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root/svn/ircd-hybrid/trunk/src/res.c
Revision: 4086
Committed: Sat Jun 28 16:44:20 2014 UTC (11 years, 2 months ago) by michael
Content type: text/x-csrc
File size: 23192 byte(s)
Log Message:
- Let mp_pool_get() clear memory

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 adx 30 * 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 knight 31 * $Id$
37 adx 30 *
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 michael 2916 * All we really care about is the IP -> hostname mappings. Thats all.
44 adx 30 *
45     * Apr 28, 2003 --cryogen and Dianora
46     */
47    
48     #include "stdinc.h"
49 michael 1011 #include "list.h"
50 adx 30 #include "client.h"
51     #include "event.h"
52     #include "irc_string.h"
53     #include "ircd.h"
54     #include "numeric.h"
55 michael 982 #include "rng_mt.h"
56 adx 30 #include "fdlist.h"
57     #include "s_bsd.h"
58 michael 1309 #include "log.h"
59 michael 3347 #include "misc.h"
60 adx 30 #include "send.h"
61     #include "memory.h"
62 michael 1654 #include "mempool.h"
63 michael 3322 #include "res.h"
64     #include "reslib.h"
65 adx 30
66     #if (CHAR_BIT != 8)
67 michael 2916 #error this code needs to be able to address individual octets
68 adx 30 #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 michael 2916 typedef enum
86 adx 30 {
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 michael 985 REQ_CNAME /* We got a CNAME in response, we better get a real answer next */
94 adx 30 } request_state;
95    
96 michael 2916 struct reslist
97 adx 30 {
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 michael 3297 unsigned int sends; /* number of sends (>1 means resent) */
106 adx 30 char resend; /* send flag. 0 == dont resend */
107     time_t sentat;
108     time_t timeout;
109     struct irc_ssaddr addr;
110     char *name;
111 michael 992 dns_callback_fnc callback;
112     void *callback_ctx;
113 adx 30 };
114    
115     static fde_t ResolverFileDescriptor;
116 michael 3235 static dlink_list request_list;
117     static mp_pool_t *dns_pool;
118 adx 30
119 michael 1124 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 michael 992 const char *, struct reslist *, int);
123 michael 1124 static void do_query_number(dns_callback_fnc, void *,
124 adx 30 const struct irc_ssaddr *,
125 michael 1124 struct reslist *);
126     static void query_name(const char *, int, int, struct reslist *);
127 michael 3297 static int send_res_msg(const char *, int, unsigned int);
128 michael 1124 static void resend_query(struct reslist *);
129     static int proc_answer(struct reslist *, HEADER *, char *, char *);
130     static struct reslist *find_id(int);
131 adx 30
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 michael 2916 res_ourserver(const struct irc_ssaddr *inp)
146 adx 30 {
147     #ifdef IPV6
148 michael 992 const struct sockaddr_in6 *v6;
149     const struct sockaddr_in6 *v6in = (const struct sockaddr_in6 *)inp;
150 adx 30 #endif
151 michael 992 const struct sockaddr_in *v4;
152 michael 2916 const struct sockaddr_in *v4in = (const struct sockaddr_in *)inp;
153 adx 30
154 michael 3297 for (unsigned int i = 0; i < irc_nscount; ++i)
155 adx 30 {
156 michael 3235 const struct irc_ssaddr *srv = &irc_nsaddr_list[i];
157 adx 30 #ifdef IPV6
158 michael 992 v6 = (const struct sockaddr_in6 *)srv;
159 adx 30 #endif
160 michael 992 v4 = (const struct sockaddr_in *)srv;
161 adx 30
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 michael 1346 if (!memcmp(&v6->sin6_addr.s6_addr, &v6in->sin6_addr.s6_addr,
173     sizeof(struct in6_addr)))
174 michael 1124 return 1;
175 adx 30 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 michael 1346 if (v4->sin_addr.s_addr == v4in->sin_addr.s_addr)
181 michael 1124 return 1;
182 adx 30 break;
183     default:
184     break;
185     }
186     }
187    
188 michael 1124 return 0;
189 adx 30 }
190    
191     /*
192 michael 2916 * timeout_query_list - Remove queries from the list which have been
193 adx 30 * there too long without being resolved.
194     */
195     static time_t
196     timeout_query_list(time_t now)
197     {
198 michael 3235 dlink_node *ptr = NULL, *ptr_next = NULL;
199 adx 30 struct reslist *request;
200     time_t next_time = 0;
201     time_t timeout = 0;
202    
203 michael 3235 DLINK_FOREACH_SAFE(ptr, ptr_next, request_list.head)
204 adx 30 {
205     request = ptr->data;
206     timeout = request->sentat + request->timeout;
207    
208     if (now >= timeout)
209     {
210     if (--request->retries <= 0)
211     {
212 michael 992 (*request->callback)(request->callback_ctx, NULL, NULL);
213 adx 30 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 michael 1124 return (next_time > now) ? next_time : (now + AR_TTL);
229 adx 30 }
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 michael 3298 comm_setselect(&ResolverFileDescriptor, COMM_SELECT_READ, res_readreply, NULL, 0);
257 adx 30 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 michael 1654 dns_pool = mp_pool_new(sizeof(struct reslist), MP_CHUNK_SIZE_DNS);
268 adx 30 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 michael 3298 eventDelete(timeout_resolver, NULL);
280 adx 30 start_resolver();
281     }
282    
283     /*
284 michael 2916 * rem_request - remove a request from the list.
285     * This must also free any memory that has been allocated for
286 adx 30 * temporary storage of DNS results.
287     */
288     static void
289     rem_request(struct reslist *request)
290     {
291     dlinkDelete(&request->node, &request_list);
292 michael 998
293 adx 30 MyFree(request->name);
294 michael 1654 mp_pool_release(request);
295 adx 30 }
296    
297     /*
298     * make_request - Create a DNS request record for the server.
299     */
300     static struct reslist *
301 michael 992 make_request(dns_callback_fnc callback, void *ctx)
302 adx 30 {
303 michael 1654 struct reslist *request = mp_pool_get(dns_pool);
304 adx 30
305 michael 992 request->sentat = CurrentTime;
306 michael 3268 request->retries = 2;
307 michael 992 request->resend = 1;
308 michael 3298 request->timeout = 4; /* Start at 4 and exponential inc. */
309 michael 992 request->state = REQ_IDLE;
310     request->callback = callback;
311     request->callback_ctx = ctx;
312 adx 30
313     dlinkAdd(request, &request->node, &request_list);
314 michael 998 return request;
315 adx 30 }
316    
317     /*
318 michael 2916 * delete_resolver_queries - cleanup outstanding queries
319 adx 30 * for which there no longer exist clients or conf lines.
320     */
321     void
322 michael 992 delete_resolver_queries(const void *vptr)
323 adx 30 {
324 michael 3235 dlink_node *ptr = NULL, *ptr_next = NULL;
325 adx 30
326 michael 3235 DLINK_FOREACH_SAFE(ptr, ptr_next, request_list.head)
327 adx 30 {
328 michael 997 struct reslist *request = ptr->data;
329    
330     if (request->callback_ctx == vptr)
331     rem_request(request);
332 adx 30 }
333     }
334    
335     /*
336     * send_res_msg - sends msg to all nameservers found in the "_res" structure.
337     * This should reflect /etc/resolv.conf. We will get responses
338     * which arent needed but is easier than checking to see if nameserver
339 michael 2916 * isnt present. Returns number of messages successfully sent to
340 adx 30 * nameservers or -1 if no successful sends.
341     */
342     static int
343 michael 3297 send_res_msg(const char *msg, int len, unsigned int rcount)
344 adx 30 {
345     int sent = 0;
346 michael 3297 unsigned int max_queries = IRCD_MIN(irc_nscount, rcount);
347 adx 30
348     /* RES_PRIMARY option is not implemented
349     * if (res.options & RES_PRIMARY || 0 == max_queries)
350     */
351     if (max_queries == 0)
352     max_queries = 1;
353    
354 michael 3297 for (unsigned int i = 0; i < max_queries; ++i)
355 adx 30 {
356 michael 2916 if (sendto(ResolverFileDescriptor.fd, msg, len, 0,
357     (struct sockaddr*)&(irc_nsaddr_list[i]),
358     irc_nsaddr_list[i].ss_len) == len)
359 adx 30 ++sent;
360     }
361    
362 michael 1124 return sent;
363 adx 30 }
364    
365     /*
366     * find_id - find a dns request id (id is determined by dn_mkquery)
367     */
368     static struct reslist *
369     find_id(int id)
370     {
371 michael 1124 dlink_node *ptr = NULL;
372 adx 30
373     DLINK_FOREACH(ptr, request_list.head)
374     {
375 michael 1124 struct reslist *request = ptr->data;
376 adx 30
377     if (request->id == id)
378 michael 1124 return request;
379 adx 30 }
380    
381 michael 1124 return NULL;
382 adx 30 }
383    
384 michael 2916 /*
385 adx 30 * gethost_byname_type - get host address from name
386     *
387     */
388     void
389 michael 992 gethost_byname_type(dns_callback_fnc callback, void *ctx, const char *name, int type)
390 adx 30 {
391 michael 3235 assert(name);
392 michael 992 do_query_name(callback, ctx, name, NULL, type);
393 adx 30 }
394    
395     /*
396     * gethost_byname - wrapper for _type - send T_AAAA first if IPV6 supported
397     */
398     void
399 michael 992 gethost_byname(dns_callback_fnc callback, void *ctx, const char *name)
400 adx 30 {
401     #ifdef IPV6
402 michael 992 gethost_byname_type(callback, ctx, name, T_AAAA);
403 adx 30 #else
404 michael 992 gethost_byname_type(callback, ctx, name, T_A);
405 adx 30 #endif
406     }
407    
408     /*
409     * gethost_byaddr - get host name from address
410     */
411     void
412 michael 992 gethost_byaddr(dns_callback_fnc callback, void *ctx, const struct irc_ssaddr *addr)
413 adx 30 {
414 michael 992 do_query_number(callback, ctx, addr, NULL);
415 adx 30 }
416    
417     /*
418     * do_query_name - nameserver lookup name
419     */
420     static void
421 michael 992 do_query_name(dns_callback_fnc callback, void *ctx, const char *name,
422 adx 30 struct reslist *request, int type)
423     {
424     char host_name[HOSTLEN + 1];
425    
426 michael 998 strlcpy(host_name, name, sizeof(host_name));
427 adx 30
428     if (request == NULL)
429     {
430 michael 992 request = make_request(callback, ctx);
431 michael 3504 request->name = MyCalloc(strlen(host_name) + 1);
432 adx 30 request->type = type;
433     strcpy(request->name, host_name);
434     #ifdef IPV6
435 michael 984 if (type != T_A)
436     request->state = REQ_AAAA;
437 adx 30 else
438 michael 984 #endif
439 adx 30 request->state = REQ_A;
440     }
441    
442     request->type = type;
443     query_name(host_name, C_IN, type, request);
444     }
445    
446     /*
447     * do_query_number - Use this to do reverse IP# lookups.
448     */
449     static void
450 michael 992 do_query_number(dns_callback_fnc callback, void *ctx,
451     const struct irc_ssaddr *addr,
452 adx 30 struct reslist *request)
453     {
454 michael 3298 char ipbuf[128] = "";
455 michael 985
456 adx 30 if (addr->ss.ss_family == AF_INET)
457     {
458 michael 992 const struct sockaddr_in *v4 = (const struct sockaddr_in *)addr;
459 michael 3298 const unsigned char *cp = (const unsigned char *)&v4->sin_addr.s_addr;
460 adx 30
461 michael 1124 snprintf(ipbuf, sizeof(ipbuf), "%u.%u.%u.%u.in-addr.arpa.",
462     (unsigned int)(cp[3]), (unsigned int)(cp[2]),
463     (unsigned int)(cp[1]), (unsigned int)(cp[0]));
464 adx 30 }
465     #ifdef IPV6
466     else if (addr->ss.ss_family == AF_INET6)
467     {
468 michael 992 const struct sockaddr_in6 *v6 = (const struct sockaddr_in6 *)addr;
469 michael 3298 const unsigned char *cp = (const unsigned char *)&v6->sin6_addr.s6_addr;
470 adx 30
471 michael 1124 snprintf(ipbuf, sizeof(ipbuf),
472     "%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x."
473     "%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.ip6.arpa.",
474     (unsigned int)(cp[15] & 0xf), (unsigned int)(cp[15] >> 4),
475     (unsigned int)(cp[14] & 0xf), (unsigned int)(cp[14] >> 4),
476     (unsigned int)(cp[13] & 0xf), (unsigned int)(cp[13] >> 4),
477     (unsigned int)(cp[12] & 0xf), (unsigned int)(cp[12] >> 4),
478     (unsigned int)(cp[11] & 0xf), (unsigned int)(cp[11] >> 4),
479     (unsigned int)(cp[10] & 0xf), (unsigned int)(cp[10] >> 4),
480     (unsigned int)(cp[9] & 0xf), (unsigned int)(cp[9] >> 4),
481     (unsigned int)(cp[8] & 0xf), (unsigned int)(cp[8] >> 4),
482     (unsigned int)(cp[7] & 0xf), (unsigned int)(cp[7] >> 4),
483     (unsigned int)(cp[6] & 0xf), (unsigned int)(cp[6] >> 4),
484     (unsigned int)(cp[5] & 0xf), (unsigned int)(cp[5] >> 4),
485     (unsigned int)(cp[4] & 0xf), (unsigned int)(cp[4] >> 4),
486     (unsigned int)(cp[3] & 0xf), (unsigned int)(cp[3] >> 4),
487     (unsigned int)(cp[2] & 0xf), (unsigned int)(cp[2] >> 4),
488     (unsigned int)(cp[1] & 0xf), (unsigned int)(cp[1] >> 4),
489     (unsigned int)(cp[0] & 0xf), (unsigned int)(cp[0] >> 4));
490 adx 30 }
491     #endif
492     if (request == NULL)
493     {
494 michael 992 request = make_request(callback, ctx);
495 adx 30 request->type = T_PTR;
496     memcpy(&request->addr, addr, sizeof(struct irc_ssaddr));
497 michael 3504 request->name = MyCalloc(HOSTLEN + 1);
498 adx 30 }
499    
500     query_name(ipbuf, C_IN, T_PTR, request);
501     }
502    
503     /*
504     * query_name - generate a query based on class, type and name.
505     */
506     static void
507     query_name(const char *name, int query_class, int type,
508     struct reslist *request)
509     {
510     char buf[MAXPACKET];
511     int request_len = 0;
512    
513     memset(buf, 0, sizeof(buf));
514    
515 michael 2916 if ((request_len = irc_res_mkquery(name, query_class, type,
516 adx 30 (unsigned char *)buf, sizeof(buf))) > 0)
517     {
518     HEADER *header = (HEADER *)buf;
519 michael 982
520 adx 30 /*
521     * generate an unique id
522     * NOTE: we don't have to worry about converting this to and from
523     * network byte order, the nameserver does not interpret this value
524     * and returns it unchanged
525     */
526     do
527 michael 982 header->id = (header->id + genrand_int32()) & 0xffff;
528     while (find_id(header->id));
529    
530 adx 30 request->id = header->id;
531     ++request->sends;
532    
533     request->sent += send_res_msg(buf, request_len, request->sends);
534     }
535     }
536    
537     static void
538     resend_query(struct reslist *request)
539     {
540     if (request->resend == 0)
541     return;
542    
543 michael 982 switch (request->type)
544 adx 30 {
545     case T_PTR:
546 michael 992 do_query_number(NULL, NULL, &request->addr, request);
547 adx 30 break;
548     case T_A:
549 michael 992 do_query_name(NULL, NULL, request->name, request, request->type);
550 adx 30 break;
551     #ifdef IPV6
552     case T_AAAA:
553     /* didnt work, try A */
554     if (request->state == REQ_AAAA)
555 michael 992 do_query_name(NULL, NULL, request->name, request, T_A);
556 adx 30 #endif
557     default:
558     break;
559     }
560     }
561    
562     /*
563     * proc_answer - process name server reply
564     */
565     static int
566 michael 1124 proc_answer(struct reslist *request, HEADER *header, char *buf, char *eob)
567 adx 30 {
568     char hostbuf[HOSTLEN + 100]; /* working buffer */
569     unsigned char *current; /* current position in buf */
570     int query_class; /* answer class */
571     int type; /* answer type */
572     int n; /* temp count */
573     int rd_length;
574     struct sockaddr_in *v4; /* conversion */
575     #ifdef IPV6
576     struct sockaddr_in6 *v6;
577     #endif
578     current = (unsigned char *)buf + sizeof(HEADER);
579    
580     for (; header->qdcount > 0; --header->qdcount)
581     {
582     if ((n = irc_dn_skipname(current, (unsigned char *)eob)) < 0)
583     break;
584    
585 michael 1124 current += (size_t)n + QFIXEDSZ;
586 adx 30 }
587    
588     /*
589     * process each answer sent to us blech.
590     */
591     while (header->ancount > 0 && (char *)current < eob)
592     {
593     header->ancount--;
594    
595     n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob, current,
596     hostbuf, sizeof(hostbuf));
597    
598 michael 3298 if (n < 0 /* Broken message */ || n == 0 /* No more answers left */)
599 michael 1124 return 0;
600 adx 30
601     hostbuf[HOSTLEN] = '\0';
602    
603     /* With Address arithmetic you have to be very anal
604     * this code was not working on alpha due to that
605     * (spotted by rodder/jailbird/dianora)
606     */
607 michael 3298 current += (size_t)n;
608 adx 30
609     if (!(((char *)current + ANSWER_FIXED_SIZE) < eob))
610     break;
611    
612     type = irc_ns_get16(current);
613     current += TYPE_SIZE;
614    
615     query_class = irc_ns_get16(current);
616     current += CLASS_SIZE;
617    
618     request->ttl = irc_ns_get32(current);
619     current += TTL_SIZE;
620    
621     rd_length = irc_ns_get16(current);
622     current += RDLENGTH_SIZE;
623    
624 michael 2916 /*
625     * Wait to set request->type until we verify this structure
626 adx 30 */
627     switch (type)
628     {
629     case T_A:
630     if (request->type != T_A)
631 michael 1124 return 0;
632 adx 30
633     /*
634 michael 3298 * Check for invalid rd_length or too many addresses
635 adx 30 */
636     if (rd_length != sizeof(struct in_addr))
637 michael 1124 return 0;
638    
639 adx 30 v4 = (struct sockaddr_in *)&request->addr;
640     request->addr.ss_len = sizeof(struct sockaddr_in);
641     v4->sin_family = AF_INET;
642     memcpy(&v4->sin_addr, current, sizeof(struct in_addr));
643 michael 1124 return 1;
644 adx 30 break;
645     #ifdef IPV6
646     case T_AAAA:
647     if (request->type != T_AAAA)
648 michael 1124 return 0;
649    
650 adx 30 if (rd_length != sizeof(struct in6_addr))
651 michael 1124 return 0;
652    
653 adx 30 request->addr.ss_len = sizeof(struct sockaddr_in6);
654     v6 = (struct sockaddr_in6 *)&request->addr;
655     v6->sin6_family = AF_INET6;
656     memcpy(&v6->sin6_addr, current, sizeof(struct in6_addr));
657 michael 1124 return 1;
658 adx 30 break;
659     #endif
660     case T_PTR:
661     if (request->type != T_PTR)
662 michael 1124 return 0;
663    
664 adx 30 n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob,
665 michael 3298 current, hostbuf, sizeof(hostbuf));
666     if (n < 0 /* Broken message */ || n == 0 /* No more answers left */)
667 michael 1124 return 0;
668 adx 30
669 michael 986 strlcpy(request->name, hostbuf, HOSTLEN + 1);
670 michael 1124 return 1;
671 adx 30 break;
672 michael 2916 case T_CNAME: /* first check we already havent started looking
673 adx 30 into a cname */
674 michael 2916 if (request->type != T_PTR)
675 michael 1124 return 0;
676 adx 30
677     if (request->state == REQ_CNAME)
678     {
679     n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob,
680     current, hostbuf, sizeof(hostbuf));
681    
682     if (n < 0)
683 michael 1124 return 0;
684     return 1;
685 adx 30 }
686    
687     request->state = REQ_CNAME;
688     current += rd_length;
689     break;
690 michael 2916
691 adx 30 default:
692     /* XXX I'd rather just throw away the entire bogus thing
693     * but its possible its just a broken nameserver with still
694     * valid answers. But lets do some rudimentary logging for now...
695     */
696 michael 1247 ilog(LOG_TYPE_IRCD, "irc_res.c bogus type %d", type);
697 adx 30 break;
698     }
699     }
700    
701 michael 1124 return 1;
702 adx 30 }
703    
704     /*
705     * res_readreply - read a dns reply from the nameserver and process it.
706     */
707     static void
708     res_readreply(fde_t *fd, void *data)
709     {
710 adx 411 char buf[sizeof(HEADER) + MAXPACKET]
711 michael 2916 /* Sparc and alpha need 16bit-alignment for accessing header->id
712     * (which is uint16_t). Because of the header = (HEADER*) buf;
713 adx 411 * lateron, this is neeeded. --FaUl
714     */
715 michael 2916 #if defined(__sparc__) || defined(__alpha__)
716 adx 411 __attribute__((aligned (16)))
717 michael 2916 #endif
718 adx 411 ;
719 adx 30 HEADER *header;
720     struct reslist *request = NULL;
721     int rc;
722     socklen_t len = sizeof(struct irc_ssaddr);
723     struct irc_ssaddr lsin;
724    
725     rc = recvfrom(fd->fd, buf, sizeof(buf), 0, (struct sockaddr *)&lsin, &len);
726    
727     /* Re-schedule a read *after* recvfrom, or we'll be registering
728     * interest where it'll instantly be ready for read :-) -- adrian
729     */
730     comm_setselect(fd, COMM_SELECT_READ, res_readreply, NULL, 0);
731 michael 984
732 adx 30 /* Better to cast the sizeof instead of rc */
733     if (rc <= (int)(sizeof(HEADER)))
734     return;
735    
736     /*
737 michael 3298 * Convert DNS reply reader from Network byte order to CPU byte order.
738 adx 30 */
739     header = (HEADER *)buf;
740     header->ancount = ntohs(header->ancount);
741     header->qdcount = ntohs(header->qdcount);
742     header->nscount = ntohs(header->nscount);
743     header->arcount = ntohs(header->arcount);
744    
745     /*
746 michael 3298 * Check against possibly fake replies
747 adx 30 */
748 michael 994 if (!res_ourserver(&lsin))
749 adx 30 return;
750    
751     /*
752 michael 3298 * Response for an id which we have already received an answer for
753 michael 994 * just ignore this response.
754 adx 30 */
755 michael 994 if (!(request = find_id(header->id)))
756 adx 30 return;
757    
758     if ((header->rcode != NO_ERRORS) || (header->ancount == 0))
759     {
760 michael 984 if (header->rcode == SERVFAIL || header->rcode == NXDOMAIN)
761 db 155 {
762 michael 984 /*
763     * If a bad error was returned, stop here and don't
764     * send any more (no retries granted).
765     */
766 michael 992 (*request->callback)(request->callback_ctx, NULL, NULL);
767 michael 984 rem_request(request);
768     }
769     #ifdef IPV6
770     else
771     {
772 michael 2916 /*
773 adx 30 * If we havent already tried this, and we're looking up AAAA, try A
774     * now
775     */
776     if (request->state == REQ_AAAA && request->type == T_AAAA)
777     {
778     request->timeout += 4;
779     resend_query(request);
780     }
781 michael 984 }
782 adx 30 #endif
783 michael 984
784 db 468 return;
785 adx 30 }
786 michael 984
787 adx 30 /*
788 michael 2916 * If this fails there was an error decoding the received packet,
789 adx 30 * try it again and hope it works the next time.
790     */
791 michael 994 if (proc_answer(request, header, buf, buf + rc))
792 adx 30 {
793     if (request->type == T_PTR)
794     {
795     if (request->name == NULL)
796     {
797     /*
798 michael 3298 * Got a PTR response with no name, something bogus is happening
799 adx 30 * don't bother trying again, the client address doesn't resolve
800     */
801 michael 992 (*request->callback)(request->callback_ctx, NULL, NULL);
802 adx 30 rem_request(request);
803     return;
804     }
805    
806     /*
807 michael 3298 * Lookup the 'authoritative' name that we were given for the ip#.
808 adx 30 */
809     #ifdef IPV6
810     if (request->addr.ss.ss_family == AF_INET6)
811 michael 992 gethost_byname_type(request->callback, request->callback_ctx, request->name, T_AAAA);
812 adx 30 else
813     #endif
814 michael 992 gethost_byname_type(request->callback, request->callback_ctx, request->name, T_A);
815 adx 30 rem_request(request);
816     }
817     else
818     {
819     /*
820 michael 3298 * Got a name and address response, client resolved
821 adx 30 */
822 michael 992 (*request->callback)(request->callback_ctx, &request->addr, request->name);
823 adx 30 rem_request(request);
824     }
825     }
826     else if (!request->sent)
827     {
828     /* XXX - we got a response for a query we didn't send with a valid id?
829     * this should never happen, bail here and leave the client unresolved
830     */
831     assert(0);
832    
833     /* XXX don't leak it */
834     rem_request(request);
835     }
836     }
837    
838     void
839     report_dns_servers(struct Client *source_p)
840     {
841 michael 3235 char ipaddr[HOSTIPLEN + 1] = "";
842 adx 30
843 michael 3297 for (unsigned int i = 0; i < irc_nscount; ++i)
844 adx 30 {
845 michael 1123 getnameinfo((struct sockaddr *)&(irc_nsaddr_list[i]),
846     irc_nsaddr_list[i].ss_len, ipaddr,
847     sizeof(ipaddr), NULL, 0, NI_NUMERICHOST);
848 michael 3109 sendto_one_numeric(source_p, &me, RPL_STATSALINE, ipaddr);
849 adx 30 }
850     }

Properties

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