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Commit 9cb429d6 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

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: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c20cd5d7

net/ipv4/ip_input.c

+4 −1
Original line number Diff line number Diff line
@@ -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();

	}

net/ipv4/tcp_ipv4.c

+2 −7
Original line number Diff line number Diff line
@@ -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);

		}

	}