/*
 * iwinfo - Wireless Information Library - Linux Wireless Extension Backend
 *
 *   Copyright (C) 2009-2010 Jo-Philipp Wich <xm@subsignal.org>
 *
 * The iwinfo library is free software: you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version 2
 * as published by the Free Software Foundation.
 *
 * The iwinfo library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with the iwinfo library. If not, see http://www.gnu.org/licenses/.
 *
 * Parts of this code are derived from the Linux wireless tools, iwlib.c,
 * iwlist.c and iwconfig.c in particular.
 */

#include "iwinfo.h"
#include "iwinfo_wext.h"

#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>

#define BUFFER_SIZE 0x4000

int system_arg(const char *fmt, ...)
{
    char cmd[BUFFER_SIZE];
    va_list valist;

    va_start(valist, fmt);
    vsnprintf(cmd, BUFFER_SIZE, fmt, valist);
    va_end(valist);

    return system(cmd);
}

int system_s(char *res, int size, const char *cmd)
{
    FILE *fp = popen(cmd, "r");
    if (fp == NULL)
        return -1;
    fread(res, size, 1, fp);
    return pclose(fp);
}

int system_arg_s(char *res, int size, const char *fmt, ...)
{
    char cmd[BUFFER_SIZE];
    va_list valist;

    va_start(valist, fmt);
    vsnprintf(cmd, BUFFER_SIZE, fmt, valist);
    va_end(valist);

    return system_s(res, size, cmd);
}

// check input is ssid or mac address.
int is_ssid(char *ssid)
{
    if (ssid[2] != ':' || ssid[5] != ':' || ssid[8] != ':' ||
        ssid[11] != ':' || ssid[14] != ':' || strlen(ssid) != 17)
        return 1;

    int i;
    for (i = 0; i < 17; i++) {
        if (ssid[i] == ':')
            continue;
        if (ssid[i] < '0' || ssid[i] > '9')
            return 1;
    }
    return 0;
}

uint8_t hex2int(char x)
{
    if (x >= '0' && x <= '9')
        return x - '0';
    if (x >= 'A' && x <= 'F')
        return x - 'A' + 10;
    if (x >= 'a' && x <= 'f')
        return x - 'a' + 10;
    return 0;
}

void format_mac(uint8_t *out, const char *mac)
{
    out[0] = (hex2int(mac[0]) << 4) + hex2int(mac[1]);
    out[1] = (hex2int(mac[3]) << 4) + hex2int(mac[4]);
    out[2] = (hex2int(mac[6]) << 4) + hex2int(mac[7]);
    out[3] = (hex2int(mac[9]) << 4) + hex2int(mac[10]);
    out[4] = (hex2int(mac[12]) << 4) + hex2int(mac[13]);
    out[5] = (hex2int(mac[15]) << 4) + hex2int(mac[16]);
}

uint8_t format_quality(int8_t rssi)
{
    if (rssi >= -50)
        return 100;
    else if (rssi >= -80)    /* between -50 ~ -80dbm*/
        return (24 + ((rssi + 80) * 26) / 10);
    else if (rssi >= -90)   /* between -80 ~ -90dbm*/
        return (((rssi + 90) * 26) / 10);
    /* < -90 dbm*/
    return 0;
}

int wext_get_scanlist(const char *ifname, char *buf, int *len)
{
    char res[BUFFER_SIZE] = {0};

    system_arg("iwpriv %s set SiteSurvey=1", ifname);
    sleep(1);
    system_arg_s(res, BUFFER_SIZE, "iwpriv %s get_site_survey", ifname);

    *len = 0;       // output buffer length is zero.

    char *line, *curt = strdup(res);
    int count = 0;
    for (line = strsep(&curt, "\n"); line != NULL; line = strsep(&curt, "\n")) {
        if (count++ < 2 || *line == 0)
            continue;

        char *col, *curl = strdup(line), colid = 0;
        struct iwinfo_scanlist_entry *e =
                (struct iwinfo_scanlist_entry *)(buf + *len);
        memset(e, 0, sizeof(struct iwinfo_scanlist_entry));
        for (col = strsep(&curl, " "); col != NULL; col = strsep(&curl, " ")) {
            if (*col == 0)
                continue;

            // channel, ssid, mac, encrypt, signal, proto ...
            switch (colid++) {
            case 0:         // channel
                e->channel = atoi(col);
                break;

            case 1:         // ssid
                if (is_ssid(col)) {
                    snprintf(e->ssid, sizeof(e->ssid), "%s", col);
                } else {    // it is mac address
                    format_mac(e->mac, col);
                    colid++;
                }
                break;

            case 2:           // mac
                format_mac(e->mac, col);
                break;

            case 3:
                e->crypto.enabled = strstr(col, "NONE") ? 0 : 1;

                if (strstr(col, "TKIP"))
                    e->crypto.group_ciphers |= IWINFO_CIPHER_TKIP;
                if (strstr(col, "AES"))
                    e->crypto.group_ciphers |= IWINFO_CIPHER_CCMP;  // FIXME?

                if (strstr(col, "WPA1"))
                    e->crypto.wpa_version |= 1;
                if (strstr(col, "WPA2"))
                    e->crypto.wpa_version |= 2;

                if (strstr(col, "PSK"))
                    e->crypto.auth_suites = IWINFO_KMGMT_PSK;
                // 802.1X and NONE also is a choice of suite, not supported.
                break;

            case 4:
                e->signal = atoi(col);
                e->quality = format_quality(e->signal);
                e->quality_max = 100;
                break;

            case 5:         // deal with other..
                e->mode = IWINFO_OPMODE_MASTER;
                break;

            default:
                break;
            }
        }
        free(curl);

        // move to next.
        *len += sizeof(struct iwinfo_scanlist_entry);
    }
    free(curt);
    return 0;
}