[thirdparty/hostap.git] / src / common / ocv.c

/*
 * Operating Channel Validation (OCV)
 * Copyright (c) 2018, Mathy Vanhoef
 *
 * This software may be distributed under the terms of the BSD license.
 * See README for more details.
 */

#include "utils/includes.h"
#include "utils/common.h"
#include "drivers/driver.h"
#include "common/ieee802_11_common.h"
#include "ocv.h"

/**
 * Caller of OCV functionality may use various debug output functions, so store
 * the error here and let the caller use an appropriate debug output function.
 */
char ocv_errorstr[256];


int ocv_derive_all_parameters(struct oci_info *oci)
{
	const struct oper_class_map *op_class_map;

	oci->freq = ieee80211_chan_to_freq(NULL, oci->op_class, oci->channel);
	if (oci->freq < 0) {
		wpa_printf(MSG_INFO,
			   "Error interpreting OCI: unrecognized opclass/channel pair (%d/%d)",
			   oci->op_class, oci->channel);
		return -1;
	}

	op_class_map = get_oper_class(NULL, oci->op_class);
	if (!op_class_map) {
		wpa_printf(MSG_INFO,
			   "Error interpreting OCI: Unrecognized opclass (%d)",
			   oci->op_class);
		return -1;
	}

	oci->chanwidth = oper_class_bw_to_int(op_class_map);
	oci->sec_channel = 0;
	if (op_class_map->bw == BW40PLUS)
		oci->sec_channel = 1;
	else if (op_class_map->bw == BW40MINUS)
		oci->sec_channel = -1;

	return 0;
}


int ocv_insert_oci(struct wpa_channel_info *ci, u8 **argpos)
{
	u8 op_class, channel;
	u8 *pos = *argpos;

	if (ieee80211_chaninfo_to_channel(ci->frequency, ci->chanwidth,
					  ci->sec_channel,
					  &op_class, &channel) < 0) {
		wpa_printf(MSG_WARNING,
			   "Cannot determine operating class and channel for OCI element");
		return -1;
	}

	*pos++ = op_class;
	*pos++ = channel;
	*pos++ = ci->seg1_idx;

	*argpos = pos;
	return 0;
}


int ocv_insert_oci_kde(struct wpa_channel_info *ci, u8 **argpos)
{
	u8 *pos = *argpos;

	*pos++ = WLAN_EID_VENDOR_SPECIFIC;
	*pos++ = RSN_SELECTOR_LEN + 3;
	RSN_SELECTOR_PUT(pos, RSN_KEY_DATA_OCI);
	pos += RSN_SELECTOR_LEN;

	*argpos = pos;
	return ocv_insert_oci(ci, argpos);
}


int ocv_insert_extended_oci(struct wpa_channel_info *ci, u8 *pos)
{
	*pos++ = WLAN_EID_EXTENSION;
	*pos++ = 1 + OCV_OCI_LEN;
	*pos++ = WLAN_EID_EXT_OCV_OCI;
	return ocv_insert_oci(ci, &pos);
}


int ocv_verify_tx_params(const u8 *oci_ie, size_t oci_ie_len,
			 struct wpa_channel_info *ci, int tx_chanwidth,
			 int tx_seg1_idx)
{
	struct oci_info oci;

	if (!oci_ie) {
		os_snprintf(ocv_errorstr, sizeof(ocv_errorstr),
			    "OCV failed: did not receive mandatory OCI");
		return -1;
	}

	if (oci_ie_len != 3) {
		os_snprintf(ocv_errorstr, sizeof(ocv_errorstr),
			    "OCV failed: received OCI of unexpected length (%d)",
			    (int) oci_ie_len);
		return -1;
	}

	os_memset(&oci, 0, sizeof(oci));
	oci.op_class = oci_ie[0];
	oci.channel = oci_ie[1];
	oci.seg1_idx = oci_ie[2];
	if (ocv_derive_all_parameters(&oci) != 0) {
		os_snprintf(ocv_errorstr, sizeof(ocv_errorstr),
			    "OCV failed: unable to interpret received OCI");
		return -1;
	}

	/* Primary frequency used to send frames to STA must match the STA's */
	if ((int) ci->frequency != oci.freq) {
		os_snprintf(ocv_errorstr, sizeof(ocv_errorstr),
			    "OCV failed: primary channel mismatch in received OCI (we use %d but receiver is using %d)",
			    ci->frequency, oci.freq);
		return -1;
	}

	/* We shouldn't transmit with a higher bandwidth than the STA supports
	 */
	if (tx_chanwidth > oci.chanwidth) {
		os_snprintf(ocv_errorstr, sizeof(ocv_errorstr),
			    "OCV failed: channel bandwidth mismatch in received OCI (we use %d but receiver only supports %d)",
			    tx_chanwidth, oci.chanwidth);
		return -1;
	}

	/*
	 * Secondary channel only needs be checked for 40 MHz in the 2.4 GHz
	 * band. In the 5 GHz band it's verified through the primary frequency.
	 * Note that the field ci->sec_channel is only filled in when we use
	 * 40 MHz.
	 */
	if (tx_chanwidth == 40 && ci->frequency < 2500 &&
	    ci->sec_channel != oci.sec_channel) {
		os_snprintf(ocv_errorstr, sizeof(ocv_errorstr),
			    "OCV failed: secondary channel mismatch in received OCI (we use %d but receiver is using %d)",
			    ci->sec_channel, oci.sec_channel);
		return -1;
	}

	/*
	 * When using a 160 or 80+80 MHz channel to transmit, verify that we use
	 * the same segments as the receiver by comparing frequency segment 1.
	 */
	if ((ci->chanwidth == CHAN_WIDTH_160 ||
	     ci->chanwidth == CHAN_WIDTH_80P80) &&
	    tx_seg1_idx != oci.seg1_idx) {
		os_snprintf(ocv_errorstr, sizeof(ocv_errorstr),
			    "OCV failed: frequency segment 1 mismatch in received OCI (we use %d but receiver is using %d)",
			    tx_seg1_idx, oci.seg1_idx);
		return -1;
	}

	return 0;
}
Commit	Line	Data
6ab73efa MV	1	/*
	2	* Operating Channel Validation (OCV)
	3	* Copyright (c) 2018, Mathy Vanhoef
	4	*
	5	* This software may be distributed under the terms of the BSD license.
	6	* See README for more details.
	7	*/
	8
	9	#include "utils/includes.h"
	10	#include "utils/common.h"
	11	#include "drivers/driver.h"
	12	#include "common/ieee802_11_common.h"
	13	#include "ocv.h"
	14
	15	/**
	16	* Caller of OCV functionality may use various debug output functions, so store
	17	* the error here and let the caller use an appropriate debug output function.
	18	*/
	19	char ocv_errorstr[256];
	20
	21
	22	int ocv_derive_all_parameters(struct oci_info *oci)
	23	{
	24	const struct oper_class_map *op_class_map;
	25
	26	oci->freq = ieee80211_chan_to_freq(NULL, oci->op_class, oci->channel);
	27	if (oci->freq < 0) {
	28	wpa_printf(MSG_INFO,
	29	"Error interpreting OCI: unrecognized opclass/channel pair (%d/%d)",
	30	oci->op_class, oci->channel);
	31	return -1;
	32	}
	33
	34	op_class_map = get_oper_class(NULL, oci->op_class);
	35	if (!op_class_map) {
	36	wpa_printf(MSG_INFO,
	37	"Error interpreting OCI: Unrecognized opclass (%d)",
	38	oci->op_class);
	39	return -1;
	40	}
	41
	42	oci->chanwidth = oper_class_bw_to_int(op_class_map);
	43	oci->sec_channel = 0;
	44	if (op_class_map->bw == BW40PLUS)
	45	oci->sec_channel = 1;
	46	else if (op_class_map->bw == BW40MINUS)
	47	oci->sec_channel = -1;
	48
	49	return 0;
	50	}
	51
	52
	53	int ocv_insert_oci(struct wpa_channel_info ci, u8 *argpos)
	54	{
	55	u8 op_class, channel;
	56	u8 pos = argpos;
	57
	58	if (ieee80211_chaninfo_to_channel(ci->frequency, ci->chanwidth,
	59	ci->sec_channel,
	60	&op_class, &channel) < 0) {
	61	wpa_printf(MSG_WARNING,
	62	"Cannot determine operating class and channel for OCI element");
	63	return -1;
	64	}
65
66	*pos++ = op_class;
67	*pos++ = channel;
68	*pos++ = ci->seg1_idx;
69
70	*argpos = pos;
71	return 0;
72	}
73
74
75	int ocv_insert_oci_kde(struct wpa_channel_info ci, u8 *argpos)
76	{
77	u8 pos = argpos;
78
79	*pos++ = WLAN_EID_VENDOR_SPECIFIC;
80	*pos++ = RSN_SELECTOR_LEN + 3;
81	RSN_SELECTOR_PUT(pos, RSN_KEY_DATA_OCI);
82	pos += RSN_SELECTOR_LEN;
83
84	*argpos = pos;
85	return ocv_insert_oci(ci, argpos);
86	}
87
88
89	int ocv_insert_extended_oci(struct wpa_channel_info ci, u8 pos)
90	{
91	*pos++ = WLAN_EID_EXTENSION;
92	*pos++ = 1 + OCV_OCI_LEN;
93	*pos++ = WLAN_EID_EXT_OCV_OCI;
94	return ocv_insert_oci(ci, &pos);
95	}
69765208 MV	96
	97
	98	int ocv_verify_tx_params(const u8 *oci_ie, size_t oci_ie_len,
	99	struct wpa_channel_info *ci, int tx_chanwidth,
	100	int tx_seg1_idx)
	101	{
	102	struct oci_info oci;
	103
	104	if (!oci_ie) {
	105	os_snprintf(ocv_errorstr, sizeof(ocv_errorstr),
	106	"OCV failed: did not receive mandatory OCI");
	107	return -1;
	108	}
	109
	110	if (oci_ie_len != 3) {
	111	os_snprintf(ocv_errorstr, sizeof(ocv_errorstr),
	112	"OCV failed: received OCI of unexpected length (%d)",
	113	(int) oci_ie_len);
	114	return -1;
	115	}
	116
	117	os_memset(&oci, 0, sizeof(oci));
	118	oci.op_class = oci_ie[0];
	119	oci.channel = oci_ie[1];
	120	oci.seg1_idx = oci_ie[2];
	121	if (ocv_derive_all_parameters(&oci) != 0) {
	122	os_snprintf(ocv_errorstr, sizeof(ocv_errorstr),
	123	"OCV failed: unable to interpret received OCI");
	124	return -1;
	125	}
	126
	127	/* Primary frequency used to send frames to STA must match the STA's */
	128	if ((int) ci->frequency != oci.freq) {
	129	os_snprintf(ocv_errorstr, sizeof(ocv_errorstr),
	130	"OCV failed: primary channel mismatch in received OCI (we use %d but receiver is using %d)",
	131	ci->frequency, oci.freq);
	132	return -1;
	133	}
	134
	135	/* We shouldn't transmit with a higher bandwidth than the STA supports
	136	*/
	137	if (tx_chanwidth > oci.chanwidth) {
	138	os_snprintf(ocv_errorstr, sizeof(ocv_errorstr),
	139	"OCV failed: channel bandwidth mismatch in received OCI (we use %d but receiver only supports %d)",
	140	tx_chanwidth, oci.chanwidth);
	141	return -1;
	142	}
	143
	144	/*
	145	* Secondary channel only needs be checked for 40 MHz in the 2.4 GHz
	146	* band. In the 5 GHz band it's verified through the primary frequency.
	147	* Note that the field ci->sec_channel is only filled in when we use
	148	* 40 MHz.
	149	*/
	150	if (tx_chanwidth == 40 && ci->frequency < 2500 &&
	151	ci->sec_channel != oci.sec_channel) {
	152	os_snprintf(ocv_errorstr, sizeof(ocv_errorstr),
	153	"OCV failed: secondary channel mismatch in received OCI (we use %d but receiver is using %d)",
	154	ci->sec_channel, oci.sec_channel);
	155	return -1;
	156	}
	157
	158	/*
	159	* When using a 160 or 80+80 MHz channel to transmit, verify that we use
160	* the same segments as the receiver by comparing frequency segment 1.
161	*/
162	if ((ci->chanwidth == CHAN_WIDTH_160 \|\|
163	ci->chanwidth == CHAN_WIDTH_80P80) &&
164	tx_seg1_idx != oci.seg1_idx) {
165	os_snprintf(ocv_errorstr, sizeof(ocv_errorstr),
166	"OCV failed: frequency segment 1 mismatch in received OCI (we use %d but receiver is using %d)",
167	tx_seg1_idx, oci.seg1_idx);
168	return -1;
169	}
170
171	return 0;
172	}