director: Add old host's up/down and vhost count parameters to direct…

…or_flush_socket

The "down" status allows the script to determine whether it should try to
perform any work on the old host. The vhost count may be unnecessary, but
might be useful for some purpose.

src/director/director.c

@@ -808,6 +808,8 @@ director_flush_user(struct director *dir, struct user *user)
 		t_strdup_printf("%u", user->username_hash),
 		net_ip2addr(&ctx->old_host_ip),
 		net_ip2addr(&user->host->ip),
+		ctx->old_host_down ? "down" : "up",
+		dec2str(ctx->old_host_vhost_count),
 		NULL
 	};
 
@@ -1008,8 +1010,11 @@ director_kill_user(struct director *dir, struct director_host *src,
 	ctx->tag = tag;
 	ctx->username_hash = user->username_hash;
 	ctx->kill_is_self_initiated = src->self;
-	if (old_host != NULL)
+	if (old_host != NULL) {
 		ctx->old_host_ip = old_host->ip;
+		ctx->old_host_down = old_host->down;
+		ctx->old_host_vhost_count = old_host->vhost_count;
+	}
 
 	dir->users_moving_count++;
 	ctx->to_move = timeout_add(DIRECTOR_USER_MOVE_TIMEOUT_MSECS,

src/director/director.h

@@ -76,6 +76,8 @@ struct director_kill_context {
 	struct mail_tag *tag;
 	unsigned int username_hash;
 	struct ip_addr old_host_ip;
+	unsigned int old_host_vhost_count;
+	bool old_host_down;
 	bool kill_is_self_initiated;
 	bool callback_pending;