mirror of
https://github.com/net-byte/vtun
synced 2024-03-14 10:50:03 +08:00
103 lines
2.3 KiB
Go
103 lines
2.3 KiB
Go
package udp
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import (
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"log"
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"net"
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"time"
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"github.com/golang/snappy"
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"github.com/net-byte/vtun/common/cipher"
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"github.com/net-byte/vtun/common/config"
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"github.com/net-byte/vtun/common/netutil"
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"github.com/net-byte/vtun/tun"
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"github.com/patrickmn/go-cache"
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"github.com/songgao/water"
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"golang.org/x/net/ipv4"
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"golang.org/x/net/ipv6"
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)
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// StartServer starts the udp server
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func StartServer(config config.Config) {
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log.Printf("vtun udp server started on %v", config.LocalAddr)
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iface := tun.CreateTun(config)
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localAddr, err := net.ResolveUDPAddr("udp", config.LocalAddr)
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if err != nil {
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log.Fatalln("failed to get udp socket:", err)
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}
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conn, err := net.ListenUDP("udp", localAddr)
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if err != nil {
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log.Fatalln("failed to listen on udp socket:", err)
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}
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if localAddr.IP.To4() != nil {
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p := ipv4.NewPacketConn(conn)
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if err := p.SetTOS(0xb8); err != nil { // DSCP EF
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log.Fatalln("failed to set conn tos:", err)
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}
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} else {
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p := ipv6.NewPacketConn(conn)
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if err := p.SetTrafficClass(0xb8); err != nil { // DSCP EF
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log.Fatalln("failed to set conn tos:", err)
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}
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}
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defer conn.Close()
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s := &Server{config: config, iface: iface, localConn: conn, connCache: cache.New(30*time.Minute, 10*time.Minute)}
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go s.tunToUdp()
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s.udpToTun()
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}
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// the server struct
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type Server struct {
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config config.Config
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iface *water.Interface
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localConn *net.UDPConn
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connCache *cache.Cache
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}
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// tunToUdp sends packets from tun to udp
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func (s *Server) tunToUdp() {
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packet := make([]byte, s.config.MTU)
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for {
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n, err := s.iface.Read(packet)
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if err != nil || n == 0 {
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continue
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}
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b := packet[:n]
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if key := netutil.GetDstKey(b); key != "" {
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if v, ok := s.connCache.Get(key); ok {
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if s.config.Obfs {
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b = cipher.XOR(b)
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}
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if s.config.Compress {
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b = snappy.Encode(nil, b)
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}
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s.localConn.WriteToUDP(b, v.(*net.UDPAddr))
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}
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}
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}
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}
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// udpToTun sends packets from udp to tun
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func (s *Server) udpToTun() {
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packet := make([]byte, s.config.MTU)
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for {
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n, cliAddr, err := s.localConn.ReadFromUDP(packet)
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if err != nil || n == 0 {
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continue
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}
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b := packet[:n]
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if s.config.Compress {
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b, err = snappy.Decode(nil, b)
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if err != nil {
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continue
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}
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}
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if s.config.Obfs {
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b = cipher.XOR(b)
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}
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if key := netutil.GetSrcKey(b); key != "" {
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s.iface.Write(b)
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s.connCache.Set(key, cliAddr, cache.DefaultExpiration)
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}
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}
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}
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