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authorDavid S. Miller <davem@davemloft.net>2012-06-19 21:22:05 -0700
committerDavid S. Miller <davem@davemloft.net>2012-06-19 21:22:05 -0700
commit41063e9dd11956f2d285e12e4342e1d232ba0ea2 (patch)
treed4df2f51044b4724a4767f0498c3df2f606b5ad7 /net/ipv4/tcp_minisocks.c
parentf9242b6b28d61295f2bf7e8adfb1060b382e5381 (diff)
downloadblackbird-op-linux-41063e9dd11956f2d285e12e4342e1d232ba0ea2.tar.gz
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ipv4: Early TCP socket demux.
Input packet processing for local sockets involves two major demuxes. One for the route and one for the socket. But we can optimize this down to one demux for certain kinds of local sockets. Currently we only do this for established TCP sockets, but it could at least in theory be expanded to other kinds of connections. If a TCP socket is established then it's identity is fully specified. This means that whatever input route was used during the three-way handshake must work equally well for the rest of the connection since the keys will not change. Once we move to established state, we cache the receive packet's input route to use later. Like the existing cached route in sk->sk_dst_cache used for output packets, we have to check for route invalidations using dst->obsolete and dst->ops->check(). Early demux occurs outside of a socket locked section, so when a route invalidation occurs we defer the fixup of sk->sk_rx_dst until we are actually inside of established state packet processing and thus have the socket locked. Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_minisocks.c')
-rw-r--r--net/ipv4/tcp_minisocks.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index cb015317c9f7..72b7c63b1a39 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -445,6 +445,8 @@ struct sock *tcp_create_openreq_child(struct sock *sk, struct request_sock *req,
struct tcp_sock *oldtp = tcp_sk(sk);
struct tcp_cookie_values *oldcvp = oldtp->cookie_values;
+ newsk->sk_rx_dst = dst_clone(skb_dst(skb));
+
/* TCP Cookie Transactions require space for the cookie pair,
* as it differs for each connection. There is no need to
* copy any s_data_payload stored at the original socket.
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