[PATCH/RFC 03/13] Don't do the TCP socket lookup if we already have one attached
From: KOVACS Krisztian <hidden>
Date: 2007-03-05 15:45:22
Subsystem:
networking [general], networking [tcp], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Neal Cardwell, Linus Torvalds
TCP input code path looks up the TCP socket hash tables to find a socket matching the incoming packet. However, as iptable_tproxy does socket lookups early the skb may already have the appropriate reference attached, in that case we steal that reference instead of doing the lookup. Signed-off-by: KOVACS Krisztian <redacted> --- net/ipv4/tcp_ipv4.c | 13 ++++++++++--- 1 files changed, 10 insertions(+), 3 deletions(-)
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 0ba74bb..536db7b 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c@@ -1647,9 +1647,16 @@ int tcp_v4_rcv(struct sk_buff *skb) TCP_SKB_CB(skb)->flags = skb->nh.iph->tos; TCP_SKB_CB(skb)->sacked = 0; - sk = __inet_lookup(&tcp_hashinfo, skb->nh.iph->saddr, th->source, - skb->nh.iph->daddr, th->dest, - inet_iif(skb)); + if (unlikely(skb->sk)) { + /* steal reference */ + sk = skb->sk; + skb->destructor = NULL; + skb->sk = NULL; + } else { + sk = __inet_lookup(&tcp_hashinfo, skb->nh.iph->saddr, th->source, + skb->nh.iph->daddr, th->dest, + inet_iif(skb)); + } if (!sk) goto no_tcp_socket;