/* * 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. 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) 1996-2001 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 1.3 2003/08/07 09:21:10 agc Exp $"; #endif /* LIBC_SCCS and not lint */ /* Rename the I/O functions in case we're tracing. */ #define send trace_mr_send #define recvfrom trace_mr_recvfrom #define read trace_mr_read #define connect trace_mr_connect #define socket trace_mr_socket #define bind trace_mr_bind #define close trace_mr_close #define select trace_mr_select #define time trace_mr_time /* * Send query to name server and wait for reply. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "minires/minires.h" #include "arpa/nameser.h" #define CHECK_SRVR_ADDR static int cmpsock(struct sockaddr_in *a1, struct sockaddr_in *a2); void res_pquery(const res_state, const u_char *, int, FILE *); /* 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(((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 = getUShort(cp); cp += INT16SZ; tclass = getUShort(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(((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 = getUShort(cp); cp += INT16SZ; tclass = getUShort(cp); cp += INT16SZ; if (!res_nameinquery(tname, ttype, tclass, buf2, eom2)) return (0); } return (1); } isc_result_t res_nsend(res_state statp, double *buf, unsigned buflen, double *ans, unsigned anssiz, unsigned *ansret) { HEADER *hp = (HEADER *) buf; HEADER *anhp = (HEADER *) ans; int gotsomewhere, connreset, terrno, try, v_circuit, resplen, ns, n; u_int badns; /* XXX NSMAX can't exceed #/bits in this variable */ static int highestFD = FD_SETSIZE - 1; if (anssiz < HFIXEDSZ) { return ISC_R_INVALIDARG; } 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; connreset = 0; terrno = ISC_R_TIMEDOUT; badns = 0; /* * Some callers want to even out the load on their resolver list. */ if (statp->nscount > 0 && (statp->options & RES_ROTATE) != 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; } #if defined (TRACING) trace_mr_statp_setup (statp); #endif /* * 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 (badns & (1 << ns)) { res_nclose(statp); goto next_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 ISC_R_UNEXPECTED; } } while (!done); } Dprint(statp->options & RES_DEBUG, (stdout, ";; Querying server (# %d) address = %s\n", ns + 1, inet_ntoa(nsap->sin_addr))); if (v_circuit) { int truncated; struct iovec iov[2]; u_short len; u_char *cp; /* Use VC; at most one attempt per server. */ try = statp->retry; truncated = 0; /* Are we still talking to whom we want to talk to? */ if (statp->_sock >= 0 && (statp->_flags & RES_F_VC) != 0) { struct sockaddr_in peer; SOCKLEN_T size = sizeof(peer); if (getpeername(statp->_sock, (struct sockaddr *)&peer, &size) < 0) { res_nclose(statp); statp->_flags &= ~RES_F_VC; } else if (!cmpsock(&peer, nsap)) { res_nclose(statp); statp->_flags &= ~RES_F_VC; } } if (statp->_sock < 0 || (statp->_flags & RES_F_VC) == 0) { if (statp->_sock >= 0) res_nclose(statp); statp->_sock = socket(PF_INET, SOCK_STREAM, 0); if (statp->_sock < 0 || statp->_sock > highestFD) { terrno = uerr2isc (errno); Perror(statp, stderr, "socket(vc)", errno); return (-1); } errno = 0; if (connect(statp->_sock, (struct sockaddr *)nsap, sizeof *nsap) < 0) { terrno = uerr2isc (errno); Aerror(statp, stderr, "connect/vc", errno, *nsap); badns |= (1 << ns); res_nclose(statp); goto next_ns; } statp->_flags |= RES_F_VC; } /* * Send length & message */ putUShort((u_char*)&len, buflen); iov[0].iov_base = (caddr_t)&len; iov[0].iov_len = INT16SZ; iov[1].iov_base = (const caddr_t)buf; iov[1].iov_len = buflen; if (writev(statp->_sock, iov, 2) != (INT16SZ + buflen)) { terrno = uerr2isc (errno); Perror(statp, stderr, "write failed", errno); badns |= (1 << ns); res_nclose(statp); goto next_ns; } /* * Receive length & response */ read_len: cp = (u_char *)ans; len = INT16SZ; while ((n = read(statp->_sock, (char *)cp, (unsigned)len)) > 0) { cp += n; if ((len -= n) <= 0) break; } if (n <= 0) { terrno = uerr2isc (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 == ISC_R_CONNREFUSED && !connreset) { connreset = 1; res_nclose(statp); goto same_ns; } res_nclose(statp); goto next_ns; } resplen = getUShort ((unsigned char *)ans); if (resplen > anssiz) { Dprint(statp->options & RES_DEBUG, (stdout, ";; response truncated\n") ); truncated = 1; len = anssiz; } else len = resplen; if (len < HFIXEDSZ) { /* * Undersized message. */ Dprint(statp->options & RES_DEBUG, (stdout, ";; undersized: %d\n", len)); terrno = ISC_R_NOSPACE; badns |= (1 << ns); res_nclose(statp); goto next_ns; } cp = (u_char *)ans; while (len != 0 && (n = read(statp->_sock, (char *)cp, (unsigned)len)) > 0) { cp += n; len -= n; } if (n <= 0) { terrno = uerr2isc (errno); Perror(statp, stderr, "read(vc)", errno); res_nclose(statp); goto next_ns; } if (truncated) { /* * Flush rest of answer * so connection stays in synch. */ anhp->tc = 1; len = resplen - anssiz; while (len != 0) { char junk[PACKETSZ]; n = (len > sizeof(junk) ? sizeof(junk) : len); n = read(statp->_sock, junk, (unsigned)n); if (n > 0) len -= n; else break; } } /* * 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. Anyway 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; } } else { /* * Use datagrams. */ int start, timeout, finish; fd_set dsmask; struct sockaddr_in from; SOCKLEN_T fromlen; int seconds; if (statp->_sock < 0 || (statp->_flags & RES_F_VC) != 0) { if ((statp->_flags & RES_F_VC) != 0) res_nclose(statp); statp->_sock = socket(PF_INET, SOCK_DGRAM, 0); if (statp->_sock < 0 || statp->_sock > highestFD) { #ifndef CAN_RECONNECT bad_dg_sock: #endif terrno = uerr2isc (errno); Perror(statp, stderr, "socket(dg)", errno); return terrno; } statp->_flags &= ~RES_F_CONN; } #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 we have sent queries to at least two servers, * however, we don't want to remain connected, * as we wish to receive answers from the first * server to respond. */ if (statp->nscount == 1 || (try == 0 && ns == 0)) { /* * Connect only if we are sure we won't * receive a response from another server. */ if ((statp->_flags & RES_F_CONN) == 0) { if (connect(statp->_sock, (struct sockaddr *)nsap, sizeof *nsap) < 0) { Aerror(statp, stderr, "connect(dg)", errno, *nsap); badns |= (1 << ns); res_nclose(statp); goto next_ns; } statp->_flags |= RES_F_CONN; } if (send(statp->_sock, (const char*)buf, (unsigned)buflen, 0) != buflen) { Perror(statp, stderr, "send", errno); badns |= (1 << ns); res_nclose(statp); goto next_ns; } } else { /* * Disconnect if we want to listen * for responses from more than one server. */ if ((statp->_flags & RES_F_CONN) != 0) { #ifdef CAN_RECONNECT struct sockaddr_in no_addr; no_addr.sin_family = AF_INET; no_addr.sin_addr.s_addr = INADDR_ANY; no_addr.sin_port = 0; (void) connect(statp->_sock, (struct sockaddr *) &no_addr, sizeof no_addr); #else struct sockaddr_in local_addr; SOCKLEN_T len; int result, s1; len = sizeof(local_addr); s1 = socket(PF_INET, SOCK_DGRAM, 0); result = getsockname(statp->_sock, (struct sockaddr *)&local_addr, &len); if (s1 < 0) goto bad_dg_sock; (void) dup2(s1, statp->_sock); (void) close(s1); if (result == 0) { /* * Attempt to rebind to old * port. Note connected socket * has an sin_addr set. */ local_addr.sin_addr.s_addr = htonl(0); (void)bind(statp->_sock, (struct sockaddr *) &local_addr, (unsigned)len); } Dprint(statp->options & RES_DEBUG, (stdout, ";; new DG socket\n")); #endif /* CAN_RECONNECT */ statp->_flags &= ~RES_F_CONN; errno = 0; } #endif /* !CANNOT_CONNECT_DGRAM */ if (sendto(statp->_sock, (const char *)buf, buflen, 0, (struct sockaddr *)nsap, sizeof *nsap) != buflen) { Aerror(statp, stderr, "sendto", errno, *nsap); badns |= (1 << ns); res_nclose(statp); goto next_ns; } #ifndef CANNOT_CONNECT_DGRAM } #endif /* !CANNOT_CONNECT_DGRAM */ if (statp->_sock < 0 || statp->_sock > highestFD) { Perror(statp, stderr, "fd out-of-bounds", EMFILE); res_nclose(statp); goto next_ns; } /* * Wait for reply */ seconds = (statp->retrans << try); if (try > 0) seconds /= statp->nscount; if (seconds <= 0) seconds = 1; start = cur_time; timeout = seconds; finish = start + timeout; wait: FD_ZERO(&dsmask); FD_SET(statp->_sock, &dsmask); { struct timeval t; t.tv_sec = timeout; t.tv_usec = 0; n = select(statp->_sock + 1, &dsmask, NULL, NULL, &t); } if (n == 0) { Dprint(statp->options & RES_DEBUG, (stdout, ";; timeout\n")); gotsomewhere = 1; goto next_ns; } if (n < 0) { if (errno == EINTR) { if (finish >= cur_time) { timeout = finish - cur_time; goto wait; } } Perror(statp, stderr, "select", errno); res_nclose(statp); goto next_ns; } errno = 0; fromlen = sizeof(struct sockaddr_in); resplen = recvfrom(statp->_sock, (char *)ans, anssiz, 0, (struct sockaddr *)&from, &fromlen); if (resplen <= 0) { Perror(statp, stderr, "recvfrom", errno); res_nclose(statp); goto next_ns; } gotsomewhere = 1; if (resplen < HFIXEDSZ) { /* * Undersized message. */ Dprint(statp->options & RES_DEBUG, (stdout, ";; undersized: %d\n", resplen)); terrno = ISC_R_NOSPACE; badns |= (1 << ns); res_nclose(statp); goto next_ns; } 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 CHECK_SRVR_ADDR 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; } #endif if (!(statp->options & RES_INSECURE2) && !res_queriesmatch((u_char *)buf, ((u_char *)buf) + buflen, (u_char *)ans, ((u_char *)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); badns |= (1 << ns); res_nclose(statp); /* don't retry if called from dig */ if (!statp->pfcode) goto next_ns; } if (!(statp->options & RES_IGNTC) && anhp->tc) { /* * get rest of answer; * use TCP with same server. */ Dprint(statp->options & RES_DEBUG, (stdout, ";; truncated answer\n")); v_circuit = 1; res_nclose(statp); goto same_ns; } } /*if vc/dg*/ 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 using virtual circuits, we assume that the first server * is preferred over the rest (i.e. it is on the local * machine) and only keep that one open. * 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) || ns != 0)) || !(statp->options & RES_STAYOPEN)) { 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 ISC_R_UNEXPECTED; } } while (!done); } *ansret = resplen; return ISC_R_SUCCESS; next_ns: ; } /*foreach ns*/ } /*foreach retry*/ res_nclose(statp); if (!v_circuit) { if (!gotsomewhere) terrno = ISC_R_CONNREFUSED; /* no nameservers found */ else errno = ISC_R_TIMEDOUT; /* no answer obtained */ } return terrno; } /* * This routine is for closing the socket if a virtual circuit is used and * the program wants to close it. This provides support for endhostent() * which expects to close the socket. * * This routine is not expected to be user visible. */ void res_nclose(res_state statp) { if (statp->_sock >= 0) { (void) close(statp->_sock); statp->_sock = -1; statp->_flags &= ~(RES_F_VC | RES_F_CONN); } } /* Private */ static int cmpsock(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