/* $NetBSD: getaddrinfo.c,v 1.54 2001/08/20 02:33:31 itojun Exp $ */ /* $KAME: getaddrinfo.c,v 1.29 2000/08/31 17:26:57 itojun Exp $ */ /* * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the project nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ /* * Issues to be discussed: * - Thread safe-ness must be checked. * - Return values. There are nonstandard return values defined and used * in the source code. This is because RFC2553 is silent about which error * code must be returned for which situation. * - IPv4 classful (shortened) form. RFC2553 is silent about it. XNET 5.2 * says to use inet_aton() to convert IPv4 numeric to binary (alows * classful form as a result). * current code - disallow classful form for IPv4 (due to use of inet_pton). * - freeaddrinfo(NULL). RFC2553 is silent about it. XNET 5.2 says it is * invalid. * current code - SEGV on freeaddrinfo(NULL) * Note: * - We use getipnodebyname() just for thread-safeness. There's no intent * to let it do PF_UNSPEC (actually we never pass PF_UNSPEC to * getipnodebyname(). * - The code filters out AFs that are not supported by the kernel, * when globbing NULL hostname (to loopback, or wildcard). Is it the right * thing to do? What is the relationship with post-RFC2553 AI_ADDRCONFIG * in ai_flags? * - (post-2553) semantics of AI_ADDRCONFIG itself is too vague. * (1) what should we do against numeric hostname (2) what should we do * against NULL hostname (3) what is AI_ADDRCONFIG itself. AF not ready? * non-loopback address configured? global address configured? * - To avoid search order issue, we have a big amount of code duplicate * from gethnamaddr.c and some other places. The issues that there's no * lower layer function to lookup "IPv4 or IPv6" record. Calling * gethostbyname2 from getaddrinfo will end up in wrong search order, as * follows: * - The code makes use of following calls when asked to resolver with * ai_family = PF_UNSPEC: * getipnodebyname(host, AF_INET6); * getipnodebyname(host, AF_INET); * This will result in the following queries if the node is configure to * prefer /etc/hosts than DNS: * lookup /etc/hosts for IPv6 address * lookup DNS for IPv6 address * lookup /etc/hosts for IPv4 address * lookup DNS for IPv4 address * which may not meet people's requirement. * The right thing to happen is to have underlying layer which does * PF_UNSPEC lookup (lookup both) and return chain of addrinfos. * This would result in a bit of code duplicate with _dns_ghbyname() and * friends. */ #include #if defined(LIBC_SCCS) && !defined(lint) __RCSID("$NetBSD: getaddrinfo.c,v 1.54 2001/08/20 02:33:31 itojun Exp $"); #endif /* LIBC_SCCS and not lint */ #include "namespace.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef YP #include #include #include #endif #ifdef __weak_alias __weak_alias(getaddrinfo,_getaddrinfo) __weak_alias(freeaddrinfo,_freeaddrinfo) __weak_alias(gai_strerror,_gai_strerror) #endif #define SUCCESS 0 #define ANY 0 #define YES 1 #define NO 0 static const char in_addrany[] = { 0, 0, 0, 0 }; static const char in_loopback[] = { 127, 0, 0, 1 }; #ifdef INET6 static const char in6_addrany[] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; static const char in6_loopback[] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 }; #endif static const struct afd { int a_af; int a_addrlen; int a_socklen; int a_off; const char *a_addrany; const char *a_loopback; int a_scoped; } afdl [] = { #ifdef INET6 {PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6), offsetof(struct sockaddr_in6, sin6_addr), in6_addrany, in6_loopback, 1}, #endif {PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in), offsetof(struct sockaddr_in, sin_addr), in_addrany, in_loopback, 0}, {0, 0, 0, 0, NULL, NULL, 0}, }; struct explore { int e_af; int e_socktype; int e_protocol; const char *e_protostr; int e_wild; #define WILD_AF(ex) ((ex)->e_wild & 0x01) #define WILD_SOCKTYPE(ex) ((ex)->e_wild & 0x02) #define WILD_PROTOCOL(ex) ((ex)->e_wild & 0x04) }; static const struct explore explore[] = { #if 0 { PF_LOCAL, 0, ANY, ANY, NULL, 0x01 }, #endif #ifdef INET6 { PF_INET6, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 }, { PF_INET6, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 }, { PF_INET6, SOCK_RAW, ANY, NULL, 0x05 }, #endif { PF_INET, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 }, { PF_INET, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 }, { PF_INET, SOCK_RAW, ANY, NULL, 0x05 }, { PF_UNSPEC, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 }, { PF_UNSPEC, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 }, { PF_UNSPEC, SOCK_RAW, ANY, NULL, 0x05 }, { -1, 0, 0, NULL, 0 }, }; #ifdef INET6 #define PTON_MAX 16 #else #define PTON_MAX 4 #endif static const ns_src default_dns_files[] = { { NSSRC_FILES, NS_SUCCESS }, { NSSRC_DNS, NS_SUCCESS }, { 0 } }; #if PACKETSZ > 1024 #define MAXPACKET PACKETSZ #else #define MAXPACKET 1024 #endif typedef union { HEADER hdr; u_char buf[MAXPACKET]; } querybuf; struct res_target { struct res_target *next; const char *name; /* domain name */ int qclass, qtype; /* class and type of query */ u_char *answer; /* buffer to put answer */ int anslen; /* size of answer buffer */ int n; /* result length */ }; static int str_isnumber __P((const char *)); static int explore_fqdn __P((const struct addrinfo *, const char *, const char *, struct addrinfo **)); static int explore_null __P((const struct addrinfo *, const char *, struct addrinfo **)); static int explore_numeric __P((const struct addrinfo *, const char *, const char *, struct addrinfo **)); static int explore_numeric_scope __P((const struct addrinfo *, const char *, const char *, struct addrinfo **)); static int get_canonname __P((const struct addrinfo *, struct addrinfo *, const char *)); static struct addrinfo *get_ai __P((const struct addrinfo *, const struct afd *, const char *)); static int get_portmatch __P((const struct addrinfo *, const char *)); static int get_port __P((struct addrinfo *, const char *, int)); static const struct afd *find_afd __P((int)); #if 0 static int addrconfig __P((const struct addrinfo *)); #endif #ifdef INET6 static int ip6_str2scopeid __P((char *, struct sockaddr_in6 *)); #endif static struct addrinfo *getanswer __P((const querybuf *, int, const char *, int, const struct addrinfo *)); static int _dns_getaddrinfo __P((void *, void *, va_list)); static void _sethtent __P((void)); static void _endhtent __P((void)); static struct addrinfo *_gethtent __P((const char *, const struct addrinfo *)); static int _files_getaddrinfo __P((void *, void *, va_list)); #ifdef YP static struct addrinfo *_yphostent __P((char *, const struct addrinfo *)); static int _yp_getaddrinfo __P((void *, void *, va_list)); #endif static int res_queryN __P((const char *, struct res_target *)); static int res_searchN __P((const char *, struct res_target *)); static int res_querydomainN __P((const char *, const char *, struct res_target *)); static const char * const ai_errlist[] = { "Success", "Address family for hostname not supported", /* EAI_ADDRFAMILY */ "Temporary failure in name resolution", /* EAI_AGAIN */ "Invalid value for ai_flags", /* EAI_BADFLAGS */ "Non-recoverable failure in name resolution", /* EAI_FAIL */ "ai_family not supported", /* EAI_FAMILY */ "Memory allocation failure", /* EAI_MEMORY */ "No address associated with hostname", /* EAI_NODATA */ "hostname nor servname provided, or not known", /* EAI_NONAME */ "servname not supported for ai_socktype", /* EAI_SERVICE */ "ai_socktype not supported", /* EAI_SOCKTYPE */ "System error returned in errno", /* EAI_SYSTEM */ "Invalid value for hints", /* EAI_BADHINTS */ "Resolved protocol is unknown", /* EAI_PROTOCOL */ "Unknown error", /* EAI_MAX */ }; /* XXX macros that make external reference is BAD. */ #define GET_AI(ai, afd, addr) \ do { \ /* external reference: pai, error, and label free */ \ (ai) = get_ai(pai, (afd), (addr)); \ if ((ai) == NULL) { \ error = EAI_MEMORY; \ goto free; \ } \ } while (/*CONSTCOND*/0) #define GET_PORT(ai, serv) \ do { \ /* external reference: error and label free */ \ error = get_port((ai), (serv), 0); \ if (error != 0) \ goto free; \ } while (/*CONSTCOND*/0) #define GET_CANONNAME(ai, str) \ do { \ /* external reference: pai, error and label free */ \ error = get_canonname(pai, (ai), (str)); \ if (error != 0) \ goto free; \ } while (/*CONSTCOND*/0) #define ERR(err) \ do { \ /* external reference: error, and label bad */ \ error = (err); \ goto bad; \ /*NOTREACHED*/ \ } while (/*CONSTCOND*/0) #define MATCH_FAMILY(x, y, w) \ ((x) == (y) || (/*CONSTCOND*/(w) && ((x) == PF_UNSPEC || (y) == PF_UNSPEC))) #define MATCH(x, y, w) \ ((x) == (y) || (/*CONSTCOND*/(w) && ((x) == ANY || (y) == ANY))) char * gai_strerror(ecode) int ecode; { if (ecode < 0 || ecode > EAI_MAX) ecode = EAI_MAX; /* LINTED const castaway */ return (char *) ai_errlist[ecode]; } void freeaddrinfo(ai) struct addrinfo *ai; { struct addrinfo *next; _DIAGASSERT(ai != NULL); do { next = ai->ai_next; if (ai->ai_canonname) free(ai->ai_canonname); /* no need to free(ai->ai_addr) */ free(ai); ai = next; } while (ai); } static int str_isnumber(p) const char *p; { char *ep; _DIAGASSERT(p != NULL); if (*p == '\0') return NO; ep = NULL; (void)strtoul(p, &ep, 10); if (ep && *ep == '\0') return YES; else return NO; } int getaddrinfo(hostname, servname, hints, res) const char *hostname, *servname; const struct addrinfo *hints; struct addrinfo **res; { struct addrinfo sentinel; struct addrinfo *cur; int error = 0; struct addrinfo ai; struct addrinfo ai0; struct addrinfo *pai; const struct explore *ex; /* hostname is allowed to be NULL */ /* servname is allowed to be NULL */ /* hints is allowed to be NULL */ _DIAGASSERT(res != NULL); memset(&sentinel, 0, sizeof(sentinel)); cur = &sentinel; pai = &ai; pai->ai_flags = 0; pai->ai_family = PF_UNSPEC; pai->ai_socktype = ANY; pai->ai_protocol = ANY; pai->ai_addrlen = 0; pai->ai_canonname = NULL; pai->ai_addr = NULL; pai->ai_next = NULL; if (hostname == NULL && servname == NULL) return EAI_NONAME; if (hints) { /* error check for hints */ if (hints->ai_addrlen || hints->ai_canonname || hints->ai_addr || hints->ai_next) ERR(EAI_BADHINTS); /* xxx */ if (hints->ai_flags & ~AI_MASK) ERR(EAI_BADFLAGS); switch (hints->ai_family) { case PF_UNSPEC: case PF_INET: #ifdef INET6 case PF_INET6: #endif break; default: ERR(EAI_FAMILY); } memcpy(pai, hints, sizeof(*pai)); /* * if both socktype/protocol are specified, check if they * are meaningful combination. */ if (pai->ai_socktype != ANY && pai->ai_protocol != ANY) { for (ex = explore; ex->e_af >= 0; ex++) { if (pai->ai_family != ex->e_af) continue; if (ex->e_socktype == ANY) continue; if (ex->e_protocol == ANY) continue; if (pai->ai_socktype == ex->e_socktype && pai->ai_protocol != ex->e_protocol) { ERR(EAI_BADHINTS); } } } } /* * check for special cases. (1) numeric servname is disallowed if * socktype/protocol are left unspecified. (2) servname is disallowed * for raw and other inet{,6} sockets. */ if (MATCH_FAMILY(pai->ai_family, PF_INET, 1) #ifdef PF_INET6 || MATCH_FAMILY(pai->ai_family, PF_INET6, 1) #endif ) { ai0 = *pai; /* backup *pai */ if (pai->ai_family == PF_UNSPEC) { #ifdef PF_INET6 pai->ai_family = PF_INET6; #else pai->ai_family = PF_INET; #endif } error = get_portmatch(pai, servname); if (error) ERR(error); *pai = ai0; } ai0 = *pai; /* NULL hostname, or numeric hostname */ for (ex = explore; ex->e_af >= 0; ex++) { *pai = ai0; /* PF_UNSPEC entries are prepared for DNS queries only */ if (ex->e_af == PF_UNSPEC) continue; if (!MATCH_FAMILY(pai->ai_family, ex->e_af, WILD_AF(ex))) continue; if (!MATCH(pai->ai_socktype, ex->e_socktype, WILD_SOCKTYPE(ex))) continue; if (!MATCH(pai->ai_protocol, ex->e_protocol, WILD_PROTOCOL(ex))) continue; if (pai->ai_family == PF_UNSPEC) pai->ai_family = ex->e_af; if (pai->ai_socktype == ANY && ex->e_socktype != ANY) pai->ai_socktype = ex->e_socktype; if (pai->ai_protocol == ANY && ex->e_protocol != ANY) pai->ai_protocol = ex->e_protocol; if (hostname == NULL) error = explore_null(pai, servname, &cur->ai_next); else error = explore_numeric_scope(pai, hostname, servname, &cur->ai_next); if (error) goto free; while (cur && cur->ai_next) cur = cur->ai_next; } /* * XXX * If numreic representation of AF1 can be interpreted as FQDN * representation of AF2, we need to think again about the code below. */ if (sentinel.ai_next) goto good; if (pai->ai_flags & AI_NUMERICHOST) ERR(EAI_NODATA); if (hostname == NULL) ERR(EAI_NODATA); /* * hostname as alphabetical name. * we would like to prefer AF_INET6 than AF_INET, so we'll make a * outer loop by AFs. */ for (ex = explore; ex->e_af >= 0; ex++) { *pai = ai0; /* require exact match for family field */ if (pai->ai_family != ex->e_af) continue; if (!MATCH(pai->ai_socktype, ex->e_socktype, WILD_SOCKTYPE(ex))) { continue; } if (!MATCH(pai->ai_protocol, ex->e_protocol, WILD_PROTOCOL(ex))) { continue; } if (pai->ai_socktype == ANY && ex->e_socktype != ANY) pai->ai_socktype = ex->e_socktype; if (pai->ai_protocol == ANY && ex->e_protocol != ANY) pai->ai_protocol = ex->e_protocol; error = explore_fqdn(pai, hostname, servname, &cur->ai_next); while (cur && cur->ai_next) cur = cur->ai_next; } /* XXX */ if (sentinel.ai_next) error = 0; if (error) goto free; if (error == 0) { if (sentinel.ai_next) { good: *res = sentinel.ai_next; return SUCCESS; } else error = EAI_FAIL; } free: bad: if (sentinel.ai_next) freeaddrinfo(sentinel.ai_next); *res = NULL; return error; } /* * FQDN hostname, DNS lookup */ static int explore_fqdn(pai, hostname, servname, res) const struct addrinfo *pai; const char *hostname; const char *servname; struct addrinfo **res; { struct addrinfo *result; struct addrinfo *cur; int error = 0; static const ns_dtab dtab[] = { NS_FILES_CB(_files_getaddrinfo, NULL) { NSSRC_DNS, _dns_getaddrinfo, NULL }, /* force -DHESIOD */ NS_NIS_CB(_yp_getaddrinfo, NULL) { 0 } }; _DIAGASSERT(pai != NULL); /* hostname may be NULL */ /* servname may be NULL */ _DIAGASSERT(res != NULL); result = NULL; #if 0 /* * If AI_ADDRCONFIG is specified, check if we are expected to * return the address family or not. * XXX does not handle PF_UNSPEC - should filter out result from * nsdispatch() */ if ((pai->ai_flags & AI_ADDRCONFIG) != 0 && !addrconfig(pai)) return 0; #endif /* * if the servname does not match socktype/protocol, ignore it. */ if (get_portmatch(pai, servname) != 0) return 0; switch (nsdispatch(&result, dtab, NSDB_HOSTS, "getaddrinfo", default_dns_files, hostname, pai)) { case NS_TRYAGAIN: error = EAI_AGAIN; goto free; case NS_UNAVAIL: error = EAI_FAIL; goto free; case NS_NOTFOUND: error = EAI_NODATA; goto free; case NS_SUCCESS: error = 0; for (cur = result; cur; cur = cur->ai_next) { GET_PORT(cur, servname); /* canonname should be filled already */ } break; } *res = result; return 0; free: if (result) freeaddrinfo(result); return error; } /* * hostname == NULL. * passive socket -> anyaddr (0.0.0.0 or ::) * non-passive socket -> localhost (127.0.0.1 or ::1) */ static int explore_null(pai, servname, res) const struct addrinfo *pai; const char *servname; struct addrinfo **res; { int s; const struct afd *afd; struct addrinfo *cur; struct addrinfo sentinel; int error; _DIAGASSERT(pai != NULL); /* servname may be NULL */ _DIAGASSERT(res != NULL); *res = NULL; sentinel.ai_next = NULL; cur = &sentinel; /* * filter out AFs that are not supported by the kernel * XXX errno? */ s = socket(pai->ai_family, SOCK_DGRAM, 0); if (s < 0) { if (errno != EMFILE) return 0; } else close(s); /* * if the servname does not match socktype/protocol, ignore it. */ if (get_portmatch(pai, servname) != 0) return 0; afd = find_afd(pai->ai_family); if (afd == NULL) return 0; if (pai->ai_flags & AI_PASSIVE) { GET_AI(cur->ai_next, afd, afd->a_addrany); /* xxx meaningless? * GET_CANONNAME(cur->ai_next, "anyaddr"); */ GET_PORT(cur->ai_next, servname); } else { GET_AI(cur->ai_next, afd, afd->a_loopback); /* xxx meaningless? * GET_CANONNAME(cur->ai_next, "localhost"); */ GET_PORT(cur->ai_next, servname); } cur = cur->ai_next; *res = sentinel.ai_next; return 0; free: if (sentinel.ai_next) freeaddrinfo(sentinel.ai_next); return error; } /* * numeric hostname */ static int explore_numeric(pai, hostname, servname, res) const struct addrinfo *pai; const char *hostname; const char *servname; struct addrinfo **res; { const struct afd *afd; struct addrinfo *cur; struct addrinfo sentinel; int error; char pton[PTON_MAX]; _DIAGASSERT(pai != NULL); /* hostname may be NULL */ /* servname may be NULL */ _DIAGASSERT(res != NULL); *res = NULL; sentinel.ai_next = NULL; cur = &sentinel; /* * if the servname does not match socktype/protocol, ignore it. */ if (get_portmatch(pai, servname) != 0) return 0; afd = find_afd(pai->ai_family); if (afd == NULL) return 0; switch (afd->a_af) { #if 0 /*X/Open spec*/ case AF_INET: if (inet_aton(hostname, (struct in_addr *)pton) == 1) { if (pai->ai_family == afd->a_af || pai->ai_family == PF_UNSPEC /*?*/) { GET_AI(cur->ai_next, afd, pton); GET_PORT(cur->ai_next, servname); while (cur && cur->ai_next) cur = cur->ai_next; } else ERR(EAI_FAMILY); /*xxx*/ } break; #endif default: if (inet_pton(afd->a_af, hostname, pton) == 1) { if (pai->ai_family == afd->a_af || pai->ai_family == PF_UNSPEC /*?*/) { GET_AI(cur->ai_next, afd, pton); GET_PORT(cur->ai_next, servname); while (cur && cur->ai_next) cur = cur->ai_next; } else ERR(EAI_FAMILY); /*xxx*/ } break; } *res = sentinel.ai_next; return 0; free: bad: if (sentinel.ai_next) freeaddrinfo(sentinel.ai_next); return error; } /* * numeric hostname with scope */ static int explore_numeric_scope(pai, hostname, servname, res) const struct addrinfo *pai; const char *hostname; const char *servname; struct addrinfo **res; { #if !defined(SCOPE_DELIMITER) || !defined(INET6) return explore_numeric(pai, hostname, servname, res); #else const struct afd *afd; struct addrinfo *cur; int error; char *cp, *hostname2 = NULL, *scope, *addr; struct sockaddr_in6 *sin6; _DIAGASSERT(pai != NULL); /* hostname may be NULL */ /* servname may be NULL */ _DIAGASSERT(res != NULL); /* * if the servname does not match socktype/protocol, ignore it. */ if (get_portmatch(pai, servname) != 0) return 0; afd = find_afd(pai->ai_family); if (afd == NULL) return 0; if (!afd->a_scoped) return explore_numeric(pai, hostname, servname, res); cp = strchr(hostname, SCOPE_DELIMITER); if (cp == NULL) return explore_numeric(pai, hostname, servname, res); #if 0 /* * Handle special case of */ hostname2 = strdup(hostname); if (hostname2 == NULL) return EAI_MEMORY; /* terminate at the delimiter */ hostname2[cp - hostname] = '\0'; scope = hostname2; addr = cp + 1; #else /* * Handle special case of */ hostname2 = strdup(hostname); if (hostname2 == NULL) return EAI_MEMORY; /* terminate at the delimiter */ hostname2[cp - hostname] = '\0'; addr = hostname2; scope = cp + 1; #endif error = explore_numeric(pai, addr, servname, res); if (error == 0) { int scopeid; for (cur = *res; cur; cur = cur->ai_next) { if (cur->ai_family != AF_INET6) continue; sin6 = (struct sockaddr_in6 *)(void *)cur->ai_addr; if ((scopeid = ip6_str2scopeid(scope, sin6)) == -1) { free(hostname2); return(EAI_NODATA); /* XXX: is return OK? */ } sin6->sin6_scope_id = scopeid; } } free(hostname2); return error; #endif } static int get_canonname(pai, ai, str) const struct addrinfo *pai; struct addrinfo *ai; const char *str; { _DIAGASSERT(pai != NULL); _DIAGASSERT(ai != NULL); _DIAGASSERT(str != NULL); if ((pai->ai_flags & AI_CANONNAME) != 0) { ai->ai_canonname = (char *)malloc(strlen(str) + 1); if (ai->ai_canonname == NULL) return EAI_MEMORY; strcpy(ai->ai_canonname, str); } return 0; } static struct addrinfo * get_ai(pai, afd, addr) const struct addrinfo *pai; const struct afd *afd; const char *addr; { char *p; struct addrinfo *ai; _DIAGASSERT(pai != NULL); _DIAGASSERT(afd != NULL); _DIAGASSERT(addr != NULL); ai = (struct addrinfo *)malloc(sizeof(struct addrinfo) + (afd->a_socklen)); if (ai == NULL) return NULL; memcpy(ai, pai, sizeof(struct addrinfo)); ai->ai_addr = (struct sockaddr *)(void *)(ai + 1); memset(ai->ai_addr, 0, (size_t)afd->a_socklen); ai->ai_addr->sa_len = afd->a_socklen; ai->ai_addrlen = afd->a_socklen; ai->ai_addr->sa_family = ai->ai_family = afd->a_af; p = (char *)(void *)(ai->ai_addr); memcpy(p + afd->a_off, addr, (size_t)afd->a_addrlen); return ai; } static int get_portmatch(ai, servname) const struct addrinfo *ai; const char *servname; { _DIAGASSERT(ai != NULL); /* servname may be NULL */ /* get_port does not touch first argument. when matchonly == 1. */ /* LINTED const cast */ return get_port((struct addrinfo *)ai, servname, 1); } static int get_port(ai, servname, matchonly) struct addrinfo *ai; const char *servname; int matchonly; { const char *proto; struct servent *sp; int port; int allownumeric; _DIAGASSERT(ai != NULL); /* servname may be NULL */ if (servname == NULL) return 0; switch (ai->ai_family) { case AF_INET: #ifdef AF_INET6 case AF_INET6: #endif break; default: return 0; } switch (ai->ai_socktype) { case SOCK_RAW: return EAI_SERVICE; case SOCK_DGRAM: case SOCK_STREAM: allownumeric = 1; break; case ANY: allownumeric = 0; break; default: return EAI_SOCKTYPE; } if (str_isnumber(servname)) { if (!allownumeric) return EAI_SERVICE; port = htons(atoi(servname)); if (port < 0 || port > 65535) return EAI_SERVICE; } else { switch (ai->ai_socktype) { case SOCK_DGRAM: proto = "udp"; break; case SOCK_STREAM: proto = "tcp"; break; default: proto = NULL; break; } if ((sp = getservbyname(servname, proto)) == NULL) return EAI_SERVICE; port = sp->s_port; } if (!matchonly) { switch (ai->ai_family) { case AF_INET: ((struct sockaddr_in *)(void *) ai->ai_addr)->sin_port = port; break; #ifdef INET6 case AF_INET6: ((struct sockaddr_in6 *)(void *) ai->ai_addr)->sin6_port = port; break; #endif } } return 0; } static const struct afd * find_afd(af) int af; { const struct afd *afd; if (af == PF_UNSPEC) return NULL; for (afd = afdl; afd->a_af; afd++) { if (afd->a_af == af) return afd; } return NULL; } #if 0 /* * post-2553: AI_ADDRCONFIG check. if we use getipnodeby* as backend, backend * will take care of it. * the semantics of AI_ADDRCONFIG is not defined well. we are not sure * if the code is right or not. */ static int addrconfig(pai) const struct addrinfo *pai; { int s; _DIAGASSERT(pai != NULL); /* XXX errno */ s = socket(pai->ai_family, SOCK_DGRAM, 0); if (s < 0) return 0; close(s); return 1; } #endif #ifdef INET6 /* convert a string to a scope identifier. XXX: IPv6 specific */ static int ip6_str2scopeid(scope, sin6) char *scope; struct sockaddr_in6 *sin6; { int scopeid; struct in6_addr *a6; char *ep; _DIAGASSERT(scope != NULL); _DIAGASSERT(sin6 != NULL); a6 = &sin6->sin6_addr; /* empty scopeid portion is invalid */ if (*scope == '\0') return -1; if (IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) { /* * We currently assume a one-to-one mapping between links * and interfaces, so we simply use interface indices for * like-local scopes. */ scopeid = if_nametoindex(scope); if (scopeid == 0) goto trynumeric; return(scopeid); } /* still unclear about literal, allow numeric only - placeholder */ if (IN6_IS_ADDR_SITELOCAL(a6) || IN6_IS_ADDR_MC_SITELOCAL(a6)) goto trynumeric; if (IN6_IS_ADDR_MC_ORGLOCAL(a6)) goto trynumeric; else goto trynumeric; /* global */ /* try to convert to a numeric id as a last resort */ trynumeric: scopeid = (int)strtoul(scope, &ep, 10); if (*ep == '\0') return scopeid; else return -1; } #endif /* code duplicate with gethnamaddr.c */ static const char AskedForGot[] = "gethostby*.getanswer: asked for \"%s\", got \"%s\""; static FILE *hostf = NULL; static struct addrinfo * getanswer(answer, anslen, qname, qtype, pai) const querybuf *answer; int anslen; const char *qname; int qtype; const struct addrinfo *pai; { struct addrinfo sentinel, *cur; struct addrinfo ai; const struct afd *afd; char *canonname; const HEADER *hp; const u_char *cp; int n; const u_char *eom; char *bp; int type, class, buflen, ancount, qdcount; int haveanswer, had_error; char tbuf[MAXDNAME]; int (*name_ok) __P((const char *)); char hostbuf[8*1024]; _DIAGASSERT(answer != NULL); _DIAGASSERT(qname != NULL); _DIAGASSERT(pai != NULL); memset(&sentinel, 0, sizeof(sentinel)); cur = &sentinel; canonname = NULL; eom = answer->buf + anslen; switch (qtype) { case T_A: case T_AAAA: case T_ANY: /*use T_ANY only for T_A/T_AAAA lookup*/ name_ok = res_hnok; break; default: return (NULL); /* XXX should be abort(); */ } /* * find first satisfactory answer */ hp = &answer->hdr; ancount = ntohs(hp->ancount); qdcount = ntohs(hp->qdcount); bp = hostbuf; buflen = sizeof hostbuf; cp = answer->buf + HFIXEDSZ; if (qdcount != 1) { h_errno = NO_RECOVERY; return (NULL); } n = dn_expand(answer->buf, eom, cp, bp, buflen); if ((n < 0) || !(*name_ok)(bp)) { h_errno = NO_RECOVERY; return (NULL); } cp += n + QFIXEDSZ; if (qtype == T_A || qtype == T_AAAA || qtype == T_ANY) { /* res_send() has already verified that the query name is the * same as the one we sent; this just gets the expanded name * (i.e., with the succeeding search-domain tacked on). */ n = strlen(bp) + 1; /* for the \0 */ if (n >= MAXHOSTNAMELEN) { h_errno = NO_RECOVERY; return (NULL); } canonname = bp; bp += n; buflen -= n; /* The qname can be abbreviated, but h_name is now absolute. */ qname = canonname; } haveanswer = 0; had_error = 0; while (ancount-- > 0 && cp < eom && !had_error) { n = dn_expand(answer->buf, eom, cp, bp, buflen); if ((n < 0) || !(*name_ok)(bp)) { had_error++; continue; } cp += n; /* name */ type = _getshort(cp); cp += INT16SZ; /* type */ class = _getshort(cp); cp += INT16SZ + INT32SZ; /* class, TTL */ n = _getshort(cp); cp += INT16SZ; /* len */ if (class != C_IN) { /* XXX - debug? syslog? */ cp += n; continue; /* XXX - had_error++ ? */ } if ((qtype == T_A || qtype == T_AAAA || qtype == T_ANY) && type == T_CNAME) { n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf); if ((n < 0) || !(*name_ok)(tbuf)) { had_error++; continue; } cp += n; /* Get canonical name. */ n = strlen(tbuf) + 1; /* for the \0 */ if (n > buflen || n >= MAXHOSTNAMELEN) { had_error++; continue; } strcpy(bp, tbuf); canonname = bp; bp += n; buflen -= n; continue; } if (qtype == T_ANY) { if (!(type == T_A || type == T_AAAA)) { cp += n; continue; } } else if (type != qtype) { if (type != T_KEY && type != T_SIG) syslog(LOG_NOTICE|LOG_AUTH, "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"", qname, p_class(C_IN), p_type(qtype), p_type(type)); cp += n; continue; /* XXX - had_error++ ? */ } switch (type) { case T_A: case T_AAAA: if (strcasecmp(canonname, bp) != 0) { syslog(LOG_NOTICE|LOG_AUTH, AskedForGot, canonname, bp); cp += n; continue; /* XXX - had_error++ ? */ } if (type == T_A && n != INADDRSZ) { cp += n; continue; } if (type == T_AAAA && n != IN6ADDRSZ) { cp += n; continue; } if (!haveanswer) { int nn; canonname = bp; nn = strlen(bp) + 1; /* for the \0 */ bp += nn; buflen -= nn; } /* don't overwrite pai */ ai = *pai; ai.ai_family = (type == T_A) ? AF_INET : AF_INET6; afd = find_afd(ai.ai_family); if (afd == NULL) { cp += n; continue; } cur->ai_next = get_ai(&ai, afd, (const char *)cp); if (cur->ai_next == NULL) had_error++; while (cur && cur->ai_next) cur = cur->ai_next; cp += n; break; default: abort(); } if (!had_error) haveanswer++; } if (haveanswer) { if (!canonname) (void)get_canonname(pai, sentinel.ai_next, qname); else (void)get_canonname(pai, sentinel.ai_next, canonname); h_errno = NETDB_SUCCESS; return sentinel.ai_next; } h_errno = NO_RECOVERY; return NULL; } /*ARGSUSED*/ static int _dns_getaddrinfo(rv, cb_data, ap) void *rv; void *cb_data; va_list ap; { struct addrinfo *ai; querybuf buf, buf2; const char *name; const struct addrinfo *pai; struct addrinfo sentinel, *cur; struct res_target q, q2; name = va_arg(ap, char *); pai = va_arg(ap, const struct addrinfo *); memset(&q, 0, sizeof(q2)); memset(&q2, 0, sizeof(q2)); memset(&sentinel, 0, sizeof(sentinel)); cur = &sentinel; switch (pai->ai_family) { case AF_UNSPEC: /* prefer IPv6 */ q.name = name; q.qclass = C_IN; q.qtype = T_AAAA; q.answer = buf.buf; q.anslen = sizeof(buf); q.next = &q2; q2.name = name; q2.qclass = C_IN; q2.qtype = T_A; q2.answer = buf2.buf; q2.anslen = sizeof(buf2); break; case AF_INET: q.name = name; q.qclass = C_IN; q.qtype = T_A; q.answer = buf.buf; q.anslen = sizeof(buf); break; case AF_INET6: q.name = name; q.qclass = C_IN; q.qtype = T_AAAA; q.answer = buf.buf; q.anslen = sizeof(buf); break; default: return NS_UNAVAIL; } if (res_searchN(name, &q) < 0) return NS_NOTFOUND; ai = getanswer(&buf, q.n, q.name, q.qtype, pai); if (ai) { cur->ai_next = ai; while (cur && cur->ai_next) cur = cur->ai_next; } if (q.next) { ai = getanswer(&buf2, q2.n, q2.name, q2.qtype, pai); if (ai) cur->ai_next = ai; } if (sentinel.ai_next == NULL) switch (h_errno) { case HOST_NOT_FOUND: return NS_NOTFOUND; case TRY_AGAIN: return NS_TRYAGAIN; default: return NS_UNAVAIL; } *((struct addrinfo **)rv) = sentinel.ai_next; return NS_SUCCESS; } static void _sethtent() { if (!hostf) hostf = fopen(_PATH_HOSTS, "r" ); else rewind(hostf); } static void _endhtent() { if (hostf) { (void) fclose(hostf); hostf = NULL; } } static struct addrinfo * _gethtent(name, pai) const char *name; const struct addrinfo *pai; { char *p; char *cp, *tname, *cname; struct addrinfo hints, *res0, *res; int error; const char *addr; char hostbuf[8*1024]; _DIAGASSERT(name != NULL); _DIAGASSERT(pai != NULL); if (!hostf && !(hostf = fopen(_PATH_HOSTS, "r" ))) return (NULL); again: if (!(p = fgets(hostbuf, sizeof hostbuf, hostf))) return (NULL); if (*p == '#') goto again; if (!(cp = strpbrk(p, "#\n"))) goto again; *cp = '\0'; if (!(cp = strpbrk(p, " \t"))) goto again; *cp++ = '\0'; addr = p; /* if this is not something we're looking for, skip it. */ cname = NULL; while (cp && *cp) { if (*cp == ' ' || *cp == '\t') { cp++; continue; } if (!cname) cname = cp; tname = cp; if ((cp = strpbrk(cp, " \t")) != NULL) *cp++ = '\0'; if (strcasecmp(name, tname) == 0) goto found; } goto again; found: hints = *pai; hints.ai_flags = AI_NUMERICHOST; error = getaddrinfo(addr, NULL, &hints, &res0); if (error) goto again; for (res = res0; res; res = res->ai_next) { /* cover it up */ res->ai_flags = pai->ai_flags; if (pai->ai_flags & AI_CANONNAME) { if (get_canonname(pai, res, cname) != 0) { freeaddrinfo(res0); goto again; } } } return res0; } /*ARGSUSED*/ static int _files_getaddrinfo(rv, cb_data, ap) void *rv; void *cb_data; va_list ap; { const char *name; const struct addrinfo *pai; struct addrinfo sentinel, *cur; struct addrinfo *p; name = va_arg(ap, char *); pai = va_arg(ap, struct addrinfo *); memset(&sentinel, 0, sizeof(sentinel)); cur = &sentinel; _sethtent(); while ((p = _gethtent(name, pai)) != NULL) { cur->ai_next = p; while (cur && cur->ai_next) cur = cur->ai_next; } _endhtent(); *((struct addrinfo **)rv) = sentinel.ai_next; if (sentinel.ai_next == NULL) return NS_NOTFOUND; return NS_SUCCESS; } #ifdef YP static char *__ypdomain; /*ARGSUSED*/ static struct addrinfo * _yphostent(line, pai) char *line; const struct addrinfo *pai; { struct addrinfo sentinel, *cur; struct addrinfo hints, *res, *res0; int error; char *p; const char *addr, *canonname; char *nextline; char *cp; _DIAGASSERT(line != NULL); _DIAGASSERT(pai != NULL); p = line; addr = canonname = NULL; memset(&sentinel, 0, sizeof(sentinel)); cur = &sentinel; nextline: /* terminate line */ cp = strchr(p, '\n'); if (cp) { *cp++ = '\0'; nextline = cp; } else nextline = NULL; cp = strpbrk(p, " \t"); if (cp == NULL) { if (canonname == NULL) return (NULL); else goto done; } *cp++ = '\0'; addr = p; while (cp && *cp) { if (*cp == ' ' || *cp == '\t') { cp++; continue; } if (!canonname) canonname = cp; if ((cp = strpbrk(cp, " \t")) != NULL) *cp++ = '\0'; } hints = *pai; hints.ai_flags = AI_NUMERICHOST; error = getaddrinfo(addr, NULL, &hints, &res0); if (error == 0) { for (res = res0; res; res = res->ai_next) { /* cover it up */ res->ai_flags = pai->ai_flags; if (pai->ai_flags & AI_CANONNAME) (void)get_canonname(pai, res, canonname); } } else res0 = NULL; if (res0) { cur->ai_next = res0; while (cur && cur->ai_next) cur = cur->ai_next; } if (nextline) { p = nextline; goto nextline; } done: return sentinel.ai_next; } /*ARGSUSED*/ static int _yp_getaddrinfo(rv, cb_data, ap) void *rv; void *cb_data; va_list ap; { struct addrinfo sentinel, *cur; struct addrinfo *ai = NULL; static char *__ypcurrent; int __ypcurrentlen, r; const char *name; const struct addrinfo *pai; name = va_arg(ap, char *); pai = va_arg(ap, const struct addrinfo *); memset(&sentinel, 0, sizeof(sentinel)); cur = &sentinel; if (!__ypdomain) { if (_yp_check(&__ypdomain) == 0) return NS_UNAVAIL; } if (__ypcurrent) free(__ypcurrent); __ypcurrent = NULL; /* hosts.byname is only for IPv4 (Solaris8) */ if (pai->ai_family == PF_UNSPEC || pai->ai_family == PF_INET) { r = yp_match(__ypdomain, "hosts.byname", name, (int)strlen(name), &__ypcurrent, &__ypcurrentlen); if (r == 0) { struct addrinfo ai4; ai4 = *pai; ai4.ai_family = AF_INET; ai = _yphostent(__ypcurrent, &ai4); if (ai) { cur->ai_next = ai; while (cur && cur->ai_next) cur = cur->ai_next; } } } /* ipnodes.byname can hold both IPv4/v6 */ r = yp_match(__ypdomain, "ipnodes.byname", name, (int)strlen(name), &__ypcurrent, &__ypcurrentlen); if (r == 0) { ai = _yphostent(__ypcurrent, pai); if (ai) { cur->ai_next = ai; while (cur && cur->ai_next) cur = cur->ai_next; } } if (sentinel.ai_next == NULL) { h_errno = HOST_NOT_FOUND; return NS_NOTFOUND; } *((struct addrinfo **)rv) = sentinel.ai_next; return NS_SUCCESS; } #endif /* resolver logic */ /* * Formulate a normal query, send, and await answer. * Returned answer is placed in supplied buffer "answer". * Perform preliminary check of answer, returning success only * if no error is indicated and the answer count is nonzero. * Return the size of the response on success, -1 on error. * Error number is left in h_errno. * * Caller must parse answer and determine whether it answers the question. */ static int res_queryN(name, target) const char *name; /* domain name */ struct res_target *target; { u_char buf[MAXPACKET]; HEADER *hp; int n; struct res_target *t; int rcode; int ancount; _DIAGASSERT(name != NULL); /* XXX: target may be NULL??? */ rcode = NOERROR; ancount = 0; if ((_res.options & RES_INIT) == 0 && res_init() == -1) { h_errno = NETDB_INTERNAL; return (-1); } for (t = target; t; t = t->next) { int class, type; u_char *answer; int anslen; hp = (HEADER *)(void *)t->answer; hp->rcode = NOERROR; /* default */ /* make it easier... */ class = t->qclass; type = t->qtype; answer = t->answer; anslen = t->anslen; #ifdef DEBUG if (_res.options & RES_DEBUG) printf(";; res_query(%s, %d, %d)\n", name, class, type); #endif n = res_mkquery(QUERY, name, class, type, NULL, 0, NULL, buf, sizeof(buf)); #ifdef RES_USE_EDNS0 if (n > 0 && (_res.options & RES_USE_EDNS0) != 0) n = res_opt(n, buf, sizeof(buf), anslen); #endif if (n <= 0) { #ifdef DEBUG if (_res.options & RES_DEBUG) printf(";; res_query: mkquery failed\n"); #endif h_errno = NO_RECOVERY; return (n); } n = res_send(buf, n, answer, anslen); #if 0 if (n < 0) { #ifdef DEBUG if (_res.options & RES_DEBUG) printf(";; res_query: send error\n"); #endif h_errno = TRY_AGAIN; return (n); } #endif if (n < 0 || hp->rcode != NOERROR || ntohs(hp->ancount) == 0) { rcode = hp->rcode; /* record most recent error */ #ifdef DEBUG if (_res.options & RES_DEBUG) printf(";; rcode = %d, ancount=%d\n", hp->rcode, ntohs(hp->ancount)); #endif continue; } ancount += ntohs(hp->ancount); t->n = n; } if (ancount == 0) { switch (rcode) { case NXDOMAIN: h_errno = HOST_NOT_FOUND; break; case SERVFAIL: h_errno = TRY_AGAIN; break; case NOERROR: h_errno = NO_DATA; break; case FORMERR: case NOTIMP: case REFUSED: default: h_errno = NO_RECOVERY; break; } return (-1); } return (ancount); } /* * Formulate a normal query, send, and retrieve answer in supplied buffer. * Return the size of the response on success, -1 on error. * If enabled, implement search rules until answer or unrecoverable failure * is detected. Error code, if any, is left in h_errno. */ static int res_searchN(name, target) const char *name; /* domain name */ struct res_target *target; { const char *cp, * const *domain; HEADER *hp; u_int dots; int trailing_dot, ret, saved_herrno; int got_nodata = 0, got_servfail = 0, tried_as_is = 0; _DIAGASSERT(name != NULL); _DIAGASSERT(target != NULL); hp = (HEADER *)(void *)target->answer; /*XXX*/ if ((_res.options & RES_INIT) == 0 && res_init() == -1) { h_errno = NETDB_INTERNAL; return (-1); } errno = 0; h_errno = HOST_NOT_FOUND; /* default, if we never query */ dots = 0; for (cp = name; *cp; cp++) dots += (*cp == '.'); trailing_dot = 0; if (cp > name && *--cp == '.') trailing_dot++; /* * if there aren't any dots, it could be a user-level alias */ if (!dots && (cp = __hostalias(name)) != NULL) return (res_queryN(cp, target)); /* * If there are dots in the name already, let's just give it a try * 'as is'. The threshold can be set with the "ndots" option. */ saved_herrno = -1; if (dots >= _res.ndots) { ret = res_querydomainN(name, NULL, target); if (ret > 0) return (ret); saved_herrno = h_errno; tried_as_is++; } /* * We do at least one level of search if * - there is no dot and RES_DEFNAME is set, or * - there is at least one dot, there is no trailing dot, * and RES_DNSRCH is set. */ if ((!dots && (_res.options & RES_DEFNAMES)) || (dots && !trailing_dot && (_res.options & RES_DNSRCH))) { int done = 0; for (domain = (const char * const *)_res.dnsrch; *domain && !done; domain++) { ret = res_querydomainN(name, *domain, target); if (ret > 0) return (ret); /* * If no server present, give up. * If name isn't found in this domain, * keep trying higher domains in the search list * (if that's enabled). * On a NO_DATA error, keep trying, otherwise * a wildcard entry of another type could keep us * from finding this entry higher in the domain. * If we get some other error (negative answer or * server failure), then stop searching up, * but try the input name below in case it's * fully-qualified. */ if (errno == ECONNREFUSED) { h_errno = TRY_AGAIN; return (-1); } switch (h_errno) { case NO_DATA: got_nodata++; /* FALLTHROUGH */ case HOST_NOT_FOUND: /* keep trying */ break; case TRY_AGAIN: if (hp->rcode == SERVFAIL) { /* try next search element, if any */ got_servfail++; break; } /* FALLTHROUGH */ default: /* anything else implies that we're done */ done++; } /* * if we got here for some reason other than DNSRCH, * we only wanted one iteration of the loop, so stop. */ if (!(_res.options & RES_DNSRCH)) done++; } } /* * if we have not already tried the name "as is", do that now. * note that we do this regardless of how many dots were in the * name or whether it ends with a dot. */ if (!tried_as_is) { ret = res_querydomainN(name, NULL, target); if (ret > 0) return (ret); } /* * if we got here, we didn't satisfy the search. * if we did an initial full query, return that query's h_errno * (note that we wouldn't be here if that query had succeeded). * else if we ever got a nodata, send that back as the reason. * else send back meaningless h_errno, that being the one from * the last DNSRCH we did. */ if (saved_herrno != -1) h_errno = saved_herrno; else if (got_nodata) h_errno = NO_DATA; else if (got_servfail) h_errno = TRY_AGAIN; return (-1); } /* * Perform a call on res_query on the concatenation of name and domain, * removing a trailing dot from name if domain is NULL. */ static int res_querydomainN(name, domain, target) const char *name, *domain; struct res_target *target; { char nbuf[MAXDNAME]; const char *longname = nbuf; size_t n, d; _DIAGASSERT(name != NULL); /* XXX: target may be NULL??? */ if ((_res.options & RES_INIT) == 0 && res_init() == -1) { h_errno = NETDB_INTERNAL; return (-1); } #ifdef DEBUG if (_res.options & RES_DEBUG) printf(";; res_querydomain(%s, %s)\n", name, domain?domain:""); #endif if (domain == NULL) { /* * Check for trailing '.'; * copy without '.' if present. */ n = strlen(name); if (n >= MAXDNAME) { h_errno = NO_RECOVERY; return (-1); } if (n > 0 && name[--n] == '.') { strncpy(nbuf, name, n); nbuf[n] = '\0'; } else longname = name; } else { n = strlen(name); d = strlen(domain); if (n + d + 1 >= MAXDNAME) { h_errno = NO_RECOVERY; return (-1); } snprintf(nbuf, sizeof(nbuf), "%s.%s", name, domain); } return (res_queryN(longname, target)); }