When a packet arrives via bridging, clone it if it is shared.

Otherwise we will mangle the packet for anyone who came before us
(e.g. tcpdump via AF_PACKET).

diff --git a/datapath/datapath.c b/datapath/datapath.c
index d27a9bc..e9d51a8 100644 (file)
--- a/datapath/datapath.c
+++ b/datapath/datapath.c
@@ -455,6 +455,14 @@ static int dp_maint_func(void *data)
 static void
 do_port_input(struct net_bridge_port *p, struct sk_buff *skb) 
 {
+       /* Make our own copy of the packet.  Otherwise we will mangle the
+        * packet for anyone who came before us (e.g. tcpdump via AF_PACKET).
+        * (No one comes after us, since we tell handle_bridge() that we took
+        * the packet.) */
+       skb = skb_share_check(skb, GFP_ATOMIC);
+       if (!skb)
+               return;
+
 #ifdef SUPPORT_SNAT
        /* Check if this packet needs early SNAT processing. */
        if (snat_pre_route(skb)) {