diff options
Diffstat (limited to 'nest/proto.c')
| -rw-r--r-- | nest/proto.c | 154 |
1 files changed, 114 insertions, 40 deletions
diff --git a/nest/proto.c b/nest/proto.c index 2bc3e319..e990b48f 100644 --- a/nest/proto.c +++ b/nest/proto.c @@ -51,6 +51,8 @@ static char *c_states[] = { "HUNGRY", "???", "HAPPY", "FLUSHING" }; static void proto_flush_loop(void *); static void proto_shutdown_loop(struct timer *); static void proto_rethink_goal(struct proto *p); +static void proto_want_export_up(struct proto *p); +static void proto_fell_down(struct proto *p); static char *proto_state_name(struct proto *p); static void @@ -151,21 +153,20 @@ extern pool *rt_table_pool; * @t: routing table to connect to * @stats: per-table protocol statistics * - * This function creates a connection between the protocol instance @p - * and the routing table @t, making the protocol hear all changes in - * the table. + * This function creates a connection between the protocol instance @p and the + * routing table @t, making the protocol hear all changes in the table. * - * The announce hook is linked in the protocol ahook list and, if the - * protocol accepts routes, also in the table ahook list. Announce - * hooks are allocated from the routing table resource pool, they are - * unlinked from the table ahook list after the protocol went down, - * (in proto_schedule_flush()) and they are automatically freed after the - * protocol is flushed (in proto_fell_down()). + * The announce hook is linked in the protocol ahook list. Announce hooks are + * allocated from the routing table resource pool and when protocol accepts + * routes also in the table ahook list. The are linked to the table ahook list + * and unlinked from it depending on export_state (in proto_want_export_up() and + * proto_want_export_down()) and they are automatically freed after the protocol + * is flushed (in proto_fell_down()). * - * Unless you want to listen to multiple routing tables (as the Pipe - * protocol does), you needn't to worry about this function since the - * connection to the protocol's primary routing table is initialized - * automatically by the core code. + * Unless you want to listen to multiple routing tables (as the Pipe protocol + * does), you needn't to worry about this function since the connection to the + * protocol's primary routing table is initialized automatically by the core + * code. */ struct announce_hook * proto_add_announce_hook(struct proto *p, struct rtable *t, struct proto_stats *stats) @@ -183,7 +184,7 @@ proto_add_announce_hook(struct proto *p, struct rtable *t, struct proto_stats *s h->next = p->ahooks; p->ahooks = h; - if (p->rt_notify && (p->export_state == ES_READY)) + if (p->rt_notify && (p->export_state != ES_DOWN)) add_tail(&t->hooks, &h->n); return h; } @@ -659,16 +660,59 @@ proto_rethink_goal(struct proto *p) } +/** + * DOC: Graceful restart recovery + * + * Graceful restart of a router is a process when the routing plane (e.g. BIRD) + * restarts but both the forwarding plane (e.g kernel routing table) and routing + * neighbors keep proper routes, and therefore uninterrupted packet forwarding + * is maintained. + * + * BIRD implements graceful restart recovery by deferring export of routes to + * protocols until routing tables are refilled with the expected content. After + * start, protocols generate routes as usual, but routes are not propagated to + * them, until protocols report that they generated all routes. After that, + * graceful restart recovery is finished and the export (and the initial feed) + * to protocols is enabled. + * + * When graceful restart recovery need is detected during initialization, then + * enabled protocols are marked with @gr_recovery flag before start. Such + * protocols then decide how to proceed with graceful restart, participation is + * voluntary. Protocols could lock the recovery by proto_graceful_restart_lock() + * (stored in @gr_lock flag), which means that they want to postpone the end of + * the recovery until they converge and then unlock it. They also could set + * @gr_wait before advancing to %PS_UP, which means that the core should defer + * route export to that protocol until the end of the recovery. This should be + * done by protocols that expect their neigbors to keep the proper routes + * (kernel table, BGP sessions with BGP graceful restart capability). + * + * The graceful restart recovery is finished when either all graceful restart + * locks are unlocked or when graceful restart wait timer fires. + * + */ -static void graceful_restart_done(struct timer *t UNUSED); -static void proto_want_export_up(struct proto *p); +static void graceful_restart_done(struct timer *t); +/** + * graceful_restart_recovery - request initial graceful restart recovery + * + * Called by the platform initialization code if the need for recovery + * after graceful restart is detected during boot. Have to be called + * before protos_commit(). + */ void graceful_restart_recovery(void) { graceful_restart_state = GRS_INIT; } +/** + * graceful_restart_init - initialize graceful restart + * + * When graceful restart recovery was requested, the function starts an active + * phase of the recovery and initializes graceful restart wait timer. The + * function have to be called after protos_commit(). + */ void graceful_restart_init(void) { @@ -689,6 +733,15 @@ graceful_restart_init(void) tm_start(gr_wait_timer, config->gr_wait); } +/** + * graceful_restart_done - finalize graceful restart + * + * When there are no locks on graceful restart, the functions finalizes the + * graceful restart recovery. Protocols postponing route export until the end of + * the recovery are awakened and the export to them is enabled. All other + * related state is cleared. The function is also called when the graceful + * restart wait timer fires (but there are still some locks). + */ static void graceful_restart_done(struct timer *t UNUSED) { @@ -727,7 +780,19 @@ graceful_restart_show_status(void) cli_msg(-24, " Wait timer is %d/%d", tm_remains(gr_wait_timer), config->gr_wait); } -/* Just from start hook */ +/** + * proto_graceful_restart_lock - lock graceful restart by protocol + * @p: protocol instance + * + * This function allows a protocol to postpone the end of graceful restart + * recovery until it converges. The lock is removed when the protocol calls + * proto_graceful_restart_unlock() or when the protocol is stopped. + * + * The function have to be called during the initial phase of graceful restart + * recovery and only for protocols that are part of graceful restart (i.e. their + * @gr_recovery is set), which means it should be called from protocol start + * hooks. + */ void proto_graceful_restart_lock(struct proto *p) { @@ -741,6 +806,13 @@ proto_graceful_restart_lock(struct proto *p) graceful_restart_locks++; } +/** + * proto_graceful_restart_unlock - unlock graceful restart by protocol + * @p: protocol instance + * + * This function unlocks a lock from proto_graceful_restart_lock(). It is also + * automatically called when the lock holding protocol went down. + */ void proto_graceful_restart_unlock(struct proto *p) { @@ -867,29 +939,6 @@ protos_build(void) proto_flush_event->hook = proto_flush_loop; proto_shutdown_timer = tm_new(proto_pool); proto_shutdown_timer->hook = proto_shutdown_loop; - proto_shutdown_timer = tm_new(proto_pool); - proto_shutdown_timer->hook = proto_shutdown_loop; -} - -static void -proto_fell_down(struct proto *p) -{ - DBG("Protocol %s down\n", p->name); - - u32 all_routes = p->stats.imp_routes + p->stats.filt_routes; - if (all_routes != 0) - log(L_ERR "Protocol %s is down but still has %d routes", p->name, all_routes); - - bzero(&p->stats, sizeof(struct proto_stats)); - proto_free_ahooks(p); - - if (! p->proto->multitable) - rt_unlock_table(p->table); - - if (p->proto->cleanup) - p->proto->cleanup(p); - - proto_rethink_goal(p); } static void @@ -1066,6 +1115,10 @@ proto_request_feeding(struct proto *p) { ASSERT(p->proto_state == PS_UP); + /* Do nothing if we are still waiting for feeding */ + if (p->export_state == ES_DOWN) + return; + /* If we are already feeding, we want to restart it */ if (p->export_state == ES_FEEDING) { @@ -1220,6 +1273,27 @@ proto_falling_down(struct proto *p) proto_graceful_restart_unlock(p); } +static void +proto_fell_down(struct proto *p) +{ + DBG("Protocol %s down\n", p->name); + + u32 all_routes = p->stats.imp_routes + p->stats.filt_routes; + if (all_routes != 0) + log(L_ERR "Protocol %s is down but still has %d routes", p->name, all_routes); + + bzero(&p->stats, sizeof(struct proto_stats)); + proto_free_ahooks(p); + + if (! p->proto->multitable) + rt_unlock_table(p->table); + + if (p->proto->cleanup) + p->proto->cleanup(p); + + proto_rethink_goal(p); +} + /** * proto_notify_state - notify core about protocol state change |