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