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| author | Wei Wang <weiwan@google.com> | 2021-07-21 10:27:38 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-07-28 14:35:41 +0200 |
| commit | 164294d09c47b9a6c6160b08c43d74ae93c82758 (patch) | |
| tree | 83c439cd8a8a767f46f410509a255e6a8c3e42fe | |
| parent | 8eb225873246312660ccd68296959a7b213d0cdd (diff) | |
| download | kernel_replicant_linux-164294d09c47b9a6c6160b08c43d74ae93c82758.tar.gz kernel_replicant_linux-164294d09c47b9a6c6160b08c43d74ae93c82758.tar.bz2 kernel_replicant_linux-164294d09c47b9a6c6160b08c43d74ae93c82758.zip | |
tcp: disable TFO blackhole logic by default
[ Upstream commit 213ad73d06073b197a02476db3a4998e219ddb06 ]
Multiple complaints have been raised from the TFO users on the internet
stating that the TFO blackhole logic is too aggressive and gets falsely
triggered too often.
(e.g. https://blog.apnic.net/2021/07/05/tcp-fast-open-not-so-fast/)
Considering that most middleboxes no longer drop TFO packets, we decide
to disable the blackhole logic by setting
/proc/sys/net/ipv4/tcp_fastopen_blackhole_timeout_set to 0 by default.
Fixes: cf1ef3f0719b4 ("net/tcp_fastopen: Disable active side TFO in certain scenarios")
Signed-off-by: Wei Wang <weiwan@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | Documentation/networking/ip-sysctl.rst | 2 | ||||
| -rw-r--r-- | net/ipv4/tcp_fastopen.c | 9 | ||||
| -rw-r--r-- | net/ipv4/tcp_ipv4.c | 2 |
3 files changed, 10 insertions, 3 deletions
diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst index 4abcfff15e38..4822a058a81d 100644 --- a/Documentation/networking/ip-sysctl.rst +++ b/Documentation/networking/ip-sysctl.rst @@ -751,7 +751,7 @@ tcp_fastopen_blackhole_timeout_sec - INTEGER initial value when the blackhole issue goes away. 0 to disable the blackhole detection. - By default, it is set to 1hr. + By default, it is set to 0 (feature is disabled). tcp_fastopen_key - list of comma separated 32-digit hexadecimal INTEGERs The list consists of a primary key and an optional backup key. The diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c index 08548ff23d83..d49709ba8e16 100644 --- a/net/ipv4/tcp_fastopen.c +++ b/net/ipv4/tcp_fastopen.c @@ -507,6 +507,9 @@ void tcp_fastopen_active_disable(struct sock *sk) { struct net *net = sock_net(sk); + if (!sock_net(sk)->ipv4.sysctl_tcp_fastopen_blackhole_timeout) + return; + /* Paired with READ_ONCE() in tcp_fastopen_active_should_disable() */ WRITE_ONCE(net->ipv4.tfo_active_disable_stamp, jiffies); @@ -526,10 +529,14 @@ void tcp_fastopen_active_disable(struct sock *sk) bool tcp_fastopen_active_should_disable(struct sock *sk) { unsigned int tfo_bh_timeout = sock_net(sk)->ipv4.sysctl_tcp_fastopen_blackhole_timeout; - int tfo_da_times = atomic_read(&sock_net(sk)->ipv4.tfo_active_disable_times); unsigned long timeout; + int tfo_da_times; int multiplier; + if (!tfo_bh_timeout) + return false; + + tfo_da_times = atomic_read(&sock_net(sk)->ipv4.tfo_active_disable_times); if (!tfo_da_times) return false; diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 5212db9ea157..04e259a04443 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -2913,7 +2913,7 @@ static int __net_init tcp_sk_init(struct net *net) net->ipv4.sysctl_tcp_comp_sack_nr = 44; net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE; spin_lock_init(&net->ipv4.tcp_fastopen_ctx_lock); - net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 60 * 60; + net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 0; atomic_set(&net->ipv4.tfo_active_disable_times, 0); /* Reno is always built in */ |