Only accept a reply from the subset of servers we sent the query.

[adns] / src / reply.c

diff --git a/src/reply.c b/src/reply.c
index 39337e881de251d822ba20ad35bd3c26e37186c3..8da0bf2a648e8ff18ba5d3cecc59ddfa93eca91c 100644 (file)
--- a/src/reply.c
+++ b/src/reply.c
@@ -1,29 +1,52 @@
-/**/
+/*
+ * reply.c
+ * - main handling and parsing routine for received datagrams
+ */
+/*
+ *  This file is part of adns, which is Copyright (C) 1997-1999 Ian Jackson
+ *  
+ *  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"
+#include <stdlib.h>
+#include <string.h>

 
 

-static void cname_recurse(adns_state ads, adns_query qu, adns_queryflags xflags) {
-  abort(); /* FIXME */
-}
+#include "internal.h"

     
 void adns__procdgram(adns_state ads, const byte *dgram, int dglen,
     
 void adns__procdgram(adns_state ads, const byte *dgram, int dglen,

-                    int serv, struct timeval now) {
-  int cbyte, rrstart, wantedrrs, rri, foundsoa, foundns;
-  int id, f1, f2, qdcount, ancount, nscount, arcount, flg_ra, flg_tc;
-  int rrtype, rrclass, rdlength, rdstart, ownermatched, ownerstart;
+                    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 anstart, nsstart, arstart;

-  int currentrrs;
+  int ownermatched, l, nrrs;
+  unsigned long ttl, soattl;
+  const typeinfo *typei;

   adns_query qu, nqu;
   dns_rcode rcode;
   adns_status st;
   adns_query qu, nqu;
   dns_rcode rcode;
   adns_status st;

-  adns_answer *ans;
-
-  cbyte= 0;
+  vbuf tempvb;
+  byte *newquery, *rrsdata;
+  parseinfo pai;

   
   if (dglen<DNS_HDRSIZE) {
   
   if (dglen<DNS_HDRSIZE) {

-    adns__diag(ads,serv,"received datagram too short for message header (%d)",dglen);
+    adns__diag(ads,serv,0,"received datagram too short for message header (%d)",dglen);

     return;
   }
     return;
   }

+  cbyte= 0;

   GET_W(cbyte,id);
   GET_B(cbyte,f1);
   GET_B(cbyte,f2);
   GET_W(cbyte,id);
   GET_B(cbyte,f1);
   GET_B(cbyte,f2);


@@ -33,73 +56,84 @@ void adns__procdgram(adns_state ads, const byte *dgram, int dglen,
   GET_W(cbyte,arcount);
   assert(cbyte == DNS_HDRSIZE);
 
   GET_W(cbyte,arcount);
   assert(cbyte == DNS_HDRSIZE);
 

-  flg_tc= f1&0x20;
+  flg_qr= f1&0x80;
+  opcode= (f1&0x78)>>3;
+  flg_tc= f1&0x02;
+  flg_rd= f1&0x01;

   flg_ra= f2&0x80;
   flg_ra= f2&0x80;

+  rcode= (f2&0x0f);

 
 

-  if (f1&0x80) {
-    adns__diag(ads,serv,"server sent us a query, not a response");
+  cname_here= 0;
+  
+  if (!flg_qr) {
+    adns__diag(ads,serv,0,"server sent us a query, not a response");

     return;
   }
     return;
   }

-  if (f1&0x70) {
-    adns__diag(ads,serv,"server sent us unknown opcode %d (wanted 0=QUERY)",
-              (f1>>4)&0x70);
+  if (opcode) {
+    adns__diag(ads,serv,0,"server sent us unknown opcode %d (wanted 0=QUERY)",opcode);

     return;
   }
   if (!qdcount) {
     return;
   }
   if (!qdcount) {

-    adns__diag(ads,serv,"server sent reply without quoting our question");
+    adns__diag(ads,serv,0,"server sent reply without quoting our question");

     return;
   } else if (qdcount>1) {
     return;
   } else if (qdcount>1) {

-    adns__diag(ads,serv,"server claimed to answer %d questions with one message",
+    adns__diag(ads,serv,0,"server claimed to answer %d questions with one message",

               qdcount);
     return;
   }
   for (qu= ads->timew.head; qu; qu= nqu) {
     nqu= qu->next;
     if (qu->id != id) continue;
               qdcount);
     return;
   }
   for (qu= ads->timew.head; qu; qu= nqu) {
     nqu= qu->next;
     if (qu->id != id) continue;

-    if (dglen < qu->querylen) continue;
-    if (memcmp(qu->querymsg+DNS_HDRSIZE,dgram+DNS_HDRSIZE,qu->querylen-DNS_HDRSIZE))
+    if (dglen < qu->query_dglen) continue;
+    if (memcmp(qu->query_dgram+DNS_HDRSIZE,
+              dgram+DNS_HDRSIZE,
+              qu->query_dglen-DNS_HDRSIZE))

       continue;
       continue;

+    if (viatcp) {
+      if (qu->state != query_tcpsent) continue;
+    } else {
+      if (qu->state != query_tosend) continue;
+      if (!(qu->udpsent & (1<<serv))) continue;
+    }

     break;
   }
     break;
   }

-  assert(qu->cnameoff == -1);
-  anstart= qu->querylen;

   if (!qu) {
   if (!qu) {

-    adns__debug(ads,serv,"reply not found (id=%02x)",id);
+    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;
   }
     return;
   }

+  anstart= qu->query_dglen;
+  arstart= -1;

 
   LIST_UNLINK(ads->timew,qu);
   /* We're definitely going to do something with this query now */
   
 
   LIST_UNLINK(ads->timew,qu);
   /* We're definitely going to do something with this query now */
   

-  if (!(f1&0x01)) {
-    adns__diag(ads,serv,"server thinks we didn't ask for recursive lookup");
-    adns__query_fail(ads,qu,adns_s_serverfaulty);
-    return;
-  }
-
-  rcode= (f1&0x0f);

   switch (rcode) {
   case rcode_noerror:
   case rcode_nxdomain:
     break;
   case rcode_formaterror:
   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)");
+    adns__query_fail(qu,adns_s_rcodeformaterror);

     return;
   case rcode_servfail:
     return;
   case rcode_servfail:

-    adns__query_fail(ads,qu,adns_s_servfail);
+    adns__query_fail(qu,adns_s_rcodeservfail);

     return;
   case rcode_notimp:
     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");
+    adns__query_fail(qu,adns_s_rcodenotimplemented);

     return;
   case rcode_refused:
     return;
   case rcode_refused:

-    adns__warn(ads,serv,"server refused our query");
-    adns__query_fail(ads,qu,adns_s_refused);
+    adns__warn(ads,serv,qu,"server refused our query");
+    adns__query_fail(qu,adns_s_rcoderefused);

     return;
   default:
     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);
+    adns__query_fail(qu,adns_s_rcodeunknown);

     return;
   }
 
     return;
   }
 


@@ -107,130 +141,171 @@ void adns__procdgram(adns_state ads, const byte *dgram, int dglen,
    * If it has any CNAMEs we stuff them in the answer.
    */
   wantedrrs= 0;
    * If it has any CNAMEs we stuff them in the answer.
    */
   wantedrrs= 0;

+  cbyte= anstart;

   for (rri= 0; rri<ancount; rri++) {
     rrstart= cbyte;
   for (rri= 0; rri<ancount; rri++) {
     rrstart= cbyte;

-    if (qu->cnameoff >= 0) {
-      st= adns__get_rr_temp(ads,qu,serv, dgram,dglen,&cbyte,
-                           &rrtype,&rrclass,&rdlength,&rdstart,
-                           dgram,dglen,qu->cnameoff, &ownermatched);
-    } else {
-      st= adns__get_rr_temp(ads,qu,serv, dgram,dglen,&cbyte,
-                           &rrtype,&rrclass,&rdlength,&rdstart,
-                           qu->querymsg,qu->querylen,DNS_HDRSIZE, &ownermatched);
-    }
-    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) {
     if (rrtype == -1) goto x_truncated;
 
     if (rrclass != DNS_CLASS_IN) {

-      adns__diag(ads,serv,"ignoring answer RR with wrong class %d (expected IN=%d)",
+      adns__diag(ads,serv,qu,"ignoring answer RR with wrong class %d (expected IN=%d)",

                 rrclass,DNS_CLASS_IN);
       continue;
     }
     if (!ownermatched) {
       if (ads->iflags & adns_if_debug) {
                 rrclass,DNS_CLASS_IN);
       continue;
     }
     if (!ownermatched) {
       if (ads->iflags & adns_if_debug) {

-       st= adns__get_domain_temp(ads,qu,serv, dgram,dglen,&rrstart,dglen, &ownerstart);
-       if (st)
-         adns__debug(ads,serv, "ignoring RR with an irrelevant owner"
-                     " whose format is bad, code %d",st);
-       else if (ownerstart>=0)
-         adns__debug(ads,serv, "ignoring RR with an irrelevant owner"
-                     " \"%s\"", qu->ans.buf+ownerstart);
-       else
-         adns__debug(ads,serv,"ignoring RR with an irrelevant truncated owner");
+       adns__debug(ads,serv,qu,"ignoring RR with an unexpected owner %s",
+                   adns__diag_domain(ads,serv,qu, &qu->vb, dgram,dglen,rrstart));

       }
       continue;
     }
       }
       continue;
     }

-    if (qu->cnameoff<0 &&
-       (qu->typei->type & adns__rrt_typemask) != adns_r_cname &&
-       rrtype == adns_r_cname) { /* Ignore second and subsequent CNAMEs */
-      st= adns__get_domain_perm(ads,qu,serv, dgram,dglen,
-                               &rdstart,rdstart+rdlength,&qu->cnameoff);
-      if (st) { adns__query_fail(ads,qu,st); return; }
-      if (qu->cnameoff==-1) goto x_truncated;
-      /* If we find the answer section truncated after this point we restart
-       * 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.
-       */
+    if (rrtype == adns_r_cname &&
+       (qu->typei->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 CNAMEs */
+       qu->cname_begin= rdstart;
+       qu->cname_dglen= dglen;
+       st= adns__parse_domain(ads,serv,qu, &qu->vb,
+                              qu->flags & adns_qf_quoteok_cname ? pdf_quoteok : 0,
+                              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; 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 {
+       adns__debug(ads,serv,qu,"ignoring duplicate CNAME (%s, as well as %s)",
+                   adns__diag_domain(ads,serv,qu, &qu->vb, dgram,dglen,rdstart),
+                   qu->answer->cname);
+      }

     } else if (rrtype == (qu->typei->type & adns__rrt_typemask)) {
       wantedrrs++;
     } else {
     } else if (rrtype == (qu->typei->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) */
   nsstart= cbyte;
 
   if (!wantedrrs) {
     /* Oops, NODATA or NXDOMAIN or perhaps a referral (which would be a problem) */

-    
-    if (rcode == rcode_nxdomain) {
-      adns__query_finish(ads,qu,adns_s_nxdomain);
-      return;
-    }

 
     /* RFC2308: NODATA has _either_ a SOA _or_ _no_ NS records in authority section */
 
     /* RFC2308: NODATA has _either_ a SOA _or_ _no_ NS records in authority section */

-    foundsoa= 0; foundns= 0;
+    foundsoa= 0; soattl= 0; foundns= 0;

     for (rri= 0; rri<nscount; rri++) {
       rrstart= cbyte;
     for (rri= 0; rri<nscount; rri++) {
       rrstart= cbyte;

-      st= adns__get_rr_temp(ads,qu,serv, dgram,dglen,&cbyte,
-                           &rrtype,&rrclass, &rdlength,&rdstart, 0,0,0,0);
-      if (st) { adns__query_fail(ads,qu,st); return; }
+      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) {
       if (rrtype==-1) goto x_truncated;
       if (rrclass != DNS_CLASS_IN) {

-       adns__diag(ads,serv,"ignoring authority RR with wrong class %d (expected IN=%d)",
+       adns__diag(ads,serv,qu,
+                  "ignoring authority RR with wrong class %d (expected IN=%d)",

                   rrclass,DNS_CLASS_IN);
        continue;
       }
                   rrclass,DNS_CLASS_IN);
        continue;
       }

-      if (rrtype == adns_r_soa_raw) { foundsoa= 1; break; }
+      if (rrtype == adns_r_soa_raw) { foundsoa= 1; soattl= ttl; break; }

       else if (rrtype == adns_r_ns_raw) { foundns= 1; }
     }
       else if (rrtype == adns_r_ns_raw) { foundns= 1; }
     }

+    
+    if (rcode == rcode_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) {
+       adns__search_next(ads,qu,now);
+      } else {
+       adns__query_fail(qu,adns_s_nxdomain);
+      }
+      return;
+    }

 
     if (foundsoa || !foundns) {
       /* Aha !  A NODATA response, good. */
 
     if (foundsoa || !foundns) {
       /* Aha !  A NODATA response, good. */

-      adns__query_finish(ads,qu,adns_s_nodata);
+      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
       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 then perhaps we should do our own CNAME lookup.
+     * 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 (qu->cnameoff != -1) { cname_recurse(ads,qu,0); return; }
+    if (cname_here) goto x_restartquery;

 
     /* Bloody hell, I thought we asked for recursion ? */
 
     /* Bloody hell, I thought we asked for recursion ? */

+    if (flg_rd) {
+      adns__diag(ads,serv,qu,"server thinks we didn't ask for recursive lookup");
+    }

     if (!flg_ra) {
     if (!flg_ra) {

-      adns__diag(ads,serv,"server is not willing to do recursive lookups for us");
-      adns__query_fail(ads,qu,adns_s_norecurse);
-      return;
+      adns__diag(ads,serv,qu,"server is not willing to do recursive lookups for us");
+      adns__query_fail(qu,adns_s_norecurse);
+    } else {
+      adns__diag(ads,serv,qu,"server claims to do recursion, but gave us a referral");
+      adns__query_fail(qu,adns_s_invalidresponse);

     }
     }

-    adns__diag(ads,serv,"server claims to do recursion, but gave us a referral");
-    adns__query_fail(ads,qu,adns_s_serverfaulty);

     return;
   }
 
   /* Now, we have some RRs which we wanted. */
 
     return;
   }
 
   /* Now, we have some RRs which we wanted. */
 

-  qu->rrsoff= adns__vbuf_malloc(&qu->ans,qu->typei->rrsz*wantedrrs);
-  if (qu->rrsoff == -1) adns__query_fail(ads,qu,adns_s_nolocalmem);
+  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;
   cbyte= anstart;

-  currentrrs= 0;
-  arstart= -1;
-  for (rri=0; rri<ancount; rri++) {
-    st= adns__get_rr_temp(ads,qu,serv, dgram,dglen,&cbyte,
-                         &rrtype,&rrclass, &rdlength,&rdstart, 0,0,0,0);
+  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 ||
     assert(!st); assert(rrtype != -1);
     if (rrclass != DNS_CLASS_IN ||

-       rrtype != (qu->typei->type & adns__rrt_typemask))
+       rrtype != (qu->typei->type & adns__rrt_typemask) ||
+       !ownermatched)

       continue;
       continue;

-    assert(currentrrs<wantedrrs);
-    st= qu->typei->get_fn(ads,qu,serv, dgram,dglen, &rdstart,rdstart+rdlength,
-                         nsstart,arcount,&arstart, qu->rrsoff,&currentrrs);
-    if (st) { adns__query_fail(ads,qu,st); return; }
-    if (currentrrs==-1) goto x_truncated;
+    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++;

   }
   }

+  assert(nrrs==wantedrrs);
+  qu->answer->nrrs= nrrs;

 
   /* This may have generated some child queries ... */
   if (qu->children.head) {
 
   /* This may have generated some child queries ... */
   if (qu->children.head) {


@@ -238,22 +313,34 @@ void adns__procdgram(adns_state ads, const byte *dgram, int dglen,
     LIST_LINK_TAIL(ads->childw,qu);
     return;
   }
     LIST_LINK_TAIL(ads->childw,qu);
     return;
   }

-
-  adns__query_finish(ads,qu,adns_s_ok);
+  adns__query_done(qu);

   return;
 
   return;
 

-x_truncated:
+ x_truncated:
+  

   if (!flg_tc) {
   if (!flg_tc) {

-    adns__diag(ads,serv,"server sent datagram which points outside itself");
-    adns__query_fail(ads,qu,adns_s_serverfaulty);
+    adns__diag(ads,serv,qu,"server sent datagram which points outside itself");
+    adns__query_fail(qu,adns_s_invalidresponse);

     return;
   }
     return;
   }

-  if (qu->cnameoff != -1) { cname_recurse(ads,qu,adns_qf_usevc); return; }
-  qu->cnameoff= -1;
-  qu->rrsoff= -1;
-  ans= (adns_answer*)qu->ans.buf;
-  ans->nrrs= 0;
-  qu->ans.used= sizeof(adns_answer);

   qu->flags |= adns_qf_usevc;
   qu->flags |= adns_qf_usevc;

-  adns__query_udp(ads,qu,now);
+  
+ 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->typei->type, qu->flags);
+    if (st) { adns__query_fail(qu,st); return; }
+    
+    newquery= realloc(qu->query_dgram,qu->vb.used);
+    if (!newquery) { adns__query_fail(qu,adns_s_nomemory); return; }
+    
+    qu->query_dgram= newquery;
+    qu->query_dglen= qu->vb.used;
+    memcpy(newquery,qu->vb.buf,qu->vb.used);
+  }
+  
+  if (qu->state == query_tcpsent) qu->state= query_tosend;
+  adns__reset_preserved(qu);
+  adns__query_send(qu,now);

 }
 }