/*
 *
 *  Wireless daemon for Linux
 *
 *  Copyright (C) 2013-2014  Intel Corporation. All rights reserved.
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library 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
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdlib.h>
#include <sys/socket.h>
#include <linux/if.h>
#include <linux/if_ether.h>
#include <ell/ell.h>

#include "linux/nl80211.h"
#include "src/wiphy.h"

static struct l_genl *genl = NULL;
static struct l_genl_family *nl80211 = NULL;

struct netdev {
	uint32_t index;
	char name[IFNAMSIZ];
	uint32_t type;
	uint8_t addr[ETH_ALEN];
};

struct wiphy {
	uint32_t id;
	char name[20];
	struct l_queue *netdev_list;
};

static struct l_queue *wiphy_list = NULL;

static void do_debug(const char *str, void *user_data)
{
	const char *prefix = user_data;

	l_info("%s%s", prefix, str);
}

static void netdev_free(void *data)
{
	struct netdev *netdev = data;

	l_debug("Freeing interface %s", netdev->name);

	l_free(netdev);
}

static bool netdev_match(const void *a, const void *b)
{
	const struct netdev *netdev = a;
	uint32_t index = L_PTR_TO_UINT(b);

	return (netdev->index == index);
}

static void wiphy_free(void *data)
{
	struct wiphy *wiphy = data;

	l_debug("Freeing wiphy %s", wiphy->name);

	l_queue_destroy(wiphy->netdev_list, netdev_free);

	l_free(wiphy);
}

static bool wiphy_match(const void *a, const void *b)
{
	const struct wiphy *wiphy = a;
	uint32_t id = L_PTR_TO_UINT(b);

	return (wiphy->id == id);
}

static void wiphy_interface_dump_callback(struct l_genl_msg *msg,
							void *user_data)
{
	struct wiphy *wiphy = user_data;
	struct netdev *netdev;
	struct l_genl_attr attr;
	uint16_t type, len;
	const void *data;
	char ifname[IFNAMSIZ];
	uint8_t ifaddr[ETH_ALEN];
	uint32_t ifindex, iftype;

	if (!l_genl_attr_init(&attr, msg))
		return;

	memset(ifname, 0, sizeof(ifname));
	memset(ifaddr, 0, sizeof(ifaddr));
	iftype = NL80211_IFTYPE_UNSPECIFIED;
	ifindex = 0;

	/*
	 * The interface index and interface name attributes are normally
	 * listed before the wiphy attribute. This handling assumes that
	 * all attributes are included in the same message.
	 *
	 * If any required attribute is missing, the whole message will
	 * be ignored.
	 */
	while (l_genl_attr_next(&attr, &type, &len, &data)) {
		switch (type) {
		case NL80211_ATTR_IFINDEX:
			if (len != sizeof(uint32_t)) {
				l_warn("Invalid interface index attribute");
				return;
			}

			ifindex = *((uint32_t *) data);
			break;

		case NL80211_ATTR_IFNAME:
			if (len > sizeof(ifname)) {
				l_warn("Invalid interface name attribute");
				return;
			}

			memcpy(ifname, data, len);
			break;

		case NL80211_ATTR_WIPHY:
			if (len != sizeof(uint32_t)) {
				l_warn("Invalid wiphy attribute");
				return;
			}

			if (wiphy->id != *((uint32_t *) data)) {
				l_warn("Mismatching wiphy attribute");
				return;
			}
			break;

		case NL80211_ATTR_IFTYPE:
			if (len != sizeof(uint32_t)) {
				l_warn("Invalid interface type attribute");
				return;
			}

			iftype = *((uint32_t *) data);
			break;

		case NL80211_ATTR_MAC:
			if (len != sizeof(ifaddr)) {
				l_warn("Invalid interface address attribute");
				return;
			}

			memcpy(ifaddr, data, len);
			break;
		}
	}

	if (!ifindex) {
		l_warn("Missing interface index attribute");
		return;
	}

	netdev = l_queue_find(wiphy->netdev_list, netdev_match,
						L_UINT_TO_PTR(ifindex));
	if (!netdev) {
		netdev = l_new(struct netdev, 1);
		l_queue_push_tail(wiphy->netdev_list, netdev);
	}

	memcpy(netdev->name, ifname, sizeof(netdev->name));
	memcpy(netdev->addr, ifaddr, sizeof(netdev->addr));
	netdev->index = ifindex;
	netdev->type = iftype;

	l_debug("Found interface %s", netdev->name);
}

static void wiphy_get_interfaces(struct wiphy *wiphy)
{
	struct l_genl_msg *msg;

	msg = l_genl_msg_new_sized(NL80211_CMD_GET_INTERFACE, 8);

	if (!l_genl_msg_append_attr(msg, NL80211_ATTR_WIPHY,
					sizeof(uint32_t), &wiphy->id))
		return;

	l_genl_family_dump(nl80211, msg, wiphy_interface_dump_callback,
								wiphy, NULL);
}

static void wiphy_dump_callback(struct l_genl_msg *msg, void *user_data)
{
	struct wiphy *wiphy = NULL;
	struct l_genl_attr attr;
	uint16_t type, len;
	const void *data;
	uint32_t id;
	bool created = false;

	if (!l_genl_attr_init(&attr, msg))
		return;

	/*
	 * The wiphy attribute is always the first attribute in the
	 * list. If not then error out with a warning and ignore the
	 * whole message.
	 *
	 * In most cases multiple of these message will be send
	 * since the information included can not fit into a single
	 * message.
	 */
	while (l_genl_attr_next(&attr, &type, &len, &data)) {
		switch (type) {
		case NL80211_ATTR_WIPHY:
			if (wiphy) {
				l_warn("Duplicate wiphy attribute");
				return;
			}

			if (len != sizeof(uint32_t)) {
				l_warn("Invalid wiphy attribute");
				return;
			}

			id = *((uint32_t *) data);

			wiphy = l_queue_find(wiphy_list, wiphy_match,
							L_UINT_TO_PTR(id));
			if (!wiphy) {
				wiphy = l_new(struct wiphy, 1);
				wiphy->id = id;
				wiphy->netdev_list = l_queue_new();
				l_queue_push_tail(wiphy_list, wiphy);
				created = true;
			}
			break;

		case NL80211_ATTR_WIPHY_NAME:
			if (!wiphy) {
				l_warn("No wiphy structure found");
				return;
			}

			if (len > sizeof(wiphy->name)) {
				l_warn("Invalid wiphy name attribute");
				return;
			}

			memcpy(wiphy->name, data, len);
			break;
		}
	}

	if (created) {
		l_debug("Found wiphy %s", wiphy->name);
		wiphy_get_interfaces(wiphy);
	}
}

static void nl80211_appeared(void *user_data)
{
	struct l_genl_msg *msg;

	l_debug("Found nl80211 interface");

	/*
	 * This is an extra sanity check so that no memory is leaked
	 * in case the generic netlink handling gets confused.
	 */
	if (wiphy_list) {
		l_warn("Destroying existing list of wiphy devices");
		l_queue_destroy(wiphy_list, NULL);
	}

	wiphy_list = l_queue_new();

	msg = l_genl_msg_new(NL80211_CMD_GET_WIPHY);

	l_genl_family_dump(nl80211, msg, wiphy_dump_callback, NULL, NULL);
}

static void nl80211_vanished(void *user_data)
{
	l_debug("Lost nl80211 interface");

	l_queue_destroy(wiphy_list, wiphy_free);
	wiphy_list = NULL;
}

bool wiphy_init(void)
{
	if (genl)
		return false;

	genl = l_genl_new_default();
	if (!genl) {
		l_error("Failed to open generic netlink socket");
		return false;
	}

	if (getenv("IWD_GENL_DEBUG"))
		l_genl_set_debug(genl, do_debug, "[GENL] ", NULL);

	l_debug("Opening nl80211 interface");

	nl80211 = l_genl_family_new(genl, NL80211_GENL_NAME);
	if (!nl80211) {
		l_error("Failed to open nl80211 interface");
		goto failed;
	}

	l_genl_family_set_watches(nl80211, nl80211_appeared, nl80211_vanished,
								NULL, NULL);

	return true;

failed:
	l_genl_unref(genl);
	genl = NULL;

	return false;
}

bool wiphy_exit(void)
{
	if (!genl)
		return false;

	l_debug("Closing nl80211 interface");

	/*
	 * The generic netlink master object keeps track of all families
	 * and closing it will take care of freeing all associated resources.
	 */
	l_genl_unref(genl);
	genl = NULL;

	/*
	 * This is an extra sanity check so that no memory is leaked
	 * in case the generic netlink handling forgets to call the
	 * vanished callback.
	 */
	if (wiphy_list) {
		l_warn("Found leftover list of wiphy devices");
		l_queue_destroy(wiphy_list, wiphy_free);
		wiphy_list = NULL;
	}

	return true;
}