df: rename 'funder' to 'opener'

Previously we've used the term 'funder' to refer to the peer
paying the fees for a transaction; v2 of openchannel will make
this no longer true. Instead we rename this to 'opener', or the
peer sending the 'open_channel' message, since this will be universally
true in a dual-funding world.

Author: niftynei

channeld/channel_wire.csv

@@ -24,7 +24,7 @@ msgdata,channel_init,remote_fundingkey,pubkey,
 msgdata,channel_init,remote_basepoints,basepoints,
 msgdata,channel_init,remote_per_commit,pubkey,
 msgdata,channel_init,old_remote_per_commit,pubkey,
-msgdata,channel_init,funder,enum side,
+msgdata,channel_init,opener,enum side,
 msgdata,channel_init,fee_base,u32,
 msgdata,channel_init,fee_proportional,u32,
 msgdata,channel_init,local_msatoshi,amount_msat,

channeld/channeld.c

@@ -669,10 +669,10 @@ static void handle_peer_feechange(struct peer *peer, const u8 *msg)
 	 *  - if the sender is not responsible for paying the Bitcoin fee:
 	 *    - MUST fail the channel.
 	 */
-	if (peer->channel->funder != REMOTE)
+	if (peer->channel->opener != REMOTE)
 		peer_failed(peer->pps,
 			    &peer->channel_id,
-			    "update_fee from non-funder?");
+			    "update_fee from non-opener?");
 
 	status_debug("update_fee %u, range %u-%u",
 		     feerate, peer->feerate_min, peer->feerate_max);
@@ -975,7 +975,7 @@ static void send_commit(struct peer *peer)
 	}
 
 	/* If we wanted to update fees, do it now. */
-	if (peer->channel->funder == LOCAL) {
+	if (peer->channel->opener == LOCAL) {
 		u32 feerate, max = approx_max_feerate(peer->channel);
 
 		feerate = peer->desired_feerate;
@@ -1240,11 +1240,11 @@ static void handle_peer_commit_sig(struct peer *peer, const u8 *msg)
 	}
 
 	/* We were supposed to check this was affordable as we go. */
-	if (peer->channel->funder == REMOTE) {
+	if (peer->channel->opener == REMOTE) {
 		status_debug("Feerates are %u/%u",
 			     channel_feerate(peer->channel, LOCAL),
 			     channel_feerate(peer->channel, REMOTE));
-		assert(can_funder_afford_feerate(peer->channel,
+		assert(can_opener_afford_feerate(peer->channel,
 						 channel_feerate(peer->channel,
 								 LOCAL)));
 	}
@@ -1432,7 +1432,7 @@ static void handle_peer_revoke_and_ack(struct peer *peer, const u8 *msg)
 	peer->old_remote_per_commit = peer->remote_per_commit;
 	peer->remote_per_commit = next_per_commit;
 	status_debug("revoke_and_ack %s: remote_per_commit = %s, old_remote_per_commit = %s",
-		     side_to_str(peer->channel->funder),
+		     side_to_str(peer->channel->opener),
 		     type_to_string(tmpctx, struct pubkey,
 				    &peer->remote_per_commit),
 		     type_to_string(tmpctx, struct pubkey,
@@ -2107,7 +2107,7 @@ static void resend_commitment(struct peer *peer, const struct changed_htlc *last
 	}
 
 	/* Make sure they have the correct fee. */
-	if (peer->channel->funder == LOCAL) {
+	if (peer->channel->opener == LOCAL) {
 		msg = towire_update_fee(NULL, &peer->channel_id,
 					channel_feerate(peer->channel, REMOTE));
 		sync_crypto_write(peer->pps, take(msg));
@@ -2812,7 +2812,7 @@ static void handle_feerates(struct peer *peer, const u8 *inmsg)
 	 *    sufficient (by a significant margin) for timely processing of the
 	 *     commitment transaction.
 	 */
-	if (peer->channel->funder == LOCAL) {
+	if (peer->channel->opener == LOCAL) {
 		peer->desired_feerate = feerate;
 		/* Don't do this for the first feerate, wait until something else
 		 * happens.  LND seems to get upset in some cases otherwise:
@@ -3067,7 +3067,7 @@ static void init_channel(struct peer *peer)
 	struct pubkey funding_pubkey[NUM_SIDES];
 	struct channel_config conf[NUM_SIDES];
 	struct bitcoin_txid funding_txid;
-	enum side funder;
+	enum side opener;
 	struct existing_htlc **htlcs;
 	bool reconnected;
 	u8 *funding_signed;
@@ -3102,7 +3102,7 @@ static void init_channel(struct peer *peer)
 				   &points[REMOTE],
 				   &peer->remote_per_commit,
 				   &peer->old_remote_per_commit,
-				   &funder,
+				   &opener,
 				   &peer->fee_base,
 				   &peer->fee_per_satoshi,
 				   &local_msat,
@@ -3148,7 +3148,7 @@ static void init_channel(struct peer *peer)
 		     " next_idx_remote = %"PRIu64
 		     " revocations_received = %"PRIu64
 		     " feerates %s range %u-%u",
-		     side_to_str(funder),
+		     side_to_str(opener),
 		     type_to_string(tmpctx, struct pubkey,
 				    &peer->remote_per_commit),
 		     type_to_string(tmpctx, struct pubkey,
@@ -3197,7 +3197,7 @@ static void init_channel(struct peer *peer)
 					 &funding_pubkey[LOCAL],
 					 &funding_pubkey[REMOTE],
 					 option_static_remotekey,
-					 funder);
+					 opener);
 
 	if (!channel_force_htlcs(peer->channel,
 			 cast_const2(const struct existing_htlc **, htlcs)))
@@ -3211,7 +3211,7 @@ static void init_channel(struct peer *peer)
 					      &peer->node_ids[REMOTE]);
 
 	/* Default desired feerate is the feerate we set for them last. */
-	if (peer->channel->funder == LOCAL)
+	if (peer->channel->opener == LOCAL)
 		peer->desired_feerate = channel_feerate(peer->channel, REMOTE);
 
 	/* from now we need keep watch over WIRE_CHANNEL_FUNDING_DEPTH */

channeld/commit_tx.c

@@ -85,7 +85,7 @@ struct bitcoin_tx *commit_tx(const tal_t *ctx,
 			     const struct bitcoin_txid *funding_txid,
 			     unsigned int funding_txout,
 			     struct amount_sat funding,
-			     enum side funder,
+			     enum side opener,
 			     u16 to_self_delay,
 			     const struct keyset *keyset,
 			     u32 feerate_per_kw,
@@ -131,7 +131,7 @@ struct bitcoin_tx *commit_tx(const tal_t *ctx,
 	 * 3. Subtract this base fee from the funder (either `to_local` or
 	 * `to_remote`), with a floor of 0 (see [Fee Payment](#fee-payment)).
 	 */
-	try_subtract_fee(funder, side, base_fee, &self_pay, &other_pay);
+	try_subtract_fee(opener, side, base_fee, &self_pay, &other_pay);
 
 #ifdef PRINT_ACTUAL_FEE
 	{

channeld/commit_tx.h

@@ -28,7 +28,7 @@ size_t commit_tx_num_untrimmed(const struct htlc **htlcs,
  * commit_tx: create (unsigned) commitment tx to spend the funding tx output
  * @ctx: context to allocate transaction and @htlc_map from.
  * @funding_txid, @funding_out, @funding: funding outpoint.
- * @funder: is the LOCAL or REMOTE paying the fee?
+ * @opener: is the LOCAL or REMOTE paying the fee?
  * @keyset: keys derived for this commit tx.
  * @feerate_per_kw: feerate to use
  * @dust_limit: dust limit below which to trim outputs.
@@ -47,7 +47,7 @@ struct bitcoin_tx *commit_tx(const tal_t *ctx,
 			     const struct bitcoin_txid *funding_txid,
 			     unsigned int funding_txout,
 			     struct amount_sat funding,
-			     enum side funder,
+			     enum side opener,
 			     u16 to_self_delay,
 			     const struct keyset *keyset,
 			     u32 feerate_per_kw,

channeld/full_channel.c

@@ -101,7 +101,7 @@ struct channel *new_full_channel(const tal_t *ctx,
 				 const struct pubkey *local_funding_pubkey,
 				 const struct pubkey *remote_funding_pubkey,
 				 bool option_static_remotekey,
-				 enum side funder)
+				 enum side opener)
 {
 	struct channel *channel = new_initial_channel(ctx,
 						      funding_txid,
@@ -116,7 +116,7 @@ struct channel *new_full_channel(const tal_t *ctx,
 						      local_funding_pubkey,
 						      remote_funding_pubkey,
 						      option_static_remotekey,
-						      funder);
+						      opener);
 
 	if (channel) {
 		channel->htlcs = tal(channel, struct htlc_map);
@@ -295,7 +295,7 @@ struct bitcoin_tx **channel_txs(const tal_t *ctx,
 	txs = tal_arr(ctx, struct bitcoin_tx *, 1);
 	txs[0] = commit_tx(
 	    ctx, &channel->funding_txid, channel->funding_txout,
-	    channel->funding, channel->funder,
+	    channel->funding, channel->opener,
 	    channel->config[!side].to_self_delay, &keyset,
 	    channel_feerate(channel, side),
 	    channel->config[side].dust_limit, channel->view[side].owed[side],
@@ -384,8 +384,8 @@ static struct amount_sat fee_for_htlcs(const struct channel *channel,
 }
 
 /*
- * There is a corner case where the funder can spend so much that the
- * non-funder can't add any non-dust HTLCs (since the funder would
+ * There is a corner case where the opener can spend so much that the
+ * non-opener can't add any non-dust HTLCs (since the opener would
  * have to pay the additional fee, but it can't afford to).  This
  * leads to the channel starving at the feast!  This was reported by
  * ACINQ's @t-bast
@@ -394,7 +394,7 @@ static struct amount_sat fee_for_htlcs(const struct channel *channel,
  * (https://github.com/ElementsProject/lightning/pull/3498).
  *
  * To mostly avoid this situation, at least from our side, we apply an
- * additional constraint when we're funder trying to add an HTLC: make
+ * additional constraint when we're opener trying to add an HTLC: make
  * sure we can afford one more HTLC, even if fees increase by 100%.
  *
  * We could do this for the peer, as well, by rejecting their HTLC
@@ -408,7 +408,7 @@ static struct amount_sat fee_for_htlcs(const struct channel *channel,
  * This mitigation will become BOLT #2 standard by:
  * https://github.com/lightningnetwork/lightning-rfc/issues/740
  */
-static bool local_funder_has_fee_headroom(const struct channel *channel,
+static bool local_opener_has_fee_headroom(const struct channel *channel,
 					  struct amount_msat remainder,
 					  const struct htlc **committed,
 					  const struct htlc **adding,
@@ -418,7 +418,7 @@ static bool local_funder_has_fee_headroom(const struct channel *channel,
 	size_t untrimmed;
 	struct amount_sat fee;
 
-	assert(channel->funder == LOCAL);
+	assert(channel->opener == LOCAL);
 
 	/* How many untrimmed at current feerate?   Increasing feerate can
 	 * only *reduce* this number, so use current feerate here! */
@@ -540,7 +540,7 @@ static enum channel_add_err add_htlc(struct channel *channel,
 	 */
 	/* Also we should not add more htlc's than sender or recipient
 	 * configured.  This mitigates attacks in which a peer can force the
-	 * funder of the channel to pay unnecessary onchain fees during a fee
+	 * opener of the channel to pay unnecessary onchain fees during a fee
 	 * spike with large commitment transactions.
 	 */
 	min_concurrent_htlcs = channel->config[recipient].max_accepted_htlcs;
@@ -614,7 +614,7 @@ static enum channel_add_err add_htlc(struct channel *channel,
 					    &remainder))
 			return CHANNEL_ERR_CHANNEL_CAPACITY_EXCEEDED;
 
-		if (channel->funder == sender) {
+		if (channel->opener== sender) {
 			if (amount_msat_less_sat(remainder, fee)) {
 				status_debug("Cannot afford fee %s with %s above reserve",
 					     type_to_string(tmpctx, struct amount_sat,
@@ -625,7 +625,7 @@ static enum channel_add_err add_htlc(struct channel *channel,
 			}
 
 			if (sender == LOCAL
-			    && !local_funder_has_fee_headroom(channel,
+			    && !local_opener_has_fee_headroom(channel,
 							      remainder,
 							      committed,
 							      adding,
@@ -634,12 +634,12 @@ static enum channel_add_err add_htlc(struct channel *channel,
 			}
 		}
 
-		/* Try not to add a payment which will take funder into fees
+		/* Try not to add a payment which will take opener into fees
 		 * on either our side or theirs. */
 		if (sender == LOCAL) {
 			if (!get_room_above_reserve(channel, view,
 						    adding, removing,
-						    channel->funder,
+						    channel->opener,
 						    &remainder))
 				return CHANNEL_ERR_CHANNEL_CAPACITY_EXCEEDED;
 			/* Should be able to afford both their own commit tx
@@ -649,7 +649,7 @@ static enum channel_add_err add_htlc(struct channel *channel,
 					    committed,
 					    adding,
 					    removing,
-					    channel->funder);
+					    channel->opener);
 			/* set fee output pointer if given */
 			if (htlc_fee && amount_sat_greater(fee, *htlc_fee))
 				*htlc_fee = fee;
@@ -667,7 +667,7 @@ static enum channel_add_err add_htlc(struct channel *channel,
 					    committed,
 					    adding,
 					    removing,
-					    !channel->funder);
+					    !channel->opener);
 			/* set fee output pointer if given */
 			if (htlc_fee && amount_sat_greater(fee, *htlc_fee))
 				*htlc_fee = fee;
@@ -970,7 +970,7 @@ u32 approx_max_feerate(const struct channel *channel)
 	struct amount_sat avail;
 	const struct htlc **committed, **adding, **removing;
 
-	gather_htlcs(tmpctx, channel, !channel->funder,
+	gather_htlcs(tmpctx, channel, !channel->opener,
 		     &committed, &removing, &adding);
 
 	/* Assume none are trimmed; this gives lower bound on feerate. */
@@ -1001,28 +1001,28 @@ u32 approx_max_feerate(const struct channel *channel)
 
 	/* We should never go below reserve. */
 	if (!amount_sat_sub(&avail,
-			    amount_msat_to_sat_round_down(channel->view[!channel->funder].owed[channel->funder]),
-			    channel->config[!channel->funder].channel_reserve))
+			    amount_msat_to_sat_round_down(channel->view[!channel->opener].owed[channel->opener]),
+			    channel->config[!channel->opener].channel_reserve))
 		avail = AMOUNT_SAT(0);
 
 	return avail.satoshis / weight * 1000; /* Raw: once-off reverse feerate*/
 }
 
-bool can_funder_afford_feerate(const struct channel *channel, u32 feerate_per_kw)
+bool can_opener_afford_feerate(const struct channel *channel, u32 feerate_per_kw)
 {
 	struct amount_sat needed, fee;
-	struct amount_sat dust_limit = channel->config[!channel->funder].dust_limit;
+	struct amount_sat dust_limit = channel->config[!channel->opener].dust_limit;
 	size_t untrimmed;
 	const struct htlc **committed, **adding, **removing;
-	gather_htlcs(tmpctx, channel, !channel->funder,
+	gather_htlcs(tmpctx, channel, !channel->opener,
 		     &committed, &removing, &adding);
 
 	untrimmed = commit_tx_num_untrimmed(committed, feerate_per_kw, dust_limit,
-					    !channel->funder)
+					    !channel->opener)
 			+ commit_tx_num_untrimmed(adding, feerate_per_kw, dust_limit,
-						  !channel->funder)
+						  !channel->opener)
 			- commit_tx_num_untrimmed(removing, feerate_per_kw, dust_limit,
-						  !channel->funder);
+						  !channel->opener);
 
 	fee = commit_tx_base_fee(feerate_per_kw, untrimmed);
 
@@ -1032,38 +1032,38 @@ bool can_funder_afford_feerate(const struct channel *channel, u32 feerate_per_kw
 	 *     node's current commitment transaction:
 	 *     - SHOULD fail the channel
 	 */
-	/* Note: sender == funder */
+	/* Note: sender == opener */
 
 	/* How much does it think it has?  Must be >= reserve + fee */
 	if (!amount_sat_add(&needed, fee,
-			    channel->config[!channel->funder].channel_reserve))
+			    channel->config[!channel->opener].channel_reserve))
 		status_failed(STATUS_FAIL_INTERNAL_ERROR,
 			      "Cannot add fee %s and reserve %s",
 			      type_to_string(tmpctx, struct amount_sat,
 					     &fee),
 			      type_to_string(tmpctx, struct amount_sat,
-					     &channel->config[!channel->funder].channel_reserve));
+					     &channel->config[!channel->opener].channel_reserve));
 
 	status_debug("We need %s at feerate %u for %zu untrimmed htlcs: we have %s/%s",
 		     type_to_string(tmpctx, struct amount_sat, &needed),
 		     feerate_per_kw, untrimmed,
 		     type_to_string(tmpctx, struct amount_msat,
-				    &channel->view[LOCAL].owed[channel->funder]),
+				    &channel->view[LOCAL].owed[channel->opener]),
 		     type_to_string(tmpctx, struct amount_msat,
-				    &channel->view[REMOTE].owed[channel->funder]));
-	return amount_msat_greater_eq_sat(channel->view[!channel->funder].owed[channel->funder],
+				    &channel->view[REMOTE].owed[channel->opener]));
+	return amount_msat_greater_eq_sat(channel->view[!channel->opener].owed[channel->opener],
 					  needed);
 }
 
 bool channel_update_feerate(struct channel *channel, u32 feerate_per_kw)
 {
-	if (!can_funder_afford_feerate(channel, feerate_per_kw))
+	if (!can_opener_afford_feerate(channel, feerate_per_kw))
 		return false;
 
 	status_debug("Setting %s feerate to %u",
-		     side_to_str(!channel->funder), feerate_per_kw);
+		     side_to_str(!channel->opener), feerate_per_kw);
 
-	start_fee_update(channel->fee_states, channel->funder, feerate_per_kw);
+	start_fee_update(channel->fee_states, channel->opener, feerate_per_kw);
 	return true;
 }