ieee802_11_ht.c

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/*
 * hostapd / IEEE 802.11n HT
 * Copyright (c) 2002-2009, Jouni Malinen <j@w1.fi>
 * Copyright (c) 2007-2008, Intel Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed 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 "drivers/driver.h"
#include "hostapd.h"
#include "ap_config.h"
#include "sta_info.h"
#include "beacon.h"
#include "ieee802_11.h"


u8 * hostapd_eid_ht_capabilities(struct hostapd_data *hapd, u8 *eid)
{
        struct ieee80211_ht_capabilities *cap;
        u8 *pos = eid;

        if (!hapd->iconf->ieee80211n)
                return eid;

        *pos++ = WLAN_EID_HT_CAP;
        *pos++ = sizeof(*cap);

        cap = (struct ieee80211_ht_capabilities *) pos;
        os_memset(cap, 0, sizeof(*cap));
        cap->ht_capabilities_info = host_to_le16(hapd->iconf->ht_capab);
        cap->a_mpdu_params = hapd->iface->current_mode->a_mpdu_params;
        os_memcpy(cap->supported_mcs_set, hapd->iface->current_mode->mcs_set,
                  16);

        /* TODO: ht_extended_capabilities (now fully disabled) */
        /* TODO: tx_bf_capability_info (now fully disabled) */
        /* TODO: asel_capabilities (now fully disabled) */

        pos += sizeof(*cap);

        return pos;
}


u8 * hostapd_eid_ht_operation(struct hostapd_data *hapd, u8 *eid)
{
        struct ieee80211_ht_operation *oper;
        u8 *pos = eid;

        if (!hapd->iconf->ieee80211n)
                return eid;

        *pos++ = WLAN_EID_HT_OPERATION;
        *pos++ = sizeof(*oper);

        oper = (struct ieee80211_ht_operation *) pos;
        os_memset(oper, 0, sizeof(*oper));

        oper->control_chan = hapd->iconf->channel;
        oper->operation_mode = host_to_le16(hapd->iface->ht_op_mode);
        if (hapd->iconf->secondary_channel == 1)
                oper->ht_param |= HT_INFO_HT_PARAM_SECONDARY_CHNL_ABOVE |
                        HT_INFO_HT_PARAM_REC_TRANS_CHNL_WIDTH;
        if (hapd->iconf->secondary_channel == -1)
                oper->ht_param |= HT_INFO_HT_PARAM_SECONDARY_CHNL_BELOW |
                        HT_INFO_HT_PARAM_REC_TRANS_CHNL_WIDTH;

        pos += sizeof(*oper);

        return pos;
}


/*
op_mode
Set to 0 (HT pure) under the followign conditions
        - all STAs in the BSS are 20/40 MHz HT in 20/40 MHz BSS or
        - all STAs in the BSS are 20 MHz HT in 20 MHz BSS
Set to 1 (HT non-member protection) if there may be non-HT STAs
        in both the primary and the secondary channel
Set to 2 if only HT STAs are associated in BSS,
        however and at least one 20 MHz HT STA is associated
Set to 3 (HT mixed mode) when one or more non-HT STAs are associated
        (currently non-GF HT station is considered as non-HT STA also)
*/
int hostapd_ht_operation_update(struct hostapd_iface *iface)
{
        u16 cur_op_mode, new_op_mode;
        int op_mode_changes = 0;

        if (!iface->conf->ieee80211n || iface->conf->ht_op_mode_fixed)
                return 0;

        wpa_printf(MSG_DEBUG, "%s current operation mode=0x%X",
                   __func__, iface->ht_op_mode);

        if (!(iface->ht_op_mode & HT_INFO_OPERATION_MODE_NON_GF_DEVS_PRESENT)
            && iface->num_sta_ht_no_gf) {
                iface->ht_op_mode |=
                        HT_INFO_OPERATION_MODE_NON_GF_DEVS_PRESENT;
                op_mode_changes++;
        } else if ((iface->ht_op_mode &
                    HT_INFO_OPERATION_MODE_NON_GF_DEVS_PRESENT) &&
                   iface->num_sta_ht_no_gf == 0) {
                iface->ht_op_mode &=
                        ~HT_INFO_OPERATION_MODE_NON_GF_DEVS_PRESENT;
                op_mode_changes++;
        }

        if (!(iface->ht_op_mode & HT_INFO_OPERATION_MODE_NON_HT_STA_PRESENT) &&
            (iface->num_sta_no_ht || iface->olbc_ht)) {
                iface->ht_op_mode |= HT_INFO_OPERATION_MODE_NON_HT_STA_PRESENT;
                op_mode_changes++;
        } else if ((iface->ht_op_mode &
                    HT_INFO_OPERATION_MODE_NON_HT_STA_PRESENT) &&
                   (iface->num_sta_no_ht == 0 && !iface->olbc_ht)) {
                iface->ht_op_mode &=
                        ~HT_INFO_OPERATION_MODE_NON_HT_STA_PRESENT;
                op_mode_changes++;
        }

        /* Note: currently we switch to the MIXED op mode if HT non-greenfield
         * station is associated. Probably it's a theoretical case, since
         * it looks like all known HT STAs support greenfield.
         */
        new_op_mode = 0;
        if (iface->num_sta_no_ht ||
            (iface->ht_op_mode & HT_INFO_OPERATION_MODE_NON_GF_DEVS_PRESENT))
                new_op_mode = OP_MODE_MIXED;
        else if ((iface->conf->ht_capab & HT_CAP_INFO_SUPP_CHANNEL_WIDTH_SET)
                 && iface->num_sta_ht_20mhz)
                new_op_mode = OP_MODE_20MHZ_HT_STA_ASSOCED;
        else if (iface->olbc_ht)
                new_op_mode = OP_MODE_MAY_BE_LEGACY_STAS;
        else
                new_op_mode = OP_MODE_PURE;

        cur_op_mode = iface->ht_op_mode & HT_INFO_OPERATION_MODE_OP_MODE_MASK;
        if (cur_op_mode != new_op_mode) {
                iface->ht_op_mode &= ~HT_INFO_OPERATION_MODE_OP_MODE_MASK;
                iface->ht_op_mode |= new_op_mode;
                op_mode_changes++;
        }

        wpa_printf(MSG_DEBUG, "%s new operation mode=0x%X changes=%d",
                   __func__, iface->ht_op_mode, op_mode_changes);

        return op_mode_changes;
}


u16 copy_sta_ht_capab(struct sta_info *sta, const u8 *ht_capab,
                      size_t ht_capab_len)
{
        if (!ht_capab ||
            ht_capab_len < sizeof(struct ieee80211_ht_capabilities)) {
                sta->flags &= ~WLAN_STA_HT;
                os_free(sta->ht_capabilities);
                sta->ht_capabilities = NULL;
                return WLAN_STATUS_SUCCESS;
        }

        if (sta->ht_capabilities == NULL) {
                sta->ht_capabilities =
                        os_zalloc(sizeof(struct ieee80211_ht_capabilities));
                if (sta->ht_capabilities == NULL)
                        return WLAN_STATUS_UNSPECIFIED_FAILURE;
        }

        sta->flags |= WLAN_STA_HT;
        os_memcpy(sta->ht_capabilities, ht_capab,
                  sizeof(struct ieee80211_ht_capabilities));

        return WLAN_STATUS_SUCCESS;
}


static void update_sta_ht(struct hostapd_data *hapd, struct sta_info *sta)
{
        u16 ht_capab;

        ht_capab = le_to_host16(sta->ht_capabilities->ht_capabilities_info);
        wpa_printf(MSG_DEBUG, "HT: STA " MACSTR " HT Capabilities Info: "
                   "0x%04x", MAC2STR(sta->addr), ht_capab);
        if ((ht_capab & HT_CAP_INFO_GREEN_FIELD) == 0) {
                if (!sta->no_ht_gf_set) {
                        sta->no_ht_gf_set = 1;
                        hapd->iface->num_sta_ht_no_gf++;
                }
                wpa_printf(MSG_DEBUG, "%s STA " MACSTR " - no greenfield, num "
                           "of non-gf stations %d",
                           __func__, MAC2STR(sta->addr),
                           hapd->iface->num_sta_ht_no_gf);
        }
        if ((ht_capab & HT_CAP_INFO_SUPP_CHANNEL_WIDTH_SET) == 0) {
                if (!sta->ht_20mhz_set) {
                        sta->ht_20mhz_set = 1;
                        hapd->iface->num_sta_ht_20mhz++;
                }
                wpa_printf(MSG_DEBUG, "%s STA " MACSTR " - 20 MHz HT, num of "
                           "20MHz HT STAs %d",
                           __func__, MAC2STR(sta->addr),
                           hapd->iface->num_sta_ht_20mhz);
        }
}


static void update_sta_no_ht(struct hostapd_data *hapd, struct sta_info *sta)
{
        if (!sta->no_ht_set) {
                sta->no_ht_set = 1;
                hapd->iface->num_sta_no_ht++;
        }
        if (hapd->iconf->ieee80211n) {
                wpa_printf(MSG_DEBUG, "%s STA " MACSTR " - no HT, num of "
                           "non-HT stations %d",
                           __func__, MAC2STR(sta->addr),
                           hapd->iface->num_sta_no_ht);
        }
}


void update_ht_state(struct hostapd_data *hapd, struct sta_info *sta)
{
        if ((sta->flags & WLAN_STA_HT) && sta->ht_capabilities)
                update_sta_ht(hapd, sta);
        else
                update_sta_no_ht(hapd, sta);

        if (hostapd_ht_operation_update(hapd->iface) > 0)
                ieee802_11_set_beacons(hapd->iface);
}


void hostapd_get_ht_capab(struct hostapd_data *hapd,
                          struct ieee80211_ht_capabilities *ht_cap,
                          struct ieee80211_ht_capabilities *neg_ht_cap)
{
        u16 cap;

        if (ht_cap == NULL)
                return;
        os_memcpy(neg_ht_cap, ht_cap, sizeof(*neg_ht_cap));
        cap = le_to_host16(neg_ht_cap->ht_capabilities_info);
        cap &= hapd->iconf->ht_capab;
        cap |= (hapd->iconf->ht_capab & HT_CAP_INFO_SMPS_DISABLED);

        /* FIXME: Rx STBC needs to be handled specially */
        cap |= (hapd->iconf->ht_capab & HT_CAP_INFO_RX_STBC_MASK);
        neg_ht_cap->ht_capabilities_info = host_to_le16(cap);
}