/*

 * P2P - generic helper functions

 * Copyright (c) 2009, Atheros Communications

 *

 * This software may be distributed under the terms of the BSD license.

 * See README for more details.

 */

#include "includes.h"

#include "common.h"

#include "common/defs.h"

#include "common/ieee802_11_common.h"

#include "p2p_i.h"

/**

 * p2p_random - Generate random string for SSID and passphrase

 * @buf: Buffer for returning the result

 * @len: Number of octets to write to the buffer

 * Returns: 0 on success, -1 on failure

 *

 * This function generates a random string using the following character set:

 * 'A'-'Z', 'a'-'z', '0'-'9'.

 */

int p2p_random(char *buf, size_t len)

{

  u8 val;

  size_t i;

  u8 letters = 'Z' - 'A' + 1;

  u8 numbers = 10;

  if (os_get_random((unsigned char *) buf, len))

    return -1;

  /* Character set: 'A'-'Z', 'a'-'z', '0'-'9' */

  for (i = 0; i < len; i++) {

    val = buf[i];

    val %= 2 * letters + numbers;

    if (val < letters)

      buf[i] = 'A' + val;

    else if (val < 2 * letters)

      buf[i] = 'a' + (val - letters);

    else

      buf[i] = '0' + (val - 2 * letters);

  }

  return 0;

}

/**

 * p2p_channel_to_freq - Convert channel info to frequency

 * @op_class: Operating class

 * @channel: Channel number

 * Returns: Frequency in MHz or -1 if the specified channel is unknown

 */

int p2p_channel_to_freq(int op_class, int channel)

{

  return ieee80211_chan_to_freq(NULL, op_class, channel);

}

/**

 * p2p_freq_to_channel - Convert frequency into channel info

 * @op_class: Buffer for returning operating class

 * @channel: Buffer for returning channel number

 * Returns: 0 on success, -1 if the specified frequency is unknown

 */

int p2p_freq_to_channel(unsigned int freq, u8 *op_class, u8 *channel)

{

  if (ieee80211_freq_to_channel_ext(freq, 0, 0, op_class, channel) ==

      NUM_HOSTAPD_MODES)

    return -1;

  return 0;

}

static void p2p_reg_class_intersect(const struct p2p_reg_class *a,

            const struct p2p_reg_class *b,

            struct p2p_reg_class *res)

{

  size_t i, j;

  res->reg_class = a->reg_class;

  for (i = 0; i < a->channels; i++) {

    for (j = 0; j < b->channels; j++) {

      if (a->channel[i] != b->channel[j])

        continue;

      res->channel[res->channels] = a->channel[i];

      res->channels++;

      if (res->channels == P2P_MAX_REG_CLASS_CHANNELS)

        return;

    }

  }

}

/**

 * p2p_channels_intersect - Intersection of supported channel lists

 * @a: First set of supported channels

 * @b: Second set of supported channels

 * @res: Data structure for returning the intersection of support channels

 *

 * This function can be used to find a common set of supported channels. Both

 * input channels sets are assumed to use the same country code. If different

 * country codes are used, the regulatory class numbers may not be matched

 * correctly and results are undefined.

 */

void p2p_channels_intersect(const struct p2p_channels *a,

          const struct p2p_channels *b,

          struct p2p_channels *res)

{

  size_t i, j;

  os_memset(res, 0, sizeof(*res));

  for (i = 0; i < a->reg_classes; i++) {

    const struct p2p_reg_class *a_reg = &a->reg_class[i];

    for (j = 0; j < b->reg_classes; j++) {

      const struct p2p_reg_class *b_reg = &b->reg_class[j];

      if (a_reg->reg_class != b_reg->reg_class)

        continue;

      p2p_reg_class_intersect(

        a_reg, b_reg,

        &res->reg_class[res->reg_classes]);

      if (res->reg_class[res->reg_classes].channels) {

        res->reg_classes++;

        if (res->reg_classes == P2P_MAX_REG_CLASSES)

          return;

      }

    }

  }

}

static void p2p_op_class_union(struct p2p_reg_class *cl,

             const struct p2p_reg_class *b_cl)

{

  size_t i, j;

  for (i = 0; i < b_cl->channels; i++) {

    for (j = 0; j < cl->channels; j++) {

      if (b_cl->channel[i] == cl->channel[j])

        break;

    }

    if (j == cl->channels) {

      if (cl->channels == P2P_MAX_REG_CLASS_CHANNELS)

        return;

      cl->channel[cl->channels++] = b_cl->channel[i];

    }

  }

}

/**

 * p2p_channels_union_inplace - Inplace union of channel lists

 * @res: Input data and place for returning union of the channel sets

 * @b: Second set of channels

 */

void p2p_channels_union_inplace(struct p2p_channels *res,

        const struct p2p_channels *b)

{

  size_t i, j;

  for (i = 0; i < res->reg_classes; i++) {

    struct p2p_reg_class *cl = &res->reg_class[i];

    for (j = 0; j < b->reg_classes; j++) {

      const struct p2p_reg_class *b_cl = &b->reg_class[j];

      if (cl->reg_class != b_cl->reg_class)

        continue;

      p2p_op_class_union(cl, b_cl);

    }

  }

  for (j = 0; j < b->reg_classes; j++) {

    const struct p2p_reg_class *b_cl = &b->reg_class[j];

    for (i = 0; i < res->reg_classes; i++) {

      struct p2p_reg_class *cl = &res->reg_class[i];

      if (cl->reg_class == b_cl->reg_class)

        break;

    }

    if (i == res->reg_classes) {

      if (res->reg_classes == P2P_MAX_REG_CLASSES)

        return;

      os_memcpy(&res->reg_class[res->reg_classes++],

          b_cl, sizeof(struct p2p_reg_class));

    }

  }

}

/**

 * p2p_channels_union - Union of channel lists

 * @a: First set of channels

 * @b: Second set of channels

 * @res: Data structure for returning the union of channels

 */

void p2p_channels_union(const struct p2p_channels *a,

      const struct p2p_channels *b,

      struct p2p_channels *res)

{

  os_memcpy(res, a, sizeof(*res));

  p2p_channels_union_inplace(res, b);

}

void p2p_channels_remove_freqs(struct p2p_channels *chan,

             const struct wpa_freq_range_list *list)

{

  size_t o, c;

  if (list == NULL)

    return;

  o = 0;

  while (o < chan->reg_classes) {

    struct p2p_reg_class *op = &chan->reg_class[o];

    c = 0;

    while (c < op->channels) {

      int freq = p2p_channel_to_freq(op->reg_class,

                   op->channel[c]);

      if (freq > 0 && freq_range_list_includes(list, freq)) {

        op->channels--;

        os_memmove(&op->channel[c],

             &op->channel[c + 1],

             op->channels - c);

      } else

        c++;

    }

    if (op->channels == 0) {

      chan->reg_classes--;

      os_memmove(&chan->reg_class[o], &chan->reg_class[o + 1],

           (chan->reg_classes - o) *

           sizeof(struct p2p_reg_class));

    } else

      o++;

  }

}

/**

 * p2p_channels_includes - Check whether a channel is included in the list

 * @channels: List of supported channels

 * @reg_class: Regulatory class of the channel to search

 * @channel: Channel number of the channel to search

 * Returns: 1 if channel was found or 0 if not

 */

int p2p_channels_includes(const struct p2p_channels *channels, u8 reg_class,

        u8 channel)

{

  size_t i, j;

  for (i = 0; i < channels->reg_classes; i++) {

    const struct p2p_reg_class *reg = &channels->reg_class[i];

    if (reg->reg_class != reg_class)

      continue;

    for (j = 0; j < reg->channels; j++) {

      if (reg->channel[j] == channel)

        return 1;

    }

  }

  return 0;

}

int p2p_channels_includes_freq(const struct p2p_channels *channels,

             unsigned int freq)

{

  size_t i, j;

  for (i = 0; i < channels->reg_classes; i++) {

    const struct p2p_reg_class *reg = &channels->reg_class[i];

    for (j = 0; j < reg->channels; j++) {

      if (p2p_channel_to_freq(reg->reg_class,

            reg->channel[j]) == (int) freq)

        return 1;

    }

  }

  return 0;

}

int p2p_supported_freq(struct p2p_data *p2p, unsigned int freq)

{

  u8 op_reg_class, op_channel;

  if (p2p_freq_to_channel(freq, &op_reg_class, &op_channel) < 0)

    return 0;

  return p2p_channels_includes(&p2p->cfg->channels, op_reg_class,

             op_channel);

}

int p2p_supported_freq_go(struct p2p_data *p2p, unsigned int freq)

{

  u8 op_reg_class, op_channel;

  if (p2p_freq_to_channel(freq, &op_reg_class, &op_channel) < 0)

    return 0;

  return p2p_channels_includes(&p2p->cfg->channels, op_reg_class,

             op_channel) &&

    !freq_range_list_includes(&p2p->no_go_freq, freq);

}

int p2p_supported_freq_cli(struct p2p_data *p2p, unsigned int freq)

{

  u8 op_reg_class, op_channel;

  if (p2p_freq_to_channel(freq, &op_reg_class, &op_channel) < 0)

    return 0;

  return p2p_channels_includes(&p2p->cfg->channels, op_reg_class,

             op_channel) ||

    p2p_channels_includes(&p2p->cfg->cli_channels, op_reg_class,

              op_channel);

}

unsigned int p2p_get_pref_freq(struct p2p_data *p2p,

             const struct p2p_channels *channels)

{

  unsigned int i;

  int freq = 0;

  const struct p2p_channels *tmpc = channels ?

    channels : &p2p->cfg->channels;

  if (tmpc == NULL)

    return 0;

  for (i = 0; p2p->cfg->pref_chan && i < p2p->cfg->num_pref_chan; i++) {

    freq = p2p_channel_to_freq(p2p->cfg->pref_chan[i].op_class,

             p2p->cfg->pref_chan[i].chan);

    if (p2p_channels_includes_freq(tmpc, freq))

      return freq;

  }

  return 0;

}

void p2p_channels_dump(struct p2p_data *p2p, const char *title,

           const struct p2p_channels *chan)

{

  char buf[500], *pos, *end;

  size_t i, j;

  int ret;

  pos = buf;

  end = pos + sizeof(buf);

  for (i = 0; i < chan->reg_classes; i++) {

    const struct p2p_reg_class *c;

    c = &chan->reg_class[i];

    ret = os_snprintf(pos, end - pos, " %u:", c->reg_class);

    if (os_snprintf_error(end - pos, ret))

      break;

    pos += ret;

    for (j = 0; j < c->channels; j++) {

      ret = os_snprintf(pos, end - pos, "%s%u",

            j == 0 ? "" : ",",

            c->channel[j]);

      if (os_snprintf_error(end - pos, ret))

        break;

      pos += ret;

    }

  }

  *pos = '\0';

  p2p_dbg(p2p, "%s:%s", title, buf);

}

static u8 p2p_channel_pick_random(const u8 *channels, unsigned int num_channels)

{

  unsigned int r;

  if (os_get_random((u8 *) &r, sizeof(r)) < 0)

    r = 0;

  r %= num_channels;

  return channels[r];

}

int p2p_channel_select(struct p2p_channels *chans, const int *classes,

           u8 *op_class, u8 *op_channel)

{

  unsigned int i, j;

  for (j = 0; classes == NULL || classes[j]; j++) {

    for (i = 0; i < chans->reg_classes; i++) {

      struct p2p_reg_class *c = &chans->reg_class[i];

      if (c->channels == 0)

        continue;

      if (classes == NULL || c->reg_class == classes[j]) {

        /*

         * Pick one of the available channels in the

         * operating class at random.

         */

        *op_class = c->reg_class;

        *op_channel = p2p_channel_pick_random(

          c->channel, c->channels);

        return 0;

      }

    }

    if (classes == NULL)

      break;

  }

  return -1;

}

int p2p_channel_random_social(struct p2p_channels *chans, u8 *op_class,

            u8 *op_channel,

            struct wpa_freq_range_list *avoid_list,

            struct wpa_freq_range_list *disallow_list)

{

  u8 chan[4];

  unsigned int num_channels = 0;

  /* Try to find available social channels from 2.4 GHz.

   * If the avoid_list includes any of the 2.4 GHz social channels, that

   * channel is not allowed by p2p_channels_includes() rules. However, it

   * is assumed to allow minimal traffic for P2P negotiation, so allow it

   * here for social channel selection unless explicitly disallowed in the

   * disallow_list. */

  if (p2p_channels_includes(chans, 81, 1) ||

      (freq_range_list_includes(avoid_list, 2412) &&

       !freq_range_list_includes(disallow_list, 2412)))

    chan[num_channels++] = 1;

  if (p2p_channels_includes(chans, 81, 6) ||

      (freq_range_list_includes(avoid_list, 2437) &&

       !freq_range_list_includes(disallow_list, 2437)))

    chan[num_channels++] = 6;

  if (p2p_channels_includes(chans, 81, 11) ||

      (freq_range_list_includes(avoid_list, 2462) &&

       !freq_range_list_includes(disallow_list, 2462)))

    chan[num_channels++] = 11;

  /* Try to find available social channels from 60 GHz */

  if (p2p_channels_includes(chans, 180, 2))

    chan[num_channels++] = 2;

  if (num_channels == 0)

    return -1;

  *op_channel = p2p_channel_pick_random(chan, num_channels);

  if (*op_channel == 2)

    *op_class = 180;

  else

    *op_class = 81;

  return 0;

}

int p2p_channels_to_freqs(const struct p2p_channels *channels, int *freq_list,

        unsigned int max_len)

{

  unsigned int i, idx;

  if (!channels || max_len == 0)

    return 0;

  for (i = 0, idx = 0; i < channels->reg_classes; i++) {

    const struct p2p_reg_class *c = &channels->reg_class[i];

    unsigned int j;

    if (idx + 1 == max_len)

      break;

    for (j = 0; j < c->channels; j++) {

      int freq;

      unsigned int k;

      if (idx + 1 == max_len)

        break;

      freq = p2p_channel_to_freq(c->reg_class,

               c->channel[j]);

      if (freq < 0)

        continue;

      for (k = 0; k < idx; k++) {

        if (freq_list[k] == freq)

          break;

      }

      if (k < idx)

        continue;

      freq_list[idx++] = freq;

    }

  }

  freq_list[idx] = 0;

  return idx;

}

void p2p_copy_channels(struct p2p_channels *dst,

           const struct p2p_channels *src, bool allow_6ghz)

{

  size_t i, j;

  if (allow_6ghz) {

    os_memcpy(dst, src, sizeof(struct p2p_channels));

    return;

  }

  for (i = 0, j = 0; i < src->reg_classes; i++) {

    if (is_6ghz_op_class(src->reg_class[i].reg_class))

      continue;

    os_memcpy(&dst->reg_class[j], &src->reg_class[i],

        sizeof(struct p2p_reg_class));

    j++;

  }

  dst->reg_classes = j;

}

int p2p_remove_6ghz_channels(struct weighted_pcl *pref_freq_list, int size)

{

  int i;

  for (i = 0; i < size; i++) {

    if (is_6ghz_freq(pref_freq_list[i].freq)) {

      wpa_printf(MSG_DEBUG, "P2P: Remove 6 GHz channel %d",

           pref_freq_list[i].freq);

      size--;

      os_memmove(&pref_freq_list[i], &pref_freq_list[i + 1],

           (size - i) * sizeof(pref_freq_list[0]));

      i--;

    }

  }

  return i;

}

/**

 * p2p_pref_freq_allowed - Based on the flags set, check if the preferred

 * frequency is allowed

 * @freq_list: Weighted preferred channel list

 * @go: Whether the local device is the group owner

 * Returns: Whether the preferred frequency is allowed

 */

bool p2p_pref_freq_allowed(const struct weighted_pcl *freq_list, bool go)

{

  if (freq_list->flag & WEIGHTED_PCL_EXCLUDE)

    return false;

  if (!(freq_list->flag & WEIGHTED_PCL_CLI) && !go)

    return false;

  if (!(freq_list->flag & WEIGHTED_PCL_GO) && go)

    return false;

  return true;

}

static int p2p_check_pref_channel(int channel, u8 op_class,

          const struct weighted_pcl *freq_list,

          unsigned int num_channels, bool go)

{

  unsigned int i;

  /* If the channel is present in the preferred channel list, check if it

   * has appropriate flags for the role.

   */

  for (i = 0; i < num_channels; i++) {

    if (p2p_channel_to_freq(op_class, channel) !=

        (int) freq_list[i].freq)

      continue;

    if (!p2p_pref_freq_allowed(&freq_list[i], go))

      return -1;

    break;

  }

  return 0;

}

void p2p_pref_channel_filter(const struct p2p_channels *p2p_chan,

           const struct weighted_pcl *freq_list,

           unsigned int num_channels,

           struct p2p_channels *res, bool go)

{

  size_t i, j;

  os_memset(res, 0, sizeof(*res));

  for (i = 0; i < p2p_chan->reg_classes; i++) {

    const struct p2p_reg_class *reg = &p2p_chan->reg_class[i];

    struct p2p_reg_class *res_reg = &res->reg_class[i];

    if (num_channels > 0) {

      for (j = 0; j < reg->channels; j++) {

        if (p2p_check_pref_channel(reg->channel[j],

                 reg->reg_class,

                 freq_list,

                 num_channels,

                 go) < 0)

          continue;

        res_reg->channel[res_reg->channels++] =

          reg->channel[j];

      }

    }

    if (res_reg->channels == 0)

      continue;

    res->reg_classes++;

    res_reg->reg_class = reg->reg_class;

  }

}