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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 | ||
59 | typedef enum | |
60 | { | |
61 | REQ_IDLE, /* We're doing not much at all */ | |
62 | REQ_PTR, /* Looking up a PTR */ | |
63 | REQ_A, /* Looking up an A or AAAA */ | |
64 | REQ_CNAME /* We got a CNAME in response, we better get a real answer next */ | |
65 | } request_state; | |
66 | ||
67 | struct reslist | |
68 | { | |
af81d5a0 | 69 | rb_dlink_node node; |
212380e3 | 70 | int id; |
71 | int sent; /* number of requests sent */ | |
72 | request_state state; /* State the resolver machine is in */ | |
73 | time_t ttl; | |
74 | char type; | |
75 | char queryname[128]; /* name currently being queried */ | |
76 | char retries; /* retry counter */ | |
77 | char sends; /* number of sends (>1 means resent) */ | |
78 | char resend; /* send flag. 0 == dont resend */ | |
79 | time_t sentat; | |
80 | time_t timeout; | |
3ea5fee7 | 81 | struct rb_sockaddr_storage addr; |
212380e3 | 82 | char *name; |
83 | struct DNSQuery *query; /* query callback for this request */ | |
84 | }; | |
85 | ||
80e150e1 | 86 | static rb_fde_t *res_fd; |
af81d5a0 | 87 | static rb_dlink_list request_list = { NULL, NULL, 0 }; |
212380e3 | 88 | |
89 | static void rem_request(struct reslist *request); | |
90 | static struct reslist *make_request(struct DNSQuery *query); | |
91 | static void do_query_name(struct DNSQuery *query, const char *name, struct reslist *request, int); | |
3ea5fee7 | 92 | static void do_query_number(struct DNSQuery *query, const struct rb_sockaddr_storage *, |
212380e3 | 93 | struct reslist *request); |
94 | static void query_name(struct reslist *request); | |
95 | static int send_res_msg(const char *buf, int len, int count); | |
96 | static void resend_query(struct reslist *request); | |
97 | static int check_question(struct reslist *request, HEADER * header, char *buf, char *eob); | |
98 | static int proc_answer(struct reslist *request, HEADER * header, char *, char *); | |
99 | static struct reslist *find_id(int id); | |
100 | static struct DNSReply *make_dnsreply(struct reslist *request); | |
101 | ||
3ea5fee7 | 102 | extern struct rb_sockaddr_storage irc_nsaddr_list[IRCD_MAXNS]; |
212380e3 | 103 | extern int irc_nscount; |
104 | extern char irc_domain[HOSTLEN + 1]; | |
105 | ||
106 | ||
107 | /* | |
108 | * int | |
109 | * res_ourserver(inp) | |
110 | * looks up "inp" in irc_nsaddr_list[] | |
111 | * returns: | |
112 | * 0 : not found | |
113 | * >0 : found | |
114 | * author: | |
115 | * paul vixie, 29may94 | |
116 | * revised for ircd, cryogen(stu) may03 | |
117 | */ | |
3ea5fee7 | 118 | static int res_ourserver(const struct rb_sockaddr_storage *inp) |
212380e3 | 119 | { |
2c2e0aa9 | 120 | #ifdef RB_IPV6 |
cda884c6 JT |
121 | const struct sockaddr_in6 *v6; |
122 | const struct sockaddr_in6 *v6in = (const struct sockaddr_in6 *)inp; | |
212380e3 | 123 | #endif |
cda884c6 JT |
124 | const struct sockaddr_in *v4; |
125 | const struct sockaddr_in *v4in = (const struct sockaddr_in *)inp; | |
212380e3 | 126 | int ns; |
127 | ||
128 | for (ns = 0; ns < irc_nscount; ns++) | |
129 | { | |
3ea5fee7 | 130 | const struct rb_sockaddr_storage *srv = &irc_nsaddr_list[ns]; |
2c2e0aa9 | 131 | #ifdef RB_IPV6 |
cda884c6 | 132 | v6 = (const struct sockaddr_in6 *)srv; |
212380e3 | 133 | #endif |
cda884c6 | 134 | v4 = (const struct sockaddr_in *)srv; |
212380e3 | 135 | |
136 | /* could probably just memcmp(srv, inp, srv.ss_len) here | |
137 | * but we'll air on the side of caution - stu | |
138 | */ | |
139 | switch (srv->ss_family) | |
140 | { | |
2c2e0aa9 | 141 | #ifdef RB_IPV6 |
212380e3 | 142 | case AF_INET6: |
143 | if (srv->ss_family == inp->ss_family) | |
144 | if (v6->sin6_port == v6in->sin6_port) | |
145 | if ((memcmp(&v6->sin6_addr.s6_addr, &v6in->sin6_addr.s6_addr, | |
146 | sizeof(struct in6_addr)) == 0) || | |
147 | (memcmp(&v6->sin6_addr.s6_addr, &in6addr_any, | |
148 | sizeof(struct in6_addr)) == 0)) | |
149 | return 1; | |
150 | break; | |
151 | #endif | |
152 | case AF_INET: | |
153 | if (srv->ss_family == inp->ss_family) | |
154 | if (v4->sin_port == v4in->sin_port) | |
155 | if ((v4->sin_addr.s_addr == INADDR_ANY) | |
156 | || (v4->sin_addr.s_addr == v4in->sin_addr.s_addr)) | |
157 | return 1; | |
158 | break; | |
159 | default: | |
160 | break; | |
161 | } | |
162 | } | |
163 | ||
164 | return 0; | |
165 | } | |
166 | ||
167 | /* | |
168 | * timeout_query_list - Remove queries from the list which have been | |
169 | * there too long without being resolved. | |
170 | */ | |
171 | static time_t timeout_query_list(time_t now) | |
172 | { | |
af81d5a0 | 173 | rb_dlink_node *ptr; |
90a3c35b | 174 | rb_dlink_node *next_ptr; |
212380e3 | 175 | struct reslist *request; |
176 | time_t next_time = 0; | |
177 | time_t timeout = 0; | |
178 | ||
90a3c35b | 179 | RB_DLINK_FOREACH_SAFE(ptr, next_ptr, request_list.head) |
212380e3 | 180 | { |
181 | request = ptr->data; | |
182 | timeout = request->sentat + request->timeout; | |
183 | ||
184 | if (now >= timeout) | |
185 | { | |
186 | if (--request->retries <= 0) | |
187 | { | |
188 | (*request->query->callback) (request->query->ptr, NULL); | |
189 | rem_request(request); | |
190 | continue; | |
191 | } | |
192 | else | |
193 | { | |
194 | request->sentat = now; | |
195 | request->timeout += request->timeout; | |
196 | resend_query(request); | |
197 | } | |
198 | } | |
199 | ||
200 | if ((next_time == 0) || timeout < next_time) | |
201 | { | |
202 | next_time = timeout; | |
203 | } | |
204 | } | |
205 | ||
206 | return (next_time > now) ? next_time : (now + AR_TTL); | |
207 | } | |
208 | ||
209 | /* | |
210 | * timeout_resolver - check request list | |
211 | */ | |
212 | static void timeout_resolver(void *notused) | |
213 | { | |
9f6bbe3c | 214 | timeout_query_list(rb_current_time()); |
212380e3 | 215 | } |
216 | ||
80e150e1 WP |
217 | static struct ev_entry *timeout_resolver_ev = NULL; |
218 | ||
212380e3 | 219 | /* |
220 | * start_resolver - do everything we need to read the resolv.conf file | |
221 | * and initialize the resolver file descriptor if needed | |
222 | */ | |
223 | static void start_resolver(void) | |
224 | { | |
225 | irc_res_init(); | |
226 | ||
cda884c6 | 227 | if (res_fd == NULL) |
212380e3 | 228 | { |
38e6acdd | 229 | if ((res_fd = rb_socket(irc_nsaddr_list[0].ss_family, SOCK_DGRAM, 0, |
80e150e1 | 230 | "UDP resolver socket")) == NULL) |
212380e3 | 231 | return; |
232 | ||
233 | /* At the moment, the resolver FD data is global .. */ | |
80e150e1 WP |
234 | rb_setselect(res_fd, RB_SELECT_READ, res_readreply, NULL); |
235 | timeout_resolver_ev = rb_event_add("timeout_resolver", timeout_resolver, NULL, 1); | |
212380e3 | 236 | } |
237 | } | |
238 | ||
239 | /* | |
240 | * init_resolver - initialize resolver and resolver library | |
241 | */ | |
242 | void init_resolver(void) | |
243 | { | |
244 | #ifdef HAVE_SRAND48 | |
9f6bbe3c | 245 | srand48(rb_current_time()); |
212380e3 | 246 | #endif |
247 | start_resolver(); | |
248 | } | |
249 | ||
250 | /* | |
251 | * restart_resolver - reread resolv.conf, reopen socket | |
252 | */ | |
253 | void restart_resolver(void) | |
254 | { | |
38e6acdd | 255 | rb_close(res_fd); |
80e150e1 WP |
256 | res_fd = NULL; |
257 | rb_event_delete(timeout_resolver_ev); /* -ddosen */ | |
212380e3 | 258 | start_resolver(); |
259 | } | |
260 | ||
261 | /* | |
262 | * add_local_domain - Add the domain to hostname, if it is missing | |
263 | * (as suggested by eps@TOASTER.SFSU.EDU) | |
264 | */ | |
265 | void add_local_domain(char *hname, size_t size) | |
266 | { | |
267 | /* try to fix up unqualified names */ | |
268 | if (strchr(hname, '.') == NULL) | |
269 | { | |
270 | if (irc_domain[0]) | |
271 | { | |
272 | size_t len = strlen(hname); | |
273 | ||
274 | if ((strlen(irc_domain) + len + 2) < size) | |
275 | { | |
276 | hname[len++] = '.'; | |
277 | strcpy(hname + len, irc_domain); | |
278 | } | |
279 | } | |
280 | } | |
281 | } | |
282 | ||
283 | /* | |
284 | * rem_request - remove a request from the list. | |
285 | * This must also free any memory that has been allocated for | |
286 | * temporary storage of DNS results. | |
287 | */ | |
288 | static void rem_request(struct reslist *request) | |
289 | { | |
af81d5a0 | 290 | rb_dlinkDelete(&request->node, &request_list); |
90a3c35b VY |
291 | rb_free(request->name); |
292 | rb_free(request); | |
212380e3 | 293 | } |
294 | ||
295 | /* | |
296 | * make_request - Create a DNS request record for the server. | |
297 | */ | |
298 | static struct reslist *make_request(struct DNSQuery *query) | |
299 | { | |
8e43b0b4 | 300 | struct reslist *request = rb_malloc(sizeof(struct reslist)); |
212380e3 | 301 | |
9f6bbe3c | 302 | request->sentat = rb_current_time(); |
212380e3 | 303 | request->retries = 3; |
304 | request->resend = 1; | |
305 | request->timeout = 4; /* start at 4 and exponential inc. */ | |
306 | request->query = query; | |
307 | request->state = REQ_IDLE; | |
308 | ||
af81d5a0 | 309 | rb_dlinkAdd(request, &request->node, &request_list); |
212380e3 | 310 | |
311 | return request; | |
312 | } | |
313 | ||
314 | /* | |
315 | * delete_resolver_queries - cleanup outstanding queries | |
316 | * for which there no longer exist clients or conf lines. | |
317 | */ | |
318 | void delete_resolver_queries(const struct DNSQuery *query) | |
319 | { | |
af81d5a0 | 320 | rb_dlink_node *ptr; |
90a3c35b | 321 | rb_dlink_node *next_ptr; |
212380e3 | 322 | struct reslist *request; |
323 | ||
90a3c35b | 324 | RB_DLINK_FOREACH_SAFE(ptr, next_ptr, request_list.head) |
212380e3 | 325 | { |
326 | if ((request = ptr->data) != NULL) | |
327 | { | |
328 | if (query == request->query) | |
329 | rem_request(request); | |
330 | } | |
331 | } | |
332 | } | |
333 | ||
334 | /* | |
335 | * send_res_msg - sends msg to all nameservers found in the "_res" structure. | |
336 | * This should reflect /etc/resolv.conf. We will get responses | |
337 | * which arent needed but is easier than checking to see if nameserver | |
338 | * isnt present. Returns number of messages successfully sent to | |
339 | * nameservers or -1 if no successful sends. | |
340 | */ | |
341 | static int send_res_msg(const char *msg, int len, int rcount) | |
342 | { | |
343 | int i; | |
344 | int sent = 0; | |
345 | int max_queries = IRCD_MIN(irc_nscount, rcount); | |
346 | ||
347 | /* RES_PRIMARY option is not implemented | |
348 | * if (res.options & RES_PRIMARY || 0 == max_queries) | |
349 | */ | |
350 | if (max_queries == 0) | |
351 | max_queries = 1; | |
352 | ||
42bda3f3 | 353 | for (i = 0; sent < max_queries && i < irc_nscount; i++) |
212380e3 | 354 | { |
80e150e1 | 355 | if (sendto(rb_get_fd(res_fd), msg, len, 0, |
212380e3 | 356 | (struct sockaddr *)&(irc_nsaddr_list[i]), |
80e150e1 | 357 | GET_SS_LEN(&irc_nsaddr_list[i])) == len) |
212380e3 | 358 | ++sent; |
359 | } | |
360 | ||
361 | return (sent); | |
362 | } | |
363 | ||
364 | /* | |
365 | * find_id - find a dns request id (id is determined by dn_mkquery) | |
366 | */ | |
367 | static struct reslist *find_id(int id) | |
368 | { | |
af81d5a0 | 369 | rb_dlink_node *ptr; |
212380e3 | 370 | struct reslist *request; |
371 | ||
8e69bb4e | 372 | RB_DLINK_FOREACH(ptr, request_list.head) |
212380e3 | 373 | { |
374 | request = ptr->data; | |
375 | ||
376 | if (request->id == id) | |
377 | return (request); | |
378 | } | |
379 | ||
380 | return (NULL); | |
381 | } | |
382 | ||
383 | /* | |
384 | * gethost_byname_type - get host address from name | |
385 | * | |
386 | */ | |
387 | void gethost_byname_type(const char *name, struct DNSQuery *query, int type) | |
388 | { | |
389 | assert(name != 0); | |
390 | do_query_name(query, name, NULL, type); | |
391 | } | |
392 | ||
393 | /* | |
394 | * gethost_byaddr - get host name from address | |
395 | */ | |
3ea5fee7 | 396 | void gethost_byaddr(const struct rb_sockaddr_storage *addr, struct DNSQuery *query) |
212380e3 | 397 | { |
398 | do_query_number(query, addr, NULL); | |
399 | } | |
400 | ||
401 | /* | |
402 | * do_query_name - nameserver lookup name | |
403 | */ | |
404 | static void do_query_name(struct DNSQuery *query, const char *name, struct reslist *request, | |
405 | int type) | |
406 | { | |
407 | char host_name[HOSTLEN + 1]; | |
408 | ||
907468c4 | 409 | rb_strlcpy(host_name, name, HOSTLEN + 1); |
212380e3 | 410 | add_local_domain(host_name, HOSTLEN); |
411 | ||
412 | if (request == NULL) | |
413 | { | |
414 | request = make_request(query); | |
8e43b0b4 | 415 | request->name = (char *)rb_malloc(strlen(host_name) + 1); |
212380e3 | 416 | strcpy(request->name, host_name); |
417 | request->state = REQ_A; | |
418 | } | |
419 | ||
907468c4 | 420 | rb_strlcpy(request->queryname, host_name, sizeof(request->queryname)); |
212380e3 | 421 | request->type = type; |
422 | query_name(request); | |
423 | } | |
424 | ||
425 | /* | |
426 | * do_query_number - Use this to do reverse IP# lookups. | |
427 | */ | |
3ea5fee7 | 428 | static void do_query_number(struct DNSQuery *query, const struct rb_sockaddr_storage *addr, |
212380e3 | 429 | struct reslist *request) |
430 | { | |
431 | const unsigned char *cp; | |
432 | ||
433 | if (request == NULL) | |
434 | { | |
435 | request = make_request(query); | |
3ea5fee7 | 436 | memcpy(&request->addr, addr, sizeof(struct rb_sockaddr_storage)); |
8e43b0b4 | 437 | request->name = (char *)rb_malloc(HOSTLEN + 1); |
212380e3 | 438 | } |
439 | ||
440 | if (addr->ss_family == AF_INET) | |
441 | { | |
cda884c6 | 442 | const struct sockaddr_in *v4 = (const struct sockaddr_in *)addr; |
212380e3 | 443 | cp = (const unsigned char *)&v4->sin_addr.s_addr; |
444 | ||
38e6acdd | 445 | rb_sprintf(request->queryname, "%u.%u.%u.%u.in-addr.arpa", (unsigned int)(cp[3]), |
212380e3 | 446 | (unsigned int)(cp[2]), (unsigned int)(cp[1]), (unsigned int)(cp[0])); |
447 | } | |
2c2e0aa9 | 448 | #ifdef RB_IPV6 |
212380e3 | 449 | else if (addr->ss_family == AF_INET6) |
450 | { | |
cda884c6 | 451 | const struct sockaddr_in6 *v6 = (const struct sockaddr_in6 *)addr; |
212380e3 | 452 | cp = (const unsigned char *)&v6->sin6_addr.s6_addr; |
453 | ||
454 | (void)sprintf(request->queryname, "%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x." | |
455 | "%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.ip6.arpa", | |
456 | (unsigned int)(cp[15] & 0xf), (unsigned int)(cp[15] >> 4), | |
457 | (unsigned int)(cp[14] & 0xf), (unsigned int)(cp[14] >> 4), | |
458 | (unsigned int)(cp[13] & 0xf), (unsigned int)(cp[13] >> 4), | |
459 | (unsigned int)(cp[12] & 0xf), (unsigned int)(cp[12] >> 4), | |
460 | (unsigned int)(cp[11] & 0xf), (unsigned int)(cp[11] >> 4), | |
461 | (unsigned int)(cp[10] & 0xf), (unsigned int)(cp[10] >> 4), | |
462 | (unsigned int)(cp[9] & 0xf), (unsigned int)(cp[9] >> 4), | |
463 | (unsigned int)(cp[8] & 0xf), (unsigned int)(cp[8] >> 4), | |
464 | (unsigned int)(cp[7] & 0xf), (unsigned int)(cp[7] >> 4), | |
465 | (unsigned int)(cp[6] & 0xf), (unsigned int)(cp[6] >> 4), | |
466 | (unsigned int)(cp[5] & 0xf), (unsigned int)(cp[5] >> 4), | |
467 | (unsigned int)(cp[4] & 0xf), (unsigned int)(cp[4] >> 4), | |
468 | (unsigned int)(cp[3] & 0xf), (unsigned int)(cp[3] >> 4), | |
469 | (unsigned int)(cp[2] & 0xf), (unsigned int)(cp[2] >> 4), | |
470 | (unsigned int)(cp[1] & 0xf), (unsigned int)(cp[1] >> 4), | |
471 | (unsigned int)(cp[0] & 0xf), (unsigned int)(cp[0] >> 4)); | |
472 | } | |
473 | #endif | |
474 | ||
475 | request->type = T_PTR; | |
476 | query_name(request); | |
477 | } | |
478 | ||
479 | /* | |
480 | * query_name - generate a query based on class, type and name. | |
481 | */ | |
482 | static void query_name(struct reslist *request) | |
483 | { | |
484 | char buf[MAXPACKET]; | |
485 | int request_len = 0; | |
486 | ||
487 | memset(buf, 0, sizeof(buf)); | |
488 | ||
489 | if ((request_len = | |
490 | irc_res_mkquery(request->queryname, C_IN, request->type, (unsigned char *)buf, sizeof(buf))) > 0) | |
491 | { | |
492 | HEADER *header = (HEADER *) buf; | |
493 | #ifndef HAVE_LRAND48 | |
494 | int k = 0; | |
495 | struct timeval tv; | |
496 | #endif | |
497 | /* | |
498 | * generate an unique id | |
499 | * NOTE: we don't have to worry about converting this to and from | |
500 | * network byte order, the nameserver does not interpret this value | |
501 | * and returns it unchanged | |
502 | */ | |
503 | #ifdef HAVE_LRAND48 | |
504 | do | |
505 | { | |
506 | header->id = (header->id + lrand48()) & 0xffff; | |
507 | } while (find_id(header->id)); | |
508 | #else | |
509 | gettimeofday(&tv, NULL); | |
510 | do | |
511 | { | |
512 | header->id = (header->id + k + tv.tv_usec) & 0xffff; | |
513 | k++; | |
514 | } while (find_id(header->id)); | |
515 | #endif /* HAVE_LRAND48 */ | |
516 | request->id = header->id; | |
517 | ++request->sends; | |
518 | ||
519 | request->sent += send_res_msg(buf, request_len, request->sends); | |
520 | } | |
521 | } | |
522 | ||
523 | static void resend_query(struct reslist *request) | |
524 | { | |
525 | if (request->resend == 0) | |
526 | return; | |
527 | ||
528 | switch (request->type) | |
529 | { | |
530 | case T_PTR: | |
531 | do_query_number(NULL, &request->addr, request); | |
532 | break; | |
533 | case T_A: | |
2c2e0aa9 | 534 | #ifdef RB_IPV6 |
212380e3 | 535 | case T_AAAA: |
536 | #endif | |
537 | do_query_name(NULL, request->name, request, request->type); | |
538 | break; | |
539 | default: | |
540 | break; | |
541 | } | |
542 | } | |
543 | ||
544 | /* | |
545 | * check_question - check if the reply really belongs to the | |
546 | * name we queried (to guard against late replies from previous | |
547 | * queries with the same id). | |
548 | */ | |
549 | static int check_question(struct reslist *request, HEADER * header, char *buf, char *eob) | |
550 | { | |
551 | char hostbuf[128]; /* working buffer */ | |
552 | unsigned char *current; /* current position in buf */ | |
553 | int n; /* temp count */ | |
554 | ||
555 | current = (unsigned char *)buf + sizeof(HEADER); | |
556 | if (header->qdcount != 1) | |
557 | return 0; | |
558 | n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob, current, hostbuf, | |
559 | sizeof(hostbuf)); | |
560 | if (n <= 0) | |
561 | return 0; | |
562 | if (strcasecmp(hostbuf, request->queryname)) | |
563 | return 0; | |
564 | return 1; | |
565 | } | |
566 | ||
567 | /* | |
568 | * proc_answer - process name server reply | |
569 | */ | |
570 | static int proc_answer(struct reslist *request, HEADER * header, char *buf, char *eob) | |
571 | { | |
572 | char hostbuf[HOSTLEN + 100]; /* working buffer */ | |
573 | unsigned char *current; /* current position in buf */ | |
574 | int query_class; /* answer class */ | |
575 | int type; /* answer type */ | |
576 | int n; /* temp count */ | |
577 | int rd_length; | |
578 | struct sockaddr_in *v4; /* conversion */ | |
2c2e0aa9 | 579 | #ifdef RB_IPV6 |
212380e3 | 580 | struct sockaddr_in6 *v6; |
581 | #endif | |
582 | current = (unsigned char *)buf + sizeof(HEADER); | |
583 | ||
584 | for (; header->qdcount > 0; --header->qdcount) | |
585 | { | |
586 | if ((n = irc_dn_skipname(current, (unsigned char *)eob)) < 0) | |
587 | return 0; | |
588 | ||
589 | current += (size_t) n + QFIXEDSZ; | |
590 | } | |
591 | ||
592 | /* | |
593 | * process each answer sent to us blech. | |
594 | */ | |
595 | while (header->ancount > 0 && (char *)current < eob) | |
596 | { | |
597 | header->ancount--; | |
598 | ||
599 | n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob, current, hostbuf, | |
600 | sizeof(hostbuf)); | |
601 | ||
602 | if (n < 0) | |
603 | { | |
604 | /* | |
605 | * broken message | |
606 | */ | |
607 | return (0); | |
608 | } | |
609 | else if (n == 0) | |
610 | { | |
611 | /* | |
612 | * no more answers left | |
613 | */ | |
614 | return (0); | |
615 | } | |
616 | ||
617 | hostbuf[HOSTLEN] = '\0'; | |
618 | ||
619 | /* With Address arithmetic you have to be very anal | |
620 | * this code was not working on alpha due to that | |
621 | * (spotted by rodder/jailbird/dianora) | |
622 | */ | |
623 | current += (size_t) n; | |
624 | ||
625 | if (!(((char *)current + ANSWER_FIXED_SIZE) < eob)) | |
626 | break; | |
627 | ||
628 | type = irc_ns_get16(current); | |
629 | current += TYPE_SIZE; | |
630 | ||
631 | query_class = irc_ns_get16(current); | |
632 | current += CLASS_SIZE; | |
633 | ||
634 | request->ttl = irc_ns_get32(current); | |
635 | current += TTL_SIZE; | |
636 | ||
637 | rd_length = irc_ns_get16(current); | |
638 | current += RDLENGTH_SIZE; | |
639 | ||
640 | /* | |
641 | * Wait to set request->type until we verify this structure | |
642 | */ | |
643 | switch (type) | |
644 | { | |
645 | case T_A: | |
646 | if (request->type != T_A) | |
647 | return (0); | |
648 | ||
649 | /* | |
650 | * check for invalid rd_length or too many addresses | |
651 | */ | |
652 | if (rd_length != sizeof(struct in_addr)) | |
653 | return (0); | |
654 | v4 = (struct sockaddr_in *)&request->addr; | |
80e150e1 | 655 | SET_SS_LEN(&request->addr, sizeof(struct sockaddr_in)); |
212380e3 | 656 | v4->sin_family = AF_INET; |
657 | memcpy(&v4->sin_addr, current, sizeof(struct in_addr)); | |
658 | return (1); | |
659 | break; | |
2c2e0aa9 | 660 | #ifdef RB_IPV6 |
212380e3 | 661 | case T_AAAA: |
662 | if (request->type != T_AAAA) | |
663 | return (0); | |
664 | if (rd_length != sizeof(struct in6_addr)) | |
665 | return (0); | |
80e150e1 | 666 | SET_SS_LEN(&request->addr, sizeof(struct sockaddr_in6)); |
212380e3 | 667 | v6 = (struct sockaddr_in6 *)&request->addr; |
668 | v6->sin6_family = AF_INET6; | |
669 | memcpy(&v6->sin6_addr, current, sizeof(struct in6_addr)); | |
670 | return (1); | |
671 | break; | |
672 | #endif | |
673 | case T_PTR: | |
674 | if (request->type != T_PTR) | |
675 | return (0); | |
676 | n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob, current, | |
677 | hostbuf, sizeof(hostbuf)); | |
678 | if (n < 0) | |
679 | return (0); /* broken message */ | |
680 | else if (n == 0) | |
681 | return (0); /* no more answers left */ | |
682 | ||
907468c4 | 683 | rb_strlcpy(request->name, hostbuf, HOSTLEN + 1); |
212380e3 | 684 | |
685 | return (1); | |
686 | break; | |
687 | case T_CNAME: /* first check we already havent started looking | |
688 | into a cname */ | |
689 | if (request->type != T_PTR) | |
690 | return (0); | |
691 | ||
692 | if (request->state == REQ_CNAME) | |
693 | { | |
694 | n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob, | |
695 | current, hostbuf, sizeof(hostbuf)); | |
696 | ||
697 | if (n < 0) | |
698 | return (0); | |
699 | return (1); | |
700 | } | |
701 | ||
702 | request->state = REQ_CNAME; | |
703 | current += rd_length; | |
704 | break; | |
705 | ||
706 | default: | |
707 | /* XXX I'd rather just throw away the entire bogus thing | |
708 | * but its possible its just a broken nameserver with still | |
709 | * valid answers. But lets do some rudimentary logging for now... | |
710 | */ | |
711 | ilog(L_MAIN, "irc_res.c bogus type %d", type); | |
712 | break; | |
713 | } | |
714 | } | |
715 | ||
716 | return (1); | |
717 | } | |
718 | ||
719 | /* | |
720 | * res_readreply - read a dns reply from the nameserver and process it. | |
721 | */ | |
80e150e1 | 722 | static void res_readreply(rb_fde_t *F, void *data) |
212380e3 | 723 | { |
724 | char buf[sizeof(HEADER) + MAXPACKET] | |
725 | /* Sparc and alpha need 16bit-alignment for accessing header->id | |
726 | * (which is uint16_t). Because of the header = (HEADER*) buf; | |
727 | * lateron, this is neeeded. --FaUl | |
728 | */ | |
729 | #if defined(__sparc__) || defined(__alpha__) | |
730 | __attribute__ ((aligned(16))) | |
731 | #endif | |
732 | ; | |
733 | HEADER *header; | |
734 | struct reslist *request = NULL; | |
735 | struct DNSReply *reply = NULL; | |
736 | int rc; | |
737 | int answer_count; | |
3ea5fee7 VY |
738 | socklen_t len = sizeof(struct rb_sockaddr_storage); |
739 | struct rb_sockaddr_storage lsin; | |
212380e3 | 740 | |
80e150e1 | 741 | rc = recvfrom(rb_get_fd(F), buf, sizeof(buf), 0, (struct sockaddr *)&lsin, &len); |
212380e3 | 742 | |
743 | /* Re-schedule a read *after* recvfrom, or we'll be registering | |
744 | * interest where it'll instantly be ready for read :-) -- adrian | |
745 | */ | |
80e150e1 | 746 | rb_setselect(F, RB_SELECT_READ, res_readreply, NULL); |
212380e3 | 747 | /* Better to cast the sizeof instead of rc */ |
748 | if (rc <= (int)(sizeof(HEADER))) | |
749 | return; | |
750 | ||
751 | /* | |
752 | * convert DNS reply reader from Network byte order to CPU byte order. | |
753 | */ | |
754 | header = (HEADER *) buf; | |
755 | header->ancount = ntohs(header->ancount); | |
756 | header->qdcount = ntohs(header->qdcount); | |
757 | header->nscount = ntohs(header->nscount); | |
758 | header->arcount = ntohs(header->arcount); | |
759 | ||
760 | /* | |
761 | * response for an id which we have already received an answer for | |
762 | * just ignore this response. | |
763 | */ | |
764 | if (0 == (request = find_id(header->id))) | |
765 | return; | |
766 | ||
767 | /* | |
768 | * check against possibly fake replies | |
769 | */ | |
770 | if (!res_ourserver(&lsin)) | |
771 | return; | |
772 | ||
773 | if (!check_question(request, header, buf, buf + rc)) | |
774 | return; | |
775 | ||
776 | if ((header->rcode != NO_ERRORS) || (header->ancount == 0)) | |
777 | { | |
778 | if (NXDOMAIN == header->rcode) | |
779 | { | |
780 | (*request->query->callback) (request->query->ptr, NULL); | |
781 | rem_request(request); | |
782 | } | |
783 | else | |
784 | { | |
785 | /* | |
786 | * If a bad error was returned, we stop here and dont send | |
787 | * send any more (no retries granted). | |
788 | */ | |
789 | (*request->query->callback) (request->query->ptr, NULL); | |
790 | rem_request(request); | |
791 | } | |
792 | return; | |
793 | } | |
794 | /* | |
795 | * If this fails there was an error decoding the received packet, | |
796 | * give up. -- jilles | |
797 | */ | |
798 | answer_count = proc_answer(request, header, buf, buf + rc); | |
799 | ||
800 | if (answer_count) | |
801 | { | |
802 | if (request->type == T_PTR) | |
803 | { | |
804 | if (request->name == NULL) | |
805 | { | |
806 | /* | |
807 | * got a PTR response with no name, something bogus is happening | |
808 | * don't bother trying again, the client address doesn't resolve | |
809 | */ | |
810 | (*request->query->callback) (request->query->ptr, reply); | |
811 | rem_request(request); | |
812 | return; | |
813 | } | |
814 | ||
815 | /* | |
816 | * Lookup the 'authoritative' name that we were given for the | |
817 | * ip#. | |
818 | * | |
819 | */ | |
2c2e0aa9 | 820 | #ifdef RB_IPV6 |
212380e3 | 821 | if (request->addr.ss_family == AF_INET6) |
822 | gethost_byname_type(request->name, request->query, T_AAAA); | |
823 | else | |
824 | #endif | |
825 | gethost_byname_type(request->name, request->query, T_A); | |
826 | rem_request(request); | |
827 | } | |
828 | else | |
829 | { | |
830 | /* | |
831 | * got a name and address response, client resolved | |
832 | */ | |
833 | reply = make_dnsreply(request); | |
834 | (*request->query->callback) (request->query->ptr, reply); | |
90a3c35b | 835 | rb_free(reply); |
212380e3 | 836 | rem_request(request); |
837 | } | |
838 | } | |
839 | else | |
840 | { | |
841 | /* couldn't decode, give up -- jilles */ | |
842 | (*request->query->callback) (request->query->ptr, NULL); | |
843 | rem_request(request); | |
844 | } | |
845 | } | |
846 | ||
847 | static struct DNSReply *make_dnsreply(struct reslist *request) | |
848 | { | |
849 | struct DNSReply *cp; | |
850 | s_assert(request != 0); | |
851 | ||
8e43b0b4 | 852 | cp = (struct DNSReply *)rb_malloc(sizeof(struct DNSReply)); |
212380e3 | 853 | |
854 | cp->h_name = request->name; | |
855 | memcpy(&cp->addr, &request->addr, sizeof(cp->addr)); | |
856 | return (cp); | |
857 | } | |
858 | ||
859 | void report_dns_servers(struct Client *source_p) | |
860 | { | |
861 | int i; | |
862 | char ipaddr[128]; | |
863 | ||
864 | for (i = 0; i < irc_nscount; i++) | |
865 | { | |
9879cd59 | 866 | if (!rb_inet_ntop_sock((struct sockaddr *)&(irc_nsaddr_list[i]), |
212380e3 | 867 | ipaddr, sizeof ipaddr)) |
907468c4 | 868 | rb_strlcpy(ipaddr, "?", sizeof ipaddr); |
212380e3 | 869 | sendto_one_numeric(source_p, RPL_STATSDEBUG, |
870 | "A %s", ipaddr); | |
871 | } | |
872 | } |