func NewServer(port int, local_ip string, key []byte) (*Server, error) {
ip := net.ParseIP(local_ip)
log.Printf("Creating TUN device")
tun, err := tun.NewTun(DeviceNameServer, local_ip)
if err != nil {
return nil, err
}
addr, err := net.ResolveUDPAddr("udp", ":"+strconv.Itoa(port))
if err != nil {
tun.Close()
return nil, err
}
log.Printf("Listening UDP connections on %s.", addr.String())
conn, err := net.ListenUDP("udp", addr)
if err != nil {
tun.Close()
return nil, err
}
return &Server{
tun,
conn,
NewSessionTable(ip),
key,
}, nil
}
func (c *Client) init() error {
msg := &message.Message{
Kind: message.Message_REQUEST.Enum(),
}
log.Printf("Sending request to %s.", c.serverConnection.RemoteAddr().String())
data, err := proto.Marshal(msg)
if err != nil {
return err
}
data, err = crypto.Encrypt(c.secretKey, data)
if err != nil {
return err
}
success := false
buf := make([]byte, 1600)
for !success {
_, err = c.serverConnection.Write(data)
if err != nil {
return err
}
c.serverConnection.SetReadDeadline(time.Now().Add(5 * time.Second))
n, err := c.serverConnection.Read(buf)
c.serverConnection.SetReadDeadline(time.Time{})
if err != nil {
log.Printf("Read error: %v. Reconnecting...", err)
continue
}
buf = buf[:n]
success = true
}
buf, err = crypto.Decrypt(c.secretKey, buf)
if err != nil {
return err
}
msg = &message.Message{}
err = proto.Unmarshal(buf, msg)
if *msg.Kind != message.Message_ACCEPT {
return errors.New("Unexpected message type.")
}
var local_ip net.IP
local_ip = msg.Data
log.Printf("Client IP %s assigned.", local_ip.String())
c.device, err = tun.NewTun(DeviceNameClient, local_ip.String())
if err != nil {
return err
}
local_ip[3] = 0x1
c.gatewayAddress, err = util.DefaultGateway()
if err != nil {
return err
}
err = util.SetGatewayForHost(c.gatewayAddress, c.serverAddress)
if err != nil {
return err
}
err = util.ClearGateway()
if err != nil {
return err
}
err = util.SetDefaultGateway(local_ip.String())
if err != nil {
return err
}
return nil
}