Generalise CNAME handling.

Cope with cached and configured CNAMES for all record types we
support, including local-config but not cached types such as TXT.

Also, if we have a locally configured CNAME but no target for the
requested type, don't forward the query.

src/rfc1035.c

@@ -1363,6 +1363,35 @@ size_t answer_request(struct dns_header *header, char *limit, size_t qlen,
 
       ans = 0; /* have we answered this question */
 
+      while ((crecp = cache_find_by_name(NULL, name, now, F_CNAME)))
+	{
+	  char *cname_target = cache_get_cname_target(crecp);
+
+	  /* If the client asked for DNSSEC  don't use cached data. */
+	  if ((crecp->flags & (F_HOSTS | F_DHCP | F_CONFIG)) ||
+	      !do_bit ||
+	      (option_bool(OPT_DNSSEC_VALID) && !(crecp->flags & F_DNSSECOK)))
+
+	    {
+	      if (crecp->flags & F_CONFIG || qtype == T_CNAME)
+		ans = 1;
+
+	      if (!(crecp->flags & F_DNSSECOK))
+		sec_data = 0;
+
+	      if (!dryrun)
+		{
+		  log_query(crecp->flags, name, NULL, record_source(crecp->uid));
+		  if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, 
+					  crec_ttl(crecp, now), &nameoffset,
+					  T_CNAME, C_IN, "d", cname_target))
+		    anscount++;
+		}
+	  
+	      strcpy(name, cname_target);
+	    }
+	}
+	  
       if (qtype == T_TXT || qtype == T_ANY)
 	{
 	  struct txt_record *t;
@@ -1614,7 +1643,6 @@ size_t answer_request(struct dns_header *header, char *limit, size_t qlen,
 		continue;
 	      
 	      /* interface name stuff */
-	    intname_restart:
 	      for (intr = daemon->int_names; intr; intr = intr->next)
 		if (hostname_isequal(name, intr->name))
 		  break;
@@ -1672,8 +1700,7 @@ size_t answer_request(struct dns_header *header, char *limit, size_t qlen,
 		  continue;
 		}
 
-	    cname_restart:
+	      if ((crecp = cache_find_by_name(NULL, name, now, flag | (dryrun ? F_NO_RR : 0))))
-	      if ((crecp = cache_find_by_name(NULL, name, now, flag | F_CNAME | (dryrun ? F_NO_RR : 0))))
 		{
 		  int localise = 0;
 		  
@@ -1689,7 +1716,7 @@ size_t answer_request(struct dns_header *header, char *limit, size_t qlen,
 			    localise = 1;
 			    break;
 			  } 
-			} while ((crecp = cache_find_by_name(crecp, name, now, flag | F_CNAME)));
+			} while ((crecp = cache_find_by_name(crecp, name, now, flag)));
 		      crecp = save;
 		    }
 
@@ -1707,27 +1734,6 @@ size_t answer_request(struct dns_header *header, char *limit, size_t qlen,
 			if (!(crecp->flags & F_DNSSECOK))
 			  sec_data = 0;
 			
-			if (crecp->flags & F_CNAME)
-			  {
-			    char *cname_target = cache_get_cname_target(crecp);
-			    
-			    if (!dryrun)
-			      {
-				log_query(crecp->flags, name, NULL, record_source(crecp->uid));
-				if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, 
-							crec_ttl(crecp, now), &nameoffset,
-							T_CNAME, C_IN, "d", cname_target))
-				  anscount++;
-			      }
-			    
-			    strcpy(name, cname_target);
-			    /* check if target interface_name */
-			    if (crecp->addr.cname.uid == SRC_INTERFACE)
-			      goto intname_restart;
-			    else
-			      goto cname_restart;
-			  }
-			
 			if (crecp->flags & F_NEG)
 			  {
 			    ans = 1;
@@ -1761,7 +1767,7 @@ size_t answer_request(struct dns_header *header, char *limit, size_t qlen,
 				  anscount++;
 			      }
 			  }
-		      } while ((crecp = cache_find_by_name(crecp, name, now, flag | F_CNAME)));
+		      } while ((crecp = cache_find_by_name(crecp, name, now, flag)));
 		}
 	      else if (is_name_synthetic(flag, name, &addr))
 		{
@@ -1776,27 +1782,6 @@ size_t answer_request(struct dns_header *header, char *limit, size_t qlen,
 		}
 	    }
 
-	  if (qtype == T_CNAME || qtype == T_ANY)
-	    {
-	      if ((crecp = cache_find_by_name(NULL, name, now, F_CNAME | (dryrun ? F_NO_RR : 0))) &&
-		  (qtype == T_CNAME || (crecp->flags & F_CONFIG)) &&
-		  ((crecp->flags & F_CONFIG) || !do_bit || (option_bool(OPT_DNSSEC_VALID) && !(crecp->flags & F_DNSSECOK))))
-		{
-		  if (!(crecp->flags & F_DNSSECOK))
-		    sec_data = 0;
-		  
-		  ans = 1;
-		  if (!dryrun)
-		    {
-		      log_query(crecp->flags, name, NULL, record_source(crecp->uid));
-		      if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, 
-					      crec_ttl(crecp, now), &nameoffset,
-					      T_CNAME, C_IN, "d", cache_get_cname_target(crecp)))
-			anscount++;
-		    }
-		}
-	    }
-
 	  if (qtype == T_MX || qtype == T_ANY)
 	    {
 	      int found = 0;
@@ -1880,8 +1865,7 @@ size_t answer_request(struct dns_header *header, char *limit, size_t qlen,
 
 	      if (!found)
 		{
-		cname_srv_restart:
+		  if ((crecp = cache_find_by_name(NULL, name, now, F_SRV | (dryrun ? F_NO_RR : 0))) &&
-		  if ((crecp = cache_find_by_name(NULL, name, now, F_CNAME | F_SRV | (dryrun ? F_NO_RR : 0))) &&
 		      (!do_bit || (option_bool(OPT_DNSSEC_VALID) && !(crecp->flags & F_DNSSECOK))))
 		    {
 		      if (!(crecp->flags & F_DNSSECOK))
@@ -1891,23 +1875,7 @@ size_t answer_request(struct dns_header *header, char *limit, size_t qlen,
 		      found = ans = 1;
 		      
 		      do {
-			if (crecp->flags & F_CNAME)
+			if (crecp->flags & F_NEG)
-			  {
-			    char *cname_target = cache_get_cname_target(crecp);
-			    
-			    if (!dryrun)
-			      {
-				log_query(crecp->flags, name, NULL, record_source(crecp->uid));
-				if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, 
-							crec_ttl(crecp, now), &nameoffset,
-							T_CNAME, C_IN, "d", cname_target))
-				  anscount++;
-			      }
-			    
-			    strcpy(name, cname_target);
-			    goto cname_srv_restart;
-			  }
-			else if (crecp->flags & F_NEG)
 			  {
 			    if (crecp->flags & F_NXDOMAIN)
 			      nxdomain = 1;
@@ -1935,7 +1903,7 @@ size_t answer_request(struct dns_header *header, char *limit, size_t qlen,
 				  return 0; /* bad packet */
 			      }
 			  }
-		      } while ((crecp = cache_find_by_name(crecp, name, now, F_SRV | F_CNAME)));
+		      } while ((crecp = cache_find_by_name(crecp, name, now, F_SRV)));
 		    }
 		}