Update to new spec: differentiate channel_id and short_channel_id.

The spec 4af8e1841151f0c6e8151979d6c89d11839b2f65 uses a 32-byte 'channel-id'
field, not to be confused with the 8-byte short ID used by gossip.  Rename
appropriately, and update to the new handshake protocol.

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

daemon/p2p_announce.c

@@ -19,19 +19,19 @@ static void broadcast_channel_update(struct lightningd_state *dstate, struct pee
 	struct txlocator *loc;
 	u8 *serialized;
 	secp256k1_ecdsa_signature signature;
-	struct channel_id channel_id;
+	struct short_channel_id short_channel_id;
 	u32 timestamp = time_now().ts.tv_sec;
 	const tal_t *tmpctx = tal_tmpctx(dstate);
 
 	loc = locate_tx(tmpctx, dstate->topology, &peer->anchor.txid);
-	channel_id.blocknum = loc->blkheight;
-	channel_id.txnum = loc->index;
-	channel_id.outnum = peer->anchor.index;
+	short_channel_id.blocknum = loc->blkheight;
+	short_channel_id.txnum = loc->index;
+	short_channel_id.outnum = peer->anchor.index;
 
 	/* Avoid triggering memcheck */
 	memset(&signature, 0, sizeof(signature));
 
-	serialized = towire_channel_update(tmpctx, &signature, &channel_id,
+	serialized = towire_channel_update(tmpctx, &signature, &short_channel_id,
 					   timestamp,
 					   pubkey_cmp(&dstate->id, peer->id) > 0,
 					   dstate->config.min_htlc_expiry,
@@ -41,7 +41,7 @@ static void broadcast_channel_update(struct lightningd_state *dstate, struct pee
 					   dstate->config.fee_per_satoshi);
 	privkey_sign(dstate, serialized + 66, tal_count(serialized) - 66,
 		     &signature);
-	serialized = towire_channel_update(tmpctx, &signature, &channel_id,
+	serialized = towire_channel_update(tmpctx, &signature, &short_channel_id,
 					   timestamp,
 					   pubkey_cmp(&dstate->id, peer->id) > 0,
 					   dstate->config.min_htlc_expiry,
@@ -49,7 +49,7 @@ static void broadcast_channel_update(struct lightningd_state *dstate, struct pee
 					   dstate->config.fee_base,
 					   dstate->config.fee_per_satoshi);
 	u8 *tag = tal_arr(tmpctx, u8, 0);
-	towire_channel_id(&tag, &channel_id);
+	towire_short_channel_id(&tag, &short_channel_id);
 	queue_broadcast(dstate->rstate->broadcasts, WIRE_CHANNEL_UPDATE, tag, serialized);
 	tal_free(tmpctx);
 }
@@ -96,7 +96,7 @@ static void broadcast_node_announcement(struct lightningd_state *dstate)
 static void broadcast_channel_announcement(struct lightningd_state *dstate, struct peer *peer)
 {
 	struct txlocator *loc;
-	struct channel_id channel_id;
+	struct short_channel_id short_channel_id;
 	secp256k1_ecdsa_signature node_signature[2];
 	secp256k1_ecdsa_signature bitcoin_signature[2];
 	const struct pubkey *node_id[2];
@@ -108,9 +108,9 @@ static void broadcast_channel_announcement(struct lightningd_state *dstate, stru
 
 	loc = locate_tx(tmpctx, dstate->topology, &peer->anchor.txid);
 
-	channel_id.blocknum = loc->blkheight;
-	channel_id.txnum = loc->index;
-	channel_id.outnum = peer->anchor.index;
+	short_channel_id.blocknum = loc->blkheight;
+	short_channel_id.txnum = loc->index;
+	short_channel_id.outnum = peer->anchor.index;
 
 	/* Set all sigs to zero */
 	memset(node_signature, 0, sizeof(node_signature));
@@ -147,7 +147,7 @@ static void broadcast_channel_announcement(struct lightningd_state *dstate, stru
 						 &node_signature[1],
 						 &bitcoin_signature[0],
 						 &bitcoin_signature[1],
-						 &channel_id,
+						 &short_channel_id,
 						 node_id[0],
 						 node_id[1],
 						 bitcoin_key[0],
@@ -159,14 +159,14 @@ static void broadcast_channel_announcement(struct lightningd_state *dstate, stru
 						 &node_signature[1],
 						 &bitcoin_signature[0],
 						 &bitcoin_signature[1],
-						 &channel_id,
+						 &short_channel_id,
 						 node_id[0],
 						 node_id[1],
 						 bitcoin_key[0],
 						 bitcoin_key[1],
 						 NULL);
 	u8 *tag = tal_arr(tmpctx, u8, 0);
-	towire_channel_id(&tag, &channel_id);
+	towire_short_channel_id(&tag, &short_channel_id);
 	queue_broadcast(dstate->rstate->broadcasts, WIRE_CHANNEL_ANNOUNCEMENT,
 			tag, serialized);
 	tal_free(tmpctx);

daemon/routing.c

@@ -147,8 +147,8 @@ struct node_connection * get_connection(struct routing_state *rstate,
 	return NULL;
 }
 
-struct node_connection *get_connection_by_cid(const struct routing_state *rstate,
-					      const struct channel_id *chanid,
+struct node_connection *get_connection_by_scid(const struct routing_state *rstate,
+					      const struct short_channel_id *schanid,
 					      const u8 direction)
 {
 	struct node *n;
@@ -162,7 +162,7 @@ struct node_connection *get_connection_by_cid(const struct routing_state *rstate
 	        num_conn = tal_count(n->out);
 		for (i = 0; i < num_conn; i++){
 			c = n->out[i];
-			if (structeq(&c->channel_id, chanid) &&
+			if (structeq(&c->short_channel_id, schanid) &&
 			    (c->flags&0x1) == direction)
 			    return c;
 		}
@@ -224,13 +224,13 @@ get_or_make_connection(struct routing_state *rstate,
 struct node_connection *half_add_connection(struct routing_state *rstate,
 					    const struct pubkey *from,
 					    const struct pubkey *to,
-					    const struct channel_id *chanid,
+					    const struct short_channel_id *schanid,
 					    const u16 flags
 	)
 {
 	struct node_connection *nc;
 	nc = get_or_make_connection(rstate, from, to);
-	memcpy(&nc->channel_id, chanid, sizeof(nc->channel_id));
+	nc->short_channel_id = *schanid;
 	nc->active = false;
 	nc->last_timestamp = 0;
 	nc->flags = flags;
@@ -257,7 +257,7 @@ struct node_connection *add_connection(struct routing_state *rstate,
 	c->min_blocks = min_blocks;
 	c->active = true;
 	c->last_timestamp = 0;
-	memset(&c->channel_id, 0, sizeof(c->channel_id));
+	memset(&c->short_channel_id, 0, sizeof(c->short_channel_id));
 	c->flags = pubkey_cmp(from, to) > 0;
 	return c;
 }
@@ -514,20 +514,21 @@ bool add_channel_direction(struct routing_state *rstate,
 			   const struct pubkey *from,
 			   const struct pubkey *to,
 			   const int direction,
-			   const struct channel_id *channel_id,
+			   const struct short_channel_id *short_channel_id,
 			   const u8 *announcement)
 {
 	struct node_connection *c = get_connection(rstate, from, to);
 	if (c){
 		/* Do not clobber connections added otherwise */
-		memcpy(&c->channel_id, channel_id, sizeof(c->channel_id));
+		memcpy(&c->short_channel_id, short_channel_id,
+		       sizeof(c->short_channel_id));
 		c->flags = direction;
 		return false;
-	}else if(get_connection_by_cid(rstate, channel_id, direction)) {
+	}else if(get_connection_by_scid(rstate, short_channel_id, direction)) {
 		return false;
 	}
 
-	c = half_add_connection(rstate, from, to, channel_id, direction);
+	c = half_add_connection(rstate, from, to, short_channel_id, direction);
 
 	/* Remember the announcement so we can forward it to new peers */
 	tal_free(c->channel_announcement);
@@ -647,7 +648,7 @@ void handle_channel_announcement(
 	bool forward = false;
 	secp256k1_ecdsa_signature node_signature_1;
 	secp256k1_ecdsa_signature node_signature_2;
-	struct channel_id channel_id;
+	struct short_channel_id short_channel_id;
 	secp256k1_ecdsa_signature bitcoin_signature_1;
 	secp256k1_ecdsa_signature bitcoin_signature_2;
 	struct pubkey node_id_1;
@@ -662,7 +663,7 @@ void handle_channel_announcement(
 					   &node_signature_1, &node_signature_2,
 					   &bitcoin_signature_1,
 					   &bitcoin_signature_2,
-					   &channel_id,
+					   &short_channel_id,
 					   &node_id_1, &node_id_2,
 					   &bitcoin_key_1, &bitcoin_key_2,
 					   &features)) {
@@ -676,16 +677,16 @@ void handle_channel_announcement(
 
 	log_debug(rstate->base_log,
 		  "Received channel_announcement for channel %d:%d:%d",
-		  channel_id.blocknum,
-		  channel_id.txnum,
-		  channel_id.outnum
+		  short_channel_id.blocknum,
+		  short_channel_id.txnum,
+		  short_channel_id.outnum
 		);
 
 	forward |= add_channel_direction(rstate, &node_id_1,
-					 &node_id_2, 0, &channel_id,
+					 &node_id_2, 0, &short_channel_id,
 					 serialized);
 	forward |= add_channel_direction(rstate, &node_id_2,
-					 &node_id_1, 1, &channel_id,
+					 &node_id_1, 1, &short_channel_id,
 					 serialized);
 	if (!forward){
 		log_debug(rstate->base_log, "Not forwarding channel_announcement");
@@ -694,7 +695,7 @@ void handle_channel_announcement(
 	}
 
 	u8 *tag = tal_arr(tmpctx, u8, 0);
-	towire_channel_id(&tag, &channel_id);
+	towire_short_channel_id(&tag, &short_channel_id);
 	queue_broadcast(rstate->broadcasts, WIRE_CHANNEL_ANNOUNCEMENT,
 			tag, serialized);
 
@@ -706,7 +707,7 @@ void handle_channel_update(struct routing_state *rstate, const u8 *update, size_
 	u8 *serialized;
 	struct node_connection *c;
 	secp256k1_ecdsa_signature signature;
-	struct channel_id channel_id;
+	struct short_channel_id short_channel_id;
 	u32 timestamp;
 	u16 flags;
 	u16 expiry;
@@ -716,7 +717,7 @@ void handle_channel_update(struct routing_state *rstate, const u8 *update, size_
 	const tal_t *tmpctx = tal_tmpctx(rstate);
 
 	serialized = tal_dup_arr(tmpctx, u8, update, len, 0);
-	if (!fromwire_channel_update(serialized, NULL, &signature, &channel_id,
+	if (!fromwire_channel_update(serialized, NULL, &signature, &short_channel_id,
 				     &timestamp, &flags, &expiry,
 				     &htlc_minimum_msat, &fee_base_msat,
 				     &fee_proportional_millionths)) {
@@ -726,19 +727,19 @@ void handle_channel_update(struct routing_state *rstate, const u8 *update, size_
 
 
 	log_debug(rstate->base_log, "Received channel_update for channel %d:%d:%d(%d)",
-		  channel_id.blocknum,
-		  channel_id.txnum,
-		  channel_id.outnum,
+		  short_channel_id.blocknum,
+		  short_channel_id.txnum,
+		  short_channel_id.outnum,
 		  flags & 0x01
 		);
 
-	c = get_connection_by_cid(rstate, &channel_id, flags & 0x1);
+	c = get_connection_by_scid(rstate, &short_channel_id, flags & 0x1);
 
 	if (!c) {
 		log_debug(rstate->base_log, "Ignoring update for unknown channel %d:%d:%d",
-			  channel_id.blocknum,
-			  channel_id.txnum,
-			  channel_id.outnum
+			  short_channel_id.blocknum,
+			  short_channel_id.txnum,
+			  short_channel_id.outnum
 			);
 		tal_free(tmpctx);
 		return;
@@ -756,14 +757,14 @@ void handle_channel_update(struct routing_state *rstate, const u8 *update, size_
 	c->proportional_fee = fee_proportional_millionths;
 	c->active = true;
 	log_debug(rstate->base_log, "Channel %d:%d:%d(%d) was updated.",
-		  channel_id.blocknum,
-		  channel_id.txnum,
-		  channel_id.outnum,
+		  short_channel_id.blocknum,
+		  short_channel_id.txnum,
+		  short_channel_id.outnum,
 		  flags
 		);
 
 	u8 *tag = tal_arr(tmpctx, u8, 0);
-	towire_channel_id(&tag, &channel_id);
+	towire_short_channel_id(&tag, &short_channel_id);
 	queue_broadcast(rstate->broadcasts,
 			WIRE_CHANNEL_UPDATE,
 			tag,

daemon/routing.h

@@ -29,7 +29,7 @@ struct node_connection {
 	u32 htlc_minimum_msat;
 
 	/* The channel ID, as determined by the anchor transaction */
-	struct channel_id channel_id;
+	struct short_channel_id short_channel_id;
 
 	/* Flags as specified by the `channel_update`s, among other
 	 * things indicated direction wrt the `channel_id` */
@@ -121,7 +121,7 @@ struct node_connection *add_connection(struct routing_state *rstate,
 struct node_connection *half_add_connection(struct routing_state *rstate,
 					    const struct pubkey *from,
 					    const struct pubkey *to,
-					    const struct channel_id *chanid,
+					    const struct short_channel_id *schanid,
 					    const u16 flags);
 
 /* Get an existing connection between `from` and `to`, NULL if no such
@@ -130,10 +130,10 @@ struct node_connection *get_connection(struct routing_state *rstate,
 				       const struct pubkey *from,
 				       const struct pubkey *to);
 
-/* Given a channel_id, retrieve the matching connection, or NULL if it is
+/* Given a short_channel_id, retrieve the matching connection, or NULL if it is
  * unknown. */
-struct node_connection *get_connection_by_cid(const struct routing_state *rstate,
-					      const struct channel_id *chanid,
+struct node_connection *get_connection_by_scid(const struct routing_state *rstate,
+					       const struct short_channel_id *schanid,
 					      const u8 direction);
 
 void remove_connection(struct routing_state *rstate,
@@ -156,7 +156,7 @@ bool add_channel_direction(struct routing_state *rstate,
 			   const struct pubkey *from,
 			   const struct pubkey *to,
 			   const int direction,
-			   const struct channel_id *channel_id,
+			   const struct short_channel_id *short_channel_id,
 			   const u8 *announcement);
 
 bool read_ip(const tal_t *ctx, const u8 *addresses, char **hostname, int *port);

lightningd/channel.c

@@ -267,7 +267,7 @@ enum channel_add_err channel_add_htlc(struct channel *channel,
 	 *
 	 * 1. type: 128 (`update_add_htlc`)
 	 * 2. data:
-	 *    * [8:channel-id]
+	 *    * [32:channel-id]
 	 *    * [8:id]
 	 *    * [4:amount-msat]
 	 *    * [4:cltv-expiry]

lightningd/channel_config.h

@@ -8,7 +8,7 @@
  *
  * 1. type: 32 (`open_channel`)
  * 2. data:
- *    * [8:temporary-channel-id]
+ *    * [32:temporary-channel-id]
  *    * [8:funding-satoshis]
  *    * [8:push-msat]
  *    * [8:dust-limit-satoshis]
@@ -21,7 +21,7 @@
  *...
  * 1. type: 33 (`accept_channel`)
  * 2. data:
- *    * [8:temporary-channel-id]
+ *    * [32:temporary-channel-id]
  *    * [8:dust-limit-satoshis]
  *    * [8:max-htlc-value-in-flight-msat]
  *    * [8:channel-reserve-satoshis]

lightningd/cryptomsg.c

@@ -18,7 +18,7 @@ static void hkdf_two_keys(struct sha256 *out1, struct sha256 *out2,
 {
 	/* BOLT #8:
 	 *
-	 *   * `HKDF(salt,ikm)`: a function is defined in [5](#reference-5),
+	 *   * `HKDF(salt,ikm)`: a function is defined in [3](#reference-3),
 	 *      evaluated with a zero-length `info` field.
 	 *      * All invocations of the `HKDF` implicitly return `64-bytes`
 	 *        of cryptographic randomness using the extract-and-expand

lightningd/handshake/handshake.c

@@ -119,7 +119,7 @@ static void hkdf_two_keys(struct secret *out1, struct secret *out2,
 {
 	/* BOLT #8:
 	 *
-	 *   * `HKDF(salt,ikm)`: a function is defined in [5](#reference-5),
+	 *   * `HKDF(salt,ikm)`: a function is defined in [3](#reference-3),
 	 *      evaluated with a zero-length `info` field.
 	 *      * All invocations of the `HKDF` implicitly return `64-bytes`
 	 *        of cryptographic randomness using the extract-and-expand

lightningd/opening/opening.c

@@ -2,6 +2,7 @@
 #include <bitcoin/privkey.h>
 #include <bitcoin/script.h>
 #include <ccan/breakpoint/breakpoint.h>
+#include <ccan/build_assert/build_assert.h>
 #include <ccan/crypto/hkdf_sha256/hkdf_sha256.h>
 #include <ccan/crypto/shachain/shachain.h>
 #include <ccan/fdpass/fdpass.h>
@@ -53,7 +54,7 @@ struct state {
 	u64 funding_satoshis, push_msat;
 	u32 feerate_per_kw;
 	struct sha256_double funding_txid;
-	u8 funding_txout;
+	u16 funding_txout;
 
 	/* Secret keys and basepoint secrets. */
 	struct secrets our_secrets;
@@ -257,10 +258,39 @@ static void set_reserve(u64 *reserve, u64 funding)
 	*reserve = (funding + 99) / 100;
 }
 
+/* BOLT #2:
+ *
+ * This message introduces the `channel-id` which identifies , which is
+ * derived from the funding transaction by combining the `funding-txid` and
+ * the `funding-output-index` using big-endian exclusive-OR
+ * (ie. `funding-output-index` alters the last two bytes).
+ */
+static void derive_channel_id(struct channel_id *channel_id,
+			      struct sha256_double *txid, u16 txout)
+{
+	BUILD_ASSERT(sizeof(*channel_id) == sizeof(*txid));
+	memcpy(channel_id, txid, sizeof(*channel_id));
+	channel_id->id[sizeof(*channel_id)-2] ^= txout >> 8;
+	channel_id->id[sizeof(*channel_id)-1] ^= txout;
+}
+
+/* BOLT #2:
+ *
+ * A sending node MUST ensure `temporary-channel-id` is unique from any other
+ * channel id with the same peer.
+ */
+static void temporary_channel_id(struct channel_id *channel_id)
+{
+	size_t i;
+
+	for (i = 0; i < sizeof(*channel_id); i++)
+		channel_id->id[i] = pseudorand(256);
+}
+
 static u8 *open_channel(struct state *state, const struct points *ours,
 			u32 max_minimum_depth)
 {
-	struct channel_id tmpid, tmpid2;
+	struct channel_id channel_id, id_in;
 	u8 *msg;
 	struct bitcoin_tx *tx;
 	struct points theirs;
@@ -269,14 +299,7 @@ static u8 *open_channel(struct state *state, const struct points *ours,
 	set_reserve(&state->localconf.channel_reserve_satoshis,
 		    state->funding_satoshis);
 
-	/* BOLT #2:
-	 *
-	 * A sending node MUST set the most significant bit in
-	 * `temporary-channel-id`, and MUST ensure it is unique from any other
-	 * channel id with the same peer.
-	 */
-	/* We don't support more than one channel, so this is easy. */
-	memset(&tmpid, 0xFF, sizeof(tmpid));
+	temporary_channel_id(&channel_id);
 
 	/* BOLT #2:
 	 *
@@ -295,7 +318,7 @@ static u8 *open_channel(struct state *state, const struct points *ours,
 			      "push-msat must be < %"PRIu64,
 			      1000 * state->funding_satoshis);
 
-	msg = towire_open_channel(state, &tmpid,
+	msg = towire_open_channel(state, &channel_id,
 				  state->funding_satoshis, state->push_msat,
 				  state->localconf.dust_limit_satoshis,
 				  state->localconf.max_htlc_value_in_flight_msat,
@@ -327,7 +350,7 @@ static u8 *open_channel(struct state *state, const struct points *ours,
 	 * `delayed-payment-basepoint` are not valid DER-encoded compressed
 	 * secp256k1 pubkeys.
 	 */
-	if (!fromwire_accept_channel(msg, NULL, &tmpid2,
+	if (!fromwire_accept_channel(msg, NULL, &id_in,
 				     &state->remoteconf->dust_limit_satoshis,
 				     &state->remoteconf
 					->max_htlc_value_in_flight_msat,
@@ -349,11 +372,11 @@ static u8 *open_channel(struct state *state, const struct points *ours,
 	 *
 	 * The `temporary-channel-id` MUST be the same as the
 	 * `temporary-channel-id` in the `open_channel` message. */
-	if (!structeq(&tmpid, &tmpid2))
+	if (!structeq(&id_in, &channel_id))
 		peer_failed(PEER_FD, &state->cs, NULL, WIRE_OPENING_PEER_READ_FAILED,
 			      "accept_channel ids don't match: sent %s got %s",
-			      type_to_string(msg, struct channel_id, &tmpid),
-			      type_to_string(msg, struct channel_id, &tmpid2));
+			      type_to_string(msg, struct channel_id, &id_in),
+			      type_to_string(msg, struct channel_id, &channel_id));
 
 	/* BOLT #2:
 	 *
@@ -421,7 +444,7 @@ static u8 *open_channel(struct state *state, const struct points *ours,
 		     type_to_string(trc, struct bitcoin_tx, tx),
 		     type_to_string(trc, struct pubkey, &ours->funding_pubkey));
 
-	msg = towire_funding_created(state, &tmpid,
+	msg = towire_funding_created(state, &channel_id,
 				     &state->funding_txid.sha,
 				     state->funding_txout,
 				     &sig);
@@ -442,15 +465,27 @@ static u8 *open_channel(struct state *state, const struct points *ours,
 		peer_failed(PEER_FD, &state->cs, NULL, WIRE_OPENING_PEER_READ_FAILED,
 			      "Reading funding_signed");
 
-	if (!fromwire_funding_signed(msg, NULL, &tmpid2, &sig))
+	if (!fromwire_funding_signed(msg, NULL, &id_in, &sig))
 		peer_failed(PEER_FD, &state->cs, NULL, WIRE_OPENING_PEER_READ_FAILED,
 			    "Parsing funding_signed (%s)",
 			    wire_type_name(fromwire_peektype(msg)));
-	if (!structeq(&tmpid, &tmpid2))
+
+	/* BOLT #2:
+	 *
+	 * This message introduces the `channel-id` which identifies , which
+	 * is derived from the funding transaction by combining the
+	 * `funding-txid` and the `funding-output-index` using big-endian
+	 * exclusive-OR (ie. `funding-output-index` alters the last two
+	 * bytes).
+	 */
+	derive_channel_id(&channel_id,
+			  &state->funding_txid, state->funding_txout);
+
+	if (!structeq(&id_in, &channel_id))
 		peer_failed(PEER_FD, &state->cs, NULL, WIRE_OPENING_PEER_READ_FAILED,
-			      "funding_signed ids don't match: sent %s got %s",
-			      type_to_string(msg, struct channel_id, &tmpid),
-			      type_to_string(msg, struct channel_id, &tmpid2));
+			      "funding_signed ids don't match: expceted %s got %s",
+			      type_to_string(msg, struct channel_id, &channel_id),
+			      type_to_string(msg, struct channel_id, &id_in));
 
 	/* BOLT #2:
 	 *
@@ -489,7 +524,7 @@ static u8 *open_channel(struct state *state, const struct points *ours,
 static u8 *recv_channel(struct state *state, const struct points *ours,
 			u32 min_feerate, u32 max_feerate, const u8 *peer_msg)
 {
-	struct channel_id tmpid, tmpid2;
+	struct channel_id id_in, channel_id;
 	struct points theirs;
 	secp256k1_ecdsa_signature theirsig, sig;
 	struct bitcoin_tx *tx;
@@ -504,7 +539,7 @@ static u8 *recv_channel(struct state *state, const struct points *ours,
 	 * `delayed-payment-basepoint` are not valid DER-encoded compressed
 	 * secp256k1 pubkeys.
 	 */
-	if (!fromwire_open_channel(peer_msg, NULL, &tmpid,
+	if (!fromwire_open_channel(peer_msg, NULL, &channel_id,
 				   &state->funding_satoshis, &state->push_msat,
 				   &state->remoteconf->dust_limit_satoshis,
 				   &state->remoteconf->max_htlc_value_in_flight_msat,
@@ -561,7 +596,7 @@ static u8 *recv_channel(struct state *state, const struct points *ours,
 		    state->funding_satoshis);
 	check_config_bounds(state, state->remoteconf);
 
-	msg = towire_accept_channel(state, &tmpid,
+	msg = towire_accept_channel(state, &channel_id,
 				    state->localconf.dust_limit_satoshis,
 				    state->localconf
 				      .max_htlc_value_in_flight_msat,
@@ -585,7 +620,7 @@ static u8 *recv_channel(struct state *state, const struct points *ours,
 		peer_failed(PEER_FD, &state->cs, NULL, WIRE_OPENING_PEER_READ_FAILED,
 			      "Reading funding_created");
 
-	if (!fromwire_funding_created(msg, NULL, &tmpid2,
+	if (!fromwire_funding_created(msg, NULL, &id_in,
 				      &state->funding_txid.sha,
 				      &state->funding_txout,
 				      &theirsig))
@@ -596,11 +631,11 @@ static u8 *recv_channel(struct state *state, const struct points *ours,
 	 *
 	 * The sender MUST set `temporary-channel-id` the same as the
 	 * `temporary-channel-id` in the `open_channel` message. */
-	if (!structeq(&tmpid, &tmpid2))
+	if (!structeq(&id_in, &channel_id))
 		peer_failed(PEER_FD, &state->cs, NULL, WIRE_OPENING_PEER_READ_FAILED,
 			    "funding_created ids don't match: sent %s got %s",
-			      type_to_string(msg, struct channel_id, &tmpid),
-			      type_to_string(msg, struct channel_id, &tmpid2));
+			    type_to_string(msg, struct channel_id, &channel_id),
+			    type_to_string(msg, struct channel_id, &id_in));
 
 	state->channel = new_channel(state,
 				      &state->funding_txid,
@@ -638,6 +673,17 @@ static u8 *recv_channel(struct state *state, const struct points *ours,
 			      type_to_string(trc, struct pubkey,
 					     &theirs.funding_pubkey));
 
+	/* BOLT #2:
+	 *
+	 * This message introduces the `channel-id` which identifies , which
+	 * is derived from the funding transaction by combining the
+	 * `funding-txid` and the `funding-output-index` using big-endian
+	 * exclusive-OR (ie. `funding-output-index` alters the last two
+	 * bytes).
+	 */
+	derive_channel_id(&channel_id,
+			  &state->funding_txid, state->funding_txout);
+
 	/* BOLT #2:
 	 *
 	 * ### The `funding_signed` message
@@ -652,7 +698,7 @@ static u8 *recv_channel(struct state *state, const struct points *ours,
 				 &ours->funding_pubkey, &theirs.funding_pubkey,
 				 tx);
 
-	msg = towire_funding_signed(state, &tmpid, &sig);
+	msg = towire_funding_signed(state, &channel_id, &sig);
 	if (!sync_crypto_write(&state->cs, PEER_FD, msg))
 		peer_failed(PEER_FD, &state->cs, NULL, WIRE_OPENING_PEER_WRITE_FAILED,
 			      "Writing funding_signed");

lightningd/opening/opening_control_wire.csv

@@ -25,7 +25,7 @@ opening_open_resp,0,remote_fundingkey,33
 # Now we give the funding txid and outnum.
 opening_open_funding,2
 opening_open_funding,0,txid,32,struct sha256_double
-opening_open_funding,32,txout,1,u8
+opening_open_funding,32,txout,2,u16
 
 # This gives their sig, means we can broadcast tx: we're done.
 opening_open_funding_resp,102
@@ -47,7 +47,7 @@ opening_accept,10,msg,len,u8
 # This gives the txid of their funding tx: we're done.
 opening_accept_resp,103
 opening_accept_resp,0,funding_txid,32,struct sha256_double
-opening_accept_resp,32,funding_txout,1,u8
+opening_accept_resp,32,funding_txout,2,u16
 opening_accept_resp,33,their_config,36,struct channel_config
 opening_accept_resp,69,first_commit_sig,64,secp256k1_ecdsa_signature
 opening_accept_resp,133,crypto_state,144,struct crypto_state

lightningd/peer_failed.c

@@ -19,12 +19,11 @@ void peer_failed(int peer_fd, struct crypto_state *cs,
 
 	/* BOLT #1:
 	 *
-	 * A node sending `error` MUST fail the channel referred to by the
-	 * `channel-id`, or if `channel-id` is `0xFFFFFFFFFFFFFFFF` it MUST
-	 * fail all channels and MUST close the connection.
+	 * The channel is referred to by `channel-id` unless `channel-id` is
+	 * zero (ie. all bytes zero), in which case it refers to all channels.
 	 */
 	if (!channel_id) {
-		memset(&all_channels, 0xFF, sizeof(all_channels));
+		memset(&all_channels, 0, sizeof(all_channels));
 		channel_id = &all_channels;
 	}
 

tools/generate-wire.py

@@ -21,8 +21,10 @@ class FieldType(object):
     def _typesize(typename):
         if typename == 'pad':
             return 1
-        elif typename == 'struct channel_id':
+        elif typename == 'struct short_channel_id':
             return 8
+        elif typename == 'struct channel_id':
+            return 32
         elif typename == 'struct ipv6':
             return 16
         elif typename == 'secp256k1_ecdsa_signature':
@@ -104,6 +106,9 @@ class Field(object):
         if fieldname.startswith('pad'):
             return FieldType('pad')
 
+        if fieldname.endswith('short_channel_id'):
+            return FieldType('struct short_channel_id')
+
         if fieldname.endswith('channel_id'):
             return FieldType('struct channel_id')
 

type_to_string.h

@@ -20,6 +20,7 @@ union printable_types {
 	const struct netaddr *netaddr;
 	const secp256k1_pubkey *secp256k1_pubkey;
 	const struct channel_id *channel_id;
+	const struct short_channel_id *short_channel_id;
 	const struct privkey *privkey;
 	const secp256k1_ecdsa_signature *secp256k1_ecdsa_signature;
 	const struct channel *channel;

wire/fromwire.c

@@ -121,16 +121,22 @@ void fromwire_secp256k1_ecdsa_signature(const u8 **cursor,
 
 void fromwire_channel_id(const u8 **cursor, size_t *max,
 			 struct channel_id *channel_id)
+{
+	fromwire(cursor, max, channel_id, sizeof(*channel_id));
+}
+
+void fromwire_short_channel_id(const u8 **cursor, size_t *max,
+			       struct short_channel_id *short_channel_id)
 {
 	be32 txnum = 0;
 	u8 outnum;
 
-	channel_id->blocknum = fromwire_u32(cursor, max);
+	short_channel_id->blocknum = fromwire_u32(cursor, max);
 	/* Pulling 3 bytes off wire is tricky; they're big-endian. */
 	fromwire(cursor, max, (char *)&txnum + 1, 3);
-	channel_id->txnum = be32_to_cpu(txnum);
+	short_channel_id->txnum = be32_to_cpu(txnum);
 	fromwire(cursor, max, &outnum, 1);
-	channel_id->outnum = outnum;
+	short_channel_id->outnum = outnum;
 }
 
 void fromwire_sha256(const u8 **cursor, size_t *max, struct sha256 *sha256)
@@ -200,8 +206,11 @@ void fromwire_sha256_double_array(const u8 **cursor, size_t *max,
 	for (i = 0; i < num; i++)
 		fromwire_sha256_double(cursor, max, arr + i);
 }
-static char *fmt_channel_id(const tal_t *ctx, const struct channel_id *id)
+
+static char *fmt_short_channel_id(const tal_t *ctx,
+				  const struct short_channel_id *id)
 {
 	return tal_fmt(ctx, "%u/%u/%u", id->blocknum, id->txnum, id->outnum);
 }
-REGISTER_TYPE_TO_STRING(channel_id, fmt_channel_id);
+REGISTER_TYPE_TO_STRING(short_channel_id, fmt_short_channel_id);
+REGISTER_TYPE_TO_HEXSTR(channel_id);

wire/gen_peer_wire_csv

@@ -4,105 +4,105 @@ init,2,globalfeatures,gflen
 init,2+gflen,lflen,2
 init,4+gflen,localfeatures,lflen
 error,17
-error,0,channel-id,8
-error,8,len,2
-error,10,data,len
+error,0,channel-id,32
+error,32,len,2
+error,34,data,len
 open_channel,32
-open_channel,0,temporary-channel-id,8
-open_channel,8,funding-satoshis,8
-open_channel,16,push-msat,8
-open_channel,24,dust-limit-satoshis,8
-open_channel,32,max-htlc-value-in-flight-msat,8
-open_channel,40,channel-reserve-satoshis,8
-open_channel,48,htlc-minimum-msat,4
-open_channel,52,feerate-per-kw,4
-open_channel,56,to-self-delay,2
-open_channel,58,max-accepted-htlcs,2
-open_channel,60,funding-pubkey,33
-open_channel,93,revocation-basepoint,33
-open_channel,126,payment-basepoint,33
-open_channel,159,delayed-payment-basepoint,33
-open_channel,192,first-per-commitment-point,33
+open_channel,0,temporary-channel-id,32
+open_channel,32,funding-satoshis,8
+open_channel,40,push-msat,8
+open_channel,48,dust-limit-satoshis,8
+open_channel,56,max-htlc-value-in-flight-msat,8
+open_channel,64,channel-reserve-satoshis,8
+open_channel,72,htlc-minimum-msat,4
+open_channel,76,feerate-per-kw,4
+open_channel,80,to-self-delay,2
+open_channel,82,max-accepted-htlcs,2
+open_channel,84,funding-pubkey,33
+open_channel,117,revocation-basepoint,33
+open_channel,150,payment-basepoint,33
+open_channel,183,delayed-payment-basepoint,33
+open_channel,216,first-per-commitment-point,33
 accept_channel,33
-accept_channel,0,temporary-channel-id,8
-accept_channel,8,dust-limit-satoshis,8
-accept_channel,16,max-htlc-value-in-flight-msat,8
-accept_channel,24,channel-reserve-satoshis,8
-accept_channel,32,minimum-depth,4
-accept_channel,36,htlc-minimum-msat,4
-accept_channel,40,to-self-delay,2
-accept_channel,42,max-accepted-htlcs,2
-accept_channel,44,funding-pubkey,33
-accept_channel,77,revocation-basepoint,33
-accept_channel,110,payment-basepoint,33
-accept_channel,143,delayed-payment-basepoint,33
-accept_channel,176,first-per-commitment-point,33
+accept_channel,0,temporary-channel-id,32
+accept_channel,32,dust-limit-satoshis,8
+accept_channel,40,max-htlc-value-in-flight-msat,8
+accept_channel,48,channel-reserve-satoshis,8
+accept_channel,56,minimum-depth,4
+accept_channel,60,htlc-minimum-msat,4
+accept_channel,64,to-self-delay,2
+accept_channel,66,max-accepted-htlcs,2
+accept_channel,68,funding-pubkey,33
+accept_channel,101,revocation-basepoint,33
+accept_channel,134,payment-basepoint,33
+accept_channel,167,delayed-payment-basepoint,33
+accept_channel,200,first-per-commitment-point,33
 funding_created,34
-funding_created,0,temporary-channel-id,8
-funding_created,8,txid,32
-funding_created,40,output-index,1
-funding_created,41,signature,64
+funding_created,0,temporary-channel-id,32
+funding_created,32,funding-txid,32
+funding_created,64,funding-output-index,2
+funding_created,66,signature,64
 funding_signed,35
-funding_signed,0,temporary-channel-id,8
-funding_signed,8,signature,64
+funding_signed,0,channel-id,32
+funding_signed,32,signature,64
 funding_locked,36
-funding_locked,0,temporary-channel-id,8
-funding_locked,8,channel-id,8
-funding_locked,16,next-per-commitment-point,33
+funding_locked,0,channel-id,32
+funding_locked,32,next-per-commitment-point,33
 shutdown,38
-shutdown,0,channel-id,8
-shutdown,8,len,2
-shutdown,10,scriptpubkey,len
+shutdown,0,channel-id,32
+shutdown,32,len,2
+shutdown,34,scriptpubkey,len
 closing_signed,39
-closing_signed,0,channel-id,8
-closing_signed,8,fee-satoshis,8
-closing_signed,16,signature,64
+closing_signed,0,channel-id,32
+closing_signed,32,fee-satoshis,8
+closing_signed,40,signature,64
 update_add_htlc,128
-update_add_htlc,0,channel-id,8
-update_add_htlc,8,id,8
-update_add_htlc,16,amount-msat,4
-update_add_htlc,20,cltv-expiry,4
-update_add_htlc,24,payment-hash,32
-update_add_htlc,56,onion-routing-packet,1254
+update_add_htlc,0,channel-id,32
+update_add_htlc,32,id,8
+update_add_htlc,40,amount-msat,4
+update_add_htlc,44,cltv-expiry,4
+update_add_htlc,48,payment-hash,32
+update_add_htlc,80,onion-routing-packet,1254
 update_fulfill_htlc,130
-update_fulfill_htlc,0,channel-id,8
-update_fulfill_htlc,8,id,8
-update_fulfill_htlc,16,payment-preimage,32
+update_fulfill_htlc,0,channel-id,32
+update_fulfill_htlc,32,id,8
+update_fulfill_htlc,40,payment-preimage,32
 update_fail_htlc,131
-update_fail_htlc,0,channel-id,8
-update_fail_htlc,8,id,8
-update_fail_htlc,16,len,2
-update_fail_htlc,18,reason,len
+update_fail_htlc,0,channel-id,32
+update_fail_htlc,32,id,8
+update_fail_htlc,40,len,2
+update_fail_htlc,42,reason,len
 update_fail_malformed_htlc,135
-update_fail_malformed_htlc,0,channel-id,8
-update_fail_malformed_htlc,8,id,8
-update_fail_malformed_htlc,16,sha256-of-onion,32
-update_fail_malformed_htlc,48,failure-code,2
+update_fail_malformed_htlc,0,channel-id,32
+update_fail_malformed_htlc,32,id,8
+update_fail_malformed_htlc,40,sha256-of-onion,32
+update_fail_malformed_htlc,72,failure-code,2
 commit_sig,132
-commit_sig,0,channel-id,8
-commit_sig,8,signature,64
-commit_sig,72,num-htlcs,2
-commit_sig,74,htlc-signature,num-htlcs*64
+commit_sig,0,channel-id,32
+commit_sig,32,signature,64
+commit_sig,96,num-htlcs,2
+commit_sig,98,htlc-signature,num-htlcs*64
 revoke_and_ack,133
-revoke_and_ack,0,channel-id,8
-revoke_and_ack,8,per-commitment-secret,32
-revoke_and_ack,40,next-per-commitment-point,33
-revoke_and_ack,73,padding,1
-revoke_and_ack,74,num-htlc-timeouts,2
-revoke_and_ack,76,htlc-timeout-signature,num-htlc-timeouts*64
+revoke_and_ack,0,channel-id,32
+revoke_and_ack,32,per-commitment-secret,32
+revoke_and_ack,64,next-per-commitment-point,33
+revoke_and_ack,97,padding,1
+revoke_and_ack,98,num-htlc-timeouts,2
+revoke_and_ack,100,htlc-timeout-signature,num-htlc-timeouts*64
 update_fee,134
-update_fee,0,channel-id,8
-update_fee,8,feerate-per-kw,4
+update_fee,0,channel-id,32
+update_fee,32,feerate-per-kw,4
 announcement_signatures,259
-announcement_signatures,0,channel-id,8
-announcement_signatures,8,node-signature,64
-announcement_signatures,72,bitcoin-signature,64
+announcement_signatures,0,channel-id,32
+announcement_signatures,32,short-channel-id,8
+announcement_signatures,40,node-signature,64
+announcement_signatures,104,bitcoin-signature,64
 channel_announcement,256
 channel_announcement,0,node-signature-1,64
 channel_announcement,64,node-signature-2,64
 channel_announcement,128,bitcoin-signature-1,64
 channel_announcement,192,bitcoin-signature-2,64
-channel_announcement,256,channel-id,8
+channel_announcement,256,short-channel-id,8
 channel_announcement,264,node-id-1,33
 channel_announcement,297,node-id-2,33
 channel_announcement,330,bitcoin-key-1,33
@@ -121,7 +121,7 @@ node_announcement,138+flen,addrlen,2
 node_announcement,140+flen,addresses,addrlen
 channel_update,258
 channel_update,0,signature,64
-channel_update,64,channel-id,8
+channel_update,64,short-channel-id,8
 channel_update,72,timestamp,4
 channel_update,76,flags,2
 channel_update,78,cltv-expiry-delta,2

wire/test/run-peer-wire.c

@@ -91,7 +91,7 @@ struct msg_closing_signed {
 struct msg_funding_created {
 	struct channel_id temporary_channel_id;
 	struct sha256 txid;
-	u8 output_index;
+	u16 output_index;
 	secp256k1_ecdsa_signature signature;
 };
 struct msg_accept_channel {
@@ -131,7 +131,7 @@ struct msg_revoke_and_ack {
 };
 struct msg_channel_update {
 	secp256k1_ecdsa_signature signature;
-	struct channel_id channel_id;
+	struct short_channel_id short_channel_id;
 	u32 timestamp;
 	u16 flags;
 	u16 expiry;
@@ -140,12 +140,12 @@ struct msg_channel_update {
 	u32 fee_proportional_millionths;
 };
 struct msg_funding_locked {
-	struct channel_id temporary_channel_id;
 	struct channel_id channel_id;
 	struct pubkey next_per_commitment_point;
 };
 struct msg_announcement_signatures {
 	struct channel_id channel_id;
+	struct short_channel_id short_channel_id;
 	secp256k1_ecdsa_signature announcement_node_signature;
 	secp256k1_ecdsa_signature announcement_bitcoin_signature;
 };
@@ -190,7 +190,7 @@ struct msg_channel_announcement {
 	secp256k1_ecdsa_signature node_signature_2;
 	secp256k1_ecdsa_signature bitcoin_signature_1;
 	secp256k1_ecdsa_signature bitcoin_signature_2;
-	struct channel_id channel_id;
+	struct short_channel_id short_channel_id;
 	struct pubkey node_id_1;
 	struct pubkey node_id_2;
 	struct pubkey bitcoin_key_1;
@@ -222,7 +222,7 @@ static void *towire_struct_channel_announcement(const tal_t *ctx,
 					   &s->node_signature_2,
 					   &s->bitcoin_signature_1,
 					   &s->bitcoin_signature_2,
-					   &s->channel_id,
+					   &s->short_channel_id,
 					   &s->node_id_1,
 					   &s->node_id_2,
 					   &s->bitcoin_key_1,
@@ -238,7 +238,7 @@ static struct msg_channel_announcement *fromwire_struct_channel_announcement(con
 					  &s->node_signature_2,
 					  &s->bitcoin_signature_1,
 					  &s->bitcoin_signature_2,
-					  &s->channel_id,
+					  &s->short_channel_id,
 					  &s->node_id_1,
 					  &s->node_id_2,
 					  &s->bitcoin_key_1,
@@ -366,7 +366,7 @@ static void *towire_struct_channel_update(const tal_t *ctx,
 {
 	return towire_channel_update(ctx, 
 				     &s->signature,
-				     &s->channel_id,
+				     &s->short_channel_id,
 				     s->timestamp,
 				     s->flags,
 				     s->expiry,
@@ -381,7 +381,7 @@ static struct msg_channel_update *fromwire_struct_channel_update(const tal_t *ct
 
 	if (fromwire_channel_update(p, plen, 
 				    &s->signature,
-				    &s->channel_id,
+				    &s->short_channel_id,
 				    &s->timestamp,
 				    &s->flags,
 				    &s->expiry,
@@ -396,7 +396,6 @@ static void *towire_struct_funding_locked(const tal_t *ctx,
 						const struct msg_funding_locked *s)
 {
 	return towire_funding_locked(ctx, 
-				     &s->temporary_channel_id,
 				     &s->channel_id,
 				     &s->next_per_commitment_point);
 }
@@ -406,7 +405,6 @@ static struct msg_funding_locked *fromwire_struct_funding_locked(const tal_t *ct
 	struct msg_funding_locked *s = tal(ctx, struct msg_funding_locked);
 
 	if (fromwire_funding_locked(p, plen, 
-				    &s->temporary_channel_id,
 				    &s->channel_id,
 				    &s->next_per_commitment_point))
 		return s;
@@ -418,6 +416,7 @@ static void *towire_struct_announcement_signatures(const tal_t *ctx,
 {
 	return towire_announcement_signatures(ctx, 
 				     &s->channel_id,
+				     &s->short_channel_id,
 				     &s->announcement_node_signature,
 				     &s->announcement_bitcoin_signature);
 }
@@ -428,6 +427,7 @@ static struct msg_announcement_signatures *fromwire_struct_announcement_signatur
 
 	if (fromwire_announcement_signatures(p, plen, 
 				    &s->channel_id,
+				    &s->short_channel_id,
 				    &s->announcement_node_signature,
 				    &s->announcement_bitcoin_signature))
 		return s;

wire/towire.c

@@ -70,10 +70,16 @@ void towire_secp256k1_ecdsa_signature(u8 **pptr,
 
 void towire_channel_id(u8 **pptr, const struct channel_id *channel_id)
 {
-	be32 txnum = cpu_to_be32(channel_id->txnum);
-	u8 outnum = channel_id->outnum;
+	towire(pptr, channel_id, sizeof(*channel_id));
+}
+
+void towire_short_channel_id(u8 **pptr,
+			     const struct short_channel_id *short_channel_id)
+{
+	be32 txnum = cpu_to_be32(short_channel_id->txnum);
+	u8 outnum = short_channel_id->outnum;
 
-	towire_u32(pptr, channel_id->blocknum);
+	towire_u32(pptr, short_channel_id->blocknum);
 	towire(pptr, (char *)&txnum + 1, 3);
 	towire(pptr, &outnum, 1);
 }

wire/wire.h

@@ -9,11 +9,14 @@
 #include <ccan/short_types/short_types.h>
 #include <stdlib.h>
 
-struct channel_id {
+struct short_channel_id {
 	u32 blocknum;
 	u32 txnum : 24;
 	u8 outnum : 8;
 };
+struct channel_id {
+	u8 id[32];
+};
 struct ipv6 {
 	u8 addr[16];
 };
@@ -27,6 +30,8 @@ void towire_privkey(u8 **pptr, const struct privkey *privkey);
 void towire_secp256k1_ecdsa_signature(u8 **pptr,
 			      const secp256k1_ecdsa_signature *signature);
 void towire_channel_id(u8 **pptr, const struct channel_id *channel_id);
+void towire_short_channel_id(u8 **pptr,
+			     const struct short_channel_id *short_channel_id);
 void towire_sha256(u8 **pptr, const struct sha256 *sha256);
 void towire_sha256_double(u8 **pptr, const struct sha256_double *sha256d);
 void towire_ipv6(u8 **pptr, const struct ipv6 *ipv6);
@@ -59,6 +64,8 @@ void fromwire_secp256k1_ecdsa_signature(const u8 **cursor, size_t *max,
 					secp256k1_ecdsa_signature *signature);
 void fromwire_channel_id(const u8 **cursor, size_t *max,
 			 struct channel_id *channel_id);
+void fromwire_short_channel_id(const u8 **cursor, size_t *max,
+			       struct short_channel_id *short_channel_id);
 void fromwire_sha256(const u8 **cursor, size_t *max, struct sha256 *sha256);
 void fromwire_sha256_double(const u8 **cursor, size_t *max,
 			    struct sha256_double *sha256d);