X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fln%2Fchannel.rs;h=9a586254beaad85cce559fa898846db5135b2ffe;hb=HEAD;hp=306d4c5954b9cb4a3d89aa7bb373f044e85020d6;hpb=d5d4337edc111852c83ab1dd68299bc308759673;p=rust-lightning

diff --git a/lightning/src/ln/channel.rs b/lightning/src/ln/channel.rs
index 306d4c59..9a586254 100644
--- a/lightning/src/ln/channel.rs
+++ b/lightning/src/ln/channel.rs
@@ -371,14 +371,16 @@ const SPENDING_INPUT_FOR_A_OUTPUT_WEIGHT: u64 = 79; // prevout: 36, nSequence: 4
 const B_OUTPUT_PLUS_SPENDING_INPUT_WEIGHT: u64 = 104; // prevout: 40, nSequence: 4, script len: 1, witness lengths: 3/4, sig: 73/4, pubkey: 33/4, output: 31 (TODO: Wrong? Useless?)
 
 #[cfg(not(test))]
-const COMMITMENT_TX_BASE_WEIGHT: u64 = 724;
+const COMMITMENT_TX_BASE_WEIGHT: u64 = 896;
 #[cfg(test)]
-pub const COMMITMENT_TX_BASE_WEIGHT: u64 = 724;
+pub const COMMITMENT_TX_BASE_WEIGHT: u64 = 896;
 #[cfg(not(test))]
 const COMMITMENT_TX_WEIGHT_PER_HTLC: u64 = 172;
 #[cfg(test)]
 pub const COMMITMENT_TX_WEIGHT_PER_HTLC: u64 = 172;
 
+const ANCHOR_VALUE_SATOSHIS: u64 = 330;
+
 /// Maximmum `funding_satoshis` value, according to the BOLT #2 specification
 /// it's 2^24.
 pub const MAX_FUNDING_SATOSHIS: u64 = 1 << 24;
@@ -648,13 +650,14 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		// check if the funder's amount for the initial commitment tx is sufficient
 		// for full fee payment
 		let funders_amount_msat = msg.funding_satoshis * 1000 - msg.push_msat;
-		if funders_amount_msat < background_feerate * COMMITMENT_TX_BASE_WEIGHT {
+		if funders_amount_msat < background_feerate * COMMITMENT_TX_BASE_WEIGHT + ANCHOR_VALUE_SATOSHIS * 1000 {
 			return Err(ChannelError::Close("Insufficient funding amount for initial commitment"));
 		}
 
-		let to_local_msat = msg.push_msat;
-		let to_remote_msat = funders_amount_msat - background_feerate * COMMITMENT_TX_BASE_WEIGHT;
-		if to_local_msat <= msg.channel_reserve_satoshis * 1000 && to_remote_msat <= remote_channel_reserve_satoshis * 1000 {
+		let to_remote_msat = funders_amount_msat - background_feerate * COMMITMENT_TX_BASE_WEIGHT - ANCHOR_VALUE_SATOSHIS * 1000;
+		// While its reasonable for us to not meet the channel reserve initially (if they don't
+		// want to push much to us), our counterparty should always have more than the reserve.
+		if to_remote_msat <= remote_channel_reserve_satoshis * 1000 {
 			return Err(ChannelError::Close("Insufficient funding amount for initial commitment"));
 		}
 
@@ -954,14 +957,24 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 
 		let total_fee: u64 = feerate_per_kw * (COMMITMENT_TX_BASE_WEIGHT + (txouts.len() as u64) * COMMITMENT_TX_WEIGHT_PER_HTLC) / 1000;
 		let (value_to_self, value_to_remote) = if self.channel_outbound {
-			(value_to_self_msat / 1000 - total_fee as i64, value_to_remote_msat / 1000)
+			(value_to_self_msat / 1000 - total_fee as i64 - ANCHOR_VALUE_SATOSHIS as i64, value_to_remote_msat / 1000)
 		} else {
-			(value_to_self_msat / 1000, value_to_remote_msat / 1000 - total_fee as i64)
+			(value_to_self_msat / 1000, value_to_remote_msat / 1000 - total_fee as i64 - ANCHOR_VALUE_SATOSHIS as i64)
 		};
+		debug_assert!(value_to_self >= 0);
+		debug_assert!(value_to_remote >= 0);
 
 		let value_to_a = if local { value_to_self } else { value_to_remote };
 		let value_to_b = if local { value_to_remote } else { value_to_self };
 
+		if value_to_a >= (dust_limit_satoshis as i64) || !txouts.is_empty() {
+			// Always push the anchor output so that local can get the transaction confirmed.
+			txouts.push((TxOut {
+				script_pubkey: Script::new(), //XXX
+				value: ANCHOR_VALUE_SATOSHIS
+			}, None));
+		}
+
 		if value_to_a >= (dust_limit_satoshis as i64) {
 			log_trace!(logger, "   ...including {} output with value {}", if local { "to_local" } else { "to_remote" }, value_to_a);
 			txouts.push((TxOut {
@@ -987,6 +1000,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			}, None));
 		}
 
+
 		transaction_utils::sort_outputs(&mut txouts, |a, b| {
 			if let &Some(ref a_htlc) = a {
 				if let &Some(ref b_htlc) = b {
@@ -1847,7 +1861,7 @@ debug_assert!(false, "This should be triggerable, and we should add a test case
 		//If channel fee was updated by funder confirm funder can afford the new fee rate when applied to the current local commitment transaction
 		if update_fee {
 			let num_htlcs = local_commitment_tx.1;
-			let total_fee: u64 = feerate_per_kw as u64 * (COMMITMENT_TX_BASE_WEIGHT + (num_htlcs as u64) * COMMITMENT_TX_WEIGHT_PER_HTLC) / 1000;
+			let total_fee: u64 = feerate_per_kw as u64 * (COMMITMENT_TX_BASE_WEIGHT + (num_htlcs as u64) * COMMITMENT_TX_WEIGHT_PER_HTLC) / 1000 + ANCHOR_VALUE_SATOSHIS;
 
 			let remote_reserve_we_require = Channel::<ChanSigner>::get_remote_channel_reserve_satoshis(self.channel_value_satoshis);
 			if self.channel_value_satoshis - self.value_to_self_msat / 1000 < total_fee + remote_reserve_we_require {