-/**/
+/*
+ * reply.c
+ * - main handling and parsing routine for received datagrams
+ */
+/*
+ * This file is
+ * Copyright (C) 1997-2000 Ian Jackson <ian@davenant.greenend.org.uk>
+ *
+ * It is part of adns, which is
+ * Copyright (C) 1997-2000 Ian Jackson <ian@davenant.greenend.org.uk>
+ * Copyright (C) 1999-2000 Tony Finch <dot@dotat.at>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
-#include "internal.h"
-
-typedef enum {
- rcode_noerror,
- rcode_formaterror,
- rcode_servfail,
- rcode_nxdomain,
- rcode_notimp,
- rcode_refused
-} dns_rcode;
+#include <stdlib.h>
-#define GETIL_B(cb) (dgram[*(cb)++])
-#define GET_B(cb,tv) ((tv)= GETIL_B((cb)))
-#define GET_W(cb,tv) ((tv)=0, (tv)|=(GETIL_B((cb))<<8), (tv)|=GETIL_B(cb), (tv))
-
-static void vbuf__append_quoted1035(vbuf *vb, const byte *buf, int len) {
- char qbuf[10];
- int i;
-
- while (len) {
- qbuf[0]= 0;
- for (i=0; i<len; i++) {
- ch= buf[i];
- if (ch == '.' || ch == '"' || ch == '(' || ch == ')' ||
- ch == '@' || ch == ';' || ch == '$') {
- sprintf(qbuf,"\\%c",ch);
- break;
- } else if (ch <= ' ' || ch >= 127) {
- sprintf(qbuf,"\\%03o",ch);
- break;
- }
- }
- if (!adns__vbuf_append(vb,buf,i) || !adns__vbuf_append(vb,qbuf,strlen(qbuf)))
- return adns_s_nolocalmem;
- buf+= i; len-= i;
- }
-}
-
-static adns_status get_domain_perm(adns_state ads, adns_query qu, int serv,
- const byte *dgram, int dglen,
- int *cbyte_io, int max, char **domain_r) {
- /* Returns 0 for OK (*domain_r set) or truncated (*domain_r null)
- * or any other adns_s_* value.
- */
- int cbyte, sused, lablen;
-
- /* If we follow a pointer we set cbyte_io to 0 to indicate that
- * we've lost our original starting and ending points; we don't
- * put the end of the pointed-to thing into the original *cbyte_io.
- */
- cbyte= *cbyte_io;
- sused= qu->ans.used;
- *domain_r= 0;
- for (;;) {
- if (cbyte>=max) goto x_truncated;
- lablen= GET_B(cbyte);
- if (!lablen) break;
- if (lablen&0x0c000) {
- if ((lablen&0x0c000) != 0x0c0000) return adns_s_unknownreply;
- if (cbyte_io) { *cbyte_io= cbyte; cbyte_io= 0; }
- cbyte= (lablen&0x3fff) + DNS_HDR_SIZE;
- max= dglen;
- continue;
- }
- if (cbyte+lablen>=max) bgoto x_truncated;
- if (qu->ans.used != sused)
- if (!adns__vbuf_append(&qu->ans,".",1)) return adns_s_nolocalmem;
- if (qu->flags & adns_qf_anyquote) {
- if (!vbuf__append_quoted1035(&qu->ans,dgram+cbyte,lablen))
- return adns_s_nolocalmem;
- } else {
- if (!ctype_isalpha(dgram[cbyte])) return adns_s_invaliddomain;
- for (i= cbyte+1; i<cbyte+lablen; i++) {
- ch= dgram[cbyte];
- if (ch != '-' && !ctype_isalpha(ch) && !ctype_isdigit(ch))
- return adns_s_invaliddomain;
- }
- if (!adns__vbuf_append(&qu->ans,dgram+cbyte,lablen))
- return adns_s_nolocalmem;
- }
- }
- if (cbyte_io) *cbyte_io= cbyte;
- if (!adns__vbuf_append(&qu->ans,"",1)) return adns_s_nolocalmem;
- *domain_r= qu->ans.buf+sused;
- return adns_s_ok;
-
- x_truncated:
- return cbyte_io ? -1 : adns_s_serverfaulty;
-}
+#include "internal.h"
-static adns_status get_domain_temp(adns_state ads, adns_query qu, int serv,
- const byte *dgram, int dglen,
- int *cbyte_io, int max, char **domain_r) {
- int sused;
+void adns__procdgram(adns_state ads, const byte *dgram, int dglen,
+ int serv, int viatcp, struct timeval now) {
+ int cbyte, rrstart, wantedrrs, rri, foundsoa, foundns, cname_here;
+ int id, f1, f2, qdcount, ancount, nscount, arcount;
+ int flg_ra, flg_rd, flg_tc, flg_qr, opcode;
+ int rrtype, rrclass, rdlength, rdstart;
+ int anstart, nsstart, arstart;
+ int ownermatched, l, nrrs;
+ unsigned long ttl, soattl;
+ const typeinfo *typei;
+ adns_query qu, nqu;
+ dns_rcode rcode;
adns_status st;
-
- sused= qu->ans.used;
- st= get_domain_perm(ads,qu,serv,dgram,dglen,cbyte_io,max,domain_r);
- qu->ans.used= sused;
- return st;
-}
-
-/* fixme: sensible comparison of owners */
-
-static adns_status get_rr_temp(adns_state ads, adns_query qu, int serv,
- const byte *dgram, int dglen,
- int *cbyte_io,
- int *type_r, int *class_r, int *rdlen_r, int *rdstart_r,
- char **owner_r) {
- int cbyte, tmp, rdlen;
-
- cbyte= *cbyte_io;
- st= get_domain_temp(ads,qu,serv,dgram,dglen,&cbyte,dglen,owner_r);
- if (st) return st;
+ vbuf tempvb;
+ byte *newquery, *rrsdata;
+ parseinfo pai;
- if (cbyte+10>len) goto x_truncated;
- GET_W(cbyte,tmp); if (type_r) *type_r= tmp;
- GET_W(cbyte,tmp); if (class_r) *class_r= tmp;
- cbyte+= 4; /* we skip the TTL */
- GET_W(cbyte,rdlen); if (rdlen_r) *rdlen_r= tmp;
- if (rdstart_r) *rdstart_r= cbyte;
- cbyte+= rdlen;
- if (cbyte>dglen) goto x_truncated;
- *cbyte_io= cbyte;
- return adns_s_ok;
-
- x_truncated:
- *owner_r= 0; return 0;;
-}
-
-void adns__procdgram(adns_state ads, const byte *dgram, int dglen, int serv) {
- int cbyte, anstart, rrstart, lablen, wantedrrs, get_t;
-
- cbyte= 0;
-
- if (dglen<DNS_HDR_SIZE) {
- adns__diag(ads,serv,"received datagram too short for message header (%d)",len);
+ if (dglen<DNS_HDRSIZE) {
+ adns__diag(ads,serv,0,"received datagram"
+ " too short for message header (%d)",dglen);
return;
}
+ cbyte= 0;
GET_W(cbyte,id);
GET_B(cbyte,f1);
GET_B(cbyte,f2);
GET_W(cbyte,ancount);
GET_W(cbyte,nscount);
GET_W(cbyte,arcount);
- assert(cbyte == DNS_HDR_SIZE);
+ assert(cbyte == DNS_HDRSIZE);
- if (f1&0x80) {
- adns__diag(ads,serv,"server sent us a query, not a response");
- return;
- }
- if (f1&0x70) {
- adns__diag(ads,serv,"server sent us unknown opcode %d (wanted 0=QUERY)",
- (f1>>4)&0x70);
- return;
- }
- if (!qdcount) {
- adns__diag(ads,serv,"server sent reply without quoting our question");
- return;
- } else if (qdcount>1) {
- adns__diag(ads,serv,"server claimed to answer %d questions with one message",
- qdcount);
- return;
- }
- for (qu= ads->timew; qu= nqu; qu++) {
- nqu= qu->next;
- if (qu->id != id) continue;
- if (len < qu->querylen) continue;
- if (memcmp(qu->querymsg+DNSHDRSIZE,dgram+DNSHDRSIZE,qu->querylen-DNSHDRSIZE))
- continue;
- break;
- }
- anstart= qu->querylen;
- if (!qu) {
- adns__debug(ads,serv,"reply not found (id=%02x)",id);
+ flg_qr= f1&0x80;
+ opcode= (f1&0x78)>>3;
+ flg_tc= f1&0x02;
+ flg_rd= f1&0x01;
+ flg_ra= f2&0x80;
+ rcode= (f2&0x0f);
+
+ cname_here= 0;
+
+ if (!flg_qr) {
+ adns__diag(ads,serv,0,"server sent us a query, not a response");
return;
}
- if (!(f1&0x01)) {
- adns__diag(ads,serv,"server thinks we didn't ask for recursive lookup");
- adns__query_fail(ads,qu,adns_s_serverfaulty);
+ if (opcode) {
+ adns__diag(ads,serv,0,"server sent us unknown opcode"
+ " %d (wanted 0=QUERY)",opcode);
return;
}
- rcode= (f1&0x0f);
+ qu= 0;
+ /* See if we can find the relevant query, or leave qu=0 otherwise ... */
+
+ if (qdcount == 1) {
+ for (qu= viatcp ? ads->tcpw.head : ads->udpw.head; qu; qu= nqu) {
+ nqu= qu->next;
+ if (qu->id != id) continue;
+ if (dglen < qu->query_dglen) continue;
+ if (memcmp(qu->query_dgram+DNS_HDRSIZE,
+ dgram+DNS_HDRSIZE,
+ qu->query_dglen-DNS_HDRSIZE))
+ continue;
+ if (viatcp) {
+ assert(qu->state == query_tcpw);
+ } else {
+ assert(qu->state == query_tosend);
+ if (!(qu->udpsent & (1<<serv))) continue;
+ }
+ break;
+ }
+ if (qu) {
+ /* We're definitely going to do something with this query now */
+ if (viatcp) LIST_UNLINK(ads->tcpw,qu);
+ else LIST_UNLINK(ads->udpw,qu);
+ }
+ }
+
+ /* If we're going to ignore the packet, we return as soon as we have
+ * failed the query (if any) and printed the warning message (if
+ * any).
+ */
switch (rcode) {
case rcode_noerror:
case rcode_nxdomain:
break;
case rcode_formaterror:
- adns__warn(ads,serv,"server cannot understand our query (Format Error)");
- adns__query_fail(ads,qu,adns_s_serverfaulty);
+ adns__warn(ads,serv,qu,"server cannot understand our query"
+ " (Format Error)");
+ if (qu) adns__query_fail(qu,adns_s_rcodeformaterror);
return;
- case rcode_servfail;
- adns__query_fail(ads,qu,adns_s_serverfailure);
+ case rcode_servfail:
+ if (qu) adns__query_fail(qu,adns_s_rcodeservfail);
+ else adns__debug(ads,serv,qu,"server failure on unidentifiable query");
return;
case rcode_notimp:
- adns__warn(ads,serv,"server claims not to implement our query");
- adns__query_fail(ads,qu,adns_s_notimplemented);
+ adns__warn(ads,serv,qu,"server claims not to implement our query");
+ if (qu) adns__query_fail(qu,adns_s_rcodenotimplemented);
return;
case rcode_refused:
- adns__warn(ads,serv,"server refused our query");
- adns__query_fail(ads,qu,adns_s_refused);
+ adns__debug(ads,serv,qu,"server refused our query");
+ if (qu) adns__query_fail(qu,adns_s_rcoderefused);
return;
default:
- adns__warn(ads,serv,"server gave unknown response code %d",rcode);
- adns__query_fail(ads,qu,adns_s_reasonunknown);
+ adns__warn(ads,serv,qu,"server gave unknown response code %d",rcode);
+ if (qu) adns__query_fail(qu,adns_s_rcodeunknown);
return;
}
+ if (!qu) {
+ if (!qdcount) {
+ adns__diag(ads,serv,0,"server sent reply without quoting our question");
+ } else if (qdcount>1) {
+ adns__diag(ads,serv,0,"server claimed to answer %d"
+ " questions with one message", qdcount);
+ } else if (ads->iflags & adns_if_debug) {
+ adns__vbuf_init(&tempvb);
+ adns__debug(ads,serv,0,"reply not found, id %02x, query owner %s",
+ id, adns__diag_domain(ads,serv,0,&tempvb,
+ dgram,dglen,DNS_HDRSIZE));
+ adns__vbuf_free(&tempvb);
+ }
+ return;
+ }
+
+ /* We're definitely going to do something with this packet and this
+ * query now. */
+
+ anstart= qu->query_dglen;
+ arstart= -1;
+
/* Now, take a look at the answer section, and see if it is complete.
* If it has any CNAMEs we stuff them in the answer.
*/
wantedrrs= 0;
+ cbyte= anstart;
for (rri= 0; rri<ancount; rri++) {
rrstart= cbyte;
- st= get_rr_temp(ads,qu,serv,
- dgram,dglen,
- &cbyte,
- &rrtype,&rrclass,&rdlength,&cowner);
- if (st) adns__query_fail(ads,qu,st);
+ st= adns__findrr(qu,serv, dgram,dglen,&cbyte,
+ &rrtype,&rrclass,&ttl, &rdlength,&rdstart,
+ &ownermatched);
+ if (st) { adns__query_fail(qu,st); return; }
+ if (rrtype == -1) goto x_truncated;
+
if (rrclass != DNS_CLASS_IN) {
- adns__diag(ads,serv,"ignoring RR with wrong class %d (expected IN=%d)",
- rrclass,DNS_CLASS_IN);
+ adns__diag(ads,serv,qu,"ignoring answer RR with wrong class %d"
+ " (expected IN=%d)", rrclass,DNS_CLASS_IN);
continue;
}
- if (strcmp_quoted1035(cowner, qu->cname ? qu->cname : qu->owner)) {
- adns__debug(ads,serv,"ignoring answer RR with irrelevant owner \"%s\"",cowner);
+ if (!ownermatched) {
+ if (ads->iflags & adns_if_debug) {
+ adns__debug(ads,serv,qu,"ignoring RR with an unexpected owner %s",
+ adns__diag_domain(ads,serv,qu, &qu->vb,
+ dgram,dglen,rrstart));
+ }
continue;
}
- if (!qu->cname &&
- (qu->type & adns__rrt_typemask) != adns_cname &&
- rrtype == adns_cname) { /* Ignore second and subsequent CNAMEs */
- qu->cname= get_domain_perm(ads,qu,dgram,len,rdstart,rdstart+rdlength);
+ if (rrtype == adns_r_cname &&
+ (qu->answer->type & adns_rrt_typemask) != adns_r_cname) {
+ if (qu->flags & adns_qf_cname_forbid) {
+ adns__query_fail(qu,adns_s_prohibitedcname);
+ return;
+ } else if (qu->cname_dgram) { /* Ignore second and subsequent CNAME(s) */
+ adns__debug(ads,serv,qu,"allegedly canonical name %s"
+ " is actually alias for %s", qu->answer->cname,
+ adns__diag_domain(ads,serv,qu, &qu->vb,
+ dgram,dglen,rdstart));
+ adns__query_fail(qu,adns_s_prohibitedcname);
+ return;
+ } else if (wantedrrs) { /* Ignore CNAME(s) after RR(s). */
+ adns__debug(ads,serv,qu,"ignoring CNAME (to %s) coexisting with RR",
+ adns__diag_domain(ads,serv,qu, &qu->vb,
+ dgram,dglen,rdstart));
+ } else {
+ qu->cname_begin= rdstart;
+ qu->cname_dglen= dglen;
+ st= adns__parse_domain(ads,serv,qu, &qu->vb,
+ qu->flags & adns_qf_quotefail_cname
+ ? 0 : pdf_quoteok,
+ dgram,dglen, &rdstart,rdstart+rdlength);
+ if (!qu->vb.used) goto x_truncated;
+ if (st) { adns__query_fail(qu,st); return; }
+ l= strlen(qu->vb.buf)+1;
+ qu->answer->cname= adns__alloc_preserved(qu,l);
+ if (!qu->answer->cname) {
+ adns__query_fail(qu,adns_s_nomemory);
+ return;
+ }
+
+ qu->cname_dgram= adns__alloc_mine(qu,dglen);
+ memcpy(qu->cname_dgram,dgram,dglen);
+
+ memcpy(qu->answer->cname,qu->vb.buf,l);
+ cname_here= 1;
+ adns__update_expires(qu,ttl,now);
/* If we find the answer section truncated after this point we restart
- * the query at the CNAME; otherwise we can use it as-is.
+ * the query at the CNAME; if beforehand then we obviously have to use
+ * TCP. If there is no truncation we can use the whole answer if
+ * it contains the relevant info.
*/
- } else if (rrtype == (qu->type & adns__rrt_typemask)) {
+ }
+ } else if (rrtype == (qu->answer->type & adns_rrt_typemask)) {
wantedrrs++;
} else {
- adns__debug(ads,serv,"ignoring answer RR with irrelevant type %d",rrtype);
+ adns__debug(ads,serv,qu,"ignoring answer RR"
+ " with irrelevant type %d",rrtype);
}
}
- /* If we got here then the answer section is intact. */
+ /* We defer handling truncated responses here, in case there was a CNAME
+ * which we could use.
+ */
+ if (flg_tc) goto x_truncated;
+
nsstart= cbyte;
if (!wantedrrs) {
- /* Oops, NODATA or NXDOMAIN or perhaps a referral (which would be a problem) */
+ /* Oops, NODATA or NXDOMAIN or perhaps a referral
+ * (which would be a problem) */
+
+ /* RFC2308: NODATA has _either_ a SOA _or_ _no_ NS records
+ * in authority section */
+ foundsoa= 0; soattl= 0; foundns= 0;
+ for (rri= 0; rri<nscount; rri++) {
+ rrstart= cbyte;
+ st= adns__findrr(qu,serv, dgram,dglen,&cbyte,
+ &rrtype,&rrclass,&ttl, &rdlength,&rdstart, 0);
+ if (st) { adns__query_fail(qu,st); return; }
+ if (rrtype==-1) goto x_truncated;
+ if (rrclass != DNS_CLASS_IN) {
+ adns__diag(ads,serv,qu,
+ "ignoring authority RR with wrong class %d"
+ " (expected IN=%d)", rrclass,DNS_CLASS_IN);
+ continue;
+ }
+ if (rrtype == adns_r_soa_raw) { foundsoa= 1; soattl= ttl; break; }
+ else if (rrtype == adns_r_ns_raw) { foundns= 1; }
+ }
if (rcode == rcode_nxdomain) {
- adnns__query_finish(ads,qu,adns_s_nxdomain);
+ /* We still wanted to look for the SOA so we could find the TTL. */
+ adns__update_expires(qu,soattl,now);
+
+ if (qu->flags & adns_qf_search && !qu->cname_dgram) {
+ adns__search_next(ads,qu,now);
+ } else {
+ adns__query_fail(qu,adns_s_nxdomain);
+ }
return;
}
- /* RFC2308: NODATA has _either_ a SOA _or_ _no_ NS records in authority section */
- for (rri= 0; rri<nscount; rri++) {
-
+ if (foundsoa || !foundns) {
+ /* Aha ! A NODATA response, good. */
+ adns__update_expires(qu,soattl,now);
+ adns__query_fail(qu,adns_s_nodata);
+ return;
}
+
+ /* Now what ? No relevant answers, no SOA, and at least some NS's.
+ * Looks like a referral. Just one last chance ... if we came across
+ * a CNAME in this datagram then we should probably do our own CNAME
+ * lookup now in the hope that we won't get a referral again.
+ */
+ if (cname_here) goto x_restartquery;
+
+ /* Bloody hell, I thought we asked for recursion ? */
+ if (!flg_ra) {
+ adns__diag(ads,serv,qu,"server is not willing"
+ " to do recursive lookups for us");
+ adns__query_fail(qu,adns_s_norecurse);
} else {
-
-
- if (!(f2&0x80)) {
- adns__diag(ads,serv,"server is not willing to do recursive lookups for us");
- adns__query_fail(ads,qu,adns_s_norecurse);
+ if (!flg_rd)
+ adns__diag(ads,serv,qu,"server thinks"
+ " we didn't ask for recursive lookup");
+ else
+ adns__debug(ads,serv,qu,"server claims to do recursion,"
+ " but gave us a referral");
+ adns__query_fail(qu,adns_s_invalidresponse);
+ }
return;
}
-
- ) {
- if (type
- if (cbyte+lab
- if (anstart > dgend) { truncated(ads,qu,f1); return; }
+ /* Now, we have some RRs which we wanted. */
+
+ qu->answer->rrs.untyped= adns__alloc_interim(qu,qu->typei->rrsz*wantedrrs);
+ if (!qu->answer->rrs.untyped) {
+ adns__query_fail(qu,adns_s_nomemory);
+ return;
+ }
+
+ typei= qu->typei;
+ cbyte= anstart;
+ rrsdata= qu->answer->rrs.bytes;
+
+ pai.ads= qu->ads;
+ pai.qu= qu;
+ pai.serv= serv;
+ pai.dgram= dgram;
+ pai.dglen= dglen;
+ pai.nsstart= nsstart;
+ pai.nscount= nscount;
+ pai.arcount= arcount;
+ pai.now= now;
+
+ for (rri=0, nrrs=0; rri<ancount; rri++) {
+ st= adns__findrr(qu,serv, dgram,dglen,&cbyte,
+ &rrtype,&rrclass,&ttl, &rdlength,&rdstart,
+ &ownermatched);
+ assert(!st); assert(rrtype != -1);
+ if (rrclass != DNS_CLASS_IN ||
+ rrtype != (qu->answer->type & adns_rrt_typemask) ||
+ !ownermatched)
+ continue;
+ adns__update_expires(qu,ttl,now);
+ st= typei->parse(&pai, rdstart,rdstart+rdlength, rrsdata+nrrs*typei->rrsz);
+ if (st) { adns__query_fail(qu,st); return; }
+ if (rdstart==-1) goto x_truncated;
+ nrrs++;
}
- for
+ assert(nrrs==wantedrrs);
+ qu->answer->nrrs= nrrs;
- /* Look for CNAMEs in the answer section */
+ /* This may have generated some child queries ... */
+ if (qu->children.head) {
+ qu->state= query_childw;
+ LIST_LINK_TAIL(ads->childw,qu);
+ return;
+ }
+ adns__query_done(qu);
+ return;
+ x_truncated:
+
+ if (!flg_tc) {
+ adns__diag(ads,serv,qu,"server sent datagram which points outside itself");
+ adns__query_fail(qu,adns_s_invalidresponse);
+ return;
}
+ qu->flags |= adns_qf_usevc;
+ x_restartquery:
+ if (qu->cname_dgram) {
+ st= adns__mkquery_frdgram(qu->ads,&qu->vb,&qu->id,
+ qu->cname_dgram,qu->cname_dglen,qu->cname_begin,
+ qu->answer->type, qu->flags);
+ if (st) { adns__query_fail(qu,st); return; }
- adns__diag(ads,serv,"server refused our query");
-
- case rcode_
+ newquery= realloc(qu->query_dgram,qu->vb.used);
+ if (!newquery) { adns__query_fail(qu,adns_s_nomemory); return; }
- case 0: /* NOERROR
- break;
- case 1: /* Format error */
- case 3: /* Name Error */
-
- qr= f1&0x80;
+ qu->query_dgram= newquery;
+ qu->query_dglen= qu->vb.used;
+ memcpy(newquery,qu->vb.buf,qu->vb.used);
+ }
-
- adns__diag(ads,serv,"received datagram size %d",len);
-
+ if (qu->state == query_tcpw) qu->state= query_tosend;
+ qu->retries= 0;
+ adns__reset_preserved(qu);
+ adns__query_send(qu,now);
}
~mdw / adns / blobdiff