af_irda.c

linux 内核源代码

		/* If we don't have a valid service name, we assume the
		 * user want to connect on a specific LSAP. Prevent
		 * the use of invalid LSAPs (IrLMP 1.1 p10). Jean II */
		if((addr->sir_name[0] != '\0') ||
		   (addr->sir_lsap_sel >= 0x70)) {
			/* Query remote LM-IAS using service name */
			err = irda_find_lsap_sel(self, addr->sir_name);
			if (err) {
				IRDA_DEBUG(0, "%s(), connect failed!\n", __FUNCTION__);
				return err;
			}
		} else {
			/* Directly connect to the remote LSAP
			 * specified by the sir_lsap field.
			 * Please use with caution, in IrDA LSAPs are
			 * dynamic and there is no "well-known" LSAP. */
			self->dtsap_sel = addr->sir_lsap_sel;
		}
	}

	/* 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->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, "%s(), connect failed!\n", __FUNCTION__);
		return err;
	}

	/* Now the loop */
	if (sk->sk_state != TCP_ESTABLISHED && (flags & O_NONBLOCK))
		return -EINPROGRESS;

	if (wait_event_interruptible(*(sk->sk_sleep),
				     (sk->sk_state != TCP_SYN_SENT)))
		return -ERESTARTSYS;

	if (sk->sk_state != TCP_ESTABLISHED) {
		sock->state = SS_UNCONNECTED;
		err = sock_error(sk);
		return err? err : -ECONNRESET;
	}

	sock->state = SS_CONNECTED;

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

	return 0;
}

static struct proto irda_proto = {
	.name	  = "IRDA",
	.owner	  = THIS_MODULE,
	.obj_size = sizeof(struct irda_sock),
};

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

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

	if (net != &init_net)
		return -EAFNOSUPPORT;

	/* 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 */
	sk = sk_alloc(net, PF_IRDA, GFP_ATOMIC, &irda_proto);
	if (sk == NULL)
		return -ENOMEM;

	self = irda_sk(sk);
	IRDA_DEBUG(2, "%s() : self is %p\n", __FUNCTION__, self);

	init_waitqueue_head(&self->query_wait);

	/* Initialise networking socket struct */
	sock_init_data(sock, sk);	/* Note : set sk->sk_refcnt to 1 */
	sk->sk_family = PF_IRDA;
	sk->sk_protocol = protocol;

	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;
			/* Initialise now, because we may send on unbound
			 * sockets. Jean II */
			self->max_data_size = ULTRA_MAX_DATA - LMP_PID_HEADER;
			self->max_header_size = IRDA_MAX_HEADER + LMP_PID_HEADER;
			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:
			return -ESOCKTNOSUPPORT;
		}
		break;
	default:
		return -ESOCKTNOSUPPORT;
	}

	/* Register as a client with IrLMP */
	self->ckey = irlmp_register_client(0, NULL, NULL, NULL);
	self->mask.word = 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 */
	return 0;
}

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

	/* 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 */
}

/*
 * Function irda_release (sock)
 */
static int irda_release(struct socket *sock)
{
	struct sock *sk = sock->sk;

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

	if (sk == NULL)
		return 0;

	lock_sock(sk);
	sk->sk_state       = TCP_CLOSE;
	sk->sk_shutdown   |= SEND_SHUTDOWN;
	sk->sk_state_change(sk);

	/* Destroy IrDA socket */
	irda_destroy_socket(irda_sk(sk));

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

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

	/* Destroy networking socket if we are the last reference on it,
	 * i.e. if(sk->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 incoming 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 (iocb, sock, msg, len)
 *
 *    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 kiocb *iocb, struct socket *sock,
			struct msghdr *msg, size_t len)
{
	struct sock *sk = sock->sk;
	struct irda_sock *self;
	struct sk_buff *skb;
	int err = -EPIPE;

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

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

	if (sk->sk_shutdown & SEND_SHUTDOWN)
		goto out_err;

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

	self = irda_sk(sk);

	/* Check if IrTTP is wants us to slow down */

	if (wait_event_interruptible(*(sk->sk_sleep),
	    (self->tx_flow != FLOW_STOP  ||  sk->sk_state != TCP_ESTABLISHED)))
		return -ERESTARTSYS;

	/* Check if we are still connected */
	if (sk->sk_state != TCP_ESTABLISHED)
		return -ENOTCONN;

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

	skb = sock_alloc_send_skb(sk, len + self->max_header_size + 16,
				  msg->msg_flags & MSG_DONTWAIT, &err);
	if (!skb)
		goto out_err;

	skb_reserve(skb, self->max_header_size + 16);
	skb_reset_transport_header(skb);
	skb_put(skb, len);
	err = memcpy_fromiovec(skb_transport_header(skb), msg->msg_iov, len);
	if (err) {
		kfree_skb(skb);
		goto out_err;
	}

	/*
	 * 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, "%s(), err=%d\n", __FUNCTION__, err);
		goto out_err;
	}
	/* Tell client how much data we actually sent */
	return len;

 out_err:
	return sk_stream_error(sk, msg->msg_flags, err);

}

/*
 * Function irda_recvmsg_dgram (iocb, sock, msg, size, flags)
 *
 *    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 kiocb *iocb, struct socket *sock,
			      struct msghdr *msg, size_t size, int flags)
{
	struct sock *sk = sock->sk;
	struct irda_sock *self = irda_sk(sk);
	struct sk_buff *skb;
	size_t copied;
	int err;

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

	if ((err = sock_error(sk)) < 0)
		return err;

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

	skb_reset_transport_header(skb);
	copied = skb->len;

	if (copied > size) {
		IRDA_DEBUG(2, "%s(), Received truncated frame (%zd < %zd)!\n",
			   __FUNCTION__, 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->sk_rmem_alloc) << 2) <= sk->sk_rcvbuf) {
			IRDA_DEBUG(2, "%s(), Starting IrTTP\n", __FUNCTION__);
			self->rx_flow = FLOW_START;
			irttp_flow_request(self->tsap, FLOW_START);
		}
	}

	return copied;
}

/*
 * Function irda_recvmsg_stream (iocb, sock, msg, size, flags)
 */
static int irda_recvmsg_stream(struct kiocb *iocb, struct socket *sock,
			       struct msghdr *msg, size_t size, int flags)
{
	struct sock *sk = sock->sk;
	struct irda_sock *self = irda_sk(sk);
	int noblock = flags & MSG_DONTWAIT;
	size_t copied = 0;
	int target, err;
	long timeo;

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

	if ((err = sock_error(sk)) < 0)
		return err;

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

	if (flags & MSG_OOB)
		return -EOPNOTSUPP;

	target = sock_rcvlowat(sk, flags & MSG_WAITALL, size);
	timeo = sock_rcvtimeo(sk, noblock);

	msg->msg_namelen = 0;

	do {
		int chunk;
		struct sk_buff *skb = skb_dequeue(&sk->sk_receive_queue);

		if (skb == NULL) {
			DEFINE_WAIT(wait);
			int ret = 0;

			if (copied >= target)
				break;

			prepare_to_wait_exclusive(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);

			/*
			 *	POSIX 1003.1g mandates this order.
			 */
			ret = sock_error(sk);
			if (ret)
				;
			else if (sk->sk_shutdown & RCV_SHUTDOWN)
				;
			else if (noblock)
				ret = -EAGAIN;
			else if (signal_pending(current))
				ret = sock_intr_errno(timeo);
			else if (sk->sk_state != TCP_ESTABLISHED)
				ret = -ENOTCONN;
			else if (skb_peek(&sk->sk_receive_queue) == NULL)
				/* Wait process until data arrives */
				schedule();

			finish_wait(sk->sk_sleep, &wait);

			if (ret)
				return ret;
			if (sk->sk_shutdown & RCV_SHUTDOWN)
				break;

			continue;
		}

		chunk = min_t(unsigned int, skb->len, size);
		if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
			skb_queue_head(&sk->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, "%s(), back on q!\n",
					   __FUNCTION__);
				skb_queue_head(&sk->sk_receive_queue, skb);
				break;
			}

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

			/* put message back and return */
			skb_queue_head(&sk->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->sk_rmem_alloc) << 2) <= sk->sk_rcvbuf) {
			IRDA_DEBUG(2, "%s(), Starting IrTTP\n", __FUNCTION__);
			self->rx_flow = FLOW_START;
			irttp_flow_request(self->tsap, FLOW_START);
		}
	}

	return copied;