lnwire: add ChannelUpdate2

Add the new ChannelUpdate2 message and ensure that it implements the
ChannelUpdate interface.

lnwire/lnwire_test.go

@@ -1590,6 +1590,83 @@ func TestLightningWireProtocol(t *testing.T) {
 				require.NoError(t, err)
 			}
 
+			v[0] = reflect.ValueOf(req)
+		},
+		MsgChannelUpdate2: func(v []reflect.Value, r *rand.Rand) {
+			req := ChannelUpdate2{
+				Signature:       testSchnorrSig,
+				ExtraOpaqueData: make([]byte, 0),
+			}
+
+			req.ShortChannelID.Val = NewShortChanIDFromInt(
+				uint64(r.Int63()),
+			)
+			req.BlockHeight.Val = r.Uint32()
+			req.HTLCMaximumMsat.Val = MilliSatoshi(r.Uint64())
+
+			// Sometimes set chain hash to bitcoin mainnet genesis
+			// hash.
+			req.ChainHash.Val = *chaincfg.MainNetParams.GenesisHash
+			if r.Int31()%2 == 0 {
+				_, err := r.Read(req.ChainHash.Val[:])
+				require.NoError(t, err)
+			}
+
+			// Sometimes use default htlc min msat.
+			req.HTLCMinimumMsat.Val = defaultHtlcMinMsat
+			if r.Int31()%2 == 0 {
+				req.HTLCMinimumMsat.Val = MilliSatoshi(
+					r.Uint64(),
+				)
+			}
+
+			// Sometimes set the cltv expiry delta to the default.
+			req.CLTVExpiryDelta.Val = defaultCltvExpiryDelta
+			if r.Int31()%2 == 0 {
+				req.CLTVExpiryDelta.Val = uint16(r.Int31())
+			}
+
+			// Sometimes use default fee base.
+			req.FeeBaseMsat.Val = defaultFeeBaseMsat
+			if r.Int31()%2 == 0 {
+				req.FeeBaseMsat.Val = r.Uint32()
+			}
+
+			// Sometimes use default proportional fee.
+			req.FeeProportionalMillionths.Val =
+				defaultFeeProportionalMillionths
+			if r.Int31()%2 == 0 {
+				req.FeeProportionalMillionths.Val = r.Uint32()
+			}
+
+			// Alternate between the two direction possibilities.
+			if r.Int31()%2 == 0 {
+				req.SecondPeer = tlv.SomeRecordT(
+					tlv.ZeroRecordT[tlv.TlvType8, TrueBoolean](), //nolint:lll
+				)
+			}
+
+			// Sometimes set the incoming disabled flag.
+			if r.Int31()%2 == 0 {
+				req.DisabledFlags.Val |=
+					ChanUpdateDisableIncoming
+			}
+
+			// Sometimes set the outgoing disabled flag.
+			if r.Int31()%2 == 0 {
+				req.DisabledFlags.Val |=
+					ChanUpdateDisableOutgoing
+			}
+
+			numExtraBytes := r.Int31n(1000)
+			if numExtraBytes > 0 {
+				req.ExtraOpaqueData = make(
+					[]byte, numExtraBytes,
+				)
+				_, err := r.Read(req.ExtraOpaqueData[:])
+				require.NoError(t, err)
+			}
+
 			v[0] = reflect.ValueOf(req)
 		},
 	}
@@ -1832,6 +1909,12 @@ func TestLightningWireProtocol(t *testing.T) {
 				return mainScenario(&m)
 			},
 		},
+		{
+			msgType: MsgChannelUpdate2,
+			scenario: func(m ChannelUpdate2) bool {
+				return mainScenario(&m)
+			},
+		},
 	}
 	for _, test := range tests {
 		var config *quick.Config