af_irda.c

《嵌入式系统设计与实例开发实验教材二源码》Linux内核移植与编译实验

	/* Check if we have opened a local TSAP */
	if (!self->tsap)
		irda_open_tsap(self, LSAP_ANY, addr->sir_name);
	
	/* Move to connecting socket, start sending Connect Requests */
	sock->state = SS_CONNECTING;
	sk->state   = TCP_SYN_SENT;

	/* Connect to remote device */
	err = irttp_connect_request(self->tsap, self->dtsap_sel, 
				    self->saddr, self->daddr, NULL, 
				    self->max_sdu_size_rx, NULL);
	if (err) {
		IRDA_DEBUG(0, __FUNCTION__ "(), connect failed!\n");
		return err;
	}

	/* Now the loop */
	if (sk->state != TCP_ESTABLISHED && (flags & O_NONBLOCK))
		return -EINPROGRESS;
		
	cli();	/* To avoid races on the sleep */
	
	/* A Connect Ack with Choke or timeout or failed routing will go to
	 * closed.  */
	while (sk->state == TCP_SYN_SENT) {
		interruptible_sleep_on(sk->sleep);
		if (signal_pending(current)) {
			sti();
			return -ERESTARTSYS;
		}
	}
	
	if (sk->state != TCP_ESTABLISHED) {
		sti();
		sock->state = SS_UNCONNECTED;
		return sock_error(sk);	/* Always set at this point */
	}
	
	sock->state = SS_CONNECTED;
	
	sti();
	
	/* At this point, IrLMP has assigned our source address */
	self->saddr = irttp_get_saddr(self->tsap);

	return 0;
}

/*
 * Function irda_create (sock, protocol)
 *
 *    Create IrDA socket
 *
 */
static int irda_create(struct socket *sock, int protocol)
{
	struct sock *sk;
	struct irda_sock *self;

	IRDA_DEBUG(2, __FUNCTION__ "()\n");
	
	/* Check for valid socket type */
	switch (sock->type) {
	case SOCK_STREAM:     /* For TTP connections with SAR disabled */
	case SOCK_SEQPACKET:  /* For TTP connections with SAR enabled */
	case SOCK_DGRAM:      /* For TTP Unitdata or LMP Ultra transfers */
		break;
	default:
		return -ESOCKTNOSUPPORT;
	}

	/* Allocate networking socket */
	if ((sk = sk_alloc(PF_IRDA, GFP_ATOMIC, 1)) == NULL)
		return -ENOMEM;

	/* Allocate IrDA socket */
	self = kmalloc(sizeof(struct irda_sock), GFP_ATOMIC);
	if (self == NULL) {
		sk_free(sk);
		return -ENOMEM;
	}
	memset(self, 0, sizeof(struct irda_sock));

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

	init_waitqueue_head(&self->query_wait);

	/* Initialise networking socket struct */ 
	sock_init_data(sock, sk);	/* Note : set sk->refcnt to 1 */
	sk->family = PF_IRDA;
	sk->protocol = protocol;
	/* Link networking socket and IrDA socket structs together */
	sk->protinfo.irda = self;
	self->sk = sk;

	switch (sock->type) {
	case SOCK_STREAM:
		sock->ops = &irda_stream_ops;
		self->max_sdu_size_rx = TTP_SAR_DISABLE;
		break;
	case SOCK_SEQPACKET:
		sock->ops = &irda_seqpacket_ops;
		self->max_sdu_size_rx = TTP_SAR_UNBOUND;
		break;
	case SOCK_DGRAM:
		switch (protocol) {
#ifdef CONFIG_IRDA_ULTRA
		case IRDAPROTO_ULTRA:
			sock->ops = &irda_ultra_ops;
			break;
#endif /* CONFIG_IRDA_ULTRA */
		case IRDAPROTO_UNITDATA:
			sock->ops = &irda_dgram_ops;
			/* We let Unitdata conn. be like seqpack conn. */
			self->max_sdu_size_rx = TTP_SAR_UNBOUND;
			break;
		default:
			ERROR(__FUNCTION__ "(), protocol not supported!\n");
			return -ESOCKTNOSUPPORT;
		}
		break;
	default:
		return -ESOCKTNOSUPPORT;
	}		

	/* Register as a client with IrLMP */
	self->ckey = irlmp_register_client(0, NULL, NULL, NULL);
	self->mask = 0xffff;
	self->rx_flow = self->tx_flow = FLOW_START;
	self->nslots = DISCOVERY_DEFAULT_SLOTS;
	self->daddr = DEV_ADDR_ANY;	/* Until we get connected */
	self->saddr = 0x0;		/* so IrLMP assign us any link */

	MOD_INC_USE_COUNT;

	return 0;
}

/*
 * Function irda_destroy_socket (self)
 *
 *    Destroy socket
 *
 */
void irda_destroy_socket(struct irda_sock *self)
{
	IRDA_DEBUG(2, __FUNCTION__ "(%p)\n", self);

	ASSERT(self != NULL, return;);

	/* Unregister with IrLMP */
	irlmp_unregister_client(self->ckey);
	irlmp_unregister_service(self->skey);

	/* Unregister with LM-IAS */
	if (self->ias_obj) {
		irias_delete_object(self->ias_obj);
		self->ias_obj = NULL;
	}

	if (self->iriap) {
		iriap_close(self->iriap);
		self->iriap = NULL;
	}

	if (self->tsap) {
		irttp_disconnect_request(self->tsap, NULL, P_NORMAL);
		irttp_close_tsap(self->tsap);
		self->tsap = NULL;
	}
#ifdef CONFIG_IRDA_ULTRA
	if (self->lsap) {
		irlmp_close_lsap(self->lsap);
		self->lsap = NULL;
	}
#endif /* CONFIG_IRDA_ULTRA */
	kfree(self);
	MOD_DEC_USE_COUNT;

	return;
}

/*
 * Function irda_release (sock)
 *
 *    
 *
 */
static int irda_release(struct socket *sock)
{
	struct sock *sk = sock->sk;
	
	IRDA_DEBUG(2, __FUNCTION__ "()\n");

        if (sk == NULL) 
		return 0;
	
	sk->state       = TCP_CLOSE;
	sk->shutdown   |= SEND_SHUTDOWN;
	sk->state_change(sk);

	/* Destroy IrDA socket */
	irda_destroy_socket(sk->protinfo.irda);
	/* Prevent sock_def_destruct() to create havoc */
	sk->protinfo.irda = NULL;

	sock_orphan(sk);
	sock->sk   = NULL;      

	/* Purge queues (see sock_init_data()) */
	skb_queue_purge(&sk->receive_queue);

	/* Destroy networking socket if we are the last reference on it,
	 * i.e. if(sk->refcnt == 0) -> sk_free(sk) */
	sock_put(sk);

	/* Notes on socket locking and deallocation... - Jean II
	 * In theory we should put pairs of sock_hold() / sock_put() to
	 * prevent the socket to be destroyed whenever there is an
	 * outstanding request or outstanding incomming packet or event.
	 *
	 * 1) This may include IAS request, both in connect and getsockopt.
	 * Unfortunately, the situation is a bit more messy than it looks,
	 * because we close iriap and kfree(self) above.
	 * 
	 * 2) This may include selective discovery in getsockopt.
	 * Same stuff as above, irlmp registration and self are gone.
	 *
	 * Probably 1 and 2 may not matter, because it's all triggered
	 * by a process and the socket layer already prevent the
	 * socket to go away while a process is holding it, through
	 * sockfd_put() and fput()...
	 *
	 * 3) This may include deferred TSAP closure. In particular,
	 * we may receive a late irda_disconnect_indication()
	 * Fortunately, (tsap_cb *)->close_pend should protect us
	 * from that.
	 *
	 * I did some testing on SMP, and it looks solid. And the socket
	 * memory leak is now gone... - Jean II
	 */

        return 0;
}

/*
 * Function irda_sendmsg (sock, msg, len, scm)
 *
 *    Send message down to TinyTP. This function is used for both STREAM and
 *    SEQPACK services. This is possible since it forces the client to 
 *    fragment the message if necessary
 */
static int irda_sendmsg(struct socket *sock, struct msghdr *msg, int len, 
			struct scm_cookie *scm)
{
	struct sock *sk = sock->sk;
	struct irda_sock *self;
	struct sk_buff *skb;
	unsigned char *asmptr;
	int err;

	IRDA_DEBUG(4, __FUNCTION__ "(), len=%d\n", len);

	/* Note : socket.c set MSG_EOR on SEQPACKET sockets */
	if (msg->msg_flags & ~(MSG_DONTWAIT | MSG_EOR))
		return -EINVAL;

	if (sk->shutdown & SEND_SHUTDOWN) {
		send_sig(SIGPIPE, current, 0);
		return -EPIPE;
	}

	if (sk->state != TCP_ESTABLISHED)
		return -ENOTCONN;

	self = sk->protinfo.irda;
	ASSERT(self != NULL, return -1;);

	/* Check if IrTTP is wants us to slow down */
	while (self->tx_flow == FLOW_STOP) {
		IRDA_DEBUG(2, __FUNCTION__ "(), IrTTP is busy, going to sleep!\n");
		interruptible_sleep_on(sk->sleep);
		
		/* Check if we are still connected */
		if (sk->state != TCP_ESTABLISHED)
			return -ENOTCONN;
	}

	/* Check that we don't send out to big frames */
	if (len > self->max_data_size) {
		IRDA_DEBUG(2, __FUNCTION__ 
			   "(), Chopping frame from %d to %d bytes!\n", len, 
			   self->max_data_size);
		len = self->max_data_size;
	}

	skb = sock_alloc_send_skb(sk, len + self->max_header_size, 
				  msg->msg_flags & MSG_DONTWAIT, &err);
	if (!skb)
		return -ENOBUFS;

	skb_reserve(skb, self->max_header_size);
	
	asmptr = skb->h.raw = skb_put(skb, len);
	memcpy_fromiovec(asmptr, msg->msg_iov, len);

	/* 
	 * Just send the message to TinyTP, and let it deal with possible 
	 * errors. No need to duplicate all that here
	 */
	err = irttp_data_request(self->tsap, skb);
	if (err) {
		IRDA_DEBUG(0, __FUNCTION__ "(), err=%d\n", err);
		return err;
	}
	/* Tell client how much data we actually sent */
	return len;
}

/*
 * Function irda_recvmsg_dgram (sock, msg, size, flags, scm)
 *
 *    Try to receive message and copy it to user. The frame is discarded
 *    after being read, regardless of how much the user actually read
 */
static int irda_recvmsg_dgram(struct socket *sock, struct msghdr *msg, 
			      int size, int flags, struct scm_cookie *scm)
{
	struct irda_sock *self;
	struct sock *sk = sock->sk;
	struct sk_buff *skb;
	int copied, err;

	IRDA_DEBUG(4, __FUNCTION__ "()\n");

	self = sk->protinfo.irda;
	ASSERT(self != NULL, return -1;);

	skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT, 
				flags & MSG_DONTWAIT, &err);
	if (!skb)
		return err;

	skb->h.raw = skb->data;
	copied     = skb->len;
	
	if (copied > size) {
		IRDA_DEBUG(2, __FUNCTION__ 
			   "(), Received truncated frame (%d < %d)!\n",
			   copied, size);
		copied = size;
		msg->msg_flags |= MSG_TRUNC;
	}
	skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);

	skb_free_datagram(sk, skb);

	/*
	 *  Check if we have previously stopped IrTTP and we know
	 *  have more free space in our rx_queue. If so tell IrTTP
	 *  to start delivering frames again before our rx_queue gets
	 *  empty
	 */
	if (self->rx_flow == FLOW_STOP) {
		if ((atomic_read(&sk->rmem_alloc) << 2) <= sk->rcvbuf) {
			IRDA_DEBUG(2, __FUNCTION__ "(), Starting IrTTP\n");
			self->rx_flow = FLOW_START;
			irttp_flow_request(self->tsap, FLOW_START);
		}
	}

	return copied;
}

/*
 * Function irda_data_wait (sk)
 *
 *    Sleep until data has arrive. But check for races..
 *
 */
static void irda_data_wait(struct sock *sk)
{
	if (!skb_peek(&sk->receive_queue)) {
		set_bit(SOCK_ASYNC_WAITDATA, &sk->socket->flags);
		interruptible_sleep_on(sk->sleep);
		clear_bit(SOCK_ASYNC_WAITDATA, &sk->socket->flags);
	}
}

/*
 * Function irda_recvmsg_stream (sock, msg, size, flags, scm)
 *
 *    
 *
 */
static int irda_recvmsg_stream(struct socket *sock, struct msghdr *msg, 
			       int size, int flags, struct scm_cookie *scm)
{
	struct irda_sock *self;
	struct sock *sk = sock->sk;
	int noblock = flags & MSG_DONTWAIT;
	int copied = 0;
	int target = 1;

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

	self = sk->protinfo.irda;
	ASSERT(self != NULL, return -1;);

	if (sock->flags & __SO_ACCEPTCON) 
		return(-EINVAL);

	if (flags & MSG_OOB)
		return -EOPNOTSUPP;

	if (flags & MSG_WAITALL)
		target = size;
		
	msg->msg_namelen = 0;

	do {
		int chunk;
		struct sk_buff *skb;

		skb=skb_dequeue(&sk->receive_queue);
		if (skb==NULL) {
			if (copied >= target)
				break;
			
			/*
			 *	POSIX 1003.1g mandates this order.
			 */
			
			if (sk->err) {
				return sock_error(sk);
			}

			if (sk->shutdown & RCV_SHUTDOWN)
				break;

			if (noblock)
				return -EAGAIN;
			irda_data_wait(sk);
			if (signal_pending(current))
				return -ERESTARTSYS;
			continue;
		}

		chunk = min_t(unsigned int, skb->len, size);
		if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
			skb_queue_head(&sk->receive_queue, skb);
			if (copied == 0)
				copied = -EFAULT;
			break;
		}
		copied += chunk;
		size -= chunk;

		/* Mark read part of skb as used */
		if (!(flags & MSG_PEEK)) {
			skb_pull(skb, chunk);

			/* put the skb back if we didn't use it up.. */
			if (skb->len) {
				IRDA_DEBUG(1, __FUNCTION__ "(), back on q!\n");
				skb_queue_head(&sk->receive_queue, skb);
				break;
			}

			kfree_skb(skb);			
		} else {
			IRDA_DEBUG(0, __FUNCTION__ "() questionable!?\n");

			/* put message back and return */
			skb_queue_head(&sk->receive_queue, skb);
			break;
		}
	} while (size);

	/*
	 *  Check if we have previously stopped IrTTP and we know
	 *  have more free space in our rx_queue. If so tell IrTTP
	 *  to start delivering frames again before our rx_queue gets
	 *  empty
	 */
	if (self->rx_flow == FLOW_STOP) {
		if ((atomic_read(&sk->rmem_alloc) << 2) <= sk->rcvbuf) {
			IRDA_DEBUG(2, __FUNCTION__ "(), Starting IrTTP\n");
			self->rx_flow = FLOW_START;
			irttp_flow_request(self->tsap, FLOW_START);
		}
	}

	return copied;
}

/*
 * Function irda_sendmsg_dgram (sock, msg, len, scm)
 *
 *    Send message down to TinyTP for the unreliable sequenced
 *    packet service...