mirror of
https://github.com/KusakabeShi/EtherGuard-VPN.git
synced 2024-11-28 18:23:08 +01:00
83 lines
2.1 KiB
Go
83 lines
2.1 KiB
Go
/* SPDX-License-Identifier: MIT
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*
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* Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
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*/
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package tap
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import (
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"encoding/binary"
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"errors"
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"strconv"
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"strings"
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)
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type Event int
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type MacAddress [6]uint8
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func GetDstMacAddr(packet []byte) (dstMacAddr MacAddress) {
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copy(dstMacAddr[:], packet[0:6])
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return
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}
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func GetSrcMacAddr(packet []byte) (srcMacAddr MacAddress) {
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copy(srcMacAddr[:], packet[6:12])
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return
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}
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func GetMacAddr(prefix string, uid uint32) (mac MacAddress, err error) {
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macprefix, _, err := prefixStr2prefix(prefix)
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if err != nil {
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return
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}
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idbuf := make([]byte, 4)
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binary.BigEndian.PutUint32(idbuf, uid)
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copy(mac[2:], idbuf)
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copy(mac[:], macprefix)
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if IsNotUnicast(mac) {
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err = errors.New("ERROR: MAC address can only set to unicast address")
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return
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}
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return
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}
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func prefixStr2prefix(prefix string) ([]uint8, uint32, error) {
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hexStrs := strings.Split(strings.ToLower(prefix), ":")
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retprefix := make([]uint8, len(hexStrs))
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maxID := uint32(1)<<((6-len(hexStrs))*8) - 1
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if len(hexStrs) < 2 || len(hexStrs) > 6 {
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return []uint8{}, 0, errors.New("Macaddr prefix length must between 2 and 6, " + prefix + " is " + strconv.Itoa(len(hexStrs)))
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}
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for index, hexstr := range hexStrs {
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value, err := strconv.ParseInt(hexstr, 16, 16)
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if err != nil {
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return []uint8{}, 0, err
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}
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retprefix[index] = uint8(value)
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}
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return retprefix, maxID, nil
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}
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func IsNotUnicast(mac_in MacAddress) bool {
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if mac_in[0]&1 == 0 { // Is unicast
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return false
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}
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return true
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}
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const (
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EventUp = 1 << iota
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EventDown
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EventMTUUpdate
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)
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type Device interface {
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Read([]byte, int) (int, error) // read a packet from the device (without any additional headers)
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Write([]byte, int) (int, error) // writes a packet to the device (without any additional headers)
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Flush() error // flush all previous writes to the device
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MTU() (int, error) // returns the MTU of the device
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Name() (string, error) // fetches and returns the current name
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Events() chan Event // returns a constant channel of events related to the device
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Close() error // stops the device and closes the event channel
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}
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