kernel/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 = (struct snrm_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 = (struct ua_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 = (struct dm_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 = (struct disc_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                 info = skb_put(tx_skb, len);
 396                 memcpy(info, discovery->data.info, len);
 397         }
 398         irlap_queue_xmit(self, tx_skb);
 399 }
 400
 401 /*
 402  * Function irlap_recv_discovery_xid_rsp (skb, info)
 403  *
 404  *    Received a XID discovery response
 405  *
 406  */
 407 static void irlap_recv_discovery_xid_rsp(struct irlap_cb *self,
 408                                          struct sk_buff *skb,
 409                                          struct irlap_info *info)
 410 {
 411         struct xid_frame *xid;
 412         discovery_t *discovery = NULL;
 413         __u8 *discovery_info;
 414         char *text;
 415
 416         IRDA_ASSERT(self != NULL, return;);
 417         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 418
 419         if (!pskb_may_pull(skb, sizeof(struct xid_frame))) {
 420                 net_err_ratelimited("%s: frame too short!\n", __func__);
 421                 return;
 422         }
 423
 424         xid = (struct xid_frame *) skb->data;
 425
 426         info->daddr = le32_to_cpu(xid->saddr);
 427         info->saddr = le32_to_cpu(xid->daddr);
 428
 429         /* Make sure frame is addressed to us */
 430         if ((info->saddr != self->saddr) && (info->saddr != BROADCAST)) {
 431                 pr_debug("%s(), frame is not addressed to us!\n",
 432                          __func__);
 433                 return;
 434         }
 435
 436         if ((discovery = kzalloc(sizeof(discovery_t), GFP_ATOMIC)) == NULL) {
 437                 net_warn_ratelimited("%s: kmalloc failed!\n", __func__);
 438                 return;
 439         }
 440
 441         discovery->data.daddr = info->daddr;
 442         discovery->data.saddr = self->saddr;
 443         discovery->timestamp = jiffies;
 444
 445         pr_debug("%s(), daddr=%08x\n", __func__,
 446                  discovery->data.daddr);
 447
 448         discovery_info = skb_pull(skb, sizeof(struct xid_frame));
 449
 450         /* Get info returned from peer */
 451         discovery->data.hints[0] = discovery_info[0];
 452         if (discovery_info[0] & HINT_EXTENSION) {
 453                 pr_debug("EXTENSION\n");
 454                 discovery->data.hints[1] = discovery_info[1];
 455                 discovery->data.charset = discovery_info[2];
 456                 text = (char *) &discovery_info[3];
 457         } else {
 458                 discovery->data.hints[1] = 0;
 459                 discovery->data.charset = discovery_info[1];
 460                 text = (char *) &discovery_info[2];
 461         }
 462         /*
 463          *  Terminate info string, should be safe since this is where the
 464          *  FCS bytes resides.
 465          */
 466         skb->data[skb->len] = '\0';
 467         strncpy(discovery->data.info, text, NICKNAME_MAX_LEN);
 468         discovery->name_len = strlen(discovery->data.info);
 469
 470         info->discovery = discovery;
 471
 472         irlap_do_event(self, RECV_DISCOVERY_XID_RSP, skb, info);
 473 }
 474
 475 /*
 476  * Function irlap_recv_discovery_xid_cmd (skb, info)
 477  *
 478  *    Received a XID discovery command
 479  *
 480  */
 481 static void irlap_recv_discovery_xid_cmd(struct irlap_cb *self,
 482                                          struct sk_buff *skb,
 483                                          struct irlap_info *info)
 484 {
 485         struct xid_frame *xid;
 486         discovery_t *discovery = NULL;
 487         __u8 *discovery_info;
 488         char *text;
 489
 490         if (!pskb_may_pull(skb, sizeof(struct xid_frame))) {
 491                 net_err_ratelimited("%s: frame too short!\n", __func__);
 492                 return;
 493         }
 494
 495         xid = (struct xid_frame *) skb->data;
 496
 497         info->daddr = le32_to_cpu(xid->saddr);
 498         info->saddr = le32_to_cpu(xid->daddr);
 499
 500         /* Make sure frame is addressed to us */
 501         if ((info->saddr != self->saddr) && (info->saddr != BROADCAST)) {
 502                 pr_debug("%s(), frame is not addressed to us!\n",
 503                          __func__);
 504                 return;
 505         }
 506
 507         switch (xid->flags & 0x03) {
 508         case 0x00:
 509                 info->S = 1;
 510                 break;
 511         case 0x01:
 512                 info->S = 6;
 513                 break;
 514         case 0x02:
 515                 info->S = 8;
 516                 break;
 517         case 0x03:
 518                 info->S = 16;
 519                 break;
 520         default:
 521                 /* Error!! */
 522                 return;
 523         }
 524         info->s = xid->slotnr;
 525
 526         discovery_info = skb_pull(skb, sizeof(struct xid_frame));
 527
 528         /*
 529          *  Check if last frame
 530          */
 531         if (info->s == 0xff) {
 532                 /* Check if things are sane at this point... */
 533                 if((discovery_info == NULL) ||
 534                    !pskb_may_pull(skb, 3)) {
 535                         net_err_ratelimited("%s: discovery frame too short!\n",
 536                                             __func__);
 537                         return;
 538                 }
 539
 540                 /*
 541                  *  We now have some discovery info to deliver!
 542                  */
 543                 discovery = kzalloc(sizeof(discovery_t), GFP_ATOMIC);
 544                 if (!discovery)
 545                         return;
 546
 547                 discovery->data.daddr = info->daddr;
 548                 discovery->data.saddr = self->saddr;
 549                 discovery->timestamp = jiffies;
 550
 551                 discovery->data.hints[0] = discovery_info[0];
 552                 if (discovery_info[0] & HINT_EXTENSION) {
 553                         discovery->data.hints[1] = discovery_info[1];
 554                         discovery->data.charset = discovery_info[2];
 555                         text = (char *) &discovery_info[3];
 556                 } else {
 557                         discovery->data.hints[1] = 0;
 558                         discovery->data.charset = discovery_info[1];
 559                         text = (char *) &discovery_info[2];
 560                 }
 561                 /*
 562                  *  Terminate string, should be safe since this is where the
 563                  *  FCS bytes resides.
 564                  */
 565                 skb->data[skb->len] = '\0';
 566                 strncpy(discovery->data.info, text, NICKNAME_MAX_LEN);
 567                 discovery->name_len = strlen(discovery->data.info);
 568
 569                 info->discovery = discovery;
 570         } else
 571                 info->discovery = NULL;
 572
 573         irlap_do_event(self, RECV_DISCOVERY_XID_CMD, skb, info);
 574 }
 575
 576 /*
 577  * Function irlap_send_rr_frame (self, command)
 578  *
 579  *    Build and transmit RR (Receive Ready) frame. Notice that it is currently
 580  *    only possible to send RR frames with the poll bit set.
 581  */
 582 void irlap_send_rr_frame(struct irlap_cb *self, int command)
 583 {
 584         struct sk_buff *tx_skb;
 585         struct rr_frame *frame;
 586
 587         tx_skb = alloc_skb(sizeof(struct rr_frame), GFP_ATOMIC);
 588         if (!tx_skb)
 589                 return;
 590
 591         frame = (struct rr_frame *)skb_put(tx_skb, 2);
 592
 593         frame->caddr = self->caddr;
 594         frame->caddr |= (command) ? CMD_FRAME : 0;
 595
 596         frame->control = RR | PF_BIT | (self->vr << 5);
 597
 598         irlap_queue_xmit(self, tx_skb);
 599 }
 600
 601 /*
 602  * Function irlap_send_rd_frame (self)
 603  *
 604  *    Request disconnect. Used by a secondary station to request the
 605  *    disconnection of the link.
 606  */
 607 void irlap_send_rd_frame(struct irlap_cb *self)
 608 {
 609         struct sk_buff *tx_skb;
 610         struct rd_frame *frame;
 611
 612         tx_skb = alloc_skb(sizeof(struct rd_frame), GFP_ATOMIC);
 613         if (!tx_skb)
 614                 return;
 615
 616         frame = (struct rd_frame *)skb_put(tx_skb, 2);
 617
 618         frame->caddr = self->caddr;
 619         frame->control = RD_RSP | PF_BIT;
 620
 621         irlap_queue_xmit(self, tx_skb);
 622 }
 623
 624 /*
 625  * Function irlap_recv_rr_frame (skb, info)
 626  *
 627  *    Received RR (Receive Ready) frame from peer station, no harm in
 628  *    making it inline since its called only from one single place
 629  *    (irlap_driver_rcv).
 630  */
 631 static inline void irlap_recv_rr_frame(struct irlap_cb *self,
 632                                        struct sk_buff *skb,
 633                                        struct irlap_info *info, int command)
 634 {
 635         info->nr = skb->data[1] >> 5;
 636
 637         /* Check if this is a command or a response frame */
 638         if (command)
 639                 irlap_do_event(self, RECV_RR_CMD, skb, info);
 640         else
 641                 irlap_do_event(self, RECV_RR_RSP, skb, info);
 642 }
 643
 644 /*
 645  * Function irlap_recv_rnr_frame (self, skb, info)
 646  *
 647  *    Received RNR (Receive Not Ready) frame from peer station
 648  *
 649  */
 650 static void irlap_recv_rnr_frame(struct irlap_cb *self, struct sk_buff *skb,
 651                                  struct irlap_info *info, int command)
 652 {
 653         info->nr = skb->data[1] >> 5;
 654
 655         pr_debug("%s(), nr=%d, %ld\n", __func__, info->nr, jiffies);
 656
 657         if (command)
 658                 irlap_do_event(self, RECV_RNR_CMD, skb, info);
 659         else
 660                 irlap_do_event(self, RECV_RNR_RSP, skb, info);
 661 }
 662
 663 static void irlap_recv_rej_frame(struct irlap_cb *self, struct sk_buff *skb,
 664                                  struct irlap_info *info, int command)
 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         info->nr = skb->data[1] >> 5;
 679
 680         /* Check if this is a command or a response frame */
 681         if (command)
 682                 irlap_do_event(self, RECV_SREJ_CMD, skb, info);
 683         else
 684                 irlap_do_event(self, RECV_SREJ_RSP, skb, info);
 685 }
 686
 687 static void irlap_recv_disc_frame(struct irlap_cb *self, struct sk_buff *skb,
 688                                   struct irlap_info *info, int command)
 689 {
 690         /* Check if this is a command or a response frame */
 691         if (command)
 692                 irlap_do_event(self, RECV_DISC_CMD, skb, info);
 693         else
 694                 irlap_do_event(self, RECV_RD_RSP, skb, info);
 695 }
 696
 697 /*
 698  * Function irlap_recv_ua_frame (skb, frame)
 699  *
 700  *    Received UA (Unnumbered Acknowledgement) frame
 701  *
 702  */
 703 static inline void irlap_recv_ua_frame(struct irlap_cb *self,
 704                                        struct sk_buff *skb,
 705                                        struct irlap_info *info)
 706 {
 707         irlap_do_event(self, RECV_UA_RSP, skb, info);
 708 }
 709
 710 /*
 711  * Function irlap_send_data_primary(self, skb)
 712  *
 713  *    Send I-frames as the primary station but without the poll bit set
 714  *
 715  */
 716 void irlap_send_data_primary(struct irlap_cb *self, struct sk_buff *skb)
 717 {
 718         struct sk_buff *tx_skb;
 719
 720         if (skb->data[1] == I_FRAME) {
 721
 722                 /*
 723                  *  Insert frame sequence number (Vs) in control field before
 724                  *  inserting into transmit window queue.
 725                  */
 726                 skb->data[1] = I_FRAME | (self->vs << 1);
 727
 728                 /*
 729                  *  Insert frame in store, in case of retransmissions
 730                  *  Increase skb reference count, see irlap_do_event()
 731                  */
 732                 skb_get(skb);
 733                 skb_queue_tail(&self->wx_list, skb);
 734
 735                 /* Copy buffer */
 736                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 737                 if (tx_skb == NULL) {
 738                         return;
 739                 }
 740
 741                 self->vs = (self->vs + 1) % 8;
 742                 self->ack_required = FALSE;
 743                 self->window -= 1;
 744
 745                 irlap_send_i_frame( self, tx_skb, CMD_FRAME);
 746         } else {
 747                 pr_debug("%s(), sending unreliable frame\n", __func__);
 748                 irlap_send_ui_frame(self, skb_get(skb), self->caddr, CMD_FRAME);
 749                 self->window -= 1;
 750         }
 751 }
 752 /*
 753  * Function irlap_send_data_primary_poll (self, skb)
 754  *
 755  *    Send I(nformation) frame as primary with poll bit set
 756  */
 757 void irlap_send_data_primary_poll(struct irlap_cb *self, struct sk_buff *skb)
 758 {
 759         struct sk_buff *tx_skb;
 760         int transmission_time;
 761
 762         /* Stop P timer */
 763         del_timer(&self->poll_timer);
 764
 765         /* Is this reliable or unreliable data? */
 766         if (skb->data[1] == I_FRAME) {
 767
 768                 /*
 769                  *  Insert frame sequence number (Vs) in control field before
 770                  *  inserting into transmit window queue.
 771                  */
 772                 skb->data[1] = I_FRAME | (self->vs << 1);
 773
 774                 /*
 775                  *  Insert frame in store, in case of retransmissions
 776                  *  Increase skb reference count, see irlap_do_event()
 777                  */
 778                 skb_get(skb);
 779                 skb_queue_tail(&self->wx_list, skb);
 780
 781                 /* Copy buffer */
 782                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 783                 if (tx_skb == NULL) {
 784                         return;
 785                 }
 786
 787                 /*
 788                  *  Set poll bit if necessary. We do this to the copied
 789                  *  skb, since retransmitted need to set or clear the poll
 790                  *  bit depending on when they are sent.
 791                  */
 792                 tx_skb->data[1] |= PF_BIT;
 793
 794                 self->vs = (self->vs + 1) % 8;
 795                 self->ack_required = FALSE;
 796
 797                 irlap_next_state(self, LAP_NRM_P);
 798                 irlap_send_i_frame(self, tx_skb, CMD_FRAME);
 799         } else {
 800                 pr_debug("%s(), sending unreliable frame\n", __func__);
 801
 802                 if (self->ack_required) {
 803                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, CMD_FRAME);
 804                         irlap_next_state(self, LAP_NRM_P);
 805                         irlap_send_rr_frame(self, CMD_FRAME);
 806                         self->ack_required = FALSE;
 807                 } else {
 808                         skb->data[1] |= PF_BIT;
 809                         irlap_next_state(self, LAP_NRM_P);
 810                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, CMD_FRAME);
 811                 }
 812         }
 813
 814         /* How much time we took for transmission of all frames.
 815          * We don't know, so let assume we used the full window. Jean II */
 816         transmission_time = self->final_timeout;
 817
 818         /* Reset parameter so that we can fill next window */
 819         self->window = self->window_size;
 820
 821 #ifdef CONFIG_IRDA_DYNAMIC_WINDOW
 822         /* Remove what we have not used. Just do a prorata of the
 823          * bytes left in window to window capacity.
 824          * See max_line_capacities[][] in qos.c for details. Jean II */
 825         transmission_time -= (self->final_timeout * self->bytes_left
 826                               / self->line_capacity);
 827         pr_debug("%s() adjusting transmission_time : ft=%d, bl=%d, lc=%d -> tt=%d\n",
 828                  __func__, self->final_timeout, self->bytes_left,
 829                  self->line_capacity, transmission_time);
 830
 831         /* We are allowed to transmit a maximum number of bytes again. */
 832         self->bytes_left = self->line_capacity;
 833 #endif /* CONFIG_IRDA_DYNAMIC_WINDOW */
 834
 835         /*
 836          * The network layer has a intermediate buffer between IrLAP
 837          * and the IrDA driver which can contain 8 frames. So, even
 838          * though IrLAP is currently sending the *last* frame of the
 839          * tx-window, the driver most likely has only just started
 840          * sending the *first* frame of the same tx-window.
 841          * I.e. we are always at the very beginning of or Tx window.
 842          * Now, we are supposed to set the final timer from the end
 843          * of our tx-window to let the other peer reply. So, we need
 844          * to add extra time to compensate for the fact that we
 845          * are really at the start of tx-window, otherwise the final timer
 846          * might expire before he can answer...
 847          * Jean II
 848          */
 849         irlap_start_final_timer(self, self->final_timeout + transmission_time);
 850
 851         /*
 852          * The clever amongst you might ask why we do this adjustement
 853          * only here, and not in all the other cases in irlap_event.c.
 854          * In all those other case, we only send a very short management
 855          * frame (few bytes), so the adjustement would be lost in the
 856          * noise...
 857          * The exception of course is irlap_resend_rejected_frame().
 858          * Jean II */
 859 }
 860
 861 /*
 862  * Function irlap_send_data_secondary_final (self, skb)
 863  *
 864  *    Send I(nformation) frame as secondary with final bit set
 865  *
 866  */
 867 void irlap_send_data_secondary_final(struct irlap_cb *self,
 868                                      struct sk_buff *skb)
 869 {
 870         struct sk_buff *tx_skb = NULL;
 871
 872         IRDA_ASSERT(self != NULL, return;);
 873         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 874         IRDA_ASSERT(skb != NULL, return;);
 875
 876         /* Is this reliable or unreliable data? */
 877         if (skb->data[1] == I_FRAME) {
 878
 879                 /*
 880                  *  Insert frame sequence number (Vs) in control field before
 881                  *  inserting into transmit window queue.
 882                  */
 883                 skb->data[1] = I_FRAME | (self->vs << 1);
 884
 885                 /*
 886                  *  Insert frame in store, in case of retransmissions
 887                  *  Increase skb reference count, see irlap_do_event()
 888                  */
 889                 skb_get(skb);
 890                 skb_queue_tail(&self->wx_list, skb);
 891
 892                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 893                 if (tx_skb == NULL) {
 894                         return;
 895                 }
 896
 897                 tx_skb->data[1] |= PF_BIT;
 898
 899                 self->vs = (self->vs + 1) % 8;
 900                 self->ack_required = FALSE;
 901
 902                 irlap_send_i_frame(self, tx_skb, RSP_FRAME);
 903         } else {
 904                 if (self->ack_required) {
 905                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, RSP_FRAME);
 906                         irlap_send_rr_frame(self, RSP_FRAME);
 907                         self->ack_required = FALSE;
 908                 } else {
 909                         skb->data[1] |= PF_BIT;
 910                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, RSP_FRAME);
 911                 }
 912         }
 913
 914         self->window = self->window_size;
 915 #ifdef CONFIG_IRDA_DYNAMIC_WINDOW
 916         /* We are allowed to transmit a maximum number of bytes again. */
 917         self->bytes_left = self->line_capacity;
 918 #endif /* CONFIG_IRDA_DYNAMIC_WINDOW */
 919
 920         irlap_start_wd_timer(self, self->wd_timeout);
 921 }
 922
 923 /*
 924  * Function irlap_send_data_secondary (self, skb)
 925  *
 926  *    Send I(nformation) frame as secondary without final bit set
 927  *
 928  */
 929 void irlap_send_data_secondary(struct irlap_cb *self, struct sk_buff *skb)
 930 {
 931         struct sk_buff *tx_skb = NULL;
 932
 933         /* Is this reliable or unreliable data? */
 934         if (skb->data[1] == I_FRAME) {
 935
 936                 /*
 937                  *  Insert frame sequence number (Vs) in control field before
 938                  *  inserting into transmit window queue.
 939                  */
 940                 skb->data[1] = I_FRAME | (self->vs << 1);
 941
 942                 /*
 943                  *  Insert frame in store, in case of retransmissions
 944                  *  Increase skb reference count, see irlap_do_event()
 945                  */
 946                 skb_get(skb);
 947                 skb_queue_tail(&self->wx_list, skb);
 948
 949                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 950                 if (tx_skb == NULL) {
 951                         return;
 952                 }
 953
 954                 self->vs = (self->vs + 1) % 8;
 955                 self->ack_required = FALSE;
 956                 self->window -= 1;
 957
 958                 irlap_send_i_frame(self, tx_skb, RSP_FRAME);
 959         } else {
 960                 irlap_send_ui_frame(self, skb_get(skb), self->caddr, RSP_FRAME);
 961                 self->window -= 1;
 962         }
 963 }
 964
 965 /*
 966  * Function irlap_resend_rejected_frames (nr)
 967  *
 968  *    Resend frames which has not been acknowledged. Should be safe to
 969  *    traverse the list without locking it since this function will only be
 970  *    called from interrupt context (BH)
 971  */
 972 void irlap_resend_rejected_frames(struct irlap_cb *self, int command)
 973 {
 974         struct sk_buff *tx_skb;
 975         struct sk_buff *skb;
 976
 977         IRDA_ASSERT(self != NULL, return;);
 978         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 979
 980         /*  Resend unacknowledged frame(s) */
 981         skb_queue_walk(&self->wx_list, skb) {
 982                 irlap_wait_min_turn_around(self, &self->qos_tx);
 983
 984                 /* We copy the skb to be retransmitted since we will have to
 985                  * modify it. Cloning will confuse packet sniffers
 986                  */
 987                 /* tx_skb = skb_clone( skb, GFP_ATOMIC); */
 988                 tx_skb = skb_copy(skb, GFP_ATOMIC);
 989                 if (!tx_skb) {
 990                         pr_debug("%s(), unable to copy\n", __func__);
 991                         return;
 992                 }
 993
 994                 /* Clear old Nr field + poll bit */
 995                 tx_skb->data[1] &= 0x0f;
 996
 997                 /*
 998                  *  Set poll bit on the last frame retransmitted
 999                  */
1000                 if (skb_queue_is_last(&self->wx_list, skb))
1001                         tx_skb->data[1] |= PF_BIT; /* Set p/f bit */
1002                 else
1003                         tx_skb->data[1] &= ~PF_BIT; /* Clear p/f bit */
1004
1005                 irlap_send_i_frame(self, tx_skb, command);
1006         }
1007 #if 0 /* Not yet */
1008         /*
1009          *  We can now fill the window with additional data frames
1010          */
1011         while (!skb_queue_empty(&self->txq)) {
1012
1013                 pr_debug("%s(), sending additional frames!\n", __func__);
1014                 if (self->window > 0) {
1015                         skb = skb_dequeue( &self->txq);
1016                         IRDA_ASSERT(skb != NULL, return;);
1017
1018                         /*
1019                          *  If send window > 1 then send frame with pf
1020                          *  bit cleared
1021                          */
1022                         if ((self->window > 1) &&
1023                             !skb_queue_empty(&self->txq)) {
1024                                 irlap_send_data_primary(self, skb);
1025                         } else {
1026                                 irlap_send_data_primary_poll(self, skb);
1027                         }
1028                         kfree_skb(skb);
1029                 }
1030         }
1031 #endif
1032 }
1033
1034 void irlap_resend_rejected_frame(struct irlap_cb *self, int command)
1035 {
1036         struct sk_buff *tx_skb;
1037         struct sk_buff *skb;
1038
1039         IRDA_ASSERT(self != NULL, return;);
1040         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
1041
1042         /*  Resend unacknowledged frame(s) */
1043         skb = skb_peek(&self->wx_list);
1044         if (skb != NULL) {
1045                 irlap_wait_min_turn_around(self, &self->qos_tx);
1046
1047                 /* We copy the skb to be retransmitted since we will have to
1048                  * modify it. Cloning will confuse packet sniffers
1049                  */
1050                 /* tx_skb = skb_clone( skb, GFP_ATOMIC); */
1051                 tx_skb = skb_copy(skb, GFP_ATOMIC);
1052                 if (!tx_skb) {
1053                         pr_debug("%s(), unable to copy\n", __func__);
1054                         return;
1055                 }
1056
1057                 /* Clear old Nr field + poll bit */
1058                 tx_skb->data[1] &= 0x0f;
1059
1060                 /*  Set poll/final bit */
1061                 tx_skb->data[1] |= PF_BIT; /* Set p/f bit */
1062
1063                 irlap_send_i_frame(self, tx_skb, command);
1064         }
1065 }
1066
1067 /*
1068  * Function irlap_send_ui_frame (self, skb, command)
1069  *
1070  *    Contruct and transmit an Unnumbered Information (UI) frame
1071  *
1072  */
1073 void irlap_send_ui_frame(struct irlap_cb *self, struct sk_buff *skb,
1074                          __u8 caddr, int command)
1075 {
1076         IRDA_ASSERT(self != NULL, return;);
1077         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
1078         IRDA_ASSERT(skb != NULL, return;);
1079
1080         /* Insert connection address */
1081         skb->data[0] = caddr | ((command) ? CMD_FRAME : 0);
1082
1083         irlap_queue_xmit(self, skb);
1084 }
1085
1086 /*
1087  * Function irlap_send_i_frame (skb)
1088  *
1089  *    Contruct and transmit Information (I) frame
1090  */
1091 static void irlap_send_i_frame(struct irlap_cb *self, struct sk_buff *skb,
1092                                int command)
1093 {
1094         /* Insert connection address */
1095         skb->data[0] = self->caddr;
1096         skb->data[0] |= (command) ? CMD_FRAME : 0;
1097
1098         /* Insert next to receive (Vr) */
1099         skb->data[1] |= (self->vr << 5);  /* insert nr */
1100
1101         irlap_queue_xmit(self, skb);
1102 }
1103
1104 /*
1105  * Function irlap_recv_i_frame (skb, frame)
1106  *
1107  *    Receive and parse an I (Information) frame, no harm in making it inline
1108  *    since it's called only from one single place (irlap_driver_rcv).
1109  */
1110 static inline void irlap_recv_i_frame(struct irlap_cb *self,
1111                                       struct sk_buff *skb,
1112                                       struct irlap_info *info, int command)
1113 {
1114         info->nr = skb->data[1] >> 5;          /* Next to receive */
1115         info->pf = skb->data[1] & PF_BIT;      /* Final bit */
1116         info->ns = (skb->data[1] >> 1) & 0x07; /* Next to send */
1117
1118         /* Check if this is a command or a response frame */
1119         if (command)
1120                 irlap_do_event(self, RECV_I_CMD, skb, info);
1121         else
1122                 irlap_do_event(self, RECV_I_RSP, skb, info);
1123 }
1124
1125 /*
1126  * Function irlap_recv_ui_frame (self, skb, info)
1127  *
1128  *    Receive and parse an Unnumbered Information (UI) frame
1129  *
1130  */
1131 static void irlap_recv_ui_frame(struct irlap_cb *self, struct sk_buff *skb,
1132                                 struct irlap_info *info)
1133 {
1134         info->pf = skb->data[1] & PF_BIT;      /* Final bit */
1135
1136         irlap_do_event(self, RECV_UI_FRAME, skb, info);
1137 }
1138
1139 /*
1140  * Function irlap_recv_frmr_frame (skb, frame)
1141  *
1142  *    Received Frame Reject response.
1143  *
1144  */
1145 static void irlap_recv_frmr_frame(struct irlap_cb *self, struct sk_buff *skb,
1146                                   struct irlap_info *info)
1147 {
1148         __u8 *frame;
1149         int w, x, y, z;
1150
1151         IRDA_ASSERT(self != NULL, return;);
1152         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
1153         IRDA_ASSERT(skb != NULL, return;);
1154         IRDA_ASSERT(info != NULL, return;);
1155
1156         if (!pskb_may_pull(skb, 4)) {
1157                 net_err_ratelimited("%s: frame too short!\n", __func__);
1158                 return;
1159         }
1160
1161         frame = skb->data;
1162
1163         info->nr = frame[2] >> 5;          /* Next to receive */
1164         info->pf = frame[2] & PF_BIT;      /* Final bit */
1165         info->ns = (frame[2] >> 1) & 0x07; /* Next to send */
1166
1167         w = frame[3] & 0x01;
1168         x = frame[3] & 0x02;
1169         y = frame[3] & 0x04;
1170         z = frame[3] & 0x08;
1171
1172         if (w) {
1173                 pr_debug("Rejected control field is undefined or not implemented\n");
1174         }
1175         if (x) {
1176                 pr_debug("Rejected control field was invalid because it contained a non permitted I field\n");
1177         }
1178         if (y) {
1179                 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");
1180         }
1181         if (z) {
1182                 pr_debug("Rejected control field control field contained an invalid Nr count\n");
1183         }
1184         irlap_do_event(self, RECV_FRMR_RSP, skb, info);
1185 }
1186
1187 /*
1188  * Function irlap_send_test_frame (self, daddr)
1189  *
1190  *    Send a test frame response
1191  *
1192  */
1193 void irlap_send_test_frame(struct irlap_cb *self, __u8 caddr, __u32 daddr,
1194                            struct sk_buff *cmd)
1195 {
1196         struct sk_buff *tx_skb;
1197         struct test_frame *frame;
1198         __u8 *info;
1199
1200         tx_skb = alloc_skb(cmd->len + sizeof(struct test_frame), GFP_ATOMIC);
1201         if (!tx_skb)
1202                 return;
1203
1204         /* Broadcast frames must include saddr and daddr fields */
1205         if (caddr == CBROADCAST) {
1206                 frame = (struct test_frame *)
1207                         skb_put(tx_skb, sizeof(struct test_frame));
1208
1209                 /* Insert the swapped addresses */
1210                 frame->saddr = cpu_to_le32(self->saddr);
1211                 frame->daddr = cpu_to_le32(daddr);
1212         } else
1213                 frame = (struct test_frame *) skb_put(tx_skb, LAP_ADDR_HEADER + LAP_CTRL_HEADER);
1214
1215         frame->caddr = caddr;
1216         frame->control = TEST_RSP | PF_BIT;
1217
1218         /* Copy info */
1219         info = skb_put(tx_skb, cmd->len);
1220         memcpy(info, cmd->data, cmd->len);
1221
1222         /* Return to sender */
1223         irlap_wait_min_turn_around(self, &self->qos_tx);
1224         irlap_queue_xmit(self, tx_skb);
1225 }
1226
1227 /*
1228  * Function irlap_recv_test_frame (self, skb)
1229  *
1230  *    Receive a test frame
1231  *
1232  */
1233 static void irlap_recv_test_frame(struct irlap_cb *self, struct sk_buff *skb,
1234                                   struct irlap_info *info, int command)
1235 {
1236         struct test_frame *frame;
1237
1238         if (!pskb_may_pull(skb, sizeof(*frame))) {
1239                 net_err_ratelimited("%s: frame too short!\n", __func__);
1240                 return;
1241         }
1242         frame = (struct test_frame *) skb->data;
1243
1244         /* Broadcast frames must carry saddr and daddr fields */
1245         if (info->caddr == CBROADCAST) {
1246                 if (skb->len < sizeof(struct test_frame)) {
1247                         pr_debug("%s() test frame too short!\n",
1248                                  __func__);
1249                         return;
1250                 }
1251
1252                 /* Read and swap addresses */
1253                 info->daddr = le32_to_cpu(frame->saddr);
1254                 info->saddr = le32_to_cpu(frame->daddr);
1255
1256                 /* Make sure frame is addressed to us */
1257                 if ((info->saddr != self->saddr) &&
1258                     (info->saddr != BROADCAST)) {
1259                         return;
1260                 }
1261         }
1262
1263         if (command)
1264                 irlap_do_event(self, RECV_TEST_CMD, skb, info);
1265         else
1266                 irlap_do_event(self, RECV_TEST_RSP, skb, info);
1267 }
1268
1269 /*
1270  * Function irlap_driver_rcv (skb, netdev, ptype)
1271  *
1272  *    Called when a frame is received. Dispatches the right receive function
1273  *    for processing of the frame.
1274  *
1275  * Note on skb management :
1276  * After calling the higher layers of the IrDA stack, we always
1277  * kfree() the skb, which drop the reference count (and potentially
1278  * destroy it).
1279  * If a higher layer of the stack want to keep the skb around (to put
1280  * in a queue or pass it to the higher layer), it will need to use
1281  * skb_get() to keep a reference on it. This is usually done at the
1282  * LMP level in irlmp.c.
1283  * Jean II
1284  */
1285 int irlap_driver_rcv(struct sk_buff *skb, struct net_device *dev,
1286                      struct packet_type *ptype, struct net_device *orig_dev)
1287 {
1288         struct irlap_info info;
1289         struct irlap_cb *self;
1290         int command;
1291         __u8 control;
1292         int ret = -1;
1293
1294         if (!net_eq(dev_net(dev), &init_net))
1295                 goto out;
1296
1297         /* FIXME: should we get our own field? */
1298         self = (struct irlap_cb *) dev->atalk_ptr;
1299
1300         /* If the net device is down, then IrLAP is gone! */
1301         if (!self || self->magic != LAP_MAGIC)
1302                 goto err;
1303
1304         /* We are no longer an "old" protocol, so we need to handle
1305          * share and non linear skbs. This should never happen, so
1306          * we don't need to be clever about it. Jean II */
1307         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
1308                 net_err_ratelimited("%s: can't clone shared skb!\n", __func__);
1309                 goto err;
1310         }
1311
1312         /* Check if frame is large enough for parsing */
1313         if (!pskb_may_pull(skb, 2)) {
1314                 net_err_ratelimited("%s: frame too short!\n", __func__);
1315                 goto err;
1316         }
1317
1318         command    = skb->data[0] & CMD_FRAME;
1319         info.caddr = skb->data[0] & CBROADCAST;
1320
1321         info.pf      = skb->data[1] &  PF_BIT;
1322         info.control = skb->data[1] & ~PF_BIT; /* Mask away poll/final bit */
1323
1324         control = info.control;
1325
1326         /*  First we check if this frame has a valid connection address */
1327         if ((info.caddr != self->caddr) && (info.caddr != CBROADCAST)) {
1328                 pr_debug("%s(), wrong connection address!\n",
1329                          __func__);
1330                 goto out;
1331         }
1332         /*
1333          *  Optimize for the common case and check if the frame is an
1334          *  I(nformation) frame. Only I-frames have bit 0 set to 0
1335          */
1336         if (~control & 0x01) {
1337                 irlap_recv_i_frame(self, skb, &info, command);
1338                 goto out;
1339         }
1340         /*
1341          *  We now check is the frame is an S(upervisory) frame. Only
1342          *  S-frames have bit 0 set to 1 and bit 1 set to 0
1343          */
1344         if (~control & 0x02) {
1345                 /*
1346                  *  Received S(upervisory) frame, check which frame type it is
1347                  *  only the first nibble is of interest
1348                  */
1349                 switch (control & 0x0f) {
1350                 case RR:
1351                         irlap_recv_rr_frame(self, skb, &info, command);
1352                         break;
1353                 case RNR:
1354                         irlap_recv_rnr_frame(self, skb, &info, command);
1355                         break;
1356                 case REJ:
1357                         irlap_recv_rej_frame(self, skb, &info, command);
1358                         break;
1359                 case SREJ:
1360                         irlap_recv_srej_frame(self, skb, &info, command);
1361                         break;
1362                 default:
1363                         net_warn_ratelimited("%s: Unknown S-frame %02x received!\n",
1364                                              __func__, info.control);
1365                         break;
1366                 }
1367                 goto out;
1368         }
1369         /*
1370          *  This must be a C(ontrol) frame
1371          */
1372         switch (control) {
1373         case XID_RSP:
1374                 irlap_recv_discovery_xid_rsp(self, skb, &info);
1375                 break;
1376         case XID_CMD:
1377                 irlap_recv_discovery_xid_cmd(self, skb, &info);
1378                 break;
1379         case SNRM_CMD:
1380                 irlap_recv_snrm_cmd(self, skb, &info);
1381                 break;
1382         case DM_RSP:
1383                 irlap_do_event(self, RECV_DM_RSP, skb, &info);
1384                 break;
1385         case DISC_CMD: /* And RD_RSP since they have the same value */
1386                 irlap_recv_disc_frame(self, skb, &info, command);
1387                 break;
1388         case TEST_CMD:
1389                 irlap_recv_test_frame(self, skb, &info, command);
1390                 break;
1391         case UA_RSP:
1392                 irlap_recv_ua_frame(self, skb, &info);
1393                 break;
1394         case FRMR_RSP:
1395                 irlap_recv_frmr_frame(self, skb, &info);
1396                 break;
1397         case UI_FRAME:
1398                 irlap_recv_ui_frame(self, skb, &info);
1399                 break;
1400         default:
1401                 net_warn_ratelimited("%s: Unknown frame %02x received!\n",
1402                                      __func__, info.control);
1403                 break;
1404         }
1405 out:
1406         ret = 0;
1407 err:
1408         /* Always drop our reference on the skb */
1409         dev_kfree_skb(skb);
1410         return ret;
1411 }