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
32 * $FreeBSD: src/usr.sbin/ypserv/yp_dnslookup.c,v 1.27 2005/05/20 13:04:10 charnier Exp $
36 * Do standard and reverse DNS lookups using the resolver library.
37 * Take care of all the dirty work here so the main program only has to
38 * pass us a pointer to an array of characters.
40 * We have to use direct resolver calls here otherwise the YP server
41 * could end up looping by calling itself over and over again until
42 * it disappeared up its own belly button.
45 #include <sys/param.h>
46 #include <sys/socket.h>
48 #include <sys/fcntl.h>
49 #include <sys/queue.h>
50 #include <netinet/in.h>
51 #include <arpa/inet.h>
52 #include <arpa/nameser.h>
63 #include <rpcsvc/yp.h>
64 #include "yp_extern.h"
67 parse(struct hostent *hp)
69 static char result[MAXHOSTNAMELEN * 2];
77 if (inet_ntop(hp->h_addrtype, hp->h_addr, addr, sizeof(addr)) == NULL)
80 len = strlen(addr) + 1 + strlen(hp->h_name);
81 for (i = 0; hp->h_aliases[i]; i++)
82 len += strlen(hp->h_aliases[i]) + 1;
85 if (len > sizeof(result))
88 bzero(result, sizeof(result));
89 snprintf(result, sizeof(result), "%s %s", addr, hp->h_name);
90 for (i = 0; hp->h_aliases[i]; i++) {
92 strcat(result, hp->h_aliases[i]);
95 return ((char *)&result);
98 #define MAXPACKET (64*1024)
104 extern struct hostent *__dns_getanswer(char *, int, char *, int);
106 static TAILQ_HEAD(dns_qhead, circleq_dnsentry) qhead;
108 struct circleq_dnsentry {
111 struct sockaddr_in client_addr;
112 unsigned long ypvers;
116 unsigned short prot_type;
121 uint32_t addr[4]; /* IPv4 or IPv6 */
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");
146 static struct circleq_dnsentry *
147 yp_malloc_dnsent(void)
149 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 for %s type %d", name, type);
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 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 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 struct circleq_dnsentry *q;
348 char buf[sizeof(HEADER) + MAXPACKET];
349 struct sockaddr_in sin;
353 struct hostent *hent;
356 yp_error("running dns queue");
358 bzero(buf, sizeof(buf));
360 len = sizeof(struct sockaddr_in);
361 rval = recvfrom(resfd, buf, sizeof(buf), 0,
362 (struct sockaddr *)&sin, &len);
365 yp_error("recvfrom failed: %s", strerror(errno));
370 * We may have data left in the socket that represents
371 * replies to earlier queries that we don't care about
372 * anymore. If there are no lookups pending or the packet
373 * ID doesn't match any of the queue IDs, just drop it
376 hptr = (HEADER *)&buf;
378 (q = yp_find_dnsqent(ntohs(hptr->id), BY_DNS_ID)) == NULL) {
384 yp_error("got dns reply from %s", inet_ntoa(sin.sin_addr));
386 hent = __dns_getanswer(buf, rval, q->name, q->type);
389 if (q->type == T_PTR) {
390 hent->h_addr = (char *)q->addr;
391 hent->h_addrtype = q->addrtype;
392 hent->h_length = q->addrlen;
396 /* Got an answer ready for a client -- send it off. */
397 yp_send_dns_reply(q, parse(hent));
399 TAILQ_REMOVE(&qhead, q, links);
403 /* Decrement TTLs on other entries while we're here. */
410 * Queue and transmit an asynchronous DNS hostname lookup.
413 yp_async_lookup_name(struct svc_req *rqstp, char *name, int af)
415 struct circleq_dnsentry *q;
419 /* Check for SOCK_DGRAM or SOCK_STREAM -- we need to know later */
422 if (getsockopt(rqstp->rq_xprt->xp_fd, SOL_SOCKET,
423 SO_TYPE, &type, &len) == -1) {
424 yp_error("getsockopt failed: %s", strerror(errno));
428 /* Avoid transmitting dupe requests. */
429 if (type == SOCK_DGRAM &&
430 yp_find_dnsqent(svcudp_get_xid(rqstp->rq_xprt),BY_RPC_XID) != NULL)
433 if ((q = yp_malloc_dnsent()) == NULL)
436 q->type = (af == AF_INET) ? T_A : T_AAAA;
438 q->xprt = rqstp->rq_xprt;
439 q->ypvers = rqstp->rq_vers;
441 if (q->prot_type == SOCK_DGRAM)
442 q->xid = svcudp_get_xid(q->xprt);
443 q->client_addr = q->xprt->xp_raddr;
444 q->domain = _res.dnsrch;
445 q->id = yp_send_dns_query(name, q->type);
448 yp_error("DNS query failed");
453 q->name = strdup(name);
454 TAILQ_INSERT_HEAD(&qhead, q, links);
458 yp_error("queueing async DNS name lookup (%lu)", q->id);
465 * Queue and transmit an asynchronous DNS IP address lookup.
468 yp_async_lookup_addr(struct svc_req *rqstp, char *addr, int af)
470 struct circleq_dnsentry *q;
471 char buf[MAXHOSTNAMELEN], *qp;
472 uint32_t abuf[4]; /* IPv4 or IPv6 */
473 u_char *uaddr = (u_char *)abuf;
477 /* Check for SOCK_DGRAM or SOCK_STREAM -- we need to know later */
480 if (getsockopt(rqstp->rq_xprt->xp_fd, SOL_SOCKET,
481 SO_TYPE, &type, &len) == -1) {
482 yp_error("getsockopt failed: %s", strerror(errno));
486 /* Avoid transmitting dupe requests. */
487 if (type == SOCK_DGRAM &&
488 yp_find_dnsqent(svcudp_get_xid(rqstp->rq_xprt),BY_RPC_XID) != NULL)
491 if ((q = yp_malloc_dnsent()) == NULL)
496 if (inet_aton(addr, (struct in_addr *)uaddr) != 1)
498 snprintf(buf, sizeof(buf), "%u.%u.%u.%u.in-addr.arpa",
499 (uaddr[3] & 0xff), (uaddr[2] & 0xff),
500 (uaddr[1] & 0xff), (uaddr[0] & 0xff));
504 if (inet_pton(af, addr, uaddr) != 1)
507 for (n = IN6ADDRSZ - 1; n >= 0; n--) {
508 qp += (size_t)sprintf(qp, "%x.%x.", uaddr[n] & 0xf,
509 (uaddr[n] >> 4) & 0xf);
511 strlcat(buf, "ip6.arpa", sizeof(buf));
519 yp_error("DNS address is: %s", buf);
523 q->xprt = rqstp->rq_xprt;
524 q->ypvers = rqstp->rq_vers;
527 if (q->prot_type == SOCK_DGRAM)
528 q->xid = svcudp_get_xid(q->xprt);
529 q->client_addr = q->xprt->xp_raddr;
530 q->id = yp_send_dns_query(buf, q->type);
533 yp_error("DNS query failed");
538 memcpy(q->addr, uaddr, len);
541 q->name = strdup(buf);
542 TAILQ_INSERT_HEAD(&qhead, q, links);
546 yp_error("queueing async DNS address lookup (%lu)", q->id);