source: mainline/uspace/lib/ieee80211/src/ieee80211.c@ 1dcc0b9

/*
 * Copyright (c) 2015 Jan Kolarik
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup libieee80211
 * @{
 */

/** @file ieee80211.c
 * 
 * IEEE 802.11 interface implementation.
 */

#include <stdio.h>
#include <crypto.h>
#include <str.h>
#include <macros.h>
#include <errno.h>

#include <ieee80211.h>
#include <ieee80211_impl.h>
#include <ieee80211_iface_impl.h>
#include <ieee80211_private.h>
#include <ops/ieee80211.h>

#define IEEE80211_DATA_RATES_SIZE 8
#define IEEE80211_EXT_DATA_RATES_SIZE 4

/** Frame encapsulation used in IEEE 802.11. */
static const uint8_t rfc1042_header[] = { 
        0xAA, 0xAA, 0x03, 0x00, 0x00, 0x00 
};

/** Broadcast MAC address used to spread probe request through channel. */
static const uint8_t ieee80211_broadcast_mac_addr[] = {
        0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF
};

/**
 * Check data frame.
 * 
 * @param frame_ctrl Frame control field in little endian (!).
 * 
 * @return True if it is data frame, otherwise false.
 */
inline bool ieee80211_is_data_frame(uint16_t frame_ctrl)
{
        frame_ctrl = uint16_t_le2host(frame_ctrl);
        
        return (frame_ctrl & IEEE80211_FRAME_CTRL_FRAME_TYPE)
                == IEEE80211_DATA_FRAME;
}

/**
 * Check management frame.
 * 
 * @param frame_ctrl Frame control field in little endian (!).
 * 
 * @return True if it is management frame, otherwise false.
 */
inline bool ieee80211_is_mgmt_frame(uint16_t frame_ctrl)
{
        frame_ctrl = uint16_t_le2host(frame_ctrl);
        
        return (frame_ctrl & IEEE80211_FRAME_CTRL_FRAME_TYPE)
                == IEEE80211_MGMT_FRAME;
}

/**
 * Check management beacon frame.
 * 
 * @param frame_ctrl Frame control field in little endian (!).
 * 
 * @return True if it is beacon frame, otherwise false.
 */
inline bool ieee80211_is_beacon_frame(uint16_t frame_ctrl)
{
        frame_ctrl = uint16_t_le2host(frame_ctrl);
        
        return (frame_ctrl & IEEE80211_FRAME_CTRL_FRAME_SUBTYPE)
                == IEEE80211_MGMT_BEACON_FRAME;
}

/**
 * Check management probe response frame.
 * 
 * @param frame_ctrl Frame control field in little endian (!).
 * 
 * @return True if it is probe resp frame, otherwise false.
 */
inline bool ieee80211_is_probe_response_frame(uint16_t frame_ctrl)
{
        frame_ctrl = uint16_t_le2host(frame_ctrl);
        
        return (frame_ctrl & IEEE80211_FRAME_CTRL_FRAME_SUBTYPE)
                == IEEE80211_MGMT_PROBE_RESP_FRAME;
}

/**
 * Check management authentication frame.
 * 
 * @param frame_ctrl Frame control field in little endian (!).
 * 
 * @return True if it is auth frame, otherwise false.
 */
inline bool ieee80211_is_auth_frame(uint16_t frame_ctrl)
{
        frame_ctrl = uint16_t_le2host(frame_ctrl);
        
        return (frame_ctrl & IEEE80211_FRAME_CTRL_FRAME_SUBTYPE)
                == IEEE80211_MGMT_AUTH_FRAME;
}

/**
 * Check management association response frame.
 * 
 * @param frame_ctrl Frame control field in little endian (!).
 * 
 * @return True if it is assoc resp frame, otherwise false.
 */
inline bool ieee80211_is_assoc_response_frame(uint16_t frame_ctrl)
{
        frame_ctrl = uint16_t_le2host(frame_ctrl);
        
        return (frame_ctrl & IEEE80211_FRAME_CTRL_FRAME_SUBTYPE)
                == IEEE80211_MGMT_ASSOC_RESP_FRAME;
}

/**
 * Check data frame "to distribution system" direction.
 * 
 * @param frame_ctrl Frame control field in little endian (!).
 * 
 * @return True if it is TODS frame, otherwise false.
 */
static inline bool ieee80211_is_tods_frame(uint16_t frame_ctrl)
{
        frame_ctrl = uint16_t_le2host(frame_ctrl);
        
        return (frame_ctrl & IEEE80211_FRAME_CTRL_TODS);
}

/**
 * Check data frame "from distribution system" direction.
 * 
 * @param frame_ctrl Frame control field in little endian (!).
 * 
 * @return True if it is FROMDS frame, otherwise false.
 */
static inline bool ieee80211_is_fromds_frame(uint16_t frame_ctrl)
{
        frame_ctrl = uint16_t_le2host(frame_ctrl);
        
        return (frame_ctrl & IEEE80211_FRAME_CTRL_FROMDS);
}

/**
 * Check if it is data frame containing payload data.
 * 
 * @param frame_ctrl Frame control field in little endian (!).
 * 
 * @return True if it has payload data, otherwise false.
 */
static inline bool ieee80211_has_data_frame(uint16_t frame_ctrl)
{
        frame_ctrl = uint16_t_le2host(frame_ctrl);
        
        return (frame_ctrl & (IEEE80211_FRAME_CTRL_FRAME_TYPE | 0x40))
                == IEEE80211_DATA_FRAME;
}

/**
 * Check if it is encrypted frame.
 * 
 * @param frame_ctrl Frame control field in little endian (!).
 * 
 * @return True if the frame is encrypted, otherwise false.
 */
static inline bool ieee80211_is_encrypted_frame(uint16_t frame_ctrl)
{
        frame_ctrl = uint16_t_le2host(frame_ctrl);
        
        return (frame_ctrl & IEEE80211_FRAME_CTRL_PROTECTED) != 0;
}

/**
 * Check if PAE packet is EAPOL-Key frame.
 * 
 * @param key_frame Pointer to start of EAPOL frame.
 * 
 * @return True if it is EAPOL-Key frame, otherwise false.
 */
static inline bool ieee80211_is_eapol_key_frame(ieee80211_eapol_key_frame_t 
        *key_frame)
{
        return (key_frame->packet_type == IEEE80211_EAPOL_KEY);
}


/**
 * Generate packet sequence number.
 * 
 * @param ieee80211_dev IEEE 802.11 device.
 * 
 * @return True if it has payload data, otherwise false.
 */
static uint16_t ieee80211_get_sequence_number(ieee80211_dev_t *ieee80211_dev)
{
        uint16_t ret_val = ieee80211_dev->sequence_number;
        ieee80211_dev->sequence_number += (1 << 4);
        return ret_val;
}

/**
 * Get driver-specific structure for IEEE 802.11 device.
 * 
 * @param ieee80211_dev IEEE 802.11 device.
 * 
 * @return Driver-specific structure.
 */
void *ieee80211_get_specific(ieee80211_dev_t* ieee80211_dev)
{
        return ieee80211_dev->specific;
}

/**
 * Set driver-specific structure for IEEE 802.11 device.
 * 
 * @param ieee80211_dev IEEE 802.11 device.
 * @param specific Driver-specific structure.
 */
void ieee80211_set_specific(ieee80211_dev_t* ieee80211_dev,
        void *specific)
{
        ieee80211_dev->specific = specific;
}

/**
 * Get related DDF device.
 * 
 * @param ieee80211_dev IEEE 802.11 device.
 * 
 * @return DDF device.
 */
ddf_dev_t *ieee80211_get_ddf_dev(ieee80211_dev_t* ieee80211_dev)
{
        return ieee80211_dev->ddf_dev;
}

/**
 * Query current operating mode of IEEE 802.11 device.
 * 
 * @param ieee80211_dev IEEE 802.11 device.
 * 
 * @return Current IEEE 802.11 operating mode.
 */
ieee80211_operating_mode_t ieee80211_query_current_op_mode(ieee80211_dev_t* 
        ieee80211_dev)
{
        return ieee80211_dev->current_op_mode;
}

/**
 * Query current frequency of IEEE 802.11 device.
 * 
 * @param ieee80211_dev IEEE 802.11 device.
 * 
 * @return Current device operating frequency.
 */
uint16_t ieee80211_query_current_freq(ieee80211_dev_t* ieee80211_dev)
{
        return ieee80211_dev->current_freq;
}

/**
 * Query BSSID the device is connected to.
 * 
 * @param ieee80211_dev IEEE 802.11 device.
 * @param bssid Pointer to structure where should be stored BSSID.
 */
void ieee80211_query_bssid(ieee80211_dev_t* ieee80211_dev, 
        nic_address_t *bssid)
{
        if(bssid) {
                ieee80211_scan_result_t *auth_data =
                        &ieee80211_dev->bssid_info.res_link->scan_result;
                
                memcpy(bssid, (void *)&auth_data->bssid, sizeof(nic_address_t));
        }
}

/**
 * Get AID of network we are connected to.
 * 
 * @param ieee80211_dev IEEE 802.11 device.
 * 
 * @return AID.
 */
uint16_t ieee80211_get_aid(ieee80211_dev_t* ieee80211_dev)
{
        return ieee80211_dev->bssid_info.aid;
}

/**
 * Get security suite used for HW encryption. 
 * 
 * @param ieee80211_dev IEEE 802.11 device.
 * 
 * @return Security suite indicator.
 */
int ieee80211_get_security_suite(ieee80211_dev_t* ieee80211_dev)
{
        ieee80211_scan_result_link_t *auth_link = 
                ieee80211_dev->bssid_info.res_link;
        
        return auth_link->scan_result.security.pair_alg;
}

/**
 * Check if IEEE 802.11 device is connected to network.
 * 
 * @param ieee80211_dev IEEE 802.11 device.
 * 
 * @return True if device is connected to network, otherwise false.
 */
bool ieee80211_is_connected(ieee80211_dev_t* ieee80211_dev)
{
        return ieee80211_dev->current_auth_phase == IEEE80211_AUTH_ASSOCIATED;
}

/**
 * Report current operating mode for IEEE 802.11 device.
 * 
 * @param ieee80211_dev IEEE 802.11 device.
 * @param op_mode Current IEEE 802.11 operating mode.
 */
void ieee80211_report_current_op_mode(ieee80211_dev_t* ieee80211_dev,
        ieee80211_operating_mode_t op_mode)
{
        ieee80211_dev->current_op_mode = op_mode;
}

/**
 * Report current frequency for IEEE 802.11 device.
 * 
 * @param ieee80211_dev IEEE 802.11 device.
 * @param freq Current device operating frequency.
 */
void ieee80211_report_current_freq(ieee80211_dev_t* ieee80211_dev,
        uint16_t freq)
{
        ieee80211_dev->current_freq = freq;
}

/**
 * Check if IEEE 802.11 device is ready (fully initialized).
 * 
 * @param ieee80211_dev IEEE 802.11 device.
 * 
 * @return True if device is ready to work, otherwise false.
 */
bool ieee80211_is_ready(ieee80211_dev_t* ieee80211_dev)
{
        fibril_mutex_lock(&ieee80211_dev->gen_mutex);
        bool ready_state = ieee80211_dev->ready;
        fibril_mutex_unlock(&ieee80211_dev->gen_mutex);
        
        return ready_state;
}

/**
 * Set IEEE 802.11 device to ready state.
 * 
 * @param ieee80211_dev IEEE 802.11 device.
 * @param ready Ready state to be set.
 */
void ieee80211_set_ready(ieee80211_dev_t* ieee80211_dev, bool ready)
{
        fibril_mutex_lock(&ieee80211_dev->gen_mutex);
        ieee80211_dev->ready = ready;
        fibril_mutex_unlock(&ieee80211_dev->gen_mutex);
}

extern bool ieee80211_query_using_key(ieee80211_dev_t* ieee80211_dev)
{
        return ieee80211_dev->using_hw_key;
}

void ieee80211_setup_key_confirm(ieee80211_dev_t* ieee80211_dev, 
        bool using_key)
{
        ieee80211_dev->using_hw_key = using_key;
}

/**
 * Implementation of NIC open callback for IEEE 802.11 devices.
 * 
 * @param fun NIC function.
 * 
 * @return EOK if succeed, negative error code otherwise.
 */
static int ieee80211_open(ddf_fun_t *fun)
{
        nic_t *nic_data = nic_get_from_ddf_fun(fun);
        ieee80211_dev_t *ieee80211_dev = nic_get_specific(nic_data);
        
        if(ieee80211_dev->started) {
                return EOK;
        } else {
                ieee80211_dev->started = true;
        }
        
        int rc = ieee80211_dev->ops->start(ieee80211_dev);
        if(rc != EOK)
                return rc;
        
        rc = ieee80211_dev->ops->scan(ieee80211_dev);
        if(rc != EOK)
                return rc;
        
        return EOK;
}

/**
 * Send frame handler.
 * 
 * @param nic Pointer to NIC device.
 * @param data Data buffer.
 * @param size Data buffer size.
 */
static void ieee80211_send_frame(nic_t *nic, void *data, size_t size)
{
        ieee80211_dev_t *ieee80211_dev = (ieee80211_dev_t *) 
                nic_get_specific(nic);
        
        if(!ieee80211_is_connected(ieee80211_dev)) {
                return;
        }
        
        ieee80211_scan_result_t *auth_data =
                        &ieee80211_dev->bssid_info.res_link->scan_result;
        
        /* We drop part of IEEE 802.3 ethernet header. */
        size_t drop_bytes = sizeof(eth_header_t) - 2;
        
        size_t complete_size = (size - drop_bytes) + 
                sizeof(ieee80211_data_header_t) +
                ARRAY_SIZE(rfc1042_header);
        
        /* Init crypto data. */
        size_t add_size = 0;
        uint16_t crypto = 0;
        uint8_t add_data[8];
        memset(add_data, 0, 8);
        
        if(ieee80211_dev->using_hw_key) {
                int sec_suite = auth_data->security.pair_alg;
                switch(sec_suite) {
                        case IEEE80211_SECURITY_SUITE_CCMP:
                                add_size = IEEE80211_CCMP_HEADER_LENGTH;
                                add_data[3] = 0x20;
                                break;
                        default:
                                break;
                }

                crypto = uint16_t_le2host(IEEE80211_FRAME_CTRL_PROTECTED);
        }
        
        complete_size += add_size;
        
        void *complete_buffer = malloc(complete_size);
        memset(complete_buffer, 0, complete_size);
        
        if(add_size) {
                memcpy(complete_buffer + sizeof(ieee80211_data_header_t),
                        add_data, add_size);
        }
        
        memcpy(complete_buffer + sizeof(ieee80211_data_header_t) + add_size,
                rfc1042_header,
                ARRAY_SIZE(rfc1042_header));
        
        memcpy(complete_buffer + 
                sizeof(ieee80211_data_header_t) +
                ARRAY_SIZE(rfc1042_header) + add_size, 
                data + drop_bytes, size - drop_bytes);
        
        ieee80211_data_header_t *data_header =
                (ieee80211_data_header_t *) complete_buffer;
        data_header->frame_ctrl = 
                uint16_t_le2host(IEEE80211_DATA_FRAME) |
                uint16_t_le2host(IEEE80211_DATA_DATA_FRAME) |
                uint16_t_le2host(IEEE80211_FRAME_CTRL_TODS) |
                crypto;
        data_header->seq_ctrl = ieee80211_get_sequence_number(ieee80211_dev);
        
        /* BSSID, SA, DA. */
        memcpy(data_header->address1, auth_data->bssid.address, ETH_ADDR);
        memcpy(data_header->address2, data + ETH_ADDR, ETH_ADDR);
        memcpy(data_header->address3, data, ETH_ADDR);
        
        ieee80211_dev->ops->tx_handler(ieee80211_dev, 
                complete_buffer, 
                complete_size);
        
        free(complete_buffer);
}

/**
 * Fill out IEEE 802.11 device functions implementations.
 * 
 * @param ieee80211_dev IEEE 802.11 device.
 * @param ieee80211_ops Callbacks implementation.
 * @param ieee80211_iface Interface functions implementation.
 * @param nic_iface NIC interface functions implementation.
 * @param nic_dev_ops NIC device functions implementation.
 * 
 * @return EINVAL when missing pointer to ieee80211_ops or ieee80211_iface,
 * otherwise EOK.
 */
static int ieee80211_implement(ieee80211_dev_t *ieee80211_dev, 
        ieee80211_ops_t *ieee80211_ops, ieee80211_iface_t *ieee80211_iface,
        nic_iface_t *nic_iface, ddf_dev_ops_t *nic_dev_ops)
{
        if(ieee80211_ops) {
                if(!ieee80211_ops->start)
                        ieee80211_ops->start = ieee80211_start_impl;

                if(!ieee80211_ops->tx_handler)
                        ieee80211_ops->tx_handler = ieee80211_tx_handler_impl;

                if(!ieee80211_ops->set_freq)
                        ieee80211_ops->set_freq = ieee80211_set_freq_impl;
                
                if(!ieee80211_ops->bssid_change)
                        ieee80211_ops->bssid_change = 
                                ieee80211_bssid_change_impl;
                
                if(!ieee80211_ops->key_config)
                        ieee80211_ops->key_config = ieee80211_key_config_impl;
                
                if(!ieee80211_ops->scan)
                        ieee80211_ops->scan = ieee80211_scan_impl;
        } else {
                return EINVAL;
        }
        
        ieee80211_dev->ops = ieee80211_ops;
        
        if(ieee80211_iface) {
                if(nic_dev_ops)
                        if (!nic_dev_ops->interfaces[IEEE80211_DEV_IFACE])
                                nic_dev_ops->interfaces[IEEE80211_DEV_IFACE] = 
                                        ieee80211_iface;
                
                if(!ieee80211_iface->get_scan_results)
                        ieee80211_iface->get_scan_results = 
                                ieee80211_get_scan_results_impl;
                
                if(!ieee80211_iface->connect)
                        ieee80211_iface->connect = ieee80211_connect_impl;
                
                if(!ieee80211_iface->disconnect)
                        ieee80211_iface->disconnect = ieee80211_disconnect_impl;
        } else {
                return EINVAL;
        }
        
        if(nic_dev_ops) {
                if(!nic_dev_ops->open)
                        nic_dev_ops->open = ieee80211_open;
        } else {
                return EINVAL;
        }
        
        ieee80211_dev->iface = ieee80211_iface;
        
        nic_driver_implement(NULL, nic_dev_ops, nic_iface);
        
        return EOK;
}

/**
 * Allocate IEEE802.11 device structure.
 * 
 * @return Pointer to allocated IEEE802.11 device structure.
 */
ieee80211_dev_t *ieee80211_device_create()
{
        return calloc(1, sizeof(ieee80211_dev_t));
}

/**
 * Initialize an IEEE802.11 framework structure.
 * 
 * @param ieee80211_dev Device structure to initialize.
 * @param ddf_dev Pointer to backing DDF device structure.
 * 
 * @return EOK if succeed, negative error code otherwise.
 */
int ieee80211_device_init(ieee80211_dev_t *ieee80211_dev, ddf_dev_t *ddf_dev)
{
        ieee80211_dev->ddf_dev = ddf_dev;
        ieee80211_dev->started = false;
        ieee80211_dev->ready = false;
        ieee80211_dev->using_hw_key = false;
        ieee80211_dev->current_op_mode = IEEE80211_OPMODE_STATION;
        ieee80211_dev->current_auth_phase = IEEE80211_AUTH_DISCONNECTED;
        memcpy(ieee80211_dev->bssid_mask.address, ieee80211_broadcast_mac_addr, 
                ETH_ADDR);
        
        ieee80211_scan_result_list_init(&ieee80211_dev->ap_list);
        
        fibril_mutex_initialize(&ieee80211_dev->gen_mutex);
        fibril_condvar_initialize(&ieee80211_dev->gen_cond);
        
        /* Bind NIC to device */
        nic_t *nic = nic_create_and_bind(ddf_dev);
        if (!nic) {
                return ENOMEM;
        }
        
        nic_set_specific(nic, ieee80211_dev);
        
        return EOK;
}

/**
 * IEEE802.11 WiFi framework initialization.
 * 
 * @param ieee80211_dev Device structure to initialize.
 * @param ieee80211_ops Structure with implemented IEEE802.11 device operations.
 * @param ieee80211_iface Structure with implemented IEEE802.11 interface 
 * operations.
 * 
 * @return EOK if succeed, negative error code otherwise.
 */
int ieee80211_init(ieee80211_dev_t *ieee80211_dev, 
        ieee80211_ops_t *ieee80211_ops, ieee80211_iface_t *ieee80211_iface,
        nic_iface_t *ieee80211_nic_iface, ddf_dev_ops_t *ieee80211_nic_dev_ops)
{
        int rc = ieee80211_implement(ieee80211_dev, 
                ieee80211_ops, ieee80211_iface,
                ieee80211_nic_iface, ieee80211_nic_dev_ops);
        if(rc != EOK) {
                return rc;
        }
        
        nic_t *nic = nic_get_from_ddf_dev(ieee80211_dev->ddf_dev);
        
        /** TODO: Set NIC handlers here. */
        nic_set_send_frame_handler(nic, ieee80211_send_frame);
        
        ddf_fun_t *fun = ddf_fun_create(ieee80211_dev->ddf_dev, fun_exposed, 
                "port0");
        if (fun == NULL) {
                return EINVAL;
        }
        
        nic_set_ddf_fun(nic, fun);
        ddf_fun_set_ops(fun, ieee80211_nic_dev_ops);
        
        rc = ddf_fun_bind(fun);
        if (rc != EOK) {
                ddf_fun_destroy(fun);
                return rc;
        }
        rc = ddf_fun_add_to_category(fun, DEVICE_CATEGORY_NIC);
        if (rc != EOK) {
                ddf_fun_unbind(fun);
                return rc;
        }
        rc = ddf_fun_add_to_category(fun, DEVICE_CATEGORY_IEEE80211);
        if (rc != EOK) {
                ddf_fun_unbind(fun);
                return rc;
        }
        
        return EOK;
}

/**
 * Convert frequency value to channel number.
 * 
 * @param freq IEEE 802.11 operating frequency.
 * 
 * @return Operating channel number.
 */
static uint8_t ieee80211_freq_to_channel(uint16_t freq)
{
        return (freq - IEEE80211_FIRST_FREQ) / IEEE80211_CHANNEL_GAP + 1;
}

static void ieee80211_prepare_ie_header(void **ie_header,
        uint8_t id, uint8_t length, void *data)
{
        ieee80211_ie_header_t *header =
                (ieee80211_ie_header_t *) *ie_header;
        
        header->element_id = id;
        header->length = length;
        
        memcpy(*ie_header + sizeof(ieee80211_ie_header_t), data, length);
        
        *ie_header = (void *) ((void *) header + 
                sizeof(ieee80211_ie_header_t) + length);
}

/**
 * Probe request implementation.
 * 
 * @param ieee80211_dev Pointer to IEEE 802.11 device structure.
 * @param ssid Probing SSID or NULL if broadcast.
 * 
 * @return EOK if succeed, negative error code otherwise.
 */
int ieee80211_probe_request(ieee80211_dev_t *ieee80211_dev, char *ssid)
{
        nic_t *nic = nic_get_from_ddf_dev(ieee80211_dev->ddf_dev);
        nic_address_t nic_address;
        nic_query_address(nic, &nic_address);
        
        size_t ssid_data_size = (ssid != NULL) ? str_size(ssid) : 0;
        size_t channel_data_size = 1;
        
        uint8_t channel = 
                ieee80211_freq_to_channel(ieee80211_dev->current_freq);
        
        /* 4 headers - (ssid, rates, ext rates, current channel) and their data
         * lengths. 
         */
        size_t payload_size = 
                sizeof(ieee80211_ie_header_t) * 4 +
                ssid_data_size + 
                IEEE80211_DATA_RATES_SIZE + IEEE80211_EXT_DATA_RATES_SIZE + 
                channel_data_size;
        
        size_t buffer_size = sizeof(ieee80211_mgmt_header_t) + payload_size;
        void *buffer = malloc(buffer_size);
        memset(buffer, 0, buffer_size);
        
        ieee80211_mgmt_header_t *mgmt_header = 
                (ieee80211_mgmt_header_t *) buffer;
        
        mgmt_header->frame_ctrl = host2uint16_t_le(
                IEEE80211_MGMT_FRAME | 
                IEEE80211_MGMT_PROBE_REQ_FRAME
                );
        memcpy(mgmt_header->dest_addr, ieee80211_broadcast_mac_addr, ETH_ADDR);
        memcpy(mgmt_header->src_addr, nic_address.address, ETH_ADDR);
        memcpy(mgmt_header->bssid, ieee80211_broadcast_mac_addr, ETH_ADDR);
        mgmt_header->seq_ctrl = 
                host2uint16_t_le(ieee80211_get_sequence_number(ieee80211_dev));
        
        /* Jump to payload. */
        void *it = (void *) buffer + sizeof(ieee80211_mgmt_header_t);
        ieee80211_prepare_ie_header(&it, IEEE80211_SSID_IE, ssid_data_size, 
                (void *) ssid);
        ieee80211_prepare_ie_header(&it, IEEE80211_RATES_IE, 
                IEEE80211_DATA_RATES_SIZE, 
                (void *) &ieee80211bg_data_rates);
        ieee80211_prepare_ie_header(&it, IEEE80211_EXT_RATES_IE, 
                IEEE80211_EXT_DATA_RATES_SIZE, 
                (void *) &ieee80211bg_data_rates[IEEE80211_DATA_RATES_SIZE]);
        ieee80211_prepare_ie_header(&it, IEEE80211_CHANNEL_IE, 
                channel_data_size, (void *) &channel);
        
        ieee80211_dev->ops->tx_handler(ieee80211_dev, buffer, buffer_size);
        
        free(buffer);
        
        return EOK;
}

/**
 * IEEE 802.11 authentication implementation.
 * 
 * @param ieee80211_dev Pointer to IEEE 802.11 device structure.
 * 
 * @return EOK if succeed, negative error code otherwise.
 */
int ieee80211_authenticate(ieee80211_dev_t *ieee80211_dev)
{
        nic_t *nic = nic_get_from_ddf_dev(ieee80211_dev->ddf_dev);
        nic_address_t nic_address;
        nic_query_address(nic, &nic_address);
        
        ieee80211_scan_result_t *auth_data =
                &ieee80211_dev->bssid_info.res_link->scan_result;
        
        size_t buffer_size = sizeof(ieee80211_mgmt_header_t) + 
                sizeof(ieee80211_auth_body_t);
        
        void *buffer = malloc(buffer_size);
        memset(buffer, 0, buffer_size);
        
        ieee80211_mgmt_header_t *mgmt_header = 
                (ieee80211_mgmt_header_t *) buffer;
        
        mgmt_header->frame_ctrl = host2uint16_t_le(
                IEEE80211_MGMT_FRAME | 
                IEEE80211_MGMT_AUTH_FRAME
                );
        memcpy(mgmt_header->dest_addr, auth_data->bssid.address, ETH_ADDR);
        memcpy(mgmt_header->src_addr, nic_address.address, ETH_ADDR);
        memcpy(mgmt_header->bssid, auth_data->bssid.address, ETH_ADDR);
        
        ieee80211_auth_body_t *auth_body =
                (ieee80211_auth_body_t *) 
                (buffer + sizeof(ieee80211_mgmt_header_t));
        auth_body->auth_alg = host2uint16_t_le(0);
        auth_body->auth_trans_no = host2uint16_t_le(1);
        
        ieee80211_dev->ops->tx_handler(ieee80211_dev, buffer, buffer_size);
        
        free(buffer);
        
        return EOK;
}

/** 
 * IEEE 802.11 association implementation.
 * 
 * @param ieee80211_dev Pointer to IEEE 802.11 device structure.
 * @param password Passphrase to be used in encrypted communication or NULL
 * for open networks.
 * 
 * @return EOK if succeed, negative error code otherwise.
 */
int ieee80211_associate(ieee80211_dev_t *ieee80211_dev, char *password) 
{
        nic_t *nic = nic_get_from_ddf_dev(ieee80211_dev->ddf_dev);
        nic_address_t nic_address;
        nic_query_address(nic, &nic_address);
        
        ieee80211_scan_result_link_t *auth_link =
                ieee80211_dev->bssid_info.res_link;
        
        ieee80211_scan_result_t *auth_data = &auth_link->scan_result;
        
        size_t ssid_data_size = str_size(auth_data->ssid);
        
        size_t payload_size = 
                sizeof(ieee80211_ie_header_t) * 3 +
                ssid_data_size + 
                IEEE80211_DATA_RATES_SIZE + 
                IEEE80211_EXT_DATA_RATES_SIZE;
        
        size_t buffer_size = 
                sizeof(ieee80211_mgmt_header_t) + 
                sizeof(ieee80211_assoc_req_body_t) +
                payload_size;
        
        if(auth_data->security.type == IEEE80211_SECURITY_WPA2) {
                buffer_size += auth_link->rsn_copy_len;
        }
        
        void *buffer = malloc(buffer_size);
        memset(buffer, 0, buffer_size);
        
        ieee80211_mgmt_header_t *mgmt_header = 
                (ieee80211_mgmt_header_t *) buffer;
        
        mgmt_header->frame_ctrl = host2uint16_t_le(
                IEEE80211_MGMT_FRAME | 
                IEEE80211_MGMT_ASSOC_REQ_FRAME
                );
        memcpy(mgmt_header->dest_addr, auth_data->bssid.address, ETH_ADDR);
        memcpy(mgmt_header->src_addr, nic_address.address, ETH_ADDR);
        memcpy(mgmt_header->bssid, auth_data->bssid.address, ETH_ADDR);
        
        ieee80211_assoc_req_body_t *assoc_body =
                (ieee80211_assoc_req_body_t *) 
                (buffer + sizeof(ieee80211_mgmt_header_t));
        assoc_body->listen_interval = host2uint16_t_le(1);
        
        /* Jump to payload. */
        void *it = buffer + sizeof(ieee80211_mgmt_header_t) +
                sizeof(ieee80211_assoc_req_body_t);
        ieee80211_prepare_ie_header(&it, IEEE80211_SSID_IE, 
                ssid_data_size, (void *) auth_data->ssid);
        ieee80211_prepare_ie_header(&it, IEEE80211_RATES_IE, 
                IEEE80211_DATA_RATES_SIZE, 
                (void *) &ieee80211bg_data_rates);
        ieee80211_prepare_ie_header(&it, IEEE80211_EXT_RATES_IE, 
                IEEE80211_EXT_DATA_RATES_SIZE, 
                (void *) &ieee80211bg_data_rates[IEEE80211_DATA_RATES_SIZE]);
        
        if(auth_data->security.type != IEEE80211_SECURITY_OPEN) {
                assoc_body->capability |= host2uint16_t_le(CAP_SECURITY);
        }
        
        if(auth_data->security.type == IEEE80211_SECURITY_WPA2) {
                memcpy(it, auth_link->rsn_copy, auth_link->rsn_copy_len);
        }
        
        ieee80211_dev->ops->tx_handler(ieee80211_dev, buffer, buffer_size);
        
        /* 
         * Save password and SSID to be used in eventual authentication 
         * handshake. 
         */
        memcpy(ieee80211_dev->bssid_info.password, password, 
                str_size(password));
        
        free(buffer);
        
        return EOK;
}

/** 
 * IEEE 802.11 deauthentication implementation.
 * 
 * @param ieee80211_dev Pointer to IEEE 802.11 device structure.
 * 
 * @return EOK if succeed, negative error code otherwise.
 */
int ieee80211_deauthenticate(ieee80211_dev_t *ieee80211_dev)
{
        ieee80211_scan_result_t *auth_data =
                &ieee80211_dev->bssid_info.res_link->scan_result;
        
        ieee80211_dev->current_auth_phase = IEEE80211_AUTH_DISCONNECTED;
        ieee80211_dev->bssid_info.aid = (uint16_t) -1;
        memcpy(auth_data->bssid.address, ieee80211_broadcast_mac_addr, 
                ETH_ADDR);
        
        nic_t *nic = nic_get_from_ddf_dev(ieee80211_dev->ddf_dev);
        nic_address_t nic_address;
        nic_query_address(nic, &nic_address);
        
        size_t buffer_size = sizeof(ieee80211_mgmt_header_t) + 
                sizeof(ieee80211_deauth_body_t);
        void *buffer = malloc(buffer_size);
        memset(buffer, 0, buffer_size);
        
        ieee80211_mgmt_header_t *mgmt_header = 
                (ieee80211_mgmt_header_t *) buffer;
        
        mgmt_header->frame_ctrl = host2uint16_t_le(
                IEEE80211_MGMT_FRAME | 
                IEEE80211_MGMT_DEAUTH_FRAME
                );
        memcpy(mgmt_header->dest_addr, auth_data->bssid.address, ETH_ADDR);
        memcpy(mgmt_header->src_addr, nic_address.address, ETH_ADDR);
        memcpy(mgmt_header->bssid, auth_data->bssid.address, ETH_ADDR);
        
        ieee80211_dev->ops->tx_handler(ieee80211_dev, buffer, buffer_size);
        
        free(buffer);
        
        ieee80211_dev->ops->bssid_change(ieee80211_dev);
        
        return EOK;
}

static void ieee80211_process_auth_info(ieee80211_scan_result_link_t *ap_data,
        void *buffer)
{
        uint8_t *it = (uint8_t *) buffer;
        
        uint16_t *version = (uint16_t *) it;
        if(uint16_t_le2host(*version) != 0x1) {
                ap_data->scan_result.security.type = -1;
                return;
        }
        
        it += sizeof(uint16_t);
        
        uint32_t group_cipher = *(it+3);
        switch(group_cipher) {
                case IEEE80211_AUTH_CIPHER_TKIP:
                        ap_data->scan_result.security.group_alg =
                                IEEE80211_SECURITY_SUITE_TKIP;
                        break;
                case IEEE80211_AUTH_CIPHER_CCMP:
                        ap_data->scan_result.security.group_alg =
                                IEEE80211_SECURITY_SUITE_CCMP;
                        break;
                default:
                        ap_data->scan_result.security.group_alg = -1;
        }
        
        it += 4*sizeof(uint8_t);
        
        uint16_t *pairwise_count = (uint16_t *) it;
        uint32_t pairwise_cipher = *(it+sizeof(uint16_t)+3);
        switch(pairwise_cipher) {
                case IEEE80211_AUTH_CIPHER_TKIP:
                        ap_data->scan_result.security.pair_alg =
                                IEEE80211_SECURITY_SUITE_TKIP;
                        break;
                case IEEE80211_AUTH_CIPHER_CCMP:
                        ap_data->scan_result.security.pair_alg =
                                IEEE80211_SECURITY_SUITE_CCMP;
                        break;
                default:
                        ap_data->scan_result.security.pair_alg = -1;
        }
        
        it += 2*sizeof(uint16_t) + 
                uint16_t_le2host(*pairwise_count)*sizeof(uint32_t);
        
        uint32_t auth_suite = *(it+3);
        switch(auth_suite) {
                case IEEE80211_AUTH_AKM_PSK:
                        ap_data->scan_result.security.auth =
                                IEEE80211_SECURITY_AUTH_PSK;
                        break;
                case IEEE80211_AUTH_AKM_8021X:
                        ap_data->scan_result.security.auth =
                                IEEE80211_SECURITY_AUTH_8021X;
                        break;
                default:
                        ap_data->scan_result.security.auth = -1;
        }
}

static uint32_t uint32_from_uint8_seq(uint8_t *seq)
{
        return (*seq << 24) + (*(seq+1) << 16) + (*(seq+2) << 8) + *(seq+3); 
}

static uint8_t *ieee80211_process_ies(ieee80211_dev_t *ieee80211_dev,
        ieee80211_scan_result_link_t *ap_data, void *buffer, size_t buffer_size)
{
        void *it = buffer;
        while((it + sizeof(ieee80211_ie_header_t)) < buffer + buffer_size) {
                ieee80211_ie_header_t *ie_header = 
                        (ieee80211_ie_header_t *) it;
                uint8_t *channel;
                switch(ie_header->element_id) {
                        case IEEE80211_CHANNEL_IE:
                                channel = (uint8_t *) 
                                        (it + sizeof(ieee80211_ie_header_t));
                                ap_data->scan_result.channel = *channel;
                                break;
                        case IEEE80211_RSN_IE:
                                if(!ap_data)
                                        break;
                                ap_data->scan_result.security.type =
                                        IEEE80211_SECURITY_WPA2;
                                ieee80211_process_auth_info(ap_data, 
                                        it + sizeof(ieee80211_ie_header_t));
                                ap_data->rsn_copy_len = ie_header->length +
                                        sizeof(ieee80211_ie_header_t);
                                memcpy(ap_data->rsn_copy, 
                                        it, 
                                        ap_data->rsn_copy_len);
                                break;
                        case IEEE80211_VENDOR_IE:
                                if(uint32_from_uint8_seq(it + 
                                        sizeof(ieee80211_ie_header_t)) ==
                                        WPA_OUI) {
                                        if(ap_data->scan_result.security.type ==
                                                IEEE80211_SECURITY_WPA2) {
                                                break;
                                        }
                                        ap_data->scan_result.security.type =
                                                IEEE80211_SECURITY_WPA;
                                        ieee80211_process_auth_info(ap_data,
                                                it + 
                                                sizeof(ieee80211_ie_header_t) +
                                                sizeof(uint32_t));
                                } else if(uint32_from_uint8_seq(it + 
                                        sizeof(ieee80211_ie_header_t)) ==
                                        GTK_OUI) {
                                        return it + 
                                                sizeof(ieee80211_ie_header_t) +
                                                sizeof(uint32_t) + 2;
                                }
                }
                it += sizeof(ieee80211_ie_header_t) + ie_header->length;
        }
        
        return NULL;
}

/**
 * Process probe response and store results.
 * 
 * @param ieee80211_dev Pointer to IEEE 802.11 device structure.
 * @param mgmt_header Pointer to start of management frame header.
 * 
 * @return EOK if succeed, negative error code otherwise.
 */
static int ieee80211_process_probe_response(ieee80211_dev_t *ieee80211_dev, 
        ieee80211_mgmt_header_t *mgmt_header, size_t buffer_size)
{
        ieee80211_beacon_start_t *beacon_body = (ieee80211_beacon_start_t *) 
                ((void *)mgmt_header + sizeof(ieee80211_mgmt_header_t));
        
        ieee80211_ie_header_t *ssid_ie_header = (ieee80211_ie_header_t *) 
                ((void *)beacon_body + sizeof(ieee80211_beacon_start_t));
        
        /* Not empty SSID. */
        if(ssid_ie_header->length > 0) {
                fibril_mutex_t *scan_mutex = &ieee80211_dev->ap_list.scan_mutex;
                
                fibril_mutex_lock(scan_mutex);
                
                ieee80211_scan_result_list_t *result_list =
                        &ieee80211_dev->ap_list;
                
                uint8_t *ssid_start = (uint8_t *) ((void *)ssid_ie_header + 
                        sizeof(ieee80211_ie_header_t));
                char ssid[IEEE80211_MAX_SSID_LENGTH];
                memcpy(ssid, ssid_start, ssid_ie_header->length);
                ssid[ssid_ie_header->length] = '\0';
                
                /* Check whether SSID is already in results. */
                ieee80211_scan_result_list_foreach(*result_list, result) {
                        if(!str_cmp(ssid, result->scan_result.ssid)) {
                                result->last_beacon = time(NULL);
                                fibril_mutex_unlock(scan_mutex);
                                return EOK;
                        }
                }
                
                /* Results are full. */
                if(result_list->size == IEEE80211_MAX_RESULTS_LENGTH - 1) {
                        fibril_mutex_unlock(scan_mutex);
                        return EOK;
                }
                
                ieee80211_scan_result_link_t *ap_data = 
                        malloc(sizeof(ieee80211_scan_result_link_t));
                memset(ap_data, 0, sizeof(ieee80211_scan_result_link_t));
                link_initialize(&ap_data->link);
                
                memcpy(ap_data->scan_result.bssid.address, 
                        mgmt_header->bssid, ETH_ADDR);
                memcpy(ap_data->scan_result.ssid, ssid, 
                        ssid_ie_header->length + 1);
                
                if(uint16_t_le2host(beacon_body->capability) & CAP_SECURITY) {
                        ap_data->scan_result.security.type = 
                                IEEE80211_SECURITY_WEP;
                } else {
                        ap_data->scan_result.security.type = 
                                IEEE80211_SECURITY_OPEN;
                        ap_data->scan_result.security.auth = -1;
                        ap_data->scan_result.security.pair_alg = -1;
                        ap_data->scan_result.security.group_alg = -1;
                }
                
                void *rest_ies_start = ssid_start + ssid_ie_header->length;
                size_t rest_buffer_size = 
                        buffer_size - 
                        sizeof(ieee80211_mgmt_header_t) -
                        sizeof(ieee80211_beacon_start_t) -
                        sizeof(ieee80211_ie_header_t) -
                        ssid_ie_header->length;
                
                ieee80211_process_ies(ieee80211_dev, ap_data, rest_ies_start, 
                        rest_buffer_size);
                
                ap_data->last_beacon = time(NULL);
                
                ieee80211_scan_result_list_append(result_list, ap_data);
                
                fibril_mutex_unlock(scan_mutex);
        }
        
        return EOK;
}

/**
 * Process authentication response.
 * 
 * @param ieee80211_dev Pointer to IEEE 802.11 device structure.
 * @param mgmt_header Pointer to start of management frame header.
 * 
 * @return EOK if succeed, negative error code otherwise.
 */
static int ieee80211_process_auth_response(ieee80211_dev_t *ieee80211_dev,
        ieee80211_mgmt_header_t *mgmt_header)
{
        fibril_mutex_lock(&ieee80211_dev->gen_mutex);
        
        ieee80211_dev->current_auth_phase = IEEE80211_AUTH_AUTHENTICATED;
        
        fibril_condvar_signal(&ieee80211_dev->gen_cond);
        fibril_mutex_unlock(&ieee80211_dev->gen_mutex);
        
        return EOK;
}

/**
 * Process association response.
 * 
 * @param ieee80211_dev Pointer to IEEE 802.11 device structure.
 * @param mgmt_header Pointer to start of management frame header.
 * 
 * @return EOK if succeed, negative error code otherwise.
 */
static int ieee80211_process_assoc_response(ieee80211_dev_t *ieee80211_dev,
        ieee80211_mgmt_header_t *mgmt_header)
{
        ieee80211_scan_result_t *auth_data =
                &ieee80211_dev->bssid_info.res_link->scan_result;
        
        fibril_mutex_lock(&ieee80211_dev->gen_mutex);
        
        ieee80211_assoc_resp_body_t *assoc_resp =
                (ieee80211_assoc_resp_body_t *) ((void *)mgmt_header +
                sizeof(ieee80211_mgmt_header_t));
        
        ieee80211_dev->bssid_info.aid = uint16_t_le2host(assoc_resp->aid);
        memcpy(auth_data->bssid.address, mgmt_header->bssid, ETH_ADDR);
        
        ieee80211_dev->current_auth_phase = IEEE80211_AUTH_ASSOCIATED;
        
        ieee80211_dev->ops->bssid_change(ieee80211_dev);
        
        fibril_condvar_signal(&ieee80211_dev->gen_cond);
        fibril_mutex_unlock(&ieee80211_dev->gen_mutex);
        
        return EOK;
}

static int ieee80211_process_4way_handshake(ieee80211_dev_t *ieee80211_dev,
        void *buffer, size_t buffer_size)
{
        ieee80211_eapol_key_frame_t *key_frame = 
                (ieee80211_eapol_key_frame_t *) buffer;
        
        bool handshake_done = false;
                
        ieee80211_scan_result_link_t *auth_link =
                ieee80211_dev->bssid_info.res_link;

        ieee80211_scan_result_t *auth_data = &auth_link->scan_result;
        uint8_t *ptk = ieee80211_dev->bssid_info.ptk;
        uint8_t *gtk = ieee80211_dev->bssid_info.gtk;

        size_t ptk_key_length, gtk_key_length;
        hash_func_t hash_sel;
        switch(auth_data->security.pair_alg) {
                case IEEE80211_SECURITY_SUITE_CCMP:
                        ptk_key_length = IEEE80211_PTK_CCMP_LENGTH;
                        hash_sel = HASH_SHA1;
                        break;
                default:
                        return ENOTSUP;
        }

        switch(auth_data->security.group_alg) {
                case IEEE80211_SECURITY_SUITE_CCMP:
                        gtk_key_length = IEEE80211_GTK_CCMP_LENGTH;
                        break;
                default:
                        return ENOTSUP;
        }

        size_t output_size = 
                sizeof(eth_header_t) +
                sizeof(ieee80211_eapol_key_frame_t);

        if(!(uint16_t_be2host(key_frame->key_info) & 
                IEEE80211_EAPOL_KEY_KEYINFO_SECURE)) {
                output_size += auth_link->rsn_copy_len;
        }

        nic_t *nic = nic_get_from_ddf_dev(ieee80211_dev->ddf_dev);
        nic_address_t nic_address;
        nic_query_address(nic, &nic_address);

        void *output_buffer = malloc(output_size);
        memset(output_buffer, 0, output_size);

        /* Setup ethernet header. */
        eth_header_t *eth_header = (eth_header_t *) output_buffer;
        memcpy(eth_header->dest_addr, auth_data->bssid.address, ETH_ADDR);
        memcpy(eth_header->src_addr, nic_address.address, ETH_ADDR);
        eth_header->proto = host2uint16_t_be(ETH_TYPE_PAE);

        ieee80211_eapol_key_frame_t *output_key_frame =
                (ieee80211_eapol_key_frame_t *) 
                (output_buffer + sizeof(eth_header_t));

        /* Copy content of incoming EAPOL-Key frame. */
        memcpy((void *) output_key_frame, buffer, 
                sizeof(ieee80211_eapol_key_frame_t));

        output_key_frame->proto_version = 0x1;
        output_key_frame->key_length = 0;
        output_key_frame->body_length =
                host2uint16_t_be(output_size - sizeof(eth_header_t)-4);
        output_key_frame->key_info &= 
                ~host2uint16_t_be(
                        IEEE80211_EAPOL_KEY_KEYINFO_ACK
                );

        /* 
         * Check if it is last or first incoming message in 4-way 
         * handshake. 
         */
        if(uint16_t_be2host(key_frame->key_info) & 
                IEEE80211_EAPOL_KEY_KEYINFO_SECURE) {
                output_key_frame->key_info &= 
                        ~host2uint16_t_be(
                                IEEE80211_EAPOL_KEY_KEYINFO_ENCDATA
                        );
                output_key_frame->key_info &= 
                        ~host2uint16_t_be(
                                IEEE80211_EAPOL_KEY_KEYINFO_INSTALL
                        );
                output_key_frame->key_data_length = 0;
                output_key_frame->key_length = 0;
                memset(output_key_frame->key_nonce, 0, 32);
                memset(output_key_frame->key_mic, 0, 16);
                memset(output_key_frame->key_rsc, 0, 8);
                memset(output_key_frame->eapol_key_iv, 0, 16);

                /* Derive GTK and save it. */
                uint16_t key_data_length = 
                        uint16_t_be2host(key_frame->key_data_length);
                uint16_t decrypt_len = key_data_length - 8;
                uint8_t key_data[decrypt_len];
                uint8_t *data_ptr = (uint8_t *) (buffer + 
                        sizeof(ieee80211_eapol_key_frame_t));
                if(ieee80211_aes_key_unwrap(ptk + KEK_OFFSET, data_ptr,
                        key_data_length, key_data) == EOK) {
                        
                        uint8_t *key_ptr = ieee80211_process_ies(ieee80211_dev, 
                                NULL, key_data, decrypt_len);

                        if(key_ptr) {
                                memcpy(gtk, key_ptr, gtk_key_length);
                                handshake_done = true;
                        }
                }
        } else {
                output_key_frame->key_info |= 
                        host2uint16_t_be(
                                IEEE80211_EAPOL_KEY_KEYINFO_MIC
                        );
                output_key_frame->key_data_length =
                        host2uint16_t_be(auth_link->rsn_copy_len);
                memcpy((void *)output_key_frame + 
                        sizeof(ieee80211_eapol_key_frame_t),
                        auth_link->rsn_copy,
                        auth_link->rsn_copy_len);

                /* Compute PMK. */
                uint8_t pmk[PBKDF2_KEY_LENGTH];
                pbkdf2((uint8_t *) ieee80211_dev->bssid_info.password,
                        str_size(ieee80211_dev->bssid_info.password),
                        (uint8_t *) auth_data->ssid,
                        str_size(auth_data->ssid), pmk, hash_sel);

                uint8_t *anonce = key_frame->key_nonce;

                /* Generate SNONCE. */
                uint8_t snonce[32];
                rnd_sequence(snonce, 32);

                memcpy(output_key_frame->key_nonce, snonce, 32);

                uint8_t *dest_addr = eth_header->dest_addr;
                uint8_t *src_addr = eth_header->src_addr;

                /* Derive PTK and save it. */
                uint8_t prf_result[ptk_key_length];
                uint8_t crypt_data[PRF_CRYPT_DATA_LENGTH];
                memcpy(crypt_data, 
                        min_sequence(dest_addr, src_addr, ETH_ADDR), 
                        ETH_ADDR);
                memcpy(crypt_data + ETH_ADDR, 
                        max_sequence(dest_addr, src_addr, ETH_ADDR), 
                        ETH_ADDR);
                memcpy(crypt_data + 2*ETH_ADDR, 
                        min_sequence(anonce, snonce, 32), 
                        32);
                memcpy(crypt_data + 2*ETH_ADDR + 32, 
                        max_sequence(anonce, snonce, 32),
                        32);
                ieee80211_prf(pmk, crypt_data, prf_result, hash_sel);
                memcpy(ptk, prf_result, ptk_key_length);
        }

        /* Compute MIC of key frame data from KCK part of PTK. */
        uint8_t mic[SHA1_HASH_LENGTH];
        hmac(ptk, 16, (uint8_t *) output_key_frame, 
                output_size - sizeof(eth_header_t), mic, hash_sel);

        memcpy(output_key_frame->key_mic, mic, 16);

        ieee80211_send_frame(nic, output_buffer, output_size);

        free(output_buffer);

        if(handshake_done) {
                /* Insert keys into device. */
                
                /* Pairwise key. */
                ieee80211_key_config_t key_config;
                key_config.suite = auth_data->security.pair_alg;
                key_config.flags =
                        IEEE80211_KEY_FLAG_TYPE_PAIRWISE;
                memcpy(key_config.data, 
                        ptk + TK_OFFSET,
                        ptk_key_length - TK_OFFSET);

                ieee80211_dev->ops->key_config(ieee80211_dev,
                        &key_config, true);
                
                /* Group key. */
                key_config.suite = auth_data->security.group_alg;
                key_config.flags =
                        IEEE80211_KEY_FLAG_TYPE_GROUP;
                memcpy(key_config.data, gtk, gtk_key_length);

                ieee80211_dev->ops->key_config(ieee80211_dev,
                        &key_config, true);

                /* Signal successful handshake completion. */
                fibril_mutex_lock(&ieee80211_dev->gen_mutex);
                fibril_condvar_signal(&ieee80211_dev->gen_cond);
                fibril_mutex_unlock(&ieee80211_dev->gen_mutex);
        }
        
        return EOK;
}

static int ieee80211_process_eapol_frame(ieee80211_dev_t *ieee80211_dev,
        void *buffer, size_t buffer_size)
{
        ieee80211_eapol_key_frame_t *key_frame = 
                (ieee80211_eapol_key_frame_t *) buffer;
        if(ieee80211_is_eapol_key_frame(key_frame)) {
                return ieee80211_process_4way_handshake(ieee80211_dev, buffer,
                        buffer_size);
        }
        
        return EOK;
}

/**
 * Process data frame.
 * 
 * @param ieee80211_dev Pointer to IEEE 802.11 device structure.
 * @param buffer Data buffer starting with IEEE 802.11 data header.
 * @param buffer_size Size of buffer.
 * 
 * @return EOK if succeed, negative error code otherwise.
 */
static int ieee80211_process_data(ieee80211_dev_t *ieee80211_dev, 
        void *buffer, size_t buffer_size)
{
        ieee80211_data_header_t *data_header = 
                (ieee80211_data_header_t *) buffer;
        
        if(ieee80211_has_data_frame(data_header->frame_ctrl)) {
                nic_t *nic = nic_get_from_ddf_dev(ieee80211_dev->ddf_dev);
                size_t strip_length = sizeof(ieee80211_data_header_t) + 
                        ARRAY_SIZE(rfc1042_header);
                
                /* TODO: Probably different by used security alg. */
                if(ieee80211_is_encrypted_frame(data_header->frame_ctrl)) {
                        strip_length += 8;
                }
                
                /* Process 4-way authentication handshake. */
                uint16_t *proto = (uint16_t *) (buffer + strip_length);
                if(uint16_t_be2host(*proto) == ETH_TYPE_PAE) {
                        return ieee80211_process_eapol_frame(ieee80211_dev,
                                buffer + strip_length + sizeof(uint16_t),
                                buffer_size - strip_length - sizeof(uint16_t));
                }
                
                /* Note: ETH protocol ID is already there, so we don't create 
                 * whole ETH header. */
                size_t frame_size = 
                        buffer_size - strip_length + sizeof(eth_header_t)-2;
                nic_frame_t *frame = nic_alloc_frame(nic, frame_size);

                if(frame == NULL) {
                        return ENOMEM;
                }

                uint8_t *src_addr = 
                        ieee80211_is_fromds_frame(data_header->frame_ctrl) ?
                                data_header->address3 : data_header->address2;
                uint8_t *dest_addr = 
                        ieee80211_is_tods_frame(data_header->frame_ctrl) ?
                                data_header->address3 : data_header->address1;

                eth_header_t *eth_header =
                        (eth_header_t *) frame->data;
                memcpy(eth_header->src_addr, src_addr, ETH_ADDR);
                memcpy(eth_header->dest_addr, dest_addr, ETH_ADDR);

                memcpy(frame->data + sizeof(eth_header_t)-2, 
                        buffer + strip_length, 
                        buffer_size - strip_length);

                nic_received_frame(nic, frame);
        }
        
        return EOK;
}

/**
 * IEEE 802.11 RX frames handler.
 * 
 * @param ieee80211_dev Pointer to IEEE 802.11 device structure.
 * @param buffer Buffer with data.
 * @param buffer_size Size of buffer.
 * 
 * @return EOK if succeed, negative error code otherwise.
 */
int ieee80211_rx_handler(ieee80211_dev_t *ieee80211_dev, void *buffer,
        size_t buffer_size)
{
        uint16_t frame_ctrl = *((uint16_t *) buffer);
        if(ieee80211_is_mgmt_frame(frame_ctrl)) {
                ieee80211_mgmt_header_t *mgmt_header =
                        (ieee80211_mgmt_header_t *) buffer;
                
                if(ieee80211_is_probe_response_frame(mgmt_header->frame_ctrl) ||
                        ieee80211_is_beacon_frame(mgmt_header->frame_ctrl)) {
                        return ieee80211_process_probe_response(ieee80211_dev,
                                mgmt_header, buffer_size);
                }
                
                if(ieee80211_is_auth_frame(mgmt_header->frame_ctrl)) {
                        return ieee80211_process_auth_response(ieee80211_dev,
                                mgmt_header);
                }
                
                if(ieee80211_is_assoc_response_frame(mgmt_header->frame_ctrl)) {
                        return ieee80211_process_assoc_response(ieee80211_dev,
                                mgmt_header);
                }
        } else if(ieee80211_is_data_frame(frame_ctrl)) {
                return ieee80211_process_data(ieee80211_dev, buffer, 
                        buffer_size);
        }
        
        return EOK;
}

/** @}
 */