/[svn]/ircd-hybrid-7.2/src/irc_res.c
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Contents of /ircd-hybrid-7.2/src/irc_res.c

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Revision 1011 - (show annotations)
Fri Sep 18 10:14:09 2009 UTC (10 years, 2 months ago) by michael
File MIME type: text/x-chdr
File size: 23057 byte(s)
- move list manipulation routines from tools.c to list.c
- mem_frob() goes to memory.c
- sort out redundant/unneeded header includes

1 /*
2 * A rewrite of Darren Reeds original res.c As there is nothing
3 * left of Darrens original code, this is now licensed by the hybrid group.
4 * (Well, some of the function names are the same, and bits of the structs..)
5 * You can use it where it is useful, free even. Buy us a beer and stuff.
6 *
7 * The authors takes no responsibility for any damage or loss
8 * of property which results from the use of this software.
9 *
10 * $Id$
11 *
12 * July 1999 - Rewrote a bunch of stuff here. Change hostent builder code,
13 * added callbacks and reference counting of returned hostents.
14 * --Bleep (Thomas Helvey <tomh@inxpress.net>)
15 *
16 * This was all needlessly complicated for irc. Simplified. No more hostent
17 * All we really care about is the IP -> hostname mappings. Thats all.
18 *
19 * Apr 28, 2003 --cryogen and Dianora
20 */
21
22 #include "stdinc.h"
23 #include "list.h"
24 #include "balloc.h"
25 #include "client.h"
26 #include "event.h"
27 #include "irc_string.h"
28 #include "sprintf_irc.h"
29 #include "ircd.h"
30 #include "numeric.h"
31 #include "rng_mt.h"
32 #include "fdlist.h"
33 #include "fileio.h" /* for fbopen / fbclose / fbputs */
34 #include "s_bsd.h"
35 #include "s_log.h"
36 #include "send.h"
37 #include "memory.h"
38 #include "irc_res.h"
39 #include "irc_reslib.h"
40 #include "irc_getnameinfo.h"
41 #include "common.h"
42
43 #if (CHAR_BIT != 8)
44 #error this code needs to be able to address individual octets
45 #endif
46
47 static PF res_readreply;
48
49 #define MAXPACKET 1024 /* rfc sez 512 but we expand names so ... */
50 #define RES_MAXALIASES 35 /* maximum aliases allowed */
51 #define RES_MAXADDRS 35 /* maximum addresses allowed */
52 #define AR_TTL 600 /* TTL in seconds for dns cache entries */
53
54 /* RFC 1104/1105 wasn't very helpful about what these fields
55 * should be named, so for now, we'll just name them this way.
56 * we probably should look at what named calls them or something.
57 */
58 #define TYPE_SIZE (size_t)2
59 #define CLASS_SIZE (size_t)2
60 #define TTL_SIZE (size_t)4
61 #define RDLENGTH_SIZE (size_t)2
62 #define ANSWER_FIXED_SIZE (TYPE_SIZE + CLASS_SIZE + TTL_SIZE + RDLENGTH_SIZE)
63
64 typedef enum
65 {
66 REQ_IDLE, /* We're doing not much at all */
67 REQ_PTR, /* Looking up a PTR */
68 REQ_A, /* Looking up an A, possibly because AAAA failed */
69 #ifdef IPV6
70 REQ_AAAA, /* Looking up an AAAA */
71 #endif
72 REQ_CNAME /* We got a CNAME in response, we better get a real answer next */
73 } request_state;
74
75 struct reslist
76 {
77 dlink_node node;
78 int id;
79 int sent; /* number of requests sent */
80 request_state state; /* State the resolver machine is in */
81 time_t ttl;
82 char type;
83 char retries; /* retry counter */
84 char sends; /* number of sends (>1 means resent) */
85 char resend; /* send flag. 0 == dont resend */
86 time_t sentat;
87 time_t timeout;
88 struct irc_ssaddr addr;
89 char *name;
90 dns_callback_fnc callback;
91 void *callback_ctx;
92 };
93
94 static fde_t ResolverFileDescriptor;
95 static dlink_list request_list = { NULL, NULL, 0 };
96 static BlockHeap *dns_heap = NULL;
97
98 static void rem_request(struct reslist *request);
99 static struct reslist *make_request(dns_callback_fnc callback, void *);
100 static void do_query_name(dns_callback_fnc callback, void *,
101 const char *, struct reslist *, int);
102 static void do_query_number(dns_callback_fnc callback, void *ctx,
103 const struct irc_ssaddr *,
104 struct reslist *request);
105 static void query_name(const char *name, int query_class, int query_type,
106 struct reslist *request);
107 static int send_res_msg(const char *buf, int len, int count);
108 static void resend_query(struct reslist *request);
109 static int proc_answer(struct reslist *request, HEADER *header, char *, char *);
110 static struct reslist *find_id(int id);
111
112
113 /*
114 * int
115 * res_ourserver(inp)
116 * looks up "inp" in irc_nsaddr_list[]
117 * returns:
118 * 0 : not found
119 * >0 : found
120 * author:
121 * paul vixie, 29may94
122 * revised for ircd, cryogen(stu) may03
123 */
124 static int
125 res_ourserver(const struct irc_ssaddr *inp)
126 {
127 #ifdef IPV6
128 const struct sockaddr_in6 *v6;
129 const struct sockaddr_in6 *v6in = (const struct sockaddr_in6 *)inp;
130 #endif
131 const struct sockaddr_in *v4;
132 const struct sockaddr_in *v4in = (const struct sockaddr_in *)inp;
133 int ns;
134
135 for (ns = 0; ns < irc_nscount; ns++)
136 {
137 const struct irc_ssaddr *srv = &irc_nsaddr_list[ns];
138 #ifdef IPV6
139 v6 = (const struct sockaddr_in6 *)srv;
140 #endif
141 v4 = (const struct sockaddr_in *)srv;
142
143 /* could probably just memcmp(srv, inp, srv.ss_len) here
144 * but we'll air on the side of caution - stu
145 *
146 */
147 switch (srv->ss.ss_family)
148 {
149 #ifdef IPV6
150 case AF_INET6:
151 if (srv->ss.ss_family == inp->ss.ss_family)
152 if (v6->sin6_port == v6in->sin6_port)
153 if ((memcmp(&v6->sin6_addr.s6_addr, &v6in->sin6_addr.s6_addr,
154 sizeof(struct in6_addr)) == 0) ||
155 (memcmp(&v6->sin6_addr.s6_addr, &in6addr_any,
156 sizeof(struct in6_addr)) == 0))
157 return(1);
158 break;
159 #endif
160 case AF_INET:
161 if (srv->ss.ss_family == inp->ss.ss_family)
162 if (v4->sin_port == v4in->sin_port)
163 if ((v4->sin_addr.s_addr == INADDR_ANY) ||
164 (v4->sin_addr.s_addr == v4in->sin_addr.s_addr))
165 return(1);
166 break;
167 default:
168 break;
169 }
170 }
171
172 return(0);
173 }
174
175 /*
176 * timeout_query_list - Remove queries from the list which have been
177 * there too long without being resolved.
178 */
179 static time_t
180 timeout_query_list(time_t now)
181 {
182 dlink_node *ptr;
183 dlink_node *next_ptr;
184 struct reslist *request;
185 time_t next_time = 0;
186 time_t timeout = 0;
187
188 DLINK_FOREACH_SAFE(ptr, next_ptr, request_list.head)
189 {
190 request = ptr->data;
191 timeout = request->sentat + request->timeout;
192
193 if (now >= timeout)
194 {
195 if (--request->retries <= 0)
196 {
197 (*request->callback)(request->callback_ctx, NULL, NULL);
198 rem_request(request);
199 continue;
200 }
201 else
202 {
203 request->sentat = now;
204 request->timeout += request->timeout;
205 resend_query(request);
206 }
207 }
208
209 if ((next_time == 0) || timeout < next_time)
210 {
211 next_time = timeout;
212 }
213 }
214
215 return((next_time > now) ? next_time : (now + AR_TTL));
216 }
217
218 /*
219 * timeout_resolver - check request list
220 */
221 static void
222 timeout_resolver(void *notused)
223 {
224 timeout_query_list(CurrentTime);
225 }
226
227 /*
228 * start_resolver - do everything we need to read the resolv.conf file
229 * and initialize the resolver file descriptor if needed
230 */
231 static void
232 start_resolver(void)
233 {
234 irc_res_init();
235
236 if (!ResolverFileDescriptor.flags.open)
237 {
238 if (comm_open(&ResolverFileDescriptor, irc_nsaddr_list[0].ss.ss_family,
239 SOCK_DGRAM, 0, "Resolver socket") == -1)
240 return;
241
242 /* At the moment, the resolver FD data is global .. */
243 comm_setselect(&ResolverFileDescriptor, COMM_SELECT_READ,
244 res_readreply, NULL, 0);
245 eventAdd("timeout_resolver", timeout_resolver, NULL, 1);
246 }
247 }
248
249 /*
250 * init_resolver - initialize resolver and resolver library
251 */
252 void
253 init_resolver(void)
254 {
255 dns_heap = BlockHeapCreate("dns", sizeof(struct reslist), DNS_HEAP_SIZE);
256 memset(&ResolverFileDescriptor, 0, sizeof(fde_t));
257 start_resolver();
258 }
259
260 /*
261 * restart_resolver - reread resolv.conf, reopen socket
262 */
263 void
264 restart_resolver(void)
265 {
266 fd_close(&ResolverFileDescriptor);
267 eventDelete(timeout_resolver, NULL); /* -ddosen */
268 start_resolver();
269 }
270
271 /*
272 * rem_request - remove a request from the list.
273 * This must also free any memory that has been allocated for
274 * temporary storage of DNS results.
275 */
276 static void
277 rem_request(struct reslist *request)
278 {
279 dlinkDelete(&request->node, &request_list);
280
281 MyFree(request->name);
282 BlockHeapFree(dns_heap, request);
283 }
284
285 /*
286 * make_request - Create a DNS request record for the server.
287 */
288 static struct reslist *
289 make_request(dns_callback_fnc callback, void *ctx)
290 {
291 struct reslist *request = BlockHeapAlloc(dns_heap);
292
293 request->sentat = CurrentTime;
294 request->retries = 3;
295 request->resend = 1;
296 request->timeout = 4; /* start at 4 and exponential inc. */
297 request->state = REQ_IDLE;
298 request->callback = callback;
299 request->callback_ctx = ctx;
300
301 dlinkAdd(request, &request->node, &request_list);
302 return request;
303 }
304
305 /*
306 * delete_resolver_queries - cleanup outstanding queries
307 * for which there no longer exist clients or conf lines.
308 */
309 void
310 delete_resolver_queries(const void *vptr)
311 {
312 dlink_node *ptr = NULL, *next_ptr = NULL;
313
314 DLINK_FOREACH_SAFE(ptr, next_ptr, request_list.head)
315 {
316 struct reslist *request = ptr->data;
317
318 if (request->callback_ctx == vptr)
319 rem_request(request);
320 }
321 }
322
323 /*
324 * send_res_msg - sends msg to all nameservers found in the "_res" structure.
325 * This should reflect /etc/resolv.conf. We will get responses
326 * which arent needed but is easier than checking to see if nameserver
327 * isnt present. Returns number of messages successfully sent to
328 * nameservers or -1 if no successful sends.
329 */
330 static int
331 send_res_msg(const char *msg, int len, int rcount)
332 {
333 int i;
334 int sent = 0;
335 int max_queries = IRCD_MIN(irc_nscount, rcount);
336
337 /* RES_PRIMARY option is not implemented
338 * if (res.options & RES_PRIMARY || 0 == max_queries)
339 */
340 if (max_queries == 0)
341 max_queries = 1;
342
343 for (i = 0; i < max_queries; i++)
344 {
345 if (sendto(ResolverFileDescriptor.fd, msg, len, 0,
346 (struct sockaddr*)&(irc_nsaddr_list[i]),
347 irc_nsaddr_list[i].ss_len) == len)
348 ++sent;
349 }
350
351 return(sent);
352 }
353
354 /*
355 * find_id - find a dns request id (id is determined by dn_mkquery)
356 */
357 static struct reslist *
358 find_id(int id)
359 {
360 dlink_node *ptr;
361 struct reslist *request;
362
363 DLINK_FOREACH(ptr, request_list.head)
364 {
365 request = ptr->data;
366
367 if (request->id == id)
368 return(request);
369 }
370
371 return(NULL);
372 }
373
374 /*
375 * gethost_byname_type - get host address from name
376 *
377 */
378 void
379 gethost_byname_type(dns_callback_fnc callback, void *ctx, const char *name, int type)
380 {
381 assert(name != 0);
382 do_query_name(callback, ctx, name, NULL, type);
383 }
384
385 /*
386 * gethost_byname - wrapper for _type - send T_AAAA first if IPV6 supported
387 */
388 void
389 gethost_byname(dns_callback_fnc callback, void *ctx, const char *name)
390 {
391 #ifdef IPV6
392 gethost_byname_type(callback, ctx, name, T_AAAA);
393 #else
394 gethost_byname_type(callback, ctx, name, T_A);
395 #endif
396 }
397
398 /*
399 * gethost_byaddr - get host name from address
400 */
401 void
402 gethost_byaddr(dns_callback_fnc callback, void *ctx, const struct irc_ssaddr *addr)
403 {
404 do_query_number(callback, ctx, addr, NULL);
405 }
406
407 /*
408 * do_query_name - nameserver lookup name
409 */
410 static void
411 do_query_name(dns_callback_fnc callback, void *ctx, const char *name,
412 struct reslist *request, int type)
413 {
414 char host_name[HOSTLEN + 1];
415
416 strlcpy(host_name, name, sizeof(host_name));
417
418 if (request == NULL)
419 {
420 request = make_request(callback, ctx);
421 request->name = MyMalloc(strlen(host_name) + 1);
422 request->type = type;
423 strcpy(request->name, host_name);
424 #ifdef IPV6
425 if (type != T_A)
426 request->state = REQ_AAAA;
427 else
428 #endif
429 request->state = REQ_A;
430 }
431
432 request->type = type;
433 query_name(host_name, C_IN, type, request);
434 }
435
436 /*
437 * do_query_number - Use this to do reverse IP# lookups.
438 */
439 static void
440 do_query_number(dns_callback_fnc callback, void *ctx,
441 const struct irc_ssaddr *addr,
442 struct reslist *request)
443 {
444 char ipbuf[128];
445 const unsigned char *cp;
446
447 if (addr->ss.ss_family == AF_INET)
448 {
449 const struct sockaddr_in *v4 = (const struct sockaddr_in *)addr;
450 cp = (const unsigned char*)&v4->sin_addr.s_addr;
451
452 ircsprintf(ipbuf, "%u.%u.%u.%u.in-addr.arpa.",
453 (unsigned int)(cp[3]), (unsigned int)(cp[2]),
454 (unsigned int)(cp[1]), (unsigned int)(cp[0]));
455 }
456 #ifdef IPV6
457 else if (addr->ss.ss_family == AF_INET6)
458 {
459 const struct sockaddr_in6 *v6 = (const struct sockaddr_in6 *)addr;
460 cp = (const unsigned char *)&v6->sin6_addr.s6_addr;
461
462 sprintf(ipbuf, "%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x."
463 "%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.ip6.arpa.",
464 (unsigned int)(cp[15]&0xf), (unsigned int)(cp[15]>>4),
465 (unsigned int)(cp[14]&0xf), (unsigned int)(cp[14]>>4),
466 (unsigned int)(cp[13]&0xf), (unsigned int)(cp[13]>>4),
467 (unsigned int)(cp[12]&0xf), (unsigned int)(cp[12]>>4),
468 (unsigned int)(cp[11]&0xf), (unsigned int)(cp[11]>>4),
469 (unsigned int)(cp[10]&0xf), (unsigned int)(cp[10]>>4),
470 (unsigned int)(cp[9]&0xf), (unsigned int)(cp[9]>>4),
471 (unsigned int)(cp[8]&0xf), (unsigned int)(cp[8]>>4),
472 (unsigned int)(cp[7]&0xf), (unsigned int)(cp[7]>>4),
473 (unsigned int)(cp[6]&0xf), (unsigned int)(cp[6]>>4),
474 (unsigned int)(cp[5]&0xf), (unsigned int)(cp[5]>>4),
475 (unsigned int)(cp[4]&0xf), (unsigned int)(cp[4]>>4),
476 (unsigned int)(cp[3]&0xf), (unsigned int)(cp[3]>>4),
477 (unsigned int)(cp[2]&0xf), (unsigned int)(cp[2]>>4),
478 (unsigned int)(cp[1]&0xf), (unsigned int)(cp[1]>>4),
479 (unsigned int)(cp[0]&0xf), (unsigned int)(cp[0]>>4));
480 }
481 #endif
482 if (request == NULL)
483 {
484 request = make_request(callback, ctx);
485 request->type = T_PTR;
486 memcpy(&request->addr, addr, sizeof(struct irc_ssaddr));
487 request->name = MyMalloc(HOSTLEN + 1);
488 }
489
490 query_name(ipbuf, C_IN, T_PTR, request);
491 }
492
493 /*
494 * query_name - generate a query based on class, type and name.
495 */
496 static void
497 query_name(const char *name, int query_class, int type,
498 struct reslist *request)
499 {
500 char buf[MAXPACKET];
501 int request_len = 0;
502
503 memset(buf, 0, sizeof(buf));
504
505 if ((request_len = irc_res_mkquery(name, query_class, type,
506 (unsigned char *)buf, sizeof(buf))) > 0)
507 {
508 HEADER *header = (HEADER *)buf;
509
510 /*
511 * generate an unique id
512 * NOTE: we don't have to worry about converting this to and from
513 * network byte order, the nameserver does not interpret this value
514 * and returns it unchanged
515 */
516 do
517 header->id = (header->id + genrand_int32()) & 0xffff;
518 while (find_id(header->id));
519
520 request->id = header->id;
521 ++request->sends;
522
523 request->sent += send_res_msg(buf, request_len, request->sends);
524 }
525 }
526
527 static void
528 resend_query(struct reslist *request)
529 {
530 if (request->resend == 0)
531 return;
532
533 switch (request->type)
534 {
535 case T_PTR:
536 do_query_number(NULL, NULL, &request->addr, request);
537 break;
538 case T_A:
539 do_query_name(NULL, NULL, request->name, request, request->type);
540 break;
541 #ifdef IPV6
542 case T_AAAA:
543 /* didnt work, try A */
544 if (request->state == REQ_AAAA)
545 do_query_name(NULL, NULL, request->name, request, T_A);
546 #endif
547 default:
548 break;
549 }
550 }
551
552 /*
553 * proc_answer - process name server reply
554 */
555 static int
556 proc_answer(struct reslist *request, HEADER* header, char* buf, char* eob)
557 {
558 char hostbuf[HOSTLEN + 100]; /* working buffer */
559 unsigned char *current; /* current position in buf */
560 int query_class; /* answer class */
561 int type; /* answer type */
562 int n; /* temp count */
563 int rd_length;
564 struct sockaddr_in *v4; /* conversion */
565 #ifdef IPV6
566 struct sockaddr_in6 *v6;
567 #endif
568 current = (unsigned char *)buf + sizeof(HEADER);
569
570 for (; header->qdcount > 0; --header->qdcount)
571 {
572 if ((n = irc_dn_skipname(current, (unsigned char *)eob)) < 0)
573 break;
574
575 current += (size_t) n + QFIXEDSZ;
576 }
577
578 /*
579 * process each answer sent to us blech.
580 */
581 while (header->ancount > 0 && (char *)current < eob)
582 {
583 header->ancount--;
584
585 n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob, current,
586 hostbuf, sizeof(hostbuf));
587
588 if (n < 0)
589 {
590 /*
591 * broken message
592 */
593 return(0);
594 }
595 else if (n == 0)
596 {
597 /*
598 * no more answers left
599 */
600 return(0);
601 }
602
603 hostbuf[HOSTLEN] = '\0';
604
605 /* With Address arithmetic you have to be very anal
606 * this code was not working on alpha due to that
607 * (spotted by rodder/jailbird/dianora)
608 */
609 current += (size_t) n;
610
611 if (!(((char *)current + ANSWER_FIXED_SIZE) < eob))
612 break;
613
614 type = irc_ns_get16(current);
615 current += TYPE_SIZE;
616
617 query_class = irc_ns_get16(current);
618 current += CLASS_SIZE;
619
620 request->ttl = irc_ns_get32(current);
621 current += TTL_SIZE;
622
623 rd_length = irc_ns_get16(current);
624 current += RDLENGTH_SIZE;
625
626 /*
627 * Wait to set request->type until we verify this structure
628 */
629 switch (type)
630 {
631 case T_A:
632 if (request->type != T_A)
633 return(0);
634
635 /*
636 * check for invalid rd_length or too many addresses
637 */
638 if (rd_length != sizeof(struct in_addr))
639 return(0);
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 if (rd_length != sizeof(struct in6_addr))
651 return(0);
652 request->addr.ss_len = sizeof(struct sockaddr_in6);
653 v6 = (struct sockaddr_in6 *)&request->addr;
654 v6->sin6_family = AF_INET6;
655 memcpy(&v6->sin6_addr, current, sizeof(struct in6_addr));
656 return(1);
657 break;
658 #endif
659 case T_PTR:
660 if (request->type != T_PTR)
661 return(0);
662 n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob,
663 current, hostbuf, sizeof(hostbuf));
664 if (n < 0)
665 return(0); /* broken message */
666 else if (n == 0)
667 return(0); /* no more answers left */
668
669 strlcpy(request->name, hostbuf, HOSTLEN + 1);
670
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(L_ERROR, "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
809 * ip#.
810 *
811 */
812 #ifdef IPV6
813 if (request->addr.ss.ss_family == AF_INET6)
814 gethost_byname_type(request->callback, request->callback_ctx, request->name, T_AAAA);
815 else
816 #endif
817 gethost_byname_type(request->callback, request->callback_ctx, request->name, T_A);
818 rem_request(request);
819 }
820 else
821 {
822 /*
823 * got a name and address response, client resolved
824 */
825 (*request->callback)(request->callback_ctx, &request->addr, request->name);
826 rem_request(request);
827 }
828 }
829 else if (!request->sent)
830 {
831 /* XXX - we got a response for a query we didn't send with a valid id?
832 * this should never happen, bail here and leave the client unresolved
833 */
834 assert(0);
835
836 /* XXX don't leak it */
837 rem_request(request);
838 }
839 }
840
841 void
842 report_dns_servers(struct Client *source_p)
843 {
844 int i;
845 char ipaddr[HOSTIPLEN + 1];
846
847 for (i = 0; i < irc_nscount; i++)
848 {
849 irc_getnameinfo((struct sockaddr *)&(irc_nsaddr_list[i]),
850 irc_nsaddr_list[i].ss_len, ipaddr,
851 sizeof(ipaddr), NULL, 0, NI_NUMERICHOST);
852 sendto_one(source_p, form_str(RPL_STATSALINE),
853 me.name, source_p->name, ipaddr);
854 }
855 }

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