[PATCH net-next v3 5/6] net/x25: fix restart request/confirm handling

From: Martin Schiller
Date: Wed Nov 18 2020 - 09:00:42 EST


We have to take the actual link state into account to handle
restart requests/confirms well.

Also, the T20 timer needs to be stopped, if the link is terminated.

Signed-off-by: Martin Schiller <ms@xxxxxxxxxx>
---
net/x25/x25_link.c | 45 +++++++++++++++++++++++++++++++++++++--------
1 file changed, 37 insertions(+), 8 deletions(-)

diff --git a/net/x25/x25_link.c b/net/x25/x25_link.c
index 92828a8a4ada..40ffc10f7a96 100644
--- a/net/x25/x25_link.c
+++ b/net/x25/x25_link.c
@@ -74,16 +74,43 @@ void x25_link_control(struct sk_buff *skb, struct x25_neigh *nb,

switch (frametype) {
case X25_RESTART_REQUEST:
- confirm = !x25_t20timer_pending(nb);
- x25_stop_t20timer(nb);
- nb->state = X25_LINK_STATE_3;
- if (confirm)
+ switch (nb->state) {
+ case X25_LINK_STATE_2:
+ confirm = !x25_t20timer_pending(nb);
+ x25_stop_t20timer(nb);
+ nb->state = X25_LINK_STATE_3;
+ if (confirm)
+ x25_transmit_restart_confirmation(nb);
+ break;
+ case X25_LINK_STATE_3:
+ /* clear existing virtual calls */
+ x25_kill_by_neigh(nb);
+
x25_transmit_restart_confirmation(nb);
+ break;
+ }
break;

case X25_RESTART_CONFIRMATION:
- x25_stop_t20timer(nb);
- nb->state = X25_LINK_STATE_3;
+ switch (nb->state) {
+ case X25_LINK_STATE_2:
+ if (x25_t20timer_pending(nb)) {
+ x25_stop_t20timer(nb);
+ nb->state = X25_LINK_STATE_3;
+ } else {
+ x25_transmit_restart_request(nb);
+ x25_start_t20timer(nb);
+ }
+ break;
+ case X25_LINK_STATE_3:
+ /* clear existing virtual calls */
+ x25_kill_by_neigh(nb);
+
+ x25_transmit_restart_request(nb);
+ nb->state = X25_LINK_STATE_2;
+ x25_start_t20timer(nb);
+ break;
+ }
break;

case X25_DIAGNOSTIC:
@@ -214,8 +241,6 @@ void x25_link_established(struct x25_neigh *nb)
{
switch (nb->state) {
case X25_LINK_STATE_0:
- nb->state = X25_LINK_STATE_2;
- break;
case X25_LINK_STATE_1:
x25_transmit_restart_request(nb);
nb->state = X25_LINK_STATE_2;
@@ -232,6 +257,10 @@ void x25_link_established(struct x25_neigh *nb)
void x25_link_terminated(struct x25_neigh *nb)
{
nb->state = X25_LINK_STATE_0;
+
+ if (x25_t20timer_pending(nb))
+ x25_stop_t20timer(nb);
+
/* Out of order: clear existing virtual calls (X.25 03/93 4.6.3) */
x25_kill_by_neigh(nb);
}
--
2.20.1