package lnwire import ( "bytes" "fmt" "io" "net" "github.com/go-errors/errors" "github.com/roasbeef/btcd/btcec" "github.com/roasbeef/btcd/wire" ) var ( startPort uint16 = 1024 endPort uint16 = 49151 aliasSpecLen = 21 ) // RGB is used to represent the color. type RGB struct { red uint8 green uint8 blue uint8 } // Alias a hex encoded UTF-8 string that may be displayed // as an alternative to the node's ID. Notice that aliases are not // unique and may be freely chosen by the node operators. type Alias [32]byte // NewAlias create the alias from string and also checks spec requirements. func NewAlias(s string) (Alias, error) { var a Alias data := []byte(s) if len(data) > aliasSpecLen { return a, errors.Errorf("alias too long the size "+ "must be less than %v", aliasSpecLen) } copy(a[:], data) return a, nil } func (a *Alias) String() string { return string(a[:]) } // Validate check that alias data lenght is lower than spec size. func (a *Alias) Validate() error { nonzero := len(a) for a[nonzero-1] == 0 && nonzero > 0 { nonzero-- } if nonzero > aliasSpecLen { return errors.New("alias should be less then 21 bytes") } return nil } // NodeAnnouncement message is used to announce the presence of a lightning node // and signal that the node is accepting incoming connections. type NodeAnnouncement struct { // Signature is used to prove the ownership of node id. Signature *btcec.Signature // Timestamp allows ordering in the case of multiple announcements. Timestamp uint32 // Address includes two specification fields: 'ipv6' and 'port' on which // the node is accepting incoming connections. Address *net.TCPAddr // NodeID is a public key which is used as node identification. NodeID *btcec.PublicKey // RGBColor is used to customize their node's appearance in maps and graphs RGBColor RGB // pad is used to reserve to additional bytes for future usage. pad uint16 // Alias is used to customize their node's appearance in maps and graphs Alias Alias } // A compile time check to ensure NodeAnnouncement implements the // lnwire.Message interface. var _ Message = (*NodeAnnouncement)(nil) // Validate performs any necessary sanity checks to ensure all fields present // on the NodeAnnouncement are valid. // // This is part of the lnwire.Message interface. func (a *NodeAnnouncement) Validate() error { if err := a.Alias.Validate(); err != nil { return err } data, err := a.DataToSign() if err != nil { return err } dataHash := wire.DoubleSha256(data) if !a.Signature.Verify(dataHash, a.NodeID) { return errors.New("can't check the node annoucement signature") } return nil } // Decode deserializes a serialized NodeAnnouncement stored in the // passed io.Reader observing the specified protocol version. // // This is part of the lnwire.Message interface. func (c *NodeAnnouncement) Decode(r io.Reader, pver uint32) error { err := readElements(r, &c.Signature, &c.Timestamp, &c.Address, &c.NodeID, &c.RGBColor, &c.pad, &c.Alias, ) if err != nil { return err } return nil } // Encode serializes the target NodeAnnouncement into the passed // io.Writer observing the protocol version specified. // // This is part of the lnwire.Message interface. func (c *NodeAnnouncement) Encode(w io.Writer, pver uint32) error { err := writeElements(w, c.Signature, c.Timestamp, c.Address, c.NodeID, c.RGBColor, c.pad, c.Alias, ) 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 (c *NodeAnnouncement) Command() uint32 { return CmdNodeAnnoucmentMessage } // MaxPayloadLength returns the maximum allowed payload size for this message // observing the specified protocol version. // // This is part of the lnwire.Message interface. func (c *NodeAnnouncement) MaxPayloadLength(pver uint32) uint32 { var length uint32 // Signature - 64 bytes length += 64 // Timestamp - 4 bytes length += 4 // Ipv6 - 16 bytes length += 16 // Port - 4 bytes length += 4 // NodeID - 33 bytes length += 33 // RGBColor - 3 bytes length += 3 // pad - 2 bytes length += 2 // Alias - 32 bytes length += 32 // 158 return length } // String returns the string representation of the target NodeAnnouncement. // // This is part of the lnwire.Message interface. func (c *NodeAnnouncement) String() string { return fmt.Sprintf("\n--- Begin NodeAnnouncement ---\n") + fmt.Sprintf("Signature:\t\t%v\n", c.Signature) + fmt.Sprintf("Timestamp:\t\t%v\n", c.Timestamp) + fmt.Sprintf("Address:\t\t%v\n", c.Address.String()) + fmt.Sprintf("NodeID:\t\t%v\n", c.NodeID) + fmt.Sprintf("RGBColor:\t\t%v\n", c.RGBColor) + fmt.Sprintf("Alias:\t\t%v\n", c.Alias) + fmt.Sprintf("--- End NodeAnnouncement ---\n") } // dataToSign... func (c *NodeAnnouncement) DataToSign() ([]byte, error) { // We should not include the signatures itself. var w bytes.Buffer err := writeElements(&w, c.Timestamp, c.Address, c.NodeID, c.RGBColor, c.pad, c.Alias, ) if err != nil { return nil, err } return w.Bytes(), nil }