BadVPN – Rev 1
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/**
* @file BTap.h
* @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.
*
* @section DESCRIPTION
*
* TAP device abstraction.
*/
#ifndef BADVPN_TUNTAP_BTAP_H
#define BADVPN_TUNTAP_BTAP_H
#if (defined(BADVPN_USE_WINAPI) + defined(BADVPN_LINUX) + defined(BADVPN_FREEBSD)) != 1
#error Unknown TAP backend or too many TAP backends
#endif
#include <stdint.h>
#ifdef BADVPN_USE_WINAPI
#else
#include <net/if.h>
#endif
#include <misc/debug.h>
#include <misc/debugerror.h>
#include <base/DebugObject.h>
#include <system/BReactor.h>
#include <flow/PacketRecvInterface.h>
#define BTAP_ETHERNET_HEADER_LENGTH 14
/**
* Handler called when an error occurs on the device.
* The object must be destroyed from the job context of this
* handler, and no further I/O may occur.
*
* @param user as in {@link BTap_Init}
*/
typedef void (*BTap_handler_error) (void *used);
typedef struct {
BReactor *reactor;
BTap_handler_error handler_error;
void *handler_error_user;
int frame_mtu;
PacketRecvInterface output;
uint8_t *output_packet;
#ifdef BADVPN_USE_WINAPI
HANDLE device;
BReactorIOCPOverlapped send_olap;
BReactorIOCPOverlapped recv_olap;
#else
int close_fd;
int fd;
BFileDescriptor bfd;
int poll_events;
#endif
DebugError d_err;
DebugObject d_obj;
} BTap;
/**
* Initializes the TAP device.
*
* @param o the object
* @param BReactor {@link BReactor} we live in
* @param devname name of the devece to open.
* On Linux: a network interface name. If it is NULL, no
* specific device will be requested, and the operating system
* may create a new device.
* On Windows: a string "component_id:device_name", where
* component_id is a string identifying the driver, and device_name
* is the name of the network interface. If component_id is empty,
* a hardcoded default will be used instead. If device_name is empty,
* the first device found with a matching component_id will be used.
* Specifying a NULL devname is equivalent to specifying ":".
* @param handler_error error handler function
* @param handler_error_user value passed to error handler
* @param tun whether to create a TUN (IP) device or a TAP (Ethernet) device. Must be 0 or 1.
* @return 1 on success, 0 on failure
*/
int BTap_Init (BTap *o, BReactor *bsys, char *devname, BTap_handler_error handler_error, void *handler_error_user, int tun) WARN_UNUSED;
enum BTap_dev_type {BTAP_DEV_TUN, BTAP_DEV_TAP};
enum BTap_init_type {
BTAP_INIT_STRING,
#ifndef BADVPN_USE_WINAPI
BTAP_INIT_FD,
#endif
};
struct BTap_init_data {
enum BTap_dev_type dev_type;
enum BTap_init_type init_type;
union {
char *string;
struct {
int fd;
int mtu;
} fd;
} init;
};
/**
* Initializes the TAP device.
*
* @param o the object
* @param BReactor {@link BReactor} we live in
* @param init_data struct containing initialization parameters (to allow transparent passing).
* init.data.dev_type must be either BTAP_DEV_TUN for an IP device, or
* BTAP_DEV_TAP for an Ethernet device.
* init_data.init_type must be either BTAP_INIT_STRING or BTAP_INIT_FD.
* For BTAP_INIT_STRING, init_data.init.string specifies the TUN or TAP
* device, as described next.
* On Linux: a network interface name. If it is NULL, no
* specific device will be requested, and the operating system
* may create a new device.
* On Windows: a string "component_id:device_name", where
* component_id is a string identifying the driver, and device_name
* is the name of the network interface. If component_id is empty,
* a hardcoded default will be used instead. If device_name is empty,
* the first device found with a matching component_id will be used.
* Specifying NULL is equivalent to specifying ":".
* For BTAP_INIT_FD, the device is initialized using a file descriptor.
* In this case, init_data.init.fd.fd must be set to the file descriptor,
* and init_data.init.fd.mtu must be set to the largest IP packet or
* Ethernet frame supported, for a TUN or TAP device, respectively.
* File descriptor initialization is not supported on Windows.
* @param handler_error error handler function
* @param handler_error_user value passed to error handler
* @return 1 on success, 0 on failure
*/
int BTap_Init2 (BTap *o, BReactor *reactor, struct BTap_init_data init_data, BTap_handler_error handler_error, void *handler_error_user) WARN_UNUSED;
/**
* Frees the TAP device.
*
* @param o the object
*/
void BTap_Free (BTap *o);
/**
* Returns the device's maximum transmission unit (including any protocol headers).
*
* @param o the object
* @return device's MTU
*/
int BTap_GetMTU (BTap *o);
/**
* Sends a packet to the device.
* Any errors will be reported via a job.
*
* @param o the object
* @param data packet to send
* @param data_len length of packet. Must be >=0 and <=MTU, as reported by {@link BTap_GetMTU}.
*/
void BTap_Send (BTap *o, uint8_t *data, int data_len);
/**
* Returns a {@link PacketRecvInterface} for reading packets from the device.
* The MTU of the interface will be {@link BTap_GetMTU}.
*
* @param o the object
* @return output interface
*/
PacketRecvInterface * BTap_GetOutput (BTap *o);
#endif