pub const MAX_SCID_VOUT_INDEX: u64 = 0xffff;
/// A `short_channel_id` construction error
-#[derive(Debug, PartialEq)]
+#[derive(Debug, PartialEq, Eq)]
pub enum ShortChannelIdError {
BlockOverflow,
TxIndexOverflow,
}
/// LDK has multiple reasons to generate fake short channel ids:
-/// 1) zero-conf channels that don't have a confirmed channel id yet
+/// 1) outbound SCID aliases we use for private channels
/// 2) phantom node payments, to get an scid for the phantom node's phantom channel
+/// 3) payments intended to be intercepted will route using a fake scid (this is typically used so
+/// the forwarding node can open a JIT channel to the next hop)
pub(crate) mod fake_scid {
use bitcoin::hash_types::BlockHash;
use bitcoin::hashes::hex::FromHex;
- use chain::keysinterface::{Sign, KeysInterface};
- use util::chacha20::ChaCha20;
- use util::scid_utils;
+ use crate::chain::keysinterface::EntropySource;
+ use crate::util::chacha20::ChaCha20;
+ use crate::util::scid_utils;
use core::convert::TryInto;
use core::ops::Deref;
- const TEST_SEGWIT_ACTIVATION_HEIGHT: u32 = 0;
+ const TEST_SEGWIT_ACTIVATION_HEIGHT: u32 = 1;
const MAINNET_SEGWIT_ACTIVATION_HEIGHT: u32 = 481_824;
const MAX_TX_INDEX: u32 = 2_500;
const MAX_NAMESPACES: u8 = 8; // We allocate 3 bits for the namespace identifier.
const NAMESPACE_ID_BITMASK: u8 = 0b111;
+ const BLOCKS_PER_MONTH: u32 = 144 /* blocks per day */ * 30 /* days per month */;
+ pub(crate) const MAX_SCID_BLOCKS_FROM_NOW: u32 = BLOCKS_PER_MONTH;
+
+
/// Fake scids are divided into namespaces, with each namespace having its own identifier between
/// [0..7]. This allows us to identify what namespace a fake scid corresponds to upon HTLC
/// receipt, and handle the HTLC accordingly. The namespace identifier is encrypted when encoded
/// into the fake scid.
#[derive(Copy, Clone)]
- pub(super) enum Namespace {
+ pub(crate) enum Namespace {
Phantom,
- // Coming soon: a variant for the zero-conf scid namespace
+ OutboundAlias,
+ Intercept
}
impl Namespace {
/// between segwit activation and the current best known height, and the tx index and output
/// index are also selected from a "reasonable" range. We add this logic because it makes it
/// non-obvious at a glance that the scid is fake, e.g. if it appears in invoice route hints.
- pub(super) fn get_fake_scid<Signer: Sign, K: Deref>(&self, highest_seen_blockheight: u32, genesis_hash: &BlockHash, fake_scid_rand_bytes: &[u8; 32], keys_manager: &K) -> u64
- where K::Target: KeysInterface<Signer = Signer>,
+ pub(crate) fn get_fake_scid<ES: Deref>(&self, highest_seen_blockheight: u32, genesis_hash: &BlockHash, fake_scid_rand_bytes: &[u8; 32], entropy_source: &ES) -> u64
+ where ES::Target: EntropySource,
{
// Ensure we haven't created a namespace that doesn't fit into the 3 bits we've allocated for
// namespaces.
assert!((*self as u8) < MAX_NAMESPACES);
- const BLOCKS_PER_MONTH: u32 = 144 /* blocks per day */ * 30 /* days per month */;
- let rand_bytes = keys_manager.get_secure_random_bytes();
+ let rand_bytes = entropy_source.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(MAX_SCID_BLOCKS_FROM_NOW);
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;
}
}
- pub fn get_phantom_scid<Signer: Sign, K: Deref>(fake_scid_rand_bytes: &[u8; 32], highest_seen_blockheight: u32, genesis_hash: &BlockHash, keys_manager: &K) -> u64
- where K::Target: KeysInterface<Signer = Signer>,
- {
- let namespace = Namespace::Phantom;
- namespace.get_fake_scid(highest_seen_blockheight, genesis_hash, fake_scid_rand_bytes, keys_manager)
- }
-
fn segwit_activation_height(genesis: &BlockHash) -> u32 {
const MAINNET_GENESIS_STR: &'static str = "000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f";
if BlockHash::from_hex(MAINNET_GENESIS_STR).unwrap() == *genesis {
}
}
- /// Returns whether the given fake scid falls into the given namespace.
- pub fn is_valid_phantom(fake_scid_rand_bytes: &[u8; 32], scid: u64) -> bool {
+ /// Returns whether the given fake scid falls into the phantom namespace.
+ pub fn is_valid_phantom(fake_scid_rand_bytes: &[u8; 32], scid: u64, genesis_hash: &BlockHash) -> bool {
let block_height = scid_utils::block_from_scid(&scid);
let tx_index = scid_utils::tx_index_from_scid(&scid);
let namespace = Namespace::Phantom;
let valid_vout = namespace.get_encrypted_vout(block_height, tx_index, fake_scid_rand_bytes);
- valid_vout == scid_utils::vout_from_scid(&scid) as u8
+ block_height >= segwit_activation_height(genesis_hash)
+ && valid_vout == scid_utils::vout_from_scid(&scid) as u8
+ }
+
+ /// Returns whether the given fake scid falls into the intercept namespace.
+ pub fn is_valid_intercept(fake_scid_rand_bytes: &[u8; 32], scid: u64, genesis_hash: &BlockHash) -> bool {
+ let block_height = scid_utils::block_from_scid(&scid);
+ let tx_index = scid_utils::tx_index_from_scid(&scid);
+ let namespace = Namespace::Intercept;
+ let valid_vout = namespace.get_encrypted_vout(block_height, tx_index, fake_scid_rand_bytes);
+ block_height >= segwit_activation_height(genesis_hash)
+ && valid_vout == scid_utils::vout_from_scid(&scid) as u8
}
#[cfg(test)]
mod tests {
use bitcoin::blockdata::constants::genesis_block;
use bitcoin::network::constants::Network;
- use util::scid_utils::fake_scid::{is_valid_phantom, MAINNET_SEGWIT_ACTIVATION_HEIGHT, MAX_TX_INDEX, MAX_NAMESPACES, Namespace, NAMESPACE_ID_BITMASK, segwit_activation_height, TEST_SEGWIT_ACTIVATION_HEIGHT};
- use util::scid_utils;
- use util::test_utils;
- use sync::Arc;
+ use crate::util::scid_utils::fake_scid::{is_valid_intercept, is_valid_phantom, MAINNET_SEGWIT_ACTIVATION_HEIGHT, MAX_TX_INDEX, MAX_NAMESPACES, Namespace, NAMESPACE_ID_BITMASK, segwit_activation_height, TEST_SEGWIT_ACTIVATION_HEIGHT};
+ use crate::util::scid_utils;
+ use crate::util::test_utils;
+ use crate::sync::Arc;
#[test]
fn namespace_identifier_is_within_range() {
let phantom_namespace = Namespace::Phantom;
assert!((phantom_namespace as u8) < MAX_NAMESPACES);
assert!((phantom_namespace as u8) <= NAMESPACE_ID_BITMASK);
+
+ let intercept_namespace = Namespace::Intercept;
+ assert!((intercept_namespace as u8) < MAX_NAMESPACES);
+ assert!((intercept_namespace as u8) <= NAMESPACE_ID_BITMASK);
}
#[test]
fn test_is_valid_phantom() {
let namespace = Namespace::Phantom;
let fake_scid_rand_bytes = [0; 32];
+ let testnet_genesis = genesis_block(Network::Testnet).header.block_hash();
+ let valid_encrypted_vout = namespace.get_encrypted_vout(0, 0, &fake_scid_rand_bytes);
+ let valid_fake_scid = scid_utils::scid_from_parts(1, 0, valid_encrypted_vout as u64).unwrap();
+ assert!(is_valid_phantom(&fake_scid_rand_bytes, valid_fake_scid, &testnet_genesis));
+ let invalid_fake_scid = scid_utils::scid_from_parts(1, 0, 12).unwrap();
+ assert!(!is_valid_phantom(&fake_scid_rand_bytes, invalid_fake_scid, &testnet_genesis));
+ }
+
+ #[test]
+ fn test_is_valid_intercept() {
+ let namespace = Namespace::Intercept;
+ let fake_scid_rand_bytes = [0; 32];
+ let testnet_genesis = genesis_block(Network::Testnet).header.block_hash();
let valid_encrypted_vout = namespace.get_encrypted_vout(0, 0, &fake_scid_rand_bytes);
- let valid_fake_scid = scid_utils::scid_from_parts(0, 0, valid_encrypted_vout as u64).unwrap();
- assert!(is_valid_phantom(&fake_scid_rand_bytes, valid_fake_scid));
- let invalid_fake_scid = scid_utils::scid_from_parts(0, 0, 12).unwrap();
- assert!(!is_valid_phantom(&fake_scid_rand_bytes, invalid_fake_scid));
+ let valid_fake_scid = scid_utils::scid_from_parts(1, 0, valid_encrypted_vout as u64).unwrap();
+ assert!(is_valid_intercept(&fake_scid_rand_bytes, valid_fake_scid, &testnet_genesis));
+ let invalid_fake_scid = scid_utils::scid_from_parts(1, 0, 12).unwrap();
+ assert!(!is_valid_intercept(&fake_scid_rand_bytes, invalid_fake_scid, &testnet_genesis));
}
#[test]
projects / rust-lightning / blobdiff