From: Antoine Riard <ariard@student.42.fr>
Date: Wed, 10 Jul 2019 19:48:23 +0000 (-0400)
Subject: Support option_data_loss_protect for remote peer
X-Git-Tag: v0.0.12~189^2~4
X-Git-Url: http://git.bitcoin.ninja/?a=commitdiff_plain;h=2869e50d67ad5fc18b9434c771d7c227ead800ce;p=rust-lightning

Support option_data_loss_protect for remote peer

In case of sending channel_reestablish message, we join
our current per_commitment_point and their highest revocation
secret we know about

We set data_loss_protect by default and adjust encoding_init
test in consequence
---

diff --git a/src/ln/channel.rs b/src/ln/channel.rs
index 5abbd4a29..72b9fab14 100644
--- a/src/ln/channel.rs
+++ b/src/ln/channel.rs
@@ -16,7 +16,7 @@ use secp256k1::{Secp256k1,Signature};
 use secp256k1;
 
 use ln::msgs;
-use ln::msgs::{DecodeError, OptionalField, LocalFeatures};
+use ln::msgs::{DecodeError, OptionalField, LocalFeatures, DataLossProtect};
 use ln::channelmonitor::ChannelMonitor;
 use ln::channelmanager::{PendingHTLCStatus, HTLCSource, HTLCFailReason, HTLCFailureMsg, PendingForwardHTLCInfo, RAACommitmentOrder, PaymentPreimage, PaymentHash, BREAKDOWN_TIMEOUT, MAX_LOCAL_BREAKDOWN_TIMEOUT};
 use ln::chan_utils::{TxCreationKeys,HTLCOutputInCommitment,HTLC_SUCCESS_TX_WEIGHT,HTLC_TIMEOUT_TX_WEIGHT};
@@ -3256,6 +3256,20 @@ impl Channel {
 	pub fn get_channel_reestablish(&self) -> msgs::ChannelReestablish {
 		assert_eq!(self.channel_state & ChannelState::PeerDisconnected as u32, ChannelState::PeerDisconnected as u32);
 		assert_ne!(self.cur_remote_commitment_transaction_number, INITIAL_COMMITMENT_NUMBER);
+		let data_loss_protect = if self.cur_remote_commitment_transaction_number + 1 < INITIAL_COMMITMENT_NUMBER {
+			let remote_last_secret = self.channel_monitor.get_secret(self.cur_remote_commitment_transaction_number + 2).unwrap();
+			log_trace!(self, "Enough info to generate a Data Loss Protect with per_commitment_secret {}", log_bytes!(remote_last_secret));
+			OptionalField::Present(DataLossProtect {
+				your_last_per_commitment_secret: remote_last_secret,
+				my_current_per_commitment_point: PublicKey::from_secret_key(&self.secp_ctx, &self.build_local_commitment_secret(self.cur_local_commitment_transaction_number + 1))
+			})
+		} else {
+			log_debug!(self, "We don't seen yet any revoked secret, if this channnel has already been updated it means we are fallen-behind, you should wait for other peer closing");
+			OptionalField::Present(DataLossProtect {
+				your_last_per_commitment_secret: [0;32],
+				my_current_per_commitment_point: PublicKey::from_secret_key(&self.secp_ctx, &self.build_local_commitment_secret(self.cur_local_commitment_transaction_number))
+			})
+		};
 		msgs::ChannelReestablish {
 			channel_id: self.channel_id(),
 			// The protocol has two different commitment number concepts - the "commitment
@@ -3276,7 +3290,7 @@ impl Channel {
 			// dropped this channel on disconnect as it hasn't yet reached FundingSent so we can't
 			// overflow here.
 			next_remote_commitment_number: INITIAL_COMMITMENT_NUMBER - self.cur_remote_commitment_transaction_number - 1,
-			data_loss_protect: OptionalField::Absent,
+			data_loss_protect,
 		}
 	}
 
diff --git a/src/ln/msgs.rs b/src/ln/msgs.rs
index f6968c5d3..0e6c4b95e 100644
--- a/src/ln/msgs.rs
+++ b/src/ln/msgs.rs
@@ -63,23 +63,19 @@ impl LocalFeatures {
 	#[cfg(not(feature = "fuzztarget"))]
 	pub(crate) fn new() -> LocalFeatures {
 		LocalFeatures {
-			flags: vec![1 << 5],
+			flags: vec![2 | 1 << 5],
 		}
 	}
 	#[cfg(feature = "fuzztarget")]
 	pub fn new() -> LocalFeatures {
 		LocalFeatures {
-			flags: vec![1 << 5],
+			flags: vec![2 | 1 << 5],
 		}
 	}
 
 	pub(crate) fn supports_data_loss_protect(&self) -> bool {
 		self.flags.len() > 0 && (self.flags[0] & 3) != 0
 	}
-	pub(crate) fn requires_data_loss_protect(&self) -> bool {
-		self.flags.len() > 0 && (self.flags[0] & 1) != 0
-	}
-
 	pub(crate) fn initial_routing_sync(&self) -> bool {
 		self.flags.len() > 0 && (self.flags[0] & (1 << 3)) != 0
 	}
@@ -2018,9 +2014,9 @@ mod tests {
 			target_value.append(&mut hex::decode("0000").unwrap());
 		}
 		if initial_routing_sync {
-			target_value.append(&mut hex::decode("000128").unwrap());
+			target_value.append(&mut hex::decode("00012a").unwrap());
 		} else {
-			target_value.append(&mut hex::decode("000120").unwrap());
+			target_value.append(&mut hex::decode("000122").unwrap());
 		}
 		assert_eq!(encoded_value, target_value);
 	}
diff --git a/src/ln/peer_handler.rs b/src/ln/peer_handler.rs
index 03aeedcda..0e390bd32 100644
--- a/src/ln/peer_handler.rs
+++ b/src/ln/peer_handler.rs
@@ -621,10 +621,6 @@ impl<Descriptor: SocketDescriptor> PeerManager<Descriptor> {
 													log_info!(self, "Peer local features required unknown version bits");
 													return Err(PeerHandleError{ no_connection_possible: true });
 												}
-												if msg.local_features.requires_data_loss_protect() {
-													log_info!(self, "Peer local features required data_loss_protect");
-													return Err(PeerHandleError{ no_connection_possible: true });
-												}
 												if peer.their_global_features.is_some() {
 													return Err(PeerHandleError{ no_connection_possible: false });
 												}