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 $
33 * $DragonFly: src/usr.sbin/ypserv/yp_dnslookup.c,v 1.4 2005/11/24 22:23:02 swildner Exp $
37 * Do standard and reverse DNS lookups using the resolver library.
38 * Take care of all the dirty work here so the main program only has to
39 * pass us a pointer to an array of characters.
41 * We have to use direct resolver calls here otherwise the YP server
42 * could end up looping by calling itself over and over again until
43 * it disappeared up its own belly button.
46 #include <sys/param.h>
47 #include <sys/socket.h>
49 #include <sys/fcntl.h>
50 #include <sys/queue.h>
51 #include <netinet/in.h>
52 #include <arpa/inet.h>
53 #include <arpa/nameser.h>
64 #include <rpcsvc/yp.h>
65 #include "yp_extern.h"
68 parse(struct hostent *hp)
70 static char result[MAXHOSTNAMELEN * 2];
78 if (inet_ntop(hp->h_addrtype, hp->h_addr, addr, sizeof(addr)) == NULL)
81 len = strlen(addr) + 1 + strlen(hp->h_name);
82 for (i = 0; hp->h_aliases[i]; i++)
83 len += strlen(hp->h_aliases[i]) + 1;
86 if (len > sizeof(result))
89 bzero(result, sizeof(result));
90 snprintf(result, sizeof(result), "%s %s", addr, hp->h_name);
91 for (i = 0; hp->h_aliases[i]; i++) {
93 strcat(result, hp->h_aliases[i]);
96 return ((char *)&result);
99 #define MAXPACKET (64*1024)
105 extern struct hostent *__dns_getanswer(char *, int, char *, int);
107 static TAILQ_HEAD(dns_qhead, circleq_dnsentry) qhead;
109 struct circleq_dnsentry {
112 struct sockaddr_in client_addr;
113 unsigned long ypvers;
117 unsigned short prot_type;
122 uint32_t addr[4]; /* IPv4 or IPv6 */
123 TAILQ_ENTRY(circleq_dnsentry) links;
126 static int pending = 0;
129 yp_init_resolver(void)
132 if (!(_res.options & RES_INIT) && res_init() == -1) {
133 yp_error("res_init failed");
136 if ((resfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
137 yp_error("couldn't create socket");
140 if (fcntl(resfd, F_SETFL, O_NONBLOCK) == -1) {
141 yp_error("couldn't make resolver socket non-blocking");
147 static struct circleq_dnsentry *
148 yp_malloc_dnsent(void)
150 struct circleq_dnsentry *q;
152 q = (struct circleq_dnsentry *)malloc(sizeof(struct circleq_dnsentry));
155 yp_error("failed to malloc() circleq dns entry");
166 yp_send_dns_query(char *name, int type)
175 bzero(buf, sizeof(buf));
177 n = res_mkquery(QUERY,name,C_IN,type,NULL,0,NULL,buf,sizeof(buf));
180 yp_error("res_mkquery failed for %s type %d", name, type);
184 hptr = (HEADER *)&buf;
185 id = ntohs(hptr->id);
187 for (ns = 0; ns < _res.nscount; ns++) {
188 rval = sendto(resfd, buf, n, 0,
189 (struct sockaddr *)&_res.nsaddr_list[ns],
190 sizeof(struct sockaddr));
192 yp_error("sendto failed");
200 static struct circleq_dnsentry *
201 yp_find_dnsqent(unsigned long id, int type)
203 struct circleq_dnsentry *q;
205 TAILQ_FOREACH(q, &qhead, links) {
222 yp_send_dns_reply(struct circleq_dnsentry *q, char *buf)
224 ypresponse result_v1;
225 ypresp_val result_v2;
227 struct sockaddr_in client_addr;
232 * Set up correct reply struct and
233 * XDR filter depending on ypvers.
237 bzero((char *)&result_v2, sizeof(result_v2));
240 result_v2.stat = YP_NOKEY;
242 result_v2.val.valdat_len = strlen(buf);
243 result_v2.val.valdat_val = buf;
244 result_v2.stat = YP_TRUE;
246 result = (char *)&result_v2;
247 xdrfunc = (xdrproc_t)xdr_ypresp_val;
251 * The odds are we will _never_ execute this
252 * particular code, but we include it anyway
253 * for the sake of completeness.
255 bzero((char *)&result_v1, sizeof(result_v1));
256 result_v1.yp_resptype = YPRESP_VAL;
258 #define YPVAL ypresponse_u.yp_resp_valtype
260 result_v1.YPVAL.stat = YP_NOKEY;
262 result_v1.YPVAL.val.valdat_len = strlen(buf);
263 result_v1.YPVAL.val.valdat_val = buf;
264 result_v1.YPVAL.stat = YP_TRUE;
266 result = (char *)&result_v1;
267 xdrfunc = (xdrproc_t)xdr_ypresponse;
270 yp_error("bad YP program version (%lu)!", q->ypvers);
276 yp_error("sending dns reply to %s (%lu)",
277 inet_ntoa(q->client_addr.sin_addr), q->id);
279 * XXX This is disgusting. There's basically one transport
280 * handle for UDP, but we're holding off on replying to a
281 * client until we're ready, by which time we may have received
282 * several other queries from other clients with different
283 * transaction IDs. So to make the delayed response thing work,
284 * we have to save the transaction ID and client address of
285 * each request, then jam them into the transport handle when
286 * we're ready to send a reply. Then after we've send the reply,
287 * we put the old transaction ID and remote address back the
288 * way we found 'em. This is _INCREDIBLY_ non-portable; it's
289 * not even supported by the RPC library.
292 * XXX Don't frob the transaction ID for TCP handles.
294 if (q->prot_type == SOCK_DGRAM)
295 xid = svcudp_set_xid(q->xprt, q->xid);
296 client_addr = q->xprt->xp_raddr;
297 q->xprt->xp_raddr = q->client_addr;
299 if (!svc_sendreply(q->xprt, xdrfunc, result))
300 yp_error("svc_sendreply failed");
303 * Now that we sent the reply,
304 * put the handle back the way it was.
306 if (q->prot_type == SOCK_DGRAM)
307 svcudp_set_xid(q->xprt, xid);
308 q->xprt->xp_raddr = client_addr;
314 * Decrement TTL on all queue entries, possibly nuking
315 * any that have been around too long without being serviced.
320 struct circleq_dnsentry *q, *n;
322 q = TAILQ_FIRST(&qhead);
325 n = TAILQ_NEXT(q, links);
327 TAILQ_REMOVE(&qhead, q, links);
342 * Data is pending on the DNS socket; check for valid replies
343 * to our queries and dispatch them to waiting clients.
348 struct circleq_dnsentry *q;
349 char buf[sizeof(HEADER) + MAXPACKET];
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 (q->type == T_PTR) {
391 hent->h_addr = (char *)q->addr;
392 hent->h_addrtype = q->addrtype;
393 hent->h_length = q->addrlen;
397 /* Got an answer ready for a client -- send it off. */
398 yp_send_dns_reply(q, parse(hent));
400 TAILQ_REMOVE(&qhead, q, links);
404 /* Decrement TTLs on other entries while we're here. */
411 * Queue and transmit an asynchronous DNS hostname lookup.
414 yp_async_lookup_name(struct svc_req *rqstp, char *name, int af)
416 struct circleq_dnsentry *q;
420 /* Check for SOCK_DGRAM or SOCK_STREAM -- we need to know later */
423 if (getsockopt(rqstp->rq_xprt->xp_fd, SOL_SOCKET,
424 SO_TYPE, &type, &len) == -1) {
425 yp_error("getsockopt failed: %s", strerror(errno));
429 /* Avoid transmitting dupe requests. */
430 if (type == SOCK_DGRAM &&
431 yp_find_dnsqent(svcudp_get_xid(rqstp->rq_xprt),BY_RPC_XID) != NULL)
434 if ((q = yp_malloc_dnsent()) == NULL)
437 q->type = (af == AF_INET) ? T_A : T_AAAA;
439 q->xprt = rqstp->rq_xprt;
440 q->ypvers = rqstp->rq_vers;
442 if (q->prot_type == SOCK_DGRAM)
443 q->xid = svcudp_get_xid(q->xprt);
444 q->client_addr = q->xprt->xp_raddr;
445 q->domain = _res.dnsrch;
446 q->id = yp_send_dns_query(name, q->type);
449 yp_error("DNS query failed");
454 q->name = strdup(name);
455 TAILQ_INSERT_HEAD(&qhead, q, links);
459 yp_error("queueing async DNS name lookup (%d)", q->id);
466 * Queue and transmit an asynchronous DNS IP address lookup.
469 yp_async_lookup_addr(struct svc_req *rqstp, char *addr, int af)
471 struct circleq_dnsentry *q;
472 char buf[MAXHOSTNAMELEN], *qp;
473 uint32_t abuf[4]; /* IPv4 or IPv6 */
474 u_char *uaddr = (u_char *)abuf;
478 /* Check for SOCK_DGRAM or SOCK_STREAM -- we need to know later */
481 if (getsockopt(rqstp->rq_xprt->xp_fd, SOL_SOCKET,
482 SO_TYPE, &type, &len) == -1) {
483 yp_error("getsockopt failed: %s", strerror(errno));
487 /* Avoid transmitting dupe requests. */
488 if (type == SOCK_DGRAM &&
489 yp_find_dnsqent(svcudp_get_xid(rqstp->rq_xprt),BY_RPC_XID) != NULL)
492 if ((q = yp_malloc_dnsent()) == NULL)
497 if (inet_aton(addr, (struct in_addr *)uaddr) != 1)
499 snprintf(buf, sizeof(buf), "%u.%u.%u.%u.in-addr.arpa",
500 (uaddr[3] & 0xff), (uaddr[2] & 0xff),
501 (uaddr[1] & 0xff), (uaddr[0] & 0xff));
505 if (inet_pton(af, addr, uaddr) != 1)
508 for (n = IN6ADDRSZ - 1; n >= 0; n--) {
509 qp += (size_t)sprintf(qp, "%x.%x.", uaddr[n] & 0xf,
510 (uaddr[n] >> 4) & 0xf);
512 strlcat(buf, "ip6.arpa", sizeof(buf));
520 yp_error("DNS address is: %s", buf);
524 q->xprt = rqstp->rq_xprt;
525 q->ypvers = rqstp->rq_vers;
528 if (q->prot_type == SOCK_DGRAM)
529 q->xid = svcudp_get_xid(q->xprt);
530 q->client_addr = q->xprt->xp_raddr;
531 q->id = yp_send_dns_query(buf, q->type);
534 yp_error("DNS query failed");
539 memcpy(q->addr, uaddr, len);
542 q->name = strdup(buf);
543 TAILQ_INSERT_HEAD(&qhead, q, links);
547 yp_error("queueing async DNS address lookup (%d)", q->id);