Structurify claim request handed between detection/reaction
authorAntoine Riard <ariard@student.42.fr>
Wed, 12 Feb 2020 18:00:29 +0000 (13:00 -0500)
committerAntoine Riard <ariard@student.42.fr>
Wed, 4 Mar 2020 21:06:31 +0000 (16:06 -0500)
lightning/src/ln/channelmonitor.rs
lightning/src/ln/onchaintx.rs

index a8fdb32aa3f7c1cda9ac20299cc48f839e4251be..67e306b462897843374a88e7cdbb6b9976908fc2 100644 (file)
@@ -554,6 +554,28 @@ impl Readable for InputMaterial {
        }
 }
 
+/// ClaimRequest is a descriptor structure to communicate between detection
+/// and reaction module. They are generated by ChannelMonitor while parsing
+/// onchain txn leaked from a channel and handed over to OnchainTxHandler which
+/// is responsible for opportunistic aggregation, selecting and enforcing
+/// bumping logic, building and signing transactions.
+pub(crate) struct ClaimRequest {
+       // Block height before which claiming is exclusive to one party,
+       // after reaching it, claiming may be contentious.
+       pub(crate) absolute_timelock: u32,
+       // Timeout tx must have nLocktime set which means aggregating multiple
+       // ones must take the higher nLocktime among them to satisfy all of them.
+       // Sadly it has few pitfalls, a) it takes longuer to get fund back b) CLTV_DELTA
+       // of a sooner-HTLC could be swallowed by the highest nLocktime of the HTLC set.
+       // Do simplify we mark them as non-aggregable.
+       pub(crate) aggregable: bool,
+       // Basic bitcoin outpoint (txid, vout)
+       pub(crate) outpoint: BitcoinOutPoint,
+       // Following outpoint type, set of data needed to generate transaction digest
+       // and satisfy witness program.
+       pub(crate) witness_data: InputMaterial
+}
+
 /// Upon discovering of some classes of onchain tx by ChannelMonitor, we may have to take actions on it
 /// once they mature to enough confirmations (ANTI_REORG_DELAY)
 #[derive(Clone, PartialEq)]
@@ -1385,7 +1407,7 @@ impl<ChanSigner: ChannelKeys> ChannelMonitor<ChanSigner> {
        /// HTLC-Success/HTLC-Timeout transactions.
        /// Return updates for HTLC pending in the channel and failed automatically by the broadcast of
        /// revoked remote commitment tx
-       fn check_spend_remote_transaction(&mut self, tx: &Transaction, height: u32) -> (Vec<(u32, bool, BitcoinOutPoint, InputMaterial)>, (Sha256dHash, Vec<TxOut>), Vec<SpendableOutputDescriptor>) {
+       fn check_spend_remote_transaction(&mut self, tx: &Transaction, height: u32) -> (Vec<ClaimRequest>, (Sha256dHash, Vec<TxOut>), Vec<SpendableOutputDescriptor>) {
                // Most secp and related errors trying to create keys means we have no hope of constructing
                // a spend transaction...so we return no transactions to broadcast
                let mut claimable_outpoints = Vec::new();
@@ -1439,7 +1461,8 @@ impl<ChanSigner: ChannelKeys> ChannelMonitor<ChanSigner> {
                        // First, process non-htlc outputs (to_local & to_remote)
                        for (idx, outp) in tx.output.iter().enumerate() {
                                if outp.script_pubkey == revokeable_p2wsh {
-                                       claimable_outpoints.push((height + self.our_to_self_delay as u32, true, BitcoinOutPoint { txid: commitment_txid, vout: idx as u32 }, InputMaterial::Revoked { script: revokeable_redeemscript.clone(), pubkey: Some(revocation_pubkey), key: revocation_key, is_htlc: false, amount: outp.value }));
+                                       let witness_data = InputMaterial::Revoked { script: revokeable_redeemscript.clone(), pubkey: Some(revocation_pubkey), key: revocation_key, is_htlc: false, amount: outp.value };
+                                       claimable_outpoints.push(ClaimRequest { absolute_timelock: height + self.our_to_self_delay as u32, aggregable: true, outpoint: BitcoinOutPoint { txid: commitment_txid, vout: idx as u32 }, witness_data});
                                } else if Some(&outp.script_pubkey) == local_payment_p2wpkh.as_ref() {
                                        spendable_outputs.push(SpendableOutputDescriptor::DynamicOutputP2WPKH {
                                                outpoint: BitcoinOutPoint { txid: commitment_txid, vout: idx as u32 },
@@ -1459,7 +1482,8 @@ impl<ChanSigner: ChannelKeys> ChannelMonitor<ChanSigner> {
                                                                tx.output[transaction_output_index as usize].script_pubkey != expected_script.to_v0_p2wsh() {
                                                        return (claimable_outpoints, (commitment_txid, watch_outputs), spendable_outputs); // Corrupted per_commitment_data, fuck this user
                                                }
-                                               claimable_outpoints.push((htlc.cltv_expiry, true, BitcoinOutPoint { txid: commitment_txid, vout: transaction_output_index }, InputMaterial::Revoked { script: expected_script, pubkey: Some(revocation_pubkey), key: revocation_key, is_htlc: true, amount: tx.output[transaction_output_index as usize].value }));
+                                               let witness_data = InputMaterial::Revoked { script: expected_script, pubkey: Some(revocation_pubkey), key: revocation_key, is_htlc: true, amount: tx.output[transaction_output_index as usize].value };
+                                               claimable_outpoints.push(ClaimRequest { absolute_timelock: htlc.cltv_expiry, aggregable: true, outpoint: BitcoinOutPoint { txid: commitment_txid, vout: transaction_output_index }, witness_data });
                                        }
                                }
                        }
@@ -1622,7 +1646,8 @@ impl<ChanSigner: ChannelKeys> ChannelMonitor<ChanSigner> {
                                                        let preimage = if htlc.offered { if let Some(p) = self.payment_preimages.get(&htlc.payment_hash) { Some(*p) } else { None } } else { None };
                                                        let aggregable = if !htlc.offered { false } else { true };
                                                        if preimage.is_some() || !htlc.offered {
-                                                               claimable_outpoints.push((htlc.cltv_expiry, aggregable, BitcoinOutPoint { txid: commitment_txid, vout: transaction_output_index }, InputMaterial::RemoteHTLC { script: expected_script, key: htlc_privkey, preimage, amount: htlc.amount_msat / 1000, locktime: htlc.cltv_expiry }));
+                                                               let witness_data = InputMaterial::RemoteHTLC { script: expected_script, key: htlc_privkey, preimage, amount: htlc.amount_msat / 1000, locktime: htlc.cltv_expiry };
+                                                               claimable_outpoints.push(ClaimRequest { absolute_timelock: htlc.cltv_expiry, aggregable, outpoint: BitcoinOutPoint { txid: commitment_txid, vout: transaction_output_index }, witness_data });
                                                        }
                                                }
                                        }
@@ -1643,7 +1668,7 @@ impl<ChanSigner: ChannelKeys> ChannelMonitor<ChanSigner> {
        }
 
        /// Attempts to claim a remote HTLC-Success/HTLC-Timeout's outputs using the revocation key
-       fn check_spend_remote_htlc(&mut self, tx: &Transaction, commitment_number: u64, height: u32) -> Vec<(u32, bool, BitcoinOutPoint, InputMaterial)> {
+       fn check_spend_remote_htlc(&mut self, tx: &Transaction, commitment_number: u64, height: u32) -> Vec<ClaimRequest> {
                //TODO: send back new outputs to guarantee pending_claim_request consistency
                if tx.input.len() != 1 || tx.output.len() != 1 || tx.input[0].witness.len() != 5 {
                        return Vec::new()
@@ -1676,7 +1701,8 @@ impl<ChanSigner: ChannelKeys> ChannelMonitor<ChanSigner> {
                let htlc_txid = tx.txid(); //TODO: This is gonna be a performance bottleneck for watchtowers!
 
                log_trace!(self, "Remote HTLC broadcast {}:{}", htlc_txid, 0);
-               let claimable_outpoints = vec!((height + self.our_to_self_delay as u32, true, BitcoinOutPoint { txid: htlc_txid, vout: 0}, InputMaterial::Revoked { script: redeemscript, pubkey: Some(revocation_pubkey), key: revocation_key, is_htlc: false, amount: tx.output[0].value }));
+               let witness_data = InputMaterial::Revoked { script: redeemscript, pubkey: Some(revocation_pubkey), key: revocation_key, is_htlc: false, amount: tx.output[0].value };
+               let claimable_outpoints = vec!(ClaimRequest { absolute_timelock: height + self.our_to_self_delay as u32, aggregable: true, outpoint: BitcoinOutPoint { txid: htlc_txid, vout: 0}, witness_data });
                claimable_outpoints
        }
 
@@ -2050,7 +2076,7 @@ impl<ChanSigner: ChannelKeys> ChannelMonitor<ChanSigner> {
                                }
                        }
                }
-               let mut spendable_output = self.onchain_tx_handler.block_connected(txn_matched, claimable_outpoints, height, broadcaster, &*fee_estimator);
+               let mut spendable_output = self.onchain_tx_handler.block_connected(txn_matched, claimable_outpoints, height, &*broadcaster, &*fee_estimator);
                spendable_outputs.append(&mut spendable_output);
 
                self.last_block_hash = block_hash.clone();
index 7bacc91a441a6113fe263d3caa45ecab3ec0485f..1166696f9cbb5299c02bb9817b4dad3f73969dca 100644 (file)
@@ -14,7 +14,7 @@ use secp256k1::Secp256k1;
 use secp256k1;
 
 use ln::msgs::DecodeError;
-use ln::channelmonitor::{ANTI_REORG_DELAY, CLTV_SHARED_CLAIM_BUFFER, InputMaterial};
+use ln::channelmonitor::{ANTI_REORG_DELAY, CLTV_SHARED_CLAIM_BUFFER, InputMaterial, ClaimRequest};
 use ln::chan_utils::HTLCType;
 use chain::chaininterface::{FeeEstimator, BroadcasterInterface, ConfirmationTarget, MIN_RELAY_FEE_SAT_PER_1000_WEIGHT};
 use chain::keysinterface::SpendableOutputDescriptor;
@@ -471,7 +471,7 @@ impl OnchainTxHandler {
                Some((new_timer, new_feerate, bumped_tx))
        }
 
-       pub(super) fn block_connected<B: Deref, F: Deref>(&mut self, txn_matched: &[&Transaction], claimable_outpoints: Vec<Vec<(u32, bool, BitcoinOutPoint, InputMaterial)>>, height: u32, broadcaster: B, fee_estimator: F) -> Vec<SpendableOutputDescriptor>
+       pub(super) fn block_connected<B: Deref, F: Deref>(&mut self, txn_matched: &[&Transaction], claimable_outpoints: Vec<Vec<ClaimRequest>>, height: u32, broadcaster: B, fee_estimator: F) -> Vec<SpendableOutputDescriptor>
                where B::Target: BroadcasterInterface,
                      F::Target: FeeEstimator
        {
@@ -483,18 +483,18 @@ impl OnchainTxHandler {
                // Try to aggregate outputs if they're 1) belong to same parent tx, 2) their
                // timelock expiration isn't imminent (<= CLTV_SHARED_CLAIM_BUFFER).
                for siblings_outpoints in claimable_outpoints {
-                       for outp in siblings_outpoints {
+                       for req in siblings_outpoints {
                                // Don't claim a outpoint twice that would be bad for privacy and may uselessly lock a CPFP input for a while
-                               if let Some(_) = self.claimable_outpoints.get(&outp.2) { log_trace!(self, "Bouncing off outpoint {}:{}, already registered its claiming request", outp.2.txid, outp.2.vout); } else {
-                                       log_trace!(self, "Test if outpoint can be aggregated with expiration {} against {}", outp.0, height + CLTV_SHARED_CLAIM_BUFFER);
-                                       if outp.0 <= height + CLTV_SHARED_CLAIM_BUFFER || !outp.1 { // Don't aggregate if outpoint absolute timelock is soon or marked as non-aggregable
+                               if let Some(_) = self.claimable_outpoints.get(&req.outpoint) { log_trace!(self, "Bouncing off outpoint {}:{}, already registered its claiming request", req.outpoint.txid, req.outpoint.vout); } else {
+                                       log_trace!(self, "Test if outpoint can be aggregated with expiration {} against {}", req.absolute_timelock, height + CLTV_SHARED_CLAIM_BUFFER);
+                                       if req.absolute_timelock <= height + CLTV_SHARED_CLAIM_BUFFER || !req.aggregable { // Don't aggregate if outpoint absolute timelock is soon or marked as non-aggregable
                                                let mut single_input = HashMap::new();
-                                               single_input.insert(outp.2, outp.3);
-                                               new_claims.push((outp.0, single_input));
+                                               single_input.insert(req.outpoint, req.witness_data);
+                                               new_claims.push((req.absolute_timelock, single_input));
                                        } else {
-                                               aggregated_claim.insert(outp.2, outp.3);
-                                               if outp.0 < aggregated_soonest {
-                                                       aggregated_soonest = outp.0;
+                                               aggregated_claim.insert(req.outpoint, req.witness_data);
+                                               if req.absolute_timelock < aggregated_soonest {
+                                                       aggregated_soonest = req.absolute_timelock;
                                                }
                                        }
                                }