+ // Our commitment transaction already has fees allocated to it, so we should take them into
+ // account. We compute its feerate and subtract it from the package target, using the result
+ // as the target feerate for our anchor transaction. Unfortunately, this results in users
+ // overpaying by a small margin since we don't yet know the anchor transaction size, and
+ // avoiding the small overpayment only makes our API even more complex.
+ let commitment_tx_sat_per_1000_weight: u32 = compute_feerate_sat_per_1000_weight(
+ commitment_tx_fee_sat, commitment_tx.weight() as u64,
+ );
+ let anchor_target_feerate_sat_per_1000_weight = core::cmp::max(
+ package_target_feerate_sat_per_1000_weight - commitment_tx_sat_per_1000_weight,
+ FEERATE_FLOOR_SATS_PER_KW,
+ );
+