TCP SACK improvements (RFC6675 rescue retransmission and lost retransmission detection)

[Scheffenegger, Richard]

Hi,

I hope this is the correct forum to ask for help improving a rather crude patch to introduce RFC6675 Rescue Retransmissions and efficient Lost Retransmission Detection. Note that this is not a full implementation of the RFC6675.

The patch that I have is against 8.0, but I believe the SACK scoreboard has not really changed and thus should be applicable still.

One outstanding issue of that patch is the missing interaction with the congestion control part, when retransmitting a lost retransmission (that should reduce cwnd once  per cycle).

Also, the implementation is not very efficient, as more traversals of the scoreboard are done checking the elegibility of prior holes to be in need of being retransmitted once more...


Best regards,
  Richard Scheffenegger

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