pass_along_path(&nodes[0], &path, 10000, payment_hash, None, event, true, Some(test_preimage));
claim_payment(&nodes[0], &path, test_preimage);
}
+
+fn do_test_max_dust_htlc_exposure(dust_outbound_balance: bool, at_forward: bool, on_holder_tx: bool) {
+ // Test that we properly reject dust HTLC violating our `max_dust_htlc_exposure_msat`
+ // policy.
+ //
+ // At HTLC forward (`send_payment()`), if the sum of the trimmed-to-dust HTLC inbound and
+ // trimmed-to-dust HTLC outbound balance and this new payment as included on next
+ // counterparty commitment are above our `max_dust_htlc_exposure_msat`, we'll reject the
+ // update. At HTLC reception (`update_add_htlc()`), if the sum of the trimmed-to-dust HTLC
+ // inbound and trimmed-to-dust HTLC outbound balance and this new received HTLC as included
+ // on next counterparty commitment are above our `max_dust_htlc_exposure_msat`, we'll fail
+ // the update. Note, we return a `temporary_channel_failure` (0x1000 | 7), as the channel
+ // might be available again for HTLC processing once the dust bandwidth has cleared up.
+
+ let chanmon_cfgs = create_chanmon_cfgs(2);
+ let mut config = test_default_channel_config();
+ config.channel_options.max_dust_htlc_exposure_msat = 5_000_000; // default setting value
+ let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
+ let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, Some(config)]);
+ let mut nodes = create_network(2, &node_cfgs, &node_chanmgrs);
+
+ nodes[0].node.create_channel(nodes[1].node.get_our_node_id(), 1_000_000, 500_000_000, 42, None).unwrap();
+ let mut open_channel = get_event_msg!(nodes[0], MessageSendEvent::SendOpenChannel, nodes[1].node.get_our_node_id());
+ open_channel.max_htlc_value_in_flight_msat = 50_000_000;
+ open_channel.max_accepted_htlcs = 60;
+ nodes[1].node.handle_open_channel(&nodes[0].node.get_our_node_id(), InitFeatures::known(), &open_channel);
+ let mut accept_channel = get_event_msg!(nodes[1], MessageSendEvent::SendAcceptChannel, nodes[0].node.get_our_node_id());
+ if on_holder_tx {
+ accept_channel.dust_limit_satoshis = 546;
+ }
+ nodes[0].node.handle_accept_channel(&nodes[1].node.get_our_node_id(), InitFeatures::known(), &accept_channel);
+
+ let (temporary_channel_id, tx, _) = create_funding_transaction(&nodes[0], 1_000_000, 42);
+
+ if on_holder_tx {
+ if let Some(mut chan) = nodes[1].node.channel_state.lock().unwrap().by_id.get_mut(&temporary_channel_id) {
+ chan.holder_dust_limit_satoshis = 546;
+ }
+ }
+
+ nodes[0].node.funding_transaction_generated(&temporary_channel_id, tx.clone()).unwrap();
+ nodes[1].node.handle_funding_created(&nodes[0].node.get_our_node_id(), &get_event_msg!(nodes[0], MessageSendEvent::SendFundingCreated, nodes[1].node.get_our_node_id()));
+ check_added_monitors!(nodes[1], 1);
+
+ nodes[0].node.handle_funding_signed(&nodes[1].node.get_our_node_id(), &get_event_msg!(nodes[1], MessageSendEvent::SendFundingSigned, nodes[0].node.get_our_node_id()));
+ check_added_monitors!(nodes[0], 1);
+
+ let (funding_locked, _) = create_chan_between_nodes_with_value_confirm(&nodes[0], &nodes[1], &tx);
+ let (announcement, as_update, bs_update) = create_chan_between_nodes_with_value_b(&nodes[0], &nodes[1], &funding_locked);
+ update_nodes_with_chan_announce(&nodes, 0, 1, &announcement, &as_update, &bs_update);
+
+ if on_holder_tx {
+ if dust_outbound_balance {
+ // Outbound dust threshold: 2223 sats (`dust_buffer_feerate` * HTLC_TIMEOUT_TX_WEIGHT / 1000 + holder's `dust_limit_satoshis`)
+ // Outbound dust balance: 4372 sats
+ // Note, we need sent payment to be above outbound dust threshold on counterparty_tx of 2132 sats
+ for i in 0..2 {
+ let (route, payment_hash, _, payment_secret) = get_route_and_payment_hash!(nodes[1], nodes[0], 2_186_000);
+ if let Err(_) = nodes[1].node.send_payment(&route, payment_hash, &Some(payment_secret)) { panic!("Unexpected event at dust HTLC {}", i); }
+ }
+ } else {
+ // Inbound dust threshold: 2324 sats (`dust_buffer_feerate` * HTLC_SUCCESS_TX_WEIGHT / 1000 + holder's `dust_limit_satoshis`)
+ // Inbound dust balance: 4372 sats
+ // Note, we need sent payment to be above outbound dust threshold on counterparty_tx of 2031 sats
+ for _ in 0..2 {
+ route_payment(&nodes[0], &[&nodes[1]], 2_186_000);
+ }
+ }
+ } else {
+ if dust_outbound_balance {
+ // Outbound dust threshold: 2132 sats (`dust_buffer_feerate` * HTLC_TIMEOUT_TX_WEIGHT / 1000 + counteparty's `dust_limit_satoshis`)
+ // Outbound dust balance: 5000 sats
+ for i in 0..25 {
+ let (route, payment_hash, _, payment_secret) = get_route_and_payment_hash!(nodes[1], nodes[0], 200_000);
+ if let Err(_) = nodes[1].node.send_payment(&route, payment_hash, &Some(payment_secret)) { panic!("Unexpected event at dust HTLC {}", i); }
+ }
+ } else {
+ // Inbound dust threshold: 2031 sats (`dust_buffer_feerate` * HTLC_TIMEOUT_TX_WEIGHT / 1000 + counteparty's `dust_limit_satoshis`)
+ // Inbound dust balance: 5000 sats
+ for _ in 0..25 {
+ route_payment(&nodes[0], &[&nodes[1]], 200_000);
+ }
+ }
+ }
+
+ if at_forward {
+ let (route, payment_hash, _, payment_secret) = get_route_and_payment_hash!(nodes[1], nodes[0], if on_holder_tx { 2_186_000 } else { 200_000 });
+ let mut config = UserConfig::default();
+ // With default dust exposure: 5000 sats
+ if on_holder_tx {
+ // Outbound dust balance: 6558 sats
+ unwrap_send_err!(nodes[1].node.send_payment(&route, payment_hash, &Some(payment_secret)), true, APIError::ChannelUnavailable { ref err }, assert_eq!(err, &format!("Cannot send value that would put our exposure to dust HTLCs at {} over the limit {} on holder commitment tx", 6_558_000, config.channel_options.max_dust_htlc_exposure_msat)));
+ } else {
+ // Outbound dust balance: 5200 sats
+ unwrap_send_err!(nodes[1].node.send_payment(&route, payment_hash, &Some(payment_secret)), true, APIError::ChannelUnavailable { ref err }, assert_eq!(err, &format!("Cannot send value that would put our exposure to dust HTLCs at {} over the limit {} on counterparty commitment tx", 5_200_000, config.channel_options.max_dust_htlc_exposure_msat)));
+ }
+ } else {
+ let (route, payment_hash, _, payment_secret) = get_route_and_payment_hash!(nodes[0], nodes[1 ], if on_holder_tx { 2_186_000 } else { 200_000 });
+ nodes[0].node.send_payment(&route, payment_hash, &Some(payment_secret)).unwrap();
+ check_added_monitors!(nodes[0], 1);
+ let mut events = nodes[0].node.get_and_clear_pending_msg_events();
+ assert_eq!(events.len(), 1);
+ let payment_event = SendEvent::from_event(events.remove(0));
+ nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &payment_event.msgs[0]);
+ // With default dust exposure: 5000 sats
+ if on_holder_tx {
+ // Outbound dust balance: 6558 sats
+ nodes[1].logger.assert_log("lightning::ln::channel".to_string(), format!("Cannot accept value that would put our exposure to dust HTLCs at {} over the limit {} on holder commitment tx", 6_558_000, config.channel_options.max_dust_htlc_exposure_msat), 1);
+ } else {
+ // Outbound dust balance: 5200 sats
+ nodes[1].logger.assert_log("lightning::ln::channel".to_string(), format!("Cannot accept value that would put our exposure to dust HTLCs at {} over the limit {} on counterparty commitment tx", 5_200_000, config.channel_options.max_dust_htlc_exposure_msat), 1);
+ }
+ }
+
+ let _ = nodes[1].node.get_and_clear_pending_msg_events();
+ let mut added_monitors = nodes[1].chain_monitor.added_monitors.lock().unwrap();
+ added_monitors.clear();
+}
+
+#[test]
+fn test_max_dust_htlc_exposure() {
+ do_test_max_dust_htlc_exposure(true, true, true);
+ do_test_max_dust_htlc_exposure(false, true, true);
+ do_test_max_dust_htlc_exposure(false, false, true);
+ do_test_max_dust_htlc_exposure(false, false, false);
+ do_test_max_dust_htlc_exposure(true, true, false);
+ do_test_max_dust_htlc_exposure(true, false, false);
+ do_test_max_dust_htlc_exposure(true, false, true);
+ do_test_max_dust_htlc_exposure(false, true, false);
+}