net/irda/discovery.c

   1 /*********************************************************************
   2  *
   3  * Filename:      discovery.c
   4  * Version:       0.1
   5  * Description:   Routines for handling discoveries at the IrLMP layer
   6  * Status:        Experimental.
   7  * Author:        Dag Brattli <dagb@cs.uit.no>
   8  * Created at:    Tue Apr  6 15:33:50 1999
   9  * Modified at:   Sat Oct  9 17:11:31 1999
  10  * Modified by:   Dag Brattli <dagb@cs.uit.no>
  11  * Modified at:   Fri May 28  3:11 CST 1999
  12  * Modified by:   Horst von Brand <vonbrand@sleipnir.valparaiso.cl>
  13  *
  14  *     Copyright (c) 1999 Dag Brattli, All Rights Reserved.
  15  *
  16  *     This program is free software; you can redistribute it and/or
  17  *     modify it under the terms of the GNU General Public License as
  18  *     published by the Free Software Foundation; either version 2 of
  19  *     the License, or (at your option) any later version.
  20  *
  21  *     This program is distributed in the hope that it will be useful,
  22  *     but WITHOUT ANY WARRANTY; without even the implied warranty of
  23  *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  24  *     GNU General Public License for more details.
  25  *
  26  *     You should have received a copy of the GNU General Public License
  27  *     along with this program; if not, write to the Free Software
  28  *     Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  29  *     MA 02111-1307 USA
  30  *
  31  ********************************************************************/
  32
  33 #include <linux/string.h>
  34 #include <linux/socket.h>
  35 #include <linux/seq_file.h>
  36
  37 #include <net/irda/irda.h>
  38 #include <net/irda/irlmp.h>
  39
  40 #include <net/irda/discovery.h>
  41
  42 /*
  43  * Function irlmp_add_discovery (cachelog, discovery)
  44  *
  45  *    Add a new discovery to the cachelog, and remove any old discoveries
  46  *    from the same device
  47  *
  48  * Note : we try to preserve the time this device was *first* discovered
  49  * (as opposed to the time of last discovery used for cleanup). This is
  50  * used by clients waiting for discovery events to tell if the device
  51  * discovered is "new" or just the same old one. They can't rely there
  52  * on a binary flag (new/old), because not all discovery events are
  53  * propagated to them, and they might not always listen, so they would
  54  * miss some new devices popping up...
  55  * Jean II
  56  */
  57 void irlmp_add_discovery(hashbin_t *cachelog, discovery_t *new)
  58 {
  59         discovery_t *discovery, *node;
  60         unsigned long flags;
  61
  62         /* Set time of first discovery if node is new (see below) */
  63         new->firststamp = new->timestamp;
  64
  65         spin_lock_irqsave(&cachelog->hb_spinlock, flags);
  66
  67         /*
  68          * Remove all discoveries of devices that has previously been
  69          * discovered on the same link with the same name (info), or the
  70          * same daddr. We do this since some devices (mostly PDAs) change
  71          * their device address between every discovery.
  72          */
  73         discovery = (discovery_t *) hashbin_get_first(cachelog);
  74         while (discovery != NULL ) {
  75                 node = discovery;
  76
  77                 /* Be sure to stay one item ahead */
  78                 discovery = (discovery_t *) hashbin_get_next(cachelog);
  79
  80                 if ((node->data.saddr == new->data.saddr) &&
  81                     ((node->data.daddr == new->data.daddr) ||
  82                      (strcmp(node->data.info, new->data.info) == 0)))
  83                 {
  84                         /* This discovery is a previous discovery
  85                          * from the same device, so just remove it
  86                          */
  87                         hashbin_remove_this(cachelog, (irda_queue_t *) node);
  88                         /* Check if hints bits are unchanged */
  89                         if(u16ho(node->data.hints) == u16ho(new->data.hints))
  90                                 /* Set time of first discovery for this node */
  91                                 new->firststamp = node->firststamp;
  92                         kfree(node);
  93                 }
  94         }
  95
  96         /* Insert the new and updated version */
  97         hashbin_insert(cachelog, (irda_queue_t *) new, new->data.daddr, NULL);
  98
  99         spin_unlock_irqrestore(&cachelog->hb_spinlock, flags);
 100 }
 101
 102 /*
 103  * Function irlmp_add_discovery_log (cachelog, log)
 104  *
 105  *    Merge a disovery log into the cachelog.
 106  *
 107  */
 108 void irlmp_add_discovery_log(hashbin_t *cachelog, hashbin_t *log)
 109 {
 110         discovery_t *discovery;
 111
 112         IRDA_DEBUG(4, "%s()\n", __FUNCTION__);
 113
 114         /*
 115          *  If log is missing this means that IrLAP was unable to perform the
 116          *  discovery, so restart discovery again with just the half timeout
 117          *  of the normal one.
 118          */
 119         /* Well... It means that there was nobody out there - Jean II */
 120         if (log == NULL) {
 121                 /* irlmp_start_discovery_timer(irlmp, 150); */
 122                 return;
 123         }
 124
 125         /*
 126          * Locking : we are the only owner of this discovery log, so
 127          * no need to lock it.
 128          * We just need to lock the global log in irlmp_add_discovery().
 129          */
 130         discovery = (discovery_t *) hashbin_remove_first(log);
 131         while (discovery != NULL) {
 132                 irlmp_add_discovery(cachelog, discovery);
 133
 134                 discovery = (discovery_t *) hashbin_remove_first(log);
 135         }
 136
 137         /* Delete the now empty log */
 138         hashbin_delete(log, (FREE_FUNC) kfree);
 139 }
 140
 141 /*
 142  * Function irlmp_expire_discoveries (log, saddr, force)
 143  *
 144  *    Go through all discoveries and expire all that has stayed too long
 145  *
 146  * Note : this assume that IrLAP won't change its saddr, which
 147  * currently is a valid assumption...
 148  */
 149 void irlmp_expire_discoveries(hashbin_t *log, __u32 saddr, int force)
 150 {
 151         discovery_t *           discovery;
 152         discovery_t *           curr;
 153         unsigned long           flags;
 154         discinfo_t *            buffer = NULL;
 155         int                     n;              /* Size of the full log */
 156         int                     i = 0;          /* How many we expired */
 157
 158         IRDA_ASSERT(log != NULL, return;);
 159         IRDA_DEBUG(4, "%s()\n", __FUNCTION__);
 160
 161         spin_lock_irqsave(&log->hb_spinlock, flags);
 162
 163         discovery = (discovery_t *) hashbin_get_first(log);
 164         while (discovery != NULL) {
 165                 /* Be sure to be one item ahead */
 166                 curr = discovery;
 167                 discovery = (discovery_t *) hashbin_get_next(log);
 168
 169                 /* Test if it's time to expire this discovery */
 170                 if ((curr->data.saddr == saddr) &&
 171                     (force ||
 172                      ((jiffies - curr->timestamp) > DISCOVERY_EXPIRE_TIMEOUT)))
 173                 {
 174                         /* Create buffer as needed.
 175                          * As this function get called a lot and most time
 176                          * we don't have anything to put in the log (we are
 177                          * quite picky), we can save a lot of overhead
 178                          * by not calling kmalloc. Jean II */
 179                         if(buffer == NULL) {
 180                                 /* Create the client specific buffer */
 181                                 n = HASHBIN_GET_SIZE(log);
 182                                 buffer = kmalloc(n * sizeof(struct irda_device_info), GFP_ATOMIC);
 183                                 if (buffer == NULL) {
 184                                         spin_unlock_irqrestore(&log->hb_spinlock, flags);
 185                                         return;
 186                                 }
 187
 188                         }
 189
 190                         /* Copy discovery information */
 191                         memcpy(&(buffer[i]), &(curr->data),
 192                                sizeof(discinfo_t));
 193                         i++;
 194
 195                         /* Remove it from the log */
 196                         curr = hashbin_remove_this(log, (irda_queue_t *) curr);
 197                         kfree(curr);
 198                 }
 199         }
 200
 201         /* Drop the spinlock before calling the higher layers, as
 202          * we can't guarantee they won't call us back and create a
 203          * deadlock. We will work on our own private data, so we
 204          * don't care to be interupted. - Jean II */
 205         spin_unlock_irqrestore(&log->hb_spinlock, flags);
 206
 207         if(buffer == NULL)
 208                 return;
 209
 210         /* Tell IrLMP and registered clients about it */
 211         irlmp_discovery_expiry(buffer, i);
 212
 213         /* Free up our buffer */
 214         kfree(buffer);
 215 }
 216
 217 #if 0
 218 /*
 219  * Function irlmp_dump_discoveries (log)
 220  *
 221  *    Print out all discoveries in log
 222  *
 223  */
 224 void irlmp_dump_discoveries(hashbin_t *log)
 225 {
 226         discovery_t *discovery;
 227
 228         IRDA_ASSERT(log != NULL, return;);
 229
 230         discovery = (discovery_t *) hashbin_get_first(log);
 231         while (discovery != NULL) {
 232                 IRDA_DEBUG(0, "Discovery:\n");
 233                 IRDA_DEBUG(0, "  daddr=%08x\n", discovery->data.daddr);
 234                 IRDA_DEBUG(0, "  saddr=%08x\n", discovery->data.saddr);
 235                 IRDA_DEBUG(0, "  nickname=%s\n", discovery->data.info);
 236
 237                 discovery = (discovery_t *) hashbin_get_next(log);
 238         }
 239 }
 240 #endif
 241
 242 /*
 243  * Function irlmp_copy_discoveries (log, pn, mask)
 244  *
 245  *    Copy all discoveries in a buffer
 246  *
 247  * This function implement a safe way for lmp clients to access the
 248  * discovery log. The basic problem is that we don't want the log
 249  * to change (add/remove) while the client is reading it. If the
 250  * lmp client manipulate directly the hashbin, he is sure to get
 251  * into troubles...
 252  * The idea is that we copy all the current discovery log in a buffer
 253  * which is specific to the client and pass this copy to him. As we
 254  * do this operation with the spinlock grabbed, we are safe...
 255  * Note : we don't want those clients to grab the spinlock, because
 256  * we have no control on how long they will hold it...
 257  * Note : we choose to copy the log in "struct irda_device_info" to
 258  * save space...
 259  * Note : the client must kfree himself() the log...
 260  * Jean II
 261  */
 262 struct irda_device_info *irlmp_copy_discoveries(hashbin_t *log, int *pn,
 263                                                 __u16 mask, int old_entries)
 264 {
 265         discovery_t *           discovery;
 266         unsigned long           flags;
 267         discinfo_t *            buffer = NULL;
 268         int                     j_timeout = (sysctl_discovery_timeout * HZ);
 269         int                     n;              /* Size of the full log */
 270         int                     i = 0;          /* How many we picked */
 271
 272         IRDA_ASSERT(pn != NULL, return NULL;);
 273         IRDA_ASSERT(log != NULL, return NULL;);
 274
 275         /* Save spin lock */
 276         spin_lock_irqsave(&log->hb_spinlock, flags);
 277
 278         discovery = (discovery_t *) hashbin_get_first(log);
 279         while (discovery != NULL) {
 280                 /* Mask out the ones we don't want :
 281                  * We want to match the discovery mask, and to get only
 282                  * the most recent one (unless we want old ones) */
 283                 if ((u16ho(discovery->data.hints) & mask) &&
 284                     ((old_entries) ||
 285                      ((jiffies - discovery->firststamp) < j_timeout)) ) {
 286                         /* Create buffer as needed.
 287                          * As this function get called a lot and most time
 288                          * we don't have anything to put in the log (we are
 289                          * quite picky), we can save a lot of overhead
 290                          * by not calling kmalloc. Jean II */
 291                         if(buffer == NULL) {
 292                                 /* Create the client specific buffer */
 293                                 n = HASHBIN_GET_SIZE(log);
 294                                 buffer = kmalloc(n * sizeof(struct irda_device_info), GFP_ATOMIC);
 295                                 if (buffer == NULL) {
 296                                         spin_unlock_irqrestore(&log->hb_spinlock, flags);
 297                                         return NULL;
 298                                 }
 299
 300                         }
 301
 302                         /* Copy discovery information */
 303                         memcpy(&(buffer[i]), &(discovery->data),
 304                                sizeof(discinfo_t));
 305                         i++;
 306                 }
 307                 discovery = (discovery_t *) hashbin_get_next(log);
 308         }
 309
 310         spin_unlock_irqrestore(&log->hb_spinlock, flags);
 311
 312         /* Get the actual number of device in the buffer and return */
 313         *pn = i;
 314         return(buffer);
 315 }
 316
 317 #ifdef CONFIG_PROC_FS
 318 static inline discovery_t *discovery_seq_idx(loff_t pos)
 319
 320 {
 321         discovery_t *discovery;
 322
 323         for (discovery = (discovery_t *) hashbin_get_first(irlmp->cachelog);
 324              discovery != NULL;
 325              discovery = (discovery_t *) hashbin_get_next(irlmp->cachelog)) {
 326                 if (pos-- == 0)
 327                         break;
 328         }
 329
 330         return discovery;
 331 }
 332
 333 static void *discovery_seq_start(struct seq_file *seq, loff_t *pos)
 334 {
 335         spin_lock_irq(&irlmp->cachelog->hb_spinlock);
 336         return *pos ? discovery_seq_idx(*pos - 1) : SEQ_START_TOKEN;
 337 }
 338
 339 static void *discovery_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 340 {
 341         ++*pos;
 342         return (v == SEQ_START_TOKEN)
 343                 ? (void *) hashbin_get_first(irlmp->cachelog)
 344                 : (void *) hashbin_get_next(irlmp->cachelog);
 345 }
 346
 347 static void discovery_seq_stop(struct seq_file *seq, void *v)
 348 {
 349         spin_unlock_irq(&irlmp->cachelog->hb_spinlock);
 350 }
 351
 352 static int discovery_seq_show(struct seq_file *seq, void *v)
 353 {
 354         if (v == SEQ_START_TOKEN)
 355                 seq_puts(seq, "IrLMP: Discovery log:\n\n");
 356         else {
 357                 const discovery_t *discovery = v;
 358
 359                 seq_printf(seq, "nickname: %s, hint: 0x%02x%02x",
 360                            discovery->data.info,
 361                            discovery->data.hints[0],
 362                            discovery->data.hints[1]);
 363 #if 0
 364                 if ( discovery->data.hints[0] & HINT_PNP)
 365                         seq_puts(seq, "PnP Compatible ");
 366                 if ( discovery->data.hints[0] & HINT_PDA)
 367                         seq_puts(seq, "PDA/Palmtop ");
 368                 if ( discovery->data.hints[0] & HINT_COMPUTER)
 369                         seq_puts(seq, "Computer ");
 370                 if ( discovery->data.hints[0] & HINT_PRINTER)
 371                         seq_puts(seq, "Printer ");
 372                 if ( discovery->data.hints[0] & HINT_MODEM)
 373                         seq_puts(seq, "Modem ");
 374                 if ( discovery->data.hints[0] & HINT_FAX)
 375                         seq_puts(seq, "Fax ");
 376                 if ( discovery->data.hints[0] & HINT_LAN)
 377                         seq_puts(seq, "LAN Access ");
 378
 379                 if ( discovery->data.hints[1] & HINT_TELEPHONY)
 380                         seq_puts(seq, "Telephony ");
 381                 if ( discovery->data.hints[1] & HINT_FILE_SERVER)
 382                         seq_puts(seq, "File Server ");
 383                 if ( discovery->data.hints[1] & HINT_COMM)
 384                         seq_puts(seq, "IrCOMM ");
 385                 if ( discovery->data.hints[1] & HINT_OBEX)
 386                         seq_puts(seq, "IrOBEX ");
 387 #endif
 388                 seq_printf(seq,", saddr: 0x%08x, daddr: 0x%08x\n\n",
 389                                discovery->data.saddr,
 390                                discovery->data.daddr);
 391
 392                 seq_putc(seq, '\n');
 393         }
 394         return 0;
 395 }
 396
 397 static struct seq_operations discovery_seq_ops = {
 398         .start  = discovery_seq_start,
 399         .next   = discovery_seq_next,
 400         .stop   = discovery_seq_stop,
 401         .show   = discovery_seq_show,
 402 };
 403
 404 static int discovery_seq_open(struct inode *inode, struct file *file)
 405 {
 406         IRDA_ASSERT(irlmp != NULL, return -EINVAL;);
 407
 408         return seq_open(file, &discovery_seq_ops);
 409 }
 410
 411 struct file_operations discovery_seq_fops = {
 412         .owner          = THIS_MODULE,
 413         .open           = discovery_seq_open,
 414         .read           = seq_read,
 415         .llseek         = seq_lseek,
 416         .release        = seq_release,
 417 };
 418 #endif