55 "context"
66 "fmt"
77 "sync"
8+ "time"
89
10+ "github.com/bottlepay/lnmux/common"
911 "github.com/bottlepay/lnmux/lnd"
1012 "github.com/bottlepay/lnmux/types"
1113 "github.com/btcsuite/btcd/chaincfg"
@@ -30,6 +32,8 @@ type Mux struct {
3032 routingPolicy RoutingPolicy
3133
3234 virtualChannel uint64
35+ muxKey common.PubKey
36+ nodeKey common.PubKey
3337}
3438
3539type MuxConfig struct {
@@ -52,9 +56,7 @@ type RoutingPolicy struct {
5256 FeeRatePpm int64
5357}
5458
55- func New (cfg * MuxConfig ) (* Mux ,
56- error ) {
57-
59+ func New (cfg * MuxConfig ) (* Mux , error ) {
5860 idKeyDesc , err := cfg .KeyRing .DeriveKey (
5961 keychain.KeyLocator {
6062 Family : keychain .KeyFamilyNodeKey ,
@@ -67,6 +69,17 @@ func New(cfg *MuxConfig) (*Mux,
6769
6870 nodeKeyECDH := keychain .NewPubKeyECDH (idKeyDesc , cfg .KeyRing )
6971
72+ muxKubKey , err := cfg .KeyRing .DeriveKey (keychain.KeyLocator {})
73+ if err != nil {
74+ return nil , err
75+ }
76+ muxKey , err := common .NewPubKeyFromBytes (
77+ muxKubKey .PubKey .SerializeCompressed (),
78+ )
79+ if err != nil {
80+ return nil , err
81+ }
82+
7083 replayLog := & replayLog {}
7184
7285 sphinxRouter := sphinx .NewRouter (
@@ -88,6 +101,8 @@ func New(cfg *MuxConfig) (*Mux,
88101 settledHandler : cfg .SettledHandler ,
89102 routingPolicy : cfg .RoutingPolicy ,
90103 virtualChannel : virtualChannel ,
104+ muxKey : muxKey ,
105+ nodeKey : cfg .Lnd .PubKey (),
91106 }, nil
92107}
93108
@@ -105,10 +120,11 @@ type interceptedHtlc struct {
105120}
106121
107122type interceptedHtlcResponse struct {
108- action routerrpc.ResolveHoldForwardAction
109- preimage lntypes.Preimage
110- failureMessage []byte
111- failureCode lnrpc.Failure_FailureCode
123+ action routerrpc.ResolveHoldForwardAction
124+ preimage lntypes.Preimage
125+ failureMessage []byte
126+ failureCode lnrpc.Failure_FailureCode
127+ failureMessageUnencrypted bool
112128}
113129
114130func (p * Mux ) Run (mainCtx context.Context ) error {
@@ -221,6 +237,35 @@ func (p *Mux) ProcessHtlc(
221237 fail := func (code lnwire.FailCode ) error {
222238 logger .Debugw ("Failing htlc" , "code" , code )
223239
240+ if code == lnwire .CodeFeeInsufficient {
241+ var channelFlags lnwire.ChanUpdateChanFlags
242+
243+ if bytes .Compare (p .muxKey [:], p .nodeKey [:]) == 1 {
244+ channelFlags |= lnwire .ChanUpdateDirection
245+ }
246+
247+ wireMsg := lnwire .NewFeeInsufficient (0 , lnwire.ChannelUpdate {
248+ ChainHash : * p .lnd .Network ().GenesisHash ,
249+ ShortChannelID : lnwire .NewShortChanIDFromInt (p .virtualChannel ),
250+ Timestamp : uint32 (time .Now ().Unix ()),
251+ ChannelFlags : channelFlags ,
252+ TimeLockDelta : uint16 (p .routingPolicy .CltvDelta ),
253+ BaseFee : uint32 (p .routingPolicy .FeeBaseMsat ),
254+ FeeRate : uint32 (p .routingPolicy .FeeRatePpm ),
255+ })
256+ var w bytes.Buffer
257+ err := lnwire .EncodeFailureMessage (& w , wireMsg , 0 )
258+ if err != nil {
259+ return err
260+ }
261+
262+ return htlc .reply (& interceptedHtlcResponse {
263+ action : routerrpc .ResolveHoldForwardAction_FAIL ,
264+ failureMessage : w .Bytes (),
265+ failureMessageUnencrypted : true ,
266+ })
267+ }
268+
224269 rpcCode , err := marshallFailureCode (code )
225270 if err != nil {
226271 return err
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