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>
This commit is contained in:
Eric Dumazet 2012-07-24 01:19:31 +00:00 committed by David S. Miller
parent c20cd5d753
commit 9cb429d692
2 changed files with 6 additions and 8 deletions

View File

@ -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();
}

View File

@ -1686,7 +1686,6 @@ void tcp_v4_early_demux(struct sk_buff *skb)
struct net *net = dev_net(skb->dev);
const struct iphdr *iph;
const struct tcphdr *th;
struct net_device *dev;
struct sock *sk;
if (skb->pkt_type != PACKET_HOST)
@ -1701,14 +1700,10 @@ void tcp_v4_early_demux(struct sk_buff *skb)
if (th->doff < sizeof(struct tcphdr) / 4)
return;
if (!pskb_may_pull(skb, ip_hdrlen(skb) + th->doff * 4))
return;
dev = skb->dev;
sk = __inet_lookup_established(net, &tcp_hashinfo,
iph->saddr, th->source,
iph->daddr, ntohs(th->dest),
dev->ifindex);
skb->skb_iif);
if (sk) {
skb->sk = sk;
skb->destructor = sock_edemux;
@ -1718,7 +1713,7 @@ void tcp_v4_early_demux(struct sk_buff *skb)
if (dst)
dst = dst_check(dst, 0);
if (dst &&
icsk->rx_dst_ifindex == dev->ifindex)
icsk->rx_dst_ifindex == skb->skb_iif)
skb_dst_set_noref(skb, dst);
}
}