From 5a68d5ee000bb784c4856391b4861739c8bbd341 Mon Sep 17 00:00:00 2001 From: Allan Stephens Date: Tue, 17 Aug 2010 11:00:16 +0000 Subject: [PATCH] tipc: Prevent missing name table entries when link flip-flops rapidly Ensure that TIPC does not re-establish communication with a neighboring node until it has finished updating all data structures containing information about that node to reflect the earlier loss of contact. Previously, it was possible for TIPC to perform its purge of name table entries relating to the node once contact had already been re-established, resulting in the unwanted removal of valid name table entries. Signed-off-by: Allan Stephens Signed-off-by: Paul Gortmaker Signed-off-by: David S. Miller --- net/tipc/discover.c | 8 ++++++++ net/tipc/link.c | 11 ++++++++++- net/tipc/node.c | 19 +++++++++++++++++++ net/tipc/node.h | 2 ++ 4 files changed, 39 insertions(+), 1 deletion(-) diff --git a/net/tipc/discover.c b/net/tipc/discover.c index fc1fcf5e6b53..f28d1ae93125 100644 --- a/net/tipc/discover.c +++ b/net/tipc/discover.c @@ -203,6 +203,14 @@ void tipc_disc_recv_msg(struct sk_buff *buf, struct bearer *b_ptr) return; } spin_lock_bh(&n_ptr->lock); + + /* Don't talk to neighbor during cleanup after last session */ + + if (n_ptr->cleanup_required) { + spin_unlock_bh(&n_ptr->lock); + return; + } + link = n_ptr->links[b_ptr->identity]; if (!link) { dbg("creating link\n"); diff --git a/net/tipc/link.c b/net/tipc/link.c index 9d18c9b7638b..a6a3102bb4d6 100644 --- a/net/tipc/link.c +++ b/net/tipc/link.c @@ -1869,13 +1869,22 @@ void tipc_recv_msg(struct sk_buff *head, struct tipc_bearer *tb_ptr) goto cont; } - /* Locate unicast link endpoint that should handle message */ + /* Locate neighboring node that sent message */ n_ptr = tipc_node_find(msg_prevnode(msg)); if (unlikely(!n_ptr)) goto cont; tipc_node_lock(n_ptr); + /* Don't talk to neighbor during cleanup after last session */ + + if (n_ptr->cleanup_required) { + tipc_node_unlock(n_ptr); + goto cont; + } + + /* Locate unicast link endpoint that should handle message */ + l_ptr = n_ptr->links[b_ptr->identity]; if (unlikely(!l_ptr)) { tipc_node_unlock(n_ptr); diff --git a/net/tipc/node.c b/net/tipc/node.c index 940851797615..b702c7bf580f 100644 --- a/net/tipc/node.c +++ b/net/tipc/node.c @@ -383,6 +383,20 @@ static void node_established_contact(struct tipc_node *n_ptr) tipc_highest_allowed_slave); } +static void node_cleanup_finished(unsigned long node_addr) +{ + struct tipc_node *n_ptr; + + read_lock_bh(&tipc_net_lock); + n_ptr = tipc_node_find(node_addr); + if (n_ptr) { + tipc_node_lock(n_ptr); + n_ptr->cleanup_required = 0; + tipc_node_unlock(n_ptr); + } + read_unlock_bh(&tipc_net_lock); +} + static void node_lost_contact(struct tipc_node *n_ptr) { struct cluster *c_ptr; @@ -457,6 +471,11 @@ static void node_lost_contact(struct tipc_node *n_ptr) tipc_k_signal((Handler)ns->handle_node_down, (unsigned long)ns->usr_handle); } + + /* Prevent re-contact with node until all cleanup is done */ + + n_ptr->cleanup_required = 1; + tipc_k_signal((Handler)node_cleanup_finished, n_ptr->addr); } /** diff --git a/net/tipc/node.h b/net/tipc/node.h index 6f990da5d143..45f3db3a595d 100644 --- a/net/tipc/node.h +++ b/net/tipc/node.h @@ -52,6 +52,7 @@ * @active_links: pointers to active links to node * @links: pointers to all links to node * @working_links: number of working links to node (both active and standby) + * @cleanup_required: non-zero if cleaning up after a prior loss of contact * @link_cnt: number of links to node * @permit_changeover: non-zero if node has redundant links to this system * @routers: bitmap (used for multicluster communication) @@ -78,6 +79,7 @@ struct tipc_node { struct link *links[MAX_BEARERS]; int link_cnt; int working_links; + int cleanup_required; int permit_changeover; u32 routers[512/32]; int last_router; -- 2.30.2