packet

package

v1.0.0 Latest Latest Go to latest Published: Dec 6, 2022 License: AGPL-3.0 Imports: 9 Imported by: 0

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Repository

github.com/database64128/opdt-go

Links

Open Source Insights

Documentation ¶

Index ¶

Constants
Variables
func CheckUnixEpochTimestamp(b []byte) error
type Client
- func NewClient(psk []byte) (*Client, error)
- func (c *Client) ParseResponse(resp []byte) (netip.AddrPort, error)
- func (c *Client) PutRequest(req []byte)
type Server
- func NewServer(psk []byte) (*Server, error)
- func (s *Server) Handle(clientAddrPort netip.AddrPort, req []byte, resp []byte) error

Constants ¶

View Source

const (
	MessageTypeRequest = iota
	MessageTypeResponse
)

View Source

const (
	// random nonce + unix epoch timestamp + type + AEAD tag
	RequestPacketSize = chacha20poly1305.NonceSizeX + 8 + 1 + chacha20poly1305.Overhead

	// random nonce + unix epoch timestamp + type + IP + port + AEAD tag
	ResponsePacketSize = chacha20poly1305.NonceSizeX + 8 + 1 + 16 + 2 + chacha20poly1305.Overhead
)

View Source

const (
	// MaxEpochDiff is the maximum allowed time difference between a received timestamp and system time.
	MaxEpochDiff = 30

	// MaxTimeDiff is the maximum allowed time difference between a received timestamp and system time.
	MaxTimeDiff = MaxEpochDiff * time.Second

	// ReplayWindowDuration defines the amount of time during which a nonce check is necessary.
	ReplayWindowDuration = MaxTimeDiff * 2
)

Variables ¶

View Source

var (
	ErrBadPacketSize  = errors.New("bad packet size")
	ErrRepeatedNonce  = errors.New("repeated nonce")
	ErrBadTimestamp   = errors.New("time offset too large")
	ErrBadMessageType = errors.New("bad message type")
)

Functions ¶

func CheckUnixEpochTimestamp ¶

func CheckUnixEpochTimestamp(b []byte) error

CheckUnixEpochTimestamp checks the Unix Epoch timestamp in the buffer and returns an error if the timestamp exceeds the allowed time difference from system time.

This function does not check buffer length. Make sure it's at least 8 bytes long.

Types ¶

type Client ¶

type Client struct {
	// contains filtered or unexported fields
}

Client generates request packets and parses response packets.

func NewClient ¶

func NewClient(psk []byte) (*Client, error)

NewClient creates a new client with the given PSK.

func (*Client) ParseResponse ¶

func (c *Client) ParseResponse(resp []byte) (netip.AddrPort, error)

ParseResponse parses the response packet and returns the client IP and port.

func (*Client) PutRequest ¶

func (c *Client) PutRequest(req []byte)

PutRequest writes a request packet to the first RequestPacketSize bytes of the given buffer.

type Server ¶

type Server struct {
	// contains filtered or unexported fields
}

Server generates responses to request packets.

func NewServer ¶

func NewServer(psk []byte) (*Server, error)

NewServer creates a new server with the given PSK.

func (*Server) Handle ¶

func (s *Server) Handle(clientAddrPort netip.AddrPort, req []byte, resp []byte) error

Handle processes the request packet and writes the response packet to the first ResponsePacketSize bytes of the given buffer.

Source Files ¶

View all Source files

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