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fragattacks/src/ap/ieee802_11_vht.c
Jouni Malinen 03a72eacda VHT: Add an interoperability workaround for 80+80 and 160 MHz channels 
Number of deployed 80 MHz capable VHT stations that do not support 80+80
and 160 MHz bandwidths seem to misbehave when trying to connect to an AP
that advertises 80+80 or 160 MHz channel bandwidth in the VHT Operation
element. To avoid such issues with deployed devices, modify the design
based on newly proposed IEEE 802.11 standard changes.

This allows poorly implemented VHT 80 MHz stations to connect with the
AP in 80 MHz mode. 80+80 and 160 MHz capable stations need to support
the new workaround mechanism to allow full bandwidth to be used.
However, there are more or less no impacted station with 80+80/160
capability deployed.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
2016-02-02 00:09:19 +02:00

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/*
* hostapd / IEEE 802.11ac VHT
* Copyright (c) 2002-2009, Jouni Malinen <j@w1.fi>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of BSD license
*
* See README and COPYING for more details.
*/
#include "utils/includes.h"
#include "utils/common.h"
#include "common/ieee802_11_defs.h"
#include "hostapd.h"
#include "ap_config.h"
#include "sta_info.h"
#include "beacon.h"
#include "ieee802_11.h"
#include "dfs.h"
u8 * hostapd_eid_vht_capabilities(struct hostapd_data *hapd, u8 *eid)
{
struct ieee80211_vht_capabilities *cap;
struct hostapd_hw_modes *mode = hapd->iface->current_mode;
u8 *pos = eid;
if (!mode)
return eid;
if (mode->mode == HOSTAPD_MODE_IEEE80211G && hapd->conf->vendor_vht &&
mode->vht_capab == 0 && hapd->iface->hw_features) {
int i;
for (i = 0; i < hapd->iface->num_hw_features; i++) {
if (hapd->iface->hw_features[i].mode ==
HOSTAPD_MODE_IEEE80211A) {
mode = &hapd->iface->hw_features[i];
break;
}
}
}
*pos++ = WLAN_EID_VHT_CAP;
*pos++ = sizeof(*cap);
cap = (struct ieee80211_vht_capabilities *) pos;
os_memset(cap, 0, sizeof(*cap));
cap->vht_capabilities_info = host_to_le32(
hapd->iface->conf->vht_capab);
/* Supported MCS set comes from hw */
os_memcpy(&cap->vht_supported_mcs_set, mode->vht_mcs_set, 8);
pos += sizeof(*cap);
return pos;
}
u8 * hostapd_eid_vht_operation(struct hostapd_data *hapd, u8 *eid)
{
struct ieee80211_vht_operation *oper;
u8 *pos = eid;
*pos++ = WLAN_EID_VHT_OPERATION;
*pos++ = sizeof(*oper);
oper = (struct ieee80211_vht_operation *) pos;
os_memset(oper, 0, sizeof(*oper));
/*
* center freq = 5 GHz + (5 * index)
* So index 42 gives center freq 5.210 GHz
* which is channel 42 in 5G band
*/
oper->vht_op_info_chan_center_freq_seg0_idx =
hapd->iconf->vht_oper_centr_freq_seg0_idx;
oper->vht_op_info_chan_center_freq_seg1_idx =
hapd->iconf->vht_oper_centr_freq_seg1_idx;
oper->vht_op_info_chwidth = hapd->iconf->vht_oper_chwidth;
if (hapd->iconf->vht_oper_chwidth == 2) {
/*
* Convert 160 MHz channel width to new style as interop
* workaround.
*/
oper->vht_op_info_chwidth = 1;
oper->vht_op_info_chan_center_freq_seg1_idx =
oper->vht_op_info_chan_center_freq_seg0_idx;
if (hapd->iconf->channel <
hapd->iconf->vht_oper_centr_freq_seg0_idx)
oper->vht_op_info_chan_center_freq_seg0_idx -= 8;
else
oper->vht_op_info_chan_center_freq_seg0_idx += 8;
} else if (hapd->iconf->vht_oper_chwidth == 3) {
/*
* Convert 80+80 MHz channel width to new style as interop
* workaround.
*/
oper->vht_op_info_chwidth = 1;
}
/* VHT Basic MCS set comes from hw */
/* Hard code 1 stream, MCS0-7 is a min Basic VHT MCS rates */
oper->vht_basic_mcs_set = host_to_le16(0xfffc);
pos += sizeof(*oper);
return pos;
}
static int check_valid_vht_mcs(struct hostapd_hw_modes *mode,
const u8 *sta_vht_capab)
{
const struct ieee80211_vht_capabilities *vht_cap;
struct ieee80211_vht_capabilities ap_vht_cap;
u16 sta_rx_mcs_set, ap_tx_mcs_set;
int i;
if (!mode)
return 1;
/*
* Disable VHT caps for STAs for which there is not even a single
* allowed MCS in any supported number of streams, i.e., STA is
* advertising 3 (not supported) as VHT MCS rates for all supported
* stream cases.
*/
os_memcpy(&ap_vht_cap.vht_supported_mcs_set, mode->vht_mcs_set,
sizeof(ap_vht_cap.vht_supported_mcs_set));
vht_cap = (const struct ieee80211_vht_capabilities *) sta_vht_capab;
/* AP Tx MCS map vs. STA Rx MCS map */
sta_rx_mcs_set = le_to_host16(vht_cap->vht_supported_mcs_set.rx_map);
ap_tx_mcs_set = le_to_host16(ap_vht_cap.vht_supported_mcs_set.tx_map);
for (i = 0; i < VHT_RX_NSS_MAX_STREAMS; i++) {
if ((ap_tx_mcs_set & (0x3 << (i * 2))) == 3)
continue;
if ((sta_rx_mcs_set & (0x3 << (i * 2))) == 3)
continue;
return 1;
}
wpa_printf(MSG_DEBUG,
"No matching VHT MCS found between AP TX and STA RX");
return 0;
}
u8 * hostapd_eid_wb_chsw_wrapper(struct hostapd_data *hapd, u8 *eid)
{
u8 bw, chan1, chan2 = 0;
int freq1;
if (!hapd->cs_freq_params.channel ||
!hapd->cs_freq_params.vht_enabled)
return eid;
/* bandwidth: 0: 40, 1: 80, 2: 160, 3: 80+80 */
switch (hapd->cs_freq_params.bandwidth) {
case 40:
bw = 0;
break;
case 80:
/* check if it's 80+80 */
if (!hapd->cs_freq_params.center_freq2)
bw = 1;
else
bw = 3;
break;
case 160:
bw = 2;
break;
default:
/* not valid VHT bandwidth or not in CSA */
return eid;
}
freq1 = hapd->cs_freq_params.center_freq1 ?
hapd->cs_freq_params.center_freq1 :
hapd->cs_freq_params.freq;
if (ieee80211_freq_to_chan(freq1, &chan1) !=
HOSTAPD_MODE_IEEE80211A)
return eid;
if (hapd->cs_freq_params.center_freq2 &&
ieee80211_freq_to_chan(hapd->cs_freq_params.center_freq2,
&chan2) != HOSTAPD_MODE_IEEE80211A)
return eid;
*eid++ = WLAN_EID_VHT_CHANNEL_SWITCH_WRAPPER;
*eid++ = 5; /* Length of Channel Switch Wrapper */
*eid++ = WLAN_EID_VHT_WIDE_BW_CHSWITCH;
*eid++ = 3; /* Length of Wide Bandwidth Channel Switch element */
*eid++ = bw; /* New Channel Width */
*eid++ = chan1; /* New Channel Center Frequency Segment 0 */
*eid++ = chan2; /* New Channel Center Frequency Segment 1 */
return eid;
}
u8 * hostapd_eid_txpower_envelope(struct hostapd_data *hapd, u8 *eid)
{
struct hostapd_iface *iface = hapd->iface;
struct hostapd_config *iconf = iface->conf;
struct hostapd_hw_modes *mode = iface->current_mode;
struct hostapd_channel_data *chan;
int dfs, i;
u8 channel, tx_pwr_count, local_pwr_constraint;
int max_tx_power;
u8 tx_pwr;
if (!mode)
return eid;
if (ieee80211_freq_to_chan(iface->freq, &channel) == NUM_HOSTAPD_MODES)
return eid;
for (i = 0; i < mode->num_channels; i++) {
if (mode->channels[i].freq == iface->freq)
break;
}
if (i == mode->num_channels)
return eid;
switch (iface->conf->vht_oper_chwidth) {
case VHT_CHANWIDTH_USE_HT:
if (iconf->secondary_channel == 0) {
/* Max Transmit Power count = 0 (20 MHz) */
tx_pwr_count = 0;
} else {
/* Max Transmit Power count = 1 (20, 40 MHz) */
tx_pwr_count = 1;
}
break;
case VHT_CHANWIDTH_80MHZ:
/* Max Transmit Power count = 2 (20, 40, and 80 MHz) */
tx_pwr_count = 2;
break;
case VHT_CHANWIDTH_80P80MHZ:
case VHT_CHANWIDTH_160MHZ:
/* Max Transmit Power count = 3 (20, 40, 80, 160/80+80 MHz) */
tx_pwr_count = 3;
break;
default:
return eid;
}
/*
* Below local_pwr_constraint logic is referred from
* hostapd_eid_pwr_constraint.
*
* Check if DFS is required by regulatory.
*/
dfs = hostapd_is_dfs_required(hapd->iface);
if (dfs < 0)
dfs = 0;
/*
* In order to meet regulations when TPC is not implemented using
* a transmit power that is below the legal maximum (including any
* mitigation factor) should help. In this case, indicate 3 dB below
* maximum allowed transmit power.
*/
if (hapd->iconf->local_pwr_constraint == -1)
local_pwr_constraint = (dfs == 0) ? 0 : 3;
else
local_pwr_constraint = hapd->iconf->local_pwr_constraint;
/*
* A STA that is not an AP shall use a transmit power less than or
* equal to the local maximum transmit power level for the channel.
* The local maximum transmit power can be calculated from the formula:
* local max TX pwr = max TX pwr - local pwr constraint
* Where max TX pwr is maximum transmit power level specified for
* channel in Country element and local pwr constraint is specified
* for channel in this Power Constraint element.
*/
chan = &mode->channels[i];
max_tx_power = chan->max_tx_power - local_pwr_constraint;
/*
* Local Maximum Transmit power is encoded as two's complement
* with a 0.5 dB step.
*/
max_tx_power *= 2; /* in 0.5 dB steps */
if (max_tx_power > 127) {
/* 63.5 has special meaning of 63.5 dBm or higher */
max_tx_power = 127;
}
if (max_tx_power < -128)
max_tx_power = -128;
if (max_tx_power < 0)
tx_pwr = 0x80 + max_tx_power + 128;
else
tx_pwr = max_tx_power;
*eid++ = WLAN_EID_VHT_TRANSMIT_POWER_ENVELOPE;
*eid++ = 2 + tx_pwr_count;
/*
* Max Transmit Power count and
* Max Transmit Power units = 0 (EIRP)
*/
*eid++ = tx_pwr_count;
for (i = 0; i <= tx_pwr_count; i++)
*eid++ = tx_pwr;
return eid;
}
u16 copy_sta_vht_capab(struct hostapd_data *hapd, struct sta_info *sta,
const u8 *vht_capab)
{
/* Disable VHT caps for STAs associated to no-VHT BSSes. */
if (!vht_capab ||
hapd->conf->disable_11ac ||
!check_valid_vht_mcs(hapd->iface->current_mode, vht_capab)) {
sta->flags &= ~WLAN_STA_VHT;
os_free(sta->vht_capabilities);
sta->vht_capabilities = NULL;
return WLAN_STATUS_SUCCESS;
}
if (sta->vht_capabilities == NULL) {
sta->vht_capabilities =
os_zalloc(sizeof(struct ieee80211_vht_capabilities));
if (sta->vht_capabilities == NULL)
return WLAN_STATUS_UNSPECIFIED_FAILURE;
}
sta->flags |= WLAN_STA_VHT;
os_memcpy(sta->vht_capabilities, vht_capab,
sizeof(struct ieee80211_vht_capabilities));
return WLAN_STATUS_SUCCESS;
}
u16 copy_sta_vendor_vht(struct hostapd_data *hapd, struct sta_info *sta,
const u8 *ie, size_t len)
{
const u8 *vht_capab;
unsigned int vht_capab_len;
if (!ie || len < 5 + 2 + sizeof(struct ieee80211_vht_capabilities) ||
hapd->conf->disable_11ac)
goto no_capab;
/* The VHT Capabilities element embedded in vendor VHT */
vht_capab = ie + 5;
if (vht_capab[0] != WLAN_EID_VHT_CAP)
goto no_capab;
vht_capab_len = vht_capab[1];
if (vht_capab_len < sizeof(struct ieee80211_vht_capabilities) ||
(int) vht_capab_len > ie + len - vht_capab - 2)
goto no_capab;
vht_capab += 2;
if (sta->vht_capabilities == NULL) {
sta->vht_capabilities =
os_zalloc(sizeof(struct ieee80211_vht_capabilities));
if (sta->vht_capabilities == NULL)
return WLAN_STATUS_UNSPECIFIED_FAILURE;
}
sta->flags |= WLAN_STA_VHT | WLAN_STA_VENDOR_VHT;
os_memcpy(sta->vht_capabilities, vht_capab,
sizeof(struct ieee80211_vht_capabilities));
return WLAN_STATUS_SUCCESS;
no_capab:
sta->flags &= ~WLAN_STA_VENDOR_VHT;
return WLAN_STATUS_SUCCESS;
}
u8 * hostapd_eid_vendor_vht(struct hostapd_data *hapd, u8 *eid)
{
u8 *pos = eid;
if (!hapd->iface->current_mode)
return eid;
*pos++ = WLAN_EID_VENDOR_SPECIFIC;
*pos++ = (5 + /* The Vendor OUI, type and subtype */
2 + sizeof(struct ieee80211_vht_capabilities) +
2 + sizeof(struct ieee80211_vht_operation));
WPA_PUT_BE32(pos, (OUI_BROADCOM << 8) | VENDOR_VHT_TYPE);
pos += 4;
*pos++ = VENDOR_VHT_SUBTYPE;
pos = hostapd_eid_vht_capabilities(hapd, pos);
pos = hostapd_eid_vht_operation(hapd, pos);
return pos;
}
u16 set_sta_vht_opmode(struct hostapd_data *hapd, struct sta_info *sta,
const u8 *vht_oper_notif)
{
if (!vht_oper_notif) {
sta->flags &= ~WLAN_STA_VHT_OPMODE_ENABLED;
return WLAN_STATUS_SUCCESS;
}
sta->flags |= WLAN_STA_VHT_OPMODE_ENABLED;
sta->vht_opmode = *vht_oper_notif;
return WLAN_STATUS_SUCCESS;
}
void hostapd_get_vht_capab(struct hostapd_data *hapd,
struct ieee80211_vht_capabilities *vht_cap,
struct ieee80211_vht_capabilities *neg_vht_cap)
{
u32 cap, own_cap, sym_caps;
if (vht_cap == NULL)
return;
os_memcpy(neg_vht_cap, vht_cap, sizeof(*neg_vht_cap));
cap = le_to_host32(neg_vht_cap->vht_capabilities_info);
own_cap = hapd->iconf->vht_capab;
/* mask out symmetric VHT capabilities we don't support */
sym_caps = VHT_CAP_SHORT_GI_80 | VHT_CAP_SHORT_GI_160;
cap &= ~sym_caps | (own_cap & sym_caps);
/* mask out beamformer/beamformee caps if not supported */
if (!(own_cap & VHT_CAP_SU_BEAMFORMER_CAPABLE))
cap &= ~(VHT_CAP_SU_BEAMFORMEE_CAPABLE |
VHT_CAP_BEAMFORMEE_STS_MAX);
if (!(own_cap & VHT_CAP_SU_BEAMFORMEE_CAPABLE))
cap &= ~(VHT_CAP_SU_BEAMFORMER_CAPABLE |
VHT_CAP_SOUNDING_DIMENSION_MAX);
if (!(own_cap & VHT_CAP_MU_BEAMFORMER_CAPABLE))
cap &= ~VHT_CAP_MU_BEAMFORMEE_CAPABLE;
if (!(own_cap & VHT_CAP_MU_BEAMFORMEE_CAPABLE))
cap &= ~VHT_CAP_MU_BEAMFORMER_CAPABLE;
/* mask channel widths we don't support */
switch (own_cap & VHT_CAP_SUPP_CHAN_WIDTH_MASK) {
case VHT_CAP_SUPP_CHAN_WIDTH_160_80PLUS80MHZ:
break;
case VHT_CAP_SUPP_CHAN_WIDTH_160MHZ:
if (cap & VHT_CAP_SUPP_CHAN_WIDTH_160_80PLUS80MHZ) {
cap &= ~VHT_CAP_SUPP_CHAN_WIDTH_160_80PLUS80MHZ;
cap |= VHT_CAP_SUPP_CHAN_WIDTH_160MHZ;
}
break;
default:
cap &= ~VHT_CAP_SUPP_CHAN_WIDTH_MASK;
break;
}
if (!(cap & VHT_CAP_SUPP_CHAN_WIDTH_MASK))
cap &= ~VHT_CAP_SHORT_GI_160;
/*
* if we don't support RX STBC, mask out TX STBC in the STA's HT caps
* if we don't support TX STBC, mask out RX STBC in the STA's HT caps
*/
if (!(own_cap & VHT_CAP_RXSTBC_MASK))
cap &= ~VHT_CAP_TXSTBC;
if (!(own_cap & VHT_CAP_TXSTBC))
cap &= ~VHT_CAP_RXSTBC_MASK;
neg_vht_cap->vht_capabilities_info = host_to_le32(cap);
}
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