tailscale/net/netns/netns_darwin_tailscaled.go

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