xref: /csrg-svn/lib/libc/net/res_send.c (revision 24734)
118144Sralph /*
221388Sdist  * Copyright (c) 1985 Regents of the University of California.
321388Sdist  * All rights reserved.  The Berkeley software License Agreement
421388Sdist  * specifies the terms and conditions for redistribution.
518548Sralph  */
618548Sralph 
721388Sdist #ifndef lint
8*24734Sbloom static char sccsid[] = "@(#)res_send.c	5.5 (Berkeley) 09/14/85";
921388Sdist #endif not lint
1021388Sdist 
1118548Sralph /*
1218144Sralph  * Send query to name server and wait for reply.
1318144Sralph  */
1418144Sralph 
1518144Sralph #include <sys/types.h>
1618144Sralph #include <sys/time.h>
1718144Sralph #include <sys/socket.h>
1818144Sralph #include <netinet/in.h>
1918144Sralph #include <stdio.h>
2018144Sralph #include <errno.h>
2124083Skjd #include <arpa/nameser.h>
2224083Skjd #include <arpa/resolv.h>
2318144Sralph 
2418144Sralph extern int errno;
2518144Sralph 
2618531Sralph res_send(buf, buflen, answer, anslen)
2718144Sralph 	char *buf;
2818144Sralph 	int buflen;
2918144Sralph 	char *answer;
3018144Sralph 	int anslen;
3118144Sralph {
3218144Sralph 	register int n;
3318144Sralph 	int s, retry, v_circuit, resplen;
3418144Sralph 	u_short id, len;
3518144Sralph 	char *cp;
3618144Sralph 	int dsmask;
3718144Sralph 	struct timeval timeout;
3818144Sralph 	HEADER *hp = (HEADER *) buf;
3918144Sralph 	HEADER *anhp = (HEADER *) answer;
4018144Sralph 
41*24734Sbloom #ifdef DEBUG
4218144Sralph 	if (_res.options & RES_DEBUG) {
4318531Sralph 		printf("res_send()\n");
4418144Sralph 		p_query(buf);
4518144Sralph 	}
46*24734Sbloom #endif
4718531Sralph 	if (!(_res.options & RES_INIT))
48*24734Sbloom 		if (res_init() == -1) {
49*24734Sbloom 			return(-1);
50*24734Sbloom 		}
5118144Sralph 	s = -1;
5218144Sralph 	v_circuit = (_res.options & RES_USEVC) || buflen > PACKETSZ;
5318144Sralph 	id = hp->id;
5418144Sralph 	/*
5518144Sralph 	 * Send request, RETRY times, or until successful
5618144Sralph 	 */
5718144Sralph 	for (retry = _res.retry; --retry >= 0; ) {
5818144Sralph 		if (v_circuit) {
5918144Sralph 			/*
6018144Sralph 			 * Use virtual circuit.
6118144Sralph 			 */
6218144Sralph 			if (s < 0)
6318144Sralph 				s = socket(AF_INET, SOCK_STREAM, 0);
6418144Sralph 			if (connect(s, &_res.nsaddr, sizeof(_res.nsaddr)) < 0) {
65*24734Sbloom #ifdef DEBUG
6618144Sralph 				if (_res.options & RES_DEBUG)
6718144Sralph 					printf("connect failed %d\n", errno);
68*24734Sbloom #endif
6918144Sralph 				(void) close(s);
7018144Sralph 				s = -1;
7118144Sralph 				continue;
7218144Sralph 			}
7318144Sralph 			/*
7418144Sralph 			 * Send length & message
7518144Sralph 			 */
7618144Sralph 			len = htons(buflen);
7718144Sralph 			if (write(s, &len, sizeof(len)) != sizeof(len) ||
7818144Sralph 			    write(s, buf, buflen) != buflen) {
79*24734Sbloom #ifdef DEBUG
8018144Sralph 				if (_res.options & RES_DEBUG)
8118144Sralph 					printf("write failed %d\n", errno);
82*24734Sbloom #endif
8318144Sralph 				(void) close(s);
8418144Sralph 				s = -1;
8518144Sralph 				continue;
8618144Sralph 			}
8718144Sralph 			/*
8818144Sralph 			 * Receive length & response
8918144Sralph 			 */
9018144Sralph 			cp = answer;
9118144Sralph 			len = sizeof(short);
9218144Sralph 			while (len > 0 && (n = read(s, cp, len)) > 0) {
9318144Sralph 				cp += n;
9418144Sralph 				len -= n;
9518144Sralph 			}
9618144Sralph 			if (n <= 0) {
97*24734Sbloom #ifdef DEBUG
9818144Sralph 				if (_res.options & RES_DEBUG)
9918144Sralph 					printf("read failed %d\n", errno);
100*24734Sbloom #endif
10118144Sralph 				(void) close(s);
10218144Sralph 				s = -1;
10318144Sralph 				continue;
10418144Sralph 			}
10518144Sralph 			cp = answer;
10618144Sralph 			resplen = len = ntohs(*(short *)cp);
10718144Sralph 			while (len > 0 && (n = read(s, cp, len)) > 0) {
10818144Sralph 				cp += n;
10918144Sralph 				len -= n;
11018144Sralph 			}
11118144Sralph 			if (n <= 0) {
112*24734Sbloom #ifdef DEBUG
11318144Sralph 				if (_res.options & RES_DEBUG)
11418144Sralph 					printf("read failed %d\n", errno);
115*24734Sbloom #endif
11618144Sralph 				(void) close(s);
11718144Sralph 				s = -1;
11818144Sralph 				continue;
11918144Sralph 			}
12018144Sralph 		} else {
12118144Sralph 			/*
12218144Sralph 			 * Use datagrams.
12318144Sralph 			 */
12418144Sralph 			if (s < 0)
12518144Sralph 				s = socket(AF_INET, SOCK_DGRAM, 0);
12618144Sralph 			if (sendto(s, buf, buflen, 0, &_res.nsaddr,
12718144Sralph 			    sizeof(_res.nsaddr)) != buflen) {
128*24734Sbloom #ifdef DEBUG
12918144Sralph 				if (_res.options & RES_DEBUG)
13018144Sralph 					printf("sendto errno = %d\n", errno);
131*24734Sbloom #endif
13218144Sralph 			}
13318144Sralph 			/*
13418144Sralph 			 * Wait for reply
13518144Sralph 			 */
13618144Sralph 			timeout.tv_sec = _res.retrans;
13718144Sralph 			timeout.tv_usec = 0;
13818144Sralph 			dsmask = 1 << s;
13918144Sralph 			n = select(s+1, &dsmask, 0, 0, &timeout);
14018144Sralph 			if (n < 0) {
141*24734Sbloom #ifdef DEBUG
14218144Sralph 				if (_res.options & RES_DEBUG)
14318144Sralph 					printf("select errno = %d\n", errno);
144*24734Sbloom #endif
14518144Sralph 				continue;
14618144Sralph 			}
14718144Sralph 			if (n == 0) {
14818144Sralph 				/*
14918144Sralph 				 * timeout
15018144Sralph 				 */
151*24734Sbloom #ifdef DEBUG
15218144Sralph 				if (_res.options & RES_DEBUG)
15318144Sralph 					printf("timeout\n");
154*24734Sbloom #endif
15518144Sralph 				continue;
15618144Sralph 			}
15718144Sralph 			if ((resplen = recvfrom(s, answer, anslen,
15818144Sralph 			    0, 0, 0)) <= 0) {
159*24734Sbloom #ifdef DEBUG
16018144Sralph 				if (_res.options & RES_DEBUG)
16118144Sralph 					printf("recvfrom, errno=%d\n", errno);
162*24734Sbloom #endif
16318144Sralph 				continue;
16418144Sralph 			}
16518144Sralph 			if (id != anhp->id) {
16618144Sralph 				/*
16718144Sralph 				 * response from old query, ignore it
16818144Sralph 				 */
169*24734Sbloom #ifdef DEBUG
17018144Sralph 				if (_res.options & RES_DEBUG) {
17118144Sralph 					printf("old answer:\n");
17218144Sralph 					p_query(answer);
17318144Sralph 				}
174*24734Sbloom #endif
17518144Sralph 				continue;
17618144Sralph 			}
17718144Sralph 			if (!(_res.options & RES_IGNTC) && anhp->tc) {
17818144Sralph 				/*
17918144Sralph 				 * get rest of answer
18018144Sralph 				 */
181*24734Sbloom #ifdef DEBUG
18218144Sralph 				if (_res.options & RES_DEBUG)
18318144Sralph 					printf("truncated answer\n");
184*24734Sbloom #endif
18518144Sralph 				(void) close(s);
18618144Sralph 				s = -1;
18718144Sralph 				retry = _res.retry;
18818144Sralph 				v_circuit = 1;
18918144Sralph 				continue;
19018144Sralph 			}
19118144Sralph 		}
192*24734Sbloom #ifdef DEBUG
19318144Sralph 		if (_res.options & RES_DEBUG) {
19418144Sralph 			printf("got answer:\n");
19518144Sralph 			p_query(answer);
19618144Sralph 		}
197*24734Sbloom #endif
19823873Skjd 		(void) close(s);
19918144Sralph 		return (resplen);
20018144Sralph 	}
20123873Skjd 	(void) close(s);
20224032Skjd 	errno = ETIMEDOUT;
20318144Sralph 	return (-1);
20418144Sralph }
205