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Reimplemented bind_rtmgrp in pure Go

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Getting rid of the Cgo dependency for listing on netlink.

Ported original patch from "syscall" to "golang.org/x/sys/unix".

Signed-off-by: Dominik Süß <dominik.suess@outlook.at>
Co-Authored-By: Mathias Hall-Andersen <mathias@hall-andersen.dk>
This commit is contained in:
Dominik Süß 2018-02-13 16:43:07 +01:00 committed by Mathias Hall-Andersen
parent ff8f3a412e
commit fa37039c3b
1 changed files with 30 additions and 40 deletions
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70
tun_linux.go
View file

@ -16,38 +16,9 @@ import (
"unsafe"
)
// #include <string.h>
// #include <unistd.h>
// #include <net/if.h>
// #include <netinet/in.h>
// #include <linux/netlink.h>
// #include <linux/rtnetlink.h>
//
// /* Creates a netlink socket
// * listening to the RTMGRP_LINK multicast group
// */
//
// int bind_rtmgrp() {
// int nl_sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
// if (nl_sock < 0)
// return -1;
//
// struct sockaddr_nl addr;
// memset ((void *) &addr, 0, sizeof (addr));
// addr.nl_family = AF_NETLINK;
// addr.nl_pid = getpid ();
// addr.nl_groups = RTMGRP_LINK | RTMGRP_IPV4_IFADDR | RTMGRP_IPV6_IFADDR;
//
// if (bind(nl_sock, (struct sockaddr *) &addr, sizeof (addr)) < 0)
// return -1;
//
// return nl_sock;
// }
import "C"
const (
CloneDevicePath = "/dev/net/tun"
IFReqSize = unix.IFNAMSIZ + 64
cloneDevicePath = "/dev/net/tun"
ifReqSize = unix.IFNAMSIZ + 64
)
type NativeTun struct {
@ -58,6 +29,26 @@ type NativeTun struct {
events chan TUNEvent // device related events
}
func toRTMGRP(sc uint) uint {
return 1 << (sc - 1)
}
func (tun *NativeTun) bindRTMGRP() (int, error) {
groups := toRTMGRP(unix.RTNLGRP_LINK)
groups |= toRTMGRP(unix.RTNLGRP_IPV4_IFADDR)
groups |= toRTMGRP(unix.RTNLGRP_IPV6_IFADDR)
sock, err := unix.Socket(unix.AF_NETLINK, unix.SOCK_RAW, unix.NETLINK_ROUTE)
if err != nil {
return 0, err
}
saddr := &unix.SockaddrNetlink{
Family: unix.AF_NETLINK,
Pid: uint32(os.Getpid()),
Groups: uint32(groups),
}
return sock, unix.Bind(sock, saddr)
}
func (tun *NativeTun) File() *os.File {
return tun.fd
}
@ -81,9 +72,8 @@ func (tun *NativeTun) RoutineHackListener() {
}
func (tun *NativeTun) RoutineNetlinkListener() {
sock := int(C.bind_rtmgrp())
if sock < 0 {
sock, err := tun.bindRTMGRP()
if err != nil {
tun.errors <- errors.New("Failed to create netlink event listener")
return
}
@ -159,7 +149,7 @@ func getIFIndex(name string) (int32, error) {
defer unix.Close(fd)
var ifr [IFReqSize]byte
var ifr [ifReqSize]byte
copy(ifr[:], name)
_, _, errno := unix.Syscall(
unix.SYS_IOCTL,
@ -194,7 +184,7 @@ func (tun *NativeTun) setMTU(n int) error {
// do ioctl call
var ifr [IFReqSize]byte
var ifr [ifReqSize]byte
copy(ifr[:], tun.name)
binary.LittleEndian.PutUint32(ifr[16:20], uint32(n))
_, _, errno := unix.Syscall(
@ -229,7 +219,7 @@ func (tun *NativeTun) MTU() (int, error) {
// do ioctl call
var ifr [IFReqSize]byte
var ifr [ifReqSize]byte
copy(ifr[:], tun.name)
_, _, errno := unix.Syscall(
unix.SYS_IOCTL,
@ -324,15 +314,15 @@ func CreateTUN(name string) (TUNDevice, error) {
// open clone device
fd, err := os.OpenFile(CloneDevicePath, os.O_RDWR, 0)
fd, err := os.OpenFile(cloneDevicePath, os.O_RDWR, 0)
if err != nil {
return nil, err
}
// create new device
var ifr [IFReqSize]byte
var flags uint16 = unix.IFF_TUN // | unix.IFF_NO_PI
var ifr [ifReqSize]byte
var flags uint16 = unix.IFF_TUN // | unix.IFF_NO_PI (disabled for TUN status hack)
nameBytes := []byte(name)
if len(nameBytes) >= unix.IFNAMSIZ {
return nil, errors.New("Interface name too long")