Send/receive cltv_expiry_delta in open/accept channel.

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

common/channel_config.h

@@ -19,6 +19,7 @@
  *    * [`4`:`feerate_per_kw`]
  *    * [`2`:`to_self_delay`]
  *    * [`2`:`max_accepted_htlcs`]
+ *    * [`2`:`cltv_expiry_delta`]
  *...
  * 1. type: 33 (`accept_channel`)
  * 2. data:
@@ -30,6 +31,7 @@
  *    * [`4`:`minimum_depth`]
  *    * [`2`:`to_self_delay`]
  *    * [`2`:`max_accepted_htlcs`]
+ *    * [`2`:`cltv_expiry_delta`]
  */
 struct channel_config {
 	/* Database ID */

lightningd/peer_control.c

@@ -2266,7 +2266,8 @@ static bool opening_funder_finished(struct subd *opening, const u8 *resp,
 					   &fc->peer->minimum_depth,
 					   &channel_info->remote_fundingkey,
 					   &funding_txid,
-					   &channel_info->feerate_per_kw)) {
+					   &channel_info->feerate_per_kw,
+					   &channel_info->their_cltv_expiry_delta)) {
 		peer_internal_error(fc->peer, "bad shutdown_complete: %s",
 				    tal_hex(resp, resp));
 		return false;
@@ -2387,7 +2388,8 @@ static bool opening_fundee_finished(struct subd *opening,
 					   &peer->push_msat,
 					   &peer->channel_flags,
 					   &channel_info->feerate_per_kw,
-					   &funding_signed)) {
+					   &funding_signed,
+					   &channel_info->their_cltv_expiry_delta)) {
 		log_broken(peer->log, "bad OPENING_FUNDEE_REPLY %s",
 			   tal_hex(reply, reply));
 		return false;
@@ -2528,7 +2530,8 @@ void peer_fundee_open(struct peer *peer, const u8 *from_peer,
 				  &peer->our_config,
 				  max_to_self_delay,
 				  min_effective_htlc_capacity_msat,
-				  cs, peer->seed);
+				  cs, peer->seed,
+				  ld->config.min_htlc_expiry);
 
 	subd_send_msg(peer->owner, take(msg));
 	/* FIXME: Expose the min_feerate_per_kw and max_feerate_per_kw in the config */
@@ -2602,7 +2605,8 @@ static bool gossip_peer_released(struct subd *gossip,
 				  &fc->peer->our_config,
 				  max_to_self_delay,
 				  min_effective_htlc_capacity_msat,
-				  &cs, fc->peer->seed);
+				  &cs, fc->peer->seed,
+				  ld->config.min_htlc_expiry);
 
 	subd_send_msg(opening, take(msg));
 

lightningd/peer_htlcs.c

@@ -537,7 +537,7 @@ static void forward_htlc(struct htlc_in *hin,
 
 	/* BOLT #4:
 	 *
-	 * If the cltv-expiry is too near, we tell them the the current channel
+	 * If the `cltv_expiry` is too near, we tell them the the current channel
 	 * setting for the outgoing channel:
 	 * 1. type: UPDATE|14 (`expiry_too_soon`)
 	 * 2. data:

lightningd/peer_htlcs.h

@@ -15,6 +15,7 @@ struct channel_info {
 	 * and the remote_per_commit is for the commit_tx we're modifying now. */
 	struct pubkey remote_per_commit, old_remote_per_commit;
 	u32 feerate_per_kw;
+	u16 their_cltv_expiry_delta;
 };
 
 /* Get all HTLCs for a peer, to send in init message. */

openingd/opening.c

@@ -199,6 +199,7 @@ static u8 *funder_channel(struct state *state,
 			  const struct pubkey *our_funding_pubkey,
 			  const struct basepoints *ours,
 			  u32 max_minimum_depth,
+			  u16 our_cltv_expiry_delta,
 			  u64 change_satoshis, u32 change_keyindex,
 			  u8 channel_flags,
 			  const struct utxo *utxos,
@@ -211,6 +212,7 @@ static u8 *funder_channel(struct state *state,
 	struct pubkey their_funding_pubkey, changekey;
 	secp256k1_ecdsa_signature sig;
 	u32 minimum_depth;
+	u16 their_cltv_expiry_delta;
 	const u8 *wscript;
 	struct bitcoin_tx *funding;
 	const struct utxo **utxomap;
@@ -249,12 +251,14 @@ static u8 *funder_channel(struct state *state,
 				  state->feerate_per_kw,
 				  state->localconf.to_self_delay,
 				  state->localconf.max_accepted_htlcs,
+				  our_cltv_expiry_delta,
 				  our_funding_pubkey,
 				  &ours->revocation,
 				  &ours->payment,
 				  &ours->delayed_payment,
 				  &state->next_per_commit[LOCAL],
 				  channel_flags);
+
 	if (!sync_crypto_write(&state->cs, PEER_FD, msg))
 		status_failed(STATUS_FAIL_PEER_IO,
 			      "Writing open_channel: %s", strerror(errno));
@@ -283,6 +287,7 @@ static u8 *funder_channel(struct state *state,
 				     &minimum_depth,
 				     &state->remoteconf->to_self_delay,
 				     &state->remoteconf->max_accepted_htlcs,
+				     &their_cltv_expiry_delta,
 				     &their_funding_pubkey,
 				     &theirs.revocation,
 				     &theirs.payment,
@@ -445,7 +450,8 @@ static u8 *funder_channel(struct state *state,
 					   minimum_depth,
 					   &their_funding_pubkey,
 					   &state->funding_txid,
-					   state->feerate_per_kw);
+					   state->feerate_per_kw,
+					   their_cltv_expiry_delta);
 }
 
 /* This is handed the message the peer sent which caused gossip to stop:
@@ -454,6 +460,7 @@ static u8 *fundee_channel(struct state *state,
 			  const struct pubkey *our_funding_pubkey,
 			  const struct basepoints *ours,
 			  u32 minimum_depth,
+			  u16 our_cltv_expiry_delta,
 			  u32 min_feerate, u32 max_feerate, const u8 *peer_msg)
 {
 	struct channel_id id_in;
@@ -465,6 +472,7 @@ static u8 *fundee_channel(struct state *state,
 	u8 *msg;
 	const u8 *wscript;
 	u8 channel_flags;
+	u16 their_cltv_expiry_delta;
 
 	state->remoteconf = tal(state, struct channel_config);
 
@@ -485,6 +493,7 @@ static u8 *fundee_channel(struct state *state,
 				   &state->feerate_per_kw,
 				   &state->remoteconf->to_self_delay,
 				   &state->remoteconf->max_accepted_htlcs,
+				   &their_cltv_expiry_delta,
 				   &their_funding_pubkey,
 				   &theirs.revocation,
 				   &theirs.payment,
@@ -556,6 +565,7 @@ static u8 *fundee_channel(struct state *state,
 				    minimum_depth,
 				    state->localconf.to_self_delay,
 				    state->localconf.max_accepted_htlcs,
+				    our_cltv_expiry_delta,
 				    our_funding_pubkey,
 				    &ours->revocation,
 				    &ours->payment,
@@ -668,7 +678,8 @@ static u8 *fundee_channel(struct state *state,
 					   state->push_msat,
 					   channel_flags,
 					   state->feerate_per_kw,
-					   msg);
+					   msg,
+					   their_cltv_expiry_delta);
 }
 
 #ifndef TESTING
@@ -687,6 +698,7 @@ int main(int argc, char *argv[])
 	struct utxo *utxos;
 	struct ext_key bip32_base;
 	u32 network_index;
+	u16 our_cltv_expiry_delta;
 
 	if (argc == 2 && streq(argv[1], "--version")) {
 		printf("%s\n", version());
@@ -708,7 +720,8 @@ int main(int argc, char *argv[])
 				   &state->max_to_self_delay,
 				   &state->min_effective_htlc_capacity_msat,
 				   &state->cs,
-				   &seed))
+				   &seed,
+				   &our_cltv_expiry_delta))
 		master_badmsg(WIRE_OPENING_INIT, msg);
 
 	tal_free(msg);
@@ -741,13 +754,15 @@ int main(int argc, char *argv[])
 				    &change_satoshis, &change_keyindex,
 				    &channel_flags, &utxos, &bip32_base))
 		msg = funder_channel(state, &our_funding_pubkey, &our_points,
-				     max_minimum_depth, change_satoshis,
-				     change_keyindex, channel_flags,
+				     max_minimum_depth, our_cltv_expiry_delta,
+				     change_satoshis, change_keyindex,
+				     channel_flags,
 				     utxos, &bip32_base);
 	else if (fromwire_opening_fundee(state, msg, NULL, &minimum_depth,
 					 &min_feerate, &max_feerate, &peer_msg))
 		msg = fundee_channel(state, &our_funding_pubkey, &our_points,
-				   minimum_depth, min_feerate, max_feerate,
+				     minimum_depth, our_cltv_expiry_delta,
+				     min_feerate, max_feerate,
 				     peer_msg);
 	else
 		status_failed(STATUS_FAIL_MASTER_IO,

openingd/opening_wire.csv

@@ -11,6 +11,7 @@ opening_init,,min_effective_htlc_capacity_msat,u64
 opening_init,,crypto_state,struct crypto_state
 # Seed to generate all the keys from
 opening_init,,seed,struct privkey
+opening_init,,our_cltv_expiry_delta,u16
 
 #include <common/bip32.h>
 #include <common/htlc_wire.h>
@@ -42,6 +43,7 @@ opening_funder_reply,,minimum_depth,u32
 opening_funder_reply,,remote_fundingkey,struct pubkey
 opening_funder_reply,,funding_txid,struct sha256_double
 opening_funder_reply,,feerate_per_kw,u32
+opening_funder_reply,,their_cltv_expiry_delta,u16
 
 # This means they offer the open (contains their offer packet)
 opening_fundee,6003
@@ -71,3 +73,4 @@ opening_fundee_reply,,feerate_per_kw,u32
 # The (encrypted) funding signed message: send this and we're committed.
 opening_fundee_reply,,msglen,u16
 opening_fundee_reply,,funding_signed_msg,msglen*u8
+opening_fundee_reply,,their_cltv_expiry_delta,u16

wire/gen_peer_wire_csv

@@ -26,12 +26,13 @@ open_channel,104,htlc_minimum_msat,8
 open_channel,112,feerate_per_kw,4
 open_channel,116,to_self_delay,2
 open_channel,118,max_accepted_htlcs,2
-open_channel,120,funding_pubkey,33
-open_channel,153,revocation_basepoint,33
-open_channel,186,payment_basepoint,33
-open_channel,219,delayed_payment_basepoint,33
-open_channel,252,first_per_commitment_point,33
-open_channel,285,channel_flags,1
+open_channel,120,cltv_expiry_delta,2
+open_channel,122,funding_pubkey,33
+open_channel,155,revocation_basepoint,33
+open_channel,188,payment_basepoint,33
+open_channel,221,delayed_payment_basepoint,33
+open_channel,254,first_per_commitment_point,33
+open_channel,287,channel_flags,1
 accept_channel,33
 accept_channel,0,temporary_channel_id,32
 accept_channel,32,dust_limit_satoshis,8
@@ -41,11 +42,12 @@ accept_channel,56,htlc_minimum_msat,8
 accept_channel,64,minimum_depth,4
 accept_channel,68,to_self_delay,2
 accept_channel,70,max_accepted_htlcs,2
-accept_channel,72,funding_pubkey,33
-accept_channel,105,revocation_basepoint,33
-accept_channel,138,payment_basepoint,33
-accept_channel,171,delayed_payment_basepoint,33
-accept_channel,204,first_per_commitment_point,33
+accept_channel,72,cltv_expiry_delta,2
+accept_channel,74,funding_pubkey,33
+accept_channel,107,revocation_basepoint,33
+accept_channel,140,payment_basepoint,33
+accept_channel,173,delayed_payment_basepoint,33
+accept_channel,206,first_per_commitment_point,33
 funding_created,34
 funding_created,0,temporary_channel_id,32
 funding_created,32,funding_txid,32

wire/test/run-peer-wire.c

@@ -105,6 +105,7 @@ struct msg_accept_channel {
 	u32 minimum_depth;
 	u16 to_self_delay;
 	u16 max_accepted_htlcs;
+	u16 cltv_expiry_delta;
 	struct pubkey funding_pubkey;
 	struct pubkey revocation_basepoint;
 	struct pubkey payment_basepoint;
@@ -176,6 +177,7 @@ struct msg_open_channel {
 	u32 feerate_per_kw;
 	u16 to_self_delay;
 	u16 max_accepted_htlcs;
+	u16 cltv_expiry_delta;
 	struct pubkey funding_pubkey;
 	struct pubkey revocation_basepoint;
 	struct pubkey payment_basepoint;
@@ -269,6 +271,7 @@ static void *towire_struct_open_channel(const tal_t *ctx,
 				   s->feerate_per_kw,
 				   s->to_self_delay,
 				   s->max_accepted_htlcs,
+				   s->cltv_expiry_delta,
 				   &s->funding_pubkey,
 				   &s->revocation_basepoint,
 				   &s->payment_basepoint,
@@ -293,6 +296,7 @@ static struct msg_open_channel *fromwire_struct_open_channel(const tal_t *ctx, c
 				  &s->feerate_per_kw,
 				  &s->to_self_delay,
 				  &s->max_accepted_htlcs,
+				  &s->cltv_expiry_delta,
 				  &s->funding_pubkey,
 				  &s->revocation_basepoint,
 				  &s->payment_basepoint,
@@ -315,6 +319,7 @@ static void *towire_struct_accept_channel(const tal_t *ctx,
 				     s->minimum_depth,
 				     s->to_self_delay,
 				     s->max_accepted_htlcs,
+				     s->cltv_expiry_delta,
 				     &s->funding_pubkey,
 				     &s->revocation_basepoint,
 				     &s->payment_basepoint,
@@ -333,6 +338,7 @@ static struct msg_accept_channel *fromwire_struct_accept_channel(const tal_t *ct
 				    &s->channel_reserve_satoshis,
 				    &s->htlc_minimum_msat,
 				    &s->minimum_depth,
+				    &s->cltv_expiry_delta,
 				    &s->to_self_delay,
 				    &s->max_accepted_htlcs,
 				    &s->funding_pubkey,
@@ -799,7 +805,7 @@ static bool revoke_and_ack_eq(const struct msg_revoke_and_ack *a,
 static bool open_channel_eq(const struct msg_open_channel *a,
 			    const struct msg_open_channel *b)
 {
-	return eq_with(a, b, max_accepted_htlcs)
+	return eq_with(a, b, cltv_expiry_delta)
 		&& eq_between(a, b, funding_pubkey, channel_flags);
 }
 
@@ -813,7 +819,7 @@ static bool channel_update_eq(const struct msg_channel_update *a,
 static bool accept_channel_eq(const struct msg_accept_channel *a,
 			      const struct msg_accept_channel *b)
 {
-	return eq_with(a, b, max_accepted_htlcs)
+	return eq_with(a, b, cltv_expiry_delta)
 		&& eq_between(a, b, funding_pubkey, first_per_commitment_point);
 }