[NETFILTER]: Fix HW checksum handling in ECN target

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 4 deletions

diff --git a/net/ipv4/netfilter/ipt_ECN.c b/net/ipv4/netfilter/ipt_ECN.c
index d3250a3a5db..94a0ce1c1c9 100644
--- a/net/ipv4/netfilter/ipt_ECN.c
+++ b/net/ipv4/netfilter/ipt_ECN.c
@@ -71,6 +71,10 @@ set_ect_tcp(struct sk_buff **pskb, const struct ipt_ECN_info *einfo, int inward)
                 return 0;
         tcph = (void *)(*pskb)->nh.iph + (*pskb)->nh.iph->ihl*4;
 
+        if ((*pskb)->ip_summed == CHECKSUM_HW &&
+            skb_checksum_help(*pskb, inward))
+                return 0;
+
         diffs[0] = ((u_int16_t *)tcph)[6];
         if (einfo->operation & IPT_ECN_OP_SET_ECE)
                 tcph->ece = einfo->proto.tcp.ece;
@@ -79,13 +83,10 @@ set_ect_tcp(struct sk_buff **pskb, const struct ipt_ECN_info *einfo, int inward)
         diffs[1] = ((u_int16_t *)tcph)[6];
         diffs[0] = diffs[0] ^ 0xFFFF;
 
-        if ((*pskb)->ip_summed != CHECKSUM_HW)
+        if ((*pskb)->ip_summed != CHECKSUM_UNNECESSARY)
                 tcph->check = csum_fold(csum_partial((char *)diffs,
                                                      sizeof(diffs),
                                                      tcph->check^0xFFFF));
-        else
-                if (skb_checksum_help(*pskb, inward))
-                        return 0;
         (*pskb)->nfcache |= NFC_ALTERED;
         return 1;
 }