net/irda/irlap_frame.c

   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_reset_mac_header(skb);
  97         skb_reset_network_header(skb);
  98         skb_reset_transport_header(skb);
  99         skb->protocol = htons(ETH_P_IRDA);
 100         skb->priority = TC_PRIO_BESTEFFORT;
 101
 102         irlap_insert_info(self, skb);
 103
 104         dev_queue_xmit(skb);
 105 }
 106
 107 /*
 108  * Function irlap_send_snrm_cmd (void)
 109  *
 110  *    Transmits a connect SNRM command frame
 111  */
 112 void irlap_send_snrm_frame(struct irlap_cb *self, struct qos_info *qos)
 113 {
 114         struct sk_buff *tx_skb;
 115         struct snrm_frame *frame;
 116         int ret;
 117
 118         IRDA_ASSERT(self != NULL, return;);
 119         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 120
 121         /* Allocate frame */
 122         tx_skb = alloc_skb(sizeof(struct snrm_frame) +
 123                            IRLAP_NEGOCIATION_PARAMS_LEN,
 124                            GFP_ATOMIC);
 125         if (!tx_skb)
 126                 return;
 127
 128         frame = (struct snrm_frame *) skb_put(tx_skb, 2);
 129
 130         /* Insert connection address field */
 131         if (qos)
 132                 frame->caddr = CMD_FRAME | CBROADCAST;
 133         else
 134                 frame->caddr = CMD_FRAME | self->caddr;
 135
 136         /* Insert control field */
 137         frame->control = SNRM_CMD | PF_BIT;
 138
 139         /*
 140          *  If we are establishing a connection then insert QoS paramerters
 141          */
 142         if (qos) {
 143                 skb_put(tx_skb, 9); /* 25 left */
 144                 frame->saddr = cpu_to_le32(self->saddr);
 145                 frame->daddr = cpu_to_le32(self->daddr);
 146
 147                 frame->ncaddr = self->caddr;
 148
 149                 ret = irlap_insert_qos_negotiation_params(self, tx_skb);
 150                 if (ret < 0) {
 151                         dev_kfree_skb(tx_skb);
 152                         return;
 153                 }
 154         }
 155         irlap_queue_xmit(self, tx_skb);
 156 }
 157
 158 /*
 159  * Function irlap_recv_snrm_cmd (skb, info)
 160  *
 161  *    Received SNRM (Set Normal Response Mode) command frame
 162  *
 163  */
 164 static void irlap_recv_snrm_cmd(struct irlap_cb *self, struct sk_buff *skb,
 165                                 struct irlap_info *info)
 166 {
 167         struct snrm_frame *frame;
 168
 169         if (pskb_may_pull(skb,sizeof(struct snrm_frame))) {
 170                 frame = (struct snrm_frame *) skb->data;
 171
 172                 /* Copy the new connection address ignoring the C/R bit */
 173                 info->caddr = frame->ncaddr & 0xFE;
 174
 175                 /* Check if the new connection address is valid */
 176                 if ((info->caddr == 0x00) || (info->caddr == 0xfe)) {
 177                         IRDA_DEBUG(3, "%s(), invalid connection address!\n",
 178                                    __FUNCTION__);
 179                         return;
 180                 }
 181
 182                 /* Copy peer device address */
 183                 info->daddr = le32_to_cpu(frame->saddr);
 184                 info->saddr = le32_to_cpu(frame->daddr);
 185
 186                 /* Only accept if addressed directly to us */
 187                 if (info->saddr != self->saddr) {
 188                         IRDA_DEBUG(2, "%s(), not addressed to us!\n",
 189                                    __FUNCTION__);
 190                         return;
 191                 }
 192                 irlap_do_event(self, RECV_SNRM_CMD, skb, info);
 193         } else {
 194                 /* Signal that this SNRM frame does not contain and I-field */
 195                 irlap_do_event(self, RECV_SNRM_CMD, skb, NULL);
 196         }
 197 }
 198
 199 /*
 200  * Function irlap_send_ua_response_frame (qos)
 201  *
 202  *    Send UA (Unnumbered Acknowledgement) frame
 203  *
 204  */
 205 void irlap_send_ua_response_frame(struct irlap_cb *self, struct qos_info *qos)
 206 {
 207         struct sk_buff *tx_skb;
 208         struct ua_frame *frame;
 209         int ret;
 210
 211         IRDA_DEBUG(2, "%s() <%ld>\n", __FUNCTION__, jiffies);
 212
 213         IRDA_ASSERT(self != NULL, return;);
 214         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 215
 216         /* Allocate frame */
 217         tx_skb = alloc_skb(sizeof(struct ua_frame) +
 218                            IRLAP_NEGOCIATION_PARAMS_LEN,
 219                            GFP_ATOMIC);
 220         if (!tx_skb)
 221                 return;
 222
 223         frame = (struct ua_frame *) skb_put(tx_skb, 10);
 224
 225         /* Build UA response */
 226         frame->caddr = self->caddr;
 227         frame->control = UA_RSP | PF_BIT;
 228
 229         frame->saddr = cpu_to_le32(self->saddr);
 230         frame->daddr = cpu_to_le32(self->daddr);
 231
 232         /* Should we send QoS negotiation parameters? */
 233         if (qos) {
 234                 ret = irlap_insert_qos_negotiation_params(self, tx_skb);
 235                 if (ret < 0) {
 236                         dev_kfree_skb(tx_skb);
 237                         return;
 238                 }
 239         }
 240
 241         irlap_queue_xmit(self, tx_skb);
 242 }
 243
 244
 245 /*
 246  * Function irlap_send_dm_frame (void)
 247  *
 248  *    Send disconnected mode (DM) frame
 249  *
 250  */
 251 void irlap_send_dm_frame( struct irlap_cb *self)
 252 {
 253         struct sk_buff *tx_skb = NULL;
 254         struct dm_frame *frame;
 255
 256         IRDA_ASSERT(self != NULL, return;);
 257         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 258
 259         tx_skb = alloc_skb(sizeof(struct dm_frame), GFP_ATOMIC);
 260         if (!tx_skb)
 261                 return;
 262
 263         frame = (struct dm_frame *)skb_put(tx_skb, 2);
 264
 265         if (self->state == LAP_NDM)
 266                 frame->caddr = CBROADCAST;
 267         else
 268                 frame->caddr = self->caddr;
 269
 270         frame->control = DM_RSP | PF_BIT;
 271
 272         irlap_queue_xmit(self, tx_skb);
 273 }
 274
 275 /*
 276  * Function irlap_send_disc_frame (void)
 277  *
 278  *    Send disconnect (DISC) frame
 279  *
 280  */
 281 void irlap_send_disc_frame(struct irlap_cb *self)
 282 {
 283         struct sk_buff *tx_skb = NULL;
 284         struct disc_frame *frame;
 285
 286         IRDA_DEBUG(3, "%s()\n", __FUNCTION__);
 287
 288         IRDA_ASSERT(self != NULL, return;);
 289         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 290
 291         tx_skb = alloc_skb(sizeof(struct disc_frame), GFP_ATOMIC);
 292         if (!tx_skb)
 293                 return;
 294
 295         frame = (struct disc_frame *)skb_put(tx_skb, 2);
 296
 297         frame->caddr = self->caddr | CMD_FRAME;
 298         frame->control = DISC_CMD | PF_BIT;
 299
 300         irlap_queue_xmit(self, tx_skb);
 301 }
 302
 303 /*
 304  * Function irlap_send_discovery_xid_frame (S, s, command)
 305  *
 306  *    Build and transmit a XID (eXchange station IDentifier) discovery
 307  *    frame.
 308  */
 309 void irlap_send_discovery_xid_frame(struct irlap_cb *self, int S, __u8 s,
 310                                     __u8 command, discovery_t *discovery)
 311 {
 312         struct sk_buff *tx_skb = NULL;
 313         struct xid_frame *frame;
 314         __u32 bcast = BROADCAST;
 315         __u8 *info;
 316
 317         IRDA_DEBUG(4, "%s(), s=%d, S=%d, command=%d\n", __FUNCTION__,
 318                    s, S, command);
 319
 320         IRDA_ASSERT(self != NULL, return;);
 321         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 322         IRDA_ASSERT(discovery != NULL, return;);
 323
 324         tx_skb = alloc_skb(sizeof(struct xid_frame) + IRLAP_DISCOVERY_INFO_LEN,
 325                            GFP_ATOMIC);
 326         if (!tx_skb)
 327                 return;
 328
 329         skb_put(tx_skb, 14);
 330         frame = (struct xid_frame *) tx_skb->data;
 331
 332         if (command) {
 333                 frame->caddr = CBROADCAST | CMD_FRAME;
 334                 frame->control =  XID_CMD | PF_BIT;
 335         } else {
 336                 frame->caddr = CBROADCAST;
 337                 frame->control =  XID_RSP | PF_BIT;
 338         }
 339         frame->ident = XID_FORMAT;
 340
 341         frame->saddr = cpu_to_le32(self->saddr);
 342
 343         if (command)
 344                 frame->daddr = cpu_to_le32(bcast);
 345         else
 346                 frame->daddr = cpu_to_le32(discovery->data.daddr);
 347
 348         switch (S) {
 349         case 1:
 350                 frame->flags = 0x00;
 351                 break;
 352         case 6:
 353                 frame->flags = 0x01;
 354                 break;
 355         case 8:
 356                 frame->flags = 0x02;
 357                 break;
 358         case 16:
 359                 frame->flags = 0x03;
 360                 break;
 361         default:
 362                 frame->flags = 0x02;
 363                 break;
 364         }
 365
 366         frame->slotnr = s;
 367         frame->version = 0x00;
 368
 369         /*
 370          *  Provide info for final slot only in commands, and for all
 371          *  responses. Send the second byte of the hint only if the
 372          *  EXTENSION bit is set in the first byte.
 373          */
 374         if (!command || (frame->slotnr == 0xff)) {
 375                 int len;
 376
 377                 if (discovery->data.hints[0] & HINT_EXTENSION) {
 378                         info = skb_put(tx_skb, 2);
 379                         info[0] = discovery->data.hints[0];
 380                         info[1] = discovery->data.hints[1];
 381                 } else {
 382                         info = skb_put(tx_skb, 1);
 383                         info[0] = discovery->data.hints[0];
 384                 }
 385                 info = skb_put(tx_skb, 1);
 386                 info[0] = discovery->data.charset;
 387
 388                 len = IRDA_MIN(discovery->name_len, skb_tailroom(tx_skb));
 389                 info = skb_put(tx_skb, len);
 390                 memcpy(info, discovery->data.info, len);
 391         }
 392         irlap_queue_xmit(self, tx_skb);
 393 }
 394
 395 /*
 396  * Function irlap_recv_discovery_xid_rsp (skb, info)
 397  *
 398  *    Received a XID discovery response
 399  *
 400  */
 401 static void irlap_recv_discovery_xid_rsp(struct irlap_cb *self,
 402                                          struct sk_buff *skb,
 403                                          struct irlap_info *info)
 404 {
 405         struct xid_frame *xid;
 406         discovery_t *discovery = NULL;
 407         __u8 *discovery_info;
 408         char *text;
 409
 410         IRDA_DEBUG(4, "%s()\n", __FUNCTION__);
 411
 412         IRDA_ASSERT(self != NULL, return;);
 413         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 414
 415         if (!pskb_may_pull(skb, sizeof(struct xid_frame))) {
 416                 IRDA_ERROR("%s: frame too short!\n", __FUNCTION__);
 417                 return;
 418         }
 419
 420         xid = (struct xid_frame *) skb->data;
 421
 422         info->daddr = le32_to_cpu(xid->saddr);
 423         info->saddr = le32_to_cpu(xid->daddr);
 424
 425         /* Make sure frame is addressed to us */
 426         if ((info->saddr != self->saddr) && (info->saddr != BROADCAST)) {
 427                 IRDA_DEBUG(0, "%s(), frame is not addressed to us!\n",
 428                            __FUNCTION__);
 429                 return;
 430         }
 431
 432         if ((discovery = kzalloc(sizeof(discovery_t), GFP_ATOMIC)) == NULL) {
 433                 IRDA_WARNING("%s: kmalloc failed!\n", __FUNCTION__);
 434                 return;
 435         }
 436
 437         discovery->data.daddr = info->daddr;
 438         discovery->data.saddr = self->saddr;
 439         discovery->timestamp = jiffies;
 440
 441         IRDA_DEBUG(4, "%s(), daddr=%08x\n", __FUNCTION__,
 442                    discovery->data.daddr);
 443
 444         discovery_info = skb_pull(skb, sizeof(struct xid_frame));
 445
 446         /* Get info returned from peer */
 447         discovery->data.hints[0] = discovery_info[0];
 448         if (discovery_info[0] & HINT_EXTENSION) {
 449                 IRDA_DEBUG(4, "EXTENSION\n");
 450                 discovery->data.hints[1] = discovery_info[1];
 451                 discovery->data.charset = discovery_info[2];
 452                 text = (char *) &discovery_info[3];
 453         } else {
 454                 discovery->data.hints[1] = 0;
 455                 discovery->data.charset = discovery_info[1];
 456                 text = (char *) &discovery_info[2];
 457         }
 458         /*
 459          *  Terminate info string, should be safe since this is where the
 460          *  FCS bytes resides.
 461          */
 462         skb->data[skb->len] = '\0';
 463         strncpy(discovery->data.info, text, NICKNAME_MAX_LEN);
 464         discovery->name_len = strlen(discovery->data.info);
 465
 466         info->discovery = discovery;
 467
 468         irlap_do_event(self, RECV_DISCOVERY_XID_RSP, skb, info);
 469 }
 470
 471 /*
 472  * Function irlap_recv_discovery_xid_cmd (skb, info)
 473  *
 474  *    Received a XID discovery command
 475  *
 476  */
 477 static void irlap_recv_discovery_xid_cmd(struct irlap_cb *self,
 478                                          struct sk_buff *skb,
 479                                          struct irlap_info *info)
 480 {
 481         struct xid_frame *xid;
 482         discovery_t *discovery = NULL;
 483         __u8 *discovery_info;
 484         char *text;
 485
 486         if (!pskb_may_pull(skb, sizeof(struct xid_frame))) {
 487                 IRDA_ERROR("%s: frame too short!\n", __FUNCTION__);
 488                 return;
 489         }
 490
 491         xid = (struct xid_frame *) skb->data;
 492
 493         info->daddr = le32_to_cpu(xid->saddr);
 494         info->saddr = le32_to_cpu(xid->daddr);
 495
 496         /* Make sure frame is addressed to us */
 497         if ((info->saddr != self->saddr) && (info->saddr != BROADCAST)) {
 498                 IRDA_DEBUG(0, "%s(), frame is not addressed to us!\n",
 499                            __FUNCTION__);
 500                 return;
 501         }
 502
 503         switch (xid->flags & 0x03) {
 504         case 0x00:
 505                 info->S = 1;
 506                 break;
 507         case 0x01:
 508                 info->S = 6;
 509                 break;
 510         case 0x02:
 511                 info->S = 8;
 512                 break;
 513         case 0x03:
 514                 info->S = 16;
 515                 break;
 516         default:
 517                 /* Error!! */
 518                 return;
 519         }
 520         info->s = xid->slotnr;
 521
 522         discovery_info = skb_pull(skb, sizeof(struct xid_frame));
 523
 524         /*
 525          *  Check if last frame
 526          */
 527         if (info->s == 0xff) {
 528                 /* Check if things are sane at this point... */
 529                 if((discovery_info == NULL) ||
 530                    !pskb_may_pull(skb, 3)) {
 531                         IRDA_ERROR("%s: discovery frame too short!\n",
 532                                    __FUNCTION__);
 533                         return;
 534                 }
 535
 536                 /*
 537                  *  We now have some discovery info to deliver!
 538                  */
 539                 discovery = kmalloc(sizeof(discovery_t), GFP_ATOMIC);
 540                 if (!discovery) {
 541                         IRDA_WARNING("%s: unable to malloc!\n", __FUNCTION__);
 542                         return;
 543                 }
 544
 545                 discovery->data.daddr = info->daddr;
 546                 discovery->data.saddr = self->saddr;
 547                 discovery->timestamp = jiffies;
 548
 549                 discovery->data.hints[0] = discovery_info[0];
 550                 if (discovery_info[0] & HINT_EXTENSION) {
 551                         discovery->data.hints[1] = discovery_info[1];
 552                         discovery->data.charset = discovery_info[2];
 553                         text = (char *) &discovery_info[3];
 554                 } else {
 555                         discovery->data.hints[1] = 0;
 556                         discovery->data.charset = discovery_info[1];
 557                         text = (char *) &discovery_info[2];
 558                 }
 559                 /*
 560                  *  Terminate string, should be safe since this is where the
 561                  *  FCS bytes resides.
 562                  */
 563                 skb->data[skb->len] = '\0';
 564                 strncpy(discovery->data.info, text, NICKNAME_MAX_LEN);
 565                 discovery->name_len = strlen(discovery->data.info);
 566
 567                 info->discovery = discovery;
 568         } else
 569                 info->discovery = NULL;
 570
 571         irlap_do_event(self, RECV_DISCOVERY_XID_CMD, skb, info);
 572 }
 573
 574 /*
 575  * Function irlap_send_rr_frame (self, command)
 576  *
 577  *    Build and transmit RR (Receive Ready) frame. Notice that it is currently
 578  *    only possible to send RR frames with the poll bit set.
 579  */
 580 void irlap_send_rr_frame(struct irlap_cb *self, int command)
 581 {
 582         struct sk_buff *tx_skb;
 583         struct rr_frame *frame;
 584
 585         tx_skb = alloc_skb(sizeof(struct rr_frame), GFP_ATOMIC);
 586         if (!tx_skb)
 587                 return;
 588
 589         frame = (struct rr_frame *)skb_put(tx_skb, 2);
 590
 591         frame->caddr = self->caddr;
 592         frame->caddr |= (command) ? CMD_FRAME : 0;
 593
 594         frame->control = RR | PF_BIT | (self->vr << 5);
 595
 596         irlap_queue_xmit(self, tx_skb);
 597 }
 598
 599 /*
 600  * Function irlap_send_rd_frame (self)
 601  *
 602  *    Request disconnect. Used by a secondary station to request the
 603  *    disconnection of the link.
 604  */
 605 void irlap_send_rd_frame(struct irlap_cb *self)
 606 {
 607         struct sk_buff *tx_skb;
 608         struct rd_frame *frame;
 609
 610         tx_skb = alloc_skb(sizeof(struct rd_frame), GFP_ATOMIC);
 611         if (!tx_skb)
 612                 return;
 613
 614         frame = (struct rd_frame *)skb_put(tx_skb, 2);
 615
 616         frame->caddr = self->caddr;
 617         frame->caddr = RD_RSP | PF_BIT;
 618
 619         irlap_queue_xmit(self, tx_skb);
 620 }
 621
 622 /*
 623  * Function irlap_recv_rr_frame (skb, info)
 624  *
 625  *    Received RR (Receive Ready) frame from peer station, no harm in
 626  *    making it inline since its called only from one single place
 627  *    (irlap_driver_rcv).
 628  */
 629 static inline void irlap_recv_rr_frame(struct irlap_cb *self,
 630                                        struct sk_buff *skb,
 631                                        struct irlap_info *info, int command)
 632 {
 633         info->nr = skb->data[1] >> 5;
 634
 635         /* Check if this is a command or a response frame */
 636         if (command)
 637                 irlap_do_event(self, RECV_RR_CMD, skb, info);
 638         else
 639                 irlap_do_event(self, RECV_RR_RSP, skb, info);
 640 }
 641
 642 /*
 643  * Function irlap_recv_rnr_frame (self, skb, info)
 644  *
 645  *    Received RNR (Receive Not Ready) frame from peer station
 646  *
 647  */
 648 static void irlap_recv_rnr_frame(struct irlap_cb *self, struct sk_buff *skb,
 649                                  struct irlap_info *info, int command)
 650 {
 651         info->nr = skb->data[1] >> 5;
 652
 653         IRDA_DEBUG(4, "%s(), nr=%d, %ld\n", __FUNCTION__, info->nr, jiffies);
 654
 655         if (command)
 656                 irlap_do_event(self, RECV_RNR_CMD, skb, info);
 657         else
 658                 irlap_do_event(self, RECV_RNR_RSP, skb, info);
 659 }
 660
 661 static void irlap_recv_rej_frame(struct irlap_cb *self, struct sk_buff *skb,
 662                                  struct irlap_info *info, int command)
 663 {
 664         IRDA_DEBUG(0, "%s()\n", __FUNCTION__);
 665
 666         info->nr = skb->data[1] >> 5;
 667
 668         /* Check if this is a command or a response frame */
 669         if (command)
 670                 irlap_do_event(self, RECV_REJ_CMD, skb, info);
 671         else
 672                 irlap_do_event(self, RECV_REJ_RSP, skb, info);
 673 }
 674
 675 static void irlap_recv_srej_frame(struct irlap_cb *self, struct sk_buff *skb,
 676                                   struct irlap_info *info, int command)
 677 {
 678         IRDA_DEBUG(0, "%s()\n", __FUNCTION__);
 679
 680         info->nr = skb->data[1] >> 5;
 681
 682         /* Check if this is a command or a response frame */
 683         if (command)
 684                 irlap_do_event(self, RECV_SREJ_CMD, skb, info);
 685         else
 686                 irlap_do_event(self, RECV_SREJ_RSP, skb, info);
 687 }
 688
 689 static void irlap_recv_disc_frame(struct irlap_cb *self, struct sk_buff *skb,
 690                                   struct irlap_info *info, int command)
 691 {
 692         IRDA_DEBUG(2, "%s()\n", __FUNCTION__);
 693
 694         /* Check if this is a command or a response frame */
 695         if (command)
 696                 irlap_do_event(self, RECV_DISC_CMD, skb, info);
 697         else
 698                 irlap_do_event(self, RECV_RD_RSP, skb, info);
 699 }
 700
 701 /*
 702  * Function irlap_recv_ua_frame (skb, frame)
 703  *
 704  *    Received UA (Unnumbered Acknowledgement) frame
 705  *
 706  */
 707 static inline void irlap_recv_ua_frame(struct irlap_cb *self,
 708                                        struct sk_buff *skb,
 709                                        struct irlap_info *info)
 710 {
 711         irlap_do_event(self, RECV_UA_RSP, skb, info);
 712 }
 713
 714 /*
 715  * Function irlap_send_data_primary(self, skb)
 716  *
 717  *    Send I-frames as the primary station but without the poll bit set
 718  *
 719  */
 720 void irlap_send_data_primary(struct irlap_cb *self, struct sk_buff *skb)
 721 {
 722         struct sk_buff *tx_skb;
 723
 724         if (skb->data[1] == I_FRAME) {
 725
 726                 /*
 727                  *  Insert frame sequence number (Vs) in control field before
 728                  *  inserting into transmit window queue.
 729                  */
 730                 skb->data[1] = I_FRAME | (self->vs << 1);
 731
 732                 /*
 733                  *  Insert frame in store, in case of retransmissions
 734                  *  Increase skb reference count, see irlap_do_event()
 735                  */
 736                 skb_get(skb);
 737                 skb_queue_tail(&self->wx_list, skb);
 738
 739                 /* Copy buffer */
 740                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 741                 if (tx_skb == NULL) {
 742                         return;
 743                 }
 744
 745                 self->vs = (self->vs + 1) % 8;
 746                 self->ack_required = FALSE;
 747                 self->window -= 1;
 748
 749                 irlap_send_i_frame( self, tx_skb, CMD_FRAME);
 750         } else {
 751                 IRDA_DEBUG(4, "%s(), sending unreliable frame\n", __FUNCTION__);
 752                 irlap_send_ui_frame(self, skb_get(skb), self->caddr, CMD_FRAME);
 753                 self->window -= 1;
 754         }
 755 }
 756 /*
 757  * Function irlap_send_data_primary_poll (self, skb)
 758  *
 759  *    Send I(nformation) frame as primary with poll bit set
 760  */
 761 void irlap_send_data_primary_poll(struct irlap_cb *self, struct sk_buff *skb)
 762 {
 763         struct sk_buff *tx_skb;
 764         int transmission_time;
 765
 766         /* Stop P timer */
 767         del_timer(&self->poll_timer);
 768
 769         /* Is this reliable or unreliable data? */
 770         if (skb->data[1] == I_FRAME) {
 771
 772                 /*
 773                  *  Insert frame sequence number (Vs) in control field before
 774                  *  inserting into transmit window queue.
 775                  */
 776                 skb->data[1] = I_FRAME | (self->vs << 1);
 777
 778                 /*
 779                  *  Insert frame in store, in case of retransmissions
 780                  *  Increase skb reference count, see irlap_do_event()
 781                  */
 782                 skb_get(skb);
 783                 skb_queue_tail(&self->wx_list, skb);
 784
 785                 /* Copy buffer */
 786                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 787                 if (tx_skb == NULL) {
 788                         return;
 789                 }
 790
 791                 /*
 792                  *  Set poll bit if necessary. We do this to the copied
 793                  *  skb, since retransmitted need to set or clear the poll
 794                  *  bit depending on when they are sent.
 795                  */
 796                 tx_skb->data[1] |= PF_BIT;
 797
 798                 self->vs = (self->vs + 1) % 8;
 799                 self->ack_required = FALSE;
 800
 801                 irlap_send_i_frame(self, tx_skb, CMD_FRAME);
 802         } else {
 803                 IRDA_DEBUG(4, "%s(), sending unreliable frame\n", __FUNCTION__);
 804
 805                 if (self->ack_required) {
 806                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, CMD_FRAME);
 807                         irlap_send_rr_frame(self, CMD_FRAME);
 808                         self->ack_required = FALSE;
 809                 } else {
 810                         skb->data[1] |= PF_BIT;
 811                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, CMD_FRAME);
 812                 }
 813         }
 814
 815         /* How much time we took for transmission of all frames.
 816          * We don't know, so let assume we used the full window. Jean II */
 817         transmission_time = self->final_timeout;
 818
 819         /* Reset parameter so that we can fill next window */
 820         self->window = self->window_size;
 821
 822 #ifdef CONFIG_IRDA_DYNAMIC_WINDOW
 823         /* Remove what we have not used. Just do a prorata of the
 824          * bytes left in window to window capacity.
 825          * See max_line_capacities[][] in qos.c for details. Jean II */
 826         transmission_time -= (self->final_timeout * self->bytes_left
 827                               / self->line_capacity);
 828         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);
 829
 830         /* We are allowed to transmit a maximum number of bytes again. */
 831         self->bytes_left = self->line_capacity;
 832 #endif /* CONFIG_IRDA_DYNAMIC_WINDOW */
 833
 834         /*
 835          * The network layer has a intermediate buffer between IrLAP
 836          * and the IrDA driver which can contain 8 frames. So, even
 837          * though IrLAP is currently sending the *last* frame of the
 838          * tx-window, the driver most likely has only just started
 839          * sending the *first* frame of the same tx-window.
 840          * I.e. we are always at the very begining of or Tx window.
 841          * Now, we are supposed to set the final timer from the end
 842          * of our tx-window to let the other peer reply. So, we need
 843          * to add extra time to compensate for the fact that we
 844          * are really at the start of tx-window, otherwise the final timer
 845          * might expire before he can answer...
 846          * Jean II
 847          */
 848         irlap_start_final_timer(self, self->final_timeout + transmission_time);
 849
 850         /*
 851          * The clever amongst you might ask why we do this adjustement
 852          * only here, and not in all the other cases in irlap_event.c.
 853          * In all those other case, we only send a very short management
 854          * frame (few bytes), so the adjustement would be lost in the
 855          * noise...
 856          * The exception of course is irlap_resend_rejected_frame().
 857          * Jean II */
 858 }
 859
 860 /*
 861  * Function irlap_send_data_secondary_final (self, skb)
 862  *
 863  *    Send I(nformation) frame as secondary with final bit set
 864  *
 865  */
 866 void irlap_send_data_secondary_final(struct irlap_cb *self,
 867                                      struct sk_buff *skb)
 868 {
 869         struct sk_buff *tx_skb = NULL;
 870
 871         IRDA_ASSERT(self != NULL, return;);
 872         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 873         IRDA_ASSERT(skb != NULL, return;);
 874
 875         /* Is this reliable or unreliable data? */
 876         if (skb->data[1] == I_FRAME) {
 877
 878                 /*
 879                  *  Insert frame sequence number (Vs) in control field before
 880                  *  inserting into transmit window queue.
 881                  */
 882                 skb->data[1] = I_FRAME | (self->vs << 1);
 883
 884                 /*
 885                  *  Insert frame in store, in case of retransmissions
 886                  *  Increase skb reference count, see irlap_do_event()
 887                  */
 888                 skb_get(skb);
 889                 skb_queue_tail(&self->wx_list, skb);
 890
 891                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 892                 if (tx_skb == NULL) {
 893                         return;
 894                 }
 895
 896                 tx_skb->data[1] |= PF_BIT;
 897
 898                 self->vs = (self->vs + 1) % 8;
 899                 self->ack_required = FALSE;
 900
 901                 irlap_send_i_frame(self, tx_skb, RSP_FRAME);
 902         } else {
 903                 if (self->ack_required) {
 904                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, RSP_FRAME);
 905                         irlap_send_rr_frame(self, RSP_FRAME);
 906                         self->ack_required = FALSE;
 907                 } else {
 908                         skb->data[1] |= PF_BIT;
 909                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, RSP_FRAME);
 910                 }
 911         }
 912
 913         self->window = self->window_size;
 914 #ifdef CONFIG_IRDA_DYNAMIC_WINDOW
 915         /* We are allowed to transmit a maximum number of bytes again. */
 916         self->bytes_left = self->line_capacity;
 917 #endif /* CONFIG_IRDA_DYNAMIC_WINDOW */
 918
 919         irlap_start_wd_timer(self, self->wd_timeout);
 920 }
 921
 922 /*
 923  * Function irlap_send_data_secondary (self, skb)
 924  *
 925  *    Send I(nformation) frame as secondary without final bit set
 926  *
 927  */
 928 void irlap_send_data_secondary(struct irlap_cb *self, struct sk_buff *skb)
 929 {
 930         struct sk_buff *tx_skb = NULL;
 931
 932         /* Is this reliable or unreliable data? */
 933         if (skb->data[1] == I_FRAME) {
 934
 935                 /*
 936                  *  Insert frame sequence number (Vs) in control field before
 937                  *  inserting into transmit window queue.
 938                  */
 939                 skb->data[1] = I_FRAME | (self->vs << 1);
 940
 941                 /*
 942                  *  Insert frame in store, in case of retransmissions
 943                  *  Increase skb reference count, see irlap_do_event()
 944                  */
 945                 skb_get(skb);
 946                 skb_queue_tail(&self->wx_list, skb);
 947
 948                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 949                 if (tx_skb == NULL) {
 950                         return;
 951                 }
 952
 953                 self->vs = (self->vs + 1) % 8;
 954                 self->ack_required = FALSE;
 955                 self->window -= 1;
 956
 957                 irlap_send_i_frame(self, tx_skb, RSP_FRAME);
 958         } else {
 959                 irlap_send_ui_frame(self, skb_get(skb), self->caddr, RSP_FRAME);
 960                 self->window -= 1;
 961         }
 962 }
 963
 964 /*
 965  * Function irlap_resend_rejected_frames (nr)
 966  *
 967  *    Resend frames which has not been acknowledged. Should be safe to
 968  *    traverse the list without locking it since this function will only be
 969  *    called from interrupt context (BH)
 970  */
 971 void irlap_resend_rejected_frames(struct irlap_cb *self, int command)
 972 {
 973         struct sk_buff *tx_skb;
 974         struct sk_buff *skb;
 975         int count;
 976
 977         IRDA_ASSERT(self != NULL, return;);
 978         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 979
 980         /* Initialize variables */
 981         count = skb_queue_len(&self->wx_list);
 982
 983         /*  Resend unacknowledged frame(s) */
 984         skb = skb_peek(&self->wx_list);
 985         while (skb != NULL) {
 986                 irlap_wait_min_turn_around(self, &self->qos_tx);
 987
 988                 /* We copy the skb to be retransmitted since we will have to
 989                  * modify it. Cloning will confuse packet sniffers
 990                  */
 991                 /* tx_skb = skb_clone( skb, GFP_ATOMIC); */
 992                 tx_skb = skb_copy(skb, GFP_ATOMIC);
 993                 if (!tx_skb) {
 994                         IRDA_DEBUG(0, "%s(), unable to copy\n", __FUNCTION__);
 995                         return;
 996                 }
 997
 998                 /* Clear old Nr field + poll bit */
 999                 tx_skb->data[1] &= 0x0f;
1000
1001                 /*
1002                  *  Set poll bit on the last frame retransmitted
1003                  */
1004                 if (count-- == 1)
1005                         tx_skb->data[1] |= PF_BIT; /* Set p/f bit */
1006                 else
1007                         tx_skb->data[1] &= ~PF_BIT; /* Clear p/f bit */
1008
1009                 irlap_send_i_frame(self, tx_skb, command);
1010
1011                 /*
1012                  *  If our skb is the last buffer in the list, then
1013                  *  we are finished, if not, move to the next sk-buffer
1014                  */
1015                 if (skb == skb_peek_tail(&self->wx_list))
1016                         skb = NULL;
1017                 else
1018                         skb = skb->next;
1019         }
1020 #if 0 /* Not yet */
1021         /*
1022          *  We can now fill the window with additional data frames
1023          */
1024         while (!skb_queue_empty(&self->txq)) {
1025
1026                 IRDA_DEBUG(0, "%s(), sending additional frames!\n", __FUNCTION__);
1027                 if (self->window > 0) {
1028                         skb = skb_dequeue( &self->txq);
1029                         IRDA_ASSERT(skb != NULL, return;);
1030
1031                         /*
1032                          *  If send window > 1 then send frame with pf
1033                          *  bit cleared
1034                          */
1035                         if ((self->window > 1) &&
1036                             !skb_queue_empty(&self->txq)) {
1037                                 irlap_send_data_primary(self, skb);
1038                         } else {
1039                                 irlap_send_data_primary_poll(self, skb);
1040                         }
1041                         kfree_skb(skb);
1042                 }
1043         }
1044 #endif
1045 }
1046
1047 void irlap_resend_rejected_frame(struct irlap_cb *self, int command)
1048 {
1049         struct sk_buff *tx_skb;
1050         struct sk_buff *skb;
1051
1052         IRDA_ASSERT(self != NULL, return;);
1053         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
1054
1055         /*  Resend unacknowledged frame(s) */
1056         skb = skb_peek(&self->wx_list);
1057         if (skb != NULL) {
1058                 irlap_wait_min_turn_around(self, &self->qos_tx);
1059
1060                 /* We copy the skb to be retransmitted since we will have to
1061                  * modify it. Cloning will confuse packet sniffers
1062                  */
1063                 /* tx_skb = skb_clone( skb, GFP_ATOMIC); */
1064                 tx_skb = skb_copy(skb, GFP_ATOMIC);
1065                 if (!tx_skb) {
1066                         IRDA_DEBUG(0, "%s(), unable to copy\n", __FUNCTION__);
1067                         return;
1068                 }
1069
1070                 /* Clear old Nr field + poll bit */
1071                 tx_skb->data[1] &= 0x0f;
1072
1073                 /*  Set poll/final bit */
1074                 tx_skb->data[1] |= PF_BIT; /* Set p/f bit */
1075
1076                 irlap_send_i_frame(self, tx_skb, command);
1077         }
1078 }
1079
1080 /*
1081  * Function irlap_send_ui_frame (self, skb, command)
1082  *
1083  *    Contruct and transmit an Unnumbered Information (UI) frame
1084  *
1085  */
1086 void irlap_send_ui_frame(struct irlap_cb *self, struct sk_buff *skb,
1087                          __u8 caddr, int command)
1088 {
1089         IRDA_DEBUG(4, "%s()\n", __FUNCTION__);
1090
1091         IRDA_ASSERT(self != NULL, return;);
1092         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
1093         IRDA_ASSERT(skb != NULL, return;);
1094
1095         /* Insert connection address */
1096         skb->data[0] = caddr | ((command) ? CMD_FRAME : 0);
1097
1098         irlap_queue_xmit(self, skb);
1099 }
1100
1101 /*
1102  * Function irlap_send_i_frame (skb)
1103  *
1104  *    Contruct and transmit Information (I) frame
1105  */
1106 static void irlap_send_i_frame(struct irlap_cb *self, struct sk_buff *skb,
1107                                int command)
1108 {
1109         /* Insert connection address */
1110         skb->data[0] = self->caddr;
1111         skb->data[0] |= (command) ? CMD_FRAME : 0;
1112
1113         /* Insert next to receive (Vr) */
1114         skb->data[1] |= (self->vr << 5);  /* insert nr */
1115
1116         irlap_queue_xmit(self, skb);
1117 }
1118
1119 /*
1120  * Function irlap_recv_i_frame (skb, frame)
1121  *
1122  *    Receive and parse an I (Information) frame, no harm in making it inline
1123  *    since it's called only from one single place (irlap_driver_rcv).
1124  */
1125 static inline void irlap_recv_i_frame(struct irlap_cb *self,
1126                                       struct sk_buff *skb,
1127                                       struct irlap_info *info, int command)
1128 {
1129         info->nr = skb->data[1] >> 5;          /* Next to receive */
1130         info->pf = skb->data[1] & PF_BIT;      /* Final bit */
1131         info->ns = (skb->data[1] >> 1) & 0x07; /* Next to send */
1132
1133         /* Check if this is a command or a response frame */
1134         if (command)
1135                 irlap_do_event(self, RECV_I_CMD, skb, info);
1136         else
1137                 irlap_do_event(self, RECV_I_RSP, skb, info);
1138 }
1139
1140 /*
1141  * Function irlap_recv_ui_frame (self, skb, info)
1142  *
1143  *    Receive and parse an Unnumbered Information (UI) frame
1144  *
1145  */
1146 static void irlap_recv_ui_frame(struct irlap_cb *self, struct sk_buff *skb,
1147                                 struct irlap_info *info)
1148 {
1149         IRDA_DEBUG( 4, "%s()\n", __FUNCTION__);
1150
1151         info->pf = skb->data[1] & PF_BIT;      /* Final bit */
1152
1153         irlap_do_event(self, RECV_UI_FRAME, skb, info);
1154 }
1155
1156 /*
1157  * Function irlap_recv_frmr_frame (skb, frame)
1158  *
1159  *    Received Frame Reject response.
1160  *
1161  */
1162 static void irlap_recv_frmr_frame(struct irlap_cb *self, struct sk_buff *skb,
1163                                   struct irlap_info *info)
1164 {
1165         __u8 *frame;
1166         int w, x, y, z;
1167
1168         IRDA_DEBUG(0, "%s()\n", __FUNCTION__);
1169
1170         IRDA_ASSERT(self != NULL, return;);
1171         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
1172         IRDA_ASSERT(skb != NULL, return;);
1173         IRDA_ASSERT(info != NULL, return;);
1174
1175         if (!pskb_may_pull(skb, 4)) {
1176                 IRDA_ERROR("%s: frame too short!\n", __FUNCTION__);
1177                 return;
1178         }
1179
1180         frame = skb->data;
1181
1182         info->nr = frame[2] >> 5;          /* Next to receive */
1183         info->pf = frame[2] & PF_BIT;      /* Final bit */
1184         info->ns = (frame[2] >> 1) & 0x07; /* Next to send */
1185
1186         w = frame[3] & 0x01;
1187         x = frame[3] & 0x02;
1188         y = frame[3] & 0x04;
1189         z = frame[3] & 0x08;
1190
1191         if (w) {
1192                 IRDA_DEBUG(0, "Rejected control field is undefined or not "
1193                       "implemented.\n");
1194         }
1195         if (x) {
1196                 IRDA_DEBUG(0, "Rejected control field was invalid because it "
1197                       "contained a non permitted I field.\n");
1198         }
1199         if (y) {
1200                 IRDA_DEBUG(0, "Received I field exceeded the maximum negotiated "
1201                       "for the existing connection or exceeded the maximum "
1202                       "this station supports if no connection exists.\n");
1203         }
1204         if (z) {
1205                 IRDA_DEBUG(0, "Rejected control field control field contained an "
1206                       "invalid Nr count.\n");
1207         }
1208         irlap_do_event(self, RECV_FRMR_RSP, skb, info);
1209 }
1210
1211 /*
1212  * Function irlap_send_test_frame (self, daddr)
1213  *
1214  *    Send a test frame response
1215  *
1216  */
1217 void irlap_send_test_frame(struct irlap_cb *self, __u8 caddr, __u32 daddr,
1218                            struct sk_buff *cmd)
1219 {
1220         struct sk_buff *tx_skb;
1221         struct test_frame *frame;
1222         __u8 *info;
1223
1224         tx_skb = alloc_skb(cmd->len + sizeof(struct test_frame), GFP_ATOMIC);
1225         if (!tx_skb)
1226                 return;
1227
1228         /* Broadcast frames must include saddr and daddr fields */
1229         if (caddr == CBROADCAST) {
1230                 frame = (struct test_frame *)
1231                         skb_put(tx_skb, sizeof(struct test_frame));
1232
1233                 /* Insert the swapped addresses */
1234                 frame->saddr = cpu_to_le32(self->saddr);
1235                 frame->daddr = cpu_to_le32(daddr);
1236         } else
1237                 frame = (struct test_frame *) skb_put(tx_skb, LAP_ADDR_HEADER + LAP_CTRL_HEADER);
1238
1239         frame->caddr = caddr;
1240         frame->control = TEST_RSP | PF_BIT;
1241
1242         /* Copy info */
1243         info = skb_put(tx_skb, cmd->len);
1244         memcpy(info, cmd->data, cmd->len);
1245
1246         /* Return to sender */
1247         irlap_wait_min_turn_around(self, &self->qos_tx);
1248         irlap_queue_xmit(self, tx_skb);
1249 }
1250
1251 /*
1252  * Function irlap_recv_test_frame (self, skb)
1253  *
1254  *    Receive a test frame
1255  *
1256  */
1257 static void irlap_recv_test_frame(struct irlap_cb *self, struct sk_buff *skb,
1258                                   struct irlap_info *info, int command)
1259 {
1260         struct test_frame *frame;
1261
1262         IRDA_DEBUG(2, "%s()\n", __FUNCTION__);
1263
1264         if (!pskb_may_pull(skb, sizeof(*frame))) {
1265                 IRDA_ERROR("%s: frame too short!\n", __FUNCTION__);
1266                 return;
1267         }
1268         frame = (struct test_frame *) skb->data;
1269
1270         /* Broadcast frames must carry saddr and daddr fields */
1271         if (info->caddr == CBROADCAST) {
1272                 if (skb->len < sizeof(struct test_frame)) {
1273                         IRDA_DEBUG(0, "%s() test frame too short!\n",
1274                                    __FUNCTION__);
1275                         return;
1276                 }
1277
1278                 /* Read and swap addresses */
1279                 info->daddr = le32_to_cpu(frame->saddr);
1280                 info->saddr = le32_to_cpu(frame->daddr);
1281
1282                 /* Make sure frame is addressed to us */
1283                 if ((info->saddr != self->saddr) &&
1284                     (info->saddr != BROADCAST)) {
1285                         return;
1286                 }
1287         }
1288
1289         if (command)
1290                 irlap_do_event(self, RECV_TEST_CMD, skb, info);
1291         else
1292                 irlap_do_event(self, RECV_TEST_RSP, skb, info);
1293 }
1294
1295 /*
1296  * Function irlap_driver_rcv (skb, netdev, ptype)
1297  *
1298  *    Called when a frame is received. Dispatches the right receive function
1299  *    for processing of the frame.
1300  *
1301  * Note on skb management :
1302  * After calling the higher layers of the IrDA stack, we always
1303  * kfree() the skb, which drop the reference count (and potentially
1304  * destroy it).
1305  * If a higher layer of the stack want to keep the skb around (to put
1306  * in a queue or pass it to the higher layer), it will need to use
1307  * skb_get() to keep a reference on it. This is usually done at the
1308  * LMP level in irlmp.c.
1309  * Jean II
1310  */
1311 int irlap_driver_rcv(struct sk_buff *skb, struct net_device *dev,
1312                      struct packet_type *ptype, struct net_device *orig_dev)
1313 {
1314         struct irlap_info info;
1315         struct irlap_cb *self;
1316         int command;
1317         __u8 control;
1318
1319         /* FIXME: should we get our own field? */
1320         self = (struct irlap_cb *) dev->atalk_ptr;
1321
1322         /* If the net device is down, then IrLAP is gone! */
1323         if (!self || self->magic != LAP_MAGIC) {
1324                 dev_kfree_skb(skb);
1325                 return -1;
1326         }
1327
1328         /* We are no longer an "old" protocol, so we need to handle
1329          * share and non linear skbs. This should never happen, so
1330          * we don't need to be clever about it. Jean II */
1331         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
1332                 IRDA_ERROR("%s: can't clone shared skb!\n", __FUNCTION__);
1333                 dev_kfree_skb(skb);
1334                 return -1;
1335         }
1336
1337         /* Check if frame is large enough for parsing */
1338         if (!pskb_may_pull(skb, 2)) {
1339                 IRDA_ERROR("%s: frame too short!\n", __FUNCTION__);
1340                 dev_kfree_skb(skb);
1341                 return -1;
1342         }
1343
1344         command    = skb->data[0] & CMD_FRAME;
1345         info.caddr = skb->data[0] & CBROADCAST;
1346
1347         info.pf      = skb->data[1] &  PF_BIT;
1348         info.control = skb->data[1] & ~PF_BIT; /* Mask away poll/final bit */
1349
1350         control = info.control;
1351
1352         /*  First we check if this frame has a valid connection address */
1353         if ((info.caddr != self->caddr) && (info.caddr != CBROADCAST)) {
1354                 IRDA_DEBUG(0, "%s(), wrong connection address!\n",
1355                            __FUNCTION__);
1356                 goto out;
1357         }
1358         /*
1359          *  Optimize for the common case and check if the frame is an
1360          *  I(nformation) frame. Only I-frames have bit 0 set to 0
1361          */
1362         if (~control & 0x01) {
1363                 irlap_recv_i_frame(self, skb, &info, command);
1364                 goto out;
1365         }
1366         /*
1367          *  We now check is the frame is an S(upervisory) frame. Only
1368          *  S-frames have bit 0 set to 1 and bit 1 set to 0
1369          */
1370         if (~control & 0x02) {
1371                 /*
1372                  *  Received S(upervisory) frame, check which frame type it is
1373                  *  only the first nibble is of interest
1374                  */
1375                 switch (control & 0x0f) {
1376                 case RR:
1377                         irlap_recv_rr_frame(self, skb, &info, command);
1378                         break;
1379                 case RNR:
1380                         irlap_recv_rnr_frame(self, skb, &info, command);
1381                         break;
1382                 case REJ:
1383                         irlap_recv_rej_frame(self, skb, &info, command);
1384                         break;
1385                 case SREJ:
1386                         irlap_recv_srej_frame(self, skb, &info, command);
1387                         break;
1388                 default:
1389                         IRDA_WARNING("%s: Unknown S-frame %02x received!\n",
1390                                 __FUNCTION__, info.control);
1391                         break;
1392                 }
1393                 goto out;
1394         }
1395         /*
1396          *  This must be a C(ontrol) frame
1397          */
1398         switch (control) {
1399         case XID_RSP:
1400                 irlap_recv_discovery_xid_rsp(self, skb, &info);
1401                 break;
1402         case XID_CMD:
1403                 irlap_recv_discovery_xid_cmd(self, skb, &info);
1404                 break;
1405         case SNRM_CMD:
1406                 irlap_recv_snrm_cmd(self, skb, &info);
1407                 break;
1408         case DM_RSP:
1409                 irlap_do_event(self, RECV_DM_RSP, skb, &info);
1410                 break;
1411         case DISC_CMD: /* And RD_RSP since they have the same value */
1412                 irlap_recv_disc_frame(self, skb, &info, command);
1413                 break;
1414         case TEST_CMD:
1415                 irlap_recv_test_frame(self, skb, &info, command);
1416                 break;
1417         case UA_RSP:
1418                 irlap_recv_ua_frame(self, skb, &info);
1419                 break;
1420         case FRMR_RSP:
1421                 irlap_recv_frmr_frame(self, skb, &info);
1422                 break;
1423         case UI_FRAME:
1424                 irlap_recv_ui_frame(self, skb, &info);
1425                 break;
1426         default:
1427                 IRDA_WARNING("%s: Unknown frame %02x received!\n",
1428                                 __FUNCTION__, info.control);
1429                 break;
1430         }
1431 out:
1432         /* Always drop our reference on the skb */
1433         dev_kfree_skb(skb);
1434         return 0;
1435 }