+ pub(crate) fn get_and_clear_pending_claim_events(&mut self) -> Vec<(ClaimId, ClaimEvent)> {
+ let mut events = Vec::new();
+ swap(&mut events, &mut self.pending_claim_events);
+ events
+ }
+
+ /// Triggers rebroadcasts/fee-bumps of pending claims from a force-closed channel. This is
+ /// crucial in preventing certain classes of pinning attacks, detecting substantial mempool
+ /// feerate changes between blocks, and ensuring reliability if broadcasting fails. We recommend
+ /// invoking this every 30 seconds, or lower if running in an environment with spotty
+ /// connections, like on mobile.
+ pub(super) fn rebroadcast_pending_claims<B: Deref, F: Deref, L: Logger>(
+ &mut self, current_height: u32, feerate_strategy: FeerateStrategy, broadcaster: &B,
+ fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L,
+ )
+ where
+ B::Target: BroadcasterInterface,
+ F::Target: FeeEstimator,
+ {
+ let mut bump_requests = Vec::with_capacity(self.pending_claim_requests.len());
+ for (claim_id, request) in self.pending_claim_requests.iter() {
+ let inputs = request.outpoints();
+ log_info!(logger, "Triggering rebroadcast/fee-bump for request with inputs {:?}", inputs);
+ bump_requests.push((*claim_id, request.clone()));
+ }
+ for (claim_id, request) in bump_requests {
+ self.generate_claim(current_height, &request, &feerate_strategy, fee_estimator, logger)
+ .map(|(_, new_feerate, claim)| {
+ let mut bumped_feerate = false;
+ if let Some(mut_request) = self.pending_claim_requests.get_mut(&claim_id) {
+ bumped_feerate = request.previous_feerate() > new_feerate;
+ mut_request.set_feerate(new_feerate);
+ }
+ match claim {
+ OnchainClaim::Tx(tx) => {
+ if tx.is_fully_signed() {
+ let log_start = if bumped_feerate { "Broadcasting RBF-bumped" } else { "Rebroadcasting" };
+ log_info!(logger, "{} onchain {}", log_start, log_tx!(tx.0));
+ broadcaster.broadcast_transactions(&[&tx.0]);
+ } else {
+ log_info!(logger, "Waiting for signature of unsigned onchain transaction {}", tx.0.txid());
+ }
+ },
+ OnchainClaim::Event(event) => {
+ let log_start = if bumped_feerate { "Yielding fee-bumped" } else { "Replaying" };
+ log_info!(logger, "{} onchain event to spend inputs {:?}", log_start,
+ request.outpoints());
+ #[cfg(debug_assertions)] {
+ debug_assert!(request.requires_external_funding());
+ let num_existing = self.pending_claim_events.iter()
+ .filter(|entry| entry.0 == claim_id).count();
+ assert!(num_existing == 0 || num_existing == 1);
+ }
+ self.pending_claim_events.retain(|event| event.0 != claim_id);
+ self.pending_claim_events.push((claim_id, event));
+ }
+ }
+ });
+ }
+ }
+
+ /// Lightning security model (i.e being able to redeem/timeout HTLC or penalize counterparty
+ /// onchain) lays on the assumption of claim transactions getting confirmed before timelock
+ /// expiration (CSV or CLTV following cases). In case of high-fee spikes, claim tx may get stuck
+ /// in the mempool, so you need to bump its feerate quickly using Replace-By-Fee or
+ /// Child-Pay-For-Parent.
+ ///
+ /// Panics if there are signing errors, because signing operations in reaction to on-chain
+ /// events are not expected to fail, and if they do, we may lose funds.
+ fn generate_claim<F: Deref, L: Logger>(
+ &mut self, cur_height: u32, cached_request: &PackageTemplate, feerate_strategy: &FeerateStrategy,
+ fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L,
+ ) -> Option<(u32, u64, OnchainClaim)>
+ where F::Target: FeeEstimator,