BadVPN – Rev 1
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/**
* @file BTap.c
* @author Ambroz Bizjak <ambrop7@gmail.com>
*
* @section LICENSE
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the author nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <string.h>
#include <stdio.h>
#ifdef BADVPN_USE_WINAPI
#include <windows.h>
#include <winioctl.h>
#include <objbase.h>
#include <wtypes.h>
#include "wintap-common.h"
#include <tuntap/tapwin32-funcs.h>
#else
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <net/if.h>
#include <net/if_arp.h>
#ifdef BADVPN_LINUX
#include <linux/if_tun.h>
#endif
#ifdef BADVPN_FREEBSD
#include <net/if_tun.h>
#include <net/if_tap.h>
#endif
#endif
#include <base/BLog.h>
#include <tuntap/BTap.h>
#include <generated/blog_channel_BTap.h>
static void report_error (BTap *o);
static void output_handler_recv (BTap *o, uint8_t *data);
#ifdef BADVPN_USE_WINAPI
static void recv_olap_handler (BTap *o, int event, DWORD bytes)
{
DebugObject_Access(&o->d_obj);
ASSERT(o->output_packet)
ASSERT(event == BREACTOR_IOCP_EVENT_SUCCEEDED || event == BREACTOR_IOCP_EVENT_FAILED)
// set no output packet
o->output_packet = NULL;
if (event == BREACTOR_IOCP_EVENT_FAILED) {
BLog(BLOG_ERROR, "read operation failed");
report_error(o);
return;
}
ASSERT(bytes >= 0)
ASSERT(bytes <= o->frame_mtu)
// done
PacketRecvInterface_Done(&o->output, bytes);
}
#else
static void fd_handler (BTap *o, int events)
{
DebugObject_Access(&o->d_obj);
DebugError_AssertNoError(&o->d_err);
if (events&(BREACTOR_ERROR|BREACTOR_HUP)) {
BLog(BLOG_WARNING, "device fd reports error?");
}
if (events&BREACTOR_READ) do {
ASSERT(o->output_packet)
// try reading into the buffer
int bytes = read(o->fd, o->output_packet, o->frame_mtu);
if (bytes <= 0) {
// Treat zero return value the same as EAGAIN.
// See: https://bugzilla.kernel.org/show_bug.cgi?id=96381
if (bytes == 0 || errno == EAGAIN || errno == EWOULDBLOCK) {
// retry later
break;
}
// report fatal error
report_error(o);
return;
}
ASSERT_FORCE(bytes <= o->frame_mtu)
// set no output packet
o->output_packet = NULL;
// update events
o->poll_events &= ~BREACTOR_READ;
BReactor_SetFileDescriptorEvents(o->reactor, &o->bfd, o->poll_events);
// inform receiver we finished the packet
PacketRecvInterface_Done(&o->output, bytes);
} while (0);
}
#endif
void report_error (BTap *o)
{
DEBUGERROR(&o->d_err, o->handler_error(o->handler_error_user));
}
void output_handler_recv (BTap *o, uint8_t *data)
{
DebugObject_Access(&o->d_obj);
DebugError_AssertNoError(&o->d_err);
ASSERT(data)
ASSERT(!o->output_packet)
#ifdef BADVPN_USE_WINAPI
memset(&o->recv_olap.olap, 0, sizeof(o->recv_olap.olap));
// read
BOOL res = ReadFile(o->device, data, o->frame_mtu, NULL, &o->recv_olap.olap);
if (res == FALSE && GetLastError() != ERROR_IO_PENDING) {
BLog(BLOG_ERROR, "ReadFile failed (%u)", GetLastError());
report_error(o);
return;
}
o->output_packet = data;
#else
// attempt read
int bytes = read(o->fd, data, o->frame_mtu);
if (bytes <= 0) {
if (bytes == 0 || errno == EAGAIN || errno == EWOULDBLOCK) {
// See note about zero return in fd_handler.
// retry later in fd_handler
// remember packet
o->output_packet = data;
// update events
o->poll_events |= BREACTOR_READ;
BReactor_SetFileDescriptorEvents(o->reactor, &o->bfd, o->poll_events);
return;
}
// report fatal error
report_error(o);
return;
}
ASSERT_FORCE(bytes <= o->frame_mtu)
PacketRecvInterface_Done(&o->output, bytes);
#endif
}
int BTap_Init (BTap *o, BReactor *reactor, char *devname, BTap_handler_error handler_error, void *handler_error_user, int tun)
{
ASSERT(tun == 0 || tun == 1)
struct BTap_init_data init_data;
init_data.dev_type = tun ? BTAP_DEV_TUN : BTAP_DEV_TAP;
init_data.init_type = BTAP_INIT_STRING;
init_data.init.string = devname;
return BTap_Init2(o, reactor, init_data, handler_error, handler_error_user);
}
int BTap_Init2 (BTap *o, BReactor *reactor, struct BTap_init_data init_data, BTap_handler_error handler_error, void *handler_error_user)
{
ASSERT(init_data.dev_type == BTAP_DEV_TUN || init_data.dev_type == BTAP_DEV_TAP)
// init arguments
o->reactor = reactor;
o->handler_error = handler_error;
o->handler_error_user = handler_error_user;
#ifdef BADVPN_USE_WINAPI
ASSERT(init_data.init_type == BTAP_INIT_STRING)
// parse device specification
if (!init_data.init.string) {
BLog(BLOG_ERROR, "no device specification provided");
goto fail0;
}
char *device_component_id;
char *device_name;
uint32_t tun_addrs[3];
if (init_data.dev_type == BTAP_DEV_TUN) {
if (!tapwin32_parse_tun_spec(init_data.init.string, &device_component_id, &device_name, tun_addrs)) {
BLog(BLOG_ERROR, "failed to parse TUN device specification");
goto fail0;
}
} else {
if (!tapwin32_parse_tap_spec(init_data.init.string, &device_component_id, &device_name)) {
BLog(BLOG_ERROR, "failed to parse TAP device specification");
goto fail0;
}
}
// locate device path
char device_path[TAPWIN32_MAX_REG_SIZE];
BLog(BLOG_INFO, "Looking for TAP-Win32 with component ID %s, name %s", device_component_id, device_name);
if (!tapwin32_find_device(device_component_id, device_name, &device_path)) {
BLog(BLOG_ERROR, "Could not find device");
goto fail1;
}
// open device
BLog(BLOG_INFO, "Opening device %s", device_path);
o->device = CreateFile(device_path, GENERIC_READ | GENERIC_WRITE, 0, 0, OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM|FILE_FLAG_OVERLAPPED, 0);
if (o->device == INVALID_HANDLE_VALUE) {
BLog(BLOG_ERROR, "CreateFile failed");
goto fail1;
}
// set TUN if needed
DWORD len;
if (init_data.dev_type == BTAP_DEV_TUN) {
if (!DeviceIoControl(o->device, TAP_IOCTL_CONFIG_TUN, tun_addrs, sizeof(tun_addrs), tun_addrs, sizeof(tun_addrs), &len, NULL)) {
BLog(BLOG_ERROR, "DeviceIoControl(TAP_IOCTL_CONFIG_TUN) failed");
goto fail2;
}
}
// get MTU
ULONG umtu = 0;
if (!DeviceIoControl(o->device, TAP_IOCTL_GET_MTU, &umtu, sizeof(umtu), &umtu, sizeof(umtu), &len, NULL)) {
BLog(BLOG_ERROR, "DeviceIoControl(TAP_IOCTL_GET_MTU) failed");
goto fail2;
}
if (init_data.dev_type == BTAP_DEV_TUN) {
o->frame_mtu = umtu;
} else {
o->frame_mtu = umtu + BTAP_ETHERNET_HEADER_LENGTH;
}
// set connected
ULONG upstatus = TRUE;
if (!DeviceIoControl(o->device, TAP_IOCTL_SET_MEDIA_STATUS, &upstatus, sizeof(upstatus), &upstatus, sizeof(upstatus), &len, NULL)) {
BLog(BLOG_ERROR, "DeviceIoControl(TAP_IOCTL_SET_MEDIA_STATUS) failed");
goto fail2;
}
BLog(BLOG_INFO, "Device opened");
// associate device with IOCP
if (!CreateIoCompletionPort(o->device, BReactor_GetIOCPHandle(o->reactor), 0, 0)) {
BLog(BLOG_ERROR, "CreateIoCompletionPort failed");
goto fail2;
}
// init send olap
BReactorIOCPOverlapped_Init(&o->send_olap, o->reactor, o, NULL);
// init recv olap
BReactorIOCPOverlapped_Init(&o->recv_olap, o->reactor, o, (BReactorIOCPOverlapped_handler)recv_olap_handler);
free(device_name);
free(device_component_id);
goto success;
fail2:
ASSERT_FORCE(CloseHandle(o->device))
fail1:
free(device_name);
free(device_component_id);
fail0:
return 0;
#endif
#if defined(BADVPN_LINUX) || defined(BADVPN_FREEBSD)
o->close_fd = (init_data.init_type != BTAP_INIT_FD);
switch (init_data.init_type) {
case BTAP_INIT_FD: {
ASSERT(init_data.init.fd.fd >= 0)
ASSERT(init_data.init.fd.mtu >= 0)
ASSERT(init_data.dev_type != BTAP_DEV_TAP || init_data.init.fd.mtu >= BTAP_ETHERNET_HEADER_LENGTH)
o->fd = init_data.init.fd.fd;
o->frame_mtu = init_data.init.fd.mtu;
} break;
case BTAP_INIT_STRING: {
char devname_real[IFNAMSIZ];
#ifdef BADVPN_LINUX
// open device
if ((o->fd = open("/dev/net/tun", O_RDWR)) < 0) {
BLog(BLOG_ERROR, "error opening device");
goto fail0;
}
// configure device
struct ifreq ifr;
memset(&ifr, 0, sizeof(ifr));
ifr.ifr_flags |= IFF_NO_PI;
if (init_data.dev_type == BTAP_DEV_TUN) {
ifr.ifr_flags |= IFF_TUN;
} else {
ifr.ifr_flags |= IFF_TAP;
}
if (init_data.init.string) {
snprintf(ifr.ifr_name, IFNAMSIZ, "%s", init_data.init.string);
}
if (ioctl(o->fd, TUNSETIFF, (void *)&ifr) < 0) {
BLog(BLOG_ERROR, "error configuring device");
goto fail1;
}
strcpy(devname_real, ifr.ifr_name);
#endif
#ifdef BADVPN_FREEBSD
if (init_data.dev_type == BTAP_DEV_TUN) {
BLog(BLOG_ERROR, "TUN not supported on FreeBSD");
goto fail0;
}
if (!init_data.init.string) {
BLog(BLOG_ERROR, "no device specified");
goto fail0;
}
// open device
char devnode[10 + IFNAMSIZ];
snprintf(devnode, sizeof(devnode), "/dev/%s", init_data.init.string);
if ((o->fd = open(devnode, O_RDWR)) < 0) {
BLog(BLOG_ERROR, "error opening device");
goto fail0;
}
// get name
struct ifreq ifr;
memset(&ifr, 0, sizeof(ifr));
if (ioctl(o->fd, TAPGIFNAME, (void *)&ifr) < 0) {
BLog(BLOG_ERROR, "error configuring device");
goto fail1;
}
strcpy(devname_real, ifr.ifr_name);
#endif
// get MTU
// open dummy socket for ioctls
int sock = socket(AF_INET, SOCK_DGRAM, 0);
if (sock < 0) {
BLog(BLOG_ERROR, "socket failed");
goto fail1;
}
memset(&ifr, 0, sizeof(ifr));
strcpy(ifr.ifr_name, devname_real);
if (ioctl(sock, SIOCGIFMTU, (void *)&ifr) < 0) {
BLog(BLOG_ERROR, "error getting MTU");
close(sock);
goto fail1;
}
if (init_data.dev_type == BTAP_DEV_TUN) {
o->frame_mtu = ifr.ifr_mtu;
} else {
o->frame_mtu = ifr.ifr_mtu + BTAP_ETHERNET_HEADER_LENGTH;
}
close(sock);
} break;
default: ASSERT(0);
}
// set non-blocking
if (fcntl(o->fd, F_SETFL, O_NONBLOCK) < 0) {
BLog(BLOG_ERROR, "cannot set non-blocking");
goto fail1;
}
// init file descriptor object
BFileDescriptor_Init(&o->bfd, o->fd, (BFileDescriptor_handler)fd_handler, o);
if (!BReactor_AddFileDescriptor(o->reactor, &o->bfd)) {
BLog(BLOG_ERROR, "BReactor_AddFileDescriptor failed");
goto fail1;
}
o->poll_events = 0;
goto success;
fail1:
if (o->close_fd) {
ASSERT_FORCE(close(o->fd) == 0)
}
fail0:
return 0;
#endif
success:
// init output
PacketRecvInterface_Init(&o->output, o->frame_mtu, (PacketRecvInterface_handler_recv)output_handler_recv, o, BReactor_PendingGroup(o->reactor));
// set no output packet
o->output_packet = NULL;
DebugError_Init(&o->d_err, BReactor_PendingGroup(o->reactor));
DebugObject_Init(&o->d_obj);
return 1;
}
void BTap_Free (BTap *o)
{
DebugObject_Free(&o->d_obj);
DebugError_Free(&o->d_err);
// free output
PacketRecvInterface_Free(&o->output);
#ifdef BADVPN_USE_WINAPI
// cancel I/O
ASSERT_FORCE(CancelIo(o->device))
// wait receiving to finish
if (o->output_packet) {
BLog(BLOG_DEBUG, "waiting for receiving to finish");
BReactorIOCPOverlapped_Wait(&o->recv_olap, NULL, NULL);
}
// free recv olap
BReactorIOCPOverlapped_Free(&o->recv_olap);
// free send olap
BReactorIOCPOverlapped_Free(&o->send_olap);
// close device
ASSERT_FORCE(CloseHandle(o->device))
#else
// free BFileDescriptor
BReactor_RemoveFileDescriptor(o->reactor, &o->bfd);
if (o->close_fd) {
// close file descriptor
ASSERT_FORCE(close(o->fd) == 0)
}
#endif
}
int BTap_GetMTU (BTap *o)
{
DebugObject_Access(&o->d_obj);
return o->frame_mtu;
}
void BTap_Send (BTap *o, uint8_t *data, int data_len)
{
DebugObject_Access(&o->d_obj);
DebugError_AssertNoError(&o->d_err);
ASSERT(data_len >= 0)
ASSERT(data_len <= o->frame_mtu)
#ifdef BADVPN_USE_WINAPI
// ignore frames without an Ethernet header, or we get errors in WriteFile
if (data_len < 14) {
return;
}
memset(&o->send_olap.olap, 0, sizeof(o->send_olap.olap));
// write
BOOL res = WriteFile(o->device, data, data_len, NULL, &o->send_olap.olap);
if (res == FALSE && GetLastError() != ERROR_IO_PENDING) {
BLog(BLOG_ERROR, "WriteFile failed (%u)", GetLastError());
return;
}
// wait
int succeeded;
DWORD bytes;
BReactorIOCPOverlapped_Wait(&o->send_olap, &succeeded, &bytes);
if (!succeeded) {
BLog(BLOG_ERROR, "write operation failed");
} else {
ASSERT(bytes >= 0)
ASSERT(bytes <= data_len)
if (bytes < data_len) {
BLog(BLOG_ERROR, "write operation didn't write everything");
}
}
#else
int bytes = write(o->fd, data, data_len);
if (bytes < 0) {
// malformed packets will cause errors, ignore them and act like
// the packet was accepeted
} else {
if (bytes != data_len) {
BLog(BLOG_WARNING, "written %d expected %d", bytes, data_len);
}
}
#endif
}
PacketRecvInterface * BTap_GetOutput (BTap *o)
{
DebugObject_Access(&o->d_obj);
return &o->output;
}