channeld: send optional init message.

We use this to make it send the funding_signed message, rather than having
the master daemon do it (which was even more hacky).  It also means it
can handle the crypto, so no need for the packet to be handed up encrypted,
and also make --dev-disconnect "just work" for this packet.

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

lightningd/channel/channel.c

@@ -1027,8 +1027,9 @@ static void init_channel(struct peer *peer, const u8 *msg)
 	struct pubkey funding_pubkey[NUM_SIDES];
 	struct sha256_double funding_txid;
 	bool am_funder;
+	u8 *funding_signed;
 
-	if (!fromwire_channel_init(msg, NULL,
+	if (!fromwire_channel_init(msg, msg, NULL,
 				   &funding_txid, &funding_txout,
 				   &peer->conf[LOCAL], &peer->conf[REMOTE],
 				   &peer->their_commit_sig,
@@ -1046,7 +1047,8 @@ static void init_channel(struct peer *peer, const u8 *msg)
 				   &peer->node_ids[LOCAL],
 				   &peer->node_ids[REMOTE],
 				   &peer->commit_msec,
-				   &peer->cltv_delta))
+				   &peer->cltv_delta,
+				   &funding_signed))
 		status_failed(WIRE_CHANNEL_BAD_COMMAND, "Init: %s",
 			      tal_hex(msg, msg));
 
@@ -1076,6 +1078,10 @@ static void init_channel(struct peer *peer, const u8 *msg)
 	/* OK, now we can process peer messages. */
 	peer->peer_conn = io_new_conn(peer, PEER_FD, setup_peer_conn, peer);
 	io_set_finish(peer->peer_conn, peer_conn_broken, peer);
+
+	/* If we have a funding_signed message, we send that immediately */
+	if (tal_len(funding_signed) != 0)
+		msg_enqueue(&peer->peer_out, take(funding_signed));
 }
 
 static void handle_funding_locked(struct peer *peer, const u8 *msg)

lightningd/channel/channel_wire.csv

@@ -40,6 +40,8 @@ channel_init,533,local_node_id,struct pubkey
 channel_init,566,remote_node_id,struct pubkey
 channel_init,599,commit_msec,4
 channel_init,603,cltv_delta,u16
+channel_init,605,init_peer_pkt_len,u16
+channel_init,607,init_peer_pkt,init_peer_pkt_len*u8
 
 # Tx is deep enough, go!
 channel_funding_locked,2

lightningd/opening/opening.c

@@ -465,7 +465,7 @@ static u8 *fundee_channel(struct state *state,
 	secp256k1_ecdsa_signature theirsig, sig;
 	struct bitcoin_tx **txs;
 	struct sha256_double chain_hash;
-	u8 *msg, *encmsg;
+	u8 *msg;
 	const u8 **wscripts;
 
 	state->remoteconf = tal(state, struct channel_config);
@@ -648,10 +648,9 @@ static u8 *fundee_channel(struct state *state,
 		      &state->our_secrets.funding_privkey,
 		      our_funding_pubkey, &sig);
 
-	/* We don't send this ourselves: master does, because it needs to save
-	 * state to disk before doing so. */
+	/* We don't send this ourselves: channeld does, because master needs
+	 * to save state to disk before doing so. */
 	msg = towire_funding_signed(state, &channel_id, &sig);
-	encmsg = cryptomsg_encrypt_msg(state, &state->cs, msg);
 
 	return towire_opening_fundee_reply(state,
 					   state->remoteconf,
@@ -666,7 +665,7 @@ static u8 *fundee_channel(struct state *state,
 					   state->funding_txout,
 					   state->funding_satoshis,
 					   state->push_msat,
-					   encmsg);
+					   msg);
 }
 
 #ifndef TESTING

lightningd/peer_control.c

@@ -721,7 +721,8 @@ static enum watch_result funding_lockin_cb(struct peer *peer,
 }
 
 /* FIXME: Reshuffle. */
-static void peer_start_channeld(struct peer *peer, enum peer_state oldstate);
+static void peer_start_channeld(struct peer *peer, enum peer_state oldstate,
+				const u8 *funding_signed);
 
 static bool opening_got_hsm_funding_sig(struct subd *hsm, const u8 *resp,
 					const int *fds,
@@ -764,7 +765,7 @@ static bool opening_got_hsm_funding_sig(struct subd *hsm, const u8 *resp,
 	command_success(fc->cmd, null_response(fc->cmd));
 
 	/* Start normal channel daemon. */
-	peer_start_channeld(fc->peer, GETTING_SIG_FROM_HSM);
+	peer_start_channeld(fc->peer, GETTING_SIG_FROM_HSM, NULL);
 
 	tal_free(fc);
 	return true;
@@ -1542,7 +1543,11 @@ static bool peer_start_channeld_hsmfd(struct subd *hsm, const u8 *resp,
 				      &peer->ld->dstate.id,
 				      peer->id,
 				      time_to_msec(cfg->commit_time),
-				      cfg->deadline_blocks);
+				      cfg->deadline_blocks,
+				      peer->funding_signed);
+
+	/* Don't need this any more (we never re-transmit it) */
+	peer->funding_signed = tal_free(peer->funding_signed);
 
 	/* We don't expect a response: we are triggered by funding_depth_cb. */
 	subd_send_msg(peer->owner, take(initmsg));
@@ -1553,7 +1558,8 @@ static bool peer_start_channeld_hsmfd(struct subd *hsm, const u8 *resp,
 }
 
 /* opening is done, start lightningd_channel for peer. */
-static void peer_start_channeld(struct peer *peer, enum peer_state oldstate)
+static void peer_start_channeld(struct peer *peer, enum peer_state oldstate,
+				const u8 *funding_signed)
 {
 	/* Unowned: back to being owned by main daemon. */
 	peer->owner = NULL;
@@ -1568,6 +1574,9 @@ static void peer_start_channeld(struct peer *peer, enum peer_state oldstate)
 
 	peer_set_condition(peer, oldstate, GETTING_HSMFD);
 
+	/* Save this for when we get HSM fd. */
+	peer->funding_signed = funding_signed;
+
 	/* Get fd from hsm. */
 	subd_req(peer, peer->ld->hsm,
 		 take(towire_hsmctl_hsmfd_channeld(peer, peer->unique_id)),
@@ -1665,7 +1674,7 @@ static bool opening_fundee_finished(struct subd *opening,
 					   const int *fds,
 					   struct peer *peer)
 {
-	u8 *funding_msg_enc;
+	u8 *funding_signed;
 	struct channel_info *channel_info;
 
 	log_debug(peer->log, "Got opening_fundee_finish_response");
@@ -1677,7 +1686,7 @@ static bool opening_fundee_finished(struct subd *opening,
 	peer->channel_info = channel_info = tal(peer, struct channel_info);
 
 	peer->funding_txid = tal(peer, struct sha256_double);
-	if (!fromwire_opening_fundee_reply(reply, reply, NULL,
+	if (!fromwire_opening_fundee_reply(peer, reply, NULL,
 					   &channel_info->their_config,
 					   &channel_info->commit_sig,
 					   peer->cs,
@@ -1690,7 +1699,7 @@ static bool opening_fundee_finished(struct subd *opening,
 					   &peer->funding_outnum,
 					   &peer->funding_satoshi,
 					   &peer->push_msat,
-					   &funding_msg_enc)) {
+					   &funding_signed)) {
 		log_broken(peer->log, "bad OPENING_FUNDEE_REPLY %s",
 			   tal_hex(reply, reply));
 		return false;
@@ -1702,16 +1711,9 @@ static bool opening_fundee_finished(struct subd *opening,
 	watch_txid(peer, peer->ld->topology, peer, peer->funding_txid,
 		   funding_lockin_cb, NULL);
 
-	/* FIXME: Remove synchronous write! */
-	if (write(peer->fd, funding_msg_enc, tal_len(funding_msg_enc))
-	    != tal_len(funding_msg_enc)) {
-		log_broken(peer->log, "Could not write funding_signed msg");
-		return false;
-	}
-
 	/* On to normal operation! */
 	peer->owner = NULL;
-	peer_start_channeld(peer, OPENINGD);
+	peer_start_channeld(peer, OPENINGD, funding_signed);
 
 	/* Tell opening daemon to exit. */
 	return false;

lightningd/peer_control.h

@@ -51,6 +51,9 @@ struct peer {
 	/* Our channel config. */
 	struct channel_config our_config;
 
+	/* funding_signed packet for fundee, waiting to send. */
+	const u8 *funding_signed;
+
 	/* Channel if locked. */
 	struct short_channel_id *scid;