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root/svn/ircd-hybrid/branches/8.2.x/src/res.c
Revision: 4312
Committed: Thu Jul 31 17:02:26 2014 UTC (9 years, 7 months ago) by michael
Content type: text/x-csrc
File size: 22721 byte(s)
Log Message:
- res.c: reformatting; style corrections; updated comments

File Contents

# User Rev Content
1 adx 30 /*
2 michael 2916 * 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 michael 3322 /*! \file res.c
23 michael 2916 * \brief ircd resolver functions
24     * \version $Id$
25     */
26    
27     /*
28 michael 4312 * A rewrite of Darren Reed's original res.c As there is nothing
29     * left of Darren's original code, this is now licensed by the hybrid group.
30 adx 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     * July 1999 - Rewrote a bunch of stuff here. Change hostent builder code,
37     * added callbacks and reference counting of returned hostents.
38     * --Bleep (Thomas Helvey <tomh@inxpress.net>)
39     *
40     * This was all needlessly complicated for irc. Simplified. No more hostent
41 michael 4312 * All we really care about is the IP -> hostname mappings. That's all.
42 adx 30 *
43     * Apr 28, 2003 --cryogen and Dianora
44     */
45    
46     #include "stdinc.h"
47 michael 1011 #include "list.h"
48 adx 30 #include "client.h"
49     #include "event.h"
50     #include "irc_string.h"
51     #include "ircd.h"
52     #include "numeric.h"
53 michael 982 #include "rng_mt.h"
54 adx 30 #include "fdlist.h"
55     #include "s_bsd.h"
56 michael 1309 #include "log.h"
57 michael 3347 #include "misc.h"
58 adx 30 #include "send.h"
59     #include "memory.h"
60 michael 1654 #include "mempool.h"
61 michael 3322 #include "res.h"
62     #include "reslib.h"
63 adx 30
64     #if (CHAR_BIT != 8)
65 michael 2916 #error this code needs to be able to address individual octets
66 adx 30 #endif
67    
68     static PF res_readreply;
69    
70 michael 4312 #define MAXPACKET 1024 /**< rfc says 512 but we expand names so ... */
71     #define AR_TTL 600 /**< TTL in seconds for dns cache entries */
72 adx 30
73 michael 4312 /*
74     * RFC 1104/1105 wasn't very helpful about what these fields
75 adx 30 * should be named, so for now, we'll just name them this way.
76 michael 4312 * We probably should look at what named calls them or something.
77 adx 30 */
78     #define TYPE_SIZE (size_t)2
79     #define CLASS_SIZE (size_t)2
80     #define TTL_SIZE (size_t)4
81     #define RDLENGTH_SIZE (size_t)2
82     #define ANSWER_FIXED_SIZE (TYPE_SIZE + CLASS_SIZE + TTL_SIZE + RDLENGTH_SIZE)
83    
84 michael 2916 typedef enum
85 adx 30 {
86 michael 4312 REQ_IDLE, /**< We're doing not much at all */
87     REQ_PTR, /**< Looking up a PTR */
88     REQ_A, /**< Looking up an A, possibly because AAAA failed */
89 adx 30 #ifdef IPV6
90 michael 4312 REQ_AAAA, /**< Looking up an AAAA */
91 adx 30 #endif
92 michael 4312 REQ_CNAME /**< We got a CNAME in response, we better get a real answer next */
93 adx 30 } request_state;
94    
95 michael 2916 struct reslist
96 adx 30 {
97 michael 4312 dlink_node node; /**< Doubly linked list node. */
98     int id; /**< Request ID (from request header). */
99     int sent; /**< Number of requests sent */
100     request_state state; /**< State the resolver machine is in */
101     char type; /**< Current request type. */
102     char retries; /**< Retry counter */
103     unsigned int sends; /**< Number of sends (>1 means resent). */
104     char resend; /**< Send flag; 0 == don't resend. */
105     time_t sentat; /**< Timestamp we last sent this request. */
106     time_t timeout; /**< When this request times out. */
107     struct irc_ssaddr addr; /**< Address for this request. */
108     char *name; /**< Hostname for this request. */
109     dns_callback_fnc callback; /**< Callback function on completion. */
110     void *callback_ctx; /**< Context pointer for callback. */
111 adx 30 };
112    
113     static fde_t ResolverFileDescriptor;
114 michael 3235 static dlink_list request_list;
115     static mp_pool_t *dns_pool;
116 adx 30
117    
118 michael 4312 /*
119     * rem_request - remove a request from the list.
120     * This must also free any memory that has been allocated for
121     * temporary storage of DNS results.
122     */
123     static void
124     rem_request(struct reslist *request)
125     {
126     dlinkDelete(&request->node, &request_list);
127 adx 30
128 michael 4312 MyFree(request->name);
129     mp_pool_release(request);
130     }
131    
132 adx 30 /*
133 michael 4312 * make_request - Create a DNS request record for the server.
134     */
135     static struct reslist *
136     make_request(dns_callback_fnc callback, void *ctx)
137     {
138     struct reslist *request = mp_pool_get(dns_pool);
139    
140     request->sentat = CurrentTime;
141     request->retries = 2;
142     request->resend = 1;
143     request->timeout = 4; /* Start at 4 and exponential inc. */
144     request->state = REQ_IDLE;
145     request->callback = callback;
146     request->callback_ctx = ctx;
147    
148     dlinkAdd(request, &request->node, &request_list);
149     return request;
150     }
151    
152     /*
153 adx 30 * int
154     * res_ourserver(inp)
155     * looks up "inp" in irc_nsaddr_list[]
156     * returns:
157     * 0 : not found
158     * >0 : found
159     * author:
160     * paul vixie, 29may94
161     * revised for ircd, cryogen(stu) may03
162     */
163     static int
164 michael 2916 res_ourserver(const struct irc_ssaddr *inp)
165 adx 30 {
166     #ifdef IPV6
167 michael 992 const struct sockaddr_in6 *v6;
168     const struct sockaddr_in6 *v6in = (const struct sockaddr_in6 *)inp;
169 adx 30 #endif
170 michael 992 const struct sockaddr_in *v4;
171 michael 2916 const struct sockaddr_in *v4in = (const struct sockaddr_in *)inp;
172 adx 30
173 michael 3297 for (unsigned int i = 0; i < irc_nscount; ++i)
174 adx 30 {
175 michael 3235 const struct irc_ssaddr *srv = &irc_nsaddr_list[i];
176 adx 30 #ifdef IPV6
177 michael 992 v6 = (const struct sockaddr_in6 *)srv;
178 adx 30 #endif
179 michael 992 v4 = (const struct sockaddr_in *)srv;
180 adx 30
181 michael 4312 /*
182     * Could probably just memcmp(srv, inp, srv.ss_len) here
183 adx 30 * but we'll air on the side of caution - stu
184     */
185     switch (srv->ss.ss_family)
186     {
187     #ifdef IPV6
188     case AF_INET6:
189     if (srv->ss.ss_family == inp->ss.ss_family)
190     if (v6->sin6_port == v6in->sin6_port)
191 michael 1346 if (!memcmp(&v6->sin6_addr.s6_addr, &v6in->sin6_addr.s6_addr,
192     sizeof(struct in6_addr)))
193 michael 1124 return 1;
194 adx 30 break;
195     #endif
196     case AF_INET:
197     if (srv->ss.ss_family == inp->ss.ss_family)
198     if (v4->sin_port == v4in->sin_port)
199 michael 1346 if (v4->sin_addr.s_addr == v4in->sin_addr.s_addr)
200 michael 1124 return 1;
201 adx 30 break;
202     default:
203     break;
204     }
205     }
206    
207 michael 1124 return 0;
208 adx 30 }
209    
210     /*
211     * start_resolver - do everything we need to read the resolv.conf file
212     * and initialize the resolver file descriptor if needed
213     */
214     static void
215     start_resolver(void)
216     {
217     irc_res_init();
218    
219     if (!ResolverFileDescriptor.flags.open)
220     {
221     if (comm_open(&ResolverFileDescriptor, irc_nsaddr_list[0].ss.ss_family,
222     SOCK_DGRAM, 0, "Resolver socket") == -1)
223     return;
224    
225     /* At the moment, the resolver FD data is global .. */
226 michael 3298 comm_setselect(&ResolverFileDescriptor, COMM_SELECT_READ, res_readreply, NULL, 0);
227 adx 30 }
228     }
229    
230     /*
231     * restart_resolver - reread resolv.conf, reopen socket
232     */
233     void
234     restart_resolver(void)
235     {
236     fd_close(&ResolverFileDescriptor);
237     start_resolver();
238     }
239    
240     /*
241 michael 2916 * delete_resolver_queries - cleanup outstanding queries
242 adx 30 * for which there no longer exist clients or conf lines.
243     */
244     void
245 michael 992 delete_resolver_queries(const void *vptr)
246 adx 30 {
247 michael 3235 dlink_node *ptr = NULL, *ptr_next = NULL;
248 adx 30
249 michael 3235 DLINK_FOREACH_SAFE(ptr, ptr_next, request_list.head)
250 adx 30 {
251 michael 997 struct reslist *request = ptr->data;
252    
253     if (request->callback_ctx == vptr)
254     rem_request(request);
255 adx 30 }
256     }
257    
258     /*
259     * send_res_msg - sends msg to all nameservers found in the "_res" structure.
260     * This should reflect /etc/resolv.conf. We will get responses
261     * which arent needed but is easier than checking to see if nameserver
262 michael 4299 * isn't present. Returns number of messages successfully sent to
263 adx 30 * nameservers or -1 if no successful sends.
264     */
265     static int
266 michael 3297 send_res_msg(const char *msg, int len, unsigned int rcount)
267 adx 30 {
268     int sent = 0;
269 michael 3297 unsigned int max_queries = IRCD_MIN(irc_nscount, rcount);
270 adx 30
271     /* RES_PRIMARY option is not implemented
272     * if (res.options & RES_PRIMARY || 0 == max_queries)
273     */
274     if (max_queries == 0)
275     max_queries = 1;
276    
277 michael 3297 for (unsigned int i = 0; i < max_queries; ++i)
278 adx 30 {
279 michael 2916 if (sendto(ResolverFileDescriptor.fd, msg, len, 0,
280     (struct sockaddr*)&(irc_nsaddr_list[i]),
281     irc_nsaddr_list[i].ss_len) == len)
282 adx 30 ++sent;
283     }
284    
285 michael 1124 return sent;
286 adx 30 }
287    
288     /*
289     * find_id - find a dns request id (id is determined by dn_mkquery)
290     */
291     static struct reslist *
292     find_id(int id)
293     {
294 michael 1124 dlink_node *ptr = NULL;
295 adx 30
296     DLINK_FOREACH(ptr, request_list.head)
297     {
298 michael 1124 struct reslist *request = ptr->data;
299 adx 30
300     if (request->id == id)
301 michael 1124 return request;
302 adx 30 }
303    
304 michael 1124 return NULL;
305 adx 30 }
306    
307 michael 2916 /*
308 michael 4312 * query_name - generate a query based on class, type and name.
309 adx 30 */
310 michael 4312 static void
311     query_name(const char *name, int query_class, int type,
312     struct reslist *request)
313 adx 30 {
314 michael 4312 char buf[MAXPACKET];
315     int request_len = 0;
316 adx 30
317 michael 4312 memset(buf, 0, sizeof(buf));
318 adx 30
319 michael 4312 if ((request_len = irc_res_mkquery(name, query_class, type,
320     (unsigned char *)buf, sizeof(buf))) > 0)
321     {
322     HEADER *header = (HEADER *)buf;
323    
324     /*
325     * Generate an unique id.
326     * NOTE: we don't have to worry about converting this to and from
327     * network byte order, the nameserver does not interpret this value
328     * and returns it unchanged.
329     */
330     do
331     header->id = (header->id + genrand_int32()) & 0xFFFF;
332     while (find_id(header->id));
333    
334     request->id = header->id;
335     ++request->sends;
336    
337     request->sent += send_res_msg(buf, request_len, request->sends);
338     }
339 adx 30 }
340    
341     /*
342     * do_query_name - nameserver lookup name
343     */
344     static void
345 michael 992 do_query_name(dns_callback_fnc callback, void *ctx, const char *name,
346 adx 30 struct reslist *request, int type)
347     {
348     char host_name[HOSTLEN + 1];
349    
350 michael 998 strlcpy(host_name, name, sizeof(host_name));
351 adx 30
352     if (request == NULL)
353     {
354 michael 992 request = make_request(callback, ctx);
355 michael 3505 request->name = MyCalloc(strlen(host_name) + 1);
356 adx 30 request->type = type;
357     strcpy(request->name, host_name);
358     #ifdef IPV6
359 michael 984 if (type != T_A)
360     request->state = REQ_AAAA;
361 adx 30 else
362 michael 984 #endif
363 adx 30 request->state = REQ_A;
364     }
365    
366     request->type = type;
367     query_name(host_name, C_IN, type, request);
368     }
369    
370     /*
371     * do_query_number - Use this to do reverse IP# lookups.
372     */
373     static void
374 michael 992 do_query_number(dns_callback_fnc callback, void *ctx,
375     const struct irc_ssaddr *addr,
376 adx 30 struct reslist *request)
377     {
378 michael 3298 char ipbuf[128] = "";
379 michael 985
380 adx 30 if (addr->ss.ss_family == AF_INET)
381     {
382 michael 992 const struct sockaddr_in *v4 = (const struct sockaddr_in *)addr;
383 michael 3298 const unsigned char *cp = (const unsigned char *)&v4->sin_addr.s_addr;
384 adx 30
385 michael 1124 snprintf(ipbuf, sizeof(ipbuf), "%u.%u.%u.%u.in-addr.arpa.",
386     (unsigned int)(cp[3]), (unsigned int)(cp[2]),
387     (unsigned int)(cp[1]), (unsigned int)(cp[0]));
388 adx 30 }
389     #ifdef IPV6
390     else if (addr->ss.ss_family == AF_INET6)
391     {
392 michael 992 const struct sockaddr_in6 *v6 = (const struct sockaddr_in6 *)addr;
393 michael 3298 const unsigned char *cp = (const unsigned char *)&v6->sin6_addr.s6_addr;
394 adx 30
395 michael 1124 snprintf(ipbuf, sizeof(ipbuf),
396     "%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x."
397     "%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.ip6.arpa.",
398     (unsigned int)(cp[15] & 0xf), (unsigned int)(cp[15] >> 4),
399     (unsigned int)(cp[14] & 0xf), (unsigned int)(cp[14] >> 4),
400     (unsigned int)(cp[13] & 0xf), (unsigned int)(cp[13] >> 4),
401     (unsigned int)(cp[12] & 0xf), (unsigned int)(cp[12] >> 4),
402     (unsigned int)(cp[11] & 0xf), (unsigned int)(cp[11] >> 4),
403     (unsigned int)(cp[10] & 0xf), (unsigned int)(cp[10] >> 4),
404     (unsigned int)(cp[9] & 0xf), (unsigned int)(cp[9] >> 4),
405     (unsigned int)(cp[8] & 0xf), (unsigned int)(cp[8] >> 4),
406     (unsigned int)(cp[7] & 0xf), (unsigned int)(cp[7] >> 4),
407     (unsigned int)(cp[6] & 0xf), (unsigned int)(cp[6] >> 4),
408     (unsigned int)(cp[5] & 0xf), (unsigned int)(cp[5] >> 4),
409     (unsigned int)(cp[4] & 0xf), (unsigned int)(cp[4] >> 4),
410     (unsigned int)(cp[3] & 0xf), (unsigned int)(cp[3] >> 4),
411     (unsigned int)(cp[2] & 0xf), (unsigned int)(cp[2] >> 4),
412     (unsigned int)(cp[1] & 0xf), (unsigned int)(cp[1] >> 4),
413     (unsigned int)(cp[0] & 0xf), (unsigned int)(cp[0] >> 4));
414 adx 30 }
415     #endif
416     if (request == NULL)
417     {
418 michael 992 request = make_request(callback, ctx);
419 adx 30 request->type = T_PTR;
420     memcpy(&request->addr, addr, sizeof(struct irc_ssaddr));
421 michael 3505 request->name = MyCalloc(HOSTLEN + 1);
422 adx 30 }
423    
424     query_name(ipbuf, C_IN, T_PTR, request);
425     }
426    
427     /*
428 michael 4312 * gethost_byname_type - get host address from name
429     *
430 adx 30 */
431 michael 4312 void
432     gethost_byname_type(dns_callback_fnc callback, void *ctx, const char *name, int type)
433 adx 30 {
434 michael 4312 assert(name);
435     do_query_name(callback, ctx, name, NULL, type);
436     }
437 adx 30
438 michael 4312 /*
439     * gethost_byname - wrapper for _type - send T_AAAA first if IPV6 supported
440     */
441     void
442     gethost_byname(dns_callback_fnc callback, void *ctx, const char *name)
443     {
444     #ifdef IPV6
445     gethost_byname_type(callback, ctx, name, T_AAAA);
446     #else
447     gethost_byname_type(callback, ctx, name, T_A);
448     #endif
449     }
450 adx 30
451 michael 4312 /*
452     * gethost_byaddr - get host name from address
453     */
454     void
455     gethost_byaddr(dns_callback_fnc callback, void *ctx, const struct irc_ssaddr *addr)
456     {
457     do_query_number(callback, ctx, addr, NULL);
458 adx 30 }
459    
460     static void
461     resend_query(struct reslist *request)
462     {
463     if (request->resend == 0)
464     return;
465    
466 michael 982 switch (request->type)
467 adx 30 {
468     case T_PTR:
469 michael 992 do_query_number(NULL, NULL, &request->addr, request);
470 adx 30 break;
471     case T_A:
472 michael 992 do_query_name(NULL, NULL, request->name, request, request->type);
473 adx 30 break;
474     #ifdef IPV6
475 michael 4299 case T_AAAA: /* Didn't work, try A */
476 adx 30 if (request->state == REQ_AAAA)
477 michael 992 do_query_name(NULL, NULL, request->name, request, T_A);
478 adx 30 #endif
479     default:
480     break;
481     }
482     }
483    
484     /*
485     * proc_answer - process name server reply
486     */
487     static int
488 michael 1124 proc_answer(struct reslist *request, HEADER *header, char *buf, char *eob)
489 adx 30 {
490     char hostbuf[HOSTLEN + 100]; /* working buffer */
491     unsigned char *current; /* current position in buf */
492     int type; /* answer type */
493     int n; /* temp count */
494     int rd_length;
495     struct sockaddr_in *v4; /* conversion */
496     #ifdef IPV6
497     struct sockaddr_in6 *v6;
498     #endif
499     current = (unsigned char *)buf + sizeof(HEADER);
500    
501     for (; header->qdcount > 0; --header->qdcount)
502     {
503     if ((n = irc_dn_skipname(current, (unsigned char *)eob)) < 0)
504     break;
505    
506 michael 1124 current += (size_t)n + QFIXEDSZ;
507 adx 30 }
508    
509     /*
510 michael 4299 * Process each answer sent to us blech.
511 adx 30 */
512     while (header->ancount > 0 && (char *)current < eob)
513     {
514     header->ancount--;
515    
516     n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob, current,
517     hostbuf, sizeof(hostbuf));
518    
519 michael 4299 if (n < 0 /* Broken message */ || n == 0 /* No more answers left */)
520 michael 1124 return 0;
521 adx 30
522     hostbuf[HOSTLEN] = '\0';
523    
524 michael 4299 /*
525     * With Address arithmetic you have to be very anal
526 adx 30 * this code was not working on alpha due to that
527     * (spotted by rodder/jailbird/dianora)
528     */
529 michael 3298 current += (size_t)n;
530 adx 30
531     if (!(((char *)current + ANSWER_FIXED_SIZE) < eob))
532     break;
533    
534     type = irc_ns_get16(current);
535     current += TYPE_SIZE;
536     current += CLASS_SIZE;
537     current += TTL_SIZE;
538     rd_length = irc_ns_get16(current);
539     current += RDLENGTH_SIZE;
540    
541 michael 2916 /*
542     * Wait to set request->type until we verify this structure
543 adx 30 */
544     switch (type)
545     {
546     case T_A:
547     if (request->type != T_A)
548 michael 1124 return 0;
549 adx 30
550     /*
551 michael 3298 * Check for invalid rd_length or too many addresses
552 adx 30 */
553     if (rd_length != sizeof(struct in_addr))
554 michael 1124 return 0;
555    
556 adx 30 v4 = (struct sockaddr_in *)&request->addr;
557     request->addr.ss_len = sizeof(struct sockaddr_in);
558     v4->sin_family = AF_INET;
559     memcpy(&v4->sin_addr, current, sizeof(struct in_addr));
560 michael 1124 return 1;
561 adx 30 break;
562     #ifdef IPV6
563     case T_AAAA:
564     if (request->type != T_AAAA)
565 michael 1124 return 0;
566    
567 adx 30 if (rd_length != sizeof(struct in6_addr))
568 michael 1124 return 0;
569    
570 adx 30 request->addr.ss_len = sizeof(struct sockaddr_in6);
571     v6 = (struct sockaddr_in6 *)&request->addr;
572     v6->sin6_family = AF_INET6;
573     memcpy(&v6->sin6_addr, current, sizeof(struct in6_addr));
574 michael 1124 return 1;
575 adx 30 break;
576     #endif
577     case T_PTR:
578     if (request->type != T_PTR)
579 michael 1124 return 0;
580    
581 adx 30 n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob,
582 michael 3298 current, hostbuf, sizeof(hostbuf));
583 michael 4299 if (n < 0 /* Broken message */ || n == 0 /* No more answers left */)
584 michael 1124 return 0;
585 adx 30
586 michael 986 strlcpy(request->name, hostbuf, HOSTLEN + 1);
587 michael 1124 return 1;
588 adx 30 break;
589 michael 4299 case T_CNAME: /* First check we already haven't started looking into a cname */
590 michael 2916 if (request->type != T_PTR)
591 michael 1124 return 0;
592 adx 30
593     if (request->state == REQ_CNAME)
594     {
595     n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob,
596     current, hostbuf, sizeof(hostbuf));
597    
598     if (n < 0)
599 michael 1124 return 0;
600     return 1;
601 adx 30 }
602    
603     request->state = REQ_CNAME;
604     current += rd_length;
605     break;
606 michael 2916
607 adx 30 default:
608     /* XXX I'd rather just throw away the entire bogus thing
609     * but its possible its just a broken nameserver with still
610     * valid answers. But lets do some rudimentary logging for now...
611     */
612 michael 1247 ilog(LOG_TYPE_IRCD, "irc_res.c bogus type %d", type);
613 adx 30 break;
614     }
615     }
616    
617 michael 1124 return 1;
618 adx 30 }
619    
620     /*
621     * res_readreply - read a dns reply from the nameserver and process it.
622     */
623     static void
624     res_readreply(fde_t *fd, void *data)
625     {
626 michael 4239 char buf[sizeof(HEADER) + MAXPACKET];
627 adx 30 HEADER *header;
628     struct reslist *request = NULL;
629 michael 4302 ssize_t rc = 0;
630 adx 30 socklen_t len = sizeof(struct irc_ssaddr);
631     struct irc_ssaddr lsin;
632    
633     rc = recvfrom(fd->fd, buf, sizeof(buf), 0, (struct sockaddr *)&lsin, &len);
634    
635 michael 4312 /*
636     * Re-schedule a read *after* recvfrom, or we'll be registering
637 adx 30 * interest where it'll instantly be ready for read :-) -- adrian
638     */
639     comm_setselect(fd, COMM_SELECT_READ, res_readreply, NULL, 0);
640 michael 984
641 michael 4302 if (rc <= (ssize_t)sizeof(HEADER))
642 adx 30 return;
643    
644     /*
645 michael 4238 * Check against possibly fake replies
646     */
647     if (!res_ourserver(&lsin))
648     return;
649    
650     /*
651 michael 3298 * Convert DNS reply reader from Network byte order to CPU byte order.
652 adx 30 */
653     header = (HEADER *)buf;
654     header->ancount = ntohs(header->ancount);
655     header->qdcount = ntohs(header->qdcount);
656     header->nscount = ntohs(header->nscount);
657     header->arcount = ntohs(header->arcount);
658    
659     /*
660 michael 3298 * Response for an id which we have already received an answer for
661 michael 994 * just ignore this response.
662 adx 30 */
663 michael 4312 if ((request = find_id(header->id)) == NULL)
664 adx 30 return;
665    
666     if ((header->rcode != NO_ERRORS) || (header->ancount == 0))
667     {
668 michael 984 if (header->rcode == SERVFAIL || header->rcode == NXDOMAIN)
669 db 155 {
670 michael 984 /*
671     * If a bad error was returned, stop here and don't
672     * send any more (no retries granted).
673     */
674 michael 992 (*request->callback)(request->callback_ctx, NULL, NULL);
675 michael 984 rem_request(request);
676     }
677     #ifdef IPV6
678     else
679     {
680 michael 2916 /*
681 michael 4312 * If we havent already tried this, and we're looking up AAAA, try A now.
682 adx 30 */
683     if (request->state == REQ_AAAA && request->type == T_AAAA)
684     {
685     request->timeout += 4;
686     resend_query(request);
687     }
688 michael 984 }
689 adx 30 #endif
690 michael 984
691 db 468 return;
692 adx 30 }
693 michael 984
694 adx 30 /*
695 michael 2916 * If this fails there was an error decoding the received packet,
696 adx 30 * try it again and hope it works the next time.
697     */
698 michael 994 if (proc_answer(request, header, buf, buf + rc))
699 adx 30 {
700     if (request->type == T_PTR)
701     {
702     if (request->name == NULL)
703     {
704     /*
705 michael 3298 * Got a PTR response with no name, something bogus is happening
706 adx 30 * don't bother trying again, the client address doesn't resolve
707     */
708 michael 992 (*request->callback)(request->callback_ctx, NULL, NULL);
709 adx 30 rem_request(request);
710     return;
711     }
712    
713     /*
714 michael 3298 * Lookup the 'authoritative' name that we were given for the ip#.
715 adx 30 */
716     #ifdef IPV6
717     if (request->addr.ss.ss_family == AF_INET6)
718 michael 992 gethost_byname_type(request->callback, request->callback_ctx, request->name, T_AAAA);
719 adx 30 else
720     #endif
721 michael 992 gethost_byname_type(request->callback, request->callback_ctx, request->name, T_A);
722 adx 30 rem_request(request);
723     }
724     else
725     {
726     /*
727 michael 3298 * Got a name and address response, client resolved
728 adx 30 */
729 michael 992 (*request->callback)(request->callback_ctx, &request->addr, request->name);
730 adx 30 rem_request(request);
731     }
732     }
733     else if (!request->sent)
734     {
735     /* XXX - we got a response for a query we didn't send with a valid id?
736     * this should never happen, bail here and leave the client unresolved
737     */
738     assert(0);
739    
740 michael 4235 (*request->callback)(request->callback_ctx, NULL, NULL);
741 adx 30 /* XXX don't leak it */
742     rem_request(request);
743     }
744     }
745    
746     void
747     report_dns_servers(struct Client *source_p)
748     {
749 michael 3235 char ipaddr[HOSTIPLEN + 1] = "";
750 adx 30
751 michael 3297 for (unsigned int i = 0; i < irc_nscount; ++i)
752 adx 30 {
753 michael 1123 getnameinfo((struct sockaddr *)&(irc_nsaddr_list[i]),
754     irc_nsaddr_list[i].ss_len, ipaddr,
755     sizeof(ipaddr), NULL, 0, NI_NUMERICHOST);
756 michael 3109 sendto_one_numeric(source_p, &me, RPL_STATSALINE, ipaddr);
757 adx 30 }
758     }
759 michael 4312
760     /*
761     * timeout_query_list - Remove queries from the list which have been
762     * there too long without being resolved.
763     */
764     static time_t
765     timeout_query_list(void)
766     {
767     dlink_node *ptr = NULL, *ptr_next = NULL;
768     struct reslist *request = NULL;
769     time_t next_time = 0;
770     time_t timeout = 0;
771    
772     DLINK_FOREACH_SAFE(ptr, ptr_next, request_list.head)
773     {
774     request = ptr->data;
775     timeout = request->sentat + request->timeout;
776    
777     if (CurrentTime >= timeout)
778     {
779     if (--request->retries <= 0)
780     {
781     (*request->callback)(request->callback_ctx, NULL, NULL);
782     rem_request(request);
783     continue;
784     }
785     else
786     {
787     request->sentat = CurrentTime;
788     request->timeout += request->timeout;
789     resend_query(request);
790     }
791     }
792    
793     if (next_time == 0 || timeout < next_time)
794     next_time = timeout;
795     }
796    
797     return (next_time > CurrentTime) ? next_time : (CurrentTime + AR_TTL);
798     }
799    
800     /*
801     * timeout_resolver - check request list
802     */
803     static void
804     timeout_resolver(void *notused)
805     {
806     timeout_query_list();
807     }
808    
809     /*
810     * init_resolver - initialize resolver and resolver library
811     */
812     void
813     init_resolver(void)
814     {
815     static struct event event_timeout_resolver =
816     {
817     .name = "timeout_resolver",
818     .handler = timeout_resolver,
819     .when = 1
820     };
821    
822     dns_pool = mp_pool_new(sizeof(struct reslist), MP_CHUNK_SIZE_DNS);
823     memset(&ResolverFileDescriptor, 0, sizeof(fde_t));
824     start_resolver();
825    
826     event_add(&event_timeout_resolver, NULL);
827     }

Properties

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svn:keywords Id Revision