irnet_ppp.c

linux-2.6.15.6

/*
 *	IrNET protocol module : Synchronous PPP over an IrDA socket.
 *
 *		Jean II - HPL `00 - <[e-mail]>
 *
 * 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 "irnet_ppp.h"		/* Private header */
/* Please put other headers in irnet.h - Thanks */

/* Generic PPP callbacks (to call us) */
static 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 */
      while(isspace(*start))
	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)) ||
	 (!strncmp(start, "daddr", 5)) ||
	 (!strncmp(start, "saddr", 5)))
	{
	  __u32		addr = DEV_ADDR_ANY;

	  /* Copy the address only if is included and not "any" */
	  if((length > 5) && (strcmp(start + 5, "any")))
	    {
	      char *	begp = start + 5;
	      char *	endp;

	      /* Scrap whitespaces before the command */
	      while(isspace(*begp))
		begp++;

	      /* Convert argument to a number (last arg is the base) */
	      addr = simple_strtoul(begp, &endp, 16);
	      /* Has it worked  ? (endp should be start + length) */
	      DABORT(endp <= (start + 5), -EINVAL,
		     CTRL_ERROR, "Invalid address.\n");
	    }
	  /* Which type of address ? */
	  if(start[0] == 's')
	    {
	      /* Save it */
	      ap->rsaddr = addr;
	      DEBUG(CTRL_INFO, "Got rsaddr = %08x\n", ap->rsaddr);
	    }
	  else
	    {
	      /* Save it */
	      ap->rdaddr = addr;
	      DEBUG(CTRL_INFO, "Got rdaddr = %08x\n", ap->rdaddr);
	    }

	  /* Restart the loop */
	  continue;
	}

      /* Other possible command : connect N (number of retries) */

      /* No command matched -> Failed... */
      DABORT(1, -EINVAL, CTRL_ERROR, "Not a recognised IrNET command.\n");
    }

  /* Success : we have parsed all commands successfully */
  return(count);
}

#ifdef INITIAL_DISCOVERY
/*------------------------------------------------------------------*/
/*
 * Function irnet_get_discovery_log (self)
 *
 *    Query the content on the discovery log if not done
 *
 * This function query the current content of the discovery log
 * at the startup of the event channel and save it in the internal struct.
 */
static void
irnet_get_discovery_log(irnet_socket *	ap)
{
  __u16		mask = irlmp_service_to_hint(S_LAN);

  /* Ask IrLMP for the current discovery log */
  ap->discoveries = irlmp_get_discoveries(&ap->disco_number, mask,
					  DISCOVERY_DEFAULT_SLOTS);

  /* Check if the we got some results */
  if(ap->discoveries == NULL)
    ap->disco_number = -1;

  DEBUG(CTRL_INFO, "Got the log (0x%p), size is %d\n",
	ap->discoveries, ap->disco_number);
}

/*------------------------------------------------------------------*/
/*
 * Function irnet_read_discovery_log (self, event)
 *
 *    Read the content on the discovery log
 *
 * This function dump the current content of the discovery log
 * at the startup of the event channel.
 * Return 1 if wrote an event on the control channel...
 *
 * State of the ap->disco_XXX variables :
 * Socket creation :  discoveries = NULL ; disco_index = 0 ; disco_number = 0
 * While reading :    discoveries = ptr  ; disco_index = X ; disco_number = Y
 * After reading :    discoveries = NULL ; disco_index = Y ; disco_number = -1
 */
static inline int
irnet_read_discovery_log(irnet_socket *	ap,
			 char *		event)
{
  int		done_event = 0;

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

  /* Test if we have some work to do or we have already finished */
  if(ap->disco_number == -1)
    {
      DEBUG(CTRL_INFO, "Already done\n");
      return 0;
    }

  /* Test if it's the first time and therefore we need to get the log */
  if(ap->discoveries == NULL)
    irnet_get_discovery_log(ap);

  /* Check if we have more item to dump */
  if(ap->disco_index < ap->disco_number)
    {
      /* Write an event */
      sprintf(event, "Found %08x (%s) behind %08x {hints %02X-%02X}\n",
	      ap->discoveries[ap->disco_index].daddr,
	      ap->discoveries[ap->disco_index].info,
	      ap->discoveries[ap->disco_index].saddr,
	      ap->discoveries[ap->disco_index].hints[0],
	      ap->discoveries[ap->disco_index].hints[1]);
      DEBUG(CTRL_INFO, "Writing discovery %d : %s\n",
	    ap->disco_index, ap->discoveries[ap->disco_index].info);

      /* We have an event */
      done_event = 1;
      /* Next discovery */
      ap->disco_index++;
    }

  /* Check if we have done the last item */
  if(ap->disco_index >= ap->disco_number)
    {
      /* No more items : remove the log and signal termination */
      DEBUG(CTRL_INFO, "Cleaning up log (0x%p)\n",
	    ap->discoveries);
      if(ap->discoveries != NULL)
	{
	  /* Cleanup our copy of the discovery log */
	  kfree(ap->discoveries);
	  ap->discoveries = NULL;
	}
      ap->disco_number = -1;
    }

  return done_event;
}
#endif /* INITIAL_DISCOVERY */

/*------------------------------------------------------------------*/
/*
 * Read is used to get IrNET events
 */
static inline ssize_t
irnet_ctrl_read(irnet_socket *	ap,
		struct file *	file,
		char __user *	buf,
		size_t		count)
{
  DECLARE_WAITQUEUE(wait, current);
  char		event[64];	/* Max event is 61 char */
  ssize_t	ret = 0;

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

  /* Check if we can write an event out in one go */
  DABORT(count < sizeof(event), -EOVERFLOW, CTRL_ERROR, "Buffer to small.\n");

#ifdef INITIAL_DISCOVERY
  /* Check if we have read the log */
  if(irnet_read_discovery_log(ap, event))
    {
      /* We have an event !!! Copy it to the user */
      if(copy_to_user(buf, event, strlen(event)))
	{
	  DERROR(CTRL_ERROR, "Invalid user space pointer.\n");
	  return -EFAULT;
	}

      DEXIT(CTRL_TRACE, "\n");
      return(strlen(event));
    }
#endif /* INITIAL_DISCOVERY */

  /* Put ourselves on the wait queue to be woken up */
  add_wait_queue(&irnet_events.rwait, &wait);
  current->state = TASK_INTERRUPTIBLE;
  for(;;)
    {
      /* If there is unread events */
      ret = 0;
      if(ap->event_index != irnet_events.index)
	break;
      ret = -EAGAIN;
      if(file->f_flags & O_NONBLOCK)
	break;
      ret = -ERESTARTSYS;
      if(signal_pending(current))
	break;
      /* Yield and wait to be woken up */
      schedule();
    }
  current->state = TASK_RUNNING;
  remove_wait_queue(&irnet_events.rwait, &wait);

  /* Did we got it ? */
  if(ret != 0)
    {
      /* No, return the error code */
      DEXIT(CTRL_TRACE, " - ret %Zd\n", ret);
      return ret;
    }

  /* Which event is it ? */
  switch(irnet_events.log[ap->event_index].event)
    {
    case IRNET_DISCOVER:
      sprintf(event, "Discovered %08x (%s) behind %08x {hints %02X-%02X}\n",
	      irnet_events.log[ap->event_index].daddr,
	      irnet_events.log[ap->event_index].name,
	      irnet_events.log[ap->event_index].saddr,
	      irnet_events.log[ap->event_index].hints.byte[0],
	      irnet_events.log[ap->event_index].hints.byte[1]);
      break;
    case IRNET_EXPIRE:
      sprintf(event, "Expired %08x (%s) behind %08x {hints %02X-%02X}\n",
	      irnet_events.log[ap->event_index].daddr,
	      irnet_events.log[ap->event_index].name,
	      irnet_events.log[ap->event_index].saddr,
	      irnet_events.log[ap->event_index].hints.byte[0],
	      irnet_events.log[ap->event_index].hints.byte[1]);
      break;
    case IRNET_CONNECT_TO:
      sprintf(event, "Connected to %08x (%s) on ppp%d\n",
	      irnet_events.log[ap->event_index].daddr,
	      irnet_events.log[ap->event_index].name,
	      irnet_events.log[ap->event_index].unit);
      break;
    case IRNET_CONNECT_FROM:
      sprintf(event, "Connection from %08x (%s) on ppp%d\n",
	      irnet_events.log[ap->event_index].daddr,
	      irnet_events.log[ap->event_index].name,
	      irnet_events.log[ap->event_index].unit);
      break;
    case IRNET_REQUEST_FROM:
      sprintf(event, "Request from %08x (%s) behind %08x\n",
	      irnet_events.log[ap->event_index].daddr,
	      irnet_events.log[ap->event_index].name,
	      irnet_events.log[ap->event_index].saddr);
      break;
    case IRNET_NOANSWER_FROM:
      sprintf(event, "No-answer from %08x (%s) on ppp%d\n",
	      irnet_events.log[ap->event_index].daddr,
	      irnet_events.log[ap->event_index].name,
	      irnet_events.log[ap->event_index].unit);
      break;
    case IRNET_BLOCKED_LINK:
      sprintf(event, "Blocked link with %08x (%s) on ppp%d\n",
	      irnet_events.log[ap->event_index].daddr,
	      irnet_events.log[ap->event_index].name,