Commit | Line | Data |
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98db6da3 | 1 | /* |
2 | * reply.c | |
3 | * - main handling and parsing routine for received datagrams | |
4 | */ | |
5 | /* | |
39f45e7e | 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.) | |
98db6da3 | 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 | */ | |
d05cc330 | 26 | |
f2ad23ee | 27 | #include <stdlib.h> |
d05cc330 | 28 | |
f2ad23ee | 29 | #include "internal.h" |
54ed1d64 | 30 | |
5c596e4d | 31 | void adns__procdgram(adns_state ads, const byte *dgram, int dglen, |
c84b7355 | 32 | int serv, int viatcp, struct timeval now) { |
1e9efa71 | 33 | int cbyte, rrstart, wantedrrs, rri, foundsoa, foundns, cname_here; |
11c8bf9b | 34 | int id, f1, f2, qdcount, ancount, nscount, arcount; |
35 | int flg_ra, flg_rd, flg_tc, flg_qr, opcode; | |
f2ad23ee | 36 | int rrtype, rrclass, rdlength, rdstart; |
5c596e4d | 37 | int anstart, nsstart, arstart; |
f318f883 | 38 | int ownermatched, l, nrrs; |
2c7b101b | 39 | unsigned long ttl, soattl; |
f2ad23ee | 40 | const typeinfo *typei; |
5c596e4d | 41 | adns_query qu, nqu; |
42 | dns_rcode rcode; | |
54ed1d64 | 43 | adns_status st; |
1e9efa71 | 44 | vbuf tempvb; |
f2ad23ee | 45 | byte *newquery, *rrsdata; |
26eb6bdc | 46 | parseinfo pai; |
168e26fe | 47 | |
5c596e4d | 48 | if (dglen<DNS_HDRSIZE) { |
9c344a42 | 49 | adns__diag(ads,serv,0,"received datagram" |
50 | " too short for message header (%d)",dglen); | |
168e26fe | 51 | return; |
52 | } | |
9a2b67d4 | 53 | cbyte= 0; |
54ed1d64 | 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); | |
5c596e4d | 61 | assert(cbyte == DNS_HDRSIZE); |
168e26fe | 62 | |
7f702335 | 63 | flg_qr= f1&0x80; |
64 | opcode= (f1&0x78)>>3; | |
f2ad23ee | 65 | flg_tc= f1&0x02; |
7f702335 | 66 | flg_rd= f1&0x01; |
8312a1c2 | 67 | flg_ra= f2&0x80; |
1e9efa71 | 68 | rcode= (f2&0x0f); |
8312a1c2 | 69 | |
1e9efa71 | 70 | cname_here= 0; |
71 | ||
9a2b67d4 | 72 | if (!flg_qr) { |
11c8bf9b | 73 | adns__diag(ads,serv,0,"server sent us a query, not a response"); |
168e26fe | 74 | return; |
75 | } | |
7f702335 | 76 | if (opcode) { |
9c344a42 | 77 | adns__diag(ads,serv,0,"server sent us unknown opcode" |
78 | " %d (wanted 0=QUERY)",opcode); | |
168e26fe | 79 | return; |
80 | } | |
47eed012 | 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; | |
c84b7355 | 101 | } |
47eed012 | 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); | |
1e9efa71 | 106 | } |
168e26fe | 107 | } |
5c596e4d | 108 | |
47eed012 | 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 | */ | |
54ed1d64 | 113 | switch (rcode) { |
114 | case rcode_noerror: | |
115 | case rcode_nxdomain: | |
168e26fe | 116 | break; |
54ed1d64 | 117 | case rcode_formaterror: |
9c344a42 | 118 | adns__warn(ads,serv,qu,"server cannot understand our query" |
119 | " (Format Error)"); | |
47eed012 | 120 | if (qu) adns__query_fail(qu,adns_s_rcodeformaterror); |
168e26fe | 121 | return; |
5c596e4d | 122 | case rcode_servfail: |
47eed012 | 123 | if (qu) adns__query_fail(qu,adns_s_rcodeservfail); |
ebb95bff | 124 | else adns__debug(ads,serv,qu,"server failure on unidentifiable query"); |
168e26fe | 125 | return; |
54ed1d64 | 126 | case rcode_notimp: |
7f702335 | 127 | adns__warn(ads,serv,qu,"server claims not to implement our query"); |
47eed012 | 128 | if (qu) adns__query_fail(qu,adns_s_rcodenotimplemented); |
54ed1d64 | 129 | return; |
130 | case rcode_refused: | |
6064dcef | 131 | adns__debug(ads,serv,qu,"server refused our query"); |
47eed012 | 132 | if (qu) adns__query_fail(qu,adns_s_rcoderefused); |
54ed1d64 | 133 | return; |
134 | default: | |
7f702335 | 135 | adns__warn(ads,serv,qu,"server gave unknown response code %d",rcode); |
47eed012 | 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) { | |
9c344a42 | 144 | adns__diag(ads,serv,0,"server claimed to answer %d" |
145 | " questions with one message", qdcount); | |
47eed012 | 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", | |
9c344a42 | 149 | id, adns__diag_domain(ads,serv,0,&tempvb, |
150 | dgram,dglen,DNS_HDRSIZE)); | |
47eed012 | 151 | adns__vbuf_free(&tempvb); |
152 | } | |
54ed1d64 | 153 | return; |
154 | } | |
155 | ||
9c344a42 | 156 | /* We're definitely going to do something with this packet and this |
157 | * query now. */ | |
47eed012 | 158 | |
159 | anstart= qu->query_dglen; | |
160 | arstart= -1; | |
161 | ||
54ed1d64 | 162 | /* Now, take a look at the answer section, and see if it is complete. |
163 | * If it has any CNAMEs we stuff them in the answer. | |
164 | */ | |
165 | wantedrrs= 0; | |
1e9efa71 | 166 | cbyte= anstart; |
54ed1d64 | 167 | for (rri= 0; rri<ancount; rri++) { |
168 | rrstart= cbyte; | |
11c8bf9b | 169 | st= adns__findrr(qu,serv, dgram,dglen,&cbyte, |
2c7b101b | 170 | &rrtype,&rrclass,&ttl, &rdlength,&rdstart, |
11c8bf9b | 171 | &ownermatched); |
1e9efa71 | 172 | if (st) { adns__query_fail(qu,st); return; } |
8312a1c2 | 173 | if (rrtype == -1) goto x_truncated; |
174 | ||
54ed1d64 | 175 | if (rrclass != DNS_CLASS_IN) { |
9c344a42 | 176 | adns__diag(ads,serv,qu,"ignoring answer RR with wrong class %d" |
177 | " (expected IN=%d)", rrclass,DNS_CLASS_IN); | |
54ed1d64 | 178 | continue; |
179 | } | |
8312a1c2 | 180 | if (!ownermatched) { |
5c596e4d | 181 | if (ads->iflags & adns_if_debug) { |
7f702335 | 182 | adns__debug(ads,serv,qu,"ignoring RR with an unexpected owner %s", |
9c344a42 | 183 | adns__diag_domain(ads,serv,qu, &qu->vb, |
184 | dgram,dglen,rrstart)); | |
8312a1c2 | 185 | } |
54ed1d64 | 186 | continue; |
187 | } | |
940c3875 | 188 | if (rrtype == adns_r_cname && |
7d0aaee4 | 189 | (qu->answer->type & adns_rrt_typemask) != adns_r_cname) { |
59fbb06a | 190 | if (qu->flags & adns_qf_cname_forbid) { |
191 | adns__query_fail(qu,adns_s_prohibitedcname); | |
192 | return; | |
125de2a9 | 193 | } else if (qu->cname_dgram) { /* Ignore second and subsequent CNAME(s) */ |
9c344a42 | 194 | adns__debug(ads,serv,qu,"allegedly canonical name %s" |
195 | " is actually alias for %s", qu->answer->cname, | |
196 | adns__diag_domain(ads,serv,qu, &qu->vb, | |
197 | dgram,dglen,rdstart)); | |
9dbde8ca | 198 | adns__query_fail(qu,adns_s_prohibitedcname); |
199 | return; | |
125de2a9 | 200 | } else if (wantedrrs) { /* Ignore CNAME(s) after RR(s). */ |
201 | adns__debug(ads,serv,qu,"ignoring CNAME (to %s) coexisting with RR", | |
9c344a42 | 202 | adns__diag_domain(ads,serv,qu, &qu->vb, |
203 | dgram,dglen,rdstart)); | |
125de2a9 | 204 | } else { |
7f702335 | 205 | qu->cname_begin= rdstart; |
7f702335 | 206 | qu->cname_dglen= dglen; |
cd363ffd | 207 | st= adns__parse_domain(ads,serv,qu, &qu->vb, |
85021e18 | 208 | qu->flags & adns_qf_quotefail_cname |
209 | ? 0 : pdf_quoteok, | |
7f702335 | 210 | dgram,dglen, &rdstart,rdstart+rdlength); |
11c8bf9b | 211 | if (!qu->vb.used) goto x_truncated; |
212 | if (st) { adns__query_fail(qu,st); return; } | |
213 | l= strlen(qu->vb.buf)+1; | |
1be24aef | 214 | qu->answer->cname= adns__alloc_preserved(qu,l); |
9c344a42 | 215 | if (!qu->answer->cname) { |
216 | adns__query_fail(qu,adns_s_nomemory); | |
217 | return; | |
218 | } | |
f2ad23ee | 219 | |
220 | qu->cname_dgram= adns__alloc_mine(qu,dglen); | |
221 | memcpy(qu->cname_dgram,dgram,dglen); | |
222 | ||
11c8bf9b | 223 | memcpy(qu->answer->cname,qu->vb.buf,l); |
1e9efa71 | 224 | cname_here= 1; |
2c7b101b | 225 | adns__update_expires(qu,ttl,now); |
7f702335 | 226 | /* If we find the answer section truncated after this point we restart |
227 | * the query at the CNAME; if beforehand then we obviously have to use | |
228 | * TCP. If there is no truncation we can use the whole answer if | |
229 | * it contains the relevant info. | |
230 | */ | |
7f702335 | 231 | } |
7d0aaee4 | 232 | } else if (rrtype == (qu->answer->type & adns_rrt_typemask)) { |
54ed1d64 | 233 | wantedrrs++; |
234 | } else { | |
9c344a42 | 235 | adns__debug(ads,serv,qu,"ignoring answer RR" |
236 | " with irrelevant type %d",rrtype); | |
54ed1d64 | 237 | } |
238 | } | |
239 | ||
f2ad23ee | 240 | /* We defer handling truncated responses here, in case there was a CNAME |
241 | * which we could use. | |
242 | */ | |
243 | if (flg_tc) goto x_truncated; | |
244 | ||
54ed1d64 | 245 | nsstart= cbyte; |
246 | ||
247 | if (!wantedrrs) { | |
9c344a42 | 248 | /* Oops, NODATA or NXDOMAIN or perhaps a referral |
249 | * (which would be a problem) */ | |
54ed1d64 | 250 | |
9c344a42 | 251 | /* RFC2308: NODATA has _either_ a SOA _or_ _no_ NS records |
252 | * in authority section */ | |
2c7b101b | 253 | foundsoa= 0; soattl= 0; foundns= 0; |
54ed1d64 | 254 | for (rri= 0; rri<nscount; rri++) { |
8312a1c2 | 255 | rrstart= cbyte; |
11c8bf9b | 256 | st= adns__findrr(qu,serv, dgram,dglen,&cbyte, |
2c7b101b | 257 | &rrtype,&rrclass,&ttl, &rdlength,&rdstart, 0); |
11c8bf9b | 258 | if (st) { adns__query_fail(qu,st); return; } |
8312a1c2 | 259 | if (rrtype==-1) goto x_truncated; |
260 | if (rrclass != DNS_CLASS_IN) { | |
7f702335 | 261 | adns__diag(ads,serv,qu, |
9c344a42 | 262 | "ignoring authority RR with wrong class %d" |
263 | " (expected IN=%d)", rrclass,DNS_CLASS_IN); | |
8312a1c2 | 264 | continue; |
265 | } | |
2c7b101b | 266 | if (rrtype == adns_r_soa_raw) { foundsoa= 1; soattl= ttl; break; } |
8312a1c2 | 267 | else if (rrtype == adns_r_ns_raw) { foundns= 1; } |
54ed1d64 | 268 | } |
2c7b101b | 269 | |
270 | if (rcode == rcode_nxdomain) { | |
271 | /* We still wanted to look for the SOA so we could find the TTL. */ | |
272 | adns__update_expires(qu,soattl,now); | |
7e6a84a1 | 273 | |
85021e18 | 274 | if (qu->flags & adns_qf_search && !qu->cname_dgram) { |
7e6a84a1 | 275 | adns__search_next(ads,qu,now); |
276 | } else { | |
277 | adns__query_fail(qu,adns_s_nxdomain); | |
278 | } | |
2c7b101b | 279 | return; |
280 | } | |
8312a1c2 | 281 | |
282 | if (foundsoa || !foundns) { | |
283 | /* Aha ! A NODATA response, good. */ | |
2c7b101b | 284 | adns__update_expires(qu,soattl,now); |
11c8bf9b | 285 | adns__query_fail(qu,adns_s_nodata); |
8312a1c2 | 286 | return; |
287 | } | |
288 | ||
289 | /* Now what ? No relevant answers, no SOA, and at least some NS's. | |
290 | * Looks like a referral. Just one last chance ... if we came across | |
7f702335 | 291 | * a CNAME in this datagram then we should probably do our own CNAME |
292 | * lookup now in the hope that we won't get a referral again. | |
8312a1c2 | 293 | */ |
f2ad23ee | 294 | if (cname_here) goto x_restartquery; |
8312a1c2 | 295 | |
296 | /* Bloody hell, I thought we asked for recursion ? */ | |
297 | if (!flg_ra) { | |
9c344a42 | 298 | adns__diag(ads,serv,qu,"server is not willing" |
299 | " to do recursive lookups for us"); | |
11c8bf9b | 300 | adns__query_fail(qu,adns_s_norecurse); |
7f702335 | 301 | } else { |
49ebbd58 | 302 | if (!flg_rd) |
9c344a42 | 303 | adns__diag(ads,serv,qu,"server thinks" |
304 | " we didn't ask for recursive lookup"); | |
49ebbd58 | 305 | else |
9c344a42 | 306 | adns__debug(ads,serv,qu,"server claims to do recursion," |
307 | " but gave us a referral"); | |
9b86645c | 308 | adns__query_fail(qu,adns_s_invalidresponse); |
8312a1c2 | 309 | } |
54ed1d64 | 310 | return; |
311 | } | |
312 | ||
8312a1c2 | 313 | /* Now, we have some RRs which we wanted. */ |
54ed1d64 | 314 | |
5f8085b7 | 315 | qu->answer->rrs.untyped= adns__alloc_interim(qu,qu->answer->rrsz*wantedrrs); |
9c344a42 | 316 | if (!qu->answer->rrs.untyped) { |
317 | adns__query_fail(qu,adns_s_nomemory); | |
318 | return; | |
319 | } | |
5c596e4d | 320 | |
f2ad23ee | 321 | typei= qu->typei; |
5c596e4d | 322 | cbyte= anstart; |
f2ad23ee | 323 | rrsdata= qu->answer->rrs.bytes; |
26eb6bdc | 324 | |
325 | pai.ads= qu->ads; | |
326 | pai.qu= qu; | |
327 | pai.serv= serv; | |
328 | pai.dgram= dgram; | |
329 | pai.dglen= dglen; | |
330 | pai.nsstart= nsstart; | |
331 | pai.nscount= nscount; | |
332 | pai.arcount= arcount; | |
ba1ddf08 | 333 | pai.now= now; |
26eb6bdc | 334 | |
335 | for (rri=0, nrrs=0; rri<ancount; rri++) { | |
11c8bf9b | 336 | st= adns__findrr(qu,serv, dgram,dglen,&cbyte, |
2c7b101b | 337 | &rrtype,&rrclass,&ttl, &rdlength,&rdstart, |
11c8bf9b | 338 | &ownermatched); |
5c596e4d | 339 | assert(!st); assert(rrtype != -1); |
340 | if (rrclass != DNS_CLASS_IN || | |
7d0aaee4 | 341 | rrtype != (qu->answer->type & adns_rrt_typemask) || |
7f702335 | 342 | !ownermatched) |
5c596e4d | 343 | continue; |
2c7b101b | 344 | adns__update_expires(qu,ttl,now); |
5f8085b7 MW |
345 | st= typei->parse(&pai, rdstart,rdstart+rdlength, |
346 | rrsdata+nrrs*qu->answer->rrsz); | |
11c8bf9b | 347 | if (st) { adns__query_fail(qu,st); return; } |
7f702335 | 348 | if (rdstart==-1) goto x_truncated; |
f2ad23ee | 349 | nrrs++; |
5c596e4d | 350 | } |
f2ad23ee | 351 | assert(nrrs==wantedrrs); |
352 | qu->answer->nrrs= nrrs; | |
54ed1d64 | 353 | |
5c596e4d | 354 | /* This may have generated some child queries ... */ |
355 | if (qu->children.head) { | |
d0a057ac | 356 | qu->state= query_childw; |
5c596e4d | 357 | LIST_LINK_TAIL(ads->childw,qu); |
358 | return; | |
54ed1d64 | 359 | } |
11c8bf9b | 360 | adns__query_done(qu); |
5c596e4d | 361 | return; |
8312a1c2 | 362 | |
98db6da3 | 363 | x_truncated: |
f2ad23ee | 364 | |
5c596e4d | 365 | if (!flg_tc) { |
7f702335 | 366 | adns__diag(ads,serv,qu,"server sent datagram which points outside itself"); |
9b86645c | 367 | adns__query_fail(qu,adns_s_invalidresponse); |
5c596e4d | 368 | return; |
369 | } | |
5c596e4d | 370 | qu->flags |= adns_qf_usevc; |
f2ad23ee | 371 | |
372 | x_restartquery: | |
f2ad23ee | 373 | if (qu->cname_dgram) { |
374 | st= adns__mkquery_frdgram(qu->ads,&qu->vb,&qu->id, | |
9c344a42 | 375 | qu->cname_dgram,qu->cname_dglen,qu->cname_begin, |
7d0aaee4 | 376 | qu->answer->type, qu->flags); |
f2ad23ee | 377 | if (st) { adns__query_fail(qu,st); return; } |
378 | ||
379 | newquery= realloc(qu->query_dgram,qu->vb.used); | |
9b86645c | 380 | if (!newquery) { adns__query_fail(qu,adns_s_nomemory); return; } |
f2ad23ee | 381 | |
382 | qu->query_dgram= newquery; | |
383 | qu->query_dglen= qu->vb.used; | |
384 | memcpy(newquery,qu->vb.buf,qu->vb.used); | |
385 | } | |
386 | ||
d0a057ac | 387 | if (qu->state == query_tcpw) qu->state= query_tosend; |
388 | qu->retries= 0; | |
1be24aef | 389 | adns__reset_preserved(qu); |
24d52b13 | 390 | adns__query_send(qu,now); |
5c596e4d | 391 | } |