[bgpd] Fix 0.99 shutdown regression, introduce Clearing and Deleted states
2006-09-14 Paul Jakma <paul.jakma@sun.com>
* (general) Fix some niggly issues around 'shutdown' and clearing
by adding a Clearing FSM wait-state and a hidden 'Deleted'
FSM state, to allow deleted peers to 'cool off' and hit 0
references. This introduces a slow memory leak of struct peer,
however that's more a testament to the fragility of the
reference counting than a bug in this patch, cleanup of
reference counting to fix this is to follow.
* bgpd.h: Add Clearing, Deleted states and Clearing_Completed
and event.
* bgp_debug.c: (bgp_status_msg[]) Add strings for Clearing and
Deleted.
* bgp_fsm.h: Don't allow timer/event threads to set anything
for Deleted peers.
* bgp_fsm.c: (bgp_timer_set) Add Clearing and Deleted. Deleted
needs to stop everything.
(bgp_stop) Remove explicit fsm_change_status call, the
general framework handles the transition.
(bgp_start) Log a warning if a start is attempted on a peer
that should stay down, trying to start a peer.
(struct .. FSM) Add Clearing_Completed
events, has little influence except when in state
Clearing to signal wait-state can end.
Add Clearing and Deleted states, former is a wait-state,
latter is a placeholder state to allow peers to disappear
quietly once refcounts settle.
(bgp_event) Try reduce verbosity of FSM state-change debug,
changes to same state are not interesting (Established->Established)
Allow NULL action functions in FSM.
* bgp_packet.c: (bgp_write) Use FSM events, rather than trying
to twiddle directly with FSM state behind the back of FSM.
(bgp_write_notify) ditto.
(bgp_read) Remove the vague ACCEPT_PEER peer_unlock, or else
this patch crashes, now it leaks instead.
* bgp_route.c: (bgp_clear_node_complete) Clearing_Completed
event, to end clearing.
(bgp_clear_route) See extensive comments.
* bgpd.c: (peer_free) should only be called while in Deleted,
peer refcounting controls when peer_free is called.
bgp_sync_delete should be here, not in peer_delete.
(peer_delete) Initiate delete.
Transition to Deleted state manually.
When removing peer from indices that provide visibility of it,
take great care to be idempotent wrt the reference counting
of struct peer through those indices.
Use bgp_timer_set, rather than replicating.
Call to bgp_sync_delete isn't appropriate here, sync can be
referenced while shutting down and finishing deletion.
(peer_group_bind) Take care to be idempotent wrt list references
indexing peers.
diff --git a/bgpd/bgpd.h b/bgpd/bgpd.h
index b8ae30a..8b180a4 100644
--- a/bgpd/bgpd.h
+++ b/bgpd/bgpd.h
@@ -386,7 +386,6 @@
#define PEER_STATUS_GROUP (1 << 4) /* peer-group conf */
#define PEER_STATUS_NSF_MODE (1 << 5) /* NSF aware peer */
#define PEER_STATUS_NSF_WAIT (1 << 6) /* wait comeback peer */
-#define PEER_STATUS_CLEARING (1 << 7) /* peers table being cleared */
/* Peer status af flags (reset in bgp_stop) */
u_int16_t af_sflags[AFI_MAX][SAFI_MAX];
@@ -662,7 +661,9 @@
#define OpenSent 4
#define OpenConfirm 5
#define Established 6
-#define BGP_STATUS_MAX 7
+#define Clearing 7
+#define Deleted 8
+#define BGP_STATUS_MAX 9
/* BGP finite state machine events. */
#define BGP_Start 1
@@ -678,7 +679,8 @@
#define Receive_KEEPALIVE_message 11
#define Receive_UPDATE_message 12
#define Receive_NOTIFICATION_message 13
-#define BGP_EVENTS_MAX 14
+#define Clearing_Completed 14
+#define BGP_EVENTS_MAX 15
/* BGP timers default value. */
#define BGP_INIT_START_TIMER 5