Commit f5771113 authored Nov 15, 2007 by Ilpo Järvinen Committed by David S. Miller Jan 28, 2008

[TCP]: Extend reordering detection to cover CA_Loss partially



This implements more accurately what is stated in sacktag's
overall comment:

  "Both of these heuristics are not used in Loss state, when
   we cannot account for retransmits accurately."

When CA_Loss state is entered, the state changer ensures that
undo_marker is only set if no TCPCB_RETRANS skbs were found,
thus having non-zero undo_marker in CA_Loss basically tells
that the R-bits still accurately reflect the current state
of TCP.

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

parent b9d86585

net/ipv4/tcp_input.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -1511,7 +1511,8 @@ tcp_sacktag_write_queue(struct sock sk, struct sk_buff ack_skb, u32 prior_snd_

		tcp_verify_left_out(tp);

		if ((reord < tp->fackets_out) && icsk->icsk_ca_state != TCP_CA_Loss &&
		if ((reord < tp->fackets_out) &&
		((icsk->icsk_ca_state != TCP_CA_Loss) \|\| tp->undo_marker) &&
		(!tp->frto_highmark \|\| after(tp->snd_una, tp->frto_highmark)))
		tcp_update_reordering(sk, tp->fackets_out - reord, 0);

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