af_irda.c

linux 内核源代码

/*********************************************************************
 *
 * Filename:      af_irda.c
 * Version:       0.9
 * Description:   IrDA sockets implementation
 * Status:        Stable
 * Author:        Dag Brattli <[e-mail]>
 * Created at:    Sun May 31 10:12:43 1998
 * Modified at:   Sat Dec 25 21:10:23 1999
 * Modified by:   Dag Brattli <[e-mail]>
 * Sources:       af_netroom.c, af_ax25.c, af_rose.c, af_x25.c etc.
 *
 *     Copyright (c) 1999 Dag Brattli <[e-mail]>
 *     Copyright (c) 1999-2003 Jean Tourrilhes <[e-mail]>
 *     All Rights Reserved.
 *
 *     This program is free software; you can redistribute it and/or
 *     modify it under the terms of the GNU General Public License as
 *     published by the Free Software Foundation; either version 2 of
 *     the License, or (at your option) any later version.
 *
 *     This program is distributed in the hope that it will be useful,
 *     but WITHOUT ANY WARRANTY; without even the implied warranty of
 *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 *     GNU General Public License for more details.
 *
 *     You should have received a copy of the GNU General Public License
 *     along with this program; if not, write to the Free Software
 *     Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 *     MA 02111-1307 USA
 *
 *     Linux-IrDA now supports four different types of IrDA sockets:
 *
 *     o SOCK_STREAM:    TinyTP connections with SAR disabled. The
 *                       max SDU size is 0 for conn. of this type
 *     o SOCK_SEQPACKET: TinyTP connections with SAR enabled. TTP may
 *                       fragment the messages, but will preserve
 *                       the message boundaries
 *     o SOCK_DGRAM:     IRDAPROTO_UNITDATA: TinyTP connections with Unitdata
 *                       (unreliable) transfers
 *                       IRDAPROTO_ULTRA: Connectionless and unreliable data
 *
 ********************************************************************/

#include <linux/capability.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/init.h>
#include <linux/net.h>
#include <linux/irda.h>
#include <linux/poll.h>

#include <asm/ioctls.h>		/* TIOCOUTQ, TIOCINQ */
#include <asm/uaccess.h>

#include <net/sock.h>
#include <net/tcp_states.h>

#include <net/irda/af_irda.h>

static int irda_create(struct net *net, struct socket *sock, int protocol);

static const struct proto_ops irda_stream_ops;
static const struct proto_ops irda_seqpacket_ops;
static const struct proto_ops irda_dgram_ops;

#ifdef CONFIG_IRDA_ULTRA
static const struct proto_ops irda_ultra_ops;
#define ULTRA_MAX_DATA 382
#endif /* CONFIG_IRDA_ULTRA */

#define IRDA_MAX_HEADER (TTP_MAX_HEADER)

/*
 * Function irda_data_indication (instance, sap, skb)
 *
 *    Received some data from TinyTP. Just queue it on the receive queue
 *
 */
static int irda_data_indication(void *instance, void *sap, struct sk_buff *skb)
{
	struct irda_sock *self;
	struct sock *sk;
	int err;

	IRDA_DEBUG(3, "%s()\n", __FUNCTION__);

	self = instance;
	sk = instance;

	err = sock_queue_rcv_skb(sk, skb);
	if (err) {
		IRDA_DEBUG(1, "%s(), error: no more mem!\n", __FUNCTION__);
		self->rx_flow = FLOW_STOP;

		/* When we return error, TTP will need to requeue the skb */
		return err;
	}

	return 0;
}

/*
 * Function irda_disconnect_indication (instance, sap, reason, skb)
 *
 *    Connection has been closed. Check reason to find out why
 *
 */
static void irda_disconnect_indication(void *instance, void *sap,
				       LM_REASON reason, struct sk_buff *skb)
{
	struct irda_sock *self;
	struct sock *sk;

	self = instance;

	IRDA_DEBUG(2, "%s(%p)\n", __FUNCTION__, self);

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

	sk = instance;
	if (sk == NULL) {
		IRDA_DEBUG(0, "%s(%p) : BUG : sk is NULL\n",
			   __FUNCTION__, self);
		return;
	}

	/* Prevent race conditions with irda_release() and irda_shutdown() */
	bh_lock_sock(sk);
	if (!sock_flag(sk, SOCK_DEAD) && sk->sk_state != TCP_CLOSE) {
		sk->sk_state     = TCP_CLOSE;
		sk->sk_shutdown |= SEND_SHUTDOWN;

		sk->sk_state_change(sk);

		/* Close our TSAP.
		 * If we leave it open, IrLMP put it back into the list of
		 * unconnected LSAPs. The problem is that any incoming request
		 * can then be matched to this socket (and it will be, because
		 * it is at the head of the list). This would prevent any
		 * listening socket waiting on the same TSAP to get those
		 * requests. Some apps forget to close sockets, or hang to it
		 * a bit too long, so we may stay in this dead state long
		 * enough to be noticed...
		 * Note : all socket function do check sk->sk_state, so we are
		 * safe...
		 * Jean II
		 */
		if (self->tsap) {
			irttp_close_tsap(self->tsap);
			self->tsap = NULL;
		}
	}
	bh_unlock_sock(sk);

	/* Note : once we are there, there is not much you want to do
	 * with the socket anymore, apart from closing it.
	 * For example, bind() and connect() won't reset sk->sk_err,
	 * sk->sk_shutdown and sk->sk_flags to valid values...
	 * Jean II
	 */
}

/*
 * Function irda_connect_confirm (instance, sap, qos, max_sdu_size, skb)
 *
 *    Connections has been confirmed by the remote device
 *
 */
static void irda_connect_confirm(void *instance, void *sap,
				 struct qos_info *qos,
				 __u32 max_sdu_size, __u8 max_header_size,
				 struct sk_buff *skb)
{
	struct irda_sock *self;
	struct sock *sk;

	self = instance;

	IRDA_DEBUG(2, "%s(%p)\n", __FUNCTION__, self);

	sk = instance;
	if (sk == NULL) {
		dev_kfree_skb(skb);
		return;
	}

	dev_kfree_skb(skb);
	// Should be ??? skb_queue_tail(&sk->sk_receive_queue, skb);

	/* 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;

	/* Find out what the largest chunk of data that we can transmit is */
	switch (sk->sk_type) {
	case SOCK_STREAM:
		if (max_sdu_size != 0) {
			IRDA_ERROR("%s: max_sdu_size must be 0\n",
				   __FUNCTION__);
			return;
		}
		self->max_data_size = irttp_get_max_seg_size(self->tsap);
		break;
	case SOCK_SEQPACKET:
		if (max_sdu_size == 0) {
			IRDA_ERROR("%s: max_sdu_size cannot be 0\n",
				   __FUNCTION__);
			return;
		}
		self->max_data_size = max_sdu_size;
		break;
	default:
		self->max_data_size = irttp_get_max_seg_size(self->tsap);
	}

	IRDA_DEBUG(2, "%s(), max_data_size=%d\n", __FUNCTION__,
		   self->max_data_size);

	memcpy(&self->qos_tx, qos, sizeof(struct qos_info));

	/* We are now connected! */
	sk->sk_state = TCP_ESTABLISHED;
	sk->sk_state_change(sk);
}

/*
 * Function irda_connect_indication(instance, sap, qos, max_sdu_size, userdata)
 *
 *    Incoming connection
 *
 */
static void irda_connect_indication(void *instance, void *sap,
				    struct qos_info *qos, __u32 max_sdu_size,
				    __u8 max_header_size, struct sk_buff *skb)
{
	struct irda_sock *self;
	struct sock *sk;

	self = instance;

	IRDA_DEBUG(2, "%s(%p)\n", __FUNCTION__, self);

	sk = instance;
	if (sk == NULL) {
		dev_kfree_skb(skb);
		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;

	/* Find out what the largest chunk of data that we can transmit is */
	switch (sk->sk_type) {
	case SOCK_STREAM:
		if (max_sdu_size != 0) {
			IRDA_ERROR("%s: max_sdu_size must be 0\n",
				   __FUNCTION__);
			kfree_skb(skb);
			return;
		}
		self->max_data_size = irttp_get_max_seg_size(self->tsap);
		break;
	case SOCK_SEQPACKET:
		if (max_sdu_size == 0) {
			IRDA_ERROR("%s: max_sdu_size cannot be 0\n",
				   __FUNCTION__);
			kfree_skb(skb);
			return;
		}
		self->max_data_size = max_sdu_size;
		break;
	default:
		self->max_data_size = irttp_get_max_seg_size(self->tsap);
	}

	IRDA_DEBUG(2, "%s(), max_data_size=%d\n", __FUNCTION__,
		   self->max_data_size);

	memcpy(&self->qos_tx, qos, sizeof(struct qos_info));

	skb_queue_tail(&sk->sk_receive_queue, skb);
	sk->sk_state_change(sk);
}

/*
 * Function irda_connect_response (handle)
 *
 *    Accept incoming connection
 *
 */
static void irda_connect_response(struct irda_sock *self)
{
	struct sk_buff *skb;

	IRDA_DEBUG(2, "%s()\n", __FUNCTION__);

	skb = alloc_skb(TTP_MAX_HEADER + TTP_SAR_HEADER,
			GFP_ATOMIC);
	if (skb == NULL) {
		IRDA_DEBUG(0, "%s() Unable to allocate sk_buff!\n",
			   __FUNCTION__);
		return;
	}

	/* Reserve space for MUX_CONTROL and LAP header */
	skb_reserve(skb, IRDA_MAX_HEADER);

	irttp_connect_response(self->tsap, self->max_sdu_size_rx, skb);
}

/*
 * Function irda_flow_indication (instance, sap, flow)
 *
 *    Used by TinyTP to tell us if it can accept more data or not
 *
 */
static void irda_flow_indication(void *instance, void *sap, LOCAL_FLOW flow)
{
	struct irda_sock *self;
	struct sock *sk;

	IRDA_DEBUG(2, "%s()\n", __FUNCTION__);

	self = instance;
	sk = instance;
	BUG_ON(sk == NULL);

	switch (flow) {
	case FLOW_STOP:
		IRDA_DEBUG(1, "%s(), IrTTP wants us to slow down\n",
			   __FUNCTION__);
		self->tx_flow = flow;
		break;
	case FLOW_START:
		self->tx_flow = flow;
		IRDA_DEBUG(1, "%s(), IrTTP wants us to start again\n",
			   __FUNCTION__);
		wake_up_interruptible(sk->sk_sleep);
		break;
	default:
		IRDA_DEBUG(0, "%s(), Unknown flow command!\n", __FUNCTION__);
		/* Unknown flow command, better stop */
		self->tx_flow = flow;
		break;
	}
}

/*
 * Function irda_getvalue_confirm (obj_id, value, priv)
 *
 *    Got answer from remote LM-IAS, just pass object to requester...
 *
 * Note : duplicate from above, but we need our own version that
 * doesn't touch the dtsap_sel and save the full value structure...
 */
static void irda_getvalue_confirm(int result, __u16 obj_id,
				  struct ias_value *value, void *priv)
{
	struct irda_sock *self;

	self = (struct irda_sock *) priv;
	if (!self) {
		IRDA_WARNING("%s: lost myself!\n", __FUNCTION__);
		return;
	}

	IRDA_DEBUG(2, "%s(%p)\n", __FUNCTION__, self);

	/* We probably don't need to make any more queries */
	iriap_close(self->iriap);
	self->iriap = NULL;

	/* Check if request succeeded */
	if (result != IAS_SUCCESS) {
		IRDA_DEBUG(1, "%s(), IAS query failed! (%d)\n", __FUNCTION__,
			   result);

		self->errno = result;	/* We really need it later */

		/* Wake up any processes waiting for result */
		wake_up_interruptible(&self->query_wait);

		return;
	}

	/* Pass the object to the caller (so the caller must delete it) */
	self->ias_result = value;
	self->errno = 0;

	/* Wake up any processes waiting for result */
	wake_up_interruptible(&self->query_wait);
}

/*
 * Function irda_selective_discovery_indication (discovery)
 *
 *    Got a selective discovery indication from IrLMP.
 *
 * IrLMP is telling us that this node is new and matching our hint bit
 * filter. Wake up any process waiting for answer...
 */
static void irda_selective_discovery_indication(discinfo_t *discovery,
						DISCOVERY_MODE mode,
						void *priv)
{
	struct irda_sock *self;

	IRDA_DEBUG(2, "%s()\n", __FUNCTION__);

	self = (struct irda_sock *) priv;
	if (!self) {
		IRDA_WARNING("%s: lost myself!\n", __FUNCTION__);
		return;
	}

	/* Pass parameter to the caller */
	self->cachedaddr = discovery->daddr;

	/* Wake up process if its waiting for device to be discovered */
	wake_up_interruptible(&self->query_wait);
}

/*
 * Function irda_discovery_timeout (priv)
 *
 *    Timeout in the selective discovery process
 *
 * We were waiting for a node to be discovered, but nothing has come up
 * so far. Wake up the user and tell him that we failed...
 */
static void irda_discovery_timeout(u_long priv)
{
	struct irda_sock *self;

	IRDA_DEBUG(2, "%s()\n", __FUNCTION__);

	self = (struct irda_sock *) priv;
	BUG_ON(self == NULL);

	/* Nothing for the caller */
	self->cachelog = NULL;
	self->cachedaddr = 0;
	self->errno = -ETIME;

	/* Wake up process if its still waiting... */
	wake_up_interruptible(&self->query_wait);
}

/*
 * Function irda_open_tsap (self)
 *
 *    Open local Transport Service Access Point (TSAP)
 *
 */
static int irda_open_tsap(struct irda_sock *self, __u8 tsap_sel, char *name)
{
	notify_t notify;

	if (self->tsap) {
		IRDA_WARNING("%s: busy!\n", __FUNCTION__);
		return -EBUSY;
	}

	/* Initialize callbacks to be used by the IrDA stack */
	irda_notify_init(&notify);
	notify.connect_confirm       = irda_connect_confirm;
	notify.connect_indication    = irda_connect_indication;
	notify.disconnect_indication = irda_disconnect_indication;
	notify.data_indication       = irda_data_indication;
	notify.udata_indication	     = irda_data_indication;
	notify.flow_indication       = irda_flow_indication;
	notify.instance = self;
	strncpy(notify.name, name, NOTIFY_MAX_NAME);

	self->tsap = irttp_open_tsap(tsap_sel, DEFAULT_INITIAL_CREDIT,
				     &notify);
	if (self->tsap == NULL) {
		IRDA_DEBUG(0, "%s(), Unable to allocate TSAP!\n",
			   __FUNCTION__);
		return -ENOMEM;
	}
	/* Remember which TSAP selector we actually got */
	self->stsap_sel = self->tsap->stsap_sel;

	return 0;
}