path: root/net/irda/irnet/irnet_ppp.c

/*
 *	IrNET protocol module : Synchronous PPP over an IrDA socket.
 *
 *		Jean II - HPL `00 - <jt@hpl.hp.com>
 *
 * This file implement the PPP interface and /dev/irnet character device.
 * The PPP interface hook to the ppp_generic module, handle all our
 *	relationship to the PPP code in the kernel (and by extension to pppd),
 *	and exchange PPP frames with this module (send/receive).
 * The /dev/irnet device is used primarily for 2 functions :
 *	1) as a stub for pppd (the ppp daemon), so that we can appropriately
 *	generate PPP sessions (we pretend we are a tty).
 *	2) as a control channel (write commands, read events)
 */

#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/smp_lock.h>
#include "irnet_ppp.h"		/* Private header */
/* Please put other headers in irnet.h - Thanks */

/* Generic PPP callbacks (to call us) */
static const struct ppp_channel_ops irnet_ppp_ops = {
	.start_xmit = ppp_irnet_send,
	.ioctl = ppp_irnet_ioctl
};

/************************* CONTROL CHANNEL *************************/
/*
 * When a pppd instance is not active on /dev/irnet, it acts as a control
 * channel.
 * Writing allow to set up the IrDA destination of the IrNET channel,
 * and any application may be read events happening in IrNET...
 */

/*------------------------------------------------------------------*/
/*
 * Write is used to send a command to configure a IrNET channel
 * before it is open by pppd. The syntax is : "command argument"
 * Currently there is only two defined commands :
 *	o name : set the requested IrDA nickname of the IrNET peer.
 *	o addr : set the requested IrDA address of the IrNET peer.
 * Note : the code is crude, but effective...
 */
static inline ssize_t
irnet_ctrl_write(irnet_socket *	ap,
		 const char __user *buf,
		 size_t		count)
{
  char		command[IRNET_MAX_COMMAND];
  char *	start;		/* Current command being processed */
  char *	next;		/* Next command to process */
  int		length;		/* Length of current command */

  DENTER(CTRL_TRACE, "(ap=0x%p, count=%Zd)\n", ap, count);

  /* Check for overflow... */
  DABORT(count >= IRNET_MAX_COMMAND, -ENOMEM,
	 CTRL_ERROR, "Too much data !!!\n");

  /* Get the data in the driver */
  if(copy_from_user(command, buf, count))
    {
      DERROR(CTRL_ERROR, "Invalid user space pointer.\n");
      return -EFAULT;
    }

  /* Safe terminate the string */
  command[count] = '\0';
  DEBUG(CTRL_INFO, "Command line received is ``%s'' (%Zd).\n",
	command, count);

  /* Check every commands in the command line */
  next = command;
  while(next != NULL)
    {
      /* Look at the next command */
      start = next;

	/* Scrap whitespaces before the command */
	start = skip_spaces(start);

      /* ',' is our command separator */
      next = strchr(start, ',');
      if(next)
	{
	  *next = '\0';			/* Terminate command */
	  length = next - start;	/* Length */
	  next++;			/* Skip the '\0' */
	}
      else
	length = strlen(start);

      DEBUG(CTRL_INFO, "Found command ``%s'' (%d).\n", start, length);

      /* Check if we recognised one of the known command
       * We can't use "switch" with strings, so hack with "continue" */

      /* First command : name -> Requested IrDA nickname */
      if(!strncmp(start, "name", 4))
	{
	  /* Copy the name only if is included and not "any" */
	  if((length > 5) && (strcmp(start + 5, "any")))
	    {
	      /* Strip out trailing whitespaces */
	      while(isspace(start[length - 1]))
		length--;

	      /* Copy the name for later reuse */
	      memcpy(ap->rname, start + 5, length - 5);
	      ap->rname[length - 5] = '\0';
	    }
	  else
	    ap->rname[0] = '\0';
	  DEBUG(CTRL_INFO, "Got rname = ``%s''\n", ap->rname);

	  /* Restart the loop */
	  continue;
	}

      /* Second command : addr, daddr -> Requested IrDA destination address
       * Also process : saddr -> Requested IrDA source address */
      if((!strncmp(start, "addr", 4