Merge pull request #440 from TheBlueMatt/2020-01-feature-sanity

Fix a bug in required feature checks

diff --git a/lightning/src/ln/features.rs b/lightning/src/ln/features.rs
index dd0b7fa1a82aba540a259bd18ede2b5156c9eef1..61a862c0c55c71bb62975fc8dd4360a1e3f7f5bf 100644 (file)
--- a/lightning/src/ln/features.rs
+++ b/lightning/src/ln/features.rs
@@ -187,8 +187,14 @@ impl<T: sealed::Context> Features<T> {
        pub(crate) fn requires_unknown_bits(&self) -> bool {
                self.flags.iter().enumerate().any(|(idx, &byte)| {
                        (match idx {
-                               0 => (byte & 0b00010100),
+                               // Unknown bits are even bits which we don't understand, we list ones which we do
+                               // here:
+                               // unknown, upfront_shutdown_script, unknown (actually initial_routing_sync, but it
+                               // is only valid as an optional feature), and data_loss_protect:
+                               0 => (byte & 0b01000100),
+                               // unknown, unknown, unknown, var_onion_optin:
                                1 => (byte & 0b01010100),
+                               // fallback, all even bits set:
                                _ => (byte & 0b01010101),
                        }) != 0
                })
@@ -197,7 +203,10 @@ impl<T: sealed::Context> Features<T> {
        pub(crate) fn supports_unknown_bits(&self) -> bool {
                self.flags.iter().enumerate().any(|(idx, &byte)| {
                        (match idx {
+                               // unknown, upfront_shutdown_script, initial_routing_sync (is only valid as an
+                               // optional feature), and data_loss_protect:
                                0 => (byte & 0b11000100),
+                               // unknown, unknown, unknown, var_onion_optin:
                                1 => (byte & 0b11111100),
                                _ => byte,
                        }) != 0
@@ -284,3 +293,41 @@ impl<R: ::std::io::Read, T: sealed::Context> Readable<R> for Features<T> {
                })
        }
 }
+
+#[cfg(test)]
+mod tests {
+       use super::{ChannelFeatures, InitFeatures, NodeFeatures};
+
+       #[test]
+       fn sanity_test_our_features() {
+               assert!(!ChannelFeatures::supported().requires_unknown_bits());
+               assert!(!ChannelFeatures::supported().supports_unknown_bits());
+               assert!(!InitFeatures::supported().requires_unknown_bits());
+               assert!(!InitFeatures::supported().supports_unknown_bits());
+               assert!(!NodeFeatures::supported().requires_unknown_bits());
+               assert!(!NodeFeatures::supported().supports_unknown_bits());
+
+               assert!(InitFeatures::supported().supports_upfront_shutdown_script());
+               assert!(NodeFeatures::supported().supports_upfront_shutdown_script());
+
+               assert!(InitFeatures::supported().supports_data_loss_protect());
+               assert!(NodeFeatures::supported().supports_data_loss_protect());
+
+               assert!(InitFeatures::supported().supports_variable_length_onion());
+               assert!(NodeFeatures::supported().supports_variable_length_onion());
+
+               let mut init_features = InitFeatures::supported();
+               init_features.set_initial_routing_sync();
+               assert!(!init_features.requires_unknown_bits());
+               assert!(!init_features.supports_unknown_bits());
+       }
+
+       #[test]
+       fn sanity_test_unkown_bits_testing() {
+               let mut features = ChannelFeatures::supported();
+               features.set_require_unknown_bits();
+               assert!(features.requires_unknown_bits());
+               features.clear_require_unknown_bits();
+               assert!(!features.requires_unknown_bits());
+       }
+}