Implements generalized import hooks.

Thanks to Alexander V. Chernikov for the original patch.

4 files changed, 226 insertions, 25 deletions

diff --git a/nest/config.Y b/nest/config.Y
index f889828a..60b03278 100644
--- a/nest/config.Y
+++ b/nest/config.Y
@@ -44,6 +44,7 @@ CF_DECLS
 
 CF_KEYWORDS(ROUTER, ID, PROTOCOL, TEMPLATE, PREFERENCE, DISABLED, DEBUG, ALL, OFF, DIRECT)
 CF_KEYWORDS(INTERFACE, IMPORT, EXPORT, FILTER, NONE, TABLE, STATES, ROUTES, FILTERS)
+CF_KEYWORDS(EXCEED, LIMIT, WARN, BLOCK, RESTART, DISABLE)
 CF_KEYWORDS(PASSWORD, FROM, PASSIVE, TO, ID, EVENTS, PACKETS, PROTOCOLS, INTERFACES)
 CF_KEYWORDS(PRIMARY, STATS, COUNT, FOR, COMMANDS, PREEXPORT, GENERATE, ROA, MAX, FLUSH)
 CF_KEYWORDS(LISTEN, BGP, V6ONLY, DUAL, ADDRESS, PORT, PASSWORDS, DESCRIPTION)
@@ -64,8 +65,9 @@ CF_ENUM(T_ENUM_ROA, ROA_, UNKNOWN, VALID, INVALID)
 %type <ro> roa_args
 %type <rot> roa_table_arg
 %type <sd> sym_args
-%type <i> proto_start echo_mask echo_size debug_mask debug_list debug_flag mrtdump_mask mrtdump_list mrtdump_flag export_or_preexport roa_mode
+%type <i> proto_start echo_mask echo_size debug_mask debug_list debug_flag mrtdump_mask mrtdump_list mrtdump_flag export_or_preexport roa_mode limit_action
 %type <ps> proto_patt proto_patt2
+%type <g> limit_spec
 
 CF_GRAMMAR
 
@@ -176,6 +178,7 @@ proto_item:
  | MRTDUMP mrtdump_mask { this_proto->mrtdump = $2; }
  | IMPORT imexport { this_proto->in_filter = $2; }
  | EXPORT imexport { this_proto->out_filter = $2; }
+ | IMPORT LIMIT limit_spec { this_proto->in_limit = $3; }
  | TABLE rtable { this_proto->table = $2; }
  | ROUTER ID idval { this_proto->router_id = $3; }
  | DESCRIPTION TEXT { this_proto->dsc = $2; }
@@ -188,6 +191,22 @@ imexport:
  | NONE { $$ = FILTER_REJECT; }
  ;
 
+limit_action:
+   WARN { $$ = PLA_WARN; }
+ | BLOCK { $$ = PLA_BLOCK; }
+ | RESTART { $$ = PLA_RESTART; }
+ | DISABLE { $$ = PLA_DISABLE; }
+ ;
+
+limit_spec:
+   expr EXCEED limit_action {
+     struct proto_limit *l = cfg_allocz(sizeof(struct proto_limit));
+     l->limit = $1;
+     l->action = $3;
+     $$ = l;
+   }
+ ;
+
 rtable:
    SYM {
      if ($1->class != SYM_TABLE) cf_error("Table name expected");
diff --git a/nest/proto.c b/nest/proto.c
index 802d5238..418a7a61 100644
--- a/nest/proto.c
+++ b/nest/proto.c
@@ -34,11 +34,13 @@ static list flush_proto_list;
 static struct proto *initial_device_proto;
 
 static event *proto_flush_event;
+static timer *proto_shutdown_timer;
 
 static char *p_states[] = { "DOWN", "START", "UP", "STOP" };
 static char *c_states[] = { "HUNGRY", "FEEDING", "HAPPY", "FLUSHING" };
 
 static void proto_flush_loop(void *);
+static void proto_shutdown_loop(struct timer *);
 static void proto_rethink_goal(struct proto *p);
 static char *proto_state_name(struct proto *p);
 
@@ -134,8 +136,6 @@ extern pool *rt_table_pool;
  * proto_add_announce_hook - connect protocol to a routing table
  * @p: protocol instance
  * @t: routing table to connect to
- * @in: input filter
- * @out: output filter
  * @stats: per-table protocol statistics
  *
  * This function creates a connection between the protocol instance @p
@@ -155,8 +155,7 @@ extern pool *rt_table_pool;
  * automatically by the core code.
  */
 struct announce_hook *
-proto_add_announce_hook(struct proto *p, struct rtable *t, struct filter *in,
-			struct filter *out, struct proto_stats *stats)
+proto_add_announce_hook(struct proto *p, struct rtable *t, struct proto_stats *stats)
 {
   struct announce_hook *h;
 
@@ -166,8 +165,6 @@ proto_add_announce_hook(struct proto *p, struct rtable *t, struct filter *in,
   h = mb_allocz(rt_table_pool, sizeof(struct announce_hook));
   h->table = t;
   h->proto = p;
-  h->in_filter = in;
-  h->out_filter = out;
   h->stats = stats;
 
   h->next = p->ahooks;
@@ -414,6 +411,8 @@ proto_reconfigure(struct proto *p, struct proto_config *oc, struct proto_config
     {
       p->main_ahook->in_filter = nc->in_filter;
       p->main_ahook->out_filter = nc->out_filter;
+      p->main_ahook->in_limit = nc->in_limit;
+      // p->main_ahook->out_limit = nc->out_limit;
     }
 
   /* Update routes when filters changed. If the protocol in not UP,
@@ -438,6 +437,7 @@ proto_reconfigure(struct proto *p, struct proto_config *oc, struct proto_config
 	 and we have to do regular protocol restart. */
       log(L_INFO "Restarting protocol %s", p->name);
       p->disabled = 1;
+      p->down_code = PDC_CF_RESTART;
       proto_rethink_goal(p);
       p->disabled = 0;
       proto_rethink_goal(p);
@@ -512,6 +512,7 @@ protos_commit(struct config *new, struct config *old, int force_reconfig, int ty
 		log(L_INFO "Disabling protocol %s", p->name);
 
 	      PD(p, "Restarting");
+	      p->down_code = nc->disabled ? PDC_CF_DISABLE : PDC_CF_RESTART;
 	      p->cf_new = nc;
 	    }
 	  else
@@ -519,9 +520,11 @@ protos_commit(struct config *new, struct config *old, int force_reconfig, int ty
 	      if (!shutting_down)
 		log(L_INFO "Removing protocol %s", p->name);
 	      PD(p, "Unconfigured");
+	      p->down_code = PDC_CF_REMOVE;
 	      p->cf_new = NULL;
 	    }
 	  p->reconfiguring = 1;
+
 	  config_add_obstacle(old);
 	  proto_rethink_goal(p);
 	}
@@ -704,6 +707,8 @@ protos_build(void)
   proto_pool = rp_new(&root_pool, "Protocols");
   proto_flush_event = ev_new(proto_pool);
   proto_flush_event->hook = proto_flush_loop;
+  proto_shutdown_timer = tm_new(proto_pool);
+  proto_shutdown_timer->hook = proto_shutdown_loop;
 }
 
 static void
@@ -775,8 +780,13 @@ proto_schedule_feed(struct proto *p, int initial)
 
   /* Connect protocol to routing table */
   if (initial && !p->proto->multitable)
-    p->main_ahook = proto_add_announce_hook(p, p->table,
-      p->cf->in_filter, p->cf->out_filter, &p->stats);
+    {
+      p->main_ahook = proto_add_announce_hook(p, p->table, &p->stats);
+      p->main_ahook->in_filter = p->cf->in_filter;
+      p->main_ahook->out_filter = p->cf->out_filter;
+      p->main_ahook->in_limit = p->cf->in_limit;
+      // p->main_ahook->out_limit = p->cf->out_limit;
+    }
 
   proto_relink(p);
   p->attn->hook = initial ? proto_feed_initial : proto_feed_more;
@@ -861,6 +871,42 @@ proto_schedule_flush(struct proto *p)
 }
 
 
+static void
+proto_shutdown_loop(struct timer *t UNUSED)
+{
+  struct proto *p, *p_next;
+
+  WALK_LIST_DELSAFE(p, p_next, active_proto_list)
+    if (p->down_sched)
+      {
+	int restart = (p->down_sched == PDS_RESTART);
+
+	p->disabled = 1;
+	proto_rethink_goal(p);
+	if (restart)
+	  {
+	    p->disabled = 0;
+	    proto_rethink_goal(p);
+	  }
+      }
+}
+
+static inline void
+proto_schedule_down(struct proto *p, byte restart, byte code)
+{
+  /* Does not work for other states (even PS_START) */
+  ASSERT(p->proto_state == PS_UP);
+
+  /* Scheduled restart may change to shutdown, but not otherwise */
+  if (p->down_sched == PDS_DISABLE)
+    return;
+
+  p->down_sched = restart ? PDS_RESTART : PDS_DISABLE;
+  p->down_code = code;
+  tm_start_max(proto_shutdown_timer, restart ? 2 : 0);
+}
+
+
 /**
  * proto_request_feeding - request feeding routes to the protocol
  * @p: given protocol 
@@ -890,6 +936,62 @@ proto_request_feeding(struct proto *p)
   proto_schedule_feed(p, 0);
 }
 
+static const char *
+proto_limit_name(struct proto_limit *l)
+{
+  const char *actions[] = {
+    [PLA_WARN] = "warn",
+    [PLA_BLOCK] = "block",
+    [PLA_RESTART] = "restart",
+    [PLA_DISABLE] = "disable",
+  };
+
+  return actions[l->action];
+}
+
+/**
+ * proto_notify_limit: notify about limit hit and take appropriate action
+ * @ah: announce hook
+ * @l: limit being hit
+ *
+ * The function is called by the route processing core when limit @l
+ * is breached. It activates the limit and tooks appropriate action
+ * according to @l->action. It also says what should be done with the
+ * route that breached the limit.
+ *
+ * Returns 1 if the route should be freed, 0 otherwise.
+ */
+int
+proto_notify_limit(struct announce_hook *ah, struct proto_limit *l)
+{
+  struct proto *p = ah->proto;
+  int dir = (ah->in_limit == l);
+
+  if (l->active)
+    return (l->action != PLA_WARN);
+
+  l->active = 1;
+  log(L_WARN "Protocol %s hits route %s limit (%d), action: %s",
+      p->name, dir ? "import" : "export", l->limit, proto_limit_name(l));
+
+  switch (l->action)
+    {
+    case PLA_WARN:
+      return 0;
+
+    case PLA_BLOCK:
+      return 1;
+
+    case PLA_RESTART:
+    case PLA_DISABLE:
+      proto_schedule_down(p, l->action == PLA_RESTART,
+			  dir ? PDC_IN_LIMIT_HIT : PDC_OUT_LIMIT_HIT);
+      return 1;
+    }
+
+  return 0;
+}
+
 /**
  * proto_notify_state - notify core about protocol state change
  * @p: protocol the state of which has changed
@@ -919,6 +1021,8 @@ proto_notify_state(struct proto *p, unsigned ps)
   switch (ps)
     {
     case PS_DOWN:
+      p->down_code = 0;
+      p->down_sched = 0;
       if ((cs == FS_FEEDING) || (cs == FS_HAPPY))
 	proto_schedule_flush(p);
 
@@ -942,6 +1046,7 @@ proto_notify_state(struct proto *p, unsigned ps)
       proto_schedule_feed(p, 1);
       break;
     case PS_STOP:
+      p->down_sched = 0;
       if ((cs == FS_FEEDING) || (cs == FS_HAPPY))
 	proto_schedule_flush(p);
       break;
@@ -994,6 +1099,14 @@ proto_show_stats(struct proto_stats *s)
 }
 
 void
+proto_show_limit(struct proto_limit *l, const char *dsc)
+{
+  if (l)
+    cli_msg(-1006, "  %16s%d, action: %s%s", dsc, l->limit,
+	    proto_limit_name(l), l->active ? " [HIT]" : "");
+}
+
+void
 proto_show_basic_info(struct proto *p)
 {
   // cli_msg(-1006, "  Table:          %s", p->table->name);
@@ -1001,6 +1114,8 @@ proto_show_basic_info(struct proto *p)
   cli_msg(-1006, "  Input filter:   %s", filter_name(p->cf->in_filter));
   cli_msg(-1006, "  Output filter:  %s", filter_name(p->cf->out_filter));
 
+  proto_show_limit(p->cf->in_limit, "Import limit:");
+
   if (p->proto_state != PS_DOWN)
     proto_show_stats(&p->stats);
 }
@@ -1052,6 +1167,7 @@ proto_cmd_disable(struct proto *p, unsigned int arg UNUSED, int cnt UNUSED)
 
   log(L_INFO "Disabling protocol %s", p->name);
   p->disabled = 1;
+  p->down_code = PDC_CMD_DISABLE;
   proto_rethink_goal(p);
   cli_msg(-9, "%s: disabled", p->name);
 }
@@ -1082,6 +1198,7 @@ proto_cmd_restart(struct proto *p, unsigned int arg UNUSED, int cnt UNUSED)
 
   log(L_INFO "Restarting protocol %s", p->name);
   p->disabled = 1;
+  p->down_code = PDC_CMD_RESTART;
   proto_rethink_goal(p);
   p->disabled = 0;
   proto_rethink_goal(p);
@@ -1105,12 +1222,21 @@ proto_cmd_reload(struct proto *p, unsigned int dir, int cnt UNUSED)
 
   /* re-importing routes */
   if (dir != CMD_RELOAD_OUT)
-    if (! (p->reload_routes && p->reload_routes(p)))
-      {
-	cli_msg(-8006, "%s: reload failed", p->name);
-	return;
-      }
-		 
+    {
+      if (! (p->reload_routes && p->reload_routes(p)))
+	{
+	  cli_msg(-8006, "%s: reload failed", p->name);
+	  return;
+	}
+
+      /*
+       * Should be done before reload_routes() hook?
+       * Perhaps, but these hooks work asynchronously.
+       */
+      if (!p->proto->multitable && p->main_ahook->in_limit)
+	p->main_ahook->in_limit->active = 0;
+    }
+
   /* re-exporting routes */
   if (dir != CMD_RELOAD_IN)
     proto_request_feeding(p);
diff --git a/nest/protocol.h b/nest/protocol.h
index 983ce75a..3dd7cf2f 100644
--- a/nest/protocol.h
+++ b/nest/protocol.h
@@ -94,13 +94,15 @@ struct proto_config {
   u32 router_id;			/* Protocol specific router ID */
   struct rtable_config *table;		/* Table we're attached to */
   struct filter *in_filter, *out_filter; /* Attached filters */
+  struct proto_limit *in_limit;		/* Limit for importing routes from protocol */
+  // struct proto_limit *out_limit;	/* Limit for exporting routes to protocol */
 
   /* Check proto_reconfigure() and proto_copy_config() after changing struct proto_config */
 
   /* Protocol-specific data follow... */
 };
 
-  /* Protocol statistics */
+/* Protocol statistics */
 struct proto_stats {
   /* Import - from protocol to core */
   u32 imp_routes;		/* Number of routes successfully imported to the (adjacent) routing table */
@@ -138,14 +140,16 @@ struct proto {
   u32 debug;				/* Debugging flags */
   u32 mrtdump;				/* MRTDump flags */
   unsigned preference;			/* Default route preference */
-  unsigned accept_ra_types;		/* Which types of route announcements are accepted (RA_OPTIMAL or RA_ANY) */
-  unsigned disabled;			/* Manually disabled */
-  unsigned proto_state;			/* Protocol state machine (see below) */
-  unsigned core_state;			/* Core state machine (see below) */
-  unsigned core_goal;			/* State we want to reach (see below) */
-  unsigned reconfiguring;		/* We're shutting down due to reconfiguration */
-  unsigned refeeding;			/* We are refeeding (valid only if core_state == FS_FEEDING) */
-  unsigned flushing;			/* Protocol is flushed in current flush loop round */
+  byte accept_ra_types;			/* Which types of route announcements are accepted (RA_OPTIMAL or RA_ANY) */
+  byte disabled;			/* Manually disabled */
+  byte proto_state;			/* Protocol state machine (PS_*, see below) */
+  byte core_state;			/* Core state machine (FS_*, see below) */
+  byte core_goal;			/* State we want to reach (FS_*, see below) */
+  byte reconfiguring;			/* We're shutting down due to reconfiguration */
+  byte refeeding;			/* We are refeeding (valid only if core_state == FS_FEEDING) */
+  byte flushing;			/* Protocol is flushed in current flush loop round */
+  byte down_sched;			/* Shutdown is scheduled for later (PDS_*) */
+  byte down_code;			/* Reason for shutdown (PDC_* codes) */
   u32 hash_key;				/* Random key used for hashing of neighbors */
   bird_clock_t last_state_change;	/* Time of last state transition */
   char *last_state_name_announced;	/* Last state name we've announced to the user */
@@ -210,6 +214,18 @@ struct proto_spec {
 };
 
 
+#define PDS_DISABLE		1	/* Proto disable scheduled */
+#define PDS_RESTART		2	/* Proto restart scheduled */
+
+#define PDC_CF_REMOVE		0x01	/* Removed in new config */
+#define PDC_CF_DISABLE		0x02	/* Disabled in new config */
+#define PDC_CF_RESTART		0x03	/* Restart due to reconfiguration */
+#define PDC_CMD_DISABLE		0x11	/* Result of disable command */
+#define PDC_CMD_RESTART		0x12	/* Result of restart command */
+#define PDC_IN_LIMIT_HIT	0x21	/* Route import limit reached */
+#define PDC_OUT_LIMIT_HIT	0x22	/* Route export limit reached - not implemented */
+
+
 void *proto_new(struct proto_config *, unsigned size);
 void *proto_config_new(struct protocol *, unsigned size, int class);
 void proto_copy_config(struct proto_config *dest, struct proto_config *src);
@@ -220,6 +236,7 @@ proto_copy_rest(struct proto_config *dest, struct proto_config *src, unsigned si
 { memcpy(dest + 1, src + 1, size - sizeof(struct proto_config)); }
 
 
+void proto_show_limit(struct proto_limit *l, const char *dsc);
 void proto_show_basic_info(struct proto *p);
 
 void proto_cmd_show(struct proto *, unsigned int, int);
@@ -348,6 +365,24 @@ void proto_notify_state(struct proto *p, unsigned state);
 
 extern struct proto_config *cf_dev_proto;
 
+
+/*
+ * Protocol limits
+ */
+
+#define PLA_WARN	1	/* Issue log warning */
+#define PLA_BLOCK	2	/* Block new routes */
+#define PLA_RESTART	4	/* Force protocol restart */
+#define PLA_DISABLE	5	/* Shutdown and disable protocol */
+
+struct proto_limit {
+  u32 limit;			/* Maximum number of prefixes */
+  byte action;			/* Action to take (PLA_*) */
+  byte active;			/* Limit is active */
+};
+
+int proto_notify_limit(struct announce_hook *ah, struct proto_limit *l);
+ 
 /*
  *	Route Announcement Hook
  */
@@ -358,11 +393,13 @@ struct announce_hook {
   struct proto *proto;
   struct filter *in_filter;		/* Input filter */
   struct filter *out_filter;		/* Output filter */
+  struct proto_limit *in_limit;		/* Input limit */
+  // struct proto_limit *out_limit;	/* Output limit */
   struct proto_stats *stats;		/* Per-table protocol statistics */
   struct announce_hook *next;		/* Next hook for the same protocol */
 };
 
-struct announce_hook *proto_add_announce_hook(struct proto *, struct rtable *, struct filter *, struct filter *, struct proto_stats *);
+struct announce_hook *proto_add_announce_hook(struct proto *p, struct rtable *t, struct proto_stats *stats);
 struct announce_hook *proto_find_announce_hook(struct proto *p, struct rtable *t);
 
 #endif
diff --git a/nest/rt-table.c b/nest/rt-table.c
index 310c1afd..6a28fd43 100644
--- a/nest/rt-table.c
+++ b/nest/rt-table.c
@@ -182,6 +182,16 @@ rte_trace_out(unsigned int flag, struct proto *p, rte *e, char *msg)
     rte_trace(p, e, '<', msg);
 }
 
+/**
+ * do_rte_announce - announce new rte to protocol
+ * @ah: pointer to announce hook
+ * @type: announce type (RA_ANY or RA_OPTIMAL)
+ * @net: pointer to announced network
+ * @new: new rte or NULL
+ * @old: previous rte or NULL
+ * @tmpa: new rte attributes (possibly modified by filter)
+ * @refeed: whether we are refeeding protocol
+ */
 static inline void
 do_rte_announce(struct announce_hook *ah, int type UNUSED, net *net, rte *new, rte *old, ea_list *tmpa, int refeed)
 {
@@ -474,6 +484,15 @@ rte_recalculate(struct announce_hook *ah, net *net, rte *new, ea_list *tmpa, str
       return;
     }
 
+  struct proto_limit *l = ah->in_limit;
+  if (l && !old && new && (stats->imp_routes >= l->limit) && proto_notify_limit(ah, l))
+    {
+      stats->imp_updates_ignored++;
+      rte_trace_in(D_FILTERS, p, new, "ignored [limit]");
+      rte_free_quick(new);
+      return;
+    }
+
   if (new)
     stats->imp_updates_accepted++;
   else