16171981582

Committed 09 Jul 2025 02:22PM UTC coverage: 55.32% (-2.3%) from 57.62%

Build # 16171981582

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Pull #10059

github

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web-flow

Commit Message

Merge b62793ada into ea32aac77

Pull Request Pull Request #10059: .gemini: add styleguide.md

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81.3

/lnwire/onion_error.go

package lnwire

import (
        "bufio"
        "bytes"
        "crypto/sha256"
        "encoding/binary"
        "fmt"
        "io"

        "github.com/davecgh/go-spew/spew"
        "github.com/lightningnetwork/lnd/fn/v2"
        "github.com/lightningnetwork/lnd/tlv"
)

// FailureMessage represents the onion failure object identified by its unique
// failure code.
type FailureMessage interface {
        // Code returns a failure code describing the exact nature of the
        // error.
        Code() FailCode

        // Error returns a human readable string describing the error. With
        // this method, the FailureMessage interface meets the built-in error
        // interface.
        Error() string
}

// FailureMessageLength is the size of the failure message plus the size of
// padding. The FailureMessage message should always be EXACTLY this size.
const FailureMessageLength = 256

const (
        // FlagBadOnion error flag describes an unparsable, encrypted by
        // previous node.
        FlagBadOnion FailCode = 0x8000

        // FlagPerm error flag indicates a permanent failure.
        FlagPerm FailCode = 0x4000

        // FlagNode error flag indicates a node failure.
        FlagNode FailCode = 0x2000

        // FlagUpdate error flag indicates a new channel update is enclosed
        // within the error.
        FlagUpdate FailCode = 0x1000
)

// FailCode specifies the precise reason that an upstream HTLC was canceled.
// Each UpdateFailHTLC message carries a FailCode which is to be passed
// backwards, encrypted at each step back to the source of the HTLC within the
// route.
type FailCode uint16

// The currently defined onion failure types within this current version of the
// Lightning protocol.
const (
        CodeNone                             FailCode = 0
        CodeInvalidRealm                              = FlagBadOnion | 1
        CodeTemporaryNodeFailure                      = FlagNode | 2
        CodePermanentNodeFailure                      = FlagPerm | FlagNode | 2
        CodeRequiredNodeFeatureMissing                = FlagPerm | FlagNode | 3
        CodeInvalidOnionVersion                       = FlagBadOnion | FlagPerm | 4
        CodeInvalidOnionHmac                          = FlagBadOnion | FlagPerm | 5
        CodeInvalidOnionKey                           = FlagBadOnion | FlagPerm | 6
        CodeTemporaryChannelFailure                   = FlagUpdate | 7
        CodePermanentChannelFailure                   = FlagPerm | 8
        CodeRequiredChannelFeatureMissing             = FlagPerm | 9
        CodeUnknownNextPeer                           = FlagPerm | 10
        CodeAmountBelowMinimum                        = FlagUpdate | 11
        CodeFeeInsufficient                           = FlagUpdate | 12
        CodeIncorrectCltvExpiry                       = FlagUpdate | 13
        CodeExpiryTooSoon                             = FlagUpdate | 14
        CodeChannelDisabled                           = FlagUpdate | 20
        CodeIncorrectOrUnknownPaymentDetails          = FlagPerm | 15
        CodeIncorrectPaymentAmount                    = FlagPerm | 16
        CodeFinalExpiryTooSoon               FailCode = 17
        CodeFinalIncorrectCltvExpiry         FailCode = 18
        CodeFinalIncorrectHtlcAmount         FailCode = 19
        CodeExpiryTooFar                     FailCode = 21
        CodeInvalidOnionPayload                       = FlagPerm | 22
        CodeMPPTimeout                       FailCode = 23
        CodeInvalidBlinding                           = FlagBadOnion | FlagPerm | 24 //nolint:ll
)

// String returns the string representation of the failure code.
func (c FailCode) String() string {
        switch c {
        case CodeInvalidRealm:
                return "InvalidRealm"

        case CodeTemporaryNodeFailure:
                return "TemporaryNodeFailure"

        case CodePermanentNodeFailure:
                return "PermanentNodeFailure"

        case CodeRequiredNodeFeatureMissing:
                return "RequiredNodeFeatureMissing"

        case CodeInvalidOnionVersion:
                return "InvalidOnionVersion"

        case CodeInvalidOnionHmac:
                return "InvalidOnionHmac"

        case CodeInvalidOnionKey:
                return "InvalidOnionKey"

        case CodeTemporaryChannelFailure:
                return "TemporaryChannelFailure"

        case CodePermanentChannelFailure:
                return "PermanentChannelFailure"

        case CodeRequiredChannelFeatureMissing:
                return "RequiredChannelFeatureMissing"

        case CodeUnknownNextPeer:
                return "UnknownNextPeer"

        case CodeAmountBelowMinimum:
                return "AmountBelowMinimum"

        case CodeFeeInsufficient:
                return "FeeInsufficient"

        case CodeIncorrectCltvExpiry:
                return "IncorrectCltvExpiry"

        case CodeIncorrectPaymentAmount:
                return "IncorrectPaymentAmount"

        case CodeExpiryTooSoon:
                return "ExpiryTooSoon"

        case CodeChannelDisabled:
                return "ChannelDisabled"

        case CodeIncorrectOrUnknownPaymentDetails:
                return "IncorrectOrUnknownPaymentDetails"

        case CodeFinalExpiryTooSoon:
                return "FinalExpiryTooSoon"

        case CodeFinalIncorrectCltvExpiry:
                return "FinalIncorrectCltvExpiry"

        case CodeFinalIncorrectHtlcAmount:
                return "FinalIncorrectHtlcAmount"

        case CodeExpiryTooFar:
                return "ExpiryTooFar"

        case CodeInvalidOnionPayload:
                return "InvalidOnionPayload"

        case CodeMPPTimeout:
                return "MPPTimeout"

        case CodeInvalidBlinding:
                return "InvalidBlinding"

        default:
                return "<unknown>"
        }
}

// FailInvalidRealm is returned if the realm byte is unknown.
//
// NOTE: May be returned by any node in the payment route.
type FailInvalidRealm struct{}

// Returns a human readable string describing the target FailureMessage.
//
// NOTE: Implements the error interface.
func (f *FailInvalidRealm) Error() string {
        return f.Code().String()
}

// Code returns the failure unique code.
//
// NOTE: Part of the FailureMessage interface.
func (f *FailInvalidRealm) Code() FailCode {
        return CodeInvalidRealm
}

// FailTemporaryNodeFailure is returned if an otherwise unspecified transient
// error occurs for the entire node.
//
// NOTE: May be returned by any node in the payment route.
type FailTemporaryNodeFailure struct{}

// Code returns the failure unique code.
// NOTE: Part of the FailureMessage interface.
func (f *FailTemporaryNodeFailure) Code() FailCode {
        return CodeTemporaryNodeFailure
}

// Returns a human readable string describing the target FailureMessage.
//
// NOTE: Implements the error interface.
func (f *FailTemporaryNodeFailure) Error() string {
        return f.Code().String()
}

// FailPermanentNodeFailure is returned if an otherwise unspecified permanent
// error occurs for the entire node.
//
// NOTE: May be returned by any node in the payment route.
type FailPermanentNodeFailure struct{}

// Code returns the failure unique code.
//
// NOTE: Part of the FailureMessage interface.
func (f *FailPermanentNodeFailure) Code() FailCode {
        return CodePermanentNodeFailure
}

// Returns a human readable string describing the target FailureMessage.
//
// NOTE: Implements the error interface.
func (f *FailPermanentNodeFailure) Error() string {
        return f.Code().String()
}

// FailRequiredNodeFeatureMissing is returned if a node has requirement
// advertised in its node_announcement features which were not present in the
// onion.
//
// NOTE: May be returned by any node in the payment route.
type FailRequiredNodeFeatureMissing struct{}

// Code returns the failure unique code.
//
// NOTE: Part of the FailureMessage interface.
func (f *FailRequiredNodeFeatureMissing) Code() FailCode {
        return CodeRequiredNodeFeatureMissing
}

// Returns a human readable string describing the target FailureMessage.
//
// NOTE: Implements the error interface.
func (f *FailRequiredNodeFeatureMissing) Error() string {
        return f.Code().String()
}

// FailPermanentChannelFailure is return if an otherwise unspecified permanent
// error occurs for the outgoing channel (eg. channel (recently).
//
// NOTE: May be returned by any node in the payment route.
type FailPermanentChannelFailure struct{}

// Code returns the failure unique code.
//
// NOTE: Part of the FailureMessage interface.
func (f *FailPermanentChannelFailure) Code() FailCode {
        return CodePermanentChannelFailure
}

// Returns a human readable string describing the target FailureMessage.
//
// NOTE: Implements the error interface.
func (f *FailPermanentChannelFailure) Error() string {
        return f.Code().String()
}

// FailRequiredChannelFeatureMissing is returned if the outgoing channel has a
// requirement advertised in its channel announcement features which were not
// present in the onion.
//
// NOTE: May only be returned by intermediate nodes.
type FailRequiredChannelFeatureMissing struct{}

// Code returns the failure unique code.
//
// NOTE: Part of the FailureMessage interface.
func (f *FailRequiredChannelFeatureMissing) Code() FailCode {
        return CodeRequiredChannelFeatureMissing
}

// Returns a human readable string describing the target FailureMessage.
//
// NOTE: Implements the error interface.
func (f *FailRequiredChannelFeatureMissing) Error() string {
        return f.Code().String()
}

// FailUnknownNextPeer is returned if the next peer specified by the onion is
// not known.
//
// NOTE: May only be returned by intermediate nodes.
type FailUnknownNextPeer struct{}

// Code returns the failure unique code.
//
// NOTE: Part of the FailureMessage interface.
func (f *FailUnknownNextPeer) Code() FailCode {
        return CodeUnknownNextPeer
}

// Returns a human readable string describing the target FailureMessage.
//
// NOTE: Implements the error interface.
func (f *FailUnknownNextPeer) Error() string {
        return f.Code().String()
}

// FailIncorrectPaymentAmount is returned if the amount paid is less than the
// amount expected, the final node MUST fail the HTLC. If the amount paid is
// more than twice the amount expected, the final node SHOULD fail the HTLC.
// This allows the sender to reduce information leakage by altering the amount,
// without allowing accidental gross overpayment.
//
// NOTE: May only be returned by the final node in the path.
type FailIncorrectPaymentAmount struct{}

// Code returns the failure unique code.
//
// NOTE: Part of the FailureMessage interface.
func (f *FailIncorrectPaymentAmount) Code() FailCode {
        return CodeIncorrectPaymentAmount
}

// Returns a human readable string describing the target FailureMessage.
//
// NOTE: Implements the error interface.
func (f *FailIncorrectPaymentAmount) Error() string {
        return f.Code().String()
}

// FailIncorrectDetails is returned for two reasons:
//
// 1) if the payment hash has already been paid, the final node MAY treat the
// payment hash as unknown, or may succeed in accepting the HTLC. If the
// payment hash is unknown, the final node MUST fail the HTLC.
//
// 2) if the amount paid is less than the amount expected, the final node MUST
// fail the HTLC. If the amount paid is more than twice the amount expected,
// the final node SHOULD fail the HTLC. This allows the sender to reduce
// information leakage by altering the amount, without allowing accidental
// gross overpayment.
//
// NOTE: May only be returned by the final node in the path.
type FailIncorrectDetails struct {
        // amount is the value of the extended HTLC.
        amount MilliSatoshi

        // height is the block height when the htlc was received.
        height uint32

        // extraOpaqueData contains additional failure message tlv data.
        extraOpaqueData ExtraOpaqueData
}

// NewFailIncorrectDetails makes a new instance of the FailIncorrectDetails
// error bound to the specified HTLC amount and acceptance height.
func NewFailIncorrectDetails(amt MilliSatoshi,
        height uint32) *FailIncorrectDetails {

        return &FailIncorrectDetails{
                amount:          amt,
                height:          height,
                extraOpaqueData: []byte{},
        }
}

// Amount is the value of the extended HTLC.
func (f *FailIncorrectDetails) Amount() MilliSatoshi {
        return f.amount
}

// Height is the block height when the htlc was received.
func (f *FailIncorrectDetails) Height() uint32 {
        return f.height
}

// ExtraOpaqueData returns additional failure message tlv data.
func (f *FailIncorrectDetails) ExtraOpaqueData() ExtraOpaqueData {
        return f.extraOpaqueData
}

// Code returns the failure unique code.
//
// NOTE: Part of the FailureMessage interface.
func (f *FailIncorrectDetails) Code() FailCode {
        return CodeIncorrectOrUnknownPaymentDetails
}

// Returns a human readable string describing the target FailureMessage.
//
// NOTE: Implements the error interface.
func (f *FailIncorrectDetails) Error() string {
        return fmt.Sprintf(
                "%v(amt=%v, height=%v)", CodeIncorrectOrUnknownPaymentDetails,
                f.amount, f.height,
        )
}

// Decode decodes the failure from bytes stream.
//
// NOTE: Part of the Serializable interface.
func (f *FailIncorrectDetails) Decode(r io.Reader, pver uint32) error {
        err := ReadElement(r, &f.amount)
        switch {
        // This is an optional tack on that was added later in the protocol. As
        // a result, older nodes may not include this value. We'll account for
        // this by checking for io.EOF here which means that no bytes were read
        // at all.
        case err == io.EOF:
                return nil

        case err != nil:
                return err
        }

        // At a later stage, the height field was also tacked on. We need to
        // check for io.EOF here as well.
        err = ReadElement(r, &f.height)
        switch {
        case err == io.EOF:
                return nil

        case err != nil:
                return err
        }

        return f.extraOpaqueData.Decode(r)
}

// Encode writes the failure in bytes stream.
//
// NOTE: Part of the Serializable interface.
func (f *FailIncorrectDetails) Encode(w *bytes.Buffer, pver uint32) error {
        if err := WriteMilliSatoshi(w, f.amount); err != nil {
                return err
        }

        if err := WriteUint32(w, f.height); err != nil {
                return err
        }

        return f.extraOpaqueData.Encode(w)
}

// FailFinalExpiryTooSoon is returned if the cltv_expiry is too low, the final
// node MUST fail the HTLC.
//
// NOTE: May only be returned by the final node in the path.
type FailFinalExpiryTooSoon struct{}

// Code returns the failure unique code.
//
// NOTE: Part of the FailureMessage interface.
func (f *FailFinalExpiryTooSoon) Code() FailCode {
        return CodeFinalExpiryTooSoon
}

// Returns a human readable string describing the target FailureMessage.
//
// NOTE: Implements the error interface.
func (f *FailFinalExpiryTooSoon) Error() string {
        return f.Code().String()
}

// NewFinalExpiryTooSoon creates new instance of the FailFinalExpiryTooSoon.
func NewFinalExpiryTooSoon() *FailFinalExpiryTooSoon {
        return &FailFinalExpiryTooSoon{}
}

// FailInvalidOnionVersion is returned if the onion version byte is unknown.
//
// NOTE: May be returned only by intermediate nodes.
type FailInvalidOnionVersion struct {
        // OnionSHA256 hash of the onion blob which haven't been proceeded.
        OnionSHA256 [sha256.Size]byte
}

// Returns a human readable string describing the target FailureMessage.
//
// NOTE: Implements the error interface.
func (f *FailInvalidOnionVersion) Error() string {
        return fmt.Sprintf("InvalidOnionVersion(onion_sha=%x)", f.OnionSHA256[:])
}

// NewInvalidOnionVersion creates new instance of the FailInvalidOnionVersion.
func NewInvalidOnionVersion(onion []byte) *FailInvalidOnionVersion {
        return &FailInvalidOnionVersion{OnionSHA256: sha256.Sum256(onion)}
}

// Code returns the failure unique code.
//
// NOTE: Part of the FailureMessage interface.
func (f *FailInvalidOnionVersion) Code() FailCode {
        return CodeInvalidOnionVersion
}

// Decode decodes the failure from bytes stream.
//
// NOTE: Part of the Serializable interface.
func (f *FailInvalidOnionVersion) Decode(r io.Reader, pver uint32) error {
        return ReadElement(r, f.OnionSHA256[:])
}

// Encode writes the failure in bytes stream.
//
// NOTE: Part of the Serializable interface.
func (f *FailInvalidOnionVersion) Encode(w *bytes.Buffer, pver uint32) error {
        return WriteBytes(w, f.OnionSHA256[:])
}

// FailInvalidOnionHmac is return if the onion HMAC is incorrect.
//
// NOTE: May only be returned by intermediate nodes.
type FailInvalidOnionHmac struct {
        // OnionSHA256 hash of the onion blob which haven't been proceeded.
        OnionSHA256 [sha256.Size]byte
}

// NewInvalidOnionHmac creates new instance of the FailInvalidOnionHmac.
func NewInvalidOnionHmac(onion []byte) *FailInvalidOnionHmac {
        return &FailInvalidOnionHmac{OnionSHA256: sha256.Sum256(onion)}
}

// Code returns the failure unique code.
//
// NOTE: Part of the FailureMessage interface.
func (f *FailInvalidOnionHmac) Code() FailCode {
        return CodeInvalidOnionHmac
}

// Decode decodes the failure from bytes stream.
//
// NOTE: Part of the Serializable interface.
func (f *FailInvalidOnionHmac) Decode(r io.Reader, pver uint32) error {
        return ReadElement(r, f.OnionSHA256[:])
}

// Encode writes the failure in bytes stream.
//
// NOTE: Part of the Serializable interface.
func (f *FailInvalidOnionHmac) Encode(w *bytes.Buffer, pver uint32) error {
        return WriteBytes(w, f.OnionSHA256[:])
}

// Returns a human readable string describing the target FailureMessage.
//
// NOTE: Implements the error interface.
func (f *FailInvalidOnionHmac) Error() string {
        return fmt.Sprintf("InvalidOnionHMAC(onion_sha=%x)", f.OnionSHA256[:])
}

// FailInvalidOnionKey is return if the ephemeral key in the onion is
// unparsable.
//
// NOTE: May only be returned by intermediate nodes.
type FailInvalidOnionKey struct {
        // OnionSHA256 hash of the onion blob which haven't been proceeded.
        OnionSHA256 [sha256.Size]byte
}

// NewInvalidOnionKey creates new instance of the FailInvalidOnionKey.
func NewInvalidOnionKey(onion []byte) *FailInvalidOnionKey {
        return &FailInvalidOnionKey{OnionSHA256: sha256.Sum256(onion)}
}

// Code returns the failure unique code.
//
// NOTE: Part of the FailureMessage interface.
func (f *FailInvalidOnionKey) Code() FailCode {
        return CodeInvalidOnionKey
}

// Decode decodes the failure from bytes stream.
//
// NOTE: Part of the Serializable interface.
func (f *FailInvalidOnionKey) Decode(r io.Reader, pver uint32) error {
        return ReadElement(r, f.OnionSHA256[:])
}

// Encode writes the failure in bytes stream.
//
// NOTE: Part of the Serializable interface.
func (f *FailInvalidOnionKey) Encode(w *bytes.Buffer, pver uint32) error {
        return WriteBytes(w, f.OnionSHA256[:])
}

// Returns a human readable string describing the target FailureMessage.
//
// NOTE: Implements the error interface.
func (f *FailInvalidOnionKey) Error() string {
        return fmt.Sprintf("InvalidOnionKey(onion_sha=%x)", f.OnionSHA256[:])
}

// parseChannelUpdateCompatibilityMode will attempt to parse a channel updated
// encoded into an onion error payload in two ways. First, we'll try the
// compatibility oriented version wherein we'll _skip_ the length prefixing on
// the channel update message. Older versions of c-lighting do this so we'll
// attempt to parse these messages in order to retain compatibility. If we're
// unable to pull out a fully valid version, then we'll fall back to the
// regular parsing mechanism which includes the length prefix an NO type byte.
func parseChannelUpdateCompatibilityMode(reader io.Reader, length uint16,
        chanUpdate *ChannelUpdate1, pver uint32) error {

        // Instantiate a LimitReader because there may be additional data
        // present after the channel update. Without limiting the stream, the
        // additional data would be interpreted as channel update tlv data.
        limitReader := io.LimitReader(reader, int64(length))

        r := bufio.NewReader(limitReader)

        // We'll peek out two bytes from the buffer without advancing the
        // buffer so we can decide how to parse the remainder of it.
        maybeTypeBytes, err := r.Peek(2)
        if err != nil {
                return err
        }

        // Some nodes well prefix an additional set of bytes in front of their
        // channel updates. These bytes will _almost_ always be 258 or the type
        // of the ChannelUpdate message.
        typeInt := binary.BigEndian.Uint16(maybeTypeBytes)
        if typeInt == MsgChannelUpdate {
                // At this point it's likely the case that this is a channel
                // update message with its type prefixed, so we'll snip off the
                // first two bytes and parse it as normal.
                var throwAwayTypeBytes [2]byte
                _, err := r.Read(throwAwayTypeBytes[:])
                if err != nil {
                        return err
                }
        }

        // At this pint, we've either decided to keep the entire thing, or snip
        // off the first two bytes. In either case, we can just read it as
        // normal.
        return chanUpdate.Decode(r, pver)
}

// FailTemporaryChannelFailure is if an otherwise unspecified transient error
// occurs for the outgoing channel (eg. channel capacity reached, too many
// in-flight htlcs)
//
// NOTE: May only be returned by intermediate nodes.
type FailTemporaryChannelFailure struct {
        // Update is used to update information about state of the channel
        // which caused the failure.
        //
        // NOTE: This field is optional.
        Update *ChannelUpdate1
}

// NewTemporaryChannelFailure creates new instance of the FailTemporaryChannelFailure.
func NewTemporaryChannelFailure(
        update *ChannelUpdate1) *FailTemporaryChannelFailure {

        return &FailTemporaryChannelFailure{Update: update}
}

// Code returns the failure unique code.
//
// NOTE: Part of the FailureMessage interface.
func (f *FailTemporaryChannelFailure) Code() FailCode {
        return CodeTemporaryChannelFailure
}

// Returns a human readable string describing the target FailureMessage.
//
// NOTE: Implements the error interface.
func (f *FailTemporaryChannelFailure) Error() string {
        if f.Update == nil {
                return f.Code().String()
        }

        return fmt.Sprintf("TemporaryChannelFailure(update=%v)",
                spew.Sdump(f.Update))
}

// Decode decodes the failure from bytes stream.
//
// NOTE: Part of the Serializable interface.
func (f *FailTemporaryChannelFailure) Decode(r io.Reader, pver uint32) error {
        var length uint16
        err := ReadElement(r, &length)
        if err != nil {
                return err
        }

        if length != 0 {
                f.Update = &ChannelUpdate1{}

                return parseChannelUpdateCompatibilityMode(
                        r, length, f.Update, pver,
                )
        }

        return nil
}

// Encode writes the failure in bytes stream.
//
// NOTE: Part of the Serializable interface.
func (f *FailTemporaryChannelFailure) Encode(w *bytes.Buffer,
        pver uint32) error {

        if f.Update != nil {
                return writeOnionErrorChanUpdate(w, f.Update, pver)
        }

        // Write zero length to indicate no channel_update is present.
        return WriteUint16(w, 0)
}

// FailAmountBelowMinimum is returned if the HTLC does not reach the current
// minimum amount, we tell them the amount of the incoming HTLC and the current
// channel setting for the outgoing channel.
//
// NOTE: May only be returned by the intermediate nodes in the path.
type FailAmountBelowMinimum struct {
        // HtlcMsat is the wrong amount of the incoming HTLC.
        HtlcMsat MilliSatoshi

        // Update is used to update information about state of the channel
        // which caused the failure.
        Update ChannelUpdate1
}

// NewAmountBelowMinimum creates new instance of the FailAmountBelowMinimum.
func NewAmountBelowMinimum(htlcMsat MilliSatoshi,
        update ChannelUpdate1) *FailAmountBelowMinimum {

        return &FailAmountBelowMinimum{
                HtlcMsat: htlcMsat,
                Update:   update,
        }
}

// Code returns the failure unique code.
//
// NOTE: Part of the FailureMessage interface.
func (f *FailAmountBelowMinimum) Code() FailCode {
        return CodeAmountBelowMinimum
}

// Returns a human readable string describing the target FailureMessage.
//
// NOTE: Implements the error interface.
func (f *FailAmountBelowMinimum) Error() string {
        return fmt.Sprintf("AmountBelowMinimum(amt=%v, update=%v", f.HtlcMsat,
                spew.Sdump(f.Update))
}

// Decode decodes the failure from bytes stream.
//
// NOTE: Part of the Serializable interface.
func (f *FailAmountBelowMinimum) Decode(r io.Reader, pver uint32) error {
        if err := ReadElement(r, &f.HtlcMsat); err != nil {
                return err
        }

        var length uint16
        if err := ReadElement(r, &length); err != nil {
                return err
        }

        f.Update = ChannelUpdate1{}

        return parseChannelUpdateCompatibilityMode(
                r, length, &f.Update, pver,
        )
}

// Encode writes the failure in bytes stream.
//
// NOTE: Part of the Serializable interface.
func (f *FailAmountBelowMinimum) Encode(w *bytes.Buffer, pver uint32) error {
        if err := WriteMilliSatoshi(w, f.HtlcMsat); err != nil {
                return err
        }

        return writeOnionErrorChanUpdate(w, &f.Update, pver)
}

// FailFeeInsufficient is returned if the HTLC does not pay sufficient fee, we
// tell them the amount of the incoming HTLC and the current channel setting
// for the outgoing channel.
//
// NOTE: May only be returned by intermediate nodes.
type FailFeeInsufficient struct {
        // HtlcMsat is the wrong amount of the incoming HTLC.
        HtlcMsat MilliSatoshi

        // Update is used to update information about state of the channel
        // which caused the failure.
        Update ChannelUpdate1
}

// NewFeeInsufficient creates new instance of the FailFeeInsufficient.
func NewFeeInsufficient(htlcMsat MilliSatoshi,
        update ChannelUpdate1) *FailFeeInsufficient {
        return &FailFeeInsufficient{
                HtlcMsat: htlcMsat,
                Update:   update,
        }
}

// Code returns the failure unique code.
//
// NOTE: Part of the FailureMessage interface.
func (f *FailFeeInsufficient) Code() FailCode {
        return CodeFeeInsufficient
}

// Returns a human readable string describing the target FailureMessage.
//
// NOTE: Implements the error interface.
func (f *FailFeeInsufficient) Error() string {
        return fmt.Sprintf("FeeInsufficient(htlc_amt==%v, update=%v", f.HtlcMsat,
                spew.Sdump(f.Update))
}

// Decode decodes the failure from bytes stream.
//
// NOTE: Part of the Serializable interface.
func (f *FailFeeInsufficient) Decode(r io.Reader, pver uint32) error {
        if err := ReadElement(r, &f.HtlcMsat); err != nil {
                return err
        }

        var length uint16
        if err := ReadElement(r, &length); err != nil {
                return err
        }

        f.Update = ChannelUpdate1{}

        return parseChannelUpdateCompatibilityMode(
                r, length, &f.Update, pver,
        )
}

// Encode writes the failure in bytes stream.
//
// NOTE: Part of the Serializable interface.
func (f *FailFeeInsufficient) Encode(w *bytes.Buffer, pver uint32) error {
        if err := WriteMilliSatoshi(w, f.HtlcMsat); err != nil {
                return err
        }

        return writeOnionErrorChanUpdate(w, &f.Update, pver)
}

// FailIncorrectCltvExpiry is returned if outgoing cltv value does not match
// the update add htlc's cltv expiry minus cltv expiry delta for the outgoing
// channel, we tell them the cltv expiry and the current channel setting for
// the outgoing channel.
//
// NOTE: May only be returned by intermediate nodes.
type FailIncorrectCltvExpiry struct {
        // CltvExpiry is the wrong absolute timeout in blocks, after which
        // outgoing HTLC expires.
        CltvExpiry uint32

        // Update is used to update information about state of the channel
        // which caused the failure.
        Update ChannelUpdate1
}

// NewIncorrectCltvExpiry creates new instance of the FailIncorrectCltvExpiry.
func NewIncorrectCltvExpiry(cltvExpiry uint32,
        update ChannelUpdate1) *FailIncorrectCltvExpiry {

        return &FailIncorrectCltvExpiry{
                CltvExpiry: cltvExpiry,
                Update:     update,
        }
}

// Code returns the failure unique code.
//
// NOTE: Part of the FailureMessage interface.
func (f *FailIncorrectCltvExpiry) Code() FailCode {
        return CodeIncorrectCltvExpiry
}

func (f *FailIncorrectCltvExpiry) Error() string {
        return fmt.Sprintf("IncorrectCltvExpiry(expiry=%v, update=%v",
                f.CltvExpiry, spew.Sdump(f.Update))
}

// Decode decodes the failure from bytes stream.
//
// NOTE: Part of the Serializable interface.
func (f *FailIncorrectCltvExpiry) Decode(r io.Reader, pver uint32) error {
        if err := ReadElement(r, &f.CltvExpiry); err != nil {
                return err
        }

        var length uint16
        if err := ReadElement(r, &length); err != nil {
                return err
        }

        f.Update = ChannelUpdate1{}

        return parseChannelUpdateCompatibilityMode(
                r, length, &f.Update, pver,
        )
}

// Encode writes the failure in bytes stream.
//
// NOTE: Part of the Serializable interface.
func (f *FailIncorrectCltvExpiry) Encode(w *bytes.Buffer, pver uint32) error {
        if err := WriteUint32(w, f.CltvExpiry); err != nil {
                return err
        }

        return writeOnionErrorChanUpdate(w, &f.Update, pver)
}

// FailExpiryTooSoon is returned if the ctlv-expiry is too near, we tell them
// the current channel setting for the outgoing channel.
//
// NOTE: May only be returned by intermediate nodes.
type FailExpiryTooSoon struct {
        // Update is used to update information about state of the channel
        // which caused the failure.
        Update ChannelUpdate1
}

// NewExpiryTooSoon creates new instance of the FailExpiryTooSoon.
func NewExpiryTooSoon(update ChannelUpdate1) *FailExpiryTooSoon {
        return &FailExpiryTooSoon{
                Update: update,
        }
}

// Code returns the failure unique code.
//
// NOTE: Part of the FailureMessage interface.
func (f *FailExpiryTooSoon) Code() FailCode {
        return CodeExpiryTooSoon
}

// Returns a human readable string describing the target FailureMessage.
//
// NOTE: Implements the error interface.
func (f *FailExpiryTooSoon) Error() string {
        return fmt.Sprintf("ExpiryTooSoon(update=%v", spew.Sdump(f.Update))
}

// Decode decodes the failure from l stream.
//
// NOTE: Part of the Serializable interface.
func (f *FailExpiryTooSoon) Decode(r io.Reader, pver uint32) error {
        var length uint16
        if err := ReadElement(r, &length); err != nil {
                return err
        }

        f.Update = ChannelUpdate1{}

        return parseChannelUpdateCompatibilityMode(
                r, length, &f.Update, pver,
        )
}

// Encode writes the failure in bytes stream.
//
// NOTE: Part of the Serializable interface.
func (f *FailExpiryTooSoon) Encode(w *bytes.Buffer, pver uint32) error {
        return writeOnionErrorChanUpdate(w, &f.Update, pver)
}

// FailChannelDisabled is returned if the channel is disabled, we tell them the
// current channel setting for the outgoing channel.
//
// NOTE: May only be returned by intermediate nodes.
type FailChannelDisabled struct {
        // Flags 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.
        Flags uint16

        // Update is used to update information about state of the channel
        // which caused the failure.
        Update ChannelUpdate1
}

// NewChannelDisabled creates new instance of the FailChannelDisabled.
func NewChannelDisabled(flags uint16,
        update ChannelUpdate1) *FailChannelDisabled {

        return &FailChannelDisabled{
                Flags:  flags,
                Update: update,
        }
}

// Code returns the failure unique code.
//
// NOTE: Part of the FailureMessage interface.
func (f *FailChannelDisabled) Code() FailCode {
        return CodeChannelDisabled
}

// Returns a human readable string describing the target FailureMessage.
//
// NOTE: Implements the error interface.
func (f *FailChannelDisabled) Error() string {
        return fmt.Sprintf("ChannelDisabled(flags=%v, update=%v", f.Flags,
                spew.Sdump(f.Update))
}

// Decode decodes the failure from bytes stream.
//
// NOTE: Part of the Serializable interface.
func (f *FailChannelDisabled) Decode(r io.Reader, pver uint32) error {
        if err := ReadElement(r, &f.Flags); err != nil {
                return err
        }

        var length uint16
        if err := ReadElement(r, &length); err != nil {
                return err
        }

        f.Update = ChannelUpdate1{}

        return parseChannelUpdateCompatibilityMode(
                r, length, &f.Update, pver,
        )
}

// Encode writes the failure in bytes stream.
//
// NOTE: Part of the Serializable interface.
func (f *FailChannelDisabled) Encode(w *bytes.Buffer, pver uint32) error {
        if err := WriteUint16(w, f.Flags); err != nil {
                return err
        }

        return writeOnionErrorChanUpdate(w, &f.Update, pver)
}

// FailFinalIncorrectCltvExpiry is returned if the outgoing_cltv_value does not
// match the ctlv_expiry of the HTLC at the final hop.
//
// NOTE: might be returned by final node only.
type FailFinalIncorrectCltvExpiry struct {
        // CltvExpiry is the wrong absolute timeout in blocks, after which
        // outgoing HTLC expires.
        CltvExpiry uint32
}

// Returns a human readable string describing the target FailureMessage.
//
// NOTE: Implements the error interface.
func (f *FailFinalIncorrectCltvExpiry) Error() string {
        return fmt.Sprintf("FinalIncorrectCltvExpiry(expiry=%v)", f.CltvExpiry)
}

// NewFinalIncorrectCltvExpiry creates new instance of the
// FailFinalIncorrectCltvExpiry.
func NewFinalIncorrectCltvExpiry(cltvExpiry uint32) *FailFinalIncorrectCltvExpiry {
        return &FailFinalIncorrectCltvExpiry{
                CltvExpiry: cltvExpiry,
        }
}

// Code returns the failure unique code.
//
// NOTE: Part of the FailureMessage interface.
func (f *FailFinalIncorrectCltvExpiry) Code() FailCode {
        return CodeFinalIncorrectCltvExpiry
}

// Decode decodes the failure from bytes stream.
//
// NOTE: Part of the Serializable interface.
func (f *FailFinalIncorrectCltvExpiry) Decode(r io.Reader, pver uint32) error {
        return ReadElement(r, &f.CltvExpiry)
}

// Encode writes the failure in bytes stream.
//
// NOTE: Part of the Serializable interface.
func (f *FailFinalIncorrectCltvExpiry) Encode(w *bytes.Buffer,
        pver uint32) error {

        return WriteUint32(w, f.CltvExpiry)
}

// FailFinalIncorrectHtlcAmount is returned if the amt_to_forward is higher
// than incoming_htlc_amt of the HTLC at the final hop.
//
// NOTE: May only be returned by the final node.
type FailFinalIncorrectHtlcAmount struct {
        // IncomingHTLCAmount is the wrong forwarded htlc amount.
        IncomingHTLCAmount MilliSatoshi
}

// Returns a human readable string describing the target FailureMessage.
//
// NOTE: Implements the error interface.
func (f *FailFinalIncorrectHtlcAmount) Error() string {
        return fmt.Sprintf("FinalIncorrectHtlcAmount(amt=%v)",
                f.IncomingHTLCAmount)
}

// NewFinalIncorrectHtlcAmount creates new instance of the
// FailFinalIncorrectHtlcAmount.
func NewFinalIncorrectHtlcAmount(amount MilliSatoshi) *FailFinalIncorrectHtlcAmount {
        return &FailFinalIncorrectHtlcAmount{
                IncomingHTLCAmount: amount,
        }
}

// Code returns the failure unique code.
//
// NOTE: Part of the FailureMessage interface.
func (f *FailFinalIncorrectHtlcAmount) Code() FailCode {
        return CodeFinalIncorrectHtlcAmount
}

// Decode decodes the failure from bytes stream.
//
// NOTE: Part of the Serializable interface.
func (f *FailFinalIncorrectHtlcAmount) Decode(r io.Reader, pver uint32) error {
        return ReadElement(r, &f.IncomingHTLCAmount)
}

// Encode writes the failure in bytes stream.
//
// NOTE: Part of the Serializable interface.
func (f *FailFinalIncorrectHtlcAmount) Encode(w *bytes.Buffer,
        pver uint32) error {

        return WriteMilliSatoshi(w, f.IncomingHTLCAmount)
}

// FailExpiryTooFar is returned if the CLTV expiry in the HTLC is too far in the
// future.
//
// NOTE: May be returned by any node in the payment route.
type FailExpiryTooFar struct{}

// Code returns the failure unique code.
//
// NOTE: Part of the FailureMessage interface.
func (f *FailExpiryTooFar) Code() FailCode {
        return CodeExpiryTooFar
}

// Returns a human readable string describing the target FailureMessage.
//
// NOTE: Implements the error interface.
func (f *FailExpiryTooFar) Error() string {
        return f.Code().String()
}

// InvalidOnionPayload is returned if the hop could not process the TLV payload
// enclosed in the onion.
type InvalidOnionPayload struct {
        // Type is the TLV type that caused the specific failure.
        Type uint64

        // Offset is the byte offset within the payload where the failure
        // occurred.
        Offset uint16
}

// NewInvalidOnionPayload initializes a new InvalidOnionPayload failure.
func NewInvalidOnionPayload(typ uint64, offset uint16) *InvalidOnionPayload {
        return &InvalidOnionPayload{
                Type:   typ,
                Offset: offset,
        }
}

// Code returns the failure unique code.
//
// NOTE: Part of the FailureMessage interface.
func (f *InvalidOnionPayload) Code() FailCode {
        return CodeInvalidOnionPayload
}

// Returns a human readable string describing the target FailureMessage.
//
// NOTE: Implements the error interface.
func (f *InvalidOnionPayload) Error() string {
        return fmt.Sprintf("%v(type=%v, offset=%d)",
                f.Code(), f.Type, f.Offset)
}

// Decode decodes the failure from bytes stream.
//
// NOTE: Part of the Serializable interface.
func (f *InvalidOnionPayload) Decode(r io.Reader, pver uint32) error {
        var buf [8]byte
        typ, err := tlv.ReadVarInt(r, &buf)
        if err != nil {
                return err
        }
        f.Type = typ

        return ReadElements(r, &f.Offset)
}

// Encode writes the failure in bytes stream.
//
// NOTE: Part of the Serializable interface.
func (f *InvalidOnionPayload) Encode(w *bytes.Buffer, pver uint32) error {
        var buf [8]byte
        if err := tlv.WriteVarInt(w, f.Type, &buf); err != nil {
                return err
        }

        return WriteUint16(w, f.Offset)
}

// FailMPPTimeout is returned if the complete amount for a multi part payment
// was not received within a reasonable time.
//
// NOTE: May only be returned by the final node in the path.
type FailMPPTimeout struct{}

// Code returns the failure unique code.
//
// NOTE: Part of the FailureMessage interface.
func (f *FailMPPTimeout) Code() FailCode {
        return CodeMPPTimeout
}

// Returns a human readable string describing the target FailureMessage.
//
// NOTE: Implements the error interface.
func (f *FailMPPTimeout) Error() string {
        return f.Code().String()
}

// FailInvalidBlinding is returned if there has been a route blinding related
// error.
type FailInvalidBlinding struct {
        OnionSHA256 [sha256.Size]byte
}

// Code returns the failure unique code.
//
// NOTE: Part of the FailureMessage interface.
func (f *FailInvalidBlinding) Code() FailCode {
        return CodeInvalidBlinding
}

// Returns a human readable string describing the target FailureMessage.
//
// NOTE: Implements the error interface.
func (f *FailInvalidBlinding) Error() string {
        return f.Code().String()
}

// Decode decodes the failure from bytes stream.
//
// NOTE: Part of the Serializable interface.
func (f *FailInvalidBlinding) Decode(r io.Reader, _ uint32) error {
        return ReadElement(r, f.OnionSHA256[:])
}

// Encode writes the failure in bytes stream.
//
// NOTE: Part of the Serializable interface.
func (f *FailInvalidBlinding) Encode(w *bytes.Buffer, _ uint32) error {
        return WriteBytes(w, f.OnionSHA256[:])
}

// NewInvalidBlinding creates new instance of FailInvalidBlinding.
func NewInvalidBlinding(
        onion fn.Option[[OnionPacketSize]byte]) *FailInvalidBlinding {
        // The spec allows empty onion hashes for invalid blinding, so we only
        // include our onion hash if it's provided.
        if onion.IsNone() {
                return &FailInvalidBlinding{}
        }

        shaSum := fn.MapOptionZ(onion, func(o [OnionPacketSize]byte) [32]byte {
                return sha256.Sum256(o[:])
        })

        return &FailInvalidBlinding{OnionSHA256: shaSum}
}

// DecodeFailure decodes, validates, and parses the lnwire onion failure, for
// the provided protocol version.
func DecodeFailure(r io.Reader, pver uint32) (FailureMessage, error) {
        // First, we'll parse out the encapsulated failure message itself. This
        // is a 2 byte length followed by the payload itself.
        var failureLength uint16
        if err := ReadElement(r, &failureLength); err != nil {
                return nil, fmt.Errorf("unable to read failure len: %w", err)
        }

        failureData := make([]byte, failureLength)
        if _, err := io.ReadFull(r, failureData); err != nil {
                return nil, fmt.Errorf("unable to full read payload of "+
                        "%v: %w", failureLength, err)
        }

        // Read the padding.
        var padLength uint16
        if err := ReadElement(r, &padLength); err != nil {
                return nil, fmt.Errorf("unable to read pad len: %w", err)
        }

        if _, err := io.CopyN(io.Discard, r, int64(padLength)); err != nil {
                return nil, fmt.Errorf("unable to read padding %w", err)
        }

        // Verify that we are at the end of the stream now.
        scratch := make([]byte, 1)
        _, err := r.Read(scratch)
        if err != io.EOF {
                return nil, fmt.Errorf("unexpected failure bytes")
        }

        // Check the total length. Convert to 32 bits to prevent overflow.
        totalLength := uint32(padLength) + uint32(failureLength)
        if totalLength < FailureMessageLength {
                return nil, fmt.Errorf("failure message too short: "+
                        "msg=%v, pad=%v, total=%v",
                        failureLength, padLength, totalLength)
        }

        // Decode the failure message.
        dataReader := bytes.NewReader(failureData)

        return DecodeFailureMessage(dataReader, pver)
}

// DecodeFailureMessage decodes just the failure message, ignoring any padding
// that may be present at the end.
func DecodeFailureMessage(r io.Reader, pver uint32) (FailureMessage, error) {
        // Once we have the failure data, we can obtain the failure code from
        // the first two bytes of the buffer.
        var codeBytes [2]byte
        if _, err := io.ReadFull(r, codeBytes[:]); err != nil {
                return nil, fmt.Errorf("unable to read failure code: %w", err)
        }
        failCode := FailCode(binary.BigEndian.Uint16(codeBytes[:]))

        // Create the empty failure by given code and populate the failure with
        // additional data if needed.
        failure, err := makeEmptyOnionError(failCode)
        if err != nil {
                return nil, fmt.Errorf("unable to make empty error: %w", err)
        }

        // Finally, if this failure has a payload, then we'll read that now as
        // well.
        switch f := failure.(type) {
        case Serializable:
                if err := f.Decode(r, pver); err != nil {
                        return nil, fmt.Errorf("unable to decode error "+
                                "update (type=%T): %v", failure, err)
                }
        }

        return failure, nil
}

// EncodeFailure encodes, including the necessary onion failure header
// information.
func EncodeFailure(w *bytes.Buffer, failure FailureMessage, pver uint32) error {
        var failureMessageBuffer bytes.Buffer

        err := EncodeFailureMessage(&failureMessageBuffer, failure, pver)
        if err != nil {
                return err
        }

        // The combined size of this message must be below the max allowed
        // failure message length.
        failureMessage := failureMessageBuffer.Bytes()
        if len(failureMessage) > FailureMessageLength {
                return fmt.Errorf("failure message exceed max "+
                        "available size: %v", len(failureMessage))
        }

        // Finally, we'll add some padding in order to ensure that all failure
        // messages are fixed size.
        pad := make([]byte, FailureMessageLength-len(failureMessage))

        if err := WriteUint16(w, uint16(len(failureMessage))); err != nil {
                return err
        }

        if err := WriteBytes(w, failureMessage); err != nil {
                return err
        }
        if err := WriteUint16(w, uint16(len(pad))); err != nil {
                return err
        }

        return WriteBytes(w, pad)
}

// EncodeFailureMessage encodes just the failure message without adding a length
// and padding the message for the onion protocol.
func EncodeFailureMessage(w *bytes.Buffer,
        failure FailureMessage, pver uint32) error {

        // First, we'll write out the error code itself into the failure
        // buffer.
        var codeBytes [2]byte
        code := uint16(failure.Code())
        binary.BigEndian.PutUint16(codeBytes[:], code)
        _, err := w.Write(codeBytes[:])
        if err != nil {
                return err
        }

        // Next, some message have an additional message payload, if this is
        // one of those types, then we'll also encode the error payload as
        // well.
        switch failure := failure.(type) {
        case Serializable:
                if err := failure.Encode(w, pver); err != nil {
                        return err
                }
        }

        return nil
}

// makeEmptyOnionError creates a new empty onion error  of the proper concrete
// type based on the passed failure code.
func makeEmptyOnionError(code FailCode) (FailureMessage, error) {
        switch code {
        case CodeInvalidRealm:
                return &FailInvalidRealm{}, nil

        case CodeTemporaryNodeFailure:
                return &FailTemporaryNodeFailure{}, nil

        case CodePermanentNodeFailure:
                return &FailPermanentNodeFailure{}, nil

        case CodeRequiredNodeFeatureMissing:
                return &FailRequiredNodeFeatureMissing{}, nil

        case CodePermanentChannelFailure:
                return &FailPermanentChannelFailure{}, nil

        case CodeRequiredChannelFeatureMissing:
                return &FailRequiredChannelFeatureMissing{}, nil

        case CodeUnknownNextPeer:
                return &FailUnknownNextPeer{}, nil

        case CodeIncorrectOrUnknownPaymentDetails:
                return &FailIncorrectDetails{}, nil

        case CodeIncorrectPaymentAmount:
                return &FailIncorrectPaymentAmount{}, nil

        case CodeFinalExpiryTooSoon:
                return &FailFinalExpiryTooSoon{}, nil

        case CodeInvalidOnionVersion:
                return &FailInvalidOnionVersion{}, nil

        case CodeInvalidOnionHmac:
                return &FailInvalidOnionHmac{}, nil

        case CodeInvalidOnionKey:
                return &FailInvalidOnionKey{}, nil

        case CodeTemporaryChannelFailure:
                return &FailTemporaryChannelFailure{}, nil

        case CodeAmountBelowMinimum:
                return &FailAmountBelowMinimum{}, nil

        case CodeFeeInsufficient:
                return &FailFeeInsufficient{}, nil

        case CodeIncorrectCltvExpiry:
                return &FailIncorrectCltvExpiry{}, nil

        case CodeExpiryTooSoon:
                return &FailExpiryTooSoon{}, nil

        case CodeChannelDisabled:
                return &FailChannelDisabled{}, nil

        case CodeFinalIncorrectCltvExpiry:
                return &FailFinalIncorrectCltvExpiry{}, nil

        case CodeFinalIncorrectHtlcAmount:
                return &FailFinalIncorrectHtlcAmount{}, nil

        case CodeExpiryTooFar:
                return &FailExpiryTooFar{}, nil

        case CodeInvalidOnionPayload:
                return &InvalidOnionPayload{}, nil

        case CodeMPPTimeout:
                return &FailMPPTimeout{}, nil

        case CodeInvalidBlinding:
                return &FailInvalidBlinding{}, nil

        default:
                return nil, fmt.Errorf("unknown error code: %v", code)
        }
}

// writeOnionErrorChanUpdate writes out a ChannelUpdate using the onion error
// format. The format is that we first write out the true serialized length of
// the channel update, followed by the serialized channel update itself.
func writeOnionErrorChanUpdate(w *bytes.Buffer, chanUpdate *ChannelUpdate1,
        pver uint32) error {

        // First, we encode the channel update in a temporary buffer in order
        // to get the exact serialized size.
        var b bytes.Buffer
        updateLen, err := WriteMessage(&b, chanUpdate, pver)
        if err != nil {
                return err
        }

        // Now that we know the size, we can write the length out in the main
        // writer.
        if err := WriteUint16(w, uint16(updateLen)); err != nil {
                return err
        }

        // With the length written, we'll then write out the serialized channel
        // update.
        if _, err := w.Write(b.Bytes()); err != nil {
                return err
        }

        return nil
}

lightningnetwork / lnd / 16171981582

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