src/ap/wmm.c

   1 /*
   2  * hostapd / WMM (Wi-Fi Multimedia)
   3  * Copyright 2002-2003, Instant802 Networks, Inc.
   4  * Copyright 2005-2006, Devicescape Software, Inc.
   5  * Copyright (c) 2009, Jouni Malinen <j@w1.fi>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * Alternatively, this software may be distributed under the terms of BSD
  12  * license.
  13  *
  14  * See README and COPYING for more details.
  15  */
  16
  17 #include "utils/includes.h"
  18
  19 #include "utils/common.h"
  20 #include "common/ieee802_11_defs.h"
  21 #include "common/ieee802_11_common.h"
  22 #include "hostapd.h"
  23 #include "ieee802_11.h"
  24 #include "sta_info.h"
  25 #include "ap_config.h"
  26 #include "wmm.h"
  27
  28
  29 /* TODO: maintain separate sequence and fragment numbers for each AC
  30  * TODO: IGMP snooping to track which multicasts to forward - and use QOS-DATA
  31  * if only WMM stations are receiving a certain group */
  32
  33
  34 static inline u8 wmm_aci_aifsn(int aifsn, int acm, int aci)
  35 {
  36         u8 ret;
  37         ret = (aifsn << WMM_AC_AIFNS_SHIFT) & WMM_AC_AIFSN_MASK;
  38         if (acm)
  39                 ret |= WMM_AC_ACM;
  40         ret |= (aci << WMM_AC_ACI_SHIFT) & WMM_AC_ACI_MASK;
  41         return ret;
  42 }
  43
  44
  45 static inline u8 wmm_ecw(int ecwmin, int ecwmax)
  46 {
  47         return ((ecwmin << WMM_AC_ECWMIN_SHIFT) & WMM_AC_ECWMIN_MASK) |
  48                 ((ecwmax << WMM_AC_ECWMAX_SHIFT) & WMM_AC_ECWMAX_MASK);
  49 }
  50
  51
  52 /*
  53  * Add WMM Parameter Element to Beacon, Probe Response, and (Re)Association
  54  * Response frames.
  55  */
  56 u8 * hostapd_eid_wmm(struct hostapd_data *hapd, u8 *eid)
  57 {
  58         u8 *pos = eid;
  59         struct wmm_parameter_element *wmm =
  60                 (struct wmm_parameter_element *) (pos + 2);
  61         int e;
  62
  63         if (!hapd->conf->wmm_enabled)
  64                 return eid;
  65         eid[0] = WLAN_EID_VENDOR_SPECIFIC;
  66         wmm->oui[0] = 0x00;
  67         wmm->oui[1] = 0x50;
  68         wmm->oui[2] = 0xf2;
  69         wmm->oui_type = WMM_OUI_TYPE;
  70         wmm->oui_subtype = WMM_OUI_SUBTYPE_PARAMETER_ELEMENT;
  71         wmm->version = WMM_VERSION;
  72         wmm->qos_info = hapd->parameter_set_count & 0xf;
  73
  74         /* fill in a parameter set record for each AC */
  75         for (e = 0; e < 4; e++) {
  76                 struct wmm_ac_parameter *ac = &wmm->ac[e];
  77                 struct hostapd_wmm_ac_params *acp =
  78                         &hapd->iconf->wmm_ac_params[e];
  79
  80                 ac->aci_aifsn = wmm_aci_aifsn(acp->aifs,
  81                                               acp->admission_control_mandatory,
  82                                               e);
  83                 ac->cw = wmm_ecw(acp->cwmin, acp->cwmax);
  84                 ac->txop_limit = host_to_le16(acp->txop_limit);
  85         }
  86
  87         pos = (u8 *) (wmm + 1);
  88         eid[1] = pos - eid - 2; /* element length */
  89
  90         return pos;
  91 }
  92
  93
  94 /* This function is called when a station sends an association request with
  95  * WMM info element. The function returns zero on success or non-zero on any
  96  * error in WMM element. eid does not include Element ID and Length octets. */
  97 int hostapd_eid_wmm_valid(struct hostapd_data *hapd, const u8 *eid, size_t len)
  98 {
  99         struct wmm_information_element *wmm;
 100
 101         wpa_hexdump(MSG_MSGDUMP, "WMM IE", eid, len);
 102
 103         if (len < sizeof(struct wmm_information_element)) {
 104                 wpa_printf(MSG_DEBUG, "Too short WMM IE (len=%lu)",
 105                            (unsigned long) len);
 106                 return -1;
 107         }
 108
 109         wmm = (struct wmm_information_element *) eid;
 110         wpa_printf(MSG_DEBUG, "Validating WMM IE: OUI %02x:%02x:%02x  "
 111                    "OUI type %d  OUI sub-type %d  version %d  QoS info 0x%x",
 112                    wmm->oui[0], wmm->oui[1], wmm->oui[2], wmm->oui_type,
 113                    wmm->oui_subtype, wmm->version, wmm->qos_info);
 114         if (wmm->oui_subtype != WMM_OUI_SUBTYPE_INFORMATION_ELEMENT ||
 115             wmm->version != WMM_VERSION) {
 116                 wpa_printf(MSG_DEBUG, "Unsupported WMM IE Subtype/Version");
 117                 return -1;
 118         }
 119
 120         return 0;
 121 }
 122
 123
 124 static void wmm_send_action(struct hostapd_data *hapd, const u8 *addr,
 125                             const struct wmm_tspec_element *tspec,
 126                             u8 action_code, u8 dialogue_token, u8 status_code)
 127 {
 128         u8 buf[256];
 129         struct ieee80211_mgmt *m = (struct ieee80211_mgmt *) buf;
 130         struct wmm_tspec_element *t = (struct wmm_tspec_element *)
 131                 m->u.action.u.wmm_action.variable;
 132         int len;
 133
 134         hostapd_logger(hapd, addr, HOSTAPD_MODULE_IEEE80211,
 135                        HOSTAPD_LEVEL_DEBUG,
 136                        "action response - reason %d", status_code);
 137         os_memset(buf, 0, sizeof(buf));
 138         m->frame_control = IEEE80211_FC(WLAN_FC_TYPE_MGMT,
 139                                         WLAN_FC_STYPE_ACTION);
 140         os_memcpy(m->da, addr, ETH_ALEN);
 141         os_memcpy(m->sa, hapd->own_addr, ETH_ALEN);
 142         os_memcpy(m->bssid, hapd->own_addr, ETH_ALEN);
 143         m->u.action.category = WLAN_ACTION_WMM;
 144         m->u.action.u.wmm_action.action_code = action_code;
 145         m->u.action.u.wmm_action.dialog_token = dialogue_token;
 146         m->u.action.u.wmm_action.status_code = status_code;
 147         os_memcpy(t, tspec, sizeof(struct wmm_tspec_element));
 148         len = ((u8 *) (t + 1)) - buf;
 149
 150         if (hapd->drv.send_mgmt_frame(hapd, m, len) < 0)
 151                 perror("wmm_send_action: send");
 152 }
 153
 154
 155 int wmm_process_tspec(struct wmm_tspec_element *tspec)
 156 {
 157         int medium_time, pps, duration;
 158         int up, psb, dir, tid;
 159         u16 val, surplus;
 160
 161         up = (tspec->ts_info[1] >> 3) & 0x07;
 162         psb = (tspec->ts_info[1] >> 2) & 0x01;
 163         dir = (tspec->ts_info[0] >> 5) & 0x03;
 164         tid = (tspec->ts_info[0] >> 1) & 0x0f;
 165         wpa_printf(MSG_DEBUG, "WMM: TS Info: UP=%d PSB=%d Direction=%d TID=%d",
 166                    up, psb, dir, tid);
 167         val = le_to_host16(tspec->nominal_msdu_size);
 168         wpa_printf(MSG_DEBUG, "WMM: Nominal MSDU Size: %d%s",
 169                    val & 0x7fff, val & 0x8000 ? " (fixed)" : "");
 170         wpa_printf(MSG_DEBUG, "WMM: Mean Data Rate: %u bps",
 171                    le_to_host32(tspec->mean_data_rate));
 172         wpa_printf(MSG_DEBUG, "WMM: Minimum PHY Rate: %u bps",
 173                    le_to_host32(tspec->minimum_phy_rate));
 174         val = le_to_host16(tspec->surplus_bandwidth_allowance);
 175         wpa_printf(MSG_DEBUG, "WMM: Surplus Bandwidth Allowance: %u.%04u",
 176                    val >> 13, 10000 * (val & 0x1fff) / 0x2000);
 177
 178         val = le_to_host16(tspec->nominal_msdu_size);
 179         if (val == 0) {
 180                 wpa_printf(MSG_DEBUG, "WMM: Invalid Nominal MSDU Size (0)");
 181                 return WMM_ADDTS_STATUS_INVALID_PARAMETERS;
 182         }
 183         /* pps = Ceiling((Mean Data Rate / 8) / Nominal MSDU Size) */
 184         pps = ((le_to_host32(tspec->mean_data_rate) / 8) + val - 1) / val;
 185         wpa_printf(MSG_DEBUG, "WMM: Packets-per-second estimate for TSPEC: %d",
 186                    pps);
 187
 188         if (le_to_host32(tspec->minimum_phy_rate) < 1000000) {
 189                 wpa_printf(MSG_DEBUG, "WMM: Too small Minimum PHY Rate");
 190                 return WMM_ADDTS_STATUS_INVALID_PARAMETERS;
 191         }
 192
 193         duration = (le_to_host16(tspec->nominal_msdu_size) & 0x7fff) * 8 /
 194                 (le_to_host32(tspec->minimum_phy_rate) / 1000000) +
 195                 50 /* FIX: proper SIFS + ACK duration */;
 196
 197         /* unsigned binary number with an implicit binary point after the
 198          * leftmost 3 bits, i.e., 0x2000 = 1.0 */
 199         surplus = le_to_host16(tspec->surplus_bandwidth_allowance);
 200         if (surplus <= 0x2000) {
 201                 wpa_printf(MSG_DEBUG, "WMM: Surplus Bandwidth Allowance not "
 202                            "greater than unity");
 203                 return WMM_ADDTS_STATUS_INVALID_PARAMETERS;
 204         }
 205
 206         medium_time = surplus * pps * duration / 0x2000;
 207         wpa_printf(MSG_DEBUG, "WMM: Estimated medium time: %u", medium_time);
 208
 209         /*
 210          * TODO: store list of granted (and still active) TSPECs and check
 211          * whether there is available medium time for this request. For now,
 212          * just refuse requests that would by themselves take very large
 213          * portion of the available bandwidth.
 214          */
 215         if (medium_time > 750000) {
 216                 wpa_printf(MSG_DEBUG, "WMM: Refuse TSPEC request for over "
 217                            "75%% of available bandwidth");
 218                 return WMM_ADDTS_STATUS_REFUSED;
 219         }
 220
 221         /* Convert to 32 microseconds per second unit */
 222         tspec->medium_time = host_to_le16(medium_time / 32);
 223
 224         return WMM_ADDTS_STATUS_ADMISSION_ACCEPTED;
 225 }
 226
 227
 228 static void wmm_addts_req(struct hostapd_data *hapd,
 229                           const struct ieee80211_mgmt *mgmt,
 230                           struct wmm_tspec_element *tspec, size_t len)
 231 {
 232         const u8 *end = ((const u8 *) mgmt) + len;
 233         int res;
 234
 235         if ((const u8 *) (tspec + 1) > end) {
 236                 wpa_printf(MSG_DEBUG, "WMM: TSPEC overflow in ADDTS Request");
 237                 return;
 238         }
 239
 240         wpa_printf(MSG_DEBUG, "WMM: ADDTS Request (Dialog Token %d) for TSPEC "
 241                    "from " MACSTR,
 242                    mgmt->u.action.u.wmm_action.dialog_token,
 243                    MAC2STR(mgmt->sa));
 244
 245         res = wmm_process_tspec(tspec);
 246         wpa_printf(MSG_DEBUG, "WMM: ADDTS processing result: %d", res);
 247
 248         wmm_send_action(hapd, mgmt->sa, tspec, WMM_ACTION_CODE_ADDTS_RESP,
 249                         mgmt->u.action.u.wmm_action.dialog_token, res);
 250 }
 251
 252
 253 void hostapd_wmm_action(struct hostapd_data *hapd,
 254                         const struct ieee80211_mgmt *mgmt, size_t len)
 255 {
 256         int action_code;
 257         int left = len - IEEE80211_HDRLEN - 4;
 258         const u8 *pos = ((const u8 *) mgmt) + IEEE80211_HDRLEN + 4;
 259         struct ieee802_11_elems elems;
 260         struct sta_info *sta = ap_get_sta(hapd, mgmt->sa);
 261
 262         /* check that the request comes from a valid station */
 263         if (!sta ||
 264             (sta->flags & (WLAN_STA_ASSOC | WLAN_STA_WMM)) !=
 265             (WLAN_STA_ASSOC | WLAN_STA_WMM)) {
 266                 hostapd_logger(hapd, mgmt->sa, HOSTAPD_MODULE_IEEE80211,
 267                                HOSTAPD_LEVEL_DEBUG,
 268                                "wmm action received is not from associated wmm"
 269                                " station");
 270                 /* TODO: respond with action frame refused status code */
 271                 return;
 272         }
 273
 274         /* extract the tspec info element */
 275         if (ieee802_11_parse_elems(pos, left, &elems, 1) == ParseFailed) {
 276                 hostapd_logger(hapd, mgmt->sa, HOSTAPD_MODULE_IEEE80211,
 277                                HOSTAPD_LEVEL_DEBUG,
 278                                "hostapd_wmm_action - could not parse wmm "
 279                                "action");
 280                 /* TODO: respond with action frame invalid parameters status
 281                  * code */
 282                 return;
 283         }
 284
 285         if (!elems.wmm_tspec ||
 286             elems.wmm_tspec_len != (sizeof(struct wmm_tspec_element) - 2)) {
 287                 hostapd_logger(hapd, mgmt->sa, HOSTAPD_MODULE_IEEE80211,
 288                                HOSTAPD_LEVEL_DEBUG,
 289                                "hostapd_wmm_action - missing or wrong length "
 290                                "tspec");
 291                 /* TODO: respond with action frame invalid parameters status
 292                  * code */
 293                 return;
 294         }
 295
 296         /* TODO: check the request is for an AC with ACM set, if not, refuse
 297          * request */
 298
 299         action_code = mgmt->u.action.u.wmm_action.action_code;
 300         switch (action_code) {
 301         case WMM_ACTION_CODE_ADDTS_REQ:
 302                 wmm_addts_req(hapd, mgmt, (struct wmm_tspec_element *)
 303                               (elems.wmm_tspec - 2), len);
 304                 return;
 305 #if 0
 306         /* TODO: needed for client implementation */
 307         case WMM_ACTION_CODE_ADDTS_RESP:
 308                 wmm_setup_request(hapd, mgmt, len);
 309                 return;
 310         /* TODO: handle station teardown requests */
 311         case WMM_ACTION_CODE_DELTS:
 312                 wmm_teardown(hapd, mgmt, len);
 313                 return;
 314 #endif
 315         }
 316
 317         hostapd_logger(hapd, mgmt->sa, HOSTAPD_MODULE_IEEE80211,
 318                        HOSTAPD_LEVEL_DEBUG,
 319                        "hostapd_wmm_action - unknown action code %d",
 320                        action_code);
 321 }