/* * Copyright (c) 1985, 1989, 1993 * The Regents of the University of California. 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. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University 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 REGENTS 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 REGENTS 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. */ /* * Portions Copyright (c) 1993 by Digital Equipment Corporation. * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies, and that * the name of Digital Equipment Corporation not be used in advertising or * publicity pertaining to distribution of the document or software without * specific, written prior permission. * * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS * SOFTWARE. */ /* * Portions Copyright (c) 1996-1999 by Internet Software Consortium. * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS * SOFTWARE. */ #if defined(LIBC_SCCS) && !defined(lint) static const char sccsid[] = "@(#)res_send.c 8.1 (Berkeley) 6/4/93"; static const char rcsid[] = "$Id: res_send.c,v 1.1 2006/03/01 19:01:38 majka Exp $"; #endif /* LIBC_SCCS and not lint */ /* * Send query to name server and wait for reply. */ #ifndef __APPLE__ #include "port_before.h" #include "fd_setsize.h" #endif /* * internal_recvfrom uses RFC 2292 API (IPV6_PKTINFO) * __APPLE_USE_RFC_2292 selects the appropriate API in */ #define __APPLE_USE_RFC_2292 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "res_private.h" #ifndef __APPLE__ #include #include "port_after.h" #endif #ifdef __APPLE__ #define ISC_SOCKLEN_T unsigned int #endif /* Options. Leave them on. */ #define DEBUG #define CANNOT_CONNECT_DGRAM #ifdef __APPLE__ #define MULTICAST #endif #include "res_debug.h" #include "res_private.h" #include #define EXT(res) ((res)->_u._ext) static const int highestFD = FD_SETSIZE - 1; #define MAX_HOOK_RETRIES 42 /* port randomization */ #define RANDOM_BIND_MAX_TRIES 16 #define RANDOM_BIND_FIRST IPPORT_HIFIRSTAUTO #define RANDOM_BIND_LAST IPPORT_HILASTAUTO /* Forward. */ static int get_salen __P((const struct sockaddr *)); static int send_vc(res_state, const u_char *, int, u_char *, int *, int *, int, struct sockaddr *, int *, int); static int send_dg(res_state, const u_char *, int, u_char *, int *, int *, int, int *, int *, struct sockaddr *, int *, int); static void Aerror(const res_state, FILE *, const char *, int, const struct sockaddr *, int); static void Perror(const res_state, FILE *, const char *, int); static int sock_eq(struct sockaddr *, struct sockaddr *); #ifdef USE_DNS_PSELECT static int dns_pselect(int, void *, void *, void *, struct timespec *, const sigset_t *); #endif static const int niflags = NI_NUMERICHOST | NI_NUMERICSERV; /* interrupt mechanism is shared with res_query.c */ int interrupt_pipe_enabled = 0; pthread_key_t interrupt_pipe_key; static int bind_random(int sock) { int i, status; uint16_t src_port; struct sockaddr_in local; src_port = 0; status = -1; for (i = 0; (i < RANDOM_BIND_MAX_TRIES) && (status < 0); i++) { /* random port in the range RANDOM_BIND_FIRST to RANDOM_BIND_LAST */ src_port = (res_randomid() % (RANDOM_BIND_LAST - RANDOM_BIND_FIRST)) + RANDOM_BIND_FIRST; memset(&local, 0, sizeof(struct sockaddr_in)); local.sin_port = htons(src_port); status = bind(sock, (struct sockaddr *)&local, sizeof(struct sockaddr_in)); } return status; } void res_delete_interrupt_token(void *token) { int *interrupt_pipe; interrupt_pipe = token; if (interrupt_pipe == NULL) return; if (interrupt_pipe[0] >= 0) { close(interrupt_pipe[0]); interrupt_pipe[0] = -1; } if (interrupt_pipe[1] >= 0) { close(interrupt_pipe[1]); interrupt_pipe[1] = -1; } pthread_setspecific(interrupt_pipe_key, NULL); free(interrupt_pipe); } void * res_init_interrupt_token(void) { int *interrupt_pipe; interrupt_pipe = (int *)malloc(2 * sizeof(int)); if (interrupt_pipe == NULL) return NULL; if (pipe(interrupt_pipe) < 0) { /* this shouldn't happen */ interrupt_pipe[0] = -1; interrupt_pipe[1] = -1; } else { fcntl(interrupt_pipe[0], F_SETFD, FD_CLOEXEC | O_NONBLOCK); fcntl(interrupt_pipe[1], F_SETFD, FD_CLOEXEC | O_NONBLOCK); } pthread_setspecific(interrupt_pipe_key, interrupt_pipe); return interrupt_pipe; } void res_interrupt_requests_enable(void) { interrupt_pipe_enabled = 1; pthread_key_create(&interrupt_pipe_key, NULL); } void res_interrupt_requests_disable(void) { interrupt_pipe_enabled = 0; pthread_key_delete(interrupt_pipe_key); } void res_interrupt_request(void *token) { int oldwrite; int *interrupt_pipe; interrupt_pipe = token; if ((interrupt_pipe == NULL) || (interrupt_pipe_enabled == 0)) return; oldwrite = interrupt_pipe[1]; interrupt_pipe[1] = -1; if (oldwrite >= 0) close(oldwrite); } #ifdef __APPLE__ static struct iovec evConsIovec(void *buf, size_t cnt) { struct iovec ret; memset(&ret, 0xf5, sizeof ret); ret.iov_base = buf; ret.iov_len = cnt; return (ret); } static struct timespec evConsTime(time_t sec, long nsec) { struct timespec x; x.tv_sec = sec; x.tv_nsec = nsec; return (x); } static struct timespec evTimeSpec(struct timeval tv) { struct timespec ts; ts.tv_sec = tv.tv_sec; ts.tv_nsec = tv.tv_usec * 1000; return (ts); } static struct timespec evNowTime() { struct timeval now; if (gettimeofday(&now, NULL) < 0) return (evConsTime(0, 0)); return (evTimeSpec(now)); } #ifdef USE_DNS_PSELECT static struct timeval evTimeVal(struct timespec ts) { struct timeval tv; tv.tv_sec = ts.tv_sec; tv.tv_usec = ts.tv_nsec / 1000; return (tv); } #endif #define BILLION 1000000000 static struct timespec evAddTime(struct timespec addend1, struct timespec addend2) { struct timespec x; x.tv_sec = addend1.tv_sec + addend2.tv_sec; x.tv_nsec = addend1.tv_nsec + addend2.tv_nsec; if (x.tv_nsec >= BILLION) { x.tv_sec++; x.tv_nsec -= BILLION; } return (x); } static struct timespec evSubTime(struct timespec minuend, struct timespec subtrahend) { struct timespec x; x.tv_sec = minuend.tv_sec - subtrahend.tv_sec; if (minuend.tv_nsec >= subtrahend.tv_nsec) { x.tv_nsec = minuend.tv_nsec - subtrahend.tv_nsec; } else { x.tv_nsec = BILLION - subtrahend.tv_nsec + minuend.tv_nsec; x.tv_sec--; } return (x); } static int evCmpTime(struct timespec a, struct timespec b) { long x = a.tv_sec - b.tv_sec; if (x == 0L) x = a.tv_nsec - b.tv_nsec; return (x < 0L ? (-1) : x > 0L ? (1) : (0)); } #endif /* __APPLE__ */ /* Public. */ /* int * res_isourserver(ina) * looks up "ina" in _res.ns_addr_list[] * returns: * 0 : not found * >0 : found * author: * paul vixie, 29may94 */ int res_ourserver_p(const res_state statp, const struct sockaddr *sa) { const struct sockaddr_in *inp, *srv; const struct sockaddr_in6 *in6p, *srv6; int ns; switch (sa->sa_family) { case AF_INET: inp = (const struct sockaddr_in *)sa; for (ns = 0; ns < statp->nscount; ns++) { srv = (struct sockaddr_in *)get_nsaddr(statp, ns); if (srv->sin_family == inp->sin_family && srv->sin_port == inp->sin_port && (srv->sin_addr.s_addr == INADDR_ANY || srv->sin_addr.s_addr == inp->sin_addr.s_addr)) return (1); } break; case AF_INET6: if (EXT(statp).ext == NULL) break; in6p = (const struct sockaddr_in6 *)sa; for (ns = 0; ns < statp->nscount; ns++) { srv6 = (struct sockaddr_in6 *)get_nsaddr(statp, ns); if (srv6->sin6_family == in6p->sin6_family && srv6->sin6_port == in6p->sin6_port && (IN6_IS_ADDR_UNSPECIFIED(&srv6->sin6_addr) || IN6_ARE_ADDR_EQUAL(&srv6->sin6_addr, &in6p->sin6_addr))) return (1); } break; default: break; } return (0); } /* int * res_nameinquery(name, type, class, buf, eom) * look for (name,type,class) in the query section of packet (buf,eom) * requires: * buf + NS_HFIXEDSZ <= eom * returns: * -1 : format error * 0 : not found * >0 : found * author: * paul vixie, 29may94 */ int res_nameinquery(const char *name, int type, int class, const u_char *buf, const u_char *eom) { const u_char *cp = buf + NS_HFIXEDSZ; int qdcount = ntohs(((const HEADER*)buf)->qdcount); while (qdcount-- > 0) { char tname[NS_MAXDNAME+1]; int n, ttype, tclass; n = dn_expand(buf, eom, cp, tname, sizeof tname); if (n < 0) return (-1); cp += n; if (cp + 2 * NS_INT16SZ > eom) return (-1); ttype = ns_get16(cp); cp += NS_INT16SZ; tclass = ns_get16(cp); cp += NS_INT16SZ; if (ttype == type && tclass == class && ns_samename(tname, name) == 1) return (1); } return (0); } /* int * res_queriesmatch(buf1, eom1, buf2, eom2) * is there a 1:1 mapping of (name,type,class) * in (buf1,eom1) and (buf2,eom2)? * returns: * -1 : format error * 0 : not a 1:1 mapping * >0 : is a 1:1 mapping * author: * paul vixie, 29may94 */ int res_queriesmatch(const u_char *buf1, const u_char *eom1, const u_char *buf2, const u_char *eom2) { const u_char *cp = buf1 + NS_HFIXEDSZ; int qdcount = ntohs(((const HEADER*)buf1)->qdcount); if (buf1 + NS_HFIXEDSZ > eom1 || buf2 + NS_HFIXEDSZ > eom2) return (-1); /* * Only header section present in replies to * dynamic update packets. */ if ((((const HEADER *)buf1)->opcode == ns_o_update) && (((const HEADER *)buf2)->opcode == ns_o_update)) return (1); if (qdcount != ntohs(((const HEADER*)buf2)->qdcount)) return (0); while (qdcount-- > 0) { char tname[NS_MAXDNAME+1]; int n, ttype, tclass; n = dn_expand(buf1, eom1, cp, tname, sizeof tname); if (n < 0) return (-1); cp += n; if (cp + 2 * NS_INT16SZ > eom1) return (-1); ttype = ns_get16(cp); cp += NS_INT16SZ; tclass = ns_get16(cp); cp += NS_INT16SZ; if (!res_nameinquery(tname, ttype, tclass, buf2, eom2)) return (0); } return (1); } int dns_res_send(res_state statp, const u_char *buf, int buflen, u_char *ans, int *anssiz, struct sockaddr *from, int *fromlen) { int gotsomewhere, terrno, try, v_circuit, resplen, ns; char abuf[NI_MAXHOST]; char *notify_name; int notify_token, status, send_status, reply_buf_size; uint64_t exit_requested; if (statp->nscount == 0) { errno = ESRCH; return DNS_RES_STATUS_INVALID_RES_STATE; } reply_buf_size = *anssiz; if (reply_buf_size < NS_HFIXEDSZ) { errno = EINVAL; return DNS_RES_STATUS_INVALID_ARGUMENT; } DprintQ((statp->options & RES_DEBUG) || (statp->pfcode & RES_PRF_QUERY), (stdout, ";; res_send()\n"), buf, buflen); v_circuit = (statp->options & RES_USEVC) || (buflen > NS_PACKETSZ); gotsomewhere = 0; send_status = 0; terrno = ETIMEDOUT; /* * If the ns_addr_list in the resolver context has changed, then * invalidate our cached copy and the associated timing data. */ if (EXT(statp).nscount != 0) { int needclose = 0; struct sockaddr_storage peer; ISC_SOCKLEN_T peerlen; if (EXT(statp).nscount != statp->nscount) { needclose++; } else { for (ns = 0; ns < statp->nscount; ns++) { if ((statp->nsaddr_list[ns].sin_family) && (EXT(statp).ext != NULL) && (!sock_eq((struct sockaddr *)&statp->nsaddr_list[ns], (struct sockaddr *)&EXT(statp).ext->nsaddrs[ns]))) { needclose++; break; } if (EXT(statp).nssocks[ns] == -1) continue; peerlen = sizeof(peer); if (getsockname(EXT(statp).nssocks[ns], (struct sockaddr *)&peer, &peerlen) < 0) { needclose++; break; } if (!sock_eq((struct sockaddr *)&peer, get_nsaddr(statp, ns))) { needclose++; break; } } } if (needclose) { res_nclose(statp); EXT(statp).nscount = 0; } } /* * Maybe initialize our private copy of the ns_addr_list. */ if (EXT(statp).nscount == 0) { for (ns = 0; ns < statp->nscount; ns++) { EXT(statp).nstimes[ns] = RES_MAXTIME; EXT(statp).nssocks[ns] = -1; if (!statp->nsaddr_list[ns].sin_family) continue; if (EXT(statp).ext != NULL) EXT(statp).ext->nsaddrs[ns].sin = statp->nsaddr_list[ns]; } EXT(statp).nscount = statp->nscount; } /* * Some resolvers want to even out the load on their nameservers. * Note that RES_BLAST overrides RES_ROTATE. */ if (((statp->options & RES_ROTATE) != 0) && ((statp->options & RES_BLAST) == 0)) { union res_sockaddr_union inu; struct sockaddr_in ina; int lastns = statp->nscount - 1; int fd; u_int16_t nstime; if (EXT(statp).ext != NULL) inu = EXT(statp).ext->nsaddrs[0]; ina = statp->nsaddr_list[0]; fd = EXT(statp).nssocks[0]; nstime = EXT(statp).nstimes[0]; for (ns = 0; ns < lastns; ns++) { if (EXT(statp).ext != NULL) { EXT(statp).ext->nsaddrs[ns] =EXT(statp).ext->nsaddrs[ns + 1]; } statp->nsaddr_list[ns] = statp->nsaddr_list[ns + 1]; EXT(statp).nssocks[ns] = EXT(statp).nssocks[ns + 1]; EXT(statp).nstimes[ns] = EXT(statp).nstimes[ns + 1]; } if (EXT(statp).ext != NULL) EXT(statp).ext->nsaddrs[lastns] = inu; statp->nsaddr_list[lastns] = ina; EXT(statp).nssocks[lastns] = fd; EXT(statp).nstimes[lastns] = nstime; } /* * Get notification token * we use a self-notification token to allow a caller * to signal the thread doing this DNS query to quit. */ notify_name = NULL; notify_token = -1; asprintf(¬ify_name, "self.thread.%lu", (unsigned long)pthread_self()); if (notify_name != NULL) { status = notify_register_plain(notify_name, ¬ify_token); free(notify_name); } /* * Send request, RETRY times, or until successful. */ for (try = 0; try < statp->retry; try++) { for (ns = 0; ns < statp->nscount; ns++) { struct sockaddr *nsap; int nsaplen; nsap = get_nsaddr(statp, ns); nsaplen = get_salen(nsap); send_same_ns: if (statp->qhook) { int done = 0, loops = 0; do { res_sendhookact act; act = (*statp->qhook)(&nsap, &buf, &buflen, ans, reply_buf_size, &resplen); switch (act) { case res_goahead: done = 1; break; case res_nextns: res_nclose(statp); goto send_next_ns; case res_done: if (notify_token != -1) notify_cancel(notify_token); return DNS_RES_STATUS_CANCELLED; case res_modified: /* give the hook another try */ if (++loops < MAX_HOOK_RETRIES) break; /*FALLTHROUGH*/ case res_error: /*FALLTHROUGH*/ default: if (notify_token != -1) notify_cancel(notify_token); return DNS_RES_STATUS_CANCELLED; } } while (!done); } if (notify_token != -1) { exit_requested = 0; status = notify_get_state(notify_token, &exit_requested); if (exit_requested == ThreadStateExitRequested) { Dprint(statp->options & RES_DEBUG, (stdout, ";; cancelled\n")); res_nclose(statp); notify_cancel(notify_token); return DNS_RES_STATUS_CANCELLED; } } Dprint(((statp->options & RES_DEBUG) && getnameinfo(nsap, nsaplen, abuf, sizeof(abuf), NULL, 0, niflags) == 0), (stdout, ";; Querying server (# %d) address = %s\n", ns + 1, abuf)); send_status = ns_r_noerror; if (v_circuit != 0) { /* Use VC; at most one attempt per server. */ try = statp->retry; *anssiz = reply_buf_size; send_status = send_vc(statp, buf, buflen, ans, anssiz, &terrno, ns, from, fromlen, notify_token); } else { /* Use datagrams. */ send_status = send_dg(statp, buf, buflen, ans, anssiz, &terrno, ns, &v_circuit, &gotsomewhere, from, fromlen, notify_token); if (v_circuit != 0) goto send_same_ns; } if ((send_status == DNS_RES_STATUS_SYSTEM_ERROR) || (send_status == DNS_RES_STATUS_CANCELLED)) { res_nclose(statp); if (notify_token != -1) notify_cancel(notify_token); return send_status; } if (send_status != ns_r_noerror) goto send_next_ns; Dprint((statp->options & RES_DEBUG) || ((statp->pfcode & RES_PRF_REPLY) && (statp->pfcode & RES_PRF_HEAD1)), (stdout, ";; got answer:\n")); DprintQ((statp->options & RES_DEBUG) || (statp->pfcode & RES_PRF_REPLY), (stdout, "%s", ""), ans, (*anssiz > reply_buf_size) ? reply_buf_size : *anssiz); /* * If we have temporarily opened a virtual circuit, * or if we haven't been asked to keep a socket open, * close the socket. */ if (((v_circuit != 0) && (statp->options & RES_USEVC) == 0) || (statp->options & RES_STAYOPEN) == 0) res_nclose(statp); if (statp->rhook) { int done = 0, loops = 0; do { res_sendhookact act; act = (*statp->rhook)(nsap, buf, buflen, ans, *anssiz, &resplen); switch (act) { case res_goahead: case res_done: done = 1; break; case res_nextns: res_nclose(statp); goto send_next_ns; case res_modified: /* give the hook another try */ if (++loops < MAX_HOOK_RETRIES) break; /*FALLTHROUGH*/ case res_error: /*FALLTHROUGH*/ default: res_nclose(statp); if (notify_token != -1) notify_cancel(notify_token); return DNS_RES_STATUS_CANCELLED; } } while (!done); } if (notify_token != -1) notify_cancel(notify_token); return ns_r_noerror; send_next_ns: ; } /* foreach ns */ } /* foreach retry */ res_nclose(statp); if (notify_token != -1) notify_cancel(notify_token); if (v_circuit == 0) { /* used datagrams */ if (gotsomewhere != 0) { errno = ECONNREFUSED; return DNS_RES_STATUS_CONNECTION_REFUSED; } errno = ETIMEDOUT; return DNS_RES_STATUS_TIMEOUT; } /* used v_circuit */ errno = terrno; return send_status; } int res_nsend_2(res_state statp, const u_char *buf, int buflen, u_char *ans, int anssiz, struct sockaddr *from, int *fromlen) { int len, status; len = anssiz; status = dns_res_send(statp, buf, buflen, ans, &len, from, fromlen); if (status != ns_r_noerror) len = -1; return len; } int res_nsend(res_state statp, const u_char *buf, int buflen, u_char *ans, int anssiz) { struct sockaddr_storage from; int fromlen; fromlen = sizeof(struct sockaddr_storage); return res_nsend_2(statp, buf, buflen, ans, anssiz, (struct sockaddr *)&from, &fromlen); } /* Private */ static int get_salen(const struct sockaddr *sa) { #ifdef HAVE_SA_LEN /* There are people do not set sa_len. Be forgiving to them. */ if (sa->sa_len) return (sa->sa_len); #endif if (sa->sa_family == AF_INET) return (sizeof(struct sockaddr_in)); else if (sa->sa_family == AF_INET6) return (sizeof(struct sockaddr_in6)); else return (0); /* unknown, die on connect */ } /* * pick appropriate nsaddr_list for use. see res_init() for initialization. */ struct sockaddr * get_nsaddr(res_state statp, size_t n) { if ((!statp->nsaddr_list[n].sin_family) && (EXT(statp).ext != NULL)) { /* * - EXT(statp).ext->nsaddrs[n] holds an address that is larger * than struct sockaddr, and * - user code did not update statp->nsaddr_list[n]. */ return (struct sockaddr *)(void *)&EXT(statp).ext->nsaddrs[n]; } else { /* * - user code updated statp->nsaddr_list[n], or * - statp->nsaddr_list[n] has the same content as * EXT(statp).ext->nsaddrs[n]. */ return (struct sockaddr *)(void *)&statp->nsaddr_list[n]; } } static int send_vc(res_state statp, const u_char *buf, int buflen, u_char *ans, int *anssiz, int *terrno, int ns, struct sockaddr *from, int *fromlen, int notify_token) { const HEADER *hp = (const HEADER *) buf; HEADER *anhp = (HEADER *) ans; struct sockaddr *nsap; int nsaplen; int truncating, connreset, resplen, n; struct iovec iov[2]; u_short len; u_char *cp; void *tmp; int status; uint64_t exit_requested; nsap = get_nsaddr(statp, ns); nsaplen = get_salen(nsap); connreset = 0; vc_same_ns: if (notify_token != -1) { exit_requested = 0; status = notify_get_state(notify_token, &exit_requested); if (exit_requested == ThreadStateExitRequested) { Dprint(statp->options & RES_DEBUG, (stdout, ";; cancelled\n")); *terrno = EINTR; return DNS_RES_STATUS_CANCELLED; } } truncating = 0; /* Are we still talking to whom we want to talk? */ if (statp->_vcsock >= 0 && (statp->_flags & RES_F_VC) != 0) { struct sockaddr_storage peer; ISC_SOCKLEN_T size = sizeof peer; if (getpeername(statp->_vcsock, (struct sockaddr *)&peer, &size) < 0 || !sock_eq((struct sockaddr *)&peer, nsap)) { res_nclose(statp); statp->_flags &= ~RES_F_VC; } } if ((statp->_vcsock < 0) || ((statp->_flags & RES_F_VC) == 0)) { if (statp->_vcsock >= 0) res_nclose(statp); statp->_vcsock = socket(nsap->sa_family, SOCK_STREAM, 0); if (statp->_vcsock > highestFD) { res_nclose(statp); errno = ENOTSOCK; } if (statp->_vcsock < 0) { *terrno = errno; Perror(statp, stderr, "socket(vc)", errno); return DNS_RES_STATUS_SYSTEM_ERROR; } errno = 0; if (connect(statp->_vcsock, nsap, nsaplen) < 0) { *terrno = errno; Aerror(statp, stderr, "connect(vc)", errno, nsap, nsaplen); res_nclose(statp); return DNS_RES_STATUS_CONNECTION_REFUSED; } statp->_flags |= RES_F_VC; } /* * Send length & message */ putshort((u_short)buflen, (u_char*)&len); iov[0] = evConsIovec(&len, NS_INT16SZ); #ifdef __APPLE__ tmp = (char *)buf; #else DE_CONST(buf, tmp); #endif iov[1] = evConsIovec(tmp, buflen); if (writev(statp->_vcsock, iov, 2) != (NS_INT16SZ + buflen)) { *terrno = errno; Perror(statp, stderr, "write failed", errno); res_nclose(statp); return DNS_RES_STATUS_CONNECTION_FAILED; } /* * Receive length & response */ read_len: if (notify_token != -1) { exit_requested = 0; status = notify_get_state(notify_token, &exit_requested); if (exit_requested == ThreadStateExitRequested) { Dprint(statp->options & RES_DEBUG, (stdout, ";; cancelled\n")); *terrno = EINTR; return DNS_RES_STATUS_CANCELLED; } } cp = ans; len = NS_INT16SZ; while ((n = read(statp->_vcsock, (char *)cp, (int)len)) > 0) { cp += n; if ((len -= n) <= 0) break; } if (n <= 0) { *terrno = errno; Perror(statp, stderr, "read failed", errno); res_nclose(statp); /* * A long running process might get its TCP * connection reset if the remote server was * restarted. Requery the server instead of * trying a new one. When there is only one * server, this means that a query might work * instead of failing. We only allow one reset * per query to prevent looping. */ if (*terrno == ECONNRESET && !connreset) { connreset = 1; res_nclose(statp); goto vc_same_ns; } res_nclose(statp); return DNS_RES_STATUS_CONNECTION_FAILED; } resplen = ns_get16(ans); if (resplen > *anssiz) { Dprint(statp->options & RES_DEBUG, (stdout, ";; response truncated\n")); truncating = 1; len = *anssiz; } else { len = resplen; } if (len < NS_HFIXEDSZ) { /* * Undersized message. */ Dprint(statp->options & RES_DEBUG, (stdout, ";; undersized: %d\n", len)); *terrno = EMSGSIZE; res_nclose(statp); *anssiz = 0; return DNS_RES_STATUS_INVALID_REPLY; } cp = ans; while (len != 0 && (n = read(statp->_vcsock, (char *)cp, (int)len)) > 0) { cp += n; len -= n; } if (n <= 0) { *terrno = errno; Perror(statp, stderr, "read(vc)", errno); res_nclose(statp); return DNS_RES_STATUS_CONNECTION_FAILED; } if (truncating) { /* * Flush rest of answer so connection stays in synch. */ anhp->tc = 1; len = resplen - *anssiz; while (len != 0) { char junk[NS_PACKETSZ]; n = read(statp->_vcsock, junk, (len > sizeof junk) ? sizeof junk : len); if (n > 0) len -= n; else break; } } /* * If the calling applicating has bailed out of * a previous call and failed to arrange to have * the circuit closed or the server has got * itself confused, then drop the packet and * wait for the correct one. */ if (hp->id != anhp->id) { DprintQ((statp->options & RES_DEBUG) || (statp->pfcode & RES_PRF_REPLY), (stdout, ";; old answer (unexpected):\n"), ans, (resplen > *anssiz) ? *anssiz : resplen); goto read_len; } /* * All is well, or the error is fatal. Signal that the * next nameserver ought not be tried. */ *fromlen = sizeof(nsap); memcpy(from, &nsap, *fromlen); *anssiz = resplen; return ns_r_noerror; } static ssize_t internal_recvfrom(int s, void *buf, size_t len, struct sockaddr *from, int *fromlen, int *iface) { struct sockaddr_dl *sdl; struct iovec databuffers = { buf, len }; struct msghdr msg; ssize_t n; struct cmsghdr *cmp; char ancillary[1024], ifname[IF_NAMESIZE]; struct in6_pktinfo *ip6_info; struct sockaddr_in *s4; struct sockaddr_in6 *s6; memset(&msg, 0, sizeof(struct msghdr)); msg.msg_name = (caddr_t)from; msg.msg_namelen = *fromlen; msg.msg_iov = &databuffers; msg.msg_iovlen = 1; msg.msg_control = (caddr_t)&ancillary; msg.msg_controllen = sizeof(ancillary); /* Receive the data */ n = recvmsg(s, &msg, 0); if ((n < 0) || (msg.msg_controllen < sizeof(struct cmsghdr)) || (msg.msg_flags & MSG_CTRUNC)) { return n; } *fromlen = msg.msg_namelen; s4 = (struct sockaddr_in *)from; s6 = (struct sockaddr_in6 *)from; for (cmp = CMSG_FIRSTHDR(&msg); cmp; cmp = CMSG_NXTHDR(&msg, cmp)) { if ((cmp->cmsg_level == IPPROTO_IP) && (cmp->cmsg_type == IP_RECVIF)) { sdl = (struct sockaddr_dl *)CMSG_DATA(cmp); if (sdl->sdl_nlen < IF_NAMESIZE) { memcpy(ifname, sdl->sdl_data, sdl->sdl_nlen); ifname[sdl->sdl_nlen] = 0; *iface = if_nametoindex(ifname); } } else if ((cmp->cmsg_level == IPPROTO_IPV6) && (cmp->cmsg_type == IPV6_PKTINFO)) { ip6_info = (struct in6_pktinfo *)CMSG_DATA(cmp); *iface = ip6_info->ipi6_ifindex; } } return n; } static int send_dg(res_state statp, const u_char *buf, int buflen, u_char *ans, int *anssiz, int *terrno, int ns, int *v_circuit, int *gotsomewhere, struct sockaddr *from, int *fromlen, int notify_token) { const HEADER *hp = (const HEADER *) buf; HEADER *anhp = (HEADER *) ans; const struct sockaddr *nsap; int nsaplen, nfds; struct timespec now, timeout, finish; fd_set dsmask; int iface, rif, status; uint64_t exit_requested; int *interrupt_pipe; #ifndef __APPLE__ struct sockaddr_storage from; ISC_SOCKLEN_T fromlen; #endif int resplen, seconds, ntry, n, s; #ifdef MULTICAST int multicast; #endif interrupt_pipe = NULL; nsap = get_nsaddr(statp, ns); nsaplen = get_salen(nsap); if (EXT(statp).nssocks[ns] == -1) { EXT(statp).nssocks[ns] = socket(nsap->sa_family, SOCK_DGRAM, 0); if (EXT(statp).nssocks[ns] > highestFD) { res_nclose(statp); errno = ENOTSOCK; } if (EXT(statp).nssocks[ns] < 0) { *terrno = errno; Perror(statp, stderr, "socket(dg)", errno); return DNS_RES_STATUS_SYSTEM_ERROR; } bind_random(EXT(statp).nssocks[ns]); #ifndef CANNOT_CONNECT_DGRAM /* * On a 4.3BSD+ machine (client and server, * actually), sending to a nameserver datagram * port with no nameserver will cause an * ICMP port unreachable message to be returned. * If our datagram socket is "connected" to the * server, we get an ECONNREFUSED error on the next * socket operation, and select returns if the * error message is received. We can thus detect * the absence of a nameserver without timing out. */ if (connect(EXT(statp).nssocks[ns], nsap, nsaplen) < 0) { Aerror(statp, stderr, "connect(dg)", errno, nsap, nsaplen); res_nclose(statp); return DNS_RES_STATUS_CONNECTION_REFUSED; } #endif /* !CANNOT_CONNECT_DGRAM */ Dprint(statp->options & RES_DEBUG, (stdout, ";; new DG socket\n")) } s = EXT(statp).nssocks[ns]; rif = 1; setsockopt(s, IPPROTO_IP, IP_RECVIF, &rif, sizeof(int)); setsockopt(s, IPPROTO_IPV6, IPV6_PKTINFO, &rif, sizeof(int)); #ifdef MULTICAST multicast = 0; if ((nsap->sa_family == AF_INET) && (IN_MULTICAST(ntohl(((struct sockaddr_in *)nsap)->sin_addr.s_addr)))) multicast = AF_INET; else if ((nsap->sa_family == AF_INET6) && (IN6_IS_ADDR_MULTICAST(&((struct sockaddr_in6 *)nsap)->sin6_addr))) multicast = AF_INET6; if (multicast != 0) { struct ifaddrs *ifa, *p; struct sockaddr_in *sin4; struct sockaddr_in6 *sin6; int i, ifnum; if (getifaddrs(&ifa) < 0) { Aerror(statp, stderr, "getifaddrs", errno, nsap, nsaplen); res_nclose(statp); return DNS_RES_STATUS_SYSTEM_ERROR; } for (p = ifa; p != NULL; p = p->ifa_next) { if (p->ifa_addr == NULL) continue; if ((p->ifa_flags & IFF_UP) == 0) continue; if (p->ifa_addr->sa_family != multicast) continue; if ((p->ifa_flags & IFF_MULTICAST) == 0) continue; if ((p->ifa_flags & IFF_POINTOPOINT) != 0) { if ((multicast == AF_INET) && (ntohl(((struct sockaddr_in *)nsap)->sin_addr.s_addr) <= INADDR_MAX_LOCAL_GROUP)) continue; } sin4 = (struct sockaddr_in *)p->ifa_addr; sin6 = (struct sockaddr_in6 *)p->ifa_addr; i = -1; if (multicast == AF_INET) i = setsockopt(s, IPPROTO_IP, IP_MULTICAST_IF, &sin4->sin_addr, sizeof(sin4->sin_addr)); else if (multicast == AF_INET6) { ifnum = if_nametoindex(p->ifa_name); ((struct sockaddr_in6 *)nsap)->sin6_scope_id = ifnum; i = setsockopt(s, IPPROTO_IPV6, IPV6_MULTICAST_IF, &ifnum, sizeof(ifnum)); } if (i < 0) { Aerror(statp, stderr, "setsockopt", errno, nsap, nsaplen); if (multicast == AF_INET6) ((struct sockaddr_in6 *)nsap)->sin6_scope_id = 0; continue; } if (sendto(s, (const char*)buf, buflen, 0, nsap, nsaplen) != buflen) { Aerror(statp, stderr, "sendto", errno, nsap, nsaplen); if (multicast == AF_INET6) ((struct sockaddr_in6 *)nsap)->sin6_scope_id = 0; continue; } if (multicast == AF_INET6) ((struct sockaddr_in6 *)nsap)->sin6_scope_id = 0; } freeifaddrs(ifa); } else { #endif /* MULTICAST */ #ifndef CANNOT_CONNECT_DGRAM if (send(s, (const char*)buf, buflen, 0) != buflen) { Perror(statp, stderr, "send", errno); res_nclose(statp); return DNS_RES_STATUS_CONNECTION_FAILED; } #else /* !CANNOT_CONNECT_DGRAM */ if (sendto(s, (const char*)buf, buflen, 0, nsap, nsaplen) != buflen) { Aerror(statp, stderr, "sendto", errno, nsap, nsaplen); res_nclose(statp); return DNS_RES_STATUS_CONNECTION_FAILED; } #endif /* !CANNOT_CONNECT_DGRAM */ #ifdef MULTICAST } #endif /* MULTICAST */ /* * Wait for reply. */ #ifdef __APPLE__ ntry = statp->nscount * statp->retry; seconds = statp->retrans / ntry; if (seconds <= 0) seconds = 1; timeout.tv_sec = seconds; timeout.tv_nsec = ((statp->retrans - (seconds * ntry)) * 1000) / ntry; timeout.tv_nsec *= 1000000; now = evNowTime(); finish = evAddTime(now, timeout); if (interrupt_pipe_enabled != 0) interrupt_pipe = pthread_getspecific(interrupt_pipe_key); #else seconds = (statp->retrans << ns); if (ns > 0) seconds /= statp->nscount; if (seconds <= 0) seconds = 1; now = evNowTime(); timeout = evConsTime(seconds, 0); finish = evAddTime(now, timeout); #endif /* __APPLE__ */ goto nonow; wait: now = evNowTime(); nonow: if (notify_token != -1) { exit_requested = 0; status = notify_get_state(notify_token, &exit_requested); if (exit_requested == ThreadStateExitRequested) { Dprint(statp->options & RES_DEBUG, (stdout, ";; cancelled\n")); return DNS_RES_STATUS_CANCELLED; } } FD_ZERO(&dsmask); FD_SET(s, &dsmask); nfds = s + 1; if ((interrupt_pipe_enabled != 0) && (interrupt_pipe != NULL)) { if (interrupt_pipe[0] >= 0) { FD_SET(interrupt_pipe[0], &dsmask); nfds = MAX(s, interrupt_pipe[0]) + 1; } } if (evCmpTime(finish, now) > 0) timeout = evSubTime(finish, now); else timeout = evConsTime(0, 0); #ifdef USE_DNS_PSELECT n = dns_pselect(nfds, &dsmask, NULL, NULL, &timeout, NULL); #else n = pselect(nfds, &dsmask, NULL, NULL, &timeout, NULL); #endif if (n == 0) { Dprint(statp->options & RES_DEBUG, (stdout, ";; timeout\n")); *gotsomewhere = 1; return DNS_RES_STATUS_TIMEOUT; } if (n < 0) { if (errno == EINTR) goto wait; Perror(statp, stderr, "select", errno); res_nclose(statp); return DNS_RES_STATUS_SYSTEM_ERROR; } /* socket s and/or interrupt pipe got data */ if ((interrupt_pipe_enabled != 0) && (interrupt_pipe != NULL) && ((interrupt_pipe[0] < 0) || (FD_ISSET(interrupt_pipe[0], &dsmask)))) { Dprint(statp->options & RES_DEBUG, (stdout, ";; cancelled\n")); return DNS_RES_STATUS_CANCELLED; } errno = 0; iface = 0; resplen = internal_recvfrom(s, (char *)ans, *anssiz, from, fromlen, &iface); if (resplen <= 0) { Perror(statp, stderr, "recvfrom", errno); res_nclose(statp); return DNS_RES_STATUS_CONNECTION_FAILED; } if (nsap->sa_family == AF_INET) memcpy(((struct sockaddr_in *)from)->sin_zero, &iface, 4); else if (nsap->sa_family == AF_INET6) ((struct sockaddr_in6 *)from)->sin6_scope_id = iface; *gotsomewhere = 1; if (resplen < NS_HFIXEDSZ) { /* * Undersized message. */ Dprint(statp->options & RES_DEBUG, (stdout, ";; undersized: %d\n", resplen)); *terrno = EMSGSIZE; res_nclose(statp); return DNS_RES_STATUS_INVALID_REPLY; } if (hp->id != anhp->id) { /* * response from old query, ignore it. * XXX - potential security hazard could * be detected here. */ DprintQ((statp->options & RES_DEBUG) || (statp->pfcode & RES_PRF_REPLY), (stdout, ";; old answer:\n"), ans, (resplen > *anssiz) ? *anssiz : resplen); goto wait; } #ifdef MULTICAST if (multicast == 0) { #endif /* MULTICAST */ if (!(statp->options & RES_INSECURE1) && !res_ourserver_p(statp, from)) { /* * response from wrong server? ignore it. * XXX - potential security hazard could * be detected here. */ DprintQ((statp->options & RES_DEBUG) || (statp->pfcode & RES_PRF_REPLY), (stdout, ";; not our server:\n"), ans, (resplen > *anssiz) ? *anssiz : resplen); goto wait; } #ifdef MULTICAST } #endif /* MULTICAST */ #ifdef RES_USE_EDNS0 if (anhp->rcode == ns_r_formerr && (statp->options & RES_USE_EDNS0) != 0) { /* * Do not retry if the server do not understand EDNS0. * The case has to be captured here, as FORMERR packet do not * carry query section, hence res_queriesmatch() returns 0. */ DprintQ(statp->options & RES_DEBUG, (stdout, "server rejected query with EDNS0:\n"), ans, (resplen > *anssiz) ? *anssiz : resplen); /* record the error */ statp->_flags |= RES_F_EDNS0ERR; res_nclose(statp); return DNS_RES_STATUS_CONNECTION_REFUSED; } #endif if (!(statp->options & RES_INSECURE2) && !res_queriesmatch(buf, buf + buflen, ans, ans + *anssiz)) { /* * response contains wrong query? ignore it. * XXX - potential security hazard could * be detected here. */ DprintQ((statp->options & RES_DEBUG) || (statp->pfcode & RES_PRF_REPLY), (stdout, ";; wrong query name:\n"), ans, (resplen > *anssiz) ? *anssiz : resplen); res_nclose(statp); return DNS_RES_STATUS_INVALID_REPLY; } if (anhp->rcode == ns_r_servfail || anhp->rcode == ns_r_notimpl || anhp->rcode == ns_r_refused) { DprintQ(statp->options & RES_DEBUG, (stdout, "server rejected query:\n"), ans, (resplen > *anssiz) ? *anssiz : resplen); res_nclose(statp); /* don't retry if called from dig */ if (!statp->pfcode) return anhp->rcode; } if (!(statp->options & RES_IGNTC) && anhp->tc) { /* * To get the rest of answer, * use TCP with same server. */ Dprint(statp->options & RES_DEBUG, (stdout, ";; truncated answer\n")); *v_circuit = 1; res_nclose(statp); return ns_r_noerror; } /* * All is well, or the error is fatal. Signal that the * next nameserver ought not be tried. */ *anssiz = resplen; return ns_r_noerror; } static void Aerror(const res_state statp, FILE *file, const char *string, int error, const struct sockaddr *address, int alen) { int save = errno; char hbuf[NI_MAXHOST]; char sbuf[NI_MAXSERV]; if ((statp->options & RES_DEBUG) != 0) { if (getnameinfo(address, alen, hbuf, sizeof(hbuf), sbuf, sizeof(sbuf), niflags)) { strncpy(hbuf, "?", sizeof(hbuf) - 1); hbuf[sizeof(hbuf) - 1] = '\0'; strncpy(sbuf, "?", sizeof(sbuf) - 1); sbuf[sizeof(sbuf) - 1] = '\0'; } fprintf(file, "res_send: %s ([%s].%s): %s\n", string, hbuf, sbuf, strerror(error)); } errno = save; } static void Perror(const res_state statp, FILE *file, const char *string, int error) { int save = errno; if ((statp->options & RES_DEBUG) != 0) fprintf(file, "res_send: %s: %s\n", string, strerror(error)); errno = save; } static int sock_eq(struct sockaddr *a, struct sockaddr *b) { struct sockaddr_in *a4, *b4; struct sockaddr_in6 *a6, *b6; if (a->sa_family != b->sa_family) return 0; switch (a->sa_family) { case AF_INET: a4 = (struct sockaddr_in *)a; b4 = (struct sockaddr_in *)b; return a4->sin_port == b4->sin_port && a4->sin_addr.s_addr == b4->sin_addr.s_addr; case AF_INET6: a6 = (struct sockaddr_in6 *)a; b6 = (struct sockaddr_in6 *)b; return a6->sin6_port == b6->sin6_port && #ifdef HAVE_SIN6_SCOPE_ID a6->sin6_scope_id == b6->sin6_scope_id && #endif IN6_ARE_ADDR_EQUAL(&a6->sin6_addr, &b6->sin6_addr); default: return 0; } } #ifdef USE_DNS_PSELECT static int dns_pselect(int nfds, void *rfds, void *wfds, void *efds, struct timespec *tsp, const sigset_t *sigmask) { struct timeval tv, *tvp = NULL; sigset_t sigs; int n; if (tsp) { tvp = &tv; tv = evTimeVal(*tsp); } if (sigmask) sigprocmask(SIG_SETMASK, sigmask, &sigs); n = select(nfds, rfds, wfds, efds, tvp); if (sigmask) sigprocmask(SIG_SETMASK, &sigs, NULL); if (tsp) *tsp = evTimeSpec(tv); return n; } #endif