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