bgpd: fix crash when re-adding a rpki server

Fix a crash when re-adding a rpki server:

> r2# sh run bgpd
> [...]
> rpki
>  rpki retry_interval 5
>  rpki cache 192.0.2.1 15432 preference 1
> exit
> [...]
> r2# conf t
> r2(config)# rpki
> r2(config-rpki)# no rpki cache 192.0.2.1 15432 preference 1
> r2(config-rpki)# do show rpki cache-connection
> Cannot find a connected group.
> r2(config-rpki)# rpki cache 192.0.2.1 15432 preference 1
> r2(config-rpki)# do show rpki cache-connection
> vtysh: error reading from bgpd: Resource temporarily unavailable (11)Warning: closing connection to bgpd because of an I/O error!

> #0  raise (sig=<optimized out>) at ../sysdeps/unix/sysv/linux/raise.c:50
> #1  0x00007f3fd2d16e57 in core_handler (signo=11, siginfo=0x7ffffd5931b0, context=0x7ffffd593080) at lib/sigevent.c:246
> #2  <signal handler called>
> #3  0x00007f3fd26926b4 in tommy_list_head (list=0x2e322e302e323931) at /home/lscalber/git/rtrlib/./third-party/tommyds/tommylist.h:125
> #4  0x00007f3fd2693812 in rtr_mgr_get_first_group (config=0x55fbf31d7f00) at /home/lscalber/git/rtrlib/rtrlib/rtr_mgr.c:409
> #5  0x00007f3fd2ebef59 in get_connected_group () at bgpd/bgp_rpki.c:718
> #6  0x00007f3fd2ec0b39 in show_rpki_cache_connection_magic (self=0x7f3fd2ec69c0 <show_rpki_cache_connection_cmd>, vty=0x55fbf31f9ef0, argc=3, argv=0x55fbf31f99d0, uj=0x0)
> #   at bgpd/bgp_rpki.c:1575
> #7  0x00007f3fd2ebd4da in show_rpki_cache_connection (self=0x7f3fd2ec69c0 <show_rpki_cache_connection_cmd>, vty=0x55fbf31f9ef0, argc=3, argv=0x55fbf31f99d0) at ./bgpd/bgp_rpki_clippy.c:648
> #8  0x00007f3fd2c8a142 in cmd_execute_command_real (vline=0x55fbf31f9990, vty=0x55fbf31f9ef0, cmd=0x0, up_level=0) at lib/command.c:978
> #9  0x00007f3fd2c8a25c in cmd_execute_command (vline=0x55fbf31e5260, vty=0x55fbf31f9ef0, cmd=0x0, vtysh=0) at lib/command.c:1028
> FRRouting#10 0x00007f3fd2c8a7f1 in cmd_execute (vty=0x55fbf31f9ef0, cmd=0x55fbf3200680 "do show rpki cache-connection ", matched=0x0, vtysh=0) at lib/command.c:1203
> FRRouting#11 0x00007f3fd2d36548 in vty_command (vty=0x55fbf31f9ef0, buf=0x55fbf3200680 "do show rpki cache-connection ") at lib/vty.c:594
> FRRouting#12 0x00007f3fd2d382e1 in vty_execute (vty=0x55fbf31f9ef0) at lib/vty.c:1357
> FRRouting#13 0x00007f3fd2d3a519 in vtysh_read (thread=0x7ffffd5963c0) at lib/vty.c:2365
> FRRouting#14 0x00007f3fd2d2faf6 in event_call (thread=0x7ffffd5963c0) at lib/event.c:1974
> FRRouting#15 0x00007f3fd2cc238e in frr_run (master=0x55fbf2a0cd60) at lib/libfrr.c:1214
> FRRouting#16 0x000055fbf073de40 in main (argc=9, argv=0x7ffffd596618) at bgpd/bgp_main.c:510

Signed-off-by: Louis Scalbert <louis.scalbert@6wind.com>

bgpd/bgp_rpki.c

@@ -1249,6 +1249,7 @@ DEFPY(rpki_cache, rpki_cache_cmd,
 	int return_value;
 	struct listnode *cache_node;
 	struct cache *current_cache;
+	bool init = !!list_isempty(cache_list);
 
 	for (ALL_LIST_ELEMENTS_RO(cache_list, cache_node, current_cache)) {
 		if (current_cache->preference == preference) {
@@ -1281,6 +1282,9 @@ DEFPY(rpki_cache, rpki_cache_cmd,
 		return CMD_WARNING;
 	}
 
+	if (init)
+		start();
+
 	return CMD_SUCCESS;
 }