net: ipv4: fix list processing on L3 slave devices

If we have an L3 master device, l3mdev_ip_rcv() will steal the skb, but
 we were returning NET_RX_SUCCESS from ip_rcv_finish_core() which meant
 that ip_list_rcv_finish() would keep it on the list.  Instead let's
 move the l3mdev_ip_rcv() call into the caller, so that our response to
 a steal can be different in the single packet path (return
 NET_RX_SUCCESS) and the list path (forget this packet and continue).

Fixes: 5fa12739a53d ("net: ipv4: listify ip_rcv_finish")
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
index 14ba628b2761a6b9b11e092cd55d395dae617d0f..1a3b6f32b1c903caab7e83d3aa833fb01638de8d 100644 (file)
--- a/net/ipv4/ip_input.c
+++ b/net/ipv4/ip_input.c
@@ -316,13 +316,6 @@ static int ip_rcv_finish_core(struct net *net, struct sock *sk,
        struct rtable *rt;
        int err;
 
-       /* if ingress device is enslaved to an L3 master device pass the
-        * skb to its handler for processing
-        */
-       skb = l3mdev_ip_rcv(skb);
-       if (!skb)
-               return NET_RX_SUCCESS;
-
        if (net->ipv4.sysctl_ip_early_demux &&
            !skb_dst(skb) &&
            !skb->sk &&
@@ -408,8 +401,16 @@ drop_error:
 
 static int ip_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
-       int ret = ip_rcv_finish_core(net, sk, skb);
+       int ret;
+
+       /* if ingress device is enslaved to an L3 master device pass the
+        * skb to its handler for processing
+        */
+       skb = l3mdev_ip_rcv(skb);
+       if (!skb)
+               return NET_RX_SUCCESS;
 
+       ret = ip_rcv_finish_core(net, sk, skb);
        if (ret != NET_RX_DROP)
                ret = dst_input(skb);
        return ret;
@@ -545,6 +546,12 @@ static void ip_list_rcv_finish(struct net *net, struct sock *sk,
                struct dst_entry *dst;
 
                list_del(&skb->list);
+               /* if ingress device is enslaved to an L3 master device pass the
+                * skb to its handler for processing
+                */
+               skb = l3mdev_ip_rcv(skb);
+               if (!skb)
+                       continue;
                if (ip_rcv_finish_core(net, sk, skb) == NET_RX_DROP)
                        continue;