use bitcoin_hashes::hash160::Hash as Hash160;
use bitcoin_hashes::sha256d::Hash as Sha256dHash;
-use ln::channelmanager::PaymentHash;
+use ln::channelmanager::{PaymentHash, PaymentPreimage};
use ln::msgs::DecodeError;
use util::ser::{Readable, Writeable, Writer, WriterWriteAdaptor};
-use secp256k1::key::{SecretKey,PublicKey};
+use secp256k1::key::{SecretKey, PublicKey};
use secp256k1::{Secp256k1, Signature};
use secp256k1;
pub(super) const HTLC_SUCCESS_TX_WEIGHT: u64 = 703;
pub(super) const HTLC_TIMEOUT_TX_WEIGHT: u64 = 663;
+#[derive(PartialEq)]
+pub(crate) enum HTLCType {
+ AcceptedHTLC,
+ OfferedHTLC
+}
+
+impl HTLCType {
+ /// Check if a given tx witnessScript len matchs one of a pre-signed HTLC
+ pub(crate) fn scriptlen_to_htlctype(witness_script_len: usize) -> Option<HTLCType> {
+ if witness_script_len == 133 {
+ Some(HTLCType::OfferedHTLC)
+ } else if witness_script_len >= 136 && witness_script_len <= 139 {
+ Some(HTLCType::AcceptedHTLC)
+ } else {
+ None
+ }
+ }
+}
+
// Various functions for key derivation and transaction creation for use within channels. Primarily
// used in Channel and ChannelMonitor.
base_point.combine(&hashkey)
}
-/// Derives a revocation key from its constituent parts
+/// Derives a revocation key from its constituent parts.
+/// Note that this is infallible iff we trust that at least one of the two input keys are randomly
+/// generated (ie our own).
pub(super) fn derive_private_revocation_key<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, per_commitment_secret: &SecretKey, revocation_base_secret: &SecretKey) -> Result<SecretKey, secp256k1::Error> {
let revocation_base_point = PublicKey::from_secret_key(&secp_ctx, &revocation_base_secret);
let per_commitment_point = PublicKey::from_secret_key(&secp_ctx, &per_commitment_secret);
/// The set of public keys which are used in the creation of one commitment transaction.
/// These are derived from the channel base keys and per-commitment data.
+#[derive(PartialEq)]
pub struct TxCreationKeys {
/// The per-commitment public key which was used to derive the other keys.
pub per_commitment_point: PublicKey,
/// The revocation key which is used to allow the owner of the commitment transaction to
/// provide their counterparty the ability to punish them if they broadcast an old state.
- pub revocation_key: PublicKey,
+ pub(crate) revocation_key: PublicKey,
/// A's HTLC Key
- pub a_htlc_key: PublicKey,
+ pub(crate) a_htlc_key: PublicKey,
/// B's HTLC Key
- pub b_htlc_key: PublicKey,
+ pub(crate) b_htlc_key: PublicKey,
/// A's Payment Key (which isn't allowed to be spent from for some delay)
- pub a_delayed_payment_key: PublicKey,
+ pub(crate) a_delayed_payment_key: PublicKey,
/// B's Payment Key
- pub b_payment_key: PublicKey,
+ pub(crate) b_payment_key: PublicKey,
}
+/// One counterparty's public keys which do not change over the life of a channel.
+#[derive(Clone, PartialEq)]
+pub struct ChannelPublicKeys {
+ /// The public key which is used to sign all commitment transactions, as it appears in the
+ /// on-chain channel lock-in 2-of-2 multisig output.
+ pub funding_pubkey: PublicKey,
+ /// The base point which is used (with derive_public_revocation_key) to derive per-commitment
+ /// revocation keys. The per-commitment revocation private key is then revealed by the owner of
+ /// a commitment transaction so that their counterparty can claim all available funds if they
+ /// broadcast an old state.
+ pub revocation_basepoint: PublicKey,
+ /// The base point which is used (with derive_public_key) to derive a per-commitment payment
+ /// public key which receives immediately-spendable non-HTLC-encumbered funds.
+ pub payment_basepoint: PublicKey,
+ /// The base point which is used (with derive_public_key) to derive a per-commitment payment
+ /// public key which receives non-HTLC-encumbered funds which are only available for spending
+ /// after some delay (or can be claimed via the revocation path).
+ pub delayed_payment_basepoint: PublicKey,
+ /// The base point which is used (with derive_public_key) to derive a per-commitment public key
+ /// which is used to encumber HTLC-in-flight outputs.
+ pub htlc_basepoint: PublicKey,
+}
+
+impl_writeable!(ChannelPublicKeys, 33*5, {
+ funding_pubkey,
+ revocation_basepoint,
+ payment_basepoint,
+ delayed_payment_basepoint,
+ htlc_basepoint
+});
+
+
impl TxCreationKeys {
- pub(super) fn new<T: secp256k1::Signing + secp256k1::Verification>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, a_delayed_payment_base: &PublicKey, a_htlc_base: &PublicKey, b_revocation_base: &PublicKey, b_payment_base: &PublicKey, b_htlc_base: &PublicKey) -> Result<TxCreationKeys, secp256k1::Error> {
+ pub(crate) fn new<T: secp256k1::Signing + secp256k1::Verification>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, a_delayed_payment_base: &PublicKey, a_htlc_base: &PublicKey, b_revocation_base: &PublicKey, b_payment_base: &PublicKey, b_htlc_base: &PublicKey) -> Result<TxCreationKeys, secp256k1::Error> {
Ok(TxCreationKeys {
per_commitment_point: per_commitment_point.clone(),
revocation_key: derive_public_revocation_key(&secp_ctx, &per_commitment_point, &b_revocation_base)?,
get_htlc_redeemscript_with_explicit_keys(htlc, &keys.a_htlc_key, &keys.b_htlc_key, &keys.revocation_key)
}
+/// Gets the redeemscript for a funding output from the two funding public keys.
+/// Note that the order of funding public keys does not matter.
+pub fn make_funding_redeemscript(a: &PublicKey, b: &PublicKey) -> Script {
+ let our_funding_key = a.serialize();
+ let their_funding_key = b.serialize();
+
+ let builder = Builder::new().push_opcode(opcodes::all::OP_PUSHNUM_2);
+ if our_funding_key[..] < their_funding_key[..] {
+ builder.push_slice(&our_funding_key)
+ .push_slice(&their_funding_key)
+ } else {
+ builder.push_slice(&their_funding_key)
+ .push_slice(&our_funding_key)
+ }.push_opcode(opcodes::all::OP_PUSHNUM_2).push_opcode(opcodes::all::OP_CHECKMULTISIG).into_script()
+}
+
/// panics if htlc.transaction_output_index.is_none()!
pub fn build_htlc_transaction(prev_hash: &Sha256dHash, feerate_per_kw: u64, to_self_delay: u16, htlc: &HTLCOutputInCommitment, a_delayed_payment_key: &PublicKey, revocation_key: &PublicKey) -> Transaction {
let mut txins: Vec<TxIn> = Vec::new();
}
}
+/// Signs a transaction created by build_htlc_transaction. If the transaction is an
+/// HTLC-Success transaction (ie htlc.offered is false), preimage must be set!
+pub(crate) fn sign_htlc_transaction<T: secp256k1::Signing>(tx: &mut Transaction, their_sig: &Signature, preimage: &Option<PaymentPreimage>, htlc: &HTLCOutputInCommitment, a_htlc_key: &PublicKey, b_htlc_key: &PublicKey, revocation_key: &PublicKey, per_commitment_point: &PublicKey, htlc_base_key: &SecretKey, secp_ctx: &Secp256k1<T>) -> Result<(Signature, Script), ()> {
+ if tx.input.len() != 1 { return Err(()); }
+ if tx.input[0].witness.len() != 0 { return Err(()); }
+
+ let htlc_redeemscript = get_htlc_redeemscript_with_explicit_keys(&htlc, a_htlc_key, b_htlc_key, revocation_key);
+
+ let our_htlc_key = derive_private_key(secp_ctx, per_commitment_point, htlc_base_key).map_err(|_| ())?;
+ let sighash = hash_to_message!(&bip143::SighashComponents::new(&tx).sighash_all(&tx.input[0], &htlc_redeemscript, htlc.amount_msat / 1000)[..]);
+ let local_tx = PublicKey::from_secret_key(&secp_ctx, &our_htlc_key) == *a_htlc_key;
+ let our_sig = secp_ctx.sign(&sighash, &our_htlc_key);
+
+ tx.input[0].witness.push(Vec::new()); // First is the multisig dummy
+
+ if local_tx { // b, then a
+ tx.input[0].witness.push(their_sig.serialize_der().to_vec());
+ tx.input[0].witness.push(our_sig.serialize_der().to_vec());
+ } else {
+ tx.input[0].witness.push(our_sig.serialize_der().to_vec());
+ tx.input[0].witness.push(their_sig.serialize_der().to_vec());
+ }
+ tx.input[0].witness[1].push(SigHashType::All as u8);
+ tx.input[0].witness[2].push(SigHashType::All as u8);
+
+ if htlc.offered {
+ tx.input[0].witness.push(Vec::new());
+ assert!(preimage.is_none());
+ } else {
+ tx.input[0].witness.push(preimage.unwrap().0.to_vec());
+ }
+
+ tx.input[0].witness.push(htlc_redeemscript.as_bytes().to_vec());
+
+ Ok((our_sig, htlc_redeemscript))
+}
+
#[derive(Clone)]
/// We use this to track local commitment transactions and put off signing them until we are ready
/// to broadcast. Eventually this will require a signer which is possibly external, but for now we
projects / rust-lightning / blobdiff