BGP: Shutdown communication (RFC 8203)

The patch implements BGP Administrative Shutdown Communication (RFC 8203)
allowing BGP operators to pass messages related to BGP session
administrative shutdown/restart. It handles both transmit and receive of
shutdown messages. Messages are logged and may be displayed by show
protocol all command.

Thanks to Job Snijders for the basic patch.

3 files changed, 68 insertions, 25 deletions

diff --git a/nest/config.Y b/nest/config.Y
index 025e8969..f51be6ea 100644
--- a/nest/config.Y
+++ b/nest/config.Y
@@ -696,12 +696,12 @@ echo_size:
    }
  ;
 
-CF_CLI(DISABLE, proto_patt, <protocol> | \"<pattern>\" | all, [[Disable protocol]])
-{ proto_apply_cmd($2, proto_cmd_disable, 1, 0); } ;
-CF_CLI(ENABLE, proto_patt, <protocol> | \"<pattern>\" | all, [[Enable protocol]])
-{ proto_apply_cmd($2, proto_cmd_enable, 1, 0); } ;
-CF_CLI(RESTART, proto_patt, <protocol> | \"<pattern>\" | all, [[Restart protocol]])
-{ proto_apply_cmd($2, proto_cmd_restart, 1, 0); } ;
+CF_CLI(DISABLE, proto_patt text_or_none, (<protocol> | \"<pattern>\" | all) [message], [[Disable protocol]])
+{ proto_apply_cmd($2, proto_cmd_disable, 1, (uintptr_t) $3); } ;
+CF_CLI(ENABLE, proto_patt text_or_none, (<protocol> | \"<pattern>\" | all) [message], [[Enable protocol]])
+{ proto_apply_cmd($2, proto_cmd_enable, 1, (uintptr_t) $3); } ;
+CF_CLI(RESTART, proto_patt text_or_none, (<protocol> | \"<pattern>\" | all) [message], [[Restart protocol]])
+{ proto_apply_cmd($2, proto_cmd_restart, 1, (uintptr_t) $3); } ;
 CF_CLI(RELOAD, proto_patt, <protocol> | \"<pattern>\" | all, [[Reload protocol]])
 { proto_apply_cmd($2, proto_cmd_reload, 1, CMD_RELOAD); } ;
 CF_CLI(RELOAD IN, proto_patt, <protocol> | \"<pattern>\" | all, [[Reload protocol (just imported routes)]])
diff --git a/nest/proto.c b/nest/proto.c
index 64422ee3..552d53ae 100644
--- a/nest/proto.c
+++ b/nest/proto.c
@@ -610,6 +610,7 @@ proto_rethink_goal(struct proto *p)
       config_del_obstacle(p->cf->global);
       rem_node(&p->n);
       rem_node(&p->glob_node);
+      mb_free(p->message);
       mb_free(p);
       if (!nc)
 	return;
@@ -1096,6 +1097,39 @@ proto_schedule_down(struct proto *p, byte restart, byte code)
   tm_start_max(proto_shutdown_timer, restart ? 2 : 0);
 }
 
+/**
+ * proto_set_message - set administrative message to protocol
+ * @p: protocol
+ * @msg: message
+ * @len: message length (-1 for NULL-terminated string)
+ *
+ * The function sets administrative message (string) related to protocol state
+ * change. It is called by the nest code for manual enable/disable/restart
+ * commands all routes to the protocol, and by protocol-specific code when the
+ * protocol state change is initiated by the protocol. Using NULL message clears
+ * the last message. The message string may be either NULL-terminated or with an
+ * explicit length.
+ */
+void
+proto_set_message(struct proto *p, char *msg, int len)
+{
+  mb_free(p->message);
+  p->message = NULL;
+
+  if (!msg || !len)
+    return;
+
+  if (len < 0)
+    len = strlen(msg);
+
+  if (!len)
+    return;
+
+  p->message = mb_alloc(proto_pool, len + 1);
+  memcpy(p->message, msg, len);
+  p->message[len] = 0;
+}
+
 
 /**
  * proto_request_feeding - request feeding routes to the protocol
@@ -1497,7 +1531,7 @@ proto_show_basic_info(struct proto *p)
 }
 
 void
-proto_cmd_show(struct proto *p, uint verbose, int cnt)
+proto_cmd_show(struct proto *p, uintptr_t verbose, int cnt)
 {
   byte buf[256], tbuf[TM_DATETIME_BUFFER_SIZE];
 
@@ -1520,6 +1554,10 @@ proto_cmd_show(struct proto *p, uint verbose, int cnt)
     {
       if (p->cf->dsc)
 	cli_msg(-1006, "  Description:    %s", p->cf->dsc);
+
+      if (p->message)
+	cli_msg(-1006, "  Message:        %s", p->message);
+
       if (p->cf->router_id)
 	cli_msg(-1006, "  Router ID:      %R", p->cf->router_id);
 
@@ -1533,7 +1571,7 @@ proto_cmd_show(struct proto *p, uint verbose, int cnt)
 }
 
 void
-proto_cmd_disable(struct proto *p, uint arg UNUSED, int cnt UNUSED)
+proto_cmd_disable(struct proto *p, uintptr_t arg, int cnt UNUSED)
 {
   if (p->disabled)
     {
@@ -1544,12 +1582,13 @@ proto_cmd_disable(struct proto *p, uint arg UNUSED, int cnt UNUSED)
   log(L_INFO "Disabling protocol %s", p->name);
   p->disabled = 1;
   p->down_code = PDC_CMD_DISABLE;
+  proto_set_message(p, (char *) arg, -1);
   proto_rethink_goal(p);
   cli_msg(-9, "%s: disabled", p->name);
 }
 
 void
-proto_cmd_enable(struct proto *p, uint arg UNUSED, int cnt UNUSED)
+proto_cmd_enable(struct proto *p, uintptr_t arg, int cnt UNUSED)
 {
   if (!p->disabled)
     {
@@ -1559,12 +1598,13 @@ proto_cmd_enable(struct proto *p, uint arg UNUSED, int cnt UNUSED)
 
   log(L_INFO "Enabling protocol %s", p->name);
   p->disabled = 0;
+  proto_set_message(p, (char *) arg, -1);
   proto_rethink_goal(p);
   cli_msg(-11, "%s: enabled", p->name);
 }
 
 void
-proto_cmd_restart(struct proto *p, uint arg UNUSED, int cnt UNUSED)
+proto_cmd_restart(struct proto *p, uintptr_t arg, int cnt UNUSED)
 {
   if (p->disabled)
     {
@@ -1575,6 +1615,7 @@ proto_cmd_restart(struct proto *p, uint arg UNUSED, int cnt UNUSED)
   log(L_INFO "Restarting protocol %s", p->name);
   p->disabled = 1;
   p->down_code = PDC_CMD_RESTART;
+  proto_set_message(p, (char *) arg, -1);
   proto_rethink_goal(p);
   p->disabled = 0;
   proto_rethink_goal(p);
@@ -1582,7 +1623,7 @@ proto_cmd_restart(struct proto *p, uint arg UNUSED, int cnt UNUSED)
 }
 
 void
-proto_cmd_reload(struct proto *p, uint dir, int cnt UNUSED)
+proto_cmd_reload(struct proto *p, uintptr_t dir, int cnt UNUSED)
 {
   if (p->disabled)
     {
@@ -1624,19 +1665,19 @@ proto_cmd_reload(struct proto *p, uint dir, int cnt UNUSED)
 }
 
 void
-proto_cmd_debug(struct proto *p, uint mask, int cnt UNUSED)
+proto_cmd_debug(struct proto *p, uintptr_t mask, int cnt UNUSED)
 {
   p->debug = mask;
 }
 
 void
-proto_cmd_mrtdump(struct proto *p, uint mask, int cnt UNUSED)
+proto_cmd_mrtdump(struct proto *p, uintptr_t mask, int cnt UNUSED)
 {
   p->mrtdump = mask;
 }
 
 static void
-proto_apply_cmd_symbol(struct symbol *s, void (* cmd)(struct proto *, uint, int), uint arg)
+proto_apply_cmd_symbol(struct symbol *s, void (* cmd)(struct proto *, uintptr_t, int), uintptr_t arg)
 {
   if (s->class != SYM_PROTO)
     {
@@ -1649,7 +1690,7 @@ proto_apply_cmd_symbol(struct symbol *s, void (* cmd)(struct proto *, uint, int)
 }
 
 static void
-proto_apply_cmd_patt(char *patt, void (* cmd)(struct proto *, uint, int), uint arg)
+proto_apply_cmd_patt(char *patt, void (* cmd)(struct proto *, uintptr_t, int), uintptr_t arg)
 {
   int cnt = 0;
 
@@ -1669,8 +1710,8 @@ proto_apply_cmd_patt(char *patt, void (* cmd)(struct proto *, uint, int), uint a
 }
 
 void
-proto_apply_cmd(struct proto_spec ps, void (* cmd)(struct proto *, uint, int),
-		int restricted, uint arg)
+proto_apply_cmd(struct proto_spec ps, void (* cmd)(struct proto *, uintptr_t, int),
+		int restricted, uintptr_t arg)
 {
   if (restricted && cli_access_restricted())
     return;
diff --git a/nest/protocol.h b/nest/protocol.h
index 18dfbd6f..5aca9a4e 100644
--- a/nest/protocol.h
+++ b/nest/protocol.h
@@ -164,6 +164,7 @@ struct proto {
   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 */
+  char *message;			/* State-change message, allocated from proto_pool */
   struct proto_stats stats;		/* Current protocol statistics */
 
   /*
@@ -250,6 +251,7 @@ struct proto_spec {
 void *proto_new(struct proto_config *, unsigned size);
 void *proto_config_new(struct protocol *, int class);
 void proto_copy_config(struct proto_config *dest, struct proto_config *src);
+void proto_set_message(struct proto *p, char *msg, int len);
 void proto_request_feeding(struct proto *p);
 
 static inline void
@@ -267,15 +269,15 @@ void proto_graceful_restart_unlock(struct proto *p);
 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 *, uint, int);
-void proto_cmd_disable(struct proto *, uint, int);
-void proto_cmd_enable(struct proto *, uint, int);
-void proto_cmd_restart(struct proto *, uint, int);
-void proto_cmd_reload(struct proto *, uint, int);
-void proto_cmd_debug(struct proto *, uint, int);
-void proto_cmd_mrtdump(struct proto *, uint, int);
+void proto_cmd_show(struct proto *, uintptr_t, int);
+void proto_cmd_disable(struct proto *, uintptr_t, int);
+void proto_cmd_enable(struct proto *, uintptr_t, int);
+void proto_cmd_restart(struct proto *, uintptr_t, int);
+void proto_cmd_reload(struct proto *, uintptr_t, int);
+void proto_cmd_debug(struct proto *, uintptr_t, int);
+void proto_cmd_mrtdump(struct proto *, uintptr_t, int);
 
-void proto_apply_cmd(struct proto_spec ps, void (* cmd)(struct proto *, uint, int), int restricted, uint arg);
+void proto_apply_cmd(struct proto_spec ps, void (* cmd)(struct proto *, uintptr_t, int), int restricted, uintptr_t arg);
 struct proto *proto_get_named(struct symbol *, struct protocol *);
 
 #define CMD_RELOAD	0