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115 lines
3.4 KiB
Go
115 lines
3.4 KiB
Go
package wtwire
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import (
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"fmt"
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"io"
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"github.com/btcsuite/btcd/chaincfg/chainhash"
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"github.com/lightningnetwork/lnd/feature"
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"github.com/lightningnetwork/lnd/lnwire"
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)
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// Init is the first message sent over the watchtower wire protocol, and
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// specifies connection features bits and level of requiredness maintained by
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// the sending node. The Init message also sends the chain hash identifying the
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// network that the sender is on.
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type Init struct {
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// ConnFeatures are the feature bits being advertised for the duration
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// of a single connection with a peer.
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ConnFeatures *lnwire.RawFeatureVector
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// ChainHash is the genesis hash of the chain that the advertiser claims
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// to be on.
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ChainHash chainhash.Hash
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}
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// NewInitMessage generates a new Init message from a raw connection feature
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// vector and chain hash.
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func NewInitMessage(connFeatures *lnwire.RawFeatureVector,
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chainHash chainhash.Hash) *Init {
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return &Init{
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ConnFeatures: connFeatures,
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ChainHash: chainHash,
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}
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}
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// Encode serializes the target Init into the passed io.Writer observing the
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// protocol version specified.
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//
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// This is part of the wtwire.Message interface.
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func (msg *Init) Encode(w io.Writer, pver uint32) error {
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return WriteElements(w,
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msg.ConnFeatures,
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msg.ChainHash,
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)
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}
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// Decode deserializes a serialized Init message stored in the passed io.Reader
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// observing the specified protocol version.
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//
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// This is part of the wtwire.Message interface.
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func (msg *Init) Decode(r io.Reader, pver uint32) error {
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return ReadElements(r,
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&msg.ConnFeatures,
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&msg.ChainHash,
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)
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}
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// MsgType returns the integer uniquely identifying this message type on the
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// wire.
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//
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// This is part of the wtwire.Message interface.
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func (msg *Init) MsgType() MessageType {
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return MsgInit
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}
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// MaxPayloadLength returns the maximum allowed payload size for an Init
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// complete message observing the specified protocol version.
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//
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// This is part of the wtwire.Message interface.
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func (msg *Init) MaxPayloadLength(uint32) uint32 {
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return MaxMessagePayload
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}
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// A compile-time constraint to ensure Init implements the Message interface.
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var _ Message = (*Init)(nil)
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// CheckRemoteInit performs basic validation of the remote party's Init message.
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// This method checks that the remote Init's chain hash matches our advertised
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// chain hash and that the remote Init does not contain any required feature
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// bits that we don't understand.
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func (msg *Init) CheckRemoteInit(remoteInit *Init,
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featureNames map[lnwire.FeatureBit]string) error {
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// Check that the remote peer is on the same chain.
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if msg.ChainHash != remoteInit.ChainHash {
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return NewErrUnknownChainHash(remoteInit.ChainHash)
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}
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remoteConnFeatures := lnwire.NewFeatureVector(
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remoteInit.ConnFeatures, featureNames,
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)
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// Check that the remote peer doesn't have any required connection
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// feature bits that we ourselves are unaware of.
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return feature.ValidateRequired(remoteConnFeatures)
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}
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// ErrUnknownChainHash signals that the remote Init has a different chain hash
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// from the one we advertised.
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type ErrUnknownChainHash struct {
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hash chainhash.Hash
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}
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// NewErrUnknownChainHash creates an ErrUnknownChainHash using the remote Init's
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// chain hash.
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func NewErrUnknownChainHash(hash chainhash.Hash) *ErrUnknownChainHash {
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return &ErrUnknownChainHash{hash}
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}
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// Error returns a human-readable error displaying the unknown chain hash.
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func (e *ErrUnknownChainHash) Error() string {
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return fmt.Sprintf("remote init has unknown chain hash: %s", e.hash)
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}
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