Stop using an introduction node in blinded message paths#4647

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jkczyz merged 1 commit into from
Jun 8, 2026
Merged

Stop using an introduction node in blinded message paths #4647

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157 changes: 2 additions & 155 deletions lightning/src/ln/offers_tests.rs
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Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -56,7 +56,7 @@ use crate::ln::channelmanager::{PaymentId, RecentPaymentDetails, self};
use crate::ln::outbound_payment::{Bolt12PaymentError, RecipientOnionFields, Retry};
use crate::types::features::Bolt12InvoiceFeatures;
use crate::ln::functional_test_utils::*;
use crate::ln::msgs::{BaseMessageHandler, ChannelMessageHandler, Init, NodeAnnouncement, OnionMessage, OnionMessageHandler, RoutingMessageHandler, SocketAddress, UnsignedGossipMessage, UnsignedNodeAnnouncement};
use crate::ln::msgs::{BaseMessageHandler, ChannelMessageHandler, Init, OnionMessage, OnionMessageHandler};
use crate::ln::outbound_payment::IDEMPOTENCY_TIMEOUT_TICKS;
use crate::offers::invoice::Bolt12Invoice;
use crate::offers::invoice_error::InvoiceError;
Expand All@@ -66,9 +66,8 @@ use crate::offers::offer::OfferBuilder;
use crate::offers::parse::Bolt12SemanticError;
use crate::onion_message::messenger::{DefaultMessageRouter, Destination, MessageRouter, MessageSendInstructions, NodeIdMessageRouter, NullMessageRouter, PeeledOnion, DUMMY_HOPS_PATH_LENGTH, QR_CODED_DUMMY_HOPS_PATH_LENGTH};
use crate::onion_message::offers::OffersMessage;
use crate::routing::gossip::{NodeAlias, NodeId};
use crate::routing::router::{DEFAULT_PAYMENT_DUMMY_HOPS, PaymentParameters, RouteParameters, RouteParametersConfig};
use crate::sign::{NodeSigner, Recipient};
use crate::sign::NodeSigner;
use crate::util::ser::Writeable;

/// This used to determine whether we built a compact path or not, but now its just a random
Expand DownExpand Up@@ -125,38 +124,6 @@ fn disconnect_peers<'a, 'b, 'c>(node_a: &Node<'a, 'b, 'c>, peers: &[&Node<'a, 'b
}
}

fn announce_node_address<'a, 'b, 'c>(
node: &Node<'a, 'b, 'c>, peers: &[&Node<'a, 'b, 'c>], address: SocketAddress,
) {
let features = node.onion_messenger.provided_node_features()
| node.gossip_sync.provided_node_features();
let rgb = [0u8; 3];
let announcement = UnsignedNodeAnnouncement {
features,
timestamp: 1000,
node_id: NodeId::from_pubkey(&node.keys_manager.get_node_id(Recipient::Node).unwrap()),
rgb,
alias: NodeAlias([0u8; 32]),
addresses: vec![address],
excess_address_data: Vec::new(),
excess_data: Vec::new(),
};
let signature = node.keys_manager.sign_gossip_message(
UnsignedGossipMessage::NodeAnnouncement(&announcement)
).unwrap();

let msg = NodeAnnouncement {
signature,
contents: announcement
};

let node_pubkey = node.node.get_our_node_id();
node.gossip_sync.handle_node_announcement(None, &msg).unwrap();
for peer in peers {
peer.gossip_sync.handle_node_announcement(Some(node_pubkey), &msg).unwrap();
}
}

fn resolve_introduction_node<'a, 'b, 'c>(node: &Node<'a, 'b, 'c>, path: &BlindedMessagePath) -> PublicKey {
path.public_introduction_node_id(&node.network_graph.read_only())
.and_then(|node_id| node_id.as_pubkey().ok())
Expand DownExpand Up@@ -362,126 +329,6 @@ fn create_refund_with_no_blinded_path() {
assert!(refund.paths().is_empty());
}

/// Checks that blinded paths without Tor-only nodes are preferred when constructing an offer.
#[test]
fn prefers_non_tor_nodes_in_blinded_paths() {
let mut accept_forward_cfg = test_default_channel_config();
accept_forward_cfg.accept_forwards_to_priv_channels = true;

let mut features = channelmanager::provided_init_features(&accept_forward_cfg);
features.set_onion_messages_optional();
features.set_route_blinding_optional();

let chanmon_cfgs = create_chanmon_cfgs(6);
let node_cfgs = create_node_cfgs(6, &chanmon_cfgs);

*node_cfgs[1].override_init_features.borrow_mut() = Some(features);

let node_chanmgrs = create_node_chanmgrs(
6, &node_cfgs, &[None, Some(accept_forward_cfg), None, None, None, None]
);
let nodes = create_network(6, &node_cfgs, &node_chanmgrs);

create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000_000, 1_000_000_000);
create_unannounced_chan_between_nodes_with_value(&nodes, 2, 3, 10_000_000, 1_000_000_000);
create_announced_chan_between_nodes_with_value(&nodes, 1, 2, 10_000_000, 1_000_000_000);
create_announced_chan_between_nodes_with_value(&nodes, 1, 4, 10_000_000, 1_000_000_000);
create_announced_chan_between_nodes_with_value(&nodes, 1, 5, 10_000_000, 1_000_000_000);
create_announced_chan_between_nodes_with_value(&nodes, 2, 4, 10_000_000, 1_000_000_000);
create_announced_chan_between_nodes_with_value(&nodes, 2, 5, 10_000_000, 1_000_000_000);

// Add an extra channel so that more than one of Bob's peers have MIN_PEER_CHANNELS.
create_announced_chan_between_nodes_with_value(&nodes, 4, 5, 10_000_000, 1_000_000_000);

let (alice, bob, charlie, david) = (&nodes[0], &nodes[1], &nodes[2], &nodes[3]);
let bob_id = bob.node.get_our_node_id();
let charlie_id = charlie.node.get_our_node_id();

disconnect_peers(alice, &[charlie, david, &nodes[4], &nodes[5]]);
disconnect_peers(david, &[bob, &nodes[4], &nodes[5]]);

let tor = SocketAddress::OnionV2([255, 254, 253, 252, 251, 250, 249, 248, 247, 246, 38, 7]);
announce_node_address(charlie, &[alice, bob, david, &nodes[4], &nodes[5]], tor.clone());

let offer = bob.node
.create_offer_builder().unwrap()
.amount_msats(10_000_000)
.build().unwrap();
assert_ne!(offer.issuer_signing_pubkey(), Some(bob_id));
assert!(!offer.paths().is_empty());
for path in offer.paths() {
let introduction_node_id = resolve_introduction_node(david, &path);
assert_ne!(introduction_node_id, bob_id);
assert_ne!(introduction_node_id, charlie_id);
}

// Use a one-hop blinded path when Bob is announced and all his peers are Tor-only.
announce_node_address(&nodes[4], &[alice, bob, charlie, david, &nodes[5]], tor.clone());
announce_node_address(&nodes[5], &[alice, bob, charlie, david, &nodes[4]], tor.clone());

let offer = bob.node
.create_offer_builder().unwrap()
.amount_msats(10_000_000)
.build().unwrap();
assert_ne!(offer.issuer_signing_pubkey(), Some(bob_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);
}
}

/// Checks that blinded paths prefer an introduction node that is the most connected.
#[test]
fn prefers_more_connected_nodes_in_blinded_paths() {
let mut accept_forward_cfg = test_default_channel_config();
accept_forward_cfg.accept_forwards_to_priv_channels = true;

let mut features = channelmanager::provided_init_features(&accept_forward_cfg);
features.set_onion_messages_optional();
features.set_route_blinding_optional();

let chanmon_cfgs = create_chanmon_cfgs(6);
let node_cfgs = create_node_cfgs(6, &chanmon_cfgs);

*node_cfgs[1].override_init_features.borrow_mut() = Some(features);

let node_chanmgrs = create_node_chanmgrs(
6, &node_cfgs, &[None, Some(accept_forward_cfg), None, None, None, None]
);
let nodes = create_network(6, &node_cfgs, &node_chanmgrs);

create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000_000, 1_000_000_000);
create_unannounced_chan_between_nodes_with_value(&nodes, 2, 3, 10_000_000, 1_000_000_000);
create_announced_chan_between_nodes_with_value(&nodes, 1, 2, 10_000_000, 1_000_000_000);
create_announced_chan_between_nodes_with_value(&nodes, 1, 4, 10_000_000, 1_000_000_000);
create_announced_chan_between_nodes_with_value(&nodes, 1, 5, 10_000_000, 1_000_000_000);
create_announced_chan_between_nodes_with_value(&nodes, 2, 4, 10_000_000, 1_000_000_000);
create_announced_chan_between_nodes_with_value(&nodes, 2, 5, 10_000_000, 1_000_000_000);

// Add extra channels so that more than one of Bob's peers have MIN_PEER_CHANNELS and one has
// more than the others.
create_announced_chan_between_nodes_with_value(&nodes, 0, 4, 10_000_000, 1_000_000_000);
create_announced_chan_between_nodes_with_value(&nodes, 3, 4, 10_000_000, 1_000_000_000);

let (alice, bob, charlie, david) = (&nodes[0], &nodes[1], &nodes[2], &nodes[3]);
let bob_id = bob.node.get_our_node_id();

disconnect_peers(alice, &[charlie, david, &nodes[4], &nodes[5]]);
disconnect_peers(david, &[bob, &nodes[4], &nodes[5]]);

let offer = bob.node
.create_offer_builder().unwrap()
.amount_msats(10_000_000)
.build().unwrap();
assert_ne!(offer.issuer_signing_pubkey(), Some(bob_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, nodes[4].node.get_our_node_id());
}
}

/// Tests the dummy hop behavior of Offers based on the message router used:
/// - Compact paths (`DefaultMessageRouter`) should not include dummy hops.
/// - Node ID paths (`NodeIdMessageRouter`) may include 0 to [`MAX_DUMMY_HOPS_COUNT`] dummy hops.
Expand Down
69 changes: 33 additions & 36 deletions lightning/src/onion_message/messenger.rs
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -563,10 +563,6 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Logger, ES: EntropySource>
// Limit the number of blinded paths that are computed.
const MAX_PATHS: usize = 3;

// Ensure peers have at least three channels so that it is more difficult to infer the
// recipient's node_id.
const MIN_PEER_CHANNELS: usize = 3;

let network_graph = network_graph.deref().read_only();
let is_recipient_announced =
network_graph.nodes().contains_key(&NodeId::from_pubkey(&recipient));
Expand DownExpand Up@@ -596,32 +592,6 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Logger, ES: EntropySource>

let compact_paths = !never_compact_path && size_constrained;

let has_one_peer = peers.len() == 1;
let mut peer_info = peers
.map(|peer| MessageForwardNode {
short_channel_id: if compact_paths { peer.short_channel_id } else { None },
..peer
})
// Limit to peers with announced channels unless the recipient is unannounced.
.filter_map(|peer| {
network_graph
.node(&NodeId::from_pubkey(&peer.node_id))
.filter(|info| {
!is_recipient_announced || info.channels.len() >= MIN_PEER_CHANNELS
})
.map(|info| (peer, info.is_tor_only(), info.channels.len()))
// Allow messages directly with the only peer when unannounced.
.or_else(|| (!is_recipient_announced && has_one_peer).then(|| (peer, false, 0)))
})
// Exclude Tor-only nodes when the recipient is announced.
.filter(|(_, is_tor_only, _)| !(*is_tor_only && is_recipient_announced))
.collect::<Vec<_>>();

// Prefer using non-Tor nodes with the most channels as the introduction node.
peer_info.sort_unstable_by(|(_, a_tor_only, a_channels), (_, b_tor_only, b_channels)| {
a_tor_only.cmp(b_tor_only).then(a_channels.cmp(b_channels).reverse())
});

let build_path = |intermediate_hops: &[MessageForwardNode]| {
// Calculate the dummy hops given the total hop count target (including the recipient).
let dummy_hops_count = path_len_incl_dummys.saturating_sub(intermediate_hops.len() + 1);
Expand All@@ -638,12 +608,39 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Logger, ES: EntropySource>
)
};

// Try to create paths from peer info, fall back to direct path if needed
let mut paths = peer_info
.into_iter()
.map(|(peer, _, _)| build_path(&[peer]))
.take(MAX_PATHS)
.collect::<Vec<_>>();
let has_one_peer = peers.len() == 1;
let mut paths = if !is_recipient_announced {
let mut peer_info = peers
.map(|peer| MessageForwardNode {
short_channel_id: if compact_paths { peer.short_channel_id } else { None },
..peer
})
.filter_map(|peer| {
network_graph
.node(&NodeId::from_pubkey(&peer.node_id))
.map(|info| (peer, info.is_tor_only(), info.channels.len()))
// Allow messages directly with the only peer
.or_else(|| has_one_peer.then(|| (peer, false, 0)))
})
.collect::<Vec<_>>();

// Prefer using non-Tor nodes with the most channels as the introduction node.
peer_info.sort_unstable_by(
|(_, a_tor_only, a_channels), (_, b_tor_only, b_channels)| {
a_tor_only.cmp(b_tor_only).then(a_channels.cmp(b_channels).reverse())
},
);

// Try to create paths from peer info, fall back to direct path if needed
peer_info
.into_iter()
.map(|(peer, _, _)| build_path(&[peer]))
.take(MAX_PATHS)
.collect::<Vec<_>>()
} else {
vec![]
};
Comment on lines +640 to +642

@jkczyzjkczyzJun 2, 2026

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Given we can return more than one path, couldn't we return the 1-hop path (plus dummy hops) in addition to the multi-hop paths? Senders would try all paths, or at least retry over different paths if they don't get a response over the paths requiring a direct connection with an LND node.

@TheBlueMattTheBlueMattJun 8, 2026

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The problem is the BOLT 12 offer creation stuff will pick one path at random (well, currently just the first path, but I'm not sure we want to rely on that at the messagerouter level). Doing this would indeed give us back some privacy for other usecases, but I'm not sure we care as much about hose vs BOLT 12 offers :/.


if paths.is_empty() {
if is_recipient_announced {
paths = vec![build_path(&[])];
Expand Down
, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
 blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

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Stop using an introduction node in blinded message paths#4647

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 Merged

jkczyz
merged 1 commit into

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Jun 8, 2026
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Stop using an introduction node in blinded message paths
#4647
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157 changes: 2 additions & 155 deletions
lightning/src/ln/offers_tests.rs

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Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -56,7 +56,7 @@ use crate::ln::channelmanager::{PaymentId, RecentPaymentDetails, self};
use crate::ln::outbound_payment::{Bolt12PaymentError, RecipientOnionFields, Retry};
use crate::types::features::Bolt12InvoiceFeatures;
use crate::ln::functional_test_utils::*;
use crate::ln::msgs::{BaseMessageHandler, ChannelMessageHandler, Init, NodeAnnouncement, OnionMessage, OnionMessageHandler, RoutingMessageHandler, SocketAddress, UnsignedGossipMessage, UnsignedNodeAnnouncement};
use crate::ln::msgs::{BaseMessageHandler, ChannelMessageHandler, Init, OnionMessage, OnionMessageHandler};
use crate::ln::outbound_payment::IDEMPOTENCY_TIMEOUT_TICKS;
use crate::offers::invoice::Bolt12Invoice;
use crate::offers::invoice_error::InvoiceError;
Expand All@@ -66,9 +66,8 @@ use crate::offers::offer::OfferBuilder;
use crate::offers::parse::Bolt12SemanticError;
use crate::onion_message::messenger::{DefaultMessageRouter, Destination, MessageRouter, MessageSendInstructions, NodeIdMessageRouter, NullMessageRouter, PeeledOnion, DUMMY_HOPS_PATH_LENGTH, QR_CODED_DUMMY_HOPS_PATH_LENGTH};
use crate::onion_message::offers::OffersMessage;
use crate::routing::gossip::{NodeAlias, NodeId};
use crate::routing::router::{DEFAULT_PAYMENT_DUMMY_HOPS, PaymentParameters, RouteParameters, RouteParametersConfig};
use crate::sign::{NodeSigner, Recipient};
use crate::sign::NodeSigner;
use crate::util::ser::Writeable;

/// This used to determine whether we built a compact path or not, but now its just a random
Expand DownExpand Up@@ -125,38 +124,6 @@ fn disconnect_peers<'a, 'b, 'c>(node_a: &Node<'a, 'b, 'c>, peers: &[&Node<'a, 'b
	}
}

fn announce_node_address<'a, 'b, 'c>(
	node: &Node<'a, 'b, 'c>, peers: &[&Node<'a, 'b, 'c>], address: SocketAddress,
) {
	let features = node.onion_messenger.provided_node_features()
 | node.gossip_sync.provided_node_features();
	let rgb = [0u8; 3];
	let announcement = UnsignedNodeAnnouncement {
 features,
 timestamp: 1000,
 node_id: NodeId::from_pubkey(&node.keys_manager.get_node_id(Recipient::Node).unwrap()),
 rgb,
 alias: NodeAlias([0u8; 32]),
 addresses: vec![address],
 excess_address_data: Vec::new(),
 excess_data: Vec::new(),
	};
	let signature = node.keys_manager.sign_gossip_message(
 UnsignedGossipMessage::NodeAnnouncement(&announcement)
	).unwrap();

	let msg = NodeAnnouncement {
 signature,
 contents: announcement
	};

	let node_pubkey = node.node.get_our_node_id();
	node.gossip_sync.handle_node_announcement(None, &msg).unwrap();
	for peer in peers {
 peer.gossip_sync.handle_node_announcement(Some(node_pubkey), &msg).unwrap();
	}
}

fn resolve_introduction_node<'a, 'b, 'c>(node: &Node<'a, 'b, 'c>, path: &BlindedMessagePath) -> PublicKey {
	path.public_introduction_node_id(&node.network_graph.read_only())
 .and_then(|node_id| node_id.as_pubkey().ok())
Expand DownExpand Up@@ -362,126 +329,6 @@ fn create_refund_with_no_blinded_path() {
	assert!(refund.paths().is_empty());
}

/// Checks that blinded paths without Tor-only nodes are preferred when constructing an offer.
#[test]
fn prefers_non_tor_nodes_in_blinded_paths() {
	let mut accept_forward_cfg = test_default_channel_config();
	accept_forward_cfg.accept_forwards_to_priv_channels = true;

	let mut features = channelmanager::provided_init_features(&accept_forward_cfg);
	features.set_onion_messages_optional();
	features.set_route_blinding_optional();

	let chanmon_cfgs = create_chanmon_cfgs(6);
	let node_cfgs = create_node_cfgs(6, &chanmon_cfgs);

	*node_cfgs[1].override_init_features.borrow_mut() = Some(features);

	let node_chanmgrs = create_node_chanmgrs(
 6, &node_cfgs, &[None, Some(accept_forward_cfg), None, None, None, None]
	);
	let nodes = create_network(6, &node_cfgs, &node_chanmgrs);

	create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000_000, 1_000_000_000);
	create_unannounced_chan_between_nodes_with_value(&nodes, 2, 3, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 2, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 5, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 2, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 2, 5, 10_000_000, 1_000_000_000);

	// Add an extra channel so that more than one of Bob's peers have MIN_PEER_CHANNELS.
	create_announced_chan_between_nodes_with_value(&nodes, 4, 5, 10_000_000, 1_000_000_000);

	let (alice, bob, charlie, david) = (&nodes[0], &nodes[1], &nodes[2], &nodes[3]);
	let bob_id = bob.node.get_our_node_id();
	let charlie_id = charlie.node.get_our_node_id();

	disconnect_peers(alice, &[charlie, david, &nodes[4], &nodes[5]]);
	disconnect_peers(david, &[bob, &nodes[4], &nodes[5]]);

	let tor = SocketAddress::OnionV2([255, 254, 253, 252, 251, 250, 249, 248, 247, 246, 38, 7]);
	announce_node_address(charlie, &[alice, bob, david, &nodes[4], &nodes[5]], tor.clone());

	let offer = bob.node
 .create_offer_builder().unwrap()
 .amount_msats(10_000_000)
 .build().unwrap();
	assert_ne!(offer.issuer_signing_pubkey(), Some(bob_id));
	assert!(!offer.paths().is_empty());
	for path in offer.paths() {
 let introduction_node_id = resolve_introduction_node(david, &path);
 assert_ne!(introduction_node_id, bob_id);
 assert_ne!(introduction_node_id, charlie_id);
	}

	// Use a one-hop blinded path when Bob is announced and all his peers are Tor-only.
	announce_node_address(&nodes[4], &[alice, bob, charlie, david, &nodes[5]], tor.clone());
	announce_node_address(&nodes[5], &[alice, bob, charlie, david, &nodes[4]], tor.clone());

	let offer = bob.node
 .create_offer_builder().unwrap()
 .amount_msats(10_000_000)
 .build().unwrap();
	assert_ne!(offer.issuer_signing_pubkey(), Some(bob_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);
	}
}

/// Checks that blinded paths prefer an introduction node that is the most connected.
#[test]
fn prefers_more_connected_nodes_in_blinded_paths() {
	let mut accept_forward_cfg = test_default_channel_config();
	accept_forward_cfg.accept_forwards_to_priv_channels = true;

	let mut features = channelmanager::provided_init_features(&accept_forward_cfg);
	features.set_onion_messages_optional();
	features.set_route_blinding_optional();

	let chanmon_cfgs = create_chanmon_cfgs(6);
	let node_cfgs = create_node_cfgs(6, &chanmon_cfgs);

	*node_cfgs[1].override_init_features.borrow_mut() = Some(features);

	let node_chanmgrs = create_node_chanmgrs(
 6, &node_cfgs, &[None, Some(accept_forward_cfg), None, None, None, None]
	);
	let nodes = create_network(6, &node_cfgs, &node_chanmgrs);

	create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000_000, 1_000_000_000);
	create_unannounced_chan_between_nodes_with_value(&nodes, 2, 3, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 2, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 5, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 2, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 2, 5, 10_000_000, 1_000_000_000);

	// Add extra channels so that more than one of Bob's peers have MIN_PEER_CHANNELS and one has
	// more than the others.
	create_announced_chan_between_nodes_with_value(&nodes, 0, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 3, 4, 10_000_000, 1_000_000_000);

	let (alice, bob, charlie, david) = (&nodes[0], &nodes[1], &nodes[2], &nodes[3]);
	let bob_id = bob.node.get_our_node_id();

	disconnect_peers(alice, &[charlie, david, &nodes[4], &nodes[5]]);
	disconnect_peers(david, &[bob, &nodes[4], &nodes[5]]);

	let offer = bob.node
 .create_offer_builder().unwrap()
 .amount_msats(10_000_000)
 .build().unwrap();
	assert_ne!(offer.issuer_signing_pubkey(), Some(bob_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, nodes[4].node.get_our_node_id());
	}
}

/// Tests the dummy hop behavior of Offers based on the message router used:
/// - Compact paths (`DefaultMessageRouter`) should not include dummy hops.
/// - Node ID paths (`NodeIdMessageRouter`) may include 0 to [`MAX_DUMMY_HOPS_COUNT`] dummy hops.
Expand Down

69 changes: 33 additions & 36 deletions
lightning/src/onion_message/messenger.rs

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Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -563,10 +563,6 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Logger, ES: EntropySource>
 // Limit the number of blinded paths that are computed.
 const MAX_PATHS: usize = 3;

 // Ensure peers have at least three channels so that it is more difficult to infer the
 // recipient's node_id.
 const MIN_PEER_CHANNELS: usize = 3;

 let network_graph = network_graph.deref().read_only();
 let is_recipient_announced =
 network_graph.nodes().contains_key(&NodeId::from_pubkey(&recipient));
Expand DownExpand Up@@ -596,32 +592,6 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Logger, ES: EntropySource>

 let compact_paths = !never_compact_path && size_constrained;

 let has_one_peer = peers.len() == 1;
 let mut peer_info = peers
 .map(|peer| MessageForwardNode {
 short_channel_id: if compact_paths { peer.short_channel_id } else { None },
 ..peer
 })
 // Limit to peers with announced channels unless the recipient is unannounced.
 .filter_map(|peer| {
 network_graph
 .node(&NodeId::from_pubkey(&peer.node_id))
 .filter(|info| {
 !is_recipient_announced || info.channels.len() >= MIN_PEER_CHANNELS
 })
 .map(|info| (peer, info.is_tor_only(), info.channels.len()))
 // Allow messages directly with the only peer when unannounced.
 .or_else(|| (!is_recipient_announced && has_one_peer).then(|| (peer, false, 0)))
 })
 // Exclude Tor-only nodes when the recipient is announced.
 .filter(|(_, is_tor_only, _)| !(*is_tor_only && is_recipient_announced))
 .collect::<Vec<_>>();

 // Prefer using non-Tor nodes with the most channels as the introduction node.
 peer_info.sort_unstable_by(|(_, a_tor_only, a_channels), (_, b_tor_only, b_channels)| {
 a_tor_only.cmp(b_tor_only).then(a_channels.cmp(b_channels).reverse())
 });

 let build_path = |intermediate_hops: &[MessageForwardNode]| {
 // Calculate the dummy hops given the total hop count target (including the recipient).
 let dummy_hops_count = path_len_incl_dummys.saturating_sub(intermediate_hops.len() + 1);
Expand All@@ -638,12 +608,39 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Logger, ES: EntropySource>
 )
 };

 // Try to create paths from peer info, fall back to direct path if needed
 let mut paths = peer_info
 .into_iter()
 .map(|(peer, _, _)| build_path(&[peer]))
 .take(MAX_PATHS)
 .collect::<Vec<_>>();
 let has_one_peer = peers.len() == 1;
 let mut paths = if !is_recipient_announced {
 let mut peer_info = peers
 .map(|peer| MessageForwardNode {
 short_channel_id: if compact_paths { peer.short_channel_id } else { None },
 ..peer
 })
 .filter_map(|peer| {
 network_graph
 .node(&NodeId::from_pubkey(&peer.node_id))
 .map(|info| (peer, info.is_tor_only(), info.channels.len()))
 // Allow messages directly with the only peer
 .or_else(|| has_one_peer.then(|| (peer, false, 0)))
 })
 .collect::<Vec<_>>();

 // Prefer using non-Tor nodes with the most channels as the introduction node.
 peer_info.sort_unstable_by(
 |(_, a_tor_only, a_channels), (_, b_tor_only, b_channels)| {
 a_tor_only.cmp(b_tor_only).then(a_channels.cmp(b_channels).reverse())
 },
 );

 // Try to create paths from peer info, fall back to direct path if needed
 peer_info
 .into_iter()
 .map(|(peer, _, _)| build_path(&[peer]))
 .take(MAX_PATHS)
 .collect::<Vec<_>>()
 } else {
 vec![]
 };

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@jkczyzjkczyzJun 2, 2026

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Given we can return more than one path, couldn't we return the 1-hop path (plus dummy hops) in addition to the multi-hop paths? Senders would try all paths, or at least retry over different paths if they don't get a response over the paths requiring a direct connection with an LND node.
@TheBlueMattTheBlueMattJun 8, 2026

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The problem is the BOLT 12 offer creation stuff will pick one path at random (well, currently just the first path, but I'm not sure we want to rely on that at the messagerouter level). Doing this would indeed give us back some privacy for other usecases, but I'm not sure we care as much about hose vs BOLT 12 offers :/.

 if paths.is_empty() {
 if is_recipient_announced {
 paths = vec![build_path(&[])];
Expand Down

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Jun 8, 2026
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Stop using an introduction node in blinded message paths
#4647
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157 changes: 2 additions & 155 deletions
lightning/src/ln/offers_tests.rs

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Original file line numberDiff line numberDiff line change
Expand Up@@ -56,7 +56,7 @@ use crate::ln::channelmanager::{PaymentId, RecentPaymentDetails, self};
use crate::ln::outbound_payment::{Bolt12PaymentError, RecipientOnionFields, Retry};
use crate::types::features::Bolt12InvoiceFeatures;
use crate::ln::functional_test_utils::*;
use crate::ln::msgs::{BaseMessageHandler, ChannelMessageHandler, Init, NodeAnnouncement, OnionMessage, OnionMessageHandler, RoutingMessageHandler, SocketAddress, UnsignedGossipMessage, UnsignedNodeAnnouncement};
use crate::ln::msgs::{BaseMessageHandler, ChannelMessageHandler, Init, OnionMessage, OnionMessageHandler};
use crate::ln::outbound_payment::IDEMPOTENCY_TIMEOUT_TICKS;
use crate::offers::invoice::Bolt12Invoice;
use crate::offers::invoice_error::InvoiceError;
Expand All@@ -66,9 +66,8 @@ use crate::offers::offer::OfferBuilder;
use crate::offers::parse::Bolt12SemanticError;
use crate::onion_message::messenger::{DefaultMessageRouter, Destination, MessageRouter, MessageSendInstructions, NodeIdMessageRouter, NullMessageRouter, PeeledOnion, DUMMY_HOPS_PATH_LENGTH, QR_CODED_DUMMY_HOPS_PATH_LENGTH};
use crate::onion_message::offers::OffersMessage;
use crate::routing::gossip::{NodeAlias, NodeId};
use crate::routing::router::{DEFAULT_PAYMENT_DUMMY_HOPS, PaymentParameters, RouteParameters, RouteParametersConfig};
use crate::sign::{NodeSigner, Recipient};
use crate::sign::NodeSigner;
use crate::util::ser::Writeable;

/// This used to determine whether we built a compact path or not, but now its just a random
Expand DownExpand Up@@ -125,38 +124,6 @@ fn disconnect_peers<'a, 'b, 'c>(node_a: &Node<'a, 'b, 'c>, peers: &[&Node<'a, 'b
	}
}

fn announce_node_address<'a, 'b, 'c>(
	node: &Node<'a, 'b, 'c>, peers: &[&Node<'a, 'b, 'c>], address: SocketAddress,
) {
	let features = node.onion_messenger.provided_node_features()
 | node.gossip_sync.provided_node_features();
	let rgb = [0u8; 3];
	let announcement = UnsignedNodeAnnouncement {
 features,
 timestamp: 1000,
 node_id: NodeId::from_pubkey(&node.keys_manager.get_node_id(Recipient::Node).unwrap()),
 rgb,
 alias: NodeAlias([0u8; 32]),
 addresses: vec![address],
 excess_address_data: Vec::new(),
 excess_data: Vec::new(),
	};
	let signature = node.keys_manager.sign_gossip_message(
 UnsignedGossipMessage::NodeAnnouncement(&announcement)
	).unwrap();

	let msg = NodeAnnouncement {
 signature,
 contents: announcement
	};

	let node_pubkey = node.node.get_our_node_id();
	node.gossip_sync.handle_node_announcement(None, &msg).unwrap();
	for peer in peers {
 peer.gossip_sync.handle_node_announcement(Some(node_pubkey), &msg).unwrap();
	}
}

fn resolve_introduction_node<'a, 'b, 'c>(node: &Node<'a, 'b, 'c>, path: &BlindedMessagePath) -> PublicKey {
	path.public_introduction_node_id(&node.network_graph.read_only())
 .and_then(|node_id| node_id.as_pubkey().ok())
Expand DownExpand Up@@ -362,126 +329,6 @@ fn create_refund_with_no_blinded_path() {
	assert!(refund.paths().is_empty());
}

/// Checks that blinded paths without Tor-only nodes are preferred when constructing an offer.
#[test]
fn prefers_non_tor_nodes_in_blinded_paths() {
	let mut accept_forward_cfg = test_default_channel_config();
	accept_forward_cfg.accept_forwards_to_priv_channels = true;

	let mut features = channelmanager::provided_init_features(&accept_forward_cfg);
	features.set_onion_messages_optional();
	features.set_route_blinding_optional();

	let chanmon_cfgs = create_chanmon_cfgs(6);
	let node_cfgs = create_node_cfgs(6, &chanmon_cfgs);

	*node_cfgs[1].override_init_features.borrow_mut() = Some(features);

	let node_chanmgrs = create_node_chanmgrs(
 6, &node_cfgs, &[None, Some(accept_forward_cfg), None, None, None, None]
	);
	let nodes = create_network(6, &node_cfgs, &node_chanmgrs);

	create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000_000, 1_000_000_000);
	create_unannounced_chan_between_nodes_with_value(&nodes, 2, 3, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 2, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 5, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 2, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 2, 5, 10_000_000, 1_000_000_000);

	// Add an extra channel so that more than one of Bob's peers have MIN_PEER_CHANNELS.
	create_announced_chan_between_nodes_with_value(&nodes, 4, 5, 10_000_000, 1_000_000_000);

	let (alice, bob, charlie, david) = (&nodes[0], &nodes[1], &nodes[2], &nodes[3]);
	let bob_id = bob.node.get_our_node_id();
	let charlie_id = charlie.node.get_our_node_id();

	disconnect_peers(alice, &[charlie, david, &nodes[4], &nodes[5]]);
	disconnect_peers(david, &[bob, &nodes[4], &nodes[5]]);

	let tor = SocketAddress::OnionV2([255, 254, 253, 252, 251, 250, 249, 248, 247, 246, 38, 7]);
	announce_node_address(charlie, &[alice, bob, david, &nodes[4], &nodes[5]], tor.clone());

	let offer = bob.node
 .create_offer_builder().unwrap()
 .amount_msats(10_000_000)
 .build().unwrap();
	assert_ne!(offer.issuer_signing_pubkey(), Some(bob_id));
	assert!(!offer.paths().is_empty());
	for path in offer.paths() {
 let introduction_node_id = resolve_introduction_node(david, &path);
 assert_ne!(introduction_node_id, bob_id);
 assert_ne!(introduction_node_id, charlie_id);
	}

	// Use a one-hop blinded path when Bob is announced and all his peers are Tor-only.
	announce_node_address(&nodes[4], &[alice, bob, charlie, david, &nodes[5]], tor.clone());
	announce_node_address(&nodes[5], &[alice, bob, charlie, david, &nodes[4]], tor.clone());

	let offer = bob.node
 .create_offer_builder().unwrap()
 .amount_msats(10_000_000)
 .build().unwrap();
	assert_ne!(offer.issuer_signing_pubkey(), Some(bob_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);
	}
}

/// Checks that blinded paths prefer an introduction node that is the most connected.
#[test]
fn prefers_more_connected_nodes_in_blinded_paths() {
	let mut accept_forward_cfg = test_default_channel_config();
	accept_forward_cfg.accept_forwards_to_priv_channels = true;

	let mut features = channelmanager::provided_init_features(&accept_forward_cfg);
	features.set_onion_messages_optional();
	features.set_route_blinding_optional();

	let chanmon_cfgs = create_chanmon_cfgs(6);
	let node_cfgs = create_node_cfgs(6, &chanmon_cfgs);

	*node_cfgs[1].override_init_features.borrow_mut() = Some(features);

	let node_chanmgrs = create_node_chanmgrs(
 6, &node_cfgs, &[None, Some(accept_forward_cfg), None, None, None, None]
	);
	let nodes = create_network(6, &node_cfgs, &node_chanmgrs);

	create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000_000, 1_000_000_000);
	create_unannounced_chan_between_nodes_with_value(&nodes, 2, 3, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 2, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 5, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 2, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 2, 5, 10_000_000, 1_000_000_000);

	// Add extra channels so that more than one of Bob's peers have MIN_PEER_CHANNELS and one has
	// more than the others.
	create_announced_chan_between_nodes_with_value(&nodes, 0, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 3, 4, 10_000_000, 1_000_000_000);

	let (alice, bob, charlie, david) = (&nodes[0], &nodes[1], &nodes[2], &nodes[3]);
	let bob_id = bob.node.get_our_node_id();

	disconnect_peers(alice, &[charlie, david, &nodes[4], &nodes[5]]);
	disconnect_peers(david, &[bob, &nodes[4], &nodes[5]]);

	let offer = bob.node
 .create_offer_builder().unwrap()
 .amount_msats(10_000_000)
 .build().unwrap();
	assert_ne!(offer.issuer_signing_pubkey(), Some(bob_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, nodes[4].node.get_our_node_id());
	}
}

/// Tests the dummy hop behavior of Offers based on the message router used:
/// - Compact paths (`DefaultMessageRouter`) should not include dummy hops.
/// - Node ID paths (`NodeIdMessageRouter`) may include 0 to [`MAX_DUMMY_HOPS_COUNT`] dummy hops.
Expand Down

69 changes: 33 additions & 36 deletions
lightning/src/onion_message/messenger.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -563,10 +563,6 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Logger, ES: EntropySource>
 // Limit the number of blinded paths that are computed.
 const MAX_PATHS: usize = 3;

 // Ensure peers have at least three channels so that it is more difficult to infer the
 // recipient's node_id.
 const MIN_PEER_CHANNELS: usize = 3;

 let network_graph = network_graph.deref().read_only();
 let is_recipient_announced =
 network_graph.nodes().contains_key(&NodeId::from_pubkey(&recipient));
Expand DownExpand Up@@ -596,32 +592,6 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Logger, ES: EntropySource>

 let compact_paths = !never_compact_path && size_constrained;

 let has_one_peer = peers.len() == 1;
 let mut peer_info = peers
 .map(|peer| MessageForwardNode {
 short_channel_id: if compact_paths { peer.short_channel_id } else { None },
 ..peer
 })
 // Limit to peers with announced channels unless the recipient is unannounced.
 .filter_map(|peer| {
 network_graph
 .node(&NodeId::from_pubkey(&peer.node_id))
 .filter(|info| {
 !is_recipient_announced || info.channels.len() >= MIN_PEER_CHANNELS
 })
 .map(|info| (peer, info.is_tor_only(), info.channels.len()))
 // Allow messages directly with the only peer when unannounced.
 .or_else(|| (!is_recipient_announced && has_one_peer).then(|| (peer, false, 0)))
 })
 // Exclude Tor-only nodes when the recipient is announced.
 .filter(|(_, is_tor_only, _)| !(*is_tor_only && is_recipient_announced))
 .collect::<Vec<_>>();

 // Prefer using non-Tor nodes with the most channels as the introduction node.
 peer_info.sort_unstable_by(|(_, a_tor_only, a_channels), (_, b_tor_only, b_channels)| {
 a_tor_only.cmp(b_tor_only).then(a_channels.cmp(b_channels).reverse())
 });

 let build_path = |intermediate_hops: &[MessageForwardNode]| {
 // Calculate the dummy hops given the total hop count target (including the recipient).
 let dummy_hops_count = path_len_incl_dummys.saturating_sub(intermediate_hops.len() + 1);
Expand All@@ -638,12 +608,39 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Logger, ES: EntropySource>
 )
 };

 // Try to create paths from peer info, fall back to direct path if needed
 let mut paths = peer_info
 .into_iter()
 .map(|(peer, _, _)| build_path(&[peer]))
 .take(MAX_PATHS)
 .collect::<Vec<_>>();
 let has_one_peer = peers.len() == 1;
 let mut paths = if !is_recipient_announced {
 let mut peer_info = peers
 .map(|peer| MessageForwardNode {
 short_channel_id: if compact_paths { peer.short_channel_id } else { None },
 ..peer
 })
 .filter_map(|peer| {
 network_graph
 .node(&NodeId::from_pubkey(&peer.node_id))
 .map(|info| (peer, info.is_tor_only(), info.channels.len()))
 // Allow messages directly with the only peer
 .or_else(|| has_one_peer.then(|| (peer, false, 0)))
 })
 .collect::<Vec<_>>();

 // Prefer using non-Tor nodes with the most channels as the introduction node.
 peer_info.sort_unstable_by(
 |(_, a_tor_only, a_channels), (_, b_tor_only, b_channels)| {
 a_tor_only.cmp(b_tor_only).then(a_channels.cmp(b_channels).reverse())
 },
 );

 // Try to create paths from peer info, fall back to direct path if needed
 peer_info
 .into_iter()
 .map(|(peer, _, _)| build_path(&[peer]))
 .take(MAX_PATHS)
 .collect::<Vec<_>>()
 } else {
 vec![]
 };

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+642

@jkczyzjkczyzJun 2, 2026

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Given we can return more than one path, couldn't we return the 1-hop path (plus dummy hops) in addition to the multi-hop paths? Senders would try all paths, or at least retry over different paths if they don't get a response over the paths requiring a direct connection with an LND node.
@TheBlueMattTheBlueMattJun 8, 2026

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The problem is the BOLT 12 offer creation stuff will pick one path at random (well, currently just the first path, but I'm not sure we want to rely on that at the messagerouter level). Doing this would indeed give us back some privacy for other usecases, but I'm not sure we care as much about hose vs BOLT 12 offers :/.

 if paths.is_empty() {
 if is_recipient_announced {
 paths = vec![build_path(&[])];
Expand Down

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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Stop using an introduction node in blinded message paths#4647

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jkczyz
merged 1 commit into

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Jun 8, 2026
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Stop using an introduction node in blinded message paths
#4647
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157 changes: 2 additions & 155 deletions
lightning/src/ln/offers_tests.rs

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Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -56,7 +56,7 @@ use crate::ln::channelmanager::{PaymentId, RecentPaymentDetails, self};
use crate::ln::outbound_payment::{Bolt12PaymentError, RecipientOnionFields, Retry};
use crate::types::features::Bolt12InvoiceFeatures;
use crate::ln::functional_test_utils::*;
use crate::ln::msgs::{BaseMessageHandler, ChannelMessageHandler, Init, NodeAnnouncement, OnionMessage, OnionMessageHandler, RoutingMessageHandler, SocketAddress, UnsignedGossipMessage, UnsignedNodeAnnouncement};
use crate::ln::msgs::{BaseMessageHandler, ChannelMessageHandler, Init, OnionMessage, OnionMessageHandler};
use crate::ln::outbound_payment::IDEMPOTENCY_TIMEOUT_TICKS;
use crate::offers::invoice::Bolt12Invoice;
use crate::offers::invoice_error::InvoiceError;
Expand All@@ -66,9 +66,8 @@ use crate::offers::offer::OfferBuilder;
use crate::offers::parse::Bolt12SemanticError;
use crate::onion_message::messenger::{DefaultMessageRouter, Destination, MessageRouter, MessageSendInstructions, NodeIdMessageRouter, NullMessageRouter, PeeledOnion, DUMMY_HOPS_PATH_LENGTH, QR_CODED_DUMMY_HOPS_PATH_LENGTH};
use crate::onion_message::offers::OffersMessage;
use crate::routing::gossip::{NodeAlias, NodeId};
use crate::routing::router::{DEFAULT_PAYMENT_DUMMY_HOPS, PaymentParameters, RouteParameters, RouteParametersConfig};
use crate::sign::{NodeSigner, Recipient};
use crate::sign::NodeSigner;
use crate::util::ser::Writeable;

/// This used to determine whether we built a compact path or not, but now its just a random
Expand DownExpand Up@@ -125,38 +124,6 @@ fn disconnect_peers<'a, 'b, 'c>(node_a: &Node<'a, 'b, 'c>, peers: &[&Node<'a, 'b
	}
}

fn announce_node_address<'a, 'b, 'c>(
	node: &Node<'a, 'b, 'c>, peers: &[&Node<'a, 'b, 'c>], address: SocketAddress,
) {
	let features = node.onion_messenger.provided_node_features()
 | node.gossip_sync.provided_node_features();
	let rgb = [0u8; 3];
	let announcement = UnsignedNodeAnnouncement {
 features,
 timestamp: 1000,
 node_id: NodeId::from_pubkey(&node.keys_manager.get_node_id(Recipient::Node).unwrap()),
 rgb,
 alias: NodeAlias([0u8; 32]),
 addresses: vec![address],
 excess_address_data: Vec::new(),
 excess_data: Vec::new(),
	};
	let signature = node.keys_manager.sign_gossip_message(
 UnsignedGossipMessage::NodeAnnouncement(&announcement)
	).unwrap();

	let msg = NodeAnnouncement {
 signature,
 contents: announcement
	};

	let node_pubkey = node.node.get_our_node_id();
	node.gossip_sync.handle_node_announcement(None, &msg).unwrap();
	for peer in peers {
 peer.gossip_sync.handle_node_announcement(Some(node_pubkey), &msg).unwrap();
	}
}

fn resolve_introduction_node<'a, 'b, 'c>(node: &Node<'a, 'b, 'c>, path: &BlindedMessagePath) -> PublicKey {
	path.public_introduction_node_id(&node.network_graph.read_only())
 .and_then(|node_id| node_id.as_pubkey().ok())
Expand DownExpand Up@@ -362,126 +329,6 @@ fn create_refund_with_no_blinded_path() {
	assert!(refund.paths().is_empty());
}

/// Checks that blinded paths without Tor-only nodes are preferred when constructing an offer.
#[test]
fn prefers_non_tor_nodes_in_blinded_paths() {
	let mut accept_forward_cfg = test_default_channel_config();
	accept_forward_cfg.accept_forwards_to_priv_channels = true;

	let mut features = channelmanager::provided_init_features(&accept_forward_cfg);
	features.set_onion_messages_optional();
	features.set_route_blinding_optional();

	let chanmon_cfgs = create_chanmon_cfgs(6);
	let node_cfgs = create_node_cfgs(6, &chanmon_cfgs);

	*node_cfgs[1].override_init_features.borrow_mut() = Some(features);

	let node_chanmgrs = create_node_chanmgrs(
 6, &node_cfgs, &[None, Some(accept_forward_cfg), None, None, None, None]
	);
	let nodes = create_network(6, &node_cfgs, &node_chanmgrs);

	create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000_000, 1_000_000_000);
	create_unannounced_chan_between_nodes_with_value(&nodes, 2, 3, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 2, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 5, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 2, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 2, 5, 10_000_000, 1_000_000_000);

	// Add an extra channel so that more than one of Bob's peers have MIN_PEER_CHANNELS.
	create_announced_chan_between_nodes_with_value(&nodes, 4, 5, 10_000_000, 1_000_000_000);

	let (alice, bob, charlie, david) = (&nodes[0], &nodes[1], &nodes[2], &nodes[3]);
	let bob_id = bob.node.get_our_node_id();
	let charlie_id = charlie.node.get_our_node_id();

	disconnect_peers(alice, &[charlie, david, &nodes[4], &nodes[5]]);
	disconnect_peers(david, &[bob, &nodes[4], &nodes[5]]);

	let tor = SocketAddress::OnionV2([255, 254, 253, 252, 251, 250, 249, 248, 247, 246, 38, 7]);
	announce_node_address(charlie, &[alice, bob, david, &nodes[4], &nodes[5]], tor.clone());

	let offer = bob.node
 .create_offer_builder().unwrap()
 .amount_msats(10_000_000)
 .build().unwrap();
	assert_ne!(offer.issuer_signing_pubkey(), Some(bob_id));
	assert!(!offer.paths().is_empty());
	for path in offer.paths() {
 let introduction_node_id = resolve_introduction_node(david, &path);
 assert_ne!(introduction_node_id, bob_id);
 assert_ne!(introduction_node_id, charlie_id);
	}

	// Use a one-hop blinded path when Bob is announced and all his peers are Tor-only.
	announce_node_address(&nodes[4], &[alice, bob, charlie, david, &nodes[5]], tor.clone());
	announce_node_address(&nodes[5], &[alice, bob, charlie, david, &nodes[4]], tor.clone());

	let offer = bob.node
 .create_offer_builder().unwrap()
 .amount_msats(10_000_000)
 .build().unwrap();
	assert_ne!(offer.issuer_signing_pubkey(), Some(bob_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);
	}
}

/// Checks that blinded paths prefer an introduction node that is the most connected.
#[test]
fn prefers_more_connected_nodes_in_blinded_paths() {
	let mut accept_forward_cfg = test_default_channel_config();
	accept_forward_cfg.accept_forwards_to_priv_channels = true;

	let mut features = channelmanager::provided_init_features(&accept_forward_cfg);
	features.set_onion_messages_optional();
	features.set_route_blinding_optional();

	let chanmon_cfgs = create_chanmon_cfgs(6);
	let node_cfgs = create_node_cfgs(6, &chanmon_cfgs);

	*node_cfgs[1].override_init_features.borrow_mut() = Some(features);

	let node_chanmgrs = create_node_chanmgrs(
 6, &node_cfgs, &[None, Some(accept_forward_cfg), None, None, None, None]
	);
	let nodes = create_network(6, &node_cfgs, &node_chanmgrs);

	create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000_000, 1_000_000_000);
	create_unannounced_chan_between_nodes_with_value(&nodes, 2, 3, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 2, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 5, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 2, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 2, 5, 10_000_000, 1_000_000_000);

	// Add extra channels so that more than one of Bob's peers have MIN_PEER_CHANNELS and one has
	// more than the others.
	create_announced_chan_between_nodes_with_value(&nodes, 0, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 3, 4, 10_000_000, 1_000_000_000);

	let (alice, bob, charlie, david) = (&nodes[0], &nodes[1], &nodes[2], &nodes[3]);
	let bob_id = bob.node.get_our_node_id();

	disconnect_peers(alice, &[charlie, david, &nodes[4], &nodes[5]]);
	disconnect_peers(david, &[bob, &nodes[4], &nodes[5]]);

	let offer = bob.node
 .create_offer_builder().unwrap()
 .amount_msats(10_000_000)
 .build().unwrap();
	assert_ne!(offer.issuer_signing_pubkey(), Some(bob_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, nodes[4].node.get_our_node_id());
	}
}

/// Tests the dummy hop behavior of Offers based on the message router used:
/// - Compact paths (`DefaultMessageRouter`) should not include dummy hops.
/// - Node ID paths (`NodeIdMessageRouter`) may include 0 to [`MAX_DUMMY_HOPS_COUNT`] dummy hops.
Expand Down

69 changes: 33 additions & 36 deletions
lightning/src/onion_message/messenger.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -563,10 +563,6 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Logger, ES: EntropySource>
 // Limit the number of blinded paths that are computed.
 const MAX_PATHS: usize = 3;

 // Ensure peers have at least three channels so that it is more difficult to infer the
 // recipient's node_id.
 const MIN_PEER_CHANNELS: usize = 3;

 let network_graph = network_graph.deref().read_only();
 let is_recipient_announced =
 network_graph.nodes().contains_key(&NodeId::from_pubkey(&recipient));
Expand DownExpand Up@@ -596,32 +592,6 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Logger, ES: EntropySource>

 let compact_paths = !never_compact_path && size_constrained;

 let has_one_peer = peers.len() == 1;
 let mut peer_info = peers
 .map(|peer| MessageForwardNode {
 short_channel_id: if compact_paths { peer.short_channel_id } else { None },
 ..peer
 })
 // Limit to peers with announced channels unless the recipient is unannounced.
 .filter_map(|peer| {
 network_graph
 .node(&NodeId::from_pubkey(&peer.node_id))
 .filter(|info| {
 !is_recipient_announced || info.channels.len() >= MIN_PEER_CHANNELS
 })
 .map(|info| (peer, info.is_tor_only(), info.channels.len()))
 // Allow messages directly with the only peer when unannounced.
 .or_else(|| (!is_recipient_announced && has_one_peer).then(|| (peer, false, 0)))
 })
 // Exclude Tor-only nodes when the recipient is announced.
 .filter(|(_, is_tor_only, _)| !(*is_tor_only && is_recipient_announced))
 .collect::<Vec<_>>();

 // Prefer using non-Tor nodes with the most channels as the introduction node.
 peer_info.sort_unstable_by(|(_, a_tor_only, a_channels), (_, b_tor_only, b_channels)| {
 a_tor_only.cmp(b_tor_only).then(a_channels.cmp(b_channels).reverse())
 });

 let build_path = |intermediate_hops: &[MessageForwardNode]| {
 // Calculate the dummy hops given the total hop count target (including the recipient).
 let dummy_hops_count = path_len_incl_dummys.saturating_sub(intermediate_hops.len() + 1);
Expand All@@ -638,12 +608,39 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Logger, ES: EntropySource>
 )
 };

 // Try to create paths from peer info, fall back to direct path if needed
 let mut paths = peer_info
 .into_iter()
 .map(|(peer, _, _)| build_path(&[peer]))
 .take(MAX_PATHS)
 .collect::<Vec<_>>();
 let has_one_peer = peers.len() == 1;
 let mut paths = if !is_recipient_announced {
 let mut peer_info = peers
 .map(|peer| MessageForwardNode {
 short_channel_id: if compact_paths { peer.short_channel_id } else { None },
 ..peer
 })
 .filter_map(|peer| {
 network_graph
 .node(&NodeId::from_pubkey(&peer.node_id))
 .map(|info| (peer, info.is_tor_only(), info.channels.len()))
 // Allow messages directly with the only peer
 .or_else(|| has_one_peer.then(|| (peer, false, 0)))
 })
 .collect::<Vec<_>>();

 // Prefer using non-Tor nodes with the most channels as the introduction node.
 peer_info.sort_unstable_by(
 |(_, a_tor_only, a_channels), (_, b_tor_only, b_channels)| {
 a_tor_only.cmp(b_tor_only).then(a_channels.cmp(b_channels).reverse())
 },
 );

 // Try to create paths from peer info, fall back to direct path if needed
 peer_info
 .into_iter()
 .map(|(peer, _, _)| build_path(&[peer]))
 .take(MAX_PATHS)
 .collect::<Vec<_>>()
 } else {
 vec![]
 };

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+642

@jkczyzjkczyzJun 2, 2026

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Given we can return more than one path, couldn't we return the 1-hop path (plus dummy hops) in addition to the multi-hop paths? Senders would try all paths, or at least retry over different paths if they don't get a response over the paths requiring a direct connection with an LND node.
@TheBlueMattTheBlueMattJun 8, 2026

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The problem is the BOLT 12 offer creation stuff will pick one path at random (well, currently just the first path, but I'm not sure we want to rely on that at the messagerouter level). Doing this would indeed give us back some privacy for other usecases, but I'm not sure we care as much about hose vs BOLT 12 offers :/.

 if paths.is_empty() {
 if is_recipient_announced {
 paths = vec![build_path(&[])];
Expand Down

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

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Stop using an introduction node in blinded message paths#4647

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 Merged

jkczyz
merged 1 commit into

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Jun 8, 2026
 Merged


Stop using an introduction node in blinded message paths
#4647
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157 changes: 2 additions & 155 deletions
lightning/src/ln/offers_tests.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -56,7 +56,7 @@ use crate::ln::channelmanager::{PaymentId, RecentPaymentDetails, self};
use crate::ln::outbound_payment::{Bolt12PaymentError, RecipientOnionFields, Retry};
use crate::types::features::Bolt12InvoiceFeatures;
use crate::ln::functional_test_utils::*;
use crate::ln::msgs::{BaseMessageHandler, ChannelMessageHandler, Init, NodeAnnouncement, OnionMessage, OnionMessageHandler, RoutingMessageHandler, SocketAddress, UnsignedGossipMessage, UnsignedNodeAnnouncement};
use crate::ln::msgs::{BaseMessageHandler, ChannelMessageHandler, Init, OnionMessage, OnionMessageHandler};
use crate::ln::outbound_payment::IDEMPOTENCY_TIMEOUT_TICKS;
use crate::offers::invoice::Bolt12Invoice;
use crate::offers::invoice_error::InvoiceError;
Expand All@@ -66,9 +66,8 @@ use crate::offers::offer::OfferBuilder;
use crate::offers::parse::Bolt12SemanticError;
use crate::onion_message::messenger::{DefaultMessageRouter, Destination, MessageRouter, MessageSendInstructions, NodeIdMessageRouter, NullMessageRouter, PeeledOnion, DUMMY_HOPS_PATH_LENGTH, QR_CODED_DUMMY_HOPS_PATH_LENGTH};
use crate::onion_message::offers::OffersMessage;
use crate::routing::gossip::{NodeAlias, NodeId};
use crate::routing::router::{DEFAULT_PAYMENT_DUMMY_HOPS, PaymentParameters, RouteParameters, RouteParametersConfig};
use crate::sign::{NodeSigner, Recipient};
use crate::sign::NodeSigner;
use crate::util::ser::Writeable;

/// This used to determine whether we built a compact path or not, but now its just a random
Expand DownExpand Up@@ -125,38 +124,6 @@ fn disconnect_peers<'a, 'b, 'c>(node_a: &Node<'a, 'b, 'c>, peers: &[&Node<'a, 'b
	}
}

fn announce_node_address<'a, 'b, 'c>(
	node: &Node<'a, 'b, 'c>, peers: &[&Node<'a, 'b, 'c>], address: SocketAddress,
) {
	let features = node.onion_messenger.provided_node_features()
 | node.gossip_sync.provided_node_features();
	let rgb = [0u8; 3];
	let announcement = UnsignedNodeAnnouncement {
 features,
 timestamp: 1000,
 node_id: NodeId::from_pubkey(&node.keys_manager.get_node_id(Recipient::Node).unwrap()),
 rgb,
 alias: NodeAlias([0u8; 32]),
 addresses: vec![address],
 excess_address_data: Vec::new(),
 excess_data: Vec::new(),
	};
	let signature = node.keys_manager.sign_gossip_message(
 UnsignedGossipMessage::NodeAnnouncement(&announcement)
	).unwrap();

	let msg = NodeAnnouncement {
 signature,
 contents: announcement
	};

	let node_pubkey = node.node.get_our_node_id();
	node.gossip_sync.handle_node_announcement(None, &msg).unwrap();
	for peer in peers {
 peer.gossip_sync.handle_node_announcement(Some(node_pubkey), &msg).unwrap();
	}
}

fn resolve_introduction_node<'a, 'b, 'c>(node: &Node<'a, 'b, 'c>, path: &BlindedMessagePath) -> PublicKey {
	path.public_introduction_node_id(&node.network_graph.read_only())
 .and_then(|node_id| node_id.as_pubkey().ok())
Expand DownExpand Up@@ -362,126 +329,6 @@ fn create_refund_with_no_blinded_path() {
	assert!(refund.paths().is_empty());
}

/// Checks that blinded paths without Tor-only nodes are preferred when constructing an offer.
#[test]
fn prefers_non_tor_nodes_in_blinded_paths() {
	let mut accept_forward_cfg = test_default_channel_config();
	accept_forward_cfg.accept_forwards_to_priv_channels = true;

	let mut features = channelmanager::provided_init_features(&accept_forward_cfg);
	features.set_onion_messages_optional();
	features.set_route_blinding_optional();

	let chanmon_cfgs = create_chanmon_cfgs(6);
	let node_cfgs = create_node_cfgs(6, &chanmon_cfgs);

	*node_cfgs[1].override_init_features.borrow_mut() = Some(features);

	let node_chanmgrs = create_node_chanmgrs(
 6, &node_cfgs, &[None, Some(accept_forward_cfg), None, None, None, None]
	);
	let nodes = create_network(6, &node_cfgs, &node_chanmgrs);

	create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000_000, 1_000_000_000);
	create_unannounced_chan_between_nodes_with_value(&nodes, 2, 3, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 2, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 5, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 2, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 2, 5, 10_000_000, 1_000_000_000);

	// Add an extra channel so that more than one of Bob's peers have MIN_PEER_CHANNELS.
	create_announced_chan_between_nodes_with_value(&nodes, 4, 5, 10_000_000, 1_000_000_000);

	let (alice, bob, charlie, david) = (&nodes[0], &nodes[1], &nodes[2], &nodes[3]);
	let bob_id = bob.node.get_our_node_id();
	let charlie_id = charlie.node.get_our_node_id();

	disconnect_peers(alice, &[charlie, david, &nodes[4], &nodes[5]]);
	disconnect_peers(david, &[bob, &nodes[4], &nodes[5]]);

	let tor = SocketAddress::OnionV2([255, 254, 253, 252, 251, 250, 249, 248, 247, 246, 38, 7]);
	announce_node_address(charlie, &[alice, bob, david, &nodes[4], &nodes[5]], tor.clone());

	let offer = bob.node
 .create_offer_builder().unwrap()
 .amount_msats(10_000_000)
 .build().unwrap();
	assert_ne!(offer.issuer_signing_pubkey(), Some(bob_id));
	assert!(!offer.paths().is_empty());
	for path in offer.paths() {
 let introduction_node_id = resolve_introduction_node(david, &path);
 assert_ne!(introduction_node_id, bob_id);
 assert_ne!(introduction_node_id, charlie_id);
	}

	// Use a one-hop blinded path when Bob is announced and all his peers are Tor-only.
	announce_node_address(&nodes[4], &[alice, bob, charlie, david, &nodes[5]], tor.clone());
	announce_node_address(&nodes[5], &[alice, bob, charlie, david, &nodes[4]], tor.clone());

	let offer = bob.node
 .create_offer_builder().unwrap()
 .amount_msats(10_000_000)
 .build().unwrap();
	assert_ne!(offer.issuer_signing_pubkey(), Some(bob_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);
	}
}

/// Checks that blinded paths prefer an introduction node that is the most connected.
#[test]
fn prefers_more_connected_nodes_in_blinded_paths() {
	let mut accept_forward_cfg = test_default_channel_config();
	accept_forward_cfg.accept_forwards_to_priv_channels = true;

	let mut features = channelmanager::provided_init_features(&accept_forward_cfg);
	features.set_onion_messages_optional();
	features.set_route_blinding_optional();

	let chanmon_cfgs = create_chanmon_cfgs(6);
	let node_cfgs = create_node_cfgs(6, &chanmon_cfgs);

	*node_cfgs[1].override_init_features.borrow_mut() = Some(features);

	let node_chanmgrs = create_node_chanmgrs(
 6, &node_cfgs, &[None, Some(accept_forward_cfg), None, None, None, None]
	);
	let nodes = create_network(6, &node_cfgs, &node_chanmgrs);

	create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000_000, 1_000_000_000);
	create_unannounced_chan_between_nodes_with_value(&nodes, 2, 3, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 2, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 5, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 2, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 2, 5, 10_000_000, 1_000_000_000);

	// Add extra channels so that more than one of Bob's peers have MIN_PEER_CHANNELS and one has
	// more than the others.
	create_announced_chan_between_nodes_with_value(&nodes, 0, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 3, 4, 10_000_000, 1_000_000_000);

	let (alice, bob, charlie, david) = (&nodes[0], &nodes[1], &nodes[2], &nodes[3]);
	let bob_id = bob.node.get_our_node_id();

	disconnect_peers(alice, &[charlie, david, &nodes[4], &nodes[5]]);
	disconnect_peers(david, &[bob, &nodes[4], &nodes[5]]);

	let offer = bob.node
 .create_offer_builder().unwrap()
 .amount_msats(10_000_000)
 .build().unwrap();
	assert_ne!(offer.issuer_signing_pubkey(), Some(bob_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, nodes[4].node.get_our_node_id());
	}
}

/// Tests the dummy hop behavior of Offers based on the message router used:
/// - Compact paths (`DefaultMessageRouter`) should not include dummy hops.
/// - Node ID paths (`NodeIdMessageRouter`) may include 0 to [`MAX_DUMMY_HOPS_COUNT`] dummy hops.
Expand Down

69 changes: 33 additions & 36 deletions
lightning/src/onion_message/messenger.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -563,10 +563,6 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Logger, ES: EntropySource>
 // Limit the number of blinded paths that are computed.
 const MAX_PATHS: usize = 3;

 // Ensure peers have at least three channels so that it is more difficult to infer the
 // recipient's node_id.
 const MIN_PEER_CHANNELS: usize = 3;

 let network_graph = network_graph.deref().read_only();
 let is_recipient_announced =
 network_graph.nodes().contains_key(&NodeId::from_pubkey(&recipient));
Expand DownExpand Up@@ -596,32 +592,6 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Logger, ES: EntropySource>

 let compact_paths = !never_compact_path && size_constrained;

 let has_one_peer = peers.len() == 1;
 let mut peer_info = peers
 .map(|peer| MessageForwardNode {
 short_channel_id: if compact_paths { peer.short_channel_id } else { None },
 ..peer
 })
 // Limit to peers with announced channels unless the recipient is unannounced.
 .filter_map(|peer| {
 network_graph
 .node(&NodeId::from_pubkey(&peer.node_id))
 .filter(|info| {
 !is_recipient_announced || info.channels.len() >= MIN_PEER_CHANNELS
 })
 .map(|info| (peer, info.is_tor_only(), info.channels.len()))
 // Allow messages directly with the only peer when unannounced.
 .or_else(|| (!is_recipient_announced && has_one_peer).then(|| (peer, false, 0)))
 })
 // Exclude Tor-only nodes when the recipient is announced.
 .filter(|(_, is_tor_only, _)| !(*is_tor_only && is_recipient_announced))
 .collect::<Vec<_>>();

 // Prefer using non-Tor nodes with the most channels as the introduction node.
 peer_info.sort_unstable_by(|(_, a_tor_only, a_channels), (_, b_tor_only, b_channels)| {
 a_tor_only.cmp(b_tor_only).then(a_channels.cmp(b_channels).reverse())
 });

 let build_path = |intermediate_hops: &[MessageForwardNode]| {
 // Calculate the dummy hops given the total hop count target (including the recipient).
 let dummy_hops_count = path_len_incl_dummys.saturating_sub(intermediate_hops.len() + 1);
Expand All@@ -638,12 +608,39 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Logger, ES: EntropySource>
 )
 };

 // Try to create paths from peer info, fall back to direct path if needed
 let mut paths = peer_info
 .into_iter()
 .map(|(peer, _, _)| build_path(&[peer]))
 .take(MAX_PATHS)
 .collect::<Vec<_>>();
 let has_one_peer = peers.len() == 1;
 let mut paths = if !is_recipient_announced {
 let mut peer_info = peers
 .map(|peer| MessageForwardNode {
 short_channel_id: if compact_paths { peer.short_channel_id } else { None },
 ..peer
 })
 .filter_map(|peer| {
 network_graph
 .node(&NodeId::from_pubkey(&peer.node_id))
 .map(|info| (peer, info.is_tor_only(), info.channels.len()))
 // Allow messages directly with the only peer
 .or_else(|| has_one_peer.then(|| (peer, false, 0)))
 })
 .collect::<Vec<_>>();

 // Prefer using non-Tor nodes with the most channels as the introduction node.
 peer_info.sort_unstable_by(
 |(_, a_tor_only, a_channels), (_, b_tor_only, b_channels)| {
 a_tor_only.cmp(b_tor_only).then(a_channels.cmp(b_channels).reverse())
 },
 );

 // Try to create paths from peer info, fall back to direct path if needed
 peer_info
 .into_iter()
 .map(|(peer, _, _)| build_path(&[peer]))
 .take(MAX_PATHS)
 .collect::<Vec<_>>()
 } else {
 vec![]
 };

Comment on lines

+640
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+642

@jkczyzjkczyzJun 2, 2026

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Given we can return more than one path, couldn't we return the 1-hop path (plus dummy hops) in addition to the multi-hop paths? Senders would try all paths, or at least retry over different paths if they don't get a response over the paths requiring a direct connection with an LND node.
@TheBlueMattTheBlueMattJun 8, 2026

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The problem is the BOLT 12 offer creation stuff will pick one path at random (well, currently just the first path, but I'm not sure we want to rely on that at the messagerouter level). Doing this would indeed give us back some privacy for other usecases, but I'm not sure we care as much about hose vs BOLT 12 offers :/.

 if paths.is_empty() {
 if is_recipient_announced {
 paths = vec![build_path(&[])];
Expand Down

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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Jun 8, 2026
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Stop using an introduction node in blinded message paths
#4647
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157 changes: 2 additions & 155 deletions
lightning/src/ln/offers_tests.rs

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Original file line numberDiff line numberDiff line change
Expand Up@@ -56,7 +56,7 @@ use crate::ln::channelmanager::{PaymentId, RecentPaymentDetails, self};
use crate::ln::outbound_payment::{Bolt12PaymentError, RecipientOnionFields, Retry};
use crate::types::features::Bolt12InvoiceFeatures;
use crate::ln::functional_test_utils::*;
use crate::ln::msgs::{BaseMessageHandler, ChannelMessageHandler, Init, NodeAnnouncement, OnionMessage, OnionMessageHandler, RoutingMessageHandler, SocketAddress, UnsignedGossipMessage, UnsignedNodeAnnouncement};
use crate::ln::msgs::{BaseMessageHandler, ChannelMessageHandler, Init, OnionMessage, OnionMessageHandler};
use crate::ln::outbound_payment::IDEMPOTENCY_TIMEOUT_TICKS;
use crate::offers::invoice::Bolt12Invoice;
use crate::offers::invoice_error::InvoiceError;
Expand All@@ -66,9 +66,8 @@ use crate::offers::offer::OfferBuilder;
use crate::offers::parse::Bolt12SemanticError;
use crate::onion_message::messenger::{DefaultMessageRouter, Destination, MessageRouter, MessageSendInstructions, NodeIdMessageRouter, NullMessageRouter, PeeledOnion, DUMMY_HOPS_PATH_LENGTH, QR_CODED_DUMMY_HOPS_PATH_LENGTH};
use crate::onion_message::offers::OffersMessage;
use crate::routing::gossip::{NodeAlias, NodeId};
use crate::routing::router::{DEFAULT_PAYMENT_DUMMY_HOPS, PaymentParameters, RouteParameters, RouteParametersConfig};
use crate::sign::{NodeSigner, Recipient};
use crate::sign::NodeSigner;
use crate::util::ser::Writeable;

/// This used to determine whether we built a compact path or not, but now its just a random
Expand DownExpand Up@@ -125,38 +124,6 @@ fn disconnect_peers<'a, 'b, 'c>(node_a: &Node<'a, 'b, 'c>, peers: &[&Node<'a, 'b
	}
}

fn announce_node_address<'a, 'b, 'c>(
	node: &Node<'a, 'b, 'c>, peers: &[&Node<'a, 'b, 'c>], address: SocketAddress,
) {
	let features = node.onion_messenger.provided_node_features()
 | node.gossip_sync.provided_node_features();
	let rgb = [0u8; 3];
	let announcement = UnsignedNodeAnnouncement {
 features,
 timestamp: 1000,
 node_id: NodeId::from_pubkey(&node.keys_manager.get_node_id(Recipient::Node).unwrap()),
 rgb,
 alias: NodeAlias([0u8; 32]),
 addresses: vec![address],
 excess_address_data: Vec::new(),
 excess_data: Vec::new(),
	};
	let signature = node.keys_manager.sign_gossip_message(
 UnsignedGossipMessage::NodeAnnouncement(&announcement)
	).unwrap();

	let msg = NodeAnnouncement {
 signature,
 contents: announcement
	};

	let node_pubkey = node.node.get_our_node_id();
	node.gossip_sync.handle_node_announcement(None, &msg).unwrap();
	for peer in peers {
 peer.gossip_sync.handle_node_announcement(Some(node_pubkey), &msg).unwrap();
	}
}

fn resolve_introduction_node<'a, 'b, 'c>(node: &Node<'a, 'b, 'c>, path: &BlindedMessagePath) -> PublicKey {
	path.public_introduction_node_id(&node.network_graph.read_only())
 .and_then(|node_id| node_id.as_pubkey().ok())
Expand DownExpand Up@@ -362,126 +329,6 @@ fn create_refund_with_no_blinded_path() {
	assert!(refund.paths().is_empty());
}

/// Checks that blinded paths without Tor-only nodes are preferred when constructing an offer.
#[test]
fn prefers_non_tor_nodes_in_blinded_paths() {
	let mut accept_forward_cfg = test_default_channel_config();
	accept_forward_cfg.accept_forwards_to_priv_channels = true;

	let mut features = channelmanager::provided_init_features(&accept_forward_cfg);
	features.set_onion_messages_optional();
	features.set_route_blinding_optional();

	let chanmon_cfgs = create_chanmon_cfgs(6);
	let node_cfgs = create_node_cfgs(6, &chanmon_cfgs);

	*node_cfgs[1].override_init_features.borrow_mut() = Some(features);

	let node_chanmgrs = create_node_chanmgrs(
 6, &node_cfgs, &[None, Some(accept_forward_cfg), None, None, None, None]
	);
	let nodes = create_network(6, &node_cfgs, &node_chanmgrs);

	create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000_000, 1_000_000_000);
	create_unannounced_chan_between_nodes_with_value(&nodes, 2, 3, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 2, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 5, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 2, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 2, 5, 10_000_000, 1_000_000_000);

	// Add an extra channel so that more than one of Bob's peers have MIN_PEER_CHANNELS.
	create_announced_chan_between_nodes_with_value(&nodes, 4, 5, 10_000_000, 1_000_000_000);

	let (alice, bob, charlie, david) = (&nodes[0], &nodes[1], &nodes[2], &nodes[3]);
	let bob_id = bob.node.get_our_node_id();
	let charlie_id = charlie.node.get_our_node_id();

	disconnect_peers(alice, &[charlie, david, &nodes[4], &nodes[5]]);
	disconnect_peers(david, &[bob, &nodes[4], &nodes[5]]);

	let tor = SocketAddress::OnionV2([255, 254, 253, 252, 251, 250, 249, 248, 247, 246, 38, 7]);
	announce_node_address(charlie, &[alice, bob, david, &nodes[4], &nodes[5]], tor.clone());

	let offer = bob.node
 .create_offer_builder().unwrap()
 .amount_msats(10_000_000)
 .build().unwrap();
	assert_ne!(offer.issuer_signing_pubkey(), Some(bob_id));
	assert!(!offer.paths().is_empty());
	for path in offer.paths() {
 let introduction_node_id = resolve_introduction_node(david, &path);
 assert_ne!(introduction_node_id, bob_id);
 assert_ne!(introduction_node_id, charlie_id);
	}

	// Use a one-hop blinded path when Bob is announced and all his peers are Tor-only.
	announce_node_address(&nodes[4], &[alice, bob, charlie, david, &nodes[5]], tor.clone());
	announce_node_address(&nodes[5], &[alice, bob, charlie, david, &nodes[4]], tor.clone());

	let offer = bob.node
 .create_offer_builder().unwrap()
 .amount_msats(10_000_000)
 .build().unwrap();
	assert_ne!(offer.issuer_signing_pubkey(), Some(bob_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);
	}
}

/// Checks that blinded paths prefer an introduction node that is the most connected.
#[test]
fn prefers_more_connected_nodes_in_blinded_paths() {
	let mut accept_forward_cfg = test_default_channel_config();
	accept_forward_cfg.accept_forwards_to_priv_channels = true;

	let mut features = channelmanager::provided_init_features(&accept_forward_cfg);
	features.set_onion_messages_optional();
	features.set_route_blinding_optional();

	let chanmon_cfgs = create_chanmon_cfgs(6);
	let node_cfgs = create_node_cfgs(6, &chanmon_cfgs);

	*node_cfgs[1].override_init_features.borrow_mut() = Some(features);

	let node_chanmgrs = create_node_chanmgrs(
 6, &node_cfgs, &[None, Some(accept_forward_cfg), None, None, None, None]
	);
	let nodes = create_network(6, &node_cfgs, &node_chanmgrs);

	create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000_000, 1_000_000_000);
	create_unannounced_chan_between_nodes_with_value(&nodes, 2, 3, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 2, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 5, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 2, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 2, 5, 10_000_000, 1_000_000_000);

	// Add extra channels so that more than one of Bob's peers have MIN_PEER_CHANNELS and one has
	// more than the others.
	create_announced_chan_between_nodes_with_value(&nodes, 0, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 3, 4, 10_000_000, 1_000_000_000);

	let (alice, bob, charlie, david) = (&nodes[0], &nodes[1], &nodes[2], &nodes[3]);
	let bob_id = bob.node.get_our_node_id();

	disconnect_peers(alice, &[charlie, david, &nodes[4], &nodes[5]]);
	disconnect_peers(david, &[bob, &nodes[4], &nodes[5]]);

	let offer = bob.node
 .create_offer_builder().unwrap()
 .amount_msats(10_000_000)
 .build().unwrap();
	assert_ne!(offer.issuer_signing_pubkey(), Some(bob_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, nodes[4].node.get_our_node_id());
	}
}

/// Tests the dummy hop behavior of Offers based on the message router used:
/// - Compact paths (`DefaultMessageRouter`) should not include dummy hops.
/// - Node ID paths (`NodeIdMessageRouter`) may include 0 to [`MAX_DUMMY_HOPS_COUNT`] dummy hops.
Expand Down

69 changes: 33 additions & 36 deletions
lightning/src/onion_message/messenger.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -563,10 +563,6 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Logger, ES: EntropySource>
 // Limit the number of blinded paths that are computed.
 const MAX_PATHS: usize = 3;

 // Ensure peers have at least three channels so that it is more difficult to infer the
 // recipient's node_id.
 const MIN_PEER_CHANNELS: usize = 3;

 let network_graph = network_graph.deref().read_only();
 let is_recipient_announced =
 network_graph.nodes().contains_key(&NodeId::from_pubkey(&recipient));
Expand DownExpand Up@@ -596,32 +592,6 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Logger, ES: EntropySource>

 let compact_paths = !never_compact_path && size_constrained;

 let has_one_peer = peers.len() == 1;
 let mut peer_info = peers
 .map(|peer| MessageForwardNode {
 short_channel_id: if compact_paths { peer.short_channel_id } else { None },
 ..peer
 })
 // Limit to peers with announced channels unless the recipient is unannounced.
 .filter_map(|peer| {
 network_graph
 .node(&NodeId::from_pubkey(&peer.node_id))
 .filter(|info| {
 !is_recipient_announced || info.channels.len() >= MIN_PEER_CHANNELS
 })
 .map(|info| (peer, info.is_tor_only(), info.channels.len()))
 // Allow messages directly with the only peer when unannounced.
 .or_else(|| (!is_recipient_announced && has_one_peer).then(|| (peer, false, 0)))
 })
 // Exclude Tor-only nodes when the recipient is announced.
 .filter(|(_, is_tor_only, _)| !(*is_tor_only && is_recipient_announced))
 .collect::<Vec<_>>();

 // Prefer using non-Tor nodes with the most channels as the introduction node.
 peer_info.sort_unstable_by(|(_, a_tor_only, a_channels), (_, b_tor_only, b_channels)| {
 a_tor_only.cmp(b_tor_only).then(a_channels.cmp(b_channels).reverse())
 });

 let build_path = |intermediate_hops: &[MessageForwardNode]| {
 // Calculate the dummy hops given the total hop count target (including the recipient).
 let dummy_hops_count = path_len_incl_dummys.saturating_sub(intermediate_hops.len() + 1);
Expand All@@ -638,12 +608,39 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Logger, ES: EntropySource>
 )
 };

 // Try to create paths from peer info, fall back to direct path if needed
 let mut paths = peer_info
 .into_iter()
 .map(|(peer, _, _)| build_path(&[peer]))
 .take(MAX_PATHS)
 .collect::<Vec<_>>();
 let has_one_peer = peers.len() == 1;
 let mut paths = if !is_recipient_announced {
 let mut peer_info = peers
 .map(|peer| MessageForwardNode {
 short_channel_id: if compact_paths { peer.short_channel_id } else { None },
 ..peer
 })
 .filter_map(|peer| {
 network_graph
 .node(&NodeId::from_pubkey(&peer.node_id))
 .map(|info| (peer, info.is_tor_only(), info.channels.len()))
 // Allow messages directly with the only peer
 .or_else(|| has_one_peer.then(|| (peer, false, 0)))
 })
 .collect::<Vec<_>>();

 // Prefer using non-Tor nodes with the most channels as the introduction node.
 peer_info.sort_unstable_by(
 |(_, a_tor_only, a_channels), (_, b_tor_only, b_channels)| {
 a_tor_only.cmp(b_tor_only).then(a_channels.cmp(b_channels).reverse())
 },
 );

 // Try to create paths from peer info, fall back to direct path if needed
 peer_info
 .into_iter()
 .map(|(peer, _, _)| build_path(&[peer]))
 .take(MAX_PATHS)
 .collect::<Vec<_>>()
 } else {
 vec![]
 };

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@jkczyzjkczyzJun 2, 2026

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Given we can return more than one path, couldn't we return the 1-hop path (plus dummy hops) in addition to the multi-hop paths? Senders would try all paths, or at least retry over different paths if they don't get a response over the paths requiring a direct connection with an LND node.
@TheBlueMattTheBlueMattJun 8, 2026

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The problem is the BOLT 12 offer creation stuff will pick one path at random (well, currently just the first path, but I'm not sure we want to rely on that at the messagerouter level). Doing this would indeed give us back some privacy for other usecases, but I'm not sure we care as much about hose vs BOLT 12 offers :/.

 if paths.is_empty() {
 if is_recipient_announced {
 paths = vec![build_path(&[])];
Expand Down

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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Stop using an introduction node in blinded message paths#4647

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jkczyz
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Jun 8, 2026
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Stop using an introduction node in blinded message paths
#4647
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157 changes: 2 additions & 155 deletions
lightning/src/ln/offers_tests.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -56,7 +56,7 @@ use crate::ln::channelmanager::{PaymentId, RecentPaymentDetails, self};
use crate::ln::outbound_payment::{Bolt12PaymentError, RecipientOnionFields, Retry};
use crate::types::features::Bolt12InvoiceFeatures;
use crate::ln::functional_test_utils::*;
use crate::ln::msgs::{BaseMessageHandler, ChannelMessageHandler, Init, NodeAnnouncement, OnionMessage, OnionMessageHandler, RoutingMessageHandler, SocketAddress, UnsignedGossipMessage, UnsignedNodeAnnouncement};
use crate::ln::msgs::{BaseMessageHandler, ChannelMessageHandler, Init, OnionMessage, OnionMessageHandler};
use crate::ln::outbound_payment::IDEMPOTENCY_TIMEOUT_TICKS;
use crate::offers::invoice::Bolt12Invoice;
use crate::offers::invoice_error::InvoiceError;
Expand All@@ -66,9 +66,8 @@ use crate::offers::offer::OfferBuilder;
use crate::offers::parse::Bolt12SemanticError;
use crate::onion_message::messenger::{DefaultMessageRouter, Destination, MessageRouter, MessageSendInstructions, NodeIdMessageRouter, NullMessageRouter, PeeledOnion, DUMMY_HOPS_PATH_LENGTH, QR_CODED_DUMMY_HOPS_PATH_LENGTH};
use crate::onion_message::offers::OffersMessage;
use crate::routing::gossip::{NodeAlias, NodeId};
use crate::routing::router::{DEFAULT_PAYMENT_DUMMY_HOPS, PaymentParameters, RouteParameters, RouteParametersConfig};
use crate::sign::{NodeSigner, Recipient};
use crate::sign::NodeSigner;
use crate::util::ser::Writeable;

/// This used to determine whether we built a compact path or not, but now its just a random
Expand DownExpand Up@@ -125,38 +124,6 @@ fn disconnect_peers<'a, 'b, 'c>(node_a: &Node<'a, 'b, 'c>, peers: &[&Node<'a, 'b
	}
}

fn announce_node_address<'a, 'b, 'c>(
	node: &Node<'a, 'b, 'c>, peers: &[&Node<'a, 'b, 'c>], address: SocketAddress,
) {
	let features = node.onion_messenger.provided_node_features()
 | node.gossip_sync.provided_node_features();
	let rgb = [0u8; 3];
	let announcement = UnsignedNodeAnnouncement {
 features,
 timestamp: 1000,
 node_id: NodeId::from_pubkey(&node.keys_manager.get_node_id(Recipient::Node).unwrap()),
 rgb,
 alias: NodeAlias([0u8; 32]),
 addresses: vec![address],
 excess_address_data: Vec::new(),
 excess_data: Vec::new(),
	};
	let signature = node.keys_manager.sign_gossip_message(
 UnsignedGossipMessage::NodeAnnouncement(&announcement)
	).unwrap();

	let msg = NodeAnnouncement {
 signature,
 contents: announcement
	};

	let node_pubkey = node.node.get_our_node_id();
	node.gossip_sync.handle_node_announcement(None, &msg).unwrap();
	for peer in peers {
 peer.gossip_sync.handle_node_announcement(Some(node_pubkey), &msg).unwrap();
	}
}

fn resolve_introduction_node<'a, 'b, 'c>(node: &Node<'a, 'b, 'c>, path: &BlindedMessagePath) -> PublicKey {
	path.public_introduction_node_id(&node.network_graph.read_only())
 .and_then(|node_id| node_id.as_pubkey().ok())
Expand DownExpand Up@@ -362,126 +329,6 @@ fn create_refund_with_no_blinded_path() {
	assert!(refund.paths().is_empty());
}

/// Checks that blinded paths without Tor-only nodes are preferred when constructing an offer.
#[test]
fn prefers_non_tor_nodes_in_blinded_paths() {
	let mut accept_forward_cfg = test_default_channel_config();
	accept_forward_cfg.accept_forwards_to_priv_channels = true;

	let mut features = channelmanager::provided_init_features(&accept_forward_cfg);
	features.set_onion_messages_optional();
	features.set_route_blinding_optional();

	let chanmon_cfgs = create_chanmon_cfgs(6);
	let node_cfgs = create_node_cfgs(6, &chanmon_cfgs);

	*node_cfgs[1].override_init_features.borrow_mut() = Some(features);

	let node_chanmgrs = create_node_chanmgrs(
 6, &node_cfgs, &[None, Some(accept_forward_cfg), None, None, None, None]
	);
	let nodes = create_network(6, &node_cfgs, &node_chanmgrs);

	create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000_000, 1_000_000_000);
	create_unannounced_chan_between_nodes_with_value(&nodes, 2, 3, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 2, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 5, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 2, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 2, 5, 10_000_000, 1_000_000_000);

	// Add an extra channel so that more than one of Bob's peers have MIN_PEER_CHANNELS.
	create_announced_chan_between_nodes_with_value(&nodes, 4, 5, 10_000_000, 1_000_000_000);

	let (alice, bob, charlie, david) = (&nodes[0], &nodes[1], &nodes[2], &nodes[3]);
	let bob_id = bob.node.get_our_node_id();
	let charlie_id = charlie.node.get_our_node_id();

	disconnect_peers(alice, &[charlie, david, &nodes[4], &nodes[5]]);
	disconnect_peers(david, &[bob, &nodes[4], &nodes[5]]);

	let tor = SocketAddress::OnionV2([255, 254, 253, 252, 251, 250, 249, 248, 247, 246, 38, 7]);
	announce_node_address(charlie, &[alice, bob, david, &nodes[4], &nodes[5]], tor.clone());

	let offer = bob.node
 .create_offer_builder().unwrap()
 .amount_msats(10_000_000)
 .build().unwrap();
	assert_ne!(offer.issuer_signing_pubkey(), Some(bob_id));
	assert!(!offer.paths().is_empty());
	for path in offer.paths() {
 let introduction_node_id = resolve_introduction_node(david, &path);
 assert_ne!(introduction_node_id, bob_id);
 assert_ne!(introduction_node_id, charlie_id);
	}

	// Use a one-hop blinded path when Bob is announced and all his peers are Tor-only.
	announce_node_address(&nodes[4], &[alice, bob, charlie, david, &nodes[5]], tor.clone());
	announce_node_address(&nodes[5], &[alice, bob, charlie, david, &nodes[4]], tor.clone());

	let offer = bob.node
 .create_offer_builder().unwrap()
 .amount_msats(10_000_000)
 .build().unwrap();
	assert_ne!(offer.issuer_signing_pubkey(), Some(bob_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);
	}
}

/// Checks that blinded paths prefer an introduction node that is the most connected.
#[test]
fn prefers_more_connected_nodes_in_blinded_paths() {
	let mut accept_forward_cfg = test_default_channel_config();
	accept_forward_cfg.accept_forwards_to_priv_channels = true;

	let mut features = channelmanager::provided_init_features(&accept_forward_cfg);
	features.set_onion_messages_optional();
	features.set_route_blinding_optional();

	let chanmon_cfgs = create_chanmon_cfgs(6);
	let node_cfgs = create_node_cfgs(6, &chanmon_cfgs);

	*node_cfgs[1].override_init_features.borrow_mut() = Some(features);

	let node_chanmgrs = create_node_chanmgrs(
 6, &node_cfgs, &[None, Some(accept_forward_cfg), None, None, None, None]
	);
	let nodes = create_network(6, &node_cfgs, &node_chanmgrs);

	create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000_000, 1_000_000_000);
	create_unannounced_chan_between_nodes_with_value(&nodes, 2, 3, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 2, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 5, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 2, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 2, 5, 10_000_000, 1_000_000_000);

	// Add extra channels so that more than one of Bob's peers have MIN_PEER_CHANNELS and one has
	// more than the others.
	create_announced_chan_between_nodes_with_value(&nodes, 0, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 3, 4, 10_000_000, 1_000_000_000);

	let (alice, bob, charlie, david) = (&nodes[0], &nodes[1], &nodes[2], &nodes[3]);
	let bob_id = bob.node.get_our_node_id();

	disconnect_peers(alice, &[charlie, david, &nodes[4], &nodes[5]]);
	disconnect_peers(david, &[bob, &nodes[4], &nodes[5]]);

	let offer = bob.node
 .create_offer_builder().unwrap()
 .amount_msats(10_000_000)
 .build().unwrap();
	assert_ne!(offer.issuer_signing_pubkey(), Some(bob_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, nodes[4].node.get_our_node_id());
	}
}

/// Tests the dummy hop behavior of Offers based on the message router used:
/// - Compact paths (`DefaultMessageRouter`) should not include dummy hops.
/// - Node ID paths (`NodeIdMessageRouter`) may include 0 to [`MAX_DUMMY_HOPS_COUNT`] dummy hops.
Expand Down

69 changes: 33 additions & 36 deletions
lightning/src/onion_message/messenger.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -563,10 +563,6 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Logger, ES: EntropySource>
 // Limit the number of blinded paths that are computed.
 const MAX_PATHS: usize = 3;

 // Ensure peers have at least three channels so that it is more difficult to infer the
 // recipient's node_id.
 const MIN_PEER_CHANNELS: usize = 3;

 let network_graph = network_graph.deref().read_only();
 let is_recipient_announced =
 network_graph.nodes().contains_key(&NodeId::from_pubkey(&recipient));
Expand DownExpand Up@@ -596,32 +592,6 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Logger, ES: EntropySource>

 let compact_paths = !never_compact_path && size_constrained;

 let has_one_peer = peers.len() == 1;
 let mut peer_info = peers
 .map(|peer| MessageForwardNode {
 short_channel_id: if compact_paths { peer.short_channel_id } else { None },
 ..peer
 })
 // Limit to peers with announced channels unless the recipient is unannounced.
 .filter_map(|peer| {
 network_graph
 .node(&NodeId::from_pubkey(&peer.node_id))
 .filter(|info| {
 !is_recipient_announced || info.channels.len() >= MIN_PEER_CHANNELS
 })
 .map(|info| (peer, info.is_tor_only(), info.channels.len()))
 // Allow messages directly with the only peer when unannounced.
 .or_else(|| (!is_recipient_announced && has_one_peer).then(|| (peer, false, 0)))
 })
 // Exclude Tor-only nodes when the recipient is announced.
 .filter(|(_, is_tor_only, _)| !(*is_tor_only && is_recipient_announced))
 .collect::<Vec<_>>();

 // Prefer using non-Tor nodes with the most channels as the introduction node.
 peer_info.sort_unstable_by(|(_, a_tor_only, a_channels), (_, b_tor_only, b_channels)| {
 a_tor_only.cmp(b_tor_only).then(a_channels.cmp(b_channels).reverse())
 });

 let build_path = |intermediate_hops: &[MessageForwardNode]| {
 // Calculate the dummy hops given the total hop count target (including the recipient).
 let dummy_hops_count = path_len_incl_dummys.saturating_sub(intermediate_hops.len() + 1);
Expand All@@ -638,12 +608,39 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Logger, ES: EntropySource>
 )
 };

 // Try to create paths from peer info, fall back to direct path if needed
 let mut paths = peer_info
 .into_iter()
 .map(|(peer, _, _)| build_path(&[peer]))
 .take(MAX_PATHS)
 .collect::<Vec<_>>();
 let has_one_peer = peers.len() == 1;
 let mut paths = if !is_recipient_announced {
 let mut peer_info = peers
 .map(|peer| MessageForwardNode {
 short_channel_id: if compact_paths { peer.short_channel_id } else { None },
 ..peer
 })
 .filter_map(|peer| {
 network_graph
 .node(&NodeId::from_pubkey(&peer.node_id))
 .map(|info| (peer, info.is_tor_only(), info.channels.len()))
 // Allow messages directly with the only peer
 .or_else(|| has_one_peer.then(|| (peer, false, 0)))
 })
 .collect::<Vec<_>>();

 // Prefer using non-Tor nodes with the most channels as the introduction node.
 peer_info.sort_unstable_by(
 |(_, a_tor_only, a_channels), (_, b_tor_only, b_channels)| {
 a_tor_only.cmp(b_tor_only).then(a_channels.cmp(b_channels).reverse())
 },
 );

 // Try to create paths from peer info, fall back to direct path if needed
 peer_info
 .into_iter()
 .map(|(peer, _, _)| build_path(&[peer]))
 .take(MAX_PATHS)
 .collect::<Vec<_>>()
 } else {
 vec![]
 };

Comment on lines

+640
 to 
+642

@jkczyzjkczyzJun 2, 2026

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Given we can return more than one path, couldn't we return the 1-hop path (plus dummy hops) in addition to the multi-hop paths? Senders would try all paths, or at least retry over different paths if they don't get a response over the paths requiring a direct connection with an LND node.
@TheBlueMattTheBlueMattJun 8, 2026

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The problem is the BOLT 12 offer creation stuff will pick one path at random (well, currently just the first path, but I'm not sure we want to rely on that at the messagerouter level). Doing this would indeed give us back some privacy for other usecases, but I'm not sure we care as much about hose vs BOLT 12 offers :/.

 if paths.is_empty() {
 if is_recipient_announced {
 paths = vec![build_path(&[])];
Expand Down

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

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Stop using an introduction node in blinded message paths#4647

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 Merged

jkczyz
merged 1 commit into

from

Jun 8, 2026
 Merged


Stop using an introduction node in blinded message paths
#4647
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157 changes: 2 additions & 155 deletions
lightning/src/ln/offers_tests.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -56,7 +56,7 @@ use crate::ln::channelmanager::{PaymentId, RecentPaymentDetails, self};
use crate::ln::outbound_payment::{Bolt12PaymentError, RecipientOnionFields, Retry};
use crate::types::features::Bolt12InvoiceFeatures;
use crate::ln::functional_test_utils::*;
use crate::ln::msgs::{BaseMessageHandler, ChannelMessageHandler, Init, NodeAnnouncement, OnionMessage, OnionMessageHandler, RoutingMessageHandler, SocketAddress, UnsignedGossipMessage, UnsignedNodeAnnouncement};
use crate::ln::msgs::{BaseMessageHandler, ChannelMessageHandler, Init, OnionMessage, OnionMessageHandler};
use crate::ln::outbound_payment::IDEMPOTENCY_TIMEOUT_TICKS;
use crate::offers::invoice::Bolt12Invoice;
use crate::offers::invoice_error::InvoiceError;
Expand All@@ -66,9 +66,8 @@ use crate::offers::offer::OfferBuilder;
use crate::offers::parse::Bolt12SemanticError;
use crate::onion_message::messenger::{DefaultMessageRouter, Destination, MessageRouter, MessageSendInstructions, NodeIdMessageRouter, NullMessageRouter, PeeledOnion, DUMMY_HOPS_PATH_LENGTH, QR_CODED_DUMMY_HOPS_PATH_LENGTH};
use crate::onion_message::offers::OffersMessage;
use crate::routing::gossip::{NodeAlias, NodeId};
use crate::routing::router::{DEFAULT_PAYMENT_DUMMY_HOPS, PaymentParameters, RouteParameters, RouteParametersConfig};
use crate::sign::{NodeSigner, Recipient};
use crate::sign::NodeSigner;
use crate::util::ser::Writeable;

/// This used to determine whether we built a compact path or not, but now its just a random
Expand DownExpand Up@@ -125,38 +124,6 @@ fn disconnect_peers<'a, 'b, 'c>(node_a: &Node<'a, 'b, 'c>, peers: &[&Node<'a, 'b
	}
}

fn announce_node_address<'a, 'b, 'c>(
	node: &Node<'a, 'b, 'c>, peers: &[&Node<'a, 'b, 'c>], address: SocketAddress,
) {
	let features = node.onion_messenger.provided_node_features()
 | node.gossip_sync.provided_node_features();
	let rgb = [0u8; 3];
	let announcement = UnsignedNodeAnnouncement {
 features,
 timestamp: 1000,
 node_id: NodeId::from_pubkey(&node.keys_manager.get_node_id(Recipient::Node).unwrap()),
 rgb,
 alias: NodeAlias([0u8; 32]),
 addresses: vec![address],
 excess_address_data: Vec::new(),
 excess_data: Vec::new(),
	};
	let signature = node.keys_manager.sign_gossip_message(
 UnsignedGossipMessage::NodeAnnouncement(&announcement)
	).unwrap();

	let msg = NodeAnnouncement {
 signature,
 contents: announcement
	};

	let node_pubkey = node.node.get_our_node_id();
	node.gossip_sync.handle_node_announcement(None, &msg).unwrap();
	for peer in peers {
 peer.gossip_sync.handle_node_announcement(Some(node_pubkey), &msg).unwrap();
	}
}

fn resolve_introduction_node<'a, 'b, 'c>(node: &Node<'a, 'b, 'c>, path: &BlindedMessagePath) -> PublicKey {
	path.public_introduction_node_id(&node.network_graph.read_only())
 .and_then(|node_id| node_id.as_pubkey().ok())
Expand DownExpand Up@@ -362,126 +329,6 @@ fn create_refund_with_no_blinded_path() {
	assert!(refund.paths().is_empty());
}

/// Checks that blinded paths without Tor-only nodes are preferred when constructing an offer.
#[test]
fn prefers_non_tor_nodes_in_blinded_paths() {
	let mut accept_forward_cfg = test_default_channel_config();
	accept_forward_cfg.accept_forwards_to_priv_channels = true;

	let mut features = channelmanager::provided_init_features(&accept_forward_cfg);
	features.set_onion_messages_optional();
	features.set_route_blinding_optional();

	let chanmon_cfgs = create_chanmon_cfgs(6);
	let node_cfgs = create_node_cfgs(6, &chanmon_cfgs);

	*node_cfgs[1].override_init_features.borrow_mut() = Some(features);

	let node_chanmgrs = create_node_chanmgrs(
 6, &node_cfgs, &[None, Some(accept_forward_cfg), None, None, None, None]
	);
	let nodes = create_network(6, &node_cfgs, &node_chanmgrs);

	create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000_000, 1_000_000_000);
	create_unannounced_chan_between_nodes_with_value(&nodes, 2, 3, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 2, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 5, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 2, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 2, 5, 10_000_000, 1_000_000_000);

	// Add an extra channel so that more than one of Bob's peers have MIN_PEER_CHANNELS.
	create_announced_chan_between_nodes_with_value(&nodes, 4, 5, 10_000_000, 1_000_000_000);

	let (alice, bob, charlie, david) = (&nodes[0], &nodes[1], &nodes[2], &nodes[3]);
	let bob_id = bob.node.get_our_node_id();
	let charlie_id = charlie.node.get_our_node_id();

	disconnect_peers(alice, &[charlie, david, &nodes[4], &nodes[5]]);
	disconnect_peers(david, &[bob, &nodes[4], &nodes[5]]);

	let tor = SocketAddress::OnionV2([255, 254, 253, 252, 251, 250, 249, 248, 247, 246, 38, 7]);
	announce_node_address(charlie, &[alice, bob, david, &nodes[4], &nodes[5]], tor.clone());

	let offer = bob.node
 .create_offer_builder().unwrap()
 .amount_msats(10_000_000)
 .build().unwrap();
	assert_ne!(offer.issuer_signing_pubkey(), Some(bob_id));
	assert!(!offer.paths().is_empty());
	for path in offer.paths() {
 let introduction_node_id = resolve_introduction_node(david, &path);
 assert_ne!(introduction_node_id, bob_id);
 assert_ne!(introduction_node_id, charlie_id);
	}

	// Use a one-hop blinded path when Bob is announced and all his peers are Tor-only.
	announce_node_address(&nodes[4], &[alice, bob, charlie, david, &nodes[5]], tor.clone());
	announce_node_address(&nodes[5], &[alice, bob, charlie, david, &nodes[4]], tor.clone());

	let offer = bob.node
 .create_offer_builder().unwrap()
 .amount_msats(10_000_000)
 .build().unwrap();
	assert_ne!(offer.issuer_signing_pubkey(), Some(bob_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);
	}
}

/// Checks that blinded paths prefer an introduction node that is the most connected.
#[test]
fn prefers_more_connected_nodes_in_blinded_paths() {
	let mut accept_forward_cfg = test_default_channel_config();
	accept_forward_cfg.accept_forwards_to_priv_channels = true;

	let mut features = channelmanager::provided_init_features(&accept_forward_cfg);
	features.set_onion_messages_optional();
	features.set_route_blinding_optional();

	let chanmon_cfgs = create_chanmon_cfgs(6);
	let node_cfgs = create_node_cfgs(6, &chanmon_cfgs);

	*node_cfgs[1].override_init_features.borrow_mut() = Some(features);

	let node_chanmgrs = create_node_chanmgrs(
 6, &node_cfgs, &[None, Some(accept_forward_cfg), None, None, None, None]
	);
	let nodes = create_network(6, &node_cfgs, &node_chanmgrs);

	create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000_000, 1_000_000_000);
	create_unannounced_chan_between_nodes_with_value(&nodes, 2, 3, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 2, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 1, 5, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 2, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 2, 5, 10_000_000, 1_000_000_000);

	// Add extra channels so that more than one of Bob's peers have MIN_PEER_CHANNELS and one has
	// more than the others.
	create_announced_chan_between_nodes_with_value(&nodes, 0, 4, 10_000_000, 1_000_000_000);
	create_announced_chan_between_nodes_with_value(&nodes, 3, 4, 10_000_000, 1_000_000_000);

	let (alice, bob, charlie, david) = (&nodes[0], &nodes[1], &nodes[2], &nodes[3]);
	let bob_id = bob.node.get_our_node_id();

	disconnect_peers(alice, &[charlie, david, &nodes[4], &nodes[5]]);
	disconnect_peers(david, &[bob, &nodes[4], &nodes[5]]);

	let offer = bob.node
 .create_offer_builder().unwrap()
 .amount_msats(10_000_000)
 .build().unwrap();
	assert_ne!(offer.issuer_signing_pubkey(), Some(bob_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, nodes[4].node.get_our_node_id());
	}
}

/// Tests the dummy hop behavior of Offers based on the message router used:
/// - Compact paths (`DefaultMessageRouter`) should not include dummy hops.
/// - Node ID paths (`NodeIdMessageRouter`) may include 0 to [`MAX_DUMMY_HOPS_COUNT`] dummy hops.
Expand Down

69 changes: 33 additions & 36 deletions
lightning/src/onion_message/messenger.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -563,10 +563,6 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Logger, ES: EntropySource>
 // Limit the number of blinded paths that are computed.
 const MAX_PATHS: usize = 3;

 // Ensure peers have at least three channels so that it is more difficult to infer the
 // recipient's node_id.
 const MIN_PEER_CHANNELS: usize = 3;

 let network_graph = network_graph.deref().read_only();
 let is_recipient_announced =
 network_graph.nodes().contains_key(&NodeId::from_pubkey(&recipient));
Expand DownExpand Up@@ -596,32 +592,6 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Logger, ES: EntropySource>

 let compact_paths = !never_compact_path && size_constrained;

 let has_one_peer = peers.len() == 1;
 let mut peer_info = peers
 .map(|peer| MessageForwardNode {
 short_channel_id: if compact_paths { peer.short_channel_id } else { None },
 ..peer
 })
 // Limit to peers with announced channels unless the recipient is unannounced.
 .filter_map(|peer| {
 network_graph
 .node(&NodeId::from_pubkey(&peer.node_id))
 .filter(|info| {
 !is_recipient_announced || info.channels.len() >= MIN_PEER_CHANNELS
 })
 .map(|info| (peer, info.is_tor_only(), info.channels.len()))
 // Allow messages directly with the only peer when unannounced.
 .or_else(|| (!is_recipient_announced && has_one_peer).then(|| (peer, false, 0)))
 })
 // Exclude Tor-only nodes when the recipient is announced.
 .filter(|(_, is_tor_only, _)| !(*is_tor_only && is_recipient_announced))
 .collect::<Vec<_>>();

 // Prefer using non-Tor nodes with the most channels as the introduction node.
 peer_info.sort_unstable_by(|(_, a_tor_only, a_channels), (_, b_tor_only, b_channels)| {
 a_tor_only.cmp(b_tor_only).then(a_channels.cmp(b_channels).reverse())
 });

 let build_path = |intermediate_hops: &[MessageForwardNode]| {
 // Calculate the dummy hops given the total hop count target (including the recipient).
 let dummy_hops_count = path_len_incl_dummys.saturating_sub(intermediate_hops.len() + 1);
Expand All@@ -638,12 +608,39 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Logger, ES: EntropySource>
 )
 };

 // Try to create paths from peer info, fall back to direct path if needed
 let mut paths = peer_info
 .into_iter()
 .map(|(peer, _, _)| build_path(&[peer]))
 .take(MAX_PATHS)
 .collect::<Vec<_>>();
 let has_one_peer = peers.len() == 1;
 let mut paths = if !is_recipient_announced {
 let mut peer_info = peers
 .map(|peer| MessageForwardNode {
 short_channel_id: if compact_paths { peer.short_channel_id } else { None },
 ..peer
 })
 .filter_map(|peer| {
 network_graph
 .node(&NodeId::from_pubkey(&peer.node_id))
 .map(|info| (peer, info.is_tor_only(), info.channels.len()))
 // Allow messages directly with the only peer
 .or_else(|| has_one_peer.then(|| (peer, false, 0)))
 })
 .collect::<Vec<_>>();

 // Prefer using non-Tor nodes with the most channels as the introduction node.
 peer_info.sort_unstable_by(
 |(_, a_tor_only, a_channels), (_, b_tor_only, b_channels)| {
 a_tor_only.cmp(b_tor_only).then(a_channels.cmp(b_channels).reverse())
 },
 );

 // Try to create paths from peer info, fall back to direct path if needed
 peer_info
 .into_iter()
 .map(|(peer, _, _)| build_path(&[peer]))
 .take(MAX_PATHS)
 .collect::<Vec<_>>()
 } else {
 vec![]
 };

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@jkczyzjkczyzJun 2, 2026

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Given we can return more than one path, couldn't we return the 1-hop path (plus dummy hops) in addition to the multi-hop paths? Senders would try all paths, or at least retry over different paths if they don't get a response over the paths requiring a direct connection with an LND node.
@TheBlueMattTheBlueMattJun 8, 2026

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The problem is the BOLT 12 offer creation stuff will pick one path at random (well, currently just the first path, but I'm not sure we want to rely on that at the messagerouter level). Doing this would indeed give us back some privacy for other usecases, but I'm not sure we care as much about hose vs BOLT 12 offers :/.

 if paths.is_empty() {
 if is_recipient_announced {
 paths = vec![build_path(&[])];
Expand Down