From a686e6859e976712e28f6af927cd52a6a3bb372a Mon Sep 17 00:00:00 2001 From: Allan Stephens Date: Wed, 4 Jun 2008 17:29:39 -0700 Subject: [PATCH] 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 Signed-off-by: David S. Miller --- net/tipc/link.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/net/tipc/link.c b/net/tipc/link.c index bd206ebe4e..b8c1231e31 100644 --- a/net/tipc/link.c +++ b/net/tipc/link.c @@ -50,6 +50,12 @@ #include "bcast.h" +/* + * Out-of-range value for link session numbers + */ + +#define INVALID_SESSION 0x10000 + /* * Limit for deferred reception queue: */ @@ -464,7 +470,7 @@ struct link *tipc_link_create(struct bearer *b_ptr, const u32 peer, 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 @@ void tipc_link_reset(struct link *l_ptr) 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 @@ static void link_recv_proto_msg(struct link *l_ptr, struct sk_buff *buf) 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); -- 2.39.5