From dd786e338c4adccee7077c8ecfaf56df2831ee4c Mon Sep 17 00:00:00 2001
From: Maria Matejka <mq@ucw.cz>
Date: Thu, 1 Sep 2022 10:39:56 +0200
Subject: ROA subscriptions are also converted to export requests.

By this, the requesting channels do the timers in their own loops,
avoiding unnecessary synchronization when the central timer went off.

This is of course less effective for now, yet it allows to easily
implement selective reloads in future.
---
 nest/rt-table.c | 96 ++++-----------------------------------------------------
 1 file changed, 6 insertions(+), 90 deletions(-)

(limited to 'nest/rt-table.c')

diff --git a/nest/rt-table.c b/nest/rt-table.c
index 72f85370..2fa736e2 100644
--- a/nest/rt-table.c
+++ b/nest/rt-table.c
@@ -82,9 +82,8 @@
  * will be re-validated later in this round anyway.
  *
  * The third mechanism is used for RPKI re-validation of IP routes and it is the
- * simplest. It is just a list of subscribers in src table, who are notified
- * when any change happened, but only after a settle time. Also, in RPKI case
- * the dst is not a table, but a channel, who refeeds routes through a filter.
+ * simplest. It is also an auxiliary export request belonging to the
+ * appropriate channel, triggering its reload/refeed timer after a settle time.
  */
 
 #undef LOCAL_DEBUG
@@ -134,7 +133,6 @@ static void rt_next_hop_update(rtable *tab);
 static inline void rt_next_hop_resolve_rte(rte *r);
 static inline void rt_flowspec_resolve_rte(rte *r, struct channel *c);
 static inline void rt_prune_table(rtable *tab);
-static inline void rt_schedule_notify(rtable *tab);
 static void rt_kick_prune_timer(rtable *tab);
 static void rt_feed_by_fib(void *);
 static void rt_feed_by_trie(void *);
@@ -1270,15 +1268,10 @@ rte_announce(rtable *tab, net *net, struct rte_storage *new, struct rte_storage
   if ((new == old) && (new_best == old_best))
     return;
 
-  if (new_best_valid || old_best_valid)
-  {
-    if (new_best_valid)
-      new_best->rte.sender->stats.pref++;
-    if (old_best_valid)
-      old_best->rte.sender->stats.pref--;
-  }
-
-  rt_schedule_notify(tab);
+  if (new_best_valid)
+    new_best->rte.sender->stats.pref++;
+  if (old_best_valid)
+    old_best->rte.sender->stats.pref--;
 
   if (EMPTY_LIST(tab->exporter.hooks) && EMPTY_LIST(tab->exporter.pending))
   {
@@ -2371,78 +2364,6 @@ rt_kick_prune_timer(rtable *tab)
 }
 
 
-static inline btime
-rt_settled_time(rtable *tab)
-{
-  ASSUME(tab->base_settle_time != 0);
-
-  return MIN(tab->last_rt_change + tab->config->min_settle_time,
-	     tab->base_settle_time + tab->config->max_settle_time);
-}
-
-static void
-rt_settle_timer(timer *t)
-{
-  rtable *tab = t->data;
-
-  if (!tab->base_settle_time)
-    return;
-
-  btime settled_time = rt_settled_time(tab);
-  if (current_time() < settled_time)
-  {
-    tm_set(tab->settle_timer, settled_time);
-    return;
-  }
-
-  /* Settled */
-  tab->base_settle_time = 0;
-
-  struct rt_subscription *s;
-  WALK_LIST(s, tab->subscribers)
-    ev_send(s->list, s->event);
-}
-
-static void
-rt_kick_settle_timer(rtable *tab)
-{
-  tab->base_settle_time = current_time();
-
-  if (!tab->settle_timer)
-    tab->settle_timer = tm_new_init(tab->rp, rt_settle_timer, tab, 0, 0);
-
-  if (!tm_active(tab->settle_timer))
-    tm_set(tab->settle_timer, rt_settled_time(tab));
-}
-
-static inline void
-rt_schedule_notify(rtable *tab)
-{
-  if (EMPTY_LIST(tab->subscribers))
-    return;
-
-  if (tab->base_settle_time)
-    return;
-
-  rt_kick_settle_timer(tab);
-}
-
-void
-rt_subscribe(rtable *tab, struct rt_subscription *s)
-{
-  s->tab = tab;
-  rt_lock_table(tab);
-  DBG("rt_subscribe(%s)\n", tab->name);
-  add_tail(&tab->subscribers, &s->n);
-}
-
-void
-rt_unsubscribe(struct rt_subscription *s)
-{
-  rem_node(&s->n);
-  rt_unlock_table(s->tab);
-}
-
 static void
 rt_flowspec_export_one(struct rt_export_request *req, const net_addr *net, struct rt_pending_export *first)
 {
@@ -2580,7 +2501,6 @@ rt_free(resource *_r)
   fib_free(&r->fib);
   hmap_free(&r->id_map);
   rfree(r->rt_event);
-  rfree(r->settle_timer);
   mb_free(r);
   */
 }
@@ -2642,8 +2562,6 @@ rt_setup(pool *pp, struct rtable_config *cf)
   hmap_init(&t->id_map, p, 1024);
   hmap_set(&t->id_map, 0);
 
-  init_list(&t->subscribers);
-
   t->rt_event = ev_new_init(p, rt_event, t);
   t->uncork_event = ev_new_init(p, rt_uncork_event, t);
   t->prune_timer = tm_new_init(p, rt_prune_timer, t, 0, 0);
@@ -3629,8 +3547,6 @@ rt_new_table(struct symbol *s, uint addr_type)
   c->addr_type = addr_type;
   c->gc_threshold = 1000;
   c->gc_period = (uint) -1;	/* set in rt_postconfig() */
-  c->min_settle_time = 1 S;
-  c->max_settle_time = 20 S;
   c->cork_threshold.low = 128;
   c->cork_threshold.high = 512;
   c->debug = new_config->table_debug;
-- 
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