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-rw-r--r--lib/libc/net/res_send.c468
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diff --git a/lib/libc/net/res_send.c b/lib/libc/net/res_send.c
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+/*-
+ * 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: res_send.c,v 4.9.1.1 1993/05/02 22:43:03 vixie Rel $";
+#endif /* LIBC_SCCS and not lint */
+
+/*
+ * 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>
+#include <unistd.h>
+#include <string.h>
+
+static int s = -1; /* socket used for communications */
+static struct sockaddr no_addr;
+
+#ifndef FD_SET
+#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
+
+res_send(buf, buflen, answer, anslen)
+ const char *buf;
+ int buflen;
+ char *answer;
+ int anslen;
+{
+ register int n;
+ int try, v_circuit, resplen, ns;
+ int gotsomewhere = 0, connected = 0;
+ int connreset = 0;
+ u_short id, len;
+ char *cp;
+ fd_set dsmask;
+ struct timeval timeout;
+ HEADER *hp = (HEADER *) buf;
+ HEADER *anhp = (HEADER *) answer;
+ u_int badns; /* XXX NSMAX can't exceed #/bits per this */
+ struct iovec iov[2];
+ int terrno = ETIMEDOUT;
+ char junk[512];
+
+#ifdef DEBUG
+ if ((_res.options & RES_DEBUG) || (_res.pfcode & RES_PRF_QUERY)) {
+ printf(";; res_send()\n");
+ __p_query(buf);
+ }
+#endif
+ if (!(_res.options & RES_INIT))
+ if (res_init() == -1) {
+ return(-1);
+ }
+ v_circuit = (_res.options & RES_USEVC) || buflen > PACKETSZ;
+ id = hp->id;
+ badns = 0;
+ /*
+ * Send request, RETRY times, or until successful
+ */
+ for (try = 0; try < _res.retry; try++) {
+ for (ns = 0; ns < _res.nscount; ns++) {
+ if (badns & (1<<ns))
+ continue;
+#ifdef DEBUG
+ if (_res.options & RES_DEBUG)
+ printf(";; Querying server (# %d) address = %s\n",
+ ns+1,
+ inet_ntoa(_res.nsaddr_list[ns].sin_addr));
+#endif
+ usevc:
+ if (v_circuit) {
+ int truncated = 0;
+
+ /*
+ * Use virtual circuit;
+ * at most one attempt per server.
+ */
+ try = _res.retry;
+ if (s < 0) {
+ s = socket(AF_INET, SOCK_STREAM, 0);
+ if (s < 0) {
+ terrno = errno;
+#ifdef DEBUG
+ if (_res.options & RES_DEBUG)
+ perror("socket (vc) failed");
+#endif
+ continue;
+ }
+ if (connect(s,
+ (struct sockaddr *)&(_res.nsaddr_list[ns]),
+ sizeof(struct sockaddr)) < 0) {
+ terrno = errno;
+#ifdef DEBUG
+ if (_res.options & RES_DEBUG)
+ perror("connect failed");
+#endif
+ (void) close(s);
+ s = -1;
+ continue;
+ }
+ }
+ /*
+ * Send length & message
+ */
+ len = htons((u_short)buflen);
+ iov[0].iov_base = (caddr_t)&len;
+ iov[0].iov_len = sizeof(len);
+ iov[1].iov_base = (char *)buf;
+ iov[1].iov_len = buflen;
+ if (writev(s, iov, 2) != sizeof(len) + buflen) {
+ terrno = errno;
+#ifdef DEBUG
+ if (_res.options & RES_DEBUG)
+ perror("write failed");
+#endif
+ (void) close(s);
+ s = -1;
+ continue;
+ }
+ /*
+ * Receive length & response
+ */
+ cp = answer;
+ len = sizeof(short);
+ while (len != 0 &&
+ (n = read(s, (char *)cp, (int)len)) > 0) {
+ cp += n;
+ len -= n;
+ }
+ if (n <= 0) {
+ terrno = errno;
+#ifdef DEBUG
+ if (_res.options & RES_DEBUG)
+ perror("read failed");
+#endif
+ (void) close(s);
+ s = -1;
+ /*
+ * 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;
+ ns--;
+ }
+ continue;
+ }
+ cp = answer;
+ if ((resplen = ntohs(*(u_short *)cp)) > anslen) {
+#ifdef DEBUG
+ if (_res.options & RES_DEBUG)
+ fprintf(stderr,
+ ";; response truncated\n");
+#endif
+ len = anslen;
+ truncated = 1;
+ } else
+ len = resplen;
+ while (len != 0 &&
+ (n = read(s, (char *)cp, (int)len)) > 0) {
+ cp += n;
+ len -= n;
+ }
+ if (n <= 0) {
+ terrno = errno;
+#ifdef DEBUG
+ if (_res.options & RES_DEBUG)
+ perror("read failed");
+#endif
+ (void) close(s);
+ s = -1;
+ continue;
+ }
+ if (truncated) {
+ /*
+ * Flush rest of answer
+ * so connection stays in synch.
+ */
+ anhp->tc = 1;
+ len = resplen - anslen;
+ while (len != 0) {
+ n = (len > sizeof(junk) ?
+ sizeof(junk) : len);
+ if ((n = read(s, junk, n)) > 0)
+ len -= n;
+ else
+ break;
+ }
+ }
+ } else {
+ /*
+ * Use datagrams.
+ */
+ if (s < 0) {
+ s = socket(AF_INET, SOCK_DGRAM, 0);
+ if (s < 0) {
+ terrno = errno;
+#ifdef DEBUG
+ if (_res.options & RES_DEBUG)
+ perror("socket (dg) failed");
+#endif
+ continue;
+ }
+ }
+ /*
+ * I'm tired of answering this question, so:
+ * 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)) {
+ /*
+ * Don't use connect if we might
+ * still receive a response
+ * from another server.
+ */
+ if (connected == 0) {
+ if (connect(s,
+ (struct sockaddr *)
+ &_res.nsaddr_list[ns],
+ sizeof(struct sockaddr)) < 0) {
+#ifdef DEBUG
+ if (_res.options & RES_DEBUG)
+ perror("connect");
+#endif
+ continue;
+ }
+ connected = 1;
+ }
+ if (send(s, buf, buflen, 0) != buflen) {
+#ifdef DEBUG
+ if (_res.options & RES_DEBUG)
+ perror("send");
+#endif
+ continue;
+ }
+ } else {
+ /*
+ * Disconnect if we want to listen
+ * for responses from more than one server.
+ */
+ if (connected) {
+ (void) connect(s, &no_addr,
+ sizeof(no_addr));
+ connected = 0;
+ }
+ if (sendto(s, buf, buflen, 0,
+ (struct sockaddr *)&_res.nsaddr_list[ns],
+ sizeof(struct sockaddr)) != buflen) {
+#ifdef DEBUG
+ if (_res.options & RES_DEBUG)
+ perror("sendto");
+#endif
+ continue;
+ }
+ }
+
+ /*
+ * 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) {
+#ifdef DEBUG
+ if (_res.options & RES_DEBUG)
+ perror("select");
+#endif
+ continue;
+ }
+ if (n == 0) {
+ /*
+ * timeout
+ */
+#ifdef DEBUG
+ if (_res.options & RES_DEBUG)
+ printf(";; timeout\n");
+#endif
+ gotsomewhere = 1;
+ continue;
+ }
+ if ((resplen = recv(s, answer, anslen, 0)) <= 0) {
+#ifdef DEBUG
+ if (_res.options & RES_DEBUG)
+ perror("recvfrom");
+#endif
+ continue;
+ }
+ gotsomewhere = 1;
+ if (id != anhp->id) {
+ /*
+ * response from old query, ignore it
+ */
+#ifdef DEBUG
+ if ((_res.options & RES_DEBUG) ||
+ (_res.pfcode & RES_PRF_REPLY)) {
+ printf(";; old answer:\n");
+ __p_query(answer);
+ }
+#endif
+ goto wait;
+ }
+ if (anhp->rcode == SERVFAIL || anhp->rcode == NOTIMP ||
+ anhp->rcode == REFUSED) {
+#ifdef DEBUG
+ if (_res.options & RES_DEBUG) {
+ printf("server rejected query:\n");
+ __p_query(answer);
+ }
+#endif
+ badns |= (1<<ns);
+ continue;
+ }
+ if (!(_res.options & RES_IGNTC) && anhp->tc) {
+ /*
+ * get rest of answer;
+ * use TCP with same server.
+ */
+#ifdef DEBUG
+ if (_res.options & RES_DEBUG)
+ printf(";; truncated answer\n");
+#endif
+ (void) close(s);
+ s = -1;
+ v_circuit = 1;
+ goto usevc;
+ }
+ }
+#ifdef DEBUG
+ if (_res.options & RES_DEBUG)
+ printf(";; got answer:\n");
+ if ((_res.options & RES_DEBUG) ||
+ (_res.pfcode & RES_PRF_REPLY))
+ __p_query(answer);
+#endif
+ /*
+ * 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) == 0 || ns != 0)) ||
+ (_res.options & RES_STAYOPEN) == 0) {
+ (void) close(s);
+ s = -1;
+ }
+ return (resplen);
+ }
+ }
+ if (s >= 0) {
+ (void) close(s);
+ s = -1;
+ }
+ if (v_circuit == 0)
+ if (gotsomewhere == 0)
+ 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.
+ */
+_res_close()
+{
+ if (s != -1) {
+ (void) close(s);
+ s = -1;
+ }
+}
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