drivers/uwb/wlp/eda.c

   1 /*
   2  * WUSB Wire Adapter: WLP interface
   3  * Ethernet to device address cache
   4  *
   5  * Copyright (C) 2005-2006 Intel Corporation
   6  * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License version
  10  * 2 as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  20  * 02110-1301, USA.
  21  *
  22  *
  23  * We need to be able to map ethernet addresses to device addresses
  24  * and back because there is not explicit relationship between the eth
  25  * addresses used in the ETH frames and the device addresses (no, it
  26  * would not have been simpler to force as ETH address the MBOA MAC
  27  * address...no, not at all :).
  28  *
  29  * A device has one MBOA MAC address and one device address. It is possible
  30  * for a device to have more than one virtual MAC address (although a
  31  * virtual address can be the same as the MBOA MAC address). The device
  32  * address is guaranteed to be unique among the devices in the extended
  33  * beacon group (see ECMA 17.1.1). We thus use the device address as index
  34  * to this cache. We do allow searching based on virtual address as this
  35  * is how Ethernet frames will be addressed.
  36  *
  37  * We need to support virtual EUI-48. Although, right now the virtual
  38  * EUI-48 will always be the same as the MAC SAP address. The EDA cache
  39  * entry thus contains a MAC SAP address as well as the virtual address
  40  * (used to map the network stack address to a neighbor). When we move
  41  * to support more than one virtual MAC on a host then this organization
  42  * will have to change. Perhaps a neighbor has a list of WSSs, each with a
  43  * tag and virtual EUI-48.
  44  *
  45  * On data transmission
  46  * it is used to determine if the neighbor is connected and what WSS it
  47  * belongs to. With this we know what tag to add to the WLP frame. Storing
  48  * the WSS in the EDA cache may be overkill because we only support one
  49  * WSS. Hopefully we will support more than one WSS at some point.
  50  * On data reception it is used to determine the WSS based on
  51  * the tag and address of the transmitting neighbor.
  52  */
  53
  54 #include <linux/netdevice.h>
  55 #include <linux/etherdevice.h>
  56 #include <linux/wlp.h>
  57 #include "wlp-internal.h"
  58
  59
  60 /* FIXME: cache is not purged, only on device close */
  61
  62 /* FIXME: does not scale, change to dynamic array */
  63
  64 /*
  65  * Initialize the EDA cache
  66  *
  67  * @returns 0 if ok, < 0 errno code on error
  68  *
  69  * Call when the interface is being brought up
  70  *
  71  * NOTE: Keep it as a separate function as the implementation will
  72  *       change and be more complex.
  73  */
  74 void wlp_eda_init(struct wlp_eda *eda)
  75 {
  76         INIT_LIST_HEAD(&eda->cache);
  77         spin_lock_init(&eda->lock);
  78 }
  79
  80 /*
  81  * Release the EDA cache
  82  *
  83  * @returns 0 if ok, < 0 errno code on error
  84  *
  85  * Called when the interface is brought down
  86  */
  87 void wlp_eda_release(struct wlp_eda *eda)
  88 {
  89         unsigned long flags;
  90         struct wlp_eda_node *itr, *next;
  91
  92         spin_lock_irqsave(&eda->lock, flags);
  93         list_for_each_entry_safe(itr, next, &eda->cache, list_node) {
  94                 list_del(&itr->list_node);
  95                 kfree(itr);
  96         }
  97         spin_unlock_irqrestore(&eda->lock, flags);
  98 }
  99
 100 /*
 101  * Add an address mapping
 102  *
 103  * @returns 0 if ok, < 0 errno code on error
 104  *
 105  * An address mapping is initially created when the neighbor device is seen
 106  * for the first time (it is "onair"). At this time the neighbor is not
 107  * connected or associated with a WSS so we only populate the Ethernet and
 108  * Device address fields.
 109  *
 110  */
 111 int wlp_eda_create_node(struct wlp_eda *eda,
 112                         const unsigned char eth_addr[ETH_ALEN],
 113                         const struct uwb_dev_addr *dev_addr)
 114 {
 115         int result = 0;
 116         struct wlp_eda_node *itr;
 117         unsigned long flags;
 118
 119         BUG_ON(dev_addr == NULL || eth_addr == NULL);
 120         spin_lock_irqsave(&eda->lock, flags);
 121         list_for_each_entry(itr, &eda->cache, list_node) {
 122                 if (!memcmp(&itr->dev_addr, dev_addr, sizeof(itr->dev_addr))) {
 123                         printk(KERN_ERR "EDA cache already contains entry "
 124                                "for neighbor %02x:%02x\n",
 125                                dev_addr->data[1], dev_addr->data[0]);
 126                         result = -EEXIST;
 127                         goto out_unlock;
 128                 }
 129         }
 130         itr = kzalloc(sizeof(*itr), GFP_ATOMIC);
 131         if (itr != NULL) {
 132                 memcpy(itr->eth_addr, eth_addr, sizeof(itr->eth_addr));
 133                 itr->dev_addr = *dev_addr;
 134                 list_add(&itr->list_node, &eda->cache);
 135         } else
 136                 result = -ENOMEM;
 137 out_unlock:
 138         spin_unlock_irqrestore(&eda->lock, flags);
 139         return result;
 140 }
 141
 142 /*
 143  * Remove entry from EDA cache
 144  *
 145  * This is done when the device goes off air.
 146  */
 147 void wlp_eda_rm_node(struct wlp_eda *eda, const struct uwb_dev_addr *dev_addr)
 148 {
 149         struct wlp_eda_node *itr, *next;
 150         unsigned long flags;
 151
 152         spin_lock_irqsave(&eda->lock, flags);
 153         list_for_each_entry_safe(itr, next, &eda->cache, list_node) {
 154                 if (!memcmp(&itr->dev_addr, dev_addr, sizeof(itr->dev_addr))) {
 155                         list_del(&itr->list_node);
 156                         kfree(itr);
 157                         break;
 158                 }
 159         }
 160         spin_unlock_irqrestore(&eda->lock, flags);
 161 }
 162
 163 /*
 164  * Update an address mapping
 165  *
 166  * @returns 0 if ok, < 0 errno code on error
 167  */
 168 int wlp_eda_update_node(struct wlp_eda *eda,
 169                         const struct uwb_dev_addr *dev_addr,
 170                         struct wlp_wss *wss,
 171                         const unsigned char virt_addr[ETH_ALEN],
 172                         const u8 tag, const enum wlp_wss_connect state)
 173 {
 174         int result = -ENOENT;
 175         struct wlp_eda_node *itr;
 176         unsigned long flags;
 177
 178         spin_lock_irqsave(&eda->lock, flags);
 179         list_for_each_entry(itr, &eda->cache, list_node) {
 180                 if (!memcmp(&itr->dev_addr, dev_addr, sizeof(itr->dev_addr))) {
 181                         /* Found it, update it */
 182                         itr->wss = wss;
 183                         memcpy(itr->virt_addr, virt_addr,
 184                                sizeof(itr->virt_addr));
 185                         itr->tag = tag;
 186                         itr->state = state;
 187                         result = 0;
 188                         goto out_unlock;
 189                 }
 190         }
 191         /* Not found */
 192 out_unlock:
 193         spin_unlock_irqrestore(&eda->lock, flags);
 194         return result;
 195 }
 196
 197 /*
 198  * Update only state field of an address mapping
 199  *
 200  * @returns 0 if ok, < 0 errno code on error
 201  */
 202 int wlp_eda_update_node_state(struct wlp_eda *eda,
 203                               const struct uwb_dev_addr *dev_addr,
 204                               const enum wlp_wss_connect state)
 205 {
 206         int result = -ENOENT;
 207         struct wlp_eda_node *itr;
 208         unsigned long flags;
 209
 210         spin_lock_irqsave(&eda->lock, flags);
 211         list_for_each_entry(itr, &eda->cache, list_node) {
 212                 if (!memcmp(&itr->dev_addr, dev_addr, sizeof(itr->dev_addr))) {
 213                         /* Found it, update it */
 214                         itr->state = state;
 215                         result = 0;
 216                         goto out_unlock;
 217                 }
 218         }
 219         /* Not found */
 220 out_unlock:
 221         spin_unlock_irqrestore(&eda->lock, flags);
 222         return result;
 223 }
 224
 225 /*
 226  * Return contents of EDA cache entry
 227  *
 228  * @dev_addr: index to EDA cache
 229  * @eda_entry: pointer to where contents of EDA cache will be copied
 230  */
 231 int wlp_copy_eda_node(struct wlp_eda *eda, struct uwb_dev_addr *dev_addr,
 232                       struct wlp_eda_node *eda_entry)
 233 {
 234         int result = -ENOENT;
 235         struct wlp_eda_node *itr;
 236         unsigned long flags;
 237
 238         spin_lock_irqsave(&eda->lock, flags);
 239         list_for_each_entry(itr, &eda->cache, list_node) {
 240                 if (!memcmp(&itr->dev_addr, dev_addr, sizeof(itr->dev_addr))) {
 241                         *eda_entry = *itr;
 242                         result = 0;
 243                         goto out_unlock;
 244                 }
 245         }
 246         /* Not found */
 247 out_unlock:
 248         spin_unlock_irqrestore(&eda->lock, flags);
 249         return result;
 250 }
 251
 252 /*
 253  * Execute function for every element in the cache
 254  *
 255  * @function: function to execute on element of cache (must be atomic)
 256  * @priv:     private data of function
 257  * @returns:  result of first function that failed, or last function
 258  *            executed if no function failed.
 259  *
 260  * Stop executing when function returns error for any element in cache.
 261  *
 262  * IMPORTANT: We are using a spinlock here: the function executed on each
 263  * element has to be atomic.
 264  */
 265 int wlp_eda_for_each(struct wlp_eda *eda, wlp_eda_for_each_f function,
 266                      void *priv)
 267 {
 268         int result = 0;
 269         struct wlp *wlp = container_of(eda, struct wlp, eda);
 270         struct wlp_eda_node *entry;
 271         unsigned long flags;
 272
 273         spin_lock_irqsave(&eda->lock, flags);
 274         list_for_each_entry(entry, &eda->cache, list_node) {
 275                 result = (*function)(wlp, entry, priv);
 276                 if (result < 0)
 277                         break;
 278         }
 279         spin_unlock_irqrestore(&eda->lock, flags);
 280         return result;
 281 }
 282
 283 /*
 284  * Execute function for single element in the cache (return dev addr)
 285  *
 286  * @virt_addr: index into EDA cache used to determine which element to
 287  *             execute the function on
 288  * @dev_addr: device address of element in cache will be returned using
 289  *            @dev_addr
 290  * @function: function to execute on element of cache (must be atomic)
 291  * @priv:     private data of function
 292  * @returns:  result of function
 293  *
 294  * IMPORTANT: We are using a spinlock here: the function executed on the
 295  * element has to be atomic.
 296  */
 297 int wlp_eda_for_virtual(struct wlp_eda *eda,
 298                         const unsigned char virt_addr[ETH_ALEN],
 299                         struct uwb_dev_addr *dev_addr,
 300                         wlp_eda_for_each_f function,
 301                         void *priv)
 302 {
 303         int result = 0;
 304         struct wlp *wlp = container_of(eda, struct wlp, eda);
 305         struct wlp_eda_node *itr;
 306         unsigned long flags;
 307         int found = 0;
 308
 309         spin_lock_irqsave(&eda->lock, flags);
 310         list_for_each_entry(itr, &eda->cache, list_node) {
 311                 if (!memcmp(itr->virt_addr, virt_addr,
 312                            sizeof(itr->virt_addr))) {
 313                         result = (*function)(wlp, itr, priv);
 314                         *dev_addr = itr->dev_addr;
 315                         found = 1;
 316                         break;
 317                 }
 318         }
 319         if (!found)
 320                 result = -ENODEV;
 321         spin_unlock_irqrestore(&eda->lock, flags);
 322         return result;
 323 }
 324
 325 static const char *__wlp_wss_connect_state[] = { "WLP_WSS_UNCONNECTED",
 326                                           "WLP_WSS_CONNECTED",
 327                                           "WLP_WSS_CONNECT_FAILED",
 328 };
 329
 330 static const char *wlp_wss_connect_state_str(unsigned id)
 331 {
 332         if (id >= ARRAY_SIZE(__wlp_wss_connect_state))
 333                 return "unknown WSS connection state";
 334         return __wlp_wss_connect_state[id];
 335 }
 336
 337 /*
 338  * View EDA cache from user space
 339  *
 340  * A debugging feature to give user visibility into the EDA cache. Also
 341  * used to display members of WSS to user (called from wlp_wss_members_show())
 342  */
 343 ssize_t wlp_eda_show(struct wlp *wlp, char *buf)
 344 {
 345         ssize_t result = 0;
 346         struct wlp_eda_node *entry;
 347         unsigned long flags;
 348         struct wlp_eda *eda = &wlp->eda;
 349         spin_lock_irqsave(&eda->lock, flags);
 350         result = scnprintf(buf, PAGE_SIZE, "#eth_addr dev_addr wss_ptr "
 351                            "tag state virt_addr\n");
 352         list_for_each_entry(entry, &eda->cache, list_node) {
 353                 result += scnprintf(buf + result, PAGE_SIZE - result,
 354                                     "%pM %02x:%02x %p 0x%02x %s %pM\n",
 355                                     entry->eth_addr,
 356                                     entry->dev_addr.data[1],
 357                                     entry->dev_addr.data[0], entry->wss,
 358                                     entry->tag,
 359                                     wlp_wss_connect_state_str(entry->state),
 360                                     entry->virt_addr);
 361                 if (result >= PAGE_SIZE)
 362                         break;
 363         }
 364         spin_unlock_irqrestore(&eda->lock, flags);
 365         return result;
 366 }
 367 EXPORT_SYMBOL_GPL(wlp_eda_show);
 368
 369 /*
 370  * Add new EDA cache entry based on user input in sysfs
 371  *
 372  * Should only be used for debugging.
 373  *
 374  * The WSS is assumed to be the only WSS supported. This needs to be
 375  * redesigned when we support more than one WSS.
 376  */
 377 ssize_t wlp_eda_store(struct wlp *wlp, const char *buf, size_t size)
 378 {
 379         ssize_t result;
 380         struct wlp_eda *eda = &wlp->eda;
 381         u8 eth_addr[6];
 382         struct uwb_dev_addr dev_addr;
 383         u8 tag;
 384         unsigned state;
 385
 386         result = sscanf(buf, "%02hhx:%02hhx:%02hhx:%02hhx:%02hhx:%02hhx "
 387                         "%02hhx:%02hhx %02hhx %u\n",
 388                         &eth_addr[0], &eth_addr[1],
 389                         &eth_addr[2], &eth_addr[3],
 390                         &eth_addr[4], &eth_addr[5],
 391                         &dev_addr.data[1], &dev_addr.data[0], &tag, &state);
 392         switch (result) {
 393         case 6: /* no dev addr specified -- remove entry NOT IMPLEMENTED */
 394                 /*result = wlp_eda_rm(eda, eth_addr, &dev_addr);*/
 395                 result = -ENOSYS;
 396                 break;
 397         case 10:
 398                 state = state >= 1 ? 1 : 0;
 399                 result = wlp_eda_create_node(eda, eth_addr, &dev_addr);
 400                 if (result < 0 && result != -EEXIST)
 401                         goto error;
 402                 /* Set virtual addr to be same as MAC */
 403                 result = wlp_eda_update_node(eda, &dev_addr, &wlp->wss,
 404                                              eth_addr, tag, state);
 405                 if (result < 0)
 406                         goto error;
 407                 break;
 408         default: /* bad format */
 409                 result = -EINVAL;
 410         }
 411 error:
 412         return result < 0 ? result : size;
 413 }
 414 EXPORT_SYMBOL_GPL(wlp_eda_store);