lock on payment hash

2025-12-23 00:34:21 +01:00 · 2022-11-21 14:24:29 +01:00
parent daa70c5f0e
commit ceb3ddb1ee
1 changed files with 114 additions and 104 deletions
--- a/intercept.go
+++ b/intercept.go
@@ -2,6 +2,7 @@ package main

 import (
 	"bytes"
+	"encoding/hex"
 	"fmt"
 	"log"
 	"math/big"
@@ -12,6 +13,7 @@ import (
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/record"
 	"github.com/lightningnetwork/lnd/routing/route"
+	"golang.org/x/sync/singleflight"
 )

 type interceptAction int
@@ -30,6 +32,8 @@ var (
 	FAILURE_INCORRECT_OR_UNKNOWN_PAYMENT_DETAILS interceptFailureCode = 0x4015
 )

+var payHashGroup singleflight.Group
+
 type interceptResult struct {
 	action       interceptAction
 	failureCode  interceptFailureCode
@@ -40,122 +44,128 @@ type interceptResult struct {
 }

 func intercept(reqPaymentHash []byte, reqOutgoingAmountMsat uint64, reqOutgoingExpiry uint32) interceptResult {
-	paymentHash, paymentSecret, destination, incomingAmountMsat, outgoingAmountMsat, channelPoint, err := paymentInfo(reqPaymentHash)
-	if err != nil {
-		log.Printf("paymentInfo(%x) error: %v", reqPaymentHash, err)
-		return interceptResult{
-			action: INTERCEPT_FAIL_HTLC,
+	reqPaymentHashStr := hex.EncodeToString(reqPaymentHash)
+	resp, _, _ := payHashGroup.Do(reqPaymentHashStr, func() (interface{}, error) {
+		paymentHash, paymentSecret, destination, incomingAmountMsat, outgoingAmountMsat, channelPoint, err := paymentInfo(reqPaymentHash)
+		if err != nil {
+			log.Printf("paymentInfo(%x) error: %v", reqPaymentHash, err)
+			return interceptResult{
+				action: INTERCEPT_FAIL_HTLC,
+			}, nil
 		}
-	}
-	log.Printf("paymentHash:%x\npaymentSecret:%x\ndestination:%x\nincomingAmountMsat:%v\noutgoingAmountMsat:%v\n\n",
-		paymentHash, paymentSecret, destination, incomingAmountMsat, outgoingAmountMsat)
-	if paymentSecret != nil {
+		log.Printf("paymentHash:%x\npaymentSecret:%x\ndestination:%x\nincomingAmountMsat:%v\noutgoingAmountMsat:%v\n\n",
+			paymentHash, paymentSecret, destination, incomingAmountMsat, outgoingAmountMsat)
+		if paymentSecret != nil {

-		if channelPoint == nil {
-			if bytes.Equal(paymentHash, reqPaymentHash) {
-				channelPoint, err = openChannel(client, reqPaymentHash, destination, incomingAmountMsat)
-				log.Printf("openChannel(%x, %v) err: %v", destination, incomingAmountMsat, err)
-				if err != nil {
-					return interceptResult{
-						action: INTERCEPT_FAIL_HTLC,
+			if channelPoint == nil {
+				if bytes.Equal(paymentHash, reqPaymentHash) {
+					channelPoint, err = openChannel(client, reqPaymentHash, destination, incomingAmountMsat)
+					log.Printf("openChannel(%x, %v) err: %v", destination, incomingAmountMsat, err)
+					if err != nil {
+						return interceptResult{
+							action: INTERCEPT_FAIL_HTLC,
+						}, nil
+					}
+				} else { //probing
+					failureCode := FAILURE_TEMPORARY_CHANNEL_FAILURE
+					isConnected, _ := client.IsConnected(destination)
+					if err != nil || !*isConnected {
+						failureCode = FAILURE_INCORRECT_OR_UNKNOWN_PAYMENT_DETAILS
 					}
-				}
-			} else { //probing
-				failureCode := FAILURE_TEMPORARY_CHANNEL_FAILURE
-				isConnected, _ := client.IsConnected(destination)
-				if err != nil || !*isConnected {
-					failureCode = FAILURE_INCORRECT_OR_UNKNOWN_PAYMENT_DETAILS
-				}

+					return interceptResult{
+						action:      INTERCEPT_FAIL_HTLC_WITH_CODE,
+						failureCode: failureCode,
+					}, 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: failureCode,
-				}
+					action: INTERCEPT_FAIL_HTLC,
+				}, nil
+			}
+
+			sessionKey, err := btcec.NewPrivateKey()
+			if err != nil {
+				log.Printf("btcec.NewPrivateKey(): %v", err)
+				return interceptResult{
+					action: INTERCEPT_FAIL_HTLC,
+				}, 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,
+				}, nil
+			}
+
+			payload, err := sphinx.NewHopPayload(nil, b.Bytes())
+			if err != nil {
+				log.Printf("sphinx.NewHopPayload(): %v", err)
+				return interceptResult{
+					action: INTERCEPT_FAIL_HTLC,
+				}, 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,
+				}, nil
+			}
+			var onionBlob bytes.Buffer
+			err = sphinxPacket.Encode(&onionBlob)
+			if err != nil {
+				log.Printf("sphinxPacket.Encode(): %v", err)
+				return interceptResult{
+					action: INTERCEPT_FAIL_HTLC,
+				}, nil
 			}
-		}

-		pubKey, err := btcec.ParsePubKey(destination)
-		if err != nil {
-			log.Printf("btcec.ParsePubKey(%x): %v", destination, err)
 			return interceptResult{
-				action: INTERCEPT_FAIL_HTLC,
-			}
-		}
-
-		sessionKey, err := btcec.NewPrivateKey()
-		if err != nil {
-			log.Printf("btcec.NewPrivateKey(): %v", err)
+				action:       INTERCEPT_RESUME_OR_CANCEL,
+				destination:  destination,
+				channelPoint: channelPoint,
+				amountMsat:   uint64(amt),
+				onionBlob:    onionBlob.Bytes(),
+			}, nil
+		} else {
 			return interceptResult{
-				action: INTERCEPT_FAIL_HTLC,
-			}
+				action: INTERCEPT_RESUME,
+			}, 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,
-			}
-		}
-
-		payload, err := sphinx.NewHopPayload(nil, b.Bytes())
-		if err != nil {
-			log.Printf("sphinx.NewHopPayload(): %v", err)
-			return interceptResult{
-				action: INTERCEPT_FAIL_HTLC,
-			}
-		}
-
-		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,
-			}
-		}
-		var onionBlob bytes.Buffer
-		err = sphinxPacket.Encode(&onionBlob)
-		if err != nil {
-			log.Printf("sphinxPacket.Encode(): %v", err)
-			return interceptResult{
-				action: INTERCEPT_FAIL_HTLC,
-			}
-		}
-
-		return interceptResult{
-			action:       INTERCEPT_RESUME_OR_CANCEL,
-			destination:  destination,
-			channelPoint: channelPoint,
-			amountMsat:   uint64(amt),
-			onionBlob:    onionBlob.Bytes(),
-		}
-	} else {
-		return interceptResult{
-			action: INTERCEPT_RESUME,
-		}
-	}
+	return resp.(interceptResult)
 }
+
 func checkPayment(incomingAmountMsat, outgoingAmountMsat int64) error {
 	fees := incomingAmountMsat * channelFeePermyriad / 10_000 / 1_000 * 1_000
 	if fees < channelMinimumFeeMsat {