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   1 /*********************************************************************
   2  *
   3  * Filename:      irlap_frame.c
   4  * Version:       1.0
   5  * Description:   Build and transmit IrLAP frames
   6  * Status:        Stable
   7  * Author:        Dag Brattli <dagb@cs.uit.no>
   8  * Created at:    Tue Aug 19 10:27:26 1997
   9  * Modified at:   Wed Jan  5 08:59:04 2000
  10  * Modified by:   Dag Brattli <dagb@cs.uit.no>
  11  *
  12  *     Copyright (c) 1998-2000 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/if.h>
  29 #include <linux/if_ether.h>
  30 #include <linux/netdevice.h>
  31 #include <linux/irda.h>
  32
  33 #include <net/pkt_sched.h>
  34 #include <net/sock.h>
  35
  36 #include <asm/byteorder.h>
  37
  38 #include <net/irda/irda.h>
  39 #include <net/irda/irda_device.h>
  40 #include <net/irda/irlap.h>
  41 #include <net/irda/wrapper.h>
  42 #include <net/irda/timer.h>
  43 #include <net/irda/irlap_frame.h>
  44 #include <net/irda/qos.h>
  45
  46 static void irlap_send_i_frame(struct irlap_cb *self, struct sk_buff *skb,
  47                                int command);
  48
  49 /*
  50  * Function irlap_insert_info (self, skb)
  51  *
  52  *    Insert minimum turnaround time and speed information into the skb. We
  53  *    need to do this since it's per packet relevant information. Safe to
  54  *    have this function inlined since it's only called from one place
  55  */
  56 static inline void irlap_insert_info(struct irlap_cb *self,
  57                                      struct sk_buff *skb)
  58 {
  59         struct irda_skb_cb *cb = (struct irda_skb_cb *) skb->cb;
  60
  61         /*
  62          * Insert MTT (min. turn time) and speed into skb, so that the
  63          * device driver knows which settings to use
  64          */
  65         cb->magic = LAP_MAGIC;
  66         cb->mtt = self->mtt_required;
  67         cb->next_speed = self->speed;
  68
  69         /* Reset */
  70         self->mtt_required = 0;
  71
  72         /*
  73          * Delay equals negotiated BOFs count, plus the number of BOFs to
  74          * force the negotiated minimum turnaround time
  75          */
  76         cb->xbofs = self->bofs_count;
  77         cb->next_xbofs = self->next_bofs;
  78         cb->xbofs_delay = self->xbofs_delay;
  79
  80         /* Reset XBOF's delay (used only for getting min turn time) */
  81         self->xbofs_delay = 0;
  82         /* Put the correct xbofs value for the next packet */
  83         self->bofs_count = self->next_bofs;
  84 }
  85
  86 /*
  87  * Function irlap_queue_xmit (self, skb)
  88  *
  89  *    A little wrapper for dev_queue_xmit, so we can insert some common
  90  *    code into it.
  91  */
  92 void irlap_queue_xmit(struct irlap_cb *self, struct sk_buff *skb)
  93 {
  94         /* Some common init stuff */
  95         skb->dev = self->netdev;
  96         skb->h.raw = skb->nh.raw = skb->mac.raw = skb->data;
  97         skb->protocol = htons(ETH_P_IRDA);
  98         skb->priority = TC_PRIO_BESTEFFORT;
  99
 100         irlap_insert_info(self, skb);
 101
 102         dev_queue_xmit(skb);
 103 }
 104
 105 /*
 106  * Function irlap_send_snrm_cmd (void)
 107  *
 108  *    Transmits a connect SNRM command frame
 109  */
 110 void irlap_send_snrm_frame(struct irlap_cb *self, struct qos_info *qos)
 111 {
 112         struct sk_buff *tx_skb;
 113         struct snrm_frame *frame;
 114         int ret;
 115
 116         IRDA_ASSERT(self != NULL, return;);
 117         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 118
 119         /* Allocate frame */
 120         tx_skb = alloc_skb(sizeof(struct snrm_frame) +
 121                            IRLAP_NEGOCIATION_PARAMS_LEN,
 122                            GFP_ATOMIC);
 123         if (!tx_skb)
 124                 return;
 125
 126         frame = (struct snrm_frame *) skb_put(tx_skb, 2);
 127
 128         /* Insert connection address field */
 129         if (qos)
 130                 frame->caddr = CMD_FRAME | CBROADCAST;
 131         else
 132                 frame->caddr = CMD_FRAME | self->caddr;
 133
 134         /* Insert control field */
 135         frame->control = SNRM_CMD | PF_BIT;
 136
 137         /*
 138          *  If we are establishing a connection then insert QoS paramerters
 139          */
 140         if (qos) {
 141                 skb_put(tx_skb, 9); /* 25 left */
 142                 frame->saddr = cpu_to_le32(self->saddr);
 143                 frame->daddr = cpu_to_le32(self->daddr);
 144
 145                 frame->ncaddr = self->caddr;
 146
 147                 ret = irlap_insert_qos_negotiation_params(self, tx_skb);
 148                 if (ret < 0) {
 149                         dev_kfree_skb(tx_skb);
 150                         return;
 151                 }
 152         }
 153         irlap_queue_xmit(self, tx_skb);
 154 }
 155
 156 /*
 157  * Function irlap_recv_snrm_cmd (skb, info)
 158  *
 159  *    Received SNRM (Set Normal Response Mode) command frame
 160  *
 161  */
 162 static void irlap_recv_snrm_cmd(struct irlap_cb *self, struct sk_buff *skb,
 163                                 struct irlap_info *info)
 164 {
 165         struct snrm_frame *frame;
 166
 167         if (pskb_may_pull(skb,sizeof(struct snrm_frame))) {
 168                 frame = (struct snrm_frame *) skb->data;
 169
 170                 /* Copy the new connection address ignoring the C/R bit */
 171                 info->caddr = frame->ncaddr & 0xFE;
 172
 173                 /* Check if the new connection address is valid */
 174                 if ((info->caddr == 0x00) || (info->caddr == 0xfe)) {
 175                         IRDA_DEBUG(3, "%s(), invalid connection address!\n",
 176                                    __FUNCTION__);
 177                         return;
 178                 }
 179
 180                 /* Copy peer device address */
 181                 info->daddr = le32_to_cpu(frame->saddr);
 182                 info->saddr = le32_to_cpu(frame->daddr);
 183
 184                 /* Only accept if addressed directly to us */
 185                 if (info->saddr != self->saddr) {
 186                         IRDA_DEBUG(2, "%s(), not addressed to us!\n",
 187                                    __FUNCTION__);
 188                         return;
 189                 }
 190                 irlap_do_event(self, RECV_SNRM_CMD, skb, info);
 191         } else {
 192                 /* Signal that this SNRM frame does not contain and I-field */
 193                 irlap_do_event(self, RECV_SNRM_CMD, skb, NULL);
 194         }
 195 }
 196
 197 /*
 198  * Function irlap_send_ua_response_frame (qos)
 199  *
 200  *    Send UA (Unnumbered Acknowledgement) frame
 201  *
 202  */
 203 void irlap_send_ua_response_frame(struct irlap_cb *self, struct qos_info *qos)
 204 {
 205         struct sk_buff *tx_skb;
 206         struct ua_frame *frame;
 207         int ret;
 208
 209         IRDA_DEBUG(2, "%s() <%ld>\n", __FUNCTION__, jiffies);
 210
 211         IRDA_ASSERT(self != NULL, return;);
 212         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 213
 214         /* Allocate frame */
 215         tx_skb = alloc_skb(sizeof(struct ua_frame) +
 216                            IRLAP_NEGOCIATION_PARAMS_LEN,
 217                            GFP_ATOMIC);
 218         if (!tx_skb)
 219                 return;
 220
 221         frame = (struct ua_frame *) skb_put(tx_skb, 10);
 222
 223         /* Build UA response */
 224         frame->caddr = self->caddr;
 225         frame->control = UA_RSP | PF_BIT;
 226
 227         frame->saddr = cpu_to_le32(self->saddr);
 228         frame->daddr = cpu_to_le32(self->daddr);
 229
 230         /* Should we send QoS negotiation parameters? */
 231         if (qos) {
 232                 ret = irlap_insert_qos_negotiation_params(self, tx_skb);
 233                 if (ret < 0) {
 234                         dev_kfree_skb(tx_skb);
 235                         return;
 236                 }
 237         }
 238
 239         irlap_queue_xmit(self, tx_skb);
 240 }
 241
 242
 243 /*
 244  * Function irlap_send_dm_frame (void)
 245  *
 246  *    Send disconnected mode (DM) frame
 247  *
 248  */
 249 void irlap_send_dm_frame( struct irlap_cb *self)
 250 {
 251         struct sk_buff *tx_skb = NULL;
 252         struct dm_frame *frame;
 253
 254         IRDA_ASSERT(self != NULL, return;);
 255         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 256
 257         tx_skb = alloc_skb(sizeof(struct dm_frame), GFP_ATOMIC);
 258         if (!tx_skb)
 259                 return;
 260
 261         frame = (struct dm_frame *)skb_put(tx_skb, 2);
 262
 263         if (self->state == LAP_NDM)
 264                 frame->caddr = CBROADCAST;
 265         else
 266                 frame->caddr = self->caddr;
 267
 268         frame->control = DM_RSP | PF_BIT;
 269
 270         irlap_queue_xmit(self, tx_skb);
 271 }
 272
 273 /*
 274  * Function irlap_send_disc_frame (void)
 275  *
 276  *    Send disconnect (DISC) frame
 277  *
 278  */
 279 void irlap_send_disc_frame(struct irlap_cb *self)
 280 {
 281         struct sk_buff *tx_skb = NULL;
 282         struct disc_frame *frame;
 283
 284         IRDA_DEBUG(3, "%s()\n", __FUNCTION__);
 285
 286         IRDA_ASSERT(self != NULL, return;);
 287         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 288
 289         tx_skb = alloc_skb(sizeof(struct disc_frame), GFP_ATOMIC);
 290         if (!tx_skb)
 291                 return;
 292
 293         frame = (struct disc_frame *)skb_put(tx_skb, 2);
 294
 295         frame->caddr = self->caddr | CMD_FRAME;
 296         frame->control = DISC_CMD | PF_BIT;
 297
 298         irlap_queue_xmit(self, tx_skb);
 299 }
 300
 301 /*
 302  * Function irlap_send_discovery_xid_frame (S, s, command)
 303  *
 304  *    Build and transmit a XID (eXchange station IDentifier) discovery
 305  *    frame.
 306  */
 307 void irlap_send_discovery_xid_frame(struct irlap_cb *self, int S, __u8 s,
 308                                     __u8 command, discovery_t *discovery)
 309 {
 310         struct sk_buff *tx_skb = NULL;
 311         struct xid_frame *frame;
 312         __u32 bcast = BROADCAST;
 313         __u8 *info;
 314
 315         IRDA_DEBUG(4, "%s(), s=%d, S=%d, command=%d\n", __FUNCTION__,
 316                    s, S, command);
 317
 318         IRDA_ASSERT(self != NULL, return;);
 319         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 320         IRDA_ASSERT(discovery != NULL, return;);
 321
 322         tx_skb = alloc_skb(sizeof(struct xid_frame) + IRLAP_DISCOVERY_INFO_LEN,
 323                            GFP_ATOMIC);
 324         if (!tx_skb)
 325                 return;
 326
 327         skb_put(tx_skb, 14);
 328         frame = (struct xid_frame *) tx_skb->data;
 329
 330         if (command) {
 331                 frame->caddr = CBROADCAST | CMD_FRAME;
 332                 frame->control =  XID_CMD | PF_BIT;
 333         } else {
 334                 frame->caddr = CBROADCAST;
 335                 frame->control =  XID_RSP | PF_BIT;
 336         }
 337         frame->ident = XID_FORMAT;
 338
 339         frame->saddr = cpu_to_le32(self->saddr);
 340
 341         if (command)
 342                 frame->daddr = cpu_to_le32(bcast);
 343         else
 344                 frame->daddr = cpu_to_le32(discovery->data.daddr);
 345
 346         switch (S) {
 347         case 1:
 348                 frame->flags = 0x00;
 349                 break;
 350         case 6:
 351                 frame->flags = 0x01;
 352                 break;
 353         case 8:
 354                 frame->flags = 0x02;
 355                 break;
 356         case 16:
 357                 frame->flags = 0x03;
 358                 break;
 359         default:
 360                 frame->flags = 0x02;
 361                 break;
 362         }
 363
 364         frame->slotnr = s;
 365         frame->version = 0x00;
 366
 367         /*
 368          *  Provide info for final slot only in commands, and for all
 369          *  responses. Send the second byte of the hint only if the
 370          *  EXTENSION bit is set in the first byte.
 371          */
 372         if (!command || (frame->slotnr == 0xff)) {
 373                 int len;
 374
 375                 if (discovery->data.hints[0] & HINT_EXTENSION) {
 376                         info = skb_put(tx_skb, 2);
 377                         info[0] = discovery->data.hints[0];
 378                         info[1] = discovery->data.hints[1];
 379                 } else {
 380                         info = skb_put(tx_skb, 1);
 381                         info[0] = discovery->data.hints[0];
 382                 }
 383                 info = skb_put(tx_skb, 1);
 384                 info[0] = discovery->data.charset;
 385
 386                 len = IRDA_MIN(discovery->name_len, skb_tailroom(tx_skb));
 387                 info = skb_put(tx_skb, len);
 388                 memcpy(info, discovery->data.info, len);
 389         }
 390         irlap_queue_xmit(self, tx_skb);
 391 }
 392
 393 /*
 394  * Function irlap_recv_discovery_xid_rsp (skb, info)
 395  *
 396  *    Received a XID discovery response
 397  *
 398  */
 399 static void irlap_recv_discovery_xid_rsp(struct irlap_cb *self,
 400                                          struct sk_buff *skb,
 401                                          struct irlap_info *info)
 402 {
 403         struct xid_frame *xid;
 404         discovery_t *discovery = NULL;
 405         __u8 *discovery_info;
 406         char *text;
 407
 408         IRDA_DEBUG(4, "%s()\n", __FUNCTION__);
 409
 410         IRDA_ASSERT(self != NULL, return;);
 411         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 412
 413         if (!pskb_may_pull(skb, sizeof(struct xid_frame))) {
 414                 IRDA_ERROR("%s: frame to short!\n", __FUNCTION__);
 415                 return;
 416         }
 417
 418         xid = (struct xid_frame *) skb->data;
 419
 420         info->daddr = le32_to_cpu(xid->saddr);
 421         info->saddr = le32_to_cpu(xid->daddr);
 422
 423         /* Make sure frame is addressed to us */
 424         if ((info->saddr != self->saddr) && (info->saddr != BROADCAST)) {
 425                 IRDA_DEBUG(0, "%s(), frame is not addressed to us!\n",
 426                            __FUNCTION__);
 427                 return;
 428         }
 429
 430         if ((discovery = kzalloc(sizeof(discovery_t), GFP_ATOMIC)) == NULL) {
 431                 IRDA_WARNING("%s: kmalloc failed!\n", __FUNCTION__);
 432                 return;
 433         }
 434
 435         discovery->data.daddr = info->daddr;
 436         discovery->data.saddr = self->saddr;
 437         discovery->timestamp = jiffies;
 438
 439         IRDA_DEBUG(4, "%s(), daddr=%08x\n", __FUNCTION__,
 440                    discovery->data.daddr);
 441
 442         discovery_info = skb_pull(skb, sizeof(struct xid_frame));
 443
 444         /* Get info returned from peer */
 445         discovery->data.hints[0] = discovery_info[0];
 446         if (discovery_info[0] & HINT_EXTENSION) {
 447                 IRDA_DEBUG(4, "EXTENSION\n");
 448                 discovery->data.hints[1] = discovery_info[1];
 449                 discovery->data.charset = discovery_info[2];
 450                 text = (char *) &discovery_info[3];
 451         } else {
 452                 discovery->data.hints[1] = 0;
 453                 discovery->data.charset = discovery_info[1];
 454                 text = (char *) &discovery_info[2];
 455         }
 456         /*
 457          *  Terminate info string, should be safe since this is where the
 458          *  FCS bytes resides.
 459          */
 460         skb->data[skb->len] = '\0';
 461         strncpy(discovery->data.info, text, NICKNAME_MAX_LEN);
 462         discovery->name_len = strlen(discovery->data.info);
 463
 464         info->discovery = discovery;
 465
 466         irlap_do_event(self, RECV_DISCOVERY_XID_RSP, skb, info);
 467 }
 468
 469 /*
 470  * Function irlap_recv_discovery_xid_cmd (skb, info)
 471  *
 472  *    Received a XID discovery command
 473  *
 474  */
 475 static void irlap_recv_discovery_xid_cmd(struct irlap_cb *self,
 476                                          struct sk_buff *skb,
 477                                          struct irlap_info *info)
 478 {
 479         struct xid_frame *xid;
 480         discovery_t *discovery = NULL;
 481         __u8 *discovery_info;
 482         char *text;
 483
 484         if (!pskb_may_pull(skb, sizeof(struct xid_frame))) {
 485                 IRDA_ERROR("%s: frame to short!\n", __FUNCTION__);
 486                 return;
 487         }
 488
 489         xid = (struct xid_frame *) skb->data;
 490
 491         info->daddr = le32_to_cpu(xid->saddr);
 492         info->saddr = le32_to_cpu(xid->daddr);
 493
 494         /* Make sure frame is addressed to us */
 495         if ((info->saddr != self->saddr) && (info->saddr != BROADCAST)) {
 496                 IRDA_DEBUG(0, "%s(), frame is not addressed to us!\n",
 497                            __FUNCTION__);
 498                 return;
 499         }
 500
 501         switch (xid->flags & 0x03) {
 502         case 0x00:
 503                 info->S = 1;
 504                 break;
 505         case 0x01:
 506                 info->S = 6;
 507                 break;
 508         case 0x02:
 509                 info->S = 8;
 510                 break;
 511         case 0x03:
 512                 info->S = 16;
 513                 break;
 514         default:
 515                 /* Error!! */
 516                 return;
 517         }
 518         info->s = xid->slotnr;
 519
 520         discovery_info = skb_pull(skb, sizeof(struct xid_frame));
 521
 522         /*
 523          *  Check if last frame
 524          */
 525         if (info->s == 0xff) {
 526                 /* Check if things are sane at this point... */
 527                 if((discovery_info == NULL) ||
 528                    !pskb_may_pull(skb, 3)) {
 529                         IRDA_ERROR("%s: discovery frame to short!\n",
 530                                    __FUNCTION__);
 531                         return;
 532                 }
 533
 534                 /*
 535                  *  We now have some discovery info to deliver!
 536                  */
 537                 discovery = kmalloc(sizeof(discovery_t), GFP_ATOMIC);
 538                 if (!discovery) {
 539                         IRDA_WARNING("%s: unable to malloc!\n", __FUNCTION__);
 540                         return;
 541                 }
 542
 543                 discovery->data.daddr = info->daddr;
 544                 discovery->data.saddr = self->saddr;
 545                 discovery->timestamp = jiffies;
 546
 547                 discovery->data.hints[0] = discovery_info[0];
 548                 if (discovery_info[0] & HINT_EXTENSION) {
 549                         discovery->data.hints[1] = discovery_info[1];
 550                         discovery->data.charset = discovery_info[2];
 551                         text = (char *) &discovery_info[3];
 552                 } else {
 553                         discovery->data.hints[1] = 0;
 554                         discovery->data.charset = discovery_info[1];
 555                         text = (char *) &discovery_info[2];
 556                 }
 557                 /*
 558                  *  Terminate string, should be safe since this is where the
 559                  *  FCS bytes resides.
 560                  */
 561                 skb->data[skb->len] = '\0';
 562                 strncpy(discovery->data.info, text, NICKNAME_MAX_LEN);
 563                 discovery->name_len = strlen(discovery->data.info);
 564
 565                 info->discovery = discovery;
 566         } else
 567                 info->discovery = NULL;
 568
 569         irlap_do_event(self, RECV_DISCOVERY_XID_CMD, skb, info);
 570 }
 571
 572 /*
 573  * Function irlap_send_rr_frame (self, command)
 574  *
 575  *    Build and transmit RR (Receive Ready) frame. Notice that it is currently
 576  *    only possible to send RR frames with the poll bit set.
 577  */
 578 void irlap_send_rr_frame(struct irlap_cb *self, int command)
 579 {
 580         struct sk_buff *tx_skb;
 581         struct rr_frame *frame;
 582
 583         tx_skb = alloc_skb(sizeof(struct rr_frame), GFP_ATOMIC);
 584         if (!tx_skb)
 585                 return;
 586
 587         frame = (struct rr_frame *)skb_put(tx_skb, 2);
 588
 589         frame->caddr = self->caddr;
 590         frame->caddr |= (command) ? CMD_FRAME : 0;
 591
 592         frame->control = RR | PF_BIT | (self->vr << 5);
 593
 594         irlap_queue_xmit(self, tx_skb);
 595 }
 596
 597 /*
 598  * Function irlap_send_rd_frame (self)
 599  *
 600  *    Request disconnect. Used by a secondary station to request the
 601  *    disconnection of the link.
 602  */
 603 void irlap_send_rd_frame(struct irlap_cb *self)
 604 {
 605         struct sk_buff *tx_skb;
 606         struct rd_frame *frame;
 607
 608         tx_skb = alloc_skb(sizeof(struct rd_frame), GFP_ATOMIC);
 609         if (!tx_skb)
 610                 return;
 611
 612         frame = (struct rd_frame *)skb_put(tx_skb, 2);
 613
 614         frame->caddr = self->caddr;
 615         frame->caddr = RD_RSP | PF_BIT;
 616
 617         irlap_queue_xmit(self, tx_skb);
 618 }
 619
 620 /*
 621  * Function irlap_recv_rr_frame (skb, info)
 622  *
 623  *    Received RR (Receive Ready) frame from peer station, no harm in
 624  *    making it inline since its called only from one single place
 625  *    (irlap_driver_rcv).
 626  */
 627 static inline void irlap_recv_rr_frame(struct irlap_cb *self,
 628                                        struct sk_buff *skb,
 629                                        struct irlap_info *info, int command)
 630 {
 631         info->nr = skb->data[1] >> 5;
 632
 633         /* Check if this is a command or a response frame */
 634         if (command)
 635                 irlap_do_event(self, RECV_RR_CMD, skb, info);
 636         else
 637                 irlap_do_event(self, RECV_RR_RSP, skb, info);
 638 }
 639
 640 /*
 641  * Function irlap_recv_rnr_frame (self, skb, info)
 642  *
 643  *    Received RNR (Receive Not Ready) frame from peer station
 644  *
 645  */
 646 static void irlap_recv_rnr_frame(struct irlap_cb *self, struct sk_buff *skb,
 647                                  struct irlap_info *info, int command)
 648 {
 649         info->nr = skb->data[1] >> 5;
 650
 651         IRDA_DEBUG(4, "%s(), nr=%d, %ld\n", __FUNCTION__, info->nr, jiffies);
 652
 653         if (command)
 654                 irlap_do_event(self, RECV_RNR_CMD, skb, info);
 655         else
 656                 irlap_do_event(self, RECV_RNR_RSP, skb, info);
 657 }
 658
 659 static void irlap_recv_rej_frame(struct irlap_cb *self, struct sk_buff *skb,
 660                                  struct irlap_info *info, int command)
 661 {
 662         IRDA_DEBUG(0, "%s()\n", __FUNCTION__);
 663
 664         info->nr = skb->data[1] >> 5;
 665
 666         /* Check if this is a command or a response frame */
 667         if (command)
 668                 irlap_do_event(self, RECV_REJ_CMD, skb, info);
 669         else
 670                 irlap_do_event(self, RECV_REJ_RSP, skb, info);
 671 }
 672
 673 static void irlap_recv_srej_frame(struct irlap_cb *self, struct sk_buff *skb,
 674                                   struct irlap_info *info, int command)
 675 {
 676         IRDA_DEBUG(0, "%s()\n", __FUNCTION__);
 677
 678         info->nr = skb->data[1] >> 5;
 679
 680         /* Check if this is a command or a response frame */
 681         if (command)
 682                 irlap_do_event(self, RECV_SREJ_CMD, skb, info);
 683         else
 684                 irlap_do_event(self, RECV_SREJ_RSP, skb, info);
 685 }
 686
 687 static void irlap_recv_disc_frame(struct irlap_cb *self, struct sk_buff *skb,
 688                                   struct irlap_info *info, int command)
 689 {
 690         IRDA_DEBUG(2, "%s()\n", __FUNCTION__);
 691
 692         /* Check if this is a command or a response frame */
 693         if (command)
 694                 irlap_do_event(self, RECV_DISC_CMD, skb, info);
 695         else
 696                 irlap_do_event(self, RECV_RD_RSP, skb, info);
 697 }
 698
 699 /*
 700  * Function irlap_recv_ua_frame (skb, frame)
 701  *
 702  *    Received UA (Unnumbered Acknowledgement) frame
 703  *
 704  */
 705 static inline void irlap_recv_ua_frame(struct irlap_cb *self,
 706                                        struct sk_buff *skb,
 707                                        struct irlap_info *info)
 708 {
 709         irlap_do_event(self, RECV_UA_RSP, skb, info);
 710 }
 711
 712 /*
 713  * Function irlap_send_data_primary(self, skb)
 714  *
 715  *    Send I-frames as the primary station but without the poll bit set
 716  *
 717  */
 718 void irlap_send_data_primary(struct irlap_cb *self, struct sk_buff *skb)
 719 {
 720         struct sk_buff *tx_skb;
 721
 722         if (skb->data[1] == I_FRAME) {
 723
 724                 /*
 725                  *  Insert frame sequence number (Vs) in control field before
 726                  *  inserting into transmit window queue.
 727                  */
 728                 skb->data[1] = I_FRAME | (self->vs << 1);
 729
 730                 /*
 731                  *  Insert frame in store, in case of retransmissions
 732                  *  Increase skb reference count, see irlap_do_event()
 733                  */
 734                 skb_get(skb);
 735                 skb_queue_tail(&self->wx_list, skb);
 736
 737                 /* Copy buffer */
 738                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 739                 if (tx_skb == NULL) {
 740                         return;
 741                 }
 742
 743                 self->vs = (self->vs + 1) % 8;
 744                 self->ack_required = FALSE;
 745                 self->window -= 1;
 746
 747                 irlap_send_i_frame( self, tx_skb, CMD_FRAME);
 748         } else {
 749                 IRDA_DEBUG(4, "%s(), sending unreliable frame\n", __FUNCTION__);
 750                 irlap_send_ui_frame(self, skb_get(skb), self->caddr, CMD_FRAME);
 751                 self->window -= 1;
 752         }
 753 }
 754 /*
 755  * Function irlap_send_data_primary_poll (self, skb)
 756  *
 757  *    Send I(nformation) frame as primary with poll bit set
 758  */
 759 void irlap_send_data_primary_poll(struct irlap_cb *self, struct sk_buff *skb)
 760 {
 761         struct sk_buff *tx_skb;
 762         int transmission_time;
 763
 764         /* Stop P timer */
 765         del_timer(&self->poll_timer);
 766
 767         /* Is this reliable or unreliable data? */
 768         if (skb->data[1] == I_FRAME) {
 769
 770                 /*
 771                  *  Insert frame sequence number (Vs) in control field before
 772                  *  inserting into transmit window queue.
 773                  */
 774                 skb->data[1] = I_FRAME | (self->vs << 1);
 775
 776                 /*
 777                  *  Insert frame in store, in case of retransmissions
 778                  *  Increase skb reference count, see irlap_do_event()
 779                  */
 780                 skb_get(skb);
 781                 skb_queue_tail(&self->wx_list, skb);
 782
 783                 /* Copy buffer */
 784                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 785                 if (tx_skb == NULL) {
 786                         return;
 787                 }
 788
 789                 /*
 790                  *  Set poll bit if necessary. We do this to the copied
 791                  *  skb, since retransmitted need to set or clear the poll
 792                  *  bit depending on when they are sent.
 793                  */
 794                 tx_skb->data[1] |= PF_BIT;
 795
 796                 self->vs = (self->vs + 1) % 8;
 797                 self->ack_required = FALSE;
 798
 799                 irlap_send_i_frame(self, tx_skb, CMD_FRAME);
 800         } else {
 801                 IRDA_DEBUG(4, "%s(), sending unreliable frame\n", __FUNCTION__);
 802
 803                 if (self->ack_required) {
 804                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, CMD_FRAME);
 805                         irlap_send_rr_frame(self, CMD_FRAME);
 806                         self->ack_required = FALSE;
 807                 } else {
 808                         skb->data[1] |= PF_BIT;
 809                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, CMD_FRAME);
 810                 }
 811         }
 812
 813         /* How much time we took for transmission of all frames.
 814          * We don't know, so let assume we used the full window. Jean II */
 815         transmission_time = self->final_timeout;
 816
 817         /* Reset parameter so that we can fill next window */
 818         self->window = self->window_size;
 819
 820 #ifdef CONFIG_IRDA_DYNAMIC_WINDOW
 821         /* Remove what we have not used. Just do a prorata of the
 822          * bytes left in window to window capacity.
 823          * See max_line_capacities[][] in qos.c for details. Jean II */
 824         transmission_time -= (self->final_timeout * self->bytes_left
 825                               / self->line_capacity);
 826         IRDA_DEBUG(4, "%s() adjusting transmission_time : ft=%d, bl=%d, lc=%d -> tt=%d\n", __FUNCTION__, self->final_timeout, self->bytes_left, self->line_capacity, transmission_time);
 827
 828         /* We are allowed to transmit a maximum number of bytes again. */
 829         self->bytes_left = self->line_capacity;
 830 #endif /* CONFIG_IRDA_DYNAMIC_WINDOW */
 831
 832         /*
 833          * The network layer has a intermediate buffer between IrLAP
 834          * and the IrDA driver which can contain 8 frames. So, even
 835          * though IrLAP is currently sending the *last* frame of the
 836          * tx-window, the driver most likely has only just started
 837          * sending the *first* frame of the same tx-window.
 838          * I.e. we are always at the very begining of or Tx window.
 839          * Now, we are supposed to set the final timer from the end
 840          * of our tx-window to let the other peer reply. So, we need
 841          * to add extra time to compensate for the fact that we
 842          * are really at the start of tx-window, otherwise the final timer
 843          * might expire before he can answer...
 844          * Jean II
 845          */
 846         irlap_start_final_timer(self, self->final_timeout + transmission_time);
 847
 848         /*
 849          * The clever amongst you might ask why we do this adjustement
 850          * only here, and not in all the other cases in irlap_event.c.
 851          * In all those other case, we only send a very short management
 852          * frame (few bytes), so the adjustement would be lost in the
 853          * noise...
 854          * The exception of course is irlap_resend_rejected_frame().
 855          * Jean II */
 856 }
 857
 858 /*
 859  * Function irlap_send_data_secondary_final (self, skb)
 860  *
 861  *    Send I(nformation) frame as secondary with final bit set
 862  *
 863  */
 864 void irlap_send_data_secondary_final(struct irlap_cb *self,
 865                                      struct sk_buff *skb)
 866 {
 867         struct sk_buff *tx_skb = NULL;
 868
 869         IRDA_ASSERT(self != NULL, return;);
 870         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 871         IRDA_ASSERT(skb != NULL, return;);
 872
 873         /* Is this reliable or unreliable data? */
 874         if (skb->data[1] == I_FRAME) {
 875
 876                 /*
 877                  *  Insert frame sequence number (Vs) in control field before
 878                  *  inserting into transmit window queue.
 879                  */
 880                 skb->data[1] = I_FRAME | (self->vs << 1);
 881
 882                 /*
 883                  *  Insert frame in store, in case of retransmissions
 884                  *  Increase skb reference count, see irlap_do_event()
 885                  */
 886                 skb_get(skb);
 887                 skb_queue_tail(&self->wx_list, skb);
 888
 889                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 890                 if (tx_skb == NULL) {
 891                         return;
 892                 }
 893
 894                 tx_skb->data[1] |= PF_BIT;
 895
 896                 self->vs = (self->vs + 1) % 8;
 897                 self->ack_required = FALSE;
 898
 899                 irlap_send_i_frame(self, tx_skb, RSP_FRAME);
 900         } else {
 901                 if (self->ack_required) {
 902                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, RSP_FRAME);
 903                         irlap_send_rr_frame(self, RSP_FRAME);
 904                         self->ack_required = FALSE;
 905                 } else {
 906                         skb->data[1] |= PF_BIT;
 907                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, RSP_FRAME);
 908                 }
 909         }
 910
 911         self->window = self->window_size;
 912 #ifdef CONFIG_IRDA_DYNAMIC_WINDOW
 913         /* We are allowed to transmit a maximum number of bytes again. */
 914         self->bytes_left = self->line_capacity;
 915 #endif /* CONFIG_IRDA_DYNAMIC_WINDOW */
 916
 917         irlap_start_wd_timer(self, self->wd_timeout);
 918 }
 919
 920 /*
 921  * Function irlap_send_data_secondary (self, skb)
 922  *
 923  *    Send I(nformation) frame as secondary without final bit set
 924  *
 925  */
 926 void irlap_send_data_secondary(struct irlap_cb *self, struct sk_buff *skb)
 927 {
 928         struct sk_buff *tx_skb = NULL;
 929
 930         /* Is this reliable or unreliable data? */
 931         if (skb->data[1] == I_FRAME) {
 932
 933                 /*
 934                  *  Insert frame sequence number (Vs) in control field before
 935                  *  inserting into transmit window queue.
 936                  */
 937                 skb->data[1] = I_FRAME | (self->vs << 1);
 938
 939                 /*
 940                  *  Insert frame in store, in case of retransmissions
 941                  *  Increase skb reference count, see irlap_do_event()
 942                  */
 943                 skb_get(skb);
 944                 skb_queue_tail(&self->wx_list, skb);
 945
 946                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 947                 if (tx_skb == NULL) {
 948                         return;
 949                 }
 950
 951                 self->vs = (self->vs + 1) % 8;
 952                 self->ack_required = FALSE;
 953                 self->window -= 1;
 954
 955                 irlap_send_i_frame(self, tx_skb, RSP_FRAME);
 956         } else {
 957                 irlap_send_ui_frame(self, skb_get(skb), self->caddr, RSP_FRAME);
 958                 self->window -= 1;
 959         }
 960 }
 961
 962 /*
 963  * Function irlap_resend_rejected_frames (nr)
 964  *
 965  *    Resend frames which has not been acknowledged. Should be safe to
 966  *    traverse the list without locking it since this function will only be
 967  *    called from interrupt context (BH)
 968  */
 969 void irlap_resend_rejected_frames(struct irlap_cb *self, int command)
 970 {
 971         struct sk_buff *tx_skb;
 972         struct sk_buff *skb;
 973         int count;
 974
 975         IRDA_ASSERT(self != NULL, return;);
 976         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 977
 978         /* Initialize variables */
 979         count = skb_queue_len(&self->wx_list);
 980
 981         /*  Resend unacknowledged frame(s) */
 982         skb = skb_peek(&self->wx_list);
 983         while (skb != NULL) {
 984                 irlap_wait_min_turn_around(self, &self->qos_tx);
 985
 986                 /* We copy the skb to be retransmitted since we will have to
 987                  * modify it. Cloning will confuse packet sniffers
 988                  */
 989                 /* tx_skb = skb_clone( skb, GFP_ATOMIC); */
 990                 tx_skb = skb_copy(skb, GFP_ATOMIC);
 991                 if (!tx_skb) {
 992                         IRDA_DEBUG(0, "%s(), unable to copy\n", __FUNCTION__);
 993                         return;
 994                 }
 995
 996                 /* Clear old Nr field + poll bit */
 997                 tx_skb->data[1] &= 0x0f;
 998
 999                 /*
1000                  *  Set poll bit on the last frame retransmitted
1001                  */
1002                 if (count-- == 1)
1003                         tx_skb->data[1] |= PF_BIT; /* Set p/f bit */
1004                 else
1005                         tx_skb->data[1] &= ~PF_BIT; /* Clear p/f bit */
1006
1007                 irlap_send_i_frame(self, tx_skb, command);
1008
1009                 /*
1010                  *  If our skb is the last buffer in the list, then
1011                  *  we are finished, if not, move to the next sk-buffer
1012                  */
1013                 if (skb == skb_peek_tail(&self->wx_list))
1014                         skb = NULL;
1015                 else
1016                         skb = skb->next;
1017         }
1018 #if 0 /* Not yet */
1019         /*
1020          *  We can now fill the window with additional data frames
1021          */
1022         while (!skb_queue_empty(&self->txq)) {
1023
1024                 IRDA_DEBUG(0, "%s(), sending additional frames!\n", __FUNCTION__);
1025                 if (self->window > 0) {
1026                         skb = skb_dequeue( &self->txq);
1027                         IRDA_ASSERT(skb != NULL, return;);
1028
1029                         /*
1030                          *  If send window > 1 then send frame with pf
1031                          *  bit cleared
1032                          */
1033                         if ((self->window > 1) &&
1034                             !skb_queue_empty(&self->txq)) {
1035                                 irlap_send_data_primary(self, skb);
1036                         } else {
1037                                 irlap_send_data_primary_poll(self, skb);
1038                         }
1039                         kfree_skb(skb);
1040                 }
1041         }
1042 #endif
1043 }
1044
1045 void irlap_resend_rejected_frame(struct irlap_cb *self, int command)
1046 {
1047         struct sk_buff *tx_skb;
1048         struct sk_buff *skb;
1049
1050         IRDA_ASSERT(self != NULL, return;);
1051         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
1052
1053         /*  Resend unacknowledged frame(s) */
1054         skb = skb_peek(&self->wx_list);
1055         if (skb != NULL) {
1056                 irlap_wait_min_turn_around(self, &self->qos_tx);
1057
1058                 /* We copy the skb to be retransmitted since we will have to
1059                  * modify it. Cloning will confuse packet sniffers
1060                  */
1061                 /* tx_skb = skb_clone( skb, GFP_ATOMIC); */
1062                 tx_skb = skb_copy(skb, GFP_ATOMIC);
1063                 if (!tx_skb) {
1064                         IRDA_DEBUG(0, "%s(), unable to copy\n", __FUNCTION__);
1065                         return;
1066                 }
1067
1068                 /* Clear old Nr field + poll bit */
1069                 tx_skb->data[1] &= 0x0f;
1070
1071                 /*  Set poll/final bit */
1072                 tx_skb->data[1] |= PF_BIT; /* Set p/f bit */
1073
1074                 irlap_send_i_frame(self, tx_skb, command);
1075         }
1076 }
1077
1078 /*
1079  * Function irlap_send_ui_frame (self, skb, command)
1080  *
1081  *    Contruct and transmit an Unnumbered Information (UI) frame
1082  *
1083  */
1084 void irlap_send_ui_frame(struct irlap_cb *self, struct sk_buff *skb,
1085                          __u8 caddr, int command)
1086 {
1087         IRDA_DEBUG(4, "%s()\n", __FUNCTION__);
1088
1089         IRDA_ASSERT(self != NULL, return;);
1090         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
1091         IRDA_ASSERT(skb != NULL, return;);
1092
1093         /* Insert connection address */
1094         skb->data[0] = caddr | ((command) ? CMD_FRAME : 0);
1095
1096         irlap_queue_xmit(self, skb);
1097 }
1098
1099 /*
1100  * Function irlap_send_i_frame (skb)
1101  *
1102  *    Contruct and transmit Information (I) frame
1103  */
1104 static void irlap_send_i_frame(struct irlap_cb *self, struct sk_buff *skb,
1105                                int command)
1106 {
1107         /* Insert connection address */
1108         skb->data[0] = self->caddr;
1109         skb->data[0] |= (command) ? CMD_FRAME : 0;
1110
1111         /* Insert next to receive (Vr) */
1112         skb->data[1] |= (self->vr << 5);  /* insert nr */
1113
1114         irlap_queue_xmit(self, skb);
1115 }
1116
1117 /*
1118  * Function irlap_recv_i_frame (skb, frame)
1119  *
1120  *    Receive and parse an I (Information) frame, no harm in making it inline
1121  *    since it's called only from one single place (irlap_driver_rcv).
1122  */
1123 static inline void irlap_recv_i_frame(struct irlap_cb *self,
1124                                       struct sk_buff *skb,
1125                                       struct irlap_info *info, int command)
1126 {
1127         info->nr = skb->data[1] >> 5;          /* Next to receive */
1128         info->pf = skb->data[1] & PF_BIT;      /* Final bit */
1129         info->ns = (skb->data[1] >> 1) & 0x07; /* Next to send */
1130
1131         /* Check if this is a command or a response frame */
1132         if (command)
1133                 irlap_do_event(self, RECV_I_CMD, skb, info);
1134         else
1135                 irlap_do_event(self, RECV_I_RSP, skb, info);
1136 }
1137
1138 /*
1139  * Function irlap_recv_ui_frame (self, skb, info)
1140  *
1141  *    Receive and parse an Unnumbered Information (UI) frame
1142  *
1143  */
1144 static void irlap_recv_ui_frame(struct irlap_cb *self, struct sk_buff *skb,
1145                                 struct irlap_info *info)
1146 {
1147         IRDA_DEBUG( 4, "%s()\n", __FUNCTION__);
1148
1149         info->pf = skb->data[1] & PF_BIT;      /* Final bit */
1150
1151         irlap_do_event(self, RECV_UI_FRAME, skb, info);
1152 }
1153
1154 /*
1155  * Function irlap_recv_frmr_frame (skb, frame)
1156  *
1157  *    Received Frame Reject response.
1158  *
1159  */
1160 static void irlap_recv_frmr_frame(struct irlap_cb *self, struct sk_buff *skb,
1161                                   struct irlap_info *info)
1162 {
1163         __u8 *frame;
1164         int w, x, y, z;
1165
1166         IRDA_DEBUG(0, "%s()\n", __FUNCTION__);
1167
1168         IRDA_ASSERT(self != NULL, return;);
1169         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
1170         IRDA_ASSERT(skb != NULL, return;);
1171         IRDA_ASSERT(info != NULL, return;);
1172
1173         if (!pskb_may_pull(skb, 4)) {
1174                 IRDA_ERROR("%s: frame to short!\n", __FUNCTION__);
1175                 return;
1176         }
1177
1178         frame = skb->data;
1179
1180         info->nr = frame[2] >> 5;          /* Next to receive */
1181         info->pf = frame[2] & PF_BIT;      /* Final bit */
1182         info->ns = (frame[2] >> 1) & 0x07; /* Next to send */
1183
1184         w = frame[3] & 0x01;
1185         x = frame[3] & 0x02;
1186         y = frame[3] & 0x04;
1187         z = frame[3] & 0x08;
1188
1189         if (w) {
1190                 IRDA_DEBUG(0, "Rejected control field is undefined or not "
1191                       "implemented.\n");
1192         }
1193         if (x) {
1194                 IRDA_DEBUG(0, "Rejected control field was invalid because it "
1195                       "contained a non permitted I field.\n");
1196         }
1197         if (y) {
1198                 IRDA_DEBUG(0, "Received I field exceeded the maximum negotiated "
1199                       "for the existing connection or exceeded the maximum "
1200                       "this station supports if no connection exists.\n");
1201         }
1202         if (z) {
1203                 IRDA_DEBUG(0, "Rejected control field control field contained an "
1204                       "invalid Nr count.\n");
1205         }
1206         irlap_do_event(self, RECV_FRMR_RSP, skb, info);
1207 }
1208
1209 /*
1210  * Function irlap_send_test_frame (self, daddr)
1211  *
1212  *    Send a test frame response
1213  *
1214  */
1215 void irlap_send_test_frame(struct irlap_cb *self, __u8 caddr, __u32 daddr,
1216                            struct sk_buff *cmd)
1217 {
1218         struct sk_buff *tx_skb;
1219         struct test_frame *frame;
1220         __u8 *info;
1221
1222         tx_skb = alloc_skb(cmd->len + sizeof(struct test_frame), GFP_ATOMIC);
1223         if (!tx_skb)
1224                 return;
1225
1226         /* Broadcast frames must include saddr and daddr fields */
1227         if (caddr == CBROADCAST) {
1228                 frame = (struct test_frame *)
1229                         skb_put(tx_skb, sizeof(struct test_frame));
1230
1231                 /* Insert the swapped addresses */
1232                 frame->saddr = cpu_to_le32(self->saddr);
1233                 frame->daddr = cpu_to_le32(daddr);
1234         } else
1235                 frame = (struct test_frame *) skb_put(tx_skb, LAP_ADDR_HEADER + LAP_CTRL_HEADER);
1236
1237         frame->caddr = caddr;
1238         frame->control = TEST_RSP | PF_BIT;
1239
1240         /* Copy info */
1241         info = skb_put(tx_skb, cmd->len);
1242         memcpy(info, cmd->data, cmd->len);
1243
1244         /* Return to sender */
1245         irlap_wait_min_turn_around(self, &self->qos_tx);
1246         irlap_queue_xmit(self, tx_skb);
1247 }
1248
1249 /*
1250  * Function irlap_recv_test_frame (self, skb)
1251  *
1252  *    Receive a test frame
1253  *
1254  */
1255 static void irlap_recv_test_frame(struct irlap_cb *self, struct sk_buff *skb,
1256                                   struct irlap_info *info, int command)
1257 {
1258         struct test_frame *frame;
1259
1260         IRDA_DEBUG(2, "%s()\n", __FUNCTION__);
1261
1262         if (!pskb_may_pull(skb, sizeof(*frame))) {
1263                 IRDA_ERROR("%s: frame to short!\n", __FUNCTION__);
1264                 return;
1265         }
1266         frame = (struct test_frame *) skb->data;
1267
1268         /* Broadcast frames must carry saddr and daddr fields */
1269         if (info->caddr == CBROADCAST) {
1270                 if (skb->len < sizeof(struct test_frame)) {
1271                         IRDA_DEBUG(0, "%s() test frame to short!\n",
1272                                    __FUNCTION__);
1273                         return;
1274                 }
1275
1276                 /* Read and swap addresses */
1277                 info->daddr = le32_to_cpu(frame->saddr);
1278                 info->saddr = le32_to_cpu(frame->daddr);
1279
1280                 /* Make sure frame is addressed to us */
1281                 if ((info->saddr != self->saddr) &&
1282                     (info->saddr != BROADCAST)) {
1283                         return;
1284                 }
1285         }
1286
1287         if (command)
1288                 irlap_do_event(self, RECV_TEST_CMD, skb, info);
1289         else
1290                 irlap_do_event(self, RECV_TEST_RSP, skb, info);
1291 }
1292
1293 /*
1294  * Function irlap_driver_rcv (skb, netdev, ptype)
1295  *
1296  *    Called when a frame is received. Dispatches the right receive function
1297  *    for processing of the frame.
1298  *
1299  * Note on skb management :
1300  * After calling the higher layers of the IrDA stack, we always
1301  * kfree() the skb, which drop the reference count (and potentially
1302  * destroy it).
1303  * If a higher layer of the stack want to keep the skb around (to put
1304  * in a queue or pass it to the higher layer), it will need to use
1305  * skb_get() to keep a reference on it. This is usually done at the
1306  * LMP level in irlmp.c.
1307  * Jean II
1308  */
1309 int irlap_driver_rcv(struct sk_buff *skb, struct net_device *dev,
1310                      struct packet_type *ptype, struct net_device *orig_dev)
1311 {
1312         struct irlap_info info;
1313         struct irlap_cb *self;
1314         int command;
1315         __u8 control;
1316
1317         /* FIXME: should we get our own field? */
1318         self = (struct irlap_cb *) dev->atalk_ptr;
1319
1320         /* If the net device is down, then IrLAP is gone! */
1321         if (!self || self->magic != LAP_MAGIC) {
1322                 dev_kfree_skb(skb);
1323                 return -1;
1324         }
1325
1326         /* We are no longer an "old" protocol, so we need to handle
1327          * share and non linear skbs. This should never happen, so
1328          * we don't need to be clever about it. Jean II */
1329         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
1330                 IRDA_ERROR("%s: can't clone shared skb!\n", __FUNCTION__);
1331                 dev_kfree_skb(skb);
1332                 return -1;
1333         }
1334
1335         /* Check if frame is large enough for parsing */
1336         if (!pskb_may_pull(skb, 2)) {
1337                 IRDA_ERROR("%s: frame to short!\n", __FUNCTION__);
1338                 dev_kfree_skb(skb);
1339                 return -1;
1340         }
1341
1342         command    = skb->data[0] & CMD_FRAME;
1343         info.caddr = skb->data[0] & CBROADCAST;
1344
1345         info.pf      = skb->data[1] &  PF_BIT;
1346         info.control = skb->data[1] & ~PF_BIT; /* Mask away poll/final bit */
1347
1348         control = info.control;
1349
1350         /*  First we check if this frame has a valid connection address */
1351         if ((info.caddr != self->caddr) && (info.caddr != CBROADCAST)) {
1352                 IRDA_DEBUG(0, "%s(), wrong connection address!\n",
1353                            __FUNCTION__);
1354                 goto out;
1355         }
1356         /*
1357          *  Optimize for the common case and check if the frame is an
1358          *  I(nformation) frame. Only I-frames have bit 0 set to 0
1359          */
1360         if (~control & 0x01) {
1361                 irlap_recv_i_frame(self, skb, &info, command);
1362                 goto out;
1363         }
1364         /*
1365          *  We now check is the frame is an S(upervisory) frame. Only
1366          *  S-frames have bit 0 set to 1 and bit 1 set to 0
1367          */
1368         if (~control & 0x02) {
1369                 /*
1370                  *  Received S(upervisory) frame, check which frame type it is
1371                  *  only the first nibble is of interest
1372                  */
1373                 switch (control & 0x0f) {
1374                 case RR:
1375                         irlap_recv_rr_frame(self, skb, &info, command);
1376                         break;
1377                 case RNR:
1378                         irlap_recv_rnr_frame(self, skb, &info, command);
1379                         break;
1380                 case REJ:
1381                         irlap_recv_rej_frame(self, skb, &info, command);
1382                         break;
1383                 case SREJ:
1384                         irlap_recv_srej_frame(self, skb, &info, command);
1385                         break;
1386                 default:
1387                         IRDA_WARNING("%s: Unknown S-frame %02x received!\n",
1388                                 __FUNCTION__, info.control);
1389                         break;
1390                 }
1391                 goto out;
1392         }
1393         /*
1394          *  This must be a C(ontrol) frame
1395          */
1396         switch (control) {
1397         case XID_RSP:
1398                 irlap_recv_discovery_xid_rsp(self, skb, &info);
1399                 break;
1400         case XID_CMD:
1401                 irlap_recv_discovery_xid_cmd(self, skb, &info);
1402                 break;
1403         case SNRM_CMD:
1404                 irlap_recv_snrm_cmd(self, skb, &info);
1405                 break;
1406         case DM_RSP:
1407                 irlap_do_event(self, RECV_DM_RSP, skb, &info);
1408                 break;
1409         case DISC_CMD: /* And RD_RSP since they have the same value */
1410                 irlap_recv_disc_frame(self, skb, &info, command);
1411                 break;
1412         case TEST_CMD:
1413                 irlap_recv_test_frame(self, skb, &info, command);
1414                 break;
1415         case UA_RSP:
1416                 irlap_recv_ua_frame(self, skb, &info);
1417                 break;
1418         case FRMR_RSP:
1419                 irlap_recv_frmr_frame(self, skb, &info);
1420                 break;
1421         case UI_FRAME:
1422                 irlap_recv_ui_frame(self, skb, &info);
1423                 break;
1424         default:
1425                 IRDA_WARNING("%s: Unknown frame %02x received!\n",
1426                                 __FUNCTION__, info.control);
1427                 break;
1428         }
1429 out:
1430         /* Always drop our reference on the skb */
1431         dev_kfree_skb(skb);
1432         return 0;
1433 }