diff options
Diffstat (limited to 'resolv/res_send.c')
| -rw-r--r-- | resolv/res_send.c | 746 |
1 files changed, 746 insertions, 0 deletions
diff --git a/resolv/res_send.c b/resolv/res_send.c new file mode 100644 index 0000000000..03055d3619 --- /dev/null +++ b/resolv/res_send.c @@ -0,0 +1,746 @@ +/* + * ++Copyright++ 1985, 1989, 1993 + * - + * 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. + * - + * --Copyright-- + */ + +#if defined(LIBC_SCCS) && !defined(lint) +static char sccsid[] = "@(#)res_send.c 8.1 (Berkeley) 6/4/93"; +static char rcsid[] = "$Id$"; +#endif /* LIBC_SCCS and not lint */ + + /* change this to "0" + * if you talk to a lot + * of multi-homed SunOS + * ("broken") name servers. + */ +#define CHECK_SRVR_ADDR 1 /* XXX - should be in options.h */ + +/* + * Send query to name server and wait for reply. + */ + +#include <sys/param.h> +#include <sys/time.h> +#include <sys/socket.h> +#include <sys/uio.h> +#include <netinet/in.h> +#include <arpa/nameser.h> +#include <arpa/inet.h> + +#include <stdio.h> +#include <errno.h> +#include <resolv.h> +#if defined(BSD) && (BSD >= 199306) +# include <stdlib.h> +# include <string.h> +#else +# include "../conf/portability.h" +#endif + +#if defined(USE_OPTIONS_H) +# include <../conf/options.h> +#endif + +void _res_close __P((void)); + +static int s = -1; /* socket used for communications */ +static int connected = 0; /* is the socket connected */ +static int vc = 0; /* is the socket a virtual ciruit? */ + +#ifndef FD_SET +/* XXX - should be in portability.h */ +#define NFDBITS 32 +#define FD_SETSIZE 32 +#define FD_SET(n, p) ((p)->fds_bits[(n)/NFDBITS] |= (1 << ((n) % NFDBITS))) +#define FD_CLR(n, p) ((p)->fds_bits[(n)/NFDBITS] &= ~(1 << ((n) % NFDBITS))) +#define FD_ISSET(n, p) ((p)->fds_bits[(n)/NFDBITS] & (1 << ((n) % NFDBITS))) +#define FD_ZERO(p) bzero((char *)(p), sizeof(*(p))) +#endif + +#ifndef DEBUG +# define Dprint(cond, args) /*empty*/ +# define DprintQ(cond, args, query) /*empty*/ +# define Aerror(file, string, error, address) /*empty*/ +# define Perror(file, string, error) /*empty*/ +#else +# define Dprint(cond, args) if (cond) {fprintf args;} else {} +# define DprintQ(cond, args, query) if (cond) {\ + fprintf args;\ + __p_query(query);\ + } else {} + static void + Aerror(file, string, error, address) + FILE *file; + char *string; + int error; + struct sockaddr_in address; + { + int save = errno; + + if (_res.options & RES_DEBUG) { + fprintf(file, "res_send: %s ([%s].%u): %s\n", + string, + inet_ntoa(address.sin_addr), + ntohs(address.sin_port), + strerror(error)); + } + errno = save; + } + static void + Perror(file, string, error) + FILE *file; + char *string; + int error; + { + int save = errno; + + if (_res.options & RES_DEBUG) { + fprintf(file, "res_send: %s: %s\n", + string, strerror(error)); + } + errno = save; + } +#endif + +static res_send_qhook Qhook = NULL; +static res_send_rhook Rhook = NULL; + +void +res_send_setqhook(hook) + res_send_qhook hook; +{ + + Qhook = hook; +} + +void +res_send_setrhook(hook) + res_send_rhook hook; +{ + + Rhook = hook; +} + +/* int + * res_isourserver(ina) + * looks up "ina" in _res.ns_addr_list[] + * returns: + * 0 : not found + * >0 : found + * author: + * paul vixie, 29may94 + */ +int +res_isourserver(inp) + const struct sockaddr_in *inp; +{ + struct sockaddr_in ina; + register int ns, ret; + + ina = *inp; + ret = 0; + for (ns = 0; ns < _res.nscount; ns++) { + register const struct sockaddr_in *srv = &_res.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)) { + ret++; + break; + } + } + return (ret); +} + +/* int + * res_nameinquery(name, type, class, buf, eom) + * look for (name,type,class) in the query section of packet (buf,eom) + * returns: + * -1 : format error + * 0 : not found + * >0 : found + * author: + * paul vixie, 29may94 + */ +int +res_nameinquery(name, type, class, buf, eom) + const char *name; + register int type, class; + const u_char *buf, *eom; +{ + register const u_char *cp = buf + HFIXEDSZ; + int qdcount = ntohs(((HEADER*)buf)->qdcount); + + while (qdcount-- > 0) { + char tname[MAXDNAME+1]; + register int n, ttype, tclass; + + n = dn_expand(buf, eom, cp, tname, sizeof tname); + if (n < 0) + return (-1); + cp += n; + ttype = _getshort(cp); cp += INT16SZ; + tclass = _getshort(cp); cp += INT16SZ; + if (ttype == type && + tclass == class && + strcasecmp(tname, name) == 0) + 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(buf1, eom1, buf2, eom2) + const u_char *buf1, *eom1; + const u_char *buf2, *eom2; +{ + register const u_char *cp = buf1 + HFIXEDSZ; + int qdcount = ntohs(((HEADER*)buf1)->qdcount); + + if (qdcount != ntohs(((HEADER*)buf2)->qdcount)) + return (0); + while (qdcount-- > 0) { + char tname[MAXDNAME+1]; + register int n, ttype, tclass; + + n = dn_expand(buf1, eom1, cp, tname, sizeof tname); + if (n < 0) + return (-1); + cp += n; + ttype = _getshort(cp); cp += INT16SZ; + tclass = _getshort(cp); cp += INT16SZ; + if (!res_nameinquery(tname, ttype, tclass, buf2, eom2)) + return (0); + } + return (1); +} + +int +res_send(buf, buflen, ans, anssiz) + 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; + register int n; + u_int badns; /* XXX NSMAX can't exceed #/bits in this var */ + + DprintQ((_res.options & RES_DEBUG) || (_res.pfcode & RES_PRF_QUERY), + (stdout, ";; res_send()\n"), buf); + if (!(_res.options & RES_INIT) && res_init() == -1) + return (-1); + v_circuit = (_res.options & RES_USEVC) || buflen > PACKETSZ; + gotsomewhere = 0; + connreset = 0; + terrno = ETIMEDOUT; + badns = 0; + + /* + * Send request, RETRY times, or until successful + */ + for (try = 0; try < _res.retry; try++) { + for (ns = 0; ns < _res.nscount; ns++) { + struct sockaddr_in *nsap = &_res.nsaddr_list[ns]; + same_ns: + if (badns & (1 << ns)) { + _res_close(); + goto next_ns; + } + + if (Qhook) { + int done = 0, loops = 0; + + do { + res_sendhookact act; + + act = (*Qhook)(&nsap, &buf, &buflen, + ans, anssiz, &resplen); + switch (act) { + case res_goahead: + done = 1; + break; + case res_nextns: + _res_close(); + 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(_res.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 virtual circuit; + * at most one attempt per server. + */ + try = _res.retry; + truncated = 0; + if ((s < 0) || (!vc)) { + if (s >= 0) + _res_close(); + + s = socket(AF_INET, SOCK_STREAM, PF_UNSPEC); + if (s < 0) { + terrno = errno; + Perror(stderr, "socket(vc)", errno); + return (-1); + } + if (connect(s, (struct sockaddr *)nsap, + sizeof(struct sockaddr)) < 0) { + terrno = errno; + Aerror(stderr, "connect/vc", + errno, *nsap); + badns |= (1 << ns); + _res_close(); + goto next_ns; + } + vc = 1; + } + /* + * 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(s, iov, 2) != (INT16SZ + buflen)) { + terrno = errno; + Perror(stderr, "write failed", errno); + badns |= (1 << ns); + _res_close(); + goto next_ns; + } + /* + * Receive length & response + */ + cp = ans; + len = INT16SZ; + while ((n = read(s, (char *)cp, (int)len)) > 0) { + cp += n; + if ((len -= n) <= 0) + break; + } + if (n <= 0) { + terrno = errno; + Perror(stderr, "read failed", errno); + _res_close(); + /* + * 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_close(); + goto same_ns; + } + _res_close(); + goto next_ns; + } + resplen = _getshort(ans); + if (resplen > anssiz) { + Dprint(_res.options & RES_DEBUG, + (stdout, ";; response truncated\n") + ); + truncated = 1; + len = anssiz; + } else + len = resplen; + cp = ans; + while (len != 0 && + (n = read(s, (char *)cp, (int)len)) > 0) { + cp += n; + len -= n; + } + if (n <= 0) { + terrno = errno; + Perror(stderr, "read(vc)", errno); + _res_close(); + 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); + if ((n = read(s, junk, n)) > 0) + len -= n; + else + break; + } + } + } else { + /* + * Use datagrams. + */ + struct timeval timeout; + fd_set dsmask; + struct sockaddr_in from; + int fromlen; + + if ((s < 0) || vc) { + if (vc) + _res_close(); + s = socket(AF_INET, SOCK_DGRAM, PF_UNSPEC); + if (s < 0) { + bad_dg_sock: terrno = errno; + Perror(stderr, "socket(dg)", errno); + return (-1); + } + connected = 0; + } + /* + * 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 (_res.nscount == 1 || (try == 0 && ns == 0)) { + /* + * Connect only if we are sure we won't + * receive a response from another server. + */ + if (!connected) { + if (connect(s, (struct sockaddr *)nsap, + sizeof(struct sockaddr) + ) < 0) { + Aerror(stderr, + "connect(dg)", + errno, *nsap); + badns |= (1 << ns); + _res_close(); + goto next_ns; + } + connected = 1; + } + if (send(s, (char*)buf, buflen, 0) != buflen) { + Perror(stderr, "send", errno); + badns |= (1 << ns); + _res_close(); + goto next_ns; + } + } else { + /* + * Disconnect if we want to listen + * for responses from more than one server. + */ + if (connected) { +#if defined(BSD) && (BSD >= 199103) + 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(s, + (struct sockaddr *) + &no_addr, + sizeof(no_addr)); +#else + int s1 = socket(AF_INET, SOCK_DGRAM, + PF_UNSPEC); + if (s1 < 0) + goto bad_dg_sock; + (void) dup2(s1, s); + (void) close(s1); + Dprint(_res.options & RES_DEBUG, + (stdout, ";; new DG socket\n")) +#endif + connected = 0; + errno = 0; + } + if (sendto(s, (char*)buf, buflen, 0, + (struct sockaddr *)nsap, + sizeof(struct sockaddr)) + != buflen) { + Aerror(stderr, "sendto", errno, *nsap); + badns |= (1 << ns); + _res_close(); + goto next_ns; + } + } + + /* + * Wait for reply + */ + timeout.tv_sec = (_res.retrans << try); + if (try > 0) + timeout.tv_sec /= _res.nscount; + if ((long) timeout.tv_sec <= 0) + timeout.tv_sec = 1; + timeout.tv_usec = 0; + wait: + FD_ZERO(&dsmask); + FD_SET(s, &dsmask); + n = select(s+1, &dsmask, (fd_set *)NULL, + (fd_set *)NULL, &timeout); + if (n < 0) { + Perror(stderr, "select", errno); + _res_close(); + goto next_ns; + } + if (n == 0) { + /* + * timeout + */ + Dprint(_res.options & RES_DEBUG, + (stdout, ";; timeout\n")); + gotsomewhere = 1; + _res_close(); + goto next_ns; + } + fromlen = sizeof(struct sockaddr_in); + resplen = recvfrom(s, (char*)ans, anssiz, 0, + (struct sockaddr *)&from, &fromlen); + if (resplen <= 0) { + Perror(stderr, "recvfrom", errno); + _res_close(); + goto next_ns; + } + gotsomewhere = 1; + if (hp->id != anhp->id) { + /* + * response from old query, ignore it. + * XXX - potential security hazard could + * be detected here. + */ + DprintQ((_res.options & RES_DEBUG) || + (_res.pfcode & RES_PRF_REPLY), + (stdout, ";; old answer:\n"), + ans); + goto wait; + } +#if CHECK_SRVR_ADDR + if (!(_res.options & RES_INSECURE1) && + !res_isourserver(&from)) { + /* + * response from wrong server? ignore it. + * XXX - potential security hazard could + * be detected here. + */ + DprintQ((_res.options & RES_DEBUG) || + (_res.pfcode & RES_PRF_REPLY), + (stdout, ";; not our server:\n"), + ans); + goto wait; + } +#endif + if (!(_res.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((_res.options & RES_DEBUG) || + (_res.pfcode & RES_PRF_REPLY), + (stdout, ";; wrong query name:\n"), + ans); + goto wait; + } + if (anhp->rcode == SERVFAIL || + anhp->rcode == NOTIMP || + anhp->rcode == REFUSED) { + DprintQ(_res.options & RES_DEBUG, + (stdout, "server rejected query:\n"), + ans); + badns |= (1 << ns); + _res_close(); + /* don't retry if called from dig */ + if (!_res.pfcode) + goto next_ns; + } + if (!(_res.options & RES_IGNTC) && anhp->tc) { + /* + * get rest of answer; + * use TCP with same server. + */ + Dprint(_res.options & RES_DEBUG, + (stdout, ";; truncated answer\n")); + v_circuit = 1; + _res_close(); + goto same_ns; + } + } /*if vc/dg*/ + DprintQ((_res.options & RES_DEBUG) || + (_res.pfcode & RES_PRF_REPLY), + (stdout, ";; got answer:\n"), + ans); + /* + * 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 && (!(_res.options & RES_USEVC) || ns != 0)) || + !(_res.options & RES_STAYOPEN)) { + _res_close(); + } + if (Rhook) { + int done = 0, loops = 0; + + do { + res_sendhookact act; + + act = (*Rhook)(nsap, buf, buflen, + ans, anssiz, &resplen); + switch (act) { + case res_goahead: + case res_done: + done = 1; + break; + case res_nextns: + _res_close(); + 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_close(); + if (!v_circuit) + if (!gotsomewhere) + errno = ECONNREFUSED; /* no nameservers found */ + else + errno = ETIMEDOUT; /* no answer obtained */ + else + errno = terrno; + 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_close() +{ + if (s >= 0) { + (void) close(s); + s = -1; + connected = 0; + vc = 0; + } +} |