From fa37039c3bbadf902cef87ae92c9c624f0991942 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Dominik=20S=C3=BC=C3=9F?= <dominik.suess@outlook.at>
Date: Tue, 13 Feb 2018 16:43:07 +0100
Subject: [PATCH] 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>
---
tun_linux.go | 70 ++++++++++++++++++++++------------------------------
1 file changed, 30 insertions(+), 40 deletions(-)
diff --git a/tun_linux.go b/tun_linux.go
index daa2462..b35e08d 100644
--- a/tun_linux.go
+++ b/tun_linux.go
@@ -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")