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) 2000-2001 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, __FUNCTION__ "(), sending expedited data\n");
  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, __FUNCTION__ "()\n");
  65
  66         ASSERT(self != NULL, return;);
  67         ASSERT(self->magic == LMP_LAP_MAGIC, return;);
  68         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, __FUNCTION__ "()\n");
 100
 101         ASSERT(self != NULL, return;);
 102         ASSERT(self->magic == LMP_LAP_MAGIC, return;);
 103         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, __FUNCTION__ "(), incoming connection, "
 120                            "source LSAP=%d, dest LSAP=%d\n",
 121                            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, __FUNCTION__ "(), incoming connection for LSAP already connected\n");
 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, __FUNCTION__
 140                       "(), slsap_sel = %02x, dlsap_sel = %02x\n", slsap_sel,
 141                       dlsap_sel);
 142                 if (fp[0] & CONTROL_BIT) {
 143                         IRDA_DEBUG(2, __FUNCTION__
 144                               "(), received control frame %02x\n", fp[2]);
 145                 } else {
 146                         IRDA_DEBUG(2, __FUNCTION__ "(), received data frame\n");
 147                 }
 148                 dev_kfree_skb(skb);
 149                 return;
 150         }
 151
 152         /*
 153          *  Check if we received a control frame?
 154          */
 155         if (fp[0] & CONTROL_BIT) {
 156                 switch (fp[2]) {
 157                 case CONNECT_CMD:
 158                         lsap->lap = self;
 159                         irlmp_do_lsap_event(lsap, LM_CONNECT_INDICATION, skb);
 160                         break;
 161                 case CONNECT_CNF:
 162                         irlmp_do_lsap_event(lsap, LM_CONNECT_CONFIRM, skb);
 163                         break;
 164                 case DISCONNECT:
 165                         IRDA_DEBUG(4, __FUNCTION__
 166                                    "(), Disconnect indication!\n");
 167                         irlmp_do_lsap_event(lsap, LM_DISCONNECT_INDICATION,
 168                                             skb);
 169                         break;
 170                 case ACCESSMODE_CMD:
 171                         IRDA_DEBUG(0, "Access mode cmd not implemented!\n");
 172                         dev_kfree_skb(skb);
 173                         break;
 174                 case ACCESSMODE_CNF:
 175                         IRDA_DEBUG(0, "Access mode cnf not implemented!\n");
 176                         dev_kfree_skb(skb);
 177                         break;
 178                 default:
 179                         IRDA_DEBUG(0, __FUNCTION__
 180                                    "(), Unknown control frame %02x\n", fp[2]);
 181                         dev_kfree_skb(skb);
 182                         break;
 183                 }
 184         } else if (unreliable) {
 185                 /* Optimize and bypass the state machine if possible */
 186                 if (lsap->lsap_state == LSAP_DATA_TRANSFER_READY)
 187                         irlmp_udata_indication(lsap, skb);
 188                 else
 189                         irlmp_do_lsap_event(lsap, LM_UDATA_INDICATION, skb);
 190         } else {
 191                 /* Optimize and bypass the state machine if possible */
 192                 if (lsap->lsap_state == LSAP_DATA_TRANSFER_READY)
 193                         irlmp_data_indication(lsap, skb);
 194                 else
 195                         irlmp_do_lsap_event(lsap, LM_DATA_INDICATION, skb);
 196         }
 197 }
 198
 199 /*
 200  * Function irlmp_link_unitdata_indication (self, skb)
 201  *
 202  *
 203  *
 204  */
 205 #ifdef CONFIG_IRDA_ULTRA
 206 void irlmp_link_unitdata_indication(struct lap_cb *self, struct sk_buff *skb)
 207 {
 208         struct lsap_cb *lsap;
 209         __u8   slsap_sel;   /* Source (this) LSAP address */
 210         __u8   dlsap_sel;   /* Destination LSAP address */
 211         __u8   pid;         /* Protocol identifier */
 212         __u8   *fp;
 213
 214         IRDA_DEBUG(4, __FUNCTION__ "()\n");
 215
 216         ASSERT(self != NULL, return;);
 217         ASSERT(self->magic == LMP_LAP_MAGIC, return;);
 218         ASSERT(skb->len > 2, return;);
 219
 220         fp = skb->data;
 221
 222         /*
 223          *  The next statements may be confusing, but we do this so that
 224          *  destination LSAP of received frame is source LSAP in our view
 225          */
 226         slsap_sel = fp[0] & LSAP_MASK;
 227         dlsap_sel = fp[1];
 228         pid       = fp[2];
 229
 230         if (pid & 0x80) {
 231                 IRDA_DEBUG(0, __FUNCTION__ "(), extension in PID not supp!\n");
 232                 dev_kfree_skb(skb);
 233
 234                 return;
 235         }
 236
 237         /* Check if frame is addressed to the connectionless LSAP */
 238         if ((slsap_sel != LSAP_CONNLESS) || (dlsap_sel != LSAP_CONNLESS)) {
 239                 IRDA_DEBUG(0, __FUNCTION__ "(), dropping frame!\n");
 240                 dev_kfree_skb(skb);
 241
 242                 return;
 243         }
 244
 245         lsap = (struct lsap_cb *) hashbin_get_first(irlmp->unconnected_lsaps);
 246         while (lsap != NULL) {
 247                 /*
 248                  *  Check if source LSAP and dest LSAP selectors and PID match.
 249                  */
 250                 if ((lsap->slsap_sel == slsap_sel) &&
 251                     (lsap->dlsap_sel == dlsap_sel) &&
 252                     (lsap->pid == pid))
 253                 {
 254                         break;
 255                 }
 256                 lsap = (struct lsap_cb *) hashbin_get_next(irlmp->unconnected_lsaps);
 257         }
 258         if (lsap)
 259                 irlmp_connless_data_indication(lsap, skb);
 260         else {
 261                 IRDA_DEBUG(0, __FUNCTION__ "(), found no matching LSAP!\n");
 262                 dev_kfree_skb(skb);
 263         }
 264 }
 265 #endif /* CONFIG_IRDA_ULTRA */
 266
 267 /*
 268  * Function irlmp_link_disconnect_indication (reason, userdata)
 269  *
 270  *    IrLAP has disconnected
 271  *
 272  */
 273 void irlmp_link_disconnect_indication(struct lap_cb *lap,
 274                                       struct irlap_cb *irlap,
 275                                       LAP_REASON reason,
 276                                       struct sk_buff *userdata)
 277 {
 278         IRDA_DEBUG(2, __FUNCTION__ "()\n");
 279
 280         ASSERT(lap != NULL, return;);
 281         ASSERT(lap->magic == LMP_LAP_MAGIC, return;);
 282
 283         lap->reason = reason;
 284         lap->daddr = DEV_ADDR_ANY;
 285
 286         /* FIXME: must do something with the userdata if any */
 287         if (userdata)
 288                 dev_kfree_skb(userdata);
 289
 290         /*
 291          *  Inform station state machine
 292          */
 293         irlmp_do_lap_event(lap, LM_LAP_DISCONNECT_INDICATION, NULL);
 294 }
 295
 296 /*
 297  * Function irlmp_link_connect_indication (qos)
 298  *
 299  *    Incoming LAP connection!
 300  *
 301  */
 302 void irlmp_link_connect_indication(struct lap_cb *self, __u32 saddr,
 303                                    __u32 daddr, struct qos_info *qos,
 304                                    struct sk_buff *skb)
 305 {
 306         IRDA_DEBUG(4, __FUNCTION__ "()\n");
 307
 308         /* Copy QoS settings for this session */
 309         self->qos = qos;
 310
 311         /* Update destination device address */
 312         self->daddr = daddr;
 313         ASSERT(self->saddr == saddr, return;);
 314
 315         irlmp_do_lap_event(self, LM_LAP_CONNECT_INDICATION, skb);
 316 }
 317
 318 /*
 319  * Function irlmp_link_connect_confirm (qos)
 320  *
 321  *    LAP connection confirmed!
 322  *
 323  */
 324 void irlmp_link_connect_confirm(struct lap_cb *self, struct qos_info *qos,
 325                                 struct sk_buff *userdata)
 326 {
 327         IRDA_DEBUG(4, __FUNCTION__ "()\n");
 328
 329         ASSERT(self != NULL, return;);
 330         ASSERT(self->magic == LMP_LAP_MAGIC, return;);
 331         ASSERT(qos != NULL, return;);
 332
 333         /* Don't need use the userdata for now */
 334         if (userdata)
 335                 dev_kfree_skb(userdata);
 336
 337         /* Copy QoS settings for this session */
 338         self->qos = qos;
 339
 340         irlmp_do_lap_event(self, LM_LAP_CONNECT_CONFIRM, NULL);
 341 }
 342
 343 /*
 344  * Function irlmp_link_discovery_indication (self, log)
 345  *
 346  *    Device is discovering us
 347  *
 348  * It's not an answer to our own discoveries, just another device trying
 349  * to perform discovery, but we don't want to miss the opportunity
 350  * to exploit this information, because :
 351  *      o We may not actively perform discovery (just passive discovery)
 352  *      o This type of discovery is much more reliable. In some cases, it
 353  *        seem that less than 50% of our discoveries get an answer, while
 354  *        we always get ~100% of these.
 355  *      o Make faster discovery, statistically divide time of discovery
 356  *        events by 2 (important for the latency aspect and user feel)
 357  *      o Even is we do active discovery, the other node might not
 358  *        answer our discoveries (ex: Palm). The Palm will just perform
 359  *        one active discovery and connect directly to us.
 360  *
 361  * However, when both devices discover each other, they might attempt to
 362  * connect to each other following the discovery event, and it would create
 363  * collisions on the medium (SNRM battle).
 364  * The "fix" for that is to disable all connection requests in IrLAP
 365  * for 100ms after a discovery indication by setting the media_busy flag.
 366  * Previously, we used to postpone the event which was quite ugly. Now
 367  * that IrLAP takes care of this problem, just pass the event up...
 368  *
 369  * Jean II
 370  */
 371 void irlmp_link_discovery_indication(struct lap_cb *self,
 372                                      discovery_t *discovery)
 373 {
 374         ASSERT(self != NULL, return;);
 375         ASSERT(self->magic == LMP_LAP_MAGIC, return;);
 376
 377         irlmp_add_discovery(irlmp->cachelog, discovery);
 378
 379         /* Just handle it the same way as a discovery confirm,
 380          * bypass the LM_LAP state machine (see below) */
 381         irlmp_discovery_confirm(irlmp->cachelog, DISCOVERY_PASSIVE);
 382 }
 383
 384 /*
 385  * Function irlmp_link_discovery_confirm (self, log)
 386  *
 387  *    Called by IrLAP with a list of discoveries after the discovery
 388  *    request has been carried out. A NULL log is received if IrLAP
 389  *    was unable to carry out the discovery request
 390  *
 391  */
 392 void irlmp_link_discovery_confirm(struct lap_cb *self, hashbin_t *log)
 393 {
 394         IRDA_DEBUG(4, __FUNCTION__ "()\n");
 395
 396         ASSERT(self != NULL, return;);
 397         ASSERT(self->magic == LMP_LAP_MAGIC, return;);
 398
 399         irlmp_add_discovery_log(irlmp->cachelog, log);
 400
 401         /* Propagate event to various LSAPs registered for it.
 402          * We bypass the LM_LAP state machine because
 403          *      1) We do it regardless of the LM_LAP state
 404          *      2) It doesn't affect the LM_LAP state
 405          *      3) Faster, slimer, simpler, ...
 406          * Jean II */
 407         irlmp_discovery_confirm(irlmp->cachelog, DISCOVERY_ACTIVE);
 408 }
 409
 410 #ifdef CONFIG_IRDA_CACHE_LAST_LSAP
 411 inline void irlmp_update_cache(struct lsap_cb *self)
 412 {
 413         /* Update cache entry */
 414         irlmp->cache.dlsap_sel = self->dlsap_sel;
 415         irlmp->cache.slsap_sel = self->slsap_sel;
 416         irlmp->cache.lsap = self;
 417         irlmp->cache.valid = TRUE;
 418 }
 419 #endif
 420
 421 /*
 422  * Function irlmp_find_handle (self, dlsap_sel, slsap_sel, status, queue)
 423  *
 424  *    Find handle assosiated with destination and source LSAP
 425  *
 426  */
 427 static struct lsap_cb *irlmp_find_lsap(struct lap_cb *self, __u8 dlsap_sel,
 428                                        __u8 slsap_sel, int status,
 429                                        hashbin_t *queue)
 430 {
 431         struct lsap_cb *lsap;
 432
 433         /*
 434          *  Optimize for the common case. We assume that the last frame
 435          *  received is in the same connection as the last one, so check in
 436          *  cache first to avoid the linear search
 437          */
 438 #ifdef CONFIG_IRDA_CACHE_LAST_LSAP
 439         if ((irlmp->cache.valid) &&
 440             (irlmp->cache.slsap_sel == slsap_sel) &&
 441             (irlmp->cache.dlsap_sel == dlsap_sel))
 442         {
 443                 return (irlmp->cache.lsap);
 444         }
 445 #endif
 446         lsap = (struct lsap_cb *) hashbin_get_first(queue);
 447         while (lsap != NULL) {
 448                 /*
 449                  *  If this is an incoming connection, then the destination
 450                  *  LSAP selector may have been specified as LM_ANY so that
 451                  *  any client can connect. In that case we only need to check
 452                  *  if the source LSAP (in our view!) match!
 453                  */
 454                 if ((status == CONNECT_CMD) &&
 455                     (lsap->slsap_sel == slsap_sel) &&
 456                     (lsap->dlsap_sel == LSAP_ANY))
 457                 {
 458                         lsap->dlsap_sel = dlsap_sel;
 459
 460 #ifdef CONFIG_IRDA_CACHE_LAST_LSAP
 461                         irlmp_update_cache(lsap);
 462 #endif
 463                         return lsap;
 464                 }
 465                 /*
 466                  *  Check if source LSAP and dest LSAP selectors match.
 467                  */
 468                 if ((lsap->slsap_sel == slsap_sel) &&
 469                     (lsap->dlsap_sel == dlsap_sel))
 470                 {
 471 #ifdef CONFIG_IRDA_CACHE_LAST_LSAP
 472                         irlmp_update_cache(lsap);
 473 #endif
 474                         return lsap;
 475                 }
 476                 lsap = (struct lsap_cb *) hashbin_get_next(queue);
 477         }
 478
 479         /* Sorry not found! */
 480         return NULL;
 481 }