wpa_supplicant/wifi_display.c - platform/external/wpa_supplicant_8 - Git at Google

 /*
  * wpa_supplicant - Wi-Fi Display
  * Copyright (c) 2011, Atheros Communications, Inc.
  * Copyright (c) 2011-2012, Qualcomm Atheros, Inc.
  *
  * This software may be distributed under the terms of the BSD license.
  * See README for more details.
  */

 #include "includes.h"

 #include "common.h"
 #include "p2p/p2p.h"
 #include "common/ieee802_11_defs.h"
 #include "wpa_supplicant_i.h"
 #include "wifi_display.h"


 #define WIFI_DISPLAY_SUBELEM_HEADER_LEN 3


 int wifi_display_init(struct wpa_global *global)
 {
 	global->wifi_display = 1;
 	return 0;
 }


 void wifi_display_deinit(struct wpa_global *global)
 {
 	int i;
 	for (i = 0; i < MAX_WFD_SUBELEMS; i++) {
 		wpabuf_free(global->wfd_subelem[i]);
 		global->wfd_subelem[i] = NULL;
 	}
 }


 struct wpabuf * wifi_display_get_wfd_ie(struct wpa_global *global)
 {
 	struct wpabuf *ie;
 	size_t len;
 	int i;

 	if (global->p2p == NULL)
 		return NULL;

 	len = 0;
 	for (i = 0; i < MAX_WFD_SUBELEMS; i++) {
 		if (global->wfd_subelem[i])
 			len += wpabuf_len(global->wfd_subelem[i]);
 	}

 	ie = wpabuf_alloc(len);
 	if (ie == NULL)
 		return NULL;

 	for (i = 0; i < MAX_WFD_SUBELEMS; i++) {
 		if (global->wfd_subelem[i])
 			wpabuf_put_buf(ie, global->wfd_subelem[i]);
 	}

 	return ie;
 }


 static int wifi_display_update_wfd_ie(struct wpa_global *global)
 {
 	struct wpabuf *ie, *buf;
 	size_t len, plen;

 	if (global->p2p == NULL)
 		return 0;

 	wpa_printf(MSG_DEBUG, "WFD: Update WFD IE");

 	if (!global->wifi_display) {
 		wpa_printf(MSG_DEBUG, "WFD: Wi-Fi Display disabled - do not "
 			   "include WFD IE");
 		p2p_set_wfd_ie_beacon(global->p2p, NULL);
 		p2p_set_wfd_ie_probe_req(global->p2p, NULL);
 		p2p_set_wfd_ie_probe_resp(global->p2p, NULL);
 		p2p_set_wfd_ie_assoc_req(global->p2p, NULL);
 		p2p_set_wfd_ie_invitation(global->p2p, NULL);
 		p2p_set_wfd_ie_prov_disc_req(global->p2p, NULL);
 		p2p_set_wfd_ie_prov_disc_resp(global->p2p, NULL);
 		p2p_set_wfd_ie_go_neg(global->p2p, NULL);
 		p2p_set_wfd_dev_info(global->p2p, NULL);
 		p2p_set_wfd_assoc_bssid(global->p2p, NULL);
 		p2p_set_wfd_coupled_sink_info(global->p2p, NULL);
 		return 0;
 	}

 	p2p_set_wfd_dev_info(global->p2p,
 			     global->wfd_subelem[WFD_SUBELEM_DEVICE_INFO]);
 	p2p_set_wfd_assoc_bssid(
 		global->p2p,
 		global->wfd_subelem[WFD_SUBELEM_ASSOCIATED_BSSID]);
 	p2p_set_wfd_coupled_sink_info(
 		global->p2p, global->wfd_subelem[WFD_SUBELEM_COUPLED_SINK]);

 	/*
 	 * WFD IE is included in number of management frames. Two different
 	 * sets of subelements are included depending on the frame:
 	 *
 	 * Beacon, (Re)Association Request, GO Negotiation Req/Resp/Conf,
 	 * Provision Discovery Req:
 	 * WFD Device Info
 	 * [Associated BSSID]
 	 * [Coupled Sink Info]
 	 *
 	 * Probe Request:
 	 * WFD Device Info
 	 * [Associated BSSID]
 	 * [Coupled Sink Info]
 	 * [WFD Extended Capability]
 	 *
 	 * Probe Response:
 	 * WFD Device Info
 	 * [Associated BSSID]
 	 * [Coupled Sink Info]
 	 * [WFD Extended Capability]
 	 * [WFD Session Info]
 	 *
 	 * (Re)Association Response, P2P Invitation Req/Resp,
 	 * Provision Discovery Resp:
 	 * WFD Device Info
 	 * [Associated BSSID]
 	 * [Coupled Sink Info]
 	 * [WFD Session Info]
 	 */
 	len = 0;
 	if (global->wfd_subelem[WFD_SUBELEM_DEVICE_INFO])
 		len += wpabuf_len(global->wfd_subelem[
 					  WFD_SUBELEM_DEVICE_INFO]);
 	if (global->wfd_subelem[WFD_SUBELEM_ASSOCIATED_BSSID])
 		len += wpabuf_len(global->wfd_subelem[
 					  WFD_SUBELEM_ASSOCIATED_BSSID]);
 	if (global->wfd_subelem[WFD_SUBELEM_COUPLED_SINK])
 		len += wpabuf_len(global->wfd_subelem[
 					  WFD_SUBELEM_COUPLED_SINK]);
 	if (global->wfd_subelem[WFD_SUBELEM_SESSION_INFO])
 		len += wpabuf_len(global->wfd_subelem[
 					  WFD_SUBELEM_SESSION_INFO]);
 	if (global->wfd_subelem[WFD_SUBELEM_EXT_CAPAB])
 		len += wpabuf_len(global->wfd_subelem[WFD_SUBELEM_EXT_CAPAB]);
 	buf = wpabuf_alloc(len);
 	if (buf == NULL)
 		return -1;

 	if (global->wfd_subelem[WFD_SUBELEM_DEVICE_INFO])
 		wpabuf_put_buf(buf,
 			       global->wfd_subelem[WFD_SUBELEM_DEVICE_INFO]);
 	if (global->wfd_subelem[WFD_SUBELEM_ASSOCIATED_BSSID])
 		wpabuf_put_buf(buf, global->wfd_subelem[
 				       WFD_SUBELEM_ASSOCIATED_BSSID]);
 	if (global->wfd_subelem[WFD_SUBELEM_COUPLED_SINK])
 		wpabuf_put_buf(buf,
 			       global->wfd_subelem[WFD_SUBELEM_COUPLED_SINK]);

 	ie = wifi_display_encaps(buf);
 	wpa_hexdump_buf(MSG_DEBUG, "WFD: WFD IE for Beacon", ie);
 	p2p_set_wfd_ie_beacon(global->p2p, ie);

 	ie = wifi_display_encaps(buf);
 	wpa_hexdump_buf(MSG_DEBUG, "WFD: WFD IE for (Re)Association Request",
 			ie);
 	p2p_set_wfd_ie_assoc_req(global->p2p, ie);

 	ie = wifi_display_encaps(buf);
 	wpa_hexdump_buf(MSG_DEBUG, "WFD: WFD IE for GO Negotiation", ie);
 	p2p_set_wfd_ie_go_neg(global->p2p, ie);

 	ie = wifi_display_encaps(buf);
 	wpa_hexdump_buf(MSG_DEBUG, "WFD: WFD IE for Provision Discovery "
 			"Request", ie);
 	p2p_set_wfd_ie_prov_disc_req(global->p2p, ie);

 	plen = buf->used;
 	if (global->wfd_subelem[WFD_SUBELEM_EXT_CAPAB])
 		wpabuf_put_buf(buf,
 			       global->wfd_subelem[WFD_SUBELEM_EXT_CAPAB]);

 	ie = wifi_display_encaps(buf);
 	wpa_hexdump_buf(MSG_DEBUG, "WFD: WFD IE for Probe Request", ie);
 	p2p_set_wfd_ie_probe_req(global->p2p, ie);

 	if (global->wfd_subelem[WFD_SUBELEM_SESSION_INFO])
 		wpabuf_put_buf(buf,
 			       global->wfd_subelem[WFD_SUBELEM_SESSION_INFO]);
 	ie = wifi_display_encaps(buf);
 	wpa_hexdump_buf(MSG_DEBUG, "WFD: WFD IE for Probe Response", ie);
 	p2p_set_wfd_ie_probe_resp(global->p2p, ie);

 	/* Remove WFD Extended Capability from buffer */
 	buf->used = plen;
 	if (global->wfd_subelem[WFD_SUBELEM_SESSION_INFO])
 		wpabuf_put_buf(buf,
 			       global->wfd_subelem[WFD_SUBELEM_SESSION_INFO]);

 	ie = wifi_display_encaps(buf);
 	wpa_hexdump_buf(MSG_DEBUG, "WFD: WFD IE for P2P Invitation", ie);
 	p2p_set_wfd_ie_invitation(global->p2p, ie);

 	ie = wifi_display_encaps(buf);
 	wpa_hexdump_buf(MSG_DEBUG, "WFD: WFD IE for Provision Discovery "
 			"Response", ie);
 	p2p_set_wfd_ie_prov_disc_resp(global->p2p, ie);

 	wpabuf_free(buf);

 	return 0;
 }


 void wifi_display_enable(struct wpa_global *global, int enabled)
 {
 	wpa_printf(MSG_DEBUG, "WFD: Wi-Fi Display %s",
 		   enabled ? "enabled" : "disabled");
 	global->wifi_display = enabled;
 	wifi_display_update_wfd_ie(global);
 }


 int wifi_display_subelem_set(struct wpa_global *global, char *cmd)
 {
 	char *pos;
 	int subelem;
 	size_t len;
 	struct wpabuf *e;

 	pos = os_strchr(cmd, ' ');
 	if (pos == NULL)
 		return -1;
 	*pos++ = '\0';

 	len = os_strlen(pos);
 	if (len & 1)
 		return -1;
 	len /= 2;

 	if (os_strcmp(cmd, "all") == 0) {
 		int res;

 		e = wpabuf_alloc(len);
 		if (e == NULL)
 			return -1;
 		if (hexstr2bin(pos, wpabuf_put(e, len), len) < 0) {
 			wpabuf_free(e);
 			return -1;
 		}
 		res = wifi_display_subelem_set_from_ies(global, e);
 		wpabuf_free(e);
 		return res;
 	}

 	subelem = atoi(cmd);
 	if (subelem < 0 || subelem >= MAX_WFD_SUBELEMS)
 		return -1;

 	if (len == 0) {
 		/* Clear subelement */
 		e = NULL;
 		wpa_printf(MSG_DEBUG, "WFD: Clear subelement %d", subelem);
 	} else {
 		e = wpabuf_alloc(1 + len);
 		if (e == NULL)
 			return -1;
 		wpabuf_put_u8(e, subelem);
 		if (hexstr2bin(pos, wpabuf_put(e, len), len) < 0) {
 			wpabuf_free(e);
 			return -1;
 		}
 		wpa_printf(MSG_DEBUG, "WFD: Set subelement %d", subelem);
 	}

 	wpabuf_free(global->wfd_subelem[subelem]);
 	global->wfd_subelem[subelem] = e;
 	wifi_display_update_wfd_ie(global);

 	return 0;
 }


 int wifi_display_subelem_set_from_ies(struct wpa_global *global,
 				      struct wpabuf *ie)
 {
 	int subelements[MAX_WFD_SUBELEMS] = {};
 	const u8 *pos, *end;
 	unsigned int len, subelem;
 	struct wpabuf *e;

 	wpa_printf(MSG_DEBUG, "WFD IEs set: %p - %lu",
 		   ie, ie ? (unsigned long) wpabuf_len(ie) : 0);

 	if (ie == NULL || wpabuf_len(ie) < 6)
 		return -1;

 	pos = wpabuf_head(ie);
 	end = pos + wpabuf_len(ie);

 	while (end > pos) {
 		if (pos + 3 > end)
 			break;

 		len = WPA_GET_BE16(pos + 1) + 3;

 		wpa_printf(MSG_DEBUG, "WFD Sub-Element ID %d - len %d",
 			   *pos, len - 3);

 		if (len > (unsigned int) (end - pos))
 			break;

 		subelem = *pos;
 		if (subelem < MAX_WFD_SUBELEMS && subelements[subelem] == 0) {
 			e = wpabuf_alloc_copy(pos, len);
 			if (e == NULL)
 				return -1;

 			wpabuf_free(global->wfd_subelem[subelem]);
 			global->wfd_subelem[subelem] = e;
 			subelements[subelem] = 1;
 		}

 		pos += len;
 	}

 	for (subelem = 0; subelem < MAX_WFD_SUBELEMS; subelem++) {
 		if (subelements[subelem] == 0) {
 			wpabuf_free(global->wfd_subelem[subelem]);
 			global->wfd_subelem[subelem] = NULL;
 		}
 	}

 	return wifi_display_update_wfd_ie(global);
 }


 int wifi_display_subelem_get(struct wpa_global *global, char *cmd,
 			     char *buf, size_t buflen)
 {
 	int subelem;

 	if (os_strcmp(cmd, "all") == 0) {
 		struct wpabuf *ie;
 		int res;

 		ie = wifi_display_get_wfd_ie(global);
 		if (ie == NULL)
 			return 0;
 		res = wpa_snprintf_hex(buf, buflen, wpabuf_head(ie),
 				       wpabuf_len(ie));
 		wpabuf_free(ie);
 		return res;
 	}

 	subelem = atoi(cmd);
 	if (subelem < 0 || subelem >= MAX_WFD_SUBELEMS)
 		return -1;

 	if (global->wfd_subelem[subelem] == NULL)
 		return 0;

 	return wpa_snprintf_hex(buf, buflen,
 				wpabuf_head_u8(global->wfd_subelem[subelem]) +
 				1,
 				wpabuf_len(global->wfd_subelem[subelem]) - 1);
 }


 char * wifi_display_subelem_hex(const struct wpabuf *wfd_subelems, u8 id)
 {
 	char *subelem = NULL;
 	const u8 *buf;
 	size_t buflen;
 	size_t i = 0;
 	u16 elen;

 	if (!wfd_subelems)
 		return NULL;

 	buf = wpabuf_head_u8(wfd_subelems);
 	if (!buf)
 		return NULL;

 	buflen = wpabuf_len(wfd_subelems);

 	while (i + WIFI_DISPLAY_SUBELEM_HEADER_LEN < buflen) {
 		elen = WPA_GET_BE16(buf + i + 1);
 		if (i + WIFI_DISPLAY_SUBELEM_HEADER_LEN + elen > buflen)
 			break; /* truncated subelement */

 		if (buf[i] == id) {
 			/*
 			 * Limit explicitly to an arbitrary length to avoid
 			 * unnecessarily large allocations. In practice, this
 			 * is limited to maximum frame length anyway, so the
 			 * maximum memory allocation here is not really that
 			 * large. Anyway, the Wi-Fi Display subelements that
 			 * are fetched with this function are even shorter.
 			 */
 			if (elen > 1000)
 				break;
 			subelem = os_zalloc(2 * elen + 1);
 			if (!subelem)
 				return NULL;
 			wpa_snprintf_hex(subelem, 2 * elen + 1,
 					 buf + i +
 					 WIFI_DISPLAY_SUBELEM_HEADER_LEN,
 					 elen);
 			break;
 		}

 		i += elen + WIFI_DISPLAY_SUBELEM_HEADER_LEN;
 	}

 	return subelem;
 }
	/*
	* wpa_supplicant - Wi-Fi Display
	* Copyright (c) 2011, Atheros Communications, Inc.
	* Copyright (c) 2011-2012, Qualcomm Atheros, Inc.
	*
	* This software may be distributed under the terms of the BSD license.
	* See README for more details.
	*/

	#include "includes.h"

	#include "common.h"
	#include "p2p/p2p.h"
	#include "common/ieee802_11_defs.h"
	#include "wpa_supplicant_i.h"
	#include "wifi_display.h"


	#define WIFI_DISPLAY_SUBELEM_HEADER_LEN 3


	int wifi_display_init(struct wpa_global *global)
	{
	global->wifi_display = 1;
	return 0;
	}


	void wifi_display_deinit(struct wpa_global *global)
	{
	int i;
	for (i = 0; i < MAX_WFD_SUBELEMS; i++) {
	wpabuf_free(global->wfd_subelem[i]);
	global->wfd_subelem[i] = NULL;
	}
	}


	struct wpabuf * wifi_display_get_wfd_ie(struct wpa_global *global)
	{
	struct wpabuf *ie;
	size_t len;
	int i;

	if (global->p2p == NULL)
	return NULL;

	len = 0;
	for (i = 0; i < MAX_WFD_SUBELEMS; i++) {
	if (global->wfd_subelem[i])
	len += wpabuf_len(global->wfd_subelem[i]);
	}

	ie = wpabuf_alloc(len);
	if (ie == NULL)
	return NULL;

	for (i = 0; i < MAX_WFD_SUBELEMS; i++) {
	if (global->wfd_subelem[i])
	wpabuf_put_buf(ie, global->wfd_subelem[i]);
	}

	return ie;
	}


	static int wifi_display_update_wfd_ie(struct wpa_global *global)
	{
	struct wpabuf ie, buf;
	size_t len, plen;

	if (global->p2p == NULL)
	return 0;

	wpa_printf(MSG_DEBUG, "WFD: Update WFD IE");

	if (!global->wifi_display) {
	wpa_printf(MSG_DEBUG, "WFD: Wi-Fi Display disabled - do not "
	"include WFD IE");
	p2p_set_wfd_ie_beacon(global->p2p, NULL);
	p2p_set_wfd_ie_probe_req(global->p2p, NULL);
	p2p_set_wfd_ie_probe_resp(global->p2p, NULL);
	p2p_set_wfd_ie_assoc_req(global->p2p, NULL);
	p2p_set_wfd_ie_invitation(global->p2p, NULL);
	p2p_set_wfd_ie_prov_disc_req(global->p2p, NULL);
	p2p_set_wfd_ie_prov_disc_resp(global->p2p, NULL);
	p2p_set_wfd_ie_go_neg(global->p2p, NULL);
	p2p_set_wfd_dev_info(global->p2p, NULL);
	p2p_set_wfd_assoc_bssid(global->p2p, NULL);
	p2p_set_wfd_coupled_sink_info(global->p2p, NULL);
	return 0;
	}

	p2p_set_wfd_dev_info(global->p2p,
	global->wfd_subelem[WFD_SUBELEM_DEVICE_INFO]);
	p2p_set_wfd_assoc_bssid(
	global->p2p,
	global->wfd_subelem[WFD_SUBELEM_ASSOCIATED_BSSID]);
	p2p_set_wfd_coupled_sink_info(
	global->p2p, global->wfd_subelem[WFD_SUBELEM_COUPLED_SINK]);

	/*
	* WFD IE is included in number of management frames. Two different
	* sets of subelements are included depending on the frame:
	*
	* Beacon, (Re)Association Request, GO Negotiation Req/Resp/Conf,
	* Provision Discovery Req:
	* WFD Device Info
	* [Associated BSSID]
	* [Coupled Sink Info]
	*
	* Probe Request:
	* WFD Device Info
	* [Associated BSSID]
	* [Coupled Sink Info]
	* [WFD Extended Capability]
	*
	* Probe Response:
	* WFD Device Info
	* [Associated BSSID]
	* [Coupled Sink Info]
	* [WFD Extended Capability]
	* [WFD Session Info]
	*
	* (Re)Association Response, P2P Invitation Req/Resp,
	* Provision Discovery Resp:
	* WFD Device Info
	* [Associated BSSID]
	* [Coupled Sink Info]
	* [WFD Session Info]
	*/
	len = 0;
	if (global->wfd_subelem[WFD_SUBELEM_DEVICE_INFO])
	len += wpabuf_len(global->wfd_subelem[
	WFD_SUBELEM_DEVICE_INFO]);
	if (global->wfd_subelem[WFD_SUBELEM_ASSOCIATED_BSSID])
	len += wpabuf_len(global->wfd_subelem[
	WFD_SUBELEM_ASSOCIATED_BSSID]);
	if (global->wfd_subelem[WFD_SUBELEM_COUPLED_SINK])
	len += wpabuf_len(global->wfd_subelem[
	WFD_SUBELEM_COUPLED_SINK]);
	if (global->wfd_subelem[WFD_SUBELEM_SESSION_INFO])
	len += wpabuf_len(global->wfd_subelem[
	WFD_SUBELEM_SESSION_INFO]);
	if (global->wfd_subelem[WFD_SUBELEM_EXT_CAPAB])
	len += wpabuf_len(global->wfd_subelem[WFD_SUBELEM_EXT_CAPAB]);
	buf = wpabuf_alloc(len);
	if (buf == NULL)
	return -1;

	if (global->wfd_subelem[WFD_SUBELEM_DEVICE_INFO])
	wpabuf_put_buf(buf,
	global->wfd_subelem[WFD_SUBELEM_DEVICE_INFO]);
	if (global->wfd_subelem[WFD_SUBELEM_ASSOCIATED_BSSID])
	wpabuf_put_buf(buf, global->wfd_subelem[
	WFD_SUBELEM_ASSOCIATED_BSSID]);
	if (global->wfd_subelem[WFD_SUBELEM_COUPLED_SINK])
	wpabuf_put_buf(buf,
	global->wfd_subelem[WFD_SUBELEM_COUPLED_SINK]);

	ie = wifi_display_encaps(buf);
	wpa_hexdump_buf(MSG_DEBUG, "WFD: WFD IE for Beacon", ie);
	p2p_set_wfd_ie_beacon(global->p2p, ie);

	ie = wifi_display_encaps(buf);
	wpa_hexdump_buf(MSG_DEBUG, "WFD: WFD IE for (Re)Association Request",
	ie);
	p2p_set_wfd_ie_assoc_req(global->p2p, ie);

	ie = wifi_display_encaps(buf);
	wpa_hexdump_buf(MSG_DEBUG, "WFD: WFD IE for GO Negotiation", ie);
	p2p_set_wfd_ie_go_neg(global->p2p, ie);

	ie = wifi_display_encaps(buf);
	wpa_hexdump_buf(MSG_DEBUG, "WFD: WFD IE for Provision Discovery "
	"Request", ie);
	p2p_set_wfd_ie_prov_disc_req(global->p2p, ie);

	plen = buf->used;
	if (global->wfd_subelem[WFD_SUBELEM_EXT_CAPAB])
	wpabuf_put_buf(buf,
	global->wfd_subelem[WFD_SUBELEM_EXT_CAPAB]);

	ie = wifi_display_encaps(buf);
	wpa_hexdump_buf(MSG_DEBUG, "WFD: WFD IE for Probe Request", ie);
	p2p_set_wfd_ie_probe_req(global->p2p, ie);

	if (global->wfd_subelem[WFD_SUBELEM_SESSION_INFO])
	wpabuf_put_buf(buf,
	global->wfd_subelem[WFD_SUBELEM_SESSION_INFO]);
	ie = wifi_display_encaps(buf);
	wpa_hexdump_buf(MSG_DEBUG, "WFD: WFD IE for Probe Response", ie);
	p2p_set_wfd_ie_probe_resp(global->p2p, ie);

	/* Remove WFD Extended Capability from buffer */
	buf->used = plen;
	if (global->wfd_subelem[WFD_SUBELEM_SESSION_INFO])
	wpabuf_put_buf(buf,
	global->wfd_subelem[WFD_SUBELEM_SESSION_INFO]);

	ie = wifi_display_encaps(buf);
	wpa_hexdump_buf(MSG_DEBUG, "WFD: WFD IE for P2P Invitation", ie);
	p2p_set_wfd_ie_invitation(global->p2p, ie);

	ie = wifi_display_encaps(buf);
	wpa_hexdump_buf(MSG_DEBUG, "WFD: WFD IE for Provision Discovery "
	"Response", ie);
	p2p_set_wfd_ie_prov_disc_resp(global->p2p, ie);

	wpabuf_free(buf);

	return 0;
	}


	void wifi_display_enable(struct wpa_global *global, int enabled)
	{
	wpa_printf(MSG_DEBUG, "WFD: Wi-Fi Display %s",
	enabled ? "enabled" : "disabled");
	global->wifi_display = enabled;
	wifi_display_update_wfd_ie(global);
	}


	int wifi_display_subelem_set(struct wpa_global global, char cmd)
	{
	char *pos;
	int subelem;
	size_t len;
	struct wpabuf *e;

	pos = os_strchr(cmd, ' ');
	if (pos == NULL)
	return -1;
	*pos++ = '\0';

	len = os_strlen(pos);
	if (len & 1)
	return -1;
	len /= 2;

	if (os_strcmp(cmd, "all") == 0) {
	int res;

	e = wpabuf_alloc(len);
	if (e == NULL)
	return -1;
	if (hexstr2bin(pos, wpabuf_put(e, len), len) < 0) {
	wpabuf_free(e);
	return -1;
	}
	res = wifi_display_subelem_set_from_ies(global, e);
	wpabuf_free(e);
	return res;
	}

	subelem = atoi(cmd);
	if (subelem < 0 \|\| subelem >= MAX_WFD_SUBELEMS)
	return -1;

	if (len == 0) {
	/* Clear subelement */
	e = NULL;
	wpa_printf(MSG_DEBUG, "WFD: Clear subelement %d", subelem);
	} else {
	e = wpabuf_alloc(1 + len);
	if (e == NULL)
	return -1;
	wpabuf_put_u8(e, subelem);
	if (hexstr2bin(pos, wpabuf_put(e, len), len) < 0) {
	wpabuf_free(e);
	return -1;
	}
	wpa_printf(MSG_DEBUG, "WFD: Set subelement %d", subelem);
	}

	wpabuf_free(global->wfd_subelem[subelem]);
	global->wfd_subelem[subelem] = e;
	wifi_display_update_wfd_ie(global);

	return 0;
	}


	int wifi_display_subelem_set_from_ies(struct wpa_global *global,
	struct wpabuf *ie)
	{
	int subelements[MAX_WFD_SUBELEMS] = {};
	const u8 pos, end;
	unsigned int len, subelem;
	struct wpabuf *e;

	wpa_printf(MSG_DEBUG, "WFD IEs set: %p - %lu",
	ie, ie ? (unsigned long) wpabuf_len(ie) : 0);

	if (ie == NULL \|\| wpabuf_len(ie) < 6)
	return -1;

	pos = wpabuf_head(ie);
	end = pos + wpabuf_len(ie);

	while (end > pos) {
	if (pos + 3 > end)
	break;

	len = WPA_GET_BE16(pos + 1) + 3;

	wpa_printf(MSG_DEBUG, "WFD Sub-Element ID %d - len %d",
	*pos, len - 3);

	if (len > (unsigned int) (end - pos))
	break;

	subelem = *pos;
	if (subelem < MAX_WFD_SUBELEMS && subelements[subelem] == 0) {
	e = wpabuf_alloc_copy(pos, len);
	if (e == NULL)
	return -1;

	wpabuf_free(global->wfd_subelem[subelem]);
	global->wfd_subelem[subelem] = e;
	subelements[subelem] = 1;
	}

	pos += len;
	}

	for (subelem = 0; subelem < MAX_WFD_SUBELEMS; subelem++) {
	if (subelements[subelem] == 0) {
	wpabuf_free(global->wfd_subelem[subelem]);
	global->wfd_subelem[subelem] = NULL;
	}
	}

	return wifi_display_update_wfd_ie(global);
	}


	int wifi_display_subelem_get(struct wpa_global global, char cmd,
	char *buf, size_t buflen)
	{
	int subelem;

	if (os_strcmp(cmd, "all") == 0) {
	struct wpabuf *ie;
	int res;

	ie = wifi_display_get_wfd_ie(global);
	if (ie == NULL)
	return 0;
	res = wpa_snprintf_hex(buf, buflen, wpabuf_head(ie),
	wpabuf_len(ie));
	wpabuf_free(ie);
	return res;
	}

	subelem = atoi(cmd);
	if (subelem < 0 \|\| subelem >= MAX_WFD_SUBELEMS)
	return -1;

	if (global->wfd_subelem[subelem] == NULL)
	return 0;

	return wpa_snprintf_hex(buf, buflen,
	wpabuf_head_u8(global->wfd_subelem[subelem]) +
	1,
	wpabuf_len(global->wfd_subelem[subelem]) - 1);
	}


	char * wifi_display_subelem_hex(const struct wpabuf *wfd_subelems, u8 id)
	{
	char *subelem = NULL;
	const u8 *buf;
	size_t buflen;
	size_t i = 0;
	u16 elen;

	if (!wfd_subelems)
	return NULL;

	buf = wpabuf_head_u8(wfd_subelems);
	if (!buf)
	return NULL;

	buflen = wpabuf_len(wfd_subelems);

	while (i + WIFI_DISPLAY_SUBELEM_HEADER_LEN < buflen) {
	elen = WPA_GET_BE16(buf + i + 1);
	if (i + WIFI_DISPLAY_SUBELEM_HEADER_LEN + elen > buflen)
	break; /* truncated subelement */

	if (buf[i] == id) {
	/*
	* Limit explicitly to an arbitrary length to avoid
	* unnecessarily large allocations. In practice, this
	* is limited to maximum frame length anyway, so the
	* maximum memory allocation here is not really that
	* large. Anyway, the Wi-Fi Display subelements that
	* are fetched with this function are even shorter.
	*/
	if (elen > 1000)
	break;
	subelem = os_zalloc(2 * elen + 1);
	if (!subelem)
	return NULL;
	wpa_snprintf_hex(subelem, 2 * elen + 1,
	buf + i +
	WIFI_DISPLAY_SUBELEM_HEADER_LEN,
	elen);
	break;
	}

	i += elen + WIFI_DISPLAY_SUBELEM_HEADER_LEN;
	}

	return subelem;
	}