tcp: avoid setting cwnd to invalid ssthresh after cwnd reduction states
authorYuchung Cheng <ycheng@google.com>
Tue, 1 Aug 2017 20:22:32 +0000 (13:22 -0700)
committerDavid S. Miller <davem@davemloft.net>
Wed, 2 Aug 2017 17:51:07 +0000 (10:51 -0700)
commited254971edea92c3ac5c67c6a05247a92aa6075e
tree06c4b0d9564476c2ba90bdfb19b171a5cdf17bb1
parent4d96f12a072c669d48dc3a2c6b539a9faeca138d
tcp: avoid setting cwnd to invalid ssthresh after cwnd reduction states

If the sender switches the congestion control during ECN-triggered
cwnd-reduction state (CA_CWR), upon exiting recovery cwnd is set to
the ssthresh value calculated by the previous congestion control. If
the previous congestion control is BBR that always keep ssthresh
to TCP_INIFINITE_SSTHRESH, cwnd ends up being infinite. The safe
step is to avoid assigning invalid ssthresh value when recovery ends.

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/ipv4/tcp_input.c