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} 220 221 222/* 223 * Function irlmp_copy_discoveries (log, pn, mask) 224 * 225 * Copy all discoveries in a buffer 226 * 227 * This function implement a safe way for lmp clients to access the 228 * discovery log. The basic problem is that we don't want the log 229 * to change (add/remove) while the client is reading it. If the 230 * lmp client manipulate directly the hashbin, he is sure to get 231 * into troubles... 232 * The idea is that we copy all the current discovery log in a buffer 233 * which is specific to the client and pass this copy to him. As we 234 * do this operation with the spinlock grabbed, we are safe... 235 * Note : we don't want those clients to grab the spinlock, because 236 * we have no control on how long they will hold it... 237 * Note : we choose to copy the log in "struct irda_device_info" to 238 * save space... 239 * Note : the client must kfree himself() the log... 240 * Jean II 241 */ 242struct irda_device_info *irlmp_copy_discoveries(hashbin_t *log, int *pn, 243 __u16 mask, int old_entries) 244{ 245 discovery_t * discovery; 246 unsigned long flags; 247 discinfo_t * buffer = NULL; 248 int j_timeout = (sysctl_discovery_timeout * HZ); 249 int n; /* Size of the full log */ 250 int i = 0; /* How many we picked */ 251 252 IRDA_ASSERT(pn != NULL, return NULL;); 253 IRDA_ASSERT(log != NULL, return NULL;); 254 255 /* Save spin lock */ 256 spin_lock_irqsave(&log->hb_spinlock, flags); 257 258 discovery = (discovery_t *) hashbin_get_first(log); 259 while (discovery != NULL) { 260 /* Mask out the ones we don't want : 261 * We want to match the discovery mask, and to get only 262 * the most recent one (unless we want old ones) */ 263 if ((get_unaligned((__u16 *)discovery->data.hints) & mask) && 264 ((old_entries) || 265 ((jiffies - discovery->firststamp) < j_timeout))) { 266 /* Create buffer as needed. 267 * As this function get called a lot and most time 268 * we don't have anything to put in the log (we are 269 * quite picky), we can save a lot of overhead 270 * by not calling kmalloc. Jean II */ 271 if(buffer == NULL) { 272 /* Create the client specific buffer */ 273 n = HASHBIN_GET_SIZE(log); 274 buffer = kmalloc(n * sizeof(struct irda_device_info), GFP_ATOMIC); 275 if (buffer == NULL) { 276 spin_unlock_irqrestore(&log->hb_spinlock, flags); 277 return NULL; 278 } 279 280 } 281 282 /* Copy discovery information */ 283 memcpy(&(buffer[i]), &(discovery->data), 284 sizeof(discinfo_t)); 285 i++; 286 } 287 discovery = (discovery_t *) hashbin_get_next(log); 288 } 289 290 spin_unlock_irqrestore(&log->hb_spinlock, flags); 291 292 /* Get the actual number of device in the buffer and return */ 293 *pn = i; 294 return(buffer); 295} 296 297#ifdef CONFIG_PROC_FS 298static inline discovery_t *discovery_seq_idx(loff_t pos) 299 300{ 301 discovery_t *discovery; 302 303 for (discovery = (discovery_t *) hashbin_get_first(irlmp->cachelog); 304 discovery != NULL; 305 discovery = (discovery_t *) hashbin_get_next(irlmp->cachelog)) { 306 if (pos-- == 0) 307 break; 308 } 309 310 return discovery; 311} 312 313static void *discovery_seq_start(struct seq_file *seq, loff_t *pos) 314{ 315 spin_lock_irq(&irlmp->cachelog->hb_spinlock); 316 return *pos ? discovery_seq_idx(*pos - 1) : SEQ_START_TOKEN; 317} 318 319static void *discovery_seq_next(struct seq_file *seq, void *v, loff_t *pos) 320{ 321 ++*pos; 322 return (v == SEQ_START_TOKEN) 323 ? (void *) hashbin_get_first(irlmp->cachelog) 324 : (void *) hashbin_get_next(irlmp->cachelog); 325} 326 327static void discovery_seq_stop(struct seq_file *seq, void *v) 328{ 329 spin_unlock_irq(&irlmp->cachelog->hb_spinlock); 330} 331 332static int discovery_seq_show(struct seq_file *seq, void *v) 333{ 334 if (v == SEQ_START_TOKEN) 335 seq_puts(seq, "IrLMP: Discovery log:\n\n"); 336 else { 337 const discovery_t *discovery = v; 338 339 seq_printf(seq, "nickname: %s, hint: 0x%02x%02x", 340 discovery->data.info, 341 discovery->data.hints[0], 342 discovery->data.hints[1]); 343 seq_printf(seq,", saddr: 0x%08x, daddr: 0x%08x\n\n", 344 discovery->data.saddr, 345 discovery->data.daddr); 346 347 seq_putc(seq, '\n'); 348 } 349 return 0; 350} 351 352static const struct seq_operations discovery_seq_ops = { 353 .start = discovery_seq_start, 354 .next = discovery_seq_next, 355 .stop = discovery_seq_stop, 356 .show = discovery_seq_show, 357}; 358 359static int discovery_seq_open(struct inode *inode, struct file *file) 360{ 361 IRDA_ASSERT(irlmp != NULL, return -EINVAL;); 362 363 return seq_open(file, &discovery_seq_ops); 364} 365 366const struct file_operations discovery_seq_fops = { 367 .owner = THIS_MODULE, 368 .open = discovery_seq_open, 369 .read = seq_read, 370 .llseek = seq_lseek, 371 .release = seq_release, 372}; 373#endif 374