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Copy pathclient.go
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417 lines (358 loc) · 10.9 KB
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package netcode
import (
"log"
"net"
"time"
)
const CLIENT_MAX_RECEIVE_PACKETS = 64
const PACKET_SEND_RATE = 10.0
const NUM_DISCONNECT_PACKETS = 10 // number of disconnect packets the client/server should send when disconnecting
type Context struct {
WritePacketKey []byte
ReadPacketKey []byte
}
type ClientState int8
const (
StateTokenExpired ClientState = -6
StateInvalidConnectToken = -5
StateConnectionTimedOut = -4
StateConnectionResponseTimedOut = -3
StateConnectionRequestTimedOut = -2
StateConnectionDenied = -1
StateDisconnected = 0
StateSendingConnectionRequest = 1
StateSendingConnectionResponse = 2
StateConnected = 3
)
var clientStateMap = map[ClientState]string{
StateTokenExpired: "connect token expired",
StateInvalidConnectToken: "invalid connect token",
StateConnectionTimedOut: "connection timed out",
StateConnectionResponseTimedOut: "connection response timed out",
StateConnectionRequestTimedOut: "connection request timed out",
StateConnectionDenied: "connection denied",
StateDisconnected: "disconnected",
StateSendingConnectionRequest: "sending connection request",
StateSendingConnectionResponse: "sending connection response",
StateConnected: "connected",
}
type Client struct {
id uint64
connectToken *ConnectToken
time float64
startTime float64
lastPacketSendTime float64
lastPacketRecvTime float64
shouldDisconnect bool
state ClientState
shouldDisconnectState ClientState
sequence uint64
challengeSequence uint64
clientIndex uint32
maxClients uint32
serverIndex int
address *net.UDPAddr
serverAddress *net.UDPAddr
challengeData []byte
context *Context
replayProtection *ReplayProtection
conn *NetcodeConn
packetQueue *PacketQueue
allowedPackets []byte
packetCh chan *NetcodeData
}
func NewClient(connectToken *ConnectToken) *Client {
c := &Client{connectToken: connectToken}
c.lastPacketRecvTime = -1
c.lastPacketSendTime = -1
c.packetCh = make(chan *NetcodeData, PACKET_QUEUE_SIZE)
c.setState(StateDisconnected)
c.shouldDisconnect = false
c.challengeData = make([]byte, CHALLENGE_TOKEN_BYTES)
c.context = &Context{}
c.packetQueue = NewPacketQueue(PACKET_QUEUE_SIZE)
c.replayProtection = NewReplayProtection()
c.allowedPackets = make([]byte, ConnectionNumPackets)
c.allowedPackets[ConnectionDenied] = 1
c.allowedPackets[ConnectionChallenge] = 1
c.allowedPackets[ConnectionKeepAlive] = 1
c.allowedPackets[ConnectionPayload] = 1
c.allowedPackets[ConnectionDisconnect] = 1
return c
}
func (c *Client) GetState() ClientState {
return c.state
}
func (c *Client) SetId(id uint64) {
c.id = id
}
func (c *Client) setState(newState ClientState) {
c.state = newState
}
func (c *Client) Connect() error {
var err error
c.startTime = 0
if c.serverIndex > len(c.connectToken.ServerAddrs) {
return ErrExceededServerNumber
}
c.serverAddress = &c.connectToken.ServerAddrs[c.serverIndex]
c.conn = NewNetcodeConn()
c.conn.SetRecvHandler(c.handleNetcodeData)
if err = c.conn.Dial(c.serverAddress); err != nil {
return err
}
c.context.ReadPacketKey = c.connectToken.ServerKey
c.context.WritePacketKey = c.connectToken.ClientKey
c.setState(StateSendingConnectionRequest)
return nil
}
func (c *Client) connectNextServer() bool {
if c.serverIndex+1 >= len(c.connectToken.ServerAddrs) {
return false
}
c.serverIndex++
c.serverAddress = &c.connectToken.ServerAddrs[c.serverIndex]
c.Reset()
log.Printf("client[%d] connecting to next server %s (%d/%d)\n", c.id, c.serverAddress.String(), c.serverIndex, len(c.connectToken.ServerAddrs))
if err := c.Connect(); err != nil {
log.Printf("error connecting to next server: %s\n", err)
return false
}
c.setState(StateSendingConnectionRequest)
return true
}
func (c *Client) Close() error {
return c.conn.Close()
}
func (c *Client) Reset() {
c.lastPacketSendTime = c.time - 1
c.lastPacketRecvTime = c.time
c.shouldDisconnect = false
c.shouldDisconnectState = StateDisconnected
c.challengeData = make([]byte, CHALLENGE_TOKEN_BYTES)
c.challengeSequence = 0
c.replayProtection.Reset()
}
func (c *Client) resetConnectionData(newState ClientState) {
c.sequence = 0
c.clientIndex = 0
c.maxClients = 0
c.startTime = 0
c.serverIndex = 0
c.serverAddress = nil
c.connectToken = nil
c.context = nil
c.setState(newState)
c.Reset()
c.packetQueue.Clear()
c.conn.Close()
}
func (c *Client) LocalAddr() net.Addr {
return c.conn.LocalAddr()
}
func (c *Client) RemoteAddr() net.Addr {
return c.conn.RemoteAddr()
}
func (c *Client) Update(t float64) {
c.time = t
c.recv()
if err := c.send(); err != nil {
log.Printf("error sending packet: %s\n", err)
}
state := c.GetState()
if state > StateDisconnected && state < StateConnected {
expire := c.connectToken.ExpireTimestamp - c.connectToken.CreateTimestamp
if c.startTime+float64(expire) <= c.time {
log.Printf("client[%d] connect failed. connect token expired\n", c.id)
c.Disconnect(StateTokenExpired, false)
return
}
}
if c.shouldDisconnect {
log.Printf("client[%d] should disconnect -> %s\n", c.id, clientStateMap[c.shouldDisconnectState])
if c.connectNextServer() {
return
}
c.Disconnect(c.shouldDisconnectState, false)
return
}
switch c.GetState() {
case StateSendingConnectionRequest:
timeout := c.lastPacketRecvTime + float64(c.connectToken.TimeoutSeconds*1000)
if timeout < c.time {
log.Printf("client[%d] connection request timed out.\n", c.id)
if c.connectNextServer() {
return
}
c.Disconnect(StateConnectionRequestTimedOut, false)
}
case StateSendingConnectionResponse:
timeout := c.lastPacketRecvTime + float64(c.connectToken.TimeoutSeconds*1000)
if timeout < c.time {
log.Printf("client[%d] connect failed. connection response timed out\n", c.id)
if c.connectNextServer() {
return
}
c.Disconnect(StateConnectionResponseTimedOut, false)
}
case StateConnected:
timeout := c.lastPacketRecvTime + float64(c.connectToken.TimeoutSeconds*1000)
if timeout < c.time {
log.Printf("client[%d] connection timed out\n", c.id)
c.Disconnect(StateConnectionTimedOut, false)
}
}
}
func (c *Client) recv() {
// empty recv'd data from channel
for {
select {
case recv := <-c.packetCh:
c.OnPacketData(recv.data, recv.from)
default:
return
}
}
}
func (c *Client) Disconnect(reason ClientState, sendDisconnect bool) error {
log.Printf("client[%d] disconnected: %s\n", c.id, clientStateMap[reason])
if c.GetState() <= StateDisconnected {
log.Printf("state <= StateDisconnected")
return nil
}
if sendDisconnect && c.GetState() > StateDisconnected {
for i := 0; i < NUM_DISCONNECT_PACKETS; i += 1 {
packet := &DisconnectPacket{}
c.sendPacket(packet)
}
}
c.resetConnectionData(reason)
return nil
}
func (c *Client) SendData(payloadData []byte) error {
if c.GetState() != StateConnected {
return ErrClientNotConnected
}
p := NewPayloadPacket(payloadData)
return c.sendPacket(p)
}
func (c *Client) send() error {
// check our send rate prior to bother sending
if c.lastPacketSendTime+float64(1.0/PACKET_SEND_RATE) >= c.time {
return nil
}
switch c.GetState() {
case StateSendingConnectionRequest:
p := &RequestPacket{}
p.VersionInfo = c.connectToken.VersionInfo
p.ProtocolId = c.connectToken.ProtocolId
p.ConnectTokenExpireTimestamp = c.connectToken.ExpireTimestamp
p.ConnectTokenSequence = c.connectToken.Sequence
p.ConnectTokenData = c.connectToken.PrivateData.Buffer()
log.Printf("client[%d] sent connection request packet to server\n", c.id)
return c.sendPacket(p)
case StateSendingConnectionResponse:
p := &ResponsePacket{}
p.ChallengeTokenSequence = c.challengeSequence
p.ChallengeTokenData = c.challengeData
log.Printf("client[%d] sent connection response packet to server\n", c.id)
return c.sendPacket(p)
case StateConnected:
p := &KeepAlivePacket{}
p.ClientIndex = 0
p.MaxClients = 0
log.Printf("client[%d] sent connection keep-alive packet to server\n", c.id)
return c.sendPacket(p)
}
return nil
}
func (c *Client) sendPacket(packet Packet) error {
buffer := make([]byte, MAX_PACKET_BYTES)
packet_bytes, err := packet.Write(buffer, c.connectToken.ProtocolId, c.sequence, c.context.WritePacketKey)
if err != nil {
return err
}
_, err = c.conn.Write(buffer[:packet_bytes])
if err != nil {
log.Printf("error writing packet %s to server: %s\n", packetTypeMap[packet.GetType()], err)
}
c.lastPacketSendTime = c.time
c.sequence++
return err
}
func (c *Client) RecvData() ([]byte, uint64) {
packet := c.packetQueue.Pop()
p, ok := packet.(*PayloadPacket)
if !ok {
return nil, 0
}
return p.PayloadData, p.sequence
}
// write the netcodeData to our unbuffered packet channel. The NetcodeConn verifies
// that the recv'd data is > 0 < maxBytes and is of a valid packet type before
// this is even called.
func (c *Client) handleNetcodeData(packetData *NetcodeData) {
c.packetCh <- packetData
}
func (c *Client) OnPacketData(packetData []byte, from *net.UDPAddr) {
var err error
var size int
var sequence uint64
if !addressEqual(c.serverAddress, from) {
log.Printf("client[%d] unknown/old server address sent us data %s != %s\n", c.id, c.serverAddress.String(), from.String())
return
}
size = len(packetData)
timestamp := uint64(time.Now().Unix())
packet := NewPacket(packetData)
if err = packet.Read(packetData, size, c.connectToken.ProtocolId, timestamp, c.context.ReadPacketKey, nil, c.allowedPackets, c.replayProtection); err != nil {
log.Printf("error reading packet: %s\n", err)
}
c.processPacket(packet, sequence)
}
func (c *Client) processPacket(packet Packet, sequence uint64) {
state := c.GetState()
switch packet.GetType() {
case ConnectionDenied:
if state == StateSendingConnectionRequest || state == StateSendingConnectionResponse {
c.shouldDisconnect = true
c.shouldDisconnectState = StateConnectionDenied
}
case ConnectionChallenge:
if state != StateSendingConnectionRequest {
return
}
p, ok := packet.(*ChallengePacket)
if !ok {
return
}
c.challengeData = p.ChallengeTokenData
c.challengeSequence = p.ChallengeTokenSequence
c.setState(StateSendingConnectionResponse)
case ConnectionKeepAlive:
p, ok := packet.(*KeepAlivePacket)
if !ok {
return
}
if state == StateSendingConnectionResponse {
c.clientIndex = p.ClientIndex
c.maxClients = p.MaxClients
c.setState(StateConnected)
}
case ConnectionPayload:
if state != StateConnected {
return
}
c.packetQueue.Push(packet)
case ConnectionDisconnect:
if state != StateConnected {
return
}
c.shouldDisconnect = true
c.shouldDisconnectState = StateDisconnected
default:
return
}
// always update last packet recv time for valid packets.
c.lastPacketRecvTime = c.time
}