns_query * dns_submit_srv(struct dns_ctx *ctx, const char *name, const char *srv, const char *proto, int flags, dns_query_srv_fn *cbck, void *data) { dnsc_t dn[DNS_MAXDN]; int r = build_srv_dn(dn, name, srv, proto); if (r < 0) { dns_setstatus (ctx, DNS_E_BADQUERY); return NULL; } return dns_submit_dn(ctx, dn, DNS_C_IN, DNS_T_SRV, flags | r, dns_parse_srv, (dns_query_fn *)cbck, data); } struct dns_rr_srv * dns_resolve_srv(struct dns_ctx *ctx, const char *name, const char *srv, const char *proto, int flags) { dnsc_t dn[DNS_MAXDN]; int r = build_srv_dn(dn, name, srv, proto); if (r < 0) { dns_setstatus(ctx, DNS_E_BADQUERY); return NULL; } return (struct dns_rr_srv *) dns_resolve_dn(ctx, dn, DNS_C_IN, DNS_T_SRV, flags | r, dns_parse_srv); } udns-0.6/udns_rr_naptr.c0000644000175000017500000000760711604616313013535 0ustar mjtmjt/* udns_rr_naptr.c parse/query NAPTR IN records Copyright (C) 2005 Michael Tokarev Copyright (C) 2006 Mikael Magnusson This file is part of UDNS library, an async DNS stub resolver. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library, in file named COPYING.LGPL; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include #include #include #include "udns.h" /* Get a single string for NAPTR record, pretty much like a DN label. * String length is in first byte in *cur, so it can't be >255. */ static int dns_getstr(dnscc_t **cur, dnscc_t *ep, char *buf) { unsigned l; dnscc_t *cp = *cur; l = *cp++; if (cp + l > ep) return DNS_E_PROTOCOL; if (buf) { memcpy(buf, cp, l); buf[l] = '\0'; } cp += l; *cur = cp; return l + 1; } int dns_parse_naptr(dnscc_t *qdn, dnscc_t *pkt, dnscc_t *cur, dnscc_t *end, void **result) { struct dns_rr_naptr *ret; struct dns_parse p; struct dns_rr rr; int r, l; char *sp; dnsc_t dn[DNS_MAXDN]; assert(dns_get16(cur+2) == DNS_C_IN && dns_get16(cur+0) == DNS_T_NAPTR); /* first, validate the answer and count size of the result */ l = 0; dns_initparse(&p, qdn, pkt, cur, end); while((r = dns_nextrr(&p, &rr)) > 0) { int i; dnscc_t *ep = rr.dnsrr_dend; /* first 4 bytes: order & preference */ cur = rr.dnsrr_dptr + 4; /* flags, services and regexp */ for (i = 0; i < 3; i++) { r = dns_getstr(&cur, ep, NULL); if (r < 0) return r; l += r; } /* replacement */ r = dns_getdn(pkt, &cur, end, dn, sizeof(dn)); if (r <= 0 || cur != rr.dnsrr_dend) return DNS_E_PROTOCOL; l += dns_dntop_size(dn); } if (r < 0) return DNS_E_PROTOCOL; if (!p.dnsp_nrr) return DNS_E_NODATA; /* next, allocate and set up result */ l += dns_stdrr_size(&p); ret = malloc(sizeof(*ret) + sizeof(struct dns_naptr) * p.dnsp_nrr + l); if (!ret) return DNS_E_NOMEM; ret->dnsnaptr_nrr = p.dnsp_nrr; ret->dnsnaptr_naptr = (struct dns_naptr *)(ret+1); /* and 3rd, fill in result, finally */ sp = (char*)(&ret->dnsnaptr_naptr[p.dnsp_nrr]); for (dns_rewind(&p, qdn), r = 0; dns_nextrr(&p, &rr); ++r) { cur = rr.dnsrr_dptr; ret->dnsnaptr_naptr[r].order = dns_get16(cur); cur += 2; ret->dnsnaptr_naptr[r].preference = dns_get16(cur); cur += 2; sp += dns_getstr(&cur, end, (ret->dnsnaptr_naptr[r].flags = sp)); sp += dns_getstr(&cur, end, (ret->dnsnaptr_naptr[r].service = sp)); sp += dns_getstr(&cur, end, (ret->dnsnaptr_naptr[r].regexp = sp)); dns_getdn(pkt, &cur, end, dn, sizeof(dn)); sp += dns_dntop(dn, (ret->dnsnaptr_naptr[r].replacement = sp), DNS_MAXNAME); } dns_stdrr_finish((struct dns_rr_null *)ret, sp, &p); *result = ret; return 0; } struct dns_query * dns_submit_naptr(struct dns_ctx *ctx, const char *name, int flags, dns_query_naptr_fn *cbck, void *data) { return dns_submit_p(ctx, name, DNS_C_IN, DNS_T_NAPTR, flags, dns_parse_naptr, (dns_query_fn *)cbck, data); } struct dns_rr_naptr * dns_resolve_naptr(struct dns_ctx *ctx, const char *name, int flags) { return (struct dns_rr_naptr *) dns_resolve_p(ctx, name, DNS_C_IN, DNS_T_NAPTR, flags, dns_parse_naptr); } udns-0.6/udns_codes.c0000644000175000017500000001464114650630532013002 0ustar mjtmjt/* Automatically generated. */ #include "udns.h" const struct dns_nameval dns_typetab[] = { {DNS_T_INVALID,"INVALID"}, {DNS_T_A,"A"}, {DNS_T_NS,"NS"}, {DNS_T_MD,"MD"}, {DNS_T_MF,"MF"}, {DNS_T_CNAME,"CNAME"}, {DNS_T_SOA,"SOA"}, {DNS_T_MB,"MB"}, {DNS_T_MG,"MG"}, {DNS_T_MR,"MR"}, {DNS_T_NULL,"NULL"}, {DNS_T_WKS,"WKS"}, {DNS_T_PTR,"PTR"}, {DNS_T_HINFO,"HINFO"}, {DNS_T_MINFO,"MINFO"}, {DNS_T_MX,"MX"}, {DNS_T_TXT,"TXT"}, {DNS_T_RP,"RP"}, {DNS_T_AFSDB,"AFSDB"}, {DNS_T_X25,"X25"}, {DNS_T_ISDN,"ISDN"}, {DNS_T_RT,"RT"}, {DNS_T_NSAP,"NSAP"}, {DNS_T_NSAP_PTR,"NSAP_PTR"}, {DNS_T_SIG,"SIG"}, {DNS_T_KEY,"KEY"}, {DNS_T_PX,"PX"}, {DNS_T_GPOS,"GPOS"}, {DNS_T_AAAA,"AAAA"}, {DNS_T_LOC,"LOC"}, {DNS_T_NXT,"NXT"}, {DNS_T_EID,"EID"}, {DNS_T_NIMLOC,"NIMLOC"}, {DNS_T_SRV,"SRV"}, {DNS_T_ATMA,"ATMA"}, {DNS_T_NAPTR,"NAPTR"}, {DNS_T_KX,"KX"}, {DNS_T_CERT,"CERT"}, {DNS_T_A6,"A6"}, {DNS_T_DNAME,"DNAME"}, {DNS_T_SINK,"SINK"}, {DNS_T_OPT,"OPT"}, {DNS_T_DS,"DS"}, {DNS_T_SSHFP,"SSHFP"}, {DNS_T_IPSECKEY,"IPSECKEY"}, {DNS_T_RRSIG,"RRSIG"}, {DNS_T_NSEC,"NSEC"}, {DNS_T_DNSKEY,"DNSKEY"}, {DNS_T_DHCID,"DHCID"}, {DNS_T_NSEC3,"NSEC3"}, {DNS_T_NSEC3PARAMS,"NSEC3PARAMS"}, {DNS_T_TALINK,"TALINK"}, {DNS_T_SPF,"SPF"}, {DNS_T_UINFO,"UINFO"}, {DNS_T_UID,"UID"}, {DNS_T_GID,"GID"}, {DNS_T_UNSPEC,"UNSPEC"}, {DNS_T_TSIG,"TSIG"}, {DNS_T_IXFR,"IXFR"}, {DNS_T_AXFR,"AXFR"}, {DNS_T_MAILB,"MAILB"}, {DNS_T_MAILA,"MAILA"}, {DNS_T_ANY,"ANY"}, {DNS_T_ZXFR,"ZXFR"}, {DNS_T_DLV,"DLV"}, {DNS_T_MAX,"MAX"}, {0,0}}; const char *dns_typename(enum dns_type code) { static char nm[20]; switch(code) { case DNS_T_INVALID: return dns_typetab[0].name; case DNS_T_A: return dns_typetab[1].name; case DNS_T_NS: return dns_typetab[2].name; case DNS_T_MD: return dns_typetab[3].name; case DNS_T_MF: return dns_typetab[4].name; case DNS_T_CNAME: return dns_typetab[5].name; case DNS_T_SOA: return dns_typetab[6].name; case DNS_T_MB: return dns_typetab[7].name; case DNS_T_MG: return dns_typetab[8].name; case DNS_T_MR: return dns_typetab[9].name; case DNS_T_NULL: return dns_typetab[10].name; case DNS_T_WKS: return dns_typetab[11].name; case DNS_T_PTR: return dns_typetab[12].name; case DNS_T_HINFO: return dns_typetab[13].name; case DNS_T_MINFO: return dns_typetab[14].name; case DNS_T_MX: return dns_typetab[15].name; case DNS_T_TXT: return dns_typetab[16].name; case DNS_T_RP: return dns_typetab[17].name; case DNS_T_AFSDB: return dns_typetab[18].name; case DNS_T_X25: return dns_typetab[19].name; case DNS_T_ISDN: return dns_typetab[20].name; case DNS_T_RT: return dns_typetab[21].name; case DNS_T_NSAP: return dns_typetab[22].name; case DNS_T_NSAP_PTR: return dns_typetab[23].name; case DNS_T_SIG: return dns_typetab[24].name; case DNS_T_KEY: return dns_typetab[25].name; case DNS_T_PX: return dns_typetab[26].name; case DNS_T_GPOS: return dns_typetab[27].name; case DNS_T_AAAA: return dns_typetab[28].name; case DNS_T_LOC: return dns_typetab[29].name; case DNS_T_NXT: return dns_typetab[30].name; case DNS_T_EID: return dns_typetab[31].name; case DNS_T_NIMLOC: return dns_typetab[32].name; case DNS_T_SRV: return dns_typetab[33].name; case DNS_T_ATMA: return dns_typetab[34].name; case DNS_T_NAPTR: return dns_typetab[35].name; case DNS_T_KX: return dns_typetab[36].name; case DNS_T_CERT: return dns_typetab[37].name; case DNS_T_A6: return dns_typetab[38].name; case DNS_T_DNAME: return dns_typetab[39].name; case DNS_T_SINK: return dns_typetab[40].name; case DNS_T_OPT: return dns_typetab[41].name; case DNS_T_DS: return dns_typetab[42].name; case DNS_T_SSHFP: return dns_typetab[43].name; case DNS_T_IPSECKEY: return dns_typetab[44].name; case DNS_T_RRSIG: return dns_typetab[45].name; case DNS_T_NSEC: return dns_typetab[46].name; case DNS_T_DNSKEY: return dns_typetab[47].name; case DNS_T_DHCID: return dns_typetab[48].name; case DNS_T_NSEC3: return dns_typetab[49].name; case DNS_T_NSEC3PARAMS: return dns_typetab[50].name; case DNS_T_TALINK: return dns_typetab[51].name; case DNS_T_SPF: return dns_typetab[52].name; case DNS_T_UINFO: return dns_typetab[53].name; case DNS_T_UID: return dns_typetab[54].name; case DNS_T_GID: return dns_typetab[55].name; case DNS_T_UNSPEC: return dns_typetab[56].name; case DNS_T_TSIG: return dns_typetab[57].name; case DNS_T_IXFR: return dns_typetab[58].name; case DNS_T_AXFR: return dns_typetab[59].name; case DNS_T_MAILB: return dns_typetab[60].name; case DNS_T_MAILA: return dns_typetab[61].name; case DNS_T_ANY: return dns_typetab[62].name; case DNS_T_ZXFR: return dns_typetab[63].name; case DNS_T_DLV: return dns_typetab[64].name; case DNS_T_MAX: return dns_typetab[65].name; } return _dns_format_code(nm,"type",code); } const struct dns_nameval dns_classtab[] = { {DNS_C_INVALID,"INVALID"}, {DNS_C_IN,"IN"}, {DNS_C_CH,"CH"}, {DNS_C_HS,"HS"}, {DNS_C_ANY,"ANY"}, {0,0}}; const char *dns_classname(enum dns_class code) { static char nm[20]; switch(code) { case DNS_C_INVALID: return dns_classtab[0].name; case DNS_C_IN: return dns_classtab[1].name; case DNS_C_CH: return dns_classtab[2].name; case DNS_C_HS: return dns_classtab[3].name; case DNS_C_ANY: return dns_classtab[4].name; } return _dns_format_code(nm,"class",code); } const struct dns_nameval dns_rcodetab[] = { {DNS_R_NOERROR,"NOERROR"}, {DNS_R_FORMERR,"FORMERR"}, {DNS_R_SERVFAIL,"SERVFAIL"}, {DNS_R_NXDOMAIN,"NXDOMAIN"}, {DNS_R_NOTIMPL,"NOTIMPL"}, {DNS_R_REFUSED,"REFUSED"}, {DNS_R_YXDOMAIN,"YXDOMAIN"}, {DNS_R_YXRRSET,"YXRRSET"}, {DNS_R_NXRRSET,"NXRRSET"}, {DNS_R_NOTAUTH,"NOTAUTH"}, {DNS_R_NOTZONE,"NOTZONE"}, {DNS_R_BADSIG,"BADSIG"}, {DNS_R_BADKEY,"BADKEY"}, {DNS_R_BADTIME,"BADTIME"}, {0,0}}; const char *dns_rcodename(enum dns_rcode code) { static char nm[20]; switch(code) { case DNS_R_NOERROR: return dns_rcodetab[0].name; case DNS_R_FORMERR: return dns_rcodetab[1].name; case DNS_R_SERVFAIL: return dns_rcodetab[2].name; case DNS_R_NXDOMAIN: return dns_rcodetab[3].name; case DNS_R_NOTIMPL: return dns_rcodetab[4].name; case DNS_R_REFUSED: return dns_rcodetab[5].name; case DNS_R_YXDOMAIN: return dns_rcodetab[6].name; case DNS_R_YXRRSET: return dns_rcodetab[7].name; case DNS_R_NXRRSET: return dns_rcodetab[8].name; case DNS_R_NOTAUTH: return dns_rcodetab[9].name; case DNS_R_NOTZONE: return dns_rcodetab[10].name; case DNS_R_BADSIG: return dns_rcodetab[11].name; case DNS_R_BADKEY: return dns_rcodetab[12].name; case DNS_R_BADTIME: return dns_rcodetab[13].name; } return _dns_format_code(nm,"rcode",code); } udns-0.6/udns_jran.c0000644000175000017500000000275111604616247012641 0ustar mjtmjt/* udns_jran.c: small non-cryptographic random number generator * taken from http://burtleburtle.net/bob/rand/smallprng.html * by Bob Jenkins, Public domain. */ #include "udns.h" #define rot32(x,k) (((x) << (k)) | ((x) >> (32-(k)))) #define rot64(x,k) (((x) << (k)) | ((x) >> (64-(k)))) #define tr32(x) ((x)&0xffffffffu) unsigned udns_jranval(struct udns_jranctx *x) { /* This routine can be made to work with either 32 or 64bit words - * if JRAN_32_64 is defined when compiling the file. * We use if() instead of #if since there's no good * portable way to check sizeof() in preprocessor without * introducing some ugly configure-time checks. * Most compilers will optimize the wrong branches away anyway. * By default it assumes 32bit integers */ #ifdef JRAN_32_64 if (sizeof(unsigned) == 4) { #endif unsigned e = tr32(x->a - rot32(x->b, 27)); x->a = tr32(x->b ^ rot32(x->c, 17)); x->b = tr32(x->c + x->d); x->c = tr32(x->d + e); x->d = tr32(e + x->a); #ifdef JRAN_32_64 } else if (sizeof(unsigned) == 8) { /* assuming it's 64bits */ unsigned e = x->a - rot64(x->b, 7); x->a = x->b ^ rot64(x->c, 13); x->b = x->c + rot64(x->d, 37); x->c = x->d + e; x->d = e + x->a; } else { unsigned e = 0; x->d = 1/e; /* bail */ } #endif return x->d; } void udns_jraninit(struct udns_jranctx *x, unsigned seed) { unsigned i; x->a = 0xf1ea5eed; x->b = x->c = x->d = seed; for (i = 0; i < 20; ++i) (void)udns_jranval(x); } udns-0.6/dnsget.c0000644000175000017500000005216714650627113012146 0ustar mjtmjt/* dnsget.c simple host/dig-like application using UDNS library Copyright (C) 2005 Michael Tokarev This file is part of UDNS library, an async DNS stub resolver. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library, in file named COPYING.LGPL; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #ifdef HAVE_CONFIG_H # include "config.h" #endif #ifdef WINDOWS #include #include #else #include #include #include #include #include #endif #include #include #include #include #include #include #include "udns.h" #ifndef HAVE_GETOPT # include "getopt.c" #endif #ifndef AF_INET6 # define AF_INET6 10 #endif static char *progname; static int verbose = 1; static int errors; static int notfound; /* verbosity level: * <0 - bare result * 0 - bare result and error messages * 1 - readable result * 2 - received packet contents and `trying ...' stuff * 3 - sent and received packet contents */ static void die(int errnum, const char *fmt, ...) { va_list ap; fprintf(stderr, "%s: ", progname); va_start(ap, fmt); vfprintf(stderr, fmt, ap); va_end(ap); if (errnum) fprintf(stderr, ": %s\n", strerror(errnum)); else putc('\n', stderr); fflush(stderr); exit(1); } static const char *dns_xntop(int af, const void *src) { static char buf[6*5+4*4]; return dns_ntop(af, src, buf, sizeof(buf)); } struct query { const char *name; /* original query string */ unsigned char *dn; /* the DN being looked up */ enum dns_type qtyp; /* type of the query */ }; static void query_free(struct query *q) { free(q->dn); free(q); } static struct query * query_new(const char *name, const unsigned char *dn, enum dns_type qtyp) { struct query *q = malloc(sizeof(*q)); unsigned l = dns_dnlen(dn); unsigned char *cdn = malloc(l); if (!q || !cdn) die(0, "out of memory"); memcpy(cdn, dn, l); q->name = name; q->dn = cdn; q->qtyp = qtyp; return q; } static enum dns_class qcls = DNS_C_IN; static void dnserror(struct query *q, int errnum) { if (verbose >= 0) fprintf(stderr, "%s: unable to lookup %s record for %s: %s\n", progname, dns_typename(q->qtyp), dns_dntosp(q->dn), dns_strerror(errnum)); if (errnum == DNS_E_NXDOMAIN || errnum == DNS_E_NODATA) ++notfound; else ++errors; query_free(q); } static const unsigned char * printtxt(const unsigned char *c) { unsigned n = *c++; const unsigned char *e = c + n; if (verbose > 0) while(c < e) { if (*c < ' ' || *c >= 127) printf("\\%03u", *c); else if (*c == '\\' || *c == '"') printf("\\%c", *c); else putchar(*c); ++c; } else fwrite(c, n, 1, stdout); return e; } static void printhex(const unsigned char *c, const unsigned char *e) { while(c < e) printf("%02x", *c++); } static unsigned char to_b64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; static void printb64(const unsigned char *c, const unsigned char *e) { while(c < e) { putchar(to_b64[c[0] >> 2]); if (c+1 < e) { putchar(to_b64[(c[0] & 0x3) << 4 | c[1] >> 4]); if (c+2 < e) { putchar(to_b64[(c[1] & 0xf) << 2 | c[2] >> 6]); putchar(to_b64[c[2] & 0x3f]); } else { putchar(to_b64[(c[1] & 0xf) << 2]); putchar('='); break; } } else { putchar(to_b64[(c[0] & 0x3) << 4]); putchar('='); putchar('='); break; } c += 3; } } static void printdate(time_t time) { struct tm *tm = gmtime(&time); printf("%04d%02d%02d%02d%02d%02d", tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec); } static void printrr(const struct dns_parse *p, struct dns_rr *rr) { const unsigned char *pkt = p->dnsp_pkt; const unsigned char *end = p->dnsp_end; const unsigned char *dptr = rr->dnsrr_dptr; const unsigned char *dend = rr->dnsrr_dend; unsigned char *dn = rr->dnsrr_dn; const unsigned char *c; unsigned n; if (verbose > 0) { if (verbose > 1) { if (!p->dnsp_rrl && !rr->dnsrr_dn[0] && rr->dnsrr_typ == DNS_T_OPT) { printf(";EDNS%d OPT record (UDPsize: %d, ERcode: %d, Flags: 0x%02x): %d bytes\n", (rr->dnsrr_ttl>>16) & 0xff, /* version */ rr->dnsrr_cls, /* udp size */ (rr->dnsrr_ttl>>24) & 0xff, /* extended rcode */ rr->dnsrr_ttl & 0xffff, /* flags */ rr->dnsrr_dsz); return; } n = printf("%s.", dns_dntosp(rr->dnsrr_dn)); printf("%s%u\t%s\t%s\t", n > 15 ? "\t" : n > 7 ? "\t\t" : "\t\t\t", rr->dnsrr_ttl, dns_classname(rr->dnsrr_cls), dns_typename(rr->dnsrr_typ)); } else printf("%s. %s ", dns_dntosp(rr->dnsrr_dn), dns_typename(rr->dnsrr_typ)); } switch(rr->dnsrr_typ) { case DNS_T_CNAME: case DNS_T_PTR: case DNS_T_NS: case DNS_T_MB: case DNS_T_MD: case DNS_T_MF: case DNS_T_MG: case DNS_T_MR: if (dns_getdn(pkt, &dptr, end, dn, DNS_MAXDN) <= 0) goto xperr; printf("%s.", dns_dntosp(dn)); break; case DNS_T_A: if (rr->dnsrr_dsz != 4) goto xperr; printf("%d.%d.%d.%d", dptr[0], dptr[1], dptr[2], dptr[3]); break; case DNS_T_AAAA: if (rr->dnsrr_dsz != 16) goto xperr; printf("%s", dns_xntop(AF_INET6, dptr)); break; case DNS_T_MX: c = dptr + 2; if (dns_getdn(pkt, &c, end, dn, DNS_MAXDN) <= 0 || c != dend) goto xperr; printf("%d %s.", dns_get16(dptr), dns_dntosp(dn)); break; case DNS_T_TXT: /* first verify it */ for(c = dptr; c < dend; c += n) { n = *c++; if (c + n > dend) goto xperr; } c = dptr; n = 0; while (c < dend) { if (verbose > 0) printf(n++ ? "\" \"":"\""); c = printtxt(c); } if (verbose > 0) putchar('"'); break; case DNS_T_HINFO: /* CPU, OS */ c = dptr; n = *c++; if ((c += n) >= dend) goto xperr; n = *c++; if ((c += n) != dend) goto xperr; c = dptr; if (verbose > 0) putchar('"'); c = printtxt(c); if (verbose > 0) printf("\" \""); else putchar(' '); printtxt(c); if (verbose > 0) putchar('"'); break; case DNS_T_WKS: c = dptr; if (dptr + 4 + 2 >= end) goto xperr; printf("%s %d", dns_xntop(AF_INET, dptr), dptr[4]); c = dptr + 5; for (n = 0; c < dend; ++c, n += 8) { if (*c) { unsigned b; for (b = 0; b < 8; ++b) if (*c & (1 << (7-b))) printf(" %d", n + b); } } break; case DNS_T_SRV: /* prio weight port targetDN */ c = dptr; c += 2 + 2 + 2; if (dns_getdn(pkt, &c, end, dn, DNS_MAXDN) <= 0 || c != dend) goto xperr; c = dptr; printf("%d %d %d %s.", dns_get16(c+0), dns_get16(c+2), dns_get16(c+4), dns_dntosp(dn)); break; case DNS_T_NAPTR: /* order pref flags serv regexp repl */ c = dptr; c += 4; /* order, pref */ for (n = 0; n < 3; ++n) if (c >= dend) goto xperr; else c += *c + 1; if (dns_getdn(pkt, &c, end, dn, DNS_MAXDN) <= 0 || c != dend) goto xperr; c = dptr; printf("%u %u", dns_get16(c+0), dns_get16(c+2)); c += 4; for(n = 0; n < 3; ++n) { putchar(' '); if (verbose > 0) putchar('"'); c = printtxt(c); if (verbose > 0) putchar('"'); } printf(" %s.", dns_dntosp(dn)); break; case DNS_T_KEY: case DNS_T_DNSKEY: /* flags(2) proto(1) algo(1) pubkey */ case DNS_T_DS: case DNS_T_DLV: /* ktag(2) proto(1) algo(1) pubkey */ c = dptr; if (c + 2 + 1 + 1 > dend) goto xperr; printf("%d %d %d", dns_get16(c), c[2], c[3]); c += 2 + 1 + 1; if (c < dend) { putchar(' '); printb64(c, dend); } break; case DNS_T_SIG: case DNS_T_RRSIG: /* type(2) algo(1) labels(1) ottl(4) sexp(4) sinc(4) tag(2) sdn sig */ c = dptr; c += 2 + 1 + 1 + 4 + 4 + 4 + 2; if (dns_getdn(pkt, &c, end, dn, DNS_MAXDN) <= 0) goto xperr; printf("%s %u %u %u ", dns_typename(dns_get16(dptr)), dptr[2], dptr[3], dns_get32(dptr+4)); printdate(dns_get32(dptr+8)); putchar(' '); printdate(dns_get32(dptr+12)); printf(" %d %s. ", dns_get16(dptr+10), dns_dntosp(dn)); printb64(c, dend); break; case DNS_T_SSHFP: /* algo(1), fp type(1), fp... */ if (dend < dptr + 3) goto xperr; printf("%u %u ", dptr[0], dptr[1]); /* algo, fp type */ printhex(dptr + 2, dend); break; #if 0 /* unused RR types? */ case DNS_T_NSEC: /* nextDN bitmaps */ c = dptr; if (dns_getdn(pkt, &c, end, dn, DNS_MAXDN) <= 0) goto xperr; printf("%s.", dns_dntosp(dn)); unfinished. break; #endif case DNS_T_SOA: c = dptr; if (dns_getdn(pkt, &c, end, dn, DNS_MAXDN) <= 0 || dns_getdn(pkt, &c, end, dn, DNS_MAXDN) <= 0 || c + 4*5 != dend) goto xperr; dns_getdn(pkt, &dptr, end, dn, DNS_MAXDN); printf("%s. ", dns_dntosp(dn)); dns_getdn(pkt, &dptr, end, dn, DNS_MAXDN); printf("%s. ", dns_dntosp(dn)); printf("%u %u %u %u %u", dns_get32(dptr), dns_get32(dptr+4), dns_get32(dptr+8), dns_get32(dptr+12), dns_get32(dptr+16)); break; case DNS_T_MINFO: c = dptr; if (dns_getdn(pkt, &c, end, dn, DNS_MAXDN) <= 0 || dns_getdn(pkt, &c, end, dn, DNS_MAXDN) <= 0 || c != dend) goto xperr; dns_getdn(pkt, &dptr, end, dn, DNS_MAXDN); printf("%s. ", dns_dntosp(dn)); dns_getdn(pkt, &dptr, end, dn, DNS_MAXDN); printf("%s.", dns_dntosp(dn)); break; case DNS_T_NULL: default: printhex(dptr, dend); break; } putchar('\n'); return; xperr: printf("\n"); ++errors; } static int printsection(struct dns_parse *p, int nrr, const char *sname) { struct dns_rr rr; int r; if (!nrr) return 0; if (verbose > 1) printf("\n;; %s section (%d):\n", sname, nrr); p->dnsp_rrl = nrr; while((r = dns_nextrr(p, &rr)) > 0) printrr(p, &rr); if (r < 0) printf("<>\n"); return r; } /* dbgcb will only be called if verbose > 1 */ static void dbgcb(int code, const struct sockaddr *sa, unsigned slen, const unsigned char *pkt, int r, const struct dns_query *unused_q, void *unused_data) { struct dns_parse p; const unsigned char *cur, *end; int numqd; (void)unused_q; (void)unused_data; /* avoid compiler warning */ if (code > 0) { printf(";; trying %s.\n", dns_dntosp(dns_payload(pkt))); printf(";; sending %d bytes query to ", r); } else printf(";; received %d bytes response from ", r); if (sa->sa_family == AF_INET && slen >= sizeof(struct sockaddr_in)) printf("%s port %d\n", dns_xntop(AF_INET, &((struct sockaddr_in*)sa)->sin_addr), htons(((struct sockaddr_in*)sa)->sin_port)); #ifdef HAVE_IPv6 else if (sa->sa_family == AF_INET6 && slen >= sizeof(struct sockaddr_in6)) printf("%s port %d\n", dns_xntop(AF_INET6, &((struct sockaddr_in6*)sa)->sin6_addr), htons(((struct sockaddr_in6*)sa)->sin6_port)); #endif else printf("<>\n", sa->sa_family); if (code > 0 && verbose < 3) { putchar('\n'); return; } if (code == -2) printf(";; reply from unexpected source\n"); if (code == -5) printf(";; reply to a query we didn't sent (or old)\n"); if (r < DNS_HSIZE) { printf(";; short packet (%d bytes)\n", r); return; } if (dns_opcode(pkt) != 0) printf(";; unexpected opcode %d\n", dns_opcode(pkt)); if (dns_tc(pkt) != 0) printf(";; warning: TC bit set, probably incomplete reply\n"); printf(";; ->>HEADER<<- opcode: "); switch(dns_opcode(pkt)) { case 0: printf("QUERY"); break; case 1: printf("IQUERY"); break; case 2: printf("STATUS"); break; default: printf("UNKNOWN(%u)", dns_opcode(pkt)); break; } printf(", status: %s, id: %d, size: %d\n;; flags:", dns_rcodename(dns_rcode(pkt)), dns_qid(pkt), r); if (dns_qr(pkt)) printf(" qr"); if (dns_aa(pkt)) printf(" aa"); if (dns_tc(pkt)) printf(" tc"); if (dns_rd(pkt)) printf(" rd"); if (dns_ra(pkt)) printf(" ra"); /* if (dns_z(pkt)) printf(" z"); only one reserved bit left */ if (dns_ad(pkt)) printf(" ad"); if (dns_cd(pkt)) printf(" cd"); numqd = dns_numqd(pkt); printf("; QUERY: %d, ANSWER: %d, AUTHORITY: %d, ADDITIONAL: %d\n", numqd, dns_numan(pkt), dns_numns(pkt), dns_numar(pkt)); if (numqd != 1) printf(";; unexpected number of entries in QUERY section: %d\n", numqd); printf("\n;; QUERY SECTION (%d):\n", numqd); cur = dns_payload(pkt); end = pkt + r; while(numqd--) { if (dns_getdn(pkt, &cur, end, p.dnsp_dnbuf, DNS_MAXDN) <= 0 || cur + 4 > end) { printf("; invalid query section\n"); return; } r = printf(";%s.", dns_dntosp(p.dnsp_dnbuf)); printf("%s%s\t%s\n", r > 23 ? "\t" : r > 15 ? "\t\t" : r > 7 ? "\t\t\t" : "\t\t\t\t", dns_classname(dns_get16(cur+2)), dns_typename(dns_get16(cur))); cur += 4; } p.dnsp_pkt = pkt; p.dnsp_cur = p.dnsp_ans = cur; p.dnsp_end = end; p.dnsp_qdn = NULL; p.dnsp_qcls = 0; p.dnsp_qtyp = 0; p.dnsp_ttl = 0xffffffffu; p.dnsp_nrr = 0; r = printsection(&p, dns_numan(pkt), "ANSWER"); if (r == 0) r = printsection(&p, dns_numns(pkt), "AUTHORITY"); if (r == 0) r = printsection(&p, dns_numar(pkt), "ADDITIONAL"); putchar('\n'); } static void dnscb(struct dns_ctx *ctx, void *result, void *data) { int r = dns_status(ctx); struct query *q = data; struct dns_parse p; struct dns_rr rr; unsigned nrr; unsigned char dn[DNS_MAXDN]; const unsigned char *pkt, *cur, *end; if (!result) { dnserror(q, r); return; } pkt = result; end = pkt + r; cur = dns_payload(pkt); dns_getdn(pkt, &cur, end, dn, sizeof(dn)); dns_initparse(&p, NULL, pkt, cur, end); p.dnsp_qcls = 0; p.dnsp_qtyp = 0; nrr = 0; while((r = dns_nextrr(&p, &rr)) > 0) { if (!dns_dnequal(dn, rr.dnsrr_dn)) continue; if ((qcls == DNS_C_ANY || qcls == rr.dnsrr_cls) && (q->qtyp == DNS_T_ANY || q->qtyp == rr.dnsrr_typ)) ++nrr; else if (rr.dnsrr_typ == DNS_T_CNAME && !nrr) { if (dns_getdn(pkt, &rr.dnsrr_dptr, end, p.dnsp_dnbuf, sizeof(p.dnsp_dnbuf)) <= 0 || rr.dnsrr_dptr != rr.dnsrr_dend) { r = DNS_E_PROTOCOL; break; } else { if (verbose == 1) { printf("%s.", dns_dntosp(dn)); printf(" CNAME %s.\n", dns_dntosp(p.dnsp_dnbuf)); } dns_dntodn(p.dnsp_dnbuf, dn, sizeof(dn)); } } } if (!r && !nrr) r = DNS_E_NODATA; if (r < 0) { dnserror(q, r); free(result); return; } if (verbose < 2) { /* else it is already printed by dbgfn */ dns_rewind(&p, NULL); p.dnsp_qtyp = q->qtyp == DNS_T_ANY ? 0 : q->qtyp; p.dnsp_qcls = qcls == DNS_C_ANY ? 0 : qcls; while(dns_nextrr(&p, &rr)) printrr(&p, &rr); } free(result); query_free(q); } int main(int argc, char **argv) { int i; int fd; fd_set fds; struct timeval tv; time_t now; char *ns[DNS_MAXSERV]; int nns = 0; struct query *q; enum dns_type qtyp = 0; struct dns_ctx *nctx = NULL; int flags = 0; if (!(progname = strrchr(argv[0], '/'))) progname = argv[0]; else argv[0] = ++progname; if (argc <= 1) die(0, "try `%s -h' for help", progname); if (dns_init(NULL, 0) < 0 || !(nctx = dns_new(NULL))) die(errno, "unable to initialize dns library"); /* we keep two dns contexts: one may be needed to resolve * nameservers if given as names, using default options. */ while((i = getopt(argc, argv, "vqt:c:an:o:f:h")) != EOF) switch(i) { case 'v': ++verbose; break; case 'q': --verbose; break; case 't': if (optarg[0] == '*' && !optarg[1]) i = DNS_T_ANY; else if ((i = dns_findtypename(optarg)) <= 0) die(0, "unrecognized query type `%s'", optarg); qtyp = i; break; case 'c': if (optarg[0] == '*' && !optarg[1]) i = DNS_C_ANY; else if ((i = dns_findclassname(optarg)) < 0) die(0, "unrecognized query class `%s'", optarg); qcls = i; break; case 'a': qtyp = DNS_T_ANY; ++verbose; break; case 'n': if (nns >= DNS_MAXSERV) die(0, "too many nameservers, %d max", DNS_MAXSERV); ns[nns++] = optarg; break; case 'o': case 'f': { char *opt; const char *const delim = " \t,;"; for(opt = strtok(optarg, delim); opt != NULL; opt = strtok(NULL, delim)) { if (dns_set_opts(NULL, optarg) == 0) ; else if (strcmp(opt, "aa") == 0) flags |= DNS_AAONLY; else if (strcmp(optarg, "nord") == 0) flags |= DNS_NORD; else if (strcmp(optarg, "dnssec") == 0) flags |= DNS_SET_DO; else if (strcmp(optarg, "do") == 0) flags |= DNS_SET_DO; else if (strcmp(optarg, "cd") == 0) flags |= DNS_SET_CD; else die(0, "invalid option: `%s'", opt); } break; } case 'h': printf( "%s: simple DNS query tool (using udns version %s)\n" "Usage: %s [options] domain-name...\n" "where options are:\n" " -h - print this help and exit\n" " -v - be more verbose\n" " -q - be less verbose\n" " -t type - set query type (A, AAAA, PTR etc)\n" " -c class - set query class (IN (default), CH, HS, *)\n" " -a - equivalent to -t ANY -v\n" " -n ns - use given nameserver(s) instead of default\n" " (may be specified multiple times)\n" " -o opt,opt,... (comma- or space-separated list,\n" " may be specified more than once):\n" " set resovler options (the same as setting $RES_OPTIONS):\n" " timeout:sec - initial query timeout\n" " attempts:num - number of attempt to resovle a query\n" " ndots:num - if name has more than num dots, lookup it before search\n" " port:num - port number for queries instead of default 53\n" " udpbuf:num - size of UDP buffer (use EDNS0 if >512)\n" " or query flags:\n" " aa,nord,dnssec,do,cd - set query flag (auth-only, no recursion,\n" " enable DNSSEC (DNSSEC Ok), check disabled)\n" , progname, dns_version(), progname); return 0; default: die(0, "try `%s -h' for help", progname); } argc -= optind; argv += optind; if (!argc) die(0, "no name(s) to query specified"); if (nns) { /* if nameservers given as names, resolve them. * We only allow IPv4 nameservers as names for now. * Ok, it is easy enouth to try both AAAA and A, * but the question is what to do by default. */ struct sockaddr_in sin; int j, r = 0, opened = 0; memset(&sin, 0, sizeof(sin)); sin.sin_family = AF_INET; sin.sin_port = htons(dns_set_opt(NULL, DNS_OPT_PORT, -1)); dns_add_serv(NULL, NULL); for(i = 0; i < nns; ++i) { if (dns_pton(AF_INET, ns[i], &sin.sin_addr) <= 0) { struct dns_rr_a4 *rr; if (!opened) { if (dns_open(nctx) < 0) die(errno, "unable to initialize dns context"); opened = 1; } rr = dns_resolve_a4(nctx, ns[i], 0); if (!rr) die(0, "unable to resolve nameserver %s: %s", ns[i], dns_strerror(dns_status(nctx))); for(j = 0; j < rr->dnsa4_nrr; ++j) { sin.sin_addr = rr->dnsa4_addr[j]; if ((r = dns_add_serv_s(NULL, (struct sockaddr *)&sin)) < 0) break; } free(rr); } else r = dns_add_serv_s(NULL, (struct sockaddr *)&sin); if (r < 0) die(errno, "unable to add nameserver %s", dns_xntop(AF_INET, &sin.sin_addr)); } } dns_free(nctx); fd = dns_open(NULL); if (fd < 0) die(errno, "unable to initialize dns context"); if (verbose > 1) dns_set_dbgfn(NULL, dbgcb); if (flags) dns_set_opt(NULL, DNS_OPT_FLAGS, flags); for (i = 0; i < argc; ++i) { char *name = argv[i]; union { struct in_addr addr; struct in6_addr addr6; } a; unsigned char dn[DNS_MAXDN]; enum dns_type l_qtyp = 0; int abs; if (dns_pton(AF_INET, name, &a.addr) > 0) { dns_a4todn(&a.addr, 0, dn, sizeof(dn)); l_qtyp = DNS_T_PTR; abs = 1; } #ifdef HAVE_IPv6 else if (dns_pton(AF_INET6, name, &a.addr6) > 0) { dns_a6todn(&a.addr6, 0, dn, sizeof(dn)); l_qtyp = DNS_T_PTR; abs = 1; } #endif else if (!dns_ptodn(name, strlen(name), dn, sizeof(dn), &abs)) die(0, "invalid name `%s'\n", name); else l_qtyp = DNS_T_A; if (qtyp) l_qtyp = qtyp; q = query_new(name, dn, l_qtyp); if (abs) abs = DNS_NOSRCH; if (!dns_submit_dn(NULL, dn, qcls, l_qtyp, abs, 0, dnscb, q)) dnserror(q, dns_status(NULL)); } FD_ZERO(&fds); now = 0; while((i = dns_timeouts(NULL, -1, now)) > 0) { FD_SET(fd, &fds); tv.tv_sec = i; tv.tv_usec = 0; i = select(fd+1, &fds, 0, 0, &tv); now = time(NULL); if (i > 0) dns_ioevent(NULL, now); } return errors ? 1 : notfound ? 100 : 0; } udns-0.6/rblcheck.c0000644000175000017500000002374614571273252012443 0ustar mjtmjt/* rblcheck.c dnsbl (rbl) checker application Copyright (C) 2005 Michael Tokarev This file is part of UDNS library, an async DNS stub resolver. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library, in file named COPYING.LGPL; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #ifdef HAVE_CONFIG_H # include "config.h" #endif #include #include #include #ifdef WINDOWS # include #else # include # include # include # include #endif #include #include #include #include "udns.h" #ifndef HAVE_GETOPT # include "getopt.c" #endif static const char *version = "udns-rblcheck " UDNS_VERSION; static char *progname; static void error(int die, const char *fmt, ...) { va_list ap; fprintf(stderr, "%s: ", progname); va_start(ap, fmt); vfprintf(stderr, fmt, ap); va_end(ap); putc('\n', stderr); fflush(stderr); if (die) exit(1); } struct rblookup { struct ipcheck *parent; struct in_addr key; const char *zone; struct dns_rr_a4 *addr; struct dns_rr_txt *txt; }; struct ipcheck { const char *name; int naddr; int listed; struct rblookup *lookup; }; #define notlisted ((void*)1) static int nzones, nzalloc; static const char **zones; static int do_txt; static int stopfirst; static int verbose = 1; /* verbosity level: * <0 - only bare As/TXTs * 0 - what RBL result * 1(default) - what is listed by RBL: result * 2 - what is[not ]listed by RBL: result, name lookups */ static int listed; static int failures; static void *ecalloc(int size, int cnt) { void *t = calloc(size, cnt); if (!t) error(1, "out of memory"); return t; } static void addzone(const char *zone) { if (nzones >= nzalloc) { const char **zs = (const char**)ecalloc(sizeof(char*), (nzalloc += 16)); if (zones) { memcpy(zs, zones, nzones * sizeof(char*)); free(zones); } zones = zs; } zones[nzones++] = zone; } static int addzonefile(const char *fname) { FILE *f = fopen(fname, "r"); char linebuf[2048]; if (!f) return 0; while(fgets(linebuf, sizeof(linebuf), f)) { char *p = linebuf, *e; while(*p == ' ' || *p == '\t') ++p; if (*p == '#' || *p == '\n') continue; e = p; while(*e && *e != ' ' && *e != '\t' && *e != '\n') ++e; *e++ = '\0'; p = memcpy(ecalloc(e - p, 1), p, e - p); // strdup addzone(p); } fclose(f); return 1; } static void dnserror(struct rblookup *ipl, const char *what) { char buf[4*4]; error(0, "unable to %s for %s (%s): %s", what, dns_ntop(AF_INET, &ipl->key, buf, sizeof(buf)), ipl->zone, dns_strerror(dns_status(0))); ++failures; } static void display_result(struct ipcheck *ipc) { int j; struct rblookup *l, *le; char buf[4*4]; if (!ipc->naddr) return; for (l = ipc->lookup, le = l + nzones * ipc->naddr; l < le; ++l) { if (!l->addr) continue; if (verbose < 2 && l->addr == notlisted) continue; if (verbose >= 0) { dns_ntop(AF_INET, &l->key, buf, sizeof(buf)); if (ipc->name) printf("%s[%s]", ipc->name, buf); else printf("%s", buf); } if (l->addr == notlisted) { printf(" is NOT listed by %s\n", l->zone); continue; } else if (verbose >= 1) printf(" is listed by %s: ", l->zone); else if (verbose >= 0) printf(" %s ", l->zone); if (verbose >= 1 || !do_txt) for (j = 0; j < l->addr->dnsa4_nrr; ++j) printf("%s%s", j ? " " : "", dns_ntop(AF_INET, &l->addr->dnsa4_addr[j], buf, sizeof(buf))); if (!do_txt) ; else if (l->txt) { for(j = 0; j < l->txt->dnstxt_nrr; ++j) { unsigned char *t = l->txt->dnstxt_txt[j].txt; unsigned char *e = t + l->txt->dnstxt_txt[j].len; printf("%s\"", verbose > 0 ? "\n\t" : j ? " " : ""); while(t < e) { if (*t < ' ' || *t >= 127) printf("\\x%02x", *t); else if (*t == '\\' || *t == '"') printf("\\%c", *t); else putchar(*t); ++t; } putchar('"'); } free(l->txt); } else printf("%s", verbose > 0 ? "\n\t" : ""); free(l->addr); putchar('\n'); } free(ipc->lookup); } static void txtcb(struct dns_ctx *ctx, struct dns_rr_txt *r, void *data) { struct rblookup *ipl = data; if (r) { ipl->txt = r; ++ipl->parent->listed; } else if (dns_status(ctx) != DNS_E_NXDOMAIN) dnserror(ipl, "lookup DNSBL TXT record"); } static void a4cb(struct dns_ctx *ctx, struct dns_rr_a4 *r, void *data) { struct rblookup *ipl = data; if (r) { ipl->addr = r; ++listed; if (do_txt) { if (dns_submit_a4dnsbl_txt(0, &ipl->key, ipl->zone, txtcb, ipl)) return; dnserror(ipl, "submit DNSBL TXT record"); } ++ipl->parent->listed; } else if (dns_status(ctx) != DNS_E_NXDOMAIN) dnserror(ipl, "lookup DNSBL A record"); else ipl->addr = notlisted; } static int submit_a_queries(struct ipcheck *ipc, int naddr, const struct in_addr *addr) { int z, a; struct rblookup *rl = ecalloc(sizeof(*rl), nzones * naddr); ipc->lookup = rl; ipc->naddr = naddr; for(a = 0; a < naddr; ++a) { for(z = 0; z < nzones; ++z) { rl->key = addr[a]; rl->zone = zones[z]; rl->parent = ipc; if (!dns_submit_a4dnsbl(0, &rl->key, rl->zone, a4cb, rl)) dnserror(rl, "submit DNSBL A query"); ++rl; } } return 0; } static void namecb(struct dns_ctx *ctx, struct dns_rr_a4 *rr, void *data) { struct ipcheck *ipc = data; if (rr) { submit_a_queries(ipc, rr->dnsa4_nrr, rr->dnsa4_addr); free(rr); } else { error(0, "unable to lookup `%s': %s", ipc->name, dns_strerror(dns_status(ctx))); ++failures; } } static int submit(struct ipcheck *ipc) { struct in_addr addr; if (dns_pton(AF_INET, ipc->name, &addr) > 0) { submit_a_queries(ipc, 1, &addr); ipc->name = NULL; } else if (!dns_submit_a4(0, ipc->name, 0, namecb, ipc)) { error(0, "unable to submit name query for %s: %s\n", ipc->name, dns_strerror(dns_status(0))); ++failures; } return 0; } static void waitdns(struct ipcheck *ipc) { struct timeval tv; fd_set fds; int c; int fd = dns_sock(NULL); time_t now = 0; FD_ZERO(&fds); while((c = dns_timeouts(NULL, -1, now)) > 0) { FD_SET(fd, &fds); tv.tv_sec = c; tv.tv_usec = 0; c = select(fd+1, &fds, NULL, NULL, &tv); now = time(NULL); if (c > 0) dns_ioevent(NULL, now); if (stopfirst && ipc->listed) break; } } int main(int argc, char **argv) { int c; struct ipcheck ipc; char *nameserver = NULL; int zgiven = 0; if (!(progname = strrchr(argv[0], '/'))) progname = argv[0]; else argv[0] = ++progname; while((c = getopt(argc, argv, "hqtvms:S:cn:")) != EOF) switch(c) { case 's': ++zgiven; addzone(optarg); break; case 'S': ++zgiven; if (addzonefile(optarg)) break; error(1, "unable to read zonefile `%s'", optarg); break; /* avoid warning */ case 'c': ++zgiven; nzones = 0; break; case 'q': --verbose; break; case 'v': ++verbose; break; case 't': do_txt = 1; break; case 'n': nameserver = optarg; break; case 'm': ++stopfirst; break; case 'h': printf("%s: %s (udns library version %s).\n", progname, version, dns_version()); printf("Usage is: %s [options] address..\n", progname); printf( "Where options are:\n" " -h - print this help and exit\n" " -s service - add the service (DNSBL zone) to the serice list\n" " -S service-file - add the DNSBL zone(s) read from the given file\n" " -c - clear service list\n" " -v - increase verbosity level (more -vs => more verbose)\n" " -q - decrease verbosity level (opposite of -v)\n" " -t - obtain and print TXT records if any\n" " -m - stop checking after first address match in any list\n" " -n ipaddr - use the given nameserver instead of the default\n" "(if no -s or -S option is given, use $RBLCHECK_ZONES, ~/.rblcheckrc\n" "or /etc/rblcheckrc in that order)\n" ); return 0; default: error(1, "use `%s -h' for help", progname); } if (!zgiven) { char *s = getenv("RBLCHECK_ZONES"); if (s) { char *k; s = strdup(s); for(k = strtok(s, " \t"); k; k = strtok(NULL, " \t")) addzone(k); free(s); } else { /* probably worthless on windows? */ char *path; char *home = getenv("HOME"); if (!home) home = "."; path = malloc(strlen(home) + 1 + sizeof(".rblcheckrc")); sprintf(path, "%s/.rblcheckrc", home); if (!addzonefile(path)) addzonefile("/etc/rblcheckrc"); free(path); } } if (!nzones) error(1, "no service (zone) list specified (-s or -S option)"); argv += optind; argc -= optind; if (!argc) return 0; if (dns_init(NULL, 0) < 0) error(1, "unable to initialize DNS library: %s", strerror(errno)); if (nameserver) { dns_add_serv(NULL, NULL); if (dns_add_serv(NULL, nameserver) < 0) error(1, "wrong IP address for a nameserver: `%s'", nameserver); } if (dns_open(NULL) < 0) error(1, "unable to initialize DNS library: %s", strerror(errno)); for (c = 0; c < argc; ++c) { if (c && (verbose > 1 || (verbose == 1 && do_txt))) putchar('\n'); memset(&ipc, 0, sizeof(ipc)); ipc.name = argv[c]; submit(&ipc); waitdns(&ipc); display_result(&ipc); if (stopfirst > 1 && listed) break; } return listed ? 100 : failures ? 2 : 0; } udns-0.6/ex-rdns.c0000644000175000017500000000620611604616105012226 0ustar mjtmjt/* ex-rdns.c parallel rDNS resolver example - read IP addresses from stdin, write domain names to stdout Copyright (C) 2005 Michael Tokarev This file is part of UDNS library, an async DNS stub resolver. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library, in file named COPYING.LGPL; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include #include #include #include #include #include #include #include #include #include "udns.h" static int curq; static const char *n2ip(const unsigned char *c) { static char b[sizeof("255.255.255.255")]; sprintf(b, "%u.%u.%u.%u", c[0], c[1], c[2], c[3]); return b; } static void dnscb(struct dns_ctx *ctx, struct dns_rr_ptr *rr, void *data) { const char *ip = n2ip((unsigned char *)&data); int i; --curq; if (rr) { printf("%s", ip); for(i = 0; i < rr->dnsptr_nrr; ++i) printf(" %s", rr->dnsptr_ptr[i]); putchar('\n'); free(rr); } else fprintf(stderr, "%s: %s\n", ip, dns_strerror(dns_status(ctx))); } int main(int argc, char **argv) { int c; time_t now; int maxq = 10; struct pollfd pfd; char linebuf[1024]; char *eol; int eof; if (dns_init(NULL, 1) < 0) { fprintf(stderr, "unable to initialize dns library\n"); return 1; } while((c = getopt(argc, argv, "m:r")) != EOF) switch(c) { case 'm': maxq = atoi(optarg); break; case 'r': dns_set_opt(0, DNS_OPT_FLAGS, dns_set_opt(0, DNS_OPT_FLAGS, -1) | DNS_NORD); break; default: return 1; } if (argc != optind) return 1; pfd.fd = dns_sock(0); pfd.events = POLLIN; now = time(NULL); c = optind; eof = 0; while(curq || !eof) { if (!eof && curq < maxq) { union { struct in_addr a; void *p; } pa; if (!fgets(linebuf, sizeof(linebuf), stdin)) { eof = 1; continue; } eol = strchr(linebuf, '\n'); if (eol) *eol = '\0'; if (!linebuf[0]) continue; if (dns_pton(AF_INET, linebuf, &pa.a) <= 0) fprintf(stderr, "%s: invalid address\n", linebuf); else if (dns_submit_a4ptr(0, &pa.a, dnscb, pa.p) == 0) fprintf(stderr, "%s: unable to submit query: %s\n", linebuf, dns_strerror(dns_status(0))); else ++curq; continue; } if (curq) { c = dns_timeouts(0, -1, now); c = poll(&pfd, 1, c < 0 ? -1 : c * 1000); now = time(NULL); if (c) dns_ioevent(0, now); } } return 0; } udns-0.6/NEWS0000644000175000017500000001276614650630520011212 0ustar mjtmjtNEWS User-visible changes in udns library. Recent changes on top. 0.6 (Jul 2024). This is a minor bugfix release. - udns.h: make dst size arg of dns_ntop() unsigned (was int) - bugfix: udns_XtoX.c: it is dns_ntop() & dns_pton(), not udns_* - bugfix: configure: fix inet_ntop() and inet_pton() checks (revealed with gcc-14) - bugfix: dnsget: s/AAA/AAAA/ for the record type in help output - configure.lib: do not run the produced executables (makes cross-building easier) 0.5 (Mar 2024) (yes this is a 10 years gap) - bugfix: wrong init in dns_add_srch() resulting repeating queries twice for non-existing domains. Report and solution from Lennert Buytenhek - bugfix: typo: LDLAGS=>LDFLAGS. Report and solution from Christian Hesse - portability: include before probing for socket() et al, so modern compilers don't fail on -Werror=missing-declarations - remove a few compiler warnings - remove debian/ dir from the release tarball - multiple typo fixes 0.4 (Jan 2014) - bugfix: fix a bug in new list code introduced in 0.3 - portability: use $(LD)/$(LDFLAGS)/$(LIBS) 0.3 (Jan 2014) - bugfix: refactor double-linked list implementation in udns_resolver.c (internal to the library) to be more strict-aliasing-friendly, because old code were miscompiled by gcc. - bugfix: forgotten strdup() in rblcheck 0.2 (Dec 2011) - bugfix: SRV RR handling: fix domain name parsing and crash in case if no port is specified on input for SRV record query - (trivial api) dns_set_opts() now returns number of unrecognized options instead of always returning 0 - dnsget: combine -f and -o options in dnsget (and stop documenting -f), and report unknown/invalid -o options (and error out) - dnsget: pretty-print SSHFP RRs 0.1 (Dec 2010) - bugfix: udns_new(old) - when actually cloning another context - makes the new context referencing memory from old, which leads to crashes when old is modified later - use random queue IDs (the 16bit qID) in queries instead of sequentional ones, based on simple pseudo-random RNG by Bob Jenkins (udns_jran.[ch]). Some people believe that this improves security (CVE-2008-1447). I'm still not convinced (see comments in udns_resolver.c), but it isn't difficult to add after all. - deprecate dns_random16() function which was declared in udns.h (not anymore) but never documented. In order to keep ABI compatible it is still exported. - library has a way now to set query flags (DNS_SET_DO; DNS_SET_CD). - dnsget now prints non-printable chars in all strings in DNS RRs using decimal escape sequences (\%03u) instead of hexadecimal (\%02x) when before - other DNS software does it like this. - recognize a few more record types in dnsget, notable some DNSSEC RRs; add -f option for dnsget to set query flags. - udns is not a Debian native package anymore (was a wrong idea) 0.0.9 (16 Jan 2007) - incompat: minor API changes in dns_init() &friends. dns_init() now requires extra `struct dns_ctx *' argument. Not bumped soversion yet - I only expect one "release" with this change. - many small bugfixes, here and there - more robust FORMERR replies handling - not only such replies are now recognized, but udns retries queries without EDNS0 extensions if tried with, but server reported FORMERR - portability changes, udns now includes getopt() implementation fo the systems lacking it (mostly windows), and dns_ntop()&dns_pton(), which are either just wrappers for system functions or reimplementations. - build is now based on autoconf-like configuration - NAPTR (RFC3403) RR decoding support - new file NOTES which complements TODO somewhat, and includes some important shortcomings - many internal cleanups, including some preparations for better error recovery, security and robustness (and thus API changes) - removed some #defines which are now unused (like DNS_MAXSRCH) - changed WIN32 to WINDOWS everywhere in preprocessor tests, to be able to build it on win64 as well 0.0.8 (12 Sep 2005) - added SRV records (rfc2782) parsing, thanks to Thadeu Lima de Souza Cascardo for implementation. - bugfixes: o use uninitialized value when no reply, library died with assertion: assert((status < 0 && result == 0) || (status >= 0 && result != 0)). o on some OSes, struct sockaddr_in has additional fields, so memcmp'ing two sockaddresses does not work. - rblcheck(.1) 0.0.7 (20 Apr 2005) - dnsget.1 manpage and several enhancements to dnsget. - allow nameserver names for -n option of dnsget. - API change: all dns_submit*() routines now does not expect last `now' argument, since requests aren't sent immediately anymore. - API change: different application timer callback mechanism. Udns now uses single per-context timer instead of per-query. - don't assume DNS replies only contain backward DN pointers, allow forward pointers too. Change parsing API. - debianize 0.0.6 (08 Apr 2005) - use double sorted list for requests (sorted by deadline). This should significantly speed up timeout processing for large number of requests. - changed debugging interface, so it is finally useable (still not documented). - dnsget routine is now Officially Useable, and sometimes even more useable than `host' from BIND distribution (and sometimes not - dnsget does not have -C option and TCP mode) - Debian packaging in debian/ -- udns is now maintained as a native Debian package. - alot (and I really mean alot) of code cleanups all over. udns-0.6/TODO0000644000175000017500000000426711677053552011212 0ustar mjtmjtTODO The following is mostly an internal, not user-visible stuff. * rearrange an API to make dns_query object owned by application, so that it'll look like this: struct dns_query *q; q = dns_query_alloc(ctx); dns_query_set(q, options, domain_name, flags, ...); dns_query_submit(ctx, q); For more information see NOTES file, section "Planned API changes". * allow NULL callbacks? Or provide separate resolver context list of queries which are done but wich did not have callback, and dns_pick() routine to retrieve results from this query, i.e. allow non-callback usage? The non-callback usage may be handy sometimes (any *good* example?), but it will be difficult to provide type-safe non-callback interface due to various RR-specific types in use. * DNS_OPT_FLAGS should be DNS_OPT_ADDFLAGS and DNS_OPT_SETFLAGS. Currently one can't add a single flag bit but preserve existing bits... at least not without retrieving all current flags before, which isn't that bad anyway. * dns_set_opts() may process flags too (such as aaonly etc) * a way to disable $NSCACHEIP et al processing? (with now separate dns_init() and dns_reset(), it has finer control, but still no way to init from system files but ignore environment variables and the like) * initialize/open the context automatically, and be more liberal about initialization in general? * dns_init(ctx, do_open) - make the parameter opposite, aka dns_init(ctx, skip_open) ? * allow TCP queue? * more accurate error reporting. Currently, udns always returns TEMPFAIL, but don't specify why it happened (ENOMEM, timeout, etc). * check the error value returned by recvfrom() and sendto() and determine which errors to ignore. * maybe merge dns_timeouts() and dns_ioevent(), to have only one entry point for everything? For traditional select-loop-based eventloop it may be easier, but for callback-driven event loops the two should be separate. Provide an option, or a single dns_events() entry point for select-loop approach, or just call dns_ioevent() from within dns_timeouts() (probably after renaming it to be dns_events()) ? * implement /etc/hosts lookup too, ala [c-]ares?? * sortlist support? udns-0.6/NOTES0000644000175000017500000002631611566413053011325 0ustar mjtmjtAssorted notes about udns (library). UDP-only mode ~~~~~~~~~~~~~ First of all, since udns is (currently) UDP-only, there are some shortcomings. It assumes that a reply will fit into a UDP buffer. With adoption of EDNS0, and general robustness of IP stacks, in most cases it's not an issue. But in some cases there may be problems: - if an RRset is "very large" so it does not fit even in buffer of size requested by the library (current default is 4096; some servers limits it further), we will not see the reply, or will only see "damaged" reply (depending on the server). - many DNS servers ignores EDNS0 option requests. In this case, no matter which buffer size udns library will request, such servers reply is limited to 512 bytes (standard pre-EDNS0 DNS packet size). (Udns falls back to non-EDNO0 query if EDNS0-enabled one received FORMERR or NOTIMPL error). The problem is that with this, udns currently will not consider replies with TC (truncation) bit set, and will treat such replies the same way as it treats SERVFAIL replies, thus trying next server, or temp-failing the query if no more servers to try. In other words, if the reply is really large, or if the servers you're using don't support EDNS0, your application will be unable to resolve a given name. Yet it's not common situation - in practice, it's very rare. Implementing TCP mode isn't difficult, but it complicates API significantly. Currently udns uses only single UDP socket (or - maybe in the future - two, see below), but in case of TCP, it will need to open and close sockets for TCP connections left and right, and that have to be integrated into an application's event loop in an easy and efficient way. Plus all the timeouts - different for connect(), write, and several stages of read. IPv6 vs IPv4 usage ~~~~~~~~~~~~~~~~~~ This is only relevant for nameservers reachable over IPv6, NOT for IPv6 queries. I.e., if you've IPv6 addresses in 'nameservers' line in your /etc/resolv.conf file. Even more: if you have BOTH IPv6 AND IPv4 addresses there. Or pass them to udns initialization routines. Since udns uses a single UDP socket to communicate with all nameservers, it should support both v4 and v6 communications. Most current platforms supports this mode - using PF_INET6 socket and V4MAPPED addresses, i.e, "tunnelling" IPv4 inside IPv6. But not all systems supports this. And more, it has been said that such mode is deprecated. So, list only IPv4 or only IPv6 addresses, but don't mix them, in your /etc/resolv.conf. An alternative is to use two sockets instead of 1 - one for IPv6 and one for IPv4. For now I'm not sure if it's worth the complexity - again, of the API, not the library itself (but this will not simplify library either). Single socket for all queries ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Using single UDP socket for sending queries to all nameservers has obvious advantages. First it's, again, trivial, simple to use API. And simple library too. Also, after sending queries to all nameservers (in case first didn't reply in time), we will be able to receive late reply from first nameserver and accept it. But this mode has disadvantages too. Most important is that it's much easier to send fake reply to us, as the UDP port where we expects the reply to come to is constant during the whole lifetime of an application. More secure implementations uses random port for every single query. While port number (16 bits integer) can not hold much randomness, it's still of some help. Ok, udns is a stub resolver, so it expects sorta friendly environment, but on LAN it's usually much easier to fire an attack, due to the speed of local network, where a bad guy can generate alot of packets in a short time. Spoofing of replies (Kaminsky attack, CVE-2008-1447) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ While udns uses random numbers for query IDs, it uses single UDP port for all queries (see previous item). And even if it used random UDP port for each query, the attack described in CVE-2008-1447 is still quite trivial. This is not specific to udns library unfortunately - it is inherent property of the protocol. Udns is designed to work in a LAN, it needs full recursive resolver nearby, and modern LAN usually uses high-bandwidth equipment which makes the Kaminsky attack trivial. The problem is that even with qID (16 bits) and random UDP port (about 20 bits available to a regular process) combined still can not hold enough randomness, so on a fast network it is still easy to flood the target with fake replies and hit the "right" reply before real reply comes. So random qIDs don't add much protection anyway, even if this feature is implemented in udns, and using all available techniques wont solve it either. See also long comment in udns_resolver.c, udns_newid(). Assumptions about RRs returned ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Currently udns processes records in the reply it received sequentially. This means that order of the records is significant. For example, if we asked for foo.bar A, but the server returned that foo.bar is a CNAME (alias) for bar.baz, and bar.baz, in turn, has address 1.2.3.4, when the CNAME should come first in reply, followed by A. While DNS specs does not say anything about order of records - it's an rrSET - unordered, - I think an implementation which returns the records in "wrong" order is somewhat insane... CNAME recursion ~~~~~~~~~~~~~~~ Another interesting point is the handling of CNAMEs returned as replies to non-CNAME queries. If we asked for foo.bar A, but it's a CNAME, udns expects BOTH the CNAME itself and the target DN to be present in the reply. In other words, udns DOES NOT RECURSE CNAMES. If we asked for foo.bar A, but only record in reply was that foo.bar is a CNAME for bar.baz, udns will return no records to an application (NXDOMAIN). Strictly speaking, udns should repeat the query asking for bar.baz A, and recurse. But since it's stub resolver, recursive resolver should recurse for us instead. It's not very difficult to implement, however. Probably with some (global?) flag to en/dis-able the feature. Provided there's some demand for it. To clarify: udns handles CNAME recursion in a single reply packet just fine. Note also that standard gethostbyname() routine does not recurse in this situation, too. Error reporting ~~~~~~~~~~~~~~~ Too many places in the code (various failure paths) sets generic "TEMPFAIL" error condition. For example, if no nameserver replied to our query, an application will get generic TEMPFAIL, instead of something like TIMEDOUT. This probably should be fixed, but most applications don't care about the exact reasons of failure - 4 common cases are already too much: - query returned some valid data - NXDOMAIN - valid domain but no data of requested type - =NXDOMAIN in most cases - temporary error - this one sometimes (incorrectly!) treated as NXDOMAIN by (naive) applications. DNS isn't yes/no, it's at least 3 variants, temp err being the 3rd important case! And adding more variations for the temp error case is complicating things even more - again, from an application writer standpoint. For diagnostics, such more specific error cases are of good help. Planned API changes ~~~~~~~~~~~~~~~~~~~ At least one thing I want to change for some future version is a way how queries are submitted and how replies are handled. I want to made dns_query object to be owned by an application. So that instead of udns library allocating it for the lifetime of query, it will be pre- allocated by an application. This simplifies and enhances query submitting interface, and complicates it a bit too, in simplest cases. Currently, we have: dns_submit_dn(dn, cls, typ, flags, parse, cbck, data) dns_submit_p(name, cls, typ, flags, parse, cbck, data) dns_submit_a4(ctx, name, flags, cbck, data) and so on -- with many parameters missed for type-specific cases, but generic cases being too complex for most common usage. Instead, with dns_query being owned by an app, we will be able to separately set up various parts of the query - domain name (various forms), type&class, parser, flags, callback... and even change them at runtime. And we will also be able to reuse query structures, instead of allocating/freeing them every time. So the whole thing will look something like: q = dns_alloc_query(); dns_submit(dns_q_flags(dns_q_a4(q, name, cbck), DNS_F_NOSRCH), data); The idea is to have a set of functions accepting struct dns_query* and returning it (so the calls can be "nested" like the above), to set up relevant parts of the query - specific type of callback, conversion from (type-specific) query parameters into a domain name (this is for type- specific query initializers), and setting various flags and options and type&class things. One example where this is almost essential - if we want to support per-query set of nameservers (which isn't at all useless: imagine a high-volume mail server, were we want to direct DNSBL queries to a separate set of nameservers, and rDNS queries to their own set and so on). Adding another argument (set of nameservers to use) to EVERY query submitting routine is.. insane. Especially since in 99% cases it will be set to default NULL. But with such "nesting" of query initializers, it becomes trivial. This change (the way how queries gets submitted) will NOT break API/ABI compatibility with old versions, since the new submitting API works in parallel with current (and current will use the new one as building blocks, instead of doing all work at once). Another way to do the same is to manipulate query object right after a query has been submitted, but before any events processing (during this time, query object is allocated and initialized, but no actual network packets were sent - it will happen on the next event processing). But this way it become impossible to perform syncronous resolver calls, since those calls hide query objects they use internally. Speaking of replies handling - the planned change is to stop using dynamic memory (malloc) inside the library. That is, instead of allocating a buffer for a reply dynamically in a parsing routine (or memdup'ing the raw reply packet if no parsing routine is specified), I want udns to return the packet buffer it uses internally, and change parsing routines to expect a buffer for result. When parsing, a routine will return true amount of memory it will need to place the result, regardless of whenever it has enough room or not, so that an application can (re)allocate properly sized buffer and call a parsing routine again. This, in theory, also can be done without breaking current API/ABI, but in that case we'll again need a parallel set of routines (parsing included), which makes the library more complicated with too many ways of doing the same thing. Still, code reuse is at good level. Another modification I plan to include is to have an ability to work in terms of domain names (DNs) as used with on-wire DNS packets, not only with asciiz representations of them. For this to work, the above two changes (query submission and result passing) have to be completed first (esp. the query submission part), so that it will be possible to specify some additional query flags (for example) to request domain names instead of the text strings, and to allow easy query submissions with either DNs or text strings. udns-0.6/Makefile.in0000644000175000017500000001335714650630470012561 0ustar mjtmjt#! /usr/bin/make -rf # Makefile.in # libudns Makefile # # Copyright (C) 2005 Michael Tokarev # This file is part of UDNS library, an async DNS stub resolver. # # This library is free software; you can redistribute it and/or # modify it under the terms of the GNU Lesser General Public # License as published by the Free Software Foundation; either # version 2.1 of the License, or (at your option) any later version. # # This library is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU # Lesser General Public License for more details. # # You should have received a copy of the GNU Lesser General Public # License along with this library, in file named COPYING.LGPL; if not, # write to the Free Software Foundation, Inc., 59 Temple Place, # Suite 330, Boston, MA 02111-1307 USA NAME = udns VERS = 0.6 SOVER = 0 SRCS = udns_dn.c udns_dntosp.c udns_parse.c udns_resolver.c udns_init.c \ udns_misc.c udns_XtoX.c \ udns_rr_a.c udns_rr_ptr.c udns_rr_mx.c udns_rr_txt.c udns_bl.c \ udns_rr_srv.c udns_rr_naptr.c udns_codes.c udns_jran.c USRCS = dnsget.c rblcheck.c ex-rdns.c DIST = COPYING.LGPL udns.h udns.3 dnsget.1 rblcheck.1 $(SRCS) $(USRCS) \ NEWS TODO NOTES Makefile.in configure configure.lib \ inet_XtoX.c getopt.c OBJS = $(SRCS:.c=.o) $(GEN:.c=.o) LIB = lib$(NAME).a LIBFL = -L. -l$(NAME) SOBJS = $(OBJS:.o=.lo) SOLIB = lib$(NAME)_s.so SOLIBV = lib$(NAME).so.$(SOVER) SOLIBFL= -L. -l$(NAME)_s UTILS = $(USRCS:.c=) UOBJS = $(USRCS:.c=.o) SOUTILS = $(USRCS:.c=_s) NAMEPFX = $(NAME)-$(VERS) CC = @CC@ CFLAGS = @CFLAGS@ CDEFS = @CDEFS@ LD = @LD@ LDFLAGS = @LDFLAGS@ LIBS = @LIBS@ LDSHARED = $(LD) -shared PICFLAGS = -fPIC AWK = awk TAR = tar all: static .SUFFIXES: .c .o .lo static: $(LIB) $(UTILS) staticlib: $(LIB) $(LIB): $(OBJS) -rm -f $@ $(AR) rv $@ $(OBJS) .c.o: $(CC) $(CFLAGS) $(CDEFS) -c $< shared: $(SOLIBV) $(SOUTILS) sharedlib: $(SOLIBV) $(SOLIBV): $(SOBJS) $(LDSHARED) -Wl,--soname,$(SOLIBV) -o $@ $(SOBJS) $(LDFLAGS) $(LIBS) $(SOLIB): $(SOLIBV) rm -f $@ ln -s $(SOLIBV) $@ .c.lo: $(CC) $(CFLAGS) $(PICFLAGS) $(CDEFS) -o $@ -c $< # udns_codes.c is generated from udns.h udns_codes.c: udns.h @echo Generating $@ @set -e; exec >$@.tmp; \ set T type C class R rcode; \ echo "/* Automatically generated. */"; \ echo "#include \"udns.h\""; \ while [ "$$1" ]; do \ echo; \ echo "const struct dns_nameval dns_$${2}tab[] = {"; \ $(AWK) "/^ DNS_$${1}_[A-Z0-9_]+[ ]*=/ \ { printf \" {%s,\\\"%s\\\"},\\n\", \$$1, substr(\$$1,7) }" \ udns.h ; \ echo " {0,0}};"; \ echo "const char *dns_$${2}name(enum dns_$${2} code) {"; \ echo " static char nm[20];"; \ echo " switch(code) {"; \ $(AWK) "BEGIN{i=0} \ /^ DNS_$${1}_[A-Z0-9_]+[ ]*=/ \ {printf \" case %s: return dns_$${2}tab[%d].name;\\n\",\$$1,i++}\ " udns.h ; \ echo " }"; \ echo " return _dns_format_code(nm,\"$$2\",code);"; \ echo "}"; \ shift 2; \ done @mv $@.tmp $@ udns.3.html: udns.3 groff -man -Thtml udns.3 > $@.tmp mv $@.tmp $@ dist: $(NAMEPFX).tar.gz $(NAMEPFX).tar.gz: $(DIST) $(TAR) -cv -f $@ -z --transform 's|^|$(NAMEPFX)/|' $(DIST) subdist: cp -p $(DIST) $(TARGET)/ clean: rm -f $(OBJS) rm -f $(SOBJS) rm -f $(UOBJS) rm -f config.log distclean: clean rm -f $(LIB) $(SOLIB) $(SOLIBV) udns.3.html rm -f $(UTILS) $(SOUTILS) rm -f config.status config.h Makefile Makefile: configure configure.lib Makefile.in ./configure @echo @echo Please rerun make >&2 @exit 1 .PHONY: all static staticlib shared sharedlib dist clean distclean subdist \ depend dep deps depend dep deps: $(SRCS) $(USRC) @echo Generating deps for: @echo \ $(SRCS) @echo \ $(USRCS) @sed '/^# depend/q' Makefile.in > Makefile.tmp @set -e; \ for f in $(SRCS) $(USRCS); do \ echo $${f%.c}.o $${f%.c}.lo: $$f \ `sed -n 's/^#[ ]*include[ ]*"\(.*\)".*/\1/p' $$f`; \ done >> Makefile.tmp; \ for f in $(USRCS:.c=.o); do \ echo "$${f%.?}: $$f \$$(LIB)"; \ echo " \$$(LD) \$$(LDFLAGS) -o \$$@ $$f \$$(LIBFL) \$$(LIBS)"; \ echo "$${f%.?}_s: $$f \$$(SOLIB)"; \ echo " \$$(LD) \$$(LDFLAGS) -o \$$@ $$f \$$(SOLIBFL)"; \ done >> Makefile.tmp ; \ if cmp Makefile.tmp Makefile.in >/dev/null 2>&1 ; then \ echo Makefile.in unchanged; rm -f Makefile.tmp; \ else \ echo Updating Makfile.in; mv -f Makefile.tmp Makefile.in ; \ fi # depend udns_dn.o udns_dn.lo: udns_dn.c udns.h udns_dntosp.o udns_dntosp.lo: udns_dntosp.c udns.h udns_parse.o udns_parse.lo: udns_parse.c udns.h udns_resolver.o udns_resolver.lo: udns_resolver.c config.h udns.h udns_init.o udns_init.lo: udns_init.c config.h udns.h udns_misc.o udns_misc.lo: udns_misc.c udns.h udns_XtoX.o udns_XtoX.lo: udns_XtoX.c config.h udns.h inet_XtoX.c udns_rr_a.o udns_rr_a.lo: udns_rr_a.c udns.h udns_rr_ptr.o udns_rr_ptr.lo: udns_rr_ptr.c udns.h udns_rr_mx.o udns_rr_mx.lo: udns_rr_mx.c udns.h udns_rr_txt.o udns_rr_txt.lo: udns_rr_txt.c udns.h udns_bl.o udns_bl.lo: udns_bl.c udns.h udns_rr_srv.o udns_rr_srv.lo: udns_rr_srv.c udns.h udns_rr_naptr.o udns_rr_naptr.lo: udns_rr_naptr.c udns.h udns_codes.o udns_codes.lo: udns_codes.c udns.h udns_jran.o udns_jran.lo: udns_jran.c udns.h dnsget.o dnsget.lo: dnsget.c config.h udns.h getopt.c rblcheck.o rblcheck.lo: rblcheck.c config.h udns.h getopt.c ex-rdns.o ex-rdns.lo: ex-rdns.c udns.h dnsget: dnsget.o $(LIB) $(LD) $(LDFLAGS) -o $@ dnsget.o $(LIBFL) $(LIBS) dnsget_s: dnsget.o $(SOLIB) $(LD) $(LDFLAGS) -o $@ dnsget.o $(SOLIBFL) rblcheck: rblcheck.o $(LIB) $(LD) $(LDFLAGS) -o $@ rblcheck.o $(LIBFL) $(LIBS) rblcheck_s: rblcheck.o $(SOLIB) $(LD) $(LDFLAGS) -o $@ rblcheck.o $(SOLIBFL) ex-rdns: ex-rdns.o $(LIB) $(LD) $(LDFLAGS) -o $@ ex-rdns.o $(LIBFL) $(LIBS) ex-rdns_s: ex-rdns.o $(SOLIB) $(LD) $(LDFLAGS) -o $@ ex-rdns.o $(SOLIBFL) udns-0.6/configure0000755000175000017500000000647214650625756012436 0ustar mjtmjt#! /bin/sh # autoconf-style configuration script # set -e name=udns if [ -f udns.h -a -f udns_resolver.c ] ; then : else echo "configure: error: sources not found at `pwd`" >&2 exit 1 fi options="ipv6" for opt in $options; do eval enable_$opt= done if [ -f config.status ]; then . ./config.status fi enable() { opt=`echo "$1" | sed 's/^--[^-]*-//'` case "$opt" in ipv6) ;; *) echo "configure: unrecognized option \`$1'" >&2; exit 1;; esac eval enable_$opt=$2 } while [ $# -gt 0 ]; do case "$1" in --disable-*|--without-*|--no-*) enable "$1" n;; --enable-*|--with-*) enable "$1" y;; --help | --hel | --he | --h | -help | -hel | -he | -h ) cat <&2; exit 1 ;; esac shift done . ./configure.lib ac_msg "configure" ac_result "$name package" ac_prog_c_compiler_v ac_prog_ranlib_v ac_ign ac_yesno "for getopt()" ac_have GETOPT ac_link < extern int optind; extern char *optarg; extern int getopt(int, char **, char *); int main(int argc, char **argv) { getopt(argc, argv, "abc"); return optarg ? optind : 0; } EOF if ac_library_find_v 'socket and connect' "" "-lsocket -lnsl" < #include int main() { socket(0,0,0); connect(0,0,0); return 0; } EOF then : else ac_fatal "cannot find libraries needed for sockets" fi ac_ign \ ac_yesno "for inet_pton() && inet_ntop()" \ ac_have INET_PTON_NTOP \ ac_link < #include #include int main() { char buf[64]; long x = 0; inet_ntop(AF_INET, &x, buf, sizeof(buf)); inet_pton(AF_INET, buf, &x); return x; } EOF if ac_yesno "for socklen_t" ac_compile < #include int foo() { socklen_t len; len = 0; return len; } EOF then : else ac_define socklen_t int fi if [ n != "$enable_ipv6" ]; then if ac_yesno "for IPv6" ac_have IPv6 ac_compile < #include #include int main() { struct sockaddr_in6 sa; sa.sin6_family = AF_INET6; return 0; } EOF then : elif [ "$enable_ipv6" ]; then ac_fatal "IPv6 is requested but not available" fi fi # !disable_ipv6? if ac_yesno "for poll()" ac_have POLL ac_link < #include int main() { struct pollfd pfd[2]; return poll(pfd, 2, 10); } EOF then : else ac_ign ac_yesno "for sys/select.h" ac_have SYS_SELECT_H ac_cpp < #include EOF fi ac_config_h ac_output Makefile ac_msg "creating config.status" rm -f config.status { echo "# automatically generated by configure to hold command-line options" echo found= for opt in $options; do eval val=\$enable_$opt if [ -n "$val" ]; then echo enable_$opt=$val found=y fi done if [ ! "$found" ]; then echo "# (no options encountered)" fi } > config.status ac_result ok ac_result "all done." exit 0 udns-0.6/configure.lib0000644000175000017500000001242114650630470013154 0ustar mjtmjt# configure.lib # a library of shell routines for simple autoconf system # set -e ac_substitutes= rm -f conftest* config.log exec 5>config.log cat <&5 This file contains any messages produced by compilers etc while running configure, to aid debugging if configure script makes a mistake. EOF case `echo "a\c"` in *c*) ac_en=-n ac_ec= ;; *) ac_en= ac_ec='\c' ;; esac ##### Messages ac_msg() { echo $ac_en "$*... $ac_ec" echo ">>> $*" >&5 } ac_checking() { echo $ac_en "checking $*... $ac_ec" echo ">>> checking $*" >&5 } ac_result() { echo "$1" echo "=== $1" >&5 } ac_fatal() { echo "configure: fatal: $*" >&2 echo "=== FATAL: $*" >&5 exit 1 } ac_warning() { echo "configure: warning: $*" >&2 echo "=== WARNING: $*" >&5 } ac_ign() { "$@" || : } # ac_run command... # captures output in conftest.out ac_run() { # apparently UnixWare (for one) /bin/sh optimizes the following "if" # "away", by checking if there's such a command BEFORE redirecting # output. So error message (like "gcc: command not found") goes # to stderr instead of to conftest.out, and `cat conftest.out' below # fails. if "$@" >conftest.out 2>&1; then return 0 else echo "==== Command invocation failed. Command line was:" >&5 echo "$*" >&5 echo "==== compiler input was:" >&5 cat conftest.c >&5 echo "==== output was:" >&5 cat conftest.out >&5 echo "====" >&5 return 1 fi } # common case for ac_verbose: yes/no result ac_yesno() { ac_checking "$1" shift if "$@"; then ac_result yes return 0 else ac_result no return 1 fi } ac_subst() { ac_substitutes="$ac_substitutes $*" } ac_define() { CDEFS="$CDEFS -D$1=${2:-1}" } ac_have() { ac_what=$1; shift if "$@"; then ac_define HAVE_$ac_what eval ac_have_$ac_what=yes return 0 else eval ac_have_$ac_what=no return 1 fi } ##### Compiling, linking # run a compiler ac_run_compiler() { rm -f conftest*; cat >conftest.c ac_run $CC $CFLAGS $CDEFS "$@" conftest.c } ac_compile() { ac_run_compiler -c } ac_link() { ac_run_compiler -o conftest $LIBS "$@" } ac_cpp() { ac_run_compiler -E "$@" } ### check for C compiler. Set $CC, $CFLAGS etc ac_prog_c_compiler_v() { ac_checking "for C compiler" rm -f conftest* echo 'int main(int argc, char **argv) { return 0; }' >conftest.c if [ -n "$CC" ]; then if ac_run $CC -o conftest conftest.c; then ac_result "\$CC ($CC)" else ac_result no ac_fatal "\$CC ($CC) is not a working compiler" fi else for cc in gcc cc ; do if ac_run $cc -o conftest conftest.c; then ac_result "$cc" CC=$cc break fi done if [ -z "$CC" ]; then ac_result no ac_fatal "no working C compiler found in \$PATH. please set \$CC variable" fi fi if [ -z "$CFLAGS" ]; then if ac_yesno "whenever C compiler ($CC) is GNU CC" \ ac_grep_cpp yEs_mAsTeR <conftest.c for lib in "$@"; do if ac_run $CC $CFLAGS $LDFLAGS conftest.c -o conftest $LIBS $lib; then found=y break fi done if [ ! "$found" ]; then ac_result "not found" return 1 fi if [ -z "$lib" ]; then ac_result "ok (none needed)" else ac_result "ok ($lib)" LIBS="$LIBS $lib" fi } ac_compile_run() { ac_link "$@" && ac_run ./conftest } ac_grep_cpp() { pattern="$1"; shift ac_cpp "$@" && grep "$pattern" conftest.out >/dev/null } ac_output() { for var in $ac_substitutes; do eval echo "\"s|@$var@|\$$var|\"" done >conftest.sed for file in "$@"; do ac_msg "creating $file" if [ -f $file.in ]; then sed -f conftest.sed $file.in > $file.tmp mv -f $file.tmp $file ac_result ok else ac_result failed ac_fatal "$file.in not found" fi done rm -f conftest* } ac_config_h() { h=${1:-config.h} ac_msg "creating $h" rm -f $1.tmp echo "/* automatically generated by configure. */" > $h.tmp echo "$CDEFS" | tr ' ' ' ' | sed -e 's/^-D/#define /' -e 's/=/ /' >> $h.tmp if [ -f $h ] && cmp -s $h.tmp $h ; then rm -f $h.tmp ac_result unchanged else mv -f $h.tmp $h ac_result ok fi CDEFS=-DHAVE_CONFIG_H } udns-0.6/inet_XtoX.c0000644000175000017500000001740211604616120012564 0ustar mjtmjt/* inet_XtoX.c * Simple implementation of the following functions: * inet_ntop(), inet_ntoa(), inet_pton(), inet_aton(). * * Differences from traditional implementaitons: * o modifies destination buffers even on error return. * o no fancy (hex, or 1.2) input support in inet_aton() * o inet_aton() does not accept junk after an IP address. * o inet_ntop(AF_INET) requires at least 16 bytes in dest, * and inet_ntop(AF_INET6) at least 40 bytes * (traditional inet_ntop() will try to fit anyway) * * Compile with -Dinet_XtoX_prefix=pfx_ to have pfx_*() instead of inet_*() * Compile with -Dinet_XtoX_no_ntop or -Dinet_XtoX_no_pton * to disable net2str or str2net conversions. * * #define inet_XtoX_prototypes and #include "this_file.c" * to get function prototypes only (but not for inet_ntoa()). * #define inet_XtoX_decl to be `static' for static visibility, * or use __declspec(dllexport) or somesuch... * * Compile with -DTEST to test against stock implementation. * * Written by Michael Tokarev. Public domain. */ #ifdef inet_XtoX_prototypes struct in_addr; #else #include #ifdef TEST # include # include # include # include # include # include # include # undef inet_XtoX_prefix # define inet_XtoX_prefix mjt_inet_ # undef inet_XtoX_no_ntop # undef inet_XtoX_no_pton #else /* !TEST */ struct in_addr { /* declare it here to avoid messing with headers */ unsigned char x[4]; }; #endif /* TEST */ #endif /* inet_XtoX_prototypes */ #ifndef inet_XtoX_prefix # define inet_XtoX_prefix inet_ #endif #ifndef inet_XtoX_decl # define inet_XtoX_decl /*empty*/ #endif #define cc2_(x,y) cc2__(x,y) #define cc2__(x,y) x##y #define fn(x) cc2_(inet_XtoX_prefix,x) #ifndef inet_XtoX_no_ntop inet_XtoX_decl const char * fn(ntop)(int af, const void *src, char *dst, unsigned size); #ifndef inet_XtoX_prototypes static int mjt_ntop4(const void *_src, char *dst, int size) { unsigned i, x, r; char *p; const unsigned char *s = _src; if (size < 4*4) /* for simplicity, disallow non-max-size buffer */ return 0; for (i = 0, p = dst; i < 4; ++i) { if (i) *p++ = '.'; x = r = s[i]; if (x > 99) { *p++ = (char)(r / 100 + '0'); r %= 100; } if (x > 9) { *p++ = (char)(r / 10 + '0'); r %= 10; } *p++ = (char)(r + '0'); } *p = '\0'; return 1; } static char *hexc(char *p, unsigned x) { static char hex[16] = "0123456789abcdef"; if (x > 0x0fff) *p++ = hex[(x >>12) & 15]; if (x > 0x00ff) *p++ = hex[(x >> 8) & 15]; if (x > 0x000f) *p++ = hex[(x >> 4) & 15]; *p++ = hex[x & 15]; return p; } static int mjt_ntop6(const void *_src, char *dst, int size) { unsigned i; unsigned short w[8]; unsigned bs = 0, cs = 0; unsigned bl = 0, cl = 0; char *p; const unsigned char *s = _src; if (size < 40) /* for simplicity, disallow non-max-size buffer */ return 0; for(i = 0; i < 8; ++i, s += 2) { w[i] = (((unsigned short)(s[0])) << 8) | s[1]; if (!w[i]) { if (!cl++) cs = i; } else { if (cl > bl) bl = cl, bs = cs; } } if (cl > bl) bl = cl, bs = cs; p = dst; if (bl == 1) bl = 0; if (bl) { for(i = 0; i < bs; ++i) { if (i) *p++ = ':'; p = hexc(p, w[i]); } *p++ = ':'; i += bl; if (i == 8) *p++ = ':'; } else i = 0; for(; i < 8; ++i) { if (i) *p++ = ':'; if (i == 6 && !bs && (bl == 6 || (bl == 5 && w[5] == 0xffff))) return mjt_ntop4(s - 4, p, size - (p - dst)); p = hexc(p, w[i]); } *p = '\0'; return 1; } inet_XtoX_decl const char * fn(ntop)(int af, const void *src, char *dst, unsigned size) { switch(af) { /* don't use AF_*: don't mess with headers */ case 2: /* AF_INET */ if (mjt_ntop4(src, dst, size)) return dst; break; case 10: /* AF_INET6 */ if (mjt_ntop6(src, dst, size)) return dst; break; default: errno = EAFNOSUPPORT; return (char*)0; } errno = ENOSPC; return (char*)0; } inet_XtoX_decl const char * fn(ntoa)(struct in_addr addr) { static char buf[4*4]; mjt_ntop4(&addr, buf, sizeof(buf)); return buf; } #endif /* inet_XtoX_prototypes */ #endif /* inet_XtoX_no_ntop */ #ifndef inet_XtoX_no_pton inet_XtoX_decl int fn(pton)(int af, const char *src, void *dst); inet_XtoX_decl int fn(aton)(const char *src, struct in_addr *addr); #ifndef inet_XtoX_prototypes static int mjt_pton4(const char *c, void *dst) { unsigned char *a = dst; unsigned n, o; for (n = 0; n < 4; ++n) { if (*c < '0' || *c > '9') return 0; o = *c++ - '0'; while(*c >= '0' && *c <= '9') if ((o = o * 10 + (*c++ - '0')) > 255) return 0; if (*c++ != (n == 3 ? '\0' : '.')) return 0; *a++ = (unsigned char)o; } return 1; } static int mjt_pton6(const char *c, void *dst) { unsigned short w[8], *a = w, *z, *i; unsigned v, o; const char *sc; unsigned char *d = dst; if (*c != ':') z = (unsigned short*)0; else if (*++c != ':') return 0; else ++c, z = a; i = 0; for(;;) { v = 0; sc = c; for(;;) { if (*c >= '0' && *c <= '9') o = *c - '0'; else if (*c >= 'a' && *c <= 'f') o = *c - 'a' + 10; else if (*c >= 'A' && *c <= 'F') o = *c - 'A' + 10; else break; v = (v << 4) | o; if (v > 0xffff) return 0; ++c; } if (sc == c) { if (z == a && !*c) break; else return 0; } if (*c == ':') { if (a >= w + 8) return 0; *a++ = v; if (*++c == ':') { if (z) return 0; z = a; if (!*++c) break; } } else if (!*c) { if (a >= w + 8) return 0; *a++ = v; break; } else if (*c == '.') { if (a > w + 6) return 0; if (!mjt_pton4(sc, d)) return 0; *a++ = ((unsigned)(d[0]) << 8) | d[1]; *a++ = ((unsigned)(d[2]) << 8) | d[3]; break; } else return 0; } v = w + 8 - a; if ((v && !z) || (!v && z)) return 0; for(i = w; ; ++i) { if (i == z) while(v--) { *d++ = '\0'; *d++ = '\0'; } if (i >= a) break; *d++ = (unsigned char)((*i >> 8) & 255); *d++ = (unsigned char)(*i & 255); } return 1; } inet_XtoX_decl int fn(pton)(int af, const char *src, void *dst) { switch(af) { /* don't use AF_*: don't mess with headers */ case 2 /* AF_INET */: return mjt_pton4(src, dst); case 10 /* AF_INET6 */: return mjt_pton6(src, dst); default: errno = EAFNOSUPPORT; return -1; } } inet_XtoX_decl int fn(aton)(const char *src, struct in_addr *addr) { return mjt_pton4(src, addr); } #endif /* inet_XtoX_prototypes */ #endif /* inet_XtoX_no_pton */ #ifdef TEST int main(int argc, char **argv) { int i; char n0[16], n1[16]; char p0[64], p1[64]; int af = AF_INET; int pl = sizeof(p0); int r0, r1; const char *s0, *s1; while((i = getopt(argc, argv, "46a:p:")) != EOF) switch(i) { case '4': af = AF_INET; break; case '6': af = AF_INET6; break; case 'a': case 'p': pl = atoi(optarg); break; default: return 1; } for(i = optind; i < argc; ++i) { char *a = argv[i]; printf("%s:\n", a); r0 = inet_pton(af, a, n0); printf(" p2n stock: %s\n", (r0 < 0 ? "(notsupp)" : !r0 ? "(inval)" : fn(ntop)(af,n0,p0,sizeof(p0)))); r1 = fn(pton)(af, a, n1); printf(" p2n this : %s\n", (r1 < 0 ? "(notsupp)" : !r1 ? "(inval)" : fn(ntop)(af,n1,p1,sizeof(p1)))); if ((r0 > 0) != (r1 > 0) || (r0 > 0 && r1 > 0 && memcmp(n0, n1, af == AF_INET ? 4 : 16) != 0)) printf(" DIFFER!\n"); s0 = inet_ntop(af, n1, p0, pl); printf(" n2p stock: %s\n", s0 ? s0 : "(inval)"); s1 = fn(ntop)(af, n1, p1, pl); printf(" n2p this : %s\n", s1 ? s1 : "(inval)"); if ((s0 != 0) != (s1 != 0) || (s0 && s1 && strcmp(s0, s1) != 0)) printf(" DIFFER!\n"); } return 0; } #endif /* TEST */ udns-0.6/getopt.c0000644000175000017500000000755411604616113012156 0ustar mjtmjt/* getopt.c * Simple getopt() implementation. * * Standard interface: * extern int getopt(int argc, char *const *argv, const char *opts); * extern int optind; current index in argv[] * extern char *optarg; argument for the current option * extern int optopt; the current option * extern int opterr; to control error printing * * Some minor extensions: * ignores leading `+' sign in opts[] (unemplemented GNU extension) * handles optional arguments, in form "x::" in opts[] * if opts[] starts with `:', will return `:' in case of missing required * argument, instead of '?'. * * Compile with -DGETOPT_NO_OPTERR to never print errors internally. * Compile with -DGETOPT_NO_STDIO to use write() calls instead of fprintf() for * error reporting (ignored with -DGETOPT_NO_OPTERR). * Compile with -DGETOPT_CLASS=static to get static linkage. * Compile with -DGETOPT_MY to redefine all visible symbols to be prefixed * with "my_", like my_getopt instead of getopt. * Compile with -DTEST to get a test executable. * * Written by Michael Tokarev. Public domain. */ #include #ifndef GETOPT_CLASS # define GETOPT_CLASS #endif #ifdef GETOPT_MY # define optarg my_optarg # define optind my_optind # define opterr my_opterr # define optopt my_optopt # define getopt my_getopt #endif GETOPT_CLASS char *optarg /* = NULL */; GETOPT_CLASS int optind = 1; GETOPT_CLASS int opterr = 1; GETOPT_CLASS int optopt; static char *nextc /* = NULL */; #if defined(GETOPT_NO_OPTERR) #define printerr(argv, msg) #elif defined(GETOPT_NO_STDIO) extern int write(int, void *, int); static void printerr(char *const *argv, const char *msg) { if (opterr) { char buf[64]; unsigned pl = strlen(argv[0]); unsigned ml = strlen(msg); char *p; if (pl + /*": "*/2 + ml + /*" -- c\n"*/6 > sizeof(buf)) { write(2, argv[0], pl); p = buf; } else { memcpy(buf, argv[0], ml); p = buf + pl; } *p++ = ':'; *p++ = ' '; memcpy(p, msg, ml); p += ml; *p++ = ' '; *p++ = '-'; *p++ = '-'; *p++ = ' '; *p++ = optopt; *p++ = '\n'; write(2, buf, p - buf); } } #else #include static void printerr(char *const *argv, const char *msg) { if (opterr) fprintf(stderr, "%s: %s -- %c\n", argv[0], msg, optopt); } #endif GETOPT_CLASS int getopt(int argc, char *const *argv, const char *opts) { char *p; optarg = 0; if (*opts == '+') /* GNU extension (permutation) - isn't supported */ ++opts; if (!optind) { /* a way to reset things */ nextc = 0; optind = 1; } if (!nextc || !*nextc) { /* advance to the next argv element */ /* done scanning? */ if (optind >= argc) return -1; /* not an optional argument */ if (argv[optind][0] != '-') return -1; /* bare `-' */ if (argv[optind][1] == '\0') return -1; /* special case `--' argument */ if (argv[optind][1] == '-' && argv[optind][2] == '\0') { ++optind; return -1; } nextc = argv[optind] + 1; } optopt = *nextc++; if (!*nextc) ++optind; p = strchr(opts, optopt); if (!p || optopt == ':') { printerr(argv, "illegal option"); return '?'; } if (p[1] == ':') { if (*nextc) { optarg = nextc; nextc = NULL; ++optind; } else if (p[2] != ':') { /* required argument */ if (optind >= argc) { printerr(argv, "option requires an argument"); return *opts == ':' ? ':' : '?'; } else optarg = argv[optind++]; } } return optopt; } #ifdef TEST #include int main(int argc, char **argv) { int c; while((c = getopt(argc, argv, "ab:c::")) != -1) switch(c) { case 'a': case 'b': case 'c': printf("option %c %s\n", c, optarg ? optarg : "(none)"); break; default: return -1; } for(c = optind; c < argc; ++c) printf("non-opt: %s\n", argv[c]); return 0; } #endif