Add support for the SCIDAlias feature bit in incoming channels

[rust-lightning] / lightning / src / ln / channel.rs

diff --git a/lightning/src/ln/channel.rs b/lightning/src/ln/channel.rs
index e1f292b76736b987c0e375d863f594c3beaf40d4..0bba70e5e20ef306a3ba649eb29bf7ad769a3f21 100644 (file)
--- a/lightning/src/ln/channel.rs
+++ b/lightning/src/ln/channel.rs
@@ -1009,6 +1009,7 @@ impl<Signer: Sign> Channel<Signer> {
                      L::Target: Logger,
        {
                let opt_anchors = false; // TODO - should be based on features
+               let announced_channel = if (msg.channel_flags & 1) == 1 { true } else { false };
 
                // First check the channel type is known, failing before we do anything else if we don't
                // support this channel type.
@@ -1016,8 +1017,18 @@ impl<Signer: Sign> Channel<Signer> {
                        if channel_type.supports_any_optional_bits() {
                                return Err(ChannelError::Close("Channel Type field contained optional bits - this is not allowed".to_owned()));
                        }
-                       if *channel_type != ChannelTypeFeatures::only_static_remote_key() {
-                               return Err(ChannelError::Close("Channel Type was not understood".to_owned()));
+                       // We currently only allow two channel types, so write it all out here - we allow
+                       // `only_static_remote_key` in all contexts, and further allow
+                       // `static_remote_key|scid_privacy` if the channel is not publicly announced.
+                       let mut allowed_type = ChannelTypeFeatures::only_static_remote_key();
+                       if *channel_type != allowed_type {
+                               allowed_type.set_scid_privacy_required();
+                               if *channel_type != allowed_type {
+                                       return Err(ChannelError::Close("Channel Type was not understood".to_owned()));
+                               }
+                               if announced_channel {
+                                       return Err(ChannelError::Close("SCID Alias/Privacy Channel Type cannot be set on a public channel".to_owned()));
+                               }
                        }
                        channel_type.clone()
                } else {
@@ -1098,14 +1109,13 @@ impl<Signer: Sign> Channel<Signer> {
 
                // Convert things into internal flags and prep our state:
 
-               let announce = if (msg.channel_flags & 1) == 1 { true } else { false };
                if config.peer_channel_config_limits.force_announced_channel_preference {
-                       if local_config.announced_channel != announce {
+                       if local_config.announced_channel != announced_channel {
                                return Err(ChannelError::Close("Peer tried to open channel but their announcement preference is different from ours".to_owned()));
                        }
                }
                // we either accept their preference or the preferences match
-               local_config.announced_channel = announce;
+               local_config.announced_channel = announced_channel;
 
                let holder_selected_channel_reserve_satoshis = Channel::<Signer>::get_holder_selected_channel_reserve_satoshis(msg.funding_satoshis);
                if holder_selected_channel_reserve_satoshis < MIN_CHAN_DUST_LIMIT_SATOSHIS {