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/*
 * Copyright (c) 2016 Intel Corporation.
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <logging/log.h>
LOG_MODULE_REGISTER(net_mgmt, CONFIG_NET_MGMT_EVENT_LOG_LEVEL);

#include <kernel.h>
#include <toolchain.h>
#include <linker/sections.h>

#include <sys/util.h>
#include <sys/slist.h>
#include <net/net_mgmt.h>

#include "net_private.h"

struct mgmt_event_entry {
	u32_t event;
	struct net_if *iface;

#ifdef CONFIG_NET_MGMT_EVENT_INFO
	u8_t info[NET_EVENT_INFO_MAX_SIZE];
	size_t info_length;
#endif /* CONFIG_NET_MGMT_EVENT_INFO */
};

struct mgmt_event_wait {
	struct k_sem sync_call;
	struct net_if *iface;
};

static K_SEM_DEFINE(network_event, 0, UINT_MAX);
static K_SEM_DEFINE(net_mgmt_lock, 1, 1);

NET_STACK_DEFINE(MGMT, mgmt_stack, CONFIG_NET_MGMT_EVENT_STACK_SIZE,
		 CONFIG_NET_MGMT_EVENT_STACK_SIZE);
static struct k_thread mgmt_thread_data;
static struct mgmt_event_entry events[CONFIG_NET_MGMT_EVENT_QUEUE_SIZE];
static u32_t global_event_mask;
static sys_slist_t event_callbacks;
static s16_t in_event;
static s16_t out_event;

static inline void mgmt_push_event(u32_t mgmt_event, struct net_if *iface,
				   void *info, size_t length)
{
	s16_t i_idx;

#ifndef CONFIG_NET_MGMT_EVENT_INFO
	ARG_UNUSED(info);
	ARG_UNUSED(length);
#endif /* CONFIG_NET_MGMT_EVENT_INFO */

	k_sem_take(&net_mgmt_lock, K_FOREVER);

	i_idx = in_event + 1;
	if (i_idx == CONFIG_NET_MGMT_EVENT_QUEUE_SIZE) {
		i_idx = 0;
	}

#ifdef CONFIG_NET_MGMT_EVENT_INFO
	if (info && length) {
		if (length <= NET_EVENT_INFO_MAX_SIZE) {
			memcpy(events[i_idx].info, info, length);
			events[i_idx].info_length = length;
		} else {
			NET_ERR("Event info length %zu > max size %zu",
				length, NET_EVENT_INFO_MAX_SIZE);
			k_sem_give(&net_mgmt_lock);

			return;
		}
	} else {
		events[i_idx].info_length = 0;
	}
#endif /* CONFIG_NET_MGMT_EVENT_INFO */

	events[i_idx].event = mgmt_event;
	events[i_idx].iface = iface;

	if (i_idx == out_event) {
		u16_t o_idx = out_event + 1;

		if (o_idx == CONFIG_NET_MGMT_EVENT_QUEUE_SIZE) {
			o_idx = 0U;
		}

		if (events[o_idx].event) {
			out_event = o_idx;
		}
	} else if (out_event < 0) {
		out_event = i_idx;
	}

	in_event = i_idx;

	k_sem_give(&net_mgmt_lock);
}

static inline struct mgmt_event_entry *mgmt_pop_event(void)
{
	s16_t o_idx;

	if (out_event < 0 || !events[out_event].event) {
		return NULL;
	}

	o_idx = out_event;
	out_event++;

	if (o_idx == in_event) {
		in_event = -1;
		out_event = -1;
	} else if (out_event == CONFIG_NET_MGMT_EVENT_QUEUE_SIZE) {
		out_event = 0;
	}

	return &events[o_idx];
}

static inline void mgmt_clean_event(struct mgmt_event_entry *mgmt_event)
{
	mgmt_event->event = 0U;
	mgmt_event->iface = NULL;
}

static inline void mgmt_add_event_mask(u32_t event_mask)
{
	global_event_mask |= event_mask;
}

static inline void mgmt_rebuild_global_event_mask(void)
{
	struct net_mgmt_event_callback *cb, *tmp;

	global_event_mask = 0U;

	SYS_SLIST_FOR_EACH_CONTAINER_SAFE(&event_callbacks, cb, tmp, node) {
		mgmt_add_event_mask(cb->event_mask);
	}
}

static inline bool mgmt_is_event_handled(u32_t mgmt_event)
{
	return (((NET_MGMT_GET_LAYER(mgmt_event) &
		  NET_MGMT_GET_LAYER(global_event_mask)) ==
		 NET_MGMT_GET_LAYER(mgmt_event)) &&
		((NET_MGMT_GET_LAYER_CODE(mgmt_event) &
		  NET_MGMT_GET_LAYER_CODE(global_event_mask)) ==
		 NET_MGMT_GET_LAYER_CODE(mgmt_event)) &&
		((NET_MGMT_GET_COMMAND(mgmt_event) &
		  NET_MGMT_GET_COMMAND(global_event_mask)) ==
		 NET_MGMT_GET_COMMAND(mgmt_event)));
}

static inline void mgmt_run_callbacks(struct mgmt_event_entry *mgmt_event)
{
	sys_snode_t *prev = NULL;
	struct net_mgmt_event_callback *cb, *tmp;

	NET_DBG("Event layer %u code %u cmd %u",
		NET_MGMT_GET_LAYER(mgmt_event->event),
		NET_MGMT_GET_LAYER_CODE(mgmt_event->event),
		NET_MGMT_GET_COMMAND(mgmt_event->event));

	SYS_SLIST_FOR_EACH_CONTAINER_SAFE(&event_callbacks, cb, tmp, node) {
		if (!(NET_MGMT_GET_LAYER(mgmt_event->event) ==
		      NET_MGMT_GET_LAYER(cb->event_mask)) ||
		    !(NET_MGMT_GET_LAYER_CODE(mgmt_event->event) ==
		      NET_MGMT_GET_LAYER_CODE(cb->event_mask)) ||
		    (NET_MGMT_GET_COMMAND(mgmt_event->event) &&
		     NET_MGMT_GET_COMMAND(cb->event_mask) &&
		     !(NET_MGMT_GET_COMMAND(mgmt_event->event) &
		       NET_MGMT_GET_COMMAND(cb->event_mask)))) {
			continue;
		}

#ifdef CONFIG_NET_MGMT_EVENT_INFO
		if (mgmt_event->info_length) {
			cb->info = (void *)mgmt_event->info;
			cb->info_length = mgmt_event->info_length;
		} else {
			cb->info = NULL;
			cb->info_length = 0;
		}
#endif /* CONFIG_NET_MGMT_EVENT_INFO */

		if (NET_MGMT_EVENT_SYNCHRONOUS(cb->event_mask)) {
			struct mgmt_event_wait *sync_data =
				CONTAINER_OF(cb->sync_call,
					     struct mgmt_event_wait, sync_call);

			if (sync_data->iface &&
			    sync_data->iface != mgmt_event->iface) {
				continue;
			}

			NET_DBG("Unlocking %p synchronous call", cb);

			cb->raised_event = mgmt_event->event;
			sync_data->iface = mgmt_event->iface;

			sys_slist_remove(&event_callbacks, prev, &cb->node);

			k_sem_give(cb->sync_call);
		} else {
			NET_DBG("Running callback %p : %p",
				cb, cb->handler);

			cb->handler(cb, mgmt_event->event, mgmt_event->iface);
			prev = &cb->node;
		}
	}

#ifdef CONFIG_NET_DEBUG_MGMT_EVENT_STACK
	net_analyze_stack("Net MGMT event stack",
			  Z_THREAD_STACK_BUFFER(mgmt_stack),
			  K_THREAD_STACK_SIZEOF(mgmt_stack));
#endif
}

static void mgmt_thread(void)
{
	struct mgmt_event_entry *mgmt_event;

	while (1) {
		k_sem_take(&network_event, K_FOREVER);
		k_sem_take(&net_mgmt_lock, K_FOREVER);

		NET_DBG("Handling events, forwarding it relevantly");

		mgmt_event = mgmt_pop_event();
		if (!mgmt_event) {
			/* System is over-loaded?
			 * At this point we have most probably notified
			 * more events than we could handle
			 */
			NET_DBG("Some event got probably lost (%u)",
				k_sem_count_get(&network_event));

			k_sem_init(&network_event, 0, UINT_MAX);
			k_sem_give(&net_mgmt_lock);

			continue;
		}

		mgmt_run_callbacks(mgmt_event);

		mgmt_clean_event(mgmt_event);

		k_sem_give(&net_mgmt_lock);

		k_yield();
	}
}

static int mgmt_event_wait_call(struct net_if *iface,
				u32_t mgmt_event_mask,
				u32_t *raised_event,
				struct net_if **event_iface,
				const void **info,
				size_t *info_length,
				int timeout)
{
	struct mgmt_event_wait sync_data = {
		.sync_call = Z_SEM_INITIALIZER(sync_data.sync_call, 0, 1),
	};
	struct net_mgmt_event_callback sync = {
		.sync_call = &sync_data.sync_call,
		.event_mask = mgmt_event_mask | NET_MGMT_SYNC_EVENT_BIT,
	};
	int ret;

	if (iface) {
		sync_data.iface = iface;
	}

	NET_DBG("Synchronous event 0x%08x wait %p", sync.event_mask, &sync);

	net_mgmt_add_event_callback(&sync);

	ret = k_sem_take(sync.sync_call, timeout);
	if (ret == -EAGAIN) {
		ret = -ETIMEDOUT;
	} else {
		if (!ret) {
			if (raised_event) {
				*raised_event = sync.raised_event;
			}

			if (event_iface) {
				*event_iface = sync_data.iface;
			}

#ifdef CONFIG_NET_MGMT_EVENT_INFO
			if (info) {
				*info = sync.info;

				if (info_length) {
					*info_length = sync.info_length;
				}
			}
#endif /* CONFIG_NET_MGMT_EVENT_INFO */
		}
	}

	return ret;
}

void net_mgmt_add_event_callback(struct net_mgmt_event_callback *cb)
{
	NET_DBG("Adding event callback %p", cb);

	k_sem_take(&net_mgmt_lock, K_FOREVER);

	sys_slist_prepend(&event_callbacks, &cb->node);

	mgmt_add_event_mask(cb->event_mask);

	k_sem_give(&net_mgmt_lock);
}

void net_mgmt_del_event_callback(struct net_mgmt_event_callback *cb)
{
	NET_DBG("Deleting event callback %p", cb);

	k_sem_take(&net_mgmt_lock, K_FOREVER);

	sys_slist_find_and_remove(&event_callbacks, &cb->node);

	mgmt_rebuild_global_event_mask();

	k_sem_give(&net_mgmt_lock);
}

void net_mgmt_event_notify_with_info(u32_t mgmt_event, struct net_if *iface,
				     void *info, size_t length)
{
	if (mgmt_is_event_handled(mgmt_event)) {
		NET_DBG("Notifying Event layer %u code %u type %u",
			NET_MGMT_GET_LAYER(mgmt_event),
			NET_MGMT_GET_LAYER_CODE(mgmt_event),
			NET_MGMT_GET_COMMAND(mgmt_event));

		mgmt_push_event(mgmt_event, iface, info, length);
		k_sem_give(&network_event);
	}
}

int net_mgmt_event_wait(u32_t mgmt_event_mask,
			u32_t *raised_event,
			struct net_if **iface,
			const void **info,
			size_t *info_length,
			int timeout)
{
	return mgmt_event_wait_call(NULL, mgmt_event_mask,
				    raised_event, iface, info, info_length,
				    timeout);
}

int net_mgmt_event_wait_on_iface(struct net_if *iface,
				 u32_t mgmt_event_mask,
				 u32_t *raised_event,
				 const void **info,
				 size_t *info_length,
				 int timeout)
{
	NET_ASSERT(NET_MGMT_ON_IFACE(mgmt_event_mask));
	NET_ASSERT(iface);

	return mgmt_event_wait_call(iface, mgmt_event_mask,
				    raised_event, NULL, info, info_length,
				    timeout);
}

void net_mgmt_event_init(void)
{
	sys_slist_init(&event_callbacks);
	global_event_mask = 0U;

	in_event = -1;
	out_event = -1;

	(void)memset(events, 0, CONFIG_NET_MGMT_EVENT_QUEUE_SIZE *
			sizeof(struct mgmt_event_entry));

	k_thread_create(&mgmt_thread_data, mgmt_stack,
			K_THREAD_STACK_SIZEOF(mgmt_stack),
			(k_thread_entry_t)mgmt_thread, NULL, NULL, NULL,
			K_PRIO_COOP(CONFIG_NET_MGMT_EVENT_THREAD_PRIO), 0, 0);
	k_thread_name_set(&mgmt_thread_data, "net_mgmt");

	NET_DBG("Net MGMT initialized: queue of %u entries, stack size of %u",
		CONFIG_NET_MGMT_EVENT_QUEUE_SIZE,
		CONFIG_NET_MGMT_EVENT_STACK_SIZE);
}