lnd.xprv/lnwire/init_message.go

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package lnwire
import (
"io"
"github.com/go-errors/errors"
)
// Init is the first message reveals the features supported or required by this
// node. Nodes wait for receipt of the other's features to simplify error
// diagnosis where features are incompatible. Each node MUST wait to receive
// init before sending any other messages.
type Init struct {
// GlobalFeatures is feature vector which affects HTLCs and thus are
// also advertised to other nodes.
GlobalFeatures *FeatureVector
// LocalFeatures is feature vector which only affect the protocol
// between two nodes.
LocalFeatures *FeatureVector
}
// NewInitMessage creates new instance of init message object.
func NewInitMessage(gf, lf *FeatureVector) *Init {
return &Init{
GlobalFeatures: gf,
LocalFeatures: lf,
}
}
// Decode deserializes a serialized Init message stored in the passed
// io.Reader observing the specified protocol version.
//
// This is part of the lnwire.Message interface.
func (msg *Init) Decode(r io.Reader, pver uint32) error {
// LocalFeatures(~)
// GlobalFeatures(~)
err := readElements(r,
&msg.LocalFeatures,
&msg.GlobalFeatures,
)
if err != nil {
return err
}
return nil
}
// A compile time check to ensure Init implements the lnwire.Message
// interface.
var _ Message = (*Init)(nil)
// Encode serializes the target Init into the passed io.Writer observing
// the protocol version specified.
//
// This is part of the lnwire.Message interface.
func (msg *Init) Encode(w io.Writer, pver uint32) error {
err := writeElements(w,
msg.LocalFeatures,
msg.GlobalFeatures,
)
if err != nil {
return err
}
return nil
}
// Command returns the integer uniquely identifying this message type on the
// wire.
//
// This is part of the lnwire.Message interface.
func (msg *Init) Command() uint32 {
return CmdInit
}
// MaxPayloadLength returns the maximum allowed payload size for a Init
// complete message observing the specified protocol version.
//
// This is part of the lnwire.Message interface.
func (msg *Init) MaxPayloadLength(uint32) uint32 {
return 2 + maxAllowedSize + 2 + maxAllowedSize
}
// Validate performs any necessary sanity checks to ensure all fields present
// on the Init are valid.
//
// This is part of the lnwire.Message interface.
func (msg *Init) Validate() error {
if msg.GlobalFeatures.serializedSize() > maxAllowedSize {
return errors.Errorf("global feature vector exceed max allowed "+
"size %v", maxAllowedSize)
}
if msg.LocalFeatures.serializedSize() > maxAllowedSize {
return errors.Errorf("local feature vector exceed max allowed "+
"size %v", maxAllowedSize)
}
return nil
}