/* * Portions Copyright (C) 2004-2009 Internet Systems Consortium, Inc. ("ISC") * Portions Copyright (C) 1996-2003 Internet Software Consortium. * * Permission to use, copy, modify, and/or 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 ISC DISCLAIMS ALL WARRANTIES WITH * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY * AND FITNESS. IN NO EVENT SHALL ISC 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. */ /* * 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. */ #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 1.22 2009/01/22 23:49:23 tbox Exp $"; #endif /* LIBC_SCCS and not lint */ #include __FBSDID("$FreeBSD$"); /*! \file * \brief * Send query to name server and wait for reply. */ #include "port_before.h" #if !defined(USE_KQUEUE) && !defined(USE_POLL) #include "fd_setsize.h" #endif #include "namespace.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "port_after.h" #ifdef USE_KQUEUE #include #else #ifdef USE_POLL #ifdef HAVE_STROPTS_H #include #endif #include #endif /* USE_POLL */ #endif #include "un-namespace.h" /* Options. Leave them on. */ #define DEBUG #include "res_debug.h" #include "res_private.h" #define EXT(res) ((res)->_u._ext) #if !defined(USE_POLL) && !defined(USE_KQUEUE) static const int highestFD = FD_SETSIZE - 1; #endif /* Forward. */ static int get_salen(const struct sockaddr *); static struct sockaddr * get_nsaddr(res_state, size_t); static int send_vc(res_state, const u_char *, int, u_char *, int, int *, int); static int send_dg(res_state, #ifdef USE_KQUEUE int kq, #endif const u_char *, int, u_char *, int, int *, int, int, 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 *); #if defined(NEED_PSELECT) && !defined(USE_POLL) && !defined(USE_KQUEUE) static int pselect(int, void *, void *, void *, struct timespec *, const sigset_t *); #endif void res_pquery(const res_state, const u_char *, int, FILE *); static const int niflags = NI_NUMERICHOST | NI_NUMERICSERV; /* Public. */ /*% * looks up "ina" in _res.ns_addr_list[] * * returns: *\li 0 : not found *\li >0 : found * * author: *\li 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 && #ifdef HAVE_SIN6_SCOPE_ID (srv6->sin6_scope_id == 0 || srv6->sin6_scope_id == in6p->sin6_scope_id) && #endif (IN6_IS_ADDR_UNSPECIFIED(&srv6->sin6_addr) || IN6_ARE_ADDR_EQUAL(&srv6->sin6_addr, &in6p->sin6_addr))) return (1); } break; default: break; } return (0); } /*% * look for (name,type,class) in the query section of packet (buf,eom) * * requires: *\li buf + HFIXEDSZ <= eom * * returns: *\li -1 : format error *\li 0 : not found *\li >0 : found * * author: *\li 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(((const 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); ttype = ns_get16(cp); cp += INT16SZ; tclass = ns_get16(cp); cp += INT16SZ; if (ttype == type && tclass == class && ns_samename(tname, name) == 1) return (1); } return (0); } /*% * is there a 1:1 mapping of (name,type,class) * in (buf1,eom1) and (buf2,eom2)? * * returns: *\li -1 : format error *\li 0 : not a 1:1 mapping *\li >0 : is a 1:1 mapping * * author: *\li 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 + HFIXEDSZ; int qdcount = ntohs(((const HEADER*)buf1)->qdcount); if (buf1 + HFIXEDSZ > eom1 || buf2 + 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[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); ttype = ns_get16(cp); cp += INT16SZ; tclass = ns_get16(cp); cp += INT16SZ; if (!res_nameinquery(tname, ttype, tclass, buf2, eom2)) return (0); } return (1); } int res_nsend(res_state statp, const u_char *buf, int buflen, u_char *ans, int anssiz) { int gotsomewhere, terrno, tries, v_circuit, resplen, ns, n; #ifdef USE_KQUEUE int kq; #endif char abuf[NI_MAXHOST]; /* No name servers or res_init() failure */ if (statp->nscount == 0 || EXT(statp).ext == NULL) { errno = ESRCH; return (-1); } if (anssiz < HFIXEDSZ) { errno = EINVAL; return (-1); } 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; #ifdef USE_KQUEUE if ((kq = kqueue()) < 0) { Perror(statp, stderr, "kqueue", errno); return (-1); } #endif /* * 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 && !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 (_getpeername(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; 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) != 0U && (statp->options & RES_BLAST) == 0U) { 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; } /* * Send request, RETRY times, or until successful. */ for (tries = 0; tries < statp->retry; tries++) { for (ns = 0; ns < statp->nscount; ns++) { struct sockaddr *nsap; int nsaplen; nsap = get_nsaddr(statp, ns); nsaplen = get_salen(nsap); statp->_flags &= ~RES_F_LASTMASK; statp->_flags |= (ns << RES_F_LASTSHIFT); same_ns: if (statp->qhook) { int done = 0, loops = 0; do { res_sendhookact act; act = (*statp->qhook)(&nsap, &buf, &buflen, ans, anssiz, &resplen); switch (act) { case res_goahead: done = 1; break; case res_nextns: res_nclose(statp); goto next_ns; case res_done: #ifdef USE_KQUEUE _close(kq); #endif return (resplen); case res_modified: /* give the hook another try */ if (++loops < 42) /*doug adams*/ break; /*FALLTHROUGH*/ case res_error: /*FALLTHROUGH*/ default: goto fail; } } while (!done); } 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)); if (v_circuit) { /* Use VC; at most one attempt per server. */ tries = statp->retry; n = send_vc(statp, buf, buflen, ans, anssiz, &terrno, ns); if (n < 0) goto fail; if (n == 0) goto next_ns; resplen = n; } else { /* Use datagrams. */ n = send_dg(statp, #ifdef USE_KQUEUE kq, #endif buf, buflen, ans, anssiz, &terrno, ns, tries, &v_circuit, &gotsomewhere); if (n < 0) goto fail; 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) == 0U) || (statp->options & RES_STAYOPEN) == 0U) { 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 next_ns; case res_modified: /* give the hook another try */ if (++loops < 42) /*doug adams*/ break; /*FALLTHROUGH*/ case res_error: /*FALLTHROUGH*/ default: goto fail; } } while (!done); } #ifdef USE_KQUEUE _close(kq); #endif return (resplen); next_ns: ; } /*foreach ns*/ } /*foreach retry*/ res_nclose(statp); #ifdef USE_KQUEUE _close(kq); #endif if (!v_circuit) { if (!gotsomewhere) errno = ECONNREFUSED; /*%< no nameservers found */ else errno = ETIMEDOUT; /*%< no answer obtained */ } else errno = terrno; return (-1); fail: res_nclose(statp); #ifdef USE_KQUEUE _close(kq); #endif return (-1); } /* 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. */ static struct sockaddr * get_nsaddr(res_state statp, size_t n) { if (!statp->nsaddr_list[n].sin_family && EXT(statp).ext) { /* * - 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) { 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; #ifdef SO_NOSIGPIPE int on = 1; #endif nsap = get_nsaddr(statp, ns); nsaplen = get_salen(nsap); 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_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 | SOCK_CLOEXEC, 0); #if !defined(USE_POLL) && !defined(USE_KQUEUE) if (statp->_vcsock > highestFD) { res_nclose(statp); errno = ENOTSOCK; } #endif if (statp->_vcsock < 0) { switch (errno) { case EPROTONOSUPPORT: #ifdef EPFNOSUPPORT case EPFNOSUPPORT: #endif case EAFNOSUPPORT: Perror(statp, stderr, "socket(vc)", errno); return (0); default: *terrno = errno; Perror(statp, stderr, "socket(vc)", errno); return (-1); } } #ifdef SO_NOSIGPIPE /* * Disable generation of SIGPIPE when writing to a closed * socket. Write should return -1 and set errno to EPIPE * instead. * * Push on even if setsockopt(SO_NOSIGPIPE) fails. */ (void)_setsockopt(statp->_vcsock, SOL_SOCKET, SO_NOSIGPIPE, &on, sizeof(on)); #endif errno = 0; if (_connect(statp->_vcsock, nsap, nsaplen) < 0) { *terrno = errno; Aerror(statp, stderr, "connect/vc", errno, nsap, nsaplen); res_nclose(statp); return (0); } statp->_flags |= RES_F_VC; } /* * Send length & message */ ns_put16((u_short)buflen, (u_char*)&len); iov[0] = evConsIovec(&len, INT16SZ); DE_CONST(buf, tmp); iov[1] = evConsIovec(tmp, buflen); if (_writev(statp->_vcsock, iov, 2) != (INT16SZ + buflen)) { *terrno = errno; Perror(statp, stderr, "write failed", errno); res_nclose(statp); return (0); } /* * Receive length & response */ read_len: cp = ans; len = 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 same_ns; } res_nclose(statp); return (0); } 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 < HFIXEDSZ) { /* * Undersized message. */ Dprint(statp->options & RES_DEBUG, (stdout, ";; undersized: %d\n", len)); *terrno = EMSGSIZE; res_nclose(statp); 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_nclose(statp); 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, #ifdef USE_KQUEUE int kq, #endif const u_char *buf, int buflen, u_char *ans, int anssiz, int *terrno, int ns, int tries, int *v_circuit, int *gotsomewhere) { const HEADER *hp = (const HEADER *) buf; HEADER *anhp = (HEADER *) ans; const struct sockaddr *nsap; int nsaplen; struct timespec now, timeout, finish; struct sockaddr_storage from; ISC_SOCKLEN_T fromlen; int resplen, seconds, n, s; #ifdef USE_KQUEUE struct kevent kv; #else #ifdef USE_POLL int polltimeout; struct pollfd pollfd; #else fd_set dsmask; #endif #endif 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 | SOCK_CLOEXEC, 0); #if !defined(USE_POLL) && !defined(USE_KQUEUE) if (EXT(statp).nssocks[ns] > highestFD) { res_nclose(statp); errno = ENOTSOCK; } #endif if (EXT(statp).nssocks[ns] < 0) { switch (errno) { case EPROTONOSUPPORT: #ifdef EPFNOSUPPORT case EPFNOSUPPORT: #endif case EAFNOSUPPORT: Perror(statp, stderr, "socket(dg)", errno); return (0); default: *terrno = errno; Perror(statp, stderr, "socket(dg)", errno); return (-1); } } #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. * * When the option "insecure1" is specified, we'd * rather expect to see responses from an "unknown" * address. In order to let the kernel accept such * responses, do not connect the socket here. * XXX: or do we need an explicit option to disable * connecting? */ if (!(statp->options & RES_INSECURE1) && _connect(EXT(statp).nssocks[ns], nsap, nsaplen) < 0) { Aerror(statp, stderr, "connect(dg)", errno, nsap, nsaplen); res_nclose(statp); return (0); } #endif /* !CANNOT_CONNECT_DGRAM */ Dprint(statp->options & RES_DEBUG, (stdout, ";; new DG socket\n")) } s = EXT(statp).nssocks[ns]; #ifndef CANNOT_CONNECT_DGRAM if (statp->options & RES_INSECURE1) { if (_sendto(s, (const char*)buf, buflen, 0, nsap, nsaplen) != buflen) { Aerror(statp, stderr, "sendto", errno, nsap, nsaplen); res_nclose(statp); return (0); } } else if (send(s, (const char*)buf, buflen, 0) != buflen) { Perror(statp, stderr, "send", errno); res_nclose(statp); return (0); } #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 (0); } #endif /* !CANNOT_CONNECT_DGRAM */ /* * Wait for reply. */ seconds = (statp->retrans << tries); if (ns > 0) seconds /= statp->nscount; if (seconds <= 0) seconds = 1; now = evNowTime(); timeout = evConsTime(seconds, 0); finish = evAddTime(now, timeout); goto nonow; wait: now = evNowTime(); nonow: #ifndef USE_POLL if (evCmpTime(finish, now) > 0) timeout = evSubTime(finish, now); else timeout = evConsTime(0, 0); #ifdef USE_KQUEUE EV_SET(&kv, s, EVFILT_READ, EV_ADD | EV_ONESHOT, 0, 0, 0); n = _kevent(kq, &kv, 1, &kv, 1, &timeout); #else FD_ZERO(&dsmask); FD_SET(s, &dsmask); n = pselect(s + 1, &dsmask, NULL, NULL, &timeout, NULL); #endif #else timeout = evSubTime(finish, now); if (timeout.tv_sec < 0) timeout = evConsTime(0, 0); polltimeout = 1000*timeout.tv_sec + timeout.tv_nsec/1000000; pollfd.fd = s; pollfd.events = POLLRDNORM; n = _poll(&pollfd, 1, polltimeout); #endif /* USE_POLL */ if (n == 0) { Dprint(statp->options & RES_DEBUG, (stdout, ";; timeout\n")); *gotsomewhere = 1; return (0); } if (n < 0) { if (errno == EINTR) goto wait; #ifdef USE_KQUEUE Perror(statp, stderr, "kevent", errno); #else #ifndef USE_POLL Perror(statp, stderr, "select", errno); #else Perror(statp, stderr, "poll", errno); #endif /* USE_POLL */ #endif res_nclose(statp); return (0); } #ifdef USE_KQUEUE if (kv.ident != s) goto wait; #endif errno = 0; fromlen = sizeof(from); resplen = _recvfrom(s, (char*)ans, anssiz,0, (struct sockaddr *)&from, &fromlen); if (resplen <= 0) { Perror(statp, stderr, "recvfrom", errno); res_nclose(statp); return (0); } *gotsomewhere = 1; if (resplen < HFIXEDSZ) { /* * Undersized message. */ Dprint(statp->options & RES_DEBUG, (stdout, ";; undersized: %d\n", resplen)); *terrno = EMSGSIZE; res_nclose(statp); return (0); } 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, (struct sockaddr *)&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; res_nclose(statp); return (0); } #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); res_nclose(statp); /* don't retry if called from dig */ if (!statp->pfcode) return (0); } 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 (1); } /* * All is well, or the error is fatal. Signal that the * next nameserver ought not be tried. */ return (resplen); } 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) != 0U) { 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) != 0U) 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; } } #if defined(NEED_PSELECT) && !defined(USE_POLL) && !defined(USE_KQUEUE) /* XXX needs to move to the porting library. */ static int pselect(int nfds, void *rfds, void *wfds, void *efds, struct timespec *tsp, const sigset_t *sigmask) { struct timeval tv, *tvp; sigset_t sigs; int n; if (tsp) { tvp = &tv; tv = evTimeVal(*tsp); } else tvp = NULL; 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