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mirror of https://git.zx2c4.com/wireguard-go synced 2024-11-15 01:05:15 +01:00
wireguard-go/conn/conn_linux.go
David Crawshaw c4a8eab3dd conn: new package that splits out the Bind and Endpoint types
The sticky socket code stays in the device package for now,
as it reaches deeply into the peer list.

This is the first step in an effort to split some code out of
the very busy device package.

Signed-off-by: David Crawshaw <crawshaw@tailscale.com>
2020-03-30 21:05:11 +11:00

572 lines
10 KiB
Go

// +build !android
/* SPDX-License-Identifier: MIT
*
* Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
*/
package conn
import (
"errors"
"net"
"strconv"
"sync"
"syscall"
"unsafe"
"golang.org/x/sys/unix"
)
const (
FD_ERR = -1
)
type IPv4Source struct {
Src [4]byte
Ifindex int32
}
type IPv6Source struct {
src [16]byte
//ifindex belongs in dst.ZoneId
}
type NativeEndpoint struct {
sync.Mutex
dst [unsafe.Sizeof(unix.SockaddrInet6{})]byte
src [unsafe.Sizeof(IPv6Source{})]byte
isV6 bool
}
func (endpoint *NativeEndpoint) Src4() *IPv4Source { return endpoint.src4() }
func (endpoint *NativeEndpoint) Dst4() *unix.SockaddrInet4 { return endpoint.dst4() }
func (endpoint *NativeEndpoint) IsV6() bool { return endpoint.isV6 }
func (endpoint *NativeEndpoint) src4() *IPv4Source {
return (*IPv4Source)(unsafe.Pointer(&endpoint.src[0]))
}
func (endpoint *NativeEndpoint) src6() *IPv6Source {
return (*IPv6Source)(unsafe.Pointer(&endpoint.src[0]))
}
func (endpoint *NativeEndpoint) dst4() *unix.SockaddrInet4 {
return (*unix.SockaddrInet4)(unsafe.Pointer(&endpoint.dst[0]))
}
func (endpoint *NativeEndpoint) dst6() *unix.SockaddrInet6 {
return (*unix.SockaddrInet6)(unsafe.Pointer(&endpoint.dst[0]))
}
type nativeBind struct {
sock4 int
sock6 int
lastMark uint32
}
var _ Endpoint = (*NativeEndpoint)(nil)
var _ Bind = (*nativeBind)(nil)
func CreateEndpoint(s string) (Endpoint, error) {
var end NativeEndpoint
addr, err := parseEndpoint(s)
if err != nil {
return nil, err
}
ipv4 := addr.IP.To4()
if ipv4 != nil {
dst := end.dst4()
end.isV6 = false
dst.Port = addr.Port
copy(dst.Addr[:], ipv4)
end.ClearSrc()
return &end, nil
}
ipv6 := addr.IP.To16()
if ipv6 != nil {
zone, err := zoneToUint32(addr.Zone)
if err != nil {
return nil, err
}
dst := end.dst6()
end.isV6 = true
dst.Port = addr.Port
dst.ZoneId = zone
copy(dst.Addr[:], ipv6[:])
end.ClearSrc()
return &end, nil
}
return nil, errors.New("Invalid IP address")
}
func createBind(port uint16) (Bind, uint16, error) {
var err error
var bind nativeBind
var newPort uint16
// Attempt ipv6 bind, update port if successful.
bind.sock6, newPort, err = create6(port)
if err != nil {
if err != syscall.EAFNOSUPPORT {
return nil, 0, err
}
} else {
port = newPort
}
// Attempt ipv4 bind, update port if successful.
bind.sock4, newPort, err = create4(port)
if err != nil {
if err != syscall.EAFNOSUPPORT {
unix.Close(bind.sock6)
return nil, 0, err
}
} else {
port = newPort
}
if bind.sock4 == FD_ERR && bind.sock6 == FD_ERR {
return nil, 0, errors.New("ipv4 and ipv6 not supported")
}
return &bind, port, nil
}
func (bind *nativeBind) LastMark() uint32 {
return bind.lastMark
}
func (bind *nativeBind) SetMark(value uint32) error {
if bind.sock6 != -1 {
err := unix.SetsockoptInt(
bind.sock6,
unix.SOL_SOCKET,
unix.SO_MARK,
int(value),
)
if err != nil {
return err
}
}
if bind.sock4 != -1 {
err := unix.SetsockoptInt(
bind.sock4,
unix.SOL_SOCKET,
unix.SO_MARK,
int(value),
)
if err != nil {
return err
}
}
bind.lastMark = value
return nil
}
func closeUnblock(fd int) error {
// shutdown to unblock readers and writers
unix.Shutdown(fd, unix.SHUT_RDWR)
return unix.Close(fd)
}
func (bind *nativeBind) Close() error {
var err1, err2 error
if bind.sock6 != -1 {
err1 = closeUnblock(bind.sock6)
}
if bind.sock4 != -1 {
err2 = closeUnblock(bind.sock4)
}
if err1 != nil {
return err1
}
return err2
}
func (bind *nativeBind) ReceiveIPv6(buff []byte) (int, Endpoint, error) {
var end NativeEndpoint
if bind.sock6 == -1 {
return 0, nil, syscall.EAFNOSUPPORT
}
n, err := receive6(
bind.sock6,
buff,
&end,
)
return n, &end, err
}
func (bind *nativeBind) ReceiveIPv4(buff []byte) (int, Endpoint, error) {
var end NativeEndpoint
if bind.sock4 == -1 {
return 0, nil, syscall.EAFNOSUPPORT
}
n, err := receive4(
bind.sock4,
buff,
&end,
)
return n, &end, err
}
func (bind *nativeBind) Send(buff []byte, end Endpoint) error {
nend := end.(*NativeEndpoint)
if !nend.isV6 {
if bind.sock4 == -1 {
return syscall.EAFNOSUPPORT
}
return send4(bind.sock4, nend, buff)
} else {
if bind.sock6 == -1 {
return syscall.EAFNOSUPPORT
}
return send6(bind.sock6, nend, buff)
}
}
func (end *NativeEndpoint) SrcIP() net.IP {
if !end.isV6 {
return net.IPv4(
end.src4().Src[0],
end.src4().Src[1],
end.src4().Src[2],
end.src4().Src[3],
)
} else {
return end.src6().src[:]
}
}
func (end *NativeEndpoint) DstIP() net.IP {
if !end.isV6 {
return net.IPv4(
end.dst4().Addr[0],
end.dst4().Addr[1],
end.dst4().Addr[2],
end.dst4().Addr[3],
)
} else {
return end.dst6().Addr[:]
}
}
func (end *NativeEndpoint) DstToBytes() []byte {
if !end.isV6 {
return (*[unsafe.Offsetof(end.dst4().Addr) + unsafe.Sizeof(end.dst4().Addr)]byte)(unsafe.Pointer(end.dst4()))[:]
} else {
return (*[unsafe.Offsetof(end.dst6().Addr) + unsafe.Sizeof(end.dst6().Addr)]byte)(unsafe.Pointer(end.dst6()))[:]
}
}
func (end *NativeEndpoint) SrcToString() string {
return end.SrcIP().String()
}
func (end *NativeEndpoint) DstToString() string {
var udpAddr net.UDPAddr
udpAddr.IP = end.DstIP()
if !end.isV6 {
udpAddr.Port = end.dst4().Port
} else {
udpAddr.Port = end.dst6().Port
}
return udpAddr.String()
}
func (end *NativeEndpoint) ClearDst() {
for i := range end.dst {
end.dst[i] = 0
}
}
func (end *NativeEndpoint) ClearSrc() {
for i := range end.src {
end.src[i] = 0
}
}
func zoneToUint32(zone string) (uint32, error) {
if zone == "" {
return 0, nil
}
if intr, err := net.InterfaceByName(zone); err == nil {
return uint32(intr.Index), nil
}
n, err := strconv.ParseUint(zone, 10, 32)
return uint32(n), err
}
func create4(port uint16) (int, uint16, error) {
// create socket
fd, err := unix.Socket(
unix.AF_INET,
unix.SOCK_DGRAM,
0,
)
if err != nil {
return FD_ERR, 0, err
}
addr := unix.SockaddrInet4{
Port: int(port),
}
// set sockopts and bind
if err := func() error {
if err := unix.SetsockoptInt(
fd,
unix.SOL_SOCKET,
unix.SO_REUSEADDR,
1,
); err != nil {
return err
}
if err := unix.SetsockoptInt(
fd,
unix.IPPROTO_IP,
unix.IP_PKTINFO,
1,
); err != nil {
return err
}
return unix.Bind(fd, &addr)
}(); err != nil {
unix.Close(fd)
return FD_ERR, 0, err
}
sa, err := unix.Getsockname(fd)
if err == nil {
addr.Port = sa.(*unix.SockaddrInet4).Port
}
return fd, uint16(addr.Port), err
}
func create6(port uint16) (int, uint16, error) {
// create socket
fd, err := unix.Socket(
unix.AF_INET6,
unix.SOCK_DGRAM,
0,
)
if err != nil {
return FD_ERR, 0, err
}
// set sockopts and bind
addr := unix.SockaddrInet6{
Port: int(port),
}
if err := func() error {
if err := unix.SetsockoptInt(
fd,
unix.SOL_SOCKET,
unix.SO_REUSEADDR,
1,
); err != nil {
return err
}
if err := unix.SetsockoptInt(
fd,
unix.IPPROTO_IPV6,
unix.IPV6_RECVPKTINFO,
1,
); err != nil {
return err
}
if err := unix.SetsockoptInt(
fd,
unix.IPPROTO_IPV6,
unix.IPV6_V6ONLY,
1,
); err != nil {
return err
}
return unix.Bind(fd, &addr)
}(); err != nil {
unix.Close(fd)
return FD_ERR, 0, err
}
sa, err := unix.Getsockname(fd)
if err == nil {
addr.Port = sa.(*unix.SockaddrInet6).Port
}
return fd, uint16(addr.Port), err
}
func send4(sock int, end *NativeEndpoint, buff []byte) error {
// construct message header
cmsg := struct {
cmsghdr unix.Cmsghdr
pktinfo unix.Inet4Pktinfo
}{
unix.Cmsghdr{
Level: unix.IPPROTO_IP,
Type: unix.IP_PKTINFO,
Len: unix.SizeofInet4Pktinfo + unix.SizeofCmsghdr,
},
unix.Inet4Pktinfo{
Spec_dst: end.src4().Src,
Ifindex: end.src4().Ifindex,
},
}
end.Lock()
_, err := unix.SendmsgN(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], end.dst4(), 0)
end.Unlock()
if err == nil {
return nil
}
// clear src and retry
if err == unix.EINVAL {
end.ClearSrc()
cmsg.pktinfo = unix.Inet4Pktinfo{}
end.Lock()
_, err = unix.SendmsgN(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], end.dst4(), 0)
end.Unlock()
}
return err
}
func send6(sock int, end *NativeEndpoint, buff []byte) error {
// construct message header
cmsg := struct {
cmsghdr unix.Cmsghdr
pktinfo unix.Inet6Pktinfo
}{
unix.Cmsghdr{
Level: unix.IPPROTO_IPV6,
Type: unix.IPV6_PKTINFO,
Len: unix.SizeofInet6Pktinfo + unix.SizeofCmsghdr,
},
unix.Inet6Pktinfo{
Addr: end.src6().src,
Ifindex: end.dst6().ZoneId,
},
}
if cmsg.pktinfo.Addr == [16]byte{} {
cmsg.pktinfo.Ifindex = 0
}
end.Lock()
_, err := unix.SendmsgN(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], end.dst6(), 0)
end.Unlock()
if err == nil {
return nil
}
// clear src and retry
if err == unix.EINVAL {
end.ClearSrc()
cmsg.pktinfo = unix.Inet6Pktinfo{}
end.Lock()
_, err = unix.SendmsgN(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], end.dst6(), 0)
end.Unlock()
}
return err
}
func receive4(sock int, buff []byte, end *NativeEndpoint) (int, error) {
// construct message header
var cmsg struct {
cmsghdr unix.Cmsghdr
pktinfo unix.Inet4Pktinfo
}
size, _, _, newDst, err := unix.Recvmsg(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], 0)
if err != nil {
return 0, err
}
end.isV6 = false
if newDst4, ok := newDst.(*unix.SockaddrInet4); ok {
*end.dst4() = *newDst4
}
// update source cache
if cmsg.cmsghdr.Level == unix.IPPROTO_IP &&
cmsg.cmsghdr.Type == unix.IP_PKTINFO &&
cmsg.cmsghdr.Len >= unix.SizeofInet4Pktinfo {
end.src4().Src = cmsg.pktinfo.Spec_dst
end.src4().Ifindex = cmsg.pktinfo.Ifindex
}
return size, nil
}
func receive6(sock int, buff []byte, end *NativeEndpoint) (int, error) {
// construct message header
var cmsg struct {
cmsghdr unix.Cmsghdr
pktinfo unix.Inet6Pktinfo
}
size, _, _, newDst, err := unix.Recvmsg(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], 0)
if err != nil {
return 0, err
}
end.isV6 = true
if newDst6, ok := newDst.(*unix.SockaddrInet6); ok {
*end.dst6() = *newDst6
}
// update source cache
if cmsg.cmsghdr.Level == unix.IPPROTO_IPV6 &&
cmsg.cmsghdr.Type == unix.IPV6_PKTINFO &&
cmsg.cmsghdr.Len >= unix.SizeofInet6Pktinfo {
end.src6().src = cmsg.pktinfo.Addr
end.dst6().ZoneId = cmsg.pktinfo.Ifindex
}
return size, nil
}