net/irda/irlmp_frame.c

   1 /*********************************************************************
   2  *
   3  * Filename:      irlmp_frame.c
   4  * Version:       0.9
   5  * Description:   IrLMP frame implementation
   6  * Status:        Experimental.
   7  * Author:        Dag Brattli <dagb@cs.uit.no>
   8  * Created at:    Tue Aug 19 02:09:59 1997
   9  * Modified at:   Mon Dec 13 13:41:12 1999
  10  * Modified by:   Dag Brattli <dagb@cs.uit.no>
  11  *
  12  *     Copyright (c) 1998-1999 Dag Brattli <dagb@cs.uit.no>
  13  *     All Rights Reserved.
  14  *     Copyright (c) 2000-2003 Jean Tourrilhes <jt@hpl.hp.com>
  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  *     Neither Dag Brattli nor University of Tromsø admit liability nor
  22  *     provide warranty for any of this software. This material is
  23  *     provided "AS-IS" and at no charge.
  24  *
  25  ********************************************************************/
  26
  27 #include <linux/config.h>
  28 #include <linux/skbuff.h>
  29 #include <linux/kernel.h>
  30
  31 #include <net/irda/irda.h>
  32 #include <net/irda/irlap.h>
  33 #include <net/irda/timer.h>
  34 #include <net/irda/irlmp.h>
  35 #include <net/irda/irlmp_frame.h>
  36 #include <net/irda/discovery.h>
  37
  38 static struct lsap_cb *irlmp_find_lsap(struct lap_cb *self, __u8 dlsap,
  39                                        __u8 slsap, int status, hashbin_t *);
  40
  41 inline void irlmp_send_data_pdu(struct lap_cb *self, __u8 dlsap, __u8 slsap,
  42                                 int expedited, struct sk_buff *skb)
  43 {
  44         skb->data[0] = dlsap;
  45         skb->data[1] = slsap;
  46
  47         if (expedited) {
  48                 IRDA_DEBUG(4, "%s(), sending expedited data\n", __FUNCTION__);
  49                 irlap_data_request(self->irlap, skb, TRUE);
  50         } else
  51                 irlap_data_request(self->irlap, skb, FALSE);
  52 }
  53
  54 /*
  55  * Function irlmp_send_lcf_pdu (dlsap, slsap, opcode,skb)
  56  *
  57  *    Send Link Control Frame to IrLAP
  58  */
  59 void irlmp_send_lcf_pdu(struct lap_cb *self, __u8 dlsap, __u8 slsap,
  60                         __u8 opcode, struct sk_buff *skb)
  61 {
  62         __u8 *frame;
  63
  64         IRDA_DEBUG(2, "%s()\n", __FUNCTION__);
  65
  66         IRDA_ASSERT(self != NULL, return;);
  67         IRDA_ASSERT(self->magic == LMP_LAP_MAGIC, return;);
  68         IRDA_ASSERT(skb != NULL, return;);
  69
  70         frame = skb->data;
  71
  72         frame[0] = dlsap | CONTROL_BIT;
  73         frame[1] = slsap;
  74
  75         frame[2] = opcode;
  76
  77         if (opcode == DISCONNECT)
  78                 frame[3] = 0x01; /* Service user request */
  79         else
  80                 frame[3] = 0x00; /* rsvd */
  81
  82         irlap_data_request(self->irlap, skb, FALSE);
  83 }
  84
  85 /*
  86  * Function irlmp_input (skb)
  87  *
  88  *    Used by IrLAP to pass received data frames to IrLMP layer
  89  *
  90  */
  91 void irlmp_link_data_indication(struct lap_cb *self, struct sk_buff *skb,
  92                                 int unreliable)
  93 {
  94         struct lsap_cb *lsap;
  95         __u8   slsap_sel;   /* Source (this) LSAP address */
  96         __u8   dlsap_sel;   /* Destination LSAP address */
  97         __u8   *fp;
  98
  99         IRDA_DEBUG(4, "%s()\n", __FUNCTION__);
 100
 101         IRDA_ASSERT(self != NULL, return;);
 102         IRDA_ASSERT(self->magic == LMP_LAP_MAGIC, return;);
 103         IRDA_ASSERT(skb->len > 2, return;);
 104
 105         fp = skb->data;
 106
 107         /*
 108          *  The next statements may be confusing, but we do this so that
 109          *  destination LSAP of received frame is source LSAP in our view
 110          */
 111         slsap_sel = fp[0] & LSAP_MASK;
 112         dlsap_sel = fp[1];
 113
 114         /*
 115          *  Check if this is an incoming connection, since we must deal with
 116          *  it in a different way than other established connections.
 117          */
 118         if ((fp[0] & CONTROL_BIT) && (fp[2] == CONNECT_CMD)) {
 119                 IRDA_DEBUG(3, "%s(), incoming connection, "
 120                            "source LSAP=%d, dest LSAP=%d\n",
 121                            __FUNCTION__, slsap_sel, dlsap_sel);
 122
 123                 /* Try to find LSAP among the unconnected LSAPs */
 124                 lsap = irlmp_find_lsap(self, dlsap_sel, slsap_sel, CONNECT_CMD,
 125                                        irlmp->unconnected_lsaps);
 126
 127                 /* Maybe LSAP was already connected, so try one more time */
 128                 if (!lsap) {
 129                         IRDA_DEBUG(1, "%s(), incoming connection for LSAP already connected\n", __FUNCTION__);
 130                         lsap = irlmp_find_lsap(self, dlsap_sel, slsap_sel, 0,
 131                                                self->lsaps);
 132                 }
 133         } else
 134                 lsap = irlmp_find_lsap(self, dlsap_sel, slsap_sel, 0,
 135                                        self->lsaps);
 136
 137         if (lsap == NULL) {
 138                 IRDA_DEBUG(2, "IrLMP, Sorry, no LSAP for received frame!\n");
 139                 IRDA_DEBUG(2, "%s(), slsap_sel = %02x, dlsap_sel = %02x\n",
 140                            __FUNCTION__, slsap_sel, dlsap_sel);
 141                 if (fp[0] & CONTROL_BIT) {
 142                         IRDA_DEBUG(2, "%s(), received control frame %02x\n",
 143                                    __FUNCTION__, fp[2]);
 144                 } else {
 145                         IRDA_DEBUG(2, "%s(), received data frame\n", __FUNCTION__);
 146                 }
 147                 return;
 148         }
 149
 150         /*
 151          *  Check if we received a control frame?
 152          */
 153         if (fp[0] & CONTROL_BIT) {
 154                 switch (fp[2]) {
 155                 case CONNECT_CMD:
 156                         lsap->lap = self;
 157                         irlmp_do_lsap_event(lsap, LM_CONNECT_INDICATION, skb);
 158                         break;
 159                 case CONNECT_CNF:
 160                         irlmp_do_lsap_event(lsap, LM_CONNECT_CONFIRM, skb);
 161                         break;
 162                 case DISCONNECT:
 163                         IRDA_DEBUG(4, "%s(), Disconnect indication!\n",
 164                                    __FUNCTION__);
 165                         irlmp_do_lsap_event(lsap, LM_DISCONNECT_INDICATION,
 166                                             skb);
 167                         break;
 168                 case ACCESSMODE_CMD:
 169                         IRDA_DEBUG(0, "Access mode cmd not implemented!\n");
 170                         break;
 171                 case ACCESSMODE_CNF:
 172                         IRDA_DEBUG(0, "Access mode cnf not implemented!\n");
 173                         break;
 174                 default:
 175                         IRDA_DEBUG(0, "%s(), Unknown control frame %02x\n",
 176                                    __FUNCTION__, fp[2]);
 177                         break;
 178                 }
 179         } else if (unreliable) {
 180                 /* Optimize and bypass the state machine if possible */
 181                 if (lsap->lsap_state == LSAP_DATA_TRANSFER_READY)
 182                         irlmp_udata_indication(lsap, skb);
 183                 else
 184                         irlmp_do_lsap_event(lsap, LM_UDATA_INDICATION, skb);
 185         } else {
 186                 /* Optimize and bypass the state machine if possible */
 187                 if (lsap->lsap_state == LSAP_DATA_TRANSFER_READY)
 188                         irlmp_data_indication(lsap, skb);
 189                 else
 190                         irlmp_do_lsap_event(lsap, LM_DATA_INDICATION, skb);
 191         }
 192 }
 193
 194 /*
 195  * Function irlmp_link_unitdata_indication (self, skb)
 196  *
 197  *
 198  *
 199  */
 200 #ifdef CONFIG_IRDA_ULTRA
 201 void irlmp_link_unitdata_indication(struct lap_cb *self, struct sk_buff *skb)
 202 {
 203         struct lsap_cb *lsap;
 204         __u8   slsap_sel;   /* Source (this) LSAP address */
 205         __u8   dlsap_sel;   /* Destination LSAP address */
 206         __u8   pid;         /* Protocol identifier */
 207         __u8   *fp;
 208         unsigned long flags;
 209
 210         IRDA_DEBUG(4, "%s()\n", __FUNCTION__);
 211
 212         IRDA_ASSERT(self != NULL, return;);
 213         IRDA_ASSERT(self->magic == LMP_LAP_MAGIC, return;);
 214         IRDA_ASSERT(skb->len > 2, return;);
 215
 216         fp = skb->data;
 217
 218         /*
 219          *  The next statements may be confusing, but we do this so that
 220          *  destination LSAP of received frame is source LSAP in our view
 221          */
 222         slsap_sel = fp[0] & LSAP_MASK;
 223         dlsap_sel = fp[1];
 224         pid       = fp[2];
 225
 226         if (pid & 0x80) {
 227                 IRDA_DEBUG(0, "%s(), extension in PID not supp!\n",
 228                            __FUNCTION__);
 229                 return;
 230         }
 231
 232         /* Check if frame is addressed to the connectionless LSAP */
 233         if ((slsap_sel != LSAP_CONNLESS) || (dlsap_sel != LSAP_CONNLESS)) {
 234                 IRDA_DEBUG(0, "%s(), dropping frame!\n", __FUNCTION__);
 235                 return;
 236         }
 237
 238         /* Search the connectionless LSAP */
 239         spin_lock_irqsave(&irlmp->unconnected_lsaps->hb_spinlock, flags);
 240         lsap = (struct lsap_cb *) hashbin_get_first(irlmp->unconnected_lsaps);
 241         while (lsap != NULL) {
 242                 /*
 243                  *  Check if source LSAP and dest LSAP selectors and PID match.
 244                  */
 245                 if ((lsap->slsap_sel == slsap_sel) &&
 246                     (lsap->dlsap_sel == dlsap_sel) &&
 247                     (lsap->pid == pid))
 248                 {
 249                         break;
 250                 }
 251                 lsap = (struct lsap_cb *) hashbin_get_next(irlmp->unconnected_lsaps);
 252         }
 253         spin_unlock_irqrestore(&irlmp->unconnected_lsaps->hb_spinlock, flags);
 254
 255         if (lsap)
 256                 irlmp_connless_data_indication(lsap, skb);
 257         else {
 258                 IRDA_DEBUG(0, "%s(), found no matching LSAP!\n", __FUNCTION__);
 259         }
 260 }
 261 #endif /* CONFIG_IRDA_ULTRA */
 262
 263 /*
 264  * Function irlmp_link_disconnect_indication (reason, userdata)
 265  *
 266  *    IrLAP has disconnected
 267  *
 268  */
 269 void irlmp_link_disconnect_indication(struct lap_cb *lap,
 270                                       struct irlap_cb *irlap,
 271                                       LAP_REASON reason,
 272                                       struct sk_buff *skb)
 273 {
 274         IRDA_DEBUG(2, "%s()\n", __FUNCTION__);
 275
 276         IRDA_ASSERT(lap != NULL, return;);
 277         IRDA_ASSERT(lap->magic == LMP_LAP_MAGIC, return;);
 278
 279         lap->reason = reason;
 280         lap->daddr = DEV_ADDR_ANY;
 281
 282         /* FIXME: must do something with the skb if any */
 283
 284         /*
 285          *  Inform station state machine
 286          */
 287         irlmp_do_lap_event(lap, LM_LAP_DISCONNECT_INDICATION, NULL);
 288 }
 289
 290 /*
 291  * Function irlmp_link_connect_indication (qos)
 292  *
 293  *    Incoming LAP connection!
 294  *
 295  */
 296 void irlmp_link_connect_indication(struct lap_cb *self, __u32 saddr,
 297                                    __u32 daddr, struct qos_info *qos,
 298                                    struct sk_buff *skb)
 299 {
 300         IRDA_DEBUG(4, "%s()\n", __FUNCTION__);
 301
 302         /* Copy QoS settings for this session */
 303         self->qos = qos;
 304
 305         /* Update destination device address */
 306         self->daddr = daddr;
 307         IRDA_ASSERT(self->saddr == saddr, return;);
 308
 309         irlmp_do_lap_event(self, LM_LAP_CONNECT_INDICATION, skb);
 310 }
 311
 312 /*
 313  * Function irlmp_link_connect_confirm (qos)
 314  *
 315  *    LAP connection confirmed!
 316  *
 317  */
 318 void irlmp_link_connect_confirm(struct lap_cb *self, struct qos_info *qos,
 319                                 struct sk_buff *skb)
 320 {
 321         IRDA_DEBUG(4, "%s()\n", __FUNCTION__);
 322
 323         IRDA_ASSERT(self != NULL, return;);
 324         IRDA_ASSERT(self->magic == LMP_LAP_MAGIC, return;);
 325         IRDA_ASSERT(qos != NULL, return;);
 326
 327         /* Don't need use the skb for now */
 328
 329         /* Copy QoS settings for this session */
 330         self->qos = qos;
 331
 332         irlmp_do_lap_event(self, LM_LAP_CONNECT_CONFIRM, NULL);
 333 }
 334
 335 /*
 336  * Function irlmp_link_discovery_indication (self, log)
 337  *
 338  *    Device is discovering us
 339  *
 340  * It's not an answer to our own discoveries, just another device trying
 341  * to perform discovery, but we don't want to miss the opportunity
 342  * to exploit this information, because :
 343  *      o We may not actively perform discovery (just passive discovery)
 344  *      o This type of discovery is much more reliable. In some cases, it
 345  *        seem that less than 50% of our discoveries get an answer, while
 346  *        we always get ~100% of these.
 347  *      o Make faster discovery, statistically divide time of discovery
 348  *        events by 2 (important for the latency aspect and user feel)
 349  *      o Even is we do active discovery, the other node might not
 350  *        answer our discoveries (ex: Palm). The Palm will just perform
 351  *        one active discovery and connect directly to us.
 352  *
 353  * However, when both devices discover each other, they might attempt to
 354  * connect to each other following the discovery event, and it would create
 355  * collisions on the medium (SNRM battle).
 356  * The "fix" for that is to disable all connection requests in IrLAP
 357  * for 100ms after a discovery indication by setting the media_busy flag.
 358  * Previously, we used to postpone the event which was quite ugly. Now
 359  * that IrLAP takes care of this problem, just pass the event up...
 360  *
 361  * Jean II
 362  */
 363 void irlmp_link_discovery_indication(struct lap_cb *self,
 364                                      discovery_t *discovery)
 365 {
 366         IRDA_ASSERT(self != NULL, return;);
 367         IRDA_ASSERT(self->magic == LMP_LAP_MAGIC, return;);
 368
 369         /* Add to main log, cleanup */
 370         irlmp_add_discovery(irlmp->cachelog, discovery);
 371
 372         /* Just handle it the same way as a discovery confirm,
 373          * bypass the LM_LAP state machine (see below) */
 374         irlmp_discovery_confirm(irlmp->cachelog, DISCOVERY_PASSIVE);
 375 }
 376
 377 /*
 378  * Function irlmp_link_discovery_confirm (self, log)
 379  *
 380  *    Called by IrLAP with a list of discoveries after the discovery
 381  *    request has been carried out. A NULL log is received if IrLAP
 382  *    was unable to carry out the discovery request
 383  *
 384  */
 385 void irlmp_link_discovery_confirm(struct lap_cb *self, hashbin_t *log)
 386 {
 387         IRDA_DEBUG(4, "%s()\n", __FUNCTION__);
 388
 389         IRDA_ASSERT(self != NULL, return;);
 390         IRDA_ASSERT(self->magic == LMP_LAP_MAGIC, return;);
 391
 392         /* Add to main log, cleanup */
 393         irlmp_add_discovery_log(irlmp->cachelog, log);
 394
 395         /* Propagate event to various LSAPs registered for it.
 396          * We bypass the LM_LAP state machine because
 397          *      1) We do it regardless of the LM_LAP state
 398          *      2) It doesn't affect the LM_LAP state
 399          *      3) Faster, slimer, simpler, ...
 400          * Jean II */
 401         irlmp_discovery_confirm(irlmp->cachelog, DISCOVERY_ACTIVE);
 402 }
 403
 404 #ifdef CONFIG_IRDA_CACHE_LAST_LSAP
 405 static inline void irlmp_update_cache(struct lap_cb *lap,
 406                                       struct lsap_cb *lsap)
 407 {
 408         /* Prevent concurrent read to get garbage */
 409         lap->cache.valid = FALSE;
 410         /* Update cache entry */
 411         lap->cache.dlsap_sel = lsap->dlsap_sel;
 412         lap->cache.slsap_sel = lsap->slsap_sel;
 413         lap->cache.lsap = lsap;
 414         lap->cache.valid = TRUE;
 415 }
 416 #endif
 417
 418 /*
 419  * Function irlmp_find_handle (self, dlsap_sel, slsap_sel, status, queue)
 420  *
 421  *    Find handle associated with destination and source LSAP
 422  *
 423  * Any IrDA connection (LSAP/TSAP) is uniquely identified by
 424  * 3 parameters, the local lsap, the remote lsap and the remote address.
 425  * We may initiate multiple connections to the same remote service
 426  * (they will have different local lsap), a remote device may initiate
 427  * multiple connections to the same local service (they will have
 428  * different remote lsap), or multiple devices may connect to the same
 429  * service and may use the same remote lsap (and they will have
 430  * different remote address).
 431  * So, where is the remote address ? Each LAP connection is made with
 432  * a single remote device, so imply a specific remote address.
 433  * Jean II
 434  */
 435 static struct lsap_cb *irlmp_find_lsap(struct lap_cb *self, __u8 dlsap_sel,
 436                                        __u8 slsap_sel, int status,
 437                                        hashbin_t *queue)
 438 {
 439         struct lsap_cb *lsap;
 440         unsigned long flags;
 441
 442         /*
 443          *  Optimize for the common case. We assume that the last frame
 444          *  received is in the same connection as the last one, so check in
 445          *  cache first to avoid the linear search
 446          */
 447 #ifdef CONFIG_IRDA_CACHE_LAST_LSAP
 448         if ((self->cache.valid) &&
 449             (self->cache.slsap_sel == slsap_sel) &&
 450             (self->cache.dlsap_sel == dlsap_sel))
 451         {
 452                 return (self->cache.lsap);
 453         }
 454 #endif
 455
 456         spin_lock_irqsave(&queue->hb_spinlock, flags);
 457
 458         lsap = (struct lsap_cb *) hashbin_get_first(queue);
 459         while (lsap != NULL) {
 460                 /*
 461                  *  If this is an incoming connection, then the destination
 462                  *  LSAP selector may have been specified as LM_ANY so that
 463                  *  any client can connect. In that case we only need to check
 464                  *  if the source LSAP (in our view!) match!
 465                  */
 466                 if ((status == CONNECT_CMD) &&
 467                     (lsap->slsap_sel == slsap_sel) &&
 468                     (lsap->dlsap_sel == LSAP_ANY)) {
 469                         /* This is where the dest lsap sel is set on incoming
 470                          * lsaps */
 471                         lsap->dlsap_sel = dlsap_sel;
 472                         break;
 473                 }
 474                 /*
 475                  *  Check if source LSAP and dest LSAP selectors match.
 476                  */
 477                 if ((lsap->slsap_sel == slsap_sel) &&
 478                     (lsap->dlsap_sel == dlsap_sel))
 479                         break;
 480
 481                 lsap = (struct lsap_cb *) hashbin_get_next(queue);
 482         }
 483 #ifdef CONFIG_IRDA_CACHE_LAST_LSAP
 484         if(lsap)
 485                 irlmp_update_cache(self, lsap);
 486 #endif
 487         spin_unlock_irqrestore(&queue->hb_spinlock, flags);
 488
 489         /* Return what we've found or NULL */
 490         return lsap;
 491 }