Follow-up nits from #1199 (phantom node support)

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

diff --git a/lightning/src/util/scid_utils.rs b/lightning/src/util/scid_utils.rs
index f9dfd1b0320cb8308d91489928f3bdc1503504e0..11b8d0c95e098761ad6cfdd86e9ad717a48fcd27 100644 (file)
--- a/lightning/src/util/scid_utils.rs
+++ b/lightning/src/util/scid_utils.rs
@@ -104,18 +104,15 @@ pub(crate) mod fake_scid {
                        let rand_bytes = keys_manager.get_secure_random_bytes();
 
                        let segwit_activation_height = segwit_activation_height(genesis_hash);
-                       let mut valid_block_range = if highest_seen_blockheight > segwit_activation_height {
-                               highest_seen_blockheight - segwit_activation_height
-                       } else {
-                               1
-                       };
+                       let mut blocks_since_segwit_activation = highest_seen_blockheight.saturating_sub(segwit_activation_height);
+
                        // We want to ensure that this fake channel won't conflict with any transactions we haven't
                        // seen yet, in case `highest_seen_blockheight` is updated before we get full information
                        // about transactions confirmed in the given block.
-                       if valid_block_range > BLOCKS_PER_MONTH { valid_block_range -= BLOCKS_PER_MONTH; }
+                       blocks_since_segwit_activation = blocks_since_segwit_activation.saturating_sub(BLOCKS_PER_MONTH);
 
                        let rand_for_height = u32::from_be_bytes(rand_bytes[..4].try_into().unwrap());
-                       let fake_scid_height = segwit_activation_height + rand_for_height % valid_block_range;
+                       let fake_scid_height = segwit_activation_height + rand_for_height % (blocks_since_segwit_activation + 1);
 
                        let rand_for_tx_index = u32::from_be_bytes(rand_bytes[4..8].try_into().unwrap());
                        let fake_scid_tx_index = rand_for_tx_index % MAX_TX_INDEX;