Files
lspd/interceptor/intercept.go
2023-06-02 13:32:49 +02:00

356 lines
11 KiB
Go

package interceptor
import (
"bytes"
"context"
"encoding/hex"
"fmt"
"log"
"math/big"
"time"
"github.com/breez/lspd/basetypes"
"github.com/breez/lspd/chain"
"github.com/breez/lspd/config"
"github.com/breez/lspd/lightning"
"github.com/btcsuite/btcd/btcec/v2"
"github.com/btcsuite/btcd/wire"
sphinx "github.com/lightningnetwork/lightning-onion"
"github.com/lightningnetwork/lnd/lnwire"
"github.com/lightningnetwork/lnd/record"
"github.com/lightningnetwork/lnd/routing/route"
"golang.org/x/sync/singleflight"
)
type InterceptAction int
const (
INTERCEPT_RESUME InterceptAction = 0
INTERCEPT_RESUME_WITH_ONION InterceptAction = 1
INTERCEPT_FAIL_HTLC_WITH_CODE InterceptAction = 2
)
type InterceptFailureCode uint16
var (
FAILURE_TEMPORARY_CHANNEL_FAILURE InterceptFailureCode = 0x1007
FAILURE_TEMPORARY_NODE_FAILURE InterceptFailureCode = 0x2002
FAILURE_INCORRECT_OR_UNKNOWN_PAYMENT_DETAILS InterceptFailureCode = 0x400F
)
type InterceptResult struct {
Action InterceptAction
FailureCode InterceptFailureCode
Destination []byte
AmountMsat uint64
ChannelPoint *wire.OutPoint
ChannelId uint64
OnionBlob []byte
}
type Interceptor struct {
client lightning.Client
config *config.NodeConfig
store InterceptStore
feeEstimator chain.FeeEstimator
feeStrategy chain.FeeStrategy
payHashGroup singleflight.Group
}
func NewInterceptor(
client lightning.Client,
config *config.NodeConfig,
store InterceptStore,
feeEstimator chain.FeeEstimator,
feeStrategy chain.FeeStrategy,
) *Interceptor {
return &Interceptor{
client: client,
config: config,
store: store,
feeEstimator: feeEstimator,
feeStrategy: feeStrategy,
}
}
func (i *Interceptor) Intercept(nextHop string, reqPaymentHash []byte, reqOutgoingAmountMsat uint64, reqOutgoingExpiry uint32, reqIncomingExpiry uint32) InterceptResult {
reqPaymentHashStr := hex.EncodeToString(reqPaymentHash)
resp, _, _ := i.payHashGroup.Do(reqPaymentHashStr, func() (interface{}, error) {
params, paymentHash, paymentSecret, destination, incomingAmountMsat, outgoingAmountMsat, channelPoint, tag, err := i.store.PaymentInfo(reqPaymentHash)
if err != nil {
log.Printf("paymentInfo(%x) error: %v", reqPaymentHash, err)
return InterceptResult{
Action: INTERCEPT_FAIL_HTLC_WITH_CODE,
FailureCode: FAILURE_TEMPORARY_NODE_FAILURE,
}, nil
}
log.Printf("paymentHash:%x\npaymentSecret:%x\ndestination:%x\nincomingAmountMsat:%v\noutgoingAmountMsat:%v",
paymentHash, paymentSecret, destination, incomingAmountMsat, outgoingAmountMsat)
if paymentSecret == nil || (nextHop != "<unknown>" && nextHop != hex.EncodeToString(destination)) {
return InterceptResult{
Action: INTERCEPT_RESUME,
}, nil
}
if channelPoint == nil {
if bytes.Equal(paymentHash, reqPaymentHash) {
// TODO: When opening_fee_params is enforced, turn this check in a temporary channel failure.
if params == nil {
log.Printf("DEPRECATED: Intercepted htlc with deprecated fee mechanism.")
params = &OpeningFeeParams{
MinMsat: uint64(i.config.ChannelMinimumFeeMsat),
Proportional: uint32(i.config.ChannelFeePermyriad * 100),
ValidUntil: time.Now().UTC().Add(time.Duration(time.Hour * 24)).Format(basetypes.TIME_FORMAT),
MaxIdleTime: uint32(i.config.MaxInactiveDuration / 600),
MaxClientToSelfDelay: uint32(10000),
}
}
if int64(reqIncomingExpiry)-int64(reqOutgoingExpiry) < int64(i.config.TimeLockDelta) {
return InterceptResult{
Action: INTERCEPT_FAIL_HTLC_WITH_CODE,
FailureCode: FAILURE_TEMPORARY_CHANNEL_FAILURE,
}, nil
}
validUntil, err := time.Parse(basetypes.TIME_FORMAT, params.ValidUntil)
if err != nil {
log.Printf("time.Parse(%s, %s) failed. Failing channel open: %v", basetypes.TIME_FORMAT, params.ValidUntil, err)
return InterceptResult{
Action: INTERCEPT_FAIL_HTLC_WITH_CODE,
FailureCode: FAILURE_TEMPORARY_CHANNEL_FAILURE,
}, nil
}
if time.Now().UTC().After(validUntil) {
if !i.isCurrentChainFeeCheaper(params) {
log.Printf("Intercepted expired payment registration. Failing payment. payment hash: %x, valid until: %s", paymentHash, params.ValidUntil)
return InterceptResult{
Action: INTERCEPT_FAIL_HTLC_WITH_CODE,
FailureCode: FAILURE_TEMPORARY_CHANNEL_FAILURE,
}, nil
}
log.Printf("Intercepted expired payment registration. Opening channel anyway, because it's cheaper at the current rate. %+v", params)
}
channelPoint, err = i.openChannel(reqPaymentHash, destination, incomingAmountMsat, tag)
if err != nil {
log.Printf("openChannel(%x, %v) err: %v", destination, incomingAmountMsat, err)
return InterceptResult{
Action: INTERCEPT_FAIL_HTLC_WITH_CODE,
FailureCode: FAILURE_TEMPORARY_CHANNEL_FAILURE,
}, nil
}
} else { //probing
return InterceptResult{
Action: INTERCEPT_FAIL_HTLC_WITH_CODE,
FailureCode: FAILURE_INCORRECT_OR_UNKNOWN_PAYMENT_DETAILS,
}, nil
}
}
pubKey, err := btcec.ParsePubKey(destination)
if err != nil {
log.Printf("btcec.ParsePubKey(%x): %v", destination, err)
return InterceptResult{
Action: INTERCEPT_FAIL_HTLC_WITH_CODE,
FailureCode: FAILURE_TEMPORARY_CHANNEL_FAILURE,
}, nil
}
sessionKey, err := btcec.NewPrivateKey()
if err != nil {
log.Printf("btcec.NewPrivateKey(): %v", err)
return InterceptResult{
Action: INTERCEPT_FAIL_HTLC_WITH_CODE,
FailureCode: FAILURE_TEMPORARY_CHANNEL_FAILURE,
}, nil
}
var bigProd, bigAmt big.Int
amt := (bigAmt.Div(bigProd.Mul(big.NewInt(outgoingAmountMsat), big.NewInt(int64(reqOutgoingAmountMsat))), big.NewInt(incomingAmountMsat))).Int64()
var addr [32]byte
copy(addr[:], paymentSecret)
hop := route.Hop{
AmtToForward: lnwire.MilliSatoshi(amt),
OutgoingTimeLock: reqOutgoingExpiry,
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)
return InterceptResult{
Action: INTERCEPT_FAIL_HTLC_WITH_CODE,
FailureCode: FAILURE_TEMPORARY_CHANNEL_FAILURE,
}, nil
}
payload, err := sphinx.NewHopPayload(nil, b.Bytes())
if err != nil {
log.Printf("sphinx.NewHopPayload(): %v", err)
return InterceptResult{
Action: INTERCEPT_FAIL_HTLC_WITH_CODE,
FailureCode: FAILURE_TEMPORARY_CHANNEL_FAILURE,
}, nil
}
var sphinxPath sphinx.PaymentPath
sphinxPath[0] = sphinx.OnionHop{
NodePub: *pubKey,
HopPayload: payload,
}
sphinxPacket, err := sphinx.NewOnionPacket(
&sphinxPath, sessionKey, reqPaymentHash,
sphinx.DeterministicPacketFiller,
)
if err != nil {
log.Printf("sphinx.NewOnionPacket(): %v", err)
return InterceptResult{
Action: INTERCEPT_FAIL_HTLC_WITH_CODE,
FailureCode: FAILURE_TEMPORARY_CHANNEL_FAILURE,
}, nil
}
var onionBlob bytes.Buffer
err = sphinxPacket.Encode(&onionBlob)
if err != nil {
log.Printf("sphinxPacket.Encode(): %v", err)
return InterceptResult{
Action: INTERCEPT_FAIL_HTLC_WITH_CODE,
FailureCode: FAILURE_TEMPORARY_CHANNEL_FAILURE,
}, nil
}
deadline := time.Now().Add(60 * time.Second)
for {
chanResult, _ := i.client.GetChannel(destination, *channelPoint)
if chanResult != nil {
log.Printf("channel opended successfully alias: %v, confirmed: %v", chanResult.InitialChannelID.ToString(), chanResult.ConfirmedChannelID.ToString())
err := i.store.InsertChannel(
uint64(chanResult.InitialChannelID),
uint64(chanResult.ConfirmedChannelID),
channelPoint.String(),
destination,
time.Now(),
)
if err != nil {
log.Printf("insertChannel error: %v", err)
return InterceptResult{
Action: INTERCEPT_FAIL_HTLC_WITH_CODE,
FailureCode: FAILURE_TEMPORARY_CHANNEL_FAILURE,
}, nil
}
channelID := uint64(chanResult.ConfirmedChannelID)
if channelID == 0 {
channelID = uint64(chanResult.InitialChannelID)
}
return InterceptResult{
Action: INTERCEPT_RESUME_WITH_ONION,
Destination: destination,
ChannelPoint: channelPoint,
ChannelId: channelID,
AmountMsat: uint64(amt),
OnionBlob: onionBlob.Bytes(),
}, nil
}
log.Printf("waiting for channel to get opened.... %v\n", destination)
if time.Now().After(deadline) {
log.Printf("Stop retrying getChannel(%v, %v)", destination, channelPoint.String())
break
}
<-time.After(1 * time.Second)
}
log.Printf("Error: Channel failed to opened... timed out. ")
return InterceptResult{
Action: INTERCEPT_FAIL_HTLC_WITH_CODE,
FailureCode: FAILURE_TEMPORARY_CHANNEL_FAILURE,
}, nil
})
return resp.(InterceptResult)
}
func (i *Interceptor) isCurrentChainFeeCheaper(params *OpeningFeeParams) bool {
settings, err := i.store.GetFeeParamsSettings()
if err != nil {
log.Printf("Failed to get fee params settings: %v", err)
return false
}
for _, setting := range settings {
if setting.Params.MinMsat <= params.MinMsat {
return true
}
}
return false
}
func (i *Interceptor) openChannel(paymentHash, destination []byte, incomingAmountMsat int64, tag *string) (*wire.OutPoint, error) {
capacity := incomingAmountMsat/1000 + i.config.AdditionalChannelCapacity
if capacity == i.config.PublicChannelAmount {
capacity++
}
var targetConf *uint32
confStr := "<nil>"
var feeEstimation *float64
feeStr := "<nil>"
if i.feeEstimator != nil {
fee, err := i.feeEstimator.EstimateFeeRate(
context.Background(),
i.feeStrategy,
)
if err == nil {
feeEstimation = &fee.SatPerVByte
feeStr = fmt.Sprintf("%.5f", *feeEstimation)
} else {
log.Printf("Error estimating chain fee, fallback to target conf: %v", err)
targetConf = &i.config.TargetConf
confStr = fmt.Sprintf("%v", *targetConf)
}
}
log.Printf(
"Opening zero conf channel. Destination: %x, capacity: %v, fee: %s, targetConf: %s",
destination,
capacity,
feeStr,
confStr,
)
channelPoint, err := i.client.OpenChannel(&lightning.OpenChannelRequest{
Destination: destination,
CapacitySat: uint64(capacity),
MinConfs: i.config.MinConfs,
IsPrivate: true,
IsZeroConf: true,
FeeSatPerVByte: feeEstimation,
TargetConf: targetConf,
})
if err != nil {
log.Printf("client.OpenChannelSync(%x, %v) error: %v", destination, capacity, err)
return nil, err
}
sendOpenChannelEmailNotification(
paymentHash,
incomingAmountMsat,
destination,
capacity,
channelPoint.String(),
tag,
)
err = i.store.SetFundingTx(paymentHash, channelPoint)
return channelPoint, err
}