/*
 *
 *  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 <linux/rtnetlink.h>
#include <net/if_arp.h>
#include <linux/if.h>
#include <linux/if_ether.h>
#include <errno.h>

#include <ell/ell.h>

#include "linux/nl80211.h"

#include "src/iwd.h"
#include "src/wiphy.h"
#include "src/ie.h"
#include "src/mpdu.h"
#include "src/eapol.h"
#include "src/crypto.h"
#include "src/device.h"
#include "src/scan.h"
#include "src/netdev.h"

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

	netdev_event_func_t event_filter;
	netdev_connect_cb_t connect_cb;
	void *user_data;
	struct l_genl_msg *associate_msg;
	struct eapol_sm *sm;
	uint8_t remote_addr[ETH_ALEN];
};

static struct l_netlink *rtnl = NULL;
static struct l_genl_family *nl80211;
static struct l_queue *netdev_list;

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

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

struct cb_data {
	netdev_command_func_t callback;
	void *user_data;
};

static void netlink_result(int error, uint16_t type, const void *data,
			uint32_t len, void *user_data)
{
	struct cb_data *cb_data = user_data;

	if (!cb_data)
		return;

	cb_data->callback(error < 0 ? false : true, cb_data->user_data);

	l_free(cb_data);
}

static size_t rta_add_u8(void *rta_buf, unsigned short type, uint8_t value)
{
	struct rtattr *rta = rta_buf;

	rta->rta_len = RTA_LENGTH(sizeof(uint8_t));
	rta->rta_type = type;
	*((uint8_t *) RTA_DATA(rta)) = value;

	return RTA_SPACE(sizeof(uint8_t));
}

void netdev_set_linkmode_and_operstate(uint32_t ifindex,
				uint8_t linkmode, uint8_t operstate,
				netdev_command_func_t callback, void *user_data)
{
	struct ifinfomsg *rtmmsg;
	void *rta_buf;
	size_t bufsize;
	struct cb_data *cb_data = NULL;

	bufsize = NLMSG_LENGTH(sizeof(struct ifinfomsg)) +
		RTA_SPACE(sizeof(uint8_t)) + RTA_SPACE(sizeof(uint8_t));

	rtmmsg = l_malloc(bufsize);
	memset(rtmmsg, 0, bufsize);

	rtmmsg->ifi_family = AF_UNSPEC;
	rtmmsg->ifi_index = ifindex;

	rta_buf = rtmmsg + 1;

	rta_buf += rta_add_u8(rta_buf, IFLA_LINKMODE, linkmode);
	rta_buf += rta_add_u8(rta_buf, IFLA_OPERSTATE, operstate);

	if (callback) {
		cb_data = l_new(struct cb_data, 1);
		cb_data->callback = callback;
		cb_data->user_data = user_data;
	}

	l_netlink_send(rtnl, RTM_SETLINK, 0, rtmmsg,
					rta_buf - (void *) rtmmsg,
					netlink_result, cb_data, NULL);

	l_free(rtmmsg);
}

const uint8_t *netdev_get_address(struct netdev *netdev)
{
	return netdev->addr;
}

uint32_t netdev_get_ifindex(struct netdev *netdev)
{
	return netdev->index;
}

uint32_t netdev_get_iftype(struct netdev *netdev)
{
	return netdev->type;
}

const char *netdev_get_name(struct netdev *netdev)
{
	return netdev->name;
}

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

	l_debug("Freeing netdev %s[%d]", netdev->name, netdev->index);

	if (netdev->sm) {
		eapol_sm_free(netdev->sm);
		netdev->sm = NULL;
	}

	if (netdev->associate_msg) {
		l_genl_msg_unref(netdev->associate_msg);
		netdev->associate_msg = NULL;
	}

	l_free(netdev);
}

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

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

struct netdev *netdev_find(int ifindex)
{
	return l_queue_find(netdev_list, netdev_match, L_UINT_TO_PTR(ifindex));
}

static void netdev_lost_beacon(struct netdev *netdev)
{
	if (!netdev->event_filter)
		return;

	netdev->event_filter(netdev, NETDEV_EVENT_LOST_BEACON,
							netdev->user_data);
}

static void netdev_cqm_event(struct l_genl_msg *msg, struct netdev *netdev)
{
	struct l_genl_attr attr;
	struct l_genl_attr nested;
	uint16_t type, len;
	const void *data;

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

	while (l_genl_attr_next(&attr, &type, &len, &data)) {
		switch (type) {
		case NL80211_ATTR_CQM:
			if (!l_genl_attr_recurse(&attr, &nested))
				return;

			while (l_genl_attr_next(&nested, &type, &len, &data)) {
				switch (type) {
				case NL80211_ATTR_CQM_BEACON_LOSS_EVENT:
					netdev_lost_beacon(netdev);
					break;
				}
			}

			break;
		}
	}
}

static void netdev_disconnect_event(struct l_genl_msg *msg,
							struct netdev *netdev)
{
	struct l_genl_attr attr;
	uint16_t type, len;
	const void *data;
	uint16_t reason_code = 0;
	bool disconnect_by_ap = false;

	l_debug("");

	if (!l_genl_attr_init(&attr, msg)) {
		l_error("attr init failed");
		return;
	}

	while (l_genl_attr_next(&attr, &type, &len, &data)) {
		switch (type) {
		case NL80211_ATTR_REASON_CODE:
			if (len != sizeof(uint16_t))
				l_warn("Invalid reason code attribute");
			else
				reason_code = *((uint16_t *) data);

			break;

		case NL80211_ATTR_DISCONNECTED_BY_AP:
			disconnect_by_ap = true;
			break;
		}
	}

	l_info("Received Deauthentication event, reason: %hu, from_ap: %s",
			reason_code, disconnect_by_ap ? "true" : "false");

	if (!disconnect_by_ap)
		return;

	if (netdev->event_filter)
		netdev->event_filter(netdev, NETDEV_EVENT_DISCONNECT_BY_AP,
							netdev->user_data);
}

static void netdev_deauthenticate_event(struct l_genl_msg *msg,
							struct netdev *netdev)
{
	l_debug("");
}

static struct l_genl_msg *netdev_build_cmd_deauthenticate(struct netdev *netdev,
							uint16_t reason_code)
{
	struct l_genl_msg *msg;

	msg = l_genl_msg_new_sized(NL80211_CMD_DEAUTHENTICATE, 128);
	l_genl_msg_append_attr(msg, NL80211_ATTR_IFINDEX, 4, &netdev->index);
	l_genl_msg_append_attr(msg, NL80211_ATTR_REASON_CODE, 2, &reason_code);
	l_genl_msg_append_attr(msg, NL80211_ATTR_MAC, ETH_ALEN,
							netdev->remote_addr);

	return msg;
}

static void netdev_operstate_cb(bool success, void *user_data)
{
	struct netdev *netdev = user_data;
	enum netdev_result result;

	if (!success) {
		struct l_genl_msg *msg;

		l_error("Setting LinkMode and OperState failed for ifindex: %d",
				netdev->index);

		msg = netdev_build_cmd_deauthenticate(netdev,
						MPDU_REASON_CODE_UNSPECIFIED);
		l_genl_family_send(nl80211, msg, NULL, NULL, NULL);

		result = NETDEV_RESULT_KEY_SETTING_FAILED;
	} else
		result = NETDEV_RESULT_OK;

	if (netdev->connect_cb)
		netdev->connect_cb(netdev, result, netdev->user_data);
}

static void netdev_handshake_failed(uint32_t ifindex,
					const uint8_t *aa, const uint8_t *spa,
					uint16_t reason_code, void *user_data)
{
	struct l_genl_msg *msg;
	struct netdev *netdev;

	netdev = netdev_find(ifindex);
	if (!netdev)
		return;

	l_error("4-Way Handshake failed for ifindex: %d", ifindex);

	msg = netdev_build_cmd_deauthenticate(netdev, reason_code);
	l_genl_family_send(nl80211, msg, NULL, NULL, NULL);

	if (netdev->connect_cb)
		netdev->connect_cb(netdev, NETDEV_RESULT_HANDSHAKE_FAILED,
						netdev->user_data);
}

static void netdev_associate_event(struct l_genl_msg *msg,
							struct netdev *netdev)
{
	int err;

	l_debug("");

	err = l_genl_msg_get_error(msg);
	if (err < 0) {
		l_error("association failed %s (%d)", strerror(-err), err);
		goto error;
	}

	if (netdev->sm) {
		eapol_start(netdev->index, netdev->sm);
		netdev->sm = NULL;

		if (netdev->event_filter)
			netdev->event_filter(netdev,
					NETDEV_EVENT_4WAY_HANDSHAKE,
					netdev->user_data);
	} else
		netdev_set_linkmode_and_operstate(netdev->index, 1, IF_OPER_UP,
						netdev_operstate_cb, netdev);

	return;

error:
	if (netdev->connect_cb)
		netdev->connect_cb(netdev, NETDEV_RESULT_ASSOCIATION_FAILED,
						netdev->user_data);
}

static void netdev_cmd_associate_cb(struct l_genl_msg *msg, void *user_data)
{
	struct netdev *netdev = user_data;

	/* Wait for associate event */
	if (l_genl_msg_get_error(msg) >= 0) {
		if (netdev->event_filter)
			netdev->event_filter(netdev,
						NETDEV_EVENT_ASSOCIATING,
						netdev->user_data);

		return;
	}

	if (netdev->connect_cb)
		netdev->connect_cb(netdev, NETDEV_RESULT_ASSOCIATION_FAILED,
						netdev->user_data);
}

static struct l_genl_msg *netdev_build_cmd_associate(struct netdev *netdev,
							struct scan_bss *bss,
							struct eapol_sm *sm)
{
	struct l_genl_msg *msg;

	msg = l_genl_msg_new_sized(NL80211_CMD_ASSOCIATE, 512);
	l_genl_msg_append_attr(msg, NL80211_ATTR_IFINDEX, 4, &netdev->index);
	l_genl_msg_append_attr(msg, NL80211_ATTR_WIPHY_FREQ,
						4, &bss->frequency);
	l_genl_msg_append_attr(msg, NL80211_ATTR_MAC, ETH_ALEN, bss->addr);
	l_genl_msg_append_attr(msg, NL80211_ATTR_SSID,
						bss->ssid_len, bss->ssid);

	if (sm) {
		uint32_t cipher;
		uint32_t nl_cipher;
		size_t ie_len;
		const uint8_t *ie;

		cipher = eapol_sm_get_pairwise_cipher(sm);
		if (cipher == IE_RSN_CIPHER_SUITE_CCMP)
			nl_cipher = CRYPTO_CIPHER_CCMP;
		else
			nl_cipher = CRYPTO_CIPHER_TKIP;

		l_genl_msg_append_attr(msg, NL80211_ATTR_CIPHER_SUITES_PAIRWISE,
					4, &nl_cipher);

		cipher = eapol_sm_get_group_cipher(sm);
		if (cipher == IE_RSN_CIPHER_SUITE_CCMP)
			nl_cipher = CRYPTO_CIPHER_CCMP;
		else
			nl_cipher = CRYPTO_CIPHER_TKIP;

		l_genl_msg_append_attr(msg, NL80211_ATTR_CIPHER_SUITE_GROUP,
					4, &nl_cipher);

		l_genl_msg_append_attr(msg, NL80211_ATTR_CONTROL_PORT, 0, NULL);

		ie = eapol_sm_get_own_ie(sm, &ie_len);
		if (ie)
			l_genl_msg_append_attr(msg, NL80211_ATTR_IE,
								ie_len, ie);
	}

	return msg;
}

static void netdev_authenticate_event(struct l_genl_msg *msg,
							struct netdev *netdev)
{
	struct l_genl_attr attr;
	uint16_t type, len;
	const void *data;
	int err;

	l_debug("");

	err = l_genl_msg_get_error(msg);
	if (err < 0) {
		l_error("authentication failed %s (%d)", strerror(-err), err);
		goto error;
	}

	if (!l_genl_attr_init(&attr, msg)) {
		l_debug("attr init failed");
		goto error;
	}

	while (l_genl_attr_next(&attr, &type, &len, &data)) {
		switch (type) {
		case NL80211_ATTR_TIMED_OUT:
			l_warn("authentication timed out");
			goto error;
		}
	}

	if (!netdev->associate_msg)
		return;

	if (l_genl_family_send(nl80211, netdev->associate_msg,
				netdev_cmd_associate_cb, netdev, NULL) > 0) {
		netdev->associate_msg = NULL;
		return;
	}

	l_genl_msg_unref(netdev->associate_msg);
	netdev->associate_msg = NULL;

error:
	if (netdev->connect_cb)
		netdev->connect_cb(netdev, NETDEV_RESULT_AUTHENTICATION_FAILED,
						netdev->user_data);
}

static void netdev_cmd_authenticate_cb(struct l_genl_msg *msg, void *user_data)
{
	struct netdev *netdev = user_data;

	if (l_genl_msg_get_error(msg) >= 0) {
		if (netdev->event_filter)
			netdev->event_filter(netdev,
						NETDEV_EVENT_AUTHENTICATING,
						netdev->user_data);

		return;
	}

	if (netdev->connect_cb)
		netdev->connect_cb(netdev, NETDEV_RESULT_AUTHENTICATION_FAILED,
						netdev->user_data);
}

static struct l_genl_msg *netdev_build_cmd_authenticate(struct netdev *netdev,
							struct scan_bss *bss)
{
	uint32_t auth_type = NL80211_AUTHTYPE_OPEN_SYSTEM;
	struct l_genl_msg *msg;

	msg = l_genl_msg_new_sized(NL80211_CMD_AUTHENTICATE, 512);
	l_genl_msg_append_attr(msg, NL80211_ATTR_IFINDEX, 4, &netdev->index);
	l_genl_msg_append_attr(msg, NL80211_ATTR_WIPHY_FREQ,
						4, &bss->frequency);
	l_genl_msg_append_attr(msg, NL80211_ATTR_MAC, ETH_ALEN, bss->addr);
	l_genl_msg_append_attr(msg, NL80211_ATTR_SSID,
						bss->ssid_len, bss->ssid);
	l_genl_msg_append_attr(msg, NL80211_ATTR_AUTH_TYPE, 4, &auth_type);

	return msg;
}

int netdev_connect(struct netdev *netdev, struct scan_bss *bss,
				struct eapol_sm *sm,
				netdev_event_func_t event_filter,
				netdev_connect_cb_t cb, void *user_data)
{
	struct l_genl_msg *authenticate;
	struct l_genl_msg *associate;

	authenticate = netdev_build_cmd_authenticate(netdev, bss);
	if (!authenticate)
		return -EINVAL;

	associate = netdev_build_cmd_associate(netdev, bss, sm);
	if (!associate) {
		l_genl_msg_unref(authenticate);
		return -EINVAL;
	}

	if (!l_genl_family_send(nl80211, authenticate,
				netdev_cmd_authenticate_cb, netdev, NULL)) {
		l_genl_msg_unref(associate);
		l_genl_msg_unref(authenticate);
		return -EIO;
	}

	netdev->event_filter = event_filter;
	netdev->connect_cb = cb;
	netdev->user_data = user_data;
	netdev->sm = sm;
	netdev->associate_msg = associate;
	memcpy(netdev->remote_addr, bss->addr, ETH_ALEN);

	return 0;
}

int netdev_disconnect(struct netdev *netdev,
				netdev_disconnect_cb_t cb, void *user_data)
{
	return 0;
}

static void netdev_mlme_notify(struct l_genl_msg *msg, void *user_data)
{
	struct netdev *netdev = NULL;
	struct l_genl_attr attr;
	uint16_t type, len;
	const void *data;
	uint8_t cmd;

	cmd = l_genl_msg_get_command(msg);

	l_debug("MLME notification %u", cmd);

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

	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;
			}

			netdev = netdev_find(*((uint32_t *) data));
			break;
		}
	}

	if (!netdev) {
		l_warn("MLME notification is missing ifindex attribute");
		return;
	}

	switch (cmd) {
	case NL80211_CMD_AUTHENTICATE:
		netdev_authenticate_event(msg, netdev);
		break;
	case NL80211_CMD_DEAUTHENTICATE:
		netdev_deauthenticate_event(msg, netdev);
		break;
	case NL80211_CMD_ASSOCIATE:
		netdev_associate_event(msg, netdev);
		break;
	case NL80211_CMD_DISCONNECT:
		netdev_disconnect_event(msg, netdev);
		break;
	case NL80211_CMD_NOTIFY_CQM:
		netdev_cqm_event(msg, netdev);
		break;
	}
}

static void netdev_get_interface_callback(struct l_genl_msg *msg,
								void *user_data)
{
	struct l_genl_attr attr;
	uint16_t type, len;
	const void *data;
	const char *ifname;
	uint16_t ifname_len;
	const uint8_t *ifaddr;
	const uint32_t *ifindex, *iftype;
	struct netdev *netdev;
	struct wiphy *wiphy = NULL;

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

	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 = data;
			break;

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

			ifname = data;
			ifname_len = len;
			break;

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

			wiphy = wiphy_find(*((uint32_t *) data));
			break;

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

			iftype = data;
			break;

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

			ifaddr = data;
			break;
		}
	}

	if (!wiphy) {
		l_warn("Missing wiphy attribute or wiphy not found");
		return;
	}

	if (!ifindex || !ifaddr | !ifname) {
		l_warn("Unable to parse interface information");
		return;
	}

	if (netdev_find(*ifindex)) {
		l_debug("Skipping duplicate netdev %s[%d]", ifname, *ifindex);
		return;
	}

	netdev = l_new(struct netdev, 1);
	netdev->index = *ifindex;
	netdev->type = *iftype;
	memcpy(netdev->addr, ifaddr, sizeof(netdev->addr));
	memcpy(netdev->name, ifname, ifname_len);

	l_queue_push_tail(netdev_list, netdev);

	l_debug("Found interface %s[%d]", netdev->name, netdev->index);
	device_create(wiphy, netdev);
}

static void netdev_config_notify(struct l_genl_msg *msg, void *user_data)
{
	struct l_genl_attr attr;
	uint16_t type, len;
	const void *data;
	uint8_t cmd;

	cmd = l_genl_msg_get_command(msg);

	l_debug("Notification of command %u", cmd);

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

	switch (cmd) {
	case NL80211_CMD_NEW_INTERFACE:
	case NL80211_CMD_DEL_INTERFACE:
	{
		const uint32_t *wiphy_id = NULL;
		const uint32_t *ifindex = NULL;

		while (l_genl_attr_next(&attr, &type, &len, &data)) {
			switch (type) {
			case NL80211_ATTR_WIPHY:
				if (len != sizeof(uint32_t)) {
					l_warn("Invalid wiphy attribute");
					return;
				}

				wiphy_id = data;
				break;

			case NL80211_ATTR_IFINDEX:
				if (len != sizeof(uint32_t)) {
					l_warn("Invalid ifindex attribute");
					return;
				}

				ifindex = data;
				break;
			}
		}

		if (!wiphy_id || !ifindex)
			return;

		if (cmd == NL80211_CMD_NEW_INTERFACE)
			l_info("New interface %d added", *ifindex);
		else
			l_info("Interface %d removed", *ifindex);

		break;
	}
	}
}

bool netdev_init(struct l_genl_family *in)
{
	struct l_genl_msg *msg;

	if (rtnl)
		return false;

	l_debug("Opening route netlink socket");

	rtnl = l_netlink_new(NETLINK_ROUTE);
	if (!rtnl) {
		l_error("Failed to open route netlink socket");
		return false;
	}

	if (getenv("IWD_RTNL_DEBUG"))
		l_netlink_set_debug(rtnl, do_debug, "[RTNL] ", NULL);

	netdev_list = l_queue_new();

	nl80211 = in;

	if (!l_genl_family_register(nl80211, "config", netdev_config_notify,
								NULL, NULL))
		l_error("Registering for config notification failed");

	msg = l_genl_msg_new(NL80211_CMD_GET_INTERFACE);
	if (!l_genl_family_dump(nl80211, msg, netdev_get_interface_callback,
								NULL, NULL))
		l_error("Getting all interface information failed");

	if (!l_genl_family_register(nl80211, "mlme", netdev_mlme_notify,
								NULL, NULL))
		l_error("Registering for MLME notification failed");

	__eapol_set_deauthenticate_func(netdev_handshake_failed);

	return true;
}

bool netdev_exit(void)
{
	if (!rtnl)
		return false;

	nl80211 = NULL;

	l_queue_destroy(netdev_list, netdev_free);
	netdev_list = NULL;

	l_debug("Closing route netlink socket");
	l_netlink_destroy(rtnl);
	rtnl = NULL;

	return true;
}