Merge pull request #1790 from tnull/2022-10-inbound-user-channel-id-randomization

[rust-lightning] / lightning / src / util / events.rs

diff --git a/lightning/src/util/events.rs b/lightning/src/util/events.rs
index 9818bfc4c8da0eb8fc746a8133d08df84aaaa5d8..a06c7f1e3c0b75ca7bba3562407afb22f5cd158a 100644 (file)
--- a/lightning/src/util/events.rs
+++ b/lightning/src/util/events.rs
@@ -318,11 +318,11 @@ pub enum Event {
                channel_value_satoshis: u64,
                /// The script which should be used in the transaction output.
                output_script: Script,
-               /// The `user_channel_id` value passed in to [`ChannelManager::create_channel`], or 0 for
-               /// an inbound channel.
+               /// The `user_channel_id` value passed in to [`ChannelManager::create_channel`], or a
+               /// random value for an inbound channel.
                ///
                /// [`ChannelManager::create_channel`]: crate::ln::channelmanager::ChannelManager::create_channel
-               user_channel_id: u64,
+               user_channel_id: u128,
        },
        /// Indicates we've received (an offer of) money! Just gotta dig out that payment preimage and
        /// feed it to [`ChannelManager::claim_funds`] to get it....
@@ -612,12 +612,12 @@ pub enum Event {
                /// The `user_channel_id` value passed in to [`ChannelManager::create_channel`] for outbound
                /// channels, or to [`ChannelManager::accept_inbound_channel`] for inbound channels if
                /// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true. Otherwise
-               /// `user_channel_id` will be 0 for an inbound channel.
+               /// `user_channel_id` will be randomized for an inbound channel.
                ///
                /// [`ChannelManager::create_channel`]: crate::ln::channelmanager::ChannelManager::create_channel
                /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
                /// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
-               user_channel_id: u64,
+               user_channel_id: u128,
                /// The node_id of the channel counterparty.
                counterparty_node_id: PublicKey,
                /// The features that this channel will operate with.
@@ -632,13 +632,13 @@ pub enum Event {
                /// The `user_channel_id` value passed in to [`ChannelManager::create_channel`] for outbound
                /// channels, or to [`ChannelManager::accept_inbound_channel`] for inbound channels if
                /// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true. Otherwise
-               /// `user_channel_id` will be 0 for an inbound channel.
+               /// `user_channel_id` will be randomized for an inbound channel.
                /// This will always be zero for objects serialized with LDK versions prior to 0.0.102.
                ///
                /// [`ChannelManager::create_channel`]: crate::ln::channelmanager::ChannelManager::create_channel
                /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
                /// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
-               user_channel_id: u64,
+               user_channel_id: u128,
                /// The reason the channel was closed.
                reason: ClosureReason
        },
@@ -813,10 +813,16 @@ impl Writeable for Event {
                        },
                        &Event::ChannelClosed { ref channel_id, ref user_channel_id, ref reason } => {
                                9u8.write(writer)?;
+                               // `user_channel_id` used to be a single u64 value. In order to remain backwards
+                               // compatible with versions prior to 0.0.113, the u128 is serialized as two
+                               // separate u64 values.
+                               let user_channel_id_low = *user_channel_id as u64;
+                               let user_channel_id_high = (*user_channel_id >> 64) as u64;
                                write_tlv_fields!(writer, {
                                        (0, channel_id, required),
-                                       (1, user_channel_id, required),
-                                       (2, reason, required)
+                                       (1, user_channel_id_low, required),
+                                       (2, reason, required),
+                                       (3, user_channel_id_high, required),
                                });
                        },
                        &Event::DiscardFunding { ref channel_id, ref transaction } => {
@@ -1035,14 +1041,22 @@ impl MaybeReadable for Event {
                                let f = || {
                                        let mut channel_id = [0; 32];
                                        let mut reason = None;
-                                       let mut user_channel_id_opt = None;
+                                       let mut user_channel_id_low_opt: Option<u64> = None;
+                                       let mut user_channel_id_high_opt: Option<u64> = None;
                                        read_tlv_fields!(reader, {
                                                (0, channel_id, required),
-                                               (1, user_channel_id_opt, option),
+                                               (1, user_channel_id_low_opt, option),
                                                (2, reason, ignorable),
+                                               (3, user_channel_id_high_opt, option),
                                        });
                                        if reason.is_none() { return Ok(None); }
-                                       let user_channel_id = if let Some(id) = user_channel_id_opt { id } else { 0 };
+
+                                       // `user_channel_id` used to be a single u64 value. In order to remain
+                                       // backwards compatible with versions prior to 0.0.113, the u128 is serialized
+                                       // as two separate u64 values.
+                                       let user_channel_id = (user_channel_id_low_opt.unwrap_or(0) as u128) +
+                                               ((user_channel_id_high_opt.unwrap_or(0) as u128) << 64);
+
                                        Ok(Some(Event::ChannelClosed { channel_id, user_channel_id, reason: reason.unwrap() }))
                                };
                                f()
@@ -1180,7 +1194,7 @@ impl MaybeReadable for Event {
                        29u8 => {
                                let f = || {
                                        let mut channel_id = [0; 32];
-                                       let mut user_channel_id: u64 = 0;
+                                       let mut user_channel_id: u128 = 0;
                                        let mut counterparty_node_id = OptionDeserWrapper(None);
                                        let mut channel_type = OptionDeserWrapper(None);
                                        read_tlv_fields!(reader, {