ViewVC Help
View File | Revision Log | Show Annotations | View Changeset | Root Listing
root/svn/ircd-hybrid/branches/8.2.x/src/res.c
Revision: 3653
Committed: Mon May 26 15:42:10 2014 UTC (9 years, 10 months ago) by michael
Content type: text/x-csrc
File size: 23232 byte(s)
Log Message:
- res.c: removed unused definitions

File Contents

# Content
1 /*
2 * ircd-hybrid: an advanced, lightweight Internet Relay Chat Daemon (ircd)
3 *
4 * Copyright (c) 1997-2014 ircd-hybrid development team
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
19 * USA
20 */
21
22 /*! \file res.c
23 * \brief ircd resolver functions
24 * \version $Id$
25 */
26
27 /*
28 * A rewrite of Darren Reeds original res.c As there is nothing
29 * left of Darrens original code, this is now licensed by the hybrid group.
30 * (Well, some of the function names are the same, and bits of the structs..)
31 * You can use it where it is useful, free even. Buy us a beer and stuff.
32 *
33 * The authors takes no responsibility for any damage or loss
34 * of property which results from the use of this software.
35 *
36 * $Id$
37 *
38 * July 1999 - Rewrote a bunch of stuff here. Change hostent builder code,
39 * added callbacks and reference counting of returned hostents.
40 * --Bleep (Thomas Helvey <tomh@inxpress.net>)
41 *
42 * This was all needlessly complicated for irc. Simplified. No more hostent
43 * All we really care about is the IP -> hostname mappings. Thats all.
44 *
45 * Apr 28, 2003 --cryogen and Dianora
46 */
47
48 #include "stdinc.h"
49 #include "list.h"
50 #include "client.h"
51 #include "event.h"
52 #include "irc_string.h"
53 #include "ircd.h"
54 #include "numeric.h"
55 #include "rng_mt.h"
56 #include "fdlist.h"
57 #include "s_bsd.h"
58 #include "log.h"
59 #include "misc.h"
60 #include "send.h"
61 #include "memory.h"
62 #include "mempool.h"
63 #include "res.h"
64 #include "reslib.h"
65
66 #if (CHAR_BIT != 8)
67 #error this code needs to be able to address individual octets
68 #endif
69
70 static PF res_readreply;
71
72 #define MAXPACKET 1024 /* rfc sez 512 but we expand names so ... */
73 #define AR_TTL 600 /* TTL in seconds for dns cache entries */
74
75 /* RFC 1104/1105 wasn't very helpful about what these fields
76 * should be named, so for now, we'll just name them this way.
77 * we probably should look at what named calls them or something.
78 */
79 #define TYPE_SIZE (size_t)2
80 #define CLASS_SIZE (size_t)2
81 #define TTL_SIZE (size_t)4
82 #define RDLENGTH_SIZE (size_t)2
83 #define ANSWER_FIXED_SIZE (TYPE_SIZE + CLASS_SIZE + TTL_SIZE + RDLENGTH_SIZE)
84
85 typedef enum
86 {
87 REQ_IDLE, /* We're doing not much at all */
88 REQ_PTR, /* Looking up a PTR */
89 REQ_A, /* Looking up an A, possibly because AAAA failed */
90 #ifdef IPV6
91 REQ_AAAA, /* Looking up an AAAA */
92 #endif
93 REQ_CNAME /* We got a CNAME in response, we better get a real answer next */
94 } request_state;
95
96 struct reslist
97 {
98 dlink_node node;
99 int id;
100 int sent; /* number of requests sent */
101 request_state state; /* State the resolver machine is in */
102 time_t ttl;
103 char type;
104 char retries; /* retry counter */
105 unsigned int sends; /* number of sends (>1 means resent) */
106 char resend; /* send flag. 0 == dont resend */
107 time_t sentat;
108 time_t timeout;
109 struct irc_ssaddr addr;
110 char *name;
111 dns_callback_fnc callback;
112 void *callback_ctx;
113 };
114
115 static fde_t ResolverFileDescriptor;
116 static dlink_list request_list;
117 static mp_pool_t *dns_pool;
118
119 static void rem_request(struct reslist *);
120 static struct reslist *make_request(dns_callback_fnc, void *);
121 static void do_query_name(dns_callback_fnc, void *,
122 const char *, struct reslist *, int);
123 static void do_query_number(dns_callback_fnc, void *,
124 const struct irc_ssaddr *,
125 struct reslist *);
126 static void query_name(const char *, int, int, struct reslist *);
127 static int send_res_msg(const char *, int, unsigned int);
128 static void resend_query(struct reslist *);
129 static int proc_answer(struct reslist *, HEADER *, char *, char *);
130 static struct reslist *find_id(int);
131
132
133 /*
134 * int
135 * res_ourserver(inp)
136 * looks up "inp" in irc_nsaddr_list[]
137 * returns:
138 * 0 : not found
139 * >0 : found
140 * author:
141 * paul vixie, 29may94
142 * revised for ircd, cryogen(stu) may03
143 */
144 static int
145 res_ourserver(const struct irc_ssaddr *inp)
146 {
147 #ifdef IPV6
148 const struct sockaddr_in6 *v6;
149 const struct sockaddr_in6 *v6in = (const struct sockaddr_in6 *)inp;
150 #endif
151 const struct sockaddr_in *v4;
152 const struct sockaddr_in *v4in = (const struct sockaddr_in *)inp;
153
154 for (unsigned int i = 0; i < irc_nscount; ++i)
155 {
156 const struct irc_ssaddr *srv = &irc_nsaddr_list[i];
157 #ifdef IPV6
158 v6 = (const struct sockaddr_in6 *)srv;
159 #endif
160 v4 = (const struct sockaddr_in *)srv;
161
162 /* could probably just memcmp(srv, inp, srv.ss_len) here
163 * but we'll air on the side of caution - stu
164 *
165 */
166 switch (srv->ss.ss_family)
167 {
168 #ifdef IPV6
169 case AF_INET6:
170 if (srv->ss.ss_family == inp->ss.ss_family)
171 if (v6->sin6_port == v6in->sin6_port)
172 if (!memcmp(&v6->sin6_addr.s6_addr, &v6in->sin6_addr.s6_addr,
173 sizeof(struct in6_addr)))
174 return 1;
175 break;
176 #endif
177 case AF_INET:
178 if (srv->ss.ss_family == inp->ss.ss_family)
179 if (v4->sin_port == v4in->sin_port)
180 if (v4->sin_addr.s_addr == v4in->sin_addr.s_addr)
181 return 1;
182 break;
183 default:
184 break;
185 }
186 }
187
188 return 0;
189 }
190
191 /*
192 * timeout_query_list - Remove queries from the list which have been
193 * there too long without being resolved.
194 */
195 static time_t
196 timeout_query_list(time_t now)
197 {
198 dlink_node *ptr = NULL, *ptr_next = NULL;
199 struct reslist *request;
200 time_t next_time = 0;
201 time_t timeout = 0;
202
203 DLINK_FOREACH_SAFE(ptr, ptr_next, request_list.head)
204 {
205 request = ptr->data;
206 timeout = request->sentat + request->timeout;
207
208 if (now >= timeout)
209 {
210 if (--request->retries <= 0)
211 {
212 (*request->callback)(request->callback_ctx, NULL, NULL);
213 rem_request(request);
214 continue;
215 }
216 else
217 {
218 request->sentat = now;
219 request->timeout += request->timeout;
220 resend_query(request);
221 }
222 }
223
224 if ((next_time == 0) || timeout < next_time)
225 next_time = timeout;
226 }
227
228 return (next_time > now) ? next_time : (now + AR_TTL);
229 }
230
231 /*
232 * timeout_resolver - check request list
233 */
234 static void
235 timeout_resolver(void *notused)
236 {
237 timeout_query_list(CurrentTime);
238 }
239
240 /*
241 * start_resolver - do everything we need to read the resolv.conf file
242 * and initialize the resolver file descriptor if needed
243 */
244 static void
245 start_resolver(void)
246 {
247 irc_res_init();
248
249 if (!ResolverFileDescriptor.flags.open)
250 {
251 if (comm_open(&ResolverFileDescriptor, irc_nsaddr_list[0].ss.ss_family,
252 SOCK_DGRAM, 0, "Resolver socket") == -1)
253 return;
254
255 /* At the moment, the resolver FD data is global .. */
256 comm_setselect(&ResolverFileDescriptor, COMM_SELECT_READ, res_readreply, NULL, 0);
257 eventAdd("timeout_resolver", timeout_resolver, NULL, 1);
258 }
259 }
260
261 /*
262 * init_resolver - initialize resolver and resolver library
263 */
264 void
265 init_resolver(void)
266 {
267 dns_pool = mp_pool_new(sizeof(struct reslist), MP_CHUNK_SIZE_DNS);
268 memset(&ResolverFileDescriptor, 0, sizeof(fde_t));
269 start_resolver();
270 }
271
272 /*
273 * restart_resolver - reread resolv.conf, reopen socket
274 */
275 void
276 restart_resolver(void)
277 {
278 fd_close(&ResolverFileDescriptor);
279 eventDelete(timeout_resolver, NULL);
280 start_resolver();
281 }
282
283 /*
284 * rem_request - remove a request from the list.
285 * This must also free any memory that has been allocated for
286 * temporary storage of DNS results.
287 */
288 static void
289 rem_request(struct reslist *request)
290 {
291 dlinkDelete(&request->node, &request_list);
292
293 MyFree(request->name);
294 mp_pool_release(request);
295 }
296
297 /*
298 * make_request - Create a DNS request record for the server.
299 */
300 static struct reslist *
301 make_request(dns_callback_fnc callback, void *ctx)
302 {
303 struct reslist *request = mp_pool_get(dns_pool);
304
305 memset(request, 0, sizeof(*request));
306 request->sentat = CurrentTime;
307 request->retries = 2;
308 request->resend = 1;
309 request->timeout = 4; /* Start at 4 and exponential inc. */
310 request->state = REQ_IDLE;
311 request->callback = callback;
312 request->callback_ctx = ctx;
313
314 dlinkAdd(request, &request->node, &request_list);
315 return request;
316 }
317
318 /*
319 * delete_resolver_queries - cleanup outstanding queries
320 * for which there no longer exist clients or conf lines.
321 */
322 void
323 delete_resolver_queries(const void *vptr)
324 {
325 dlink_node *ptr = NULL, *ptr_next = NULL;
326
327 DLINK_FOREACH_SAFE(ptr, ptr_next, request_list.head)
328 {
329 struct reslist *request = ptr->data;
330
331 if (request->callback_ctx == vptr)
332 rem_request(request);
333 }
334 }
335
336 /*
337 * send_res_msg - sends msg to all nameservers found in the "_res" structure.
338 * This should reflect /etc/resolv.conf. We will get responses
339 * which arent needed but is easier than checking to see if nameserver
340 * isnt present. Returns number of messages successfully sent to
341 * nameservers or -1 if no successful sends.
342 */
343 static int
344 send_res_msg(const char *msg, int len, unsigned int rcount)
345 {
346 int sent = 0;
347 unsigned int max_queries = IRCD_MIN(irc_nscount, rcount);
348
349 /* RES_PRIMARY option is not implemented
350 * if (res.options & RES_PRIMARY || 0 == max_queries)
351 */
352 if (max_queries == 0)
353 max_queries = 1;
354
355 for (unsigned int i = 0; i < max_queries; ++i)
356 {
357 if (sendto(ResolverFileDescriptor.fd, msg, len, 0,
358 (struct sockaddr*)&(irc_nsaddr_list[i]),
359 irc_nsaddr_list[i].ss_len) == len)
360 ++sent;
361 }
362
363 return sent;
364 }
365
366 /*
367 * find_id - find a dns request id (id is determined by dn_mkquery)
368 */
369 static struct reslist *
370 find_id(int id)
371 {
372 dlink_node *ptr = NULL;
373
374 DLINK_FOREACH(ptr, request_list.head)
375 {
376 struct reslist *request = ptr->data;
377
378 if (request->id == id)
379 return request;
380 }
381
382 return NULL;
383 }
384
385 /*
386 * gethost_byname_type - get host address from name
387 *
388 */
389 void
390 gethost_byname_type(dns_callback_fnc callback, void *ctx, const char *name, int type)
391 {
392 assert(name);
393 do_query_name(callback, ctx, name, NULL, type);
394 }
395
396 /*
397 * gethost_byname - wrapper for _type - send T_AAAA first if IPV6 supported
398 */
399 void
400 gethost_byname(dns_callback_fnc callback, void *ctx, const char *name)
401 {
402 #ifdef IPV6
403 gethost_byname_type(callback, ctx, name, T_AAAA);
404 #else
405 gethost_byname_type(callback, ctx, name, T_A);
406 #endif
407 }
408
409 /*
410 * gethost_byaddr - get host name from address
411 */
412 void
413 gethost_byaddr(dns_callback_fnc callback, void *ctx, const struct irc_ssaddr *addr)
414 {
415 do_query_number(callback, ctx, addr, NULL);
416 }
417
418 /*
419 * do_query_name - nameserver lookup name
420 */
421 static void
422 do_query_name(dns_callback_fnc callback, void *ctx, const char *name,
423 struct reslist *request, int type)
424 {
425 char host_name[HOSTLEN + 1];
426
427 strlcpy(host_name, name, sizeof(host_name));
428
429 if (request == NULL)
430 {
431 request = make_request(callback, ctx);
432 request->name = MyCalloc(strlen(host_name) + 1);
433 request->type = type;
434 strcpy(request->name, host_name);
435 #ifdef IPV6
436 if (type != T_A)
437 request->state = REQ_AAAA;
438 else
439 #endif
440 request->state = REQ_A;
441 }
442
443 request->type = type;
444 query_name(host_name, C_IN, type, request);
445 }
446
447 /*
448 * do_query_number - Use this to do reverse IP# lookups.
449 */
450 static void
451 do_query_number(dns_callback_fnc callback, void *ctx,
452 const struct irc_ssaddr *addr,
453 struct reslist *request)
454 {
455 char ipbuf[128] = "";
456
457 if (addr->ss.ss_family == AF_INET)
458 {
459 const struct sockaddr_in *v4 = (const struct sockaddr_in *)addr;
460 const unsigned char *cp = (const unsigned char *)&v4->sin_addr.s_addr;
461
462 snprintf(ipbuf, sizeof(ipbuf), "%u.%u.%u.%u.in-addr.arpa.",
463 (unsigned int)(cp[3]), (unsigned int)(cp[2]),
464 (unsigned int)(cp[1]), (unsigned int)(cp[0]));
465 }
466 #ifdef IPV6
467 else if (addr->ss.ss_family == AF_INET6)
468 {
469 const struct sockaddr_in6 *v6 = (const struct sockaddr_in6 *)addr;
470 const unsigned char *cp = (const unsigned char *)&v6->sin6_addr.s6_addr;
471
472 snprintf(ipbuf, sizeof(ipbuf),
473 "%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x."
474 "%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.ip6.arpa.",
475 (unsigned int)(cp[15] & 0xf), (unsigned int)(cp[15] >> 4),
476 (unsigned int)(cp[14] & 0xf), (unsigned int)(cp[14] >> 4),
477 (unsigned int)(cp[13] & 0xf), (unsigned int)(cp[13] >> 4),
478 (unsigned int)(cp[12] & 0xf), (unsigned int)(cp[12] >> 4),
479 (unsigned int)(cp[11] & 0xf), (unsigned int)(cp[11] >> 4),
480 (unsigned int)(cp[10] & 0xf), (unsigned int)(cp[10] >> 4),
481 (unsigned int)(cp[9] & 0xf), (unsigned int)(cp[9] >> 4),
482 (unsigned int)(cp[8] & 0xf), (unsigned int)(cp[8] >> 4),
483 (unsigned int)(cp[7] & 0xf), (unsigned int)(cp[7] >> 4),
484 (unsigned int)(cp[6] & 0xf), (unsigned int)(cp[6] >> 4),
485 (unsigned int)(cp[5] & 0xf), (unsigned int)(cp[5] >> 4),
486 (unsigned int)(cp[4] & 0xf), (unsigned int)(cp[4] >> 4),
487 (unsigned int)(cp[3] & 0xf), (unsigned int)(cp[3] >> 4),
488 (unsigned int)(cp[2] & 0xf), (unsigned int)(cp[2] >> 4),
489 (unsigned int)(cp[1] & 0xf), (unsigned int)(cp[1] >> 4),
490 (unsigned int)(cp[0] & 0xf), (unsigned int)(cp[0] >> 4));
491 }
492 #endif
493 if (request == NULL)
494 {
495 request = make_request(callback, ctx);
496 request->type = T_PTR;
497 memcpy(&request->addr, addr, sizeof(struct irc_ssaddr));
498 request->name = MyCalloc(HOSTLEN + 1);
499 }
500
501 query_name(ipbuf, C_IN, T_PTR, request);
502 }
503
504 /*
505 * query_name - generate a query based on class, type and name.
506 */
507 static void
508 query_name(const char *name, int query_class, int type,
509 struct reslist *request)
510 {
511 char buf[MAXPACKET];
512 int request_len = 0;
513
514 memset(buf, 0, sizeof(buf));
515
516 if ((request_len = irc_res_mkquery(name, query_class, type,
517 (unsigned char *)buf, sizeof(buf))) > 0)
518 {
519 HEADER *header = (HEADER *)buf;
520
521 /*
522 * generate an unique id
523 * NOTE: we don't have to worry about converting this to and from
524 * network byte order, the nameserver does not interpret this value
525 * and returns it unchanged
526 */
527 do
528 header->id = (header->id + genrand_int32()) & 0xffff;
529 while (find_id(header->id));
530
531 request->id = header->id;
532 ++request->sends;
533
534 request->sent += send_res_msg(buf, request_len, request->sends);
535 }
536 }
537
538 static void
539 resend_query(struct reslist *request)
540 {
541 if (request->resend == 0)
542 return;
543
544 switch (request->type)
545 {
546 case T_PTR:
547 do_query_number(NULL, NULL, &request->addr, request);
548 break;
549 case T_A:
550 do_query_name(NULL, NULL, request->name, request, request->type);
551 break;
552 #ifdef IPV6
553 case T_AAAA:
554 /* didnt work, try A */
555 if (request->state == REQ_AAAA)
556 do_query_name(NULL, NULL, request->name, request, T_A);
557 #endif
558 default:
559 break;
560 }
561 }
562
563 /*
564 * proc_answer - process name server reply
565 */
566 static int
567 proc_answer(struct reslist *request, HEADER *header, char *buf, char *eob)
568 {
569 char hostbuf[HOSTLEN + 100]; /* working buffer */
570 unsigned char *current; /* current position in buf */
571 int query_class; /* answer class */
572 int type; /* answer type */
573 int n; /* temp count */
574 int rd_length;
575 struct sockaddr_in *v4; /* conversion */
576 #ifdef IPV6
577 struct sockaddr_in6 *v6;
578 #endif
579 current = (unsigned char *)buf + sizeof(HEADER);
580
581 for (; header->qdcount > 0; --header->qdcount)
582 {
583 if ((n = irc_dn_skipname(current, (unsigned char *)eob)) < 0)
584 break;
585
586 current += (size_t)n + QFIXEDSZ;
587 }
588
589 /*
590 * process each answer sent to us blech.
591 */
592 while (header->ancount > 0 && (char *)current < eob)
593 {
594 header->ancount--;
595
596 n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob, current,
597 hostbuf, sizeof(hostbuf));
598
599 if (n < 0 /* Broken message */ || n == 0 /* No more answers left */)
600 return 0;
601
602 hostbuf[HOSTLEN] = '\0';
603
604 /* With Address arithmetic you have to be very anal
605 * this code was not working on alpha due to that
606 * (spotted by rodder/jailbird/dianora)
607 */
608 current += (size_t)n;
609
610 if (!(((char *)current + ANSWER_FIXED_SIZE) < eob))
611 break;
612
613 type = irc_ns_get16(current);
614 current += TYPE_SIZE;
615
616 query_class = irc_ns_get16(current);
617 current += CLASS_SIZE;
618
619 request->ttl = irc_ns_get32(current);
620 current += TTL_SIZE;
621
622 rd_length = irc_ns_get16(current);
623 current += RDLENGTH_SIZE;
624
625 /*
626 * Wait to set request->type until we verify this structure
627 */
628 switch (type)
629 {
630 case T_A:
631 if (request->type != T_A)
632 return 0;
633
634 /*
635 * Check for invalid rd_length or too many addresses
636 */
637 if (rd_length != sizeof(struct in_addr))
638 return 0;
639
640 v4 = (struct sockaddr_in *)&request->addr;
641 request->addr.ss_len = sizeof(struct sockaddr_in);
642 v4->sin_family = AF_INET;
643 memcpy(&v4->sin_addr, current, sizeof(struct in_addr));
644 return 1;
645 break;
646 #ifdef IPV6
647 case T_AAAA:
648 if (request->type != T_AAAA)
649 return 0;
650
651 if (rd_length != sizeof(struct in6_addr))
652 return 0;
653
654 request->addr.ss_len = sizeof(struct sockaddr_in6);
655 v6 = (struct sockaddr_in6 *)&request->addr;
656 v6->sin6_family = AF_INET6;
657 memcpy(&v6->sin6_addr, current, sizeof(struct in6_addr));
658 return 1;
659 break;
660 #endif
661 case T_PTR:
662 if (request->type != T_PTR)
663 return 0;
664
665 n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob,
666 current, hostbuf, sizeof(hostbuf));
667 if (n < 0 /* Broken message */ || n == 0 /* No more answers left */)
668 return 0;
669
670 strlcpy(request->name, hostbuf, HOSTLEN + 1);
671 return 1;
672 break;
673 case T_CNAME: /* first check we already havent started looking
674 into a cname */
675 if (request->type != T_PTR)
676 return 0;
677
678 if (request->state == REQ_CNAME)
679 {
680 n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob,
681 current, hostbuf, sizeof(hostbuf));
682
683 if (n < 0)
684 return 0;
685 return 1;
686 }
687
688 request->state = REQ_CNAME;
689 current += rd_length;
690 break;
691
692 default:
693 /* XXX I'd rather just throw away the entire bogus thing
694 * but its possible its just a broken nameserver with still
695 * valid answers. But lets do some rudimentary logging for now...
696 */
697 ilog(LOG_TYPE_IRCD, "irc_res.c bogus type %d", type);
698 break;
699 }
700 }
701
702 return 1;
703 }
704
705 /*
706 * res_readreply - read a dns reply from the nameserver and process it.
707 */
708 static void
709 res_readreply(fde_t *fd, void *data)
710 {
711 char buf[sizeof(HEADER) + MAXPACKET]
712 /* Sparc and alpha need 16bit-alignment for accessing header->id
713 * (which is uint16_t). Because of the header = (HEADER*) buf;
714 * lateron, this is neeeded. --FaUl
715 */
716 #if defined(__sparc__) || defined(__alpha__)
717 __attribute__((aligned (16)))
718 #endif
719 ;
720 HEADER *header;
721 struct reslist *request = NULL;
722 int rc;
723 socklen_t len = sizeof(struct irc_ssaddr);
724 struct irc_ssaddr lsin;
725
726 rc = recvfrom(fd->fd, buf, sizeof(buf), 0, (struct sockaddr *)&lsin, &len);
727
728 /* Re-schedule a read *after* recvfrom, or we'll be registering
729 * interest where it'll instantly be ready for read :-) -- adrian
730 */
731 comm_setselect(fd, COMM_SELECT_READ, res_readreply, NULL, 0);
732
733 /* Better to cast the sizeof instead of rc */
734 if (rc <= (int)(sizeof(HEADER)))
735 return;
736
737 /*
738 * Convert DNS reply reader from Network byte order to CPU byte order.
739 */
740 header = (HEADER *)buf;
741 header->ancount = ntohs(header->ancount);
742 header->qdcount = ntohs(header->qdcount);
743 header->nscount = ntohs(header->nscount);
744 header->arcount = ntohs(header->arcount);
745
746 /*
747 * Check against possibly fake replies
748 */
749 if (!res_ourserver(&lsin))
750 return;
751
752 /*
753 * Response for an id which we have already received an answer for
754 * just ignore this response.
755 */
756 if (!(request = find_id(header->id)))
757 return;
758
759 if ((header->rcode != NO_ERRORS) || (header->ancount == 0))
760 {
761 if (header->rcode == SERVFAIL || header->rcode == NXDOMAIN)
762 {
763 /*
764 * If a bad error was returned, stop here and don't
765 * send any more (no retries granted).
766 */
767 (*request->callback)(request->callback_ctx, NULL, NULL);
768 rem_request(request);
769 }
770 #ifdef IPV6
771 else
772 {
773 /*
774 * If we havent already tried this, and we're looking up AAAA, try A
775 * now
776 */
777 if (request->state == REQ_AAAA && request->type == T_AAAA)
778 {
779 request->timeout += 4;
780 resend_query(request);
781 }
782 }
783 #endif
784
785 return;
786 }
787
788 /*
789 * If this fails there was an error decoding the received packet,
790 * try it again and hope it works the next time.
791 */
792 if (proc_answer(request, header, buf, buf + rc))
793 {
794 if (request->type == T_PTR)
795 {
796 if (request->name == NULL)
797 {
798 /*
799 * Got a PTR response with no name, something bogus is happening
800 * don't bother trying again, the client address doesn't resolve
801 */
802 (*request->callback)(request->callback_ctx, NULL, NULL);
803 rem_request(request);
804 return;
805 }
806
807 /*
808 * Lookup the 'authoritative' name that we were given for the ip#.
809 */
810 #ifdef IPV6
811 if (request->addr.ss.ss_family == AF_INET6)
812 gethost_byname_type(request->callback, request->callback_ctx, request->name, T_AAAA);
813 else
814 #endif
815 gethost_byname_type(request->callback, request->callback_ctx, request->name, T_A);
816 rem_request(request);
817 }
818 else
819 {
820 /*
821 * Got a name and address response, client resolved
822 */
823 (*request->callback)(request->callback_ctx, &request->addr, request->name);
824 rem_request(request);
825 }
826 }
827 else if (!request->sent)
828 {
829 /* XXX - we got a response for a query we didn't send with a valid id?
830 * this should never happen, bail here and leave the client unresolved
831 */
832 assert(0);
833
834 /* XXX don't leak it */
835 rem_request(request);
836 }
837 }
838
839 void
840 report_dns_servers(struct Client *source_p)
841 {
842 char ipaddr[HOSTIPLEN + 1] = "";
843
844 for (unsigned int i = 0; i < irc_nscount; ++i)
845 {
846 getnameinfo((struct sockaddr *)&(irc_nsaddr_list[i]),
847 irc_nsaddr_list[i].ss_len, ipaddr,
848 sizeof(ipaddr), NULL, 0, NI_NUMERICHOST);
849 sendto_one_numeric(source_p, &me, RPL_STATSALINE, ipaddr);
850 }
851 }

Properties

Name Value
svn:eol-style native
svn:keywords Id Revision