Splice Interop

channeld/channeld_wire.csv

@@ -255,6 +255,7 @@ msgdata,channeld_splice_feerate_error,too_high,bool,
 
 # channeld->master: Add an inflight to the DB
 msgtype,channeld_add_inflight,7216
+msgdata,channeld_add_inflight,remote_funding,pubkey,
 msgdata,channeld_add_inflight,tx_id,bitcoin_txid,
 msgdata,channeld_add_inflight,tx_outnum,u32,
 msgdata,channeld_add_inflight,feerate,u32,
@@ -287,7 +288,7 @@ msgdata,channeld_splice_state_error,state_error,wirestring,
 msgtype,channeld_splice_abort,7223
 msgdata,channeld_splice_abort,did_i_initiate,bool,
 msgdata,channeld_splice_abort,inflight_outpoint,?bitcoin_outpoint,
-msgdata,channeld_splice_abort,reason,?wirestring,
+msgdata,channeld_splice_abort,reason,wirestring,
 
 # master->channeld: Please enter stfu mode
 msgtype,channeld_stfu,7224

channeld/full_channel.c

@@ -309,13 +309,17 @@ struct bitcoin_tx **channel_txs(const tal_t *ctx,
 				enum side side,
 				s64 splice_amnt,
 				s64 remote_splice_amnt,
-				int *other_anchor_outnum)
+				int *other_anchor_outnum,
+				const struct pubkey funding_pubkeys[NUM_SIDES])
 {
 	struct bitcoin_tx **txs;
 	const struct htlc **committed;
 	struct keyset keyset;
 	struct amount_msat side_pay, other_side_pay;
 
+	if (!funding_pubkeys)
+		funding_pubkeys = channel->funding_pubkey;
+
 	if (!derive_keyset(per_commitment_point,
 			   &channel->basepoints[side],
 			   &channel->basepoints[!side],
@@ -329,8 +333,8 @@ struct bitcoin_tx **channel_txs(const tal_t *ctx,
 	/* Generating and saving witness script required to spend
 	 * the funding output */
 	*funding_wscript = bitcoin_redeem_2of2(ctx,
-					      &channel->funding_pubkey[side],
-					      &channel->funding_pubkey[!side]);
+					      &funding_pubkeys[side],
+					      &funding_pubkeys[!side]);
 
 	side_pay = channel->view[side].owed[side];
 	other_side_pay = channel->view[side].owed[!side];
@@ -351,8 +355,8 @@ struct bitcoin_tx **channel_txs(const tal_t *ctx,
 	txs[0] = commit_tx(
 	    txs, funding,
 	    funding_sats,
-	    &channel->funding_pubkey[side],
-	    &channel->funding_pubkey[!side],
+	    &funding_pubkeys[side],
+	    &funding_pubkeys[!side],
 	    channel->opener,
 	    channel->config[!side].to_self_delay,
 	    channel->lease_expiry,
@@ -367,9 +371,9 @@ struct bitcoin_tx **channel_txs(const tal_t *ctx,
 
 	/* Set the remote/local pubkeys on the commitment tx psbt */
 	psbt_input_add_pubkey(txs[0]->psbt, 0,
-			      &channel->funding_pubkey[side], false /* is_taproot */);
+			      &funding_pubkeys[side], false /* is_taproot */);
 	psbt_input_add_pubkey(txs[0]->psbt, 0,
-			      &channel->funding_pubkey[!side], false /* is_taproot */);
+			      &funding_pubkeys[!side], false /* is_taproot */);
 
 	add_htlcs(&txs, *htlcmap, channel, &keyset, side);
 

channeld/full_channel.h

@@ -67,6 +67,7 @@ struct channel *new_full_channel(const tal_t *ctx,
  * @local_splice_amnt: how much is being spliced in (or out, if -ve) of local side.
  * @remote_splice_amnt: how much is being spliced in (or out, if -ve) of remote side.
  * @other_anchor_outnum: which output (-1 if none) is the !!side anchor
+ * @funding_pubkeys: The funding pubkeys (specify NULL to use channel's value).
  *
  * Returns the unsigned commitment transaction for the committed state
  * for @side, followed by the htlc transactions in output order and
@@ -84,7 +85,8 @@ struct bitcoin_tx **channel_txs(const tal_t *ctx,
 				enum side side,
 				s64 local_splice_amnt,
 				s64 remote_splice_amnt,
-				int *local_anchor_outnum);
+				int *local_anchor_outnum,
+				const struct pubkey funding_pubkeys[NUM_SIDES]);
 
 /**
  * actual_feerate: what is the actual feerate for the local side.

channeld/inflight.c

@@ -9,6 +9,7 @@ struct inflight *fromwire_inflight(const tal_t *ctx, const u8 **cursor, size_t *
 	struct inflight *inflight = tal(ctx, struct inflight);
 
 	fromwire_bitcoin_outpoint(cursor, max, &inflight->outpoint);
+	fromwire_pubkey(cursor, max, &inflight->remote_funding);
 	inflight->amnt = fromwire_amount_sat(cursor, max);
 	inflight->remote_tx_sigs = fromwire_bool(cursor, max);
 	inflight->psbt = fromwire_wally_psbt(inflight, cursor, max);
@@ -31,6 +32,7 @@ struct inflight *fromwire_inflight(const tal_t *ctx, const u8 **cursor, size_t *
 void towire_inflight(u8 **pptr, const struct inflight *inflight)
 {
 	towire_bitcoin_outpoint(pptr, &inflight->outpoint);
+	towire_pubkey(pptr, &inflight->remote_funding);
 	towire_amount_sat(pptr, inflight->amnt);
 	towire_bool(pptr, inflight->remote_tx_sigs);
 	towire_wally_psbt(pptr, inflight->psbt);
@@ -43,16 +45,3 @@ void towire_inflight(u8 **pptr, const struct inflight *inflight)
 	towire_bool(pptr, inflight->i_am_initiator);
 	towire_bool(pptr, inflight->force_sign_first);
 }
-
-void copy_inflight(struct inflight *dest, struct inflight *src)
-{
-	dest->outpoint = src->outpoint;
-	dest->amnt = src->amnt;
-	dest->remote_tx_sigs = src->remote_tx_sigs;
-	dest->psbt = src->psbt ? clone_psbt(dest, src->psbt): NULL;
-	dest->splice_amnt = src->splice_amnt;
-	dest->last_tx = src->last_tx ? clone_bitcoin_tx(dest, src->last_tx) : NULL;
-	dest->last_sig = src->last_sig;
-	dest->i_am_initiator = src->i_am_initiator;
-	dest->force_sign_first = src->force_sign_first;
-}

channeld/inflight.h

@@ -2,11 +2,13 @@
 #define LIGHTNING_CHANNELD_INFLIGHT_H
 
 #include "config.h"
+#include <bitcoin/pubkey.h>
 #include <bitcoin/tx.h>
 #include <common/amount.h>
 
 struct inflight {
 	struct bitcoin_outpoint outpoint;
+	struct pubkey remote_funding;
 	struct amount_sat amnt;
 	bool remote_tx_sigs;
 	struct wally_psbt *psbt;
@@ -22,6 +24,4 @@ struct inflight {
 struct inflight *fromwire_inflight(const tal_t *ctx, const u8 **cursor, size_t *max);
 void towire_inflight(u8 **pptr, const struct inflight *inflight);
 
-void copy_inflight(struct inflight *dest, struct inflight *src);
-
 #endif /* LIGHTNING_CHANNELD_INFLIGHT_H */

channeld/splice.h

@@ -31,6 +31,8 @@ struct splice_state *splice_state_new(const tal_t *ctx);
 /* An active splice negotiation. Born when splice beings and dies when a splice
  * negotation has finished */
 struct splicing {
+	/* The remote side's rotated funding pubkey */
+	struct pubkey remote_funding_pubkey;
 	/* The opener side's relative balance change */
 	s64 opener_relative;
 	/* The accepter side's relative balance change */

channeld/test/run-full_channel.c

@@ -555,7 +555,7 @@ int main(int argc, const char *argv[])
 	txs = channel_txs(tmpctx, &funding, funding_amount,
 			  &htlc_map, NULL, &funding_wscript_alt,
 			  lchannel, &local_per_commitment_point, 42, LOCAL, 0, 0,
-			  &local_anchor);
+			  &local_anchor, NULL);
 	assert(tal_count(txs) == 1);
 	assert(tal_count(htlc_map) == 2);
 	assert(scripteq(funding_wscript_alt, funding_wscript));
@@ -564,7 +564,7 @@ int main(int argc, const char *argv[])
 	txs2 = channel_txs(tmpctx, &funding, funding_amount,
 			   &htlc_map, NULL, &funding_wscript,
 			   rchannel, &local_per_commitment_point, 42, REMOTE, 0, 0,
-			   &local_anchor);
+			   &local_anchor, NULL);
 	txs_must_be_eq(txs, txs2);
 
 	/* BOLT #3:
@@ -593,12 +593,12 @@ int main(int argc, const char *argv[])
 	txs = channel_txs(tmpctx, &funding, funding_amount,
 			  &htlc_map, NULL, &funding_wscript,
 			  lchannel, &local_per_commitment_point, 42, LOCAL, 0, 0,
-			  &local_anchor);
+			  &local_anchor, NULL);
 	assert(tal_count(txs) == 1);
 	txs2 = channel_txs(tmpctx, &funding, funding_amount,
 			   &htlc_map, NULL, &funding_wscript,
 			   rchannel, &local_per_commitment_point, 42, REMOTE, 0, 0,
-			   &local_anchor);
+			   &local_anchor, NULL);
 	txs_must_be_eq(txs, txs2);
 
 	update_feerate(lchannel, feerate_per_kw[LOCAL]);
@@ -615,12 +615,12 @@ int main(int argc, const char *argv[])
 	txs = channel_txs(tmpctx, &funding, funding_amount,
 			  &htlc_map, NULL, &funding_wscript,
 			  lchannel, &local_per_commitment_point, 42, LOCAL, 0, 0,
-			  &local_anchor);
+			  &local_anchor, NULL);
 	assert(tal_count(txs) == 6);
 	txs2 = channel_txs(tmpctx, &funding, funding_amount,
 			   &htlc_map, NULL, &funding_wscript,
 			   rchannel, &local_per_commitment_point, 42, REMOTE, 0, 0,
-			   &local_anchor);
+			   &local_anchor, NULL);
 	txs_must_be_eq(txs, txs2);
 
 	/* FIXME: Compare signatures! */
@@ -695,14 +695,14 @@ int main(int argc, const char *argv[])
 				  &htlc_map, NULL, &funding_wscript,
 				  lchannel, &local_per_commitment_point, 42,
 				  LOCAL, 0, 0,
-				  &local_anchor);
+				  &local_anchor, NULL);
 		tx_must_be_eq(txs[0], raw_tx);
 
 		txs2 = channel_txs(tmpctx, &funding, funding_amount,
 				   &htlc_map, NULL, &funding_wscript,
 				   rchannel, &local_per_commitment_point,
 				   42, REMOTE, 0, 0,
-				   &local_anchor);
+				   &local_anchor, NULL);
 		txs_must_be_eq(txs, txs2);
 	}
 

common/interactivetx.c

@@ -64,6 +64,8 @@ struct interactivetx_context *new_interactivetx_context(const tal_t *ctx,
 	ictx->our_role = our_role;
 	ictx->pps = pps;
 	ictx->channel_id = channel_id;
+	ictx->shared_outpoint = NULL;
+	ictx->funding_tx = NULL;
 	ictx->tx_add_input_count = 0;
 	ictx->tx_add_output_count = 0;
 	ictx->next_update_fn = default_next_update;
@@ -208,6 +210,7 @@ static char *send_next(const tal_t *ctx,
 
 	if (tal_count(set->added_ins) != 0) {
 		const struct input_set *in = &set->added_ins[0];
+		struct bitcoin_outpoint point;
 		u8 *prevtx;
 
 		if (!psbt_get_serial_id(&in->input.unknowns, &serial_id))
@@ -220,9 +223,24 @@ static char *send_next(const tal_t *ctx,
 			return "interactivetx ADD_INPUT PSBT needs the previous"
 			       " transaction set.";
 
-		msg = towire_tx_add_input(NULL, cid, serial_id,
-					  prevtx, in->input.index,
-					  in->input.sequence);
+		wally_psbt_input_get_outpoint(&in->input, &point);
+
+		/* If this the shared channel input, we send funding txid in
+		 * in tlvs and do not send prevtx */
+ 		if (ictx->shared_outpoint
+ 			&& bitcoin_outpoint_eq(&point, ictx->shared_outpoint)) {
+			struct tlv_tx_add_input_tlvs *tlvs = tal(tmpctx, struct tlv_tx_add_input_tlvs);
+			tlvs->shared_input_txid = tal_dup(tlvs,
+							  struct bitcoin_txid,
+							  &point.txid);
+ 			msg = towire_tx_add_input(NULL, cid, serial_id,
+						  NULL, in->input.index,
+						  in->input.sequence, tlvs);
+ 		} else {
+			msg = towire_tx_add_input(NULL, cid, serial_id,
+						  prevtx, in->input.index,
+						  in->input.sequence, NULL);
+		}
 
 		tal_arr_remove(&set->added_ins, 0);
 	}
@@ -417,12 +435,14 @@ char *process_interactivetx_updates(const tal_t *ctx,
 			size_t len;
 			struct bitcoin_tx *tx;
 			struct bitcoin_outpoint outpoint;
+			struct tlv_tx_add_input_tlvs *tlvs;
 
 			if (!fromwire_tx_add_input(ctx, msg, &cid,
 						   &serial_id,
 						   cast_const2(u8 **,
 							       &tx_bytes),
-						   &outpoint.n, &sequence))
+						   &outpoint.n, &sequence,
+						   &tlvs))
 				return tal_fmt(ctx,
 					       "Parsing tx_add_input %s",
 					       tal_hex(ctx, msg));
@@ -459,13 +479,30 @@ char *process_interactivetx_updates(const tal_t *ctx,
 				return tal_fmt(ctx, "Duplicate serial_id rcvd"
 					       " %"PRIu64, serial_id);
 
-			/* Convert tx_bytes to a tx! */
-			len = tal_bytelen(tx_bytes);
-			tx = pull_bitcoin_tx_only(ctx, &tx_bytes, &len);
-
-			if (!tx || len != 0)
-				return tal_fmt(ctx, "Invalid tx sent. len: %d",
-					       (int)len);
+			/* For our shared input only, we will fill in prevtx */
+			if (ictx->shared_outpoint && tlvs->shared_input_txid) {
+				if (!bitcoin_txid_eq(tlvs->shared_input_txid,
+						     &ictx->shared_outpoint->txid))
+					return tal_fmt(ctx, "funding_txid value"
+						       " %s unrecognized."
+						       " Should be %s",
+						       fmt_bitcoin_txid(ctx, tlvs->shared_input_txid),
+						       fmt_bitcoin_txid(ctx, &ictx->shared_outpoint->txid));
+				if (!ictx->funding_tx)
+					return tal_fmt(ctx, "Internal error"
+						       " did not set"
+						       " interactivetx"
+						       " funding_tx");
+				tx = ictx->funding_tx;
+			}
+			else {
+				/* Convert tx_bytes to a tx! */
+				len = tal_bytelen(tx_bytes);
+				tx = pull_bitcoin_tx_only(ctx, &tx_bytes, &len);
+				if (!tx || len != 0)
+					return tal_fmt(ctx, "Invalid tx sent. len: %d",
+						       (int)len);
+			}
 
 			if (outpoint.n >= tx->wtx->num_outputs)
 				return tal_fmt(ctx,

common/interactivetx.h

@@ -30,6 +30,14 @@ struct interactivetx_context {
 	struct per_peer_state *pps;
 	struct channel_id channel_id;
 
+	/* The existing funding outpoint of a channel being spliced.
+	 * This input will send funding_txid instead of prevtx. */
+	struct bitcoin_outpoint *shared_outpoint;
+
+	/* When receiving `tx_add_input` we will fill in prevtx using this
+	 * value when `shared_outpoint`'s txid matches */
+	struct bitcoin_tx *funding_tx;
+
 	/* Track how many of each tx collab msg we receive */
 	u16 tx_add_input_count, tx_add_output_count;
 

common/jsonrpc_errors.h

@@ -84,6 +84,7 @@ enum jsonrpc_errcode {
 	SPLICE_LOW_FEE = 359,
 	SPLICE_HIGH_FEE = 360,
 	SPLICE_ABORT = 362,
+	SPLICE_CHANNEL_ERROR = 363,
 
 	/* `connect` errors */
 	CONNECT_NO_KNOWN_ADDRESS = 400,

common/wire_error.c

@@ -72,6 +72,43 @@ u8 *towire_warningfmt(const tal_t *ctx,
 	return msg;
 }
 
+u8 *towire_abortfmtv(const tal_t *ctx,
+		     const struct channel_id *channel,
+		     const char *fmt,
+		     va_list ap)
+{
+	/* BOLT #1:
+	 *
+	 * The channel is referred to by `channel_id`, unless `channel_id` is
+	 * 0 (i.e. all bytes are 0), in which case it refers to all
+	 * channels. */
+	static const struct channel_id all_channels;
+	char *estr;
+	u8 *msg;
+
+	estr = tal_vfmt(ctx, fmt, ap);
+	/* We need tal_len to work, so we use copy. */
+	msg = towire_tx_abort(ctx, channel ? channel : &all_channels,
+			      (u8 *)tal_dup_arr(estr, char, estr, strlen(estr), 0));
+	tal_free(estr);
+
+	return msg;
+}
+
+u8 *towire_abortfmt(const tal_t *ctx,
+		    const struct channel_id *channel,
+		    const char *fmt, ...)
+{
+	va_list ap;
+	u8 *msg;
+
+	va_start(ap, fmt);
+	msg = towire_abortfmtv(ctx, channel, fmt, ap);
+	va_end(ap);
+
+	return msg;
+}
+
 bool channel_id_is_all(const struct channel_id *channel_id)
 {
 	return memeqzero(channel_id, sizeof(*channel_id));