connection.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 777 行 · 第 1/2 页

	/* sanity check */
	if (atomic_read(&conn->usage) <= 0)
		BUG();

	if (likely(!atomic_dec_and_test(&conn->usage))) {
		spin_unlock(&peer->conn_gylock);
		_leave("");
		return;
	}

	/* move to graveyard queue */
	_debug("burying connection: {%08x}", ntohl(conn->conn_id));
	list_del(&conn->link);
	list_add_tail(&conn->link, &peer->conn_graveyard);

	rxrpc_krxtimod_add_timer(&conn->timeout, rxrpc_conn_timeout * HZ);

	spin_unlock(&peer->conn_gylock);

	rxrpc_put_peer(conn->peer);

	_leave(" [killed]");
} /* end rxrpc_put_connection() */

/*****************************************************************************/
/*
 * free a connection record
 */
void rxrpc_conn_do_timeout(struct rxrpc_connection *conn)
{
	struct rxrpc_peer *peer;

	_enter("%p{u=%d p=%hu}",
	       conn, atomic_read(&conn->usage), ntohs(conn->addr.sin_port));

	peer = conn->peer;

	if (atomic_read(&conn->usage) < 0)
		BUG();

	/* remove from graveyard if still dead */
	spin_lock(&peer->conn_gylock);
	if (atomic_read(&conn->usage) == 0) {
		list_del_init(&conn->link);
	}
	else {
		conn = NULL;
	}
	spin_unlock(&peer->conn_gylock);

	if (!conn) {
		_leave("");
		return; /* resurrected */
	}

	_debug("--- Destroying Connection %p{%08x} ---",
	       conn, ntohl(conn->conn_id));

	down_write(&rxrpc_conns_sem);
	list_del(&conn->proc_link);
	up_write(&rxrpc_conns_sem);

	write_lock(&peer->conn_idlock);
	list_del(&conn->id_link);
	write_unlock(&peer->conn_idlock);

	__RXACCT(atomic_dec(&rxrpc_connection_count));
	kfree(conn);

	/* if the graveyard is now empty, wake up anyone waiting for that */
	if (atomic_dec_and_test(&peer->conn_count))
		wake_up(&peer->conn_gy_waitq);

	_leave(" [destroyed]");
} /* end rxrpc_conn_do_timeout() */

/*****************************************************************************/
/*
 * clear all connection records from a peer endpoint
 */
void rxrpc_conn_clearall(struct rxrpc_peer *peer)
{
	DECLARE_WAITQUEUE(myself, current);

	struct rxrpc_connection *conn;
	int err;

	_enter("%p", peer);

	/* there shouldn't be any active conns remaining */
	if (!list_empty(&peer->conn_active))
		BUG();

	/* manually timeout all conns in the graveyard */
	spin_lock(&peer->conn_gylock);
	while (!list_empty(&peer->conn_graveyard)) {
		conn = list_entry(peer->conn_graveyard.next,
				  struct rxrpc_connection, link);
		err = rxrpc_krxtimod_del_timer(&conn->timeout);
		spin_unlock(&peer->conn_gylock);

		if (err == 0)
			rxrpc_conn_do_timeout(conn);

		spin_lock(&peer->conn_gylock);
	}
	spin_unlock(&peer->conn_gylock);

	/* wait for the the conn graveyard to be completely cleared */
	set_current_state(TASK_UNINTERRUPTIBLE);
	add_wait_queue(&peer->conn_gy_waitq, &myself);

	while (atomic_read(&peer->conn_count) != 0) {
		schedule();
		set_current_state(TASK_UNINTERRUPTIBLE);
	}

	remove_wait_queue(&peer->conn_gy_waitq, &myself);
	set_current_state(TASK_RUNNING);

	_leave("");
} /* end rxrpc_conn_clearall() */

/*****************************************************************************/
/*
 * allocate and prepare a message for sending out through the transport
 * endpoint
 */
int rxrpc_conn_newmsg(struct rxrpc_connection *conn,
		      struct rxrpc_call *call,
		      uint8_t type,
		      int dcount,
		      struct kvec diov[],
		      int alloc_flags,
		      struct rxrpc_message **_msg)
{
	struct rxrpc_message *msg;
	int loop;

	_enter("%p{%d},%p,%u", conn, ntohs(conn->addr.sin_port), call, type);

	if (dcount > 3) {
		_leave(" = -EINVAL");
		return -EINVAL;
	}

	msg = kmalloc(sizeof(struct rxrpc_message), alloc_flags);
	if (!msg) {
		_leave(" = -ENOMEM");
		return -ENOMEM;
	}

	memset(msg, 0, sizeof(*msg));
	atomic_set(&msg->usage, 1);

	INIT_LIST_HEAD(&msg->link);

	msg->state = RXRPC_MSG_PREPARED;

	msg->hdr.epoch		= conn->out_epoch;
	msg->hdr.cid		= conn->conn_id | (call ? call->chan_ix : 0);
	msg->hdr.callNumber	= call ? call->call_id : 0;
	msg->hdr.type		= type;
	msg->hdr.flags		= conn->out_clientflag;
	msg->hdr.securityIndex	= conn->security_ix;
	msg->hdr.serviceId	= conn->service_id;

	/* generate sequence numbers for data packets */
	if (call) {
		switch (type) {
		case RXRPC_PACKET_TYPE_DATA:
			msg->seq = ++call->snd_seq_count;
			msg->hdr.seq = htonl(msg->seq);
			break;
		case RXRPC_PACKET_TYPE_ACK:
			/* ACK sequence numbers are complicated. The following
			 * may be wrong:
			 * - jumbo packet ACKs should have a seq number
			 * - normal ACKs should not
			 */
		default:
			break;
		}
	}

	msg->dcount = dcount + 1;
	msg->dsize = sizeof(msg->hdr);
	msg->data[0].iov_len = sizeof(msg->hdr);
	msg->data[0].iov_base = &msg->hdr;

	for (loop=0; loop < dcount; loop++) {
		msg->dsize += diov[loop].iov_len;
		msg->data[loop+1].iov_len  = diov[loop].iov_len;
		msg->data[loop+1].iov_base = diov[loop].iov_base;
	}

	__RXACCT(atomic_inc(&rxrpc_message_count));
	*_msg = msg;
	_leave(" = 0 (%p) #%d", msg, atomic_read(&rxrpc_message_count));
	return 0;
} /* end rxrpc_conn_newmsg() */

/*****************************************************************************/
/*
 * free a message
 */
void __rxrpc_put_message(struct rxrpc_message *msg)
{
	int loop;

	_enter("%p #%d", msg, atomic_read(&rxrpc_message_count));

	if (msg->pkt)
		kfree_skb(msg->pkt);
	rxrpc_put_connection(msg->conn);

	for (loop = 0; loop < 8; loop++)
		if (test_bit(loop, &msg->dfree))
			kfree(msg->data[loop].iov_base);

	__RXACCT(atomic_dec(&rxrpc_message_count));
	kfree(msg);

	_leave("");
} /* end __rxrpc_put_message() */

/*****************************************************************************/
/*
 * send a message out through the transport endpoint
 */
int rxrpc_conn_sendmsg(struct rxrpc_connection *conn,
		       struct rxrpc_message *msg)
{
	struct msghdr msghdr;
	int ret;

	_enter("%p{%d}", conn, ntohs(conn->addr.sin_port));

	/* fill in some fields in the header */
	spin_lock(&conn->lock);
	msg->hdr.serial = htonl(++conn->serial_counter);
	msg->rttdone = 0;
	spin_unlock(&conn->lock);

	/* set up the message to be transmitted */
	msghdr.msg_name		= &conn->addr;
	msghdr.msg_namelen	= sizeof(conn->addr);
	msghdr.msg_control	= NULL;
	msghdr.msg_controllen	= 0;
	msghdr.msg_flags	= MSG_CONFIRM | MSG_DONTWAIT;

	_net("Sending message type %d of %Zd bytes to %08x:%d",
	     msg->hdr.type,
	     msg->dsize,
	     ntohl(conn->addr.sin_addr.s_addr),
	     ntohs(conn->addr.sin_port));

	/* send the message */
	ret = kernel_sendmsg(conn->trans->socket, &msghdr,
			     msg->data, msg->dcount, msg->dsize);
	if (ret < 0) {
		msg->state = RXRPC_MSG_ERROR;
	} else {
		msg->state = RXRPC_MSG_SENT;
		ret = 0;

		spin_lock(&conn->lock);
		do_gettimeofday(&conn->atime);
		msg->stamp = conn->atime;
		spin_unlock(&conn->lock);
	}

	_leave(" = %d", ret);

	return ret;
} /* end rxrpc_conn_sendmsg() */

/*****************************************************************************/
/*
 * deal with a subsequent call packet
 */
int rxrpc_conn_receive_call_packet(struct rxrpc_connection *conn,
				   struct rxrpc_call *call,
				   struct rxrpc_message *msg)
{
	struct rxrpc_message *pmsg;
	struct list_head *_p;
	unsigned cix, seq;
	int ret = 0;

	_enter("%p,%p,%p", conn, call, msg);

	if (!call) {
		cix = ntohl(msg->hdr.cid) & RXRPC_CHANNELMASK;

		spin_lock(&conn->lock);
		call = conn->channels[cix];

		if (!call || call->call_id != msg->hdr.callNumber) {
			spin_unlock(&conn->lock);
			rxrpc_trans_immediate_abort(conn->trans, msg, -ENOENT);
			goto out;
		}
		else {
			rxrpc_get_call(call);
			spin_unlock(&conn->lock);
		}
	}
	else {
		rxrpc_get_call(call);
	}

	_proto("Received packet %%%u [%u] on call %hu:%u:%u",
	       ntohl(msg->hdr.serial),
	       ntohl(msg->hdr.seq),
	       ntohs(msg->hdr.serviceId),
	       ntohl(conn->conn_id),
	       ntohl(call->call_id));

	call->pkt_rcv_count++;

	if (msg->pkt->dst && msg->pkt->dst->dev)
		conn->peer->if_mtu =
			msg->pkt->dst->dev->mtu -
			msg->pkt->dst->dev->hard_header_len;

	/* queue on the call in seq order */
	rxrpc_get_message(msg);
	seq = msg->seq;

	spin_lock(&call->lock);
	list_for_each(_p, &call->rcv_receiveq) {
		pmsg = list_entry(_p, struct rxrpc_message, link);
		if (pmsg->seq > seq)
			break;
	}
	list_add_tail(&msg->link, _p);

	/* reset the activity timeout */
	call->flags |= RXRPC_CALL_RCV_PKT;
	mod_timer(&call->rcv_timeout,jiffies + rxrpc_call_rcv_timeout * HZ);

	spin_unlock(&call->lock);

	rxrpc_krxiod_queue_call(call);

	rxrpc_put_call(call);
 out:
	_leave(" = %d", ret);
	return ret;
} /* end rxrpc_conn_receive_call_packet() */

/*****************************************************************************/
/*
 * handle an ICMP error being applied to a connection
 */
void rxrpc_conn_handle_error(struct rxrpc_connection *conn,
			     int local, int errno)
{
	struct rxrpc_call *calls[4];
	int loop;

	_enter("%p{%d},%d", conn, ntohs(conn->addr.sin_port), errno);

	/* get a ref to all my calls in one go */
	memset(calls, 0, sizeof(calls));
	spin_lock(&conn->lock);

	for (loop = 3; loop >= 0; loop--) {
		if (conn->channels[loop]) {
			calls[loop] = conn->channels[loop];
			rxrpc_get_call(calls[loop]);
		}
	}

	spin_unlock(&conn->lock);

	/* now kick them all */
	for (loop = 3; loop >= 0; loop--) {
		if (calls[loop]) {
			rxrpc_call_handle_error(calls[loop], local, errno);
			rxrpc_put_call(calls[loop]);
		}
	}

	_leave("");
} /* end rxrpc_conn_handle_error() */