1 files changed, 442 insertions, 0 deletions

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c
new file mode 100644
index 000000000000..df21e900f874
--- /dev/null
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c
@@ -0,0 +1,442 @@
+/* Copyright (c) 2013-2017, The Linux Foundation. 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 version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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.
+ *
+ * RMNET configuration engine
+ *
+ */
+
+#include <net/sock.h>
+#include <linux/module.h>
+#include <linux/netlink.h>
+#include <linux/netdevice.h>
+#include "rmnet_config.h"
+#include "rmnet_handlers.h"
+#include "rmnet_vnd.h"
+#include "rmnet_private.h"
+
+/* Locking scheme -
+ * The shared resource which needs to be protected is realdev->rx_handler_data.
+ * For the writer path, this is using rtnl_lock(). The writer paths are
+ * rmnet_newlink(), rmnet_dellink() and rmnet_force_unassociate_device(). These
+ * paths are already called with rtnl_lock() acquired in. There is also an
+ * ASSERT_RTNL() to ensure that we are calling with rtnl acquired. For
+ * dereference here, we will need to use rtnl_dereference(). Dev list writing
+ * needs to happen with rtnl_lock() acquired for netdev_master_upper_dev_link().
+ * For the reader path, the real_dev->rx_handler_data is called in the TX / RX
+ * path. We only need rcu_read_lock() for these scenarios. In these cases,
+ * the rcu_read_lock() is held in __dev_queue_xmit() and
+ * netif_receive_skb_internal(), so readers need to use rcu_dereference_rtnl()
+ * to get the relevant information. For dev list reading, we again acquire
+ * rcu_read_lock() in rmnet_dellink() for netdev_master_upper_dev_get_rcu().
+ * We also use unregister_netdevice_many() to free all rmnet devices in
+ * rmnet_force_unassociate_device() so we dont lose the rtnl_lock() and free in
+ * same context.
+ */
+
+/* Local Definitions and Declarations */
+
+struct rmnet_walk_data {
+	struct net_device *real_dev;
+	struct list_head *head;
+	struct rmnet_port *port;
+};
+
+static int rmnet_is_real_dev_registered(const struct net_device *real_dev)
+{
+	return rcu_access_pointer(real_dev->rx_handler) == rmnet_rx_handler;
+}
+
+/* Needs rtnl lock */
+static struct rmnet_port*
+rmnet_get_port_rtnl(const struct net_device *real_dev)
+{
+	return rtnl_dereference(real_dev->rx_handler_data);
+}
+
+static int rmnet_unregister_real_device(struct net_device *real_dev,
+					struct rmnet_port *port)
+{
+	if (port->nr_rmnet_devs)
+		return -EINVAL;
+
+	kfree(port);
+
+	netdev_rx_handler_unregister(real_dev);
+
+	/* release reference on real_dev */
+	dev_put(real_dev);
+
+	netdev_dbg(real_dev, "Removed from rmnet\n");
+	return 0;
+}
+
+static int rmnet_register_real_device(struct net_device *real_dev)
+{
+	struct rmnet_port *port;
+	int rc, entry;
+
+	ASSERT_RTNL();
+
+	if (rmnet_is_real_dev_registered(real_dev))
+		return 0;
+
+	port = kzalloc(sizeof(*port), GFP_ATOMIC);
+	if (!port)
+		return -ENOMEM;
+
+	port->dev = real_dev;
+	rc = netdev_rx_handler_register(real_dev, rmnet_rx_handler, port);
+	if (rc) {
+		kfree(port);
+		return -EBUSY;
+	}
+
+	/* hold on to real dev for MAP data */
+	dev_hold(real_dev);
+
+	for (entry = 0; entry < RMNET_MAX_LOGICAL_EP; entry++)
+		INIT_HLIST_HEAD(&port->muxed_ep[entry]);
+
+	netdev_dbg(real_dev, "registered with rmnet\n");
+	return 0;
+}
+
+static void rmnet_unregister_bridge(struct net_device *dev,
+				    struct rmnet_port *port)
+{
+	struct net_device *rmnet_dev, *bridge_dev;
+	struct rmnet_port *bridge_port;
+
+	if (port->rmnet_mode != RMNET_EPMODE_BRIDGE)
+		return;
+
+	/* bridge slave handling */
+	if (!port->nr_rmnet_devs) {
+		rmnet_dev = netdev_master_upper_dev_get_rcu(dev);
+		netdev_upper_dev_unlink(dev, rmnet_dev);
+
+		bridge_dev = port->bridge_ep;
+
+		bridge_port = rmnet_get_port_rtnl(bridge_dev);
+		bridge_port->bridge_ep = NULL;
+		bridge_port->rmnet_mode = RMNET_EPMODE_VND;
+	} else {
+		bridge_dev = port->bridge_ep;
+
+		bridge_port = rmnet_get_port_rtnl(bridge_dev);
+		rmnet_dev = netdev_master_upper_dev_get_rcu(bridge_dev);
+		netdev_upper_dev_unlink(bridge_dev, rmnet_dev);
+
+		rmnet_unregister_real_device(bridge_dev, bridge_port);
+	}
+}
+
+static int rmnet_newlink(struct net *src_net, struct net_device *dev,
+			 struct nlattr *tb[], struct nlattr *data[],
+			 struct netlink_ext_ack *extack)
+{
+	int ingress_format = RMNET_INGRESS_FORMAT_DEMUXING |
+			     RMNET_INGRESS_FORMAT_DEAGGREGATION |
+			     RMNET_INGRESS_FORMAT_MAP;
+	int egress_format = RMNET_EGRESS_FORMAT_MUXING |
+			    RMNET_EGRESS_FORMAT_MAP;
+	struct net_device *real_dev;
+	int mode = RMNET_EPMODE_VND;
+	struct rmnet_endpoint *ep;
+	struct rmnet_port *port;
+	int err = 0;
+	u16 mux_id;
+
+	real_dev = __dev_get_by_index(src_net, nla_get_u32(tb[IFLA_LINK]));
+	if (!real_dev || !dev)
+		return -ENODEV;
+
+	if (!data[IFLA_VLAN_ID])
+		return -EINVAL;
+
+	ep = kzalloc(sizeof(*ep), GFP_ATOMIC);
+	if (!ep)
+		return -ENOMEM;
+
+	mux_id = nla_get_u16(data[IFLA_VLAN_ID]);
+
+	err = rmnet_register_real_device(real_dev);
+	if (err)
+		goto err0;
+
+	port = rmnet_get_port_rtnl(real_dev);
+	err = rmnet_vnd_newlink(mux_id, dev, port, real_dev, ep);
+	if (err)
+		goto err1;
+
+	err = netdev_master_upper_dev_link(dev, real_dev, NULL, NULL, extack);
+	if (err)
+		goto err2;
+
+	netdev_dbg(dev, "data format [ingress 0x%08X] [egress 0x%08X]\n",
+		   ingress_format, egress_format);
+	port->egress_data_format = egress_format;
+	port->ingress_data_format = ingress_format;
+	port->rmnet_mode = mode;
+
+	hlist_add_head_rcu(&ep->hlnode, &port->muxed_ep[mux_id]);
+	return 0;
+
+err2:
+	rmnet_vnd_dellink(mux_id, port, ep);
+err1:
+	rmnet_unregister_real_device(real_dev, port);
+err0:
+	kfree(ep);
+	return err;
+}
+
+static void rmnet_dellink(struct net_device *dev, struct list_head *head)
+{
+	struct net_device *real_dev;
+	struct rmnet_endpoint *ep;
+	struct rmnet_port *port;
+	u8 mux_id;
+
+	rcu_read_lock();
+	real_dev = netdev_master_upper_dev_get_rcu(dev);
+	rcu_read_unlock();
+
+	if (!real_dev || !rmnet_is_real_dev_registered(real_dev))
+		return;
+
+	port = rmnet_get_port_rtnl(real_dev);
+
+	mux_id = rmnet_vnd_get_mux(dev);
+	netdev_upper_dev_unlink(dev, real_dev);
+
+	ep = rmnet_get_endpoint(port, mux_id);
+	if (ep) {
+		hlist_del_init_rcu(&ep->hlnode);
+		rmnet_unregister_bridge(dev, port);
+		rmnet_vnd_dellink(mux_id, port, ep);
+		kfree(ep);
+	}
+	rmnet_unregister_real_device(real_dev, port);
+
+	unregister_netdevice_queue(dev, head);
+}
+
+static int rmnet_dev_walk_unreg(struct net_device *rmnet_dev, void *data)
+{
+	struct rmnet_walk_data *d = data;
+	struct rmnet_endpoint *ep;
+	u8 mux_id;
+
+	mux_id = rmnet_vnd_get_mux(rmnet_dev);
+	ep = rmnet_get_endpoint(d->port, mux_id);
+	if (ep) {
+		hlist_del_init_rcu(&ep->hlnode);
+		rmnet_vnd_dellink(mux_id, d->port, ep);
+		kfree(ep);
+	}
+	netdev_upper_dev_unlink(rmnet_dev, d->real_dev);
+	unregister_netdevice_queue(rmnet_dev, d->head);
+
+	return 0;
+}
+
+static void rmnet_force_unassociate_device(struct net_device *dev)
+{
+	struct net_device *real_dev = dev;
+	struct rmnet_walk_data d;
+	struct rmnet_port *port;
+	LIST_HEAD(list);
+
+	if (!rmnet_is_real_dev_registered(real_dev))
+		return;
+
+	ASSERT_RTNL();
+
+	d.real_dev = real_dev;
+	d.head = &list;
+
+	port = rmnet_get_port_rtnl(dev);
+	d.port = port;
+
+	rcu_read_lock();
+	rmnet_unregister_bridge(dev, port);
+
+	netdev_walk_all_lower_dev_rcu(real_dev, rmnet_dev_walk_unreg, &d);
+	rcu_read_unlock();
+	unregister_netdevice_many(&list);
+
+	rmnet_unregister_real_device(real_dev, port);
+}
+
+static int rmnet_config_notify_cb(struct notifier_block *nb,
+				  unsigned long event, void *data)
+{
+	struct net_device *dev = netdev_notifier_info_to_dev(data);
+
+	if (!dev)
+		return NOTIFY_DONE;
+
+	switch (event) {
+	case NETDEV_UNREGISTER:
+		netdev_dbg(dev, "Kernel unregister\n");
+		rmnet_force_unassociate_device(dev);
+		break;
+
+	default:
+		break;
+	}
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block rmnet_dev_notifier __read_mostly = {
+	.notifier_call = rmnet_config_notify_cb,
+};
+
+static int rmnet_rtnl_validate(struct nlattr *tb[], struct nlattr *data[],
+			       struct netlink_ext_ack *extack)
+{
+	u16 mux_id;
+
+	if (!data || !data[IFLA_VLAN_ID])
+		return -EINVAL;
+
+	mux_id = nla_get_u16(data[IFLA_VLAN_ID]);
+	if (mux_id > (RMNET_MAX_LOGICAL_EP - 1))
+		return -ERANGE;
+
+	return 0;
+}
+
+static size_t rmnet_get_size(const struct net_device *dev)
+{
+	return nla_total_size(2); /* IFLA_VLAN_ID */
+}
+
+struct rtnl_link_ops rmnet_link_ops __read_mostly = {
+	.kind		= "rmnet",
+	.maxtype	= __IFLA_VLAN_MAX,
+	.priv_size	= sizeof(struct rmnet_priv),
+	.setup		= rmnet_vnd_setup,
+	.validate	= rmnet_rtnl_validate,
+	.newlink	= rmnet_newlink,
+	.dellink	= rmnet_dellink,
+	.get_size	= rmnet_get_size,
+};
+
+/* Needs either rcu_read_lock() or rtnl lock */
+struct rmnet_port *rmnet_get_port(struct net_device *real_dev)
+{
+	if (rmnet_is_real_dev_registered(real_dev))
+		return rcu_dereference_rtnl(real_dev->rx_handler_data);
+	else
+		return NULL;
+}
+
+struct rmnet_endpoint *rmnet_get_endpoint(struct rmnet_port *port, u8 mux_id)
+{
+	struct rmnet_endpoint *ep;
+
+	hlist_for_each_entry_rcu(ep, &port->muxed_ep[mux_id], hlnode) {
+		if (ep->mux_id == mux_id)
+			return ep;
+	}
+
+	return NULL;
+}
+
+int rmnet_add_bridge(struct net_device *rmnet_dev,
+		     struct net_device *slave_dev,
+		     struct netlink_ext_ack *extack)
+{
+	struct rmnet_priv *priv = netdev_priv(rmnet_dev);
+	struct net_device *real_dev = priv->real_dev;
+	struct rmnet_port *port, *slave_port;
+	int err;
+
+	port = rmnet_get_port(real_dev);
+
+	/* If there is more than one rmnet dev attached, its probably being
+	 * used for muxing. Skip the briding in that case
+	 */
+	if (port->nr_rmnet_devs > 1)
+		return -EINVAL;
+
+	if (rmnet_is_real_dev_registered(slave_dev))
+		return -EBUSY;
+
+	err = rmnet_register_real_device(slave_dev);
+	if (err)
+		return -EBUSY;
+
+	err = netdev_master_upper_dev_link(slave_dev, rmnet_dev, NULL, NULL,
+					   extack);
+	if (err)
+		return -EINVAL;
+
+	slave_port = rmnet_get_port(slave_dev);
+	slave_port->rmnet_mode = RMNET_EPMODE_BRIDGE;
+	slave_port->bridge_ep = real_dev;
+
+	port->rmnet_mode = RMNET_EPMODE_BRIDGE;
+	port->bridge_ep = slave_dev;
+
+	netdev_dbg(slave_dev, "registered with rmnet as slave\n");
+	return 0;
+}
+
+int rmnet_del_bridge(struct net_device *rmnet_dev,
+		     struct net_device *slave_dev)
+{
+	struct rmnet_priv *priv = netdev_priv(rmnet_dev);
+	struct net_device *real_dev = priv->real_dev;
+	struct rmnet_port *port, *slave_port;
+
+	port = rmnet_get_port(real_dev);
+	port->rmnet_mode = RMNET_EPMODE_VND;
+	port->bridge_ep = NULL;
+
+	netdev_upper_dev_unlink(slave_dev, rmnet_dev);
+	slave_port = rmnet_get_port(slave_dev);
+	rmnet_unregister_real_device(slave_dev, slave_port);
+
+	netdev_dbg(slave_dev, "removed from rmnet as slave\n");
+	return 0;
+}
+
+/* Startup/Shutdown */
+
+static int __init rmnet_init(void)
+{
+	int rc;
+
+	rc = register_netdevice_notifier(&rmnet_dev_notifier);
+	if (rc != 0)
+		return rc;
+
+	rc = rtnl_link_register(&rmnet_link_ops);
+	if (rc != 0) {
+		unregister_netdevice_notifier(&rmnet_dev_notifier);
+		return rc;
+	}
+	return rc;
+}
+
+static void __exit rmnet_exit(void)
+{
+	unregister_netdevice_notifier(&rmnet_dev_notifier);
+	rtnl_link_unregister(&rmnet_link_ops);
+}
+
+module_init(rmnet_init)
+module_exit(rmnet_exit)
+MODULE_LICENSE("GPL v2");