Merge pull request #3113 from joostjager/sendtoroute-error-fix

routing: return structured error for send to route

lnrpc/routerrpc/router.pb.go

@@ -566,42 +566,63 @@ func (m *Failure) GetFlags() uint32 {
 }
 
 type ChannelUpdate struct {
-	// Signature is used to validate the announced data and prove the
+	//*
-	// ownership of node id.
+	//The signature that validates the announced data and proves the ownership
+	//of node id.
 	Signature []byte `protobuf:"bytes,1,opt,name=signature,proto3" json:"signature,omitempty"`
-	// ChainHash denotes the target chain that this channel was opened
+	//*
-	// within. This value should be the genesis hash of the target chain.
+	//The target chain that this channel was opened within. This value
-	// Along with the short channel ID, this uniquely identifies the
+	//should be the genesis hash of the target chain. Along with the short
-	// channel globally in a blockchain.
+	//channel ID, this uniquely identifies the channel globally in a
+	//blockchain.
 	ChainHash []byte `protobuf:"bytes,2,opt,name=chain_hash,json=chainHash,proto3" json:"chain_hash,omitempty"`
-	// ShortChannelID is the unique description of the funding transaction.
+	//*
+	//The unique description of the funding transaction.
 	ChanId uint64 `protobuf:"varint,3,opt,name=chan_id,json=chanId,proto3" json:"chan_id,omitempty"`
-	// Timestamp allows ordering in the case of multiple announcements.  We
+	//*
-	// should ignore the message if timestamp is not greater than
+	//A timestamp that allows ordering in the case of multiple announcements.
-	// the last-received.
+	//We should ignore the message if timestamp is not greater than the
+	//last-received.
 	Timestamp uint32 `protobuf:"varint,4,opt,name=timestamp,proto3" json:"timestamp,omitempty"`
-	// Flags is a bitfield that describes additional meta-data concerning
+	//*
-	// how the update is to be interpreted. Currently, the
+	//The bitfield that describes whether optional fields are present in this
-	// least-significant bit must be set to 0 if the creating node
+	//update. Currently, the least-significant bit must be set to 1 if the
-	// corresponds to the first node in the previously sent channel
+	//optional field MaxHtlc is present.
-	// announcement and 1 otherwise. If the second bit is set, then the
+	MessageFlags uint32 `protobuf:"varint,10,opt,name=message_flags,json=messageFlags,proto3" json:"message_flags,omitempty"`
-	// channel is set to be disabled.
+	//*
+	//The bitfield that describes additional meta-data concerning how the
+	//update is to be interpreted. Currently, the least-significant bit must be
+	//set to 0 if the creating node corresponds to the first node in the
+	//previously sent channel announcement and 1 otherwise. If the second bit
+	//is set, then the channel is set to be disabled.
 	ChannelFlags uint32 `protobuf:"varint,5,opt,name=channel_flags,json=channelFlags,proto3" json:"channel_flags,omitempty"`
-	// TimeLockDelta is the minimum number of blocks this node requires to
+	//*
-	// be added to the expiry of HTLCs. This is a security parameter
+	//The minimum number of blocks this node requires to be added to the expiry
-	// determined by the node operator. This value represents the required
+	//of HTLCs. This is a security parameter determined by the node operator.
-	// gap between the time locks of the incoming and outgoing HTLC's set
+	//This value represents the required gap between the time locks of the
-	// to this node.
+	//incoming and outgoing HTLC's set to this node.
 	TimeLockDelta uint32 `protobuf:"varint,6,opt,name=time_lock_delta,json=timeLockDelta,proto3" json:"time_lock_delta,omitempty"`
-	// HtlcMinimumMsat is the minimum HTLC value which will be accepted.
+	//*
+	//The minimum HTLC value which will be accepted.
 	HtlcMinimumMsat uint64 `protobuf:"varint,7,opt,name=htlc_minimum_msat,json=htlcMinimumMsat,proto3" json:"htlc_minimum_msat,omitempty"`
-	// BaseFee is the base fee that must be used for incoming HTLC's to
+	//*
-	// this particular channel. This value will be tacked onto the required
+	//The base fee that must be used for incoming HTLC's to this particular
-	// for a payment independent of the size of the payment.
+	//channel. This value will be tacked onto the required for a payment
+	//independent of the size of the payment.
 	BaseFee uint32 `protobuf:"varint,8,opt,name=base_fee,json=baseFee,proto3" json:"base_fee,omitempty"`
-	// FeeRate is the fee rate that will be charged per millionth of a
+	//*
-	// satoshi.
+	//The fee rate that will be charged per millionth of a satoshi.
 	FeeRate uint32 `protobuf:"varint,9,opt,name=fee_rate,json=feeRate,proto3" json:"fee_rate,omitempty"`
+	//*
+	//The maximum HTLC value which will be accepted.
+	HtlcMaximumMsat uint64 `protobuf:"varint,11,opt,name=htlc_maximum_msat,json=htlcMaximumMsat,proto3" json:"htlc_maximum_msat,omitempty"`
+	//*
+	//The set of data that was appended to this message, some of which we may
+	//not actually know how to iterate or parse. By holding onto this data, we
+	//ensure that we're able to properly validate the set of signatures that
+	//cover these new fields, and ensure we're able to make upgrades to the
+	//network in a forwards compatible manner.
+	ExtraOpaqueData      []byte   `protobuf:"bytes,12,opt,name=extra_opaque_data,json=extraOpaqueData,proto3" json:"extra_opaque_data,omitempty"`
 	XXX_NoUnkeyedLiteral struct{} `json:"-"`
 	XXX_unrecognized     []byte   `json:"-"`
 	XXX_sizecache        int32    `json:"-"`
@@ -660,6 +681,13 @@ func (m *ChannelUpdate) GetTimestamp() uint32 {
 	return 0
 }
 
+func (m *ChannelUpdate) GetMessageFlags() uint32 {
+	if m != nil {
+		return m.MessageFlags
+	}
+	return 0
+}
+
 func (m *ChannelUpdate) GetChannelFlags() uint32 {
 	if m != nil {
 		return m.ChannelFlags
@@ -695,6 +723,20 @@ func (m *ChannelUpdate) GetFeeRate() uint32 {
 	return 0
 }
 
+func (m *ChannelUpdate) GetHtlcMaximumMsat() uint64 {
+	if m != nil {
+		return m.HtlcMaximumMsat
+	}
+	return 0
+}
+
+func (m *ChannelUpdate) GetExtraOpaqueData() []byte {
+	if m != nil {
+		return m.ExtraOpaqueData
+	}
+	return nil
+}
+
 func init() {
 	proto.RegisterEnum("routerrpc.Failure_FailureCode", Failure_FailureCode_name, Failure_FailureCode_value)
 	proto.RegisterType((*PaymentRequest)(nil), "routerrpc.PaymentRequest")
@@ -710,81 +752,84 @@ func init() {
 func init() { proto.RegisterFile("routerrpc/router.proto", fileDescriptor_7a0613f69d37b0a5) }
 
 var fileDescriptor_7a0613f69d37b0a5 = []byte{
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-	0xe8, 0x82, 0xe2, 0x8f, 0x43, 0x8b, 0x5c, 0x1a, 0x1b, 0x8f, 0x19, 0x9c, 0x8f, 0xfa, 0x9d, 0x5c,
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-	0x61, 0x13, 0x1d, 0xc2, 0x81, 0x36, 0xd0, 0x5b, 0xe8, 0xc8, 0x71, 0xa8, 0xeb, 0x38, 0xb6, 0xb1,
+	0xd8, 0x44, 0x07, 0xb0, 0xaf, 0x05, 0x7a, 0x0b, 0x1d, 0xd9, 0x36, 0x75, 0x6c, 0xdb, 0x32, 0xb6,
-	0x85, 0x76, 0xa1, 0x6e, 0xd9, 0x17, 0x66, 0xdf, 0xea, 0x52, 0x82, 0xcd, 0xfe, 0xc0, 0x28, 0xa2,
+	0xd0, 0x0e, 0x54, 0x4d, 0xeb, 0xbc, 0xdd, 0x37, 0xbb, 0x94, 0xe0, 0x76, 0x7f, 0x60, 0xe4, 0xd1,
-	0x3d, 0xd8, 0xb9, 0x6f, 0x57, 0x92, 0x12, 0xb9, 0x9d, 0x63, 0x5b, 0x8e, 0x4d, 0x2f, 0x30, 0x71,
+	0x2e, 0xd4, 0x1e, 0xea, 0x0a, 0xd2, 0x44, 0xa6, 0xb3, 0x2d, 0xd3, 0xb6, 0xe8, 0x39, 0x26, 0x8e,
-	0x2d, 0xc7, 0x36, 0xca, 0xe8, 0x29, 0xa0, 0x75, 0xea, 0x7c, 0x60, 0x76, 0x8c, 0x0a, 0x3a, 0x80,
+	0x69, 0x5b, 0x46, 0x11, 0x3d, 0x05, 0x74, 0x9f, 0x3a, 0x1b, 0xb4, 0x3b, 0x46, 0x09, 0xed, 0xc3,
-	0xdd, 0x75, 0xfc, 0x3d, 0xbe, 0x34, 0x40, 0x86, 0x41, 0x5f, 0x8c, 0xbe, 0xc3, 0x7d, 0xe7, 0x03,
+	0xce, 0x7d, 0xfc, 0x03, 0xbe, 0x30, 0x40, 0xa6, 0x41, 0x1f, 0x8c, 0xbe, 0xc7, 0x7d, 0xfb, 0x23,
-	0x1d, 0x58, 0xb6, 0x35, 0x18, 0x0f, 0x8c, 0x2a, 0xda, 0x07, 0xa3, 0x87, 0x31, 0xb5, 0x6c, 0x77,
+	0x1d, 0x98, 0x96, 0x39, 0x18, 0x0f, 0x8c, 0x32, 0xda, 0x03, 0xa3, 0x87, 0x31, 0x35, 0x2d, 0x67,
-	0xdc, 0xeb, 0x59, 0x1d, 0x0b, 0xdb, 0x23, 0xa3, 0xa6, 0x4f, 0x7e, 0xcc, 0xf1, 0xba, 0xdc, 0xd0,
+	0xdc, 0xeb, 0x99, 0x1d, 0x13, 0x5b, 0x23, 0xa3, 0xa2, 0x3d, 0x3f, 0x16, 0x78, 0x55, 0x6e, 0xe8,
-	0x39, 0x37, 0x6d, 0x1b, 0xf7, 0x69, 0xd7, 0x72, 0xcd, 0x77, 0x7d, 0xdc, 0x35, 0xb6, 0xd1, 0x11,
+	0x9c, 0xb5, 0x2d, 0x0b, 0xf7, 0x69, 0xd7, 0x74, 0xda, 0xef, 0xfb, 0xb8, 0x6b, 0x6c, 0xa3, 0x43,
-	0x1c, 0x8e, 0xf0, 0x60, 0xe8, 0x10, 0x93, 0x5c, 0xd2, 0x9c, 0xef, 0x99, 0x56, 0x7f, 0x4c, 0xb0,
+	0x38, 0x18, 0xe1, 0xc1, 0xd0, 0x26, 0x6d, 0x72, 0x41, 0x33, 0xbe, 0xd7, 0x36, 0xfb, 0x63, 0x82,
-	0xb1, 0x83, 0x5e, 0xc3, 0x11, 0xc1, 0x3f, 0x8d, 0x2d, 0x82, 0xbb, 0xd4, 0x76, 0xba, 0x98, 0xf6,
+	0x8d, 0x1a, 0x7a, 0x0d, 0x87, 0x04, 0xff, 0x3c, 0x36, 0x09, 0xee, 0x52, 0xcb, 0xee, 0x62, 0xda,
-	0xb0, 0x39, 0x1a, 0x13, 0x4c, 0x07, 0x96, 0xeb, 0x5a, 0xf6, 0x8f, 0x86, 0x81, 0xbe, 0x80, 0xe3,
+	0xc3, 0xed, 0xd1, 0x98, 0x60, 0x3a, 0x30, 0x1d, 0xc7, 0xb4, 0x7e, 0x32, 0x0c, 0xf4, 0x15, 0x1c,
-	0xa5, 0xc9, 0x52, 0xe0, 0x9e, 0xd5, 0xae, 0xf4, 0x2f, 0x7f, 0x4f, 0x1b, 0x7f, 0x1c, 0xd1, 0x21,
+	0x2d, 0x25, 0x4b, 0x03, 0x0f, 0x54, 0x3b, 0x32, 0xbe, 0xec, 0x3e, 0x2d, 0xfc, 0x69, 0x44, 0x87,
-	0xc6, 0xc4, 0x40, 0xa8, 0x09, 0x4f, 0xef, 0x8e, 0xd7, 0x07, 0x64, 0x67, 0xef, 0x49, 0x6e, 0x88,
+	0x18, 0x13, 0x03, 0xa1, 0x06, 0x3c, 0x5d, 0xb9, 0xd7, 0x0e, 0x52, 0xdf, 0xbb, 0x92, 0x1b, 0x62,
-	0xc9, 0xc0, 0xb4, 0xe5, 0x03, 0xaf, 0x71, 0xfb, 0xf2, 0xda, 0x77, 0xdc, 0xfd, 0x6b, 0x1f, 0xb4,
+	0x32, 0x68, 0x5b, 0xf2, 0x82, 0xef, 0x71, 0x7b, 0xf2, 0xd8, 0x2b, 0xee, 0xe1, 0xb1, 0xf7, 0x9b,
-	0xfe, 0x7a, 0x02, 0xf5, 0xb5, 0xa4, 0x47, 0x2f, 0xa0, 0x92, 0xfa, 0xd3, 0x90, 0x09, 0x59, 0xca,
+	0x7f, 0x6d, 0x40, 0xf5, 0x5e, 0xd1, 0xa3, 0x17, 0x50, 0x4a, 0xbc, 0x69, 0xc0, 0x84, 0x6c, 0x65,
-	0xba, 0xca, 0xef, 0x00, 0x35, 0x00, 0x66, 0xcc, 0x0f, 0x75, 0x7b, 0xd1, 0xd5, 0x56, 0x51, 0x88,
+	0xdd, 0xe5, 0x2b, 0x40, 0x3d, 0x00, 0x33, 0xe6, 0x05, 0x7a, 0xbc, 0xe8, 0x6e, 0x2b, 0x29, 0x44,
-	0x6a, 0x2e, 0xcf, 0xa0, 0x24, 0x6b, 0x46, 0xf6, 0xf2, 0x0d, 0x55, 0x20, 0x45, 0xb9, 0xb4, 0x3c,
+	0x0d, 0x97, 0x67, 0x50, 0x90, 0x3d, 0x23, 0x67, 0xf9, 0x86, 0x6a, 0x90, 0xbc, 0x5c, 0x9a, 0xae,
-	0xa9, 0x2a, 0xfb, 0x57, 0x2a, 0x58, 0x10, 0xab, 0xda, 0xa9, 0x93, 0x3b, 0x00, 0x7d, 0x0e, 0x79,
+	0xb4, 0x2a, 0xe7, 0x57, 0x22, 0x98, 0x1f, 0xa9, 0xde, 0xa9, 0x92, 0x15, 0x80, 0xbe, 0x84, 0xaa,
-	0xa9, 0x51, 0x9d, 0xff, 0x5b, 0xca, 0xa2, 0x96, 0x81, 0x3d, 0x89, 0x3d, 0xe8, 0x8c, 0x82, 0x65,
+	0xcf, 0x93, 0x84, 0x4d, 0x39, 0xd5, 0xf5, 0x0f, 0x4a, 0x51, 0x49, 0xc1, 0x9e, 0xc4, 0xa4, 0x28,
-	0x15, 0xb4, 0xda, 0x19, 0x05, 0x43, 0x5f, 0xc3, 0xae, 0x2e, 0x53, 0x3f, 0xf4, 0x83, 0x45, 0xa0,
+	0xeb, 0x5f, 0x2d, 0xda, 0xd2, 0xa2, 0x14, 0xd4, 0xa2, 0x87, 0xe3, 0x53, 0xb0, 0xb4, 0xcd, 0xd6,
-	0xcb, 0xb5, 0xa4, 0x6e, 0xb3, 0xa3, 0xca, 0x55, 0xe3, 0xaa, 0x6a, 0x0f, 0xa1, 0x7c, 0xc5, 0x52,
+	0xc7, 0xa7, 0x60, 0xe8, 0x0d, 0xec, 0xe8, 0x5e, 0xf6, 0x02, 0xcf, 0x5f, 0xf8, 0xba, 0xa7, 0x0b,
-	0x2e, 0x9b, 0x72, 0xa3, 0xac, 0xc4, 0x4a, 0x72, 0xdd, 0xe3, 0x6a, 0xbe, 0xc8, 0x56, 0x9d, 0xc8,
+	0xea, 0xc8, 0x35, 0xd5, 0xd3, 0x1a, 0x57, 0xad, 0x7d, 0x00, 0xc5, 0x4b, 0x96, 0x70, 0x39, 0xb9,
-	0x46, 0x51, 0xd1, 0xd4, 0x35, 0xe7, 0x84, 0x09, 0xde, 0xfe, 0xb7, 0x00, 0x45, 0xd5, 0x19, 0x13,
+	0xeb, 0x45, 0x65, 0xac, 0x20, 0xd7, 0x3d, 0xae, 0x1e, 0x21, 0x39, 0xcf, 0x63, 0x39, 0x4d, 0x4a,
-	0xd4, 0x85, 0xaa, 0xec, 0x94, 0xd9, 0x70, 0x42, 0x87, 0x2b, 0xbd, 0x64, 0x7d, 0xee, 0x36, 0x9b,
+	0x9a, 0xba, 0xe2, 0x9c, 0xc8, 0x3c, 0x2e, 0x3d, 0xb0, 0xdb, 0x95, 0x87, 0xf2, 0x9a, 0x07, 0x8d,
-	0x8f, 0x51, 0x59, 0x63, 0x7d, 0x0f, 0x06, 0x4e, 0x85, 0x1f, 0xc8, 0xa6, 0x93, 0x8d, 0x0e, 0xb4,
+	0x2b, 0x0f, 0x6f, 0x60, 0x87, 0xdf, 0x8a, 0x98, 0xd1, 0x30, 0x62, 0x37, 0x0b, 0x4e, 0x5d, 0x26,
-	0x6a, 0x7f, 0x6f, 0x1e, 0x35, 0x9f, 0x3f, 0xca, 0x65, 0x62, 0x7d, 0x7d, 0xa5, 0xac, 0x79, 0xa3,
+	0x58, 0xbd, 0xa2, 0x92, 0x5b, 0x53, 0x84, 0xad, 0xf0, 0x2e, 0x13, 0xac, 0xf5, 0x6f, 0x0e, 0xf2,
-	0xa3, 0x15, 0xdb, 0x87, 0x13, 0xa3, 0xf9, 0xf2, 0xff, 0x68, 0xad, 0xf6, 0xee, 0xdb, 0x9f, 0xcf,
+	0x6a, 0x2c, 0xc7, 0xa8, 0x0b, 0x65, 0x39, 0xa6, 0xd3, 0x97, 0x11, 0x1d, 0xac, 0x0d, 0xb2, 0xfb,
-	0xa6, 0xbe, 0x98, 0x2d, 0xae, 0x4e, 0x27, 0x51, 0x70, 0x36, 0xf7, 0xa7, 0x33, 0x11, 0xfa, 0xe1,
+	0x8f, 0x7e, 0xa3, 0xf1, 0x18, 0x95, 0x4e, 0xf5, 0x0f, 0x60, 0xe0, 0x44, 0x78, 0xbe, 0x9c, 0x78,
-	0x34, 0xe4, 0xe2, 0xf7, 0x28, 0xb9, 0x39, 0x9b, 0x87, 0xde, 0x99, 0x1a, 0x20, 0x67, 0x4b, 0x99,
+	0xe9, 0xbb, 0x85, 0xd6, 0xf5, 0x0f, 0x1e, 0xc3, 0xc6, 0xf3, 0x47, 0xb9, 0xd4, 0x58, 0x5f, 0x1f,
-	0xab, 0xa2, 0xfa, 0xef, 0xf1, 0xdd, 0x7f, 0x01, 0x00, 0x00, 0xff, 0xff, 0x6d, 0x7d, 0x2a, 0xf5,
+	0x29, 0x7d, 0x39, 0xd0, 0xe1, 0x9a, 0xf6, 0xf3, 0xe7, 0xaa, 0xf1, 0xf2, 0xff, 0x68, 0x6d, 0xed,
-	0xab, 0x08, 0x00, 0x00,
+	0xfd, 0x77, 0xbf, 0x9c, 0x4e, 0x3d, 0x31, 0x5b, 0x5c, 0x9e, 0x4c, 0x42, 0xff, 0x74, 0xee, 0x4d,
+	0x67, 0x22, 0xf0, 0x82, 0x69, 0xc0, 0xc5, 0x1f, 0x61, 0x7c, 0x7d, 0x3a, 0x0f, 0xdc, 0x53, 0xf5,
+	0x7a, 0x9d, 0x2e, 0xcd, 0x5c, 0xe6, 0xd5, 0x1f, 0x9f, 0xef, 0xff, 0x0b, 0x00, 0x00, 0xff, 0xff,
+	0x89, 0x21, 0x7b, 0xbd, 0x28, 0x09, 0x00, 0x00,
 }
 
 // Reference imports to suppress errors if they are not otherwise used.

lnrpc/routerrpc/router.proto

@@ -164,50 +164,86 @@ message Failure {
 
 
 message ChannelUpdate {
-	// Signature is used to validate the announced data and prove the
+    /**
-	// ownership of node id.
+    The signature that validates the announced data and proves the ownership
+    of node id.
+    */
     bytes signature = 1;
 
-	// ChainHash denotes the target chain that this channel was opened
+    /**
-	// within. This value should be the genesis hash of the target chain.
+    The target chain that this channel was opened within. This value
-	// Along with the short channel ID, this uniquely identifies the
+    should be the genesis hash of the target chain. Along with the short
-	// channel globally in a blockchain.
+    channel ID, this uniquely identifies the channel globally in a
+    blockchain.
+    */
     bytes chain_hash = 2;
 
-	// ShortChannelID is the unique description of the funding transaction.
+    /**
+    The unique description of the funding transaction.
+    */
     uint64 chan_id = 3;
 
-	// Timestamp allows ordering in the case of multiple announcements.  We
+    /**
-	// should ignore the message if timestamp is not greater than
+    A timestamp that allows ordering in the case of multiple announcements.
-	// the last-received.
+    We should ignore the message if timestamp is not greater than the
+    last-received.
+    */
     uint32 timestamp = 4;
 
-	// Flags is a bitfield that describes additional meta-data concerning
+    /**
-	// how the update is to be interpreted. Currently, the
+    The bitfield that describes whether optional fields are present in this
-	// least-significant bit must be set to 0 if the creating node
+    update. Currently, the least-significant bit must be set to 1 if the
-	// corresponds to the first node in the previously sent channel
+    optional field MaxHtlc is present.
-	// announcement and 1 otherwise. If the second bit is set, then the
+    */
-	// channel is set to be disabled.
+    uint32 message_flags = 10;
+
+    /**
+    The bitfield that describes additional meta-data concerning how the
+    update is to be interpreted. Currently, the least-significant bit must be
+    set to 0 if the creating node corresponds to the first node in the
+    previously sent channel announcement and 1 otherwise. If the second bit
+    is set, then the channel is set to be disabled.
+    */
     uint32 channel_flags = 5;
 
-	// TimeLockDelta is the minimum number of blocks this node requires to
+    /**
-	// be added to the expiry of HTLCs. This is a security parameter
+    The minimum number of blocks this node requires to be added to the expiry
-	// determined by the node operator. This value represents the required
+    of HTLCs. This is a security parameter determined by the node operator.
-	// gap between the time locks of the incoming and outgoing HTLC's set
+    This value represents the required gap between the time locks of the
-	// to this node.
+    incoming and outgoing HTLC's set to this node.
+    */
     uint32 time_lock_delta = 6;
 
-	// HtlcMinimumMsat is the minimum HTLC value which will be accepted.
+    /**
+    The minimum HTLC value which will be accepted.
+    */
     uint64 htlc_minimum_msat = 7;
 
-	// BaseFee is the base fee that must be used for incoming HTLC's to
+    /**
-	// this particular channel. This value will be tacked onto the required
+    The base fee that must be used for incoming HTLC's to this particular
-	// for a payment independent of the size of the payment.
+    channel. This value will be tacked onto the required for a payment
+    independent of the size of the payment.
+    */
     uint32 base_fee = 8;
 
-	// FeeRate is the fee rate that will be charged per millionth of a
+    /**
-	// satoshi.
+    The fee rate that will be charged per millionth of a satoshi.
+    */
     uint32 fee_rate = 9;
+    
+    /**
+    The maximum HTLC value which will be accepted.
+    */
+    uint64 htlc_maximum_msat = 11;
+    
+    /**
+    The set of data that was appended to this message, some of which we may
+    not actually know how to iterate or parse. By holding onto this data, we
+    ensure that we're able to properly validate the set of signatures that
+    cover these new fields, and ensure we're able to make upgrades to the
+    network in a forwards compatible manner.
+    */
+    bytes extra_opaque_data = 12;
 }
 
 service Router {

lnrpc/routerrpc/router_server.go

@@ -429,10 +429,13 @@ func marshallChannelUpdate(update *lnwire.ChannelUpdate) *ChannelUpdate {
 		ChainHash:       update.ChainHash[:],
 		ChanId:          update.ShortChannelID.ToUint64(),
 		Timestamp:       update.Timestamp,
+		MessageFlags:    uint32(update.MessageFlags),
 		ChannelFlags:    uint32(update.ChannelFlags),
 		TimeLockDelta:   uint32(update.TimeLockDelta),
 		HtlcMinimumMsat: uint64(update.HtlcMinimumMsat),
 		BaseFee:         update.BaseFee,
 		FeeRate:         update.FeeRate,
+		HtlcMaximumMsat: uint64(update.HtlcMaximumMsat),
+		ExtraOpaqueData: update.ExtraOpaqueData,
 	}
 }

routing/payment_lifecycle.go

@@ -12,6 +12,20 @@ import (
 	"github.com/lightningnetwork/lnd/routing/route"
 )
 
+// errNoRoute is returned when all routes from the payment session have been
+// attempted.
+type errNoRoute struct {
+	// lastError is the error encountered during the last payment attempt,
+	// if at least one attempt has been made.
+	lastError *htlcswitch.ForwardingError
+}
+
+// Error returns a string representation of the error.
+func (e errNoRoute) Error() string {
+	return fmt.Sprintf("unable to route payment to destination: %v",
+		e.lastError)
+}
+
 // paymentLifecycle holds all information about the current state of a payment
 // needed to resume if from any point.
 type paymentLifecycle struct {
@@ -23,7 +37,7 @@ type paymentLifecycle struct {
 	finalCLTVDelta uint16
 	attempt        *channeldb.PaymentAttemptInfo
 	circuit        *sphinx.Circuit
-	lastError      error
+	lastError      *htlcswitch.ForwardingError
 }
 
 // resumePayment resumes the paymentLifecycle from the current state.
@@ -218,10 +232,8 @@ func (p *paymentLifecycle) createNewPaymentAttempt() (lnwire.ShortChannelID,
 		// payment, we'll return that.
 		if p.lastError != nil {
 			return lnwire.ShortChannelID{}, nil,
-				fmt.Errorf("unable to route payment to "+
+				errNoRoute{lastError: p.lastError}
-					"destination: %v", p.lastError)
 		}
-
 		// Terminal state, return.
 		return lnwire.ShortChannelID{}, nil, err
 	}
@@ -326,10 +338,22 @@ func (p *paymentLifecycle) sendPaymentAttempt(firstHop lnwire.ShortChannelID,
 // handleSendError inspects the given error from the Switch and determines
 // whether we should make another payment attempt.
 func (p *paymentLifecycle) handleSendError(sendErr error) error {
-	finalOutcome := p.router.processSendError(
+	var finalOutcome bool
-		p.paySession, &p.attempt.Route, sendErr,
+
+	// If an internal, non-forwarding error occurred, we can stop trying.
+	fErr, ok := sendErr.(*htlcswitch.ForwardingError)
+	if !ok {
+		finalOutcome = true
+	} else {
+		finalOutcome = p.router.processSendError(
+			p.paySession, &p.attempt.Route, fErr,
 		)
 
+		// Save the forwarding error so it can be returned if this turns
+		// out to be the last attempt.
+		p.lastError = fErr
+	}
+
 	if finalOutcome {
 		log.Errorf("Payment %x failed with final outcome: %v",
 			p.payment.PaymentHash, sendErr)
@@ -348,7 +372,5 @@ func (p *paymentLifecycle) handleSendError(sendErr error) error {
 		return sendErr
 	}
 
-	// We get ready to make another payment attempt.
-	p.lastError = sendErr
 	return nil
 }

routing/router.go

@@ -40,11 +40,6 @@ const (
 )
 
 var (
-	// ErrNoRouteHopsProvided is returned when a caller attempts to
-	// construct a new sphinx packet, but provides an empty set of hops for
-	// each route.
-	ErrNoRouteHopsProvided = fmt.Errorf("empty route hops provided")
-
 	// ErrRouterShuttingDown is returned if the router is in the process of
 	// shutting down.
 	ErrRouterShuttingDown = fmt.Errorf("router shutting down")
@@ -1436,6 +1431,9 @@ func (r *ChannelRouter) FindRoute(source, target route.Vertex,
 		},
 		restrictions, source, target, amt,
 	)
+	if err != nil {
+		return nil, err
+	}
 
 	// We'll fetch the current block height so we can properly calculate the
 	// required HTLC time locks within the route.
@@ -1658,7 +1656,23 @@ func (r *ChannelRouter) SendToRoute(hash lntypes.Hash, route *route.Route) (
 	// Since this is the first time this payment is being made, we pass nil
 	// for the existing attempt.
 	preimage, _, err := r.sendPayment(nil, payment, paySession)
-	return preimage, err
+	if err != nil {
+		// SendToRoute should return a structured error. In case the
+		// provided route fails, payment lifecycle will return a
+		// noRouteError with the structured error embedded.
+		if noRouteError, ok := err.(errNoRoute); ok {
+			if noRouteError.lastError == nil {
+				return lntypes.Preimage{},
+					errors.New("failure message missing")
+			}
+
+			return lntypes.Preimage{}, noRouteError.lastError
+		}
+
+		return lntypes.Preimage{}, err
+	}
+
+	return preimage, nil
 }
 
 // sendPayment attempts to send a payment as described within the passed
@@ -1740,12 +1754,7 @@ func (r *ChannelRouter) sendPayment(
 // to continue with an alternative route. This is indicated by the boolean
 // return value.
 func (r *ChannelRouter) processSendError(paySession PaymentSession,
-	rt *route.Route, err error) bool {
+	rt *route.Route, fErr *htlcswitch.ForwardingError) bool {
-
-	fErr, ok := err.(*htlcswitch.ForwardingError)
-	if !ok {
-		return true
-	}
 
 	errSource := fErr.ErrorSource
 	errVertex := route.NewVertex(errSource)

routing/router_test.go

@@ -3136,3 +3136,107 @@ func TestRouterPaymentStateMachine(t *testing.T) {
 		}
 	}
 }
+
+// TestSendToRouteStructuredError asserts that SendToRoute returns a structured
+// error.
+func TestSendToRouteStructuredError(t *testing.T) {
+	t.Parallel()
+
+	// Setup a three node network.
+	chanCapSat := btcutil.Amount(100000)
+	testChannels := []*testChannel{
+		symmetricTestChannel("a", "b", chanCapSat, &testChannelPolicy{
+			Expiry:  144,
+			FeeRate: 400,
+			MinHTLC: 1,
+			MaxHTLC: lnwire.NewMSatFromSatoshis(chanCapSat),
+		}, 1),
+		symmetricTestChannel("b", "c", chanCapSat, &testChannelPolicy{
+			Expiry:  144,
+			FeeRate: 400,
+			MinHTLC: 1,
+			MaxHTLC: lnwire.NewMSatFromSatoshis(chanCapSat),
+		}, 2),
+	}
+
+	testGraph, err := createTestGraphFromChannels(testChannels)
+	if err != nil {
+		t.Fatalf("unable to create graph: %v", err)
+	}
+	defer testGraph.cleanUp()
+
+	const startingBlockHeight = 101
+
+	ctx, cleanUp, err := createTestCtxFromGraphInstance(
+		startingBlockHeight, testGraph,
+	)
+	if err != nil {
+		t.Fatalf("unable to create router: %v", err)
+	}
+	defer cleanUp()
+
+	// Setup a route from source a to destination c. The route will be used
+	// in a call to SendToRoute. SendToRoute also applies channel updates,
+	// but it saves us from including RequestRoute in the test scope too.
+	hop1 := ctx.aliases["b"]
+	hop2 := ctx.aliases["c"]
+
+	hops := []*route.Hop{
+		{
+			ChannelID:   1,
+			PubKeyBytes: hop1,
+		},
+		{
+			ChannelID:   2,
+			PubKeyBytes: hop2,
+		},
+	}
+
+	rt, err := route.NewRouteFromHops(
+		lnwire.MilliSatoshi(10000), 100,
+		ctx.aliases["a"], hops,
+	)
+	if err != nil {
+		t.Fatalf("unable to create route: %v", err)
+	}
+
+	// We'll modify the SendToSwitch method so that it simulates a failed
+	// payment with an error originating from the first hop of the route.
+	// The unsigned channel update is attached to the failure message.
+	ctx.router.cfg.Payer.(*mockPaymentAttemptDispatcher).setPaymentResult(
+		func(firstHop lnwire.ShortChannelID) ([32]byte, error) {
+
+			v := ctx.aliases["b"]
+			source, err := btcec.ParsePubKey(
+				v[:], btcec.S256(),
+			)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			return [32]byte{}, &htlcswitch.ForwardingError{
+				ErrorSource: source,
+				FailureMessage: &lnwire.FailFeeInsufficient{
+					Update: lnwire.ChannelUpdate{},
+				},
+			}
+		})
+
+	// The payment parameter is mostly redundant in SendToRoute. Can be left
+	// empty for this test.
+	var payment lntypes.Hash
+
+	// Send off the payment request to the router. The specified route
+	// should be attempted and the channel update should be received by
+	// router and ignored because it is missing a valid signature.
+	_, err = ctx.router.SendToRoute(payment, rt)
+
+	fErr, ok := err.(*htlcswitch.ForwardingError)
+	if !ok {
+		t.Fatalf("expected forwarding error")
+	}
+
+	if _, ok := fErr.FailureMessage.(*lnwire.FailFeeInsufficient); !ok {
+		t.Fatalf("expected fee insufficient error")
+	}
+}