/* Copyright (c) 2013-2017, 2019 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 Data configuration engine
 */

#include <net/sock.h>
#include <linux/module.h>
#include <linux/netlink.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <linux/rmnet_data.h>
#include <net/rmnet_config.h>
#include "rmnet_data_config.h"
#include "rmnet_data_handlers.h"
#include "rmnet_data_vnd.h"
#include "rmnet_data_private.h"
#include "rmnet_data_trace.h"
#include "rmnet_map.h"

RMNET_LOG_MODULE(RMNET_DATA_LOGMASK_CONFIG);

/* Local Definitions and Declarations */
static struct sock *nl_socket_handle;

#ifndef RMNET_KERNEL_PRE_3_8
static struct netlink_kernel_cfg rmnet_netlink_cfg = {
	.input = rmnet_config_netlink_msg_handler
};
#endif

static struct notifier_block rmnet_dev_notifier = {
	.notifier_call = rmnet_config_notify_cb,
	.next = 0,
	.priority = 0
};

struct rmnet_free_vnd_work {
	struct work_struct work;
	int vnd_id[RMNET_DATA_MAX_VND];
	int count;
};

/* Init and Cleanup */

#ifdef RMNET_KERNEL_PRE_3_8
static struct sock *_rmnet_config_start_netlink(void)
{
	return netlink_kernel_create(&init_net,
				     RMNET_NETLINK_PROTO,
				     0,
				     rmnet_config_netlink_msg_handler,
				     NULL,
				     THIS_MODULE);
}
#else
static struct sock *_rmnet_config_start_netlink(void)
{
	return netlink_kernel_create(&init_net,
				     RMNET_NETLINK_PROTO,
				     &rmnet_netlink_cfg);
}
#endif /* RMNET_KERNEL_PRE_3_8 */

/* rmnet_config_init() - Startup init
 *
 * Registers netlink protocol with kernel and opens socket. Netlink handler is
 * registered with kernel.
 */
int rmnet_config_init(void)
{
	int rc;

	nl_socket_handle = _rmnet_config_start_netlink();
	if (!nl_socket_handle) {
		LOGE("%s", "Failed to init netlink socket");
		return RMNET_INIT_ERROR;
	}

	rc = register_netdevice_notifier(&rmnet_dev_notifier);
	if (rc != 0) {
		LOGE("Failed to register device notifier; rc=%d", rc);
		/* TODO: Cleanup the nl socket */
		return RMNET_INIT_ERROR;
	}

	return 0;
}

/* rmnet_config_exit() - Cleans up all netlink related resources */
void rmnet_config_exit(void)
{
	int rc;

	netlink_kernel_release(nl_socket_handle);
	rc = unregister_netdevice_notifier(&rmnet_dev_notifier);
	if (rc != 0)
		LOGE("Failed to unregister device notifier; rc=%d", rc);
}

/* Helper Functions */

/* _rmnet_is_physical_endpoint_associated() - Determines if device is associated
 * @dev:      Device to get check
 *
 * Compares device rx_handler callback pointer against known function
 *
 * Return:
 *      - 1 if associated
 *      - 0 if NOT associated
 */
static inline int _rmnet_is_physical_endpoint_associated(struct net_device *dev)
{
	rx_handler_func_t *rx_handler;

	rx_handler = rcu_dereference(dev->rx_handler);

	if (rx_handler == rmnet_rx_handler)
		return 1;
	else
		return 0;
}

/* _rmnet_get_phys_ep_config() - Get physical ep config for an associated device
 * @dev:      Device to get endpoint configuration from
 *
 * Return:
 *     - pointer to configuration if successful
 *     - 0 (null) if device is not associated
 */
struct rmnet_phys_ep_config *_rmnet_get_phys_ep_config
						(struct net_device *dev)
{
	struct rmnet_phys_ep_conf_s *_rmnet_phys_ep_config;

	if (_rmnet_is_physical_endpoint_associated(dev)) {
		_rmnet_phys_ep_config = (struct rmnet_phys_ep_conf_s *)
					rcu_dereference(dev->rx_handler_data);
		if (_rmnet_phys_ep_config && _rmnet_phys_ep_config->config)
			return (struct rmnet_phys_ep_config *)
					_rmnet_phys_ep_config->config;
		else
			return 0;
	} else {
		return 0;
	}
}

/* _rmnet_get_logical_ep() - Gets the logical end point configuration
 * structure for a network device
 * @dev:             Device to get endpoint configuration from
 * @config_id:       Logical endpoint id on device
 * Retrieves the logical_endpoint_config structure.
 *
 * Return:
 *      - End point configuration structure
 *      - NULL in case of an error
 */
struct rmnet_logical_ep_conf_s *_rmnet_get_logical_ep(struct net_device *dev,
						      int config_id)
{
	struct rmnet_phys_ep_config *config;
	struct rmnet_logical_ep_conf_s *epconfig_l;

	if (rmnet_vnd_is_vnd(dev)) {
		epconfig_l = rmnet_vnd_get_le_config(dev);
	} else {
		config = _rmnet_get_phys_ep_config(dev);

		if (!config)
			return NULL;

		if (config_id == RMNET_LOCAL_LOGICAL_ENDPOINT)
			epconfig_l = &config->local_ep;
		else
			epconfig_l = &config->muxed_ep[config_id];
	}

	return epconfig_l;
}

/* Netlink Handler */
static void _rmnet_netlink_set_link_egress_data_format
					(struct rmnet_nl_msg_s *rmnet_header,
					 struct rmnet_nl_msg_s *resp_rmnet)
{
	struct net_device *dev;

	if (!rmnet_header || !resp_rmnet)
		return;

	resp_rmnet->crd = RMNET_NETLINK_MSG_RETURNCODE;
	dev = dev_get_by_name(&init_net, rmnet_header->data_format.dev);

	if (!dev) {
		resp_rmnet->return_code = RMNET_CONFIG_NO_SUCH_DEVICE;
		return;
	}

	resp_rmnet->return_code =
		rmnet_set_egress_data_format(dev,
					     rmnet_header->data_format.flags,
					     rmnet_header->data_format.agg_size,
					     rmnet_header->data_format.agg_count
					     );
	dev_put(dev);
}

static void _rmnet_netlink_set_link_ingress_data_format
					(struct rmnet_nl_msg_s *rmnet_header,
					 struct rmnet_nl_msg_s *resp_rmnet)
{
	struct net_device *dev;

	if (!rmnet_header || !resp_rmnet)
		return;

	resp_rmnet->crd = RMNET_NETLINK_MSG_RETURNCODE;

	dev = dev_get_by_name(&init_net, rmnet_header->data_format.dev);
	if (!dev) {
		resp_rmnet->return_code = RMNET_CONFIG_NO_SUCH_DEVICE;
		return;
	}

	resp_rmnet->return_code = rmnet_set_ingress_data_format(
					dev,
					rmnet_header->data_format.flags,
					rmnet_header->data_format.tail_spacing);
	dev_put(dev);
}

static void _rmnet_netlink_set_logical_ep_config
					(struct rmnet_nl_msg_s *rmnet_header,
					 struct rmnet_nl_msg_s *resp_rmnet)
{
	struct net_device *dev, *dev2;

	if (!rmnet_header || !resp_rmnet)
		return;

	resp_rmnet->crd = RMNET_NETLINK_MSG_RETURNCODE;
	if (rmnet_header->local_ep_config.ep_id < -1 ||
	    rmnet_header->local_ep_config.ep_id > 254) {
		resp_rmnet->return_code = RMNET_CONFIG_BAD_ARGUMENTS;
		return;
	}

	dev = dev_get_by_name(&init_net,
			      rmnet_header->local_ep_config.dev);

	dev2 = dev_get_by_name(&init_net,
			       rmnet_header->local_ep_config.next_dev);

	if (dev && dev2)
		resp_rmnet->return_code =
			rmnet_set_logical_endpoint_config(
				dev,
				rmnet_header->local_ep_config.ep_id,
				rmnet_header->local_ep_config.operating_mode,
				dev2);
	else
		resp_rmnet->return_code = RMNET_CONFIG_NO_SUCH_DEVICE;

	if (dev)
		dev_put(dev);
	if (dev2)
		dev_put(dev2);
}

static void _rmnet_netlink_unset_logical_ep_config
					(struct rmnet_nl_msg_s *rmnet_header,
					 struct rmnet_nl_msg_s *resp_rmnet)
{
	struct net_device *dev;

	if (!rmnet_header || !resp_rmnet)
		return;

	resp_rmnet->crd = RMNET_NETLINK_MSG_RETURNCODE;
	if (rmnet_header->local_ep_config.ep_id < -1 ||
	    rmnet_header->local_ep_config.ep_id > 254) {
		resp_rmnet->return_code = RMNET_CONFIG_BAD_ARGUMENTS;
		return;
	}

	dev = dev_get_by_name(&init_net,
			      rmnet_header->local_ep_config.dev);

	if (dev) {
		resp_rmnet->return_code =
			rmnet_unset_logical_endpoint_config(
				dev,
				rmnet_header->local_ep_config.ep_id);
		dev_put(dev);
	} else {
		resp_rmnet->return_code = RMNET_CONFIG_NO_SUCH_DEVICE;
	}
}

static void _rmnet_netlink_get_logical_ep_config
					(struct rmnet_nl_msg_s *rmnet_header,
					 struct rmnet_nl_msg_s *resp_rmnet)
{
	struct net_device *dev;

	if (!rmnet_header || !resp_rmnet)
		return;

	resp_rmnet->crd = RMNET_NETLINK_MSG_RETURNCODE;
	if (rmnet_header->local_ep_config.ep_id < -1 ||
	    rmnet_header->local_ep_config.ep_id > 254) {
		resp_rmnet->return_code = RMNET_CONFIG_BAD_ARGUMENTS;
		return;
	}

	dev = dev_get_by_name(&init_net,
			      rmnet_header->local_ep_config.dev);

	if (dev)
		resp_rmnet->return_code =
			rmnet_get_logical_endpoint_config(
				dev,
				rmnet_header->local_ep_config.ep_id,
				&resp_rmnet->local_ep_config.operating_mode,
				resp_rmnet->local_ep_config.next_dev,
				sizeof(resp_rmnet->local_ep_config.next_dev));
	else {
		resp_rmnet->return_code = RMNET_CONFIG_NO_SUCH_DEVICE;
		return;
	}

	if (resp_rmnet->return_code == RMNET_CONFIG_OK) {
		/* Begin Data */
		resp_rmnet->crd = RMNET_NETLINK_MSG_RETURNDATA;
		resp_rmnet->arg_length = sizeof(((struct rmnet_nl_msg_s *)0)
						->local_ep_config);
	}
	dev_put(dev);
}

static void _rmnet_netlink_associate_network_device
					(struct rmnet_nl_msg_s *rmnet_header,
					 struct rmnet_nl_msg_s *resp_rmnet)
{
	struct net_device *dev;

	if (!rmnet_header || !resp_rmnet)
		return;

	resp_rmnet->crd = RMNET_NETLINK_MSG_RETURNCODE;

	dev = dev_get_by_name(&init_net, rmnet_header->data);
	if (!dev) {
		resp_rmnet->return_code = RMNET_CONFIG_NO_SUCH_DEVICE;
		return;
	}

	resp_rmnet->return_code = rmnet_associate_network_device(dev);
	dev_put(dev);
}

static void _rmnet_netlink_unassociate_network_device
					(struct rmnet_nl_msg_s *rmnet_header,
					 struct rmnet_nl_msg_s *resp_rmnet)
{
	struct net_device *dev;

	if (!rmnet_header || !resp_rmnet)
		return;

	resp_rmnet->crd = RMNET_NETLINK_MSG_RETURNCODE;

	dev = dev_get_by_name(&init_net, rmnet_header->data);
	if (!dev) {
		resp_rmnet->return_code = RMNET_CONFIG_NO_SUCH_DEVICE;
		return;
	}

	resp_rmnet->return_code = rmnet_unassociate_network_device(dev);
	dev_put(dev);
}

static void _rmnet_netlink_get_network_device_associated
					(struct rmnet_nl_msg_s *rmnet_header,
					 struct rmnet_nl_msg_s *resp_rmnet)
{
	struct net_device *dev;

	if (!rmnet_header || !resp_rmnet)
		return;

	resp_rmnet->crd = RMNET_NETLINK_MSG_RETURNCODE;

	dev = dev_get_by_name(&init_net, rmnet_header->data);
	if (!dev) {
		resp_rmnet->return_code = RMNET_CONFIG_NO_SUCH_DEVICE;
		return;
	}

	resp_rmnet->return_code = _rmnet_is_physical_endpoint_associated(dev);
	resp_rmnet->crd = RMNET_NETLINK_MSG_RETURNDATA;
	dev_put(dev);
}

static void _rmnet_netlink_get_link_egress_data_format
					(struct rmnet_nl_msg_s *rmnet_header,
					 struct rmnet_nl_msg_s *resp_rmnet)
{
	struct net_device *dev;
	struct rmnet_phys_ep_config *config;

	if (!rmnet_header || !resp_rmnet)
		return;

	resp_rmnet->crd = RMNET_NETLINK_MSG_RETURNCODE;

	dev = dev_get_by_name(&init_net, rmnet_header->data_format.dev);
	if (!dev) {
		resp_rmnet->return_code = RMNET_CONFIG_NO_SUCH_DEVICE;
		return;
	}

	config = _rmnet_get_phys_ep_config(dev);
	if (!config) {
		resp_rmnet->return_code = RMNET_CONFIG_INVALID_REQUEST;
		dev_put(dev);
		return;
	}

	/* Begin Data */
	resp_rmnet->crd = RMNET_NETLINK_MSG_RETURNDATA;
	resp_rmnet->arg_length = sizeof(((struct rmnet_nl_msg_s *)0)
					->data_format);
	resp_rmnet->data_format.flags = config->egress_data_format;
	resp_rmnet->data_format.agg_count = config->egress_agg_count;
	resp_rmnet->data_format.agg_size  = config->egress_agg_size;
	dev_put(dev);
}

static void _rmnet_netlink_get_link_ingress_data_format
					(struct rmnet_nl_msg_s *rmnet_header,
					 struct rmnet_nl_msg_s *resp_rmnet)
{
	struct net_device *dev;
	struct rmnet_phys_ep_config *config;

	if (!rmnet_header || !resp_rmnet)
		return;

	resp_rmnet->crd = RMNET_NETLINK_MSG_RETURNCODE;

	dev = dev_get_by_name(&init_net, rmnet_header->data_format.dev);
	if (!dev) {
		resp_rmnet->return_code = RMNET_CONFIG_NO_SUCH_DEVICE;
		return;
	}

	config = _rmnet_get_phys_ep_config(dev);
	if (!config) {
		resp_rmnet->return_code = RMNET_CONFIG_INVALID_REQUEST;
		dev_put(dev);
		return;
	}

	/* Begin Data */
	resp_rmnet->crd = RMNET_NETLINK_MSG_RETURNDATA;
	resp_rmnet->arg_length = sizeof(((struct rmnet_nl_msg_s *)0)
					->data_format);
	resp_rmnet->data_format.flags = config->ingress_data_format;
	resp_rmnet->data_format.tail_spacing = config->tail_spacing;
	dev_put(dev);
}

static void _rmnet_netlink_get_vnd_name
					(struct rmnet_nl_msg_s *rmnet_header,
					 struct rmnet_nl_msg_s *resp_rmnet)
{
	int r;

	if (!rmnet_header || !resp_rmnet)
		return;

	resp_rmnet->crd = RMNET_NETLINK_MSG_RETURNCODE;

	r = rmnet_vnd_get_name(rmnet_header->vnd.id, resp_rmnet->vnd.vnd_name,
			       RMNET_MAX_STR_LEN);

	if (r != 0) {
		resp_rmnet->return_code = RMNET_CONFIG_INVALID_REQUEST;
		return;
	}

	/* Begin Data */
	resp_rmnet->crd = RMNET_NETLINK_MSG_RETURNDATA;
	resp_rmnet->arg_length = sizeof(((struct rmnet_nl_msg_s *)0)->vnd);
}

static void _rmnet_netlink_add_del_vnd_tc_flow
					(u32 command,
					 struct rmnet_nl_msg_s *rmnet_header,
					 struct rmnet_nl_msg_s *resp_rmnet)
{
	u32 id;
	u32 map_flow_id;
	u32 tc_flow_id;

	if (!rmnet_header || !resp_rmnet)
		return;

	resp_rmnet->crd = RMNET_NETLINK_MSG_RETURNCODE;

	id = rmnet_header->flow_control.id;
	map_flow_id = rmnet_header->flow_control.map_flow_id;
	tc_flow_id = rmnet_header->flow_control.tc_flow_id;

	switch (command) {
	case RMNET_NETLINK_ADD_VND_TC_FLOW:
		resp_rmnet->return_code = rmnet_vnd_add_tc_flow(id,
								map_flow_id,
								tc_flow_id);
		break;
	case RMNET_NETLINK_DEL_VND_TC_FLOW:
		resp_rmnet->return_code = rmnet_vnd_del_tc_flow(id,
								map_flow_id,
								tc_flow_id);
		break;
	default:
		LOGM("Called with unhandled command %d", command);
		resp_rmnet->return_code = RMNET_CONFIG_INVALID_REQUEST;
		break;
	}
}

/* rmnet_config_netlink_msg_handler() - Netlink message handler callback
 * @skb:      Packet containing netlink messages
 *
 * Standard kernel-expected format for a netlink message handler. Processes SKBs
 * which contain RmNet data specific netlink messages.
 */
void rmnet_config_netlink_msg_handler(struct sk_buff *skb)
{
	struct nlmsghdr *nlmsg_header, *resp_nlmsg;
	struct rmnet_nl_msg_s *rmnet_header, *resp_rmnet;
	int return_pid, response_data_length;
	struct sk_buff *skb_response;

	response_data_length = 0;
	nlmsg_header = (struct nlmsghdr *)skb->data;
	rmnet_header = (struct rmnet_nl_msg_s *)nlmsg_data(nlmsg_header);

	if (!nlmsg_header->nlmsg_pid ||
	    (nlmsg_header->nlmsg_len < sizeof(struct nlmsghdr) +
				       sizeof(struct rmnet_nl_msg_s)))
		return;

	LOGL("Netlink message pid=%d, seq=%d, length=%d, rmnet_type=%d",
	     nlmsg_header->nlmsg_pid,
	     nlmsg_header->nlmsg_seq,
	     nlmsg_header->nlmsg_len,
	     rmnet_header->message_type);

	return_pid = nlmsg_header->nlmsg_pid;

	skb_response = nlmsg_new(sizeof(struct nlmsghdr)
				 + sizeof(struct rmnet_nl_msg_s),
				 GFP_KERNEL);

	if (!skb_response) {
		LOGH("%s", "Failed to allocate response buffer");
		return;
	}

	resp_nlmsg = nlmsg_put(skb_response,
			       0,
			       nlmsg_header->nlmsg_seq,
			       NLMSG_DONE,
			       sizeof(struct rmnet_nl_msg_s),
			       0);

	resp_rmnet = nlmsg_data(resp_nlmsg);

	if (!resp_rmnet)
		return;

	resp_rmnet->message_type = rmnet_header->message_type;
	rtnl_lock();
	switch (rmnet_header->message_type) {
	case RMNET_NETLINK_ASSOCIATE_NETWORK_DEVICE:
		_rmnet_netlink_associate_network_device
						(rmnet_header, resp_rmnet);
		break;

	case RMNET_NETLINK_UNASSOCIATE_NETWORK_DEVICE:
		_rmnet_netlink_unassociate_network_device
						(rmnet_header, resp_rmnet);
		break;

	case RMNET_NETLINK_GET_NETWORK_DEVICE_ASSOCIATED:
		_rmnet_netlink_get_network_device_associated
						(rmnet_header, resp_rmnet);
		break;

	case RMNET_NETLINK_SET_LINK_EGRESS_DATA_FORMAT:
		_rmnet_netlink_set_link_egress_data_format
						(rmnet_header, resp_rmnet);
		break;

	case RMNET_NETLINK_GET_LINK_EGRESS_DATA_FORMAT:
		_rmnet_netlink_get_link_egress_data_format
						(rmnet_header, resp_rmnet);
		break;

	case RMNET_NETLINK_SET_LINK_INGRESS_DATA_FORMAT:
		_rmnet_netlink_set_link_ingress_data_format
						(rmnet_header, resp_rmnet);
		break;

	case RMNET_NETLINK_GET_LINK_INGRESS_DATA_FORMAT:
		_rmnet_netlink_get_link_ingress_data_format
						(rmnet_header, resp_rmnet);
		break;

	case RMNET_NETLINK_SET_LOGICAL_EP_CONFIG:
		_rmnet_netlink_set_logical_ep_config(rmnet_header, resp_rmnet);
		break;

	case RMNET_NETLINK_UNSET_LOGICAL_EP_CONFIG:
		_rmnet_netlink_unset_logical_ep_config(rmnet_header,
						       resp_rmnet);
		break;

	case RMNET_NETLINK_GET_LOGICAL_EP_CONFIG:
		_rmnet_netlink_get_logical_ep_config(rmnet_header, resp_rmnet);
		break;

	case RMNET_NETLINK_NEW_VND:
		resp_rmnet->crd = RMNET_NETLINK_MSG_RETURNCODE;
		resp_rmnet->return_code =
					 rmnet_create_vnd(rmnet_header->vnd.id);
		break;

	case RMNET_NETLINK_NEW_VND_WITH_PREFIX:
		resp_rmnet->crd = RMNET_NETLINK_MSG_RETURNCODE;
		resp_rmnet->return_code = rmnet_create_vnd_prefix(
						rmnet_header->vnd.id,
						rmnet_header->vnd.vnd_name);
		break;

	case RMNET_NETLINK_NEW_VND_WITH_NAME:
		resp_rmnet->crd = RMNET_NETLINK_MSG_RETURNCODE;
		resp_rmnet->return_code = rmnet_create_vnd_name(
						rmnet_header->vnd.id,
						rmnet_header->vnd.vnd_name);
		break;

	case RMNET_NETLINK_FREE_VND:
		resp_rmnet->crd = RMNET_NETLINK_MSG_RETURNCODE;
		/* Please check rmnet_vnd_free_dev documentation regarding
		 * the below locking sequence
		 */
		rtnl_unlock();
		resp_rmnet->return_code = rmnet_free_vnd(rmnet_header->vnd.id);
		rtnl_lock();
		break;

	case RMNET_NETLINK_GET_VND_NAME:
		_rmnet_netlink_get_vnd_name(rmnet_header, resp_rmnet);
		break;

	case RMNET_NETLINK_DEL_VND_TC_FLOW:
	case RMNET_NETLINK_ADD_VND_TC_FLOW:
		_rmnet_netlink_add_del_vnd_tc_flow(rmnet_header->message_type,
						   rmnet_header,
						   resp_rmnet);
		break;

	default:
		resp_rmnet->crd = RMNET_NETLINK_MSG_RETURNCODE;
		resp_rmnet->return_code = RMNET_CONFIG_UNKNOWN_MESSAGE;
		break;
	}
	rtnl_unlock();
	nlmsg_unicast(nl_socket_handle, skb_response, return_pid);
	LOGD("%s", "Done processing command");
}

/* Configuration API */

/* rmnet_unassociate_network_device() - Unassociate network device
 * @dev:      Device to unassociate
 *
 * Frees all structures generate for device. Unregisters rx_handler
 * todo: needs to do some sanity verification first (is device in use, etc...)
 *
 * Return:
 *      - RMNET_CONFIG_OK if successful
 *      - RMNET_CONFIG_NO_SUCH_DEVICE dev is null
 *      - RMNET_CONFIG_INVALID_REQUEST if device is not already associated
 *      - RMNET_CONFIG_DEVICE_IN_USE if device has logical ep that wasn't unset
 *      - RMNET_CONFIG_UNKNOWN_ERROR net_device private section is null
 */
int rmnet_unassociate_network_device(struct net_device *dev)
{
	struct rmnet_phys_ep_conf_s *config;
	int config_id = RMNET_LOCAL_LOGICAL_ENDPOINT;
	struct rmnet_logical_ep_conf_s *epconfig_l;

	ASSERT_RTNL();

	LOGL("(%s);", dev->name);

	if (!dev)
		return RMNET_CONFIG_NO_SUCH_DEVICE;

	if (!_rmnet_is_physical_endpoint_associated(dev))
		return RMNET_CONFIG_INVALID_REQUEST;

	for (; config_id < RMNET_DATA_MAX_LOGICAL_EP; config_id++) {
		epconfig_l = _rmnet_get_logical_ep(dev, config_id);
		if (epconfig_l && epconfig_l->refcount)
			return RMNET_CONFIG_DEVICE_IN_USE;
	}

	config = (struct rmnet_phys_ep_conf_s *)
		rcu_dereference(dev->rx_handler_data);

	if (!config)
		return RMNET_CONFIG_UNKNOWN_ERROR;

	kfree(config);

	netdev_rx_handler_unregister(dev);

	/* Explicitly release the reference from the device */
	dev_put(dev);
	trace_rmnet_unassociate(dev);
	return RMNET_CONFIG_OK;
}

/* rmnet_set_ingress_data_format() - Set ingress data format on network device
 * @dev:                 Device to ingress data format on
 * @egress_data_format:  32-bit unsigned bitmask of ingress format
 *
 * Network device must already have association with RmNet Data driver
 *
 * Return:
 *      - RMNET_CONFIG_OK if successful
 *      - RMNET_CONFIG_NO_SUCH_DEVICE dev is null
 *      - RMNET_CONFIG_UNKNOWN_ERROR net_device private section is null
 */
int rmnet_set_ingress_data_format(struct net_device *dev,
				  u32 ingress_data_format,
				  uint8_t  tail_spacing)
{
	struct rmnet_phys_ep_config *config;

	ASSERT_RTNL();

	LOGL("(%s,0x%08X);", dev->name, ingress_data_format);

	if (!dev)
		return RMNET_CONFIG_NO_SUCH_DEVICE;

	config = _rmnet_get_phys_ep_config(dev);

	if (!config)
		return RMNET_CONFIG_INVALID_REQUEST;

	config->ingress_data_format = ingress_data_format;
	config->tail_spacing = tail_spacing;

	return RMNET_CONFIG_OK;
}

/* rmnet_set_egress_data_format() - Set egress data format on network device
 * @dev:                 Device to egress data format on
 * @egress_data_format:  32-bit unsigned bitmask of egress format
 *
 * Network device must already have association with RmNet Data driver
 * todo: Bounds check on agg_*
 *
 * Return:
 *      - RMNET_CONFIG_OK if successful
 *      - RMNET_CONFIG_NO_SUCH_DEVICE dev is null
 *      - RMNET_CONFIG_UNKNOWN_ERROR net_device private section is null
 */
int rmnet_set_egress_data_format(struct net_device *dev,
				 u32 egress_data_format,
				 u16 agg_size,
				 u16 agg_count)
{
	struct rmnet_phys_ep_config *config;
	unsigned long flags;

	ASSERT_RTNL();

	LOGL("(%s,0x%08X, %d, %d);",
	     dev->name, egress_data_format, agg_size, agg_count);

	if (!dev)
		return RMNET_CONFIG_NO_SUCH_DEVICE;

	config = _rmnet_get_phys_ep_config(dev);

	if (!config)
		return RMNET_CONFIG_UNKNOWN_ERROR;

	config->egress_data_format = egress_data_format;

	spin_lock_irqsave(&config->agg_lock, flags);
	config->egress_agg_size = agg_size;
	config->egress_agg_count = agg_count;
	spin_unlock_irqrestore(&config->agg_lock, flags);

	return RMNET_CONFIG_OK;
}

/* rmnet_associate_network_device() - Associate network device
 * @dev:      Device to register with RmNet data
 *
 * Typically used on physical network devices. Registers RX handler and private
 * metadata structures.
 *
 * Return:
 *      - RMNET_CONFIG_OK if successful
 *      - RMNET_CONFIG_NO_SUCH_DEVICE dev is null
 *      - RMNET_CONFIG_INVALID_REQUEST if the device to be associated is a vnd
 *      - RMNET_CONFIG_DEVICE_IN_USE if dev rx_handler is already filled
 *      - RMNET_CONFIG_DEVICE_IN_USE if netdev_rx_handler_register() fails
 */
int rmnet_associate_network_device(struct net_device *dev)
{
	struct rmnet_phys_ep_conf_s *config;
	struct rmnet_phys_ep_config *conf;
	int rc;

	ASSERT_RTNL();

	LOGL("(%s);\n", dev->name);

	if (!dev)
		return RMNET_CONFIG_NO_SUCH_DEVICE;

	if (_rmnet_is_physical_endpoint_associated(dev)) {
		LOGM("%s is already regestered", dev->name);
		return RMNET_CONFIG_DEVICE_IN_USE;
	}

	if (rmnet_vnd_is_vnd(dev)) {
		LOGM("%s is a vnd", dev->name);
		return RMNET_CONFIG_INVALID_REQUEST;
	}

	config = kmalloc(sizeof(*config), GFP_ATOMIC);
	conf = kmalloc(sizeof(*conf), GFP_ATOMIC);

	if (!config || !conf)
		return RMNET_CONFIG_NOMEM;

	memset(config, 0, sizeof(struct rmnet_phys_ep_conf_s));
	memset(conf, 0, sizeof(struct rmnet_phys_ep_config));

	config->config = conf;
	conf->dev = dev;
	spin_lock_init(&conf->agg_lock);
	config->recycle = kfree_skb;
	hrtimer_init(&conf->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
	conf->hrtimer.function = rmnet_map_flush_packet_queue;
	rc = netdev_rx_handler_register(dev, rmnet_rx_handler, config);

	if (rc) {
		LOGM("netdev_rx_handler_register returns %d", rc);
		kfree(config);
		kfree(conf);
		return RMNET_CONFIG_DEVICE_IN_USE;
	}

	/* Explicitly hold a reference to the device */
	dev_hold(dev);
	trace_rmnet_associate(dev);
	return RMNET_CONFIG_OK;
}

/* _rmnet_set_logical_endpoint_config() - Set logical endpoing config on device
 * @dev:         Device to set endpoint configuration on
 * @config_id:   logical endpoint id on device
 * @epconfig:    endpoing configuration structure to set
 *
 * Return:
 *      - RMNET_CONFIG_OK if successful
 *      - RMNET_CONFIG_UNKNOWN_ERROR net_device private section is null
 *      - RMNET_CONFIG_NO_SUCH_DEVICE if device to set config on is null
 *      - RMNET_CONFIG_DEVICE_IN_USE if device already has a logical ep
 *      - RMNET_CONFIG_BAD_ARGUMENTS if logical endpoint id is out of range
 */
int _rmnet_set_logical_endpoint_config(struct net_device *dev,
				       int config_id,
				       struct rmnet_logical_ep_conf_s *epconfig)
{
	struct rmnet_logical_ep_conf_s *epconfig_l;

	ASSERT_RTNL();

	if (!dev)
		return RMNET_CONFIG_NO_SUCH_DEVICE;

	if (config_id < RMNET_LOCAL_LOGICAL_ENDPOINT ||
	    config_id >= RMNET_DATA_MAX_LOGICAL_EP)
		return RMNET_CONFIG_BAD_ARGUMENTS;

	epconfig_l = _rmnet_get_logical_ep(dev, config_id);

	if (!epconfig_l)
		return RMNET_CONFIG_UNKNOWN_ERROR;

	if (epconfig_l->refcount)
		return RMNET_CONFIG_DEVICE_IN_USE;

	memcpy(epconfig_l, epconfig, sizeof(struct rmnet_logical_ep_conf_s));
	if (config_id == RMNET_LOCAL_LOGICAL_ENDPOINT)
		epconfig_l->mux_id = 0;
	else
		epconfig_l->mux_id = config_id;

	/* Explicitly hold a reference to the egress device */
	dev_hold(epconfig_l->egress_dev);
	return RMNET_CONFIG_OK;
}

/* _rmnet_unset_logical_endpoint_config() - Un-set the logical endpoing config
 * on device
 * @dev:         Device to set endpoint configuration on
 * @config_id:   logical endpoint id on device
 *
 * Return:
 *      - RMNET_CONFIG_OK if successful
 *      - RMNET_CONFIG_UNKNOWN_ERROR net_device private section is null
 *      - RMNET_CONFIG_NO_SUCH_DEVICE if device to set config on is null
 *      - RMNET_CONFIG_BAD_ARGUMENTS if logical endpoint id is out of range
 */
int _rmnet_unset_logical_endpoint_config(struct net_device *dev,
					 int config_id)
{
	struct rmnet_logical_ep_conf_s *epconfig_l = 0;

	ASSERT_RTNL();

	if (!dev)
		return RMNET_CONFIG_NO_SUCH_DEVICE;

	if (config_id < RMNET_LOCAL_LOGICAL_ENDPOINT ||
	    config_id >= RMNET_DATA_MAX_LOGICAL_EP)
		return RMNET_CONFIG_BAD_ARGUMENTS;

	epconfig_l = _rmnet_get_logical_ep(dev, config_id);

	if (!epconfig_l || !epconfig_l->refcount)
		return RMNET_CONFIG_NO_SUCH_DEVICE;

	/* Explicitly release the reference from the egress device */
	dev_put(epconfig_l->egress_dev);
	memset(epconfig_l, 0, sizeof(struct rmnet_logical_ep_conf_s));

	return RMNET_CONFIG_OK;
}

/* rmnet_set_logical_endpoint_config() - Set logical endpoint config on a device
 * @dev:            Device to set endpoint configuration on
 * @config_id:      logical endpoint id on device
 * @rmnet_mode:     endpoint mode. Values from: rmnet_config_endpoint_modes_e
 * @egress_device:  device node to forward packet to once done processing in
 *                  ingress/egress handlers
 *
 * Creates a logical_endpoint_config structure and fills in the information from
 * function arguments. Calls _rmnet_set_logical_endpoint_config() to finish
 * configuration. Network device must already have association with RmNet Data
 * driver
 *
 * Return:
 *      - RMNET_CONFIG_OK if successful
 *      - RMNET_CONFIG_BAD_EGRESS_DEVICE if egress device is null
 *      - RMNET_CONFIG_BAD_EGRESS_DEVICE if egress device is not handled by
 *                                       RmNet data module
 *      - RMNET_CONFIG_UNKNOWN_ERROR net_device private section is null
 *      - RMNET_CONFIG_NO_SUCH_DEVICE if device to set config on is null
 *      - RMNET_CONFIG_BAD_ARGUMENTS if logical endpoint id is out of range
 */
int rmnet_set_logical_endpoint_config(struct net_device *dev,
				      int config_id,
				      u8 rmnet_mode,
				      struct net_device *egress_dev)
{
	struct rmnet_logical_ep_conf_s epconfig;

	LOGL("(%s, %d, %d, %s);",
	     dev->name, config_id, rmnet_mode, egress_dev->name);

	if (!egress_dev ||
	    ((!_rmnet_is_physical_endpoint_associated(egress_dev)) &&
	    (!rmnet_vnd_is_vnd(egress_dev)))) {
		return RMNET_CONFIG_BAD_EGRESS_DEVICE;
	}

	memset(&epconfig, 0, sizeof(struct rmnet_logical_ep_conf_s));
	epconfig.refcount = 1;
	epconfig.rmnet_mode = rmnet_mode;
	epconfig.egress_dev = egress_dev;

	return _rmnet_set_logical_endpoint_config(dev, config_id, &epconfig);
}

/* rmnet_unset_logical_endpoint_config() - Un-set logical endpoing configuration
 * on a device
 * @dev:            Device to set endpoint configuration on
 * @config_id:      logical endpoint id on device
 *
 * Retrieves the logical_endpoint_config structure and frees the egress device.
 * Network device must already have association with RmNet Data driver
 *
 * Return:
 *      - RMNET_CONFIG_OK if successful
 *      - RMNET_CONFIG_UNKNOWN_ERROR net_device private section is null
 *      - RMNET_CONFIG_NO_SUCH_DEVICE device is not associated
 *      - RMNET_CONFIG_BAD_ARGUMENTS if logical endpoint id is out of range
 */
int rmnet_unset_logical_endpoint_config(struct net_device *dev,
					int config_id)
{
	LOGL("(%s, %d);", dev->name, config_id);

	if (!dev || ((!_rmnet_is_physical_endpoint_associated(dev)) &&
		     (!rmnet_vnd_is_vnd(dev)))) {
		return RMNET_CONFIG_NO_SUCH_DEVICE;
	}

	return _rmnet_unset_logical_endpoint_config(dev, config_id);
}

/* rmnet_get_logical_endpoint_config() - Gets logical endpoing configuration
 * for a device
 * @dev:                  Device to get endpoint configuration on
 * @config_id:            logical endpoint id on device
 * @rmnet_mode:           (I/O) logical endpoint mode
 * @egress_dev_name:      (I/O) logical endpoint egress device name
 * @egress_dev_name_size: The maximal size of the I/O egress_dev_name
 *
 * Retrieves the logical_endpoint_config structure.
 * Network device must already have association with RmNet Data driver
 *
 * Return:
 *      - RMNET_CONFIG_OK if successful
 *      - RMNET_CONFIG_UNKNOWN_ERROR net_device private section is null
 *      - RMNET_CONFIG_NO_SUCH_DEVICE device is not associated
 *      - RMNET_CONFIG_BAD_ARGUMENTS if logical endpoint id is out of range or
 *        if the provided buffer size for egress dev name is too short
 */
int rmnet_get_logical_endpoint_config(struct net_device *dev,
				      int config_id,
				      u8 *rmnet_mode,
				      u8 *egress_dev_name,
				      size_t egress_dev_name_size)
{
	struct rmnet_logical_ep_conf_s *epconfig_l = 0;
	size_t strlcpy_res = 0;

	LOGL("(%s, %d);", dev->name, config_id);

	if (!egress_dev_name || !rmnet_mode)
		return RMNET_CONFIG_BAD_ARGUMENTS;
	if (config_id < RMNET_LOCAL_LOGICAL_ENDPOINT ||
	    config_id >= RMNET_DATA_MAX_LOGICAL_EP)
		return RMNET_CONFIG_BAD_ARGUMENTS;

	epconfig_l = _rmnet_get_logical_ep(dev, config_id);

	if (!epconfig_l || !epconfig_l->refcount)
		return RMNET_CONFIG_NO_SUCH_DEVICE;

	*rmnet_mode = epconfig_l->rmnet_mode;

	strlcpy_res = strlcpy(egress_dev_name, epconfig_l->egress_dev->name,
			      egress_dev_name_size);

	if (strlcpy_res >= egress_dev_name_size)
		return RMNET_CONFIG_BAD_ARGUMENTS;

	return RMNET_CONFIG_OK;
}

/* rmnet_create_vnd() - Create virtual network device node
 * @id:       RmNet virtual device node id
 *
 * Return:
 *      - result of rmnet_vnd_create_dev()
 */
int rmnet_create_vnd(int id)
{
	struct net_device *dev;

	ASSERT_RTNL();
	LOGL("(%d);", id);
	return rmnet_vnd_create_dev(id, &dev, NULL, 0);
}

/* rmnet_create_vnd_prefix() - Create virtual network device node
 * @id:       RmNet virtual device node id
 * @prefix:   String prefix for device name
 *
 * Return:
 *      - result of rmnet_vnd_create_dev()
 */
int rmnet_create_vnd_prefix(int id, const char *prefix)
{
	struct net_device *dev;

	ASSERT_RTNL();
	LOGL("(%d, \"%s\");", id, prefix);
	return rmnet_vnd_create_dev(id, &dev, prefix, 0);
}

/**
 * rmnet_create_vnd_name() - Create virtual network device node
 * @id:       RmNet virtual device node id
 * @prefix:   String prefix for device name
 *
 * Return:
 *      - result of rmnet_vnd_create_dev()
 */
int rmnet_create_vnd_name(int id, const char *name)
{
	struct net_device *dev;

	ASSERT_RTNL();
	LOGL("(%d, \"%s\");", id, name);
	return rmnet_vnd_create_dev(id, &dev, name, 1);
}

/* rmnet_free_vnd() - Free virtual network device node
 * @id:       RmNet virtual device node id
 *
 * Return:
 *      - result of rmnet_vnd_free_dev()
 */
int rmnet_free_vnd(int id)
{
	LOGL("(%d);", id);
	return rmnet_vnd_free_dev(id);
}

static void _rmnet_free_vnd_later(struct work_struct *work)
{
	int i;
	struct rmnet_free_vnd_work *fwork;

	fwork = container_of(work, struct rmnet_free_vnd_work, work);

	for (i = 0; i < fwork->count; i++)
		rmnet_free_vnd(fwork->vnd_id[i]);
	kfree(fwork);
}

/* rmnet_force_unassociate_device() - Force a device to unassociate
 * @dev:       Device to unassociate
 *
 * Return:
 *      - void
 */
static void rmnet_force_unassociate_device(struct net_device *dev)
{
	int i, j;
	struct net_device *vndev;
	struct rmnet_phys_ep_config *config;
	struct rmnet_logical_ep_conf_s *cfg;
	struct rmnet_free_vnd_work *vnd_work;

	ASSERT_RTNL();

	if (!dev)
		return;

	if (!_rmnet_is_physical_endpoint_associated(dev)) {
		LOGM("%s", "Called on unassociated device, skipping");
		return;
	}

	trace_rmnet_unregister_cb_clear_vnds(dev);
	vnd_work = kmalloc(sizeof(*vnd_work), GFP_KERNEL);
	if (!vnd_work) {
		LOGH("%s", "Out of Memory");
		return;
	}
	INIT_WORK(&vnd_work->work, _rmnet_free_vnd_later);
	vnd_work->count = 0;

	/* Check the VNDs for offending mappings */
	for (i = 0, j = 0; i < RMNET_DATA_MAX_VND &&
	     j < RMNET_DATA_MAX_VND; i++) {
		vndev = rmnet_vnd_get_by_id(i);
		if (!vndev) {
			LOGL("VND %d not in use; skipping", i);
			continue;
		}
		cfg = rmnet_vnd_get_le_config(vndev);
		if (!cfg) {
			LOGH("Got NULL config from VND %d", i);
			continue;
		}
		if (cfg->refcount && (cfg->egress_dev == dev)) {
			/* Make sure the device is down before clearing any of
			 * the mappings. Otherwise we could see a potential
			 * race condition if packets are actively being
			 * transmitted.
			 */
			dev_close(vndev);
			rmnet_unset_logical_endpoint_config
				(vndev, RMNET_LOCAL_LOGICAL_ENDPOINT);
			vnd_work->vnd_id[j] = i;
			j++;
		}
	}
	if (j > 0) {
		vnd_work->count = j;
		schedule_work(&vnd_work->work);
	} else {
		kfree(vnd_work);
	}

	config = _rmnet_get_phys_ep_config(dev);

	if (config) {
		unsigned long flags;

		hrtimer_cancel(&config->hrtimer);
		spin_lock_irqsave(&config->agg_lock, flags);
		if (config->agg_state == RMNET_MAP_TXFER_SCHEDULED) {
			if (config->agg_skb) {
				kfree_skb(config->agg_skb);
				config->agg_skb = NULL;
				config->agg_count = 0;
				memset(&config->agg_time, 0,
				       sizeof(struct timespec));
			}
			config->agg_state = RMNET_MAP_AGG_IDLE;
		}
		spin_unlock_irqrestore(&config->agg_lock, flags);

		cfg = &config->local_ep;

		if (cfg && cfg->refcount)
			rmnet_unset_logical_endpoint_config
			(cfg->egress_dev, RMNET_LOCAL_LOGICAL_ENDPOINT);
	}

	/* Clear the mappings on the phys ep */
	trace_rmnet_unregister_cb_clear_lepcs(dev);
	rmnet_unset_logical_endpoint_config(dev, RMNET_LOCAL_LOGICAL_ENDPOINT);
	for (i = 0; i < RMNET_DATA_MAX_LOGICAL_EP; i++)
		rmnet_unset_logical_endpoint_config(dev, i);
	rmnet_unassociate_network_device(dev);
}

/* rmnet_config_notify_cb() - Callback for netdevice notifier chain
 * @nb:       Notifier block data
 * @event:    Netdevice notifier event ID
 * @data:     Contains a net device for which we are getting notified
 *
 * Return:
 *      - result of NOTIFY_DONE()
 */
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;

	LOGL("(..., %lu, %s)", event, dev->name);

	switch (event) {
	case NETDEV_UNREGISTER_FINAL:
	case NETDEV_UNREGISTER:
		trace_rmnet_unregister_cb_entry(dev);
		LOGH("Kernel is trying to unregister %s", dev->name);
		rmnet_force_unassociate_device(dev);
		trace_rmnet_unregister_cb_exit(dev);
		break;

	default:
		trace_rmnet_unregister_cb_unhandled(dev);
		LOGD("Unhandeled event [%lu]", event);
		break;
	}

	return NOTIFY_DONE;
}