1 //! Abstractions for scripts used in the Lightning Network.
3 use bitcoin::blockdata::opcodes::all::OP_PUSHBYTES_0 as SEGWIT_V0;
4 use bitcoin::blockdata::script::{Script, ScriptBuf};
5 use bitcoin::hashes::Hash;
6 use bitcoin::hash_types::{WPubkeyHash, WScriptHash};
7 use bitcoin::secp256k1::PublicKey;
8 use bitcoin::address::WitnessProgram;
10 use crate::ln::channelmanager;
11 use crate::ln::features::InitFeatures;
12 use crate::ln::msgs::DecodeError;
13 use crate::util::ser::{Readable, Writeable, Writer};
17 #[allow(unused_imports)]
18 use crate::prelude::*;
20 /// A script pubkey for shutting down a channel as defined by [BOLT #2].
22 /// [BOLT #2]: https://github.com/lightning/bolts/blob/master/02-peer-protocol.md
23 #[derive(Clone, PartialEq, Eq)]
24 pub struct ShutdownScript(ShutdownScriptImpl);
26 /// An error occurring when converting from [`ScriptBuf`] to [`ShutdownScript`].
27 #[derive(Clone, Debug)]
28 pub struct InvalidShutdownScript {
29 /// The script that did not meet the requirements from [BOLT #2].
31 /// [BOLT #2]: https://github.com/lightning/bolts/blob/master/02-peer-protocol.md
35 #[derive(Clone, PartialEq, Eq)]
36 enum ShutdownScriptImpl {
37 /// [`PublicKey`] used to form a P2WPKH script pubkey. Used to support backward-compatible
41 /// [`ScriptBuf`] adhering to a script pubkey format specified in BOLT #2.
45 impl Writeable for ShutdownScript {
46 fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
51 impl Readable for ShutdownScript {
52 fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
53 Ok(ShutdownScript(ShutdownScriptImpl::read(r)?))
57 impl_writeable_tlv_based_enum!(ShutdownScriptImpl, ;
63 /// Generates a P2WPKH script pubkey from the given [`PublicKey`].
64 pub(crate) fn new_p2wpkh_from_pubkey(pubkey: PublicKey) -> Self {
65 Self(ShutdownScriptImpl::Legacy(pubkey))
68 /// Generates a P2WPKH script pubkey from the given [`WPubkeyHash`].
69 pub fn new_p2wpkh(pubkey_hash: &WPubkeyHash) -> Self {
70 Self(ShutdownScriptImpl::Bolt2(ScriptBuf::new_v0_p2wpkh(pubkey_hash)))
73 /// Generates a P2WSH script pubkey from the given [`WScriptHash`].
74 pub fn new_p2wsh(script_hash: &WScriptHash) -> Self {
75 Self(ShutdownScriptImpl::Bolt2(ScriptBuf::new_v0_p2wsh(script_hash)))
78 /// Generates a witness script pubkey from the given segwit version and program.
80 /// Note for version-zero witness scripts you must use [`ShutdownScript::new_p2wpkh`] or
81 /// [`ShutdownScript::new_p2wsh`] instead.
85 /// This function may return an error if `program` is invalid for the segwit `version`.
86 pub fn new_witness_program(witness_program: &WitnessProgram) -> Result<Self, InvalidShutdownScript> {
87 Self::try_from(ScriptBuf::new_witness_program(witness_program))
90 /// Converts the shutdown script into the underlying [`ScriptBuf`].
91 pub fn into_inner(self) -> ScriptBuf {
95 /// Returns the [`PublicKey`] used for a P2WPKH shutdown script if constructed directly from it.
96 pub fn as_legacy_pubkey(&self) -> Option<&PublicKey> {
98 ShutdownScriptImpl::Legacy(pubkey) => Some(pubkey),
99 ShutdownScriptImpl::Bolt2(_) => None,
103 /// Returns whether the shutdown script is compatible with the features as defined by BOLT #2.
105 /// Specifically, checks for compliance with feature `option_shutdown_anysegwit`.
106 pub fn is_compatible(&self, features: &InitFeatures) -> bool {
108 ShutdownScriptImpl::Legacy(_) => true,
109 ShutdownScriptImpl::Bolt2(script) => is_bolt2_compliant(script, features),
114 /// Check if a given script is compliant with BOLT 2's shutdown script requirements for the given
115 /// counterparty features.
116 pub(crate) fn is_bolt2_compliant(script: &Script, features: &InitFeatures) -> bool {
117 if script.is_p2pkh() || script.is_p2sh() || script.is_v0_p2wpkh() || script.is_v0_p2wsh() {
119 } else if features.supports_shutdown_anysegwit() {
120 script.is_witness_program() && script.as_bytes()[0] != SEGWIT_V0.to_u8()
126 // Note that this is only for our own shutdown scripts. Counterparties are still allowed to send us
127 // non-witness shutdown scripts which this rejects.
128 impl TryFrom<ScriptBuf> for ShutdownScript {
129 type Error = InvalidShutdownScript;
131 fn try_from(script: ScriptBuf) -> Result<Self, Self::Error> {
132 Self::try_from((script, &channelmanager::provided_init_features(&crate::util::config::UserConfig::default())))
136 // Note that this is only for our own shutdown scripts. Counterparties are still allowed to send us
137 // non-witness shutdown scripts which this rejects.
138 impl TryFrom<(ScriptBuf, &InitFeatures)> for ShutdownScript {
139 type Error = InvalidShutdownScript;
141 fn try_from((script, features): (ScriptBuf, &InitFeatures)) -> Result<Self, Self::Error> {
142 if is_bolt2_compliant(&script, features) && script.is_witness_program() {
143 Ok(Self(ShutdownScriptImpl::Bolt2(script)))
145 Err(InvalidShutdownScript { script })
150 impl Into<ScriptBuf> for ShutdownScript {
151 fn into(self) -> ScriptBuf {
153 ShutdownScriptImpl::Legacy(pubkey) =>
154 ScriptBuf::new_v0_p2wpkh(&WPubkeyHash::hash(&pubkey.serialize())),
155 ShutdownScriptImpl::Bolt2(script_pubkey) => script_pubkey,
160 impl core::fmt::Display for ShutdownScript{
161 fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
163 ShutdownScriptImpl::Legacy(_) => self.clone().into_inner().fmt(f),
164 ShutdownScriptImpl::Bolt2(script) => script.fmt(f),
170 mod shutdown_script_tests {
171 use super::ShutdownScript;
173 use bitcoin::address::{WitnessProgram, WitnessVersion};
174 use bitcoin::blockdata::opcodes;
175 use bitcoin::blockdata::script::{Builder, ScriptBuf};
176 use bitcoin::secp256k1::Secp256k1;
177 use bitcoin::secp256k1::{PublicKey, SecretKey};
179 use crate::ln::features::InitFeatures;
180 use crate::prelude::*;
182 fn pubkey() -> bitcoin::key::PublicKey {
183 let secp_ctx = Secp256k1::signing_only();
184 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();
185 bitcoin::key::PublicKey::new(PublicKey::from_secret_key(&secp_ctx, &secret_key))
188 fn redeem_script() -> ScriptBuf {
189 let pubkey = pubkey();
191 .push_opcode(opcodes::all::OP_PUSHNUM_2)
194 .push_opcode(opcodes::all::OP_PUSHNUM_2)
195 .push_opcode(opcodes::all::OP_CHECKMULTISIG)
199 fn any_segwit_features() -> InitFeatures {
200 let mut features = InitFeatures::empty();
201 features.set_shutdown_any_segwit_optional();
206 fn generates_p2wpkh_from_pubkey() {
207 let pubkey = pubkey();
208 let pubkey_hash = pubkey.wpubkey_hash().unwrap();
209 let p2wpkh_script = ScriptBuf::new_v0_p2wpkh(&pubkey_hash);
211 let shutdown_script = ShutdownScript::new_p2wpkh_from_pubkey(pubkey.inner);
212 assert!(shutdown_script.is_compatible(&any_segwit_features()));
213 assert!(shutdown_script.is_compatible(&InitFeatures::empty()));
214 assert_eq!(shutdown_script.into_inner(), p2wpkh_script);
218 fn generates_p2wpkh_from_pubkey_hash() {
219 let pubkey_hash = pubkey().wpubkey_hash().unwrap();
220 let p2wpkh_script = ScriptBuf::new_v0_p2wpkh(&pubkey_hash);
222 let shutdown_script = ShutdownScript::new_p2wpkh(&pubkey_hash);
223 assert!(shutdown_script.is_compatible(&any_segwit_features()));
224 assert!(shutdown_script.is_compatible(&InitFeatures::empty()));
225 assert_eq!(shutdown_script.into_inner(), p2wpkh_script);
226 assert!(ShutdownScript::try_from(p2wpkh_script).is_ok());
230 fn generates_p2wsh_from_script_hash() {
231 let script_hash = redeem_script().wscript_hash();
232 let p2wsh_script = ScriptBuf::new_v0_p2wsh(&script_hash);
234 let shutdown_script = ShutdownScript::new_p2wsh(&script_hash);
235 assert!(shutdown_script.is_compatible(&any_segwit_features()));
236 assert!(shutdown_script.is_compatible(&InitFeatures::empty()));
237 assert_eq!(shutdown_script.into_inner(), p2wsh_script);
238 assert!(ShutdownScript::try_from(p2wsh_script).is_ok());
242 fn generates_segwit_from_non_v0_witness_program() {
243 let witness_program = WitnessProgram::new(WitnessVersion::V16, &[0; 40]).unwrap();
244 let script = ScriptBuf::new_witness_program(&witness_program);
245 let shutdown_script = ShutdownScript::new_witness_program(&witness_program).unwrap();
246 assert!(shutdown_script.is_compatible(&any_segwit_features()));
247 assert!(!shutdown_script.is_compatible(&InitFeatures::empty()));
248 assert_eq!(shutdown_script.into_inner(), script);
252 fn fails_from_unsupported_script() {
253 let op_return = ScriptBuf::new_op_return(&[0; 42]);
254 assert!(ShutdownScript::try_from(op_return).is_err());