Commit e1cd8f78 authored Nov 14, 2007 by Ilpo Jrvinen Committed by David S. Miller Nov 14, 2007

[TCP] FRTO: Clear frto_highmark only after process_frto that uses it



I broke this in commit 3de96471:

	[TCP]: Wrap-safed reordering detection FRTO check

tcp_process_frto should always see a valid frto_highmark. An invalid
frto_highmark (zero) is very likely what ultimately caused a seqno
compare in tcp_frto_enter_loss to do the wrong leading to the LOST-bit
leak.

Having LOST-bits integry ensured like done after commit
23aeeec3:

	[TCP] FRTO: Plug potential LOST-bit leak

won't hurt. It may still be useful in some other, possibly legimate,
scenario.

Reported by Chazarain Guillaume <guichaz@yahoo.fr>.

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

parent c67625a1

net/ipv4/tcp_input.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -3113,11 +3113,11 @@ static int tcp_ack(struct sock sk, struct sk_buff skb, int flag)
		/* See if we can take anything off of the retransmit queue. */
		flag \|= tcp_clean_rtx_queue(sk, &seq_rtt, prior_fackets);

		if (tp->frto_counter)
		frto_cwnd = tcp_process_frto(sk, flag);
		/* Guarantee sacktag reordering detection against wrap-arounds */
		if (before(tp->frto_highmark, tp->snd_una))
		tp->frto_highmark = 0;
		if (tp->frto_counter)
		frto_cwnd = tcp_process_frto(sk, flag);

		if (tcp_ack_is_dubious(sk, flag)) {
		/* Advance CWND, if state allows this. */