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authorEric Dumazet <edumazet@google.com>2012-05-04 05:14:02 +0000
committerDavid S. Miller <davem@davemloft.net>2012-05-04 12:05:27 -0400
commitbd14b1b2e29bd6812597f896dde06eaf7c6d2f24 (patch)
treebd641279d50993e32da8f8d72672bce4e54820bd /net/ipv4
parentf45ebf3a6be9da051f078b30e7309b6788932189 (diff)
downloadop-kernel-dev-bd14b1b2e29bd6812597f896dde06eaf7c6d2f24.zip
op-kernel-dev-bd14b1b2e29bd6812597f896dde06eaf7c6d2f24.tar.gz
tcp: be more strict before accepting ECN negociation
It appears some networks play bad games with the two bits reserved for ECN. This can trigger false congestion notifications and very slow transferts. Since RFC 3168 (6.1.1) forbids SYN packets to carry CT bits, we can disable TCP ECN negociation if it happens we receive mangled CT bits in the SYN packet. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Perry Lorier <perryl@google.com> Cc: Matt Mathis <mattmathis@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Wilmer van der Gaast <wilmer@google.com> Cc: Ankur Jain <jankur@google.com> Cc: Tom Herbert <therbert@google.com> Cc: Dave Täht <dave.taht@bufferbloat.net> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/tcp_ipv4.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index cf97e98..4ff5e1f 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1368,7 +1368,7 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
goto drop_and_free;
if (!want_cookie || tmp_opt.tstamp_ok)
- TCP_ECN_create_request(req, tcp_hdr(skb));
+ TCP_ECN_create_request(req, skb);
if (want_cookie) {
isn = cookie_v4_init_sequence(sk, skb, &req->mss);
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