/* * 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 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 "port_before.h" #include "fd_setsize.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "port_after.h" /* Options. Leave them on. */ #define DEBUG #include "res_debug.h" #define EXT(res) ((res)->_u._ext) static const int highestFD = FD_SETSIZE - 1; /* Forward. */ static int send_vc(res_state, const u_char *, int, u_char *, int, int *, int); static int send_dg(res_state, const u_char *, int, u_char *, int, int *, int, int *, int *); static void Aerror(const res_state, FILE *, const char *, int, struct sockaddr_in); static void Perror(const res_state, FILE *, const char *, int); static int sock_eq(struct sockaddr_in *, struct sockaddr_in *); #ifdef NEED_PSELECT static int pselect(int, void *, void *, void *, struct timespec *, const sigset_t *); #endif /* Reachover. */ 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_in *inp) { struct sockaddr_in ina; int ns; ina = *inp; for (ns = 0; ns < statp->nscount; ns++) { const struct sockaddr_in *srv = &statp->nsaddr_list[ns]; if (srv->sin_family == ina.sin_family && srv->sin_port == ina.sin_port && (srv->sin_addr.s_addr == INADDR_ANY || srv->sin_addr.s_addr == ina.sin_addr.s_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); 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); } /* 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 + HFIXEDSZ; int qdcount = ntohs(((HEADER*)buf1)->qdcount); 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); if (qdcount != ntohs(((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, try, v_circuit, resplen, ns, n; if (statp->nscount == 0) { 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; /* * 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; if (EXT(statp).nscount != statp->nscount) needclose++; else for (ns = 0; ns < statp->nscount; ns++) if (!sock_eq(&statp->nsaddr_list[ns], &EXT(statp).nsaddrs[ns])) { needclose++; break; } if (needclose) res_nclose(statp); } /* * Maybe initialize our private copy of the ns_addr_list. */ if (EXT(statp).nscount == 0) { for (ns = 0; ns < statp->nscount; ns++) { EXT(statp).nsaddrs[ns] = statp->nsaddr_list[ns]; EXT(statp).nstimes[ns] = RES_MAXTIME; EXT(statp).nssocks[ns] = -1; } 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) { struct sockaddr_in ina; int lastns = statp->nscount - 1; ina = statp->nsaddr_list[0]; for (ns = 0; ns < lastns; ns++) statp->nsaddr_list[ns] = statp->nsaddr_list[ns + 1]; statp->nsaddr_list[lastns] = ina; } /* * Send request, RETRY times, or until successful. */ for (try = 0; try < statp->retry; try++) { for (ns = 0; ns < statp->nscount; ns++) { struct sockaddr_in *nsap = &statp->nsaddr_list[ns]; 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: 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); } Dprint(statp->options & RES_DEBUG, (stdout, ";; Querying server (# %d) address = %s\n", ns + 1, inet_ntoa(nsap->sin_addr))); if (v_circuit) { /* Use VC; at most one attempt per server. */ try = statp->retry; n = send_vc(statp, buf, buflen, ans, anssiz, &terrno, ns); 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); 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, ""), 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_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: return (-1); } } while (!done); } return (resplen); next_ns: ; } /*foreach ns*/ } /*foreach retry*/ res_nclose(statp); if (!v_circuit) { if (!gotsomewhere) errno = ECONNREFUSED; /* no nameservers found */ else errno = ETIMEDOUT; /* no answer obtained */ } else errno = terrno; return (-1); } /* Private */ 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 = (HEADER *) buf; HEADER *anhp = (HEADER *) ans; struct sockaddr_in *nsap = &statp->nsaddr_list[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_in peer; int size = sizeof peer; if (getpeername(statp->_vcsock, (struct sockaddr *)&peer, &size) < 0 || !sock_eq(&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(PF_INET, 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 (-1); } errno = 0; if (connect(statp->_vcsock, (struct sockaddr *)nsap, sizeof *nsap) < 0) { *terrno = errno; Aerror(statp, stderr, "connect/vc", errno, *nsap); res_nclose(statp); return (0); } statp->_flags |= RES_F_VC; } /* * Send length & message */ putshort((u_short)buflen, (u_char*)&len); iov[0] = evConsIovec(&len, INT16SZ); iov[1] = evConsIovec((void*)buf, 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, const u_char *buf, int buflen, u_char *ans, int anssiz, int *terrno, int ns, int *v_circuit, int *gotsomewhere) { const HEADER *hp = (HEADER *) buf; HEADER *anhp = (HEADER *) ans; const struct sockaddr_in *nsap = &statp->nsaddr_list[ns]; struct timespec now, timeout, finish; fd_set dsmask; struct sockaddr_in from; int fromlen, resplen, seconds, n, s; if (EXT(statp).nssocks[ns] == -1) { EXT(statp).nssocks[ns] = socket(PF_INET, 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 (-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. */ if (connect(EXT(statp).nssocks[ns], (struct sockaddr *)nsap, sizeof *nsap) < 0) { Aerror(statp, stderr, "connect(dg)", errno, *nsap); 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 (send(s, (char*)buf, buflen, 0) != buflen) { Perror(statp, stderr, "send", errno); res_nclose(statp); return (0); } #else /* !CANNOT_CONNECT_DGRAM */ if (sendto(s, (char*)buf, buflen, 0, (struct sockaddr *)nsap, sizeof *nsap) != buflen) { Aerror(statp, stderr, "sendto", errno, *nsap); res_nclose(statp); return (0); } #endif /* !CANNOT_CONNECT_DGRAM */ /* * Wait for reply. */ 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); wait: FD_ZERO(&dsmask); FD_SET(s, &dsmask); n = pselect(s + 1, &dsmask, NULL, NULL, &timeout, NULL); if (n == 0) { Dprint(statp->options & RES_DEBUG, (stdout, ";; timeout\n")); *gotsomewhere = 1; return (0); } if (n < 0) { if (errno == EINTR) { now = evNowTime(); if (evCmpTime(finish, now) > 0) { timeout = evSubTime(finish, now); goto wait; } } Perror(statp, stderr, "select", errno); res_nclose(statp); return (0); } errno = 0; fromlen = sizeof(struct sockaddr_in); 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, &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; } 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, struct sockaddr_in address) { int save = errno; if ((statp->options & RES_DEBUG) != 0) { char tmp[sizeof "255.255.255.255"]; fprintf(file, "res_send: %s ([%s].%u): %s\n", string, inet_ntop(address.sin_family, &address.sin_addr, tmp, sizeof tmp), ntohs(address.sin_port), 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_in *a1, struct sockaddr_in *a2) { return ((a1->sin_family == a2->sin_family) && (a1->sin_port == a2->sin_port) && (a1->sin_addr.s_addr == a2->sin_addr.s_addr)); } #ifdef NEED_PSELECT /* 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