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use bitcoin::blockdata::opcodes::all::OP_PUSHBYTES_0 as SEGWIT_V0;
use bitcoin::blockdata::script::{Builder, Script};
use bitcoin::hashes::Hash;
use bitcoin::hash_types::{PubkeyHash, ScriptHash, WPubkeyHash, WScriptHash};
use bitcoin::secp256k1::key::PublicKey;
use ln::features::InitFeatures;
use ln::msgs::DecodeError;
use util::ser::{Readable, Writeable, Writer};
use core::convert::TryFrom;
use core::num::NonZeroU8;
use io;
#[derive(Clone)]
pub struct ShutdownScript(ShutdownScriptImpl);
#[derive(Debug)]
pub struct InvalidShutdownScript {
pub script: Script
}
#[derive(Clone)]
enum ShutdownScriptImpl {
Legacy(PublicKey),
Bolt2(Script),
}
impl Writeable for ShutdownScript {
fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
self.0.write(w)
}
fn serialized_length(&self) -> usize {
self.0.serialized_length()
}
}
impl Readable for ShutdownScript {
fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
Ok(ShutdownScript(ShutdownScriptImpl::read(r)?))
}
}
impl_writeable_tlv_based_enum!(ShutdownScriptImpl, ;
(0, Legacy),
(1, Bolt2),
);
impl ShutdownScript {
pub(crate) fn new_p2wpkh_from_pubkey(pubkey: PublicKey) -> Self {
Self(ShutdownScriptImpl::Legacy(pubkey))
}
pub fn new_p2pkh(pubkey_hash: &PubkeyHash) -> Self {
Self(ShutdownScriptImpl::Bolt2(Script::new_p2pkh(pubkey_hash)))
}
pub fn new_p2sh(script_hash: &ScriptHash) -> Self {
Self(ShutdownScriptImpl::Bolt2(Script::new_p2sh(script_hash)))
}
pub fn new_p2wpkh(pubkey_hash: &WPubkeyHash) -> Self {
Self(ShutdownScriptImpl::Bolt2(Script::new_v0_wpkh(pubkey_hash)))
}
pub fn new_p2wsh(script_hash: &WScriptHash) -> Self {
Self(ShutdownScriptImpl::Bolt2(Script::new_v0_wsh(script_hash)))
}
pub fn new_witness_program(version: NonZeroU8, program: &[u8]) -> Result<Self, InvalidShutdownScript> {
let script = Builder::new()
.push_int(version.get().into())
.push_slice(&program)
.into_script();
Self::try_from(script)
}
pub fn into_inner(self) -> Script {
self.into()
}
pub fn as_legacy_pubkey(&self) -> Option<&PublicKey> {
match &self.0 {
ShutdownScriptImpl::Legacy(pubkey) => Some(pubkey),
ShutdownScriptImpl::Bolt2(_) => None,
}
}
pub fn is_compatible(&self, features: &InitFeatures) -> bool {
match &self.0 {
ShutdownScriptImpl::Legacy(_) => true,
ShutdownScriptImpl::Bolt2(script) => is_bolt2_compliant(script, features),
}
}
}
fn is_bolt2_compliant(script: &Script, features: &InitFeatures) -> bool {
if script.is_p2pkh() || script.is_p2sh() || script.is_v0_p2wpkh() || script.is_v0_p2wsh() {
true
} else if features.supports_shutdown_anysegwit() {
script.is_witness_program() && script.as_bytes()[0] != SEGWIT_V0.into_u8()
} else {
false
}
}
impl TryFrom<Script> for ShutdownScript {
type Error = InvalidShutdownScript;
fn try_from(script: Script) -> Result<Self, Self::Error> {
Self::try_from((script, &InitFeatures::known()))
}
}
impl TryFrom<(Script, &InitFeatures)> for ShutdownScript {
type Error = InvalidShutdownScript;
fn try_from((script, features): (Script, &InitFeatures)) -> Result<Self, Self::Error> {
if is_bolt2_compliant(&script, features) {
Ok(Self(ShutdownScriptImpl::Bolt2(script)))
} else {
Err(InvalidShutdownScript { script })
}
}
}
impl Into<Script> for ShutdownScript {
fn into(self) -> Script {
match self.0 {
ShutdownScriptImpl::Legacy(pubkey) =>
Script::new_v0_wpkh(&WPubkeyHash::hash(&pubkey.serialize())),
ShutdownScriptImpl::Bolt2(script_pubkey) => script_pubkey,
}
}
}
impl core::fmt::Display for ShutdownScript{
fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
match &self.0 {
ShutdownScriptImpl::Legacy(_) => self.clone().into_inner().fmt(f),
ShutdownScriptImpl::Bolt2(script) => script.fmt(f),
}
}
}
#[cfg(test)]
mod shutdown_script_tests {
use super::ShutdownScript;
use bitcoin::bech32::u5;
use bitcoin::blockdata::opcodes;
use bitcoin::blockdata::script::{Builder, Script};
use bitcoin::secp256k1::Secp256k1;
use bitcoin::secp256k1::key::{PublicKey, SecretKey};
use ln::features::InitFeatures;
use core::convert::TryFrom;
use core::num::NonZeroU8;
fn pubkey() -> bitcoin::util::ecdsa::PublicKey {
let secp_ctx = Secp256k1::signing_only();
let secret_key = SecretKey::from_slice(&[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1]).unwrap();
bitcoin::util::ecdsa::PublicKey::new(PublicKey::from_secret_key(&secp_ctx, &secret_key))
}
fn redeem_script() -> Script {
let pubkey = pubkey();
Builder::new()
.push_opcode(opcodes::all::OP_PUSHNUM_2)
.push_key(&pubkey)
.push_key(&pubkey)
.push_opcode(opcodes::all::OP_PUSHNUM_2)
.push_opcode(opcodes::all::OP_CHECKMULTISIG)
.into_script()
}
#[test]
fn generates_p2wpkh_from_pubkey() {
let pubkey = pubkey();
let pubkey_hash = pubkey.wpubkey_hash().unwrap();
let p2wpkh_script = Script::new_v0_wpkh(&pubkey_hash);
let shutdown_script = ShutdownScript::new_p2wpkh_from_pubkey(pubkey.key);
assert!(shutdown_script.is_compatible(&InitFeatures::known()));
assert!(shutdown_script.is_compatible(&InitFeatures::known().clear_shutdown_anysegwit()));
assert_eq!(shutdown_script.into_inner(), p2wpkh_script);
}
#[test]
fn generates_p2pkh_from_pubkey_hash() {
let pubkey_hash = pubkey().pubkey_hash();
let p2pkh_script = Script::new_p2pkh(&pubkey_hash);
let shutdown_script = ShutdownScript::new_p2pkh(&pubkey_hash);
assert!(shutdown_script.is_compatible(&InitFeatures::known()));
assert!(shutdown_script.is_compatible(&InitFeatures::known().clear_shutdown_anysegwit()));
assert_eq!(shutdown_script.into_inner(), p2pkh_script);
assert!(ShutdownScript::try_from(p2pkh_script).is_ok());
}
#[test]
fn generates_p2sh_from_script_hash() {
let script_hash = redeem_script().script_hash();
let p2sh_script = Script::new_p2sh(&script_hash);
let shutdown_script = ShutdownScript::new_p2sh(&script_hash);
assert!(shutdown_script.is_compatible(&InitFeatures::known()));
assert!(shutdown_script.is_compatible(&InitFeatures::known().clear_shutdown_anysegwit()));
assert_eq!(shutdown_script.into_inner(), p2sh_script);
assert!(ShutdownScript::try_from(p2sh_script).is_ok());
}
#[test]
fn generates_p2wpkh_from_pubkey_hash() {
let pubkey_hash = pubkey().wpubkey_hash().unwrap();
let p2wpkh_script = Script::new_v0_wpkh(&pubkey_hash);
let shutdown_script = ShutdownScript::new_p2wpkh(&pubkey_hash);
assert!(shutdown_script.is_compatible(&InitFeatures::known()));
assert!(shutdown_script.is_compatible(&InitFeatures::known().clear_shutdown_anysegwit()));
assert_eq!(shutdown_script.into_inner(), p2wpkh_script);
assert!(ShutdownScript::try_from(p2wpkh_script).is_ok());
}
#[test]
fn generates_p2wsh_from_script_hash() {
let script_hash = redeem_script().wscript_hash();
let p2wsh_script = Script::new_v0_wsh(&script_hash);
let shutdown_script = ShutdownScript::new_p2wsh(&script_hash);
assert!(shutdown_script.is_compatible(&InitFeatures::known()));
assert!(shutdown_script.is_compatible(&InitFeatures::known().clear_shutdown_anysegwit()));
assert_eq!(shutdown_script.into_inner(), p2wsh_script);
assert!(ShutdownScript::try_from(p2wsh_script).is_ok());
}
#[test]
fn generates_segwit_from_non_v0_witness_program() {
let version = u5::try_from_u8(16).unwrap();
let witness_program = Script::new_witness_program(version, &[0; 40]);
let version = NonZeroU8::new(version.to_u8()).unwrap();
let shutdown_script = ShutdownScript::new_witness_program(version, &[0; 40]).unwrap();
assert!(shutdown_script.is_compatible(&InitFeatures::known()));
assert!(!shutdown_script.is_compatible(&InitFeatures::known().clear_shutdown_anysegwit()));
assert_eq!(shutdown_script.into_inner(), witness_program);
}
#[test]
fn fails_from_unsupported_script() {
let op_return = Script::new_op_return(&[0; 42]);
assert!(ShutdownScript::try_from(op_return).is_err());
}
#[test]
fn fails_from_invalid_segwit_version() {
let version = NonZeroU8::new(17).unwrap();
assert!(ShutdownScript::new_witness_program(version, &[0; 40]).is_err());
}
#[test]
fn fails_from_invalid_segwit_v0_witness_program() {
let witness_program = Script::new_witness_program(u5::try_from_u8(0).unwrap(), &[0; 2]);
assert!(ShutdownScript::try_from(witness_program).is_err());
}
#[test]
fn fails_from_invalid_segwit_non_v0_witness_program() {
let version = u5::try_from_u8(16).unwrap();
let witness_program = Script::new_witness_program(version, &[0; 42]);
assert!(ShutdownScript::try_from(witness_program).is_err());
let version = NonZeroU8::new(version.to_u8()).unwrap();
assert!(ShutdownScript::new_witness_program(version, &[0; 42]).is_err());
}
}