nuttx/arch/sim/src/up_tapdev.c

/****************************************************************************
 * up_tapdev.c
 *
 *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
 *
 * Based on code from uIP which also has a BSD-like license:
 *
 *   Copyright (c) 2001, Adam Dunkels.
 *   All rights reserved.
 *
 * 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 NuttX 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
 * COPYRIGHT OWNER OR CONTRIBUTORS 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.
 *
 ****************************************************************************/

#ifdef linux

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/uio.h>
#include <sys/socket.h>

#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>

#include <linux/if.h>
#include <linux/if_tun.h>
#include <linux/net.h>

extern int lib_rawprintf(const char *format, ...);

/****************************************************************************
 * Private Definitions
 ****************************************************************************/

#define TAPDEV_DEBUG    1

#define DEVTAP          "/dev/net/tun"

#ifndef CONFIG_EXAMPLE_UIP_DHCPC
#  define UIP_IPADDR0   192
#  define UIP_IPADDR1   168
#  define UIP_IPADDR2   0
#  define UIP_IPADDR3   128
#else
#  define UIP_IPADDR0   0
#  define UIP_IPADDR1   0
#  define UIP_IPADDR2   0
#  define UIP_IPADDR3   0
#endif

#define READ            3
#define WRITE           4
#define OPEN            5
#define IOCTL           54
#define SELECT          82
#define SOCKETCALL      102

/****************************************************************************
 * Private Types
 ****************************************************************************/

/* Warning: This is very much Linux version specific! */

struct sel_arg_struct
{
  unsigned long   n;
  fd_set         *inp;
  fd_set         *outp;
  fd_set         *exp;
  struct timeval *tvp;
};

/****************************************************************************
 * Private Function Prototypes
 ****************************************************************************/

/****************************************************************************
 * Private Data
 ****************************************************************************/

#ifdef TAPDEV_DEBUG
static int gdrop = 0;
#endif
static int gtapdevfd;

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/* This is REALLY awkward.. we need to compile using the system header files,
 * but we can't use any of the libc calls because all of the symbols are
 * defined for NuttX (read, write, etc)!  So we do hand rolled syscalls
 * to get to the Linux functions.
 */

static inline int up_open(const char *filename, int flags, int mode)
{
  int result;

  __asm__ volatile ("int $0x80" \
                    : "=a" (result) \
                    : "0" (OPEN), "b" ((int)(filename)), "c" ((int)(flags)), "d" ((int)(mode)) \
                    : "memory");

  return (int)result;
}

static inline int up_socketcall(int call, unsigned long *args)
{
  int result;

  __asm__ volatile ("int $0x80" \
                    : "=a" (result) \
                    : "0" (SOCKETCALL), "b" (call), "c" ((int)args)	\
                    : "memory");

  return (int)result;
}

static inline int up_socket(int domain, int type, int protocol)
{
  unsigned long args[3];
  args[0] = domain;
  args[1] = type;
  args[2] = protocol;
  return up_socketcall(SYS_SOCKET, args);  
}

static inline int up_read(int fd, void* buf, size_t count)
{
  ssize_t result;

  __asm__ volatile ("int $0x80" \
                    : "=a" (result) \
                    : "0" (READ), "b" ((int)(fd)), "c" ((int)(buf)), "d" ((int)(count)) \
                    : "memory");

  return (int)result;
}

static inline int up_write(int fd, const void* buf, size_t count)
{
  ssize_t result;

  __asm__ volatile ("int $0x80" \
                    : "=a" (result) \
                    : "0" (WRITE), "b" ((int)(fd)), "c" ((int)(buf)), "d" ((int)(count)) \
                    : "memory");

  return (int)result;
}

static inline int up_ioctl(int fd, unsigned int cmd, unsigned long arg)
{
  ssize_t result;

  __asm__ volatile ("int $0x80" \
                    : "=a" (result) \
                    : "0" (IOCTL), "b" ((int)(fd)), "c" ((int)(cmd)), "d" ((long)(arg)) \
                    : "memory");

  return (int)result;
}

static inline int up_select(struct sel_arg_struct *arg)
{
  ssize_t result;

  __asm__ volatile ("int $0x80" \
                    : "=a" (result) \
                    : "0" (SELECT),"b" ((struct sel_arg_struct *)(arg))
                    : "memory");

  return (int)result;
}

#ifdef TAPDEV_DEBUG
static inline void dump_ethhdr(const char *msg, unsigned char *buf, int buflen)
{
  lib_rawprintf("TAPDEV: %s %d bytes\n", msg, buflen);
  lib_rawprintf("        %02x:%02x:%02x:%02x:%02x:%02x %02x:%02x:%02x:%02x:%02x:%02x %02x%02x\n",
                buf[0], buf[1], buf[2], buf[3], buf[4],  buf[5],
                buf[6], buf[7], buf[8], buf[9], buf[10], buf[11],
#if UIP_BYTE_ORDER == UIP_LITTLE_ENDIAN
                buf[12], buf[13]);
#else
                buf[13], buf[12]);
#endif
}
#else
#  define dump_ethhdr(m,b,l)
#endif

/****************************************************************************
 * Public Functions
 ****************************************************************************/

unsigned long up_getwalltime( void )
{
  struct timeval tm;
  (void)gettimeofday(&tm, NULL);
  return tm.tv_sec*1000 + tm.tv_usec/1000;
}

void tapdev_init(void)
{
  struct ifreq ifr;
  char buf[1024];
  int ret;

  /* Open the tap device */

  gtapdevfd = up_open(DEVTAP, O_RDWR, 0644);
  if (gtapdevfd < 0)
    {
      lib_rawprintf("TAPDEV: open failed: %d\n", -gtapdevfd );
      return;
    }

  /* Configure the tap device */

  memset(&ifr, 0, sizeof(ifr));
  ifr.ifr_flags = IFF_TAP|IFF_NO_PI;
  ret = up_ioctl(gtapdevfd, TUNSETIFF, (unsigned long) &ifr);
  if (ret < 0)
    {
      lib_rawprintf("TAPDEV: ioctl failed: %d\n", -ret );
      return;
   }

  /* Assign an IPv4 address to the tap device */

  snprintf(buf, sizeof(buf), "/sbin/ifconfig tap0 inet %d.%d.%d.%d\n",
           UIP_IPADDR0, UIP_IPADDR1, UIP_IPADDR2, UIP_IPADDR3);
  system(buf);
}

int tapdev_getmacaddr(unsigned char *macaddr)
{
  int ret = -1;
  if (macaddr)
    {
      /* Get a socket (only so that we get access to the INET subsystem) */

      int sockfd = up_socket(PF_INET, SOCK_DGRAM, 0);
      if (sockfd >= 0)
        {
          struct ifreq req;
          memset (&req, 0, sizeof(struct ifreq));

          /* Put the driver name into the request */

          strncpy(req.ifr_name, "tap0", IFNAMSIZ);

          /* Perform the ioctl to get the MAC address */

          ret = up_ioctl(sockfd, SIOCGIFHWADDR, (unsigned long)&req);
          if (!ret)
            {
              /* Return the MAC address */

              memcpy(macaddr, &req.ifr_hwaddr.sa_data, IFHWADDRLEN);
            }
        }
    }
  return ret;
}

unsigned int tapdev_read(unsigned char *buf, unsigned int buflen)
{
  struct sel_arg_struct arg;
  fd_set                fdset;
  struct timeval        tv;
  int                   ret;

  /* We can't do anything if we failed to open the tap device */

  if (gtapdevfd < 0)
    {
      return 0;
    }

  /* Wait for data on the tap device (or a timeout) */

  tv.tv_sec  = 0;
  tv.tv_usec = 1000;

  FD_ZERO(&fdset);
  FD_SET(gtapdevfd, &fdset);

  arg.n    = gtapdevfd + 1;
  arg.inp  = &fdset;
  arg.outp = NULL;
  arg.exp  = NULL;
  arg.tvp  = &tv;

  ret = up_select(&arg);
  if(ret == 0)
    {
      return 0;
    }

  ret = up_read(gtapdevfd, buf, buflen);
  if (ret < 0)
    {
      lib_rawprintf("TAPDEV: read failed: %d\n", -ret);
      return 0;
    }

  dump_ethhdr("read", buf, ret);
  return ret;
}

void tapdev_send(unsigned char *buf, unsigned int buflen)
{
  int ret;
#ifdef TAPDEV_DEBUG
  lib_rawprintf("tapdev_send: sending %d bytes\n", buflen);

  gdrop++;
  if(gdrop % 8 == 7)
    {
      lib_rawprintf("Dropped a packet!\n");
      return;
    }
#endif

  ret = up_write(gtapdevfd, buf, buflen);
  if (ret < 0)
    {
      lib_rawprintf("TAPDEV: write failed: %d", -ret);
      exit(1);
    }
  dump_ethhdr("write", buf, buflen);
}

#endif /* linux */