1 //! Abstractions for scripts used in the Lightning Network.
3 use bitcoin::bech32::u5;
4 use bitcoin::blockdata::opcodes::all::OP_PUSHBYTES_0 as SEGWIT_V0;
5 use bitcoin::blockdata::script::Script;
6 use bitcoin::hashes::Hash;
7 use bitcoin::hash_types::{PubkeyHash, ScriptHash, WPubkeyHash, WScriptHash};
8 use bitcoin::secp256k1::key::PublicKey;
10 use ln::features::InitFeatures;
11 use ln::msgs::DecodeError;
12 use util::ser::{Readable, Writeable, Writer};
14 use std::convert::TryFrom;
16 use core::num::NonZeroU8;
18 /// A script pubkey for shutting down a channel as defined by [BOLT #2].
20 /// [BOLT #2]: https://github.com/lightningnetwork/lightning-rfc/blob/master/02-peer-protocol.md
22 pub struct ShutdownScript(ShutdownScriptImpl);
24 /// An error occurring when converting from [`Script`] to [`ShutdownScript`].
26 pub struct InvalidShutdownScript(Script);
29 enum ShutdownScriptImpl {
30 /// [`PublicKey`] used to form a P2WPKH script pubkey. Used to support backward-compatible
34 /// [`Script`] adhering to a script pubkey format specified in BOLT #2.
38 impl Writeable for ShutdownScript {
39 fn write<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
43 fn serialized_length(&self) -> usize {
44 self.0.serialized_length()
48 impl Readable for ShutdownScript {
49 fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
50 Ok(ShutdownScript(ShutdownScriptImpl::read(r)?))
54 impl_writeable_tlv_based_enum!(ShutdownScriptImpl, ;
60 /// Generates a P2WPKH script pubkey from the given [`PublicKey`].
61 pub(crate) fn new_p2wpkh_from_pubkey(pubkey: PublicKey) -> Self {
62 Self(ShutdownScriptImpl::Legacy(pubkey))
65 /// Generates a P2PKH script pubkey from the given [`PubkeyHash`].
66 pub fn new_p2pkh(pubkey_hash: &PubkeyHash) -> Self {
67 Self(ShutdownScriptImpl::Bolt2(Script::new_p2pkh(pubkey_hash)))
70 /// Generates a P2SH script pubkey from the given [`ScriptHash`].
71 pub fn new_p2sh(script_hash: &ScriptHash) -> Self {
72 Self(ShutdownScriptImpl::Bolt2(Script::new_p2sh(script_hash)))
75 /// Generates a P2WPKH script pubkey from the given [`WPubkeyHash`].
76 pub fn new_p2wpkh(pubkey_hash: &WPubkeyHash) -> Self {
77 Self(ShutdownScriptImpl::Bolt2(Script::new_v0_wpkh(pubkey_hash)))
80 /// Generates a P2WSH script pubkey from the given [`WScriptHash`].
81 pub fn new_p2wsh(script_hash: &WScriptHash) -> Self {
82 Self(ShutdownScriptImpl::Bolt2(Script::new_v0_wsh(script_hash)))
85 /// Generates a P2WSH script pubkey from the given segwit version and program.
89 /// This function may panic if given a segwit program with an invalid length.
90 pub fn new_witness_program(version: NonZeroU8, program: &[u8]) -> Self {
91 let version = u5::try_from_u8(version.get()).expect("Invalid segwit version");
92 let script = Script::new_witness_program(version, program);
93 Self::try_from(script).expect("Invalid segwit program")
96 /// Converts the shutdown script into the underlying [`Script`].
97 pub fn into_inner(self) -> Script {
101 /// Returns the [`PublicKey`] used for a P2WPKH shutdown script if constructed directly from it.
102 pub fn as_legacy_pubkey(&self) -> Option<&PublicKey> {
104 ShutdownScriptImpl::Legacy(pubkey) => Some(pubkey),
105 ShutdownScriptImpl::Bolt2(_) => None,
109 /// Returns whether the shutdown script is compatible with the features as defined by BOLT #2.
111 /// Specifically, checks for compliance with feature `option_shutdown_anysegwit`.
112 pub fn is_compatible(&self, features: &InitFeatures) -> bool {
114 ShutdownScriptImpl::Legacy(_) => true,
115 ShutdownScriptImpl::Bolt2(script) => is_bolt2_compliant(script, features),
120 fn is_bolt2_compliant(script: &Script, features: &InitFeatures) -> bool {
121 if script.is_p2pkh() || script.is_p2sh() || script.is_v0_p2wpkh() || script.is_v0_p2wsh() {
123 } else if features.supports_shutdown_anysegwit() {
124 script.is_witness_program() && script.as_bytes()[0] != SEGWIT_V0.into_u8()
130 impl TryFrom<Script> for ShutdownScript {
131 type Error = InvalidShutdownScript;
133 fn try_from(script: Script) -> Result<Self, Self::Error> {
134 Self::try_from((script, &InitFeatures::known()))
138 impl TryFrom<(Script, &InitFeatures)> for ShutdownScript {
139 type Error = InvalidShutdownScript;
141 fn try_from((script, features): (Script, &InitFeatures)) -> Result<Self, Self::Error> {
142 if is_bolt2_compliant(&script, features) {
143 Ok(Self(ShutdownScriptImpl::Bolt2(script)))
145 Err(InvalidShutdownScript(script))
150 impl Into<Script> for ShutdownScript {
151 fn into(self) -> Script {
153 ShutdownScriptImpl::Legacy(pubkey) =>
154 Script::new_v0_wpkh(&WPubkeyHash::hash(&pubkey.serialize())),
155 ShutdownScriptImpl::Bolt2(script_pubkey) => script_pubkey,
161 mod shutdown_script_tests {
162 use super::ShutdownScript;
163 use bitcoin::bech32::u5;
164 use bitcoin::blockdata::opcodes;
165 use bitcoin::blockdata::script::{Builder, Script};
166 use bitcoin::secp256k1::Secp256k1;
167 use bitcoin::secp256k1::key::{PublicKey, SecretKey};
168 use ln::features::InitFeatures;
169 use std::convert::TryFrom;
170 use core::num::NonZeroU8;
172 fn pubkey() -> bitcoin::util::ecdsa::PublicKey {
173 let secp_ctx = Secp256k1::signing_only();
174 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();
175 bitcoin::util::ecdsa::PublicKey::new(PublicKey::from_secret_key(&secp_ctx, &secret_key))
178 fn redeem_script() -> Script {
179 let pubkey = pubkey();
181 .push_opcode(opcodes::all::OP_PUSHNUM_2)
184 .push_opcode(opcodes::all::OP_PUSHNUM_2)
185 .push_opcode(opcodes::all::OP_CHECKMULTISIG)
190 fn generates_p2wpkh_from_pubkey() {
191 let pubkey = pubkey();
192 let pubkey_hash = pubkey.wpubkey_hash().unwrap();
193 let p2wpkh_script = Script::new_v0_wpkh(&pubkey_hash);
195 let shutdown_script = ShutdownScript::new_p2wpkh_from_pubkey(pubkey.key);
196 assert!(shutdown_script.is_compatible(&InitFeatures::known()));
197 assert!(shutdown_script.is_compatible(&InitFeatures::known().clear_shutdown_anysegwit()));
198 assert_eq!(shutdown_script.into_inner(), p2wpkh_script);
202 fn generates_p2pkh_from_pubkey_hash() {
203 let pubkey_hash = pubkey().pubkey_hash();
204 let p2pkh_script = Script::new_p2pkh(&pubkey_hash);
206 let shutdown_script = ShutdownScript::new_p2pkh(&pubkey_hash);
207 assert!(shutdown_script.is_compatible(&InitFeatures::known()));
208 assert!(shutdown_script.is_compatible(&InitFeatures::known().clear_shutdown_anysegwit()));
209 assert_eq!(shutdown_script.into_inner(), p2pkh_script);
210 assert!(ShutdownScript::try_from(p2pkh_script).is_ok());
214 fn generates_p2sh_from_script_hash() {
215 let script_hash = redeem_script().script_hash();
216 let p2sh_script = Script::new_p2sh(&script_hash);
218 let shutdown_script = ShutdownScript::new_p2sh(&script_hash);
219 assert!(shutdown_script.is_compatible(&InitFeatures::known()));
220 assert!(shutdown_script.is_compatible(&InitFeatures::known().clear_shutdown_anysegwit()));
221 assert_eq!(shutdown_script.into_inner(), p2sh_script);
222 assert!(ShutdownScript::try_from(p2sh_script).is_ok());
226 fn generates_p2wpkh_from_pubkey_hash() {
227 let pubkey_hash = pubkey().wpubkey_hash().unwrap();
228 let p2wpkh_script = Script::new_v0_wpkh(&pubkey_hash);
230 let shutdown_script = ShutdownScript::new_p2wpkh(&pubkey_hash);
231 assert!(shutdown_script.is_compatible(&InitFeatures::known()));
232 assert!(shutdown_script.is_compatible(&InitFeatures::known().clear_shutdown_anysegwit()));
233 assert_eq!(shutdown_script.into_inner(), p2wpkh_script);
234 assert!(ShutdownScript::try_from(p2wpkh_script).is_ok());
238 fn generates_p2wsh_from_script_hash() {
239 let script_hash = redeem_script().wscript_hash();
240 let p2wsh_script = Script::new_v0_wsh(&script_hash);
242 let shutdown_script = ShutdownScript::new_p2wsh(&script_hash);
243 assert!(shutdown_script.is_compatible(&InitFeatures::known()));
244 assert!(shutdown_script.is_compatible(&InitFeatures::known().clear_shutdown_anysegwit()));
245 assert_eq!(shutdown_script.into_inner(), p2wsh_script);
246 assert!(ShutdownScript::try_from(p2wsh_script).is_ok());
250 fn generates_segwit_from_non_v0_witness_program() {
251 let version = u5::try_from_u8(16).unwrap();
252 let witness_program = Script::new_witness_program(version, &[0; 40]);
254 let version = NonZeroU8::new(version.to_u8()).unwrap();
255 let shutdown_script = ShutdownScript::new_witness_program(version, &[0; 40]);
256 assert!(shutdown_script.is_compatible(&InitFeatures::known()));
257 assert!(!shutdown_script.is_compatible(&InitFeatures::known().clear_shutdown_anysegwit()));
258 assert_eq!(shutdown_script.into_inner(), witness_program);
262 fn fails_from_unsupported_script() {
263 let op_return = Script::new_op_return(&[0; 42]);
264 assert!(ShutdownScript::try_from(op_return).is_err());
268 fn fails_from_invalid_segwit_v0_witness_program() {
269 let witness_program = Script::new_witness_program(u5::try_from_u8(0).unwrap(), &[0; 2]);
270 assert!(ShutdownScript::try_from(witness_program).is_err());
274 fn fails_from_invalid_segwit_non_v0_witness_program() {
275 let witness_program = Script::new_witness_program(u5::try_from_u8(16).unwrap(), &[0; 42]);
276 assert!(ShutdownScript::try_from(witness_program).is_err());