/*
* 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);
}
static 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);
}