channeld: tell master about next_per_commit_point.

It needs to save them to the db in case of restart; this means we tell
it about funding_locked, as well as the next_per_commit_point given
in revoke_and_ack.

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

lightningd/channel/channel.c

@@ -286,6 +286,9 @@ static struct io_plan *handle_peer_funding_locked(struct io_conn *conn,
 			      "Funding locked twice");
 
 	peer->funding_locked[REMOTE] = true;
+	daemon_conn_send(&peer->master,
+			 take(towire_channel_got_funding_locked(peer,
+					&peer->current_per_commit[REMOTE])));
 
 	if (peer->funding_locked[LOCAL]) {
 		daemon_conn_send(&peer->master,
@@ -807,6 +810,7 @@ static struct io_plan *handle_peer_commit_sig(struct io_conn *conn,
 
 static u8 *got_revoke_msg(const tal_t *ctx, u64 revoke_num,
 			  const struct sha256 *per_commitment_secret,
+			  const struct pubkey *next_per_commit_point,
 			  const struct htlc **changed_htlcs)
 {
 	tal_t *tmpctx = tal_tmpctx(ctx);
@@ -826,7 +830,7 @@ static u8 *got_revoke_msg(const tal_t *ctx, u64 revoke_num,
 	}
 
 	msg = towire_channel_got_revoke(ctx, revoke_num, per_commitment_secret,
-					changed);
+					next_per_commit_point, changed);
 	tal_free(tmpctx);
 	return msg;
 }
@@ -893,7 +897,8 @@ static struct io_plan *handle_peer_revoke_and_ack(struct io_conn *conn,
 
 	/* Tell master about things this locks in, wait for response */
 	msg = got_revoke_msg(msg, peer->commit_index[REMOTE],
-			     &old_commit_secret, changed_htlcs);
+			     &old_commit_secret, &next_per_commit,
+			     changed_htlcs);
 	master_sync_reply(peer, take(msg),
 			  WIRE_CHANNEL_GOT_REVOKE_REPLY,
 			  handle_reply_wake_peer);
@@ -1549,6 +1554,7 @@ static struct io_plan *req_in(struct io_conn *conn, struct daemon_conn *master)
 		case WIRE_CHANNEL_SENDING_COMMITSIG_REPLY:
 		case WIRE_CHANNEL_GOT_COMMITSIG_REPLY:
 		case WIRE_CHANNEL_GOT_REVOKE_REPLY:
+		case WIRE_CHANNEL_GOT_FUNDING_LOCKED:
 			break;
 		}
 		status_failed(WIRE_CHANNEL_BAD_COMMAND, "%u %s", t,

lightningd/channel/channel_wire.csv

@@ -17,8 +17,7 @@ channel_normal_operation,1001
 #include <lightningd/cryptomsg.h>
 #include <lightningd/channel_config.h>
 
-# Begin!  You're still waiting for the tx to be buried though (passes
-# gossipd-client fd)
+# Begin!  (passes gossipd-client fd)
 channel_init,1
 channel_init,,funding_txid,struct sha256_double
 channel_init,,funding_txout,2
@@ -89,6 +88,10 @@ channel_ping_reply,,totlen,u16
 # Channeld tells the master that the channel has been announced
 channel_announced,12
 
+# When we receive funding_locked.
+channel_got_funding_locked,19
+channel_got_funding_locked,,next_per_commit_point,struct pubkey
+
 # When we send a commitment_signed message, tell master.
 channel_sending_commitsig,20
 channel_sending_commitsig,,commitnum,u64
@@ -126,6 +129,7 @@ channel_got_commitsig_reply,121
 channel_got_revoke,22
 channel_got_revoke,,revokenum,u64
 channel_got_revoke,,per_commitment_secret,struct sha256
+channel_got_revoke,,next_per_commit_point,struct pubkey
 # RCVD_ADD_ACK_REVOCATION, RCVD_REMOVE_ACK_REVOCATION, RCVD_ADD_REVOCATION, RCVD_REMOVE_REVOCATION
 channel_got_revoke,,num_changed,u16
 channel_got_revoke,,changed,num_changed*struct changed_htlc

lightningd/peer_control.c

@@ -34,15 +34,6 @@
 #include <wire/gen_onion_wire.h>
 #include <wire/gen_peer_wire.h>
 
-/* FIXME: Define serialization primitive for this? */
-struct channel_info {
-	secp256k1_ecdsa_signature commit_sig;
-	struct channel_config their_config;
-	struct pubkey remote_fundingkey;
-	struct basepoints theirbase;
-	struct pubkey their_per_commit_point;
-};
-
 static void destroy_peer(struct peer *peer)
 {
 	list_del_from(&peer->ld->peers, &peer->list);
@@ -305,6 +296,7 @@ void add_peer(struct lightningd *ld, u64 unique_id,
 	peer->balance = NULL;
 	peer->state = UNINITIALIZED;
 	peer->channel_info = NULL;
+	peer->next_per_commitment_point = NULL;
 	shachain_init(&peer->their_shachain);
 
 	idname = type_to_string(peer, struct pubkey, id);
@@ -849,6 +841,25 @@ static void peer_channel_announced(struct peer *peer, const u8 *msg)
 	tal_free(tmpctx);
 }
 
+static int peer_got_funding_locked(struct peer *peer, const u8 *msg)
+{
+	struct pubkey next_per_commitment_point;
+
+	if (!fromwire_channel_got_funding_locked(msg, NULL,
+						 &next_per_commitment_point)) {
+		log_broken(peer->log, "bad channel_got_funding_locked %s",
+			   tal_hex(peer, msg));
+		return -1;
+	}
+
+	/* In case of re-transmit. */
+	peer->next_per_commitment_point
+		= tal_free(peer->next_per_commitment_point);
+	peer->next_per_commitment_point
+		= tal_dup(peer, struct pubkey, &next_per_commitment_point);
+	return 0;
+}
+
 static int channel_msg(struct subd *sd, const u8 *msg, const int *unused)
 {
 	enum channel_wire_type t = fromwire_peektype(msg);
@@ -867,6 +878,8 @@ static int channel_msg(struct subd *sd, const u8 *msg, const int *unused)
 	case WIRE_CHANNEL_ANNOUNCED:
 		peer_channel_announced(sd->peer, msg);
 		break;
+	case WIRE_CHANNEL_GOT_FUNDING_LOCKED:
+		return peer_got_funding_locked(sd->peer, msg);
 
 	/* We never see fatal ones. */
 	case WIRE_CHANNEL_BAD_COMMAND:

lightningd/peer_control.h

@@ -75,6 +75,9 @@ struct peer {
 	/* Keys for channel. */
 	struct channel_info *channel_info;
 
+	/* Their next per-commit point, if known. */
+	struct pubkey *next_per_commitment_point;
+
 	/* Secret seed (FIXME: Move to hsm!) */
 	struct privkey *seed;
 

lightningd/peer_htlcs.c

@@ -908,6 +908,17 @@ int peer_got_commitsig(struct peer *peer, const u8 *msg)
 	return 0;
 }
 
+/* Shuffle them over, forgetting the ancient one. */
+static void update_per_commit_point(struct peer *peer,
+				    const struct pubkey *per_commitment_point)
+{
+	peer->channel_info->their_per_commit_point
+		= *peer->next_per_commitment_point;
+	tal_free(peer->next_per_commitment_point);
+	peer->next_per_commitment_point = tal_dup(peer, struct pubkey,
+						  per_commitment_point);
+}
+
 /* FIXME: add to ccan/shachain */
 static shachain_index_t shachain_next_index(const struct shachain *chain)
 {
@@ -921,12 +932,14 @@ int peer_got_revoke(struct peer *peer, const u8 *msg)
 {
 	u64 revokenum, shachainidx;
 	struct sha256 per_commitment_secret;
+	struct pubkey next_per_commitment_point;
 	struct changed_htlc *changed;
 	enum onion_type *failcodes;
 	size_t i;
 
 	if (!fromwire_channel_got_revoke(msg, msg, NULL,
 					 &revokenum, &per_commitment_secret,
+					 &next_per_commitment_point,
 					 &changed)) {
 		log_broken(peer->log, "bad fromwire_channel_got_revoke %s",
 			   tal_hex(peer, msg));
@@ -985,7 +998,10 @@ int peer_got_revoke(struct peer *peer, const u8 *msg)
 		return -1;
 	}
 
-	/* FIXME: Commit shachain to db */
+	/* FIXME: Check per_commitment_secret -> per_commit_point */
+	update_per_commit_point(peer, &next_per_commitment_point);
+
+	/* FIXME: Commit shachain and next_per_commit_point to db */
 
 	/* Tell it we've committed, and to go ahead with revoke. */
 	msg = towire_channel_got_revoke_reply(msg);

lightningd/peer_htlcs.h

@@ -4,6 +4,15 @@
 #include "config.h"
 #include <ccan/short_types/short_types.h>
 
+/* FIXME: Define serialization primitive for this? */
+struct channel_info {
+	secp256k1_ecdsa_signature commit_sig;
+	struct channel_config their_config;
+	struct pubkey remote_fundingkey;
+	struct basepoints theirbase;
+	struct pubkey their_per_commit_point;
+};
+
 int peer_sending_commitsig(struct peer *peer, const u8 *msg);
 int peer_got_commitsig(struct peer *peer, const u8 *msg);
 int peer_got_revoke(struct peer *peer, const u8 *msg);