Files
lspd/intercept.go
2022-07-17 18:05:58 +03:00

298 lines
9.8 KiB
Go

package main
import (
"bytes"
"context"
"encoding/hex"
"fmt"
"log"
"math/big"
"os"
"time"
"github.com/btcsuite/btcd/btcec/v2"
"github.com/btcsuite/btcd/chaincfg/chainhash"
"github.com/btcsuite/btcd/wire"
"github.com/lightningnetwork/lnd/lnrpc"
"github.com/lightningnetwork/lnd/lnrpc/routerrpc"
"github.com/lightningnetwork/lnd/lnwire"
"github.com/lightningnetwork/lnd/record"
"github.com/lightningnetwork/lnd/routing/route"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/metadata"
"google.golang.org/grpc/status"
sphinx "github.com/lightningnetwork/lightning-onion"
)
func checkPayment(incomingAmountMsat, outgoingAmountMsat int64) error {
fees := incomingAmountMsat * channelFeePermyriad / 10_000 / 1_000 * 1_000
if fees < channelMinimumFeeMsat {
fees = channelMinimumFeeMsat
}
if incomingAmountMsat-outgoingAmountMsat < fees {
return fmt.Errorf("not enough fees")
}
return nil
}
func isConnected(ctx context.Context, client lnrpc.LightningClient, destination []byte) error {
pubKey := hex.EncodeToString(destination)
r, err := client.ListPeers(ctx, &lnrpc.ListPeersRequest{LatestError: true})
if err != nil {
log.Printf("client.ListPeers() error: %v", err)
return fmt.Errorf("client.ListPeers() error: %w", err)
}
for _, peer := range r.Peers {
if pubKey == peer.PubKey {
log.Printf("destination online: %x", destination)
return nil
}
}
log.Printf("destination offline: %x", destination)
return fmt.Errorf("destination offline")
}
func openChannel(ctx context.Context, client lnrpc.LightningClient, paymentHash, destination []byte, incomingAmountMsat int64) ([]byte, uint32, error) {
capacity := incomingAmountMsat/1000 + additionalChannelCapacity
if capacity == publicChannelAmount {
capacity++
}
channelPoint, err := client.OpenChannelSync(ctx, &lnrpc.OpenChannelRequest{
NodePubkey: destination,
LocalFundingAmount: capacity,
TargetConf: 6,
Private: true,
})
if err != nil {
log.Printf("client.OpenChannelSync(%x, %v) error: %v", destination, capacity, err)
return nil, 0, err
}
sendOpenChannelEmailNotification(
paymentHash,
incomingAmountMsat,
destination,
capacity,
channelPoint.GetFundingTxidBytes(),
channelPoint.OutputIndex,
)
err = setFundingTx(paymentHash, channelPoint.GetFundingTxidBytes(), int(channelPoint.OutputIndex))
return channelPoint.GetFundingTxidBytes(), channelPoint.OutputIndex, err
}
func getChannel(ctx context.Context, client lnrpc.LightningClient, node []byte, channelPoint string) uint64 {
r, err := client.ListChannels(ctx, &lnrpc.ListChannelsRequest{Peer: node})
if err != nil {
log.Printf("client.ListChannels(%x) error: %v", node, err)
return 0
}
for _, c := range r.Channels {
log.Printf("getChannel(%x): %v", node, c.ChanId)
if c.ChannelPoint == channelPoint && c.Active {
return c.ChanId
}
}
log.Printf("No channel found: getChannel(%x)", node)
return 0
}
func failForwardSend(interceptorClient routerrpc.Router_HtlcInterceptorClient, incomingCircuitKey *routerrpc.CircuitKey) {
interceptorClient.Send(&routerrpc.ForwardHtlcInterceptResponse{
IncomingCircuitKey: incomingCircuitKey,
Action: routerrpc.ResolveHoldForwardAction_FAIL,
})
}
func intercept() {
for {
cancellableCtx, cancel := context.WithCancel(context.Background())
clientCtx := metadata.AppendToOutgoingContext(cancellableCtx, "macaroon", os.Getenv("LND_MACAROON_HEX"))
interceptorClient, err := routerClient.HtlcInterceptor(clientCtx)
if err != nil {
log.Printf("routerClient.HtlcInterceptor(): %v", err)
cancel()
time.Sleep(1 * time.Second)
continue
}
for {
request, err := interceptorClient.Recv()
if err != nil {
// If it is just the error result of the context cancellation
// the we exit silently.
status, ok := status.FromError(err)
if ok && status.Code() == codes.Canceled {
break
}
// Otherwise it an unexpected error, we fail the test.
log.Printf("unexpected error in interceptor.Recv() %v", err)
cancel()
break
}
fmt.Printf("htlc: %v\nchanID: %v\nincoming amount: %v\noutgoing amount: %v\nincomin expiry: %v\noutgoing expiry: %v\npaymentHash: %x\nonionBlob: %x\n\n",
request.IncomingCircuitKey.HtlcId,
request.IncomingCircuitKey.ChanId,
request.IncomingAmountMsat,
request.OutgoingAmountMsat,
request.IncomingExpiry,
request.OutgoingExpiry,
request.PaymentHash,
request.OnionBlob,
)
paymentHash, paymentSecret, destination, incomingAmountMsat, outgoingAmountMsat, fundingTxID, fundingTxOutnum, err := paymentInfo(request.PaymentHash)
if err != nil {
log.Printf("paymentInfo(%x) error: %v", request.PaymentHash, err)
failForwardSend(interceptorClient, request.IncomingCircuitKey)
continue
}
log.Printf("paymentHash:%x\npaymentSecret:%x\ndestination:%x\nincomingAmountMsat:%v\noutgoingAmountMsat:%v\n\n",
paymentHash, paymentSecret, destination, incomingAmountMsat, outgoingAmountMsat)
if paymentSecret != nil {
if fundingTxID == nil {
if bytes.Compare(paymentHash, request.PaymentHash) == 0 {
fundingTxID, fundingTxOutnum, err = openChannel(clientCtx, client, request.PaymentHash, destination, incomingAmountMsat)
log.Printf("openChannel(%x, %v) err: %v", destination, incomingAmountMsat, err)
if err != nil {
failForwardSend(interceptorClient, request.IncomingCircuitKey)
continue
}
} else { //probing
failureCode := lnrpc.Failure_TEMPORARY_CHANNEL_FAILURE
if err := isConnected(clientCtx, client, destination); err == nil {
failureCode = lnrpc.Failure_INCORRECT_OR_UNKNOWN_PAYMENT_DETAILS
}
interceptorClient.Send(&routerrpc.ForwardHtlcInterceptResponse{
IncomingCircuitKey: request.IncomingCircuitKey,
Action: routerrpc.ResolveHoldForwardAction_FAIL,
FailureCode: failureCode,
})
continue
}
}
pubKey, err := btcec.ParsePubKey(destination)
if err != nil {
log.Printf("btcec.ParsePubKey(%x): %v", destination, err)
failForwardSend(interceptorClient, request.IncomingCircuitKey)
continue
}
sessionKey, err := btcec.NewPrivateKey()
if err != nil {
log.Printf("btcec.NewPrivateKey(): %v", err)
failForwardSend(interceptorClient, request.IncomingCircuitKey)
continue
}
var bigProd, bigAmt big.Int
amt := (bigAmt.Div(bigProd.Mul(big.NewInt(outgoingAmountMsat), big.NewInt(int64(request.OutgoingAmountMsat))), big.NewInt(incomingAmountMsat))).Int64()
var addr [32]byte
copy(addr[:], paymentSecret)
hop := route.Hop{
AmtToForward: lnwire.MilliSatoshi(amt),
OutgoingTimeLock: request.OutgoingExpiry,
MPP: record.NewMPP(lnwire.MilliSatoshi(outgoingAmountMsat), addr),
CustomRecords: make(record.CustomSet),
}
var b bytes.Buffer
err = hop.PackHopPayload(&b, uint64(0))
if err != nil {
log.Printf("hop.PackHopPayload(): %v", err)
failForwardSend(interceptorClient, request.IncomingCircuitKey)
continue
}
payload, err := sphinx.NewHopPayload(nil, b.Bytes())
if err != nil {
log.Printf("sphinx.NewHopPayload(): %v", err)
failForwardSend(interceptorClient, request.IncomingCircuitKey)
continue
}
var sphinxPath sphinx.PaymentPath
sphinxPath[0] = sphinx.OnionHop{
NodePub: *pubKey,
HopPayload: payload,
}
sphinxPacket, err := sphinx.NewOnionPacket(
&sphinxPath, sessionKey, request.PaymentHash,
sphinx.DeterministicPacketFiller,
)
if err != nil {
log.Printf("sphinx.NewOnionPacket(): %v", err)
failForwardSend(interceptorClient, request.IncomingCircuitKey)
continue
}
var onionBlob bytes.Buffer
err = sphinxPacket.Encode(&onionBlob)
if err != nil {
log.Printf("sphinxPacket.Encode(): %v", err)
failForwardSend(interceptorClient, request.IncomingCircuitKey)
continue
}
var h chainhash.Hash
err = h.SetBytes(fundingTxID)
if err != nil {
log.Printf("h.SetBytes(%x) error: %v", fundingTxID, err)
failForwardSend(interceptorClient, request.IncomingCircuitKey)
continue
}
channelPoint := wire.NewOutPoint(&h, fundingTxOutnum).String()
go resumeOrCancel(
clientCtx, interceptorClient, request.IncomingCircuitKey, destination,
channelPoint, uint64(amt), onionBlob.Bytes(),
)
} else {
interceptorClient.Send(&routerrpc.ForwardHtlcInterceptResponse{
IncomingCircuitKey: request.IncomingCircuitKey,
Action: routerrpc.ResolveHoldForwardAction_RESUME,
OutgoingAmountMsat: request.OutgoingAmountMsat,
OutgoingRequestedChanId: request.OutgoingRequestedChanId,
OnionBlob: request.OnionBlob,
})
}
}
}
}
func resumeOrCancel(
ctx context.Context,
interceptorClient routerrpc.Router_HtlcInterceptorClient,
incomingCircuitKey *routerrpc.CircuitKey,
destination []byte,
channelPoint string,
outgoingAmountMsat uint64,
onionBlob []byte,
) {
deadline := time.Now().Add(10 * time.Second)
for {
chanID := getChannel(ctx, client, destination, channelPoint)
if chanID != 0 {
interceptorClient.Send(&routerrpc.ForwardHtlcInterceptResponse{
IncomingCircuitKey: incomingCircuitKey,
Action: routerrpc.ResolveHoldForwardAction_RESUME,
OutgoingAmountMsat: outgoingAmountMsat,
OutgoingRequestedChanId: chanID,
OnionBlob: onionBlob,
})
err := insertChannel(chanID, channelPoint, destination, time.Now())
if err != nil {
log.Printf("insertChannel error: %v", err)
}
return
}
log.Printf("getChannel(%x, %v) returns 0", destination, channelPoint)
if time.Now().After(deadline) {
log.Printf("Stop retrying getChannel(%x, %v)", destination, channelPoint)
break
}
time.Sleep(1 * time.Second)
}
failForwardSend(interceptorClient, incomingCircuitKey)
}