Add fixme.
[adns] / src / reply.c
CommitLineData
98db6da3 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 */
d05cc330 22
23#include "internal.h"
24
11c8bf9b 25static void cname_recurse(adns_query qu, adns_queryflags xflags) {
5c596e4d 26 abort(); /* FIXME */
54ed1d64 27}
28
5c596e4d 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;
11c8bf9b 32 int id, f1, f2, qdcount, ancount, nscount, arcount;
33 int flg_ra, flg_rd, flg_tc, flg_qr, opcode;
34 int rrtype, rrclass, rdlength, rdstart, ownermatched, l;
5c596e4d 35 int anstart, nsstart, arstart;
5c596e4d 36 adns_query qu, nqu;
37 dns_rcode rcode;
54ed1d64 38 adns_status st;
168e26fe 39
5c596e4d 40 if (dglen<DNS_HDRSIZE) {
11c8bf9b 41 adns__diag(ads,serv,0,"received datagram too short for message header (%d)",dglen);
168e26fe 42 return;
43 }
9a2b67d4 44 cbyte= 0;
54ed1d64 45 GET_W(cbyte,id);
46 GET_B(cbyte,f1);
47 GET_B(cbyte,f2);
48 GET_W(cbyte,qdcount);
49 GET_W(cbyte,ancount);
50 GET_W(cbyte,nscount);
51 GET_W(cbyte,arcount);
5c596e4d 52 assert(cbyte == DNS_HDRSIZE);
168e26fe 53
7f702335 54 flg_qr= f1&0x80;
55 opcode= (f1&0x78)>>3;
5c596e4d 56 flg_tc= f1&0x20;
7f702335 57 flg_rd= f1&0x01;
8312a1c2 58 flg_ra= f2&0x80;
7f702335 59 rcode= (f1&0x0f);
680d2a65 60 /* fixme: change this to f2 (which is where rcode really is), BUT
61 * not until we've figured out why the error code is wrong (bad format code 203)
62 */
8312a1c2 63
9a2b67d4 64 if (!flg_qr) {
11c8bf9b 65 adns__diag(ads,serv,0,"server sent us a query, not a response");
168e26fe 66 return;
67 }
7f702335 68 if (opcode) {
11c8bf9b 69 adns__diag(ads,serv,0,"server sent us unknown opcode %d (wanted 0=QUERY)",opcode);
168e26fe 70 return;
71 }
72 if (!qdcount) {
11c8bf9b 73 adns__diag(ads,serv,0,"server sent reply without quoting our question");
168e26fe 74 return;
75 } else if (qdcount>1) {
11c8bf9b 76 adns__diag(ads,serv,0,"server claimed to answer %d questions with one message",
168e26fe 77 qdcount);
78 return;
79 }
5c596e4d 80 for (qu= ads->timew.head; qu; qu= nqu) {
168e26fe 81 nqu= qu->next;
82 if (qu->id != id) continue;
11c8bf9b 83 if (dglen < qu->query_dglen) continue;
84 if (memcmp(qu->query_dgram+DNS_HDRSIZE,
85 dgram+DNS_HDRSIZE,
86 qu->query_dglen-DNS_HDRSIZE))
54ed1d64 87 continue;
168e26fe 88 break;
89 }
11c8bf9b 90 anstart= qu->query_dglen;
168e26fe 91 if (!qu) {
11c8bf9b 92 adns__debug(ads,serv,0,"reply not found (id=%02x)",id);
168e26fe 93 return;
94 }
5c596e4d 95
96 LIST_UNLINK(ads->timew,qu);
97 /* We're definitely going to do something with this query now */
98
54ed1d64 99 switch (rcode) {
100 case rcode_noerror:
101 case rcode_nxdomain:
168e26fe 102 break;
54ed1d64 103 case rcode_formaterror:
7f702335 104 adns__warn(ads,serv,qu,"server cannot understand our query (Format Error)");
11c8bf9b 105 adns__query_fail(qu,adns_s_serverfaulty);
168e26fe 106 return;
5c596e4d 107 case rcode_servfail:
11c8bf9b 108 adns__query_fail(qu,adns_s_servfail);
168e26fe 109 return;
54ed1d64 110 case rcode_notimp:
7f702335 111 adns__warn(ads,serv,qu,"server claims not to implement our query");
11c8bf9b 112 adns__query_fail(qu,adns_s_notimplemented);
54ed1d64 113 return;
114 case rcode_refused:
7f702335 115 adns__warn(ads,serv,qu,"server refused our query");
11c8bf9b 116 adns__query_fail(qu,adns_s_refused);
54ed1d64 117 return;
118 default:
7f702335 119 adns__warn(ads,serv,qu,"server gave unknown response code %d",rcode);
11c8bf9b 120 adns__query_fail(qu,adns_s_reasonunknown);
54ed1d64 121 return;
122 }
123
124 /* Now, take a look at the answer section, and see if it is complete.
125 * If it has any CNAMEs we stuff them in the answer.
126 */
127 wantedrrs= 0;
128 for (rri= 0; rri<ancount; rri++) {
129 rrstart= cbyte;
11c8bf9b 130 st= adns__findrr(qu,serv, dgram,dglen,&cbyte,
131 &rrtype,&rrclass,&rdlength,&rdstart,
132 &ownermatched);
133 if (st) adns__query_fail(qu,st);
8312a1c2 134 if (rrtype == -1) goto x_truncated;
135
54ed1d64 136 if (rrclass != DNS_CLASS_IN) {
7f702335 137 adns__diag(ads,serv,qu,"ignoring answer RR with wrong class %d (expected IN=%d)",
54ed1d64 138 rrclass,DNS_CLASS_IN);
139 continue;
140 }
8312a1c2 141 if (!ownermatched) {
5c596e4d 142 if (ads->iflags & adns_if_debug) {
7f702335 143 adns__debug(ads,serv,qu,"ignoring RR with an unexpected owner %s",
11c8bf9b 144 adns__diag_domain(ads,serv,qu, &qu->vb,qu->flags,
145 dgram,dglen,rrstart));
8312a1c2 146 }
54ed1d64 147 continue;
148 }
7f702335 149 if (rrtype == adns_r_cname &&
150 (qu->typei->type & adns__rrt_typemask) != adns_r_cname) {
11c8bf9b 151 if (!qu->cname_dgram) { /* Ignore second and subsequent CNAMEs */
152 qu->cname_dgram= adns__alloc_mine(qu,dglen);
153 if (!qu->cname_dgram) return;
7f702335 154 qu->cname_begin= rdstart;
7f702335 155 qu->cname_dglen= dglen;
11c8bf9b 156 st= adns__parse_domain(ads,serv,qu, &qu->vb,qu->flags,
7f702335 157 dgram,dglen, &rdstart,rdstart+rdlength);
11c8bf9b 158 if (!qu->vb.used) goto x_truncated;
159 if (st) { adns__query_fail(qu,st); return; }
160 l= strlen(qu->vb.buf)+1;
161 qu->answer->cname= adns__alloc_interim(qu,l);
965c9782 162 if (!qu->answer->cname) return;
11c8bf9b 163 memcpy(qu->answer->cname,qu->vb.buf,l);
7f702335 164 /* If we find the answer section truncated after this point we restart
165 * the query at the CNAME; if beforehand then we obviously have to use
166 * TCP. If there is no truncation we can use the whole answer if
167 * it contains the relevant info.
168 */
169 } else {
170 adns__debug(ads,serv,qu,"ignoring duplicate CNAME (%s, as well as %s)",
11c8bf9b 171 adns__diag_domain(ads,serv,qu, &qu->vb,qu->flags,
172 dgram,dglen,rdstart),
173 qu->answer->cname);
7f702335 174 }
5c596e4d 175 } else if (rrtype == (qu->typei->type & adns__rrt_typemask)) {
54ed1d64 176 wantedrrs++;
177 } else {
7f702335 178 adns__debug(ads,serv,qu,"ignoring answer RR with irrelevant type %d",rrtype);
54ed1d64 179 }
180 }
181
182 /* If we got here then the answer section is intact. */
183 nsstart= cbyte;
184
185 if (!wantedrrs) {
186 /* Oops, NODATA or NXDOMAIN or perhaps a referral (which would be a problem) */
187
188 if (rcode == rcode_nxdomain) {
11c8bf9b 189 adns__query_fail(qu,adns_s_nxdomain);
54ed1d64 190 return;
191 }
192
193 /* RFC2308: NODATA has _either_ a SOA _or_ _no_ NS records in authority section */
8312a1c2 194 foundsoa= 0; foundns= 0;
54ed1d64 195 for (rri= 0; rri<nscount; rri++) {
8312a1c2 196 rrstart= cbyte;
11c8bf9b 197 st= adns__findrr(qu,serv, dgram,dglen,&cbyte,
198 &rrtype,&rrclass,&rdlength,&rdstart, 0);
199 if (st) { adns__query_fail(qu,st); return; }
8312a1c2 200 if (rrtype==-1) goto x_truncated;
201 if (rrclass != DNS_CLASS_IN) {
7f702335 202 adns__diag(ads,serv,qu,
203 "ignoring authority RR with wrong class %d (expected IN=%d)",
8312a1c2 204 rrclass,DNS_CLASS_IN);
205 continue;
206 }
207 if (rrtype == adns_r_soa_raw) { foundsoa= 1; break; }
208 else if (rrtype == adns_r_ns_raw) { foundns= 1; }
54ed1d64 209 }
8312a1c2 210
211 if (foundsoa || !foundns) {
212 /* Aha ! A NODATA response, good. */
11c8bf9b 213 adns__query_fail(qu,adns_s_nodata);
8312a1c2 214 return;
215 }
216
217 /* Now what ? No relevant answers, no SOA, and at least some NS's.
218 * Looks like a referral. Just one last chance ... if we came across
7f702335 219 * a CNAME in this datagram then we should probably do our own CNAME
220 * lookup now in the hope that we won't get a referral again.
8312a1c2 221 */
11c8bf9b 222 if (qu->cname_dgram == dgram) { cname_recurse(qu,0); return; }
8312a1c2 223
224 /* Bloody hell, I thought we asked for recursion ? */
7f702335 225 if (flg_rd) {
226 adns__diag(ads,serv,qu,"server thinks we didn't ask for recursive lookup");
227 }
8312a1c2 228 if (!flg_ra) {
7f702335 229 adns__diag(ads,serv,qu,"server is not willing to do recursive lookups for us");
11c8bf9b 230 adns__query_fail(qu,adns_s_norecurse);
7f702335 231 } else {
232 adns__diag(ads,serv,qu,"server claims to do recursion, but gave us a referral");
11c8bf9b 233 adns__query_fail(qu,adns_s_serverfaulty);
8312a1c2 234 }
54ed1d64 235 return;
236 }
237
8312a1c2 238 /* Now, we have some RRs which we wanted. */
54ed1d64 239
11c8bf9b 240 qu->answer->rrs.untyped= adns__alloc_interim(qu,qu->typei->rrsz*wantedrrs);
241 if (!qu->answer->rrs.untyped) return;
5c596e4d 242
243 cbyte= anstart;
5c596e4d 244 arstart= -1;
245 for (rri=0; rri<ancount; rri++) {
11c8bf9b 246 st= adns__findrr(qu,serv, dgram,dglen,&cbyte,
247 &rrtype,&rrclass,&rdlength,&rdstart,
248 &ownermatched);
5c596e4d 249 assert(!st); assert(rrtype != -1);
250 if (rrclass != DNS_CLASS_IN ||
7f702335 251 rrtype != (qu->typei->type & adns__rrt_typemask) ||
252 !ownermatched)
5c596e4d 253 continue;
11c8bf9b 254 assert(qu->answer->nrrs<wantedrrs);
255 st= qu->typei->parse(qu,serv,
256 dgram,dglen, rdstart,rdstart+rdlength,
257 qu->answer->rrs.bytes+qu->answer->nrrs*qu->typei->rrsz);
258 if (st) { adns__query_fail(qu,st); return; }
7f702335 259 if (rdstart==-1) goto x_truncated;
5c596e4d 260 }
54ed1d64 261
5c596e4d 262 /* This may have generated some child queries ... */
263 if (qu->children.head) {
264 qu->state= query_child;
265 LIST_LINK_TAIL(ads->childw,qu);
266 return;
54ed1d64 267 }
168e26fe 268
11c8bf9b 269 adns__query_done(qu);
5c596e4d 270 return;
8312a1c2 271
98db6da3 272 x_truncated:
5c596e4d 273 if (!flg_tc) {
7f702335 274 adns__diag(ads,serv,qu,"server sent datagram which points outside itself");
11c8bf9b 275 adns__query_fail(qu,adns_s_serverfaulty);
5c596e4d 276 return;
277 }
11c8bf9b 278 if (qu->cname_dgram) { cname_recurse(qu,adns_qf_usevc); return; }
279 adns__reset_cnameonly(qu);
5c596e4d 280 qu->flags |= adns_qf_usevc;
11c8bf9b 281 adns__query_udp(qu,now);
5c596e4d 282}