2020-06-12 03:33:56 +00:00
|
|
|
// Copyright 2020 The gVisor Authors.
|
|
|
|
//
|
|
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
|
|
// you may not use this file except in compliance with the License.
|
|
|
|
// You may obtain a copy of the License at
|
|
|
|
//
|
|
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
|
|
//
|
|
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
|
|
// See the License for the specific language governing permissions and
|
|
|
|
// limitations under the License.
|
|
|
|
|
|
|
|
package iptables
|
|
|
|
|
|
|
|
import (
|
|
|
|
"fmt"
|
|
|
|
"unsafe"
|
2021-03-06 17:52:23 +00:00
|
|
|
|
|
|
|
"golang.org/x/sys/unix"
|
2020-06-12 03:33:56 +00:00
|
|
|
)
|
|
|
|
|
|
|
|
type originalDstError struct {
|
2021-03-06 17:52:23 +00:00
|
|
|
errno unix.Errno
|
2020-06-12 03:33:56 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
func (e originalDstError) Error() string {
|
|
|
|
return fmt.Sprintf("errno (%d) when calling getsockopt(SO_ORIGINAL_DST): %v", int(e.errno), e.errno.Error())
|
|
|
|
}
|
|
|
|
|
|
|
|
// SO_ORIGINAL_DST gets the original destination of a redirected packet via
|
|
|
|
// getsockopt.
|
|
|
|
const SO_ORIGINAL_DST = 80
|
|
|
|
|
2021-03-06 17:52:23 +00:00
|
|
|
func originalDestination4(connfd int) (unix.RawSockaddrInet4, error) {
|
|
|
|
var addr unix.RawSockaddrInet4
|
|
|
|
var addrLen uint32 = unix.SizeofSockaddrInet4
|
|
|
|
if errno := originalDestination(connfd, unix.SOL_IP, unsafe.Pointer(&addr), &addrLen); errno != 0 {
|
|
|
|
return unix.RawSockaddrInet4{}, originalDstError{errno}
|
2020-06-12 03:33:56 +00:00
|
|
|
}
|
|
|
|
return addr, nil
|
|
|
|
}
|
|
|
|
|
2021-03-06 17:52:23 +00:00
|
|
|
func originalDestination6(connfd int) (unix.RawSockaddrInet6, error) {
|
|
|
|
var addr unix.RawSockaddrInet6
|
|
|
|
var addrLen uint32 = unix.SizeofSockaddrInet6
|
|
|
|
if errno := originalDestination(connfd, unix.SOL_IPV6, unsafe.Pointer(&addr), &addrLen); errno != 0 {
|
|
|
|
return unix.RawSockaddrInet6{}, originalDstError{errno}
|
2020-06-12 03:33:56 +00:00
|
|
|
}
|
|
|
|
return addr, nil
|
|
|
|
}
|
|
|
|
|
2021-03-06 17:52:23 +00:00
|
|
|
func originalDestination(connfd int, level uintptr, optval unsafe.Pointer, optlen *uint32) unix.Errno {
|
|
|
|
_, _, errno := unix.Syscall6(
|
|
|
|
unix.SYS_GETSOCKOPT,
|
2020-06-12 03:33:56 +00:00
|
|
|
uintptr(connfd),
|
|
|
|
level,
|
|
|
|
SO_ORIGINAL_DST,
|
|
|
|
uintptr(optval),
|
|
|
|
uintptr(unsafe.Pointer(optlen)),
|
|
|
|
0)
|
|
|
|
return errno
|
|
|
|
}
|