tailscale/net/netns/netns_macios.go

55 lines
1.3 KiB
Go

// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build darwin || ios
// +build darwin ios
package netns
import (
"errors"
"log"
"net"
"strings"
"syscall"
"golang.org/x/sys/unix"
)
// SetListenConfigInterfaceIndex sets lc.Control such that sockets are bound
// to the provided interface index.
func SetListenConfigInterfaceIndex(lc *net.ListenConfig, ifIndex int) error {
if lc == nil {
return errors.New("nil ListenConfig")
}
if lc.Control != nil {
return errors.New("ListenConfig.Control already set")
}
lc.Control = func(network, address string, c syscall.RawConn) error {
var sockErr error
err := c.Control(func(fd uintptr) {
sockErr = bindInterface(fd, network, address, ifIndex)
if sockErr != nil {
log.Printf("netns: bind(%q, %q) on index %v: %v", network, address, ifIndex, sockErr)
}
})
if err != nil {
return err
}
return sockErr
}
return nil
}
func bindInterface(fd uintptr, network, address string, ifIndex int) error {
v6 := strings.Contains(address, "]:") || strings.HasSuffix(network, "6") // hacky test for v6
proto := unix.IPPROTO_IP
opt := unix.IP_BOUND_IF
if v6 {
proto = unix.IPPROTO_IPV6
opt = unix.IPV6_BOUND_IF
}
return unix.SetsockoptInt(int(fd), proto, opt, ifIndex)
}