f - Add ShutdownScript::is_compatible

diff --git a/lightning/src/ln/script.rs b/lightning/src/ln/script.rs
index a01866de679e8762bce76b9fe3a7df4fe666b301..4ad0af02b908599c8e95550b354ca1c6bb21ef52 100644 (file)
--- a/lightning/src/ln/script.rs
+++ b/lightning/src/ln/script.rs
@@ -105,6 +105,26 @@ impl ShutdownScript {
                        ShutdownScriptImpl::Bolt2(_) => None,
                }
        }
+
+       /// Returns whether the shutdown script is compatible with the features as defined by BOLT #2.
+       ///
+       /// Specifically, checks for compliance with feature `option_shutdown_anysegwit`.
+       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 {
@@ -119,10 +139,8 @@ impl TryFrom<(Script, &InitFeatures)> for ShutdownScript {
        type Error = InvalidShutdownScript;
 
        fn try_from((script, features): (Script, &InitFeatures)) -> Result<Self, Self::Error> {
-               if script.is_p2pkh() || script.is_p2sh() || script.is_v0_p2wpkh() || script.is_v0_p2wsh() {
+               if is_bolt2_compliant(&script, features) {
                        Ok(Self(ShutdownScriptImpl::Bolt2(script)))
-               } else if features.supports_shutdown_anysegwit() && script.is_witness_program() && script.as_bytes()[0] != SEGWIT_V0.into_u8() {
-                       Ok(Self(ShutdownScriptImpl::Bolt2(script)))  // option_shutdown_anysegwit
                } else {
                        Err(InvalidShutdownScript(script))
                }
@@ -147,7 +165,9 @@ mod shutdown_script_tests {
        use bitcoin::blockdata::script::{Builder, Script};
        use bitcoin::secp256k1::Secp256k1;
        use bitcoin::secp256k1::key::{PublicKey, SecretKey};
+       use ln::features::InitFeatures;
        use std::convert::TryFrom;
+       use core::num::NonZeroU8;
 
        fn pubkey() -> bitcoin::util::ecdsa::PublicKey {
                let secp_ctx = Secp256k1::signing_only();
@@ -173,6 +193,8 @@ mod shutdown_script_tests {
                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);
        }
 
@@ -182,6 +204,8 @@ mod shutdown_script_tests {
                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());
        }
@@ -192,6 +216,8 @@ mod shutdown_script_tests {
                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());
        }
@@ -202,6 +228,8 @@ mod shutdown_script_tests {
                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());
        }
@@ -212,10 +240,24 @@ mod shutdown_script_tests {
                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]);
+               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]);
@@ -223,8 +265,14 @@ mod shutdown_script_tests {
        }
 
        #[test]
-       fn fails_from_invalid_segwit_v0_program() {
+       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 witness_program = Script::new_witness_program(u5::try_from_u8(16).unwrap(), &[0; 42]);
+               assert!(ShutdownScript::try_from(witness_program).is_err());
+       }
 }