iwd/src/dpp.c

/*
 *
 *  Wireless daemon for Linux
 *
 *  Copyright (C) 2021  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 <ell/ell.h>

#include "src/dbus.h"
#include "src/netdev.h"
#include "src/module.h"
#include "src/dpp-util.h"
#include "src/band.h"

static uint32_t netdev_watch;

struct dpp_sm {
	struct netdev *netdev;
	char *uri;

	uint64_t wdev_id;

	uint8_t *pub_asn1;
	size_t pub_asn1_len;
	uint8_t pub_boot_hash[32];
	const struct l_ecc_curve *curve;
	size_t key_len;
	size_t nonce_len;
	struct l_ecc_scalar *boot_private;
	struct l_ecc_point *boot_public;
};

static void dpp_reset(struct dpp_sm *dpp)
{
	if (dpp->uri) {
		l_free(dpp->uri);
		dpp->uri = NULL;
	}
}

static void dpp_free(struct dpp_sm *dpp)
{
	dpp_reset(dpp);

	if (dpp->pub_asn1) {
		l_free(dpp->pub_asn1);
		dpp->pub_asn1 = NULL;
	}

	if (dpp->boot_public) {
		l_ecc_point_free(dpp->boot_public);
		dpp->boot_public = NULL;
	}

	if (dpp->boot_private) {
		l_ecc_scalar_free(dpp->boot_private);
		dpp->boot_private = NULL;
	}

	l_free(dpp);
}

static void dpp_create(struct netdev *netdev)
{
	struct l_dbus *dbus = dbus_get_bus();
	struct dpp_sm *dpp = l_new(struct dpp_sm, 1);

	dpp->netdev = netdev;
	dpp->curve = l_ecc_curve_from_ike_group(19);
	dpp->key_len = l_ecc_curve_get_scalar_bytes(dpp->curve);
	dpp->nonce_len = dpp_nonce_len_from_key_len(dpp->key_len);

	l_ecdh_generate_key_pair(dpp->curve, &dpp->boot_private,
					&dpp->boot_public);

	dpp->pub_asn1 = dpp_point_to_asn1(dpp->boot_public, &dpp->pub_asn1_len);

	dpp_hash(L_CHECKSUM_SHA256, dpp->pub_boot_hash, 1,
			dpp->pub_asn1, dpp->pub_asn1_len);

	l_dbus_object_add_interface(dbus, netdev_get_path(netdev),
					IWD_DPP_INTERFACE, dpp);
}

static void dpp_netdev_watch(struct netdev *netdev,
				enum netdev_watch_event event, void *userdata)
{
	switch (event) {
	case NETDEV_WATCH_EVENT_NEW:
	case NETDEV_WATCH_EVENT_UP:
		if (netdev_get_iftype(netdev) == NETDEV_IFTYPE_STATION &&
				netdev_get_is_up(netdev))
			dpp_create(netdev);
		break;
	case NETDEV_WATCH_EVENT_DEL:
	case NETDEV_WATCH_EVENT_DOWN:
		l_dbus_object_remove_interface(dbus_get_bus(),
						netdev_get_path(netdev),
						IWD_DPP_INTERFACE);
		break;
	default:
		break;
	}
}

static struct l_dbus_message *dpp_dbus_start_enrollee(struct l_dbus *dbus,
						struct l_dbus_message *message,
						void *user_data)
{
	struct dpp_sm *dpp = user_data;
	uint32_t freq = band_channel_to_freq(6, BAND_FREQ_2_4_GHZ);
	struct l_dbus_message *reply;

	dpp->uri = dpp_generate_uri(dpp->pub_asn1, dpp->pub_asn1_len, 2,
					netdev_get_address(dpp->netdev), &freq,
					1, NULL, NULL);

	l_debug("DPP Start Enrollee: %s", dpp->uri);

	reply = l_dbus_message_new_method_return(message);

	l_dbus_message_set_arguments(reply, "s", dpp->uri);

	return reply;
}

static struct l_dbus_message *dpp_dbus_stop(struct l_dbus *dbus,
						struct l_dbus_message *message,
						void *user_data)
{
	struct dpp_sm *dpp = user_data;

	dpp_reset(dpp);

	return l_dbus_message_new_method_return(message);
}

static void dpp_setup_interface(struct l_dbus_interface *interface)
{
	l_dbus_interface_method(interface, "StartEnrollee", 0,
				dpp_dbus_start_enrollee, "s", "", "uri");
	l_dbus_interface_method(interface, "Stop", 0,
				dpp_dbus_stop, "", "");
}

static void dpp_destroy_interface(void *user_data)
{
	struct dpp_sm *dpp = user_data;

	dpp_free(dpp);
}

static int dpp_init(void)
{
	netdev_watch = netdev_watch_add(dpp_netdev_watch, NULL, NULL);

	l_dbus_register_interface(dbus_get_bus(), IWD_DPP_INTERFACE,
					dpp_setup_interface,
					dpp_destroy_interface, false);
	return 0;
}

static void dpp_exit(void)
{
	l_debug("");

	netdev_watch_remove(netdev_watch);
}

IWD_MODULE(dpp, dpp_init, dpp_exit);
IWD_MODULE_DEPENDS(dpp, netdev);