source: ReferenceDesigns/w3_802.11/c/wlan_mac_high_ap/wlan_mac_ap.c

/** @file wlan_mac_ap.c
 *  @brief Access Point
 *
 *  This contains code for the 802.11 Access Point.
 *
 *  @copyright Copyright 2013-2019, Mango Communications. All rights reserved.
 *          Distributed under the Mango Communications Reference Design License
 *              See LICENSE.txt included in the design archive or
 *              at http://mangocomm.com/802.11/license
 *
 *  This file is part of the Mango 802.11 Reference Design (https://mangocomm.com/802.11)
 */

// Xilinx SDK includes
#include "stdlib.h"
#include "string.h"
#include "xil_cache.h"
// 802.11 ref design headers
#include "wlan_mac_high_sw_config.h"
#include "wlan_mac_common.h"
#include "wlan_platform_common.h"
#include "wlan_platform_high.h"

#include "wlan_mac_high.h"
#include "wlan_mac_ap.h"
#include "wlan_mac_addr_filter.h"
#include "wlan_mac_ltg.h"
#include "wlan_mac_event_log.h"
#include "wlan_mac_schedule.h"
#include "wlan_mac_queue.h"
#include "wlan_mac_802_11_defs.h"
#include "wlan_mac_packet_types.h"
#include "wlan_mac_network_info.h"
#include "wlan_mac_station_info.h"
#include "wlan_mac_mgmt_tags.h"
#include "wlan_mac_eth_util.h"
#include "wlan_mac_scan.h"
#include "wlan_mac_pkt_buf_util.h"
#include "wlan_mac_entries.h"
#include "wlan_mac_dl_list.h"

#include "wlan_exp.h"
#include "wlan_exp_node.h"
#include "wlan_exp_node_ap.h"
#include "wlan_exp_transport.h"


/*************************** Constant Definitions ****************************/

#define WLAN_DEFAULT_BSS_CONFIG_CHANNEL 1
#define WLAN_DEFAULT_BSS_CONFIG_DTIM_PERIOD 2
#define WLAN_DEFAULT_BSS_CONFIG_BEACON_INTERVAL 100
// The WLAN_DEFAULT_BSS_CONFIG_HT_CAPABLE define will set the default
// unicast TX phy mode to:  1 --> HTMF  or  0 --> NONHT.
#define WLAN_DEFAULT_BSS_CONFIG_HT_CAPABLE 1

#define WLAN_DEFAULT_TX_PWR 15
#define WLAN_DEFAULT_TX_ANTENNA TX_ANTMODE_SISO_ANTA
#define WLAN_DEFAULT_RX_ANTENNA RX_ANTMODE_SISO_ANTA


/*********************** Global Variable Definitions *************************/


/*************************** Variable Definitions ****************************/

// SSID variables
static char default_AP_SSID[] = "MANGO-AP";

// "active_network_info" is a pointer to the network_info that describes this AP.
// Inside this structure is a dl_list of members. This is a list
// of all stations that are currently associated with this AP. In the
// 802.11-2012 Section 10.3 parlance, these stations are currently
// in State 4 (Authenticated, Associated). As part of the association
// process, we want to track stations as they transition through the
// 10.3 states. To do this, we'll create a totally separate dl_list of
// station_info that represent stations in State 2
// (Authenticated, Unassociated). Only members of this list will be allowed
// to elevate to State 4 in the active_bss_info.
network_info_t* active_network_info;

dl_list authenticated_unassociated_stations;

// Tx queue variables;
u32 max_queue_size;
volatile u8 pause_data_queue;

// MAC address
static u8 wlan_mac_addr[MAC_ADDR_LEN];

// Traffic Indication Map (TIM) State
// These global structs must be protected against externing. Any
// modifications of these structs should be done via an explicit
// setter that also updates the beacon template.
static volatile mgmt_tag_template_t* mgmt_tag_tim_template;
static volatile u32 mgmt_tag_tim_update_schedule_id;

// Beacon configuration
static beacon_txrx_config_t gl_beacon_txrx_config;

// Static QIDs
u16 mcast_qid;
u16 mgmt_qid;

// DTIM Multicast Buffer
u8 gl_dtim_mcast_buffer_enable; // Enable buffering of multicast packets until after DTIM transmission
u8 gl_cpu_low_supports_dtim_mcast; // Flag to indicate if DTIM multicast buffering is supported by the low-level MAC

// Common Platform Device Info
platform_common_dev_info_t platform_common_dev_info;

/*************************** Functions Prototypes ****************************/

#if WLAN_SW_CONFIG_ENABLE_WLAN_EXP
int  wlan_exp_process_user_cmd(cmd_resp_hdr_t* cmd_hdr, eth_tx_queue_buffer_t* eth_tx_queue_buffer);
#endif


/******************************** Functions **********************************/

int main(){

    // Call the platform-supplied cpu_init() first to setup any
    //  processor-specific settings to enable sane execution
    //  of the platform and framework code below
    wlan_platform_cpu_high_init();

    u32              update_mask;
    bss_config_t     bss_config;

    xil_printf("\f");
    xil_printf("----- Mango 802.11 Reference Design -----\n");
    xil_printf("----- v1.8.0 ----------------------------\n");
    xil_printf("----- wlan_mac_ap -----------------------\n");

    xil_printf("Compiled %s %s\n\n", __DATE__, __TIME__);

    // Heap Initialization
    //    The heap must be initialized before any use of malloc. This explicit
    //    init handles the case of soft-reset of the MicroBlaze leaving stale
    //    values in the heap RAM
    wlan_mac_common_malloc_init();

    //Initialize the MAC framework
    wlan_mac_high_init();

    // Get the device info
    platform_common_dev_info = wlan_platform_common_get_dev_info();

    // Before any queue entries are used, calculate the maximum number of
    // allowed enqueues based on the number that are free
    max_queue_size = WLAN_MIN( queue_num_free(), MAX_TX_QUEUE_LEN );

    // Open static queues for multicast and management frames
    //  We will use a single queue for all multicast frames. The occupancy of this
    //   queue will be reflecting in the TIM tag in beacons, so we must attach a
    //   function callback to be notified when the queue changes
    mcast_qid = queue_open((void*)queue_state_change, 0, max_queue_size);

    //  We will use a queue for unicast management frames that are not addressed
    //   to associated stations (e.g. a unicast probe response to a station
    //   performing an active scan). Because there is no AID fo an unassociated
    //   station, we do not need to be notified of occupancy changes for this
    //   queue. So, we will attach the default null callback in the framework.
    mgmt_qid  = queue_open((void*)wlan_null_callback, 0, max_queue_size);

    pause_data_queue = 0;

    gl_cpu_low_supports_dtim_mcast = 0;

    //Set a sane default for the TIM tag byte offset
    gl_beacon_txrx_config.dtim_tag_byte_offset = 0;

    // AP does not currently advertise a BSS
    configure_bss(NULL, 0);

    // Initialize hex display to "No BSS"
    wlan_platform_high_userio_disp_status(USERIO_DISP_STATUS_MEMBER_LIST_UPDATE, 0xFF);

    // Set default Tx params
    // Set sane default Tx params. These will be overwritten by the user application
    tx_params_t tx_params = { .phy = { .mcs = 3, .phy_mode = PHY_MODE_HTMF, .antenna_mode = WLAN_DEFAULT_TX_ANTENNA, .power = WLAN_DEFAULT_TX_PWR },
                              .mac = { .flags = 0 } };

    wlan_mac_set_default_tx_params(unicast_data, &tx_params);

    tx_params.phy.mcs = 0;
    tx_params.phy.phy_mode = PHY_MODE_NONHT;

    wlan_mac_set_default_tx_params(unicast_mgmt, &tx_params);
    wlan_mac_set_default_tx_params(mcast_data, &tx_params);
    wlan_mac_set_default_tx_params(mcast_mgmt, &tx_params);

    // Re-apply the defaults to any existing station_info_t structs that this AP
    // knows about
    wlan_mac_reapply_default_tx_params();

    // Initialize callbacks
#if WLAN_SW_CONFIG_ENABLE_ETH_BRIDGE
    wlan_mac_util_set_eth_rx_callback((void*)ethernet_receive);
#endif
    wlan_mac_high_set_mpdu_rx_callback((void*)mpdu_rx_process);
    wlan_mac_high_set_press_pb_0_callback((void*)button_0_press);
    wlan_mac_high_set_release_pb_0_callback((void*)button_0_release);
    wlan_mac_high_set_uart_rx_callback((void*)uart_rx);
    wlan_mac_high_set_poll_tx_queues_callback((void*)poll_tx_queues);
    wlan_mac_high_set_mpdu_dequeue_callback((void*)mpdu_dequeue);
#if WLAN_SW_CONFIG_ENABLE_LTG
    wlan_mac_ltg_sched_set_callback((void*)ltg_event);
#endif //WLAN_SW_CONFIG_ENABLE_LTG
    wlan_mac_scan_set_state_change_callback((void*)process_scan_state_change);
    wlan_mac_high_set_cpu_low_reboot_callback((void*)handle_cpu_low_reboot);
    wlan_mac_high_set_tx_queue_state_change_callback((void*)queue_state_change);

#if WLAN_SW_CONFIG_ENABLE_WLAN_EXP

    // NOTE:  To use the WLAN Experiments Framework, it must be initialized after
    //        CPU low has populated the hw_info structure in the MAC High framework.

    // Initialize WLAN Exp
    wlan_exp_node_init();

    // Set WLAN Exp callbacks
    wlan_exp_set_process_node_cmd_callback((void *) process_wlan_exp_app_cmd);
    wlan_exp_set_purge_all_wireless_tx_queue_callback((void *) purge_all_wireless_tx_queue);
    wlan_exp_set_process_user_cmd_callback((void *) wlan_exp_process_user_cmd);
    //   - wlan_exp_set_beacon_ts_update_mode_callback()  currently not supported by the AP
    wlan_exp_set_process_config_bss_callback((void *) configure_bss);
    wlan_exp_set_active_network_info_getter_callback((void *) active_network_info_getter);

    // Set CPU_HIGH Type in wlan_exp's node_info struct;
    wlan_exp_node_set_type_high(APPLICATION_ROLE_AP, __DATE__, __TIME__);

#endif

    memcpy((void*) &(wlan_mac_addr[0]), (void*) get_mac_hw_addr_wlan(), MAC_ADDR_LEN);

    // Set the at-boot MAC Time to 0 usec
    set_mac_time_usec(0);

    wlan_mac_high_set_radio_channel(WLAN_DEFAULT_BSS_CONFIG_CHANNEL);
    wlan_mac_high_set_rx_ant_mode(WLAN_DEFAULT_RX_ANTENNA);
    wlan_mac_high_set_tx_ctrl_power(WLAN_DEFAULT_TX_PWR);
    wlan_mac_high_set_radio_tx_power(WLAN_DEFAULT_TX_PWR);

    // Initialize TIM management tag that will be postpended to a beacon
    mgmt_tag_tim_update_schedule_id = SCHEDULE_ID_RESERVED_MAX;
    mgmt_tag_tim_template = NULL;

    //  Periodic check for timed-out associations
    wlan_mac_schedule_add_event(SCHEDULE_ID_COARSE, ASSOCIATION_CHECK_INTERVAL_US, SCHEDULE_REPEAT_FOREVER, (void*)remove_inactive_station_infos);

    wlan_platform_high_userio_disp_status(USERIO_DISP_STATUS_APPLICATION_ROLE, APPLICATION_ROLE_AP);

#if WLAN_SW_CONFIG_ENABLE_LOGGING
    // Reset the event log
    event_log_reset();
#endif //WLAN_SW_CONFIG_ENABLE_LOGGING

    // If the DIP switch allows it, set up BSS description
    if ((wlan_platform_userio_get_state() & USERIO_INPUT_MASK_SW_3) == 0) {
        memcpy(bss_config.bssid, wlan_mac_addr, MAC_ADDR_LEN);
        strncpy(bss_config.ssid, default_AP_SSID, SSID_LEN_MAX);

        bss_config.chan_spec.chan_pri  = WLAN_DEFAULT_BSS_CONFIG_CHANNEL;
        bss_config.chan_spec.chan_type = CHAN_TYPE_BW20;
        bss_config.ht_capable          = WLAN_DEFAULT_BSS_CONFIG_HT_CAPABLE;
        bss_config.beacon_interval     = WLAN_DEFAULT_BSS_CONFIG_BEACON_INTERVAL;
        bss_config.dtim_period         = WLAN_DEFAULT_BSS_CONFIG_DTIM_PERIOD;

        update_mask = (BSS_FIELD_MASK_BSSID              |
                       BSS_FIELD_MASK_CHAN               |
                       BSS_FIELD_MASK_SSID               |
                       BSS_FIELD_MASK_BEACON_INTERVAL    |
                       BSS_FIELD_MASK_HT_CAPABLE         |
                       BSS_FIELD_MASK_DTIM_PERIOD);
        configure_bss(&bss_config, update_mask);
    }

    gl_dtim_mcast_buffer_enable = 1;
    wlan_mac_high_enable_mcast_buffering(gl_dtim_mcast_buffer_enable);

    // Print AP information to the terminal

    xil_printf("------------------------\n");
    xil_printf("WLAN MAC AP boot complete\n");

#ifdef WLAN_USE_UART_MENU
    xil_printf("\nPress the Esc key in your terminal to access the UART menu\n");
#endif

    // Finally enable all interrupts to start handling wireless and wired traffic
    wlan_platform_intc_set_state(INTERRUPTS_ENABLED);

    while(1) {
        wlan_mac_poll();
    }

    // Unreachable, but non-void return keeps the compiler happy
    return WLAN_FAILURE;
}


/*****************************************************************************/
/**
 * @brief Handle state change in the network scanner
 *
 * This function is part of the scan infrastructure and will be called whenever
 * the scanner is started, stopped, paused, or resumed. This allows the STA
 * to revert the channel to a known-good state when the scanner has stopped and
 * also serves as notification to the project that it should stop dequeueing data
 * frames since it might be on a different channel than its intended recipient.
 *
 * @param   None
 * @return  None
 *
 *****************************************************************************/
void process_scan_state_change(scan_state_t scan_state){

    // ------------------------------------------------------------------------
    // Note on scanning:
    //
    //   Currently, scanning should only be done with active_bss_info = NULL, ie the
    // node is not currently in a BSS.  This is to avoid any corner cases.  The
    // AP needs to do the following things to make scanning safe when active_bss_info
    // is not NULL:
    //
    //     - Pause outgoing data queues
    //     - Pause beacon transmissions in CPU_LOW
    //     - Refuse to enqueue probe responses when a probe request is received off channel
    //     - Pause dequeue of probe responses when off channel
    //       - Note: Currently, this is difficult because probe responses share a
    //             queue with probe requests which are needed for active scans
    //
    // ------------------------------------------------------------------------

    switch(scan_state){
        case SCAN_IDLE:
        case SCAN_PAUSED:
            pause_data_queue = 0;
            if(active_network_info != NULL){
                wlan_mac_high_set_radio_channel(
                        wlan_mac_high_bss_channel_spec_to_radio_chan(active_network_info->bss_config.chan_spec));
            }
        break;
        case SCAN_RUNNING:
            pause_data_queue = 1;
        break;
    }
}

/*****************************************************************************/
/**
 * @brief Handle queue occupancy change
 *
 * Beacons must contain a TIM tag that dedicates one bit per associated station
 * that indicates whether any downlink traffic is enqueued for that station.
 * This allows stations to save power by dozing during beacon intervals and wake
 * up only when they know downlink traffic is ready for them
 *
 * This function can be attached to a queue so that is called whenever the queue
 * transitions from empty to 1 packet or vice versa.
 *
 * @param   u32 aid - the framework will call this function with the callback
 *                    argument provided during queue_open(). This application
 *                    chooses to let that argument be the AID for that queue
 * @param   u32 queue_len - 0 if the queue is now empty, 1 if the queue now has
 *                          a single entry
 * @return  None
 *****************************************************************************/
void queue_state_change(u32 aid, u32 queue_len){
    //queue_len will take on a value of 0 or 1
    //and represents the state of the queue after the state
    //changes.

    if(mgmt_tag_tim_update_schedule_id != SCHEDULE_ID_RESERVED_MAX){
        //We already have a pending full TIM state re-write scheduled, so we won't bother
        //with a per-queue change.
        return;
    }

    if(mgmt_tag_tim_template == NULL){
        //The TIM tag is not present in the current beacon template.
        //We have no choice but to do a full TIM tag update and write.
        update_tim_tag_all(SCHEDULE_ID_RESERVED_MAX);
    } else {
        //There is a TIM tag that is already present. We can update
        //only the relevant byte that applies to this queue state
        //change
        update_tim_tag_aid(aid, queue_len);
    }
}



/*****************************************************************************/
/**
 *
 *****************************************************************************/
inline void update_tim_tag_aid(u8 aid, u8 bit_val_in){

    // The intention of this function is to modify as little of an existing TIM
    // tag in the beacon template packet buffer as possible to reduce the amount
    // of time that CPU could be waiting on the packet buffer to be unlocked.
    //
    //Note: AID = 0 is invalid. And input of 0 to this function
    //indicates that the multicast bit in the tim_control byte should
    //be modified if DTIM mcast buffering is currently disabled. Otherwise,
    //CPU_LOW will maintain this bit.

    u32 existing_mgmt_tag_length = 0; // Size of the management tag that is currently in the packet buffer
    u8 tim_control = 0;
    u16 tim_byte_idx = 0;
    u8 tim_bit_idx = 0;
    u8 bit_val = (bit_val_in & 1);
    tx_frame_info_t* tx_frame_info = (tx_frame_info_t*)CALC_PKT_BUF_ADDR(platform_common_dev_info.tx_pkt_buf_baseaddr, TX_PKT_BUF_BEACON);

    if(active_network_info == NULL) return;
    if( ((aid==0) && (gl_dtim_mcast_buffer_enable == 1)) ) return;

    //First, we should determine whether a call to update_tim_tag_all_tag_all is scheduled
    //for some time in the future. If it is, we can just return immediately and let that
    //execution clean up any pending TIM state changes.
    if(mgmt_tag_tim_update_schedule_id != SCHEDULE_ID_RESERVED_MAX){
        return;
    }

    if(mgmt_tag_tim_template == NULL){
        //There currently isn't any TIM tag in the packet buffer, which means
        //that we need to restore the full state and not toggle a single
        //bit
        update_tim_tag_all(SCHEDULE_ID_RESERVED_MAX);
        return;
    }

    //There exists a TIM tag in the beacon. We should determine its length
    existing_mgmt_tag_length    = mgmt_tag_tim_template->header.tag_length;
    tim_byte_idx                = aid / 8;

    if((tim_byte_idx + 4U) > existing_mgmt_tag_length){
        //The current byte we intend to modify is larger than the existing tag. In this case,
        //we fall back on the update_tim_tag_all function since we cannnot simply modify a single
        //bit.
        update_tim_tag_all(SCHEDULE_ID_RESERVED_MAX);
        return;
    }

    if( ((tx_frame_info->tx_pkt_buf_state != TX_PKT_BUF_READY) && (tx_frame_info->tx_pkt_buf_state != TX_PKT_BUF_HIGH_CTRL) ) || (lock_tx_pkt_buf(TX_PKT_BUF_BEACON) != PKT_BUF_MUTEX_SUCCESS)){
        //Note: The order of operations in the above if() clause is important. If the tx_pkt_buf_state is not ready.
        //then we should not even attempt to lock the beacon template packet buffer. This behavior is ensured if
        //the tx_pkt_buf_state is checked on on the left-hand side of the || because the || operation is a sequence
        //point in C.

        //CPU_LOW currently has the beacon packet buffer locked, which means that it is actively
        //transmitting the beacon and it is not safe to modify the contents of the packet. We will
        //use the scheduler to call update_tim_tag_all() sometime later when it is likely that the
        //packet buffer is no longer locked.
        mgmt_tag_tim_update_schedule_id = wlan_mac_schedule_add_event(SCHEDULE_ID_FINE,
                                                                           (active_network_info->bss_config.beacon_interval * BSS_MICROSECONDS_IN_A_TU) / 4,
                                                                           1,
                                                                           (void*)update_tim_tag_all);
        return;
    }

    // If we have made it this far into the function, then we know that the TIM tag currently
    // exists in the beacon template packet buffer, the mgmt_tag_tim_template is non-NULL, and
    // finally that the TIM tag is long enough that we can simply modify bit(s) that correspond
    // to the AID argument of the function.

    if(aid == 0){
        if(bit_val){
            tim_control |= 0x01; //Raise the multicast bit in the TIM control field
            mgmt_tag_tim_template->data[2] = tim_control;           //TIM Control (top 7 bits are offset for partial map)
            mgmt_tag_tim_template->data[3] |= tim_control&1;        //Per 10.2.1.3 in 802.11-2012: AID 0 is treated as
                                                                    //the multicast buffer state
        } else {
            tim_control = 0;
            mgmt_tag_tim_template->data[2] = tim_control;           //TIM Control (top 7 bits are offset for partial map)
            mgmt_tag_tim_template->data[3] &= ~(tim_control&1);     //Per 10.2.1.3 in 802.11-2012: AID 0 is treated as
                                                                    //the multicast buffer state
        }
    } else {
        if(bit_val){
            mgmt_tag_tim_template->data[3+tim_byte_idx] |= 1<<tim_bit_idx;
        } else {
            mgmt_tag_tim_template->data[3+tim_byte_idx] &= ~(1<<tim_bit_idx);
        }
    }

    if(unlock_tx_pkt_buf(TX_PKT_BUF_BEACON) != PKT_BUF_MUTEX_SUCCESS){
        xil_printf("Error: Unable to unlock Beacon packet buffer during update_tim_tag_all\n");
    }
    return;

}



/*****************************************************************************/
/**
 *
 *****************************************************************************/
void update_tim_tag_all(u32 sched_id){

    tx_frame_info_t* tx_frame_info = (tx_frame_info_t*)CALC_PKT_BUF_ADDR(platform_common_dev_info.tx_pkt_buf_baseaddr, TX_PKT_BUF_BEACON);
    u32 existing_mgmt_tag_length = 0; // Size of the management tag that is currently in the packet buffer
    u32 next_mgmt_tag_length = 0; // Size that we will update the management tag to be.
                                                            // Note: a third size we have to track is present in the global mgmt_tag_tim
    station_info_entry_t* curr_station_entry;
    station_info_t* station_info;
    u8 tim_control;
    u32 i;
    u16 tim_byte_idx = 0;
    u16 tim_next_byte_idx = 0;
    u8 tim_bit_idx = 0;

    if(active_network_info == NULL) return;
    if(sched_id == SCHEDULE_ID_RESERVED_MAX){
        //This function was called manually (not via the scheduler)

        //First, we should determine whether a call to update_tim_tag_all is scheduled
        //for some time in the future. If it is, we can just return immediately and let that
        //execution clean up any pending TIM state changes.
        if(mgmt_tag_tim_update_schedule_id != SCHEDULE_ID_RESERVED_MAX){
            return;
        }
    }

    mgmt_tag_tim_update_schedule_id = SCHEDULE_ID_RESERVED_MAX;

    if( ((tx_frame_info->tx_pkt_buf_state != TX_PKT_BUF_READY) && (tx_frame_info->tx_pkt_buf_state != TX_PKT_BUF_HIGH_CTRL) ) || (lock_tx_pkt_buf(TX_PKT_BUF_BEACON) != PKT_BUF_MUTEX_SUCCESS)){
        //Note: The order of operations in the above if() clause is important. If the tx_pkt_buf_state is not ready.
        //then we should not even attempt to lock the beacon template packet buffer. This behavior is ensured if
        //the tx_pkt_buf_state is checked on on the left-hand side of the || because the || operation is a sequence
        //point in C.

        //CPU_LOW currently has the beacon packet buffer locked, which means that it is actively
        //transmitting the beacon and it is not safe to modify the contents of the packet. We will
        //use the scheduler to call update_tim_tag_all() sometime later when it is likely that the
        //packet buffer is no longer locked.
        mgmt_tag_tim_update_schedule_id = wlan_mac_schedule_add_event(SCHEDULE_ID_FINE,
                                                                           (active_network_info->bss_config.beacon_interval * BSS_MICROSECONDS_IN_A_TU) / 4,
                                                                           1,
                                                                           (void*)update_tim_tag_all);
        return;
    }

    if(mgmt_tag_tim_template != NULL){
        //There exists a TIM tag in the beacon. We should determine its length
        existing_mgmt_tag_length = mgmt_tag_tim_template->header.tag_length;
    }

    //----------------------------------
    // 1. We will refresh the full state of the TIM tag based upon queue occupancy

    //We'll start updating the TIM tag from the last associated station.
    //Since we know that the WLAN MAC High Framework keeps the dl_list of
    //associated stations in increasing AID order, we can use this final
    //station's AID to define the size of the TIM tag.
    curr_station_entry = (station_info_entry_t*)(active_network_info->members.last);

    if(curr_station_entry != NULL){
        station_info = (station_info_t*)(curr_station_entry->data);
        next_mgmt_tag_length = 4 + ((station_info->ID) / 8);
    } else {
        next_mgmt_tag_length = 4;
    }

    if(mgmt_tag_tim_template == NULL){
        //We need to add the tag to the end of the beacon template
        //and update the length field of the tx_frame_info.
        mgmt_tag_tim_template = (mgmt_tag_template_t*)((void*)(tx_frame_info)
                                                +PHY_TX_PKT_BUF_MPDU_OFFSET
                                                +tx_frame_info->length
                                                -WLAN_PHY_FCS_NBYTES);
        gl_beacon_txrx_config.dtim_tag_byte_offset = (u16)((u32)mgmt_tag_tim_template - (u32)tx_frame_info);

        mgmt_tag_tim_template->header.tag_element_id    = MGMT_TAG_TIM;
        tx_frame_info->length += sizeof(mgmt_tag_header);
    }

    mgmt_tag_tim_template->header.tag_length        = next_mgmt_tag_length;

    tim_control = 0; //The top 7 bits are an offset for the partial map

    if((gl_dtim_mcast_buffer_enable == 0) && (queue_length(mcast_qid)>0)){
        //If mcast buffering is disabled, the AP is responsible for maintaining the
        //mcast bit in the TIM control
        tim_control |= 0x01; //Raise the multicast bit in the TIM control field
    }

    curr_station_entry = (station_info_entry_t*)(active_network_info->members.first);
    while(curr_station_entry != NULL){
        station_info = (station_info_t*)(curr_station_entry->data);

        if(queue_length(station_info->QID)){
            tim_next_byte_idx = (station_info->ID) / 8;

            if(tim_next_byte_idx > tim_byte_idx){
                //We've moved on to a new octet. We should zero everything after the previous octet
                //up to and including the new octet.
                for(i = tim_byte_idx+1; i <= tim_next_byte_idx; i++){
                    mgmt_tag_tim_template->data[3+i] = 0;
                }
            }

            tim_bit_idx  = (station_info->ID) % 8;
            tim_byte_idx = tim_next_byte_idx;

            //Raise the bit for this station in the TIM partial bitmap
            mgmt_tag_tim_template->data[3+tim_byte_idx] |= 1<<tim_bit_idx;
        }

        curr_station_entry = dl_entry_next(curr_station_entry);
    }

    //mgmt_tag_tim_template->data[0] = gl_beacon_txrx_config.dtim_count; //Note: this field is going to be maintained by CPU_LOW, so it doesn't matter
                                                                         // if we write anything to it.
    mgmt_tag_tim_template->data[1] = gl_beacon_txrx_config.dtim_period;
    mgmt_tag_tim_template->data[2] = tim_control;       //TIM Control (top 7 bits are offset for partial map)
    if(gl_dtim_mcast_buffer_enable == 0){
        mgmt_tag_tim_template->data[3] |= tim_control&1;    //Per 10.2.1.3 in 802.11-2012: AID 0 is treated as
                                                            //the multicast buffer state
    }
    tx_frame_info->length += (next_mgmt_tag_length - existing_mgmt_tag_length);

    if(unlock_tx_pkt_buf(TX_PKT_BUF_BEACON) != PKT_BUF_MUTEX_SUCCESS){
        xil_printf("Error: Unable to unlock Beacon packet buffer during update_tim_tag_all\n");
    }
    return;

}

/*****************************************************************************/
/**
 * @brief Poll Tx queues to select next available packet to transmit
 *
 * This function attempts to completely fill any available Tx packet buffers. If
 * DTIM multicast buffering is enabled, it will attempt to dequeue as many multicast
 * packets as possible such that PKT_BUF_GROUP_DTIM_MCAST packet buffer group is full
 * or the multicast queue is empty (whichever comes first). The PKT_BUF_GROUP_GENERAL
 * packet buffer group will be filled with frames with a nested round-robing policy:
 *  1) The function will alternate between dequeueing management and data frames in order
 *     to prioritize time-critical management responses like authentication and assocation
 *     response frames.
 *  2) Data frames will be dequeued round-robin for each associated station. If DTIM multicast
 *     buffering is disabled, the multicast queue will be treated like an associated station in
 *     this policy.
 *
 *****************************************************************************/
#define NUM_QUEUE_GROUPS 2
typedef enum queue_group_t{
    MGMT_QGRP,
    DATA_QGRP
} queue_group_t;

void poll_tx_queues(){
    interrupt_state_t curr_interrupt_state;
    dl_entry* tx_queue_entry;
    u32 u_i;
    s32 s_i;

    int num_pkt_bufs_avail;
    int poll_loop_cnt;

    // Remember the next group to poll between calls to this function
    //   This implements the ping-pong poll between the MGMT_QGRP and DATA_QGRP groups
    static queue_group_t next_queue_group = MGMT_QGRP;
    queue_group_t curr_queue_group;

    // Remember the last queue polled between calls to this function
    //   This implements the round-robin poll of queues in the DATA_QGRP group
    static station_info_entry_t* next_station_info_entry = NULL;
    station_info_entry_t* curr_station_info_entry;

    station_info_t* curr_station_info;

    // Stop interrupts for all processing below - this avoids many possible race conditions,
    //  like new packets being enqueued or stations joining/leaving the BSS
    curr_interrupt_state = wlan_platform_intc_stop();

    // First handle the general packet buffer group
    num_pkt_bufs_avail = wlan_mac_num_tx_pkt_buf_available(PKT_BUF_GROUP_GENERAL);

    // This loop will (at most) check every queue twice
    //  This handles the case of a single non-empty queue needing to supply packets
    //  for both GENERAL packet buffers
    poll_loop_cnt = 0;
    while((num_pkt_bufs_avail > 0) && (poll_loop_cnt < (2*NUM_QUEUE_GROUPS))) {
        poll_loop_cnt++;
        curr_queue_group = next_queue_group;

        if(curr_queue_group == MGMT_QGRP) {
            // Poll the management queue on this loop, data queues on next loop
            next_queue_group = DATA_QGRP;
            tx_queue_entry = queue_dequeue(mgmt_qid);
            if(tx_queue_entry) {
                // Update the packet buffer group
                ((tx_80211_queue_buffer_t*)(tx_queue_entry->data))->tx_queue_details.pkt_buf_group = PKT_BUF_GROUP_GENERAL;
                // Successfully dequeued a management packet - transmit and checkin
                wlan_mac_transmit_wireless(tx_queue_entry);
                //continue the loop
                num_pkt_bufs_avail--;
                continue;
            }
        } else {
            // Poll the data queues on this loop, management queue on next loop
            next_queue_group = MGMT_QGRP;

            if(pause_data_queue) {
                // Data queues are paused - skip any dequeue attempts and continue the loop
                continue;
            }

            for(u_i = 0; u_i < (active_network_info->members.length + 1); u_i++) {
                // Resume polling data queues from where we stopped on the previous call
                curr_station_info_entry = next_station_info_entry;

                // Loop through all associated stations' queues and the broadcast queue
                if(curr_station_info_entry == NULL) {
                    next_station_info_entry = (station_info_entry_t*)(active_network_info->members.first);

                    // Only check the multicast queue in this loop when DTIM Multicast Buffering is disabled
                    if( gl_dtim_mcast_buffer_enable && gl_cpu_low_supports_dtim_mcast && (gl_beacon_txrx_config.beacon_tx_mode != NO_BEACON_TX)) {
                        // DTIM multicast buffering is enabled - skip the multicast queue
                        continue;
                    } else {
                        tx_queue_entry = queue_dequeue(mcast_qid);
                        if(tx_queue_entry) {
                            // Update the packet buffer group
                            ((tx_80211_queue_buffer_t*)(tx_queue_entry->data))->tx_queue_details.pkt_buf_group = PKT_BUF_GROUP_GENERAL;
                            // Successfully dequeued a management packet - transmit and checkin
                            wlan_mac_transmit_wireless(tx_queue_entry);
                            // Successfully dequeued a multicast packet - end the DATA_QGRP loop
                            num_pkt_bufs_avail--;
                            break;
                        }
                    }

                } else {
                    // Check the queue for an associated station
                    curr_station_info = (station_info_t*)(curr_station_info_entry->data);

                    if( station_info_is_member(&active_network_info->members, curr_station_info)) {
                        if(curr_station_info_entry == (station_info_entry_t*)(active_network_info->members.last)){
                            // We've reached the end of the table, so we wrap around to the beginning
                            next_station_info_entry = NULL;
                        } else {
                            next_station_info_entry = dl_entry_next(curr_station_info_entry);
                        }

                        if((curr_station_info->ps_state & STATION_INFO_PS_STATE_DOZE) == 0) {

                            tx_queue_entry = queue_dequeue(curr_station_info->QID);
                            if(tx_queue_entry) {
                                // Update the packet buffer group
                                ((tx_80211_queue_buffer_t*)(tx_queue_entry->data))->tx_queue_details.pkt_buf_group = PKT_BUF_GROUP_GENERAL;
                                // Successfully dequeued a management packet - transmit and checkin
                                wlan_mac_transmit_wireless(tx_queue_entry);
                                // Successfully dequeued a unicast packet for this station - end the DATA_QGRP loop
                                num_pkt_bufs_avail--;
                                break;
                            }
                        }
                    } else {
                        // This curr_station_info is invalid. Perhaps it was removed from
                        // the association table before poll_tx_queues was called. We will
                        // start the round robin checking back at broadcast.
                        next_station_info_entry = NULL;
                    } // END if(curr_station_info is BSS member)
                } // END if(multicast queue or station queue)
            } // END for loop over association table
        } // END if(MGMT or DATA queue group)
    } // END while(buffers available && keep polling)


    // Next handle the DTIM Multicast packet buffer group
    if(gl_dtim_mcast_buffer_enable && gl_cpu_low_supports_dtim_mcast && (gl_beacon_txrx_config.beacon_tx_mode != NO_BEACON_TX)) {

        num_pkt_bufs_avail = wlan_mac_num_tx_pkt_buf_available(PKT_BUF_GROUP_DTIM_MCAST);

        for(s_i=0; s_i<num_pkt_bufs_avail; s_i++) {
            // Dequeue packets until there are no more packet buffers or no more packets
            tx_queue_entry = queue_dequeue(mcast_qid);
            if(tx_queue_entry) {
                // Update the packet buffer group
                ((tx_80211_queue_buffer_t*)(tx_queue_entry->data))->tx_queue_details.pkt_buf_group = PKT_BUF_GROUP_DTIM_MCAST;
                // Successfully dequeued a management packet - transmit and checkin
                wlan_mac_transmit_wireless(tx_queue_entry);
            } else {
                // Queue is empty - end this loop
                break;
            }
        }
    }

    wlan_platform_intc_set_state(curr_interrupt_state);
}



/*****************************************************************************/
/**
 * @brief Purges all packets from all Tx queues
 *
 * This function discards all currently en-queued packets awaiting transmission and returns all
 * queue entries to the free pool.
 *
 * This function does not discard packets already submitted to the lower-level MAC for transmission
 *
 * @param None
 * @return None
 *****************************************************************************/
void purge_all_wireless_tx_queue(){
    station_info_entry_t* curr_station_info_entry;
    station_info_t* curr_station_info;

    if(active_network_info == NULL) return;

    int iter = active_network_info->members.length;

    // Purge all data transmit queues
    wlan_mac_purge_wireless_tx(mcast_qid);
    wlan_mac_purge_wireless_tx(mgmt_qid);
    curr_station_info_entry = (station_info_entry_t*)(active_network_info->members.first);

    while( (curr_station_info_entry != NULL) && (iter-- > 0)){
        curr_station_info = curr_station_info_entry->data;
        wlan_mac_purge_wireless_tx(curr_station_info->QID);
        curr_station_info_entry = dl_entry_next(curr_station_info_entry);
    }
}
#if WLAN_SW_CONFIG_ENABLE_LTG
/*****************************************************************************/
/**
 * @brief Callback to handle new Local Traffic Generator event
 *
 * This function is called when the LTG scheduler determines a traffic generator should create a new packet. The
 * behavior of this function depends entirely on the LTG payload parameters.
 *
 * The reference implementation defines 3 LTG payload types:
 *  - LTG_PYLD_TYPE_FIXED: generate 1 fixed-length packet to single destination; callback_arg is pointer to ltg_pyld_fixed struct
 *  - LTG_PYLD_TYPE_UNIFORM_RAND: generate 1 random-length packet to single destination; callback_arg is pointer to ltg_pyld_uniform_rand_t struct
 *  - LTG_PYLD_TYPE_ALL_ASSOC_FIXED: generate 1 fixed-length packet to each associated station; callback_arg is pointer to ltg_pyld_all_assoc_fixed_t struct
 *
 * @param u32 id
 *  - Unique ID of the previously created LTG
 * @param void* callback_arg
 *  - Callback argument provided at LTG creation time; interpretation depends on LTG type
 * @return None
 *****************************************************************************/
void ltg_event(u32 id, void* callback_arg){

    u32 payload_length;
    u8* addr_ra;
    u16 duration;
    u32 min_ltg_payload_length;
    station_info_t* station_info = NULL;
    station_info_entry_t* station_info_entry = NULL;
    u8 is_multicast;
    u8 queue_id;
    dl_entry* tx_queue_entry = NULL;
    tx_80211_queue_buffer_t* tx_queue_buffer = NULL;
    u8 continue_loop;
    u16 flags = TX_80211_QUEUE_BUFFER_FLAGS_FILL_UNIQ_SEQ;

    if(((ltg_pyld_hdr_t*)callback_arg)->type == LTG_PYLD_TYPE_CTRL_RESP){

        tx_queue_entry = queue_checkout();
        if(tx_queue_entry != NULL){
            tx_queue_buffer = ((tx_80211_queue_buffer_t*)(tx_queue_entry->data));

            addr_ra = ((ltg_pyld_ctrl_resp_t*)callback_arg)->addr_ra;
            duration = ((ltg_pyld_ctrl_resp_t*)callback_arg)->duration;

            if(((ltg_pyld_ctrl_resp_t*)callback_arg)->subtype == LTG_PYLD_CTRL_RESP_SUBTYPE_CTS){

                payload_length = wlan_create_cts_frame(tx_queue_buffer->pkt,
                                                       addr_ra,
                                                       duration);

                tx_queue_buffer->flags = TX_80211_QUEUE_BUFFER_FLAGS_TYPE_CTS;

            } else { //LTG_PYLD_CTRL_RESP_SUBTYPE_ACK
                payload_length = wlan_create_ack_frame(tx_queue_buffer->pkt,
                                                       addr_ra);
                tx_queue_buffer->flags = TX_80211_QUEUE_BUFFER_FLAGS_TYPE_ACK;
            }

            // Fill in metadata
            tx_queue_buffer->flags |= TX_80211_QUEUE_BUFFER_FLAGS_BYPASS_RECOVERY;
            tx_queue_buffer->length = payload_length;
            tx_queue_buffer->seg0_len = payload_length;
            tx_queue_buffer->seg1_len = 0;
            tx_queue_buffer->seg1_offset = 0;

            // With LTG_PYLD_TYPE_CTRL_RESP, we will transmit to the receive address (addr_ra) regardless of
            // whether that address is an AP that we are associated to. To do that, we need to make sure that
            // a station_info_t exists for that address
            tx_queue_buffer->station_info = station_info_create(addr_ra);

            wlan_mac_enqueue_wireless_tx(mgmt_qid, tx_queue_entry);

        }
    } else {

        if(active_network_info != NULL){
            u8* addr_da;
            switch(((ltg_pyld_hdr_t*)callback_arg)->type){
                case LTG_PYLD_TYPE_FIXED:
                    payload_length = ((ltg_pyld_fixed_t*)callback_arg)->length;
                    addr_da = ((ltg_pyld_fixed_t*)callback_arg)->addr_da;

                    station_info = station_info_create(addr_da);

                    is_multicast = wlan_addr_mcast(addr_da);
                    if(is_multicast){
                        queue_id = mcast_qid;
                    } else {
                        flags |= TX_80211_QUEUE_BUFFER_FLAGS_FILL_DURATION;
                        if(station_info_is_member(&active_network_info->members, station_info)){
                            queue_id = station_info->QID;
                        } else {
                            return;
                        }
                    }
                break;

                case LTG_PYLD_TYPE_UNIFORM_RAND:
                    payload_length = (rand()%(((ltg_pyld_uniform_rand_t*)(callback_arg))->max_length - ((ltg_pyld_uniform_rand_t*)(callback_arg))->min_length))+((ltg_pyld_uniform_rand_t*)(callback_arg))->min_length;
                    addr_da = ((ltg_pyld_fixed_t*)callback_arg)->addr_da;

                    station_info = station_info_create(addr_da);

                    is_multicast = wlan_addr_mcast(addr_da);
                    if(is_multicast){
                        queue_id = mcast_qid;
                    } else {
                        flags |= TX_80211_QUEUE_BUFFER_FLAGS_FILL_DURATION;
                        if(station_info_is_member(&active_network_info->members, station_info)){
                            queue_id = station_info->QID;
                        } else {
                            return;
                        }
                    }
                break;

                case LTG_PYLD_TYPE_ALL_ASSOC_FIXED:
                    if(active_network_info->members.length > 0){
                        flags |= TX_80211_QUEUE_BUFFER_FLAGS_FILL_DURATION;
                        station_info_entry = (station_info_entry_t*)(active_network_info->members.first);
                        station_info = (station_info_t*)station_info_entry->data;
                        addr_da = station_info_entry->addr;
                        queue_id = station_info->QID;
                        is_multicast = 0;
                        payload_length = ((ltg_pyld_all_assoc_fixed_t*)callback_arg)->length;
                    } else {
                        return;
                    }
                break;

                default:
                    xil_printf("ERROR ltg_event: Unknown LTG Payload Type! (%d)\n", ((ltg_pyld_hdr_t*)callback_arg)->type);
                    return;
                break;
            }

            do{
                continue_loop = 0;

                if(queue_length(queue_id) < max_queue_size){
                    // Checkout 1 element from the queue;
                    tx_queue_entry = queue_checkout();
                    if(tx_queue_entry != NULL){

                        // Create LTG packet
                        tx_queue_buffer = ((tx_80211_queue_buffer_t*)(tx_queue_entry->data));

                        min_ltg_payload_length = wlan_create_ltg_frame(tx_queue_buffer->pkt,
                                                                       addr_da,
                                                                       wlan_mac_addr,
                                                                       wlan_mac_addr,
                                                                       MAC_FRAME_CTRL2_FLAG_FROM_DS,
                                                                       id);

                        payload_length = WLAN_MAX(payload_length+sizeof(mac_header_80211)+WLAN_PHY_FCS_NBYTES, min_ltg_payload_length);



                        // Fill in metadata
                        tx_queue_buffer->flags = flags;
                        tx_queue_buffer->length = payload_length;
                        tx_queue_buffer->seg0_len = min_ltg_payload_length;
                        tx_queue_buffer->seg1_len = 0;
                        tx_queue_buffer->seg1_offset = 0;
                        tx_queue_buffer->station_info = station_info;

                        // Submit the new packet to the appropriate queue
                        wlan_mac_enqueue_wireless_tx(queue_id, tx_queue_entry);

                    } else {
                        // There aren't any free queue elements right now.
                        // As such, there probably isn't any point to continuing this callback.
                        // We'll return and try again once it is called the next time.
                        return;
                    }
                }

                if(((ltg_pyld_hdr_t*)callback_arg)->type == LTG_PYLD_TYPE_ALL_ASSOC_FIXED){
                    station_info_entry = dl_entry_next(station_info_entry);
                    if(station_info_entry != NULL){
                        station_info = (station_info_t*)station_info_entry->data;
                        addr_da = station_info_entry->addr;
                        queue_id = station_info->QID;
                        is_multicast = 0;
                        continue_loop = 1;
                    } else {
                        continue_loop = 0;
                    }
                } else {
                    continue_loop = 0;
                }
            } while(continue_loop == 1);
        }
    }
}
#endif //WLAN_SW_CONFIG_ENABLE_LTG


/*****************************************************************************/
/**
 * @brief Callback to handle insertion of an Ethernet reception into the corresponding wireless Tx queue
 *
 * This function is called when a new Ethernet packet is received that must be transmitted via the wireless interface.
 * The packet must be encapsulated before it is passed to this function. Ethernet encapsulation is implemented in the mac_high framework.
 *
 *****************************************************************************/
int ethernet_receive(eth_rx_queue_buffer_t* eth_rx_queue_buffer){
    tx_80211_queue_buffer_t* tx_queue_buffer;
    ethernet_header_t* eth_hdr;
    station_info_entry_t* entry;
    station_info_t* station_info;

    if(active_network_info == NULL) return 0;

    eth_hdr = (ethernet_header_t*)eth_rx_queue_buffer->pkt;

    if( (eth_hdr->ethertype != ETH_TYPE_ARP) && (eth_hdr->ethertype != ETH_TYPE_IP) ) return 0;

    // Determine how to send the packet
    if( wlan_addr_mcast(eth_hdr->dest_mac_addr) ) {
        // Send the multicast packet
        if(queue_length(mcast_qid) < max_queue_size){

            //Encapsulate the packet
            // Note: the encapsulation function handles filling in the C0/C1 lengths and C1 offset for us
            tx_queue_buffer = wlan_eth_encap( eth_rx_queue_buffer, 0 );

            tx_queue_buffer->flags = 0;

            wlan_create_data_frame_header(tx_queue_buffer->pkt,
                                          eth_hdr->dest_mac_addr,
                                          wlan_mac_addr,
                                          eth_hdr->src_mac_addr,
                                          MAC_FRAME_CTRL2_FLAG_FROM_DS);

            // Assign a station_info_t struct
            //  Notes: (1) if one exists already, it will be adopted.
            //         (2) if no heap exists for creating one, NULL is a valid
            //             value for the station_info_t*
            tx_queue_buffer->station_info = station_info_create(eth_hdr->dest_mac_addr);

            // Put the packet in the queue
            wlan_mac_enqueue_wireless_tx(mcast_qid, eth_rx_queue_buffer->pyld_queue_hdr.dle);

        } else {
            // Packet was not successfully enqueued
            return 0;
        }

    } else {
        // Check associations
        //     Is this packet meant for a station we are associated with?

        entry = station_info_find_by_addr(eth_hdr->dest_mac_addr, &active_network_info->members);

        if( entry != NULL ) {
            station_info = (station_info_t*)(entry->data);

            // Send the unicast packet
            if(queue_length(station_info->QID) < max_queue_size){

                //Encapsulate the packet
                // Note: the encapsulation function handles filling in the C0/C1 lengths and C1 offset for us
                tx_queue_buffer = wlan_eth_encap( eth_rx_queue_buffer, 0 );

                if(tx_queue_buffer){
                    // Fill in metadata
                    tx_queue_buffer->flags = TX_80211_QUEUE_BUFFER_FLAGS_FILL_DURATION;

                    wlan_create_data_frame_header(tx_queue_buffer->pkt,
                                           eth_hdr->dest_mac_addr,
                                           wlan_mac_addr,
                                           eth_hdr->src_mac_addr,
                                           MAC_FRAME_CTRL2_FLAG_FROM_DS);

                    tx_queue_buffer->station_info = station_info;

                    // Put the packet in the queue
                    wlan_mac_enqueue_wireless_tx(station_info->QID, tx_queue_buffer->pyld_queue_hdr.dle);
                } else {
                    return 0;
                }

            } else {
                // Packet was not successfully enqueued
                return 0;
            }
        } else {
            // Packet was not successfully enqueued
            return 0;
        }
    }

    // Packet successfully enqueued
    return 1;
}

//TODO: Create function to update beacon live fields (e.g. TIM bitmap)
// We may need to formalize a beacon ping/pong handshake to avoid any races
// created by CPU_HIGH modifying the beacon payload while the PHY is actively
// reading bytes out of the packet buffer to create a waveform.



/*****************************************************************************/
/**
 * @brief Check the time since the AP heard from each station
 *
 * This function will check the timestamp of the last reception from each station and send a
 * de-authentication packet to any stations that have timed out.
 *
 * @param  None
 * @return None
 *****************************************************************************/
void remove_inactive_station_infos() {

    u32 aid;
    u64 time_since_last_activity;
    station_info_t* curr_station_info;
    dl_entry* curr_station_info_entry;
    dl_entry* next_station_info_entry;
    time_hr_min_sec_t time_hr_min_sec;

    if(active_network_info == NULL) return;

    next_station_info_entry = active_network_info->members.first;

    while(next_station_info_entry != NULL) {
        curr_station_info_entry = next_station_info_entry;
        next_station_info_entry = dl_entry_next(curr_station_info_entry);

        curr_station_info = (station_info_t*)(curr_station_info_entry->data);
        time_since_last_activity = (get_system_time_usec() - curr_station_info->latest_rx_timestamp);

        // De-authenticate the station if we have timed out and we have not disabled this check for the station
        if((time_since_last_activity > ASSOCIATION_TIMEOUT_US) && ((curr_station_info->flags & STATION_INFO_FLAG_DISABLE_ASSOC_CHECK) == 0)){

            aid = deauthenticate_station( curr_station_info );

            if (aid != 0) {
                xil_printf("\n\nDisassociation due to inactivity:\n");
            }
        }
    }

    next_station_info_entry = authenticated_unassociated_stations.first;

    while(next_station_info_entry != NULL) {
        curr_station_info_entry = next_station_info_entry;
        next_station_info_entry = dl_entry_next(curr_station_info_entry);

        curr_station_info = (station_info_t*)(curr_station_info_entry->data);
        time_since_last_activity = (get_system_time_usec() - curr_station_info->latest_rx_timestamp);

        // De-authenticate the station if we have timed out and we have not disabled this check for the station
        if((time_since_last_activity > ASSOCIATION_TIMEOUT_US) && ((curr_station_info->flags & STATION_INFO_FLAG_DISABLE_ASSOC_CHECK) == 0)){

            station_info_remove_from_list(&authenticated_unassociated_stations, curr_station_info->addr);

            time_hr_min_sec = wlan_mac_time_to_hr_min_sec(get_system_time_usec());

            xil_printf("*%dh:%02dm:%02ds* STA %02x:%02x:%02x:%02x:%02x:%02x has disassociated\n",
                    time_hr_min_sec.hr, time_hr_min_sec.min, time_hr_min_sec.sec,
                    curr_station_info->addr[0], curr_station_info->addr[1], curr_station_info->addr[2],
                    curr_station_info->addr[3], curr_station_info->addr[4], curr_station_info->addr[5]);

            // Remove the "keep" flag for this station_info so the framework can cleanup later.
            curr_station_info->flags &= ~STATION_INFO_FLAG_KEEP;
        }
    }
}



/*****************************************************************************/
/**
 * @brief Process received MPDUs
 *
 * This callback function will process all the received MPDUs.
 *
 * This function must implement the state machine that will allow a station to join the AP.
 *
 * @param  void* pkt_buf_addr
 *     - Packet buffer address;  Contains the contents of the MPDU as well as other packet information from CPU low
 * @param  station_info_t * station_info
 *     - Pointer to metadata about the station from which this frame was received
 * @param  rx_common_entry* rx_event_log_entry
 *     - Pointer to the log entry created for this reception by the MAC High Framework
 * @return u32 flags
 *
 *****************************************************************************/
u32 mpdu_rx_process(void* pkt_buf_addr, station_info_t* station_info, rx_common_entry* rx_event_log_entry) {

    rx_frame_info_t* rx_frame_info = (rx_frame_info_t*)pkt_buf_addr;
    u8* rx_mac_payload = (u8*)pkt_buf_addr + PHY_RX_PKT_BUF_MPDU_OFFSET;
    u8* mac_payload_ptr_u8 = rx_mac_payload; // Make a copy of rx_mac_payload that can be modified while traversing through tagged parameters.

    mac_header_80211* rx_80211_header = (mac_header_80211*)(rx_mac_payload);
    mac_header_80211* tx_80211_header;

    u8 send_response = 0;
    u16 tx_length;
    u16 rx_seq;
    dl_entry* tx_queue_entry;
    tx_80211_queue_buffer_t* tx_queue_buffer;
    char ssid[SSID_LEN_MAX];
    u8 ssid_length = 0;
    u8 sta_is_ht_capable = 0;
    u8 sta_is_associated = 0;
    u8 sta_is_authenticated = 0;

    station_info_entry_t* associated_station_entry = NULL;
    station_info_t* associated_station = NULL;
    station_info_t* auth_unassoc_station_info = NULL;

    u8 unicast_to_me;
    u8 to_multicast;
    u8 eth_send;
    u8 allow_auth = 0;

    time_hr_min_sec_t time_hr_min_sec;

    u16 rx_length = rx_frame_info->phy_details.length;
    u32 return_val = 0;

    // If this function was passed a CTRL frame (e.g., CTS, ACK), then we should just quit.
    // The only reason this occured was so that it could be logged in the line above.
    if((rx_80211_header->frame_control_1 & 0xF) == MAC_FRAME_CTRL1_TYPE_CTRL){
        goto mpdu_rx_process_end;
    }

    // Determine if this STA is currently associated to the active_bss_info
    sta_is_associated = station_info_is_member(&active_network_info->members, station_info);

    sta_is_authenticated = (sta_is_associated || station_info_is_member(&authenticated_unassociated_stations, station_info));

    // Determine destination of packet
    unicast_to_me = wlan_addr_eq(rx_80211_header->address_1, wlan_mac_addr);
    to_multicast  = wlan_addr_mcast(rx_80211_header->address_1);

    // If the packet is good (ie good FCS) and it is destined for me, then process it
    if( rx_frame_info->flags & RX_FRAME_INFO_FLAGS_FCS_GOOD){
        
        // Sequence number is 12 MSB of seq_control field
        rx_seq         = ((rx_80211_header->sequence_control) >> 4) & 0xFFF;

        // Check if this was a duplicate reception
        //   - Packet is unicast and directed towards me
        //   - Packet has the RETRY bit set to 1 in the second frame control byte
        //   - Received seq num matched previously received seq num for this STA
        if( (station_info != NULL) && unicast_to_me ){
            if( ((rx_80211_header->frame_control_2) & MAC_FRAME_CTRL2_FLAG_RETRY) && (station_info->latest_rx_seq == rx_seq) ) {
                if(rx_event_log_entry != NULL){
                    rx_event_log_entry->flags |= RX_FLAGS_DUPLICATE;
                    return_val |= MAC_RX_CALLBACK_RETURN_FLAG_DUP;
                }
            } else {
                station_info->latest_rx_seq = rx_seq;
            }   
        }

        if( sta_is_associated ){
            // Update PS state
            if((rx_80211_header->frame_control_2) & MAC_FRAME_CTRL2_FLAG_POWER_MGMT){
                station_info->ps_state |= STATION_INFO_PS_STATE_DOZE;
            } else {
                station_info->ps_state &= ~STATION_INFO_PS_STATE_DOZE;
                poll_tx_queues();
            }

            if( return_val & MAC_RX_CALLBACK_RETURN_FLAG_DUP ) {
                // Finish the function and do not de-encapsulate
                goto mpdu_rx_process_end;
            } 
        }

        if(unicast_to_me || to_multicast){
            // Process the packet
            switch(rx_80211_header->frame_control_1) {
                //---------------------------------------------------------------------
                case MAC_FRAME_CTRL1_SUBTYPE_QOSDATA:
                case MAC_FRAME_CTRL1_SUBTYPE_DATA:
                    // Data packet
                    //   - Determine if this packet is from an associated station
                    //   - Depending on the type and destination, transmit the packet wirelessly or over the wired network
                    //

                    if( sta_is_associated ){

                        // MPDU is flagged as destined to the DS
                        if((rx_80211_header->frame_control_2) & MAC_FRAME_CTRL2_FLAG_TO_DS) {
                            eth_send = 1;

                            // Check if this is a multicast packet
                            if(wlan_addr_mcast(rx_80211_header->address_3)){
                                // Send the data packet over wireless
                                tx_queue_entry = queue_checkout();

                                if(tx_queue_entry != NULL){
                                    tx_queue_buffer = (tx_80211_queue_buffer_t*)(tx_queue_entry->data);

                                    wlan_create_data_frame_header(tx_queue_buffer->pkt,
                                                                  rx_80211_header->address_3,
                                                                  wlan_mac_addr,
                                                                  rx_80211_header->address_2,
                                                                  MAC_FRAME_CTRL2_FLAG_FROM_DS);

                                    // Overwrite packet type with just-received packet type. This will allow
                                    // relaying of QOSDATA frames
                                    tx_80211_header = ((mac_header_80211*)(tx_queue_buffer->pkt));
                                    tx_80211_header->frame_control_1 = rx_80211_header->frame_control_1;

                                    // Fill in the data
                                    wlan_mac_high_cdma_start_transfer(tx_queue_buffer->pkt + sizeof(mac_header_80211),
                                                                      rx_mac_payload + sizeof(mac_header_80211),
                                                                      rx_length - sizeof(mac_header_80211));

                                    // Fill in the metadata
                                    tx_queue_buffer->flags = 0;
                                    tx_queue_buffer->length = rx_length;
                                    tx_queue_buffer->seg0_len = rx_length;
                                    tx_queue_buffer->seg1_len = 0;
                                    tx_queue_buffer->seg1_offset = 0;
                                    tx_queue_buffer->station_info = station_info_create(rx_80211_header->address_3);

                                    // Make sure the DMA transfer is complete
                                    wlan_mac_high_cdma_finish_transfer();

                                    // Put the packet in the queue
                                    wlan_mac_enqueue_wireless_tx(mcast_qid, tx_queue_entry);

                                }
                            } else {
                                // Packet is not a multicast packet.  Check if it is destined for one of our stations
                                if(active_network_info != NULL){
                                    associated_station_entry = station_info_find_by_addr(rx_80211_header->address_3, &active_network_info->members);
                                }
                                if(associated_station_entry != NULL){
                                    associated_station = (station_info_t*)(associated_station_entry->data);

                                    // Send the data packet over the wireless to our station
                                    tx_queue_entry = queue_checkout();

                                    if(tx_queue_entry != NULL){
                                        tx_queue_buffer = (tx_80211_queue_buffer_t*)(tx_queue_entry->data);

                                        wlan_create_data_frame_header(tx_queue_buffer->pkt,
                                                                      rx_80211_header->address_3,
                                                                      wlan_mac_addr,
                                                                      rx_80211_header->address_2,
                                                                      MAC_FRAME_CTRL2_FLAG_FROM_DS);

                                        // Overwrite packet type with just-received packet type. This will allow
                                        // relaying of QOSDATA frames
                                        tx_80211_header = ((mac_header_80211*)(tx_queue_buffer->pkt));
                                        tx_80211_header->frame_control_1 = rx_80211_header->frame_control_1;

                                        // Fill in the data
                                        wlan_mac_high_cdma_start_transfer(tx_queue_buffer->pkt + sizeof(mac_header_80211),
                                                                          rx_mac_payload + sizeof(mac_header_80211),
                                                                          rx_length - sizeof(mac_header_80211));

                                        // Fill in the metadata
                                        tx_queue_buffer->flags = TX_80211_QUEUE_BUFFER_FLAGS_FILL_DURATION;
                                        tx_queue_buffer->length = rx_length;
                                        tx_queue_buffer->seg0_len = rx_length;
                                        tx_queue_buffer->seg1_len = 0;
                                        tx_queue_buffer->seg1_offset = 0;
                                        tx_queue_buffer->station_info = associated_station;

                                        // Make sure the DMA transfer is complete
                                        wlan_mac_high_cdma_finish_transfer();

                                        // Put the packet in the queue
                                        wlan_mac_enqueue_wireless_tx(associated_station->QID, tx_queue_entry);

                                        // Given we sent the packet wirelessly to our stations, if we do not allow Ethernet transmissions
                                        //   of wireless transmissions, then do not send over Ethernet
                                        #ifndef ALLOW_ETH_TX_OF_WIRELESS_TX
                                        eth_send = 0;
                                        #endif
                                    }
                                }
                            }

                            // Encapsulate the packet and send over the wired network
                            if(eth_send){
#if WLAN_SW_CONFIG_ENABLE_ETH_BRIDGE
                                wlan_eth_decap_and_send(rx_mac_payload,
                                                        rx_80211_header->address_3,
                                                        rx_80211_header->address_2,
                                                        rx_length,
                                                        0);
#endif
                            }
                        }
                    } else {
                        // Packet was not from an associated station
                        //   - Print a WARNING and send a de-authentication to trigger a re-association
                        //
                        //
                        if(unicast_to_me){

                            // Received a data frame from a STA that claims to be associated with this AP but is not in the AP association table
                            //   Discard the MPDU and reply with a de-authentication frame to trigger re-association at the STA
                            wlan_printf(PL_WARNING, "Data from non-associated station: [%x %x %x %x %x %x], issuing de-authentication\n", rx_80211_header->address_2[0],rx_80211_header->address_2[1],rx_80211_header->address_2[2],rx_80211_header->address_2[3],rx_80211_header->address_2[4],rx_80211_header->address_2[5]);
                            wlan_printf(PL_WARNING, "Address 3: [%x %x %x %x %x %x]\n", rx_80211_header->address_3[0],rx_80211_header->address_3[1],rx_80211_header->address_3[2],rx_80211_header->address_3[3],rx_80211_header->address_3[4],rx_80211_header->address_3[5]);

                            // Send de-authentication packet to the station
                            tx_queue_entry = queue_checkout();

                            if(tx_queue_entry != NULL){
                                tx_queue_buffer = (tx_80211_queue_buffer_t*)(tx_queue_entry->data);

                                tx_length = wlan_create_deauth_frame(tx_queue_buffer->pkt,
                                                                     rx_80211_header->address_2,
                                                                     wlan_mac_addr,
                                                                     wlan_mac_addr,
                                                                     DEAUTH_REASON_NONASSOCIATED_STA);

                                // Fill in metadata
                                tx_queue_buffer->length = tx_length;
                                tx_queue_buffer->seg0_len = tx_length;
                                tx_queue_buffer->seg1_len = 0;
                                tx_queue_buffer->seg1_offset = 0;
                                tx_queue_buffer->station_info = station_info;

                                // Put the packet in the queue
                                wlan_mac_enqueue_wireless_tx(mgmt_qid, tx_queue_entry);
                            }
                        }
                    } // END if(associated_station != NULL)
                break;


                //---------------------------------------------------------------------
                case (MAC_FRAME_CTRL1_SUBTYPE_PROBE_REQ):
                    // Probe Request Packet
                    //   - Check that this packet is to the broadcast address
                    //   - Look at the tagged parameters
                    //   - Depending on the parameters, send a probe response
                    //
                    if(wlan_addr_eq(rx_80211_header->address_3, bcast_addr) ||
                            wlan_addr_eq(rx_80211_header->address_3, wlan_mac_addr)) {
                        mac_payload_ptr_u8 += sizeof(mac_header_80211);

                        // Loop through tagged parameters
                        while(((u32)mac_payload_ptr_u8 -  (u32)rx_mac_payload)<= (rx_length - WLAN_PHY_FCS_NBYTES)){

                            // What kind of tag is this?
                            switch(mac_payload_ptr_u8[0]){
                                //-----------------------------------------------------
                                case MGMT_TAG_SSID:
                                    // SSID parameter set
                                    if((active_network_info != NULL) &&
                                       ((mac_payload_ptr_u8[1]==0) || // Wildcard SSID is zero-length
                                        ((mac_payload_ptr_u8[1] == strnlen(active_network_info->bss_config.ssid, SSID_LEN_MAX)) && // Check for equal lengths first
                                        (memcmp(mac_payload_ptr_u8+2, (u8*)active_network_info->bss_config.ssid, mac_payload_ptr_u8[1])==0)))) {
                                        // Send response if Probe Request contained wildcard SSID
                                        //  or SSID matching the SSID of this AP's BSS
                                        send_response = 1;
                                    }
                                break;

                                //-----------------------------------------------------
                                case MGMT_TAG_SUPPORTED_RATES:
                                    // Supported rates
                                break;

                                //-----------------------------------------------------
                                case MGMT_TAG_EXTENDED_SUPPORTED_RATES:
                                    // Extended supported rates
                                break;

                                //-----------------------------------------------------
                                case MGMT_TAG_DSSS_PARAMETER_SET:
                                    // DS Parameter set (e.g. channel)
                                break;
                            }

                            // Move up to the next tag
                            mac_payload_ptr_u8 += mac_payload_ptr_u8[1]+2;
                        }

                        if((active_network_info != NULL) && send_response) {

                            // Create a probe response frame
                            tx_queue_entry = queue_checkout();

                            if(tx_queue_entry != NULL){
                                tx_queue_buffer = (tx_80211_queue_buffer_t*)(tx_queue_entry->data);

                                tx_length = wlan_create_probe_resp_frame( tx_queue_buffer->pkt,
                                                                          rx_80211_header->address_2,
                                                                          wlan_mac_addr,
                                                                          wlan_mac_addr,
                                                                          active_network_info );


                                // Fill in metadata
                                tx_queue_buffer->flags = TX_80211_QUEUE_BUFFER_FLAGS_FILL_DURATION | TX_80211_QUEUE_BUFFER_FLAGS_FILL_TIMESTAMP;
                                tx_queue_buffer->length = tx_length;
                                tx_queue_buffer->seg0_len = tx_length;
                                tx_queue_buffer->seg1_len = 0;
                                tx_queue_buffer->seg1_offset = 0;
                                tx_queue_buffer->station_info = station_info;

                                // Put the packet in the queue
                                wlan_mac_enqueue_wireless_tx(mgmt_qid, tx_queue_entry);
                            }

                            // Finish the function
                            goto mpdu_rx_process_end;
                        }
                    }
                break;


                //---------------------------------------------------------------------
                case (MAC_FRAME_CTRL1_SUBTYPE_AUTH):
                    // Authentication Packet
                    //   - Check if authentication is allowed (note: if the station
                    //   - Potentially send authentication response
                    //
                    if( sta_is_associated || (wlan_addr_eq(rx_80211_header->address_3, wlan_mac_addr) && wlan_mac_addr_filter_is_allowed(rx_80211_header->address_2)) ) {
                        mac_payload_ptr_u8 += sizeof(mac_header_80211);
                        switch(((authentication_frame*)mac_payload_ptr_u8)->auth_algorithm ){
                            case AUTH_ALGO_OPEN_SYSTEM:
                                allow_auth = 1;
                            break;
                        }
                    }

                    // Only send response if the packet was from a requester
                    //
                    if((active_network_info != NULL) && ((authentication_frame*)mac_payload_ptr_u8)->auth_sequence == AUTH_SEQ_REQ){

                        // Only send response if we are allowing authentication and there is room in the authenticated_unassociated_stations list.
                        //  Note: the station from which this MAC_FRAME_CTRL1_SUBTYPE_AUTH was received may already be in the authenticated_unassociated_stations
                        //  list, so this should be accounted for when comparing the list length to MAX_NUM_AUTH
                        if(allow_auth && ( (authenticated_unassociated_stations.length-(sta_is_authenticated && (!sta_is_associated))) < MAX_NUM_AUTH ) ){

                            //Only proceed if:
                            // (1) The authentication type was AUTH_ALGO_OPEN_SYSTEM
                            //      and
                            // (2) The number of currently authenticated stations (not counting this station if it
                            //      is already authenticated) is less than MAX_NUM_AUTH
                            if(sta_is_associated == 0){
                                // This station wasn't already authenticated/associated (state 4), so manually add it to the
                                // authenticated/unassociated (state 2) list.
                                //     - Set ht_capable argument to 0.  This will be updated with the correct value when the
                                //       node moves from the state 2 list during association.

                                auth_unassoc_station_info = station_info_add_to_list(&authenticated_unassociated_stations, rx_80211_header->address_2);

                                if(auth_unassoc_station_info != NULL){
                                    auth_unassoc_station_info->flags |= STATION_INFO_FLAG_KEEP;
                                    time_hr_min_sec = wlan_mac_time_to_hr_min_sec(get_system_time_usec());
                                    xil_printf("*%dh:%02dm:%02ds* STA %02x:%02x:%02x:%02x:%02x:%02x is now authenticated / unassociated\n",
                                            time_hr_min_sec.hr, time_hr_min_sec.min, time_hr_min_sec.sec,
                                            rx_80211_header->address_2[0], rx_80211_header->address_2[1], rx_80211_header->address_2[2],
                                            rx_80211_header->address_2[3], rx_80211_header->address_2[4], rx_80211_header->address_2[5]);
                                }
                            }

                            // Create a successful authentication response frame
                            tx_queue_entry = queue_checkout();

                            if(tx_queue_entry != NULL){
                                tx_queue_buffer = (tx_80211_queue_buffer_t*)(tx_queue_entry->data);

                                tx_length = wlan_create_auth_frame( tx_queue_buffer->pkt,
                                                                    rx_80211_header->address_2,
                                                                    wlan_mac_addr,
                                                                    wlan_mac_addr,
                                                                    AUTH_ALGO_OPEN_SYSTEM,
                                                                    AUTH_SEQ_RESP,
                                                                    STATUS_SUCCESS);
                                // Fill in metadata
                                tx_queue_buffer->flags = TX_80211_QUEUE_BUFFER_FLAGS_FILL_DURATION;
                                tx_queue_buffer->length = tx_length;
                                tx_queue_buffer->seg0_len = tx_length;
                                tx_queue_buffer->seg1_len = 0;
                                tx_queue_buffer->seg1_offset = 0;
                                tx_queue_buffer->station_info = station_info;

                                // Put the packet in the queue
                                wlan_mac_enqueue_wireless_tx(mgmt_qid, tx_queue_entry);
                            }

                            // Finish the function
                            goto mpdu_rx_process_end;

                        } else {
                            // Create a unsuccessful authentication response frame
                            tx_queue_entry = queue_checkout();

                            if(tx_queue_entry != NULL){
                                tx_queue_buffer = (tx_80211_queue_buffer_t*)(tx_queue_entry->data);

                                tx_length = wlan_create_auth_frame( tx_queue_buffer->pkt,
                                                                    rx_80211_header->address_2,
                                                                    wlan_mac_addr,
                                                                    wlan_mac_addr,
                                                                    AUTH_ALGO_OPEN_SYSTEM,
                                                                    AUTH_SEQ_RESP,
                                                                    STATUS_AUTH_REJECT_UNSPECIFIED);
                                // Fill in metadata
                                tx_queue_buffer->flags = TX_80211_QUEUE_BUFFER_FLAGS_FILL_DURATION;
                                tx_queue_buffer->length = tx_length;
                                tx_queue_buffer->seg0_len = tx_length;
                                tx_queue_buffer->seg1_len = 0;
                                tx_queue_buffer->seg1_offset = 0;
                                tx_queue_buffer->station_info = station_info;

                                // Put the packet in the queue
                                wlan_mac_enqueue_wireless_tx(mgmt_qid, tx_queue_entry);
                            }
                        }

                        // Finish the function
                        goto mpdu_rx_process_end;
                    }
                break;


                //---------------------------------------------------------------------
                case (MAC_FRAME_CTRL1_SUBTYPE_ASSOC_REQ):
                case (MAC_FRAME_CTRL1_SUBTYPE_REASSOC_REQ):
                {
                    u32 reject_association = 1;

                    if(station_info != NULL){

                    // Association Request / Re-association Request

                    // Parse the tagged parameters
                    mac_payload_ptr_u8 = mac_payload_ptr_u8 + sizeof(mac_header_80211) + sizeof(association_req_frame);
                    while ((((u32)mac_payload_ptr_u8) - ((u32)rx_mac_payload)) < (rx_length - WLAN_PHY_FCS_NBYTES)) {
                        // Parse each of the tags
                        switch(mac_payload_ptr_u8[0]){

                            //-------------------------------------------------
                            case MGMT_TAG_SSID:
                                // SSID parameter set
                                //
                                strncpy(ssid, (char*)(&(mac_payload_ptr_u8[2])), SSID_LEN_MAX);
                                ssid_length = WLAN_MIN(mac_payload_ptr_u8[1],SSID_LEN_MAX);
                            break;


                            //-------------------------------------------------
                            case MGMT_TAG_HT_CAPABILITIES:
                                // This station is capable of HT Tx and Rx
                                sta_is_ht_capable = 1;
                            break;
                        }

                        // Increment packet pointer to the next tag
                        mac_payload_ptr_u8 += mac_payload_ptr_u8[1]+2;
                    }

                    //   - Check if the packet is for this BSS. Necessary Criteria:
                    //      - RA is unicast and directed to this node's wlan_mac_address
                    //      - SSID string in payload of reception matches this BSS's SSID string
                    //      - BSSID matches this BSS's ID
                    if( unicast_to_me &&
                        (strncmp(ssid, active_network_info->bss_config.ssid, ssid_length) == 0) &&
                        (active_network_info != NULL) && wlan_addr_eq(rx_80211_header->address_3, active_network_info->bss_config.bssid)) {

                        // Check if we have authenticated this TA yet have not associated it.
                        // Note: We cannot use the sta_is_authenticated boolean for this, as this also
                        //  includes fully associated stations.

                            if( sta_is_associated || (active_network_info->members.length < MAX_NUM_ASSOC) ) reject_association = 0;

                            if((reject_association == 0) && station_info_is_member(&authenticated_unassociated_stations, station_info)){

                            station_info_remove_from_list(&authenticated_unassociated_stations, rx_80211_header->address_2);

                            // NOTE: The STATION_INFO_FLAG_KEEP bit will still be raised despite having removed the
                            //  station_info from the authenticated_unassociated_stations list. This is intentional,
                            //  as we are about to add the station_info the the fully associated list.

                            // Add the station info
                            //     - Set ht_capable argument to 0.  This will be updated below with the
                            //       correct value from the tagged parameters in the association request.
                            if (network_info_add_member(active_network_info, rx_80211_header->address_2, max_queue_size)) {
                                time_hr_min_sec = wlan_mac_time_to_hr_min_sec(get_system_time_usec());
                                xil_printf("*%dh:%02dm:%02ds* STA %02x:%02x:%02x:%02x:%02x:%02x is now associated\n",
                                        time_hr_min_sec.hr, time_hr_min_sec.min, time_hr_min_sec.sec,
                                        rx_80211_header->address_2[0], rx_80211_header->address_2[1], rx_80211_header->address_2[2],
                                        rx_80211_header->address_2[3], rx_80211_header->address_2[4], rx_80211_header->address_2[5]);
                            }

                            wlan_platform_high_userio_disp_status(USERIO_DISP_STATUS_MEMBER_LIST_UPDATE, active_network_info->members.length);
                        }

                        if( reject_association == 0 ) {
                            // Zero the HT_CAPABLE flag
                            if(sta_is_ht_capable){
                                station_info->capabilities |= STATION_INFO_CAPABILITIES_HT_CAPABLE;
                            } else {
                                station_info->capabilities &= ~STATION_INFO_CAPABILITIES_HT_CAPABLE;
                            }

                            // Do not allow Mango nodes to time out
                            if(wlan_mac_addr_is_mango(rx_80211_header->address_2)){
                                station_info->flags |= STATION_INFO_FLAG_DISABLE_ASSOC_CHECK;
                            }


                            //
                            // TODO:  (Optional) Log association state change
                            //

                            // Create a successful association response frame
                            tx_queue_entry = queue_checkout();

                            if(tx_queue_entry != NULL){
                                tx_queue_buffer = (tx_80211_queue_buffer_t*)(tx_queue_entry->data);

                                tx_length = wlan_create_association_response_frame(tx_queue_buffer->pkt,
                                                                                   rx_80211_header->address_2,
                                                                                   wlan_mac_addr,
                                                                                   active_network_info->bss_config.bssid,
                                                                                   STATUS_SUCCESS,
                                                                                   station_info->ID,
                                                                                   active_network_info);

                                // Fill in metadata
                                tx_queue_buffer->flags = TX_80211_QUEUE_BUFFER_FLAGS_FILL_DURATION;
                                tx_queue_buffer->length = tx_length;
                                tx_queue_buffer->seg0_len = tx_length;
                                tx_queue_buffer->seg1_len = 0;
                                tx_queue_buffer->seg1_offset = 0;
                                tx_queue_buffer->station_info = station_info;

                                // Put the packet in the queue
                                wlan_mac_enqueue_wireless_tx(station_info->QID, tx_queue_entry);
                            }

                            // Finish the function
                            goto mpdu_rx_process_end;

                        } else {
                            // Create an unsuccessful association response frame
                            tx_queue_entry = queue_checkout();

                            if(tx_queue_entry != NULL){
                                tx_queue_buffer = (tx_80211_queue_buffer_t*)(tx_queue_entry->data);

                                tx_length = wlan_create_association_response_frame(tx_queue_buffer->pkt,
                                                                                   rx_80211_header->address_2,
                                                                                   wlan_mac_addr,
                                                                                   active_network_info->bss_config.bssid,
                                                                                   STATUS_REJECT_TOO_MANY_ASSOCIATIONS,
                                                                                   0,
                                                                                   active_network_info);

                                // Fill in metadata
                                tx_queue_buffer->flags = TX_80211_QUEUE_BUFFER_FLAGS_FILL_DURATION;
                                tx_queue_buffer->length = tx_length;
                                tx_queue_buffer->seg0_len = tx_length;
                                tx_queue_buffer->seg1_len = 0;
                                tx_queue_buffer->seg1_offset = 0;
                                tx_queue_buffer->station_info = station_info;

                                // Put the packet in the queue
                                wlan_mac_enqueue_wireless_tx(mgmt_qid, tx_queue_entry);

                            }

                            // Finish the function
                            goto mpdu_rx_process_end;
                        }
                    }
                    }
                }
                break;


                //---------------------------------------------------------------------
                case (MAC_FRAME_CTRL1_SUBTYPE_DISASSOC):
                    // Disassociation
                    //   - Log the association state change
                    //   - Remove the association and update the display
                    //
                    if(active_network_info != NULL){

                        // Note: Since we are no longer keeping this station_info, we should ensure it is present
                        //  in neither the fully associated list or the authenticated-only list

                        if(sta_is_associated){
                            network_info_remove_member(active_network_info, rx_80211_header->address_2);
                        }

                        station_info_remove_from_list(&authenticated_unassociated_stations, rx_80211_header->address_2);

                        time_hr_min_sec = wlan_mac_time_to_hr_min_sec(get_system_time_usec());

                        xil_printf("*%dh:%02dm:%02ds* STA %02x:%02x:%02x:%02x:%02x:%02x has disassociated\n",
                                time_hr_min_sec.hr, time_hr_min_sec.min, time_hr_min_sec.sec,
                                rx_80211_header->address_2[0], rx_80211_header->address_2[1], rx_80211_header->address_2[2],
                                rx_80211_header->address_2[3], rx_80211_header->address_2[4], rx_80211_header->address_2[5]);

                        // Lower the KEEP flag so that the station_info_
                        if(station_info != NULL) station_info->flags &= ~STATION_INFO_FLAG_KEEP;

                        wlan_platform_high_userio_disp_status(USERIO_DISP_STATUS_MEMBER_LIST_UPDATE, active_network_info->members.length);
                    }
                break;

                case (MAC_FRAME_CTRL1_SUBTYPE_NULLDATA):
                break;

                //---------------------------------------------------------------------
                default:
                    //This should be left as a verbose print. It occurs often when communicating with mobile devices since they tend to send
                    //null data frames (type: DATA, subtype: 0x4) for power management reasons.
                    wlan_printf(PL_VERBOSE, "Received unknown frame control type/subtype %x\n",rx_80211_header->frame_control_1);

                break;
            }
        }

        goto mpdu_rx_process_end;

    } else {
        // Process any Bad FCS packets
        goto mpdu_rx_process_end;
    }

    // Finish any processing for the RX MPDU process
    mpdu_rx_process_end:

    // Currently, asynchronous transmission of log entries is not supported
    //
    // if (rx_event_log_entry != NULL) {
    //     wn_transmit_log_entry((void *)rx_event_log_entry);
    // }

    return return_val;
}



/*****************************************************************************/
/**
 *
 *****************************************************************************/
void mpdu_dequeue(tx_80211_queue_buffer_t* tx_queue_buffer){
    mac_header_80211* header;
    station_info_t* station_info;

    header = (mac_header_80211*)(tx_queue_buffer->pkt);
    station_info = tx_queue_buffer->station_info;

    if(station_info->num_linked_queue_buffer > 1){
        //If the is more data (in addition to this packet) queued for this station, we can let it know
        //in the frame_control_2 field.
        header->frame_control_2 |= MAC_FRAME_CTRL2_FLAG_MORE_DATA;
    } else {
        header->frame_control_2 &= ~MAC_FRAME_CTRL2_FLAG_MORE_DATA;
    }

}

/*****************************************************************************/
/**
 * @brief Deauthenticate given station in the Association Table
 *
 * Deauthenticate the station in the associations table
 *
 * @param  station_info_t * station_info
 *   - Station to be deauthenticated
 * @return u32 aid
 *   - AID of the station that was deauthenticated; AID of 0 is reserved to indicate failure
 *****************************************************************************/
u32  deauthenticate_station( station_info_t* station_info ) {

    dl_entry* tx_queue_entry;
    tx_80211_queue_buffer_t* tx_queue_buffer;
    u32 tx_length;
    u32 aid;
    time_hr_min_sec_t time_hr_min_sec;

    if((active_network_info == NULL) || (station_info == NULL)){
        return 0;
    }

    // Get the AID
    aid = station_info->ID;

    // Send De-authentication packet
    tx_queue_entry = queue_checkout();

    if(tx_queue_entry != NULL){
        tx_queue_buffer = (tx_80211_queue_buffer_t*)(tx_queue_entry->data);

        tx_length = wlan_create_deauth_frame(tx_queue_buffer->pkt,
                                             station_info->addr,
                                             wlan_mac_addr,
                                             wlan_mac_addr,
                                             DEAUTH_REASON_INACTIVITY);

        // Fill in metadata
        tx_queue_buffer->flags = TX_80211_QUEUE_BUFFER_FLAGS_FILL_DURATION;
        tx_queue_buffer->length = tx_length;
        tx_queue_buffer->seg0_len = tx_length;
        tx_queue_buffer->seg1_len = 0;
        tx_queue_buffer->seg1_offset = 0;
        tx_queue_buffer->station_info = station_info;

        // Put the packet in the queue
        wlan_mac_enqueue_wireless_tx(mgmt_qid, tx_queue_entry);

        // Purge any packets in the queue meant for this node
        wlan_mac_purge_wireless_tx(station_info->QID);
    }

    //
    // TODO:  (Optional) Log association state change
    //

    // Remove this STA from association list
    network_info_remove_member(active_network_info, station_info->addr);

    time_hr_min_sec = wlan_mac_time_to_hr_min_sec(get_system_time_usec());

    xil_printf("*%dh:%02dm:%02ds* STA %02x:%02x:%02x:%02x:%02x:%02x has disassociated\n",
            time_hr_min_sec.hr, time_hr_min_sec.min, time_hr_min_sec.sec,
            station_info->addr[0], station_info->addr[1], station_info->addr[2],
            station_info->addr[3], station_info->addr[4], station_info->addr[5]);

    // Remove the "keep" flag for this station_info so the framework can cleanup later.
    station_info->flags &= ~STATION_INFO_FLAG_KEEP;

    wlan_platform_high_userio_disp_status(USERIO_DISP_STATUS_MEMBER_LIST_UPDATE, active_network_info->members.length);

    return aid;
}



/*****************************************************************************/
/**
 * @brief Deauthenticate all stations in the Association Table
 *
 * Loop through all associations in the table and deauthenticate the stations
 *
 * @param  None
 * @return None
 *****************************************************************************/
void deauthenticate_all_stations(){
    interrupt_state_t curr_interrupt_state;
    station_info_t* curr_station_info;
    dl_entry* next_station_info_entry;
    dl_entry* curr_station_info_entry;
    int iter;

    if(active_network_info == NULL) return;

    iter = active_network_info->members.length;
    curr_interrupt_state = wlan_platform_intc_stop();

    next_station_info_entry = active_network_info->members.first;

    // Deauthenticate all stations and remove from the association table
    //
    // NOTE:  Cannot use a for loop for this iteration b/c we could remove
    //   elements from the list.
    while( (next_station_info_entry != NULL) && (iter-- > 0)){
        curr_station_info_entry = next_station_info_entry;
        next_station_info_entry = dl_entry_next(curr_station_info_entry);
        curr_station_info = (station_info_t*)(curr_station_info_entry->data);
        deauthenticate_station(curr_station_info);
    }

    wlan_platform_intc_set_state(curr_interrupt_state);

}

/*****************************************************************************/
/**
 * @brief Handle a reboot of CPU_LOW
 *
 * If CPU_LOW reboots, any parameters we had previously set in it will be lost.
 * This function is called to tell us that we should re-apply any previous
 * parameters we had set.
 *
 * @param  u32 type - type of MAC running in CPU_LOW
 * @return None
 *****************************************************************************/
void handle_cpu_low_reboot(u32 type){

    if(type & WLAN_EXP_LOW_SW_ID_DCF) {
        gl_cpu_low_supports_dtim_mcast = 1;
    } else {
        gl_cpu_low_supports_dtim_mcast = 0;
    }

    if(active_network_info != NULL){
        // Re-apply any Beacon Tx configurations
        wlan_mac_high_config_txrx_beacon(&gl_beacon_txrx_config);

        // Re-apply DTIM mcast buffering settings
        wlan_mac_high_enable_mcast_buffering(gl_dtim_mcast_buffer_enable);
    }
}

/*****************************************************************************/
/**
 *
 *****************************************************************************/
u32 configure_bss(bss_config_t* bss_config, u32 update_mask){
    u32 return_status = 0;
    u8 update_beacon_template = 0;
    u8 send_beacon_config_to_low = 0;
    u8 send_channel_switch_to_low = 0;

    network_info_t* local_network_info;
    interrupt_state_t curr_interrupt_state;
    station_info_t* curr_station_info;
    dl_entry* next_station_info_entry;
    dl_entry* curr_station_info_entry;
    int iter;
    time_hr_min_sec_t time_hr_min_sec;
    tx_params_t default_beacon_tx_params;

    //---------------------------------------------------------
    // 1. Check for any invalid inputs or combination of inputs
    //      First verify the requested update to the BSS configuration before
    //      modifying anything. This will prevent a partial update of BSS
    //      configuration with valid parameters before discovering an invalid
    //      parameter. Furthermore, we can update the arguments to this function
    //      with any relevant default values in the case that the arguments
    //      are not updated directly by the call to this function and the
    //      active_network_info is NULL, preventing us from inhering whatever
    //      might be there.

    if (bss_config != NULL){
        //////////////////
        if (update_mask & BSS_FIELD_MASK_BSSID) {
            if (wlan_addr_eq(bss_config->bssid, zero_addr) == 0) {
                if ((active_network_info != NULL) && wlan_addr_eq(bss_config->bssid, active_network_info->bss_config.bssid)) {
                    // The caller of this function claimed that it was updating the BSSID,
                    // but the new BSSID matches the one already specified in active_bss_info.
                    // Complete the rest of this function as if that bit in the update mask
                    // were not set
                    update_mask &= ~BSS_FIELD_MASK_BSSID;
                } else {
                    // Changing the BSSID, perform necessary argument checks
                    if (wlan_addr_eq(bss_config->bssid, wlan_mac_addr) == 0) {
                        // In the AP implementation, the BSSID provided must be
                        // the hardware MAC address of the node
                        return_status |= BSS_CONFIG_FAILURE_BSSID_INVALID;
                    }
                    if (((update_mask & BSS_FIELD_MASK_SSID) == 0) ||
                        ((update_mask & BSS_FIELD_MASK_CHAN) == 0) ||
                        ((update_mask & BSS_FIELD_MASK_BEACON_INTERVAL) == 0)) {
                        return_status |= BSS_CONFIG_FAILURE_BSSID_INSUFFICIENT_ARGUMENTS;
                    }
                }
            }
        } else {
            if (active_network_info == NULL) {
                // Cannot update BSS without specifying BSSID
                return_status |= BSS_CONFIG_FAILURE_BSSID_INSUFFICIENT_ARGUMENTS;
            }
        }
        //////////////////
        if (update_mask & BSS_FIELD_MASK_CHAN) {
            if (wlan_verify_channel(
                    wlan_mac_high_bss_channel_spec_to_radio_chan(bss_config->chan_spec)) != WLAN_SUCCESS) {
                return_status |= BSS_CONFIG_FAILURE_CHANNEL_INVALID;
            }
        }
        //////////////////
        if (update_mask & BSS_FIELD_MASK_BEACON_INTERVAL) {
            if ((bss_config->beacon_interval != BEACON_INTERVAL_NO_BEACON_TX) &&
                (bss_config->beacon_interval <  10)) {
                return_status |= BSS_CONFIG_FAILURE_BEACON_INTERVAL_INVALID;
            }
        }
        //////////////////
        if (update_mask & BSS_FIELD_MASK_HT_CAPABLE) {
            if (bss_config->ht_capable > 1) {
                return_status |= BSS_CONFIG_FAILURE_HT_CAPABLE_INVALID;
            }
        } else if(active_network_info == NULL) {
            // Adopt C default value
            bss_config->ht_capable = WLAN_DEFAULT_BSS_CONFIG_HT_CAPABLE;
            update_mask |= BSS_FIELD_MASK_HT_CAPABLE;
        }
        //////////////////
        if (update_mask & BSS_FIELD_MASK_DTIM_PERIOD) {
            if(bss_config->dtim_period == 0){
                return_status |= BSS_CONFIG_FAILURE_DTIM_PERIOD_INVALID;
            }

        } else if(active_network_info == NULL) {
            // Adopt C default value
            bss_config->dtim_period = WLAN_DEFAULT_BSS_CONFIG_DTIM_PERIOD;
            update_mask |= BSS_FIELD_MASK_DTIM_PERIOD;
        }
    }

    if (return_status == 0) {
        //---------------------------------------------------------
        // 2. Apply BSS configuration changes
        //      Now that the provided bss_config_t struct is valid, apply the changes.

        // Disable interrupts around these modifications to prevent state
        // changing out from underneath this context while the new BSS
        // configuration parameters are only partially updated.
        curr_interrupt_state = wlan_platform_intc_stop();

        if ((bss_config == NULL) || (update_mask & BSS_FIELD_MASK_BSSID)) {
            // Adopting a new BSSID. This could mean either
            //    1) Shutting the BSS down
            // or 2) Shutting the BSS down and then starting a new BSS.
            //
            // In either case, first remove any station_info structs
            // that are members of the current active_bss_info and return to
            // a NULL active_bss_info state.
            //
            // This will not result in any OTA transmissions to the stations.

            if (active_network_info != NULL) {
                //Purge all tranmissions queues
                purge_all_wireless_tx_queue();

                if ((bss_config == NULL) ||
                        ((update_mask & BSS_FIELD_MASK_BSSID) && wlan_addr_eq(bss_config->bssid, zero_addr)) ) {
                    xil_printf("Terminating BSS\n");
                }

                // Remove all associations
                next_station_info_entry = active_network_info->members.first;
                iter = active_network_info->members.length;

                while ((next_station_info_entry != NULL) && (iter-- > 0)) {
                    curr_station_info_entry = next_station_info_entry;
                    next_station_info_entry = dl_entry_next(curr_station_info_entry);

                    curr_station_info = (station_info_t*)(curr_station_info_entry->data);

                    // Remove the associations
                    network_info_remove_member(active_network_info, curr_station_info->addr);

                    time_hr_min_sec = wlan_mac_time_to_hr_min_sec(get_system_time_usec());

                    xil_printf("*%dh:%02dm:%02ds* STA %02x:%02x:%02x:%02x:%02x:%02x has disassociated\n",
                            time_hr_min_sec.hr, time_hr_min_sec.min, time_hr_min_sec.sec,
                            curr_station_info->addr[0], curr_station_info->addr[1], curr_station_info->addr[2],
                            curr_station_info->addr[3], curr_station_info->addr[4], curr_station_info->addr[5]);

                    // Lower KEEP flag so that the MAC High Framework can cleanup
                    curr_station_info->flags &= ~STATION_INFO_FLAG_KEEP;

                    // Update the hex display to show station was removed
                    wlan_platform_high_userio_disp_status(USERIO_DISP_STATUS_MEMBER_LIST_UPDATE, active_network_info->members.length);
                }

                // Remove the bss_info from the network list
                //     - When the AP "leaves" a BSS, the BSS actually no longer exists.  Therefore, it should
                //       not continue to exist in the network list.
                dl_list* network_info_list = wlan_mac_high_get_network_info_list();
                network_info_entry_t* network_entry     = wlan_mac_high_find_network_info_BSSID(active_network_info->bss_config.bssid);

                wlan_mac_high_clear_network_info(active_network_info);
                dl_entry_remove(network_info_list, (dl_entry*)network_entry);
                network_info_checkin(network_entry);

                // Set "active_network_info" to NULL
                //     - All functions must be able to handle active_network_info = NULL
                active_network_info = NULL;

                // Disable beacons immediately
                ((tx_frame_info_t*)CALC_PKT_BUF_ADDR(platform_common_dev_info.tx_pkt_buf_baseaddr, TX_PKT_BUF_BEACON))->tx_pkt_buf_state = TX_PKT_BUF_HIGH_CTRL;
                gl_beacon_txrx_config.beacon_tx_mode = NO_BEACON_TX;
                bzero(gl_beacon_txrx_config.bssid_match, MAC_ADDR_LEN);
                wlan_mac_high_config_txrx_beacon(&gl_beacon_txrx_config);

                // Set hex display to "No BSS"
                wlan_platform_high_userio_disp_status(USERIO_DISP_STATUS_MEMBER_LIST_UPDATE, 0xFF);
            }

            // (bss_config_update == NULL) is one way to remove the BSS state of the node. This operation
            // was executed just above.  Rather that continuing to check non-NULLness of bss_config_update
            // throughout the rest of this function, just re-enable interrupts and return early.

            if (bss_config == NULL) {
                wlan_platform_intc_set_state(curr_interrupt_state);
                return return_status;
            }

            // active_network_info is guaranteed to be NULL at this point in the code
            // bss_config_update is guaranteed to be non-NULL at this point in the code

            // Update BSS
            //     - BSSID must not be zero_addr (reserved address)
            if (wlan_addr_eq(bss_config->bssid, zero_addr) == 0) {
                // Stop the scan state machine if it is running
                if (wlan_mac_scan_is_scanning()) {
                    wlan_mac_scan_stop();
                }

                // Create a new network_info_t or overwrite an existing one with matching BSSID.
                //     Note:  The wildcard SSID and 0-valued channel arguments are temporary. Because
                //         of the error checking at the top of this function, the bss_config will
                //         contain a valid SSID as well as channel. These fields will be updated
                //         in step 3).
                local_network_info = wlan_mac_high_create_network_info(bss_config->bssid, "", 0);

                if (local_network_info != NULL) {
                    local_network_info->flags |= NETWORK_FLAGS_KEEP;

                    local_network_info->capabilities = (BSS_CAPABILITIES_ESS);

                    active_network_info = local_network_info;
                }

                // Set hex display
                wlan_platform_high_userio_disp_status(USERIO_DISP_STATUS_MEMBER_LIST_UPDATE, active_network_info->members.length);
            }
        }

        //---------------------------------------------------------
        // 3. Clean up
        //      Now that active_network_info has been updated, CPU_HIGH can communicate
        //      the changes to CPU_LOW so that the node is tuned to the correct channel,
        //      send beacons at the correct interval, and update the beacon
        //      template packet buffer.
        if (active_network_info != NULL) {

            if (update_mask & BSS_FIELD_MASK_CHAN) {
                active_network_info->bss_config.chan_spec = bss_config->chan_spec;
                send_channel_switch_to_low = 1;
                update_beacon_template = 1;
            }
            if (update_mask & BSS_FIELD_MASK_SSID) {
                strncpy(active_network_info->bss_config.ssid, bss_config->ssid, SSID_LEN_MAX);
                update_beacon_template = 1;
            }
            if (update_mask & BSS_FIELD_MASK_BEACON_INTERVAL) {
                active_network_info->bss_config.beacon_interval = bss_config->beacon_interval;
                memcpy(gl_beacon_txrx_config.bssid_match, active_network_info->bss_config.bssid, MAC_ADDR_LEN);
                if ((active_network_info->bss_config.beacon_interval == BEACON_INTERVAL_NO_BEACON_TX) ||
                    (active_network_info->bss_config.beacon_interval == BEACON_INTERVAL_UNKNOWN)) {
                    ((tx_frame_info_t*)CALC_PKT_BUF_ADDR(platform_common_dev_info.tx_pkt_buf_baseaddr, TX_PKT_BUF_BEACON))->tx_pkt_buf_state = TX_PKT_BUF_HIGH_CTRL;
                    gl_beacon_txrx_config.beacon_tx_mode = NO_BEACON_TX;
                } else {
                    gl_beacon_txrx_config.beacon_tx_mode = AP_BEACON_TX;
                }

                gl_beacon_txrx_config.beacon_interval_tu = active_network_info->bss_config.beacon_interval;
                gl_beacon_txrx_config.beacon_template_pkt_buf = TX_PKT_BUF_BEACON;
                update_beacon_template = 1;
                send_beacon_config_to_low = 1;
            }
            if (update_mask & BSS_FIELD_MASK_DTIM_PERIOD) {
                gl_beacon_txrx_config.dtim_period = bss_config->dtim_period;
                active_network_info->bss_config.dtim_period = bss_config->dtim_period;
                send_beacon_config_to_low = 1;
            }
            if (update_mask & BSS_FIELD_MASK_HT_CAPABLE) {
                // Changing the BSS HT_CAPABLE capabilities only affects what is advertised in
                // the BSS beacons.  It does not affect the HT capabilities of nodes in the
                // network.  It should also not change any of the default TX params since the
                // AP is still capable of sending and receiving HT packets.

                active_network_info->bss_config.ht_capable = bss_config->ht_capable;

                // Update the beacon template to match capabilities
                update_beacon_template = 1;
            }

            // Update the beacon template
            //     In the event that CPU_LOW currently has the beacon packet buffer locked,
            //     block for now until it unlocks.  This will guarantee that beacon are updated
            //     before the function returns.
            default_beacon_tx_params = wlan_mac_get_default_tx_params(mcast_mgmt);
            if (update_beacon_template) {

                while( wlan_mac_high_configure_beacon_tx_template((u8*)bcast_addr,
                                                                  wlan_mac_addr,
                                                                  active_network_info->bss_config.bssid,
                                                                  active_network_info,
                                                                  &default_beacon_tx_params,
                                                                  TX_FRAME_INFO_FLAGS_FILL_TIMESTAMP | TX_FRAME_INFO_FLAGS_WAIT_FOR_LOCK) != 0 ){}

                mgmt_tag_tim_template = NULL;
                //Add the TIM tag
                update_tim_tag_all(SCHEDULE_ID_RESERVED_MAX);
            }

            // Update the channel
            if (send_channel_switch_to_low) {
                wlan_mac_high_set_radio_channel(
                        wlan_mac_high_bss_channel_spec_to_radio_chan(active_network_info->bss_config.chan_spec));
            }

            // Update Beacon configuration
            if (send_beacon_config_to_low) {
                wlan_mac_high_config_txrx_beacon(&gl_beacon_txrx_config);
            }

            // Print new BSS information
            xil_printf("BSS Details: \n");
            xil_printf("  BSSID           : %02x-%02x-%02x-%02x-%02x-%02x\n",   active_network_info->bss_config.bssid[0],active_network_info->bss_config.bssid[1],
                                                                                active_network_info->bss_config.bssid[2],active_network_info->bss_config.bssid[3],
                                                                                active_network_info->bss_config.bssid[4],active_network_info->bss_config.bssid[5]);
            xil_printf("   SSID           : %s\n", active_network_info->bss_config.ssid);
            xil_printf("   Channel        : %d\n", wlan_mac_high_bss_channel_spec_to_radio_chan(active_network_info->bss_config.chan_spec));
            if (active_network_info->bss_config.beacon_interval == BEACON_INTERVAL_NO_BEACON_TX) {
                xil_printf("   Beacon Interval: No Beacon Tx\n");
            } else if (active_network_info->bss_config.beacon_interval == BEACON_INTERVAL_UNKNOWN) {
                xil_printf("   Beacon Interval: Unknown\n");
            } else {
                xil_printf("   Beacon Interval: %d TU (%d us)\n", active_network_info->bss_config.beacon_interval, active_network_info->bss_config.beacon_interval*1024);
            }
        }

        // Restore interrupts after all BSS changes
        wlan_platform_intc_set_state(curr_interrupt_state);
    }

    return return_status;
}



/*****************************************************************************/
/**
 * @brief Callback to handle push of User I/O button 0
 *
 * Reference implementation does nothing.
 *
 * @param None
 * @return None
 *****************************************************************************/
void button_0_press(){
    return;
}

/*****************************************************************************/
/**
 * @brief Callback to handle release of User I/O button 0
 *
 * Reference implementation does nothing.
 *
 * @param None
 * @return None
 *****************************************************************************/
void button_0_release(){
    return;
}

/*****************************************************************************/
/**
 * @brief Accessor methods for global variables
 *
 * These functions will return pointers to global variables
 *
 * @param  None
 * @return None
 *****************************************************************************/
dl_list* get_network_member_list(){
    if(active_network_info != NULL){
        return &(active_network_info->members);
    } else {
        return NULL;
    }
}

network_info_t* active_network_info_getter(){ return active_network_info; }

#if WLAN_SW_CONFIG_ENABLE_WLAN_EXP

// ****************************************************************************
// Define MAC Specific User Commands
//
// NOTE:  All User Command IDs (CMDID_*) must be a 24 bit unique number
//

//-----------------------------------------------
// MAC Specific User Commands
//
// #define CMDID_USER_<COMMAND_NAME>                       0x100000


//-----------------------------------------------
// MAC Specific User Command Parameters
//
// #define CMD_PARAM_USER_<PARAMETER_NAME>                 0x00000000



/*****************************************************************************/
/**
 * Process User Commands
 *
 * This function is part of the WLAN Exp framework and will process the framework-
 * level user commands.  This function intentionally does not implement any user
 * commands and it is left to the user to implement any needed functionality.   By
 * default, any commands not processed in this function will print an error to the
 * UART.
 *
 * @return  int              - Status of the command:
 *                                 NO_RESP_SENT - No response has been sent
 *                                 RESP_SENT    - A response has been sent
 *
 * @note    See on-line documentation for more information:
 *          https://warpproject.org/trac/wiki/802.11/wlan_exp/Extending
 *
 *****************************************************************************/
int wlan_exp_process_user_cmd(cmd_resp_hdr_t* cmd_hdr, eth_tx_queue_buffer_t* eth_tx_queue_buffer) {

    //
    // IMPORTANT ENDIAN NOTES:
    //     - command
    //         - header - Already endian swapped by the framework (safe to access directly)
    //         - args   - Must be endian swapped as necessary by code (framework does not know the contents of the command)
    //     - response
    //         - header - Will be endian swapped by the framework (safe to write directly)
    //         - args   - Must be endian swapped as necessary by code (framework does not know the contents of the response)
    //

    // Standard variables
    //
    // Used for accessing command arguments and constructing the command response header/payload
    //
    // NOTE:  Some of the standard variables below have been commented out.  This was to remove
    //     compiler warnings for "unused variables" since the default implementation is empty.  As
    //     you add commands, you should un-comment the standard variables.
    //

    u32 resp_sent = NO_RESP_SENT;
    u32 cmd_id = CMD_TO_CMDID(cmd_hdr->cmd);
#if 0
    // Segment 0 length includes a fully formed command response header
    //  because one was created with default values suitable for a responseless
    //  acknowledgment.
    cmd_resp_hdr_t* resp_hdr = (cmd_resp_hdr_t*)(eth_tx_queue_buffer->seg0
                                                 + eth_tx_queue_buffer->seg0_len
                                                 - sizeof(cmd_resp_hdr_t));

    u32* cmd_args_32 = (u32*)((u8*)cmd_hdr + sizeof(cmd_resp_hdr_t));
#endif

    switch(cmd_id){

//-----------------------------------------------------------------------------
// MAC Specific User Commands
//-----------------------------------------------------------------------------

        // Template framework for a Command
        //
        // NOTE:  The WLAN Exp framework assumes that the Over-the-Wire format of the data is
        //     big endian.  However, the node processes data using little endian.  Therefore,
        //     any data received from the host must be properly endian-swapped and similarly,
        //     any data sent to the host must be properly endian-swapped.  The built-in Xilinx
        //     functions:  Xil_Ntohl() (Network to Host) and Xil_Htonl() (Host to Network) are
        //     used for this.
        //
#if 0
        //---------------------------------------------------------------------
        case CMDID_USER_<COMMAND_NAME>: {
            // Command Description
            //
            // Message format:
            //     cmd_args_32[0:N]    Document command arguments from the host
            //
            // Response format:
            //     resp_args_32[0:M]   Document response arguments from the node
            //
            // NOTE:  Variables are declared above.
            // NOTE:  Please take care of the endianness of the arguments (see comment above)
            //

            // Variables for template command
            int status;
            u32 arg_0;
            interrupt_state_t curr_interrupt_state;

            // Initialize variables
            status = CMD_PARAM_SUCCESS;
            arg_0 = Xil_Ntohl(cmd_args_32[0]); // Swap endianness of command argument

            // Do something with argument(s)
            xil_printf("Command argument 0: 0x%08x\n", arg_0);

            // If necessary, disable interrupts before processing the command
            //  Interrupts must be disabled if the command implementation relies on any state that might
            //  change during an interrupt service routine. See the user guide for more details
            //  https://warpproject.org/trac/wiki/802.11/wlan_exp/Extending
            curr_interrupt_state = wlan_platform_intc_stop();

            // Process command arguments and generate any response payload
            //     NOTE:  If interrupts were disabled above, take care to avoid any long-running code in this
            //         block (i.e. avoid xil_printf()). When interrupts are disabled, CPU High is unable to
            //         respond to CPU Low (ie CPU High will not send / receive packets) and execute scheduled
            //         tasks, such as LTGs.

            // Re-enable interrupts before returning (only do this if wlan_platform_intc_stop() is called above)
            wlan_platform_intc_set_state(curr_interrupt_state);

            // Send response
            //   NOTE:  It is good practice to send a status as the first argument of the response.
            //       This way it is easy to determine if the other data in the response is valid.
            //       Predefined status values are:  CMD_PARAM_SUCCESS, CMD_PARAM_ERROR
            //
            wlan_exp_add_u32_resp_arg(eth_tx_queue_buffer, resp_hdr, status);
        }
        break;
#endif


        //---------------------------------------------------------------------
        default: {
            wlan_exp_printf(WLAN_EXP_PRINT_ERROR, print_type_node, "Unknown AP user command: 0x%x\n", cmd_id);
        }
        break;
    }

    return resp_sent;
}


#endif