/* Helpers for managing scan queues
 *
 * See copyright notice in main.c
 */

#include <linux/gfp.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/ieee80211.h>
#include <net/cfg80211.h>

#include "hermes.h"
#include "orinoco.h"
#include "main.h"

#include "scan.h"

#define ZERO_DBM_OFFSET 0x95
#define MAX_SIGNAL_LEVEL 0x8A
#define MIN_SIGNAL_LEVEL 0x2F

#define SIGNAL_TO_DBM(x)                                        \
        (clamp_t(s32, (x), MIN_SIGNAL_LEVEL, MAX_SIGNAL_LEVEL)  \
         - ZERO_DBM_OFFSET)
#define SIGNAL_TO_MBM(x) (SIGNAL_TO_DBM(x) * 100)

static int symbol_build_supp_rates(u8 *buf, const __le16 *rates)
{
        int i;
        u8 rate;

        buf[0] = WLAN_EID_SUPP_RATES;
        for (i = 0; i < 5; i++) {
                rate = le16_to_cpu(rates[i]);
                /* NULL terminated */
                if (rate == 0x0)
                        break;
                buf[i + 2] = rate;
        }
        buf[1] = i;

        return i + 2;
}

static int prism_build_supp_rates(u8 *buf, const u8 *rates)
{
        int i;

        buf[0] = WLAN_EID_SUPP_RATES;
        for (i = 0; i < 8; i++) {
                /* NULL terminated */
                if (rates[i] == 0x0)
                        break;
                buf[i + 2] = rates[i];
        }
        buf[1] = i;

        /* We might still have another 2 rates, which need to go in
         * extended supported rates */
        if (i == 8 && rates[i] > 0) {
                buf[10] = WLAN_EID_EXT_SUPP_RATES;
                for (; i < 10; i++) {
                        /* NULL terminated */
                        if (rates[i] == 0x0)
                                break;
                        buf[i + 2] = rates[i];
                }
                buf[11] = i - 8;
        }

        return (i < 8) ? i + 2 : i + 4;
}

static void orinoco_add_hostscan_result(struct orinoco_private *priv,
                                        const union hermes_scan_info *bss)
{
        struct wiphy *wiphy = priv_to_wiphy(priv);
        struct ieee80211_channel *channel;
        u8 *ie;
        u8 ie_buf[46];
        u64 timestamp;
        s32 signal;
        u16 capability;
        u16 beacon_interval;
        int ie_len;
        int freq;
        int len;

        len = le16_to_cpu(bss->a.essid_len);

        /* Reconstruct SSID and bitrate IEs to pass up */
        ie_buf[0] = WLAN_EID_SSID;
        ie_buf[1] = len;
        memcpy(&ie_buf[2], bss->a.essid, len);

        ie = ie_buf + len + 2;
        ie_len = ie_buf[1] + 2;
        switch (priv->firmware_type) {
        case FIRMWARE_TYPE_SYMBOL:
                ie_len += symbol_build_supp_rates(ie, bss->s.rates);
                break;

        case FIRMWARE_TYPE_INTERSIL:
                ie_len += prism_build_supp_rates(ie, bss->p.rates);
                break;

        case FIRMWARE_TYPE_AGERE:
        default:
                break;
        }

        freq = ieee80211_dsss_chan_to_freq(le16_to_cpu(bss->a.channel));
        channel = ieee80211_get_channel(wiphy, freq);
        if (!channel) {
                printk(KERN_DEBUG "Invalid channel designation %04X(%04X)",
                        bss->a.channel, freq);
                return; /* Then ignore it for now */
        }
        timestamp = 0;
        capability = le16_to_cpu(bss->a.capabilities);
        beacon_interval = le16_to_cpu(bss->a.beacon_interv);
        signal = SIGNAL_TO_MBM(le16_to_cpu(bss->a.level));

        cfg80211_inform_bss(wiphy, channel, bss->a.bssid, timestamp,
                            capability, beacon_interval, ie_buf, ie_len,
                            signal, GFP_KERNEL);
}

void orinoco_add_extscan_result(struct orinoco_private *priv,
                                struct agere_ext_scan_info *bss,
                                size_t len)
{
        struct wiphy *wiphy = priv_to_wiphy(priv);
        struct ieee80211_channel *channel;
        const u8 *ie;
        u64 timestamp;
        s32 signal;
        u16 capability;
        u16 beacon_interval;
        size_t ie_len;
        int chan, freq;

        ie_len = len - sizeof(*bss);
        ie = cfg80211_find_ie(WLAN_EID_DS_PARAMS, bss->data, ie_len);
        chan = ie ? ie[2] : 0;
        freq = ieee80211_dsss_chan_to_freq(chan);
        channel = ieee80211_get_channel(wiphy, freq);

        timestamp = le64_to_cpu(bss->timestamp);
        capability = le16_to_cpu(bss->capabilities);
        beacon_interval = le16_to_cpu(bss->beacon_interval);
        ie = bss->data;
        signal = SIGNAL_TO_MBM(bss->level);

        cfg80211_inform_bss(wiphy, channel, bss->bssid, timestamp,
                            capability, beacon_interval, ie, ie_len,
                            signal, GFP_KERNEL);
}

void orinoco_add_hostscan_results(struct orinoco_private *priv,
                                  unsigned char *buf,
                                  size_t len)
{
        int offset;             /* In the scan data */
        size_t atom_len;
        bool abort = false;

        switch (priv->firmware_type) {
        case FIRMWARE_TYPE_AGERE:
                atom_len = sizeof(struct agere_scan_apinfo);
                offset = 0;
                break;

        case FIRMWARE_TYPE_SYMBOL:
                /* Lack of documentation necessitates this hack.
                 * Different firmwares have 68 or 76 byte long atoms.
                 * We try modulo first.  If the length divides by both,
                 * we check what would be the channel in the second
                 * frame for a 68-byte atom.  76-byte atoms have 0 there.
                 * Valid channel cannot be 0.  */
                if (len % 76)
                        atom_len = 68;
                else if (len % 68)
                        atom_len = 76;
                else if (len >= 1292 && buf[68] == 0)
                        atom_len = 76;
                else
                        atom_len = 68;
                offset = 0;
                break;

        case FIRMWARE_TYPE_INTERSIL:
                offset = 4;
                if (priv->has_hostscan) {
                        atom_len = le16_to_cpup((__le16 *)buf);
                        /* Sanity check for atom_len */
                        if (atom_len < sizeof(struct prism2_scan_apinfo)) {
                                printk(KERN_ERR "%s: Invalid atom_len in scan "
                                       "data: %zu\n", priv->ndev->name,
                                       atom_len);
                                abort = true;
                                goto scan_abort;
                        }
                } else
                        atom_len = offsetof(struct prism2_scan_apinfo, atim);
                break;

        default:
                abort = true;
                goto scan_abort;
        }

        /* Check that we got an whole number of atoms */
        if ((len - offset) % atom_len) {
                printk(KERN_ERR "%s: Unexpected scan data length %zu, "
                       "atom_len %zu, offset %d\n", priv->ndev->name, len,
                       atom_len, offset);
                abort = true;
                goto scan_abort;
        }

        /* Process the entries one by one */
        for (; offset + atom_len <= len; offset += atom_len) {
                union hermes_scan_info *atom;

                atom = (union hermes_scan_info *) (buf + offset);

                orinoco_add_hostscan_result(priv, atom);
        }

 scan_abort:
        if (priv->scan_request) {
                cfg80211_scan_done(priv->scan_request, abort);
                priv->scan_request = NULL;
        }
}

void orinoco_scan_done(struct orinoco_private *priv, bool abort)
{
        if (priv->scan_request) {
                cfg80211_scan_done(priv->scan_request, abort);
                priv->scan_request = NULL;
        }
}