tipc: Fix minor bugs in link session number handling
This patch introduces a new, out-of-range value to indicate that
a link endpoint does not have an existing session established
with its peer, eliminating the risk that the previously used
"invalid session number" value (i.e. zero) might eventually be
assigned as a valid session number and cause incorrect link
behavior.
The patch also introduces explicit bit masking when assigning a
new link session number to ensure it does not exceed 16 bits.
Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/tipc/link.c b/net/tipc/link.c
index bd206eb..b8c1231 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -51,6 +51,12 @@
/*
+ * Out-of-range value for link session numbers
+ */
+
+#define INVALID_SESSION 0x10000
+
+/*
* Limit for deferred reception queue:
*/
@@ -464,7 +470,7 @@
msg = l_ptr->pmsg;
msg_init(msg, LINK_PROTOCOL, RESET_MSG, TIPC_OK, INT_H_SIZE, l_ptr->addr);
msg_set_size(msg, sizeof(l_ptr->proto_msg));
- msg_set_session(msg, tipc_random);
+ msg_set_session(msg, (tipc_random & 0xffff));
msg_set_bearer_id(msg, b_ptr->identity);
strcpy((char *)msg_data(msg), if_name);
@@ -705,10 +711,10 @@
u32 checkpoint = l_ptr->next_in_no;
int was_active_link = tipc_link_is_active(l_ptr);
- msg_set_session(l_ptr->pmsg, msg_session(l_ptr->pmsg) + 1);
+ msg_set_session(l_ptr->pmsg, ((msg_session(l_ptr->pmsg) + 1) & 0xffff));
- /* Link is down, accept any session: */
- l_ptr->peer_session = 0;
+ /* Link is down, accept any session */
+ l_ptr->peer_session = INVALID_SESSION;
/* Prepare for max packet size negotiation */
link_init_max_pkt(l_ptr);
@@ -2275,7 +2281,8 @@
switch (msg_type(msg)) {
case RESET_MSG:
- if (!link_working_unknown(l_ptr) && l_ptr->peer_session) {
+ if (!link_working_unknown(l_ptr) &&
+ (l_ptr->peer_session != INVALID_SESSION)) {
if (msg_session(msg) == l_ptr->peer_session) {
dbg("Duplicate RESET: %u<->%u\n",
msg_session(msg), l_ptr->peer_session);
