mirror of
https://github.com/cwinfo/yggdrasil-go.git
synced 2024-11-13 02:50:28 +00:00
100 lines
2.0 KiB
Go
100 lines
2.0 KiB
Go
package yggdrasil
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// This manages the tun driver to send/recv packets to/from applications
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import ethernet "github.com/songgao/packets/ethernet"
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const IPv6_HEADER_LENGTH = 40
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const ETHER_HEADER_LENGTH = 14
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type tunInterface interface {
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IsTUN() bool
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IsTAP() bool
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Name() string
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Read(to []byte) (int, error)
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Write(from []byte) (int, error)
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Close() error
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}
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type tunDevice struct {
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core *Core
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icmpv6 icmpv6
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send chan<- []byte
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recv <-chan []byte
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mtu int
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iface tunInterface
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}
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func (tun *tunDevice) init(core *Core) {
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tun.core = core
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tun.icmpv6.init(tun)
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}
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func (tun *tunDevice) write() error {
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for {
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data := <-tun.recv
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if tun.iface == nil {
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continue
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}
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if tun.iface.IsTAP() {
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var frame ethernet.Frame
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frame.Prepare(
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tun.icmpv6.peermac[:6], // Destination MAC address
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tun.icmpv6.mymac[:6], // Source MAC address
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ethernet.NotTagged, // VLAN tagging
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ethernet.IPv6, // Ethertype
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len(data)) // Payload length
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copy(frame[ETHER_HEADER_LENGTH:], data[:])
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if _, err := tun.iface.Write(frame); err != nil {
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panic(err)
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}
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} else {
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if _, err := tun.iface.Write(data); err != nil {
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panic(err)
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}
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}
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util_putBytes(data)
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}
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}
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func (tun *tunDevice) read() error {
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mtu := tun.mtu
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if tun.iface.IsTAP() {
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mtu += ETHER_HEADER_LENGTH
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}
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buf := make([]byte, mtu)
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for {
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n, err := tun.iface.Read(buf)
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if err != nil {
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// panic(err)
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return err
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}
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o := 0
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if tun.iface.IsTAP() {
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o = ETHER_HEADER_LENGTH
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}
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if buf[o]&0xf0 != 0x60 ||
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n != 256*int(buf[o+4])+int(buf[o+5])+IPv6_HEADER_LENGTH+o {
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// Either not an IPv6 packet or not the complete packet for some reason
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//panic("Should not happen in testing")
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continue
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}
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if buf[o+6] == 58 {
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// Found an ICMPv6 packet
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b := make([]byte, n)
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copy(b, buf)
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// tun.icmpv6.recv <- b
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go tun.icmpv6.parse_packet(b)
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}
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packet := append(util_getBytes(), buf[o:n]...)
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tun.send <- packet
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}
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}
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func (tun *tunDevice) close() error {
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if tun.iface == nil {
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return nil
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}
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return tun.iface.Close()
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}
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