Add package.rs file

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

diff --git a/lightning/src/ln/package.rs b/lightning/src/ln/package.rs
new file mode 100644 (file)
index 0000000..c0d735a
--- /dev/null
+++ b/lightning/src/ln/package.rs
@@ -0,0 +1,90 @@
+//! Utilities for computing witnesses weight and feerate computation for onchain operation
+
+use ln::msgs::DecodeError;
+use util::ser::{Readable, Writer, Writeable};
+
+#[derive(PartialEq, Clone, Copy)]
+pub(crate) enum InputDescriptors {
+       RevokedOfferedHTLC,
+       RevokedReceivedHTLC,
+       OfferedHTLC,
+       ReceivedHTLC,
+       RevokedOutput, // either a revoked to_holder output on commitment tx, a revoked HTLC-Timeout output or a revoked HTLC-Success output
+}
+
+impl Writeable for InputDescriptors {
+       fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
+               match self {
+                       &InputDescriptors::RevokedOfferedHTLC => {
+                               writer.write_all(&[0; 1])?;
+                       },
+                       &InputDescriptors::RevokedReceivedHTLC => {
+                               writer.write_all(&[1; 1])?;
+                       },
+                       &InputDescriptors::OfferedHTLC => {
+                               writer.write_all(&[2; 1])?;
+                       },
+                       &InputDescriptors::ReceivedHTLC => {
+                               writer.write_all(&[3; 1])?;
+                       }
+                       &InputDescriptors::RevokedOutput => {
+                               writer.write_all(&[4; 1])?;
+                       }
+               }
+               Ok(())
+       }
+}
+
+impl Readable for InputDescriptors {
+       fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
+               let input_descriptor = match <u8 as Readable>::read(reader)? {
+                       0 => {
+                               InputDescriptors::RevokedOfferedHTLC
+                       },
+                       1 => {
+                               InputDescriptors::RevokedReceivedHTLC
+                       },
+                       2 => {
+                               InputDescriptors::OfferedHTLC
+                       },
+                       3 => {
+                               InputDescriptors::ReceivedHTLC
+                       },
+                       4 => {
+                               InputDescriptors::RevokedOutput
+                       }
+                       _ => return Err(DecodeError::InvalidValue),
+               };
+               Ok(input_descriptor)
+       }
+}
+
+pub(crate) fn get_witnesses_weight(inputs: &[InputDescriptors]) -> usize {
+       let mut tx_weight = 2; // count segwit flags
+       for inp in inputs {
+               // We use expected weight (and not actual) as signatures and time lock delays may vary
+               tx_weight +=  match inp {
+                       // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
+                       &InputDescriptors::RevokedOfferedHTLC => {
+                               1 + 1 + 73 + 1 + 33 + 1 + 133
+                       },
+                       // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
+                       &InputDescriptors::RevokedReceivedHTLC => {
+                               1 + 1 + 73 + 1 + 33 + 1 + 139
+                       },
+                       // number_of_witness_elements + sig_length + counterpartyhtlc_sig  + preimage_length + preimage + witness_script_length + witness_script
+                       &InputDescriptors::OfferedHTLC => {
+                               1 + 1 + 73 + 1 + 32 + 1 + 133
+                       },
+                       // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
+                       &InputDescriptors::ReceivedHTLC => {
+                               1 + 1 + 73 + 1 + 1 + 1 + 139
+                       },
+                       // number_of_witness_elements + sig_length + revocation_sig + true_length + op_true + witness_script_length + witness_script
+                       &InputDescriptors::RevokedOutput => {
+                               1 + 1 + 73 + 1 + 1 + 1 + 77
+                       },
+               };
+       }
+       tx_weight
+}