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tailscale/ipn/ipnlocal/peerapi_macios_ext.go

85 lines
2.2 KiB
Go

// 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.
// +build darwin,redo ios,redo
package ipnlocal
import (
"errors"
"fmt"
"log"
"net"
"strings"
"syscall"
"golang.org/x/sys/unix"
"inet.af/netaddr"
"tailscale.com/net/interfaces"
)
func init() {
initListenConfig = initListenConfigNetworkExtension
peerDialControlFunc = peerDialControlFuncNetworkExtension
}
// initListenConfigNetworkExtension configures nc for listening on IP
// through the iOS/macOS Network/System Extension (Packet Tunnel
// Provider) sandbox.
func initListenConfigNetworkExtension(nc *net.ListenConfig, ip netaddr.IP, st *interfaces.State, tunIfName string) error {
tunIf, ok := st.Interface[tunIfName]
if !ok {
return fmt.Errorf("no interface with name %q", tunIfName)
}
nc.Control = func(network, address string, c syscall.RawConn) error {
var sockErr error
err := c.Control(func(fd uintptr) {
sockErr = bindIf(fd, network, address, tunIf.Index)
log.Printf("peerapi: bind(%q, %q) on index %v = %v", network, address, tunIf.Index, sockErr)
})
if err != nil {
return err
}
return sockErr
}
return nil
}
func bindIf(fd uintptr, network, address string, ifIndex int) error {
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
}
return unix.SetsockoptInt(int(fd), proto, opt, ifIndex)
}
func peerDialControlFuncNetworkExtension(b *LocalBackend) func(network, address string, c syscall.RawConn) error {
b.mu.Lock()
defer b.mu.Unlock()
st := b.prevIfState
pas := b.peerAPIServer
index := -1
if st != nil && pas != nil && pas.tunName != "" {
if tunIf, ok := st.Interface[pas.tunName]; ok {
index = tunIf.Index
}
}
return func(network, address string, c syscall.RawConn) error {
if index == -1 {
return errors.New("failed to find TUN interface to bind to")
}
var sockErr error
err := c.Control(func(fd uintptr) {
sockErr = bindIf(fd, network, address, index)
})
if err != nil {
return err
}
return sockErr
}
}