use bitcoin::secp256k1::{self, PublicKey, Secp256k1, SecretKey};
-use crate::sign::EntropySource;
use crate::ln::msgs::DecodeError;
+use crate::offers::invoice::BlindedPayInfo;
+use crate::sign::EntropySource;
use crate::util::ser::{Readable, Writeable, Writer};
use crate::io;
/// Create a blinded path for a payment, to be forwarded along `intermediate_nodes`.
///
- /// Errors if a provided node id is invalid.
+ /// Errors if:
+ /// * a provided node id is invalid
+ /// * [`BlindedPayInfo`] calculation results in an integer overflow
+ /// * any unknown features are required in the provided [`ForwardTlvs`]
+ ///
+ /// [`ForwardTlvs`]: crate::blinded_path::payment::ForwardTlvs
// TODO: make all payloads the same size with padding + add dummy hops
pub fn new_for_payment<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>(
intermediate_nodes: &[(PublicKey, payment::ForwardTlvs)], payee_node_id: PublicKey,
payee_tlvs: payment::ReceiveTlvs, entropy_source: &ES, secp_ctx: &Secp256k1<T>
- ) -> Result<Self, ()> {
+ ) -> Result<(BlindedPayInfo, Self), ()> {
let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
- Ok(BlindedPath {
+ let blinded_payinfo = payment::compute_payinfo(intermediate_nodes, &payee_tlvs)?;
+ Ok((blinded_payinfo, BlindedPath {
introduction_node_id: intermediate_nodes.first().map_or(payee_node_id, |n| n.0),
blinding_point: PublicKey::from_secret_key(secp_ctx, &blinding_secret),
blinded_hops: payment::blinded_hops(
secp_ctx, intermediate_nodes, payee_node_id, payee_tlvs, &blinding_secret
).map_err(|_| ())?,
- })
+ }))
}
}
use crate::ln::PaymentSecret;
use crate::ln::features::BlindedHopFeatures;
use crate::ln::msgs::DecodeError;
+use crate::offers::invoice::BlindedPayInfo;
use crate::prelude::*;
use crate::util::ser::{Readable, Writeable, Writer};
+use core::convert::TryFrom;
+
/// Data to construct a [`BlindedHop`] for forwarding a payment.
pub struct ForwardTlvs {
/// The short channel id this payment should be forwarded out over.
utils::construct_blinded_hops(secp_ctx, pks, tlvs, session_priv)
}
+pub(super) fn compute_payinfo(
+ intermediate_nodes: &[(PublicKey, ForwardTlvs)], payee_tlvs: &ReceiveTlvs
+) -> Result<BlindedPayInfo, ()> {
+ let mut curr_base_fee: u64 = 0;
+ let mut curr_prop_mil: u64 = 0;
+ let mut cltv_expiry_delta: u16 = 0;
+ for (_, tlvs) in intermediate_nodes.iter().rev() {
+ // In the future, we'll want to take the intersection of all supported features for the
+ // `BlindedPayInfo`, but there are no features in that context right now.
+ if tlvs.features.requires_unknown_bits_from(&BlindedHopFeatures::empty()) { return Err(()) }
+
+ let next_base_fee = tlvs.payment_relay.fee_base_msat as u64;
+ let next_prop_mil = tlvs.payment_relay.fee_proportional_millionths as u64;
+ // Use integer arithmetic to compute `ceil(a/b)` as `(a+b-1)/b`
+ // ((curr_base_fee * (1_000_000 + next_prop_mil)) / 1_000_000) + next_base_fee
+ curr_base_fee = curr_base_fee.checked_mul(1_000_000 + next_prop_mil)
+ .and_then(|f| f.checked_add(1_000_000 - 1))
+ .map(|f| f / 1_000_000)
+ .and_then(|f| f.checked_add(next_base_fee))
+ .ok_or(())?;
+ // ceil(((curr_prop_mil + 1_000_000) * (next_prop_mil + 1_000_000)) / 1_000_000) - 1_000_000
+ curr_prop_mil = curr_prop_mil.checked_add(1_000_000)
+ .and_then(|f1| next_prop_mil.checked_add(1_000_000).and_then(|f2| f2.checked_mul(f1)))
+ .and_then(|f| f.checked_add(1_000_000 - 1))
+ .map(|f| f / 1_000_000)
+ .and_then(|f| f.checked_sub(1_000_000))
+ .ok_or(())?;
+
+ cltv_expiry_delta = cltv_expiry_delta.checked_add(tlvs.payment_relay.cltv_expiry_delta).ok_or(())?;
+ }
+ Ok(BlindedPayInfo {
+ fee_base_msat: u32::try_from(curr_base_fee).map_err(|_| ())?,
+ fee_proportional_millionths: u32::try_from(curr_prop_mil).map_err(|_| ())?,
+ cltv_expiry_delta,
+ htlc_minimum_msat: 1, // TODO
+ htlc_maximum_msat: 21_000_000 * 100_000_000 * 1_000, // TODO
+ features: BlindedHopFeatures::empty(),
+ })
+}
+
impl_writeable_msg!(PaymentRelay, {
cltv_expiry_delta,
fee_proportional_millionths,
max_cltv_expiry,
htlc_minimum_msat
}, {});
+
+#[cfg(test)]
+mod tests {
+ use bitcoin::secp256k1::PublicKey;
+ use crate::blinded_path::payment::{ForwardTlvs, ReceiveTlvs, PaymentConstraints, PaymentRelay};
+ use crate::ln::PaymentSecret;
+ use crate::ln::features::BlindedHopFeatures;
+
+ #[test]
+ fn compute_payinfo() {
+ // Taken from the spec example for aggregating blinded payment info. See
+ // https://github.com/lightning/bolts/blob/master/proposals/route-blinding.md#blinded-payments
+ let dummy_pk = PublicKey::from_slice(&[2; 33]).unwrap();
+ let intermediate_nodes = vec![(dummy_pk, ForwardTlvs {
+ short_channel_id: 0,
+ payment_relay: PaymentRelay {
+ cltv_expiry_delta: 144,
+ fee_proportional_millionths: 500,
+ fee_base_msat: 100,
+ },
+ payment_constraints: PaymentConstraints {
+ max_cltv_expiry: 0,
+ htlc_minimum_msat: 100,
+ },
+ features: BlindedHopFeatures::empty(),
+ }), (dummy_pk, ForwardTlvs {
+ short_channel_id: 0,
+ payment_relay: PaymentRelay {
+ cltv_expiry_delta: 144,
+ fee_proportional_millionths: 500,
+ fee_base_msat: 100,
+ },
+ payment_constraints: PaymentConstraints {
+ max_cltv_expiry: 0,
+ htlc_minimum_msat: 1_000,
+ },
+ features: BlindedHopFeatures::empty(),
+ })];
+ let recv_tlvs = ReceiveTlvs {
+ payment_secret: PaymentSecret([0; 32]),
+ payment_constraints: PaymentConstraints {
+ max_cltv_expiry: 0,
+ htlc_minimum_msat: 1,
+ },
+ };
+ let blinded_payinfo = super::compute_payinfo(&intermediate_nodes[..], &recv_tlvs).unwrap();
+ assert_eq!(blinded_payinfo.fee_base_msat, 201);
+ assert_eq!(blinded_payinfo.fee_proportional_millionths, 1001);
+ assert_eq!(blinded_payinfo.cltv_expiry_delta, 288);
+ }
+
+ #[test]
+ fn compute_payinfo_1_hop() {
+ let recv_tlvs = ReceiveTlvs {
+ payment_secret: PaymentSecret([0; 32]),
+ payment_constraints: PaymentConstraints {
+ max_cltv_expiry: 0,
+ htlc_minimum_msat: 1,
+ },
+ };
+ let blinded_payinfo = super::compute_payinfo(&[], &recv_tlvs).unwrap();
+ assert_eq!(blinded_payinfo.fee_base_msat, 0);
+ assert_eq!(blinded_payinfo.fee_proportional_millionths, 0);
+ assert_eq!(blinded_payinfo.cltv_expiry_delta, 0);
+ }
+}
projects / rust-lightning / commitdiff