[NETFILTER]: nf_nat: fix random mode not to overwrite port rover
authorPatrick McHardy <kaber@trash.net>
Mon, 14 Apr 2008 09:15:46 +0000 (11:15 +0200)
committerPatrick McHardy <kaber@trash.net>
Mon, 14 Apr 2008 09:15:46 +0000 (11:15 +0200)
The port rover should not get overwritten when using random mode,
otherwise other rules will also use more or less random ports.

Signed-off-by: Patrick McHardy <kaber@trash.net>
net/ipv4/netfilter/nf_nat_proto_common.c

index a124213fb9da9d5245c8260f7171a4e639b6d971..871ab0eb325dc0f3dd52c4f46f9c94d28ed6b08b 100644 (file)
@@ -42,6 +42,7 @@ int nf_nat_proto_unique_tuple(struct nf_conntrack_tuple *tuple,
 {
        unsigned int range_size, min, i;
        __be16 *portptr;
+       u_int16_t off;
 
        if (maniptype == IP_NAT_MANIP_SRC)
                portptr = &tuple->src.u.all;
@@ -72,13 +73,17 @@ int nf_nat_proto_unique_tuple(struct nf_conntrack_tuple *tuple,
                range_size = ntohs(range->max.all) - min + 1;
        }
 
+       off = *rover;
        if (range->flags & IP_NAT_RANGE_PROTO_RANDOM)
-               *rover = net_random();
+               off = net_random();
 
-       for (i = 0; i < range_size; i++, (*rover)++) {
-               *portptr = htons(min + *rover % range_size);
-               if (!nf_nat_used_tuple(tuple, ct))
-                       return 1;
+       for (i = 0; i < range_size; i++, off++) {
+               *portptr = htons(min + off % range_size);
+               if (nf_nat_used_tuple(tuple, ct))
+                       continue;
+               if (!(range->flags & IP_NAT_RANGE_PROTO_RANDOM))
+                       *rover = off;
+               return 1;
        }
        return 0;
 }