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Yuchung Cheng authored
Currently a Linux IPv6 TCP sender will change the flow label upon timeouts to potentially steer away from a data path that has gone bad. However this does not help if the problem is on the ACK path and the data path is healthy. In this case the receiver is likely to receive repeated spurious retransmission because the sender couldn't get the ACKs in time and has recurring timeouts. This patch adds another feature to mitigate this problem. It leverages the DSACK states in the receiver to change the flow label of the ACKs to speculatively re-route the ACK packets. In order to allow triggering on the second consecutive spurious RTO, the receiver changes the flow label upon sending a second consecutive DSACK for a sequence number below RCV.NXT. Signed-off-by:
Yuchung Cheng <ycheng@google.com> Signed-off-by:
Neal Cardwell <ncardwell@google.com> Signed-off-by:
Eric Dumazet <edumazet@google.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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