[TCP] FRTO: Clear frto_highmark only after process_frto that uses it
I broke this in commit 3de96471bd7fb76406e975ef6387abe3a0698149:
[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
23aeeec365dcf8bc87fae44c533e50d0bb4f23cc:
[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 Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 3f126ec..0f0c1c9 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -3113,11 +3113,11 @@
/* 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. */