tcp: update snd_congestion only during congestion
If running without sacks, if snd_una does not cover snd_congestion fast
recovery can be missed but the two heuristics from RFC6582 should avoid
that.
Also snd_congestion was used as a means of inferring if the connection
recently exited congestion while setting the persist timer but that does
not always work correctly if not congested.
Type: fix
Signed-off-by: Florin Coras <fcoras@cisco.com>
Change-Id: I94d4ac738cdd4f7f23f62e97dd63059de1cd4af9
diff --git a/src/vnet/tcp/tcp_timer.h b/src/vnet/tcp/tcp_timer.h
index 5f14a71..7f7dbf1 100644
--- a/src/vnet/tcp/tcp_timer.h
+++ b/src/vnet/tcp/tcp_timer.h
@@ -51,6 +51,13 @@
timer_id, interval);
}
+always_inline u8
+tcp_timer_is_active (tcp_connection_t *tc, tcp_timers_e timer)
+{
+ return tc->timers[timer] != TCP_TIMER_HANDLE_INVALID ||
+ (tc->pending_timers & (1 << timer));
+}
+
always_inline void
tcp_retransmit_timer_set (tcp_timer_wheel_t * tw, tcp_connection_t * tc)
{
@@ -74,19 +81,6 @@
}
always_inline void
-tcp_persist_timer_update (tcp_timer_wheel_t * tw, tcp_connection_t * tc)
-{
- u32 interval;
-
- if (seq_leq (tc->snd_una, tc->snd_congestion + tc->burst_acked))
- interval = 1;
- else
- interval = clib_max ((u32) tc->rto * TCP_TO_TIMER_TICK, 1);
-
- tcp_timer_update (tw, tc, TCP_TIMER_PERSIST, interval);
-}
-
-always_inline void
tcp_persist_timer_reset (tcp_timer_wheel_t * tw, tcp_connection_t * tc)
{
tcp_timer_reset (tw, tc, TCP_TIMER_PERSIST);
@@ -98,21 +92,15 @@
if (tc->snd_una == tc->snd_nxt)
{
tcp_retransmit_timer_reset (tw, tc);
- if (tc->snd_wnd < tc->snd_mss)
- tcp_persist_timer_update (tw, tc);
+ if (tc->snd_wnd < tc->snd_mss &&
+ !tcp_timer_is_active (tc, TCP_TIMER_PERSIST))
+ tcp_persist_timer_set (tw, tc);
}
else
tcp_timer_update (tw, tc, TCP_TIMER_RETRANSMIT,
clib_max ((u32) tc->rto * TCP_TO_TIMER_TICK, 1));
}
-always_inline u8
-tcp_timer_is_active (tcp_connection_t * tc, tcp_timers_e timer)
-{
- return tc->timers[timer] != TCP_TIMER_HANDLE_INVALID
- || (tc->pending_timers & (1 << timer));
-}
-
always_inline void
tcp_timer_expire_timers (tcp_timer_wheel_t * tw, f64 now)
{