tcp: early_demux fixes

1) Remove a non needed pskb_may_pull() in tcp_v4_early_demux()
   and fix a potential bug if skb->head was reallocated
   (iph & th pointers were not reloaded)

TCP stack will pull/check headers anyway.

2) must reload iph in ip_rcv_finish() after early_demux()
 call since skb->head might have changed.

3) skb->dev->ifindex can be now replaced by skb->skb_iif

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 1 deletions

diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
index 4ebc6feee250..93134b0eab0c 100644
--- a/net/ipv4/ip_input.c
+++ b/net/ipv4/ip_input.c
@@ -326,8 +326,11 @@ static int ip_rcv_finish(struct sk_buff *skb)
 
                 rcu_read_lock();
                 ipprot = rcu_dereference(inet_protos[protocol]);
-                if (ipprot && ipprot->early_demux)
+                if (ipprot && ipprot->early_demux) {
                         ipprot->early_demux(skb);
+                        /* must reload iph, skb->head might have changed */
+                        iph = ip_hdr(skb);
+                }
                 rcu_read_unlock();
         }