Add baseline OnionMessenger and msgs::OnionMessage and its serialization
[rust-lightning] / lightning / src / ln / channel.rs
index 9b47770f120310cce58cc01bc4ab63d1a679b590..2da743033d3596f5176b17ee6b864f8fa7416679 100644 (file)
@@ -39,7 +39,7 @@ use util::events::ClosureReason;
 use util::ser::{Readable, ReadableArgs, Writeable, Writer, VecWriter};
 use util::logger::Logger;
 use util::errors::APIError;
-use util::config::{UserConfig, LegacyChannelConfig, ChannelHandshakeConfig, ChannelHandshakeLimits};
+use util::config::{UserConfig, ChannelConfig, LegacyChannelConfig, ChannelHandshakeConfig, ChannelHandshakeLimits};
 use util::scid_utils::scid_from_parts;
 
 use io;
@@ -482,6 +482,16 @@ pub(crate) const CONCURRENT_INBOUND_HTLC_FEE_BUFFER: u32 = 2;
 /// transaction (not counting the value of the HTLCs themselves).
 pub(crate) const MIN_AFFORDABLE_HTLC_COUNT: usize = 4;
 
+/// When a [`Channel`] has its [`ChannelConfig`] updated, its existing one is stashed for up to this
+/// number of ticks to allow forwarding HTLCs by nodes that have yet to receive the new
+/// ChannelUpdate prompted by the config update. This value was determined as follows:
+///
+///   * The expected interval between ticks (1 minute).
+///   * The average convergence delay of updates across the network, i.e., ~300 seconds on average
+///      for a node to see an update as seen on `<https://arxiv.org/pdf/2205.12737.pdf>`.
+///   * `EXPIRE_PREV_CONFIG_TICKS` = convergence_delay / tick_interval
+pub(crate) const EXPIRE_PREV_CONFIG_TICKS: usize = 5;
+
 // TODO: We should refactor this to be an Inbound/OutboundChannel until initial setup handshaking
 // has been completed, and then turn into a Channel to get compiler-time enforcement of things like
 // calling channel_id() before we're set up or things like get_outbound_funding_signed on an
@@ -490,11 +500,13 @@ pub(crate) const MIN_AFFORDABLE_HTLC_COUNT: usize = 4;
 // Holder designates channel data owned for the benefice of the user client.
 // Counterparty designates channel data owned by the another channel participant entity.
 pub(super) struct Channel<Signer: Sign> {
-       #[cfg(any(test, feature = "_test_utils"))]
-       pub(crate) config: LegacyChannelConfig,
-       #[cfg(not(any(test, feature = "_test_utils")))]
        config: LegacyChannelConfig,
 
+       // Track the previous `ChannelConfig` so that we can continue forwarding HTLCs that were
+       // constructed using it. The second element in the tuple corresponds to the number of ticks that
+       // have elapsed since the update occurred.
+       prev_config: Option<(ChannelConfig, usize)>,
+
        inbound_handshake_limits_override: Option<ChannelHandshakeLimits>,
 
        user_id: u64,
@@ -790,7 +802,6 @@ pub(super) enum ChannelError {
        Ignore(String),
        Warn(String),
        Close(String),
-       CloseDelayBroadcast(String),
 }
 
 impl fmt::Debug for ChannelError {
@@ -799,7 +810,6 @@ impl fmt::Debug for ChannelError {
                        &ChannelError::Ignore(ref e) => write!(f, "Ignore : {}", e),
                        &ChannelError::Warn(ref e) => write!(f, "Warn : {}", e),
                        &ChannelError::Close(ref e) => write!(f, "Close : {}", e),
-                       &ChannelError::CloseDelayBroadcast(ref e) => write!(f, "CloseDelayBroadcast : {}", e)
                }
        }
 }
@@ -937,6 +947,8 @@ impl<Signer: Sign> Channel<Signer> {
                                commit_upfront_shutdown_pubkey: config.channel_handshake_config.commit_upfront_shutdown_pubkey,
                        },
 
+                       prev_config: None,
+
                        inbound_handshake_limits_override: Some(config.channel_handshake_limits.clone()),
 
                        channel_id: keys_provider.get_secure_random_bytes(),
@@ -1264,6 +1276,8 @@ impl<Signer: Sign> Channel<Signer> {
                                commit_upfront_shutdown_pubkey: config.channel_handshake_config.commit_upfront_shutdown_pubkey,
                        },
 
+                       prev_config: None,
+
                        inbound_handshake_limits_override: None,
 
                        channel_id: msg.temporary_channel_id,
@@ -3783,6 +3797,11 @@ impl<Signer: Sign> Channel<Signer> {
 
        /// May panic if some calls other than message-handling calls (which will all Err immediately)
        /// have been called between remove_uncommitted_htlcs_and_mark_paused and this call.
+       ///
+       /// Some links printed in log lines are included here to check them during build (when run with
+       /// `cargo doc --document-private-items`):
+       /// [`super::channelmanager::ChannelManager::force_close_without_broadcasting_txn`] and
+       /// [`super::channelmanager::ChannelManager::force_close_all_channels_without_broadcasting_txn`].
        pub fn channel_reestablish<L: Deref>(&mut self, msg: &msgs::ChannelReestablish, logger: &L,
                node_pk: PublicKey, genesis_block_hash: BlockHash, best_block: &BestBlock)
        -> Result<ReestablishResponses, ChannelError> where L::Target: Logger {
@@ -3808,9 +3827,20 @@ impl<Signer: Sign> Channel<Signer> {
                                                return Err(ChannelError::Close("Peer sent a garbage channel_reestablish with secret key not matching the commitment height provided".to_owned()));
                                        }
                                        if msg.next_remote_commitment_number > INITIAL_COMMITMENT_NUMBER - self.cur_holder_commitment_transaction_number {
-                                               return Err(ChannelError::CloseDelayBroadcast(
-                                                       "We have fallen behind - we have received proof that if we broadcast remote is going to claim our funds - we can't do any automated broadcasting".to_owned()
-                                               ));
+                                               macro_rules! log_and_panic {
+                                                       ($err_msg: expr) => {
+                                                               log_error!(logger, $err_msg, log_bytes!(self.channel_id), log_pubkey!(self.counterparty_node_id));
+                                                               panic!($err_msg, log_bytes!(self.channel_id), log_pubkey!(self.counterparty_node_id));
+                                                       }
+                                               }
+                                               log_and_panic!("We have fallen behind - we have received proof that if we broadcast our counterparty is going to claim all our funds.\n\
+                                                       This implies you have restarted with lost ChannelMonitor and ChannelManager state, the first of which is a violation of the LDK chain::Watch requirements.\n\
+                                                       More specifically, this means you have a bug in your implementation that can cause loss of funds, or you are running with an old backup, which is unsafe.\n\
+                                                       If you have restored from an old backup and wish to force-close channels and return to operation, you should start up, call\n\
+                                                       ChannelManager::force_close_without_broadcasting_txn on channel {} with counterparty {} or\n\
+                                                       ChannelManager::force_close_all_channels_without_broadcasting_txn, then reconnect to peer(s).\n\
+                                                       Note that due to a long-standing bug in lnd you may have to reach out to peers running lnd-based nodes to ask them to manually force-close channels\n\
+                                                       See https://github.com/lightningdevkit/rust-lightning/issues/1565 for more info.");
                                        }
                                },
                                OptionalField::Absent => {}
@@ -3917,7 +3947,7 @@ impl<Signer: Sign> Channel<Signer> {
                                // now!
                                match self.free_holding_cell_htlcs(logger) {
                                        Err(ChannelError::Close(msg)) => Err(ChannelError::Close(msg)),
-                                       Err(ChannelError::Warn(_)) | Err(ChannelError::Ignore(_)) | Err(ChannelError::CloseDelayBroadcast(_)) =>
+                                       Err(ChannelError::Warn(_)) | Err(ChannelError::Ignore(_)) =>
                                                panic!("Got non-channel-failing result from free_holding_cell_htlcs"),
                                        Ok((Some((commitment_update, monitor_update)), holding_cell_failed_htlcs)) => {
                                                Ok(ReestablishResponses {
@@ -4491,6 +4521,84 @@ impl<Signer: Sign> Channel<Signer> {
                self.config.options.max_dust_htlc_exposure_msat
        }
 
+       /// Returns the previous [`ChannelConfig`] applied to this channel, if any.
+       pub fn prev_config(&self) -> Option<ChannelConfig> {
+               self.prev_config.map(|prev_config| prev_config.0)
+       }
+
+       /// Tracks the number of ticks elapsed since the previous [`ChannelConfig`] was updated. Once
+       /// [`EXPIRE_PREV_CONFIG_TICKS`] is reached, the previous config is considered expired and will
+       /// no longer be considered when forwarding HTLCs.
+       pub fn maybe_expire_prev_config(&mut self) {
+               if self.prev_config.is_none() {
+                       return;
+               }
+               let prev_config = self.prev_config.as_mut().unwrap();
+               prev_config.1 += 1;
+               if prev_config.1 == EXPIRE_PREV_CONFIG_TICKS {
+                       self.prev_config = None;
+               }
+       }
+
+       /// Returns the current [`ChannelConfig`] applied to the channel.
+       pub fn config(&self) -> ChannelConfig {
+               self.config.options
+       }
+
+       /// Updates the channel's config. A bool is returned indicating whether the config update
+       /// applied resulted in a new ChannelUpdate message.
+       pub fn update_config(&mut self, config: &ChannelConfig) -> bool {
+               let did_channel_update =
+                       self.config.options.forwarding_fee_proportional_millionths != config.forwarding_fee_proportional_millionths ||
+                       self.config.options.forwarding_fee_base_msat != config.forwarding_fee_base_msat ||
+                       self.config.options.cltv_expiry_delta != config.cltv_expiry_delta;
+               if did_channel_update {
+                       self.prev_config = Some((self.config.options, 0));
+                       // Update the counter, which backs the ChannelUpdate timestamp, to allow the relay
+                       // policy change to propagate throughout the network.
+                       self.update_time_counter += 1;
+               }
+               self.config.options = *config;
+               did_channel_update
+       }
+
+       fn internal_htlc_satisfies_config(
+               &self, htlc: &msgs::UpdateAddHTLC, amt_to_forward: u64, outgoing_cltv_value: u32, config: &ChannelConfig,
+       ) -> Result<(), (&'static str, u16)> {
+               let fee = amt_to_forward.checked_mul(config.forwarding_fee_proportional_millionths as u64)
+                       .and_then(|prop_fee| (prop_fee / 1000000).checked_add(config.forwarding_fee_base_msat as u64));
+               if fee.is_none() || htlc.amount_msat < fee.unwrap() ||
+                       (htlc.amount_msat - fee.unwrap()) < amt_to_forward {
+                       return Err((
+                               "Prior hop has deviated from specified fees parameters or origin node has obsolete ones",
+                               0x1000 | 12, // fee_insufficient
+                       ));
+               }
+               if (htlc.cltv_expiry as u64) < outgoing_cltv_value as u64 + config.cltv_expiry_delta as u64 {
+                       return Err((
+                               "Forwarding node has tampered with the intended HTLC values or origin node has an obsolete cltv_expiry_delta",
+                               0x1000 | 13, // incorrect_cltv_expiry
+                       ));
+               }
+               Ok(())
+       }
+
+       /// Determines whether the parameters of an incoming HTLC to be forwarded satisfy the channel's
+       /// [`ChannelConfig`]. This first looks at the channel's current [`ChannelConfig`], and if
+       /// unsuccessful, falls back to the previous one if one exists.
+       pub fn htlc_satisfies_config(
+               &self, htlc: &msgs::UpdateAddHTLC, amt_to_forward: u64, outgoing_cltv_value: u32,
+       ) -> Result<(), (&'static str, u16)> {
+               self.internal_htlc_satisfies_config(&htlc, amt_to_forward, outgoing_cltv_value, &self.config())
+                       .or_else(|err| {
+                               if let Some(prev_config) = self.prev_config() {
+                                       self.internal_htlc_satisfies_config(htlc, amt_to_forward, outgoing_cltv_value, &prev_config)
+                               } else {
+                                       Err(err)
+                               }
+                       })
+       }
+
        pub fn get_feerate(&self) -> u32 {
                self.feerate_per_kw
        }
@@ -6339,6 +6447,8 @@ impl<'a, Signer: Sign, K: Deref> ReadableArgs<(&'a K, u32)> for Channel<Signer>
 
                        config: config.unwrap(),
 
+                       prev_config: None,
+
                        // Note that we don't care about serializing handshake limits as we only ever serialize
                        // channel data after the handshake has completed.
                        inbound_handshake_limits_override: None,
@@ -6473,6 +6583,7 @@ mod tests {
        use bitcoin::secp256k1::{Secp256k1, ecdsa::Signature};
        use bitcoin::secp256k1::ffi::Signature as FFISignature;
        use bitcoin::secp256k1::{SecretKey,PublicKey};
+       use bitcoin::secp256k1::ecdh::SharedSecret;
        use bitcoin::secp256k1::ecdsa::RecoverableSignature;
        use bitcoin::hashes::sha256::Hash as Sha256;
        use bitcoin::hashes::Hash;
@@ -6511,6 +6622,7 @@ mod tests {
                type Signer = InMemorySigner;
 
                fn get_node_secret(&self, _recipient: Recipient) -> Result<SecretKey, ()> { panic!(); }
+               fn ecdh(&self, _recipient: Recipient, _other_key: &PublicKey, _tweak: Option<&[u8; 32]>) -> Result<SharedSecret, ()> { panic!(); }
                fn get_inbound_payment_key_material(&self) -> KeyMaterial { panic!(); }
                fn get_destination_script(&self) -> Script {
                        let secp_ctx = Secp256k1::signing_only();