mirror of
https://github.com/net-byte/vtun
synced 2024-03-14 10:50:03 +08:00
101 lines
2.1 KiB
Go
101 lines
2.1 KiB
Go
package cmd
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import (
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"fmt"
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"log"
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"net"
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"os"
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"os/exec"
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"runtime"
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"github.com/net-byte/vtun/util"
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"github.com/songgao/water"
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)
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const (
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BufferSize = 1500
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MTU = "1300"
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)
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// New vtun
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func New(local *string, remote *string, port *int, key *string) {
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os := runtime.GOOS
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if "linux" != os {
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log.Fatal("Only support linux!")
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return
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}
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hashKey := util.CreateHash(*key)
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// create tun
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config := water.Config{
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DeviceType: water.TAP,
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}
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config.Name = "vtun"
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iface, err := water.New(config)
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if err != nil {
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log.Fatal(err)
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}
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if nil != err {
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log.Fatalln("Unable to allocate TUN interface:", err)
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}
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log.Println("Interface allocated:", iface.Name())
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// config tun
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configTun(local, iface)
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// start udp listener
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remoteAddr, err := net.ResolveUDPAddr("udp", fmt.Sprintf("%s:%v", *remote, *port))
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if nil != err {
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log.Fatalln("Unable to resolve remote addr:", err)
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}
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localAddr, err := net.ResolveUDPAddr("udp", fmt.Sprintf(":%v", *port))
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if nil != err {
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log.Fatalln("Unable to get UDP socket:", err)
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}
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conn, err := net.ListenUDP("udp", localAddr)
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if nil != err {
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log.Fatalln("Unable to listen on UDP socket:", err)
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}
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defer conn.Close()
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// read data from remote and write data to tun
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go func() {
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buf := make([]byte, BufferSize)
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for {
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n, _, err := conn.ReadFromUDP(buf)
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if err != nil || n == 0 {
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break
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}
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b := buf[:n]
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// decrypt data
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util.Decrypt(&b, hashKey)
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iface.Write(b)
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}
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}()
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// read data from tun and write to remote
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packet := make([]byte, BufferSize)
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for {
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n, err := iface.Read(packet)
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if err != nil || n == 0 {
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break
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}
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b := packet[:n]
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// encrypt data
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util.Encrypt(&b, hashKey)
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conn.WriteToUDP(b, remoteAddr)
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}
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}
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func configTun(local *string, iface *water.Interface) {
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execCmd("/sbin/ip", "link", "set", "dev", iface.Name(), "mtu", MTU)
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execCmd("/sbin/ip", "addr", "add", *local, "dev", iface.Name())
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execCmd("/sbin/ip", "link", "set", "dev", iface.Name(), "up")
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}
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func execCmd(c string, args ...string) {
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cmd := exec.Command(c, args...)
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cmd.Stderr = os.Stderr
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cmd.Stdout = os.Stdout
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cmd.Stdin = os.Stdin
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err := cmd.Run()
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if nil != err {
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log.Fatalln("Error running /sbin/ip:", err)
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}
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}
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