[PATCH AUTOSEL 4.14 45/66] net/lapb: fix t1 timer handling for LAPB_STATE_0

Sasha Levin
2020-12-23T02:38:56Z

From: Martin Schiller <ms@dev.tdt.de>

[ Upstream commit 62480b992ba3fb1d7260b11293aed9d6557831c7 ]

1. DTE interface changes immediately to LAPB_STATE_1 and start sending
SABM(E).

2. DCE interface sends N2-times DM and changes to LAPB_STATE_1
afterwards if there is no response in the meantime.

Signed-off-by: Martin Schiller <ms@dev.tdt.de>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/lapb/lapb_timer.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/net/lapb/lapb_timer.c b/net/lapb/lapb_timer.c
index 1a5535bc3b8d8..57882eb654c07 100644
--- a/net/lapb/lapb_timer.c
+++ b/net/lapb/lapb_timer.c
@@ -92,11 +92,18 @@ static void lapb_t1timer_expiry(unsigned long param)
switch (lapb->state) {

/*
- * If we are a DCE, keep going DM .. DM .. DM
+ * If we are a DCE, send DM up to N2 times, then switch to
+ * STATE_1 and send SABM(E).
*/
case LAPB_STATE_0:
- if (lapb->mode & LAPB_DCE)
+ if (lapb->mode & LAPB_DCE &&
+ lapb->n2count != lapb->n2) {
+ lapb->n2count++;
lapb_send_control(lapb, LAPB_DM, LAPB_POLLOFF, LAPB_RESPONSE);
+ } else {
+ lapb->state = LAPB_STATE_1;
+ lapb_establish_data_link(lapb);
+ }
break;

/*
--
2.27.0