kernel - Reduce lwp_signotify() latency
[dragonfly.git] / usr.sbin / ypserv / yp_dnslookup.c
CommitLineData
984263bc
MD
1/*
2 * Copyright (c) 1995, 1996
3 * Bill Paul <wpaul@ctr.columbia.edu>. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
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.
19 *
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
30 * SUCH DAMAGE.
1de703da 31 *
ce0e08e2 32 * $FreeBSD: src/usr.sbin/ypserv/yp_dnslookup.c,v 1.27 2005/05/20 13:04:10 charnier Exp $
984263bc
MD
33 */
34
984263bc
MD
35/*
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.
39 *
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.
43 */
44
45#include <sys/param.h>
46#include <sys/socket.h>
47#include <sys/time.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>
53
54#include <ctype.h>
55#include <errno.h>
56#include <netdb.h>
57#include <stdio.h>
58#include <stdlib.h>
59#include <string.h>
60#include <resolv.h>
61#include <unistd.h>
62
63#include <rpcsvc/yp.h>
64#include "yp_extern.h"
65
7bb1f61f
CP
66static char *
67parse(struct hostent *hp)
984263bc
MD
68{
69 static char result[MAXHOSTNAMELEN * 2];
ce0e08e2
PA
70 int i;
71 size_t len;
72 char addr[46];
984263bc
MD
73
74 if (hp == NULL)
75 return(NULL);
76
ce0e08e2
PA
77 if (inet_ntop(hp->h_addrtype, hp->h_addr, addr, sizeof(addr)) == NULL)
78 return(NULL);
79
80 len = strlen(addr) + 1 + strlen(hp->h_name);
984263bc
MD
81 for (i = 0; hp->h_aliases[i]; i++)
82 len += strlen(hp->h_aliases[i]) + 1;
83 len++;
84
85 if (len > sizeof(result))
86 return(NULL);
87
88 bzero(result, sizeof(result));
ce0e08e2 89 snprintf(result, sizeof(result), "%s %s", addr, hp->h_name);
984263bc
MD
90 for (i = 0; hp->h_aliases[i]; i++) {
91 strcat(result, " ");
92 strcat(result, hp->h_aliases[i]);
93 }
94
95 return ((char *)&result);
96}
97
ce0e08e2 98#define MAXPACKET (64*1024)
984263bc
MD
99#define DEF_TTL 50
100
101#define BY_DNS_ID 1
102#define BY_RPC_XID 2
103
104extern struct hostent *__dns_getanswer(char *, int, char *, int);
105
ce0e08e2 106static TAILQ_HEAD(dns_qhead, circleq_dnsentry) qhead;
984263bc
MD
107
108struct circleq_dnsentry {
109 SVCXPRT *xprt;
110 unsigned long xid;
111 struct sockaddr_in client_addr;
112 unsigned long ypvers;
113 unsigned long id;
114 unsigned long ttl;
115 unsigned long type;
116 unsigned short prot_type;
117 char **domain;
118 char *name;
ce0e08e2
PA
119 int addrtype;
120 int addrlen;
121 uint32_t addr[4]; /* IPv4 or IPv6 */
122 TAILQ_ENTRY(circleq_dnsentry) links;
984263bc
MD
123};
124
125static int pending = 0;
126
7bb1f61f
CP
127int
128yp_init_resolver(void)
984263bc 129{
ce0e08e2 130 TAILQ_INIT(&qhead);
984263bc
MD
131 if (!(_res.options & RES_INIT) && res_init() == -1) {
132 yp_error("res_init failed");
133 return(1);
134 }
135 if ((resfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
136 yp_error("couldn't create socket");
137 return(1);
138 }
139 if (fcntl(resfd, F_SETFL, O_NONBLOCK) == -1) {
140 yp_error("couldn't make resolver socket non-blocking");
141 return(1);
142 }
143 return(0);
144}
145
7bb1f61f
CP
146static struct circleq_dnsentry *
147yp_malloc_dnsent(void)
984263bc 148{
7bb1f61f 149 struct circleq_dnsentry *q;
984263bc
MD
150
151 q = (struct circleq_dnsentry *)malloc(sizeof(struct circleq_dnsentry));
152
153 if (q == NULL) {
154 yp_error("failed to malloc() circleq dns entry");
155 return(NULL);
156 }
157
158 return(q);
159}
160
161/*
162 * Transmit a query.
163 */
7bb1f61f
CP
164static unsigned long
165yp_send_dns_query(char *name, int type)
984263bc
MD
166{
167 char buf[MAXPACKET];
168 int n;
169 HEADER *hptr;
170 int ns;
171 int rval;
172 unsigned long id;
173
174 bzero(buf, sizeof(buf));
175
176 n = res_mkquery(QUERY,name,C_IN,type,NULL,0,NULL,buf,sizeof(buf));
177
178 if (n <= 0) {
ce0e08e2 179 yp_error("res_mkquery failed for %s type %d", name, type);
984263bc
MD
180 return(0);
181 }
182
183 hptr = (HEADER *)&buf;
184 id = ntohs(hptr->id);
185
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));
190 if (rval == -1) {
191 yp_error("sendto failed");
192 return(0);
193 }
194 }
195
196 return(id);
197}
198
7bb1f61f
CP
199static struct circleq_dnsentry *
200yp_find_dnsqent(unsigned long id, int type)
984263bc 201{
7bb1f61f 202 struct circleq_dnsentry *q;
984263bc 203
ce0e08e2 204 TAILQ_FOREACH(q, &qhead, links) {
984263bc
MD
205 switch (type) {
206 case BY_RPC_XID:
207 if (id == q->xid)
208 return(q);
209 break;
210 case BY_DNS_ID:
211 default:
212 if (id == q->id)
213 return(q);
214 break;
215 }
216 }
217 return (NULL);
218}
219
7bb1f61f
CP
220static void
221yp_send_dns_reply(struct circleq_dnsentry *q, char *buf)
984263bc
MD
222{
223 ypresponse result_v1;
224 ypresp_val result_v2;
225 unsigned long xid;
226 struct sockaddr_in client_addr;
227 xdrproc_t xdrfunc;
228 char *result;
229
230 /*
231 * Set up correct reply struct and
232 * XDR filter depending on ypvers.
233 */
234 switch (q->ypvers) {
235 case YPVERS:
236 bzero((char *)&result_v2, sizeof(result_v2));
237
238 if (buf == NULL)
239 result_v2.stat = YP_NOKEY;
240 else {
241 result_v2.val.valdat_len = strlen(buf);
242 result_v2.val.valdat_val = buf;
243 result_v2.stat = YP_TRUE;
244 }
245 result = (char *)&result_v2;
246 xdrfunc = (xdrproc_t)xdr_ypresp_val;
247 break;
248 case YPOLDVERS:
249 /*
250 * The odds are we will _never_ execute this
251 * particular code, but we include it anyway
252 * for the sake of completeness.
253 */
254 bzero((char *)&result_v1, sizeof(result_v1));
255 result_v1.yp_resptype = YPRESP_VAL;
984263bc 256
ce0e08e2 257#define YPVAL ypresponse_u.yp_resp_valtype
984263bc
MD
258 if (buf == NULL)
259 result_v1.YPVAL.stat = YP_NOKEY;
260 else {
261 result_v1.YPVAL.val.valdat_len = strlen(buf);
262 result_v1.YPVAL.val.valdat_val = buf;
263 result_v1.YPVAL.stat = YP_TRUE;
264 }
265 result = (char *)&result_v1;
266 xdrfunc = (xdrproc_t)xdr_ypresponse;
267 break;
268 default:
269 yp_error("bad YP program version (%lu)!", q->ypvers);
270 return;
271 break;
272 }
273
274 if (debug)
275 yp_error("sending dns reply to %s (%lu)",
276 inet_ntoa(q->client_addr.sin_addr), q->id);
277 /*
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.
289 */
290 /*
291 * XXX Don't frob the transaction ID for TCP handles.
292 */
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;
297
298 if (!svc_sendreply(q->xprt, xdrfunc, result))
299 yp_error("svc_sendreply failed");
300
301 /*
302 * Now that we sent the reply,
303 * put the handle back the way it was.
304 */
305 if (q->prot_type == SOCK_DGRAM)
306 svcudp_set_xid(q->xprt, xid);
307 q->xprt->xp_raddr = client_addr;
308
309 return;
310}
311
312/*
313 * Decrement TTL on all queue entries, possibly nuking
314 * any that have been around too long without being serviced.
315 */
7bb1f61f
CP
316void
317yp_prune_dnsq(void)
984263bc 318{
7bb1f61f 319 struct circleq_dnsentry *q, *n;
984263bc 320
ce0e08e2
PA
321 q = TAILQ_FIRST(&qhead);
322 while (q != NULL) {
984263bc 323 q->ttl--;
ce0e08e2 324 n = TAILQ_NEXT(q, links);
984263bc 325 if (!q->ttl) {
ce0e08e2 326 TAILQ_REMOVE(&qhead, q, links);
984263bc
MD
327 free(q->name);
328 free(q);
329 pending--;
330 }
331 q = n;
332 }
333
334 if (pending < 0)
335 pending = 0;
336
337 return;
338}
339
340/*
341 * Data is pending on the DNS socket; check for valid replies
342 * to our queries and dispatch them to waiting clients.
343 */
7bb1f61f
CP
344void
345yp_run_dnsq(void)
984263bc 346{
7bb1f61f 347 struct circleq_dnsentry *q;
984263bc 348 char buf[sizeof(HEADER) + MAXPACKET];
984263bc 349 struct sockaddr_in sin;
ce0e08e2 350 socklen_t len;
984263bc 351 int rval;
984263bc
MD
352 HEADER *hptr;
353 struct hostent *hent;
354
355 if (debug)
356 yp_error("running dns queue");
357
358 bzero(buf, sizeof(buf));
359
360 len = sizeof(struct sockaddr_in);
361 rval = recvfrom(resfd, buf, sizeof(buf), 0,
362 (struct sockaddr *)&sin, &len);
363
364 if (rval == -1) {
365 yp_error("recvfrom failed: %s", strerror(errno));
366 return;
367 }
368
369 /*
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
374 * on the floor.
375 */
376 hptr = (HEADER *)&buf;
377 if (!pending ||
378 (q = yp_find_dnsqent(ntohs(hptr->id), BY_DNS_ID)) == NULL) {
379 /* ignore */
380 return;
381 }
382
383 if (debug)
384 yp_error("got dns reply from %s", inet_ntoa(sin.sin_addr));
385
386 hent = __dns_getanswer(buf, rval, q->name, q->type);
387
ce0e08e2 388 if (hent != NULL) {
984263bc 389 if (q->type == T_PTR) {
ce0e08e2
PA
390 hent->h_addr = (char *)q->addr;
391 hent->h_addrtype = q->addrtype;
392 hent->h_length = q->addrlen;
984263bc
MD
393 }
394 }
395
396 /* Got an answer ready for a client -- send it off. */
397 yp_send_dns_reply(q, parse(hent));
398 pending--;
ce0e08e2 399 TAILQ_REMOVE(&qhead, q, links);
984263bc
MD
400 free(q->name);
401 free(q);
402
403 /* Decrement TTLs on other entries while we're here. */
404 yp_prune_dnsq();
405
406 return;
407}
408
409/*
410 * Queue and transmit an asynchronous DNS hostname lookup.
411 */
7bb1f61f 412ypstat
ce0e08e2 413yp_async_lookup_name(struct svc_req *rqstp, char *name, int af)
984263bc 414{
7bb1f61f 415 struct circleq_dnsentry *q;
ce0e08e2
PA
416 socklen_t len;
417 int type;
984263bc
MD
418
419 /* Check for SOCK_DGRAM or SOCK_STREAM -- we need to know later */
ce0e08e2
PA
420 type = -1;
421 len = sizeof(type);
422 if (getsockopt(rqstp->rq_xprt->xp_fd, SOL_SOCKET,
984263bc
MD
423 SO_TYPE, &type, &len) == -1) {
424 yp_error("getsockopt failed: %s", strerror(errno));
425 return(YP_YPERR);
426 }
427
428 /* Avoid transmitting dupe requests. */
429 if (type == SOCK_DGRAM &&
430 yp_find_dnsqent(svcudp_get_xid(rqstp->rq_xprt),BY_RPC_XID) != NULL)
431 return(YP_TRUE);
432
433 if ((q = yp_malloc_dnsent()) == NULL)
434 return(YP_YPERR);
435
ce0e08e2 436 q->type = (af == AF_INET) ? T_A : T_AAAA;
984263bc
MD
437 q->ttl = DEF_TTL;
438 q->xprt = rqstp->rq_xprt;
439 q->ypvers = rqstp->rq_vers;
440 q->prot_type = type;
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);
446
447 if (q->id == 0) {
448 yp_error("DNS query failed");
449 free(q);
450 return(YP_YPERR);
451 }
452
453 q->name = strdup(name);
ce0e08e2 454 TAILQ_INSERT_HEAD(&qhead, q, links);
984263bc
MD
455 pending++;
456
457 if (debug)
51798e10 458 yp_error("queueing async DNS name lookup (%lu)", q->id);
984263bc
MD
459
460 yp_prune_dnsq();
461 return(YP_TRUE);
462}
463
464/*
465 * Queue and transmit an asynchronous DNS IP address lookup.
466 */
cac6c605 467ypstat
ce0e08e2 468yp_async_lookup_addr(struct svc_req *rqstp, char *addr, int af)
984263bc 469{
7bb1f61f 470 struct circleq_dnsentry *q;
ce0e08e2
PA
471 char buf[MAXHOSTNAMELEN], *qp;
472 uint32_t abuf[4]; /* IPv4 or IPv6 */
473 u_char *uaddr = (u_char *)abuf;
474 socklen_t len;
475 int type, n;
984263bc
MD
476
477 /* Check for SOCK_DGRAM or SOCK_STREAM -- we need to know later */
ce0e08e2
PA
478 type = -1;
479 len = sizeof(type);
480 if (getsockopt(rqstp->rq_xprt->xp_fd, SOL_SOCKET,
984263bc
MD
481 SO_TYPE, &type, &len) == -1) {
482 yp_error("getsockopt failed: %s", strerror(errno));
483 return(YP_YPERR);
484 }
485
486 /* Avoid transmitting dupe requests. */
487 if (type == SOCK_DGRAM &&
488 yp_find_dnsqent(svcudp_get_xid(rqstp->rq_xprt),BY_RPC_XID) != NULL)
489 return(YP_TRUE);
490
491 if ((q = yp_malloc_dnsent()) == NULL)
492 return(YP_YPERR);
493
ce0e08e2
PA
494 switch (af) {
495 case AF_INET:
496 if (inet_aton(addr, (struct in_addr *)uaddr) != 1)
497 return(YP_NOKEY);
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));
501 len = INADDRSZ;
502 break;
503 case AF_INET6:
504 if (inet_pton(af, addr, uaddr) != 1)
505 return(YP_NOKEY);
506 qp = buf;
507 for (n = IN6ADDRSZ - 1; n >= 0; n--) {
508 qp += (size_t)sprintf(qp, "%x.%x.", uaddr[n] & 0xf,
509 (uaddr[n] >> 4) & 0xf);
510 }
511 strlcat(buf, "ip6.arpa", sizeof(buf));
512 len = IN6ADDRSZ;
513 break;
514 default:
515 return(YP_YPERR);
516 }
984263bc
MD
517
518 if (debug)
519 yp_error("DNS address is: %s", buf);
520
521 q->type = T_PTR;
522 q->ttl = DEF_TTL;
523 q->xprt = rqstp->rq_xprt;
524 q->ypvers = rqstp->rq_vers;
525 q->domain = NULL;
526 q->prot_type = type;
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);
531
532 if (q->id == 0) {
533 yp_error("DNS query failed");
534 free(q);
535 return(YP_YPERR);
536 }
537
ce0e08e2
PA
538 memcpy(q->addr, uaddr, len);
539 q->addrlen = len;
540 q->addrtype = af;
984263bc 541 q->name = strdup(buf);
ce0e08e2 542 TAILQ_INSERT_HEAD(&qhead, q, links);
984263bc
MD
543 pending++;
544
545 if (debug)
51798e10 546 yp_error("queueing async DNS address lookup (%lu)", q->id);
984263bc
MD
547
548 yp_prune_dnsq();
549 return(YP_TRUE);
550}