/*
 * Copyright (C) 2009-2012 B.A.T.M.A.N. contributors:
 *
 * Marek Lindner
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA
 *
 */

#include "main.h"
#include "gateway_common.h"
#include "gateway_client.h"

/* calculates the gateway class from kbit */
static void kbit_to_gw_bandwidth(int down, int up, long *gw_srv_class)
{
        int mdown = 0, tdown, tup, difference;
        uint8_t sbit, part;

        *gw_srv_class = 0;
        difference = 0x0FFFFFFF;

        /* test all downspeeds */
        for (sbit = 0; sbit < 2; sbit++) {
                for (part = 0; part < 16; part++) {
                        tdown = 32 * (sbit + 2) * (1 << part);

                        if (abs(tdown - down) < difference) {
                                *gw_srv_class = (sbit << 7) + (part << 3);
                                difference = abs(tdown - down);
                                mdown = tdown;
                        }
                }
        }

        /* test all upspeeds */
        difference = 0x0FFFFFFF;

        for (part = 0; part < 8; part++) {
                tup = ((part + 1) * (mdown)) / 8;

                if (abs(tup - up) < difference) {
                        *gw_srv_class = (*gw_srv_class & 0xF8) | part;
                        difference = abs(tup - up);
                }
        }
}

/* returns the up and downspeeds in kbit, calculated from the class */
void gw_bandwidth_to_kbit(uint8_t gw_srv_class, int *down, int *up)
{
        int sbit = (gw_srv_class & 0x80) >> 7;
        int dpart = (gw_srv_class & 0x78) >> 3;
        int upart = (gw_srv_class & 0x07);

        if (!gw_srv_class) {
                *down = 0;
                *up = 0;
                return;
        }

        *down = 32 * (sbit + 2) * (1 << dpart);
        *up = ((upart + 1) * (*down)) / 8;
}

static bool parse_gw_bandwidth(struct net_device *net_dev, char *buff,
                               int *up, int *down)
{
        int ret, multi = 1;
        char *slash_ptr, *tmp_ptr;
        long ldown, lup;

        slash_ptr = strchr(buff, '/');
        if (slash_ptr)
                *slash_ptr = 0;

        if (strlen(buff) > 4) {
                tmp_ptr = buff + strlen(buff) - 4;

                if (strnicmp(tmp_ptr, "mbit", 4) == 0)
                        multi = 1024;

                if ((strnicmp(tmp_ptr, "kbit", 4) == 0) ||
                    (multi > 1))
                        *tmp_ptr = '\0';
        }

        ret = kstrtol(buff, 10, &ldown);
        if (ret) {
                bat_err(net_dev,
                        "Download speed of gateway mode invalid: %s\n",
                        buff);
                return false;
        }

        *down = ldown * multi;

        /* we also got some upload info */
        if (slash_ptr) {
                multi = 1;

                if (strlen(slash_ptr + 1) > 4) {
                        tmp_ptr = slash_ptr + 1 - 4 + strlen(slash_ptr + 1);

                        if (strnicmp(tmp_ptr, "mbit", 4) == 0)
                                multi = 1024;

                        if ((strnicmp(tmp_ptr, "kbit", 4) == 0) ||
                            (multi > 1))
                                *tmp_ptr = '\0';
                }

                ret = kstrtol(slash_ptr + 1, 10, &lup);
                if (ret) {
                        bat_err(net_dev,
                                "Upload speed of gateway mode invalid: %s\n",
                                slash_ptr + 1);
                        return false;
                }

                *up = lup * multi;
        }

        return true;
}

ssize_t gw_bandwidth_set(struct net_device *net_dev, char *buff, size_t count)
{
        struct bat_priv *bat_priv = netdev_priv(net_dev);
        long gw_bandwidth_tmp = 0;
        int up = 0, down = 0;
        bool ret;

        ret = parse_gw_bandwidth(net_dev, buff, &up, &down);
        if (!ret)
                goto end;

        if ((!down) || (down < 256))
                down = 2000;

        if (!up)
                up = down / 5;

        kbit_to_gw_bandwidth(down, up, &gw_bandwidth_tmp);

        /**
         * the gw bandwidth we guessed above might not match the given
         * speeds, hence we need to calculate it back to show the number
         * that is going to be propagated
         **/
        gw_bandwidth_to_kbit((uint8_t)gw_bandwidth_tmp, &down, &up);

        gw_deselect(bat_priv);
        bat_info(net_dev,
                 "Changing gateway bandwidth from: '%i' to: '%ld' (propagating: %d%s/%d%s)\n",
                 atomic_read(&bat_priv->gw_bandwidth), gw_bandwidth_tmp,
                 (down > 2048 ? down / 1024 : down),
                 (down > 2048 ? "MBit" : "KBit"),
                 (up > 2048 ? up / 1024 : up),
                 (up > 2048 ? "MBit" : "KBit"));

        atomic_set(&bat_priv->gw_bandwidth, gw_bandwidth_tmp);

end:
        return count;
}