tuntap.h

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/*
 * Copyright (c) 2012 Tristan Le Guern <leguern AT medu DOT se>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/types.h>
#if defined Windows
# include <In6addr.h>
#else /* Unix */
# include <sys/socket.h>
#endif

#if !defined Windows /* Unix :) */
# if defined __linux__
#  include <linux/if.h>
# else
#  include <net/if.h>
# endif
# include <netinet/in.h>
# include <netinet/if_ether.h>
#endif

#include <stdint.h>

#ifndef LIBTUNTAP_H_
# define LIBTUNTAP_H_

/*
 * Uniformize macros
 * - ETHER_ADDR_LEN: Magic number from IEEE 802.3
 * - IF_NAMESIZE: Length of interface external name
 * - IF_DESCRSIZE: Length of interface description
 * - TUNSDEBUG: ioctl flag to enable the debug mode of a tun device
 * - TUNFD_INVALID_VALUE: Invalid value for tun_fd
 */
# if defined ETH_ALEN /* Linux */
#  define ETHER_ADDR_LEN ETH_ALEN
# elif defined Windows
#  define ETHER_ADDR_LEN 6 
# endif

# if defined IFNAMSIZ && !defined IF_NAMESIZE
#  define IF_NAMESIZE IFNAMSIZ /* Historical BSD name */
# elif !defined IF_NAMESIZE
#  define IF_NAMESIZE 16
# endif

# define IF_DESCRSIZE 50 /* XXX: Tests needed on NetBSD and OpenBSD */

# if defined TUNSETDEBUG
#  define TUNSDEBUG TUNSETDEBUG
# endif

# if defined Windows
#  define TUNFD_INVALID_VALUE INVALID_HANDLE_VALUE
# else /* Unix */
#  define TUNFD_INVALID_VALUE -1
# endif

/*
 * Uniformize types
 * - t_tun: tun device file descriptor
 * - t_tun_in_addr: struct in_addr/IN_ADDR
 * - t_tun_in6_addr: struct in6_addr/IN6_ADDR
 */
# if defined Windows
typedef HANDLE t_tun;
typedef IN_ADDR t_tun_in_addr;
typedef IN6_ADDR t_tun_in6_addr;
# else /* Unix */
typedef int t_tun;
typedef struct in_addr t_tun_in_addr;
typedef struct in6_addr t_tun_in6_addr;
# endif

/*
 * Windows helpers
 */
# if defined Windows
#  define snprintf(x, y, z, ...) _snprintf_s((x), (y), (y), (z), __VA_ARGS__);
#  define strncat(x, y, z) strncat_s((x), _countof(x), (y), (z));
#  define strdup(x) _strdup(x)
# endif

# define TUNTAP_ID_MAX 256
# define TUNTAP_ID_ANY 257

# define TUNTAP_MODE_ETHERNET 0x0001
# define TUNTAP_MODE_TUNNEL   0x0002
# define TUNTAP_MODE_PERSIST  0x0004

# define TUNTAP_LOG_NONE      0x0000
# define TUNTAP_LOG_DEBUG     0x0001
# define TUNTAP_LOG_INFO      0x0002
# define TUNTAP_LOG_NOTICE    0x0004
# define TUNTAP_LOG_WARN      0x0008
# define TUNTAP_LOG_ERR       0x0016

/* Versioning: 0xMMmm, with 'M' for major and 'm' for minor */
# define TUNTAP_VERSION_MAJOR 0
# define TUNTAP_VERSION_MINOR 3
# define TUNTAP_VERSION ((TUNTAP_VERSION_MAJOR<<8)|TUNTAP_VERSION_MINOR)

# define TUNTAP_GET_FD(x) (x)->tun_fd

/* Handle Windows symbols export */
# if defined Windows 
#  if defined(tuntap_EXPORTS) /* CMake generated goo */
#   define  TUNTAP_EXPORT __declspec(dllexport)
#  else
#   define  TUNTAP_EXPORT __declspec(dllimport)
#  endif
# else /* Unix */
#  define TUNTAP_EXPORT
# endif

# ifdef __cplusplus
extern "C" {
# endif

struct device {
        t_tun                   tun_fd;
        int                             ctrl_sock;
        int                             flags;     /* ifr.ifr_flags on Unix */
        unsigned char   hwaddr[ETHER_ADDR_LEN];
        char                    if_name[IF_NAMESIZE];
};

/* User definable log callback */
typedef void (*t_tuntap_log)(int, const char *);
TUNTAP_EXPORT t_tuntap_log tuntap_log;

/* Portable "public" functions */
TUNTAP_EXPORT struct device     *tuntap_init(void);
TUNTAP_EXPORT int                tuntap_version(void);
TUNTAP_EXPORT void               tuntap_destroy(struct device *);
TUNTAP_EXPORT void               tuntap_release(struct device *);
TUNTAP_EXPORT int                tuntap_start(struct device *, int, int);
TUNTAP_EXPORT char              *tuntap_get_ifname(struct device *);
TUNTAP_EXPORT int                tuntap_set_ifname(struct device *, const char *);
TUNTAP_EXPORT char              *tuntap_get_hwaddr(struct device *);
TUNTAP_EXPORT int                tuntap_set_hwaddr(struct device *, const char *);
TUNTAP_EXPORT int                tuntap_set_descr(struct device *, const char *);
TUNTAP_EXPORT int                tuntap_up(struct device *);
TUNTAP_EXPORT int                tuntap_down(struct device *);
TUNTAP_EXPORT int                tuntap_get_mtu(struct device *);
TUNTAP_EXPORT int                tuntap_set_mtu(struct device *, int);
TUNTAP_EXPORT int                tuntap_set_ip(struct device *, const char *, int);
TUNTAP_EXPORT int                tuntap_read(struct device *, void *, size_t);
TUNTAP_EXPORT int                tuntap_write(struct device *, void *, size_t);
TUNTAP_EXPORT int                tuntap_get_readable(struct device *);
TUNTAP_EXPORT int                tuntap_set_nonblocking(struct device *dev, int);
TUNTAP_EXPORT int                tuntap_set_debug(struct device *dev, int);

/* Logging functions */
TUNTAP_EXPORT void               tuntap_log_set_cb(t_tuntap_log cb);
void             tuntap_log_default(int, const char *);
void             tuntap_log_hexdump(void *, size_t);
void             tuntap_log_chksum(void *, int);

/* OS specific functions */
int              tuntap_sys_start(struct device *, int, int);
void     tuntap_sys_destroy(struct device *);
int              tuntap_sys_set_hwaddr(struct device *, struct ether_addr *);
int              tuntap_sys_set_ipv4(struct device *, t_tun_in_addr *, uint32_t);
int              tuntap_sys_set_ipv6(struct device *, t_tun_in6_addr *, uint32_t);
int              tuntap_sys_set_ifname(struct device *, const char *, size_t);
int              tuntap_sys_set_descr(struct device *, const char *, size_t);

# ifdef __cplusplus
}
# endif

#endif