act_nat: fix the wrong checksum when addr isn't in old_addr/mask
authorChangli Gao <xiaosuo@gmail.com>
Sat, 29 May 2010 14:26:59 +0000 (14:26 +0000)
committerDavid S. Miller <davem@davemloft.net>
Wed, 2 Jun 2010 13:51:34 +0000 (06:51 -0700)
fix the wrong checksum when addr isn't in old_addr/mask

For TCP and UDP packets, when addr isn't in old_addr/mask we don't do SNAT or
DNAT, and we should not update layer 4 checksum.

Signed-off-by: Changli Gao <xiaosuo@gmail.com>
----
 net/sched/act_nat.c |    4 ++++
 1 file changed, 4 insertions(+)
Signed-off-by: David S. Miller <davem@davemloft.net>
net/sched/act_nat.c

index d885ba311564d9a766fce6eac37edbaf0ed82b71..570949417f388735e93bf887294326a8f24aa534 100644 (file)
@@ -159,6 +159,9 @@ static int tcf_nat(struct sk_buff *skb, struct tc_action *a,
                        iph->daddr = new_addr;
 
                csum_replace4(&iph->check, addr, new_addr);
+       } else if ((iph->frag_off & htons(IP_OFFSET)) ||
+                  iph->protocol != IPPROTO_ICMP) {
+               goto out;
        }
 
        ihl = iph->ihl * 4;
@@ -247,6 +250,7 @@ static int tcf_nat(struct sk_buff *skb, struct tc_action *a,
                break;
        }
 
+out:
        return action;
 
 drop: