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