47 lines
1.2 KiB
Go
47 lines
1.2 KiB
Go
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// Copyright (c) 2020 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 linux
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package netns
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import (
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"fmt"
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"syscall"
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"golang.org/x/sys/unix"
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)
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// tailscaleBypassMark is the mark indicating that packets originating
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// from a socket should bypass Tailscale-managed routes during routing
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// table lookups.
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//
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// Keep this in sync with tailscaleBypassMark in
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// wgengine/router/router_linux.go.
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const tailscaleBypassMark = 0x20000
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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 skipPrivileged.Get() {
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// We can't set socket marks without CAP_NET_ADMIN on linux,
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// skip as requested.
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return nil
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}
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var controlErr error
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err := c.Control(func(fd uintptr) {
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controlErr = unix.SetsockoptInt(int(fd), unix.SOL_SOCKET, unix.SO_MARK, tailscaleBypassMark)
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})
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if err != nil {
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return fmt.Errorf("setting socket mark: %w", err)
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}
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if controlErr != nil {
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return fmt.Errorf("setting socket mark: %w", controlErr)
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}
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return nil
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}
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