diff options
Diffstat (limited to 'conn/conn_linux.go')
| -rw-r--r-- | conn/conn_linux.go | 571 |
1 files changed, 571 insertions, 0 deletions
diff --git a/conn/conn_linux.go b/conn/conn_linux.go new file mode 100644 index 0000000..523da4a --- /dev/null +++ b/conn/conn_linux.go @@ -0,0 +1,571 @@ +// +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 +} |