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