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212380e3 | 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 | * | |
42bda3f3 | 10 | * $Id: res.c 3301 2007-03-28 15:04:06Z jilles $ |
212380e3 | 11 | * from Hybrid Id: res.c 459 2006-02-12 22:21:37Z db $ |
12 | * | |
13 | * July 1999 - Rewrote a bunch of stuff here. Change hostent builder code, | |
14 | * added callbacks and reference counting of returned hostents. | |
15 | * --Bleep (Thomas Helvey <tomh@inxpress.net>) | |
16 | * | |
17 | * This was all needlessly complicated for irc. Simplified. No more hostent | |
18 | * All we really care about is the IP -> hostname mappings. Thats all. | |
19 | * | |
20 | * Apr 28, 2003 --cryogen and Dianora | |
21 | * | |
22 | * DNS server flooding lessened, AAAA-or-A lookup removed, ip6.int support | |
23 | * removed, various robustness fixes | |
24 | * | |
25 | * 2006 --jilles and nenolod | |
26 | */ | |
27 | ||
28 | #include "stdinc.h" | |
29 | #include "ircd_defs.h" | |
30 | #include "common.h" | |
31 | #include "ircd.h" | |
212380e3 | 32 | #include "res.h" |
33 | #include "reslib.h" | |
13ae2f4b | 34 | #include "match.h" |
212380e3 | 35 | #include "numeric.h" |
36 | #include "client.h" /* SNO_* */ | |
37 | ||
38 | #if (CHAR_BIT != 8) | |
39 | #error this code needs to be able to address individual octets | |
40 | #endif | |
41 | ||
42 | static PF res_readreply; | |
43 | ||
44 | #define MAXPACKET 1024 /* rfc sez 512 but we expand names so ... */ | |
45 | #define RES_MAXALIASES 35 /* maximum aliases allowed */ | |
46 | #define RES_MAXADDRS 35 /* maximum addresses allowed */ | |
47 | #define AR_TTL 600 /* TTL in seconds for dns cache entries */ | |
48 | ||
49 | /* RFC 1104/1105 wasn't very helpful about what these fields | |
50 | * should be named, so for now, we'll just name them this way. | |
51 | * we probably should look at what named calls them or something. | |
52 | */ | |
53 | #define TYPE_SIZE (size_t)2 | |
54 | #define CLASS_SIZE (size_t)2 | |
55 | #define TTL_SIZE (size_t)4 | |
56 | #define RDLENGTH_SIZE (size_t)2 | |
57 | #define ANSWER_FIXED_SIZE (TYPE_SIZE + CLASS_SIZE + TTL_SIZE + RDLENGTH_SIZE) | |
58 | ||
212380e3 | 59 | struct reslist |
60 | { | |
af81d5a0 | 61 | rb_dlink_node node; |
212380e3 | 62 | int id; |
63 | int sent; /* number of requests sent */ | |
212380e3 | 64 | time_t ttl; |
65 | char type; | |
66 | char queryname[128]; /* name currently being queried */ | |
67 | char retries; /* retry counter */ | |
68 | char sends; /* number of sends (>1 means resent) */ | |
212380e3 | 69 | time_t sentat; |
70 | time_t timeout; | |
3ea5fee7 | 71 | struct rb_sockaddr_storage addr; |
212380e3 | 72 | char *name; |
73 | struct DNSQuery *query; /* query callback for this request */ | |
74 | }; | |
75 | ||
80e150e1 | 76 | static rb_fde_t *res_fd; |
af81d5a0 | 77 | static rb_dlink_list request_list = { NULL, NULL, 0 }; |
212380e3 | 78 | |
79 | static void rem_request(struct reslist *request); | |
80 | static struct reslist *make_request(struct DNSQuery *query); | |
81 | static void do_query_name(struct DNSQuery *query, const char *name, struct reslist *request, int); | |
3ea5fee7 | 82 | static void do_query_number(struct DNSQuery *query, const struct rb_sockaddr_storage *, |
212380e3 | 83 | struct reslist *request); |
84 | static void query_name(struct reslist *request); | |
85 | static int send_res_msg(const char *buf, int len, int count); | |
86 | static void resend_query(struct reslist *request); | |
87 | static int check_question(struct reslist *request, HEADER * header, char *buf, char *eob); | |
88 | static int proc_answer(struct reslist *request, HEADER * header, char *, char *); | |
89 | static struct reslist *find_id(int id); | |
90 | static struct DNSReply *make_dnsreply(struct reslist *request); | |
91 | ||
212380e3 | 92 | /* |
93 | * int | |
94 | * res_ourserver(inp) | |
95 | * looks up "inp" in irc_nsaddr_list[] | |
96 | * returns: | |
97 | * 0 : not found | |
98 | * >0 : found | |
99 | * author: | |
100 | * paul vixie, 29may94 | |
101 | * revised for ircd, cryogen(stu) may03 | |
102 | */ | |
3ea5fee7 | 103 | static int res_ourserver(const struct rb_sockaddr_storage *inp) |
212380e3 | 104 | { |
2c2e0aa9 | 105 | #ifdef RB_IPV6 |
cda884c6 JT |
106 | const struct sockaddr_in6 *v6; |
107 | const struct sockaddr_in6 *v6in = (const struct sockaddr_in6 *)inp; | |
212380e3 | 108 | #endif |
cda884c6 JT |
109 | const struct sockaddr_in *v4; |
110 | const struct sockaddr_in *v4in = (const struct sockaddr_in *)inp; | |
212380e3 | 111 | int ns; |
112 | ||
113 | for (ns = 0; ns < irc_nscount; ns++) | |
114 | { | |
3ea5fee7 | 115 | const struct rb_sockaddr_storage *srv = &irc_nsaddr_list[ns]; |
2c2e0aa9 | 116 | #ifdef RB_IPV6 |
cda884c6 | 117 | v6 = (const struct sockaddr_in6 *)srv; |
212380e3 | 118 | #endif |
cda884c6 | 119 | v4 = (const struct sockaddr_in *)srv; |
212380e3 | 120 | |
121 | /* could probably just memcmp(srv, inp, srv.ss_len) here | |
122 | * but we'll air on the side of caution - stu | |
123 | */ | |
124 | switch (srv->ss_family) | |
125 | { | |
2c2e0aa9 | 126 | #ifdef RB_IPV6 |
212380e3 | 127 | case AF_INET6: |
128 | if (srv->ss_family == inp->ss_family) | |
129 | if (v6->sin6_port == v6in->sin6_port) | |
130 | if ((memcmp(&v6->sin6_addr.s6_addr, &v6in->sin6_addr.s6_addr, | |
131 | sizeof(struct in6_addr)) == 0) || | |
132 | (memcmp(&v6->sin6_addr.s6_addr, &in6addr_any, | |
133 | sizeof(struct in6_addr)) == 0)) | |
134 | return 1; | |
135 | break; | |
136 | #endif | |
137 | case AF_INET: | |
138 | if (srv->ss_family == inp->ss_family) | |
139 | if (v4->sin_port == v4in->sin_port) | |
140 | if ((v4->sin_addr.s_addr == INADDR_ANY) | |
141 | || (v4->sin_addr.s_addr == v4in->sin_addr.s_addr)) | |
142 | return 1; | |
143 | break; | |
144 | default: | |
145 | break; | |
146 | } | |
147 | } | |
148 | ||
149 | return 0; | |
150 | } | |
151 | ||
152 | /* | |
153 | * timeout_query_list - Remove queries from the list which have been | |
154 | * there too long without being resolved. | |
155 | */ | |
156 | static time_t timeout_query_list(time_t now) | |
157 | { | |
af81d5a0 | 158 | rb_dlink_node *ptr; |
90a3c35b | 159 | rb_dlink_node *next_ptr; |
212380e3 | 160 | struct reslist *request; |
161 | time_t next_time = 0; | |
162 | time_t timeout = 0; | |
163 | ||
90a3c35b | 164 | RB_DLINK_FOREACH_SAFE(ptr, next_ptr, request_list.head) |
212380e3 | 165 | { |
166 | request = ptr->data; | |
167 | timeout = request->sentat + request->timeout; | |
168 | ||
169 | if (now >= timeout) | |
170 | { | |
171 | if (--request->retries <= 0) | |
172 | { | |
173 | (*request->query->callback) (request->query->ptr, NULL); | |
174 | rem_request(request); | |
175 | continue; | |
176 | } | |
177 | else | |
178 | { | |
179 | request->sentat = now; | |
180 | request->timeout += request->timeout; | |
181 | resend_query(request); | |
182 | } | |
183 | } | |
184 | ||
185 | if ((next_time == 0) || timeout < next_time) | |
186 | { | |
187 | next_time = timeout; | |
188 | } | |
189 | } | |
190 | ||
191 | return (next_time > now) ? next_time : (now + AR_TTL); | |
192 | } | |
193 | ||
194 | /* | |
195 | * timeout_resolver - check request list | |
196 | */ | |
197 | static void timeout_resolver(void *notused) | |
198 | { | |
9f6bbe3c | 199 | timeout_query_list(rb_current_time()); |
212380e3 | 200 | } |
201 | ||
80e150e1 WP |
202 | static struct ev_entry *timeout_resolver_ev = NULL; |
203 | ||
212380e3 | 204 | /* |
205 | * start_resolver - do everything we need to read the resolv.conf file | |
206 | * and initialize the resolver file descriptor if needed | |
207 | */ | |
208 | static void start_resolver(void) | |
209 | { | |
210 | irc_res_init(); | |
211 | ||
cda884c6 | 212 | if (res_fd == NULL) |
212380e3 | 213 | { |
38e6acdd | 214 | if ((res_fd = rb_socket(irc_nsaddr_list[0].ss_family, SOCK_DGRAM, 0, |
80e150e1 | 215 | "UDP resolver socket")) == NULL) |
212380e3 | 216 | return; |
217 | ||
218 | /* At the moment, the resolver FD data is global .. */ | |
80e150e1 WP |
219 | rb_setselect(res_fd, RB_SELECT_READ, res_readreply, NULL); |
220 | timeout_resolver_ev = rb_event_add("timeout_resolver", timeout_resolver, NULL, 1); | |
212380e3 | 221 | } |
222 | } | |
223 | ||
224 | /* | |
225 | * init_resolver - initialize resolver and resolver library | |
226 | */ | |
227 | void init_resolver(void) | |
228 | { | |
229 | #ifdef HAVE_SRAND48 | |
9f6bbe3c | 230 | srand48(rb_current_time()); |
212380e3 | 231 | #endif |
232 | start_resolver(); | |
233 | } | |
234 | ||
235 | /* | |
236 | * restart_resolver - reread resolv.conf, reopen socket | |
237 | */ | |
238 | void restart_resolver(void) | |
239 | { | |
38e6acdd | 240 | rb_close(res_fd); |
80e150e1 WP |
241 | res_fd = NULL; |
242 | rb_event_delete(timeout_resolver_ev); /* -ddosen */ | |
212380e3 | 243 | start_resolver(); |
244 | } | |
245 | ||
246 | /* | |
247 | * add_local_domain - Add the domain to hostname, if it is missing | |
248 | * (as suggested by eps@TOASTER.SFSU.EDU) | |
249 | */ | |
250 | void add_local_domain(char *hname, size_t size) | |
251 | { | |
252 | /* try to fix up unqualified names */ | |
253 | if (strchr(hname, '.') == NULL) | |
254 | { | |
255 | if (irc_domain[0]) | |
256 | { | |
257 | size_t len = strlen(hname); | |
258 | ||
259 | if ((strlen(irc_domain) + len + 2) < size) | |
260 | { | |
261 | hname[len++] = '.'; | |
262 | strcpy(hname + len, irc_domain); | |
263 | } | |
264 | } | |
265 | } | |
266 | } | |
267 | ||
268 | /* | |
269 | * rem_request - remove a request from the list. | |
270 | * This must also free any memory that has been allocated for | |
271 | * temporary storage of DNS results. | |
272 | */ | |
273 | static void rem_request(struct reslist *request) | |
274 | { | |
af81d5a0 | 275 | rb_dlinkDelete(&request->node, &request_list); |
90a3c35b VY |
276 | rb_free(request->name); |
277 | rb_free(request); | |
212380e3 | 278 | } |
279 | ||
280 | /* | |
281 | * make_request - Create a DNS request record for the server. | |
282 | */ | |
283 | static struct reslist *make_request(struct DNSQuery *query) | |
284 | { | |
8e43b0b4 | 285 | struct reslist *request = rb_malloc(sizeof(struct reslist)); |
212380e3 | 286 | |
9f6bbe3c | 287 | request->sentat = rb_current_time(); |
212380e3 | 288 | request->retries = 3; |
212380e3 | 289 | request->timeout = 4; /* start at 4 and exponential inc. */ |
290 | request->query = query; | |
212380e3 | 291 | |
af81d5a0 | 292 | rb_dlinkAdd(request, &request->node, &request_list); |
212380e3 | 293 | |
294 | return request; | |
295 | } | |
296 | ||
297 | /* | |
298 | * delete_resolver_queries - cleanup outstanding queries | |
299 | * for which there no longer exist clients or conf lines. | |
300 | */ | |
301 | void delete_resolver_queries(const struct DNSQuery *query) | |
302 | { | |
af81d5a0 | 303 | rb_dlink_node *ptr; |
90a3c35b | 304 | rb_dlink_node *next_ptr; |
212380e3 | 305 | struct reslist *request; |
306 | ||
90a3c35b | 307 | RB_DLINK_FOREACH_SAFE(ptr, next_ptr, request_list.head) |
212380e3 | 308 | { |
309 | if ((request = ptr->data) != NULL) | |
310 | { | |
311 | if (query == request->query) | |
312 | rem_request(request); | |
313 | } | |
314 | } | |
315 | } | |
316 | ||
317 | /* | |
318 | * send_res_msg - sends msg to all nameservers found in the "_res" structure. | |
319 | * This should reflect /etc/resolv.conf. We will get responses | |
320 | * which arent needed but is easier than checking to see if nameserver | |
321 | * isnt present. Returns number of messages successfully sent to | |
322 | * nameservers or -1 if no successful sends. | |
323 | */ | |
324 | static int send_res_msg(const char *msg, int len, int rcount) | |
325 | { | |
326 | int i; | |
327 | int sent = 0; | |
328 | int max_queries = IRCD_MIN(irc_nscount, rcount); | |
329 | ||
330 | /* RES_PRIMARY option is not implemented | |
331 | * if (res.options & RES_PRIMARY || 0 == max_queries) | |
332 | */ | |
333 | if (max_queries == 0) | |
334 | max_queries = 1; | |
335 | ||
42bda3f3 | 336 | for (i = 0; sent < max_queries && i < irc_nscount; i++) |
212380e3 | 337 | { |
80e150e1 | 338 | if (sendto(rb_get_fd(res_fd), msg, len, 0, |
212380e3 | 339 | (struct sockaddr *)&(irc_nsaddr_list[i]), |
80e150e1 | 340 | GET_SS_LEN(&irc_nsaddr_list[i])) == len) |
212380e3 | 341 | ++sent; |
342 | } | |
343 | ||
344 | return (sent); | |
345 | } | |
346 | ||
347 | /* | |
348 | * find_id - find a dns request id (id is determined by dn_mkquery) | |
349 | */ | |
350 | static struct reslist *find_id(int id) | |
351 | { | |
af81d5a0 | 352 | rb_dlink_node *ptr; |
212380e3 | 353 | struct reslist *request; |
354 | ||
8e69bb4e | 355 | RB_DLINK_FOREACH(ptr, request_list.head) |
212380e3 | 356 | { |
357 | request = ptr->data; | |
358 | ||
359 | if (request->id == id) | |
360 | return (request); | |
361 | } | |
362 | ||
363 | return (NULL); | |
364 | } | |
365 | ||
366 | /* | |
367 | * gethost_byname_type - get host address from name | |
368 | * | |
369 | */ | |
370 | void gethost_byname_type(const char *name, struct DNSQuery *query, int type) | |
371 | { | |
372 | assert(name != 0); | |
373 | do_query_name(query, name, NULL, type); | |
374 | } | |
375 | ||
376 | /* | |
377 | * gethost_byaddr - get host name from address | |
378 | */ | |
3ea5fee7 | 379 | void gethost_byaddr(const struct rb_sockaddr_storage *addr, struct DNSQuery *query) |
212380e3 | 380 | { |
381 | do_query_number(query, addr, NULL); | |
382 | } | |
383 | ||
384 | /* | |
385 | * do_query_name - nameserver lookup name | |
386 | */ | |
387 | static void do_query_name(struct DNSQuery *query, const char *name, struct reslist *request, | |
388 | int type) | |
389 | { | |
390 | char host_name[HOSTLEN + 1]; | |
391 | ||
907468c4 | 392 | rb_strlcpy(host_name, name, HOSTLEN + 1); |
212380e3 | 393 | add_local_domain(host_name, HOSTLEN); |
394 | ||
395 | if (request == NULL) | |
396 | { | |
397 | request = make_request(query); | |
8e43b0b4 | 398 | request->name = (char *)rb_malloc(strlen(host_name) + 1); |
212380e3 | 399 | strcpy(request->name, host_name); |
212380e3 | 400 | } |
401 | ||
907468c4 | 402 | rb_strlcpy(request->queryname, host_name, sizeof(request->queryname)); |
212380e3 | 403 | request->type = type; |
404 | query_name(request); | |
405 | } | |
406 | ||
407 | /* | |
408 | * do_query_number - Use this to do reverse IP# lookups. | |
409 | */ | |
3ea5fee7 | 410 | static void do_query_number(struct DNSQuery *query, const struct rb_sockaddr_storage *addr, |
212380e3 | 411 | struct reslist *request) |
412 | { | |
413 | const unsigned char *cp; | |
414 | ||
415 | if (request == NULL) | |
416 | { | |
417 | request = make_request(query); | |
3ea5fee7 | 418 | memcpy(&request->addr, addr, sizeof(struct rb_sockaddr_storage)); |
8e43b0b4 | 419 | request->name = (char *)rb_malloc(HOSTLEN + 1); |
212380e3 | 420 | } |
421 | ||
422 | if (addr->ss_family == AF_INET) | |
423 | { | |
cda884c6 | 424 | const struct sockaddr_in *v4 = (const struct sockaddr_in *)addr; |
212380e3 | 425 | cp = (const unsigned char *)&v4->sin_addr.s_addr; |
426 | ||
38e6acdd | 427 | rb_sprintf(request->queryname, "%u.%u.%u.%u.in-addr.arpa", (unsigned int)(cp[3]), |
212380e3 | 428 | (unsigned int)(cp[2]), (unsigned int)(cp[1]), (unsigned int)(cp[0])); |
429 | } | |
2c2e0aa9 | 430 | #ifdef RB_IPV6 |
212380e3 | 431 | else if (addr->ss_family == AF_INET6) |
432 | { | |
cda884c6 | 433 | const struct sockaddr_in6 *v6 = (const struct sockaddr_in6 *)addr; |
212380e3 | 434 | cp = (const unsigned char *)&v6->sin6_addr.s6_addr; |
435 | ||
436 | (void)sprintf(request->queryname, "%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x." | |
437 | "%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.ip6.arpa", | |
438 | (unsigned int)(cp[15] & 0xf), (unsigned int)(cp[15] >> 4), | |
439 | (unsigned int)(cp[14] & 0xf), (unsigned int)(cp[14] >> 4), | |
440 | (unsigned int)(cp[13] & 0xf), (unsigned int)(cp[13] >> 4), | |
441 | (unsigned int)(cp[12] & 0xf), (unsigned int)(cp[12] >> 4), | |
442 | (unsigned int)(cp[11] & 0xf), (unsigned int)(cp[11] >> 4), | |
443 | (unsigned int)(cp[10] & 0xf), (unsigned int)(cp[10] >> 4), | |
444 | (unsigned int)(cp[9] & 0xf), (unsigned int)(cp[9] >> 4), | |
445 | (unsigned int)(cp[8] & 0xf), (unsigned int)(cp[8] >> 4), | |
446 | (unsigned int)(cp[7] & 0xf), (unsigned int)(cp[7] >> 4), | |
447 | (unsigned int)(cp[6] & 0xf), (unsigned int)(cp[6] >> 4), | |
448 | (unsigned int)(cp[5] & 0xf), (unsigned int)(cp[5] >> 4), | |
449 | (unsigned int)(cp[4] & 0xf), (unsigned int)(cp[4] >> 4), | |
450 | (unsigned int)(cp[3] & 0xf), (unsigned int)(cp[3] >> 4), | |
451 | (unsigned int)(cp[2] & 0xf), (unsigned int)(cp[2] >> 4), | |
452 | (unsigned int)(cp[1] & 0xf), (unsigned int)(cp[1] >> 4), | |
453 | (unsigned int)(cp[0] & 0xf), (unsigned int)(cp[0] >> 4)); | |
454 | } | |
455 | #endif | |
456 | ||
457 | request->type = T_PTR; | |
458 | query_name(request); | |
459 | } | |
460 | ||
461 | /* | |
462 | * query_name - generate a query based on class, type and name. | |
463 | */ | |
464 | static void query_name(struct reslist *request) | |
465 | { | |
466 | char buf[MAXPACKET]; | |
467 | int request_len = 0; | |
468 | ||
469 | memset(buf, 0, sizeof(buf)); | |
470 | ||
471 | if ((request_len = | |
472 | irc_res_mkquery(request->queryname, C_IN, request->type, (unsigned char *)buf, sizeof(buf))) > 0) | |
473 | { | |
474 | HEADER *header = (HEADER *) buf; | |
475 | #ifndef HAVE_LRAND48 | |
476 | int k = 0; | |
477 | struct timeval tv; | |
478 | #endif | |
479 | /* | |
480 | * generate an unique id | |
481 | * NOTE: we don't have to worry about converting this to and from | |
482 | * network byte order, the nameserver does not interpret this value | |
483 | * and returns it unchanged | |
484 | */ | |
485 | #ifdef HAVE_LRAND48 | |
486 | do | |
487 | { | |
488 | header->id = (header->id + lrand48()) & 0xffff; | |
489 | } while (find_id(header->id)); | |
490 | #else | |
491 | gettimeofday(&tv, NULL); | |
492 | do | |
493 | { | |
494 | header->id = (header->id + k + tv.tv_usec) & 0xffff; | |
495 | k++; | |
496 | } while (find_id(header->id)); | |
497 | #endif /* HAVE_LRAND48 */ | |
498 | request->id = header->id; | |
499 | ++request->sends; | |
500 | ||
501 | request->sent += send_res_msg(buf, request_len, request->sends); | |
502 | } | |
503 | } | |
504 | ||
505 | static void resend_query(struct reslist *request) | |
506 | { | |
212380e3 | 507 | switch (request->type) |
508 | { | |
509 | case T_PTR: | |
510 | do_query_number(NULL, &request->addr, request); | |
511 | break; | |
512 | case T_A: | |
2c2e0aa9 | 513 | #ifdef RB_IPV6 |
212380e3 | 514 | case T_AAAA: |
515 | #endif | |
516 | do_query_name(NULL, request->name, request, request->type); | |
517 | break; | |
518 | default: | |
519 | break; | |
520 | } | |
521 | } | |
522 | ||
523 | /* | |
524 | * check_question - check if the reply really belongs to the | |
525 | * name we queried (to guard against late replies from previous | |
526 | * queries with the same id). | |
527 | */ | |
528 | static int check_question(struct reslist *request, HEADER * header, char *buf, char *eob) | |
529 | { | |
530 | char hostbuf[128]; /* working buffer */ | |
531 | unsigned char *current; /* current position in buf */ | |
532 | int n; /* temp count */ | |
533 | ||
534 | current = (unsigned char *)buf + sizeof(HEADER); | |
535 | if (header->qdcount != 1) | |
536 | return 0; | |
537 | n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob, current, hostbuf, | |
538 | sizeof(hostbuf)); | |
539 | if (n <= 0) | |
540 | return 0; | |
541 | if (strcasecmp(hostbuf, request->queryname)) | |
542 | return 0; | |
543 | return 1; | |
544 | } | |
545 | ||
546 | /* | |
547 | * proc_answer - process name server reply | |
548 | */ | |
549 | static int proc_answer(struct reslist *request, HEADER * header, char *buf, char *eob) | |
550 | { | |
551 | char hostbuf[HOSTLEN + 100]; /* working buffer */ | |
552 | unsigned char *current; /* current position in buf */ | |
553 | int query_class; /* answer class */ | |
554 | int type; /* answer type */ | |
555 | int n; /* temp count */ | |
556 | int rd_length; | |
557 | struct sockaddr_in *v4; /* conversion */ | |
2c2e0aa9 | 558 | #ifdef RB_IPV6 |
212380e3 | 559 | struct sockaddr_in6 *v6; |
560 | #endif | |
561 | current = (unsigned char *)buf + sizeof(HEADER); | |
562 | ||
563 | for (; header->qdcount > 0; --header->qdcount) | |
564 | { | |
565 | if ((n = irc_dn_skipname(current, (unsigned char *)eob)) < 0) | |
566 | return 0; | |
567 | ||
568 | current += (size_t) n + QFIXEDSZ; | |
569 | } | |
570 | ||
571 | /* | |
572 | * process each answer sent to us blech. | |
573 | */ | |
574 | while (header->ancount > 0 && (char *)current < eob) | |
575 | { | |
576 | header->ancount--; | |
577 | ||
578 | n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob, current, hostbuf, | |
579 | sizeof(hostbuf)); | |
580 | ||
581 | if (n < 0) | |
582 | { | |
583 | /* | |
584 | * broken message | |
585 | */ | |
586 | return (0); | |
587 | } | |
588 | else if (n == 0) | |
589 | { | |
590 | /* | |
591 | * no more answers left | |
592 | */ | |
593 | return (0); | |
594 | } | |
595 | ||
596 | hostbuf[HOSTLEN] = '\0'; | |
597 | ||
598 | /* With Address arithmetic you have to be very anal | |
599 | * this code was not working on alpha due to that | |
600 | * (spotted by rodder/jailbird/dianora) | |
601 | */ | |
602 | current += (size_t) n; | |
603 | ||
604 | if (!(((char *)current + ANSWER_FIXED_SIZE) < eob)) | |
605 | break; | |
606 | ||
607 | type = irc_ns_get16(current); | |
608 | current += TYPE_SIZE; | |
609 | ||
610 | query_class = irc_ns_get16(current); | |
611 | current += CLASS_SIZE; | |
612 | ||
613 | request->ttl = irc_ns_get32(current); | |
614 | current += TTL_SIZE; | |
615 | ||
616 | rd_length = irc_ns_get16(current); | |
617 | current += RDLENGTH_SIZE; | |
618 | ||
619 | /* | |
620 | * Wait to set request->type until we verify this structure | |
621 | */ | |
622 | switch (type) | |
623 | { | |
624 | case T_A: | |
625 | if (request->type != T_A) | |
626 | return (0); | |
627 | ||
628 | /* | |
629 | * check for invalid rd_length or too many addresses | |
630 | */ | |
631 | if (rd_length != sizeof(struct in_addr)) | |
632 | return (0); | |
633 | v4 = (struct sockaddr_in *)&request->addr; | |
80e150e1 | 634 | SET_SS_LEN(&request->addr, sizeof(struct sockaddr_in)); |
212380e3 | 635 | v4->sin_family = AF_INET; |
636 | memcpy(&v4->sin_addr, current, sizeof(struct in_addr)); | |
637 | return (1); | |
638 | break; | |
2c2e0aa9 | 639 | #ifdef RB_IPV6 |
212380e3 | 640 | case T_AAAA: |
641 | if (request->type != T_AAAA) | |
642 | return (0); | |
643 | if (rd_length != sizeof(struct in6_addr)) | |
644 | return (0); | |
80e150e1 | 645 | SET_SS_LEN(&request->addr, sizeof(struct sockaddr_in6)); |
212380e3 | 646 | v6 = (struct sockaddr_in6 *)&request->addr; |
647 | v6->sin6_family = AF_INET6; | |
648 | memcpy(&v6->sin6_addr, current, sizeof(struct in6_addr)); | |
649 | return (1); | |
650 | break; | |
651 | #endif | |
652 | case T_PTR: | |
653 | if (request->type != T_PTR) | |
654 | return (0); | |
655 | n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob, current, | |
656 | hostbuf, sizeof(hostbuf)); | |
657 | if (n < 0) | |
658 | return (0); /* broken message */ | |
659 | else if (n == 0) | |
660 | return (0); /* no more answers left */ | |
661 | ||
907468c4 | 662 | rb_strlcpy(request->name, hostbuf, HOSTLEN + 1); |
212380e3 | 663 | |
664 | return (1); | |
665 | break; | |
0accfaf3 JT |
666 | case T_CNAME: |
667 | /* real answer will follow */ | |
212380e3 | 668 | current += rd_length; |
669 | break; | |
670 | ||
671 | default: | |
672 | /* XXX I'd rather just throw away the entire bogus thing | |
673 | * but its possible its just a broken nameserver with still | |
674 | * valid answers. But lets do some rudimentary logging for now... | |
675 | */ | |
676 | ilog(L_MAIN, "irc_res.c bogus type %d", type); | |
677 | break; | |
678 | } | |
679 | } | |
680 | ||
681 | return (1); | |
682 | } | |
683 | ||
684 | /* | |
685 | * res_readreply - read a dns reply from the nameserver and process it. | |
686 | */ | |
80e150e1 | 687 | static void res_readreply(rb_fde_t *F, void *data) |
212380e3 | 688 | { |
689 | char buf[sizeof(HEADER) + MAXPACKET] | |
690 | /* Sparc and alpha need 16bit-alignment for accessing header->id | |
691 | * (which is uint16_t). Because of the header = (HEADER*) buf; | |
692 | * lateron, this is neeeded. --FaUl | |
693 | */ | |
694 | #if defined(__sparc__) || defined(__alpha__) | |
695 | __attribute__ ((aligned(16))) | |
696 | #endif | |
697 | ; | |
698 | HEADER *header; | |
699 | struct reslist *request = NULL; | |
700 | struct DNSReply *reply = NULL; | |
701 | int rc; | |
702 | int answer_count; | |
3ea5fee7 VY |
703 | socklen_t len = sizeof(struct rb_sockaddr_storage); |
704 | struct rb_sockaddr_storage lsin; | |
212380e3 | 705 | |
80e150e1 | 706 | rc = recvfrom(rb_get_fd(F), buf, sizeof(buf), 0, (struct sockaddr *)&lsin, &len); |
212380e3 | 707 | |
708 | /* Re-schedule a read *after* recvfrom, or we'll be registering | |
709 | * interest where it'll instantly be ready for read :-) -- adrian | |
710 | */ | |
80e150e1 | 711 | rb_setselect(F, RB_SELECT_READ, res_readreply, NULL); |
212380e3 | 712 | /* Better to cast the sizeof instead of rc */ |
713 | if (rc <= (int)(sizeof(HEADER))) | |
714 | return; | |
715 | ||
716 | /* | |
717 | * convert DNS reply reader from Network byte order to CPU byte order. | |
718 | */ | |
719 | header = (HEADER *) buf; | |
720 | header->ancount = ntohs(header->ancount); | |
721 | header->qdcount = ntohs(header->qdcount); | |
722 | header->nscount = ntohs(header->nscount); | |
723 | header->arcount = ntohs(header->arcount); | |
724 | ||
725 | /* | |
726 | * response for an id which we have already received an answer for | |
727 | * just ignore this response. | |
728 | */ | |
729 | if (0 == (request = find_id(header->id))) | |
730 | return; | |
731 | ||
732 | /* | |
733 | * check against possibly fake replies | |
734 | */ | |
735 | if (!res_ourserver(&lsin)) | |
736 | return; | |
737 | ||
738 | if (!check_question(request, header, buf, buf + rc)) | |
739 | return; | |
740 | ||
741 | if ((header->rcode != NO_ERRORS) || (header->ancount == 0)) | |
742 | { | |
743 | if (NXDOMAIN == header->rcode) | |
744 | { | |
745 | (*request->query->callback) (request->query->ptr, NULL); | |
746 | rem_request(request); | |
747 | } | |
748 | else | |
749 | { | |
750 | /* | |
751 | * If a bad error was returned, we stop here and dont send | |
752 | * send any more (no retries granted). | |
753 | */ | |
754 | (*request->query->callback) (request->query->ptr, NULL); | |
755 | rem_request(request); | |
756 | } | |
757 | return; | |
758 | } | |
759 | /* | |
760 | * If this fails there was an error decoding the received packet, | |
761 | * give up. -- jilles | |
762 | */ | |
763 | answer_count = proc_answer(request, header, buf, buf + rc); | |
764 | ||
765 | if (answer_count) | |
766 | { | |
767 | if (request->type == T_PTR) | |
768 | { | |
769 | if (request->name == NULL) | |
770 | { | |
771 | /* | |
772 | * got a PTR response with no name, something bogus is happening | |
773 | * don't bother trying again, the client address doesn't resolve | |
774 | */ | |
775 | (*request->query->callback) (request->query->ptr, reply); | |
776 | rem_request(request); | |
777 | return; | |
778 | } | |
779 | ||
780 | /* | |
781 | * Lookup the 'authoritative' name that we were given for the | |
782 | * ip#. | |
783 | * | |
784 | */ | |
2c2e0aa9 | 785 | #ifdef RB_IPV6 |
212380e3 | 786 | if (request->addr.ss_family == AF_INET6) |
787 | gethost_byname_type(request->name, request->query, T_AAAA); | |
788 | else | |
789 | #endif | |
790 | gethost_byname_type(request->name, request->query, T_A); | |
791 | rem_request(request); | |
792 | } | |
793 | else | |
794 | { | |
795 | /* | |
796 | * got a name and address response, client resolved | |
797 | */ | |
798 | reply = make_dnsreply(request); | |
799 | (*request->query->callback) (request->query->ptr, reply); | |
90a3c35b | 800 | rb_free(reply); |
212380e3 | 801 | rem_request(request); |
802 | } | |
803 | } | |
804 | else | |
805 | { | |
806 | /* couldn't decode, give up -- jilles */ | |
807 | (*request->query->callback) (request->query->ptr, NULL); | |
808 | rem_request(request); | |
809 | } | |
810 | } | |
811 | ||
812 | static struct DNSReply *make_dnsreply(struct reslist *request) | |
813 | { | |
814 | struct DNSReply *cp; | |
815 | s_assert(request != 0); | |
816 | ||
8e43b0b4 | 817 | cp = (struct DNSReply *)rb_malloc(sizeof(struct DNSReply)); |
212380e3 | 818 | |
819 | cp->h_name = request->name; | |
820 | memcpy(&cp->addr, &request->addr, sizeof(cp->addr)); | |
821 | return (cp); | |
822 | } | |
823 | ||
824 | void report_dns_servers(struct Client *source_p) | |
825 | { | |
826 | int i; | |
827 | char ipaddr[128]; | |
828 | ||
829 | for (i = 0; i < irc_nscount; i++) | |
830 | { | |
9879cd59 | 831 | if (!rb_inet_ntop_sock((struct sockaddr *)&(irc_nsaddr_list[i]), |
212380e3 | 832 | ipaddr, sizeof ipaddr)) |
907468c4 | 833 | rb_strlcpy(ipaddr, "?", sizeof ipaddr); |
212380e3 | 834 | sendto_one_numeric(source_p, RPL_STATSDEBUG, |
835 | "A %s", ipaddr); | |
836 | } | |
837 | } |