3 * - main handling and parsing routine for received datagrams
6 * This file is part of adns, which is Copyright (C) 1997, 1998 Ian Jackson
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)
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.
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.
28 void adns__procdgram(adns_state ads
, const byte
*dgram
, int dglen
,
29 int serv
, struct timeval now
) {
30 int cbyte
, rrstart
, wantedrrs
, rri
, foundsoa
, foundns
, cname_here
;
31 int id
, f1
, f2
, qdcount
, ancount
, nscount
, arcount
;
32 int flg_ra
, flg_rd
, flg_tc
, flg_qr
, opcode
;
33 int rrtype
, rrclass
, rdlength
, rdstart
;
34 int anstart
, nsstart
, arstart
;
35 int ownermatched
, l
, nrrs
;
36 const typeinfo
*typei
;
41 byte
*newquery
, *rrsdata
;
44 if (dglen
<DNS_HDRSIZE
) {
45 adns__diag(ads
,serv
,0,"received datagram too short for message header (%d)",dglen
);
56 assert(cbyte
== DNS_HDRSIZE
);
68 adns__diag(ads
,serv
,0,"server sent us a query, not a response");
72 adns__diag(ads
,serv
,0,"server sent us unknown opcode %d (wanted 0=QUERY)",opcode
);
76 adns__diag(ads
,serv
,0,"server sent reply without quoting our question");
78 } else if (qdcount
>1) {
79 adns__diag(ads
,serv
,0,"server claimed to answer %d questions with one message",
83 for (qu
= ads
->timew
.head
; qu
; qu
= nqu
) {
85 if (qu
->id
!= id
) continue;
86 if (dglen
< qu
->query_dglen
) continue;
87 if (memcmp(qu
->query_dgram
+DNS_HDRSIZE
,
89 qu
->query_dglen
-DNS_HDRSIZE
))
94 if (ads
->iflags
& adns_if_debug
) {
95 adns__vbuf_init(&tempvb
);
96 adns__debug(ads
,serv
,0,"reply not found, id %02x, query owner %s",
97 id
, adns__diag_domain(ads
,serv
,0,&tempvb
,dgram
,dglen
,DNS_HDRSIZE
));
98 adns__vbuf_free(&tempvb
);
102 anstart
= qu
->query_dglen
;
105 LIST_UNLINK(ads
->timew
,qu
);
106 /* We're definitely going to do something with this query now */
112 case rcode_formaterror
:
113 adns__warn(ads
,serv
,qu
,"server cannot understand our query (Format Error)");
114 adns__query_fail(qu
,adns_s_rcodeformaterror
);
117 adns__query_fail(qu
,adns_s_rcodeservfail
);
120 adns__warn(ads
,serv
,qu
,"server claims not to implement our query");
121 adns__query_fail(qu
,adns_s_rcodenotimplemented
);
124 adns__warn(ads
,serv
,qu
,"server refused our query");
125 adns__query_fail(qu
,adns_s_rcoderefused
);
128 adns__warn(ads
,serv
,qu
,"server gave unknown response code %d",rcode
);
129 adns__query_fail(qu
,adns_s_rcodeunknown
);
133 /* Now, take a look at the answer section, and see if it is complete.
134 * If it has any CNAMEs we stuff them in the answer.
138 for (rri
= 0; rri
<ancount
; rri
++) {
140 st
= adns__findrr(qu
,serv
, dgram
,dglen
,&cbyte
,
141 &rrtype
,&rrclass
,&rdlength
,&rdstart
,
143 if (st
) { adns__query_fail(qu
,st
); return; }
144 if (rrtype
== -1) goto x_truncated
;
146 if (rrclass
!= DNS_CLASS_IN
) {
147 adns__diag(ads
,serv
,qu
,"ignoring answer RR with wrong class %d (expected IN=%d)",
148 rrclass
,DNS_CLASS_IN
);
152 if (ads
->iflags
& adns_if_debug
) {
153 adns__debug(ads
,serv
,qu
,"ignoring RR with an unexpected owner %s",
154 adns__diag_domain(ads
,serv
,qu
, &qu
->vb
, dgram
,dglen
,rrstart
));
158 if (rrtype
== adns_r_cname
&& /* fixme - implement adns_qf_nocname */
159 (qu
->typei
->type
& adns__rrt_typemask
) != adns_r_cname
) {
160 if (!qu
->cname_dgram
) { /* Ignore second and subsequent CNAMEs */
161 qu
->cname_begin
= rdstart
;
162 qu
->cname_dglen
= dglen
;
163 st
= adns__parse_domain(ads
,serv
,qu
, &qu
->vb
,
164 qu
->flags
& adns_qf_quoteok_cname ? pdf_quoteok
: 0,
165 dgram
,dglen
, &rdstart
,rdstart
+rdlength
);
166 if (!qu
->vb
.used
) goto x_truncated
;
167 if (st
) { adns__query_fail(qu
,st
); return; }
168 l
= strlen(qu
->vb
.buf
)+1;
169 qu
->answer
->cname
= adns__alloc_interim(qu
,l
);
170 if (!qu
->answer
->cname
) { adns__query_fail(qu
,adns_s_nomemory
); return; }
172 qu
->cname_dgram
= adns__alloc_mine(qu
,dglen
);
173 memcpy(qu
->cname_dgram
,dgram
,dglen
);
175 memcpy(qu
->answer
->cname
,qu
->vb
.buf
,l
);
177 /* If we find the answer section truncated after this point we restart
178 * the query at the CNAME; if beforehand then we obviously have to use
179 * TCP. If there is no truncation we can use the whole answer if
180 * it contains the relevant info.
183 adns__debug(ads
,serv
,qu
,"ignoring duplicate CNAME (%s, as well as %s)",
184 adns__diag_domain(ads
,serv
,qu
, &qu
->vb
, dgram
,dglen
,rdstart
),
187 } else if (rrtype
== (qu
->typei
->type
& adns__rrt_typemask
)) {
190 adns__debug(ads
,serv
,qu
,"ignoring answer RR with irrelevant type %d",rrtype
);
194 /* We defer handling truncated responses here, in case there was a CNAME
195 * which we could use.
197 if (flg_tc
) goto x_truncated
;
202 /* Oops, NODATA or NXDOMAIN or perhaps a referral (which would be a problem) */
204 if (rcode
== rcode_nxdomain
) {
205 adns__query_fail(qu
,adns_s_nxdomain
);
209 /* RFC2308: NODATA has _either_ a SOA _or_ _no_ NS records in authority section */
210 foundsoa
= 0; foundns
= 0;
211 for (rri
= 0; rri
<nscount
; rri
++) {
213 st
= adns__findrr(qu
,serv
, dgram
,dglen
,&cbyte
,
214 &rrtype
,&rrclass
,&rdlength
,&rdstart
, 0);
215 if (st
) { adns__query_fail(qu
,st
); return; }
216 if (rrtype
==-1) goto x_truncated
;
217 if (rrclass
!= DNS_CLASS_IN
) {
218 adns__diag(ads
,serv
,qu
,
219 "ignoring authority RR with wrong class %d (expected IN=%d)",
220 rrclass
,DNS_CLASS_IN
);
223 if (rrtype
== adns_r_soa_raw
) { foundsoa
= 1; break; }
224 else if (rrtype
== adns_r_ns_raw
) { foundns
= 1; }
227 if (foundsoa
|| !foundns
) {
228 /* Aha ! A NODATA response, good. */
229 adns__query_fail(qu
,adns_s_nodata
);
233 /* Now what ? No relevant answers, no SOA, and at least some NS's.
234 * Looks like a referral. Just one last chance ... if we came across
235 * a CNAME in this datagram then we should probably do our own CNAME
236 * lookup now in the hope that we won't get a referral again.
238 if (cname_here
) goto x_restartquery
;
240 /* Bloody hell, I thought we asked for recursion ? */
242 adns__diag(ads
,serv
,qu
,"server thinks we didn't ask for recursive lookup");
245 adns__diag(ads
,serv
,qu
,"server is not willing to do recursive lookups for us");
246 adns__query_fail(qu
,adns_s_norecurse
);
248 adns__diag(ads
,serv
,qu
,"server claims to do recursion, but gave us a referral");
249 adns__query_fail(qu
,adns_s_invalidresponse
);
254 /* Now, we have some RRs which we wanted. */
256 qu
->answer
->rrs
.untyped
= adns__alloc_interim(qu
,qu
->typei
->rrsz
*wantedrrs
);
257 if (!qu
->answer
->rrs
.untyped
) { adns__query_fail(qu
,adns_s_nomemory
); return; }
261 rrsdata
= qu
->answer
->rrs
.bytes
;
268 pai
.nsstart
= nsstart
;
269 pai
.nscount
= nscount
;
270 pai
.arcount
= arcount
;
273 for (rri
=0, nrrs
=0; rri
<ancount
; rri
++) {
274 st
= adns__findrr(qu
,serv
, dgram
,dglen
,&cbyte
,
275 &rrtype
,&rrclass
,&rdlength
,&rdstart
,
277 assert(!st
); assert(rrtype
!= -1);
278 if (rrclass
!= DNS_CLASS_IN
||
279 rrtype
!= (qu
->typei
->type
& adns__rrt_typemask
) ||
282 st
= typei
->parse(&pai
, rdstart
,rdstart
+rdlength
, rrsdata
+nrrs
*typei
->rrsz
);
283 if (st
) { adns__query_fail(qu
,st
); return; }
284 if (rdstart
==-1) goto x_truncated
;
287 assert(nrrs
==wantedrrs
);
288 qu
->answer
->nrrs
= nrrs
;
290 /* This may have generated some child queries ... */
291 if (qu
->children
.head
) {
292 qu
->state
= query_child
;
293 LIST_LINK_TAIL(ads
->childw
,qu
);
297 adns__query_done(qu
);
303 adns__diag(ads
,serv
,qu
,"server sent datagram which points outside itself");
304 adns__query_fail(qu
,adns_s_invalidresponse
);
307 qu
->flags
|= adns_qf_usevc
;
311 if (qu
->cname_dgram
) {
312 st
= adns__mkquery_frdgram(qu
->ads
,&qu
->vb
,&qu
->id
,
313 qu
->cname_dgram
, qu
->cname_dglen
, qu
->cname_begin
,
314 qu
->typei
->type
, qu
->flags
);
315 if (st
) { adns__query_fail(qu
,st
); return; }
317 newquery
= realloc(qu
->query_dgram
,qu
->vb
.used
);
318 if (!newquery
) { adns__query_fail(qu
,adns_s_nomemory
); return; }
320 qu
->query_dgram
= newquery
;
321 qu
->query_dglen
= qu
->vb
.used
;
322 memcpy(newquery
,qu
->vb
.buf
,qu
->vb
.used
);
325 adns__reset_cnameonly(qu
);
326 adns__query_udp(qu
,now
);