diff options
Diffstat (limited to 'resolv/res_send.c')
| -rw-r--r-- | resolv/res_send.c | 1069 |
1 files changed, 531 insertions, 538 deletions
diff --git a/resolv/res_send.c b/resolv/res_send.c index d3dc2ba..bf500b1 100644 --- a/resolv/res_send.c +++ b/resolv/res_send.c @@ -1,7 +1,7 @@ /* * 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: @@ -13,7 +13,7 @@ * 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 @@ -29,14 +29,14 @@ /* * 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 @@ -66,7 +66,7 @@ #if defined(LIBC_SCCS) && !defined(lint) static const char sccsid[] = "@(#)res_send.c 8.1 (Berkeley) 6/4/93"; -static const char rcsid[] = "$Id$"; +static const char rcsid[] = "$BINDId: res_send.c,v 8.38 2000/03/30 20:16:51 vixie Exp $"; #endif /* LIBC_SCCS and not lint */ /* @@ -78,6 +78,9 @@ static const char rcsid[] = "$Id$"; #include <sys/time.h> #include <sys/socket.h> #include <sys/uio.h> +#ifdef _LIBC +#include <sys/poll.h> +#endif #include <netinet/in.h> #include <arpa/nameser.h> @@ -92,32 +95,36 @@ static const char rcsid[] = "$Id$"; #include <string.h> #include <unistd.h> -#include <sys/poll.h> +#ifndef _LIBC +#include <isc/eventlib.h> +#else -/* Options. Leave them on. */ -/* #undef DEBUG */ -#include "res_debug.h" +/* From ev_streams.c. */ + +static inline struct iovec +evConsIovec(void *buf, size_t cnt) { + struct iovec ret; -#ifdef NEED_PSELECT -static int pselect(int, void *, void *, void *, - struct timespec *, - const sigset_t *); -#endif + memset(&ret, 0xf5, sizeof ret); + ret.iov_base = buf; + ret.iov_len = cnt; + return (ret); +} -#define CHECK_SRVR_ADDR +/* From ev_timers.c. */ -/* From bind lib/isc/ev_timers.c: */ #define BILLION 1000000000 -static struct timespec + +static inline struct timespec evTimeSpec(struct timeval tv) { - struct timespec ts; + struct timespec ts; - ts.tv_sec = tv.tv_sec; - ts.tv_nsec = tv.tv_usec * 1000; - return (ts); + ts.tv_sec = tv.tv_sec; + ts.tv_nsec = tv.tv_usec * 1000; + return (ts); } -static struct timespec +static inline struct timespec evConsTime(time_t sec, long nsec) { struct timespec x; @@ -126,7 +133,7 @@ evConsTime(time_t sec, long nsec) { return (x); } -static struct timespec +static inline struct timespec evAddTime(struct timespec addend1, struct timespec addend2) { struct timespec x; @@ -139,7 +146,7 @@ evAddTime(struct timespec addend1, struct timespec addend2) { return (x); } -static struct timespec +static inline struct timespec evSubTime(struct timespec minuend, struct timespec subtrahend) { struct timespec x; @@ -153,7 +160,7 @@ evSubTime(struct timespec minuend, struct timespec subtrahend) { return (x); } -static int +static inline int evCmpTime(struct timespec a, struct timespec b) { long x = a.tv_sec - b.tv_sec; @@ -162,7 +169,7 @@ evCmpTime(struct timespec a, struct timespec b) { return (x < 0L ? (-1) : x > 0L ? (1) : (0)); } -static struct timespec +static inline struct timespec evNowTime() { struct timeval now; @@ -170,41 +177,44 @@ evNowTime() { return (evConsTime(0, 0)); return (evTimeSpec(now)); } -/* End of code from bind lib/isc/ev_timers.c. */ -#ifdef DEBUG - static void - Aerror(const res_state statp, FILE *file, const char *string, int error, - struct sockaddr_in address) - { - int save = errno; +#endif - if ((statp->options & RES_DEBUG) != 0) { - char tmp[sizeof "255.255.255.255"]; +/* Options. Leave them on. */ +/* #undef DEBUG */ +#include "res_debug.h" - 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)); - } - __set_errno (save); - } - static void - Perror(const res_state statp, FILE *file, const char *string, int error) { - int save = errno; +#define EXT(res) ((res)->_u._ext) - if ((statp->options & RES_DEBUG) != 0) - fprintf(file, "res_send: %s: %s\n", - string, strerror(error)); - __set_errno (save); - } +#ifndef _LIBC +static const int highestFD = FD_SETSIZE - 1; #endif -static int cmpsock(struct sockaddr_in *a1, struct sockaddr_in *a2); +/* 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 *); +#ifdef DEBUG +static void Aerror(const res_state, FILE *, const char *, int, + struct sockaddr_in); +static void Perror(const res_state, FILE *, const char *, int); +#endif +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[] @@ -220,7 +230,7 @@ res_ourserver_p(const res_state statp, const struct sockaddr_in *inp) { int ns; ina = *inp; - for (ns = 0; ns < statp->nscount; ns++) { + for (ns = 0; ns < statp->nscount; ns++) { const struct sockaddr_in *srv = &statp->nsaddr_list[ns]; if (srv->sin_family == ina.sin_family && @@ -295,8 +305,8 @@ res_queriesmatch(const u_char *buf1, const u_char *eom1, * Only header section present in replies to * dynamic update packets. */ - if ( (((HEADER *)buf1)->opcode == ns_o_update) && - (((HEADER *)buf2)->opcode == ns_o_update) ) + if ((((HEADER *)buf1)->opcode == ns_o_update) && + (((HEADER *)buf2)->opcode == ns_o_update)) return (1); if (qdcount != ntohs(((HEADER*)buf2)->qdcount)) @@ -323,12 +333,12 @@ int res_nsend(res_state statp, const u_char *buf, int buflen, u_char *ans, int anssiz) { - 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; + 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); @@ -337,14 +347,46 @@ res_nsend(res_state statp, (stdout, ";; res_send()\n"), buf, buflen); v_circuit = (statp->options & RES_USEVC) || buflen > PACKETSZ; gotsomewhere = 0; - connreset = 0; terrno = ETIMEDOUT; - badns = 0; /* - * Some callers want to even out the load on their resolver list. + * If the ns_addr_list in the resolver context has changed, then + * invalidate our cached copy and the associated timing data. */ - if (statp->nscount > 0 && (statp->options & RES_ROTATE) != 0) { + 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; @@ -355,17 +397,12 @@ res_nsend(res_state statp, } /* - * Send request, RETRY times, or until successful + * 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; @@ -401,474 +438,45 @@ res_nsend(res_state statp, 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; - int 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 = errno; - Perror(statp, stderr, - "socket(vc)", errno); - return (-1); - } - __set_errno (0); - if (connect(statp->_sock, - (struct sockaddr *)nsap, - sizeof *nsap) < 0) { - terrno = 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 - */ - putshort((u_short)buflen, (u_char*)&len); - iov[0].iov_base = (caddr_t)&len; - iov[0].iov_len = INT16SZ; - iov[1].iov_base = (caddr_t)buf; - iov[1].iov_len = buflen; - if (writev(statp->_sock, iov, 2) != - (INT16SZ + buflen)) { - terrno = errno; - Perror(statp, stderr, "write failed", errno); - badns |= (1 << ns); - res_nclose(statp); + n = send_vc(statp, buf, buflen, ans, anssiz, &terrno, + ns); + if (n < 0) + return (-1); + if (n == 0) goto next_ns; - } - /* - * Receive length & response - */ - read_len: - cp = ans; - len = INT16SZ; - while ((n = read(statp->_sock, - (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); - goto next_ns; - } - resplen = ns_get16(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 = EMSGSIZE; - badns |= (1 << ns); - res_nclose(statp); - goto next_ns; - } - cp = ans; - while (len != 0 && - (n = read(statp->_sock, (char *)cp, (int)len)) - > 0) { - cp += n; - len -= n; - } - if (n <= 0) { - terrno = 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 = ((size_t)len > sizeof(junk) - ? sizeof(junk) - : len); - n = read(statp->_sock, junk, 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; - } + resplen = n; } else { - /* - * Use datagrams. - */ - struct timespec start, timeout, finish; -#ifdef _LIBC - struct pollfd pfd[1]; - int ptimeout; -#else - fd_set dsmask; -#endif - struct sockaddr_in from; - int fromlen, 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 = errno; - Perror(statp, stderr, - "socket(dg)", errno); - return (-1); - } - 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, (char*)buf, 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; - int len, 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, len); - } - Dprint(statp->options & RES_DEBUG, - (stdout, ";; new DG socket\n")) -#endif /* CAN_RECONNECT */ - statp->_flags &= ~RES_F_CONN; - __set_errno (0); - } -#endif /* !CANNOT_CONNECT_DGRAM */ - if (sendto(statp->_sock, - (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); + /* 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; - } - - /* - * Wait for reply - */ - seconds = (statp->retrans << try); - if (try > 0) - seconds /= statp->nscount; - if (seconds <= 0) - seconds = 1; - - start = evNowTime(); - timeout = evConsTime(seconds, 0); - finish = evAddTime(start, timeout); - wait: -#ifdef _LIBC - /* Convert struct timespec in milliseconds. */ - ptimeout = timeout.tv_sec * 1000 - + timeout.tv_nsec / 1000000; - - pfd[0].fd = statp->_sock; - pfd[0].events = POLLIN; - n = __poll (pfd, 1, ptimeout); -#else - FD_ZERO(&dsmask); - FD_SET(statp->_sock, &dsmask); - n = pselect(statp->_sock + 1, - &dsmask, NULL, NULL, - &timeout, NULL); -#endif - if (n == 0) { - Dprint(statp->options & RES_DEBUG, - (stdout, ";; timeout\n")); - gotsomewhere = 1; - goto next_ns; - } - if (n < 0) { - if (errno == EINTR) { - struct timespec now; - - now = evNowTime(); - if (evCmpTime(finish, now) >= 0) { - timeout = evSubTime(finish, - now); - goto wait; - } - } -#ifdef _LIBC - Perror(statp, stderr, "poll", errno); -#else - Perror(statp, stderr, "select", errno); -#endif - res_nclose(statp); - goto next_ns; - } - __set_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 = EMSGSIZE; - 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(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); - 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); + if (v_circuit) goto same_ns; - } - } /*if vc/dg*/ + 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); + 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)) { + if ((v_circuit && (statp->options & RES_USEVC) == 0) || + (statp->options & RES_STAYOPEN) == 0) { res_nclose(statp); } if (statp->rhook) { @@ -915,25 +523,411 @@ res_nsend(res_state statp, return (-1); } -/* - * 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 +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); +#ifndef _LIBC + if (statp->_vcsock > highestFD) { + res_nclose(statp); + __set_errno (ENOTSOCK); + } +#endif + if (statp->_vcsock < 0) { + *terrno = errno; + Perror(statp, stderr, "socket(vc)", errno); + return (-1); + } + __set_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); } -/* Private */ static int -cmpsock(struct sockaddr_in *a1, struct sockaddr_in *a2) { +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; +#ifdef _LIBC + struct pollfd pfd[1]; + int ptimeout; +#else + fd_set dsmask; +#endif + 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); +#ifndef _LIBC + if (EXT(statp).nssocks[ns] > highestFD) { + res_nclose(statp); + __set_errno (ENOTSOCK); + } +#endif + 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: +#ifdef _LIBC + /* Convert struct timespec in milliseconds. */ + ptimeout = timeout.tv_sec * 1000 + timeout.tv_nsec / 1000000; + + pfd[0].fd = s; + pfd[0].events = POLLIN; + n = __poll (pfd, 1, ptimeout); +#else + FD_ZERO(&dsmask); + FD_SET(s, &dsmask); + n = pselect(s + 1, &dsmask, NULL, NULL, &timeout, NULL); +#endif + 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); + } + __set_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); +} + +#ifdef DEBUG +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)); + } + __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_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)); @@ -943,8 +937,7 @@ cmpsock(struct sockaddr_in *a1, struct sockaddr_in *a2) { /* 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 timespec *tsp, const sigset_t *sigmask) { struct timeval tv, *tvp; sigset_t sigs; |