channeld: Code to implement splicing

Update the lightningd <-> channeld interface with lots of new commands to needed to facilitate spicing.

Implement the channeld splicing protocol leveraging the interactivetx protocol.

Implement lightningd’s channel_control to support channeld in its splicing efforts.

Changelog-Added: Added the features to enable splicing & resizing of active channels.

wire/extracted_peer_06_funding_outpoint_sigs.patch

@@ -0,0 +1,18 @@
+--- wire/peer_exp_wire.csv	2022-06-22 19:07:24.000000000 -0500
++++ -	2022-06-30 16:00:51.000000000 -0500
+@@ -65,12 +57,15 @@
+ msgdata,tx_signatures,txid,sha256,
+ msgdata,tx_signatures,num_witnesses,u16,
+ msgdata,tx_signatures,witness_stack,witness_stack,num_witnesses
++msgdata,tx_signatures,tlvs,txsigs_tlvs,
+ subtype,witness_stack
+ subtypedata,witness_stack,num_input_witness,u16,
+ subtypedata,witness_stack,witness_element,witness_element,num_input_witness
+ subtype,witness_element
+ subtypedata,witness_element,len,u16,
+ subtypedata,witness_element,witness,byte,len
++tlvtype,txsigs_tlvs,funding_outpoint_sig,0
++tlvdata,txsigs_tlvs,funding_outpoint_sig,sig,byte,...
+ msgtype,tx_init_rbf,72
+ msgdata,tx_init_rbf,channel_id,channel_id,
+ msgdata,tx_init_rbf,locktime,u32,

wire/extracted_peer_10_upgradable.patch

@@ -1,10 +1,12 @@
 --- wire/peer_wire.csv	2021-05-09 15:44:59.166135652 +0930
 +++ wire/peer_wire.csv.raw	2021-05-11 09:59:31.695459756 +0930
-@@ -244,6 +140,15 @@
+@@ -244,6 +140,17 @@
  msgdata,channel_reestablish,next_revocation_number,u64,
  msgdata,channel_reestablish,your_last_per_commitment_secret,byte,32
  msgdata,channel_reestablish,my_current_per_commitment_point,point,
 +msgdata,channel_reestablish,tlvs,channel_reestablish_tlvs,
++tlvtype,channel_reestablish_tlvs,next_funding,0
++tlvdata,channel_reestablish_tlvs,next_funding,next_funding_txid,sha256,
 +tlvtype,channel_reestablish_tlvs,next_to_send,1
 +tlvdata,channel_reestablish_tlvs,next_to_send,commitment_number,tu64,
 +tlvtype,channel_reestablish_tlvs,desired_channel_type,3

wire/fromwire.c

@@ -280,3 +280,4 @@ void fromwire_siphash_seed(const u8 **cursor, size_t *max,
 {
 	fromwire(cursor, max, seed, sizeof(*seed));
 }
+

wire/peer_wire.c

@@ -50,6 +50,9 @@ static bool unknown_type(enum peer_wire t)
 	case WIRE_OPEN_CHANNEL2:
 	case WIRE_ACCEPT_CHANNEL2:
 	case WIRE_STFU:
+	case WIRE_SPLICE:
+	case WIRE_SPLICE_ACK:
+	case WIRE_SPLICE_LOCKED:
 		return false;
 	}
 	return true;
@@ -104,6 +107,9 @@ bool is_msg_for_gossipd(const u8 *cursor)
 	case WIRE_PEER_STORAGE:
 	case WIRE_YOUR_PEER_STORAGE:
 	case WIRE_STFU:
+	case WIRE_SPLICE:
+	case WIRE_SPLICE_ACK:
+	case WIRE_SPLICE_LOCKED:
 		break;
 	}
 	return false;
@@ -365,6 +371,30 @@ bool extract_channel_id(const u8 *in_pkt, struct channel_id *channel_id)
 		 * 2. data:
 		 *     * [`channel_id`:`channel_id`]
 		 */
+	case WIRE_SPLICE:
+		/* BOLT-splice #2:
+		 * 1. type: 74 (`splice`)
+		 * 2. data:
+		 *     * [`chain_hash`:`chain_hash`]
+		 *     * [`channel_id`:`channel_id`]
+		 *     * [`u32`:`funding_feerate_perkw`]
+		 *     * [`point`:`funding_pubkey`]
+		 */
+	case WIRE_SPLICE_ACK:
+		/* BOLT-splice #2:
+		 * 1. type: 76 (`splice_ack`)
+		 * 2. data:
+		 *     * [`chain_hash`:`chain_hash`]
+		 *     * [`channel_id`:`channel_id`]
+		 *     * [`point`:`funding_pubkey`]
+		 */
+	case WIRE_SPLICE_LOCKED:
+		/* BOLT-splice #2:
+		 * 1. type: 78 (`splice_locked`)
+		 * 2. data:
+		 *     * [`chain_hash`:`chain_hash`]
+		 *     * [`channel_id`:`channel_id`]
+		 */
 		return fromwire_channel_id(&cursor, &max, channel_id);
 	}
 	return false;

wire/peer_wire.csv

@@ -66,6 +66,9 @@ msgdata,tx_signatures,witnesses,witness,num_witnesses
 subtype,witness
 subtypedata,witness,len,u16,
 subtypedata,witness,witness_data,byte,len
+msgdata,tx_signatures,tlvs,txsigs_tlvs,
+tlvtype,txsigs_tlvs,funding_outpoint_sig,0
+tlvdata,txsigs_tlvs,funding_outpoint_sig,sig,byte,...
 msgtype,tx_init_rbf,72
 msgdata,tx_init_rbf,channel_id,channel_id,
 msgdata,tx_init_rbf,locktime,u32,
@@ -203,6 +206,20 @@ subtypedata,lease_rates,channel_fee_max_base_msat,tu32,
 msgtype,stfu,2
 msgdata,stfu,channel_id,channel_id,
 msgdata,stfu,initiator,u8,
+msgtype,splice,75
+msgdata,splice,channel_id,channel_id,
+msgdata,splice,chain_hash,chain_hash,
+msgdata,splice,relative_satoshis,s64,
+msgdata,splice,funding_feerate_perkw,u32,
+msgdata,splice,locktime,u32,
+msgdata,splice,funding_pubkey,point,
+msgtype,splice_ack,76
+msgdata,splice_ack,channel_id,channel_id,
+msgdata,splice_ack,chain_hash,chain_hash,
+msgdata,splice_ack,relative_satoshis,s64,
+msgdata,splice_ack,funding_pubkey,point,
+msgtype,splice_locked,77,
+msgdata,splice_locked,channel_id,channel_id,
 msgtype,shutdown,38
 msgdata,shutdown,channel_id,channel_id,
 msgdata,shutdown,len,u16,
@@ -247,6 +264,9 @@ msgdata,commitment_signed,channel_id,channel_id,
 msgdata,commitment_signed,signature,signature,
 msgdata,commitment_signed,num_htlcs,u16,
 msgdata,commitment_signed,htlc_signature,signature,num_htlcs
+msgdata,commitment_signed,splice_channel_id,commitment_signed_tlvs,
+tlvtype,commitment_signed_tlvs,splice_info,0
+tlvdata,commitment_signed_tlvs,splice_info,splice_channel_id,channel_id,
 msgtype,revoke_and_ack,133
 msgdata,revoke_and_ack,channel_id,channel_id,
 msgdata,revoke_and_ack,per_commitment_secret,byte,32

wire/test/run-peer-wire.c

@@ -40,6 +40,11 @@ static void set_scid(struct short_channel_id *scid)
 	memset(scid, 2, sizeof(struct short_channel_id));
 }
 
+static void set_cid(struct channel_id *cid)
+{
+	memset(cid, 2, sizeof(struct channel_id));
+}
+
 /* Size up to field. */
 #define upto_field(p, field)				\
 	((char *)&(p)->field - (char *)(p))
@@ -160,6 +165,7 @@ struct msg_commitment_signed {
 	struct channel_id channel_id;
 	secp256k1_ecdsa_signature signature;
 	secp256k1_ecdsa_signature *htlc_signature;
+	struct tlv_commitment_signed_tlvs *tlvs;
 };
 struct msg_node_announcement {
 	secp256k1_ecdsa_signature signature;
@@ -525,17 +531,20 @@ static void *towire_struct_commitment_signed(const tal_t *ctx,
 	return towire_commitment_signed(ctx,
 					&s->channel_id,
 					&s->signature,
-					s->htlc_signature);
+					s->htlc_signature,
+					s->tlvs);
 }
 
 static struct msg_commitment_signed *fromwire_struct_commitment_signed(const tal_t *ctx, const void *p)
 {
 	struct msg_commitment_signed *s = tal(ctx, struct msg_commitment_signed);
+	s->tlvs = tlv_commitment_signed_tlvs_new(ctx);
 
 	if (!fromwire_commitment_signed(s, p,
 				&s->channel_id,
 				&s->signature,
-				&s->htlc_signature))
+				&s->htlc_signature,
+				&s->tlvs))
 		return tal_free(s);
 	return s;
 }
@@ -781,7 +790,8 @@ static bool commitment_signed_eq(const struct msg_commitment_signed *a,
 			  const struct msg_commitment_signed *b)
 {
 	return eq_upto(a, b, htlc_signature)
-		&& eq_var(a, b, htlc_signature);
+		&& eq_var(a, b, htlc_signature)
+		&& eq_tlv(a, b, splice_info, channel_id_eq);
 }
 
 static bool funding_signed_eq(const struct msg_funding_signed *a,
@@ -1007,11 +1017,14 @@ int main(int argc, char *argv[])
 	memset(&cs, 2, sizeof(cs));
 	cs.htlc_signature = tal_arr(ctx, secp256k1_ecdsa_signature, 2);
 	memset(cs.htlc_signature, 2, sizeof(secp256k1_ecdsa_signature)*2);
+	cs.tlvs = tlv_commitment_signed_tlvs_new(tmpctx);
+	cs.tlvs->splice_info = tal(ctx, struct channel_id);
+	set_cid(cs.tlvs->splice_info);
 
 	msg = towire_struct_commitment_signed(ctx, &cs);
 	cs2 = fromwire_struct_commitment_signed(ctx, msg);
 	assert(commitment_signed_eq(&cs, cs2));
-	test_corruption(&cs, cs2, commitment_signed);
+	test_corruption_tlv(&cs, cs2, commitment_signed);
 
 	memset(&fs, 2, sizeof(fs));
 

wire/towire.c

@@ -4,6 +4,7 @@
 #include <ccan/crypto/siphash24/siphash24.h>
 #include <ccan/endian/endian.h>
 #include <ccan/mem/mem.h>
+#include <channeld/inflight.h>
 #include <common/utils.h>
 
 void towire(u8 **pptr, const void *data, size_t len)