ipv6: Compare addresses only bits up to the prefix length (RFC6724).

Compare bits up to the source address's prefix length only to allows DNS load balancing to continue to be used as a tie breaker. Signed-off-by: YOSHIFUJI Hideaki <[email protected]> Signed-off-by: David S. Miller <[email protected]>
jadonk · Sep 13, 2012 · 91b4b04 · 91b4b04
1 parent 417962a
commit 91b4b04
Showing 1 changed file with 4 additions and 2 deletions.
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
@@ -1070,8 +1070,10 @@ static int ipv6_get_saddr_eval(struct net *net,
 		break;
 	case IPV6_SADDR_RULE_PREFIX:
 		/* Rule 8: Use longest matching prefix */
-		score->matchlen = ret = ipv6_addr_diff(&score->ifa->addr,
-						       dst->addr);
+		ret = ipv6_addr_diff(&score->ifa->addr, dst->addr);
+		if (ret > score->ifa->prefix_len)
+			ret = score->ifa->prefix_len;
+		score->matchlen = ret;
 		break;
 	default:
 		ret = 0;