Add get_anchor_script

[rust-lightning] / lightning / src / ln / chan_utils.rs

diff --git a/lightning/src/ln/chan_utils.rs b/lightning/src/ln/chan_utils.rs
index 6e0e50858f8972ff90865eb3c23f5c2ce39f10fa..982257b633673f05521d7788167059ebf60af0da 100644 (file)
--- a/lightning/src/ln/chan_utils.rs
+++ b/lightning/src/ln/chan_utils.rs
@@ -31,6 +31,7 @@ use bitcoin::secp256k1::{Secp256k1, Signature, Message};
 use bitcoin::secp256k1::Error as SecpError;
 use bitcoin::secp256k1;
 
+use io;
 use prelude::*;
 use core::cmp;
 use ln::chan_utils;
@@ -167,7 +168,7 @@ impl CounterpartyCommitmentSecrets {
 }
 
 impl Writeable for CounterpartyCommitmentSecrets {
-       fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
+       fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
                for &(ref secret, ref idx) in self.old_secrets.iter() {
                        writer.write_all(secret)?;
                        writer.write_all(&byte_utils::be64_to_array(*idx))?;
@@ -177,7 +178,7 @@ impl Writeable for CounterpartyCommitmentSecrets {
        }
 }
 impl Readable for CounterpartyCommitmentSecrets {
-       fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
+       fn read<R: io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
                let mut old_secrets = [([0; 32], 1 << 48); 49];
                for &mut (ref mut secret, ref mut idx) in old_secrets.iter_mut() {
                        *secret = Readable::read(reader)?;
@@ -563,6 +564,23 @@ pub fn build_htlc_transaction(commitment_txid: &Txid, feerate_per_kw: u32, conte
        }
 }
 
+/// Gets the witnessScript for an anchor output from the funding public key.
+/// The witness in the spending input must be:
+/// <BIP 143 funding_signature>
+/// After 16 blocks of confirmation, an alternative satisfying witness could be:
+/// <>
+#[inline]
+pub(crate) fn get_anchor_redeemscript(funding_pubkey: &PublicKey) -> Script {
+       Builder::new().push_slice(&funding_pubkey.serialize()[..])
+               .push_opcode(opcodes::all::OP_CHECKSIG)
+               .push_opcode(opcodes::all::OP_IFDUP)
+               .push_opcode(opcodes::all::OP_NOTIF)
+               .push_int(16)
+               .push_opcode(opcodes::all::OP_CSV)
+               .push_opcode(opcodes::all::OP_ENDIF)
+               .into_script()
+}
+
 /// Per-channel data used to build transactions in conjunction with the per-commitment data (CommitmentTransaction).
 /// The fields are organized by holder/counterparty.
 ///