/*

 * Generic advertisement service (GAS) (IEEE 802.11u)

 * Copyright (c) 2009, Atheros Communications

 * Copyright (c) 2011-2012, Qualcomm Atheros

 *

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

 * See README for more details.

 */

#include "includes.h"

#include "common.h"

#include "ieee802_11_defs.h"

#include "gas.h"

static struct wpabuf *

gas_build_req(u8 action, u8 dialog_token, size_t size)

{

  struct wpabuf *buf;

  buf = wpabuf_alloc(100 + size);

  if (buf == NULL)

    return NULL;

  wpabuf_put_u8(buf, WLAN_ACTION_PUBLIC);

  wpabuf_put_u8(buf, action);

  wpabuf_put_u8(buf, dialog_token);

  return buf;

}

struct wpabuf * gas_build_initial_req(u8 dialog_token, size_t size)

{

  return gas_build_req(WLAN_PA_GAS_INITIAL_REQ, dialog_token,

           size);

}

struct wpabuf * gas_build_comeback_req(u8 dialog_token)

{

  return gas_build_req(WLAN_PA_GAS_COMEBACK_REQ, dialog_token, 0);

}

static struct wpabuf *

gas_build_resp(u8 action, u8 dialog_token, u16 status_code, u8 frag_id,

         u8 more, u16 comeback_delay, size_t size)

{

  struct wpabuf *buf;

  buf = wpabuf_alloc(100 + size);

  if (buf == NULL)

    return NULL;

  wpabuf_put_u8(buf, WLAN_ACTION_PUBLIC);

  wpabuf_put_u8(buf, action);

  wpabuf_put_u8(buf, dialog_token);

  wpabuf_put_le16(buf, status_code);

  if (action == WLAN_PA_GAS_COMEBACK_RESP)

    wpabuf_put_u8(buf, frag_id | (more ? 0x80 : 0));

  wpabuf_put_le16(buf, comeback_delay);

  return buf;

}

struct wpabuf *

gas_build_initial_resp(u8 dialog_token, u16 status_code, u16 comeback_delay,

           size_t size)

{

  return gas_build_resp(WLAN_PA_GAS_INITIAL_RESP, dialog_token,

            status_code, 0, 0, comeback_delay, size);

}

struct wpabuf *

gas_build_comeback_resp(u8 dialog_token, u16 status_code, u8 frag_id, u8 more,

      u16 comeback_delay, size_t size)

{

  return gas_build_resp(WLAN_PA_GAS_COMEBACK_RESP, dialog_token,

            status_code, frag_id, more, comeback_delay,

            size);

}

/**

 * gas_add_adv_proto_anqp - Add an Advertisement Protocol element

 * @buf: Buffer to which the element is added

 * @query_resp_len_limit: Query Response Length Limit in units of 256 octets

 * @pame_bi: Pre-Association Message Exchange BSSID Independent (0/1)

 *

 *

 * @query_resp_len_limit is 0 for request and 1-0x7f for response. 0x7f means

 * that the maximum limit is determined by the maximum allowable number of

 * fragments in the GAS Query Response Fragment ID.

 */

static void gas_add_adv_proto_anqp(struct wpabuf *buf, u8 query_resp_len_limit,

           u8 pame_bi)

{

  /* Advertisement Protocol IE */

  wpabuf_put_u8(buf, WLAN_EID_ADV_PROTO);

  wpabuf_put_u8(buf, 2); /* Length */

  wpabuf_put_u8(buf, (query_resp_len_limit & 0x7f) |

          (pame_bi ? 0x80 : 0));

  /* Advertisement Protocol */

  wpabuf_put_u8(buf, ACCESS_NETWORK_QUERY_PROTOCOL);

}

struct wpabuf * gas_anqp_build_initial_req(u8 dialog_token, size_t size)

{

  struct wpabuf *buf;

  buf = gas_build_initial_req(dialog_token, 4 + size);

  if (buf == NULL)

    return NULL;

  gas_add_adv_proto_anqp(buf, 0, 0);

  wpabuf_put(buf, 2); /* Query Request Length to be filled */

  return buf;

}

struct wpabuf * gas_anqp_build_initial_resp(u8 dialog_token, u16 status_code,

              u16 comeback_delay, size_t size)

{

  struct wpabuf *buf;

  buf = gas_build_initial_resp(dialog_token, status_code, comeback_delay,

             4 + size);

  if (buf == NULL)

    return NULL;

  gas_add_adv_proto_anqp(buf, 0x7f, 0);

  wpabuf_put(buf, 2); /* Query Response Length to be filled */

  return buf;

}

struct wpabuf * gas_anqp_build_initial_resp_buf(u8 dialog_token,

            u16 status_code,

            u16 comeback_delay,

            struct wpabuf *payload)

{

  struct wpabuf *buf;

  buf = gas_anqp_build_initial_resp(dialog_token, status_code,

            comeback_delay,

            payload ? wpabuf_len(payload) : 0);

  if (buf == NULL)

    return NULL;

  if (payload)

    wpabuf_put_buf(buf, payload);

  gas_anqp_set_len(buf);

  return buf;

}

struct wpabuf * gas_anqp_build_comeback_resp(u8 dialog_token, u16 status_code,

               u8 frag_id, u8 more,

               u16 comeback_delay, size_t size)

{

  struct wpabuf *buf;

  buf = gas_build_comeback_resp(dialog_token, status_code,

              frag_id, more, comeback_delay, 4 + size);

  if (buf == NULL)

    return NULL;

  gas_add_adv_proto_anqp(buf, 0x7f, 0);

  wpabuf_put(buf, 2); /* Query Response Length to be filled */

  return buf;

}

struct wpabuf * gas_anqp_build_comeback_resp_buf(u8 dialog_token,

             u16 status_code,

             u8 frag_id, u8 more,

             u16 comeback_delay,

             struct wpabuf *payload)

{

  struct wpabuf *buf;

  buf = gas_anqp_build_comeback_resp(dialog_token, status_code, frag_id,

             more, comeback_delay,

             payload ? wpabuf_len(payload) : 0);

  if (buf == NULL)

    return NULL;

  if (payload)

    wpabuf_put_buf(buf, payload);

  gas_anqp_set_len(buf);

  return buf;

}

/**

 * gas_anqp_set_len - Set Query Request/Response Length

 * @buf: GAS message

 *

 * This function is used to update the Query Request/Response Length field once

 * the payload has been filled.

 */

void gas_anqp_set_len(struct wpabuf *buf)

{

  u8 action;

  size_t offset;

  u8 *len;

  if (buf == NULL || wpabuf_len(buf) < 2)

    return;

  action = *(wpabuf_head_u8(buf) + 1);

  switch (action) {

  case WLAN_PA_GAS_INITIAL_REQ:

    offset = 3 + 4;

    break;

  case WLAN_PA_GAS_INITIAL_RESP:

    offset = 7 + 4;

    break;

  case WLAN_PA_GAS_COMEBACK_RESP:

    offset = 8 + 4;

    break;

  default:

    return;

  }

  if (wpabuf_len(buf) < offset + 2)

    return;

  len = wpabuf_mhead_u8(buf) + offset;

  WPA_PUT_LE16(len, (u8 *) wpabuf_put(buf, 0) - len - 2);

}

/**

 * gas_anqp_add_element - Add ANQP element header

 * @buf: GAS message

 * @info_id: ANQP Info ID

 * Returns: Pointer to the Length field for gas_anqp_set_element_len()

 */

u8 * gas_anqp_add_element(struct wpabuf *buf, u16 info_id)

{

  wpabuf_put_le16(buf, info_id);

  return wpabuf_put(buf, 2); /* Length to be filled */

}

/**

 * gas_anqp_set_element_len - Update ANQP element Length field

 * @buf: GAS message

 * @len_pos: Length field position from gas_anqp_add_element()

 *

 * This function is called after the ANQP element payload has been added to the

 * buffer.

 */

void gas_anqp_set_element_len(struct wpabuf *buf, u8 *len_pos)

{

  WPA_PUT_LE16(len_pos, (u8 *) wpabuf_put(buf, 0) - len_pos - 2);

}