subd: Add a helper to get the current owning subd for a given peer

This is currently in opening_control since that's the only part that has
access to the uncommitted_channel internals. Otherwise it's independent from
the specific daemon.

lightningd/opening_control.c

@@ -29,7 +29,6 @@
 #include <lightningd/notification.h>
 #include <lightningd/opening_control.h>
 #include <lightningd/options.h>
-#include <lightningd/peer_control.h>
 #include <lightningd/plugin_hook.h>
 #include <lightningd/subd.h>
 #include <openingd/gen_opening_wire.h>
@@ -1338,3 +1337,16 @@ void opening_dev_memleak(struct command *cmd)
 	opening_memleak_req_next(cmd, NULL);
 }
 #endif /* DEVELOPER */
+
+struct subd *peer_get_owning_subd(struct peer *peer)
+{
+	struct channel *channel;
+	channel = peer_active_channel(peer);
+
+	if (channel != NULL) {
+		return channel->owner;
+	} else if (peer->uncommitted_channel != NULL) {
+		return peer->uncommitted_channel->openingd;
+	}
+	return NULL;
+}

lightningd/opening_control.h

@@ -2,6 +2,7 @@
 #define LIGHTNING_LIGHTNINGD_OPENING_CONTROL_H
 #include "config.h"
 #include <ccan/short_types/short_types.h>
+#include <lightningd/peer_control.h>
 
 struct channel_id;
 struct crypto_state;
@@ -26,4 +27,6 @@ struct command;
 void opening_dev_memleak(struct command *cmd);
 #endif
 
+struct subd *peer_get_owning_subd(struct peer *peer);
+
 #endif /* LIGHTNING_LIGHTNINGD_OPENING_CONTROL_H */