// 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" "log" "strings" "syscall" "golang.org/x/sys/unix" "tailscale.com/net/interfaces" ) // control 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 control(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 { log.Printf("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 { log.Printf("netns: control(%q, %q), v6=%v, index=%v: %v", network, address, v6, idx, sockErr) } return sockErr }