All except rrtype-specific stuff complete but largely untest. That is

[adns] / src / reply.c

diff --git a/src/reply.c b/src/reply.c
index 6aacd2b820c160c9706e5919c0a00a80b98aa3a6..39337e881de251d822ba20ad35bd3c26e37186c3 100644 (file)
--- a/src/reply.c
+++ b/src/reply.c
@@ -2,29 +2,39 @@
 
 #include "internal.h"
 
 
 #include "internal.h"
 

-typedef enum {
-  rcode_noerror,
-  rcode_formaterror,
-  rcode_serverfail,
-  rcode_nxdomain,
-  rcode_notimp,
-  rcode_refused
-} dns_rcode;
-
-void adns__procdgram(adns_state ads, const byte *dgram, int len, int serv) {
-  unsigned char *rpp;
+static void cname_recurse(adns_state ads, adns_query qu, adns_queryflags xflags) {
+  abort(); /* FIXME */
+}
+    
+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 anstart, nsstart, arstart;
+  int currentrrs;
+  adns_query qu, nqu;
+  dns_rcode rcode;
+  adns_status st;
+  adns_answer *ans;
+
+  cbyte= 0;

   
   

-  if (len<12) {
-    adns__diag(ads,serv,"received datagram too short for message header (%d)",len);
+  if (dglen<DNS_HDRSIZE) {
+    adns__diag(ads,serv,"received datagram too short for message header (%d)",dglen);

     return;
   }
     return;
   }

-  id= GFREPLYW;
-  f1= GFREPLYB;
-  f2= GFREPLYB;
-  qdcount= GFREPLYW;
-  ancount= GFREPLYW;
-  nscount= GFREPLYW;
-  arcount= GFREPLYW;
+  GET_W(cbyte,id);
+  GET_B(cbyte,f1);
+  GET_B(cbyte,f2);
+  GET_W(cbyte,qdcount);
+  GET_W(cbyte,ancount);
+  GET_W(cbyte,nscount);
+  GET_W(cbyte,arcount);
+  assert(cbyte == DNS_HDRSIZE);
+
+  flg_tc= f1&0x20;
+  flg_ra= f2&0x80;

 
   if (f1&0x80) {
     adns__diag(ads,serv,"server sent us a query, not a response");
 
   if (f1&0x80) {
     adns__diag(ads,serv,"server sent us a query, not a response");


@@ -43,42 +53,207 @@ void adns__procdgram(adns_state ads, const byte *dgram, int len, int serv) {
               qdcount);
     return;
   }
               qdcount);
     return;
   }

-  for (qu= ads->timew; qu= nqu; qu++) {
+  for (qu= ads->timew.head; qu; qu= nqu) {

     nqu= qu->next;
     if (qu->id != id) continue;
     nqu= qu->next;
     if (qu->id != id) continue;

-    if (len < qu->querylen) continue;
-    if (memcmp(qu->querymsg+12,rpp,qu->querylen-12)) continue;
+    if (dglen < qu->querylen) continue;
+    if (memcmp(qu->querymsg+DNS_HDRSIZE,dgram+DNS_HDRSIZE,qu->querylen-DNS_HDRSIZE))
+      continue;

     break;
   }
     break;
   }

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

   if (!qu) {
     adns__debug(ads,serv,"reply not found (id=%02x)",id);
     return;
   }
   if (!qu) {
     adns__debug(ads,serv,"reply not found (id=%02x)",id);
     return;
   }

-  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);
-    return;
-  }
+
+  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;
   }
   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;
   }

-  switch (f1&0x0f) {
-  case 0: /* NOERROR */
+
+  rcode= (f1&0x0f);
+  switch (rcode) {
+  case rcode_noerror:
+  case rcode_nxdomain:

     break;
     break;

-  case 1: /* Format error */
-    adns__diag(ads,serv,"server cannot understand our query (Format Error)");
+  case rcode_formaterror:
+    adns__warn(ads,serv,"server cannot understand our query (Format Error)");

     adns__query_fail(ads,qu,adns_s_serverfaulty);
     return;
     adns__query_fail(ads,qu,adns_s_serverfaulty);
     return;

-  case 2: /* Server failure */
-    adns__query_fail(ads,qu,adns_s_serverfailure);
+  case rcode_servfail:
+    adns__query_fail(ads,qu,adns_s_servfail);

     return;
     return;

-  case 3: /* Name Error */
-  
-  qr= f1&0x80;
-  
-             
-  adns__diag(ads,serv,"received datagram size %d",len);
+  case rcode_notimp:
+    adns__warn(ads,serv,"server claims not to implement our query");
+    adns__query_fail(ads,qu,adns_s_notimplemented);
+    return;
+  case rcode_refused:
+    adns__warn(ads,serv,"server refused our query");
+    adns__query_fail(ads,qu,adns_s_refused);
+    return;
+  default:
+    adns__warn(ads,serv,"server gave unknown response code %d",rcode);
+    adns__query_fail(ads,qu,adns_s_reasonunknown);
+    return;
+  }
+
+  /* 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;
+  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);
+    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)",
+                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");
+      }
+      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.
+       */
+    } else if (rrtype == (qu->typei->type & adns__rrt_typemask)) {
+      wantedrrs++;
+    } else {
+      adns__debug(ads,serv,"ignoring answer RR with irrelevant type %d",rrtype);
+    }
+  }
+
+  /* If we got here then the answer section is intact. */
+  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 */
+    foundsoa= 0; foundns= 0;
+    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; }
+      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)",
+                  rrclass,DNS_CLASS_IN);
+       continue;
+      }
+      if (rrtype == adns_r_soa_raw) { foundsoa= 1; break; }
+      else if (rrtype == adns_r_ns_raw) { foundns= 1; }
+    }
+
+    if (foundsoa || !foundns) {
+      /* Aha !  A NODATA response, good. */
+      adns__query_finish(ads,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 then perhaps we should do our own CNAME lookup.
+     */
+    if (qu->cnameoff != -1) { cname_recurse(ads,qu,0); return; }
+
+    /* Bloody hell, I thought we asked for recursion ? */
+    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,"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. */
+
+  qu->rrsoff= adns__vbuf_malloc(&qu->ans,qu->typei->rrsz*wantedrrs);
+  if (qu->rrsoff == -1) adns__query_fail(ads,qu,adns_s_nolocalmem);
+
+  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);
+    assert(!st); assert(rrtype != -1);
+    if (rrclass != DNS_CLASS_IN ||
+       rrtype != (qu->typei->type & adns__rrt_typemask))
+      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;
+  }
+
+  /* This may have generated some child queries ... */
+  if (qu->children.head) {
+    qu->state= query_child;
+    LIST_LINK_TAIL(ads->childw,qu);
+    return;
+  }
+
+  adns__query_finish(ads,qu,adns_s_ok);
+  return;
+
+x_truncated:
+  if (!flg_tc) {
+    adns__diag(ads,serv,"server sent datagram which points outside itself");
+    adns__query_fail(ads,qu,adns_s_serverfaulty);
+    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;
+  adns__query_udp(ads,qu,now);

 }
 }