Default tables are not created unless actually used.

This allows for setting default table values at the beginning of config
file before "master4" and "master6" tables are initialized.

5 files changed, 51 insertions, 14 deletions

diff --git a/nest/config.Y b/nest/config.Y
index 91147a29..4bf0fefe 100644
--- a/nest/config.Y
+++ b/nest/config.Y
@@ -361,7 +361,11 @@ channel_end:
 proto_channel: channel_start channel_opt_list channel_end;
 
 
-rtable: CF_SYM_KNOWN { cf_assert_symbol($1, SYM_TABLE); $$ = $1->table; } ;
+rtable: CF_SYM_KNOWN {
+  cf_assert_symbol($1, SYM_TABLE);
+  if (!$1->table) rt_new_default_table($1);
+  $$ = $1->table;
+} ;
 
 imexport:
    FILTER filter { $$ = $2; }
@@ -683,6 +687,7 @@ r_args:
    }
 | r_args TABLE symbol_known {
      cf_assert_symbol($3, SYM_TABLE);
+     if (!$3->table) cf_error("Table %s not configured", $3->name);
      $$ = $1;
      rt_show_add_table($$, $3->table->table);
      $$->tables_defined_by = RSD_TDB_DIRECT;
diff --git a/nest/proto.c b/nest/proto.c
index 853b1cf9..ef3e3f4d 100644
--- a/nest/proto.c
+++ b/nest/proto.c
@@ -864,7 +864,7 @@ channel_config_new(const struct channel_class *cc, const char *name, uint net_ty
     if (proto->net_type && (net_type != proto->net_type))
       cf_error("Different channel type");
 
-    tab = new_config->def_tables[net_type];
+    tab = rt_get_default_table(new_config, net_type);
   }
 
   if (!cc)
diff --git a/nest/rt-show.c b/nest/rt-show.c
index 17400029..5d7723cf 100644
--- a/nest/rt-show.c
+++ b/nest/rt-show.c
@@ -400,8 +400,8 @@ rt_show_get_default_tables(struct rt_show_data *d)
   }
 
   for (int i=1; i<NET_MAX; i++)
-    if (config->def_tables[i] && config->def_tables[i]->table)
-      rt_show_add_table(d, config->def_tables[i]->table);
+    if (config->def_tables[i] && config->def_tables[i]->table && config->def_tables[i]->table->table)
+      rt_show_add_table(d, config->def_tables[i]->table->table);
 }
 
 static inline void
diff --git a/nest/rt-table.c b/nest/rt-table.c
index 8e1e03fb..f0552965 100644
--- a/nest/rt-table.c
+++ b/nest/rt-table.c
@@ -3094,8 +3094,8 @@ rt_preconfig(struct config *c)
 {
   init_list(&c->tables);
 
-  rt_new_table(cf_get_symbol("master4"), NET_IP4);
-  rt_new_table(cf_get_symbol("master6"), NET_IP6);
+  c->def_tables[NET_IP4] = cf_define_symbol(cf_get_symbol("master4"), SYM_TABLE, table, NULL);
+  c->def_tables[NET_IP6] = cf_define_symbol(cf_get_symbol("master6"), SYM_TABLE, table, NULL);
 }
 
 void
@@ -3110,6 +3110,13 @@ rt_postconfig(struct config *c)
   WALK_LIST(rc, c->tables)
     if (rc->gc_period == (uint) -1)
       rc->gc_period = (uint) def_gc_period;
+
+  for (uint net_type = 0; net_type < NET_MAX; net_type++)
+    if (c->def_tables[net_type] && !c->def_tables[net_type]->table)
+    {
+      c->def_tables[net_type]->class = SYM_VOID;
+      c->def_tables[net_type] = NULL;
+    }
 }
 
 
@@ -3584,19 +3591,42 @@ rt_next_hop_update(rtable *tab)
     ev_schedule(tab->rt_event);
 }
 
+void
+rt_new_default_table(struct symbol *s)
+{
+  for (uint addr_type = 0; addr_type < NET_MAX; addr_type++)
+    if (s == new_config->def_tables[addr_type])
+    {
+      s->table = rt_new_table(s, addr_type);
+      return;
+    }
+
+  bug("Requested an unknown new default table: %s", s->name);
+}
+
+struct rtable_config *
+rt_get_default_table(struct config *cf, uint addr_type)
+{
+  struct symbol *ts = cf->def_tables[addr_type];
+  if (!ts)
+    return NULL;
+
+  if (!ts->table)
+    rt_new_default_table(ts);
+
+  return ts->table;
+}
 
 struct rtable_config *
 rt_new_table(struct symbol *s, uint addr_type)
 {
-  /* Hack that allows to 'redefine' the master table */
-  if ((s->class == SYM_TABLE) &&
-      (s->table == new_config->def_tables[addr_type]) &&
-      ((addr_type == NET_IP4) || (addr_type == NET_IP6)))
-    return s->table;
-
   struct rtable_config *c = cfg_allocz(sizeof(struct rtable_config));
 
-  cf_define_symbol(s, SYM_TABLE, table, c);
+  if (s == new_config->def_tables[addr_type])
+    s->table = c;
+  else
+    cf_define_symbol(s, SYM_TABLE, table, c);
+
   c->name = s->name;
   c->addr_type = addr_type;
   c->gc_threshold = 1000;
@@ -3610,7 +3640,7 @@ rt_new_table(struct symbol *s, uint addr_type)
 
   /* First table of each type is kept as default */
   if (! new_config->def_tables[addr_type])
-    new_config->def_tables[addr_type] = c;
+    new_config->def_tables[addr_type] = s;
 
   return c;
 }
diff --git a/nest/rt.h b/nest/rt.h
index 1a6b7a93..f5cf9457 100644
--- a/nest/rt.h
+++ b/nest/rt.h
@@ -481,6 +481,8 @@ void rt_reload_channel_abort(struct channel *c);
 void rt_refeed_channel(struct channel *c);
 void rt_prune_sync(rtable *t, int all);
 struct rtable_config *rt_new_table(struct symbol *s, uint addr_type);
+void rt_new_default_table(struct symbol *s);
+struct rtable_config *rt_get_default_table(struct config *cf, uint addr_type);
 
 static inline int rt_is_ip(rtable *tab)
 { return (tab->addr_type == NET_IP4) || (tab->addr_type == NET_IP6); }