tree e1d94c916f4f8da5ba86dd2f855efc9b546839ef
parent a6963a6b3d2d3921b60f45e0cf18be26495d5ad1
author Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> 1190785610 -0700
committer David S. Miller <davem@sunset.davemloft.net> 1192060358 -0700

[TCP]: Reordered ACK's (old) SACKs not included to discarded MIB

In case of ACK reordering, the SACK block might be valid in it's
time but is already obsoleted since we've received another kind
of confirmation about arrival of the segments through snd_una
advancement of an earlier packet.

I didn't bother to build distinguishing of valid and invalid
SACK blocks but simply made reordered SACK blocks that are too
old always not counted regardless of their "real" validity which
could be determined by using the ack field of the reordered
packet (won't be significant IMHO).

DSACKs can very well be considered useful even in this situation,
so won't do any of this for them.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>