Separate `ChannelDetails`' outbound capacity from the next HTLC max

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

diff --git a/lightning/src/ln/channel.rs b/lightning/src/ln/channel.rs
index b0551bf8323f1617f7cba4c991c783221c778c46..afb1de43f1c296f771296d7ea7e728b4138e3fca 100644 (file)
--- a/lightning/src/ln/channel.rs
+++ b/lightning/src/ln/channel.rs
@@ -2330,23 +2330,30 @@ impl<Signer: Sign> Channel<Signer> {
                stats
        }
 
-       /// Get the available (ie not including pending HTLCs) inbound and outbound balance in msat.
+       /// Get the available (ie not including pending HTLCs) inbound and outbound balance, plus the
+       /// amount available for a single HTLC send, all in msat.
        /// Doesn't bother handling the
        /// if-we-removed-it-already-but-haven't-fully-resolved-they-can-still-send-an-inbound-HTLC
        /// corner case properly.
        /// The channel reserve is subtracted from each balance.
        /// See also [`Channel::get_balance_msat`]
-       pub fn get_inbound_outbound_available_balance_msat(&self) -> (u64, u64) {
+       pub fn get_inbound_outbound_available_balance_msat(&self) -> (u64, u64, u64) {
                // Note that we have to handle overflow due to the above case.
+               let outbound_stats = self.get_outbound_pending_htlc_stats(None);
+               let outbound_capacity_msat = cmp::max(self.value_to_self_msat as i64
+                               - outbound_stats.pending_htlcs_value_msat as i64
+                               - self.counterparty_selected_channel_reserve_satoshis.unwrap_or(0) as i64 * 1000,
+                       0) as u64;
                (
                        cmp::max(self.channel_value_satoshis as i64 * 1000
                                - self.value_to_self_msat as i64
                                - self.get_inbound_pending_htlc_stats(None).pending_htlcs_value_msat as i64
                                - self.holder_selected_channel_reserve_satoshis as i64 * 1000,
                        0) as u64,
-                       cmp::max(self.value_to_self_msat as i64
-                               - self.get_outbound_pending_htlc_stats(None).pending_htlcs_value_msat as i64
-                               - self.counterparty_selected_channel_reserve_satoshis.unwrap_or(0) as i64 * 1000,
+                       outbound_capacity_msat,
+                       cmp::max(cmp::min(outbound_capacity_msat as i64,
+                               self.counterparty_max_htlc_value_in_flight_msat as i64
+                                       - outbound_stats.pending_htlcs_value_msat as i64),
                        0) as u64
                )
        }