![Jouni Malinen](/assets/img/avatar_default.png)
The new gas_request and gas_response_get commands can be used to request arbitary GAS queries to be performed. These can be used with ANQP or with other (including vendor specific) advertisement protocols. gas_request <BSSID> <AdvProtoID> [Query] gas_response_get <addr> <dialog token> [offset,length] For example, ANQP query for Capability list in interactive wpa_cli session: > gas_request 02:00:00:00:01:00 00 000102000101 <3>GAS-RESPONSE-INFO addr=02:00:00:00:01:00 dialog_token=0 status_code=0 resp_len=32 > gas_response_get 02:00:00:00:01:00 00 01011c00010102010501070108010c01dddd0c00506f9a110200020304050607 > gas_response_get 02:00:00:00:01:00 00 0,10 01011c00010102010501 > gas_response_get 02:00:00:00:01:00 00 10,10 070108010c01dddd0c00 > gas_response_get 02:00:00:00:01:00 00 20,10 506f9a11020002030405 > gas_response_get 02:00:00:00:01:00 00 30,2 0607 It should be noted that the maximum length of the response buffer is currently 4096 bytes which allows about 2000 bytes of the response data to be fetched with a single gas_response_get command. If the response is longer, it can be fetched in pieces as shown in the example above. Signed-hostap: Jouni Malinen <jouni@qca.qualcomm.com>
273 lines
6.1 KiB
C
273 lines
6.1 KiB
C
/*
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* Generic advertisement service (GAS) (IEEE 802.11u)
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* Copyright (c) 2009, Atheros Communications
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* Copyright (c) 2011-2012, Qualcomm Atheros
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*
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* This software may be distributed under the terms of the BSD license.
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* See README for more details.
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*/
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#include "includes.h"
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#include "common.h"
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#include "ieee802_11_defs.h"
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#include "gas.h"
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static struct wpabuf *
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gas_build_req(u8 action, u8 dialog_token, size_t size)
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{
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struct wpabuf *buf;
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buf = wpabuf_alloc(100 + size);
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if (buf == NULL)
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return NULL;
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wpabuf_put_u8(buf, WLAN_ACTION_PUBLIC);
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wpabuf_put_u8(buf, action);
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wpabuf_put_u8(buf, dialog_token);
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return buf;
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}
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struct wpabuf * gas_build_initial_req(u8 dialog_token, size_t size)
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{
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return gas_build_req(WLAN_PA_GAS_INITIAL_REQ, dialog_token,
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size);
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}
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struct wpabuf * gas_build_comeback_req(u8 dialog_token)
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{
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return gas_build_req(WLAN_PA_GAS_COMEBACK_REQ, dialog_token, 0);
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}
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static struct wpabuf *
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gas_build_resp(u8 action, u8 dialog_token, u16 status_code, u8 frag_id,
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u8 more, u16 comeback_delay, size_t size)
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{
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struct wpabuf *buf;
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buf = wpabuf_alloc(100 + size);
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if (buf == NULL)
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return NULL;
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wpabuf_put_u8(buf, WLAN_ACTION_PUBLIC);
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wpabuf_put_u8(buf, action);
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wpabuf_put_u8(buf, dialog_token);
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wpabuf_put_le16(buf, status_code);
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if (action == WLAN_PA_GAS_COMEBACK_RESP)
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wpabuf_put_u8(buf, frag_id | (more ? 0x80 : 0));
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wpabuf_put_le16(buf, comeback_delay);
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return buf;
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}
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struct wpabuf *
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gas_build_initial_resp(u8 dialog_token, u16 status_code, u16 comeback_delay,
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size_t size)
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{
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return gas_build_resp(WLAN_PA_GAS_INITIAL_RESP, dialog_token,
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status_code, 0, 0, comeback_delay, size);
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}
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static struct wpabuf *
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gas_build_comeback_resp(u8 dialog_token, u16 status_code, u8 frag_id, u8 more,
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u16 comeback_delay, size_t size)
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{
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return gas_build_resp(WLAN_PA_GAS_COMEBACK_RESP, dialog_token,
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status_code, frag_id, more, comeback_delay,
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size);
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}
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/**
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* gas_add_adv_proto_anqp - Add an Advertisement Protocol element
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* @buf: Buffer to which the element is added
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* @query_resp_len_limit: Query Response Length Limit in units of 256 octets
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* @pame_bi: Pre-Association Message Exchange BSSID Independent (0/1)
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*
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*
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* @query_resp_len_limit is 0 for request and 1-0x7f for response. 0x7f means
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* that the maximum limit is determined by the maximum allowable number of
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* fragments in the GAS Query Response Fragment ID.
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*/
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static void gas_add_adv_proto_anqp(struct wpabuf *buf, u8 query_resp_len_limit,
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u8 pame_bi)
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{
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/* Advertisement Protocol IE */
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wpabuf_put_u8(buf, WLAN_EID_ADV_PROTO);
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wpabuf_put_u8(buf, 2); /* Length */
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wpabuf_put_u8(buf, (query_resp_len_limit & 0x7f) |
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(pame_bi ? 0x80 : 0));
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/* Advertisement Protocol */
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wpabuf_put_u8(buf, ACCESS_NETWORK_QUERY_PROTOCOL);
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}
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struct wpabuf * gas_anqp_build_initial_req(u8 dialog_token, size_t size)
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{
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struct wpabuf *buf;
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buf = gas_build_initial_req(dialog_token, 4 + size);
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if (buf == NULL)
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return NULL;
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gas_add_adv_proto_anqp(buf, 0, 0);
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wpabuf_put(buf, 2); /* Query Request Length to be filled */
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return buf;
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}
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struct wpabuf * gas_anqp_build_initial_resp(u8 dialog_token, u16 status_code,
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u16 comeback_delay, size_t size)
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{
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struct wpabuf *buf;
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buf = gas_build_initial_resp(dialog_token, status_code, comeback_delay,
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4 + size);
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if (buf == NULL)
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return NULL;
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gas_add_adv_proto_anqp(buf, 0x7f, 0);
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wpabuf_put(buf, 2); /* Query Response Length to be filled */
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return buf;
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}
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struct wpabuf * gas_anqp_build_initial_resp_buf(u8 dialog_token,
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u16 status_code,
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u16 comeback_delay,
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struct wpabuf *payload)
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{
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struct wpabuf *buf;
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buf = gas_anqp_build_initial_resp(dialog_token, status_code,
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comeback_delay,
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payload ? wpabuf_len(payload) : 0);
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if (buf == NULL)
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return NULL;
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if (payload)
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wpabuf_put_buf(buf, payload);
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gas_anqp_set_len(buf);
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return buf;
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}
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struct wpabuf * gas_anqp_build_comeback_resp(u8 dialog_token, u16 status_code,
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u8 frag_id, u8 more,
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u16 comeback_delay, size_t size)
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{
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struct wpabuf *buf;
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buf = gas_build_comeback_resp(dialog_token, status_code,
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frag_id, more, comeback_delay, 4 + size);
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if (buf == NULL)
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return NULL;
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gas_add_adv_proto_anqp(buf, 0x7f, 0);
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wpabuf_put(buf, 2); /* Query Response Length to be filled */
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return buf;
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}
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struct wpabuf * gas_anqp_build_comeback_resp_buf(u8 dialog_token,
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u16 status_code,
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u8 frag_id, u8 more,
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u16 comeback_delay,
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struct wpabuf *payload)
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{
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struct wpabuf *buf;
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buf = gas_anqp_build_comeback_resp(dialog_token, status_code, frag_id,
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more, comeback_delay,
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payload ? wpabuf_len(payload) : 0);
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if (buf == NULL)
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return NULL;
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if (payload)
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wpabuf_put_buf(buf, payload);
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gas_anqp_set_len(buf);
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return buf;
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}
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/**
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* gas_anqp_set_len - Set Query Request/Response Length
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* @buf: GAS message
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*
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* This function is used to update the Query Request/Response Length field once
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* the payload has been filled.
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*/
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void gas_anqp_set_len(struct wpabuf *buf)
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{
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u8 action;
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size_t offset;
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u8 *len;
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if (buf == NULL || wpabuf_len(buf) < 2)
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return;
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action = *(wpabuf_head_u8(buf) + 1);
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switch (action) {
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case WLAN_PA_GAS_INITIAL_REQ:
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offset = 3 + 4;
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break;
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case WLAN_PA_GAS_INITIAL_RESP:
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offset = 7 + 4;
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break;
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case WLAN_PA_GAS_COMEBACK_RESP:
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offset = 8 + 4;
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break;
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default:
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return;
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}
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if (wpabuf_len(buf) < offset + 2)
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return;
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len = wpabuf_mhead_u8(buf) + offset;
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WPA_PUT_LE16(len, (u8 *) wpabuf_put(buf, 0) - len - 2);
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}
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/**
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* gas_anqp_add_element - Add ANQP element header
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* @buf: GAS message
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* @info_id: ANQP Info ID
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* Returns: Pointer to the Length field for gas_anqp_set_element_len()
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*/
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u8 * gas_anqp_add_element(struct wpabuf *buf, u16 info_id)
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{
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wpabuf_put_le16(buf, info_id);
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return wpabuf_put(buf, 2); /* Length to be filled */
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}
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/**
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* gas_anqp_set_element_len - Update ANQP element Length field
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* @buf: GAS message
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* @len_pos: Length field position from gas_anqp_add_element()
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*
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* This function is called after the ANQP element payload has been added to the
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* buffer.
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*/
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void gas_anqp_set_element_len(struct wpabuf *buf, u8 *len_pos)
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{
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WPA_PUT_LE16(len_pos, (u8 *) wpabuf_put(buf, 0) - len_pos - 2);
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}
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