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

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