Rearrangement more or less sorted, back to trying to get it to compile.
[adns] / src / reply.c
CommitLineData
e576be50 1/*
2 * reply.c
3 * - main handling and parsing routine for received datagrams
4 */
5/*
6 * This file is part of adns, which is Copyright (C) 1997, 1998 Ian Jackson
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2, or (at your option)
11 * any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software Foundation,
20 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
21 */
4353a5c4 22
23#include "internal.h"
24
98a3f706 25static void cname_recurse(adns_state ads, adns_query qu, adns_queryflags xflags) {
26 abort(); /* FIXME */
b9de380c 27}
28
98a3f706 29void adns__procdgram(adns_state ads, const byte *dgram, int dglen,
30 int serv, struct timeval now) {
31 int cbyte, rrstart, wantedrrs, rri, foundsoa, foundns;
31144a72 32 int id, f1, f2, qdcount, ancount, nscount, arcount, flg_ra, flg_rd, flg_tc, opcode;
98a3f706 33 int rrtype, rrclass, rdlength, rdstart, ownermatched, ownerstart;
34 int anstart, nsstart, arstart;
35 int currentrrs;
36 adns_query qu, nqu;
37 dns_rcode rcode;
b9de380c 38 adns_status st;
ec477b9e 39
98a3f706 40 if (dglen<DNS_HDRSIZE) {
41 adns__diag(ads,serv,"received datagram too short for message header (%d)",dglen);
ec477b9e 42 return;
43 }
b9de380c 44 GET_W(cbyte,id);
45 GET_B(cbyte,f1);
46 GET_B(cbyte,f2);
47 GET_W(cbyte,qdcount);
48 GET_W(cbyte,ancount);
49 GET_W(cbyte,nscount);
50 GET_W(cbyte,arcount);
98a3f706 51 assert(cbyte == DNS_HDRSIZE);
ec477b9e 52
31144a72 53 flg_qr= f1&0x80;
54 opcode= (f1&0x78)>>3;
98a3f706 55 flg_tc= f1&0x20;
31144a72 56 flg_rd= f1&0x01;
0ba0614a 57 flg_ra= f2&0x80;
31144a72 58 rcode= (f1&0x0f);
0ba0614a 59
31144a72 60 if (flg_qr) {
ec477b9e 61 adns__diag(ads,serv,"server sent us a query, not a response");
62 return;
63 }
31144a72 64 if (opcode) {
65 adns__diag(ads,serv,"server sent us unknown opcode %d (wanted 0=QUERY)",opcode);
ec477b9e 66 return;
67 }
68 if (!qdcount) {
69 adns__diag(ads,serv,"server sent reply without quoting our question");
70 return;
71 } else if (qdcount>1) {
72 adns__diag(ads,serv,"server claimed to answer %d questions with one message",
73 qdcount);
74 return;
75 }
98a3f706 76 for (qu= ads->timew.head; qu; qu= nqu) {
ec477b9e 77 nqu= qu->next;
78 if (qu->id != id) continue;
98a3f706 79 if (dglen < qu->querylen) continue;
80 if (memcmp(qu->querymsg+DNS_HDRSIZE,dgram+DNS_HDRSIZE,qu->querylen-DNS_HDRSIZE))
b9de380c 81 continue;
ec477b9e 82 break;
83 }
98a3f706 84 assert(qu->cnameoff == -1);
b9de380c 85 anstart= qu->querylen;
ec477b9e 86 if (!qu) {
87 adns__debug(ads,serv,"reply not found (id=%02x)",id);
88 return;
89 }
98a3f706 90
91 LIST_UNLINK(ads->timew,qu);
92 /* We're definitely going to do something with this query now */
93
b9de380c 94 switch (rcode) {
95 case rcode_noerror:
96 case rcode_nxdomain:
ec477b9e 97 break;
b9de380c 98 case rcode_formaterror:
31144a72 99 adns__warn(ads,serv,qu,"server cannot understand our query (Format Error)");
ec477b9e 100 adns__query_fail(ads,qu,adns_s_serverfaulty);
101 return;
98a3f706 102 case rcode_servfail:
103 adns__query_fail(ads,qu,adns_s_servfail);
ec477b9e 104 return;
b9de380c 105 case rcode_notimp:
31144a72 106 adns__warn(ads,serv,qu,"server claims not to implement our query");
b9de380c 107 adns__query_fail(ads,qu,adns_s_notimplemented);
108 return;
109 case rcode_refused:
31144a72 110 adns__warn(ads,serv,qu,"server refused our query");
b9de380c 111 adns__query_fail(ads,qu,adns_s_refused);
112 return;
113 default:
31144a72 114 adns__warn(ads,serv,qu,"server gave unknown response code %d",rcode);
b9de380c 115 adns__query_fail(ads,qu,adns_s_reasonunknown);
116 return;
117 }
118
119 /* Now, take a look at the answer section, and see if it is complete.
120 * If it has any CNAMEs we stuff them in the answer.
121 */
122 wantedrrs= 0;
123 for (rri= 0; rri<ancount; rri++) {
124 rrstart= cbyte;
31144a72 125 if (qu->cname_dgram >= 0) {
f1e474dd 126 st= adns__findrr(ads,serv, dgram,dglen,&cbyte,
127 &rrtype,&rrclass,&rdlength,&rdstart,
31144a72 128 qu->cname_dgram,qu->cname_dglen,qu->cname_begin, &ownermatched);
0ba0614a 129 } else {
31144a72 130 st= adns__findrr(ads,serv, dgram,dglen,&cbyte,
131 &rrtype,&rrclass,&rdlength,&rdstart,
132 qu->querymsg,qu->querylen,DNS_HDRSIZE, &ownermatched);
0ba0614a 133 }
b9de380c 134 if (st) adns__query_fail(ads,qu,st);
0ba0614a 135 if (rrtype == -1) goto x_truncated;
136
b9de380c 137 if (rrclass != DNS_CLASS_IN) {
31144a72 138 adns__diag(ads,serv,qu,"ignoring answer RR with wrong class %d (expected IN=%d)",
b9de380c 139 rrclass,DNS_CLASS_IN);
140 continue;
141 }
0ba0614a 142 if (!ownermatched) {
98a3f706 143 if (ads->iflags & adns_if_debug) {
31144a72 144 adns__debug(ads,serv,qu,"ignoring RR with an unexpected owner %s",
8e5b0abb 145 adns__diag_domain(ads,serv,&qu->vb,qu->flags,
31144a72 146 dgram,dglen,rrstart,dglen));
0ba0614a 147 }
b9de380c 148 continue;
149 }
31144a72 150 if (rrtype == adns_r_cname &&
151 (qu->typei->type & adns__rrt_typemask) != adns_r_cname) {
152 if (!qu->cname_str) { /* Ignore second and subsequent CNAMEs */
153 qu->cname_begin= rdstart;
154 qu->cname_dgram= dgram;
155 qu->cname_dglen= dglen;
8e5b0abb 156 st= adns__parse_domain(ads,serv,&qu->vb,qu->flags,
31144a72 157 dgram,dglen, &rdstart,rdstart+rdlength);
158 if (!vb.used) goto x_truncated;
159 if (st) { adns__query_fail(ads,qu,st); return; }
8e5b0abb 160 qu->answer->cname= adns__savestring(qu);
161 if (!qu->answer->cname) return;
31144a72 162 /* If we find the answer section truncated after this point we restart
163 * the query at the CNAME; if beforehand then we obviously have to use
164 * TCP. If there is no truncation we can use the whole answer if
165 * it contains the relevant info.
166 */
167 } else {
168 adns__debug(ads,serv,qu,"ignoring duplicate CNAME (%s, as well as %s)",
8e5b0abb 169 adns__diag_domain(ads,serv,&qu->vb,qu->flags,
31144a72 170 dgram,dglen, rdstart,rdstart+rdlength),
171 qu->cname_str);
172 }
98a3f706 173 } else if (rrtype == (qu->typei->type & adns__rrt_typemask)) {
b9de380c 174 wantedrrs++;
175 } else {
31144a72 176 adns__debug(ads,serv,qu,"ignoring answer RR with irrelevant type %d",rrtype);
b9de380c 177 }
178 }
179
180 /* If we got here then the answer section is intact. */
181 nsstart= cbyte;
182
183 if (!wantedrrs) {
184 /* Oops, NODATA or NXDOMAIN or perhaps a referral (which would be a problem) */
185
186 if (rcode == rcode_nxdomain) {
0ba0614a 187 adns__query_finish(ads,qu,adns_s_nxdomain);
b9de380c 188 return;
189 }
190
191 /* RFC2308: NODATA has _either_ a SOA _or_ _no_ NS records in authority section */
0ba0614a 192 foundsoa= 0; foundns= 0;
b9de380c 193 for (rri= 0; rri<nscount; rri++) {
0ba0614a 194 rrstart= cbyte;
31144a72 195 st= adns__findrr(ads,serv, dgram,dglen,&cbyte,
196 &rrtype,&rrclass,&rdlength,&rdstart,
197 0,0,0,0);
98a3f706 198 if (st) { adns__query_fail(ads,qu,st); return; }
0ba0614a 199 if (rrtype==-1) goto x_truncated;
200 if (rrclass != DNS_CLASS_IN) {
31144a72 201 adns__diag(ads,serv,qu,
202 "ignoring authority RR with wrong class %d (expected IN=%d)",
0ba0614a 203 rrclass,DNS_CLASS_IN);
204 continue;
205 }
206 if (rrtype == adns_r_soa_raw) { foundsoa= 1; break; }
207 else if (rrtype == adns_r_ns_raw) { foundns= 1; }
b9de380c 208 }
0ba0614a 209
210 if (foundsoa || !foundns) {
211 /* Aha ! A NODATA response, good. */
212 adns__query_finish(ads,qu,adns_s_nodata);
213 return;
214 }
215
216 /* Now what ? No relevant answers, no SOA, and at least some NS's.
217 * Looks like a referral. Just one last chance ... if we came across
31144a72 218 * a CNAME in this datagram then we should probably do our own CNAME
219 * lookup now in the hope that we won't get a referral again.
0ba0614a 220 */
31144a72 221 if (qu->cname_dgram == dgram) { cname_recurse(ads,qu,0); return; }
0ba0614a 222
223 /* Bloody hell, I thought we asked for recursion ? */
31144a72 224 if (flg_rd) {
225 adns__diag(ads,serv,qu,"server thinks we didn't ask for recursive lookup");
226 }
0ba0614a 227 if (!flg_ra) {
31144a72 228 adns__diag(ads,serv,qu,"server is not willing to do recursive lookups for us");
0ba0614a 229 adns__query_fail(ads,qu,adns_s_norecurse);
31144a72 230 } else {
231 adns__diag(ads,serv,qu,"server claims to do recursion, but gave us a referral");
232 adns__query_fail(ads,qu,adns_s_serverfaulty);
0ba0614a 233 }
b9de380c 234 return;
235 }
236
0ba0614a 237 /* Now, we have some RRs which we wanted. */
b9de380c 238
8e5b0abb 239 qu->ans->rrs= adns__alloc_interim(qu,qu->typei->rrsz*wantedrrs);
240 if (!qu->ans->rrs) return;
98a3f706 241
242 cbyte= anstart;
98a3f706 243 arstart= -1;
244 for (rri=0; rri<ancount; rri++) {
31144a72 245 if (qu->cname_dgram >= 0) {
246 st= adns__findrr(ads,serv, dgram,dglen,&cbyte,
247 &rrtype,&rrclass,&rdlength,&rdstart,
248 qu->cname_dgram,qu->cname_dglen,qu->cname_begin, &ownermatched);
249 } else {
250 st= adns__findrr(ads,serv, dgram,dglen,&cbyte,
251 &rrtype,&rrclass,&rdlength,&rdstart,
252 qu->querymsg,qu->querylen,DNS_HDRSIZE, &ownermatched);
253 }
98a3f706 254 assert(!st); assert(rrtype != -1);
255 if (rrclass != DNS_CLASS_IN ||
31144a72 256 rrtype != (qu->typei->type & adns__rrt_typemask) ||
257 !ownermatched)
98a3f706 258 continue;
8e5b0abb 259 assert(qu->ans->nrrs<wantedrrs);
260 st= qu->typei->parse(ads,qu,serv,
31144a72 261 dgram,dglen, &rdstart,rdstart+rdlength,
8e5b0abb 262 qu->ans->rrs.bytes+qu->ans->nrrs*quj->typei->rrsz);
98a3f706 263 if (st) { adns__query_fail(ads,qu,st); return; }
31144a72 264 if (rdstart==-1) goto x_truncated;
98a3f706 265 }
b9de380c 266
98a3f706 267 /* This may have generated some child queries ... */
268 if (qu->children.head) {
269 qu->state= query_child;
270 LIST_LINK_TAIL(ads->childw,qu);
271 return;
b9de380c 272 }
ec477b9e 273
98a3f706 274 adns__query_finish(ads,qu,adns_s_ok);
275 return;
0ba0614a 276
e576be50 277 x_truncated:
98a3f706 278 if (!flg_tc) {
31144a72 279 adns__diag(ads,serv,qu,"server sent datagram which points outside itself");
98a3f706 280 adns__query_fail(ads,qu,adns_s_serverfaulty);
281 return;
282 }
31144a72 283 if (qu->cname_dgram) { cname_recurse(ads,qu,adns_qf_usevc); return; }
8e5b0abb 284 adns__reset_cnameonly(ads,qu);
98a3f706 285 qu->flags |= adns_qf_usevc;
286 adns__query_udp(ads,qu,now);
287}