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-rw-r--r--conn/conn_linux.go573
1 files changed, 573 insertions, 0 deletions
diff --git a/conn/conn_linux.go b/conn/conn_linux.go
new file mode 100644
index 0000000..a4fa389
--- /dev/null
+++ b/conn/conn_linux.go
@@ -0,0 +1,573 @@
+// +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, device interface{}) (*nativeBind, 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
+}