/* * 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. * 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[] = "$BINDId: res_send.c,v 8.38 2000/03/30 20:16:51 vixie Exp $"; #endif /* LIBC_SCCS and not lint */ /* * Send query to name server and wait for reply. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #if PACKETSZ > 65536 #define MAXPACKET PACKETSZ #else #define MAXPACKET 65536 #endif /* From ev_streams.c. */ static inline void __attribute ((always_inline)) evConsIovec(void *buf, size_t cnt, struct iovec *vec) { memset(vec, 0xf5, sizeof (*vec)); vec->iov_base = buf; vec->iov_len = cnt; } /* From ev_timers.c. */ #define BILLION 1000000000 static inline void evConsTime(struct timespec *res, time_t sec, long nsec) { res->tv_sec = sec; res->tv_nsec = nsec; } static inline void evAddTime(struct timespec *res, const struct timespec *addend1, const struct timespec *addend2) { res->tv_sec = addend1->tv_sec + addend2->tv_sec; res->tv_nsec = addend1->tv_nsec + addend2->tv_nsec; if (res->tv_nsec >= BILLION) { res->tv_sec++; res->tv_nsec -= BILLION; } } static inline void evSubTime(struct timespec *res, const struct timespec *minuend, const struct timespec *subtrahend) { res->tv_sec = minuend->tv_sec - subtrahend->tv_sec; if (minuend->tv_nsec >= subtrahend->tv_nsec) res->tv_nsec = minuend->tv_nsec - subtrahend->tv_nsec; else { res->tv_nsec = (BILLION - subtrahend->tv_nsec + minuend->tv_nsec); res->tv_sec--; } } static inline 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)); } static inline void evNowTime(struct timespec *res) { struct timeval now; if (gettimeofday(&now, NULL) < 0) evConsTime(res, 0, 0); else TIMEVAL_TO_TIMESPEC (&now, res); } /* Options. Leave them on. */ /* #undef DEBUG */ #include "res_debug.h" #define EXT(res) ((res)->_u._ext) /* Forward. */ static int send_vc(res_state, const u_char *, int, u_char **, int *, int *, int, u_char **); static int send_dg(res_state, const u_char *, int, u_char **, int *, int *, int, int *, int *, u_char **); #ifdef DEBUG static void Aerror(const res_state, FILE *, const char *, int, const struct sockaddr *); static void Perror(const res_state, FILE *, const char *, int); #endif static int sock_eq(struct sockaddr_in6 *, struct sockaddr_in6 *); /* Reachover. */ static void convaddr4to6(struct sockaddr_in6 *sa); void res_pquery(const res_state, const u_char *, int, FILE *); /* 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_in6 *inp) { int ns; if (inp->sin6_family == AF_INET) { struct sockaddr_in *in4p = (struct sockaddr_in *) inp; in_port_t port = in4p->sin_port; in_addr_t addr = in4p->sin_addr.s_addr; for (ns = 0; ns < MAXNS; ns++) { const struct sockaddr_in *srv = (struct sockaddr_in *)EXT(statp).nsaddrs[ns]; if ((srv != NULL) && (srv->sin_family == AF_INET) && (srv->sin_port == port) && (srv->sin_addr.s_addr == INADDR_ANY || srv->sin_addr.s_addr == addr)) return (1); } } else if (inp->sin6_family == AF_INET6) { for (ns = 0; ns < MAXNS; ns++) { const struct sockaddr_in6 *srv = EXT(statp).nsaddrs[ns]; if ((srv != NULL) && (srv->sin6_family == AF_INET6) && (srv->sin6_port == inp->sin6_port) && !(memcmp(&srv->sin6_addr, &in6addr_any, sizeof (struct in6_addr)) && memcmp(&srv->sin6_addr, &inp->sin6_addr, sizeof (struct in6_addr)))) return (1); } } 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 + 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 + HFIXEDSZ; int qdcount = ntohs(((HEADER*)buf)->qdcount); while (qdcount-- > 0) { char tname[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 * INT16SZ > eom) return (-1); NS_GET16(ttype, cp); NS_GET16(tclass, cp); if (ttype == type && tclass == class && ns_samename(tname, name) == 1) return (1); } return (0); } libresolv_hidden_def (res_nameinquery) /* 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) { if (buf1 + HFIXEDSZ > eom1 || buf2 + HFIXEDSZ > eom2) return (-1); /* * Only header section present in replies to * dynamic update packets. */ if ((((HEADER *)buf1)->opcode == ns_o_update) && (((HEADER *)buf2)->opcode == ns_o_update)) return (1); /* Note that we initially do not convert QDCOUNT to the host byte order. We can compare it with the second buffer's QDCOUNT value without doing this. */ int qdcount = ((HEADER*)buf1)->qdcount; if (qdcount != ((HEADER*)buf2)->qdcount) return (0); qdcount = htons (qdcount); const u_char *cp = buf1 + HFIXEDSZ; while (qdcount-- > 0) { char tname[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 * INT16SZ > eom1) return (-1); NS_GET16(ttype, cp); NS_GET16(tclass, cp); if (!res_nameinquery(tname, ttype, tclass, buf2, eom2)) return (0); } return (1); } libresolv_hidden_def (res_queriesmatch) int __libc_res_nsend(res_state statp, const u_char *buf, int buflen, u_char *ans, int anssiz, u_char **ansp) { int gotsomewhere, terrno, try, v_circuit, resplen, ns, n; if (statp->nscount == 0) { __set_errno (ESRCH); return (-1); } if (anssiz < HFIXEDSZ) { __set_errno (EINVAL); return (-1); } if ((statp->qhook || statp->rhook) && anssiz < MAXPACKET && ansp) { u_char *buf = malloc (MAXPACKET); if (buf == NULL) return (-1); memcpy (buf, ans, HFIXEDSZ); *ansp = buf; ans = buf; anssiz = MAXPACKET; } DprintQ((statp->options & RES_DEBUG) || (statp->pfcode & RES_PRF_QUERY), (stdout, ";; res_send()\n"), buf, buflen); v_circuit = (statp->options & RES_USEVC) || buflen > PACKETSZ; gotsomewhere = 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).nsinit) { int needclose = 0; if (EXT(statp).nscount != statp->nscount) needclose++; else for (ns = 0; ns < MAXNS; ns++) { unsigned int map = EXT(statp).nsmap[ns]; if (map < MAXNS && !sock_eq((struct sockaddr_in6 *) &statp->nsaddr_list[map], EXT(statp).nsaddrs[ns])) { needclose++; break; } } if (needclose) __res_iclose(statp, false); } /* * Maybe initialize our private copy of the ns_addr_list. */ if (EXT(statp).nsinit == 0) { unsigned char map[MAXNS]; memset (map, MAXNS, sizeof (map)); for (n = 0; n < MAXNS; n++) { ns = EXT(statp).nsmap[n]; if (ns < statp->nscount) map[ns] = n; else if (ns < MAXNS) { free(EXT(statp).nsaddrs[n]); EXT(statp).nsaddrs[n] = NULL; EXT(statp).nsmap[n] = MAXNS; } } n = statp->nscount; if (statp->nscount > EXT(statp).nscount) for (n = EXT(statp).nscount, ns = 0; n < statp->nscount; n++) { while (ns < MAXNS && EXT(statp).nsmap[ns] != MAXNS) ns++; if (ns == MAXNS) break; EXT(statp).nsmap[ns] = n; map[n] = ns++; } EXT(statp).nscount = n; for (ns = 0; ns < EXT(statp).nscount; ns++) { n = map[ns]; if (EXT(statp).nsaddrs[n] == NULL) EXT(statp).nsaddrs[n] = malloc(sizeof (struct sockaddr_in6)); if (EXT(statp).nsaddrs[n] != NULL) { memset (mempcpy(EXT(statp).nsaddrs[n], &statp->nsaddr_list[ns], sizeof (struct sockaddr_in)), '\0', sizeof (struct sockaddr_in6) - sizeof (struct sockaddr_in)); EXT(statp).nssocks[n] = -1; n++; } } EXT(statp).nsinit = 1; } /* * 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) { struct sockaddr_in6 *ina; unsigned int map; n = 0; while (n < MAXNS && EXT(statp).nsmap[n] == MAXNS) n++; if (n < MAXNS) { ina = EXT(statp).nsaddrs[n]; map = EXT(statp).nsmap[n]; for (;;) { ns = n + 1; while (ns < MAXNS && EXT(statp).nsmap[ns] == MAXNS) ns++; if (ns == MAXNS) break; EXT(statp).nsaddrs[n] = EXT(statp).nsaddrs[ns]; EXT(statp).nsmap[n] = EXT(statp).nsmap[ns]; n = ns; } EXT(statp).nsaddrs[n] = ina; EXT(statp).nsmap[n] = map; } } /* * Send request, RETRY times, or until successful. */ for (try = 0; try < statp->retry; try++) { for (ns = 0; ns < MAXNS; ns++) { struct sockaddr_in6 *nsap = EXT(statp).nsaddrs[ns]; if (nsap == NULL) goto next_ns; same_ns: if (statp->qhook) { int done = 0, loops = 0; do { res_sendhookact act; struct sockaddr_in *nsap4; nsap4 = (struct sockaddr_in *) nsap; act = (*statp->qhook)(&nsap4, &buf, &buflen, ans, anssiz, &resplen); nsap = (struct sockaddr_in6 *) nsap4; switch (act) { case res_goahead: done = 1; break; case res_nextns: __res_iclose(statp, false); goto next_ns; case res_done: return (resplen); case res_modified: /* give the hook another try */ if (++loops < 42) /*doug adams*/ break; /*FALLTHROUGH*/ case res_error: /*FALLTHROUGH*/ default: return (-1); } } while (!done); } #ifdef DEBUG char tmpbuf[40]; #endif Dprint(statp->options & RES_DEBUG, (stdout, ";; Querying server (# %d) address = %s\n", ns + 1, inet_ntop(AF_INET6, &nsap->sin6_addr, tmpbuf, sizeof (tmpbuf)))); if (v_circuit) { /* Use VC; at most one attempt per server. */ try = statp->retry; n = send_vc(statp, buf, buflen, &ans, &anssiz, &terrno, ns, ansp); if (n < 0) return (-1); if (n == 0) goto next_ns; resplen = n; } else { /* Use datagrams. */ n = send_dg(statp, buf, buflen, &ans, &anssiz, &terrno, ns, &v_circuit, &gotsomewhere, ansp); if (n < 0) return (-1); if (n == 0) goto next_ns; if (v_circuit) goto same_ns; resplen = n; } 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, (resplen > anssiz) ? anssiz : resplen); /* * 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 && (statp->options & RES_USEVC) == 0) || (statp->options & RES_STAYOPEN) == 0) { __res_iclose(statp, false); } if (statp->rhook) { int done = 0, loops = 0; do { res_sendhookact act; act = (*statp->rhook)((struct sockaddr_in *) nsap, buf, buflen, ans, anssiz, &resplen); switch (act) { case res_goahead: case res_done: done = 1; break; case res_nextns: __res_iclose(statp, false); goto next_ns; case res_modified: /* give the hook another try */ if (++loops < 42) /*doug adams*/ break; /*FALLTHROUGH*/ case res_error: /*FALLTHROUGH*/ default: return (-1); } } while (!done); } return (resplen); next_ns: ; } /*foreach ns*/ } /*foreach retry*/ __res_iclose(statp, false); if (!v_circuit) { if (!gotsomewhere) __set_errno (ECONNREFUSED); /* no nameservers found */ else __set_errno (ETIMEDOUT); /* no answer obtained */ } else __set_errno (terrno); return (-1); } int res_nsend(res_state statp, const u_char *buf, int buflen, u_char *ans, int anssiz) { return __libc_res_nsend(statp, buf, buflen, ans, anssiz, NULL); } libresolv_hidden_def (res_nsend) /* Private */ static int send_vc(res_state statp, const u_char *buf, int buflen, u_char **ansp, int *anssizp, int *terrno, int ns, u_char **anscp) { const HEADER *hp = (HEADER *) buf; u_char *ans = *ansp; int anssiz = *anssizp; HEADER *anhp = (HEADER *) ans; struct sockaddr_in6 *nsap = EXT(statp).nsaddrs[ns]; int truncating, connreset, resplen, n; struct iovec iov[2]; u_short len; u_char *cp; connreset = 0; same_ns: truncating = 0; /* Are we still talking to whom we want to talk to? */ if (statp->_vcsock >= 0 && (statp->_flags & RES_F_VC) != 0) { struct sockaddr_in6 peer; socklen_t size = sizeof peer; if (getpeername(statp->_vcsock, (struct sockaddr *)&peer, &size) < 0 || !sock_eq(&peer, nsap)) { __res_iclose(statp, false); statp->_flags &= ~RES_F_VC; } } if (statp->_vcsock < 0 || (statp->_flags & RES_F_VC) == 0) { if (statp->_vcsock >= 0) __res_iclose(statp, false); statp->_vcsock = socket(nsap->sin6_family, SOCK_STREAM, 0); if (statp->_vcsock < 0) { *terrno = errno; Perror(statp, stderr, "socket(vc)", errno); return (-1); } __set_errno (0); if (connect(statp->_vcsock, (struct sockaddr *)nsap, nsap->sin6_family == AF_INET ? sizeof (struct sockaddr_in) : sizeof (struct sockaddr_in6)) < 0) { *terrno = errno; Aerror(statp, stderr, "connect/vc", errno, (struct sockaddr *) nsap); __res_iclose(statp, false); return (0); } statp->_flags |= RES_F_VC; } /* * Send length & message */ ns_put16((u_short)buflen, (u_char*)&len); evConsIovec(&len, INT16SZ, &iov[0]); evConsIovec((void*)buf, buflen, &iov[1]); if (TEMP_FAILURE_RETRY (writev(statp->_vcsock, iov, 2)) != (INT16SZ + buflen)) { *terrno = errno; Perror(statp, stderr, "write failed", errno); __res_iclose(statp, false); return (0); } /* * Receive length & response */ read_len: cp = ans; len = INT16SZ; while ((n = TEMP_FAILURE_RETRY (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_iclose(statp, false); /* * 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; goto same_ns; } return (0); } resplen = ns_get16(ans); if (resplen > anssiz) { if (anscp) { ans = malloc (MAXPACKET); if (ans == NULL) { *terrno = ENOMEM; __res_iclose(statp, false); return (0); } anssiz = MAXPACKET; *anssizp = MAXPACKET; *ansp = ans; *anscp = ans; anhp = (HEADER *) ans; len = resplen; } else { Dprint(statp->options & RES_DEBUG, (stdout, ";; response truncated\n") ); truncating = 1; len = anssiz; } } else len = resplen; if (len < HFIXEDSZ) { /* * Undersized message. */ Dprint(statp->options & RES_DEBUG, (stdout, ";; undersized: %d\n", len)); *terrno = EMSGSIZE; __res_iclose(statp, false); return (0); } 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_iclose(statp, false); return (0); } if (truncating) { /* * Flush rest of answer so connection stays in synch. */ anhp->tc = 1; len = resplen - anssiz; while (len != 0) { char junk[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. */ return (resplen); } static int send_dg(res_state statp, const u_char *buf, int buflen, u_char **ansp, int *anssizp, int *terrno, int ns, int *v_circuit, int *gotsomewhere, u_char **anscp) { const HEADER *hp = (HEADER *) buf; u_char *ans = *ansp; int anssiz = *anssizp; HEADER *anhp = (HEADER *) ans; struct sockaddr_in6 *nsap = EXT(statp).nsaddrs[ns]; struct timespec now, timeout, finish; struct pollfd pfd[1]; int ptimeout; struct sockaddr_in6 from; socklen_t fromlen; int resplen, seconds, n; if (EXT(statp).nssocks[ns] == -1) { /* only try IPv6 if IPv6 NS and if not failed before */ if ((EXT(statp).nscount6 > 0) && !statp->ipv6_unavail) { EXT(statp).nssocks[ns] = socket(PF_INET6, SOCK_DGRAM, 0); if (EXT(statp).nssocks[ns] < 0) statp->ipv6_unavail = errno == EAFNOSUPPORT; /* If IPv6 socket and nsap is IPv4, make it IPv4-mapped */ else if (nsap->sin6_family == AF_INET) convaddr4to6(nsap); } if (EXT(statp).nssocks[ns] < 0) EXT(statp).nssocks[ns] = socket(PF_INET, SOCK_DGRAM, 0); if (EXT(statp).nssocks[ns] < 0) { *terrno = errno; Perror(statp, stderr, "socket(dg)", errno); return (-1); } /* * 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], (struct sockaddr *)nsap, sizeof *nsap) < 0) { Aerror(statp, stderr, "connect(dg)", errno, (struct sockaddr *) nsap); __res_iclose(statp, false); return (0); } /* Make socket non-blocking. */ int fl = __fcntl (EXT(statp).nssocks[ns], F_GETFL); if (fl != -1) __fcntl (EXT(statp).nssocks[ns], F_SETFL, fl | O_NONBLOCK); Dprint(statp->options & RES_DEBUG, (stdout, ";; new DG socket\n")) } /* * Compute time for the total operation. */ seconds = (statp->retrans << ns); if (ns > 0) seconds /= statp->nscount; if (seconds <= 0) seconds = 1; evNowTime(&now); evConsTime(&timeout, seconds, 0); evAddTime(&finish, &now, &timeout); int need_recompute = 0; int nwritten = 0; pfd[0].fd = EXT(statp).nssocks[ns]; pfd[0].events = POLLOUT; wait: if (need_recompute) { recompute_resend: evNowTime(&now); if (evCmpTime(finish, now) <= 0) { poll_err_out: Perror(statp, stderr, "poll", errno); err_out: __res_iclose(statp, false); return (0); } evSubTime(&timeout, &finish, &now); } /* Convert struct timespec in milliseconds. */ ptimeout = timeout.tv_sec * 1000 + timeout.tv_nsec / 1000000; n = 0; if (nwritten == 0) n = __poll (pfd, 1, 0); if (__builtin_expect (n == 0, 0)) { n = __poll (pfd, 1, ptimeout); need_recompute = 1; } if (n == 0) { Dprint(statp->options & RES_DEBUG, (stdout, ";; timeout sending\n")); *gotsomewhere = 1; return (0); } if (n < 0) { if (errno == EINTR) goto recompute_resend; goto poll_err_out; } __set_errno (0); if (pfd[0].revents & POLLOUT) { if (send (pfd[0].fd, buf, buflen, MSG_NOSIGNAL) != buflen) { if (errno == EINTR || errno == EAGAIN) goto recompute_resend; Perror(statp, stderr, "send", errno); goto err_out; } pfd[0].events = POLLIN; ++nwritten; goto wait; } else if (pfd[0].revents & POLLIN) { fromlen = sizeof(struct sockaddr_in6); if (anssiz < MAXPACKET && anscp && (ioctl (pfd[0].fd, FIONREAD, &resplen) < 0 || anssiz < resplen)) { ans = malloc (MAXPACKET); if (ans == NULL) ans = *ansp; else { anssiz = MAXPACKET; *anssizp = MAXPACKET; *ansp = ans; *anscp = ans; anhp = (HEADER *) ans; } } resplen = recvfrom(pfd[0].fd, (char*)ans, anssiz,0, (struct sockaddr *)&from, &fromlen); if (resplen <= 0) { if (errno == EINTR || errno == EAGAIN) { need_recompute = 1; goto wait; } Perror(statp, stderr, "recvfrom", errno); goto err_out; } *gotsomewhere = 1; if (resplen < HFIXEDSZ) { /* * Undersized message. */ Dprint(statp->options & RES_DEBUG, (stdout, ";; undersized: %d\n", resplen)); *terrno = EMSGSIZE; goto err_out; } 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; } 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 RES_USE_EDNS0 if (anhp->rcode == FORMERR && (statp->options & RES_USE_EDNS0) != 0U) { /* * 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; goto err_out; } #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); goto wait; } if (anhp->rcode == SERVFAIL || anhp->rcode == NOTIMP || anhp->rcode == REFUSED) { DprintQ(statp->options & RES_DEBUG, (stdout, "server rejected query:\n"), ans, (resplen > anssiz) ? anssiz : resplen); next_ns: __res_iclose(statp, false); /* don't retry if called from dig */ if (!statp->pfcode) return (0); } if (anhp->rcode == NOERROR && anhp->ancount == 0 && anhp->aa == 0 && anhp->ra == 0 && anhp->arcount == 0) { DprintQ(statp->options & RES_DEBUG, (stdout, "referred query:\n"), ans, (resplen > anssiz) ? anssiz : resplen); goto next_ns; } 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_iclose(statp, false); return (1); } /* * All is well, or the error is fatal. Signal that the * next nameserver ought not be tried. */ return (resplen); } else if (pfd[0].revents & (POLLERR | POLLHUP | POLLNVAL)) { /* Something went wrong. We can stop trying. */ goto err_out; } else { /* poll should not have returned > 0 in this case. */ abort (); } } #ifdef DEBUG static void Aerror(const res_state statp, FILE *file, const char *string, int error, const struct sockaddr *address) { int save = errno; if ((statp->options & RES_DEBUG) != 0) { char tmp[sizeof "xxxx.xxxx.xxxx.255.255.255.255"]; fprintf(file, "res_send: %s ([%s].%u): %s\n", string, (address->sa_family == AF_INET ? inet_ntop(address->sa_family, &((const struct sockaddr_in *) address)->sin_addr, tmp, sizeof tmp) : inet_ntop(address->sa_family, &((const struct sockaddr_in6 *) address)->sin6_addr, tmp, sizeof tmp)), (address->sa_family == AF_INET ? ntohs(((struct sockaddr_in *) address)->sin_port) : address->sa_family == AF_INET6 ? ntohs(((struct sockaddr_in6 *) address)->sin6_port) : 0), strerror(error)); } __set_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)); __set_errno (save); } #endif static int sock_eq(struct sockaddr_in6 *a1, struct sockaddr_in6 *a2) { if (a1->sin6_family == a2->sin6_family) { if (a1->sin6_family == AF_INET) return ((((struct sockaddr_in *)a1)->sin_port == ((struct sockaddr_in *)a2)->sin_port) && (((struct sockaddr_in *)a1)->sin_addr.s_addr == ((struct sockaddr_in *)a2)->sin_addr.s_addr)); else return ((a1->sin6_port == a2->sin6_port) && !memcmp(&a1->sin6_addr, &a2->sin6_addr, sizeof (struct in6_addr))); } if (a1->sin6_family == AF_INET) { struct sockaddr_in6 *sap = a1; a1 = a2; a2 = sap; } /* assumes that AF_INET and AF_INET6 are the only possibilities */ return ((a1->sin6_port == ((struct sockaddr_in *)a2)->sin_port) && IN6_IS_ADDR_V4MAPPED(&a1->sin6_addr) && (a1->sin6_addr.s6_addr32[3] == ((struct sockaddr_in *)a2)->sin_addr.s_addr)); } /* * Converts IPv4 family, address and port to * IPv6 family, IPv4-mapped IPv6 address and port. */ static void convaddr4to6(struct sockaddr_in6 *sa) { struct sockaddr_in *sa4p = (struct sockaddr_in *) sa; in_port_t port = sa4p->sin_port; in_addr_t addr = sa4p->sin_addr.s_addr; sa->sin6_family = AF_INET6; sa->sin6_port = port; sa->sin6_addr.s6_addr32[0] = 0; sa->sin6_addr.s6_addr32[1] = 0; sa->sin6_addr.s6_addr32[2] = htonl(0xFFFF); sa->sin6_addr.s6_addr32[3] = addr; }