2 * Copyright (c) 1995, 1996
3 * Bill Paul <wpaul@ctr.columbia.edu>. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by Bill Paul.
16 * 4. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY Bill Paul AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL Bill Paul OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 static const char rcsid[] =
39 * Do standard and reverse DNS lookups using the resolver library.
40 * Take care of all the dirty work here so the main program only has to
41 * pass us a pointer to an array of characters.
43 * We have to use direct resolver calls here otherwise the YP server
44 * could end up looping by calling itself over and over again until
45 * it disappeared up its own belly button.
48 #include <sys/param.h>
49 #include <sys/socket.h>
51 #include <sys/fcntl.h>
52 #include <sys/queue.h>
53 #include <netinet/in.h>
54 #include <arpa/inet.h>
55 #include <arpa/nameser.h>
66 #include <rpcsvc/yp.h>
67 #include "yp_extern.h"
70 parse(struct hostent *hp)
72 static char result[MAXHOSTNAMELEN * 2];
79 len = 16 + strlen(hp->h_name);
80 for (i = 0; hp->h_aliases[i]; i++)
81 len += strlen(hp->h_aliases[i]) + 1;
84 if (len > sizeof(result))
87 bzero(result, sizeof(result));
89 bcopy(hp->h_addr, &addr, sizeof(struct in_addr));
90 snprintf(result, sizeof(result), "%s %s", inet_ntoa(addr), hp->h_name);
92 for (i = 0; hp->h_aliases[i]; i++) {
94 strcat(result, hp->h_aliases[i]);
97 return ((char *)&result);
100 #define MAXPACKET 1024
106 extern struct hostent *__dns_getanswer(char *, int, char *, int);
108 static TAILQ_HEAD(dns_qhead, circleq_dnsentry) qhead;
110 struct circleq_dnsentry {
113 struct sockaddr_in client_addr;
114 unsigned long ypvers;
118 unsigned short prot_type;
122 TAILQ_ENTRY(circleq_dnsentry) links;
125 static int pending = 0;
128 yp_init_resolver(void)
131 if (!(_res.options & RES_INIT) && res_init() == -1) {
132 yp_error("res_init failed");
135 if ((resfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
136 yp_error("couldn't create socket");
139 if (fcntl(resfd, F_SETFL, O_NONBLOCK) == -1) {
140 yp_error("couldn't make resolver socket non-blocking");
147 circleq_dnsentry *yp_malloc_dnsent(void)
149 register struct circleq_dnsentry *q;
151 q = (struct circleq_dnsentry *)malloc(sizeof(struct circleq_dnsentry));
154 yp_error("failed to malloc() circleq dns entry");
165 yp_send_dns_query(char *name, int type)
174 bzero(buf, sizeof(buf));
176 n = res_mkquery(QUERY,name,C_IN,type,NULL,0,NULL,buf,sizeof(buf));
179 yp_error("res_mkquery failed");
183 hptr = (HEADER *)&buf;
184 id = ntohs(hptr->id);
186 for (ns = 0; ns < _res.nscount; ns++) {
187 rval = sendto(resfd, buf, n, 0,
188 (struct sockaddr *)&_res.nsaddr_list[ns],
189 sizeof(struct sockaddr));
191 yp_error("sendto failed");
199 static struct circleq_dnsentry *
200 yp_find_dnsqent(unsigned long id, int type)
202 register struct circleq_dnsentry *q;
204 TAILQ_FOREACH(q, &qhead, links) {
221 yp_send_dns_reply(struct circleq_dnsentry *q, char *buf)
223 ypresponse result_v1;
224 ypresp_val result_v2;
226 struct sockaddr_in client_addr;
231 * Set up correct reply struct and
232 * XDR filter depending on ypvers.
236 bzero((char *)&result_v2, sizeof(result_v2));
239 result_v2.stat = YP_NOKEY;
241 result_v2.val.valdat_len = strlen(buf);
242 result_v2.val.valdat_val = buf;
243 result_v2.stat = YP_TRUE;
245 result = (char *)&result_v2;
246 xdrfunc = (xdrproc_t)xdr_ypresp_val;
250 * The odds are we will _never_ execute this
251 * particular code, but we include it anyway
252 * for the sake of completeness.
254 bzero((char *)&result_v1, sizeof(result_v1));
255 result_v1.yp_resptype = YPRESP_VAL;
257 #define YPVAL ypresponse_u.yp_resp_valtype
259 result_v1.YPVAL.stat = YP_NOKEY;
261 result_v1.YPVAL.val.valdat_len = strlen(buf);
262 result_v1.YPVAL.val.valdat_val = buf;
263 result_v1.YPVAL.stat = YP_TRUE;
265 result = (char *)&result_v1;
266 xdrfunc = (xdrproc_t)xdr_ypresponse;
269 yp_error("bad YP program version (%lu)!", q->ypvers);
275 yp_error("sending dns reply to %s (%lu)",
276 inet_ntoa(q->client_addr.sin_addr), q->id);
278 * XXX This is disgusting. There's basically one transport
279 * handle for UDP, but we're holding off on replying to a
280 * client until we're ready, by which time we may have received
281 * several other queries from other clients with different
282 * transaction IDs. So to make the delayed response thing work,
283 * we have to save the transaction ID and client address of
284 * each request, then jam them into the transport handle when
285 * we're ready to send a reply. Then after we've send the reply,
286 * we put the old transaction ID and remote address back the
287 * way we found 'em. This is _INCREDIBLY_ non-portable; it's
288 * not even supported by the RPC library.
291 * XXX Don't frob the transaction ID for TCP handles.
293 if (q->prot_type == SOCK_DGRAM)
294 xid = svcudp_set_xid(q->xprt, q->xid);
295 client_addr = q->xprt->xp_raddr;
296 q->xprt->xp_raddr = q->client_addr;
298 if (!svc_sendreply(q->xprt, xdrfunc, result))
299 yp_error("svc_sendreply failed");
302 * Now that we sent the reply,
303 * put the handle back the way it was.
305 if (q->prot_type == SOCK_DGRAM)
306 svcudp_set_xid(q->xprt, xid);
307 q->xprt->xp_raddr = client_addr;
313 * Decrement TTL on all queue entries, possibly nuking
314 * any that have been around too long without being serviced.
319 register struct circleq_dnsentry *q, *n;
321 q = TAILQ_FIRST(&qhead);
324 n = TAILQ_NEXT(q, links);
326 TAILQ_REMOVE(&qhead, q, links);
341 * Data is pending on the DNS socket; check for valid replies
342 * to our queries and dispatch them to waiting clients.
347 register struct circleq_dnsentry *q;
348 char buf[sizeof(HEADER) + MAXPACKET];
349 char retrybuf[MAXHOSTNAMELEN];
350 struct sockaddr_in sin;
354 struct hostent *hent;
357 yp_error("running dns queue");
359 bzero(buf, sizeof(buf));
361 len = sizeof(struct sockaddr_in);
362 rval = recvfrom(resfd, buf, sizeof(buf), 0,
363 (struct sockaddr *)&sin, &len);
366 yp_error("recvfrom failed: %s", strerror(errno));
371 * We may have data left in the socket that represents
372 * replies to earlier queries that we don't care about
373 * anymore. If there are no lookups pending or the packet
374 * ID doesn't match any of the queue IDs, just drop it
377 hptr = (HEADER *)&buf;
379 (q = yp_find_dnsqent(ntohs(hptr->id), BY_DNS_ID)) == NULL) {
385 yp_error("got dns reply from %s", inet_ntoa(sin.sin_addr));
387 hent = __dns_getanswer(buf, rval, q->name, q->type);
390 * If the lookup failed, try appending one of the domains
391 * from resolv.conf. If we have no domains to test, the
395 if ((h_errno == TRY_AGAIN || h_errno == NO_RECOVERY)
396 && q->domain && *q->domain) {
397 snprintf(retrybuf, sizeof(retrybuf), "%s.%s",
398 q->name, *q->domain);
400 yp_error("retrying with: %s", retrybuf);
401 q->id = yp_send_dns_query(retrybuf, q->type);
407 if (q->type == T_PTR) {
408 hent->h_addr = (char *)&q->addr.s_addr;
409 hent->h_length = sizeof(struct in_addr);
413 /* Got an answer ready for a client -- send it off. */
414 yp_send_dns_reply(q, parse(hent));
416 TAILQ_REMOVE(&qhead, q, links);
420 /* Decrement TTLs on other entries while we're here. */
427 * Queue and transmit an asynchronous DNS hostname lookup.
430 yp_async_lookup_name(struct svc_req *rqstp, char *name)
432 register struct circleq_dnsentry *q;
435 /* Check for SOCK_DGRAM or SOCK_STREAM -- we need to know later */
436 type = -1; len = sizeof(type);
437 if (getsockopt(rqstp->rq_xprt->xp_fd, SOL_SOCKET,
438 SO_TYPE, &type, &len) == -1) {
439 yp_error("getsockopt failed: %s", strerror(errno));
443 /* Avoid transmitting dupe requests. */
444 if (type == SOCK_DGRAM &&
445 yp_find_dnsqent(svcudp_get_xid(rqstp->rq_xprt),BY_RPC_XID) != NULL)
448 if ((q = yp_malloc_dnsent()) == NULL)
453 q->xprt = rqstp->rq_xprt;
454 q->ypvers = rqstp->rq_vers;
456 if (q->prot_type == SOCK_DGRAM)
457 q->xid = svcudp_get_xid(q->xprt);
458 q->client_addr = q->xprt->xp_raddr;
459 q->domain = _res.dnsrch;
460 q->id = yp_send_dns_query(name, q->type);
463 yp_error("DNS query failed");
468 q->name = strdup(name);
469 TAILQ_INSERT_HEAD(&qhead, q, links);
473 yp_error("queueing async DNS name lookup (%d)", q->id);
480 * Queue and transmit an asynchronous DNS IP address lookup.
483 yp_async_lookup_addr(struct svc_req *rqstp, char *addr)
485 register struct circleq_dnsentry *q;
486 char buf[MAXHOSTNAMELEN];
490 /* Check for SOCK_DGRAM or SOCK_STREAM -- we need to know later */
491 type = -1; len = sizeof(type);
492 if (getsockopt(rqstp->rq_xprt->xp_fd, SOL_SOCKET,
493 SO_TYPE, &type, &len) == -1) {
494 yp_error("getsockopt failed: %s", strerror(errno));
498 /* Avoid transmitting dupe requests. */
499 if (type == SOCK_DGRAM &&
500 yp_find_dnsqent(svcudp_get_xid(rqstp->rq_xprt),BY_RPC_XID) != NULL)
503 if ((q = yp_malloc_dnsent()) == NULL)
506 if (sscanf(addr, "%d.%d.%d.%d", &a, &b, &c, &d) != 4)
509 snprintf(buf, sizeof(buf), "%d.%d.%d.%d.in-addr.arpa", d, c, b, a);
512 yp_error("DNS address is: %s", buf);
516 q->xprt = rqstp->rq_xprt;
517 q->ypvers = rqstp->rq_vers;
520 if (q->prot_type == SOCK_DGRAM)
521 q->xid = svcudp_get_xid(q->xprt);
522 q->client_addr = q->xprt->xp_raddr;
523 q->id = yp_send_dns_query(buf, q->type);
526 yp_error("DNS query failed");
531 inet_aton(addr, &q->addr);
532 q->name = strdup(buf);
533 TAILQ_INSERT_HEAD(&qhead, q, links);
537 yp_error("queueing async DNS address lookup (%d)", q->id);