irnet_irda.c

linux-2.4.29操作系统的源码

   * In fact, the situation is similar as JetSend overloading the Obex hint
   */
  hints = irlmp_service_to_hint(S_LAN);

#ifdef ADVERTISE_HINT
  /* Register with IrLMP as a service (advertise our hint bit) */
  irnet_server.skey = irlmp_register_service(hints);
#endif /* ADVERTISE_HINT */

  /* Register with LM-IAS (so that people can connect to us) */
  irnet_server.ias_obj = irias_new_object(IRNET_SERVICE_NAME, jiffies);
  irias_add_integer_attrib(irnet_server.ias_obj, IRNET_IAS_VALUE, 
			   irnet_server.s.stsap_sel, IAS_KERNEL_ATTR);
  irias_insert_object(irnet_server.ias_obj);

#ifdef DISCOVERY_EVENTS
  /* Tell IrLMP we want to be notified of newly discovered nodes */
  irlmp_update_client(irnet_server.s.ckey, hints,
		      irnet_discovery_indication, irnet_expiry_indication,
		      (void *) &irnet_server.s);
#endif

  DEXIT(IRDA_SERV_TRACE, " - self=0x%X\n", (unsigned int) &irnet_server.s);
  return 0;
}

/*------------------------------------------------------------------*/
/*
 * Function irda_destroy_server (self)
 *
 *    Destroy the IrTTP server...
 *
 * Reverse of the previous function...
 */
static inline void
irnet_destroy_server(void)
{
  DENTER(IRDA_SERV_TRACE, "()\n");

#ifdef ADVERTISE_HINT
  /* Unregister with IrLMP */
  irlmp_unregister_service(irnet_server.skey);
#endif /* ADVERTISE_HINT */

  /* Unregister with LM-IAS */
  if(irnet_server.ias_obj)
    irias_delete_object(irnet_server.ias_obj);

  /* Cleanup the socket part */
  irda_irnet_destroy(&irnet_server.s);

  DEXIT(IRDA_SERV_TRACE, "\n");
  return;
}


/************************ IRDA-TTP CALLBACKS ************************/
/*
 * When we create a IrTTP instance, we pass to it a set of callbacks
 * that IrTTP will call in case of various events.
 * We take care of those events here.
 */

/*------------------------------------------------------------------*/
/*
 * Function irnet_data_indication (instance, sap, skb)
 *
 *    Received some data from TinyTP. Just queue it on the receive queue
 *
 */
static int
irnet_data_indication(void *	instance,
		      void *	sap,
		      struct sk_buff *skb)
{
  irnet_socket *	ap = (irnet_socket *) instance;
  unsigned char *	p;
  int			code = 0;

  DENTER(IRDA_TCB_TRACE, "(self/ap=0x%X, skb=0x%X)\n",
	 (unsigned int) ap,(unsigned int) skb);
  DASSERT(skb != NULL, 0, IRDA_CB_ERROR, "skb is NULL !!!\n");

  /* Check is ppp is ready to receive our packet */
  if(!ap->ppp_open)
    {
      DERROR(IRDA_CB_ERROR, "PPP not ready, dropping packet...\n");
      /* When we return error, TTP will need to requeue the skb and
       * will stop the sender. IrTTP will stall until we send it a
       * flow control request... */
      return -ENOMEM;
    }

  /* strip address/control field if present */
  p = skb->data;
  if((p[0] == PPP_ALLSTATIONS) && (p[1] == PPP_UI))
    {
      /* chop off address/control */
      if(skb->len < 3)
	goto err_exit;
      p = skb_pull(skb, 2);
    }

  /* decompress protocol field if compressed */
  if(p[0] & 1)
    {
      /* protocol is compressed */
      skb_push(skb, 1)[0] = 0;
    }
  else
    if(skb->len < 2)
      goto err_exit;

  /* pass to generic ppp layer */
  /* Note : how do I know if ppp can accept or not the packet ? This is
   * essential if I want to manage flow control smoothly... */
  ppp_input(&ap->chan, skb);

  DEXIT(IRDA_TCB_TRACE, "\n");
  return 0;

 err_exit:
  DERROR(IRDA_CB_ERROR, "Packet too small, dropping...\n");
  kfree_skb(skb);
  ppp_input_error(&ap->chan, code);
  return 0;	/* Don't return an error code, only for flow control... */
}

/*------------------------------------------------------------------*/
/*
 * Function irnet_disconnect_indication (instance, sap, reason, skb)
 *
 *    Connection has been closed. Chech reason to find out why
 *
 * Note : there are many cases where we come here :
 *	o attempted to connect, timeout
 *	o connected, link is broken, LAP has timeout
 *	o connected, other side close the link
 *	o connection request on the server not handled
 */
static void
irnet_disconnect_indication(void *	instance,
			    void *	sap, 
			    LM_REASON	reason,
			    struct sk_buff *skb)
{
  irnet_socket *	self = (irnet_socket *) instance;
  int			test_open;
  int			test_connect;

  DENTER(IRDA_TCB_TRACE, "(self=0x%X)\n", (unsigned int) self);
  DASSERT(self != NULL, , IRDA_CB_ERROR, "Self is NULL !!!\n");

  /* Don't care about it, but let's not leak it */
  if(skb)
    dev_kfree_skb(skb);

  /* Prevent higher layer from accessing IrTTP */
  test_open = test_and_clear_bit(0, &self->ttp_open);
  /* Not connecting anymore...
   * (note : TSAP is open, so IAP callbacks are no longer pending...) */
  test_connect = test_and_clear_bit(0, &self->ttp_connect);

  /* If both self->ttp_open and self->ttp_connect are NULL, it mean that we
   * have a race condition with irda_irnet_destroy() or
   * irnet_connect_indication(), so don't mess up tsap...
   */
  if(!(test_open || test_connect))
    {
      DERROR(IRDA_CB_ERROR, "Race condition detected...\n");
      return;
    }

  /* If we were active, notify the control channel */
  if(test_open)
    irnet_post_event(self, IRNET_DISCONNECT_FROM,
		     self->saddr, self->daddr, self->rname);
  else
    /* If we were trying to connect, notify the control channel */
    if((self->tsap) && (self != &irnet_server.s))
      irnet_post_event(self, IRNET_NOANSWER_FROM,
		       self->saddr, self->daddr, self->rname);

  /* Close our IrTTP connection, cleanup tsap */
  if((self->tsap) && (self != &irnet_server.s))
    {
      DEBUG(IRDA_CB_INFO, "Closing our TTP connection.\n");
      irttp_close_tsap(self->tsap);
      self->tsap = NULL;
    }
  /* Cleanup the socket in case we want to reconnect in ppp_output_wakeup() */
  self->stsap_sel = 0;
  self->daddr = DEV_ADDR_ANY;
  self->tx_flow = FLOW_START;

  /* Deal with the ppp instance if it's still alive */
  if(self->ppp_open)
    {
      if(test_open)
	{
	  /* If we were connected, cleanup & close the PPP channel,
	   * which will kill pppd (hangup) and the rest */
	  ppp_unregister_channel(&self->chan);
	  self->ppp_open = 0;
	}
      else
	{
	  /* If we were trying to connect, flush (drain) ppp_generic
	   * Tx queue (most often we have blocked it), which will
	   * trigger an other attempt to connect. If we are passive,
	   * this will empty the Tx queue after last try. */
	  ppp_output_wakeup(&self->chan);
	}
    }

  DEXIT(IRDA_TCB_TRACE, "\n");
}

/*------------------------------------------------------------------*/
/*
 * Function irnet_connect_confirm (instance, sap, qos, max_sdu_size, skb)
 *
 *    Connections has been confirmed by the remote device
 *
 */
static void
irnet_connect_confirm(void *	instance,
		      void *	sap, 
		      struct qos_info *qos,
		      __u32	max_sdu_size,
		      __u8	max_header_size, 
		      struct sk_buff *skb)
{
  irnet_socket *	self = (irnet_socket *) instance;

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

  /* Check if socket is closing down (via irda_irnet_destroy()) */
  if(! test_bit(0, &self->ttp_connect))
    {
      DERROR(IRDA_CB_ERROR, "Socket no longer connecting. Ouch !\n");
      return;
    }

  /* How much header space do we need to reserve */
  self->max_header_size = max_header_size;

  /* IrTTP max SDU size in transmit direction */
  self->max_sdu_size_tx = max_sdu_size;
  self->max_data_size = max_sdu_size;
#ifdef STREAM_COMPAT
  if(max_sdu_size == 0)
    self->max_data_size = irttp_get_max_seg_size(self->tsap);
#endif /* STREAM_COMPAT */

  /* At this point, IrLMP has assigned our source address */
  self->saddr = irttp_get_saddr(self->tsap);

  /* Allow higher layer to access IrTTP */
  set_bit(0, &self->ttp_open);
  clear_bit(0, &self->ttp_connect);	/* Not racy, IrDA traffic is serial */
  /* Give a kick in the ass of ppp_generic so that he sends us some data */
  ppp_output_wakeup(&self->chan);

  /* Check size of received packet */
  if(skb->len > 0)
    {
#ifdef PASS_CONNECT_PACKETS
      DEBUG(IRDA_CB_INFO, "Passing connect packet to PPP.\n");
      /* Try to pass it to PPP */
      irnet_data_indication(instance, sap, skb);
#else /* PASS_CONNECT_PACKETS */
      DERROR(IRDA_CB_ERROR, "Dropping non empty packet.\n");
      kfree_skb(skb);	/* Note : will be optimised with other kfree... */
#endif /* PASS_CONNECT_PACKETS */
    }
  else
    kfree_skb(skb);

  /* Notify the control channel */
  irnet_post_event(self, IRNET_CONNECT_TO,
		   self->saddr, self->daddr, self->rname);

  DEXIT(IRDA_TCB_TRACE, "\n");
}

/*------------------------------------------------------------------*/
/*
 * Function irnet_flow_indication (instance, sap, flow)
 *
 *    Used by TinyTP to tell us if it can accept more data or not
 *
 */
static void
irnet_flow_indication(void *	instance,
		      void *	sap,
		      LOCAL_FLOW flow) 
{
  irnet_socket *	self = (irnet_socket *) instance;
  LOCAL_FLOW		oldflow = self->tx_flow;

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

  /* Update our state */
  self->tx_flow = flow;

  /* Check what IrTTP want us to do... */
  switch(flow)
    {
    case FLOW_START:
      DEBUG(IRDA_CB_INFO, "IrTTP wants us to start again\n");
      /* Check if we really need to wake up PPP */
      if(oldflow == FLOW_STOP)
	ppp_output_wakeup(&self->chan);
      else
	DEBUG(IRDA_CB_INFO, "But we were already transmitting !!!\n");
      break;
    case FLOW_STOP:
      DEBUG(IRDA_CB_INFO, "IrTTP wants us to slow down\n");
      break;
    default:
      DEBUG(IRDA_CB_INFO, "Unknown flow command!\n");
      break;
    }

  DEXIT(IRDA_TCB_TRACE, "\n");
}

/*------------------------------------------------------------------*/
/*
 * Function irnet_status_indication (instance, sap, reason, skb)
 *
 *    Link (IrLAP) status report.
 *
 */
static void
irnet_status_indication(void *	instance,
			LINK_STATUS link,
			LOCK_STATUS lock)
{
  irnet_socket *	self = (irnet_socket *) instance;

  DENTER(IRDA_TCB_TRACE, "(self=0x%X)\n", (unsigned int) self);
  DASSERT(self != NULL, , IRDA_CB_ERROR, "Self is NULL !!!\n");

  /* We can only get this event if we are connected */
  switch(link)
    {
    case STATUS_NO_ACTIVITY:
      irnet_post_event(self, IRNET_BLOCKED_LINK,
		       self->saddr, self->daddr, self->rname);
      break;
    default:
      DEBUG(IRDA_CB_INFO, "Unknown status...\n");
    }

  DEXIT(IRDA_TCB_TRACE, "\n");
}

/*------------------------------------------------------------------*/
/*
 * Function irnet_connect_indication(instance, sap, qos, max_sdu_size, userdata)
 *
 *    Incoming connection
 *
 * In theory, this function is called only on the server socket.
 * Some other node is attempting to connect to the IrNET service, and has
 * sent a connection request on our server socket.
 * We just redirect the connection to the relevant IrNET socket.
 * 
 * Note : we also make sure that between 2 irnet nodes, there can
 * exist only one irnet connection.
 */
static void
irnet_connect_indication(void *		instance,
			 void *		sap, 
			 struct qos_info *qos,
			 __u32		max_sdu_size,
			 __u8		max_header_size,
			 struct sk_buff *skb)
{
  irnet_socket *	server = &irnet_server.s;
  irnet_socket *	new = (irnet_socket *) NULL;

  DENTER(IRDA_TCB_TRACE, "(server=0x%X)\n", (unsigned int) server);
  DASSERT(instance == &irnet_server, , IRDA_CB_ERROR,
	  "Invalid instance (0x%X) !!!\n", (unsigned int) instance);
  DASSERT(sap == irnet_server.s.tsap, , IRDA_CB_ERROR, "Invalid sap !!!\n");

  /* Try to find the most appropriate IrNET socket */
  new = irnet_find_socket(server);

  /* After all this hard work, do we have an socket ? */
  if(new == (irnet_socket *) NULL)
    {
      DEXIT(IRDA_CB_INFO, ": No socket waiting for this connection.\n");
      irnet_disconnect_server(server, skb);
      return;
    }

  /* Is the socket already busy ? */
  if(test_bit(0, &new->ttp_open))
    {
      DEXIT(IRDA_CB_INFO, ": Socket already connected.\n");
      irnet_disconnect_server(server, skb);
      return;
    }

  /* The following code is a bit tricky, so need comments ;-)
   */
  /* If ttp_connect is set, the socket is trying to connect to the other
   * end and may have sent a IrTTP connection request and is waiting for
   * a connection response (that may never come).
   * Now, the pain is that the socket may have opened a tsap and is
   * waiting on it, while the other end is trying to connect to it on
   * another tsap.
   * Because IrNET can be peer to peer, we need to workaround this.
   * Furthermore, the way the irnetd script is implemented, the
   * target will create a second IrNET connection back to the
   * originator and expect the originator to bind this new connection
   * to the original PPPD instance.
   * And of course, if we don't use irnetd, we can have a race when
   * both side try to connect simultaneously, which could leave both
   * connections half closed (yuck).
   * Conclusions :
   *	1) The "originator" must accept the new connection and get rid
   *	   of the old one so that irnetd works
   *	2) One side must deny the new connection to avoid races,
   *	   but both side must agree on which side it is...
   * Most often, the originator is primary at the LAP layer.
   * Jean II
   */
  /* Now, let's look at the way I wrote the test...
   * We need to clear up the ttp_connect flag atomically to prevent
   * irnet_disconnect_indication() to mess up the tsap we are going to close.
   * We want to clear the ttp_connect flag only if we close the tsap,
   * otherwise we will never close it, so we need to check for primary
   * *before* doing the test on the flag.
   * And of course, ALLOW_SIMULT_CONNECT can disable this entirely...
   * Jean II
   */

  /* Socket already connecting ? On primary ? */
  if(0
#ifdef ALLOW_SIMULT_CONNECT
     || ((irttp_is_primary(server->tsap) == 1)	/* primary */
	 && (test_and_clear_bit(0, &new->ttp_connect)))
#endif /* ALLOW_SIMULT_CONNECT */
     )
    {
      DERROR(IRDA_CB_ERROR, "Socket already connecting, but going to reuse it !\n");

      /* Cleanup the old TSAP if necessary - IrIAP will be cleaned up later */
      if(new->tsap != NULL)
	{
	  /* Close the old connection the new socket was attempting,
	   * so that we can hook it up to the new connection.
	   * It's now safe to do it... */
	  irttp_close_tsap(new->tsap);
	  new->tsap = NULL;
	}
    }
  else
    {
      /* Three options :
       * 1) socket was not connecting or connected : ttp_connect should be 0.
       * 2) we don't want to connect the socket because we are secondary or