CNAMEs can now point to interface names.

CHANGELOG

@@ -140,6 +140,10 @@ version 2.67
 	    Add --quiet-dhcp, --quiet-dhcp6 and --quiet-ra. Thanks to
 	    Kevin Darbyshire-Bryant for the initial patch.
 
+	    Allow A/AAAA records created by --interface-name to be the
+	    target of --cname. Thanks to Hadmut Danisch for the
+	    suggestion. 
+
  
 version 2.66
             Add the ability to act as an authoritative DNS

man/dnsmasq.8

@@ -497,7 +497,7 @@ Return an NAPTR DNS record, as specified in RFC3403.
 Return a CNAME record which indicates that <cname> is really
 <target>. There are significant limitations on the target; it must be a
 DNS name which is known to dnsmasq from /etc/hosts (or additional
-hosts files), from DHCP or from another 
+hosts files), from DHCP, from --interface-name or from another 
 .B --cname.
 If the target does not satisfy this
 criteria, the whole cname is ignored. The cname must be unique, but it

src/cache.c

@@ -24,7 +24,7 @@ static struct crec *new_chain = NULL;
 static int cache_inserted = 0, cache_live_freed = 0, insert_error;
 static union bigname *big_free = NULL;
 static int bignames_left, hash_size;
-static int uid = 0;
+static int uid = 1;
 #ifdef HAVE_DNSSEC
 static struct keydata *keyblock_free = NULL;
 #endif
@@ -76,7 +76,7 @@ void cache_init(void)
 {
   struct crec *crecp;
   int i;
-
+ 
   bignames_left = daemon->cachesize/10;
   
   if (daemon->cachesize > 0)
@@ -177,7 +177,10 @@ static void cache_free(struct crec *crecp)
   crecp->flags &= ~F_FORWARD;
   crecp->flags &= ~F_REVERSE;
   crecp->uid = uid++; /* invalidate CNAMES pointing to this. */
-  
+
+  if (uid == -1)
+    uid++;
+
   if (cache_tail)
     cache_tail->next = crecp;
   else
@@ -235,6 +238,16 @@ char *cache_get_name(struct crec *crecp)
   return crecp->name.sname;
 }
 
+char *cache_get_cname_target(struct crec *crecp)
+{
+  if (crecp->addr.cname.uid != -1)
+    return cache_get_name(crecp->addr.cname.target.cache);
+
+  return crecp->addr.cname.target.int_name->name;
+}
+
+
+
 struct crec *cache_enumerate(int init)
 {
   static int bucket;
@@ -260,14 +273,14 @@ struct crec *cache_enumerate(int init)
 
 static int is_outdated_cname_pointer(struct crec *crecp)
 {
-  if (!(crecp->flags & F_CNAME))
+  if (!(crecp->flags & F_CNAME) || crecp->addr.cname.uid == -1)
     return 0;
   
   /* NB. record may be reused as DS or DNSKEY, where uid is 
      overloaded for something completely different */
-  if (crecp->addr.cname.cache && 
-      (crecp->addr.cname.cache->flags & (F_IPV4 | F_IPV6 | F_CNAME)) &&
-      crecp->addr.cname.uid == crecp->addr.cname.cache->uid)
+  if (crecp->addr.cname.target.cache && 
+      (crecp->addr.cname.target.cache->flags & (F_IPV4 | F_IPV6 | F_CNAME)) &&
+      crecp->addr.cname.uid == crecp->addr.cname.target.cache->uid)
     return 0;
   
   return 1;
@@ -680,9 +693,9 @@ static void add_hosts_cname(struct crec *target)
     if (hostname_isequal(cache_get_name(target), a->target) &&
 	(crec = whine_malloc(sizeof(struct crec))))
       {
-	crec->flags = F_FORWARD | F_IMMORTAL | F_NAMEP | F_HOSTS | F_CNAME;
+	crec->flags = F_FORWARD | F_IMMORTAL | F_NAMEP | F_CONFIG | F_CNAME;
 	crec->name.namep = a->alias;
-	crec->addr.cname.cache = target;
+	crec->addr.cname.target.cache = target;
 	crec->addr.cname.uid = target->uid;
 	cache_hash(crec);
 	add_hosts_cname(crec); /* handle chains */
@@ -901,6 +914,8 @@ void cache_reload(void)
   struct hostsfile *ah;
   struct host_record *hr;
   struct name_list *nl;
+  struct cname *a;
+  struct interface_name *intr;
 
   cache_inserted = cache_live_freed = 0;
   
@@ -927,6 +942,20 @@ void cache_reload(void)
 	  up = &cache->hash_next;
       }
   
+  /* Add CNAMEs to interface_names to the cache */
+  for (a = daemon->cnames; a; a = a->next)
+    for (intr = daemon->int_names; intr; intr = intr->next)
+      if (hostname_isequal(a->target, intr->name))
+	{
+	  struct crec *aliasc = safe_malloc(sizeof(struct crec));
+	  aliasc->flags = F_FORWARD | F_NAMEP | F_CNAME | F_IMMORTAL | F_CONFIG;
+	  aliasc->name.namep = a->alias;
+	  aliasc->addr.cname.target.int_name = intr;
+	  aliasc->addr.cname.uid = -1;
+	  cache_hash(aliasc);
+	  add_hosts_cname(aliasc); /* handle chains */
+	}
+  
   /* borrow the packet buffer for a temporary by-address hash */
   memset(daemon->packet, 0, daemon->packet_buff_sz);
   revhashsz = daemon->packet_buff_sz / sizeof(struct crec *);
@@ -1019,13 +1048,13 @@ static void add_dhcp_cname(struct crec *target, time_t ttd)
 	
 	if (aliasc)
 	  {
-	    aliasc->flags = F_FORWARD | F_NAMEP | F_DHCP | F_CNAME;
+	    aliasc->flags = F_FORWARD | F_NAMEP | F_DHCP | F_CNAME | F_CONFIG;
 	    if (ttd == 0)
 	      aliasc->flags |= F_IMMORTAL;
 	    else
 	      aliasc->ttd = ttd;
 	    aliasc->name.namep = a->alias;
-	    aliasc->addr.cname.cache = target;
+	    aliasc->addr.cname.target.cache = target;
 	    aliasc->addr.cname.uid = target->uid;
 	    cache_hash(aliasc);
 	    add_dhcp_cname(aliasc, ttd);
@@ -1173,7 +1202,7 @@ void dump_cache(time_t now)
 	      {
 		a = "";
 		if (!is_outdated_cname_pointer(cache))
-		  a = cache_get_name(cache->addr.cname.cache);
+		  a = cache_get_cname_target(cache);
 	      }
 #ifdef HAVE_DNSSEC
 	    else if (cache->flags & F_DNSKEY)

src/dnsmasq.h

@@ -337,8 +337,11 @@ struct crec {
   union {
     struct all_addr addr;
     struct {
-      struct crec *cache;
-      int uid;
+      union {
+	struct crec *cache;
+	struct interface_name *int_name;
+      } target;
+      int uid; /* -1 if union is interface-name */
     } cname;
     struct {
       struct keydata *keydata;
@@ -941,6 +944,7 @@ struct in_addr a_record_from_hosts(char *name, time_t now);
 void cache_unhash_dhcp(void);
 void dump_cache(time_t now);
 char *cache_get_name(struct crec *crecp);
+char *cache_get_cname_target(struct crec *crecp);
 struct crec *cache_enumerate(int init);
 #ifdef HAVE_DNSSEC
 struct keydata *keydata_alloc(char *data, size_t len);

src/rfc1035.c

@@ -1042,10 +1042,10 @@ int extract_addresses(struct dns_header *header, size_t qlen, char *name, time_t
 			  newc = cache_insert(name, NULL, now, attl, F_CNAME | F_FORWARD);
 			  if (newc)
 			    {
-			      newc->addr.cname.cache = NULL;
+			      newc->addr.cname.target.cache = NULL;
 			      if (cpp)
 				{
-				  cpp->addr.cname.cache = newc;
+				  cpp->addr.cname.target.cache = newc;
 				  cpp->addr.cname.uid = newc->uid;
 				}
 			    }
@@ -1085,7 +1085,7 @@ int extract_addresses(struct dns_header *header, size_t qlen, char *name, time_t
 			  newc = cache_insert(name, &addr, now, attl, flags | F_FORWARD);
 			  if (newc && cpp)
 			    {
-			      cpp->addr.cname.cache = newc;
+			      cpp->addr.cname.target.cache = newc;
 			      cpp->addr.cname.uid = newc->uid;
 			    }
 			  cpp = NULL;
@@ -1112,7 +1112,7 @@ int extract_addresses(struct dns_header *header, size_t qlen, char *name, time_t
 		  newc = cache_insert(name, NULL, now, ttl ? ttl : cttl, F_FORWARD | F_NEG | flags);	
 		  if (newc && cpp)
 		    {
-		      cpp->addr.cname.cache = newc;
+		      cpp->addr.cname.target.cache = newc;
 		      cpp->addr.cname.uid = newc->uid;
 		    }
 		}
@@ -1720,7 +1720,7 @@ size_t answer_request(struct dns_header *header, char *limit, size_t qlen,
 		}
 
 	      /* interface name stuff */
-	      
+	    intname_restart:
 	      for (intr = daemon->int_names; intr; intr = intr->next)
 		if (hostname_isequal(name, intr->name))
 		  break;
@@ -1784,17 +1784,23 @@ size_t answer_request(struct dns_header *header, char *limit, size_t qlen,
 		      
 		      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", cache_get_name(crecp->addr.cname.cache)))
+						      T_CNAME, C_IN, "d", cname_target))
 				anscount++;
 			    }
 			  
-			  strcpy(name, cache_get_name(crecp->addr.cname.cache));
-			  goto cname_restart;
+			  strcpy(name, cname_target);
+			  /* check if target interface_name */
+			  if (crecp->addr.cname.uid == -1)
+			    goto intname_restart;
+			  else
+			    goto cname_restart;
 			}
 		      
 		      if (crecp->flags & F_NEG)
@@ -1856,7 +1862,7 @@ size_t answer_request(struct dns_header *header, char *limit, size_t qlen,
 		      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_name(crecp->addr.cname.cache)))
+					      T_CNAME, C_IN, "d", cache_get_cname_target(crecp)))
 			anscount++;
 		    }
 		}