relayd: expose backup role of relay tables to relayctl

Since I haven't received an OK for my manpage diff yet, and the
situation with the backup tables is extremely unclear, here's a first
step.

I would like to make it transparent for users what is marked as backup
table. Here is an example with a modified relayctl call:

doas relayctl -v show summary
Id   Type   Name                     Avlblty Checks   Status
1    relay  https-gateway                             active
1    table  wiki:3000                                 active (1 hosts)
1    host   10.0.23.6                100.00% 1/1      up
2    table  ap:6443                                   backup active (1 hosts)
2    host   10.0.23.6                100.00% 1/1      up

OK?

commit 18b5909ffabbe72603ac927c0550ada83b2cc817
Author: Rafael Sadowski <[email protected]>
Date:   Sat Aug 1 21:14:53 2026 +0200

    relayd: expose backup role of relay tables to relayctl
    
    F_BACKUP lives on the relay_table binding (rlt_flags), not on the table itself,
    because one table can be primary for one relay and backup for another. As a
    result IMSG_CTL_TABLE from pfe never carried the backup role, and relayctl
    always displayed backup tables as plain active.
    
    Send a copy of the table when reporting status and mark it as backup if the
    binding says so. The shared table stays untouched and all other flags are
    preserved.

diff --git a/pfe.c b/pfe.c
index 1438171..5b89fa9 100644
--- a/pfe.c
+++ b/pfe.c
@@ -409,8 +409,13 @@ relays:
 		    &rlay->rl_stats, sizeof(rlay->rl_stats));
 
 		TAILQ_FOREACH(rlt, &rlay->rl_tables, rlt_entry) {
+			struct table	 tbl = *rlt->rlt_table;
+
+			/* Backup role lives on rlt_flags; expose it. */
+			if (rlt->rlt_flags & F_BACKUP)
+				tbl.conf.flags |= F_BACKUP;
 			imsg_compose_event(&c->iev, IMSG_CTL_TABLE, 0, 0, -1,
-			    rlt->rlt_table, sizeof(*rlt->rlt_table));
+			    &tbl, sizeof(tbl));
 			if (!(rlt->rlt_table->conf.flags & F_DISABLE))
 				TAILQ_FOREACH(host,
 				    &rlt->rlt_table->hosts, entry)