Commit:     2948d2ebbb98747b912ac6d0c864b4d02be8a6f5
Parent:     0ff4d77bd9fe86ca1bc7f44839d79f8a349a62f0
Author:     Patrick McHardy <[EMAIL PROTECTED]>
AuthorDate: Fri Jan 11 18:02:18 2008 -0800
Committer:  David S. Miller <[EMAIL PROTECTED]>
CommitDate: Fri Jan 11 18:02:18 2008 -0800

    [NETFILTER]: bridge: fix double POST_ROUTING invocation
    The bridge code incorrectly causes two POST_ROUTING hook invocations
    for DNATed packets that end up on the same bridge device. This
    happens because packets with a changed destination address are passed
    to dst_output() to make them go through the neighbour output function
    again to build a new destination MAC address, before they will continue
    through the IP hooks simulated by bridge netfilter.
    The resulting hook order is:
     PREROUTING (bridge netfilter)
     POSTROUTING        (dst_output -> ip_output)
     FORWARD    (bridge netfilter)
     POSTROUTING        (bridge netfilter)
    The deferred hooks used to abort the first POST_ROUTING invocation,
    but since the only thing bridge netfilter actually really wants is
    a new MAC address, we can avoid going through the IP stack completely
    by simply calling the neighbour output function directly.
    Tested, reported and lots of data provided by: Damien Thebault <[EMAIL 
    Signed-off-by: Patrick McHardy <[EMAIL PROTECTED]>
    Signed-off-by: David S. Miller <[EMAIL PROTECTED]>
 net/bridge/br_netfilter.c |   18 ++++++++++++------
 1 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c
index c1757c7..5d8b939 100644
--- a/net/bridge/br_netfilter.c
+++ b/net/bridge/br_netfilter.c
@@ -247,8 +247,9 @@ static void __br_dnat_complain(void)
  * Let us first consider the case that ip_route_input() succeeds:
  * If skb->dst->dev equals the logical bridge device the packet
- * came in on, we can consider this bridging. We then call
- * skb->dst->output() which will make the packet enter br_nf_local_out()
+ * came in on, we can consider this bridging. The packet is passed
+ * through the neighbour output function to build a new destination
+ * MAC address, which will make the packet enter br_nf_local_out()
  * not much later. In that function it is assured that the iptables
  * FORWARD chain is traversed for the packet.
@@ -285,12 +286,17 @@ static int br_nf_pre_routing_finish_bridge(struct sk_buff 
        skb->nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
        skb->dev = bridge_parent(skb->dev);
-       if (!skb->dev)
-               kfree_skb(skb);
-       else {
+       if (skb->dev) {
+               struct dst_entry *dst = skb->dst;
-               skb->dst->output(skb);
+               if (dst->hh)
+                       return neigh_hh_output(dst->hh, skb);
+               else if (dst->neighbour)
+                       return dst->neighbour->output(skb);
+       kfree_skb(skb);
        return 0;
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