irnet_irda.c

linux-2.4.29操作系统的源码

/*
 *	IrNET protocol module : Synchronous PPP over an IrDA socket.
 *
 *		Jean II - HPL `00 - <[e-mail]>
 *
 * This file implement the IRDA interface of IrNET.
 * Basically, we sit on top of IrTTP. We set up IrTTP, IrIAS properly,
 * and exchange frames with IrTTP.
 */

#include "irnet_irda.h"		/* Private header */

/************************* CONTROL CHANNEL *************************/
/*
 * When ppp is not active, /dev/irnet act as a control channel.
 * Writting allow to set up the IrDA destination of the IrNET channel,
 * and any application may be read events happening on IrNET...
 */

/*------------------------------------------------------------------*/
/*
 * Post an event to the control channel...
 * Put the event in the log, and then wait all process blocked on read
 * so they can read the log...
 */
static void
irnet_post_event(irnet_socket *	ap,
		 irnet_event	event,
		 __u32		saddr,
		 __u32		daddr,
		 char *		name)
{
  unsigned long		flags;		/* For spinlock */
  int			index;		/* In the log */

  DENTER(CTRL_TRACE, "(ap=0x%X, event=%d, daddr=%08x, name=``%s'')\n",
	 (unsigned int) ap, event, daddr, name);

  /* Protect this section via spinlock.
   * Note : as we are the only event producer, we only need to exclude
   * ourself when touching the log, which is nice and easy.
   */
  spin_lock_irqsave(&irnet_events.spinlock, flags);

  /* Copy the event in the log */
  index = irnet_events.index;
  irnet_events.log[index].event = event;
  irnet_events.log[index].daddr = daddr;
  irnet_events.log[index].saddr = saddr;
  /* Try to copy IrDA nickname */
  if(name)
    strcpy(irnet_events.log[index].name, name);
  else
    irnet_events.log[index].name[0] = '\0';
  /* Try to get ppp unit number */
  if((ap != (irnet_socket *) NULL) && (ap->ppp_open))
    irnet_events.log[index].unit = ppp_unit_number(&ap->chan);
  else
    irnet_events.log[index].unit = -1;

  /* Increment the index
   * Note that we increment the index only after the event is written,
   * to make sure that the readers don't get garbage... */
  irnet_events.index = (index + 1) % IRNET_MAX_EVENTS;

  DEBUG(CTRL_INFO, "New event index is %d\n", irnet_events.index);

  /* Spin lock end */
  spin_unlock_irqrestore(&irnet_events.spinlock, flags);

  /* Now : wake up everybody waiting for events... */
  wake_up_interruptible_all(&irnet_events.rwait);

  DEXIT(CTRL_TRACE, "\n");
}

/************************* IRDA SUBROUTINES *************************/
/*
 * These are a bunch of subroutines called from other functions
 * down there, mostly common code or to improve readability...
 *
 * Note : we duplicate quite heavily some routines of af_irda.c,
 * because our input structure (self) is quite different
 * (struct irnet instead of struct irda_sock), which make sharing
 * the same code impossible (at least, without templates).
 */

/*------------------------------------------------------------------*/
/*
 * Function irda_open_tsap (self)
 *
 *    Open local Transport Service Access Point (TSAP)
 *
 * Create a IrTTP instance for us and set all the IrTTP callbacks.
 */
static inline int
irnet_open_tsap(irnet_socket *	self)
{
  notify_t	notify;		/* Callback structure */

  DENTER(IRDA_SR_TRACE, "(self=0x%X)\n", (unsigned int) self);

  DABORT(self->tsap != NULL, -EBUSY, IRDA_SR_ERROR, "Already busy !\n");

  /* Initialize IrTTP callbacks to be used by the IrDA stack */
  irda_notify_init(&notify);
  notify.connect_confirm	= irnet_connect_confirm;
  notify.connect_indication	= irnet_connect_indication;
  notify.disconnect_indication	= irnet_disconnect_indication;
  notify.data_indication	= irnet_data_indication;
  /*notify.udata_indication	= NULL;*/
  notify.flow_indication	= irnet_flow_indication;
  notify.status_indication	= irnet_status_indication;
  notify.instance		= self;
  strncpy(notify.name, IRNET_NOTIFY_NAME, NOTIFY_MAX_NAME);

  /* Open an IrTTP instance */
  self->tsap = irttp_open_tsap(LSAP_ANY, DEFAULT_INITIAL_CREDIT,
			       &notify);	
  DABORT(self->tsap == NULL, -ENOMEM,
	 IRDA_SR_ERROR, "Unable to allocate TSAP !\n");

  /* Remember which TSAP selector we actually got */
  self->stsap_sel = self->tsap->stsap_sel;

  DEXIT(IRDA_SR_TRACE, " - tsap=0x%X, sel=0x%X\n",
	(unsigned int) self->tsap, self->stsap_sel);
  return 0;
}

/*------------------------------------------------------------------*/
/*
 * Function irnet_ias_to_tsap (self, result, value)
 *
 *    Examine an IAS object and extract TSAP
 *
 * We do an IAP query to find the TSAP associated with the IrNET service.
 * When IrIAP pass us the result of the query, this function look at
 * the return values to check for failures and extract the TSAP if
 * possible.
 * Also deallocate value
 * The failure is in self->errno
 * Return TSAP or -1
 */
static inline __u8
irnet_ias_to_tsap(irnet_socket *	self,
		  int			result,
		  struct ias_value *	value)
{
  __u8	dtsap_sel = 0;		/* TSAP we are looking for */

  DENTER(IRDA_SR_TRACE, "(self=0x%X)\n", (unsigned int) self);

  /* By default, no error */
  self->errno = 0;

  /* Check if request succeeded */
  switch(result)
    {
      /* Standard errors : service not available */
    case IAS_CLASS_UNKNOWN:
    case IAS_ATTRIB_UNKNOWN:
      DEBUG(IRDA_SR_INFO, "IAS object doesn't exist ! (%d)\n", result);
      self->errno = -EADDRNOTAVAIL;
      break;

      /* Other errors, most likely IrDA stack failure */
    default :
      DEBUG(IRDA_SR_INFO, "IAS query failed ! (%d)\n", result);
      self->errno = -EHOSTUNREACH;
      break;

      /* Success : we got what we wanted */
    case IAS_SUCCESS:
      break;
    }

  /* Check what was returned to us */
  if(value != NULL)
    {
      /* What type of argument have we got ? */
      switch(value->type)
	{
	case IAS_INTEGER:
	  DEBUG(IRDA_SR_INFO, "result=%d\n", value->t.integer);
	  if(value->t.integer != -1)
	    /* Get the remote TSAP selector */
	    dtsap_sel = value->t.integer;
	  else 
	    self->errno = -EADDRNOTAVAIL;
	  break;
	default:
	  self->errno = -EADDRNOTAVAIL;
	  DERROR(IRDA_SR_ERROR, "bad type ! (0x%X)\n", value->type);
	  break;
	}

      /* Cleanup */
      irias_delete_value(value);
    }
  else	/* value == NULL */
    {
      /* Nothing returned to us - usually result != SUCCESS */
      if(!(self->errno))
	{
	  DERROR(IRDA_SR_ERROR,
		 "IrDA bug : result == SUCCESS && value == NULL\n");
	  self->errno = -EHOSTUNREACH;
	}
    }
  DEXIT(IRDA_SR_TRACE, "\n");

  /* Return the TSAP */
  return(dtsap_sel);
}

/*------------------------------------------------------------------*/
/*
 * Function irnet_find_lsap_sel (self)
 *
 *    Try to lookup LSAP selector in remote LM-IAS
 *
 * Basically, we start a IAP query, and then go to sleep. When the query
 * return, irnet_getvalue_confirm will wake us up, and we can examine the
 * result of the query...
 * Note that in some case, the query fail even before we go to sleep,
 * creating some races...
 */
static inline int
irnet_find_lsap_sel(irnet_socket *	self)
{
  DENTER(IRDA_SR_TRACE, "(self=0x%X)\n", (unsigned int) self);

  /* This should not happen */
  DABORT(self->iriap, -EBUSY, IRDA_SR_ERROR, "busy with a previous query.\n");

  /* Create an IAP instance, will be closed in irnet_getvalue_confirm() */
  self->iriap = iriap_open(LSAP_ANY, IAS_CLIENT, self,
			   irnet_getvalue_confirm);

  /* Treat unexpected signals as disconnect */
  self->errno = -EHOSTUNREACH;

  /* Query remote LM-IAS */
  iriap_getvaluebyclass_request(self->iriap, self->rsaddr, self->daddr,
				IRNET_SERVICE_NAME, IRNET_IAS_VALUE);

  /* The above request is non-blocking.
   * After a while, IrDA will call us back in irnet_getvalue_confirm()
   * We will then call irnet_ias_to_tsap() and finish the
   * connection procedure */

  DEXIT(IRDA_SR_TRACE, "\n");
  return 0;
}

/*------------------------------------------------------------------*/
/*
 * Function irnet_connect_tsap (self)
 *
 *    Initialise the TTP socket and initiate TTP connection
 *
 */
static inline int
irnet_connect_tsap(irnet_socket *	self)
{
  int		err;

  DENTER(IRDA_SR_TRACE, "(self=0x%X)\n", (unsigned int) self);

  /* Open a local TSAP (an IrTTP instance) */
  err = irnet_open_tsap(self);
  if(err != 0)
    {
      clear_bit(0, &self->ttp_connect);
      DERROR(IRDA_SR_ERROR, "connect aborted!\n");
      return(err);
    }

  /* Connect to remote device */
  err = irttp_connect_request(self->tsap, self->dtsap_sel, 
			      self->rsaddr, self->daddr, NULL, 
			      self->max_sdu_size_rx, NULL);
  if(err != 0)
    {
      clear_bit(0, &self->ttp_connect);
      DERROR(IRDA_SR_ERROR, "connect aborted!\n");
      return(err);
    }

  /* The above call is non-blocking.
   * After a while, the IrDA stack will either call us back in
   * irnet_connect_confirm() or irnet_disconnect_indication()
   * See you there ;-) */

  DEXIT(IRDA_SR_TRACE, "\n");
  return(err);
}

/*------------------------------------------------------------------*/
/*
 * Function irnet_discover_next_daddr (self)
 *
 *    Query the IrNET TSAP of the next device in the log.
 *
 * Used in the TSAP discovery procedure.
 */
static inline int
irnet_discover_next_daddr(irnet_socket *	self)
{
  /* Close the last instance of IrIAP, and open a new one.
   * We can't reuse the IrIAP instance in the IrIAP callback */
  if(self->iriap)
    {
      iriap_close(self->iriap);
      self->iriap = NULL;
    }
  /* Create a new IAP instance */
  self->iriap = iriap_open(LSAP_ANY, IAS_CLIENT, self,
			   irnet_discovervalue_confirm);

  /* Next discovery - before the call to avoid races */
  self->disco_index++;

  /* Check if we have one more address to try */
  if(self->disco_index < self->disco_number)
    {
      /* Query remote LM-IAS */
      iriap_getvaluebyclass_request(self->iriap,
				    self->discoveries[self->disco_index].saddr,
				    self->discoveries[self->disco_index].daddr,
				    IRNET_SERVICE_NAME, IRNET_IAS_VALUE);
      /* The above request is non-blocking.
       * After a while, IrDA will call us back in irnet_discovervalue_confirm()
       * We will then call irnet_ias_to_tsap() and come back here again... */
      return(0);
    }
  else
    return(1);
}

/*------------------------------------------------------------------*/
/*
 * Function irnet_discover_daddr_and_lsap_sel (self)
 *
 *    This try to find a device with the requested service.
 *
 * Initiate a TSAP discovery procedure.
 * It basically look into the discovery log. For each address in the list,
 * it queries the LM-IAS of the device to find if this device offer
 * the requested service.
 * If there is more than one node supporting the service, we complain
 * to the user (it should move devices around).
 * If we find one node which have the requested TSAP, we connect to it.
 *
 * This function just start the whole procedure. It request the discovery
 * log and submit the first IAS query.
 * The bulk of the job is handled in irnet_discovervalue_confirm()
 *
 * Note : this procedure fails if there is more than one device in range
 * on the same dongle, because IrLMP doesn't disconnect the LAP when the
 * last LSAP is closed. Moreover, we would need to wait the LAP
 * disconnection...
 */
static inline int
irnet_discover_daddr_and_lsap_sel(irnet_socket *	self)
{
  int	ret;

  DENTER(IRDA_SR_TRACE, "(self=0x%X)\n", (unsigned int) self);

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

  /* Check if the we got some results */
  if(self->discoveries == NULL)
    {
      self->disco_number = -1;
      clear_bit(0, &self->ttp_connect);
      DRETURN(-ENETUNREACH, IRDA_SR_INFO, "No Cachelog...\n");
    }
  DEBUG(IRDA_SR_INFO, "Got the log (0x%X), size is %d\n",
	(unsigned int) self->discoveries, self->disco_number);

  /* Start with the first discovery */
  self->disco_index = -1;
  self->daddr = DEV_ADDR_ANY;

  /* This will fail if the log is empty - this is non-blocking */
  ret = irnet_discover_next_daddr(self);
  if(ret)
    {
      /* Close IAP */
      iriap_close(self->iriap);
      self->iriap = NULL;

      /* Cleanup our copy of the discovery log */
      kfree(self->discoveries);
      self->discoveries = NULL;

      clear_bit(0, &self->ttp_connect);
      DRETURN(-ENETUNREACH, IRDA_SR_INFO, "Cachelog empty...\n");
    }

  /* Follow me in irnet_discovervalue_confirm() */

  DEXIT(IRDA_SR_TRACE, "\n");
  return(0);
}

/*------------------------------------------------------------------*/
/*
 * Function irnet_dname_to_daddr (self)
 *
 *    Convert an IrDA nickname to a valid IrDA address
 *
 * It basically look into the discovery log until there is a match.
 */
static inline int
irnet_dname_to_daddr(irnet_socket *	self)
{
  struct irda_device_info *discoveries;	/* Copy of the discovery log */
  int	number;			/* Number of nodes in the log */
  int	i;

  DENTER(IRDA_SR_TRACE, "(self=0x%X)\n", (unsigned int) self);

  /* Ask lmp for the current discovery log */
  discoveries = irlmp_get_discoveries(&number, 0xffff,
				      DISCOVERY_DEFAULT_SLOTS);
  /* Check if the we got some results */
  if(discoveries == NULL)
    DRETURN(-ENETUNREACH, IRDA_SR_INFO, "Cachelog empty...\n");

  /* 
   * Now, check all discovered devices (if any), and connect
   * client only about the services that the client is
   * interested in...
   */
  for(i = 0; i < number; i++)
    {
      /* Does the name match ? */
      if(!strncmp(discoveries[i].info, self->rname, NICKNAME_MAX_LEN))
	{
	  /* Yes !!! Get it.. */
	  self->daddr = discoveries[i].daddr;
	  DEBUG(IRDA_SR_INFO, "discovered device ``%s'' at address 0x%08x.\n",
		self->rname, self->daddr);
	  kfree(discoveries);
	  DEXIT(IRDA_SR_TRACE, "\n");
	  return 0;
	}
    }
  /* No luck ! */
  DEBUG(IRDA_SR_INFO, "cannot discover device ``%s'' !!!\n", self->rname);
  kfree(discoveries);
  return(-EADDRNOTAVAIL);
}


/************************* SOCKET ROUTINES *************************/
/*
 * This are the main operations on IrNET sockets, basically to create
 * and destroy IrNET sockets. These are called from the PPP part...
 */