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 | |
7f8bbe29 | 14 | * the Free Software Foundation; either version 3, or (at your option) |
e576be50 | 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 | |
8c09a4c6 | 23 | * along with this program; if not, write to the Free Software Foundation. |
e576be50 | 24 | */ |
4353a5c4 | 25 | |
e062dcae | 26 | #include <stdlib.h> |
4353a5c4 | 27 | |
e062dcae | 28 | #include "internal.h" |
b9de380c | 29 | |
98a3f706 | 30 | void adns__procdgram(adns_state ads, const byte *dgram, int dglen, |
ebf4877a | 31 | int serv, int viatcp, struct timeval now) { |
86e7b8d9 | 32 | int cbyte, rrstart, wantedrrs, rri, foundsoa, foundns, cname_here; |
3955725c | 33 | int id, f1, f2, qdcount, ancount, nscount, arcount; |
34 | int flg_ra, flg_rd, flg_tc, flg_qr, opcode; | |
e062dcae | 35 | int rrtype, rrclass, rdlength, rdstart; |
faa52594 | 36 | int anstart, nsstart; |
88372443 | 37 | int ownermatched, l, nrrs; |
73dba56e | 38 | unsigned long ttl, soattl; |
e062dcae | 39 | const typeinfo *typei; |
98a3f706 | 40 | adns_query qu, nqu; |
41 | dns_rcode rcode; | |
b9de380c | 42 | adns_status st; |
86e7b8d9 | 43 | vbuf tempvb; |
e062dcae | 44 | byte *newquery, *rrsdata; |
1dfe95d8 | 45 | parseinfo pai; |
ec477b9e | 46 | |
98a3f706 | 47 | if (dglen<DNS_HDRSIZE) { |
609133ee | 48 | adns__diag(ads,serv,0,"received datagram" |
49 | " too short for message header (%d)",dglen); | |
ec477b9e | 50 | return; |
51 | } | |
9557e604 | 52 | cbyte= 0; |
b9de380c | 53 | GET_W(cbyte,id); |
54 | GET_B(cbyte,f1); | |
55 | GET_B(cbyte,f2); | |
56 | GET_W(cbyte,qdcount); | |
57 | GET_W(cbyte,ancount); | |
58 | GET_W(cbyte,nscount); | |
59 | GET_W(cbyte,arcount); | |
98a3f706 | 60 | assert(cbyte == DNS_HDRSIZE); |
ec477b9e | 61 | |
31144a72 | 62 | flg_qr= f1&0x80; |
63 | opcode= (f1&0x78)>>3; | |
e062dcae | 64 | flg_tc= f1&0x02; |
31144a72 | 65 | flg_rd= f1&0x01; |
0ba0614a | 66 | flg_ra= f2&0x80; |
86e7b8d9 | 67 | rcode= (f2&0x0f); |
0ba0614a | 68 | |
86e7b8d9 | 69 | cname_here= 0; |
70 | ||
9557e604 | 71 | if (!flg_qr) { |
3955725c | 72 | adns__diag(ads,serv,0,"server sent us a query, not a response"); |
ec477b9e | 73 | return; |
74 | } | |
31144a72 | 75 | if (opcode) { |
609133ee | 76 | adns__diag(ads,serv,0,"server sent us unknown opcode" |
77 | " %d (wanted 0=QUERY)",opcode); | |
ec477b9e | 78 | return; |
79 | } | |
16d7d2b5 | 80 | |
81 | qu= 0; | |
82 | /* See if we can find the relevant query, or leave qu=0 otherwise ... */ | |
83 | ||
84 | if (qdcount == 1) { | |
85 | for (qu= viatcp ? ads->tcpw.head : ads->udpw.head; qu; qu= nqu) { | |
86 | nqu= qu->next; | |
87 | if (qu->id != id) continue; | |
88 | if (dglen < qu->query_dglen) continue; | |
89 | if (memcmp(qu->query_dgram+DNS_HDRSIZE, | |
90 | dgram+DNS_HDRSIZE, | |
91 | qu->query_dglen-DNS_HDRSIZE)) | |
92 | continue; | |
93 | if (viatcp) { | |
94 | assert(qu->state == query_tcpw); | |
95 | } else { | |
96 | assert(qu->state == query_tosend); | |
97 | if (!(qu->udpsent & (1<<serv))) continue; | |
98 | } | |
99 | break; | |
ebf4877a | 100 | } |
16d7d2b5 | 101 | if (qu) { |
102 | /* We're definitely going to do something with this query now */ | |
103 | if (viatcp) LIST_UNLINK(ads->tcpw,qu); | |
104 | else LIST_UNLINK(ads->udpw,qu); | |
86e7b8d9 | 105 | } |
ec477b9e | 106 | } |
98a3f706 | 107 | |
16d7d2b5 | 108 | /* If we're going to ignore the packet, we return as soon as we have |
109 | * failed the query (if any) and printed the warning message (if | |
110 | * any). | |
111 | */ | |
b9de380c | 112 | switch (rcode) { |
113 | case rcode_noerror: | |
114 | case rcode_nxdomain: | |
ec477b9e | 115 | break; |
b9de380c | 116 | case rcode_formaterror: |
609133ee | 117 | adns__warn(ads,serv,qu,"server cannot understand our query" |
118 | " (Format Error)"); | |
16d7d2b5 | 119 | if (qu) adns__query_fail(qu,adns_s_rcodeformaterror); |
ec477b9e | 120 | return; |
98a3f706 | 121 | case rcode_servfail: |
16d7d2b5 | 122 | if (qu) adns__query_fail(qu,adns_s_rcodeservfail); |
c3ccdc54 | 123 | else adns__debug(ads,serv,qu,"server failure on unidentifiable query"); |
ec477b9e | 124 | return; |
b9de380c | 125 | case rcode_notimp: |
31144a72 | 126 | adns__warn(ads,serv,qu,"server claims not to implement our query"); |
16d7d2b5 | 127 | if (qu) adns__query_fail(qu,adns_s_rcodenotimplemented); |
b9de380c | 128 | return; |
129 | case rcode_refused: | |
d00d4b99 | 130 | adns__debug(ads,serv,qu,"server refused our query"); |
16d7d2b5 | 131 | if (qu) adns__query_fail(qu,adns_s_rcoderefused); |
b9de380c | 132 | return; |
133 | default: | |
31144a72 | 134 | adns__warn(ads,serv,qu,"server gave unknown response code %d",rcode); |
16d7d2b5 | 135 | if (qu) adns__query_fail(qu,adns_s_rcodeunknown); |
136 | return; | |
137 | } | |
138 | ||
139 | if (!qu) { | |
140 | if (!qdcount) { | |
141 | adns__diag(ads,serv,0,"server sent reply without quoting our question"); | |
142 | } else if (qdcount>1) { | |
609133ee | 143 | adns__diag(ads,serv,0,"server claimed to answer %d" |
144 | " questions with one message", qdcount); | |
16d7d2b5 | 145 | } else if (ads->iflags & adns_if_debug) { |
146 | adns__vbuf_init(&tempvb); | |
147 | adns__debug(ads,serv,0,"reply not found, id %02x, query owner %s", | |
609133ee | 148 | id, adns__diag_domain(ads,serv,0,&tempvb, |
149 | dgram,dglen,DNS_HDRSIZE)); | |
16d7d2b5 | 150 | adns__vbuf_free(&tempvb); |
151 | } | |
b9de380c | 152 | return; |
153 | } | |
154 | ||
609133ee | 155 | /* We're definitely going to do something with this packet and this |
156 | * query now. */ | |
16d7d2b5 | 157 | |
158 | anstart= qu->query_dglen; | |
16d7d2b5 | 159 | |
b9de380c | 160 | /* Now, take a look at the answer section, and see if it is complete. |
161 | * If it has any CNAMEs we stuff them in the answer. | |
162 | */ | |
163 | wantedrrs= 0; | |
86e7b8d9 | 164 | cbyte= anstart; |
b9de380c | 165 | for (rri= 0; rri<ancount; rri++) { |
166 | rrstart= cbyte; | |
3955725c | 167 | st= adns__findrr(qu,serv, dgram,dglen,&cbyte, |
73dba56e | 168 | &rrtype,&rrclass,&ttl, &rdlength,&rdstart, |
3955725c | 169 | &ownermatched); |
86e7b8d9 | 170 | if (st) { adns__query_fail(qu,st); return; } |
0ba0614a | 171 | if (rrtype == -1) goto x_truncated; |
172 | ||
b9de380c | 173 | if (rrclass != DNS_CLASS_IN) { |
609133ee | 174 | adns__diag(ads,serv,qu,"ignoring answer RR with wrong class %d" |
175 | " (expected IN=%d)", rrclass,DNS_CLASS_IN); | |
b9de380c | 176 | continue; |
177 | } | |
0ba0614a | 178 | if (!ownermatched) { |
98a3f706 | 179 | if (ads->iflags & adns_if_debug) { |
31144a72 | 180 | adns__debug(ads,serv,qu,"ignoring RR with an unexpected owner %s", |
609133ee | 181 | adns__diag_domain(ads,serv,qu, &qu->vb, |
182 | dgram,dglen,rrstart)); | |
0ba0614a | 183 | } |
b9de380c | 184 | continue; |
185 | } | |
2a6d6736 | 186 | if (rrtype == adns_r_cname && |
2c6eb096 | 187 | (qu->answer->type & adns_rrt_typemask) != adns_r_cname) { |
4b707d8b | 188 | if (qu->flags & adns_qf_cname_forbid) { |
189 | adns__query_fail(qu,adns_s_prohibitedcname); | |
190 | return; | |
636b69b1 | 191 | } else if (qu->cname_dgram) { /* Ignore second and subsequent CNAME(s) */ |
609133ee | 192 | adns__debug(ads,serv,qu,"allegedly canonical name %s" |
193 | " is actually alias for %s", qu->answer->cname, | |
194 | adns__diag_domain(ads,serv,qu, &qu->vb, | |
195 | dgram,dglen,rdstart)); | |
05db5bce | 196 | adns__query_fail(qu,adns_s_prohibitedcname); |
197 | return; | |
636b69b1 | 198 | } else if (wantedrrs) { /* Ignore CNAME(s) after RR(s). */ |
199 | adns__debug(ads,serv,qu,"ignoring CNAME (to %s) coexisting with RR", | |
609133ee | 200 | adns__diag_domain(ads,serv,qu, &qu->vb, |
201 | dgram,dglen,rdstart)); | |
636b69b1 | 202 | } else { |
31144a72 | 203 | qu->cname_begin= rdstart; |
31144a72 | 204 | qu->cname_dglen= dglen; |
828d89bd | 205 | st= adns__parse_domain(ads,serv,qu, &qu->vb, |
ac015392 | 206 | qu->flags & adns_qf_quotefail_cname |
207 | ? 0 : pdf_quoteok, | |
31144a72 | 208 | dgram,dglen, &rdstart,rdstart+rdlength); |
3955725c | 209 | if (!qu->vb.used) goto x_truncated; |
210 | if (st) { adns__query_fail(qu,st); return; } | |
211 | l= strlen(qu->vb.buf)+1; | |
8b3d55e3 | 212 | qu->answer->cname= adns__alloc_preserved(qu,l); |
609133ee | 213 | if (!qu->answer->cname) { |
214 | adns__query_fail(qu,adns_s_nomemory); | |
215 | return; | |
216 | } | |
e062dcae | 217 | |
218 | qu->cname_dgram= adns__alloc_mine(qu,dglen); | |
219 | memcpy(qu->cname_dgram,dgram,dglen); | |
220 | ||
3955725c | 221 | memcpy(qu->answer->cname,qu->vb.buf,l); |
86e7b8d9 | 222 | cname_here= 1; |
73dba56e | 223 | adns__update_expires(qu,ttl,now); |
31144a72 | 224 | /* If we find the answer section truncated after this point we restart |
225 | * the query at the CNAME; if beforehand then we obviously have to use | |
226 | * TCP. If there is no truncation we can use the whole answer if | |
227 | * it contains the relevant info. | |
228 | */ | |
31144a72 | 229 | } |
2c6eb096 | 230 | } else if (rrtype == (qu->answer->type & adns_rrt_typemask)) { |
b9de380c | 231 | wantedrrs++; |
232 | } else { | |
609133ee | 233 | adns__debug(ads,serv,qu,"ignoring answer RR" |
234 | " with irrelevant type %d",rrtype); | |
b9de380c | 235 | } |
236 | } | |
237 | ||
e062dcae | 238 | /* We defer handling truncated responses here, in case there was a CNAME |
239 | * which we could use. | |
240 | */ | |
241 | if (flg_tc) goto x_truncated; | |
242 | ||
b9de380c | 243 | nsstart= cbyte; |
244 | ||
245 | if (!wantedrrs) { | |
609133ee | 246 | /* Oops, NODATA or NXDOMAIN or perhaps a referral |
247 | * (which would be a problem) */ | |
b9de380c | 248 | |
609133ee | 249 | /* RFC2308: NODATA has _either_ a SOA _or_ _no_ NS records |
250 | * in authority section */ | |
73dba56e | 251 | foundsoa= 0; soattl= 0; foundns= 0; |
b9de380c | 252 | for (rri= 0; rri<nscount; rri++) { |
0ba0614a | 253 | rrstart= cbyte; |
3955725c | 254 | st= adns__findrr(qu,serv, dgram,dglen,&cbyte, |
73dba56e | 255 | &rrtype,&rrclass,&ttl, &rdlength,&rdstart, 0); |
3955725c | 256 | if (st) { adns__query_fail(qu,st); return; } |
0ba0614a | 257 | if (rrtype==-1) goto x_truncated; |
258 | if (rrclass != DNS_CLASS_IN) { | |
31144a72 | 259 | adns__diag(ads,serv,qu, |
609133ee | 260 | "ignoring authority RR with wrong class %d" |
261 | " (expected IN=%d)", rrclass,DNS_CLASS_IN); | |
0ba0614a | 262 | continue; |
263 | } | |
73dba56e | 264 | if (rrtype == adns_r_soa_raw) { foundsoa= 1; soattl= ttl; break; } |
0ba0614a | 265 | else if (rrtype == adns_r_ns_raw) { foundns= 1; } |
b9de380c | 266 | } |
73dba56e | 267 | |
268 | if (rcode == rcode_nxdomain) { | |
269 | /* We still wanted to look for the SOA so we could find the TTL. */ | |
270 | adns__update_expires(qu,soattl,now); | |
660d7d3b | 271 | |
ac015392 | 272 | if (qu->flags & adns_qf_search && !qu->cname_dgram) { |
660d7d3b | 273 | adns__search_next(ads,qu,now); |
274 | } else { | |
275 | adns__query_fail(qu,adns_s_nxdomain); | |
276 | } | |
73dba56e | 277 | return; |
278 | } | |
0ba0614a | 279 | |
280 | if (foundsoa || !foundns) { | |
281 | /* Aha ! A NODATA response, good. */ | |
73dba56e | 282 | adns__update_expires(qu,soattl,now); |
3955725c | 283 | adns__query_fail(qu,adns_s_nodata); |
0ba0614a | 284 | return; |
285 | } | |
286 | ||
287 | /* Now what ? No relevant answers, no SOA, and at least some NS's. | |
288 | * Looks like a referral. Just one last chance ... if we came across | |
31144a72 | 289 | * a CNAME in this datagram then we should probably do our own CNAME |
290 | * lookup now in the hope that we won't get a referral again. | |
0ba0614a | 291 | */ |
e062dcae | 292 | if (cname_here) goto x_restartquery; |
0ba0614a | 293 | |
294 | /* Bloody hell, I thought we asked for recursion ? */ | |
295 | if (!flg_ra) { | |
609133ee | 296 | adns__diag(ads,serv,qu,"server is not willing" |
297 | " to do recursive lookups for us"); | |
3955725c | 298 | adns__query_fail(qu,adns_s_norecurse); |
31144a72 | 299 | } else { |
d8ae4748 | 300 | if (!flg_rd) |
609133ee | 301 | adns__diag(ads,serv,qu,"server thinks" |
302 | " we didn't ask for recursive lookup"); | |
d8ae4748 | 303 | else |
609133ee | 304 | adns__debug(ads,serv,qu,"server claims to do recursion," |
305 | " but gave us a referral"); | |
ea1e31e3 | 306 | adns__query_fail(qu,adns_s_invalidresponse); |
0ba0614a | 307 | } |
b9de380c | 308 | return; |
309 | } | |
310 | ||
0ba0614a | 311 | /* Now, we have some RRs which we wanted. */ |
b9de380c | 312 | |
042b0909 | 313 | qu->answer->rrs.untyped= adns__alloc_interim(qu,qu->answer->rrsz*wantedrrs); |
609133ee | 314 | if (!qu->answer->rrs.untyped) { |
315 | adns__query_fail(qu,adns_s_nomemory); | |
316 | return; | |
317 | } | |
98a3f706 | 318 | |
e062dcae | 319 | typei= qu->typei; |
98a3f706 | 320 | cbyte= anstart; |
e062dcae | 321 | rrsdata= qu->answer->rrs.bytes; |
1dfe95d8 | 322 | |
323 | pai.ads= qu->ads; | |
324 | pai.qu= qu; | |
325 | pai.serv= serv; | |
326 | pai.dgram= dgram; | |
327 | pai.dglen= dglen; | |
328 | pai.nsstart= nsstart; | |
329 | pai.nscount= nscount; | |
330 | pai.arcount= arcount; | |
7da21070 | 331 | pai.now= now; |
1dfe95d8 | 332 | |
333 | for (rri=0, nrrs=0; rri<ancount; rri++) { | |
3955725c | 334 | st= adns__findrr(qu,serv, dgram,dglen,&cbyte, |
73dba56e | 335 | &rrtype,&rrclass,&ttl, &rdlength,&rdstart, |
3955725c | 336 | &ownermatched); |
98a3f706 | 337 | assert(!st); assert(rrtype != -1); |
338 | if (rrclass != DNS_CLASS_IN || | |
2c6eb096 | 339 | rrtype != (qu->answer->type & adns_rrt_typemask) || |
31144a72 | 340 | !ownermatched) |
98a3f706 | 341 | continue; |
73dba56e | 342 | adns__update_expires(qu,ttl,now); |
042b0909 MW |
343 | st= typei->parse(&pai, rdstart,rdstart+rdlength, |
344 | rrsdata+nrrs*qu->answer->rrsz); | |
3955725c | 345 | if (st) { adns__query_fail(qu,st); return; } |
31144a72 | 346 | if (rdstart==-1) goto x_truncated; |
e062dcae | 347 | nrrs++; |
98a3f706 | 348 | } |
e062dcae | 349 | assert(nrrs==wantedrrs); |
350 | qu->answer->nrrs= nrrs; | |
b9de380c | 351 | |
98a3f706 | 352 | /* This may have generated some child queries ... */ |
353 | if (qu->children.head) { | |
f7f83b4a | 354 | qu->state= query_childw; |
98a3f706 | 355 | LIST_LINK_TAIL(ads->childw,qu); |
356 | return; | |
b9de380c | 357 | } |
3955725c | 358 | adns__query_done(qu); |
98a3f706 | 359 | return; |
0ba0614a | 360 | |
e576be50 | 361 | x_truncated: |
e062dcae | 362 | |
98a3f706 | 363 | if (!flg_tc) { |
31144a72 | 364 | adns__diag(ads,serv,qu,"server sent datagram which points outside itself"); |
ea1e31e3 | 365 | adns__query_fail(qu,adns_s_invalidresponse); |
98a3f706 | 366 | return; |
367 | } | |
98a3f706 | 368 | qu->flags |= adns_qf_usevc; |
e062dcae | 369 | |
370 | x_restartquery: | |
e062dcae | 371 | if (qu->cname_dgram) { |
372 | st= adns__mkquery_frdgram(qu->ads,&qu->vb,&qu->id, | |
609133ee | 373 | qu->cname_dgram,qu->cname_dglen,qu->cname_begin, |
2c6eb096 | 374 | qu->answer->type, qu->flags); |
e062dcae | 375 | if (st) { adns__query_fail(qu,st); return; } |
376 | ||
377 | newquery= realloc(qu->query_dgram,qu->vb.used); | |
ea1e31e3 | 378 | if (!newquery) { adns__query_fail(qu,adns_s_nomemory); return; } |
e062dcae | 379 | |
380 | qu->query_dgram= newquery; | |
381 | qu->query_dglen= qu->vb.used; | |
382 | memcpy(newquery,qu->vb.buf,qu->vb.used); | |
383 | } | |
384 | ||
f7f83b4a | 385 | if (qu->state == query_tcpw) qu->state= query_tosend; |
386 | qu->retries= 0; | |
8b3d55e3 | 387 | adns__reset_preserved(qu); |
d8c062fa | 388 | adns__query_send(qu,now); |
98a3f706 | 389 | } |