53 lines
1.3 KiB
Go
53 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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// +build darwin,!redo
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package netns
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import (
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"fmt"
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"log"
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"strings"
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"syscall"
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"golang.org/x/sys/unix"
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"tailscale.com/net/interfaces"
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)
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// control marks c as necessary to dial in a separate network namespace.
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//
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// It's intentionally the same signature as net.Dialer.Control
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// and net.ListenConfig.Control.
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func control(network, address string, c syscall.RawConn) error {
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if strings.HasPrefix(address, "127.") || address == "::1" {
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// Don't bind to an interface for localhost connections.
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return nil
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}
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idx, err := interfaces.DefaultRouteInterfaceIndex()
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if err != nil {
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log.Printf("netns: DefaultRouteInterfaceIndex: %v", err)
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return nil
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}
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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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var sockErr error
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err = c.Control(func(fd uintptr) {
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sockErr = unix.SetsockoptInt(int(fd), proto, opt, idx)
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})
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if err != nil {
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return fmt.Errorf("RawConn.Control on %T: %w", c, err)
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}
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if sockErr != nil {
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log.Printf("netns: control(%q, %q), v6=%v, index=%v: %v", network, address, v6, idx, sockErr)
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}
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return sockErr
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}
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