From 8012c2b213127372bdad150cdc354920d971087d Mon Sep 17 00:00:00 2001 From: Jeffrey Czyz Date: Tue, 28 May 2024 18:43:45 -0500 Subject: [PATCH] Use compact blinded paths for short-lived offers When an offer is short-lived, the likelihood of a channel used in a compact blinded path going away is low. Require passing the absolute expiry of an offer to ChannelManager::create_offer_builder so that it can be used to determine whether or not compact blinded path should be used. Use the same criteria for creating blinded paths for refunds as well. --- lightning/src/ln/channelmanager.rs | 83 ++++++++++++--- lightning/src/ln/offers_tests.rs | 158 ++++++++++++++++++++++++----- 2 files changed, 203 insertions(+), 38 deletions(-) diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs index 391f5b330..2fd170ebf 100644 --- a/lightning/src/ln/channelmanager.rs +++ b/lightning/src/ln/channelmanager.rs @@ -1554,8 +1554,9 @@ where /// # /// # fn example(channel_manager: T) -> Result<(), Bolt12SemanticError> { /// # let channel_manager = channel_manager.get_cm(); +/// # let absolute_expiry = None; /// let offer = channel_manager -/// .create_offer_builder()? +/// .create_offer_builder(absolute_expiry)? /// # ; /// # // Needed for compiling for c_bindings /// # let builder: lightning::offers::offer::OfferBuilder<_, _> = offer.into(); @@ -2287,6 +2288,19 @@ const MAX_UNFUNDED_CHANNEL_PEERS: usize = 50; /// many peers we reject new (inbound) connections. const MAX_NO_CHANNEL_PEERS: usize = 250; +/// The maximum expiration from the current time where an [`Offer`] or [`Refund`] is considered +/// short-lived, while anything with a greater expiration is considered long-lived. +/// +/// Using [`ChannelManager::create_offer_builder`] or [`ChannelManager::create_refund_builder`], +/// will included a [`BlindedPath`] created using: +/// - [`MessageRouter::create_compact_blinded_paths`] when short-lived, and +/// - [`MessageRouter::create_blinded_paths`] when long-lived. +/// +/// Using compact [`BlindedPath`]s may provide better privacy as the [`MessageRouter`] could select +/// more hops. However, since they use short channel ids instead of pubkeys, they are more likely to +/// become invalid over time as channels are closed. Thus, they are only suitable for short-term use. +pub const MAX_SHORT_LIVED_RELATIVE_EXPIRY: Duration = Duration::from_secs(60 * 60 * 24); + /// Used by [`ChannelManager::list_recent_payments`] to express the status of recent payments. /// These include payments that have yet to find a successful path, or have unresolved HTLCs. #[derive(Debug, PartialEq)] @@ -8240,16 +8254,17 @@ where macro_rules! create_offer_builder { ($self: ident, $builder: ty) => { /// Creates an [`OfferBuilder`] such that the [`Offer`] it builds is recognized by the - /// [`ChannelManager`] when handling [`InvoiceRequest`] messages for the offer. The offer will - /// not have an expiration unless otherwise set on the builder. + /// [`ChannelManager`] when handling [`InvoiceRequest`] messages for the offer. The offer's + /// expiration will be `absolute_expiry` if `Some`, otherwise it will not expire. /// /// # Privacy /// - /// Uses [`MessageRouter::create_compact_blinded_paths`] to construct a [`BlindedPath`] for the - /// offer. However, if one is not found, uses a one-hop [`BlindedPath`] with + /// Uses [`MessageRouter`] to construct a [`BlindedPath`] for the offer based on the given + /// `absolute_expiry` according to [`MAX_SHORT_LIVED_RELATIVE_EXPIRY`]. See those docs for + /// privacy implications. However, if one is not found, uses a one-hop [`BlindedPath`] with /// [`ChannelManager::get_our_node_id`] as the introduction node instead. In the latter case, - /// the node must be announced, otherwise, there is no way to find a path to the introduction in - /// order to send the [`InvoiceRequest`]. + /// the node must be announced, otherwise, there is no way to find a path to the introduction + /// node in order to send the [`InvoiceRequest`]. /// /// Also, uses a derived signing pubkey in the offer for recipient privacy. /// @@ -8264,13 +8279,15 @@ macro_rules! create_offer_builder { ($self: ident, $builder: ty) => { /// /// [`Offer`]: crate::offers::offer::Offer /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest - pub fn create_offer_builder(&$self) -> Result<$builder, Bolt12SemanticError> { + pub fn create_offer_builder( + &$self, absolute_expiry: Option + ) -> Result<$builder, Bolt12SemanticError> { let node_id = $self.get_our_node_id(); let expanded_key = &$self.inbound_payment_key; let entropy = &*$self.entropy_source; let secp_ctx = &$self.secp_ctx; - let path = $self.create_compact_blinded_path() + let path = $self.create_blinded_path_using_absolute_expiry(absolute_expiry) .map_err(|_| Bolt12SemanticError::MissingPaths)?; let builder = OfferBuilder::deriving_signing_pubkey( node_id, expanded_key, entropy, secp_ctx @@ -8278,6 +8295,11 @@ macro_rules! create_offer_builder { ($self: ident, $builder: ty) => { .chain_hash($self.chain_hash) .path(path); + let builder = match absolute_expiry { + None => builder, + Some(absolute_expiry) => builder.absolute_expiry(absolute_expiry), + }; + Ok(builder.into()) } } } @@ -8305,11 +8327,12 @@ macro_rules! create_refund_builder { ($self: ident, $builder: ty) => { /// /// # Privacy /// - /// Uses [`MessageRouter::create_compact_blinded_paths`] to construct a [`BlindedPath`] for the - /// refund. However, if one is not found, uses a one-hop [`BlindedPath`] with + /// Uses [`MessageRouter`] to construct a [`BlindedPath`] for the refund based on the given + /// `absolute_expiry` according to [`MAX_SHORT_LIVED_RELATIVE_EXPIRY`]. See those docs for + /// privacy implications. However, if one is not found, uses a one-hop [`BlindedPath`] with /// [`ChannelManager::get_our_node_id`] as the introduction node instead. In the latter case, - /// the node must be announced, otherwise, there is no way to find a path to the introduction in - /// order to send the [`Bolt12Invoice`]. + /// the node must be announced, otherwise, there is no way to find a path to the introduction + /// node in order to send the [`Bolt12Invoice`]. /// /// Also, uses a derived payer id in the refund for payer privacy. /// @@ -8338,7 +8361,7 @@ macro_rules! create_refund_builder { ($self: ident, $builder: ty) => { let entropy = &*$self.entropy_source; let secp_ctx = &$self.secp_ctx; - let path = $self.create_compact_blinded_path() + let path = $self.create_blinded_path_using_absolute_expiry(Some(absolute_expiry)) .map_err(|_| Bolt12SemanticError::MissingPaths)?; let builder = RefundBuilder::deriving_payer_id( node_id, expanded_key, entropy, secp_ctx, amount_msats, payment_id @@ -8688,6 +8711,38 @@ where inbound_payment::get_payment_preimage(payment_hash, payment_secret, &self.inbound_payment_key) } + /// Creates a blinded path by delegating to [`MessageRouter`] based on the path's intended + /// lifetime. + /// + /// Whether or not the path is compact depends on whether the path is short-lived or long-lived, + /// respectively, based on the given `absolute_expiry` as seconds since the Unix epoch. See + /// [`MAX_SHORT_LIVED_RELATIVE_EXPIRY`]. + fn create_blinded_path_using_absolute_expiry( + &self, absolute_expiry: Option + ) -> Result { + let now = self.duration_since_epoch(); + let max_short_lived_absolute_expiry = now.saturating_add(MAX_SHORT_LIVED_RELATIVE_EXPIRY); + + if absolute_expiry.unwrap_or(Duration::MAX) <= max_short_lived_absolute_expiry { + self.create_compact_blinded_path() + } else { + self.create_blinded_path() + } + } + + pub(super) fn duration_since_epoch(&self) -> Duration { + #[cfg(not(feature = "std"))] + let now = Duration::from_secs( + self.highest_seen_timestamp.load(Ordering::Acquire) as u64 + ); + #[cfg(feature = "std")] + let now = std::time::SystemTime::now() + .duration_since(std::time::SystemTime::UNIX_EPOCH) + .expect("SystemTime::now() should come after SystemTime::UNIX_EPOCH"); + + now + } + /// Creates a blinded path by delegating to [`MessageRouter::create_blinded_paths`]. /// /// Errors if the `MessageRouter` errors or returns an empty `Vec`. diff --git a/lightning/src/ln/offers_tests.rs b/lightning/src/ln/offers_tests.rs index 5594c8ba9..725b8dfe5 100644 --- a/lightning/src/ln/offers_tests.rs +++ b/lightning/src/ln/offers_tests.rs @@ -46,7 +46,7 @@ use core::time::Duration; use crate::blinded_path::{BlindedPath, IntroductionNode}; use crate::blinded_path::payment::{Bolt12OfferContext, Bolt12RefundContext, PaymentContext}; use crate::events::{Event, MessageSendEventsProvider, PaymentPurpose}; -use crate::ln::channelmanager::{PaymentId, RecentPaymentDetails, Retry, self}; +use crate::ln::channelmanager::{MAX_SHORT_LIVED_RELATIVE_EXPIRY, PaymentId, RecentPaymentDetails, Retry, self}; use crate::ln::functional_test_utils::*; use crate::ln::msgs::{ChannelMessageHandler, Init, NodeAnnouncement, OnionMessage, OnionMessageHandler, RoutingMessageHandler, SocketAddress, UnsignedGossipMessage, UnsignedNodeAnnouncement}; use crate::offers::invoice::Bolt12Invoice; @@ -274,7 +274,7 @@ fn prefers_non_tor_nodes_in_blinded_paths() { announce_node_address(charlie, &[alice, bob, david, &nodes[4], &nodes[5]], tor.clone()); let offer = bob.node - .create_offer_builder().unwrap() + .create_offer_builder(None).unwrap() .amount_msats(10_000_000) .build().unwrap(); assert_ne!(offer.signing_pubkey(), Some(bob_id)); @@ -290,7 +290,7 @@ fn prefers_non_tor_nodes_in_blinded_paths() { announce_node_address(&nodes[5], &[alice, bob, charlie, david, &nodes[4]], tor.clone()); let offer = bob.node - .create_offer_builder().unwrap() + .create_offer_builder(None).unwrap() .amount_msats(10_000_000) .build().unwrap(); assert_ne!(offer.signing_pubkey(), Some(bob_id)); @@ -341,7 +341,7 @@ fn prefers_more_connected_nodes_in_blinded_paths() { disconnect_peers(david, &[bob, &nodes[4], &nodes[5]]); let offer = bob.node - .create_offer_builder().unwrap() + .create_offer_builder(None).unwrap() .amount_msats(10_000_000) .build().unwrap(); assert_ne!(offer.signing_pubkey(), Some(bob_id)); @@ -352,6 +352,124 @@ fn prefers_more_connected_nodes_in_blinded_paths() { } } +/// Checks that blinded paths are compact for short-lived offers. +#[test] +fn creates_short_lived_offer() { + let chanmon_cfgs = create_chanmon_cfgs(2); + let node_cfgs = create_node_cfgs(2, &chanmon_cfgs); + let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]); + let nodes = create_network(2, &node_cfgs, &node_chanmgrs); + + create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000_000, 1_000_000_000); + + let alice = &nodes[0]; + let alice_id = alice.node.get_our_node_id(); + let bob = &nodes[1]; + + let absolute_expiry = alice.node.duration_since_epoch() + MAX_SHORT_LIVED_RELATIVE_EXPIRY; + let offer = alice.node + .create_offer_builder(Some(absolute_expiry)).unwrap() + .build().unwrap(); + assert_eq!(offer.absolute_expiry(), Some(absolute_expiry)); + assert!(!offer.paths().is_empty()); + for path in offer.paths() { + let introduction_node_id = resolve_introduction_node(bob, &path); + assert_eq!(introduction_node_id, alice_id); + assert!(matches!(path.introduction_node, IntroductionNode::DirectedShortChannelId(..))); + } +} + +/// Checks that blinded paths are not compact for long-lived offers. +#[test] +fn creates_long_lived_offer() { + let chanmon_cfgs = create_chanmon_cfgs(2); + let node_cfgs = create_node_cfgs(2, &chanmon_cfgs); + let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]); + let nodes = create_network(2, &node_cfgs, &node_chanmgrs); + + create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000_000, 1_000_000_000); + + let alice = &nodes[0]; + let alice_id = alice.node.get_our_node_id(); + + let absolute_expiry = alice.node.duration_since_epoch() + MAX_SHORT_LIVED_RELATIVE_EXPIRY + + Duration::from_secs(1); + let offer = alice.node + .create_offer_builder(Some(absolute_expiry)) + .unwrap() + .build().unwrap(); + assert_eq!(offer.absolute_expiry(), Some(absolute_expiry)); + assert!(!offer.paths().is_empty()); + for path in offer.paths() { + assert_eq!(path.introduction_node, IntroductionNode::NodeId(alice_id)); + } + + let offer = alice.node + .create_offer_builder(None).unwrap() + .build().unwrap(); + assert_eq!(offer.absolute_expiry(), None); + assert!(!offer.paths().is_empty()); + for path in offer.paths() { + assert_eq!(path.introduction_node, IntroductionNode::NodeId(alice_id)); + } +} + +/// Checks that blinded paths are compact for short-lived refunds. +#[test] +fn creates_short_lived_refund() { + let chanmon_cfgs = create_chanmon_cfgs(2); + let node_cfgs = create_node_cfgs(2, &chanmon_cfgs); + let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]); + let nodes = create_network(2, &node_cfgs, &node_chanmgrs); + + create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000_000, 1_000_000_000); + + let alice = &nodes[0]; + let bob = &nodes[1]; + let bob_id = bob.node.get_our_node_id(); + + let absolute_expiry = bob.node.duration_since_epoch() + MAX_SHORT_LIVED_RELATIVE_EXPIRY; + let payment_id = PaymentId([1; 32]); + let refund = bob.node + .create_refund_builder(10_000_000, absolute_expiry, payment_id, Retry::Attempts(0), None) + .unwrap() + .build().unwrap(); + assert_eq!(refund.absolute_expiry(), Some(absolute_expiry)); + assert!(!refund.paths().is_empty()); + for path in refund.paths() { + let introduction_node_id = resolve_introduction_node(alice, &path); + assert_eq!(introduction_node_id, bob_id); + assert!(matches!(path.introduction_node, IntroductionNode::DirectedShortChannelId(..))); + } +} + +/// Checks that blinded paths are not compact for long-lived refunds. +#[test] +fn creates_long_lived_refund() { + let chanmon_cfgs = create_chanmon_cfgs(2); + let node_cfgs = create_node_cfgs(2, &chanmon_cfgs); + let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]); + let nodes = create_network(2, &node_cfgs, &node_chanmgrs); + + create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000_000, 1_000_000_000); + + let bob = &nodes[1]; + let bob_id = bob.node.get_our_node_id(); + + let absolute_expiry = bob.node.duration_since_epoch() + MAX_SHORT_LIVED_RELATIVE_EXPIRY + + Duration::from_secs(1); + let payment_id = PaymentId([1; 32]); + let refund = bob.node + .create_refund_builder(10_000_000, absolute_expiry, payment_id, Retry::Attempts(0), None) + .unwrap() + .build().unwrap(); + assert_eq!(refund.absolute_expiry(), Some(absolute_expiry)); + assert!(!refund.paths().is_empty()); + for path in refund.paths() { + assert_eq!(path.introduction_node, IntroductionNode::NodeId(bob_id)); + } +} + /// Checks that an offer can be paid through blinded paths and that ephemeral pubkeys are used /// rather than exposing a node's pubkey. #[test] @@ -391,16 +509,14 @@ fn creates_and_pays_for_offer_using_two_hop_blinded_path() { disconnect_peers(david, &[bob, &nodes[4], &nodes[5]]); let offer = alice.node - .create_offer_builder() + .create_offer_builder(None) .unwrap() .amount_msats(10_000_000) .build().unwrap(); assert_ne!(offer.signing_pubkey(), Some(alice_id)); assert!(!offer.paths().is_empty()); for path in offer.paths() { - let introduction_node_id = resolve_introduction_node(david, &path); - assert_eq!(introduction_node_id, bob_id); - assert!(matches!(path.introduction_node, IntroductionNode::DirectedShortChannelId(..))); + assert_eq!(path.introduction_node, IntroductionNode::NodeId(bob_id)); } let payment_id = PaymentId([1; 32]); @@ -501,9 +617,7 @@ fn creates_and_pays_for_refund_using_two_hop_blinded_path() { assert_ne!(refund.payer_id(), david_id); assert!(!refund.paths().is_empty()); for path in refund.paths() { - let introduction_node_id = resolve_introduction_node(alice, &path); - assert_eq!(introduction_node_id, charlie_id); - assert!(matches!(path.introduction_node, IntroductionNode::DirectedShortChannelId(..))); + assert_eq!(path.introduction_node, IntroductionNode::NodeId(charlie_id)); } expect_recent_payment!(david, RecentPaymentDetails::AwaitingInvoice, payment_id); @@ -553,15 +667,13 @@ fn creates_and_pays_for_offer_using_one_hop_blinded_path() { let bob_id = bob.node.get_our_node_id(); let offer = alice.node - .create_offer_builder().unwrap() + .create_offer_builder(None).unwrap() .amount_msats(10_000_000) .build().unwrap(); assert_ne!(offer.signing_pubkey(), Some(alice_id)); assert!(!offer.paths().is_empty()); for path in offer.paths() { - let introduction_node_id = resolve_introduction_node(bob, &path); - assert_eq!(introduction_node_id, alice_id); - assert!(matches!(path.introduction_node, IntroductionNode::DirectedShortChannelId(..))); + assert_eq!(path.introduction_node, IntroductionNode::NodeId(alice_id)); } let payment_id = PaymentId([1; 32]); @@ -630,9 +742,7 @@ fn creates_and_pays_for_refund_using_one_hop_blinded_path() { assert_ne!(refund.payer_id(), bob_id); assert!(!refund.paths().is_empty()); for path in refund.paths() { - let introduction_node_id = resolve_introduction_node(alice, &path); - assert_eq!(introduction_node_id, bob_id); - assert!(matches!(path.introduction_node, IntroductionNode::DirectedShortChannelId(..))); + assert_eq!(path.introduction_node, IntroductionNode::NodeId(bob_id)); } expect_recent_payment!(bob, RecentPaymentDetails::AwaitingInvoice, payment_id); @@ -677,7 +787,7 @@ fn pays_for_offer_without_blinded_paths() { let bob_id = bob.node.get_our_node_id(); let offer = alice.node - .create_offer_builder().unwrap() + .create_offer_builder(None).unwrap() .clear_paths() .amount_msats(10_000_000) .build().unwrap(); @@ -765,7 +875,7 @@ fn fails_creating_offer_without_blinded_paths() { create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000_000, 1_000_000_000); - match nodes[0].node.create_offer_builder() { + match nodes[0].node.create_offer_builder(None) { Ok(_) => panic!("Expected error"), Err(e) => assert_eq!(e, Bolt12SemanticError::MissingPaths), } @@ -808,7 +918,7 @@ fn fails_creating_invoice_request_for_unsupported_chain() { let bob = &nodes[1]; let offer = alice.node - .create_offer_builder().unwrap() + .create_offer_builder(None).unwrap() .clear_chains() .chain(Network::Signet) .build().unwrap(); @@ -868,7 +978,7 @@ fn fails_creating_invoice_request_without_blinded_reply_path() { disconnect_peers(david, &[bob, &nodes[4], &nodes[5]]); let offer = alice.node - .create_offer_builder().unwrap() + .create_offer_builder(None).unwrap() .amount_msats(10_000_000) .build().unwrap(); @@ -902,7 +1012,7 @@ fn fails_creating_invoice_request_with_duplicate_payment_id() { disconnect_peers(alice, &[charlie, david, &nodes[4], &nodes[5]]); let offer = alice.node - .create_offer_builder().unwrap() + .create_offer_builder(None).unwrap() .amount_msats(10_000_000) .build().unwrap(); @@ -988,7 +1098,7 @@ fn fails_sending_invoice_without_blinded_payment_paths_for_offer() { disconnect_peers(david, &[bob, &nodes[4], &nodes[5]]); let offer = alice.node - .create_offer_builder().unwrap() + .create_offer_builder(None).unwrap() .amount_msats(10_000_000) .build().unwrap(); -- 2.39.5