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/*
* 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;
}
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