Commit | Line | Data |
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e576be50 | 1 | /* |
2 | * reply.c | |
3 | * - main handling and parsing routine for received datagrams | |
4 | */ | |
5 | /* | |
ae8cc977 | 6 | * This file is part of adns, which is |
7 | * Copyright (C) 1997-2000,2003,2006 Ian Jackson | |
8 | * Copyright (C) 1999-2000,2003,2006 Tony Finch | |
9 | * Copyright (C) 1991 Massachusetts Institute of Technology | |
10 | * (See the file INSTALL for full details.) | |
e576be50 | 11 | * |
12 | * This program is free software; you can redistribute it and/or modify | |
13 | * it under the terms of the GNU General Public License as published by | |
14 | * the Free Software Foundation; either version 2, or (at your option) | |
15 | * any later version. | |
16 | * | |
17 | * This program is distributed in the hope that it will be useful, | |
18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
20 | * GNU General Public License for more details. | |
21 | * | |
22 | * You should have received a copy of the GNU General Public License | |
23 | * along with this program; if not, write to the Free Software Foundation, | |
24 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
25 | */ | |
4353a5c4 | 26 | |
e062dcae | 27 | #include <stdlib.h> |
4353a5c4 | 28 | |
e062dcae | 29 | #include "internal.h" |
b9de380c | 30 | |
98a3f706 | 31 | void adns__procdgram(adns_state ads, const byte *dgram, int dglen, |
ebf4877a | 32 | int serv, int viatcp, struct timeval now) { |
86e7b8d9 | 33 | int cbyte, rrstart, wantedrrs, rri, foundsoa, foundns, cname_here; |
3955725c | 34 | int id, f1, f2, qdcount, ancount, nscount, arcount; |
35 | int flg_ra, flg_rd, flg_tc, flg_qr, opcode; | |
e062dcae | 36 | int rrtype, rrclass, rdlength, rdstart; |
faa52594 | 37 | int anstart, nsstart; |
88372443 | 38 | int ownermatched, l, nrrs; |
73dba56e | 39 | unsigned long ttl, soattl; |
e062dcae | 40 | const typeinfo *typei; |
98a3f706 | 41 | adns_query qu, nqu; |
42 | dns_rcode rcode; | |
b9de380c | 43 | adns_status st; |
86e7b8d9 | 44 | vbuf tempvb; |
e062dcae | 45 | byte *newquery, *rrsdata; |
1dfe95d8 | 46 | parseinfo pai; |
ec477b9e | 47 | |
98a3f706 | 48 | if (dglen<DNS_HDRSIZE) { |
609133ee | 49 | adns__diag(ads,serv,0,"received datagram" |
50 | " too short for message header (%d)",dglen); | |
ec477b9e | 51 | return; |
52 | } | |
9557e604 | 53 | cbyte= 0; |
b9de380c | 54 | GET_W(cbyte,id); |
55 | GET_B(cbyte,f1); | |
56 | GET_B(cbyte,f2); | |
57 | GET_W(cbyte,qdcount); | |
58 | GET_W(cbyte,ancount); | |
59 | GET_W(cbyte,nscount); | |
60 | GET_W(cbyte,arcount); | |
98a3f706 | 61 | assert(cbyte == DNS_HDRSIZE); |
ec477b9e | 62 | |
31144a72 | 63 | flg_qr= f1&0x80; |
64 | opcode= (f1&0x78)>>3; | |
e062dcae | 65 | flg_tc= f1&0x02; |
31144a72 | 66 | flg_rd= f1&0x01; |
0ba0614a | 67 | flg_ra= f2&0x80; |
86e7b8d9 | 68 | rcode= (f2&0x0f); |
0ba0614a | 69 | |
86e7b8d9 | 70 | cname_here= 0; |
71 | ||
9557e604 | 72 | if (!flg_qr) { |
3955725c | 73 | adns__diag(ads,serv,0,"server sent us a query, not a response"); |
ec477b9e | 74 | return; |
75 | } | |
31144a72 | 76 | if (opcode) { |
609133ee | 77 | adns__diag(ads,serv,0,"server sent us unknown opcode" |
78 | " %d (wanted 0=QUERY)",opcode); | |
ec477b9e | 79 | return; |
80 | } | |
16d7d2b5 | 81 | |
82 | qu= 0; | |
83 | /* See if we can find the relevant query, or leave qu=0 otherwise ... */ | |
84 | ||
85 | if (qdcount == 1) { | |
86 | for (qu= viatcp ? ads->tcpw.head : ads->udpw.head; qu; qu= nqu) { | |
87 | nqu= qu->next; | |
88 | if (qu->id != id) continue; | |
89 | if (dglen < qu->query_dglen) continue; | |
90 | if (memcmp(qu->query_dgram+DNS_HDRSIZE, | |
91 | dgram+DNS_HDRSIZE, | |
92 | qu->query_dglen-DNS_HDRSIZE)) | |
93 | continue; | |
94 | if (viatcp) { | |
95 | assert(qu->state == query_tcpw); | |
96 | } else { | |
97 | assert(qu->state == query_tosend); | |
98 | if (!(qu->udpsent & (1<<serv))) continue; | |
99 | } | |
100 | break; | |
ebf4877a | 101 | } |
16d7d2b5 | 102 | if (qu) { |
103 | /* We're definitely going to do something with this query now */ | |
104 | if (viatcp) LIST_UNLINK(ads->tcpw,qu); | |
105 | else LIST_UNLINK(ads->udpw,qu); | |
86e7b8d9 | 106 | } |
ec477b9e | 107 | } |
98a3f706 | 108 | |
16d7d2b5 | 109 | /* If we're going to ignore the packet, we return as soon as we have |
110 | * failed the query (if any) and printed the warning message (if | |
111 | * any). | |
112 | */ | |
b9de380c | 113 | switch (rcode) { |
114 | case rcode_noerror: | |
115 | case rcode_nxdomain: | |
ec477b9e | 116 | break; |
b9de380c | 117 | case rcode_formaterror: |
609133ee | 118 | adns__warn(ads,serv,qu,"server cannot understand our query" |
119 | " (Format Error)"); | |
16d7d2b5 | 120 | if (qu) adns__query_fail(qu,adns_s_rcodeformaterror); |
ec477b9e | 121 | return; |
98a3f706 | 122 | case rcode_servfail: |
16d7d2b5 | 123 | if (qu) adns__query_fail(qu,adns_s_rcodeservfail); |
c3ccdc54 | 124 | else adns__debug(ads,serv,qu,"server failure on unidentifiable query"); |
ec477b9e | 125 | return; |
b9de380c | 126 | case rcode_notimp: |
31144a72 | 127 | adns__warn(ads,serv,qu,"server claims not to implement our query"); |
16d7d2b5 | 128 | if (qu) adns__query_fail(qu,adns_s_rcodenotimplemented); |
b9de380c | 129 | return; |
130 | case rcode_refused: | |
d00d4b99 | 131 | adns__debug(ads,serv,qu,"server refused our query"); |
16d7d2b5 | 132 | if (qu) adns__query_fail(qu,adns_s_rcoderefused); |
b9de380c | 133 | return; |
134 | default: | |
31144a72 | 135 | adns__warn(ads,serv,qu,"server gave unknown response code %d",rcode); |
16d7d2b5 | 136 | if (qu) adns__query_fail(qu,adns_s_rcodeunknown); |
137 | return; | |
138 | } | |
139 | ||
140 | if (!qu) { | |
141 | if (!qdcount) { | |
142 | adns__diag(ads,serv,0,"server sent reply without quoting our question"); | |
143 | } else if (qdcount>1) { | |
609133ee | 144 | adns__diag(ads,serv,0,"server claimed to answer %d" |
145 | " questions with one message", qdcount); | |
16d7d2b5 | 146 | } else if (ads->iflags & adns_if_debug) { |
147 | adns__vbuf_init(&tempvb); | |
148 | adns__debug(ads,serv,0,"reply not found, id %02x, query owner %s", | |
609133ee | 149 | id, adns__diag_domain(ads,serv,0,&tempvb, |
150 | dgram,dglen,DNS_HDRSIZE)); | |
16d7d2b5 | 151 | adns__vbuf_free(&tempvb); |
152 | } | |
b9de380c | 153 | return; |
154 | } | |
155 | ||
609133ee | 156 | /* We're definitely going to do something with this packet and this |
157 | * query now. */ | |
16d7d2b5 | 158 | |
159 | anstart= qu->query_dglen; | |
16d7d2b5 | 160 | |
b9de380c | 161 | /* Now, take a look at the answer section, and see if it is complete. |
162 | * If it has any CNAMEs we stuff them in the answer. | |
163 | */ | |
164 | wantedrrs= 0; | |
86e7b8d9 | 165 | cbyte= anstart; |
b9de380c | 166 | for (rri= 0; rri<ancount; rri++) { |
167 | rrstart= cbyte; | |
3955725c | 168 | st= adns__findrr(qu,serv, dgram,dglen,&cbyte, |
73dba56e | 169 | &rrtype,&rrclass,&ttl, &rdlength,&rdstart, |
3955725c | 170 | &ownermatched); |
86e7b8d9 | 171 | if (st) { adns__query_fail(qu,st); return; } |
0ba0614a | 172 | if (rrtype == -1) goto x_truncated; |
173 | ||
b9de380c | 174 | if (rrclass != DNS_CLASS_IN) { |
609133ee | 175 | adns__diag(ads,serv,qu,"ignoring answer RR with wrong class %d" |
176 | " (expected IN=%d)", rrclass,DNS_CLASS_IN); | |
b9de380c | 177 | continue; |
178 | } | |
0ba0614a | 179 | if (!ownermatched) { |
98a3f706 | 180 | if (ads->iflags & adns_if_debug) { |
31144a72 | 181 | adns__debug(ads,serv,qu,"ignoring RR with an unexpected owner %s", |
609133ee | 182 | adns__diag_domain(ads,serv,qu, &qu->vb, |
183 | dgram,dglen,rrstart)); | |
0ba0614a | 184 | } |
b9de380c | 185 | continue; |
186 | } | |
2a6d6736 | 187 | if (rrtype == adns_r_cname && |
2c6eb096 | 188 | (qu->answer->type & adns_rrt_typemask) != adns_r_cname) { |
4b707d8b | 189 | if (qu->flags & adns_qf_cname_forbid) { |
190 | adns__query_fail(qu,adns_s_prohibitedcname); | |
191 | return; | |
636b69b1 | 192 | } else if (qu->cname_dgram) { /* Ignore second and subsequent CNAME(s) */ |
609133ee | 193 | adns__debug(ads,serv,qu,"allegedly canonical name %s" |
194 | " is actually alias for %s", qu->answer->cname, | |
195 | adns__diag_domain(ads,serv,qu, &qu->vb, | |
196 | dgram,dglen,rdstart)); | |
05db5bce | 197 | adns__query_fail(qu,adns_s_prohibitedcname); |
198 | return; | |
636b69b1 | 199 | } else if (wantedrrs) { /* Ignore CNAME(s) after RR(s). */ |
200 | adns__debug(ads,serv,qu,"ignoring CNAME (to %s) coexisting with RR", | |
609133ee | 201 | adns__diag_domain(ads,serv,qu, &qu->vb, |
202 | dgram,dglen,rdstart)); | |
636b69b1 | 203 | } else { |
31144a72 | 204 | qu->cname_begin= rdstart; |
31144a72 | 205 | qu->cname_dglen= dglen; |
828d89bd | 206 | st= adns__parse_domain(ads,serv,qu, &qu->vb, |
ac015392 | 207 | qu->flags & adns_qf_quotefail_cname |
208 | ? 0 : pdf_quoteok, | |
31144a72 | 209 | dgram,dglen, &rdstart,rdstart+rdlength); |
3955725c | 210 | if (!qu->vb.used) goto x_truncated; |
211 | if (st) { adns__query_fail(qu,st); return; } | |
212 | l= strlen(qu->vb.buf)+1; | |
8b3d55e3 | 213 | qu->answer->cname= adns__alloc_preserved(qu,l); |
609133ee | 214 | if (!qu->answer->cname) { |
215 | adns__query_fail(qu,adns_s_nomemory); | |
216 | return; | |
217 | } | |
e062dcae | 218 | |
219 | qu->cname_dgram= adns__alloc_mine(qu,dglen); | |
220 | memcpy(qu->cname_dgram,dgram,dglen); | |
221 | ||
3955725c | 222 | memcpy(qu->answer->cname,qu->vb.buf,l); |
86e7b8d9 | 223 | cname_here= 1; |
73dba56e | 224 | adns__update_expires(qu,ttl,now); |
31144a72 | 225 | /* If we find the answer section truncated after this point we restart |
226 | * the query at the CNAME; if beforehand then we obviously have to use | |
227 | * TCP. If there is no truncation we can use the whole answer if | |
228 | * it contains the relevant info. | |
229 | */ | |
31144a72 | 230 | } |
2c6eb096 | 231 | } else if (rrtype == (qu->answer->type & adns_rrt_typemask)) { |
b9de380c | 232 | wantedrrs++; |
233 | } else { | |
609133ee | 234 | adns__debug(ads,serv,qu,"ignoring answer RR" |
235 | " with irrelevant type %d",rrtype); | |
b9de380c | 236 | } |
237 | } | |
238 | ||
e062dcae | 239 | /* We defer handling truncated responses here, in case there was a CNAME |
240 | * which we could use. | |
241 | */ | |
242 | if (flg_tc) goto x_truncated; | |
243 | ||
b9de380c | 244 | nsstart= cbyte; |
245 | ||
246 | if (!wantedrrs) { | |
609133ee | 247 | /* Oops, NODATA or NXDOMAIN or perhaps a referral |
248 | * (which would be a problem) */ | |
b9de380c | 249 | |
609133ee | 250 | /* RFC2308: NODATA has _either_ a SOA _or_ _no_ NS records |
251 | * in authority section */ | |
73dba56e | 252 | foundsoa= 0; soattl= 0; foundns= 0; |
b9de380c | 253 | for (rri= 0; rri<nscount; rri++) { |
0ba0614a | 254 | rrstart= cbyte; |
3955725c | 255 | st= adns__findrr(qu,serv, dgram,dglen,&cbyte, |
73dba56e | 256 | &rrtype,&rrclass,&ttl, &rdlength,&rdstart, 0); |
3955725c | 257 | if (st) { adns__query_fail(qu,st); return; } |
0ba0614a | 258 | if (rrtype==-1) goto x_truncated; |
259 | if (rrclass != DNS_CLASS_IN) { | |
31144a72 | 260 | adns__diag(ads,serv,qu, |
609133ee | 261 | "ignoring authority RR with wrong class %d" |
262 | " (expected IN=%d)", rrclass,DNS_CLASS_IN); | |
0ba0614a | 263 | continue; |
264 | } | |
73dba56e | 265 | if (rrtype == adns_r_soa_raw) { foundsoa= 1; soattl= ttl; break; } |
0ba0614a | 266 | else if (rrtype == adns_r_ns_raw) { foundns= 1; } |
b9de380c | 267 | } |
73dba56e | 268 | |
269 | if (rcode == rcode_nxdomain) { | |
270 | /* We still wanted to look for the SOA so we could find the TTL. */ | |
271 | adns__update_expires(qu,soattl,now); | |
660d7d3b | 272 | |
ac015392 | 273 | if (qu->flags & adns_qf_search && !qu->cname_dgram) { |
660d7d3b | 274 | adns__search_next(ads,qu,now); |
275 | } else { | |
276 | adns__query_fail(qu,adns_s_nxdomain); | |
277 | } | |
73dba56e | 278 | return; |
279 | } | |
0ba0614a | 280 | |
281 | if (foundsoa || !foundns) { | |
282 | /* Aha ! A NODATA response, good. */ | |
73dba56e | 283 | adns__update_expires(qu,soattl,now); |
3955725c | 284 | adns__query_fail(qu,adns_s_nodata); |
0ba0614a | 285 | return; |
286 | } | |
287 | ||
288 | /* Now what ? No relevant answers, no SOA, and at least some NS's. | |
289 | * Looks like a referral. Just one last chance ... if we came across | |
31144a72 | 290 | * a CNAME in this datagram then we should probably do our own CNAME |
291 | * lookup now in the hope that we won't get a referral again. | |
0ba0614a | 292 | */ |
e062dcae | 293 | if (cname_here) goto x_restartquery; |
0ba0614a | 294 | |
295 | /* Bloody hell, I thought we asked for recursion ? */ | |
296 | if (!flg_ra) { | |
609133ee | 297 | adns__diag(ads,serv,qu,"server is not willing" |
298 | " to do recursive lookups for us"); | |
3955725c | 299 | adns__query_fail(qu,adns_s_norecurse); |
31144a72 | 300 | } else { |
d8ae4748 | 301 | if (!flg_rd) |
609133ee | 302 | adns__diag(ads,serv,qu,"server thinks" |
303 | " we didn't ask for recursive lookup"); | |
d8ae4748 | 304 | else |
609133ee | 305 | adns__debug(ads,serv,qu,"server claims to do recursion," |
306 | " but gave us a referral"); | |
ea1e31e3 | 307 | adns__query_fail(qu,adns_s_invalidresponse); |
0ba0614a | 308 | } |
b9de380c | 309 | return; |
310 | } | |
311 | ||
0ba0614a | 312 | /* Now, we have some RRs which we wanted. */ |
b9de380c | 313 | |
b5c41613 | 314 | qu->answer->rrs.untyped= adns__alloc_interim(qu,qu->answer->rrsz*wantedrrs); |
609133ee | 315 | if (!qu->answer->rrs.untyped) { |
316 | adns__query_fail(qu,adns_s_nomemory); | |
317 | return; | |
318 | } | |
98a3f706 | 319 | |
e062dcae | 320 | typei= qu->typei; |
98a3f706 | 321 | cbyte= anstart; |
e062dcae | 322 | rrsdata= qu->answer->rrs.bytes; |
1dfe95d8 | 323 | |
324 | pai.ads= qu->ads; | |
325 | pai.qu= qu; | |
326 | pai.serv= serv; | |
327 | pai.dgram= dgram; | |
328 | pai.dglen= dglen; | |
329 | pai.nsstart= nsstart; | |
330 | pai.nscount= nscount; | |
331 | pai.arcount= arcount; | |
7da21070 | 332 | pai.now= now; |
1dfe95d8 | 333 | |
334 | for (rri=0, nrrs=0; rri<ancount; rri++) { | |
3955725c | 335 | st= adns__findrr(qu,serv, dgram,dglen,&cbyte, |
73dba56e | 336 | &rrtype,&rrclass,&ttl, &rdlength,&rdstart, |
3955725c | 337 | &ownermatched); |
98a3f706 | 338 | assert(!st); assert(rrtype != -1); |
339 | if (rrclass != DNS_CLASS_IN || | |
2c6eb096 | 340 | rrtype != (qu->answer->type & adns_rrt_typemask) || |
31144a72 | 341 | !ownermatched) |
98a3f706 | 342 | continue; |
73dba56e | 343 | adns__update_expires(qu,ttl,now); |
b5c41613 MW |
344 | st= typei->parse(&pai, rdstart,rdstart+rdlength, |
345 | rrsdata+nrrs*qu->answer->rrsz); | |
3955725c | 346 | if (st) { adns__query_fail(qu,st); return; } |
31144a72 | 347 | if (rdstart==-1) goto x_truncated; |
e062dcae | 348 | nrrs++; |
98a3f706 | 349 | } |
e062dcae | 350 | assert(nrrs==wantedrrs); |
351 | qu->answer->nrrs= nrrs; | |
b9de380c | 352 | |
98a3f706 | 353 | /* This may have generated some child queries ... */ |
354 | if (qu->children.head) { | |
f7f83b4a | 355 | qu->state= query_childw; |
98a3f706 | 356 | LIST_LINK_TAIL(ads->childw,qu); |
357 | return; | |
b9de380c | 358 | } |
3955725c | 359 | adns__query_done(qu); |
98a3f706 | 360 | return; |
0ba0614a | 361 | |
e576be50 | 362 | x_truncated: |
e062dcae | 363 | |
98a3f706 | 364 | if (!flg_tc) { |
31144a72 | 365 | adns__diag(ads,serv,qu,"server sent datagram which points outside itself"); |
ea1e31e3 | 366 | adns__query_fail(qu,adns_s_invalidresponse); |
98a3f706 | 367 | return; |
368 | } | |
98a3f706 | 369 | qu->flags |= adns_qf_usevc; |
e062dcae | 370 | |
371 | x_restartquery: | |
e062dcae | 372 | if (qu->cname_dgram) { |
373 | st= adns__mkquery_frdgram(qu->ads,&qu->vb,&qu->id, | |
609133ee | 374 | qu->cname_dgram,qu->cname_dglen,qu->cname_begin, |
2c6eb096 | 375 | qu->answer->type, qu->flags); |
e062dcae | 376 | if (st) { adns__query_fail(qu,st); return; } |
377 | ||
378 | newquery= realloc(qu->query_dgram,qu->vb.used); | |
ea1e31e3 | 379 | if (!newquery) { adns__query_fail(qu,adns_s_nomemory); return; } |
e062dcae | 380 | |
381 | qu->query_dgram= newquery; | |
382 | qu->query_dglen= qu->vb.used; | |
383 | memcpy(newquery,qu->vb.buf,qu->vb.used); | |
384 | } | |
385 | ||
f7f83b4a | 386 | if (qu->state == query_tcpw) qu->state= query_tosend; |
387 | qu->retries= 0; | |
8b3d55e3 | 388 | adns__reset_preserved(qu); |
d8c062fa | 389 | adns__query_send(qu,now); |
98a3f706 | 390 | } |