/**
  * Functions implementing wlan scan IOCTL and firmware command APIs
  *
  * IOCTL handlers as well as command preperation and response routines
  *  for sending scan commands to the firmware.
  */
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/etherdevice.h>
#include <linux/if_arp.h>
#include <asm/unaligned.h>
#include <net/lib80211.h>

#include "host.h"
#include "decl.h"
#include "dev.h"
#include "scan.h"
#include "cmd.h"

//! Approximate amount of data needed to pass a scan result back to iwlist
#define MAX_SCAN_CELL_SIZE  (IW_EV_ADDR_LEN             \
                             + IW_ESSID_MAX_SIZE        \
                             + IW_EV_UINT_LEN           \
                             + IW_EV_FREQ_LEN           \
                             + IW_EV_QUAL_LEN           \
                             + IW_ESSID_MAX_SIZE        \
                             + IW_EV_PARAM_LEN          \
                             + 40)      /* 40 for WPAIE */

//! Memory needed to store a max sized channel List TLV for a firmware scan
#define CHAN_TLV_MAX_SIZE  (sizeof(struct mrvl_ie_header)    \
                            + (MRVDRV_MAX_CHANNELS_PER_SCAN     \
                               * sizeof(struct chanscanparamset)))

//! Memory needed to store a max number/size SSID TLV for a firmware scan
#define SSID_TLV_MAX_SIZE  (1 * sizeof(struct mrvl_ie_ssid_param_set))

//! Maximum memory needed for a cmd_ds_802_11_scan with all TLVs at max
#define MAX_SCAN_CFG_ALLOC (sizeof(struct cmd_ds_802_11_scan)   \
                            + CHAN_TLV_MAX_SIZE + SSID_TLV_MAX_SIZE)

//! The maximum number of channels the firmware can scan per command
#define MRVDRV_MAX_CHANNELS_PER_SCAN   14

/**
 * @brief Number of channels to scan per firmware scan command issuance.
 *
 *  Number restricted to prevent hitting the limit on the amount of scan data
 *  returned in a single firmware scan command.
 */
#define MRVDRV_CHANNELS_PER_SCAN_CMD   4

//! Scan time specified in the channel TLV for each channel for passive scans
#define MRVDRV_PASSIVE_SCAN_CHAN_TIME  100

//! Scan time specified in the channel TLV for each channel for active scans
#define MRVDRV_ACTIVE_SCAN_CHAN_TIME   100

#define DEFAULT_MAX_SCAN_AGE (15 * HZ)

static int lbs_ret_80211_scan(struct lbs_private *priv, unsigned long dummy,
                              struct cmd_header *resp);

/*********************************************************************/
/*                                                                   */
/*  Misc helper functions                                            */
/*                                                                   */
/*********************************************************************/

/**
 *  @brief Unsets the MSB on basic rates
 *
 * Scan through an array and unset the MSB for basic data rates.
 *
 *  @param rates     buffer of data rates
 *  @param len       size of buffer
 */
static void lbs_unset_basic_rate_flags(u8 *rates, size_t len)
{
        int i;

        for (i = 0; i < len; i++)
                rates[i] &= 0x7f;
}


static inline void clear_bss_descriptor(struct bss_descriptor *bss)
{
        /* Don't blow away ->list, just BSS data */
        memset(bss, 0, offsetof(struct bss_descriptor, list));
}

/**
 *  @brief Compare two SSIDs
 *
 *  @param ssid1    A pointer to ssid to compare
 *  @param ssid2    A pointer to ssid to compare
 *
 *  @return         0: ssid is same, otherwise is different
 */
int lbs_ssid_cmp(uint8_t *ssid1, uint8_t ssid1_len, uint8_t *ssid2,
                 uint8_t ssid2_len)
{
        if (ssid1_len != ssid2_len)
                return -1;

        return memcmp(ssid1, ssid2, ssid1_len);
}

static inline int is_same_network(struct bss_descriptor *src,
                                  struct bss_descriptor *dst)
{
        /* A network is only a duplicate if the channel, BSSID, and ESSID
         * all match.  We treat all <hidden> with the same BSSID and channel
         * as one network */
        return ((src->ssid_len == dst->ssid_len) &&
                (src->channel == dst->channel) &&
                !compare_ether_addr(src->bssid, dst->bssid) &&
                !memcmp(src->ssid, dst->ssid, src->ssid_len));
}




/*********************************************************************/
/*                                                                   */
/*  Main scanning support                                            */
/*                                                                   */
/*********************************************************************/

/**
 *  @brief Create a channel list for the driver to scan based on region info
 *
 *  Only used from lbs_scan_setup_scan_config()
 *
 *  Use the driver region/band information to construct a comprehensive list
 *    of channels to scan.  This routine is used for any scan that is not
 *    provided a specific channel list to scan.
 *
 *  @param priv          A pointer to struct lbs_private structure
 *  @param scanchanlist  Output parameter: resulting channel list to scan
 *
 *  @return              void
 */
static int lbs_scan_create_channel_list(struct lbs_private *priv,
                                        struct chanscanparamset *scanchanlist)
{
        struct region_channel *scanregion;
        struct chan_freq_power *cfp;
        int rgnidx;
        int chanidx;
        int nextchan;
        uint8_t scantype;

        chanidx = 0;

        /* Set the default scan type to the user specified type, will later
         *   be changed to passive on a per channel basis if restricted by
         *   regulatory requirements (11d or 11h)
         */
        scantype = CMD_SCAN_TYPE_ACTIVE;

        for (rgnidx = 0; rgnidx < ARRAY_SIZE(priv->region_channel); rgnidx++) {
                if (priv->enable11d && (priv->connect_status != LBS_CONNECTED)
                    && (priv->mesh_connect_status != LBS_CONNECTED)) {
                        /* Scan all the supported chan for the first scan */
                        if (!priv->universal_channel[rgnidx].valid)
                                continue;
                        scanregion = &priv->universal_channel[rgnidx];

                        /* clear the parsed_region_chan for the first scan */
                        memset(&priv->parsed_region_chan, 0x00,
                               sizeof(priv->parsed_region_chan));
                } else {
                        if (!priv->region_channel[rgnidx].valid)
                                continue;
                        scanregion = &priv->region_channel[rgnidx];
                }

                for (nextchan = 0; nextchan < scanregion->nrcfp; nextchan++, chanidx++) {
                        struct chanscanparamset *chan = &scanchanlist[chanidx];

                        cfp = scanregion->CFP + nextchan;

                        if (priv->enable11d)
                                scantype = lbs_get_scan_type_11d(cfp->channel,
                                                                 &priv->parsed_region_chan);

                        if (scanregion->band == BAND_B || scanregion->band == BAND_G)
                                chan->radiotype = CMD_SCAN_RADIO_TYPE_BG;

                        if (scantype == CMD_SCAN_TYPE_PASSIVE) {
                                chan->maxscantime = cpu_to_le16(MRVDRV_PASSIVE_SCAN_CHAN_TIME);
                                chan->chanscanmode.passivescan = 1;
                        } else {
                                chan->maxscantime = cpu_to_le16(MRVDRV_ACTIVE_SCAN_CHAN_TIME);
                                chan->chanscanmode.passivescan = 0;
                        }

                        chan->channumber = cfp->channel;
                }
        }
        return chanidx;
}

/*
 * Add SSID TLV of the form:
 *
 * TLV-ID SSID     00 00
 * length          06 00
 * ssid            4d 4e 54 45 53 54
 */
static int lbs_scan_add_ssid_tlv(struct lbs_private *priv, u8 *tlv)
{
        struct mrvl_ie_ssid_param_set *ssid_tlv = (void *)tlv;

        ssid_tlv->header.type = cpu_to_le16(TLV_TYPE_SSID);
        ssid_tlv->header.len = cpu_to_le16(priv->scan_ssid_len);
        memcpy(ssid_tlv->ssid, priv->scan_ssid, priv->scan_ssid_len);
        return sizeof(ssid_tlv->header) + priv->scan_ssid_len;
}

/*
 * Add CHANLIST TLV of the form
 *
 * TLV-ID CHANLIST 01 01
 * length          5b 00
 * channel 1       00 01 00 00 00 64 00
 *   radio type    00
 *   channel          01
 *   scan type           00
 *   min scan time          00 00
 *   max scan time                64 00
 * channel 2       00 02 00 00 00 64 00
 * channel 3       00 03 00 00 00 64 00
 * channel 4       00 04 00 00 00 64 00
 * channel 5       00 05 00 00 00 64 00
 * channel 6       00 06 00 00 00 64 00
 * channel 7       00 07 00 00 00 64 00
 * channel 8       00 08 00 00 00 64 00
 * channel 9       00 09 00 00 00 64 00
 * channel 10      00 0a 00 00 00 64 00
 * channel 11      00 0b 00 00 00 64 00
 * channel 12      00 0c 00 00 00 64 00
 * channel 13      00 0d 00 00 00 64 00
 *
 */
static int lbs_scan_add_chanlist_tlv(uint8_t *tlv,
                                     struct chanscanparamset *chan_list,
                                     int chan_count)
{
        size_t size = sizeof(struct chanscanparamset) *chan_count;
        struct mrvl_ie_chanlist_param_set *chan_tlv = (void *)tlv;

        chan_tlv->header.type = cpu_to_le16(TLV_TYPE_CHANLIST);
        memcpy(chan_tlv->chanscanparam, chan_list, size);
        chan_tlv->header.len = cpu_to_le16(size);
        return sizeof(chan_tlv->header) + size;
}

/*
 * Add RATES TLV of the form
 *
 * TLV-ID RATES    01 00
 * length          0e 00
 * rates           82 84 8b 96 0c 12 18 24 30 48 60 6c
 *
 * The rates are in lbs_bg_rates[], but for the 802.11b
 * rates the high bit isn't set.
 */
static int lbs_scan_add_rates_tlv(uint8_t *tlv)
{
        int i;
        struct mrvl_ie_rates_param_set *rate_tlv = (void *)tlv;

        rate_tlv->header.type = cpu_to_le16(TLV_TYPE_RATES);
        tlv += sizeof(rate_tlv->header);
        for (i = 0; i < MAX_RATES; i++) {
                *tlv = lbs_bg_rates[i];
                if (*tlv == 0)
                        break;
                /* This code makes sure that the 802.11b rates (1 MBit/s, 2
                   MBit/s, 5.5 MBit/s and 11 MBit/s get's the high bit set.
                   Note that the values are MBit/s * 2, to mark them as
                   basic rates so that the firmware likes it better */
                if (*tlv == 0x02 || *tlv == 0x04 ||
                    *tlv == 0x0b || *tlv == 0x16)
                        *tlv |= 0x80;
                tlv++;
        }
        rate_tlv->header.len = cpu_to_le16(i);
        return sizeof(rate_tlv->header) + i;
}

/*
 * Generate the CMD_802_11_SCAN command with the proper tlv
 * for a bunch of channels.
 */
static int lbs_do_scan(struct lbs_private *priv, uint8_t bsstype,
                       struct chanscanparamset *chan_list, int chan_count)
{
        int ret = -ENOMEM;
        struct cmd_ds_802_11_scan *scan_cmd;
        uint8_t *tlv;   /* pointer into our current, growing TLV storage area */

        lbs_deb_enter_args(LBS_DEB_SCAN, "bsstype %d, chanlist[].chan %d, chan_count %d",
                bsstype, chan_list ? chan_list[0].channumber : -1,
                chan_count);

        /* create the fixed part for scan command */
        scan_cmd = kzalloc(MAX_SCAN_CFG_ALLOC, GFP_KERNEL);
        if (scan_cmd == NULL)
                goto out;

        tlv = scan_cmd->tlvbuffer;
        /* TODO: do we need to scan for a specific BSSID?
        memcpy(scan_cmd->bssid, priv->scan_bssid, ETH_ALEN); */
        scan_cmd->bsstype = bsstype;

        /* add TLVs */
        if (priv->scan_ssid_len)
                tlv += lbs_scan_add_ssid_tlv(priv, tlv);
        if (chan_list && chan_count)
                tlv += lbs_scan_add_chanlist_tlv(tlv, chan_list, chan_count);
        tlv += lbs_scan_add_rates_tlv(tlv);

        /* This is the final data we are about to send */
        scan_cmd->hdr.size = cpu_to_le16(tlv - (uint8_t *)scan_cmd);
        lbs_deb_hex(LBS_DEB_SCAN, "SCAN_CMD", (void *)scan_cmd,
                    sizeof(*scan_cmd));
        lbs_deb_hex(LBS_DEB_SCAN, "SCAN_TLV", scan_cmd->tlvbuffer,
                    tlv - scan_cmd->tlvbuffer);

        ret = __lbs_cmd(priv, CMD_802_11_SCAN, &scan_cmd->hdr,
                        le16_to_cpu(scan_cmd->hdr.size),
                        lbs_ret_80211_scan, 0);

out:
        kfree(scan_cmd);
        lbs_deb_leave_args(LBS_DEB_SCAN, "ret %d", ret);
        return ret;
}

/**
 *  @brief Internal function used to start a scan based on an input config
 *
 *  Use the input user scan configuration information when provided in
 *    order to send the appropriate scan commands to firmware to populate or
 *    update the internal driver scan table
 *
 *  @param priv          A pointer to struct lbs_private structure
 *  @param full_scan     Do a full-scan (blocking)
 *
 *  @return              0 or < 0 if error
 */
int lbs_scan_networks(struct lbs_private *priv, int full_scan)
{
        int ret = -ENOMEM;
        struct chanscanparamset *chan_list;
        struct chanscanparamset *curr_chans;
        int chan_count;
        uint8_t bsstype = CMD_BSS_TYPE_ANY;
        int numchannels = MRVDRV_CHANNELS_PER_SCAN_CMD;
        union iwreq_data wrqu;
#ifdef CONFIG_LIBERTAS_DEBUG
        struct bss_descriptor *iter;
        int i = 0;
        DECLARE_SSID_BUF(ssid);
#endif

        lbs_deb_enter_args(LBS_DEB_SCAN, "full_scan %d", full_scan);

        /* Cancel any partial outstanding partial scans if this scan
         * is a full scan.
         */
        if (full_scan && delayed_work_pending(&priv->scan_work))
                cancel_delayed_work(&priv->scan_work);

        /* User-specified bsstype or channel list
        TODO: this can be implemented if some user-space application
        need the feature. Formerly, it was accessible from debugfs,
        but then nowhere used.
        if (user_cfg) {
                if (user_cfg->bsstype)
                bsstype = user_cfg->bsstype;
        } */

        lbs_deb_scan("numchannels %d, bsstype %d\n", numchannels, bsstype);

        /* Create list of channels to scan */
        chan_list = kzalloc(sizeof(struct chanscanparamset) *
                            LBS_IOCTL_USER_SCAN_CHAN_MAX, GFP_KERNEL);
        if (!chan_list) {
                lbs_pr_alert("SCAN: chan_list empty\n");
                goto out;
        }

        /* We want to scan all channels */
        chan_count = lbs_scan_create_channel_list(priv, chan_list);

        netif_stop_queue(priv->dev);
        netif_carrier_off(priv->dev);
        if (priv->mesh_dev) {
                netif_stop_queue(priv->mesh_dev);
                netif_carrier_off(priv->mesh_dev);
        }

        /* Prepare to continue an interrupted scan */
        lbs_deb_scan("chan_count %d, scan_channel %d\n",
                     chan_count, priv->scan_channel);
        curr_chans = chan_list;
        /* advance channel list by already-scanned-channels */
        if (priv->scan_channel > 0) {
                curr_chans += priv->scan_channel;
                chan_count -= priv->scan_channel;
        }

        /* Send scan command(s)
         * numchannels contains the number of channels we should maximally scan
         * chan_count is the total number of channels to scan
         */

        while (chan_count) {
                int to_scan = min(numchannels, chan_count);
                lbs_deb_scan("scanning %d of %d channels\n",
                             to_scan, chan_count);
                ret = lbs_do_scan(priv, bsstype, curr_chans,
                                  to_scan);
                if (ret) {
                        lbs_pr_err("SCAN_CMD failed\n");
                        goto out2;
                }
                curr_chans += to_scan;
                chan_count -= to_scan;

                /* somehow schedule the next part of the scan */
                if (chan_count && !full_scan &&
                    !priv->surpriseremoved) {
                        /* -1 marks just that we're currently scanning */
                        if (priv->scan_channel < 0)
                                priv->scan_channel = to_scan;
                        else
                                priv->scan_channel += to_scan;
                        cancel_delayed_work(&priv->scan_work);
                        queue_delayed_work(priv->work_thread, &priv->scan_work,
                                           msecs_to_jiffies(300));
                        /* skip over GIWSCAN event */
                        goto out;
                }

        }
        memset(&wrqu, 0, sizeof(union iwreq_data));
        wireless_send_event(priv->dev, SIOCGIWSCAN, &wrqu, NULL);

#ifdef CONFIG_LIBERTAS_DEBUG
        /* Dump the scan table */
        mutex_lock(&priv->lock);
        lbs_deb_scan("scan table:\n");
        list_for_each_entry(iter, &priv->network_list, list)
                lbs_deb_scan("%02d: BSSID %pM, RSSI %d, SSID '%s'\n",
                             i++, iter->bssid, iter->rssi,
                             print_ssid(ssid, iter->ssid, iter->ssid_len));
        mutex_unlock(&priv->lock);
#endif

out2:
        priv->scan_channel = 0;

out:
        if (priv->connect_status == LBS_CONNECTED) {
                netif_carrier_on(priv->dev);
                if (!priv->tx_pending_len)
                        netif_wake_queue(priv->dev);
        }
        if (priv->mesh_dev && (priv->mesh_connect_status == LBS_CONNECTED)) {
                netif_carrier_on(priv->mesh_dev);
                if (!priv->tx_pending_len)
                        netif_wake_queue(priv->mesh_dev);
        }
        kfree(chan_list);

        lbs_deb_leave_args(LBS_DEB_SCAN, "ret %d", ret);
        return ret;
}

void lbs_scan_worker(struct work_struct *work)
{
        struct lbs_private *priv =
                container_of(work, struct lbs_private, scan_work.work);

        lbs_deb_enter(LBS_DEB_SCAN);
        lbs_scan_networks(priv, 0);
        lbs_deb_leave(LBS_DEB_SCAN);
}


/*********************************************************************/
/*                                                                   */
/*  Result interpretation                                            */
/*                                                                   */
/*********************************************************************/

/**
 *  @brief Interpret a BSS scan response returned from the firmware
 *
 *  Parse the various fixed fields and IEs passed back for a a BSS probe
 *  response or beacon from the scan command.  Record information as needed
 *  in the scan table struct bss_descriptor for that entry.
 *
 *  @param bss  Output parameter: Pointer to the BSS Entry
 *
 *  @return             0 or -1
 */
static int lbs_process_bss(struct bss_descriptor *bss,
                           uint8_t **pbeaconinfo, int *bytesleft)
{
        struct ieee_ie_fh_param_set *fh;
        struct ieee_ie_ds_param_set *ds;
        struct ieee_ie_cf_param_set *cf;
        struct ieee_ie_ibss_param_set *ibss;
        DECLARE_SSID_BUF(ssid);
        struct ieee_ie_country_info_set *pcountryinfo;
        uint8_t *pos, *end, *p;
        uint8_t n_ex_rates = 0, got_basic_rates = 0, n_basic_rates = 0;
        uint16_t beaconsize = 0;
        int ret;

        lbs_deb_enter(LBS_DEB_SCAN);

        if (*bytesleft >= sizeof(beaconsize)) {
                /* Extract & convert beacon size from the command buffer */
                beaconsize = get_unaligned_le16(*pbeaconinfo);
                *bytesleft -= sizeof(beaconsize);
                *pbeaconinfo += sizeof(beaconsize);
        }

        if (beaconsize == 0 || beaconsize > *bytesleft) {
                *pbeaconinfo += *bytesleft;
                *bytesleft = 0;
                ret = -1;
                goto done;
        }

        /* Initialize the current working beacon pointer for this BSS iteration */
        pos = *pbeaconinfo;
        end = pos + beaconsize;

        /* Advance the return beacon pointer past the current beacon */
        *pbeaconinfo += beaconsize;
        *bytesleft -= beaconsize;

        memcpy(bss->bssid, pos, ETH_ALEN);
        lbs_deb_scan("process_bss: BSSID %pM\n", bss->bssid);
        pos += ETH_ALEN;

        if ((end - pos) < 12) {
                lbs_deb_scan("process_bss: Not enough bytes left\n");
                ret = -1;
                goto done;
        }

        /*
         * next 4 fields are RSSI, time stamp, beacon interval,
         *   and capability information
         */

        /* RSSI is 1 byte long */
        bss->rssi = *pos;
        lbs_deb_scan("process_bss: RSSI %d\n", *pos);
        pos++;

        /* time stamp is 8 bytes long */
        pos += 8;

        /* beacon interval is 2 bytes long */
        bss->beaconperiod = get_unaligned_le16(pos);
        pos += 2;

        /* capability information is 2 bytes long */
        bss->capability = get_unaligned_le16(pos);
        lbs_deb_scan("process_bss: capabilities 0x%04x\n", bss->capability);
        pos += 2;

        if (bss->capability & WLAN_CAPABILITY_PRIVACY)
                lbs_deb_scan("process_bss: WEP enabled\n");
        if (bss->capability & WLAN_CAPABILITY_IBSS)
                bss->mode = IW_MODE_ADHOC;
        else
                bss->mode = IW_MODE_INFRA;

        /* rest of the current buffer are IE's */
        lbs_deb_scan("process_bss: IE len %zd\n", end - pos);
        lbs_deb_hex(LBS_DEB_SCAN, "process_bss: IE info", pos, end - pos);

        /* process variable IE */
        while (pos <= end - 2) {
                if (pos + pos[1] > end) {
                        lbs_deb_scan("process_bss: error in processing IE, "
                                     "bytes left < IE length\n");
                        break;
                }

                switch (pos[0]) {
                case WLAN_EID_SSID:
                        bss->ssid_len = min_t(int, IEEE80211_MAX_SSID_LEN, pos[1]);
                        memcpy(bss->ssid, pos + 2, bss->ssid_len);
                        lbs_deb_scan("got SSID IE: '%s', len %u\n",
                                     print_ssid(ssid, bss->ssid, bss->ssid_len),
                                     bss->ssid_len);
                        break;

                case WLAN_EID_SUPP_RATES:
                        n_basic_rates = min_t(uint8_t, MAX_RATES, pos[1]);
                        memcpy(bss->rates, pos + 2, n_basic_rates);
                        got_basic_rates = 1;
                        lbs_deb_scan("got RATES IE\n");
                        break;

                case WLAN_EID_FH_PARAMS:
                        fh = (struct ieee_ie_fh_param_set *) pos;
                        memcpy(&bss->phy.fh, fh, sizeof(*fh));
                        lbs_deb_scan("got FH IE\n");
                        break;

                case WLAN_EID_DS_PARAMS:
                        ds = (struct ieee_ie_ds_param_set *) pos;
                        bss->channel = ds->channel;
                        memcpy(&bss->phy.ds, ds, sizeof(*ds));
                        lbs_deb_scan("got DS IE, channel %d\n", bss->channel);
                        break;

                case WLAN_EID_CF_PARAMS:
                        cf = (struct ieee_ie_cf_param_set *) pos;
                        memcpy(&bss->ss.cf, cf, sizeof(*cf));
                        lbs_deb_scan("got CF IE\n");
                        break;

                case WLAN_EID_IBSS_PARAMS:
                        ibss = (struct ieee_ie_ibss_param_set *) pos;
                        bss->atimwindow = ibss->atimwindow;
                        memcpy(&bss->ss.ibss, ibss, sizeof(*ibss));
                        lbs_deb_scan("got IBSS IE\n");
                        break;

                case WLAN_EID_COUNTRY:
                        pcountryinfo = (struct ieee_ie_country_info_set *) pos;
                        lbs_deb_scan("got COUNTRY IE\n");
                        if (pcountryinfo->header.len < sizeof(pcountryinfo->countrycode)
                            || pcountryinfo->header.len > 254) {
                                lbs_deb_scan("%s: 11D- Err CountryInfo len %d, min %zd, max 254\n",
                                             __func__,
                                             pcountryinfo->header.len,
                                             sizeof(pcountryinfo->countrycode));
                                ret = -1;
                                goto done;
                        }

                        memcpy(&bss->countryinfo, pcountryinfo,
                                pcountryinfo->header.len + 2);
                        lbs_deb_hex(LBS_DEB_SCAN, "process_bss: 11d countryinfo",
                                    (uint8_t *) pcountryinfo,
                                    (int) (pcountryinfo->header.len + 2));
                        break;

                case WLAN_EID_EXT_SUPP_RATES:
                        /* only process extended supported rate if data rate is
                         * already found. Data rate IE should come before
                         * extended supported rate IE
                         */
                        lbs_deb_scan("got RATESEX IE\n");
                        if (!got_basic_rates) {
                                lbs_deb_scan("... but ignoring it\n");
                                break;
                        }

                        n_ex_rates = pos[1];
                        if (n_basic_rates + n_ex_rates > MAX_RATES)
                                n_ex_rates = MAX_RATES - n_basic_rates;

                        p = bss->rates + n_basic_rates;
                        memcpy(p, pos + 2, n_ex_rates);
                        break;

                case WLAN_EID_GENERIC:
                        if (pos[1] >= 4 &&
                            pos[2] == 0x00 && pos[3] == 0x50 &&
                            pos[4] == 0xf2 && pos[5] == 0x01) {
                                bss->wpa_ie_len = min(pos[1] + 2, MAX_WPA_IE_LEN);
                                memcpy(bss->wpa_ie, pos, bss->wpa_ie_len);
                                lbs_deb_scan("got WPA IE\n");
                                lbs_deb_hex(LBS_DEB_SCAN, "WPA IE", bss->wpa_ie,
                                            bss->wpa_ie_len);
                        } else if (pos[1] >= MARVELL_MESH_IE_LENGTH &&
                                   pos[2] == 0x00 && pos[3] == 0x50 &&
                                   pos[4] == 0x43 && pos[5] == 0x04) {
                                lbs_deb_scan("got mesh IE\n");
                                bss->mesh = 1;
                        } else {
                                lbs_deb_scan("got generic IE: %02x:%02x:%02x:%02x, len %d\n",
                                        pos[2], pos[3],
                                        pos[4], pos[5],
                                        pos[1]);
                        }
                        break;

                case WLAN_EID_RSN:
                        lbs_deb_scan("got RSN IE\n");
                        bss->rsn_ie_len = min(pos[1] + 2, MAX_WPA_IE_LEN);
                        memcpy(bss->rsn_ie, pos, bss->rsn_ie_len);
                        lbs_deb_hex(LBS_DEB_SCAN, "process_bss: RSN_IE",
                                    bss->rsn_ie, bss->rsn_ie_len);
                        break;

                default:
                        lbs_deb_scan("got IE 0x%04x, len %d\n",
                                     pos[0], pos[1]);
                        break;
                }

                pos += pos[1] + 2;
        }

        /* Timestamp */
        bss->last_scanned = jiffies;
        lbs_unset_basic_rate_flags(bss->rates, sizeof(bss->rates));

        ret = 0;

done:
        lbs_deb_leave_args(LBS_DEB_SCAN, "ret %d", ret);
        return ret;
}

/**
 *  @brief Send a scan command for all available channels filtered on a spec
 *
 *  Used in association code and from debugfs
 *
 *  @param priv             A pointer to struct lbs_private structure
 *  @param ssid             A pointer to the SSID to scan for
 *  @param ssid_len         Length of the SSID
 *
 *  @return                0-success, otherwise fail
 */
int lbs_send_specific_ssid_scan(struct lbs_private *priv, uint8_t *ssid,
                                uint8_t ssid_len)
{
        DECLARE_SSID_BUF(ssid_buf);
        int ret = 0;

        lbs_deb_enter_args(LBS_DEB_SCAN, "SSID '%s'\n",
                           print_ssid(ssid_buf, ssid, ssid_len));

        if (!ssid_len)
                goto out;

        memcpy(priv->scan_ssid, ssid, ssid_len);
        priv->scan_ssid_len = ssid_len;

        lbs_scan_networks(priv, 1);
        if (priv->surpriseremoved) {
                ret = -1;
                goto out;
        }

out:
        lbs_deb_leave_args(LBS_DEB_SCAN, "ret %d", ret);
        return ret;
}




/*********************************************************************/
/*                                                                   */
/*  Support for Wireless Extensions                                  */
/*                                                                   */
/*********************************************************************/


#define MAX_CUSTOM_LEN 64

static inline char *lbs_translate_scan(struct lbs_private *priv,
                                            struct iw_request_info *info,
                                            char *start, char *stop,
                                            struct bss_descriptor *bss)
{
        struct chan_freq_power *cfp;
        char *current_val;      /* For rates */
        struct iw_event iwe;    /* Temporary buffer */
        int j;
#define PERFECT_RSSI ((uint8_t)50)
#define WORST_RSSI   ((uint8_t)0)
#define RSSI_DIFF    ((uint8_t)(PERFECT_RSSI - WORST_RSSI))
        uint8_t rssi;

        lbs_deb_enter(LBS_DEB_SCAN);

        cfp = lbs_find_cfp_by_band_and_channel(priv, 0, bss->channel);
        if (!cfp) {
                lbs_deb_scan("Invalid channel number %d\n", bss->channel);
                start = NULL;
                goto out;
        }

        /* First entry *MUST* be the BSSID */
        iwe.cmd = SIOCGIWAP;
        iwe.u.ap_addr.sa_family = ARPHRD_ETHER;
        memcpy(iwe.u.ap_addr.sa_data, &bss->bssid, ETH_ALEN);
        start = iwe_stream_add_event(info, start, stop, &iwe, IW_EV_ADDR_LEN);

        /* SSID */
        iwe.cmd = SIOCGIWESSID;
        iwe.u.data.flags = 1;
        iwe.u.data.length = min((uint32_t) bss->ssid_len, (uint32_t) IW_ESSID_MAX_SIZE);
        start = iwe_stream_add_point(info, start, stop, &iwe, bss->ssid);

        /* Mode */
        iwe.cmd = SIOCGIWMODE;
        iwe.u.mode = bss->mode;
        start = iwe_stream_add_event(info, start, stop, &iwe, IW_EV_UINT_LEN);

        /* Frequency */
        iwe.cmd = SIOCGIWFREQ;
        iwe.u.freq.m = (long)cfp->freq * 100000;
        iwe.u.freq.e = 1;
        start = iwe_stream_add_event(info, start, stop, &iwe, IW_EV_FREQ_LEN);

        /* Add quality statistics */
        iwe.cmd = IWEVQUAL;
        iwe.u.qual.updated = IW_QUAL_ALL_UPDATED;
        iwe.u.qual.level = SCAN_RSSI(bss->rssi);

        rssi = iwe.u.qual.level - MRVDRV_NF_DEFAULT_SCAN_VALUE;
        iwe.u.qual.qual =
                (100 * RSSI_DIFF * RSSI_DIFF - (PERFECT_RSSI - rssi) *
                 (15 * (RSSI_DIFF) + 62 * (PERFECT_RSSI - rssi))) /
                (RSSI_DIFF * RSSI_DIFF);
        if (iwe.u.qual.qual > 100)
                iwe.u.qual.qual = 100;

        if (priv->NF[TYPE_BEACON][TYPE_NOAVG] == 0) {
                iwe.u.qual.noise = MRVDRV_NF_DEFAULT_SCAN_VALUE;
        } else {
                iwe.u.qual.noise = CAL_NF(priv->NF[TYPE_BEACON][TYPE_NOAVG]);
        }

        /* Locally created ad-hoc BSSs won't have beacons if this is the
         * only station in the adhoc network; so get signal strength
         * from receive statistics.
         */
        if ((priv->mode == IW_MODE_ADHOC) && priv->adhoccreate
            && !lbs_ssid_cmp(priv->curbssparams.ssid,
                             priv->curbssparams.ssid_len,
                             bss->ssid, bss->ssid_len)) {
                int snr, nf;
                snr = priv->SNR[TYPE_RXPD][TYPE_AVG] / AVG_SCALE;
                nf = priv->NF[TYPE_RXPD][TYPE_AVG] / AVG_SCALE;
                iwe.u.qual.level = CAL_RSSI(snr, nf);
        }
        start = iwe_stream_add_event(info, start, stop, &iwe, IW_EV_QUAL_LEN);

        /* Add encryption capability */
        iwe.cmd = SIOCGIWENCODE;
        if (bss->capability & WLAN_CAPABILITY_PRIVACY) {
                iwe.u.data.flags = IW_ENCODE_ENABLED | IW_ENCODE_NOKEY;
        } else {
                iwe.u.data.flags = IW_ENCODE_DISABLED;
        }
        iwe.u.data.length = 0;
        start = iwe_stream_add_point(info, start, stop, &iwe, bss->ssid);

        current_val = start + iwe_stream_lcp_len(info);

        iwe.cmd = SIOCGIWRATE;
        iwe.u.bitrate.fixed = 0;
        iwe.u.bitrate.disabled = 0;
        iwe.u.bitrate.value = 0;

        for (j = 0; j < ARRAY_SIZE(bss->rates) && bss->rates[j]; j++) {
                /* Bit rate given in 500 kb/s units */
                iwe.u.bitrate.value = bss->rates[j] * 500000;
                current_val = iwe_stream_add_value(info, start, current_val,
                                                   stop, &iwe, IW_EV_PARAM_LEN);
        }
        if ((bss->mode == IW_MODE_ADHOC) && priv->adhoccreate
            && !lbs_ssid_cmp(priv->curbssparams.ssid,
                             priv->curbssparams.ssid_len,
                             bss->ssid, bss->ssid_len)) {
                iwe.u.bitrate.value = 22 * 500000;
                current_val = iwe_stream_add_value(info, start, current_val,
                                                   stop, &iwe, IW_EV_PARAM_LEN);
        }
        /* Check if we added any event */
        if ((current_val - start) > iwe_stream_lcp_len(info))
                start = current_val;

        memset(&iwe, 0, sizeof(iwe));
        if (bss->wpa_ie_len) {
                char buf[MAX_WPA_IE_LEN];
                memcpy(buf, bss->wpa_ie, bss->wpa_ie_len);
                iwe.cmd = IWEVGENIE;
                iwe.u.data.length = bss->wpa_ie_len;
                start = iwe_stream_add_point(info, start, stop, &iwe, buf);
        }

        memset(&iwe, 0, sizeof(iwe));
        if (bss->rsn_ie_len) {
                char buf[MAX_WPA_IE_LEN];
                memcpy(buf, bss->rsn_ie, bss->rsn_ie_len);
                iwe.cmd = IWEVGENIE;
                iwe.u.data.length = bss->rsn_ie_len;
                start = iwe_stream_add_point(info, start, stop, &iwe, buf);
        }

        if (bss->mesh) {
                char custom[MAX_CUSTOM_LEN];
                char *p = custom;

                iwe.cmd = IWEVCUSTOM;
                p += snprintf(p, MAX_CUSTOM_LEN, "mesh-type: olpc");
                iwe.u.data.length = p - custom;
                if (iwe.u.data.length)
                        start = iwe_stream_add_point(info, start, stop,
                                                     &iwe, custom);
        }

out:
        lbs_deb_leave_args(LBS_DEB_SCAN, "start %p", start);
        return start;
}


/**
 *  @brief Handle Scan Network ioctl
 *
 *  @param dev          A pointer to net_device structure
 *  @param info         A pointer to iw_request_info structure
 *  @param vwrq         A pointer to iw_param structure
 *  @param extra        A pointer to extra data buf
 *
 *  @return             0 --success, otherwise fail
 */
int lbs_set_scan(struct net_device *dev, struct iw_request_info *info,
                 union iwreq_data *wrqu, char *extra)
{
        DECLARE_SSID_BUF(ssid);
        struct lbs_private *priv = dev->ml_priv;
        int ret = 0;

        lbs_deb_enter(LBS_DEB_WEXT);

        if (!priv->radio_on) {
                ret = -EINVAL;
                goto out;
        }

        if (!netif_running(dev)) {
                ret = -ENETDOWN;
                goto out;
        }

        /* mac80211 does this:
        struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
        if (sdata->type != IEEE80211_IF_TYPE_xxx) {
                ret = -EOPNOTSUPP;
                goto out;
        }
        */

        if (wrqu->data.length == sizeof(struct iw_scan_req) &&
            wrqu->data.flags & IW_SCAN_THIS_ESSID) {
                struct iw_scan_req *req = (struct iw_scan_req *)extra;
                priv->scan_ssid_len = req->essid_len;
                memcpy(priv->scan_ssid, req->essid, priv->scan_ssid_len);
                lbs_deb_wext("set_scan, essid '%s'\n",
                        print_ssid(ssid, priv->scan_ssid, priv->scan_ssid_len));
        } else {
                priv->scan_ssid_len = 0;
        }

        if (!delayed_work_pending(&priv->scan_work))
                queue_delayed_work(priv->work_thread, &priv->scan_work,
                                   msecs_to_jiffies(50));
        /* set marker that currently a scan is taking place */
        priv->scan_channel = -1;

        if (priv->surpriseremoved)
                ret = -EIO;

out:
        lbs_deb_leave_args(LBS_DEB_WEXT, "ret %d", ret);
        return ret;
}


/**
 *  @brief  Handle Retrieve scan table ioctl
 *
 *  @param dev          A pointer to net_device structure

 *  @param info         A pointer to iw_request_info structure
 *  @param dwrq         A pointer to iw_point structure
 *  @param extra        A pointer to extra data buf
 *
 *  @return             0 --success, otherwise fail
 */
int lbs_get_scan(struct net_device *dev, struct iw_request_info *info,
                 struct iw_point *dwrq, char *extra)
{
#define SCAN_ITEM_SIZE 128
        struct lbs_private *priv = dev->ml_priv;
        int err = 0;
        char *ev = extra;
        char *stop = ev + dwrq->length;
        struct bss_descriptor *iter_bss;
        struct bss_descriptor *safe;

        lbs_deb_enter(LBS_DEB_WEXT);

        /* iwlist should wait until the current scan is finished */
        if (priv->scan_channel)
                return -EAGAIN;

        /* Update RSSI if current BSS is a locally created ad-hoc BSS */
        if ((priv->mode == IW_MODE_ADHOC) && priv->adhoccreate)
                lbs_prepare_and_send_command(priv, CMD_802_11_RSSI, 0,
                                             CMD_OPTION_WAITFORRSP, 0, NULL);

        mutex_lock(&priv->lock);
        list_for_each_entry_safe (iter_bss, safe, &priv->network_list, list) {
                char *next_ev;
                unsigned long stale_time;

                if (stop - ev < SCAN_ITEM_SIZE) {
                        err = -E2BIG;
                        break;
                }

                /* For mesh device, list only mesh networks */
                if (dev == priv->mesh_dev && !iter_bss->mesh)
                        continue;

                /* Prune old an old scan result */
                stale_time = iter_bss->last_scanned + DEFAULT_MAX_SCAN_AGE;
                if (time_after(jiffies, stale_time)) {
                        list_move_tail(&iter_bss->list, &priv->network_free_list);
                        clear_bss_descriptor(iter_bss);
                        continue;
                }

                /* Translate to WE format this entry */
                next_ev = lbs_translate_scan(priv, info, ev, stop, iter_bss);
                if (next_ev == NULL)
                        continue;
                ev = next_ev;
        }
        mutex_unlock(&priv->lock);

        dwrq->length = (ev - extra);
        dwrq->flags = 0;

        lbs_deb_leave_args(LBS_DEB_WEXT, "ret %d", err);
        return err;
}




/*********************************************************************/
/*                                                                   */
/*  Command execution                                                */
/*                                                                   */
/*********************************************************************/


/**
 *  @brief This function handles the command response of scan
 *
 *  Called from handle_cmd_response() in cmdrespc.
 *
 *   The response buffer for the scan command has the following
 *      memory layout:
 *
 *     .-----------------------------------------------------------.
 *     |  header (4 * sizeof(u16)):  Standard command response hdr |
 *     .-----------------------------------------------------------.
 *     |  bufsize (u16) : sizeof the BSS Description data          |
 *     .-----------------------------------------------------------.
 *     |  NumOfSet (u8) : Number of BSS Descs returned             |
 *     .-----------------------------------------------------------.
 *     |  BSSDescription data (variable, size given in bufsize)    |
 *     .-----------------------------------------------------------.
 *     |  TLV data (variable, size calculated using header->size,  |
 *     |            bufsize and sizeof the fixed fields above)     |
 *     .-----------------------------------------------------------.
 *
 *  @param priv    A pointer to struct lbs_private structure
 *  @param resp    A pointer to cmd_ds_command
 *
 *  @return        0 or -1
 */
static int lbs_ret_80211_scan(struct lbs_private *priv, unsigned long dummy,
                              struct cmd_header *resp)
{
        struct cmd_ds_802_11_scan_rsp *scanresp = (void *)resp;
        struct bss_descriptor *iter_bss;
        struct bss_descriptor *safe;
        uint8_t *bssinfo;
        uint16_t scanrespsize;
        int bytesleft;
        int idx;
        int tlvbufsize;
        int ret;

        lbs_deb_enter(LBS_DEB_SCAN);

        /* Prune old entries from scan table */
        list_for_each_entry_safe (iter_bss, safe, &priv->network_list, list) {
                unsigned long stale_time = iter_bss->last_scanned + DEFAULT_MAX_SCAN_AGE;
                if (time_before(jiffies, stale_time))
                        continue;
                list_move_tail (&iter_bss->list, &priv->network_free_list);
                clear_bss_descriptor(iter_bss);
        }

        if (scanresp->nr_sets > MAX_NETWORK_COUNT) {
                lbs_deb_scan("SCAN_RESP: too many scan results (%d, max %d)\n",
                             scanresp->nr_sets, MAX_NETWORK_COUNT);
                ret = -1;
                goto done;
        }

        bytesleft = get_unaligned_le16(&scanresp->bssdescriptsize);
        lbs_deb_scan("SCAN_RESP: bssdescriptsize %d\n", bytesleft);

        scanrespsize = le16_to_cpu(resp->size);
        lbs_deb_scan("SCAN_RESP: scan results %d\n", scanresp->nr_sets);

        bssinfo = scanresp->bssdesc_and_tlvbuffer;

        /* The size of the TLV buffer is equal to the entire command response
         *   size (scanrespsize) minus the fixed fields (sizeof()'s), the
         *   BSS Descriptions (bssdescriptsize as bytesLef) and the command
         *   response header (S_DS_GEN)
         */
        tlvbufsize = scanrespsize - (bytesleft + sizeof(scanresp->bssdescriptsize)
                                     + sizeof(scanresp->nr_sets)
                                     + S_DS_GEN);

        /*
         *  Process each scan response returned (scanresp->nr_sets). Save
         *    the information in the newbssentry and then insert into the
         *    driver scan table either as an update to an existing entry
         *    or as an addition at the end of the table
         */
        for (idx = 0; idx < scanresp->nr_sets && bytesleft; idx++) {
                struct bss_descriptor new;
                struct bss_descriptor *found = NULL;
                struct bss_descriptor *oldest = NULL;

                /* Process the data fields and IEs returned for this BSS */
                memset(&new, 0, sizeof (struct bss_descriptor));
                if (lbs_process_bss(&new, &bssinfo, &bytesleft) != 0) {
                        /* error parsing the scan response, skipped */
                        lbs_deb_scan("SCAN_RESP: process_bss returned ERROR\n");
                        continue;
                }

                /* Try to find this bss in the scan table */
                list_for_each_entry (iter_bss, &priv->network_list, list) {
                        if (is_same_network(iter_bss, &new)) {
                                found = iter_bss;
                                break;
                        }

                        if ((oldest == NULL) ||
                            (iter_bss->last_scanned < oldest->last_scanned))
                                oldest = iter_bss;
                }

                if (found) {
                        /* found, clear it */
                        clear_bss_descriptor(found);
                } else if (!list_empty(&priv->network_free_list)) {
                        /* Pull one from the free list */
                        found = list_entry(priv->network_free_list.next,
                                           struct bss_descriptor, list);
                        list_move_tail(&found->list, &priv->network_list);
                } else if (oldest) {
                        /* If there are no more slots, expire the oldest */
                        found = oldest;
                        clear_bss_descriptor(found);
                        list_move_tail(&found->list, &priv->network_list);
                } else {
                        continue;
                }

                lbs_deb_scan("SCAN_RESP: BSSID %pM\n", new.bssid);

                /* Copy the locally created newbssentry to the scan table */
                memcpy(found, &new, offsetof(struct bss_descriptor, list));
        }

        ret = 0;

done:
        lbs_deb_leave_args(LBS_DEB_SCAN, "ret %d", ret);
        return ret;
}