5 static void cname_recurse(adns_state ads, adns_query qu, adns_queryflags xflags) {
9 void adns__procdgram(adns_state ads, const byte *dgram, int dglen,
10 int serv, struct timeval now) {
11 int cbyte, rrstart, wantedrrs, rri, foundsoa, foundns;
12 int id, f1, f2, qdcount, ancount, nscount, arcount, flg_ra, flg_rd, flg_tc, opcode;
13 int rrtype, rrclass, rdlength, rdstart, ownermatched, ownerstart;
14 int anstart, nsstart, arstart;
20 #error init and free vb properly
22 if (dglen<DNS_HDRSIZE) {
23 adns__diag(ads,serv,"received datagram too short for message header (%d)",dglen);
33 assert(cbyte == DNS_HDRSIZE);
43 adns__diag(ads,serv,"server sent us a query, not a response");
47 adns__diag(ads,serv,"server sent us unknown opcode %d (wanted 0=QUERY)",opcode);
51 adns__diag(ads,serv,"server sent reply without quoting our question");
53 } else if (qdcount>1) {
54 adns__diag(ads,serv,"server claimed to answer %d questions with one message",
58 for (qu= ads->timew.head; qu; qu= nqu) {
60 if (qu->id != id) continue;
61 if (dglen < qu->querylen) continue;
62 if (memcmp(qu->querymsg+DNS_HDRSIZE,dgram+DNS_HDRSIZE,qu->querylen-DNS_HDRSIZE))
66 assert(qu->cnameoff == -1);
67 anstart= qu->querylen;
69 adns__debug(ads,serv,"reply not found (id=%02x)",id);
73 LIST_UNLINK(ads->timew,qu);
74 /* We're definitely going to do something with this query now */
80 case rcode_formaterror:
81 adns__warn(ads,serv,qu,"server cannot understand our query (Format Error)");
82 adns__query_fail(ads,qu,adns_s_serverfaulty);
85 adns__query_fail(ads,qu,adns_s_servfail);
88 adns__warn(ads,serv,qu,"server claims not to implement our query");
89 adns__query_fail(ads,qu,adns_s_notimplemented);
92 adns__warn(ads,serv,qu,"server refused our query");
93 adns__query_fail(ads,qu,adns_s_refused);
96 adns__warn(ads,serv,qu,"server gave unknown response code %d",rcode);
97 adns__query_fail(ads,qu,adns_s_reasonunknown);
101 /* Now, take a look at the answer section, and see if it is complete.
102 * If it has any CNAMEs we stuff them in the answer.
105 for (rri= 0; rri<ancount; rri++) {
107 if (qu->cname_dgram >= 0) {
108 st= adns__findrr(ads,serv, dgram,dglen,&cbyte,
109 &rrtype,&rrclass,&rdlength,&rdstart,
110 qu->cname_dgram,qu->cname_dglen,qu->cname_begin, &ownermatched);
112 st= adns__findrr(ads,serv, dgram,dglen,&cbyte,
113 &rrtype,&rrclass,&rdlength,&rdstart,
114 qu->querymsg,qu->querylen,DNS_HDRSIZE, &ownermatched);
116 if (st) adns__query_fail(ads,qu,st);
117 if (rrtype == -1) goto x_truncated;
119 if (rrclass != DNS_CLASS_IN) {
120 adns__diag(ads,serv,qu,"ignoring answer RR with wrong class %d (expected IN=%d)",
121 rrclass,DNS_CLASS_IN);
125 if (ads->iflags & adns_if_debug) {
126 adns__debug(ads,serv,qu,"ignoring RR with an unexpected owner %s",
127 adns__diag_domain(ads,serv,&vb,qu->flags,
128 dgram,dglen,rrstart,dglen));
132 if (rrtype == adns_r_cname &&
133 (qu->typei->type & adns__rrt_typemask) != adns_r_cname) {
134 if (!qu->cname_str) { /* Ignore second and subsequent CNAMEs */
135 qu->cname_begin= rdstart;
136 qu->cname_dgram= dgram;
137 qu->cname_dglen= dglen;
138 st= adns__parse_domain(ads,serv,&vb,qu->flags,
139 dgram,dglen, &rdstart,rdstart+rdlength);
140 if (!vb.used) goto x_truncated;
141 if (st) { adns__query_fail(ads,qu,st); return; }
142 qu->cname_str= adns__vbuf_extractstring(&vb);
143 /* If we find the answer section truncated after this point we restart
144 * the query at the CNAME; if beforehand then we obviously have to use
145 * TCP. If there is no truncation we can use the whole answer if
146 * it contains the relevant info.
149 adns__debug(ads,serv,qu,"ignoring duplicate CNAME (%s, as well as %s)",
150 adns__diag_domain(ads,serv,&vb,qu->flags,
151 dgram,dglen, rdstart,rdstart+rdlength),
154 } else if (rrtype == (qu->typei->type & adns__rrt_typemask)) {
157 adns__debug(ads,serv,qu,"ignoring answer RR with irrelevant type %d",rrtype);
161 /* If we got here then the answer section is intact. */
165 /* Oops, NODATA or NXDOMAIN or perhaps a referral (which would be a problem) */
167 if (rcode == rcode_nxdomain) {
168 adns__query_finish(ads,qu,adns_s_nxdomain);
172 /* RFC2308: NODATA has _either_ a SOA _or_ _no_ NS records in authority section */
173 foundsoa= 0; foundns= 0;
174 for (rri= 0; rri<nscount; rri++) {
176 st= adns__findrr(ads,serv, dgram,dglen,&cbyte,
177 &rrtype,&rrclass,&rdlength,&rdstart,
179 if (st) { adns__query_fail(ads,qu,st); return; }
180 if (rrtype==-1) goto x_truncated;
181 if (rrclass != DNS_CLASS_IN) {
182 adns__diag(ads,serv,qu,
183 "ignoring authority RR with wrong class %d (expected IN=%d)",
184 rrclass,DNS_CLASS_IN);
187 if (rrtype == adns_r_soa_raw) { foundsoa= 1; break; }
188 else if (rrtype == adns_r_ns_raw) { foundns= 1; }
191 if (foundsoa || !foundns) {
192 /* Aha ! A NODATA response, good. */
193 adns__query_finish(ads,qu,adns_s_nodata);
197 /* Now what ? No relevant answers, no SOA, and at least some NS's.
198 * Looks like a referral. Just one last chance ... if we came across
199 * a CNAME in this datagram then we should probably do our own CNAME
200 * lookup now in the hope that we won't get a referral again.
202 if (qu->cname_dgram == dgram) { cname_recurse(ads,qu,0); return; }
204 /* Bloody hell, I thought we asked for recursion ? */
206 adns__diag(ads,serv,qu,"server thinks we didn't ask for recursive lookup");
209 adns__diag(ads,serv,qu,"server is not willing to do recursive lookups for us");
210 adns__query_fail(ads,qu,adns_s_norecurse);
212 adns__diag(ads,serv,qu,"server claims to do recursion, but gave us a referral");
213 adns__query_fail(ads,qu,adns_s_serverfaulty);
218 /* Now, we have some RRs which we wanted. */
220 if (!adns__vbuf_ensure(&qu->ansbuf,qu->typei->rrsz*wantedrrs)) {
221 adns__query_fail(ads,qu,adns_s_nolocalmem);
229 for (rri=0; rri<ancount; rri++) {
230 if (qu->cname_dgram >= 0) {
231 st= adns__findrr(ads,serv, dgram,dglen,&cbyte,
232 &rrtype,&rrclass,&rdlength,&rdstart,
233 qu->cname_dgram,qu->cname_dglen,qu->cname_begin, &ownermatched);
235 st= adns__findrr(ads,serv, dgram,dglen,&cbyte,
236 &rrtype,&rrclass,&rdlength,&rdstart,
237 qu->querymsg,qu->querylen,DNS_HDRSIZE, &ownermatched);
239 assert(!st); assert(rrtype != -1);
240 if (rrclass != DNS_CLASS_IN ||
241 rrtype != (qu->typei->type & adns__rrt_typemask) ||
244 assert(currentrrs<wantedrrs);
245 qu->ansbuf.used += quj->typei->rrsz;
246 st= qu->typei->parse(ads,qu,serv,&vb,
247 dgram,dglen, &rdstart,rdstart+rdlength,
248 (void*)(qu->ansbuf.buf+qu->ansbuf.used));
249 if (st) { adns__query_fail(ads,qu,st); return; }
250 if (rdstart==-1) goto x_truncated;
253 /* This may have generated some child queries ... */
254 if (qu->children.head) {
255 qu->state= query_child;
256 LIST_LINK_TAIL(ads->childw,qu);
260 adns__query_finish(ads,qu,adns_s_ok);
265 adns__diag(ads,serv,qu,"server sent datagram which points outside itself");
266 adns__query_fail(ads,qu,adns_s_serverfaulty);
269 if (qu->cname_dgram) { cname_recurse(ads,qu,adns_qf_usevc); return; }
270 ans= (adns_answer*)qu->ans.buf;
272 qu->ans.used= sizeof(adns_answer);
273 qu->flags |= adns_qf_usevc;
274 adns__query_udp(ads,qu,now);