lightningd/lightningd: create unique ID for each peer.

This distinguishes them before they have an ID, and also if the daemon
doesn't know the ID.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

lightningd/peer_control.c

@@ -19,6 +19,9 @@
 struct peer {
 	struct lightningd *ld;
 
+	/* Unique ID (works before we know their pubkey) */
+	u64 unique_id;
+
 	/* Inside ld->peers. */
 	struct list_node list;
 
@@ -44,8 +47,10 @@ static void destroy_peer(struct peer *peer)
 
 static struct peer *new_peer(const tal_t *ctx, struct lightningd *ld, int fd)
 {
+	static u64 id_counter;
 	struct peer *peer = tal(ctx, struct peer);
 	peer->ld = ld;
+	peer->unique_id = id_counter++;
 	peer->owner = NULL;
 	peer->id = NULL;
 	peer->fd = fd;
@@ -54,6 +59,16 @@ static struct peer *new_peer(const tal_t *ctx, struct lightningd *ld, int fd)
 	return peer;
 }
 
+struct peer *peer_by_unique_id(struct lightningd *ld, u64 unique_id)
+{
+	struct peer *p;
+
+	list_for_each(&ld->peers, p, list)
+		if (p->unique_id == unique_id)
+			return p;
+	return NULL;
+}
+
 static void handshake_succeeded(struct subdaemon *hs, const u8 *msg,
 				struct peer *peer)
 {
@@ -145,8 +160,8 @@ static struct io_plan *peer_in(struct io_conn *conn, struct lightningd *ld)
 	struct peer *peer = new_peer(ld, ld, io_conn_fd(conn));
 
 	/* Get HSM fd for this peer. */
-	/* FIXME: We use pointer as ID. */
+	subdaemon_req(ld->hsm,
-	subdaemon_req(ld->hsm, take(towire_hsmctl_hsmfd_ecdh(ld, (u64)peer)),
+		      take(towire_hsmctl_hsmfd_ecdh(ld, peer->unique_id)),
 		      -1, &peer->hsmfd, peer_got_hsmfd, peer);
 
 	/* We don't need conn, we'll pass fd to handshaked. */
@@ -273,8 +288,8 @@ static struct io_plan *peer_out(struct io_conn *conn,
 	peer->id = tal_dup(peer, struct pubkey, &jc->id);
 
 	/* Get HSM fd for this peer. */
-	/* FIXME: We use pointer as ID. */
+	subdaemon_req(ld->hsm,
-	subdaemon_req(ld->hsm, take(towire_hsmctl_hsmfd_ecdh(ld, (u64)peer)),
+		      take(towire_hsmctl_hsmfd_ecdh(ld, peer->unique_id)),
 		      -1, &peer->hsmfd, peer_got_hsmfd, peer);
 
 	/* We don't need conn, we'll pass fd to handshaked. */

lightningd/peer_control.h

@@ -5,5 +5,7 @@
 
 struct lightningd;
 
+struct peer *peer_by_unique_id(struct lightningd *ld, u64 unique_id);
+
 void setup_listeners(struct lightningd *ld);
 #endif /* LIGHTNING_LIGHTNINGD_PEER_CONTROL_H */