Merge pull request #191 from nervosnetwork/yukang-more-on-payment-ses…

…sion

Payment session and error handling on onion packet forwarding

Cargo.toml

@@ -47,6 +47,7 @@ socket2 = "0.5.7"
 lnd-grpc-tonic-client = "0.3.0"
 git-version = "0.3.9"
 fiber-sphinx = "1.0.1"
+strum = { version = "0.26", features = ["derive"] }
 tokio = { version = "1", features = [
     "io-util",
     "macros",

src/errors.rs

@@ -36,6 +36,8 @@ pub enum Error {
     CkbInvoiceError(#[from] InvoiceError),
     #[error("Funding error: {0}")]
     FundingError(#[from] FundingError),
+    #[error("Send payment error: {0}")]
+    SendPaymentError(String),
     #[error("InvalidParameter: {0}")]
     InvalidParameter(String),
     #[error("Network Graph error: {0}")]

src/fiber/fee.rs

@@ -120,3 +120,14 @@ pub(crate) fn calculate_shutdown_tx_fee(
     let tx_size = shutdown_tx_size(udt_type_script, shutdown_scripts) as u64;
     fee_rate.fee(tx_size).as_u64()
 }
+
+pub(crate) fn calculate_tlc_forward_fee(amount: u128, fee_proportational_millionths: u128) -> u128 {
+    let fee = fee_proportational_millionths * amount;
+    let base_fee = fee / 1_000_000;
+    let remainder = fee % 1_000_000;
+    if remainder > 0 {
+        base_fee + 1
+    } else {
+        base_fee
+    }
+}