htlcswitch: extract exit hop processing to method
This commit is contained in:
parent
9643b45dbc
commit
eb598ec7a4
@ -2354,227 +2354,19 @@ func (l *channelLink) processRemoteAdds(fwdPkg *channeldb.FwdPkg,
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fwdInfo := chanIterator.ForwardingInstructions()
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switch fwdInfo.NextHop {
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case exitHop:
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// If hodl.ExitSettle is requested, we will not validate
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// the final hop's ADD, nor will we settle the
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// corresponding invoice or respond with the preimage.
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if l.cfg.DebugHTLC &&
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l.cfg.HodlMask.Active(hodl.ExitSettle) {
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l.warnf(hodl.ExitSettle.Warning())
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continue
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}
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// First, we'll check the expiry of the HTLC itself
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// against, the current block height. If the timeout is
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// too soon, then we'll reject the HTLC.
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if pd.Timeout-expiryGraceDelta <= heightNow {
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log.Errorf("htlc(%x) has an expiry that's too "+
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"soon: expiry=%v, best_height=%v",
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pd.RHash[:], pd.Timeout, heightNow)
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failure := lnwire.FailFinalExpiryTooSoon{}
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l.sendHTLCError(
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pd.HtlcIndex, &failure, obfuscator, pd.SourceRef,
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)
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needUpdate = true
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continue
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}
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// We're the designated payment destination. Therefore
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// we attempt to see if we have an invoice locally
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// which'll allow us to settle this htlc.
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invoiceHash := lntypes.Hash(pd.RHash)
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invoice, minCltvDelta, err := l.cfg.Registry.LookupInvoice(
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invoiceHash,
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)
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if err != nil {
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log.Errorf("unable to query invoice registry: "+
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" %v", err)
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failure := lnwire.NewFailUnknownPaymentHash(
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pd.Amount,
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)
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l.sendHTLCError(
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pd.HtlcIndex, failure, obfuscator, pd.SourceRef,
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)
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needUpdate = true
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continue
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}
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// Reject htlcs for canceled invoices.
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if invoice.Terms.State == channeldb.ContractCanceled {
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l.errorf("Rejecting htlc due to canceled " +
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"invoice")
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failure := lnwire.NewFailUnknownPaymentHash(
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pd.Amount,
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)
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l.sendHTLCError(
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pd.HtlcIndex, failure, obfuscator,
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pd.SourceRef,
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)
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needUpdate = true
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continue
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}
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// If the invoice is already settled, we choose to
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// accept the payment to simplify failure recovery.
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//
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// NOTE: Though our recovery and forwarding logic is
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// predominately batched, settling invoices happens
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// iteratively. We may reject one of two payments
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// for the same rhash at first, but then restart and
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// reject both after seeing that the invoice has been
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// settled. Without any record of which one settles
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// first, it is ambiguous as to which one actually
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// settled the invoice. Thus, by accepting all
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// payments, we eliminate the race condition that can
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// lead to this inconsistency.
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//
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// TODO(conner): track ownership of settlements to
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// properly recover from failures? or add batch invoice
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// settlement
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if invoice.Terms.State != channeldb.ContractOpen {
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log.Warnf("Accepting duplicate payment for "+
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"hash=%x", pd.RHash[:])
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}
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// If we're not currently in debug mode, and the
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// extended htlc doesn't meet the value requested, then
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// we'll fail the htlc. Otherwise, we settle this htlc
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// within our local state update log, then send the
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// update entry to the remote party.
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//
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// NOTE: We make an exception when the value requested
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// by the invoice is zero. This means the invoice
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// allows the payee to specify the amount of satoshis
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// they wish to send. So since we expect the htlc to
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// have a different amount, we should not fail.
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if !l.cfg.DebugHTLC && invoice.Terms.Value > 0 &&
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pd.Amount < invoice.Terms.Value {
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log.Errorf("rejecting htlc due to incorrect "+
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"amount: expected %v, received %v",
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invoice.Terms.Value, pd.Amount)
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failure := lnwire.NewFailUnknownPaymentHash(
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pd.Amount,
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)
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l.sendHTLCError(
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pd.HtlcIndex, failure, obfuscator, pd.SourceRef,
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)
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needUpdate = true
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continue
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}
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// As we're the exit hop, we'll double check the
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// hop-payload included in the HTLC to ensure that it
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// was crafted correctly by the sender and matches the
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// HTLC we were extended.
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//
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// NOTE: We make an exception when the value requested
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// by the invoice is zero. This means the invoice
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// allows the payee to specify the amount of satoshis
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// they wish to send. So since we expect the htlc to
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// have a different amount, we should not fail.
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if !l.cfg.DebugHTLC && invoice.Terms.Value > 0 &&
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fwdInfo.AmountToForward < invoice.Terms.Value {
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log.Errorf("Onion payload of incoming htlc(%x) "+
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"has incorrect value: expected %v, "+
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"got %v", pd.RHash, invoice.Terms.Value,
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fwdInfo.AmountToForward)
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failure := lnwire.NewFailUnknownPaymentHash(
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pd.Amount,
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)
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l.sendHTLCError(
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pd.HtlcIndex, failure, obfuscator, pd.SourceRef,
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)
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needUpdate = true
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continue
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}
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// We'll also ensure that our time-lock value has been
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// computed correctly.
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expectedHeight := heightNow + minCltvDelta
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switch {
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case !l.cfg.DebugHTLC && pd.Timeout < expectedHeight:
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log.Errorf("Incoming htlc(%x) has an "+
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"expiration that is too soon: "+
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"expected at least %v, got %v",
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pd.RHash[:], expectedHeight, pd.Timeout)
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failure := lnwire.FailFinalExpiryTooSoon{}
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l.sendHTLCError(
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pd.HtlcIndex, failure, obfuscator,
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pd.SourceRef,
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)
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needUpdate = true
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continue
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case !l.cfg.DebugHTLC && pd.Timeout != fwdInfo.OutgoingCTLV:
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log.Errorf("HTLC(%x) has incorrect "+
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"time-lock: expected %v, got %v",
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pd.RHash[:], pd.Timeout,
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fwdInfo.OutgoingCTLV)
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failure := lnwire.NewFinalIncorrectCltvExpiry(
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fwdInfo.OutgoingCTLV,
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)
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l.sendHTLCError(
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pd.HtlcIndex, failure, obfuscator, pd.SourceRef,
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)
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needUpdate = true
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continue
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}
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preimage := invoice.Terms.PaymentPreimage
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err = l.channel.SettleHTLC(
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preimage, pd.HtlcIndex, pd.SourceRef, nil, nil,
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updated, err := l.processExitHop(
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pd, obfuscator, fwdInfo, heightNow,
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)
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if err != nil {
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l.fail(LinkFailureError{code: ErrInternalError},
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"unable to settle htlc: %v", err)
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return false
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}
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// Notify the invoiceRegistry of the invoices we just
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// settled (with the amount accepted at settle time)
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// with this latest commitment update.
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err = l.cfg.Registry.SettleInvoice(
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invoiceHash, pd.Amount,
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err.Error(),
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)
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if err != nil {
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l.fail(LinkFailureError{code: ErrInternalError},
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"unable to settle invoice: %v", err)
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return false
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}
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l.infof("settling %x as exit hop", pd.RHash)
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// If the link is in hodl.BogusSettle mode, replace the
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// preimage with a fake one before sending it to the
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// peer.
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if l.cfg.DebugHTLC &&
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l.cfg.HodlMask.Active(hodl.BogusSettle) {
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l.warnf(hodl.BogusSettle.Warning())
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preimage = [32]byte{}
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copy(preimage[:], bytes.Repeat([]byte{2}, 32))
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}
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// HTLC was successfully settled locally send
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// notification about it remote peer.
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l.cfg.Peer.SendMessage(false, &lnwire.UpdateFulfillHTLC{
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ChanID: l.ChanID(),
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ID: pd.HtlcIndex,
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PaymentPreimage: preimage,
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})
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if updated {
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needUpdate = true
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}
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// There are additional channels left within this route. So
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// we'll simply do some forwarding package book-keeping.
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@ -2733,6 +2525,178 @@ func (l *channelLink) processRemoteAdds(fwdPkg *channeldb.FwdPkg,
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return needUpdate
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}
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// processExitHop handles an htlc for which this link is the exit hop. It
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// returns a boolean indicating whether the commitment tx needs an update.
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func (l *channelLink) processExitHop(pd *lnwallet.PaymentDescriptor,
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obfuscator ErrorEncrypter, fwdInfo ForwardingInfo, heightNow uint32) (
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bool, error) {
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// If hodl.ExitSettle is requested, we will not validate the final hop's
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// ADD, nor will we settle the corresponding invoice or respond with the
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// preimage.
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if l.cfg.DebugHTLC && l.cfg.HodlMask.Active(hodl.ExitSettle) {
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l.warnf(hodl.ExitSettle.Warning())
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return false, nil
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}
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// First, we'll check the expiry of the HTLC itself against, the current
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// block height. If the timeout is too soon, then we'll reject the HTLC.
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if pd.Timeout-expiryGraceDelta <= heightNow {
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log.Errorf("htlc(%x) has an expiry that's too soon: expiry=%v"+
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", best_height=%v", pd.RHash[:], pd.Timeout, heightNow)
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failure := lnwire.NewFinalExpiryTooSoon()
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l.sendHTLCError(pd.HtlcIndex, failure, obfuscator, pd.SourceRef)
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return true, nil
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}
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// We're the designated payment destination. Therefore we attempt to
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// see if we have an invoice locally which'll allow us to settle this
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// htlc.
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invoiceHash := lntypes.Hash(pd.RHash)
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invoice, minCltvDelta, err := l.cfg.Registry.LookupInvoice(invoiceHash)
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if err != nil {
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log.Errorf("unable to query invoice registry: %v", err)
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failure := lnwire.NewFailUnknownPaymentHash(pd.Amount)
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l.sendHTLCError(pd.HtlcIndex, failure, obfuscator, pd.SourceRef)
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return true, nil
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}
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// Reject htlcs for canceled invoices.
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if invoice.Terms.State == channeldb.ContractCanceled {
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l.errorf("Rejecting htlc due to canceled invoice")
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failure := lnwire.NewFailUnknownPaymentHash(pd.Amount)
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l.sendHTLCError(pd.HtlcIndex, failure, obfuscator, pd.SourceRef)
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return true, nil
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}
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// If the invoice is already settled, we choose to accept the payment to
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// simplify failure recovery.
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//
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// NOTE: Though our recovery and forwarding logic is predominately
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// batched, settling invoices happens iteratively. We may reject one of
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// two payments for the same rhash at first, but then restart and reject
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// both after seeing that the invoice has been settled. Without any
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// record of which one settles first, it is ambiguous as to which one
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// actually settled the invoice. Thus, by accepting all payments, we
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// eliminate the race condition that can lead to this inconsistency.
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//
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// TODO(conner): track ownership of settlements to properly recover from
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// failures? or add batch invoice settlement
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if invoice.Terms.State != channeldb.ContractOpen {
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log.Warnf("Accepting duplicate payment for hash=%x",
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pd.RHash[:])
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}
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// If we're not currently in debug mode, and the extended htlc doesn't
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// meet the value requested, then we'll fail the htlc. Otherwise, we
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// settle this htlc within our local state update log, then send the
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// update entry to the remote party.
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//
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// NOTE: We make an exception when the value requested by the invoice is
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// zero. This means the invoice allows the payee to specify the amount
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// of satoshis they wish to send. So since we expect the htlc to have a
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// different amount, we should not fail.
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if !l.cfg.DebugHTLC && invoice.Terms.Value > 0 &&
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pd.Amount < invoice.Terms.Value {
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log.Errorf("rejecting htlc due to incorrect amount: expected "+
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"%v, received %v", invoice.Terms.Value, pd.Amount)
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failure := lnwire.NewFailUnknownPaymentHash(pd.Amount)
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l.sendHTLCError(pd.HtlcIndex, failure, obfuscator, pd.SourceRef)
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return true, nil
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}
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// As we're the exit hop, we'll double check the hop-payload included in
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// the HTLC to ensure that it was crafted correctly by the sender and
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// matches the HTLC we were extended.
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//
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// NOTE: We make an exception when the value requested by the invoice is
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// zero. This means the invoice allows the payee to specify the amount
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// of satoshis they wish to send. So since we expect the htlc to have a
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// different amount, we should not fail.
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if !l.cfg.DebugHTLC && invoice.Terms.Value > 0 &&
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fwdInfo.AmountToForward < invoice.Terms.Value {
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log.Errorf("Onion payload of incoming htlc(%x) has incorrect "+
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"value: expected %v, got %v", pd.RHash,
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invoice.Terms.Value, fwdInfo.AmountToForward)
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failure := lnwire.NewFailUnknownPaymentHash(pd.Amount)
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l.sendHTLCError(pd.HtlcIndex, failure, obfuscator, pd.SourceRef)
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return true, nil
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}
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// We'll also ensure that our time-lock value has been computed
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// correctly.
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expectedHeight := heightNow + minCltvDelta
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switch {
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case !l.cfg.DebugHTLC && pd.Timeout < expectedHeight:
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log.Errorf("Incoming htlc(%x) has an expiration that is too "+
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"soon: expected at least %v, got %v",
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pd.RHash[:], expectedHeight, pd.Timeout)
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failure := lnwire.FailFinalExpiryTooSoon{}
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l.sendHTLCError(pd.HtlcIndex, failure, obfuscator, pd.SourceRef)
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return true, nil
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case !l.cfg.DebugHTLC && pd.Timeout != fwdInfo.OutgoingCTLV:
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log.Errorf("HTLC(%x) has incorrect time-lock: expected %v, "+
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"got %v", pd.RHash[:], pd.Timeout, fwdInfo.OutgoingCTLV)
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failure := lnwire.NewFinalIncorrectCltvExpiry(
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fwdInfo.OutgoingCTLV,
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)
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l.sendHTLCError(pd.HtlcIndex, failure, obfuscator, pd.SourceRef)
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return true, nil
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}
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preimage := invoice.Terms.PaymentPreimage
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err = l.channel.SettleHTLC(
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preimage, pd.HtlcIndex, pd.SourceRef, nil, nil,
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)
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if err != nil {
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return false, fmt.Errorf("unable to settle htlc: %v", err)
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}
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// Notify the invoiceRegistry of the invoices we just settled (with the
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// amount accepted at settle time) with this latest commitment update.
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err = l.cfg.Registry.SettleInvoice(invoiceHash, pd.Amount)
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if err != nil {
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return false, fmt.Errorf("unable to settle invoice: %v", err)
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}
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l.infof("settling %x as exit hop", pd.RHash)
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// If the link is in hodl.BogusSettle mode, replace the preimage with a
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// fake one before sending it to the peer.
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if l.cfg.DebugHTLC && l.cfg.HodlMask.Active(hodl.BogusSettle) {
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l.warnf(hodl.BogusSettle.Warning())
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preimage = [32]byte{}
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copy(preimage[:], bytes.Repeat([]byte{2}, 32))
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}
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// HTLC was successfully settled locally send notification about it
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// remote peer.
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l.cfg.Peer.SendMessage(false, &lnwire.UpdateFulfillHTLC{
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ChanID: l.ChanID(),
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ID: pd.HtlcIndex,
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PaymentPreimage: preimage,
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})
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return true, nil
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}
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// forwardBatch forwards the given htlcPackets to the switch, and waits on the
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// err chan for the individual responses. This method is intended to be spawned
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// as a goroutine so the responses can be handled in the background.
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