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   1 /*********************************************************************
   2  *
   3  * Filename:      irlap_frame.c
   4  * Version:       1.0
   5  * Description:   Build and transmit IrLAP frames
   6  * Status:        Stable
   7  * Author:        Dag Brattli <dagb@cs.uit.no>
   8  * Created at:    Tue Aug 19 10:27:26 1997
   9  * Modified at:   Wed Jan  5 08:59:04 2000
  10  * Modified by:   Dag Brattli <dagb@cs.uit.no>
  11  *
  12  *     Copyright (c) 1998-2000 Dag Brattli <dagb@cs.uit.no>,
  13  *     All Rights Reserved.
  14  *     Copyright (c) 2000-2003 Jean Tourrilhes <jt@hpl.hp.com>
  15  *
  16  *     This program is free software; you can redistribute it and/or
  17  *     modify it under the terms of the GNU General Public License as
  18  *     published by the Free Software Foundation; either version 2 of
  19  *     the License, or (at your option) any later version.
  20  *
  21  *     Neither Dag Brattli nor University of Tromsø admit liability nor
  22  *     provide warranty for any of this software. This material is
  23  *     provided "AS-IS" and at no charge.
  24  *
  25  ********************************************************************/
  26
  27 #include <linux/skbuff.h>
  28 #include <linux/if.h>
  29 #include <linux/if_ether.h>
  30 #include <linux/netdevice.h>
  31 #include <linux/irda.h>
  32
  33 #include <net/pkt_sched.h>
  34 #include <net/sock.h>
  35
  36 #include <asm/byteorder.h>
  37
  38 #include <net/irda/irda.h>
  39 #include <net/irda/irda_device.h>
  40 #include <net/irda/irlap.h>
  41 #include <net/irda/wrapper.h>
  42 #include <net/irda/timer.h>
  43 #include <net/irda/irlap_frame.h>
  44 #include <net/irda/qos.h>
  45
  46 static void irlap_send_i_frame(struct irlap_cb *self, struct sk_buff *skb,
  47                                int command);
  48
  49 /*
  50  * Function irlap_insert_info (self, skb)
  51  *
  52  *    Insert minimum turnaround time and speed information into the skb. We
  53  *    need to do this since it's per packet relevant information. Safe to
  54  *    have this function inlined since it's only called from one place
  55  */
  56 static inline void irlap_insert_info(struct irlap_cb *self,
  57                                      struct sk_buff *skb)
  58 {
  59         struct irda_skb_cb *cb = (struct irda_skb_cb *) skb->cb;
  60
  61         /*
  62          * Insert MTT (min. turn time) and speed into skb, so that the
  63          * device driver knows which settings to use
  64          */
  65         cb->magic = LAP_MAGIC;
  66         cb->mtt = self->mtt_required;
  67         cb->next_speed = self->speed;
  68
  69         /* Reset */
  70         self->mtt_required = 0;
  71
  72         /*
  73          * Delay equals negotiated BOFs count, plus the number of BOFs to
  74          * force the negotiated minimum turnaround time
  75          */
  76         cb->xbofs = self->bofs_count;
  77         cb->next_xbofs = self->next_bofs;
  78         cb->xbofs_delay = self->xbofs_delay;
  79
  80         /* Reset XBOF's delay (used only for getting min turn time) */
  81         self->xbofs_delay = 0;
  82         /* Put the correct xbofs value for the next packet */
  83         self->bofs_count = self->next_bofs;
  84 }
  85
  86 /*
  87  * Function irlap_queue_xmit (self, skb)
  88  *
  89  *    A little wrapper for dev_queue_xmit, so we can insert some common
  90  *    code into it.
  91  */
  92 void irlap_queue_xmit(struct irlap_cb *self, struct sk_buff *skb)
  93 {
  94         /* Some common init stuff */
  95         skb->dev = self->netdev;
  96         skb_reset_mac_header(skb);
  97         skb_reset_network_header(skb);
  98         skb_reset_transport_header(skb);
  99         skb->protocol = htons(ETH_P_IRDA);
 100         skb->priority = TC_PRIO_BESTEFFORT;
 101
 102         irlap_insert_info(self, skb);
 103
 104         if (unlikely(self->mode & IRDA_MODE_MONITOR)) {
 105                 IRDA_DEBUG(3, "%s(): %s is in monitor mode\n", __func__,
 106                            self->netdev->name);
 107                 dev_kfree_skb(skb);
 108                 return;
 109         }
 110
 111         dev_queue_xmit(skb);
 112 }
 113
 114 /*
 115  * Function irlap_send_snrm_cmd (void)
 116  *
 117  *    Transmits a connect SNRM command frame
 118  */
 119 void irlap_send_snrm_frame(struct irlap_cb *self, struct qos_info *qos)
 120 {
 121         struct sk_buff *tx_skb;
 122         struct snrm_frame *frame;
 123         int ret;
 124
 125         IRDA_ASSERT(self != NULL, return;);
 126         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 127
 128         /* Allocate frame */
 129         tx_skb = alloc_skb(sizeof(struct snrm_frame) +
 130                            IRLAP_NEGOCIATION_PARAMS_LEN,
 131                            GFP_ATOMIC);
 132         if (!tx_skb)
 133                 return;
 134
 135         frame = (struct snrm_frame *) skb_put(tx_skb, 2);
 136
 137         /* Insert connection address field */
 138         if (qos)
 139                 frame->caddr = CMD_FRAME | CBROADCAST;
 140         else
 141                 frame->caddr = CMD_FRAME | self->caddr;
 142
 143         /* Insert control field */
 144         frame->control = SNRM_CMD | PF_BIT;
 145
 146         /*
 147          *  If we are establishing a connection then insert QoS parameters
 148          */
 149         if (qos) {
 150                 skb_put(tx_skb, 9); /* 25 left */
 151                 frame->saddr = cpu_to_le32(self->saddr);
 152                 frame->daddr = cpu_to_le32(self->daddr);
 153
 154                 frame->ncaddr = self->caddr;
 155
 156                 ret = irlap_insert_qos_negotiation_params(self, tx_skb);
 157                 if (ret < 0) {
 158                         dev_kfree_skb(tx_skb);
 159                         return;
 160                 }
 161         }
 162         irlap_queue_xmit(self, tx_skb);
 163 }
 164
 165 /*
 166  * Function irlap_recv_snrm_cmd (skb, info)
 167  *
 168  *    Received SNRM (Set Normal Response Mode) command frame
 169  *
 170  */
 171 static void irlap_recv_snrm_cmd(struct irlap_cb *self, struct sk_buff *skb,
 172                                 struct irlap_info *info)
 173 {
 174         struct snrm_frame *frame;
 175
 176         if (pskb_may_pull(skb,sizeof(struct snrm_frame))) {
 177                 frame = (struct snrm_frame *) skb->data;
 178
 179                 /* Copy the new connection address ignoring the C/R bit */
 180                 info->caddr = frame->ncaddr & 0xFE;
 181
 182                 /* Check if the new connection address is valid */
 183                 if ((info->caddr == 0x00) || (info->caddr == 0xfe)) {
 184                         IRDA_DEBUG(3, "%s(), invalid connection address!\n",
 185                                    __func__);
 186                         return;
 187                 }
 188
 189                 /* Copy peer device address */
 190                 info->daddr = le32_to_cpu(frame->saddr);
 191                 info->saddr = le32_to_cpu(frame->daddr);
 192
 193                 /* Only accept if addressed directly to us */
 194                 if (info->saddr != self->saddr) {
 195                         IRDA_DEBUG(2, "%s(), not addressed to us!\n",
 196                                    __func__);
 197                         return;
 198                 }
 199                 irlap_do_event(self, RECV_SNRM_CMD, skb, info);
 200         } else {
 201                 /* Signal that this SNRM frame does not contain and I-field */
 202                 irlap_do_event(self, RECV_SNRM_CMD, skb, NULL);
 203         }
 204 }
 205
 206 /*
 207  * Function irlap_send_ua_response_frame (qos)
 208  *
 209  *    Send UA (Unnumbered Acknowledgement) frame
 210  *
 211  */
 212 void irlap_send_ua_response_frame(struct irlap_cb *self, struct qos_info *qos)
 213 {
 214         struct sk_buff *tx_skb;
 215         struct ua_frame *frame;
 216         int ret;
 217
 218         IRDA_DEBUG(2, "%s() <%ld>\n", __func__, jiffies);
 219
 220         IRDA_ASSERT(self != NULL, return;);
 221         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 222
 223         /* Allocate frame */
 224         tx_skb = alloc_skb(sizeof(struct ua_frame) +
 225                            IRLAP_NEGOCIATION_PARAMS_LEN,
 226                            GFP_ATOMIC);
 227         if (!tx_skb)
 228                 return;
 229
 230         frame = (struct ua_frame *) skb_put(tx_skb, 10);
 231
 232         /* Build UA response */
 233         frame->caddr = self->caddr;
 234         frame->control = UA_RSP | PF_BIT;
 235
 236         frame->saddr = cpu_to_le32(self->saddr);
 237         frame->daddr = cpu_to_le32(self->daddr);
 238
 239         /* Should we send QoS negotiation parameters? */
 240         if (qos) {
 241                 ret = irlap_insert_qos_negotiation_params(self, tx_skb);
 242                 if (ret < 0) {
 243                         dev_kfree_skb(tx_skb);
 244                         return;
 245                 }
 246         }
 247
 248         irlap_queue_xmit(self, tx_skb);
 249 }
 250
 251
 252 /*
 253  * Function irlap_send_dm_frame (void)
 254  *
 255  *    Send disconnected mode (DM) frame
 256  *
 257  */
 258 void irlap_send_dm_frame( struct irlap_cb *self)
 259 {
 260         struct sk_buff *tx_skb = NULL;
 261         struct dm_frame *frame;
 262
 263         IRDA_ASSERT(self != NULL, return;);
 264         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 265
 266         tx_skb = alloc_skb(sizeof(struct dm_frame), GFP_ATOMIC);
 267         if (!tx_skb)
 268                 return;
 269
 270         frame = (struct dm_frame *)skb_put(tx_skb, 2);
 271
 272         if (self->state == LAP_NDM)
 273                 frame->caddr = CBROADCAST;
 274         else
 275                 frame->caddr = self->caddr;
 276
 277         frame->control = DM_RSP | PF_BIT;
 278
 279         irlap_queue_xmit(self, tx_skb);
 280 }
 281
 282 /*
 283  * Function irlap_send_disc_frame (void)
 284  *
 285  *    Send disconnect (DISC) frame
 286  *
 287  */
 288 void irlap_send_disc_frame(struct irlap_cb *self)
 289 {
 290         struct sk_buff *tx_skb = NULL;
 291         struct disc_frame *frame;
 292
 293         IRDA_DEBUG(3, "%s()\n", __func__);
 294
 295         IRDA_ASSERT(self != NULL, return;);
 296         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 297
 298         tx_skb = alloc_skb(sizeof(struct disc_frame), GFP_ATOMIC);
 299         if (!tx_skb)
 300                 return;
 301
 302         frame = (struct disc_frame *)skb_put(tx_skb, 2);
 303
 304         frame->caddr = self->caddr | CMD_FRAME;
 305         frame->control = DISC_CMD | PF_BIT;
 306
 307         irlap_queue_xmit(self, tx_skb);
 308 }
 309
 310 /*
 311  * Function irlap_send_discovery_xid_frame (S, s, command)
 312  *
 313  *    Build and transmit a XID (eXchange station IDentifier) discovery
 314  *    frame.
 315  */
 316 void irlap_send_discovery_xid_frame(struct irlap_cb *self, int S, __u8 s,
 317                                     __u8 command, discovery_t *discovery)
 318 {
 319         struct sk_buff *tx_skb = NULL;
 320         struct xid_frame *frame;
 321         __u32 bcast = BROADCAST;
 322         __u8 *info;
 323
 324         IRDA_DEBUG(4, "%s(), s=%d, S=%d, command=%d\n", __func__,
 325                    s, S, command);
 326
 327         IRDA_ASSERT(self != NULL, return;);
 328         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 329         IRDA_ASSERT(discovery != NULL, return;);
 330
 331         tx_skb = alloc_skb(sizeof(struct xid_frame) + IRLAP_DISCOVERY_INFO_LEN,
 332                            GFP_ATOMIC);
 333         if (!tx_skb)
 334                 return;
 335
 336         skb_put(tx_skb, 14);
 337         frame = (struct xid_frame *) tx_skb->data;
 338
 339         if (command) {
 340                 frame->caddr = CBROADCAST | CMD_FRAME;
 341                 frame->control =  XID_CMD | PF_BIT;
 342         } else {
 343                 frame->caddr = CBROADCAST;
 344                 frame->control =  XID_RSP | PF_BIT;
 345         }
 346         frame->ident = XID_FORMAT;
 347
 348         frame->saddr = cpu_to_le32(self->saddr);
 349
 350         if (command)
 351                 frame->daddr = cpu_to_le32(bcast);
 352         else
 353                 frame->daddr = cpu_to_le32(discovery->data.daddr);
 354
 355         switch (S) {
 356         case 1:
 357                 frame->flags = 0x00;
 358                 break;
 359         case 6:
 360                 frame->flags = 0x01;
 361                 break;
 362         case 8:
 363                 frame->flags = 0x02;
 364                 break;
 365         case 16:
 366                 frame->flags = 0x03;
 367                 break;
 368         default:
 369                 frame->flags = 0x02;
 370                 break;
 371         }
 372
 373         frame->slotnr = s;
 374         frame->version = 0x00;
 375
 376         /*
 377          *  Provide info for final slot only in commands, and for all
 378          *  responses. Send the second byte of the hint only if the
 379          *  EXTENSION bit is set in the first byte.
 380          */
 381         if (!command || (frame->slotnr == 0xff)) {
 382                 int len;
 383
 384                 if (discovery->data.hints[0] & HINT_EXTENSION) {
 385                         info = skb_put(tx_skb, 2);
 386                         info[0] = discovery->data.hints[0];
 387                         info[1] = discovery->data.hints[1];
 388                 } else {
 389                         info = skb_put(tx_skb, 1);
 390                         info[0] = discovery->data.hints[0];
 391                 }
 392                 info = skb_put(tx_skb, 1);
 393                 info[0] = discovery->data.charset;
 394
 395                 len = IRDA_MIN(discovery->name_len, skb_tailroom(tx_skb));
 396                 info = skb_put(tx_skb, len);
 397                 memcpy(info, discovery->data.info, len);
 398         }
 399         irlap_queue_xmit(self, tx_skb);
 400 }
 401
 402 /*
 403  * Function irlap_recv_discovery_xid_rsp (skb, info)
 404  *
 405  *    Received a XID discovery response
 406  *
 407  */
 408 static void irlap_recv_discovery_xid_rsp(struct irlap_cb *self,
 409                                          struct sk_buff *skb,
 410                                          struct irlap_info *info)
 411 {
 412         struct xid_frame *xid;
 413         discovery_t *discovery = NULL;
 414         __u8 *discovery_info;
 415         char *text;
 416
 417         IRDA_DEBUG(4, "%s()\n", __func__);
 418
 419         IRDA_ASSERT(self != NULL, return;);
 420         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 421
 422         if (!pskb_may_pull(skb, sizeof(struct xid_frame))) {
 423                 IRDA_ERROR("%s: frame too short!\n", __func__);
 424                 return;
 425         }
 426
 427         xid = (struct xid_frame *) skb->data;
 428
 429         info->daddr = le32_to_cpu(xid->saddr);
 430         info->saddr = le32_to_cpu(xid->daddr);
 431
 432         /* Make sure frame is addressed to us */
 433         if ((info->saddr != self->saddr) && (info->saddr != BROADCAST)) {
 434                 IRDA_DEBUG(0, "%s(), frame is not addressed to us!\n",
 435                            __func__);
 436                 return;
 437         }
 438
 439         if ((discovery = kzalloc(sizeof(discovery_t), GFP_ATOMIC)) == NULL) {
 440                 IRDA_WARNING("%s: kmalloc failed!\n", __func__);
 441                 return;
 442         }
 443
 444         discovery->data.daddr = info->daddr;
 445         discovery->data.saddr = self->saddr;
 446         discovery->timestamp = jiffies;
 447
 448         IRDA_DEBUG(4, "%s(), daddr=%08x\n", __func__,
 449                    discovery->data.daddr);
 450
 451         discovery_info = skb_pull(skb, sizeof(struct xid_frame));
 452
 453         /* Get info returned from peer */
 454         discovery->data.hints[0] = discovery_info[0];
 455         if (discovery_info[0] & HINT_EXTENSION) {
 456                 IRDA_DEBUG(4, "EXTENSION\n");
 457                 discovery->data.hints[1] = discovery_info[1];
 458                 discovery->data.charset = discovery_info[2];
 459                 text = (char *) &discovery_info[3];
 460         } else {
 461                 discovery->data.hints[1] = 0;
 462                 discovery->data.charset = discovery_info[1];
 463                 text = (char *) &discovery_info[2];
 464         }
 465         /*
 466          *  Terminate info string, should be safe since this is where the
 467          *  FCS bytes resides.
 468          */
 469         skb->data[skb->len] = '\0';
 470         strncpy(discovery->data.info, text, NICKNAME_MAX_LEN);
 471         discovery->name_len = strlen(discovery->data.info);
 472
 473         info->discovery = discovery;
 474
 475         irlap_do_event(self, RECV_DISCOVERY_XID_RSP, skb, info);
 476 }
 477
 478 /*
 479  * Function irlap_recv_discovery_xid_cmd (skb, info)
 480  *
 481  *    Received a XID discovery command
 482  *
 483  */
 484 static void irlap_recv_discovery_xid_cmd(struct irlap_cb *self,
 485                                          struct sk_buff *skb,
 486                                          struct irlap_info *info)
 487 {
 488         struct xid_frame *xid;
 489         discovery_t *discovery = NULL;
 490         __u8 *discovery_info;
 491         char *text;
 492
 493         if (!pskb_may_pull(skb, sizeof(struct xid_frame))) {
 494                 IRDA_ERROR("%s: frame too short!\n", __func__);
 495                 return;
 496         }
 497
 498         xid = (struct xid_frame *) skb->data;
 499
 500         info->daddr = le32_to_cpu(xid->saddr);
 501         info->saddr = le32_to_cpu(xid->daddr);
 502
 503         /* Make sure frame is addressed to us */
 504         if ((info->saddr != self->saddr) && (info->saddr != BROADCAST)) {
 505                 IRDA_DEBUG(0, "%s(), frame is not addressed to us!\n",
 506                            __func__);
 507                 return;
 508         }
 509
 510         switch (xid->flags & 0x03) {
 511         case 0x00:
 512                 info->S = 1;
 513                 break;
 514         case 0x01:
 515                 info->S = 6;
 516                 break;
 517         case 0x02:
 518                 info->S = 8;
 519                 break;
 520         case 0x03:
 521                 info->S = 16;
 522                 break;
 523         default:
 524                 /* Error!! */
 525                 return;
 526         }
 527         info->s = xid->slotnr;
 528
 529         discovery_info = skb_pull(skb, sizeof(struct xid_frame));
 530
 531         /*
 532          *  Check if last frame
 533          */
 534         if (info->s == 0xff) {
 535                 /* Check if things are sane at this point... */
 536                 if((discovery_info == NULL) ||
 537                    !pskb_may_pull(skb, 3)) {
 538                         IRDA_ERROR("%s: discovery frame too short!\n",
 539                                    __func__);
 540                         return;
 541                 }
 542
 543                 /*
 544                  *  We now have some discovery info to deliver!
 545                  */
 546                 discovery = kmalloc(sizeof(discovery_t), GFP_ATOMIC);
 547                 if (!discovery) {
 548                         IRDA_WARNING("%s: unable to malloc!\n", __func__);
 549                         return;
 550                 }
 551
 552                 discovery->data.daddr = info->daddr;
 553                 discovery->data.saddr = self->saddr;
 554                 discovery->timestamp = jiffies;
 555
 556                 discovery->data.hints[0] = discovery_info[0];
 557                 if (discovery_info[0] & HINT_EXTENSION) {
 558                         discovery->data.hints[1] = discovery_info[1];
 559                         discovery->data.charset = discovery_info[2];
 560                         text = (char *) &discovery_info[3];
 561                 } else {
 562                         discovery->data.hints[1] = 0;
 563                         discovery->data.charset = discovery_info[1];
 564                         text = (char *) &discovery_info[2];
 565                 }
 566                 /*
 567                  *  Terminate string, should be safe since this is where the
 568                  *  FCS bytes resides.
 569                  */
 570                 skb->data[skb->len] = '\0';
 571                 strncpy(discovery->data.info, text, NICKNAME_MAX_LEN);
 572                 discovery->name_len = strlen(discovery->data.info);
 573
 574                 info->discovery = discovery;
 575         } else
 576                 info->discovery = NULL;
 577
 578         irlap_do_event(self, RECV_DISCOVERY_XID_CMD, skb, info);
 579 }
 580
 581 /*
 582  * Function irlap_send_rr_frame (self, command)
 583  *
 584  *    Build and transmit RR (Receive Ready) frame. Notice that it is currently
 585  *    only possible to send RR frames with the poll bit set.
 586  */
 587 void irlap_send_rr_frame(struct irlap_cb *self, int command)
 588 {
 589         struct sk_buff *tx_skb;
 590         struct rr_frame *frame;
 591
 592         tx_skb = alloc_skb(sizeof(struct rr_frame), GFP_ATOMIC);
 593         if (!tx_skb)
 594                 return;
 595
 596         frame = (struct rr_frame *)skb_put(tx_skb, 2);
 597
 598         frame->caddr = self->caddr;
 599         frame->caddr |= (command) ? CMD_FRAME : 0;
 600
 601         frame->control = RR | PF_BIT | (self->vr << 5);
 602
 603         irlap_queue_xmit(self, tx_skb);
 604 }
 605
 606 /*
 607  * Function irlap_send_rd_frame (self)
 608  *
 609  *    Request disconnect. Used by a secondary station to request the
 610  *    disconnection of the link.
 611  */
 612 void irlap_send_rd_frame(struct irlap_cb *self)
 613 {
 614         struct sk_buff *tx_skb;
 615         struct rd_frame *frame;
 616
 617         tx_skb = alloc_skb(sizeof(struct rd_frame), GFP_ATOMIC);
 618         if (!tx_skb)
 619                 return;
 620
 621         frame = (struct rd_frame *)skb_put(tx_skb, 2);
 622
 623         frame->caddr = self->caddr;
 624         frame->caddr = RD_RSP | PF_BIT;
 625
 626         irlap_queue_xmit(self, tx_skb);
 627 }
 628
 629 /*
 630  * Function irlap_recv_rr_frame (skb, info)
 631  *
 632  *    Received RR (Receive Ready) frame from peer station, no harm in
 633  *    making it inline since its called only from one single place
 634  *    (irlap_driver_rcv).
 635  */
 636 static inline void irlap_recv_rr_frame(struct irlap_cb *self,
 637                                        struct sk_buff *skb,
 638                                        struct irlap_info *info, int command)
 639 {
 640         info->nr = skb->data[1] >> 5;
 641
 642         /* Check if this is a command or a response frame */
 643         if (command)
 644                 irlap_do_event(self, RECV_RR_CMD, skb, info);
 645         else
 646                 irlap_do_event(self, RECV_RR_RSP, skb, info);
 647 }
 648
 649 /*
 650  * Function irlap_recv_rnr_frame (self, skb, info)
 651  *
 652  *    Received RNR (Receive Not Ready) frame from peer station
 653  *
 654  */
 655 static void irlap_recv_rnr_frame(struct irlap_cb *self, struct sk_buff *skb,
 656                                  struct irlap_info *info, int command)
 657 {
 658         info->nr = skb->data[1] >> 5;
 659
 660         IRDA_DEBUG(4, "%s(), nr=%d, %ld\n", __func__, info->nr, jiffies);
 661
 662         if (command)
 663                 irlap_do_event(self, RECV_RNR_CMD, skb, info);
 664         else
 665                 irlap_do_event(self, RECV_RNR_RSP, skb, info);
 666 }
 667
 668 static void irlap_recv_rej_frame(struct irlap_cb *self, struct sk_buff *skb,
 669                                  struct irlap_info *info, int command)
 670 {
 671         IRDA_DEBUG(0, "%s()\n", __func__);
 672
 673         info->nr = skb->data[1] >> 5;
 674
 675         /* Check if this is a command or a response frame */
 676         if (command)
 677                 irlap_do_event(self, RECV_REJ_CMD, skb, info);
 678         else
 679                 irlap_do_event(self, RECV_REJ_RSP, skb, info);
 680 }
 681
 682 static void irlap_recv_srej_frame(struct irlap_cb *self, struct sk_buff *skb,
 683                                   struct irlap_info *info, int command)
 684 {
 685         IRDA_DEBUG(0, "%s()\n", __func__);
 686
 687         info->nr = skb->data[1] >> 5;
 688
 689         /* Check if this is a command or a response frame */
 690         if (command)
 691                 irlap_do_event(self, RECV_SREJ_CMD, skb, info);
 692         else
 693                 irlap_do_event(self, RECV_SREJ_RSP, skb, info);
 694 }
 695
 696 static void irlap_recv_disc_frame(struct irlap_cb *self, struct sk_buff *skb,
 697                                   struct irlap_info *info, int command)
 698 {
 699         IRDA_DEBUG(2, "%s()\n", __func__);
 700
 701         /* Check if this is a command or a response frame */
 702         if (command)
 703                 irlap_do_event(self, RECV_DISC_CMD, skb, info);
 704         else
 705                 irlap_do_event(self, RECV_RD_RSP, skb, info);
 706 }
 707
 708 /*
 709  * Function irlap_recv_ua_frame (skb, frame)
 710  *
 711  *    Received UA (Unnumbered Acknowledgement) frame
 712  *
 713  */
 714 static inline void irlap_recv_ua_frame(struct irlap_cb *self,
 715                                        struct sk_buff *skb,
 716                                        struct irlap_info *info)
 717 {
 718         irlap_do_event(self, RECV_UA_RSP, skb, info);
 719 }
 720
 721 /*
 722  * Function irlap_send_data_primary(self, skb)
 723  *
 724  *    Send I-frames as the primary station but without the poll bit set
 725  *
 726  */
 727 void irlap_send_data_primary(struct irlap_cb *self, struct sk_buff *skb)
 728 {
 729         struct sk_buff *tx_skb;
 730
 731         if (skb->data[1] == I_FRAME) {
 732
 733                 /*
 734                  *  Insert frame sequence number (Vs) in control field before
 735                  *  inserting into transmit window queue.
 736                  */
 737                 skb->data[1] = I_FRAME | (self->vs << 1);
 738
 739                 /*
 740                  *  Insert frame in store, in case of retransmissions
 741                  *  Increase skb reference count, see irlap_do_event()
 742                  */
 743                 skb_get(skb);
 744                 skb_queue_tail(&self->wx_list, skb);
 745
 746                 /* Copy buffer */
 747                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 748                 if (tx_skb == NULL) {
 749                         return;
 750                 }
 751
 752                 self->vs = (self->vs + 1) % 8;
 753                 self->ack_required = FALSE;
 754                 self->window -= 1;
 755
 756                 irlap_send_i_frame( self, tx_skb, CMD_FRAME);
 757         } else {
 758                 IRDA_DEBUG(4, "%s(), sending unreliable frame\n", __func__);
 759                 irlap_send_ui_frame(self, skb_get(skb), self->caddr, CMD_FRAME);
 760                 self->window -= 1;
 761         }
 762 }
 763 /*
 764  * Function irlap_send_data_primary_poll (self, skb)
 765  *
 766  *    Send I(nformation) frame as primary with poll bit set
 767  */
 768 void irlap_send_data_primary_poll(struct irlap_cb *self, struct sk_buff *skb)
 769 {
 770         struct sk_buff *tx_skb;
 771         int transmission_time;
 772
 773         /* Stop P timer */
 774         del_timer(&self->poll_timer);
 775
 776         /* Is this reliable or unreliable data? */
 777         if (skb->data[1] == I_FRAME) {
 778
 779                 /*
 780                  *  Insert frame sequence number (Vs) in control field before
 781                  *  inserting into transmit window queue.
 782                  */
 783                 skb->data[1] = I_FRAME | (self->vs << 1);
 784
 785                 /*
 786                  *  Insert frame in store, in case of retransmissions
 787                  *  Increase skb reference count, see irlap_do_event()
 788                  */
 789                 skb_get(skb);
 790                 skb_queue_tail(&self->wx_list, skb);
 791
 792                 /* Copy buffer */
 793                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 794                 if (tx_skb == NULL) {
 795                         return;
 796                 }
 797
 798                 /*
 799                  *  Set poll bit if necessary. We do this to the copied
 800                  *  skb, since retransmitted need to set or clear the poll
 801                  *  bit depending on when they are sent.
 802                  */
 803                 tx_skb->data[1] |= PF_BIT;
 804
 805                 self->vs = (self->vs + 1) % 8;
 806                 self->ack_required = FALSE;
 807
 808                 irlap_next_state(self, LAP_NRM_P);
 809                 irlap_send_i_frame(self, tx_skb, CMD_FRAME);
 810         } else {
 811                 IRDA_DEBUG(4, "%s(), sending unreliable frame\n", __func__);
 812
 813                 if (self->ack_required) {
 814                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, CMD_FRAME);
 815                         irlap_next_state(self, LAP_NRM_P);
 816                         irlap_send_rr_frame(self, CMD_FRAME);
 817                         self->ack_required = FALSE;
 818                 } else {
 819                         skb->data[1] |= PF_BIT;
 820                         irlap_next_state(self, LAP_NRM_P);
 821                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, CMD_FRAME);
 822                 }
 823         }
 824
 825         /* How much time we took for transmission of all frames.
 826          * We don't know, so let assume we used the full window. Jean II */
 827         transmission_time = self->final_timeout;
 828
 829         /* Reset parameter so that we can fill next window */
 830         self->window = self->window_size;
 831
 832 #ifdef CONFIG_IRDA_DYNAMIC_WINDOW
 833         /* Remove what we have not used. Just do a prorata of the
 834          * bytes left in window to window capacity.
 835          * See max_line_capacities[][] in qos.c for details. Jean II */
 836         transmission_time -= (self->final_timeout * self->bytes_left
 837                               / self->line_capacity);
 838         IRDA_DEBUG(4, "%s() adjusting transmission_time : ft=%d, bl=%d, lc=%d -> tt=%d\n", __func__, self->final_timeout, self->bytes_left, self->line_capacity, transmission_time);
 839
 840         /* We are allowed to transmit a maximum number of bytes again. */
 841         self->bytes_left = self->line_capacity;
 842 #endif /* CONFIG_IRDA_DYNAMIC_WINDOW */
 843
 844         /*
 845          * The network layer has a intermediate buffer between IrLAP
 846          * and the IrDA driver which can contain 8 frames. So, even
 847          * though IrLAP is currently sending the *last* frame of the
 848          * tx-window, the driver most likely has only just started
 849          * sending the *first* frame of the same tx-window.
 850          * I.e. we are always at the very begining of or Tx window.
 851          * Now, we are supposed to set the final timer from the end
 852          * of our tx-window to let the other peer reply. So, we need
 853          * to add extra time to compensate for the fact that we
 854          * are really at the start of tx-window, otherwise the final timer
 855          * might expire before he can answer...
 856          * Jean II
 857          */
 858         irlap_start_final_timer(self, self->final_timeout + transmission_time);
 859
 860         /*
 861          * The clever amongst you might ask why we do this adjustement
 862          * only here, and not in all the other cases in irlap_event.c.
 863          * In all those other case, we only send a very short management
 864          * frame (few bytes), so the adjustement would be lost in the
 865          * noise...
 866          * The exception of course is irlap_resend_rejected_frame().
 867          * Jean II */
 868 }
 869
 870 /*
 871  * Function irlap_send_data_secondary_final (self, skb)
 872  *
 873  *    Send I(nformation) frame as secondary with final bit set
 874  *
 875  */
 876 void irlap_send_data_secondary_final(struct irlap_cb *self,
 877                                      struct sk_buff *skb)
 878 {
 879         struct sk_buff *tx_skb = NULL;
 880
 881         IRDA_ASSERT(self != NULL, return;);
 882         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 883         IRDA_ASSERT(skb != NULL, return;);
 884
 885         /* Is this reliable or unreliable data? */
 886         if (skb->data[1] == I_FRAME) {
 887
 888                 /*
 889                  *  Insert frame sequence number (Vs) in control field before
 890                  *  inserting into transmit window queue.
 891                  */
 892                 skb->data[1] = I_FRAME | (self->vs << 1);
 893
 894                 /*
 895                  *  Insert frame in store, in case of retransmissions
 896                  *  Increase skb reference count, see irlap_do_event()
 897                  */
 898                 skb_get(skb);
 899                 skb_queue_tail(&self->wx_list, skb);
 900
 901                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 902                 if (tx_skb == NULL) {
 903                         return;
 904                 }
 905
 906                 tx_skb->data[1] |= PF_BIT;
 907
 908                 self->vs = (self->vs + 1) % 8;
 909                 self->ack_required = FALSE;
 910
 911                 irlap_send_i_frame(self, tx_skb, RSP_FRAME);
 912         } else {
 913                 if (self->ack_required) {
 914                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, RSP_FRAME);
 915                         irlap_send_rr_frame(self, RSP_FRAME);
 916                         self->ack_required = FALSE;
 917                 } else {
 918                         skb->data[1] |= PF_BIT;
 919                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, RSP_FRAME);
 920                 }
 921         }
 922
 923         self->window = self->window_size;
 924 #ifdef CONFIG_IRDA_DYNAMIC_WINDOW
 925         /* We are allowed to transmit a maximum number of bytes again. */
 926         self->bytes_left = self->line_capacity;
 927 #endif /* CONFIG_IRDA_DYNAMIC_WINDOW */
 928
 929         irlap_start_wd_timer(self, self->wd_timeout);
 930 }
 931
 932 /*
 933  * Function irlap_send_data_secondary (self, skb)
 934  *
 935  *    Send I(nformation) frame as secondary without final bit set
 936  *
 937  */
 938 void irlap_send_data_secondary(struct irlap_cb *self, struct sk_buff *skb)
 939 {
 940         struct sk_buff *tx_skb = NULL;
 941
 942         /* Is this reliable or unreliable data? */
 943         if (skb->data[1] == I_FRAME) {
 944
 945                 /*
 946                  *  Insert frame sequence number (Vs) in control field before
 947                  *  inserting into transmit window queue.
 948                  */
 949                 skb->data[1] = I_FRAME | (self->vs << 1);
 950
 951                 /*
 952                  *  Insert frame in store, in case of retransmissions
 953                  *  Increase skb reference count, see irlap_do_event()
 954                  */
 955                 skb_get(skb);
 956                 skb_queue_tail(&self->wx_list, skb);
 957
 958                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 959                 if (tx_skb == NULL) {
 960                         return;
 961                 }
 962
 963                 self->vs = (self->vs + 1) % 8;
 964                 self->ack_required = FALSE;
 965                 self->window -= 1;
 966
 967                 irlap_send_i_frame(self, tx_skb, RSP_FRAME);
 968         } else {
 969                 irlap_send_ui_frame(self, skb_get(skb), self->caddr, RSP_FRAME);
 970                 self->window -= 1;
 971         }
 972 }
 973
 974 /*
 975  * Function irlap_resend_rejected_frames (nr)
 976  *
 977  *    Resend frames which has not been acknowledged. Should be safe to
 978  *    traverse the list without locking it since this function will only be
 979  *    called from interrupt context (BH)
 980  */
 981 void irlap_resend_rejected_frames(struct irlap_cb *self, int command)
 982 {
 983         struct sk_buff *tx_skb;
 984         struct sk_buff *skb;
 985         int count;
 986
 987         IRDA_ASSERT(self != NULL, return;);
 988         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 989
 990         /* Initialize variables */
 991         count = skb_queue_len(&self->wx_list);
 992
 993         /*  Resend unacknowledged frame(s) */
 994         skb = skb_peek(&self->wx_list);
 995         while (skb != NULL) {
 996                 irlap_wait_min_turn_around(self, &self->qos_tx);
 997
 998                 /* We copy the skb to be retransmitted since we will have to
 999                  * modify it. Cloning will confuse packet sniffers
1000                  */
1001                 /* tx_skb = skb_clone( skb, GFP_ATOMIC); */
1002                 tx_skb = skb_copy(skb, GFP_ATOMIC);
1003                 if (!tx_skb) {
1004                         IRDA_DEBUG(0, "%s(), unable to copy\n", __func__);
1005                         return;
1006                 }
1007
1008                 /* Clear old Nr field + poll bit */
1009                 tx_skb->data[1] &= 0x0f;
1010
1011                 /*
1012                  *  Set poll bit on the last frame retransmitted
1013                  */
1014                 if (count-- == 1)
1015                         tx_skb->data[1] |= PF_BIT; /* Set p/f bit */
1016                 else
1017                         tx_skb->data[1] &= ~PF_BIT; /* Clear p/f bit */
1018
1019                 irlap_send_i_frame(self, tx_skb, command);
1020
1021                 /*
1022                  *  If our skb is the last buffer in the list, then
1023                  *  we are finished, if not, move to the next sk-buffer
1024                  */
1025                 if (skb == skb_peek_tail(&self->wx_list))
1026                         skb = NULL;
1027                 else
1028                         skb = skb->next;
1029         }
1030 #if 0 /* Not yet */
1031         /*
1032          *  We can now fill the window with additional data frames
1033          */
1034         while (!skb_queue_empty(&self->txq)) {
1035
1036                 IRDA_DEBUG(0, "%s(), sending additional frames!\n", __func__);
1037                 if (self->window > 0) {
1038                         skb = skb_dequeue( &self->txq);
1039                         IRDA_ASSERT(skb != NULL, return;);
1040
1041                         /*
1042                          *  If send window > 1 then send frame with pf
1043                          *  bit cleared
1044                          */
1045                         if ((self->window > 1) &&
1046                             !skb_queue_empty(&self->txq)) {
1047                                 irlap_send_data_primary(self, skb);
1048                         } else {
1049                                 irlap_send_data_primary_poll(self, skb);
1050                         }
1051                         kfree_skb(skb);
1052                 }
1053         }
1054 #endif
1055 }
1056
1057 void irlap_resend_rejected_frame(struct irlap_cb *self, int command)
1058 {
1059         struct sk_buff *tx_skb;
1060         struct sk_buff *skb;
1061
1062         IRDA_ASSERT(self != NULL, return;);
1063         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
1064
1065         /*  Resend unacknowledged frame(s) */
1066         skb = skb_peek(&self->wx_list);
1067         if (skb != NULL) {
1068                 irlap_wait_min_turn_around(self, &self->qos_tx);
1069
1070                 /* We copy the skb to be retransmitted since we will have to
1071                  * modify it. Cloning will confuse packet sniffers
1072                  */
1073                 /* tx_skb = skb_clone( skb, GFP_ATOMIC); */
1074                 tx_skb = skb_copy(skb, GFP_ATOMIC);
1075                 if (!tx_skb) {
1076                         IRDA_DEBUG(0, "%s(), unable to copy\n", __func__);
1077                         return;
1078                 }
1079
1080                 /* Clear old Nr field + poll bit */
1081                 tx_skb->data[1] &= 0x0f;
1082
1083                 /*  Set poll/final bit */
1084                 tx_skb->data[1] |= PF_BIT; /* Set p/f bit */
1085
1086                 irlap_send_i_frame(self, tx_skb, command);
1087         }
1088 }
1089
1090 /*
1091  * Function irlap_send_ui_frame (self, skb, command)
1092  *
1093  *    Contruct and transmit an Unnumbered Information (UI) frame
1094  *
1095  */
1096 void irlap_send_ui_frame(struct irlap_cb *self, struct sk_buff *skb,
1097                          __u8 caddr, int command)
1098 {
1099         IRDA_DEBUG(4, "%s()\n", __func__);
1100
1101         IRDA_ASSERT(self != NULL, return;);
1102         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
1103         IRDA_ASSERT(skb != NULL, return;);
1104
1105         /* Insert connection address */
1106         skb->data[0] = caddr | ((command) ? CMD_FRAME : 0);
1107
1108         irlap_queue_xmit(self, skb);
1109 }
1110
1111 /*
1112  * Function irlap_send_i_frame (skb)
1113  *
1114  *    Contruct and transmit Information (I) frame
1115  */
1116 static void irlap_send_i_frame(struct irlap_cb *self, struct sk_buff *skb,
1117                                int command)
1118 {
1119         /* Insert connection address */
1120         skb->data[0] = self->caddr;
1121         skb->data[0] |= (command) ? CMD_FRAME : 0;
1122
1123         /* Insert next to receive (Vr) */
1124         skb->data[1] |= (self->vr << 5);  /* insert nr */
1125
1126         irlap_queue_xmit(self, skb);
1127 }
1128
1129 /*
1130  * Function irlap_recv_i_frame (skb, frame)
1131  *
1132  *    Receive and parse an I (Information) frame, no harm in making it inline
1133  *    since it's called only from one single place (irlap_driver_rcv).
1134  */
1135 static inline void irlap_recv_i_frame(struct irlap_cb *self,
1136                                       struct sk_buff *skb,
1137                                       struct irlap_info *info, int command)
1138 {
1139         info->nr = skb->data[1] >> 5;          /* Next to receive */
1140         info->pf = skb->data[1] & PF_BIT;      /* Final bit */
1141         info->ns = (skb->data[1] >> 1) & 0x07; /* Next to send */
1142
1143         /* Check if this is a command or a response frame */
1144         if (command)
1145                 irlap_do_event(self, RECV_I_CMD, skb, info);
1146         else
1147                 irlap_do_event(self, RECV_I_RSP, skb, info);
1148 }
1149
1150 /*
1151  * Function irlap_recv_ui_frame (self, skb, info)
1152  *
1153  *    Receive and parse an Unnumbered Information (UI) frame
1154  *
1155  */
1156 static void irlap_recv_ui_frame(struct irlap_cb *self, struct sk_buff *skb,
1157                                 struct irlap_info *info)
1158 {
1159         IRDA_DEBUG( 4, "%s()\n", __func__);
1160
1161         info->pf = skb->data[1] & PF_BIT;      /* Final bit */
1162
1163         irlap_do_event(self, RECV_UI_FRAME, skb, info);
1164 }
1165
1166 /*
1167  * Function irlap_recv_frmr_frame (skb, frame)
1168  *
1169  *    Received Frame Reject response.
1170  *
1171  */
1172 static void irlap_recv_frmr_frame(struct irlap_cb *self, struct sk_buff *skb,
1173                                   struct irlap_info *info)
1174 {
1175         __u8 *frame;
1176         int w, x, y, z;
1177
1178         IRDA_DEBUG(0, "%s()\n", __func__);
1179
1180         IRDA_ASSERT(self != NULL, return;);
1181         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
1182         IRDA_ASSERT(skb != NULL, return;);
1183         IRDA_ASSERT(info != NULL, return;);
1184
1185         if (!pskb_may_pull(skb, 4)) {
1186                 IRDA_ERROR("%s: frame too short!\n", __func__);
1187                 return;
1188         }
1189
1190         frame = skb->data;
1191
1192         info->nr = frame[2] >> 5;          /* Next to receive */
1193         info->pf = frame[2] & PF_BIT;      /* Final bit */
1194         info->ns = (frame[2] >> 1) & 0x07; /* Next to send */
1195
1196         w = frame[3] & 0x01;
1197         x = frame[3] & 0x02;
1198         y = frame[3] & 0x04;
1199         z = frame[3] & 0x08;
1200
1201         if (w) {
1202                 IRDA_DEBUG(0, "Rejected control field is undefined or not "
1203                       "implemented.\n");
1204         }
1205         if (x) {
1206                 IRDA_DEBUG(0, "Rejected control field was invalid because it "
1207                       "contained a non permitted I field.\n");
1208         }
1209         if (y) {
1210                 IRDA_DEBUG(0, "Received I field exceeded the maximum negotiated "
1211                       "for the existing connection or exceeded the maximum "
1212                       "this station supports if no connection exists.\n");
1213         }
1214         if (z) {
1215                 IRDA_DEBUG(0, "Rejected control field control field contained an "
1216                       "invalid Nr count.\n");
1217         }
1218         irlap_do_event(self, RECV_FRMR_RSP, skb, info);
1219 }
1220
1221 /*
1222  * Function irlap_send_test_frame (self, daddr)
1223  *
1224  *    Send a test frame response
1225  *
1226  */
1227 void irlap_send_test_frame(struct irlap_cb *self, __u8 caddr, __u32 daddr,
1228                            struct sk_buff *cmd)
1229 {
1230         struct sk_buff *tx_skb;
1231         struct test_frame *frame;
1232         __u8 *info;
1233
1234         tx_skb = alloc_skb(cmd->len + sizeof(struct test_frame), GFP_ATOMIC);
1235         if (!tx_skb)
1236                 return;
1237
1238         /* Broadcast frames must include saddr and daddr fields */
1239         if (caddr == CBROADCAST) {
1240                 frame = (struct test_frame *)
1241                         skb_put(tx_skb, sizeof(struct test_frame));
1242
1243                 /* Insert the swapped addresses */
1244                 frame->saddr = cpu_to_le32(self->saddr);
1245                 frame->daddr = cpu_to_le32(daddr);
1246         } else
1247                 frame = (struct test_frame *) skb_put(tx_skb, LAP_ADDR_HEADER + LAP_CTRL_HEADER);
1248
1249         frame->caddr = caddr;
1250         frame->control = TEST_RSP | PF_BIT;
1251
1252         /* Copy info */
1253         info = skb_put(tx_skb, cmd->len);
1254         memcpy(info, cmd->data, cmd->len);
1255
1256         /* Return to sender */
1257         irlap_wait_min_turn_around(self, &self->qos_tx);
1258         irlap_queue_xmit(self, tx_skb);
1259 }
1260
1261 /*
1262  * Function irlap_recv_test_frame (self, skb)
1263  *
1264  *    Receive a test frame
1265  *
1266  */
1267 static void irlap_recv_test_frame(struct irlap_cb *self, struct sk_buff *skb,
1268                                   struct irlap_info *info, int command)
1269 {
1270         struct test_frame *frame;
1271
1272         IRDA_DEBUG(2, "%s()\n", __func__);
1273
1274         if (!pskb_may_pull(skb, sizeof(*frame))) {
1275                 IRDA_ERROR("%s: frame too short!\n", __func__);
1276                 return;
1277         }
1278         frame = (struct test_frame *) skb->data;
1279
1280         /* Broadcast frames must carry saddr and daddr fields */
1281         if (info->caddr == CBROADCAST) {
1282                 if (skb->len < sizeof(struct test_frame)) {
1283                         IRDA_DEBUG(0, "%s() test frame too short!\n",
1284                                    __func__);
1285                         return;
1286                 }
1287
1288                 /* Read and swap addresses */
1289                 info->daddr = le32_to_cpu(frame->saddr);
1290                 info->saddr = le32_to_cpu(frame->daddr);
1291
1292                 /* Make sure frame is addressed to us */
1293                 if ((info->saddr != self->saddr) &&
1294                     (info->saddr != BROADCAST)) {
1295                         return;
1296                 }
1297         }
1298
1299         if (command)
1300                 irlap_do_event(self, RECV_TEST_CMD, skb, info);
1301         else
1302                 irlap_do_event(self, RECV_TEST_RSP, skb, info);
1303 }
1304
1305 /*
1306  * Function irlap_driver_rcv (skb, netdev, ptype)
1307  *
1308  *    Called when a frame is received. Dispatches the right receive function
1309  *    for processing of the frame.
1310  *
1311  * Note on skb management :
1312  * After calling the higher layers of the IrDA stack, we always
1313  * kfree() the skb, which drop the reference count (and potentially
1314  * destroy it).
1315  * If a higher layer of the stack want to keep the skb around (to put
1316  * in a queue or pass it to the higher layer), it will need to use
1317  * skb_get() to keep a reference on it. This is usually done at the
1318  * LMP level in irlmp.c.
1319  * Jean II
1320  */
1321 int irlap_driver_rcv(struct sk_buff *skb, struct net_device *dev,
1322                      struct packet_type *ptype, struct net_device *orig_dev)
1323 {
1324         struct irlap_info info;
1325         struct irlap_cb *self;
1326         int command;
1327         __u8 control;
1328
1329         if (dev_net(dev) != &init_net)
1330                 goto out;
1331
1332         /* FIXME: should we get our own field? */
1333         self = (struct irlap_cb *) dev->atalk_ptr;
1334
1335         /* If the net device is down, then IrLAP is gone! */
1336         if (!self || self->magic != LAP_MAGIC) {
1337                 dev_kfree_skb(skb);
1338                 return -1;
1339         }
1340
1341         /* We are no longer an "old" protocol, so we need to handle
1342          * share and non linear skbs. This should never happen, so
1343          * we don't need to be clever about it. Jean II */
1344         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
1345                 IRDA_ERROR("%s: can't clone shared skb!\n", __func__);
1346                 dev_kfree_skb(skb);
1347                 return -1;
1348         }
1349
1350         /* Check if frame is large enough for parsing */
1351         if (!pskb_may_pull(skb, 2)) {
1352                 IRDA_ERROR("%s: frame too short!\n", __func__);
1353                 dev_kfree_skb(skb);
1354                 return -1;
1355         }
1356
1357         command    = skb->data[0] & CMD_FRAME;
1358         info.caddr = skb->data[0] & CBROADCAST;
1359
1360         info.pf      = skb->data[1] &  PF_BIT;
1361         info.control = skb->data[1] & ~PF_BIT; /* Mask away poll/final bit */
1362
1363         control = info.control;
1364
1365         /*  First we check if this frame has a valid connection address */
1366         if ((info.caddr != self->caddr) && (info.caddr != CBROADCAST)) {
1367                 IRDA_DEBUG(0, "%s(), wrong connection address!\n",
1368                            __func__);
1369                 goto out;
1370         }
1371         /*
1372          *  Optimize for the common case and check if the frame is an
1373          *  I(nformation) frame. Only I-frames have bit 0 set to 0
1374          */
1375         if (~control & 0x01) {
1376                 irlap_recv_i_frame(self, skb, &info, command);
1377                 goto out;
1378         }
1379         /*
1380          *  We now check is the frame is an S(upervisory) frame. Only
1381          *  S-frames have bit 0 set to 1 and bit 1 set to 0
1382          */
1383         if (~control & 0x02) {
1384                 /*
1385                  *  Received S(upervisory) frame, check which frame type it is
1386                  *  only the first nibble is of interest
1387                  */
1388                 switch (control & 0x0f) {
1389                 case RR:
1390                         irlap_recv_rr_frame(self, skb, &info, command);
1391                         break;
1392                 case RNR:
1393                         irlap_recv_rnr_frame(self, skb, &info, command);
1394                         break;
1395                 case REJ:
1396                         irlap_recv_rej_frame(self, skb, &info, command);
1397                         break;
1398                 case SREJ:
1399                         irlap_recv_srej_frame(self, skb, &info, command);
1400                         break;
1401                 default:
1402                         IRDA_WARNING("%s: Unknown S-frame %02x received!\n",
1403                                 __func__, info.control);
1404                         break;
1405                 }
1406                 goto out;
1407         }
1408         /*
1409          *  This must be a C(ontrol) frame
1410          */
1411         switch (control) {
1412         case XID_RSP:
1413                 irlap_recv_discovery_xid_rsp(self, skb, &info);
1414                 break;
1415         case XID_CMD:
1416                 irlap_recv_discovery_xid_cmd(self, skb, &info);
1417                 break;
1418         case SNRM_CMD:
1419                 irlap_recv_snrm_cmd(self, skb, &info);
1420                 break;
1421         case DM_RSP:
1422                 irlap_do_event(self, RECV_DM_RSP, skb, &info);
1423                 break;
1424         case DISC_CMD: /* And RD_RSP since they have the same value */
1425                 irlap_recv_disc_frame(self, skb, &info, command);
1426                 break;
1427         case TEST_CMD:
1428                 irlap_recv_test_frame(self, skb, &info, command);
1429                 break;
1430         case UA_RSP:
1431                 irlap_recv_ua_frame(self, skb, &info);
1432                 break;
1433         case FRMR_RSP:
1434                 irlap_recv_frmr_frame(self, skb, &info);
1435                 break;
1436         case UI_FRAME:
1437                 irlap_recv_ui_frame(self, skb, &info);
1438                 break;
1439         default:
1440                 IRDA_WARNING("%s: Unknown frame %02x received!\n",
1441                                 __func__, info.control);
1442                 break;
1443         }
1444 out:
1445         /* Always drop our reference on the skb */
1446         dev_kfree_skb(skb);
1447         return 0;
1448 }