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.
25 static void cname_recurse(adns_query qu
, adns_queryflags xflags
) {
26 assert(!"cname not implemented"); /* FIXME */
29 void adns__procdgram(adns_state ads
, const byte
*dgram
, int dglen
,
30 int serv
, struct timeval now
) {
31 int cbyte
, rrstart
, wantedrrs
, rri
, foundsoa
, foundns
, cname_here
;
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
;
35 int anstart
, nsstart
, arstart
;
41 if (dglen
<DNS_HDRSIZE
) {
42 adns__diag(ads
,serv
,0,"received datagram too short for message header (%d)",dglen
);
53 assert(cbyte
== DNS_HDRSIZE
);
65 adns__diag(ads
,serv
,0,"server sent us a query, not a response");
69 adns__diag(ads
,serv
,0,"server sent us unknown opcode %d (wanted 0=QUERY)",opcode
);
73 adns__diag(ads
,serv
,0,"server sent reply without quoting our question");
75 } else if (qdcount
>1) {
76 adns__diag(ads
,serv
,0,"server claimed to answer %d questions with one message",
80 for (qu
= ads
->timew
.head
; qu
; qu
= nqu
) {
82 if (qu
->id
!= id
) continue;
83 if (dglen
< qu
->query_dglen
) continue;
84 if (memcmp(qu
->query_dgram
+DNS_HDRSIZE
,
86 qu
->query_dglen
-DNS_HDRSIZE
))
91 if (ads
->iflags
& adns_if_debug
) {
92 adns__vbuf_init(&tempvb
);
93 adns__debug(ads
,serv
,0,"reply not found, id %02x, query owner %s",
94 id
, adns__diag_domain(ads
,serv
,0,&tempvb
,adns_qf_anyquote
,
95 dgram
,dglen
,DNS_HDRSIZE
));
96 adns__vbuf_free(&tempvb
);
100 anstart
= qu
->query_dglen
;
102 LIST_UNLINK(ads
->timew
,qu
);
103 /* We're definitely going to do something with this query now */
109 case rcode_formaterror
:
110 adns__warn(ads
,serv
,qu
,"server cannot understand our query (Format Error)");
111 adns__query_fail(qu
,adns_s_serverfaulty
);
114 adns__query_fail(qu
,adns_s_servfail
);
117 adns__warn(ads
,serv
,qu
,"server claims not to implement our query");
118 adns__query_fail(qu
,adns_s_notimplemented
);
121 adns__warn(ads
,serv
,qu
,"server refused our query");
122 adns__query_fail(qu
,adns_s_refused
);
125 adns__warn(ads
,serv
,qu
,"server gave unknown response code %d",rcode
);
126 adns__query_fail(qu
,adns_s_reasonunknown
);
130 /* Now, take a look at the answer section, and see if it is complete.
131 * If it has any CNAMEs we stuff them in the answer.
135 for (rri
= 0; rri
<ancount
; rri
++) {
137 st
= adns__findrr(qu
,serv
, dgram
,dglen
,&cbyte
,
138 &rrtype
,&rrclass
,&rdlength
,&rdstart
,
140 if (st
) { adns__query_fail(qu
,st
); return; }
141 if (rrtype
== -1) goto x_truncated
;
143 if (rrclass
!= DNS_CLASS_IN
) {
144 adns__diag(ads
,serv
,qu
,"ignoring answer RR with wrong class %d (expected IN=%d)",
145 rrclass
,DNS_CLASS_IN
);
149 if (ads
->iflags
& adns_if_debug
) {
150 adns__debug(ads
,serv
,qu
,"ignoring RR with an unexpected owner %s",
151 adns__diag_domain(ads
,serv
,qu
, &qu
->vb
,qu
->flags
,
152 dgram
,dglen
,rrstart
));
156 if (rrtype
== adns_r_cname
&&
157 (qu
->typei
->type
& adns__rrt_typemask
) != adns_r_cname
) {
158 if (!qu
->cname_dgram
) { /* Ignore second and subsequent CNAMEs */
159 qu
->cname_dgram
= adns__alloc_mine(qu
,dglen
);
160 if (!qu
->cname_dgram
) return;
161 qu
->cname_begin
= rdstart
;
162 qu
->cname_dglen
= dglen
;
163 st
= adns__parse_domain(ads
,serv
,qu
, &qu
->vb
,qu
->flags
,
164 dgram
,dglen
, &rdstart
,rdstart
+rdlength
);
165 if (!qu
->vb
.used
) goto x_truncated
;
166 if (st
) { adns__query_fail(qu
,st
); return; }
167 l
= strlen(qu
->vb
.buf
)+1;
168 qu
->answer
->cname
= adns__alloc_interim(qu
,l
);
169 if (!qu
->answer
->cname
) return;
170 memcpy(qu
->answer
->cname
,qu
->vb
.buf
,l
);
172 /* If we find the answer section truncated after this point we restart
173 * the query at the CNAME; if beforehand then we obviously have to use
174 * TCP. If there is no truncation we can use the whole answer if
175 * it contains the relevant info.
178 adns__debug(ads
,serv
,qu
,"ignoring duplicate CNAME (%s, as well as %s)",
179 adns__diag_domain(ads
,serv
,qu
, &qu
->vb
,qu
->flags
,
180 dgram
,dglen
,rdstart
),
183 } else if (rrtype
== (qu
->typei
->type
& adns__rrt_typemask
)) {
186 adns__debug(ads
,serv
,qu
,"ignoring answer RR with irrelevant type %d",rrtype
);
190 /* If we got here then the answer section is intact. */
194 /* Oops, NODATA or NXDOMAIN or perhaps a referral (which would be a problem) */
196 if (rcode
== rcode_nxdomain
) {
197 adns__query_fail(qu
,adns_s_nxdomain
);
201 /* RFC2308: NODATA has _either_ a SOA _or_ _no_ NS records in authority section */
202 foundsoa
= 0; foundns
= 0;
203 for (rri
= 0; rri
<nscount
; rri
++) {
205 st
= adns__findrr(qu
,serv
, dgram
,dglen
,&cbyte
,
206 &rrtype
,&rrclass
,&rdlength
,&rdstart
, 0);
207 if (st
) { adns__query_fail(qu
,st
); return; }
208 if (rrtype
==-1) goto x_truncated
;
209 if (rrclass
!= DNS_CLASS_IN
) {
210 adns__diag(ads
,serv
,qu
,
211 "ignoring authority RR with wrong class %d (expected IN=%d)",
212 rrclass
,DNS_CLASS_IN
);
215 if (rrtype
== adns_r_soa_raw
) { foundsoa
= 1; break; }
216 else if (rrtype
== adns_r_ns_raw
) { foundns
= 1; }
219 if (foundsoa
|| !foundns
) {
220 /* Aha ! A NODATA response, good. */
221 adns__query_fail(qu
,adns_s_nodata
);
225 /* Now what ? No relevant answers, no SOA, and at least some NS's.
226 * Looks like a referral. Just one last chance ... if we came across
227 * a CNAME in this datagram then we should probably do our own CNAME
228 * lookup now in the hope that we won't get a referral again.
230 if (cname_here
) { cname_recurse(qu
,0); return; }
232 /* Bloody hell, I thought we asked for recursion ? */
234 adns__diag(ads
,serv
,qu
,"server thinks we didn't ask for recursive lookup");
237 adns__diag(ads
,serv
,qu
,"server is not willing to do recursive lookups for us");
238 adns__query_fail(qu
,adns_s_norecurse
);
240 adns__diag(ads
,serv
,qu
,"server claims to do recursion, but gave us a referral");
241 adns__query_fail(qu
,adns_s_serverfaulty
);
246 /* Now, we have some RRs which we wanted. */
248 qu
->answer
->rrs
.untyped
= adns__alloc_interim(qu
,qu
->typei
->rrsz
*wantedrrs
);
249 if (!qu
->answer
->rrs
.untyped
) return;
253 for (rri
=0; rri
<ancount
; rri
++) {
254 st
= adns__findrr(qu
,serv
, dgram
,dglen
,&cbyte
,
255 &rrtype
,&rrclass
,&rdlength
,&rdstart
,
257 assert(!st
); assert(rrtype
!= -1);
258 if (rrclass
!= DNS_CLASS_IN
||
259 rrtype
!= (qu
->typei
->type
& adns__rrt_typemask
) ||
262 assert(qu
->answer
->nrrs
<wantedrrs
);
263 st
= qu
->typei
->parse(qu
,serv
,
264 dgram
,dglen
, rdstart
,rdstart
+rdlength
,
265 qu
->answer
->rrs
.bytes
+qu
->answer
->nrrs
*qu
->typei
->rrsz
);
266 if (st
) { adns__query_fail(qu
,st
); return; }
267 if (rdstart
==-1) goto x_truncated
;
271 /* This may have generated some child queries ... */
272 if (qu
->children
.head
) {
273 qu
->state
= query_child
;
274 LIST_LINK_TAIL(ads
->childw
,qu
);
278 adns__query_done(qu
);
283 adns__diag(ads
,serv
,qu
,"server sent datagram which points outside itself");
284 adns__query_fail(qu
,adns_s_serverfaulty
);
287 if (qu
->cname_dgram
) { cname_recurse(qu
,adns_qf_usevc
); return; }
288 adns__reset_cnameonly(qu
);
289 qu
->flags
|= adns_qf_usevc
;
290 adns__query_udp(qu
,now
);