drivers/uwb/wlp/wlp-lc.c

   1 /*
   2  * WiMedia Logical Link Control Protocol (WLP)
   3  *
   4  * Copyright (C) 2005-2006 Intel Corporation
   5  * Reinette Chatre <reinette.chatre@intel.com>
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License version
   9  * 2 as published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19  * 02110-1301, USA.
  20  *
  21  *
  22  * FIXME: docs
  23  */
  24 #include <linux/wlp.h>
  25 #include <linux/slab.h>
  26
  27 #include "wlp-internal.h"
  28
  29 static
  30 void wlp_neighbor_init(struct wlp_neighbor_e *neighbor)
  31 {
  32         INIT_LIST_HEAD(&neighbor->wssid);
  33 }
  34
  35 /**
  36  * Create area for device information storage
  37  *
  38  * wlp->mutex must be held
  39  */
  40 int __wlp_alloc_device_info(struct wlp *wlp)
  41 {
  42         struct device *dev = &wlp->rc->uwb_dev.dev;
  43         BUG_ON(wlp->dev_info != NULL);
  44         wlp->dev_info = kzalloc(sizeof(struct wlp_device_info), GFP_KERNEL);
  45         if (wlp->dev_info == NULL) {
  46                 dev_err(dev, "WLP: Unable to allocate memory for "
  47                         "device information.\n");
  48                 return -ENOMEM;
  49         }
  50         return 0;
  51 }
  52
  53
  54 /**
  55  * Fill in device information using function provided by driver
  56  *
  57  * wlp->mutex must be held
  58  */
  59 static
  60 void __wlp_fill_device_info(struct wlp *wlp)
  61 {
  62         wlp->fill_device_info(wlp, wlp->dev_info);
  63 }
  64
  65 /**
  66  * Setup device information
  67  *
  68  * Allocate area for device information and populate it.
  69  *
  70  * wlp->mutex must be held
  71  */
  72 int __wlp_setup_device_info(struct wlp *wlp)
  73 {
  74         int result;
  75         struct device *dev = &wlp->rc->uwb_dev.dev;
  76
  77         result = __wlp_alloc_device_info(wlp);
  78         if (result < 0) {
  79                 dev_err(dev, "WLP: Unable to allocate area for "
  80                         "device information.\n");
  81                 return result;
  82         }
  83         __wlp_fill_device_info(wlp);
  84         return 0;
  85 }
  86
  87 /**
  88  * Remove information about neighbor stored temporarily
  89  *
  90  * Information learned during discovey should only be stored when the
  91  * device enrolls in the neighbor's WSS. We do need to store this
  92  * information temporarily in order to present it to the user.
  93  *
  94  * We are only interested in keeping neighbor WSS information if that
  95  * neighbor is accepting enrollment.
  96  *
  97  * should be called with wlp->nbmutex held
  98  */
  99 void wlp_remove_neighbor_tmp_info(struct wlp_neighbor_e *neighbor)
 100 {
 101         struct wlp_wssid_e *wssid_e, *next;
 102         u8 keep;
 103         if (!list_empty(&neighbor->wssid)) {
 104                 list_for_each_entry_safe(wssid_e, next, &neighbor->wssid,
 105                                          node) {
 106                         if (wssid_e->info != NULL) {
 107                                 keep = wssid_e->info->accept_enroll;
 108                                 kfree(wssid_e->info);
 109                                 wssid_e->info = NULL;
 110                                 if (!keep) {
 111                                         list_del(&wssid_e->node);
 112                                         kfree(wssid_e);
 113                                 }
 114                         }
 115                 }
 116         }
 117         if (neighbor->info != NULL) {
 118                 kfree(neighbor->info);
 119                 neighbor->info = NULL;
 120         }
 121 }
 122
 123 /*
 124  * Populate WLP neighborhood cache with neighbor information
 125  *
 126  * A new neighbor is found. If it is discoverable then we add it to the
 127  * neighborhood cache.
 128  *
 129  */
 130 static
 131 int wlp_add_neighbor(struct wlp *wlp, struct uwb_dev *dev)
 132 {
 133         int result = 0;
 134         int discoverable;
 135         struct wlp_neighbor_e *neighbor;
 136
 137         /*
 138          * FIXME:
 139          * Use contents of WLP IE found in beacon cache to determine if
 140          * neighbor is discoverable.
 141          * The device does not support WLP IE yet so this still needs to be
 142          * done. Until then we assume all devices are discoverable.
 143          */
 144         discoverable = 1; /* will be changed when FIXME disappears */
 145         if (discoverable) {
 146                 /* Add neighbor to cache for discovery */
 147                 neighbor = kzalloc(sizeof(*neighbor), GFP_KERNEL);
 148                 if (neighbor == NULL) {
 149                         dev_err(&dev->dev, "Unable to create memory for "
 150                                 "new neighbor. \n");
 151                         result = -ENOMEM;
 152                         goto error_no_mem;
 153                 }
 154                 wlp_neighbor_init(neighbor);
 155                 uwb_dev_get(dev);
 156                 neighbor->uwb_dev = dev;
 157                 list_add(&neighbor->node, &wlp->neighbors);
 158         }
 159 error_no_mem:
 160         return result;
 161 }
 162
 163 /**
 164  * Remove one neighbor from cache
 165  */
 166 static
 167 void __wlp_neighbor_release(struct wlp_neighbor_e *neighbor)
 168 {
 169         struct wlp_wssid_e *wssid_e, *next_wssid_e;
 170
 171         list_for_each_entry_safe(wssid_e, next_wssid_e,
 172                                  &neighbor->wssid, node) {
 173                 list_del(&wssid_e->node);
 174                 kfree(wssid_e);
 175         }
 176         uwb_dev_put(neighbor->uwb_dev);
 177         list_del(&neighbor->node);
 178         kfree(neighbor);
 179 }
 180
 181 /**
 182  * Clear entire neighborhood cache.
 183  */
 184 static
 185 void __wlp_neighbors_release(struct wlp *wlp)
 186 {
 187         struct wlp_neighbor_e *neighbor, *next;
 188         if (list_empty(&wlp->neighbors))
 189                 return;
 190         list_for_each_entry_safe(neighbor, next, &wlp->neighbors, node) {
 191                 __wlp_neighbor_release(neighbor);
 192         }
 193 }
 194
 195 static
 196 void wlp_neighbors_release(struct wlp *wlp)
 197 {
 198         mutex_lock(&wlp->nbmutex);
 199         __wlp_neighbors_release(wlp);
 200         mutex_unlock(&wlp->nbmutex);
 201 }
 202
 203
 204
 205 /**
 206  * Send D1 message to neighbor, receive D2 message
 207  *
 208  * @neighbor: neighbor to which D1 message will be sent
 209  * @wss:      if not NULL, it is an enrollment request for this WSS
 210  * @wssid:    if wss not NULL, this is the wssid of the WSS in which we
 211  *            want to enroll
 212  *
 213  * A D1/D2 exchange is done for one of two reasons: discovery or
 214  * enrollment. If done for discovery the D1 message is sent to the neighbor
 215  * and the contents of the D2 response is stored in a temporary cache.
 216  * If done for enrollment the @wss and @wssid are provided also. In this
 217  * case the D1 message is sent to the neighbor, the D2 response is parsed
 218  * for enrollment of the WSS with wssid.
 219  *
 220  * &wss->mutex is held
 221  */
 222 static
 223 int wlp_d1d2_exchange(struct wlp *wlp, struct wlp_neighbor_e *neighbor,
 224                       struct wlp_wss *wss, struct wlp_uuid *wssid)
 225 {
 226         int result;
 227         struct device *dev = &wlp->rc->uwb_dev.dev;
 228         DECLARE_COMPLETION_ONSTACK(completion);
 229         struct wlp_session session;
 230         struct sk_buff  *skb;
 231         struct wlp_frame_assoc *resp;
 232         struct uwb_dev_addr *dev_addr = &neighbor->uwb_dev->dev_addr;
 233
 234         mutex_lock(&wlp->mutex);
 235         if (!wlp_uuid_is_set(&wlp->uuid)) {
 236                 dev_err(dev, "WLP: UUID is not set. Set via sysfs to "
 237                         "proceed.\n");
 238                 result = -ENXIO;
 239                 goto out;
 240         }
 241         /* Send D1 association frame */
 242         result = wlp_send_assoc_frame(wlp, wss, dev_addr, WLP_ASSOC_D1);
 243         if (result < 0) {
 244                 dev_err(dev, "Unable to send D1 frame to neighbor "
 245                         "%02x:%02x (%d)\n", dev_addr->data[1],
 246                         dev_addr->data[0], result);
 247                 goto out;
 248         }
 249         /* Create session, wait for response */
 250         session.exp_message = WLP_ASSOC_D2;
 251         session.cb = wlp_session_cb;
 252         session.cb_priv = &completion;
 253         session.neighbor_addr = *dev_addr;
 254         BUG_ON(wlp->session != NULL);
 255         wlp->session = &session;
 256         /* Wait for D2/F0 frame */
 257         result = wait_for_completion_interruptible_timeout(&completion,
 258                                                    WLP_PER_MSG_TIMEOUT * HZ);
 259         if (result == 0) {
 260                 result = -ETIMEDOUT;
 261                 dev_err(dev, "Timeout while sending D1 to neighbor "
 262                              "%02x:%02x.\n", dev_addr->data[1],
 263                              dev_addr->data[0]);
 264                 goto error_session;
 265         }
 266         if (result < 0) {
 267                 dev_err(dev, "Unable to discover/enroll neighbor %02x:%02x.\n",
 268                         dev_addr->data[1], dev_addr->data[0]);
 269                 goto error_session;
 270         }
 271         /* Parse message in session->data: it will be either D2 or F0 */
 272         skb = session.data;
 273         resp = (void *) skb->data;
 274
 275         if (resp->type == WLP_ASSOC_F0) {
 276                 result = wlp_parse_f0(wlp, skb);
 277                 if (result < 0)
 278                         dev_err(dev, "WLP: Unable to parse F0 from neighbor "
 279                                 "%02x:%02x.\n", dev_addr->data[1],
 280                                 dev_addr->data[0]);
 281                 result = -EINVAL;
 282                 goto error_resp_parse;
 283         }
 284         if (wss == NULL) {
 285                 /* Discovery */
 286                 result = wlp_parse_d2_frame_to_cache(wlp, skb, neighbor);
 287                 if (result < 0) {
 288                         dev_err(dev, "WLP: Unable to parse D2 message from "
 289                                 "neighbor %02x:%02x for discovery.\n",
 290                                 dev_addr->data[1], dev_addr->data[0]);
 291                         goto error_resp_parse;
 292                 }
 293         } else {
 294                 /* Enrollment */
 295                 result = wlp_parse_d2_frame_to_enroll(wss, skb, neighbor,
 296                                                       wssid);
 297                 if (result < 0) {
 298                         dev_err(dev, "WLP: Unable to parse D2 message from "
 299                                 "neighbor %02x:%02x for enrollment.\n",
 300                                 dev_addr->data[1], dev_addr->data[0]);
 301                         goto error_resp_parse;
 302                 }
 303         }
 304 error_resp_parse:
 305         kfree_skb(skb);
 306 error_session:
 307         wlp->session = NULL;
 308 out:
 309         mutex_unlock(&wlp->mutex);
 310         return result;
 311 }
 312
 313 /**
 314  * Enroll into WSS of provided WSSID by using neighbor as registrar
 315  *
 316  * &wss->mutex is held
 317  */
 318 int wlp_enroll_neighbor(struct wlp *wlp, struct wlp_neighbor_e *neighbor,
 319                         struct wlp_wss *wss, struct wlp_uuid *wssid)
 320 {
 321         int result = 0;
 322         struct device *dev = &wlp->rc->uwb_dev.dev;
 323         char buf[WLP_WSS_UUID_STRSIZE];
 324         struct uwb_dev_addr *dev_addr = &neighbor->uwb_dev->dev_addr;
 325
 326         wlp_wss_uuid_print(buf, sizeof(buf), wssid);
 327
 328         result =  wlp_d1d2_exchange(wlp, neighbor, wss, wssid);
 329         if (result < 0) {
 330                 dev_err(dev, "WLP: D1/D2 message exchange for enrollment "
 331                         "failed. result = %d \n", result);
 332                 goto out;
 333         }
 334         if (wss->state != WLP_WSS_STATE_PART_ENROLLED) {
 335                 dev_err(dev, "WLP: Unable to enroll into WSS %s using "
 336                         "neighbor %02x:%02x. \n", buf,
 337                         dev_addr->data[1], dev_addr->data[0]);
 338                 result = -EINVAL;
 339                 goto out;
 340         }
 341         if (wss->secure_status == WLP_WSS_SECURE) {
 342                 dev_err(dev, "FIXME: need to complete secure enrollment.\n");
 343                 result = -EINVAL;
 344                 goto error;
 345         } else {
 346                 wss->state = WLP_WSS_STATE_ENROLLED;
 347                 dev_dbg(dev, "WLP: Success Enrollment into unsecure WSS "
 348                         "%s using neighbor %02x:%02x. \n",
 349                         buf, dev_addr->data[1], dev_addr->data[0]);
 350         }
 351 out:
 352         return result;
 353 error:
 354         wlp_wss_reset(wss);
 355         return result;
 356 }
 357
 358 /**
 359  * Discover WSS information of neighbor's active WSS
 360  */
 361 static
 362 int wlp_discover_neighbor(struct wlp *wlp,
 363                           struct wlp_neighbor_e *neighbor)
 364 {
 365         return wlp_d1d2_exchange(wlp, neighbor, NULL, NULL);
 366 }
 367
 368
 369 /**
 370  * Each neighbor in the neighborhood cache is discoverable. Discover it.
 371  *
 372  * Discovery is done through sending of D1 association frame and parsing
 373  * the D2 association frame response. Only wssid from D2 will be included
 374  * in neighbor cache, rest is just displayed to user and forgotten.
 375  *
 376  * The discovery is not done in parallel. This is simple and enables us to
 377  * maintain only one association context.
 378  *
 379  * The discovery of one neighbor does not affect the other, but if the
 380  * discovery of a neighbor fails it is removed from the neighborhood cache.
 381  */
 382 static
 383 int wlp_discover_all_neighbors(struct wlp *wlp)
 384 {
 385         int result = 0;
 386         struct device *dev = &wlp->rc->uwb_dev.dev;
 387         struct wlp_neighbor_e *neighbor, *next;
 388
 389         list_for_each_entry_safe(neighbor, next, &wlp->neighbors, node) {
 390                 result = wlp_discover_neighbor(wlp, neighbor);
 391                 if (result < 0) {
 392                         dev_err(dev, "WLP: Unable to discover neighbor "
 393                                 "%02x:%02x, removing from neighborhood. \n",
 394                                 neighbor->uwb_dev->dev_addr.data[1],
 395                                 neighbor->uwb_dev->dev_addr.data[0]);
 396                         __wlp_neighbor_release(neighbor);
 397                 }
 398         }
 399         return result;
 400 }
 401
 402 static int wlp_add_neighbor_helper(struct device *dev, void *priv)
 403 {
 404         struct wlp *wlp = priv;
 405         struct uwb_dev *uwb_dev = to_uwb_dev(dev);
 406
 407         return wlp_add_neighbor(wlp, uwb_dev);
 408 }
 409
 410 /**
 411  * Discover WLP neighborhood
 412  *
 413  * Will send D1 association frame to all devices in beacon group that have
 414  * discoverable bit set in WLP IE. D2 frames will be received, information
 415  * displayed to user in @buf. Partial information (from D2 association
 416  * frame) will be cached to assist with future association
 417  * requests.
 418  *
 419  * The discovery of the WLP neighborhood is triggered by the user. This
 420  * should occur infrequently and we thus free current cache and re-allocate
 421  * memory if needed.
 422  *
 423  * If one neighbor fails during initial discovery (determining if it is a
 424  * neighbor or not), we fail all - note that interaction with neighbor has
 425  * not occured at this point so if a failure occurs we know something went wrong
 426  * locally. We thus undo everything.
 427  */
 428 ssize_t wlp_discover(struct wlp *wlp)
 429 {
 430         int result = 0;
 431         struct device *dev = &wlp->rc->uwb_dev.dev;
 432
 433         mutex_lock(&wlp->nbmutex);
 434         /* Clear current neighborhood cache. */
 435         __wlp_neighbors_release(wlp);
 436         /* Determine which devices in neighborhood. Repopulate cache. */
 437         result = uwb_dev_for_each(wlp->rc, wlp_add_neighbor_helper, wlp);
 438         if (result < 0) {
 439                 /* May have partial neighbor information, release all. */
 440                 __wlp_neighbors_release(wlp);
 441                 goto error_dev_for_each;
 442         }
 443         /* Discover the properties of devices in neighborhood. */
 444         result = wlp_discover_all_neighbors(wlp);
 445         /* In case of failure we still print our partial results. */
 446         if (result < 0) {
 447                 dev_err(dev, "Unable to fully discover neighborhood. \n");
 448                 result = 0;
 449         }
 450 error_dev_for_each:
 451         mutex_unlock(&wlp->nbmutex);
 452         return result;
 453 }
 454
 455 /**
 456  * Handle events from UWB stack
 457  *
 458  * We handle events conservatively. If a neighbor goes off the air we
 459  * remove it from the neighborhood. If an association process is in
 460  * progress this function will block waiting for the nbmutex to become
 461  * free. The association process will thus be allowed to complete before it
 462  * is removed.
 463  */
 464 static
 465 void wlp_uwb_notifs_cb(void *_wlp, struct uwb_dev *uwb_dev,
 466                        enum uwb_notifs event)
 467 {
 468         struct wlp *wlp = _wlp;
 469         struct device *dev = &wlp->rc->uwb_dev.dev;
 470         struct wlp_neighbor_e *neighbor, *next;
 471         int result;
 472         switch (event) {
 473         case UWB_NOTIF_ONAIR:
 474                 result = wlp_eda_create_node(&wlp->eda,
 475                                              uwb_dev->mac_addr.data,
 476                                              &uwb_dev->dev_addr);
 477                 if (result < 0)
 478                         dev_err(dev, "WLP: Unable to add new neighbor "
 479                                 "%02x:%02x to EDA cache.\n",
 480                                 uwb_dev->dev_addr.data[1],
 481                                 uwb_dev->dev_addr.data[0]);
 482                 break;
 483         case UWB_NOTIF_OFFAIR:
 484                 wlp_eda_rm_node(&wlp->eda, &uwb_dev->dev_addr);
 485                 mutex_lock(&wlp->nbmutex);
 486                 list_for_each_entry_safe(neighbor, next, &wlp->neighbors, node) {
 487                         if (neighbor->uwb_dev == uwb_dev)
 488                                 __wlp_neighbor_release(neighbor);
 489                 }
 490                 mutex_unlock(&wlp->nbmutex);
 491                 break;
 492         default:
 493                 dev_err(dev, "don't know how to handle event %d from uwb\n",
 494                                 event);
 495         }
 496 }
 497
 498 static void wlp_channel_changed(struct uwb_pal *pal, int channel)
 499 {
 500         struct wlp *wlp = container_of(pal, struct wlp, pal);
 501
 502         if (channel < 0)
 503                 netif_carrier_off(wlp->ndev);
 504         else
 505                 netif_carrier_on(wlp->ndev);
 506 }
 507
 508 int wlp_setup(struct wlp *wlp, struct uwb_rc *rc, struct net_device *ndev)
 509 {
 510         int result;
 511
 512         BUG_ON(wlp->fill_device_info == NULL);
 513         BUG_ON(wlp->xmit_frame == NULL);
 514         BUG_ON(wlp->stop_queue == NULL);
 515         BUG_ON(wlp->start_queue == NULL);
 516
 517         wlp->rc = rc;
 518         wlp->ndev = ndev;
 519         wlp_eda_init(&wlp->eda);/* Set up address cache */
 520         wlp->uwb_notifs_handler.cb = wlp_uwb_notifs_cb;
 521         wlp->uwb_notifs_handler.data = wlp;
 522         uwb_notifs_register(rc, &wlp->uwb_notifs_handler);
 523
 524         uwb_pal_init(&wlp->pal);
 525         wlp->pal.rc = rc;
 526         wlp->pal.channel_changed = wlp_channel_changed;
 527         result = uwb_pal_register(&wlp->pal);
 528         if (result < 0)
 529                 uwb_notifs_deregister(wlp->rc, &wlp->uwb_notifs_handler);
 530
 531         return result;
 532 }
 533 EXPORT_SYMBOL_GPL(wlp_setup);
 534
 535 void wlp_remove(struct wlp *wlp)
 536 {
 537         wlp_neighbors_release(wlp);
 538         uwb_pal_unregister(&wlp->pal);
 539         uwb_notifs_deregister(wlp->rc, &wlp->uwb_notifs_handler);
 540         wlp_eda_release(&wlp->eda);
 541         mutex_lock(&wlp->mutex);
 542         if (wlp->dev_info != NULL)
 543                 kfree(wlp->dev_info);
 544         mutex_unlock(&wlp->mutex);
 545         wlp->rc = NULL;
 546 }
 547 EXPORT_SYMBOL_GPL(wlp_remove);
 548
 549 /**
 550  * wlp_reset_all - reset the WLP hardware
 551  * @wlp: the WLP device to reset.
 552  *
 553  * This schedules a full hardware reset of the WLP device.  The radio
 554  * controller and any other PALs will also be reset.
 555  */
 556 void wlp_reset_all(struct wlp *wlp)
 557 {
 558         uwb_rc_reset_all(wlp->rc);
 559 }
 560 EXPORT_SYMBOL_GPL(wlp_reset_all);