linux/net/irda/discovery.c
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   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/fs.h>
  36#include <linux/seq_file.h>
  37#include <linux/slab.h>
  38#include <linux/export.h>
  39
  40#include <net/irda/irda.h>
  41#include <net/irda/irlmp.h>
  42
  43#include <net/irda/discovery.h>
  44
  45#include <asm/unaligned.h>
  46
  47/*
  48 * Function irlmp_add_discovery (cachelog, discovery)
  49 *
  50 *    Add a new discovery to the cachelog, and remove any old discoveries
  51 *    from the same device
  52 *
  53 * Note : we try to preserve the time this device was *first* discovered
  54 * (as opposed to the time of last discovery used for cleanup). This is
  55 * used by clients waiting for discovery events to tell if the device
  56 * discovered is "new" or just the same old one. They can't rely there
  57 * on a binary flag (new/old), because not all discovery events are
  58 * propagated to them, and they might not always listen, so they would
  59 * miss some new devices popping up...
  60 * Jean II
  61 */
  62void irlmp_add_discovery(hashbin_t *cachelog, discovery_t *new)
  63{
  64        discovery_t *discovery, *node;
  65        unsigned long flags;
  66
  67        /* Set time of first discovery if node is new (see below) */
  68        new->firststamp = new->timestamp;
  69
  70        spin_lock_irqsave(&cachelog->hb_spinlock, flags);
  71
  72        /*
  73         * Remove all discoveries of devices that has previously been
  74         * discovered on the same link with the same name (info), or the
  75         * same daddr. We do this since some devices (mostly PDAs) change
  76         * their device address between every discovery.
  77         */
  78        discovery = (discovery_t *) hashbin_get_first(cachelog);
  79        while (discovery != NULL ) {
  80                node = discovery;
  81
  82                /* Be sure to stay one item ahead */
  83                discovery = (discovery_t *) hashbin_get_next(cachelog);
  84
  85                if ((node->data.saddr == new->data.saddr) &&
  86                    ((node->data.daddr == new->data.daddr) ||
  87                     (strcmp(node->data.info, new->data.info) == 0)))
  88                {
  89                        /* This discovery is a previous discovery
  90                         * from the same device, so just remove it
  91                         */
  92                        hashbin_remove_this(cachelog, (irda_queue_t *) node);
  93                        /* Check if hints bits are unchanged */
  94                        if (get_unaligned((__u16 *)node->data.hints) == get_unaligned((__u16 *)new->data.hints))
  95                                /* Set time of first discovery for this node */
  96                                new->firststamp = node->firststamp;
  97                        kfree(node);
  98                }
  99        }
 100
 101        /* Insert the new and updated version */
 102        hashbin_insert(cachelog, (irda_queue_t *) new, new->data.daddr, NULL);
 103
 104        spin_unlock_irqrestore(&cachelog->hb_spinlock, flags);
 105}
 106
 107/*
 108 * Function irlmp_add_discovery_log (cachelog, log)
 109 *
 110 *    Merge a disovery log into the cachelog.
 111 *
 112 */
 113void irlmp_add_discovery_log(hashbin_t *cachelog, hashbin_t *log)
 114{
 115        discovery_t *discovery;
 116
 117        IRDA_DEBUG(4, "%s()\n", __func__);
 118
 119        /*
 120         *  If log is missing this means that IrLAP was unable to perform the
 121         *  discovery, so restart discovery again with just the half timeout
 122         *  of the normal one.
 123         */
 124        /* Well... It means that there was nobody out there - Jean II */
 125        if (log == NULL) {
 126                /* irlmp_start_discovery_timer(irlmp, 150); */
 127                return;
 128        }
 129
 130        /*
 131         * Locking : we are the only owner of this discovery log, so
 132         * no need to lock it.
 133         * We just need to lock the global log in irlmp_add_discovery().
 134         */
 135        discovery = (discovery_t *) hashbin_remove_first(log);
 136        while (discovery != NULL) {
 137                irlmp_add_discovery(cachelog, discovery);
 138
 139                discovery = (discovery_t *) hashbin_remove_first(log);
 140        }
 141
 142        /* Delete the now empty log */
 143        hashbin_delete(log, (FREE_FUNC) kfree);
 144}
 145
 146/*
 147 * Function irlmp_expire_discoveries (log, saddr, force)
 148 *
 149 *    Go through all discoveries and expire all that has stayed too long
 150 *
 151 * Note : this assume that IrLAP won't change its saddr, which
 152 * currently is a valid assumption...
 153 */
 154void irlmp_expire_discoveries(hashbin_t *log, __u32 saddr, int force)
 155{
 156        discovery_t *           discovery;
 157        discovery_t *           curr;
 158        unsigned long           flags;
 159        discinfo_t *            buffer = NULL;
 160        int                     n;              /* Size of the full log */
 161        int                     i = 0;          /* How many we expired */
 162
 163        IRDA_ASSERT(log != NULL, return;);
 164        IRDA_DEBUG(4, "%s()\n", __func__);
 165
 166        spin_lock_irqsave(&log->hb_spinlock, flags);
 167
 168        discovery = (discovery_t *) hashbin_get_first(log);
 169        while (discovery != NULL) {
 170                /* Be sure to be one item ahead */
 171                curr = discovery;
 172                discovery = (discovery_t *) hashbin_get_next(log);
 173
 174                /* Test if it's time to expire this discovery */
 175                if ((curr->data.saddr == saddr) &&
 176                    (force ||
 177                     ((jiffies - curr->timestamp) > DISCOVERY_EXPIRE_TIMEOUT)))
 178                {
 179                        /* Create buffer as needed.
 180                         * As this function get called a lot and most time
 181                         * we don't have anything to put in the log (we are
 182                         * quite picky), we can save a lot of overhead
 183                         * by not calling kmalloc. Jean II */
 184                        if(buffer == NULL) {
 185                                /* Create the client specific buffer */
 186                                n = HASHBIN_GET_SIZE(log);
 187                                buffer = kmalloc(n * sizeof(struct irda_device_info), GFP_ATOMIC);
 188                                if (buffer == NULL) {
 189                                        spin_unlock_irqrestore(&log->hb_spinlock, flags);
 190                                        return;
 191                                }
 192
 193                        }
 194
 195                        /* Copy discovery information */
 196                        memcpy(&(buffer[i]), &(curr->data),
 197                               sizeof(discinfo_t));
 198                        i++;
 199
 200                        /* Remove it from the log */
 201                        curr = hashbin_remove_this(log, (irda_queue_t *) curr);
 202                        kfree(curr);
 203                }
 204        }
 205
 206        /* Drop the spinlock before calling the higher layers, as
 207         * we can't guarantee they won't call us back and create a
 208         * deadlock. We will work on our own private data, so we
 209         * don't care to be interrupted. - Jean II */
 210        spin_unlock_irqrestore(&log->hb_spinlock, flags);
 211
 212        if(buffer == NULL)
 213                return;
 214
 215        /* Tell IrLMP and registered clients about it */
 216        irlmp_discovery_expiry(buffer, i);
 217
 218        /* Free up our buffer */
 219        kfree(buffer);
 220}
 221
 222#if 0
 223/*
 224 * Function irlmp_dump_discoveries (log)
 225 *
 226 *    Print out all discoveries in log
 227 *
 228 */
 229void irlmp_dump_discoveries(hashbin_t *log)
 230{
 231        discovery_t *discovery;
 232
 233        IRDA_ASSERT(log != NULL, return;);
 234
 235        discovery = (discovery_t *) hashbin_get_first(log);
 236        while (discovery != NULL) {
 237                IRDA_DEBUG(0, "Discovery:\n");
 238                IRDA_DEBUG(0, "  daddr=%08x\n", discovery->data.daddr);
 239                IRDA_DEBUG(0, "  saddr=%08x\n", discovery->data.saddr);
 240                IRDA_DEBUG(0, "  nickname=%s\n", discovery->data.info);
 241
 242                discovery = (discovery_t *) hashbin_get_next(log);
 243        }
 244}
 245#endif
 246
 247/*
 248 * Function irlmp_copy_discoveries (log, pn, mask)
 249 *
 250 *    Copy all discoveries in a buffer
 251 *
 252 * This function implement a safe way for lmp clients to access the
 253 * discovery log. The basic problem is that we don't want the log
 254 * to change (add/remove) while the client is reading it. If the
 255 * lmp client manipulate directly the hashbin, he is sure to get
 256 * into troubles...
 257 * The idea is that we copy all the current discovery log in a buffer
 258 * which is specific to the client and pass this copy to him. As we
 259 * do this operation with the spinlock grabbed, we are safe...
 260 * Note : we don't want those clients to grab the spinlock, because
 261 * we have no control on how long they will hold it...
 262 * Note : we choose to copy the log in "struct irda_device_info" to
 263 * save space...
 264 * Note : the client must kfree himself() the log...
 265 * Jean II
 266 */
 267struct irda_device_info *irlmp_copy_discoveries(hashbin_t *log, int *pn,
 268                                                __u16 mask, int old_entries)
 269{
 270        discovery_t *           discovery;
 271        unsigned long           flags;
 272        discinfo_t *            buffer = NULL;
 273        int                     j_timeout = (sysctl_discovery_timeout * HZ);
 274        int                     n;              /* Size of the full log */
 275        int                     i = 0;          /* How many we picked */
 276
 277        IRDA_ASSERT(pn != NULL, return NULL;);
 278        IRDA_ASSERT(log != NULL, return NULL;);
 279
 280        /* Save spin lock */
 281        spin_lock_irqsave(&log->hb_spinlock, flags);
 282
 283        discovery = (discovery_t *) hashbin_get_first(log);
 284        while (discovery != NULL) {
 285                /* Mask out the ones we don't want :
 286                 * We want to match the discovery mask, and to get only
 287                 * the most recent one (unless we want old ones) */
 288                if ((get_unaligned((__u16 *)discovery->data.hints) & mask) &&
 289                    ((old_entries) ||
 290                     ((jiffies - discovery->firststamp) < j_timeout))) {
 291                        /* Create buffer as needed.
 292                         * As this function get called a lot and most time
 293                         * we don't have anything to put in the log (we are
 294                         * quite picky), we can save a lot of overhead
 295                         * by not calling kmalloc. Jean II */
 296                        if(buffer == NULL) {
 297                                /* Create the client specific buffer */
 298                                n = HASHBIN_GET_SIZE(log);
 299                                buffer = kmalloc(n * sizeof(struct irda_device_info), GFP_ATOMIC);
 300                                if (buffer == NULL) {
 301                                        spin_unlock_irqrestore(&log->hb_spinlock, flags);
 302                                        return NULL;
 303                                }
 304
 305                        }
 306
 307                        /* Copy discovery information */
 308                        memcpy(&(buffer[i]), &(discovery->data),
 309                               sizeof(discinfo_t));
 310                        i++;
 311                }
 312                discovery = (discovery_t *) hashbin_get_next(log);
 313        }
 314
 315        spin_unlock_irqrestore(&log->hb_spinlock, flags);
 316
 317        /* Get the actual number of device in the buffer and return */
 318        *pn = i;
 319        return buffer;
 320}
 321
 322#ifdef CONFIG_PROC_FS
 323static inline discovery_t *discovery_seq_idx(loff_t pos)
 324
 325{
 326        discovery_t *discovery;
 327
 328        for (discovery = (discovery_t *) hashbin_get_first(irlmp->cachelog);
 329             discovery != NULL;
 330             discovery = (discovery_t *) hashbin_get_next(irlmp->cachelog)) {
 331                if (pos-- == 0)
 332                        break;
 333        }
 334
 335        return discovery;
 336}
 337
 338static void *discovery_seq_start(struct seq_file *seq, loff_t *pos)
 339{
 340        spin_lock_irq(&irlmp->cachelog->hb_spinlock);
 341        return *pos ? discovery_seq_idx(*pos - 1) : SEQ_START_TOKEN;
 342}
 343
 344static void *discovery_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 345{
 346        ++*pos;
 347        return (v == SEQ_START_TOKEN)
 348                ? (void *) hashbin_get_first(irlmp->cachelog)
 349                : (void *) hashbin_get_next(irlmp->cachelog);
 350}
 351
 352static void discovery_seq_stop(struct seq_file *seq, void *v)
 353{
 354        spin_unlock_irq(&irlmp->cachelog->hb_spinlock);
 355}
 356
 357static int discovery_seq_show(struct seq_file *seq, void *v)
 358{
 359        if (v == SEQ_START_TOKEN)
 360                seq_puts(seq, "IrLMP: Discovery log:\n\n");
 361        else {
 362                const discovery_t *discovery = v;
 363
 364                seq_printf(seq, "nickname: %s, hint: 0x%02x%02x",
 365                           discovery->data.info,
 366                           discovery->data.hints[0],
 367                           discovery->data.hints[1]);
 368#if 0
 369                if ( discovery->data.hints[0] & HINT_PNP)
 370                        seq_puts(seq, "PnP Compatible ");
 371                if ( discovery->data.hints[0] & HINT_PDA)
 372                        seq_puts(seq, "PDA/Palmtop ");
 373                if ( discovery->data.hints[0] & HINT_COMPUTER)
 374                        seq_puts(seq, "Computer ");
 375                if ( discovery->data.hints[0] & HINT_PRINTER)
 376                        seq_puts(seq, "Printer ");
 377                if ( discovery->data.hints[0] & HINT_MODEM)
 378                        seq_puts(seq, "Modem ");
 379                if ( discovery->data.hints[0] & HINT_FAX)
 380                        seq_puts(seq, "Fax ");
 381                if ( discovery->data.hints[0] & HINT_LAN)
 382                        seq_puts(seq, "LAN Access ");
 383
 384                if ( discovery->data.hints[1] & HINT_TELEPHONY)
 385                        seq_puts(seq, "Telephony ");
 386                if ( discovery->data.hints[1] & HINT_FILE_SERVER)
 387                        seq_puts(seq, "File Server ");
 388                if ( discovery->data.hints[1] & HINT_COMM)
 389                        seq_puts(seq, "IrCOMM ");
 390                if ( discovery->data.hints[1] & HINT_OBEX)
 391                        seq_puts(seq, "IrOBEX ");
 392#endif
 393                seq_printf(seq,", saddr: 0x%08x, daddr: 0x%08x\n\n",
 394                               discovery->data.saddr,
 395                               discovery->data.daddr);
 396
 397                seq_putc(seq, '\n');
 398        }
 399        return 0;
 400}
 401
 402static const struct seq_operations discovery_seq_ops = {
 403        .start  = discovery_seq_start,
 404        .next   = discovery_seq_next,
 405        .stop   = discovery_seq_stop,
 406        .show   = discovery_seq_show,
 407};
 408
 409static int discovery_seq_open(struct inode *inode, struct file *file)
 410{
 411        IRDA_ASSERT(irlmp != NULL, return -EINVAL;);
 412
 413        return seq_open(file, &discovery_seq_ops);
 414}
 415
 416const struct file_operations discovery_seq_fops = {
 417        .owner          = THIS_MODULE,
 418        .open           = discovery_seq_open,
 419        .read           = seq_read,
 420        .llseek         = seq_lseek,
 421        .release        = seq_release,
 422};
 423#endif
 424
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