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authorYuchung Cheng <ycheng@google.com>2017-12-12 13:10:40 -0800
committerDavid S. Miller <davem@davemloft.net>2017-12-13 15:51:12 -0500
commit7268586baa530312041e597b518b5c6a05110df1 (patch)
tree09075b8fb35fcc5ad90f744345d1582fe7d62f4c /net/ipv4/tcp_metrics.c
parentnet: ethernet: ti: cpdma: correct error handling for chan create (diff)
downloadlinux-dev-7268586baa530312041e597b518b5c6a05110df1.tar.xz
linux-dev-7268586baa530312041e597b518b5c6a05110df1.zip
tcp: pause Fast Open globally after third consecutive timeout
Prior to this patch, active Fast Open is paused on a specific destination IP address if the previous connections to the IP address have experienced recurring timeouts . But recent experiments by Microsoft (https://goo.gl/cykmn7) and Mozilla browsers indicate the isssue is often caused by broken middle-boxes sitting close to the client. Therefore it is much better user experience if Fast Open is disabled out-right globally to avoid experiencing further timeouts on connections toward other destinations. This patch changes the destination-IP disablement to global disablement if a connection experiencing recurring timeouts or aborts due to timeout. Repeated incidents would still exponentially increase the pause time, starting from an hour. This is extremely conservative but an unfortunate compromise to minimize bad experience due to broken middle-boxes. Reported-by: Dragana Damjanovic <ddamjanovic@mozilla.com> Reported-by: Patrick McManus <mcmanus@ducksong.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Reviewed-by: Wei Wang <weiwan@google.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_metrics.c')
-rw-r--r--net/ipv4/tcp_metrics.c5
1 files changed, 1 insertions, 4 deletions
diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c
index 7097f92d16e5..759e6bc8327b 100644
--- a/net/ipv4/tcp_metrics.c
+++ b/net/ipv4/tcp_metrics.c
@@ -546,8 +546,7 @@ bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst)
static DEFINE_SEQLOCK(fastopen_seqlock);
void tcp_fastopen_cache_get(struct sock *sk, u16 *mss,
- struct tcp_fastopen_cookie *cookie,
- int *syn_loss, unsigned long *last_syn_loss)
+ struct tcp_fastopen_cookie *cookie)
{
struct tcp_metrics_block *tm;
@@ -564,8 +563,6 @@ void tcp_fastopen_cache_get(struct sock *sk, u16 *mss,
*cookie = tfom->cookie;
if (cookie->len <= 0 && tfom->try_exp == 1)
cookie->exp = true;
- *syn_loss = tfom->syn_loss;
- *last_syn_loss = *syn_loss ? tfom->last_syn_loss : 0;
} while (read_seqretry(&fastopen_seqlock, seq));
}
rcu_read_unlock();