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