BGP: implement Adj-RIB-In

The patch implements optional internal import table to a channel and
hooks it to BGP so it can be used as Adj-RIB-In. When enabled, all
received (pre-filtered) routes are stored there and import filters can
be re-evaluated without explicit route refresh. An import table can be
examined using e.g. 'show route import table bgp1.ipv4'.

1 files changed, 121 insertions, 0 deletions

diff --git a/nest/rt-table.c b/nest/rt-table.c
index 21b6622e..5beb1be9 100644
--- a/nest/rt-table.c
+++ b/nest/rt-table.c
@@ -2288,6 +2288,127 @@ rt_feed_channel_abort(struct channel *c)
     }
 }
 
+
+int
+rte_update_in(struct channel *c, const net_addr *n, rte *new, struct rte_src *src)
+{
+  rte *old, **pos;
+  net *net;
+
+  if (new)
+  {
+    net = net_get(c->in_table, n);
+
+    if (!new->pref)
+      new->pref = c->preference;
+
+    if (!rta_is_cached(new->attrs))
+      new->attrs = rta_lookup(new->attrs);
+  }
+  else
+  {
+    net = net_find(c->in_table, n);
+
+    if (!net)
+      return 0;
+  }
+
+  /* Find the old rte */
+  for (pos = &net->routes; old = *pos; pos = &old->next)
+    if (old->attrs->src == src)
+    {
+      if (new && rte_same(old, new))
+	return 0;
+
+      /* Remove the old rte */
+      *pos = old->next;
+      rte_free_quick(old);
+
+      break;
+    }
+
+  if (!new)
+    return !!old;
+
+  /* Insert the new rte */
+  rte *e = rte_do_cow(new);
+  e->flags |= REF_COW;
+  e->net = net;
+  e->sender = c;
+  e->lastmod = current_time();
+  e->next = *pos;
+  *pos = e;
+
+  return 1;
+}
+
+int
+rt_reload_channel(struct channel *c)
+{
+  struct rtable *tab = c->in_table;
+  struct fib_iterator *fit = &c->reload_fit;
+  int max_feed = 64;
+
+  ASSERT(c->channel_state == CS_UP);
+
+  if (!c->reload_active)
+  {
+    FIB_ITERATE_INIT(fit, &tab->fib);
+    c->reload_active = 1;
+  }
+
+  FIB_ITERATE_START(&tab->fib, fit, net, n)
+  {
+    if (max_feed <= 0)
+    {
+      FIB_ITERATE_PUT(fit);
+      return 0;
+    }
+
+    for (rte *e = n->routes; e; e = e->next)
+    {
+      rte_update2(c, n->n.addr, rte_do_cow(e), e->attrs->src);
+      max_feed--;
+    }
+  }
+  FIB_ITERATE_END;
+
+  c->reload_active = 0;
+  return 1;
+}
+
+void
+rt_reload_channel_abort(struct channel *c)
+{
+  if (c->reload_active)
+  {
+    /* Unlink the iterator */
+    fit_get(&c->in_table->fib, &c->reload_fit);
+    c->reload_active = 0;
+  }
+}
+
+void
+rt_prune_sync(rtable *t, int all)
+{
+  FIB_WALK(&t->fib, net, n)
+  {
+    rte *e, **ee = &n->routes;
+    while (e = *ee)
+    {
+      if (all || (e->flags & (REF_STALE | REF_DISCARD)))
+      {
+	*ee = e->next;
+	rte_free_quick(e);
+      }
+      else
+	ee = &e->next;
+    }
+  }
+  FIB_WALK_END;
+}
+
+
 static inline u32
 hc_hash(ip_addr a, rtable *dep)
 {