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Copy pathserver.go
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525 lines (433 loc) · 14.4 KB
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package netcode
import (
"fmt"
"log"
"net"
"sync/atomic"
"time"
)
const TIMEOUT_SECONDS = 5 // default timeout for clients
const MAX_SERVER_PACKETS = 64
type Server struct {
serverConn *NetcodeConn
serverAddr *net.UDPAddr
shutdownCh chan struct{}
serverTime float64
running bool
maxClients int
connectedClients int
timeout float64
clientManager *ClientManager
globalSequence uint64
ignoreRequests bool
ignoreResponses bool
allowedPackets []byte
protocolId uint64
privateKey []byte
challengeKey []byte
challengeSequence uint64
recvBytes int
packetCh chan *NetcodeData
}
func NewServer(serverAddress *net.UDPAddr, privateKey []byte, protocolId uint64, maxClients int) *Server {
s := &Server{}
s.serverAddr = serverAddress
s.protocolId = protocolId
s.privateKey = privateKey
s.maxClients = maxClients
s.globalSequence = uint64(1) << 63
s.timeout = float64(TIMEOUT_SECONDS)
s.clientManager = NewClientManager(s.timeout, maxClients)
s.packetCh = make(chan *NetcodeData, s.maxClients*MAX_SERVER_PACKETS*2)
s.shutdownCh = make(chan struct{})
// set allowed packets for this server
s.allowedPackets = make([]byte, ConnectionNumPackets)
s.allowedPackets[ConnectionRequest] = 1
s.allowedPackets[ConnectionResponse] = 1
s.allowedPackets[ConnectionKeepAlive] = 1
s.allowedPackets[ConnectionPayload] = 1
s.allowedPackets[ConnectionDisconnect] = 1
return s
}
func (s *Server) SetAllowedPackets(allowedPackets []byte) {
s.allowedPackets = allowedPackets
}
func (s *Server) SetTimeout(duration time.Duration) {
s.timeout = duration.Seconds()
s.clientManager.setTimeout(s.timeout)
}
func (s *Server) SetIgnoreRequests(val bool) {
s.ignoreRequests = val
}
func (s *Server) SetIgnoreResponses(val bool) {
s.ignoreResponses = val
}
// increments the challenge sequence and returns the un-incremented value
func (s *Server) incChallengeSequence() uint64 {
val := atomic.AddUint64(&s.challengeSequence, 1)
return val - 1
}
func (s *Server) incGlobalSequence() uint64 {
val := atomic.AddUint64(&s.globalSequence, 1)
return val - 1
}
func (s *Server) Init() error {
var err error
s.challengeKey, err = GenerateKey()
if err != nil {
return err
}
s.serverConn = NewNetcodeConn()
s.serverConn.SetReadBuffer(SOCKET_RCVBUF_SIZE * s.maxClients)
s.serverConn.SetWriteBuffer(SOCKET_SNDBUF_SIZE * s.maxClients)
s.serverConn.SetRecvHandler(s.handleNetcodeData)
return nil
}
func (s *Server) Listen() error {
s.running = true
addr := &net.UDPAddr{
Port: s.serverAddr.Port,
IP: net.ParseIP("0.0.0.0"),
}
if err := s.serverConn.Listen(addr); err != nil {
return err
}
return nil
}
func (s *Server) SendPayloads(payloadData []byte) {
if !s.running {
return
}
s.clientManager.sendPayloads(payloadData, s.serverTime)
}
// Sends the payload to the client specified by their clientId.
func (s *Server) SendPayloadToClient(clientId uint64, payloadData []byte) error {
clientIndex, err := s.GetClientIndexByClientId(clientId)
if err != nil {
return err
}
s.clientManager.sendPayloadToInstance(clientIndex, payloadData, s.serverTime)
return nil
}
func (s *Server) Update(time float64) error {
if !s.running {
return ErrServerShutdown
}
s.serverTime = time
// empty recv'd data from channel so we can have safe access to client manager data structures
for {
select {
case recv := <-s.packetCh:
s.OnPacketData(recv.data, recv.from)
default:
goto DONE
}
}
DONE:
s.clientManager.SendKeepAlives(s.serverTime)
s.clientManager.CheckTimeouts(s.serverTime)
return nil
}
// Disconnects a single client via the specified clientId
func (s *Server) DisconnectClient(clientId uint64, sendDisconnect bool) error {
clientIndex, err := s.GetClientIndexByClientId(clientId)
if err != nil {
return err
}
s.clientManager.DisconnectClient(clientIndex, sendDisconnect, s.serverTime)
return nil
}
func (s *Server) GetClientIndexByClientId(clientId uint64) (int, error) {
if !s.running {
return -1, ErrServerNotRunning
}
clientIndex := s.clientManager.FindClientIndexById(clientId)
if clientIndex == -1 {
return -1, fmt.Errorf("unknown client id %d", clientId)
}
return clientIndex, nil
}
// write the netcodeData to our buffered 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.
// NOTE: we will block the netcodeConn from processing which is what we want since
// we want to synchronize access from the Update call.
func (s *Server) handleNetcodeData(packetData *NetcodeData) {
s.packetCh <- packetData
}
func (s *Server) OnPacketData(packetData []byte, addr *net.UDPAddr) {
var readPacketKey []byte
var replayProtection *ReplayProtection
if !s.running {
return
}
size := len(packetData)
encryptionIndex := -1
clientIndex := s.clientManager.FindClientIndexByAddress(addr)
if clientIndex != -1 {
encryptionIndex = s.clientManager.FindEncryptionIndexByClientIndex(clientIndex)
} else {
encryptionIndex = s.clientManager.FindEncryptionEntryIndex(addr, s.serverTime)
}
readPacketKey = s.clientManager.GetEncryptionEntryRecvKey(encryptionIndex)
timestamp := uint64(time.Now().Unix())
packet := NewPacket(packetData)
if clientIndex != -1 {
client := s.clientManager.instances[clientIndex]
replayProtection = client.replayProtection
}
if err := packet.Read(packetData, size, s.protocolId, timestamp, readPacketKey, s.privateKey, s.allowedPackets, replayProtection); err != nil {
log.Printf("error reading packet: %s from %s\n", err, addr)
return
}
s.processPacket(clientIndex, encryptionIndex, packet, addr)
}
func (s *Server) processPacket(clientIndex, encryptionIndex int, packet Packet, addr *net.UDPAddr) {
switch packet.GetType() {
case ConnectionRequest:
if s.ignoreRequests {
return
}
log.Printf("server received connection request from %s\n", addr.String())
s.processConnectionRequest(packet, addr)
case ConnectionResponse:
if s.ignoreResponses {
return
}
log.Printf("server received connection response from %s\n", addr.String())
s.processConnectionResponse(clientIndex, encryptionIndex, packet, addr)
case ConnectionKeepAlive:
if clientIndex == -1 {
return
}
client := s.clientManager.instances[clientIndex]
client.lastRecvTime = s.serverTime
if !client.confirmed {
client.confirmed = true
log.Printf("server confirmed connection to client %d:%s\n", client.clientId, client.address.String())
}
case ConnectionPayload:
if clientIndex == -1 {
return
}
client := s.clientManager.instances[clientIndex]
client.lastRecvTime = s.serverTime
if !client.confirmed {
client.confirmed = true
log.Printf("server confirmed connection to client %d:%s\n", client.clientId, client.address.String())
}
client.packetQueue.Push(packet)
case ConnectionDisconnect:
if clientIndex == -1 {
return
}
client := s.clientManager.instances[clientIndex]
log.Printf("server received disconnect packet from client %d:%s\n", client.clientId, client.address.String())
s.clientManager.disconnectClient(client, false, s.serverTime)
}
}
func (s *Server) processConnectionRequest(packet Packet, addr *net.UDPAddr) {
requestPacket, ok := packet.(*RequestPacket)
if !ok {
return
}
if len(requestPacket.Token.ServerAddrs) == 0 {
log.Printf("server ignored connection request. server address not in connect token whitelist\n")
return
}
addrFound := false
for _, tokenAddr := range requestPacket.Token.ServerAddrs {
if addressEqual(s.serverAddr, &tokenAddr) {
addrFound = true
break
}
}
if !addrFound {
log.Printf("server ignored connection request. server address not in connect token whitelist\n")
return
}
clientIndex := s.clientManager.FindClientIndexByAddress(addr)
if clientIndex != -1 {
log.Printf("server ignored connection request. a client with this address is already connected\n")
return
}
clientIndex = s.clientManager.FindClientIndexById(requestPacket.Token.ClientId)
if clientIndex != -1 {
log.Printf("server ignored connection request. a client with this id has already been used\n")
return
}
if !s.clientManager.FindOrAddTokenEntry(requestPacket.Token.Mac(), addr, s.serverTime) {
log.Printf("server ignored connection request. connect token has already been used\n")
return
}
if s.clientManager.ConnectedClientCount() == s.maxClients {
log.Printf("server denied connection request. server is full\n")
s.sendDeniedPacket(requestPacket.Token.ServerKey, addr)
return
}
if !s.clientManager.AddEncryptionMapping(requestPacket.Token, addr, s.serverTime, s.serverTime+s.timeout) {
log.Printf("server ignored connection request. failed to add encryption mapping\n")
return
}
s.sendChallengePacket(requestPacket, addr)
}
func (s *Server) sendChallengePacket(requestPacket *RequestPacket, addr *net.UDPAddr) {
var bytesWritten int
var err error
challenge := NewChallengeToken(requestPacket.Token.ClientId)
challengeBuf := challenge.Write(requestPacket.Token.UserData)
challengeSequence := s.incChallengeSequence()
if err := EncryptChallengeToken(challengeBuf, challengeSequence, s.challengeKey); err != nil {
log.Printf("server ignored connection request. failed to encrypt challenge token\n")
return
}
challengePacket := &ChallengePacket{}
challengePacket.ChallengeTokenData = challengeBuf
challengePacket.ChallengeTokenSequence = challengeSequence
buffer := make([]byte, MAX_PACKET_BYTES)
if bytesWritten, err = challengePacket.Write(buffer, s.protocolId, s.incGlobalSequence(), requestPacket.Token.ServerKey); err != nil {
log.Printf("server error while writing challenge packet\n")
return
}
s.sendGlobalPacket(buffer[:bytesWritten], addr)
}
func (s *Server) sendGlobalPacket(packetBuffer []byte, addr *net.UDPAddr) {
if _, err := s.serverConn.WriteTo(packetBuffer, addr); err != nil {
log.Printf("error sending packet to %s\n", addr.String())
}
}
func (s *Server) processConnectionResponse(clientIndex, encryptionIndex int, packet Packet, addr *net.UDPAddr) {
var err error
var tokenBuffer []byte
var challengeToken *ChallengeToken
responsePacket, ok := packet.(*ResponsePacket)
if !ok {
return
}
if tokenBuffer, err = DecryptChallengeToken(responsePacket.ChallengeTokenData, responsePacket.ChallengeTokenSequence, s.challengeKey); err != nil {
log.Printf("failed to decrypt challenge token: %s\n", err)
return
}
if challengeToken, err = ReadChallengeToken(tokenBuffer); err != nil {
log.Printf("failed to read challenge token: %s\n", err)
return
}
sendKey := s.clientManager.GetEncryptionEntrySendKey(encryptionIndex)
if sendKey == nil {
log.Printf("server ignored connection response. no packet send key\n")
return
}
if s.clientManager.FindClientIndexByAddress(addr) != -1 {
log.Printf("server ignored connection response. a client with this address is already connected")
return
}
if s.clientManager.FindClientIndexById(challengeToken.ClientId) != -1 {
log.Printf("server ignored connection response. a client with this id is already connected")
return
}
if s.clientManager.ConnectedClientCount() == s.maxClients {
log.Printf("server denied connection response. server is full\n")
s.sendDeniedPacket(sendKey, addr)
return
}
s.connectClient(encryptionIndex, challengeToken, addr)
return
}
func (s *Server) sendDeniedPacket(sendKey []byte, addr *net.UDPAddr) {
var bytesWritten int
var err error
deniedPacket := &DeniedPacket{}
packetBuffer := make([]byte, MAX_PACKET_BYTES)
if bytesWritten, err = deniedPacket.Write(packetBuffer, s.protocolId, s.incGlobalSequence(), sendKey); err != nil {
log.Printf("error creating denied packet: %s\n", err)
return
}
s.sendGlobalPacket(packetBuffer[:bytesWritten], addr)
}
func (s *Server) connectClient(encryptionIndex int, challengeToken *ChallengeToken, addr *net.UDPAddr) {
if s.clientManager.ConnectedClientCount() > s.maxClients {
log.Printf("maxium number of clients reached")
return
}
s.clientManager.SetEncryptionEntryExpiration(encryptionIndex, -1)
client := s.clientManager.ConnectClient(addr, challengeToken)
if client == nil {
return
}
client.serverConn = s.serverConn
client.encryptionIndex = encryptionIndex
client.protocolId = s.protocolId
client.lastSendTime = s.serverTime
client.lastRecvTime = s.serverTime
log.Printf("server accepted client %d from %s in slot: %d\n", client.clientId, addr.String(), client.clientIndex)
s.sendKeepAlive(client)
}
func (s *Server) sendKeepAlive(client *ClientInstance) {
clientIndex := client.clientIndex
packet := &KeepAlivePacket{}
packet.ClientIndex = uint32(clientIndex)
packet.MaxClients = uint32(s.maxClients)
if !s.clientManager.TouchEncryptionEntry(client.encryptionIndex, client.address, s.serverTime) {
log.Printf("error: encryption mapping is out of date for client %d encIndex: %d addr: %s\n", clientIndex, client.encryptionIndex, client.address.String())
return
}
writePacketKey := s.clientManager.GetEncryptionEntrySendKey(client.encryptionIndex)
if writePacketKey == nil {
log.Printf("error: unable to retrieve encryption key for client: %d\n", clientIndex)
return
}
if err := client.SendPacket(packet, writePacketKey, s.serverTime); err != nil {
log.Printf("%s\n", err)
}
}
func (s *Server) GetConnectedClientIds() []uint64 {
return s.clientManager.ConnectedClients()
}
func (s *Server) MaxClients() int {
return s.maxClients
}
func (s *Server) HasClients() int {
return s.clientManager.ConnectedClientCount()
}
func (s *Server) GetClientUserData(clientId uint64) ([]byte, error) {
i, err := s.GetClientIndexByClientId(clientId)
if err != nil {
return nil, err
}
return s.clientManager.instances[i].userData, nil
}
func (s *Server) Stop() error {
if !s.running {
return nil
}
s.clientManager.disconnectClients(s.serverTime)
s.running = false
s.maxClients = 0
s.globalSequence = 0
s.challengeSequence = 0
s.challengeKey = make([]byte, KEY_BYTES)
s.clientManager.resetCryptoEntries()
s.clientManager.resetTokenEntries()
close(s.shutdownCh)
s.running = false
s.serverConn.Close()
return nil
}
func (s *Server) RecvPayload(clientIndex int) ([]byte, uint64) {
packet := s.clientManager.instances[clientIndex].packetQueue.Pop()
if packet == nil {
return []byte{}, 0
}
p, ok := packet.(*PayloadPacket)
if !ok {
log.Printf("not a payload packet")
return []byte{}, 0
}
return p.PayloadData, p.sequence
}
func addressEqual(addr1, addr2 *net.UDPAddr) bool {
if addr1 == nil || addr2 == nil {
return false
}
return addr1.IP.Equal(addr2.IP) && addr1.Port == addr2.Port
}