Use a simpler arrangement for the all_addr union to avoid

the compiler padding it with an extra 8 bytes.

Use the F_KEYTAG flag in a a cache record to discriminate between
an arbitrary RR stored entirely in the addr union and one
which has a point to block storage.

3 files changed, 84 insertions, 51 deletions

diff --git a/src/cache.c b/src/cache.c
index 06ed672..fd10240 100644
--- a/src/cache.c
+++ b/src/cache.c
@@ -275,8 +275,8 @@ static void cache_blockdata_free(struct crec *crecp)
 {
   if (!(crecp->flags & F_NEG))
     {
-      if (crecp->flags & F_RR && crecp->addr.rr.len == -1)
-	blockdata_free(crecp->addr.rr.u.block.rrdata);
+      if ((crecp->flags & F_RR) && (crecp->flags & F_KEYTAG))
+	blockdata_free(crecp->addr.rrblock.rrdata);
 #ifdef HAVE_DNSSEC
       else if (crecp->flags & F_DNSKEY)
 	blockdata_free(crecp->addr.key.keydata);
@@ -469,10 +469,20 @@ static struct crec *cache_scan_free(char *name, union all_addr *addr, unsigned s
 	{
 	  if ((crecp->flags & F_FORWARD) && hostname_isequal(cache_get_name(crecp), name))
 	    {
+	      int rrmatch = 0;
+	      if (crecp->flags & flags & F_RR)
+		{
+		  unsigned short rrc = (crecp->flags & F_KEYTAG) ? crecp->addr.rrblock.rrtype : crecp->addr.rrdata.rrtype;
+		  unsigned short rra = (flags & F_KEYTAG) ? addr->rrblock.rrtype : addr->rrdata.rrtype;
+
+		  if (rrc == rra)
+		    rrmatch = 1;
+		}
+
 	      /* Don't delete DNSSEC in favour of a CNAME, they can co-exist */
-	      if ((flags & crecp->flags & (F_IPV4 | F_IPV6 | F_RR | F_NXDOMAIN)) || 
+	      if ((flags & crecp->flags & (F_IPV4 | F_IPV6 | F_NXDOMAIN)) || 
 		  (((crecp->flags | flags) & F_CNAME) && !(crecp->flags & (F_DNSKEY | F_DS))) ||
-		  ((crecp->flags & flags & F_RR) && addr->rr.rrtype == crecp->addr.rr.rrtype))
+		  rrmatch)
 		{
 		  if (crecp->flags & (F_HOSTS | F_DHCP | F_CONFIG))
 		    return crecp;
@@ -795,8 +805,8 @@ void cache_end_insert(void)
 	      if (flags & F_RR)
 		{
 		  /* A negative RR entry is possible and has no data, obviously. */
-		  if (!(flags & F_NEG) && new_chain->addr.rr.len == -1)
-		    blockdata_write(new_chain->addr.rr.u.block.rrdata, new_chain->addr.rr.u.block.datalen, daemon->pipe_to_parent);
+		  if (!(flags & F_NEG) && (flags & F_KEYTAG))
+		    blockdata_write(new_chain->addr.rrblock.rrdata, new_chain->addr.rrblock.datalen, daemon->pipe_to_parent);
 		}
 #ifdef HAVE_DNSSEC
 	      if (flags & F_DNSKEY)
@@ -869,8 +879,8 @@ int cache_recv_insert(time_t now, int fd)
 	  if (!read_write(fd, (unsigned char *)&addr, sizeof(addr), 1))
 	    return 0;
 	  
-	  if ((flags & F_RR) && !(flags & F_NEG) &&
-	      addr.rr.len == -1 && !(addr.rr.u.block.rrdata = blockdata_read(fd, addr.rr.u.block.datalen)))
+	  if ((flags & F_RR) && !(flags & F_NEG) && (flags & F_KEYTAG)
+	      && !(addr.rrblock.rrdata = blockdata_read(fd, addr.rrblock.datalen)))
 	    return 0;
 #ifdef HAVE_DNSSEC
 	   if (flags & F_DNSKEY)
@@ -1796,7 +1806,12 @@ static void dump_cache_entry(struct crec *cache, time_t now)
   if ((cache->flags & F_CNAME) && !is_outdated_cname_pointer(cache))
     a = sanitise(cache_get_cname_target(cache));
   else if (cache->flags & F_RR)
-    sprintf(a, "%s", querystr(NULL, cache->addr.rr.rrtype));
+    {
+      if (cache->flags & F_KEYTAG)
+	sprintf(a, "%s", querystr(NULL, cache->addr.rrblock.rrtype));
+      else
+	sprintf(a, "%s", querystr(NULL, cache->addr.rrdata.rrtype));
+    }
 #ifdef HAVE_DNSSEC
   else if (cache->flags & F_DS)
     {
@@ -2052,7 +2067,14 @@ void log_query(unsigned int flags, char *name, union all_addr *addr, char *arg,
     {
       dest = daemon->addrbuff;
 
-      if (flags & F_KEYTAG)
+       if (flags & F_RR)
+	 {
+	   if (flags & F_KEYTAG)
+	     dest = querystr(NULL, addr->rrblock.rrtype);
+	   else
+	     dest = querystr(NULL, addr->rrdata.rrtype);
+	 }
+       else if (flags & F_KEYTAG)
 	sprintf(daemon->addrbuff, arg, addr->log.keytag, addr->log.algo, addr->log.digest);
       else if (flags & F_RCODE)
 	{
@@ -2083,8 +2105,6 @@ void log_query(unsigned int flags, char *name, union all_addr *addr, char *arg,
 	      sprintf(portstring, "#%u", type);
 	    }
 	}
-      else if (flags & F_RR)
-	dest = querystr(NULL, addr->rr.rrtype);
       else
 	dest = arg;
     }
diff --git a/src/dnsmasq.h b/src/dnsmasq.h
index b6712f0..b7196f0 100644
--- a/src/dnsmasq.h
+++ b/src/dnsmasq.h
@@ -329,21 +329,23 @@ union all_addr {
     unsigned short keytag, algo, digest, rcode;
     int ede;
   } log;
-  /* for arbitrary RR record. */
+  /* for arbitrary RR record stored in block */
   struct {
-#define RR_IMDATALEN 13 /* 16 - sizeof(short) - sizeof (char) */
     unsigned short rrtype;
-    char len; /* -1 for blockdata */
-    union {
-      char data[RR_IMDATALEN];
-      struct {
-	unsigned short datalen;
-	struct blockdata *rrdata;
-      } block;
-    } u;
-  } rr;
+    unsigned short datalen; 
+    struct blockdata *rrdata;
+  } rrblock;
+  /* for arbitrary RR record small enough to go in addr.
+     NOTE: rrblock and rrdata are discriminated by the F_KEYTAG bit
+     in the cache flags. */
+  struct datablock {
+    unsigned short rrtype;
+    unsigned char datalen;
+    char data[];
+  } rrdata;
 };
 
+#define RR_IMDATALEN (sizeof(union all_addr) - offsetof(struct datablock, data))
 
 struct bogus_addr {
   int is6, prefix;
diff --git a/src/rfc1035.c b/src/rfc1035.c
index d4c6a26..ccf88df 100644
--- a/src/rfc1035.c
+++ b/src/rfc1035.c
@@ -806,20 +806,20 @@ int extract_addresses(struct dns_header *header, size_t qlen, char *name, time_t
 		  if (!CHECK_LEN(header, p1, qlen, ardlen))
 		    return 2; /* bad packet */
 		  
-		  addr.rr.rrtype = aqtype;
-
 		  /* If the data has no names and is small enough, store it in
 		     the crec address field rather than allocate a block. */
-		  if (*rrdesc == -1 && ardlen <= RR_IMDATALEN)
+		  if (*rrdesc == -1 && ardlen <= (int)RR_IMDATALEN)
 		    {
-		      addr.rr.len = (char)ardlen;
-		      if (ardlen != 0)
-			memcpy(addr.rr.u.data, p1, ardlen);
+		       addr.rrdata.rrtype = aqtype;
+		       addr.rrdata.datalen = (char)ardlen;
+		       if (ardlen != 0)
+			 memcpy(addr.rrdata.data, p1, ardlen);
 		    }
 		  else
 		    {
-		      addr.rr.len = -1;
-		      addr.rr.u.block.datalen = 0;
+		      addr.rrblock.rrtype = aqtype;
+		      addr.rrblock.datalen = 0;
+		      flags |= F_KEYTAG; /* discriminates between rrdata and rrblock */
 		      
 		      /* The RR data may include names, and those names may include
 			 compression, which will be rendered meaningless when
@@ -827,7 +827,7 @@ int extract_addresses(struct dns_header *header, size_t qlen, char *name, time_t
 			 Here we go through a description of the packet type to
 			 find the names, and extract them to a c-string and then
 			 re-encode them to standalone DNS format without compression. */
-		      if (!(addr.rr.u.block.rrdata = blockdata_alloc(NULL, 0)))
+		      if (!(addr.rrblock.rrdata = blockdata_alloc(NULL, 0)))
 			return 0;
 		      do
 			{
@@ -836,9 +836,9 @@ int extract_addresses(struct dns_header *header, size_t qlen, char *name, time_t
 			  if (desc == -1)
 			    {
 			      /* Copy the rest of the RR and end. */
-			      if (!blockdata_expand(addr.rr.u.block.rrdata, addr.rr.u.block.datalen, (char *)p1, endrr - p1))
+			      if (!blockdata_expand(addr.rrblock.rrdata, addr.rrblock.datalen, (char *)p1, endrr - p1))
 				return 0;
-			      addr.rr.u.block.datalen += endrr - p1;
+			      addr.rrblock.datalen += endrr - p1;
 			    }
 			  else if (desc == 0)
 			    {
@@ -849,18 +849,18 @@ int extract_addresses(struct dns_header *header, size_t qlen, char *name, time_t
 				return 2;
 			      
 			      len = to_wire(name);
-			      if (!blockdata_expand(addr.rr.u.block.rrdata, addr.rr.u.block.datalen, name, len))
+			      if (!blockdata_expand(addr.rrblock.rrdata, addr.rrblock.datalen, name, len))
 				return 0;
-			      addr.rr.u.block.datalen += len;
+			      addr.rrblock.datalen += len;
 			    }
 			  else
 			    {
 			      /* desc is length of a block of data to be used as-is */
 			      if (desc > endrr - p1)
 				desc = endrr - p1;
-			      if (!blockdata_expand(addr.rr.u.block.rrdata, addr.rr.u.block.datalen, (char *)p1, desc))
+			      if (!blockdata_expand(addr.rrblock.rrdata, addr.rrblock.datalen, (char *)p1, desc))
 				return 0;
-			      addr.rr.u.block.datalen += desc;
+			      addr.rrblock.datalen += desc;
 			      p1 += desc;
 			    }
 			} while (desc != -1);
@@ -968,7 +968,7 @@ int extract_addresses(struct dns_header *header, size_t qlen, char *name, time_t
 		ttl = cttl;
 	      
 	      if (flags & F_RR)
-		addr.rr.rrtype = qtype;
+		addr.rrdata.rrtype = qtype;
 
 	      newc = cache_insert(name, &addr, C_IN, now, ttl, F_FORWARD | F_NEG | flags | (secure ? F_DNSSECOK : 0));	
 	      if (newc && cpp)
@@ -2103,8 +2103,14 @@ size_t answer_request(struct dns_header *header, char *limit, size_t qlen,
 		 do
 		   {
 		     int flags = crecp->flags;
+		     unsigned short rrtype;
+		     
+		      if (flags & F_KEYTAG)
+			rrtype = crecp->addr.rrblock.rrtype;
+		      else
+			rrtype = crecp->addr.rrdata.rrtype;
 
-		     if ((flags & F_NXDOMAIN) || crecp->addr.rr.rrtype == qtype)
+		      if ((flags & F_NXDOMAIN) || rrtype == qtype)
 		       {
 			 if (crec_isstale(crecp, now))
 			   {
@@ -2127,23 +2133,28 @@ size_t answer_request(struct dns_header *header, char *limit, size_t qlen,
 			 
 			 if (!dryrun)
 			   {
-			     char *rrdata = crecp->addr.rr.u.data;
-			     unsigned short rrlen = crecp->addr.rr.len;
-			     
+			     char *rrdata = NULL;
+			     unsigned short rrlen = 0;
+
 			     if (!(flags & F_NEG))
 			       {
-				 if (crecp->addr.rr.len == -1)
+				 if (flags & F_KEYTAG)
+				   {
+				     rrlen = crecp->addr.rrblock.datalen;
+				     rrdata = blockdata_retrieve(crecp->addr.rrblock.rrdata, crecp->addr.rrblock.datalen, NULL);
+				   }
+				 else
 				   {
-				     rrlen = crecp->addr.rr.u.block.datalen;
-				     rrdata = blockdata_retrieve(crecp->addr.rr.u.block.rrdata, crecp->addr.rr.u.block.datalen, NULL);
+				     rrlen = crecp->addr.rrdata.datalen;
+				     rrdata = crecp->addr.rrdata.data;
 				   }
-				 
-				 if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, 
-							 crec_ttl(crecp, now), NULL, qtype, C_IN, "t",
-							 rrlen, rrdata))
-				   anscount++;
 			       }
 			     
+			     if (!(flags & F_NEG) && add_resource_record(header, limit, &trunc, nameoffset, &ansp, 
+									 crec_ttl(crecp, now), NULL, qtype, C_IN, "t",
+									 rrlen, rrdata))
+			       anscount++;
+			     			     
 			     /* log after cache insertion as log_txt mangles rrdata */
 			     if (qtype == T_TXT && !(crecp->flags & F_NEG))
 			       log_txt(name, (unsigned char *)rrdata, rrlen, crecp->flags & F_DNSSECOK);