drivers/net/arcnet/rfc1201.c

   1 /*
   2  * Linux ARCnet driver - RFC1201 (standard) packet encapsulation
   3  *
   4  * Written 1994-1999 by Avery Pennarun.
   5  * Derived from skeleton.c by Donald Becker.
   6  *
   7  * Special thanks to Contemporary Controls, Inc. (www.ccontrols.com)
   8  *  for sponsoring the further development of this driver.
   9  *
  10  * **********************
  11  *
  12  * The original copyright of skeleton.c was as follows:
  13  *
  14  * skeleton.c Written 1993 by Donald Becker.
  15  * Copyright 1993 United States Government as represented by the
  16  * Director, National Security Agency.  This software may only be used
  17  * and distributed according to the terms of the GNU General Public License as
  18  * modified by SRC, incorporated herein by reference.
  19  *
  20  * **********************
  21  *
  22  * For more details, see drivers/net/arcnet.c
  23  *
  24  * **********************
  25  */
  26 #include <linux/module.h>
  27 #include <linux/init.h>
  28 #include <linux/if_arp.h>
  29 #include <linux/netdevice.h>
  30 #include <linux/skbuff.h>
  31 #include <linux/arcdevice.h>
  32
  33 MODULE_LICENSE("GPL");
  34 #define VERSION "arcnet: RFC1201 \"standard\" (`a') encapsulation support loaded.\n"
  35
  36
  37 static unsigned short type_trans(struct sk_buff *skb, struct net_device *dev);
  38 static void rx(struct net_device *dev, int bufnum,
  39                struct archdr *pkthdr, int length);
  40 static int build_header(struct sk_buff *skb, struct net_device *dev,
  41                         unsigned short type, uint8_t daddr);
  42 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
  43                       int bufnum);
  44 static int continue_tx(struct net_device *dev, int bufnum);
  45
  46 struct ArcProto rfc1201_proto =
  47 {
  48         .suffix         = 'a',
  49         .mtu            = 1500, /* could be more, but some receivers can't handle it... */
  50         .rx             = rx,
  51         .build_header   = build_header,
  52         .prepare_tx     = prepare_tx,
  53         .continue_tx    = continue_tx,
  54 };
  55
  56
  57 static int __init arcnet_rfc1201_init(void)
  58 {
  59         printk(VERSION);
  60
  61         arc_proto_map[ARC_P_IP]
  62             = arc_proto_map[ARC_P_IPV6]
  63             = arc_proto_map[ARC_P_ARP]
  64             = arc_proto_map[ARC_P_RARP]
  65             = arc_proto_map[ARC_P_IPX]
  66             = arc_proto_map[ARC_P_NOVELL_EC]
  67             = &rfc1201_proto;
  68
  69         /* if someone else already owns the broadcast, we won't take it */
  70         if (arc_bcast_proto == arc_proto_default)
  71                 arc_bcast_proto = &rfc1201_proto;
  72
  73         return 0;
  74 }
  75
  76 static void __exit arcnet_rfc1201_exit(void)
  77 {
  78         arcnet_unregister_proto(&rfc1201_proto);
  79 }
  80
  81 module_init(arcnet_rfc1201_init);
  82 module_exit(arcnet_rfc1201_exit);
  83
  84 /*
  85  * Determine a packet's protocol ID.
  86  *
  87  * With ARCnet we have to convert everything to Ethernet-style stuff.
  88  */
  89 static unsigned short type_trans(struct sk_buff *skb, struct net_device *dev)
  90 {
  91         struct archdr *pkt = (struct archdr *) skb->data;
  92         struct arc_rfc1201 *soft = &pkt->soft.rfc1201;
  93         struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
  94         int hdr_size = ARC_HDR_SIZE + RFC1201_HDR_SIZE;
  95
  96         /* Pull off the arcnet header. */
  97         skb->mac.raw = skb->data;
  98         skb_pull(skb, hdr_size);
  99
 100         if (pkt->hard.dest == 0)
 101                 skb->pkt_type = PACKET_BROADCAST;
 102         else if (dev->flags & IFF_PROMISC) {
 103                 /* if we're not sending to ourselves :) */
 104                 if (pkt->hard.dest != dev->dev_addr[0])
 105                         skb->pkt_type = PACKET_OTHERHOST;
 106         }
 107         /* now return the protocol number */
 108         switch (soft->proto) {
 109         case ARC_P_IP:
 110                 return htons(ETH_P_IP);
 111         case ARC_P_IPV6:
 112                 return htons(ETH_P_IPV6);
 113         case ARC_P_ARP:
 114                 return htons(ETH_P_ARP);
 115         case ARC_P_RARP:
 116                 return htons(ETH_P_RARP);
 117
 118         case ARC_P_IPX:
 119         case ARC_P_NOVELL_EC:
 120                 return htons(ETH_P_802_3);
 121         default:
 122                 lp->stats.rx_errors++;
 123                 lp->stats.rx_crc_errors++;
 124                 return 0;
 125         }
 126
 127         return htons(ETH_P_IP);
 128 }
 129
 130
 131 /* packet receiver */
 132 static void rx(struct net_device *dev, int bufnum,
 133                struct archdr *pkthdr, int length)
 134 {
 135         struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
 136         struct sk_buff *skb;
 137         struct archdr *pkt = pkthdr;
 138         struct arc_rfc1201 *soft = &pkthdr->soft.rfc1201;
 139         int saddr = pkt->hard.source, ofs;
 140         struct Incoming *in = &lp->rfc1201.incoming[saddr];
 141
 142         BUGMSG(D_DURING, "it's an RFC1201 packet (length=%d)\n", length);
 143
 144         if (length >= MinTU)
 145                 ofs = 512 - length;
 146         else
 147                 ofs = 256 - length;
 148
 149         if (soft->split_flag == 0xFF) {         /* Exception Packet */
 150                 if (length >= 4 + RFC1201_HDR_SIZE)
 151                         BUGMSG(D_DURING, "compensating for exception packet\n");
 152                 else {
 153                         BUGMSG(D_EXTRA, "short RFC1201 exception packet from %02Xh",
 154                                saddr);
 155                         return;
 156                 }
 157
 158                 /* skip over 4-byte junkola */
 159                 length -= 4;
 160                 ofs += 4;
 161                 lp->hw.copy_from_card(dev, bufnum, 512 - length,
 162                                       soft, sizeof(pkt->soft));
 163         }
 164         if (!soft->split_flag) {        /* not split */
 165                 BUGMSG(D_RX, "incoming is not split (splitflag=%d)\n",
 166                        soft->split_flag);
 167
 168                 if (in->skb) {  /* already assembling one! */
 169                         BUGMSG(D_EXTRA, "aborting assembly (seq=%d) for unsplit packet (splitflag=%d, seq=%d)\n",
 170                          in->sequence, soft->split_flag, soft->sequence);
 171                         lp->rfc1201.aborted_seq = soft->sequence;
 172                         dev_kfree_skb_irq(in->skb);
 173                         lp->stats.rx_errors++;
 174                         lp->stats.rx_missed_errors++;
 175                         in->skb = NULL;
 176                 }
 177                 in->sequence = soft->sequence;
 178
 179                 skb = alloc_skb(length + ARC_HDR_SIZE, GFP_ATOMIC);
 180                 if (skb == NULL) {
 181                         BUGMSG(D_NORMAL, "Memory squeeze, dropping packet.\n");
 182                         lp->stats.rx_dropped++;
 183                         return;
 184                 }
 185                 skb_put(skb, length + ARC_HDR_SIZE);
 186                 skb->dev = dev;
 187
 188                 pkt = (struct archdr *) skb->data;
 189                 soft = &pkt->soft.rfc1201;
 190
 191                 /* up to sizeof(pkt->soft) has already been copied from the card */
 192                 memcpy(pkt, pkthdr, sizeof(struct archdr));
 193                 if (length > sizeof(pkt->soft))
 194                         lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft),
 195                                        pkt->soft.raw + sizeof(pkt->soft),
 196                                               length - sizeof(pkt->soft));
 197
 198                 /*
 199                  * ARP packets have problems when sent from some DOS systems: the
 200                  * source address is always 0!  So we take the hardware source addr
 201                  * (which is impossible to fumble) and insert it ourselves.
 202                  */
 203                 if (soft->proto == ARC_P_ARP) {
 204                         struct arphdr *arp = (struct arphdr *) soft->payload;
 205
 206                         /* make sure addresses are the right length */
 207                         if (arp->ar_hln == 1 && arp->ar_pln == 4) {
 208                                 uint8_t *cptr = (uint8_t *) arp + sizeof(struct arphdr);
 209
 210                                 if (!*cptr) {   /* is saddr = 00? */
 211                                         BUGMSG(D_EXTRA,
 212                                                "ARP source address was 00h, set to %02Xh.\n",
 213                                                saddr);
 214                                         lp->stats.rx_crc_errors++;
 215                                         *cptr = saddr;
 216                                 } else {
 217                                         BUGMSG(D_DURING, "ARP source address (%Xh) is fine.\n",
 218                                                *cptr);
 219                                 }
 220                         } else {
 221                                 BUGMSG(D_NORMAL, "funny-shaped ARP packet. (%Xh, %Xh)\n",
 222                                        arp->ar_hln, arp->ar_pln);
 223                                 lp->stats.rx_errors++;
 224                                 lp->stats.rx_crc_errors++;
 225                         }
 226                 }
 227                 BUGLVL(D_SKB) arcnet_dump_skb(dev, skb, "rx");
 228
 229                 skb->protocol = type_trans(skb, dev);
 230                 netif_rx(skb);
 231                 dev->last_rx = jiffies;
 232         } else {                /* split packet */
 233                 /*
 234                  * NOTE: MSDOS ARP packet correction should only need to apply to
 235                  * unsplit packets, since ARP packets are so short.
 236                  *
 237                  * My interpretation of the RFC1201 document is that if a packet is
 238                  * received out of order, the entire assembly process should be
 239                  * aborted.
 240                  *
 241                  * The RFC also mentions "it is possible for successfully received
 242                  * packets to be retransmitted." As of 0.40 all previously received
 243                  * packets are allowed, not just the most recent one.
 244                  *
 245                  * We allow multiple assembly processes, one for each ARCnet card
 246                  * possible on the network.  Seems rather like a waste of memory,
 247                  * but there's no other way to be reliable.
 248                  */
 249
 250                 BUGMSG(D_RX, "packet is split (splitflag=%d, seq=%d)\n",
 251                        soft->split_flag, in->sequence);
 252
 253                 if (in->skb && in->sequence != soft->sequence) {
 254                         BUGMSG(D_EXTRA, "wrong seq number (saddr=%d, expected=%d, seq=%d, splitflag=%d)\n",
 255                                saddr, in->sequence, soft->sequence,
 256                                soft->split_flag);
 257                         dev_kfree_skb_irq(in->skb);
 258                         in->skb = NULL;
 259                         lp->stats.rx_errors++;
 260                         lp->stats.rx_missed_errors++;
 261                         in->lastpacket = in->numpackets = 0;
 262                 }
 263                 if (soft->split_flag & 1) {     /* first packet in split */
 264                         BUGMSG(D_RX, "brand new splitpacket (splitflag=%d)\n",
 265                                soft->split_flag);
 266                         if (in->skb) {  /* already assembling one! */
 267                                 BUGMSG(D_EXTRA, "aborting previous (seq=%d) assembly "
 268                                        "(splitflag=%d, seq=%d)\n",
 269                                        in->sequence, soft->split_flag,
 270                                        soft->sequence);
 271                                 lp->stats.rx_errors++;
 272                                 lp->stats.rx_missed_errors++;
 273                                 dev_kfree_skb_irq(in->skb);
 274                         }
 275                         in->sequence = soft->sequence;
 276                         in->numpackets = ((unsigned) soft->split_flag >> 1) + 2;
 277                         in->lastpacket = 1;
 278
 279                         if (in->numpackets > 16) {
 280                                 BUGMSG(D_EXTRA, "incoming packet more than 16 segments; dropping. (splitflag=%d)\n",
 281                                        soft->split_flag);
 282                                 lp->rfc1201.aborted_seq = soft->sequence;
 283                                 lp->stats.rx_errors++;
 284                                 lp->stats.rx_length_errors++;
 285                                 return;
 286                         }
 287                         in->skb = skb = alloc_skb(508 * in->numpackets + ARC_HDR_SIZE,
 288                                                   GFP_ATOMIC);
 289                         if (skb == NULL) {
 290                                 BUGMSG(D_NORMAL, "(split) memory squeeze, dropping packet.\n");
 291                                 lp->rfc1201.aborted_seq = soft->sequence;
 292                                 lp->stats.rx_dropped++;
 293                                 return;
 294                         }
 295                         skb->dev = dev;
 296                         pkt = (struct archdr *) skb->data;
 297                         soft = &pkt->soft.rfc1201;
 298
 299                         memcpy(pkt, pkthdr, ARC_HDR_SIZE + RFC1201_HDR_SIZE);
 300                         skb_put(skb, ARC_HDR_SIZE + RFC1201_HDR_SIZE);
 301
 302                         soft->split_flag = 0;   /* end result won't be split */
 303                 } else {        /* not first packet */
 304                         int packetnum = ((unsigned) soft->split_flag >> 1) + 1;
 305
 306                         /*
 307                          * if we're not assembling, there's no point trying to
 308                          * continue.
 309                          */
 310                         if (!in->skb) {
 311                                 if (lp->rfc1201.aborted_seq != soft->sequence) {
 312                                         BUGMSG(D_EXTRA, "can't continue split without starting "
 313                                                "first! (splitflag=%d, seq=%d, aborted=%d)\n",
 314                                         soft->split_flag, soft->sequence,
 315                                                lp->rfc1201.aborted_seq);
 316                                         lp->stats.rx_errors++;
 317                                         lp->stats.rx_missed_errors++;
 318                                 }
 319                                 return;
 320                         }
 321                         in->lastpacket++;
 322                         if (packetnum != in->lastpacket) {      /* not the right flag! */
 323                                 /* harmless duplicate? ignore. */
 324                                 if (packetnum <= in->lastpacket - 1) {
 325                                         BUGMSG(D_EXTRA, "duplicate splitpacket ignored! (splitflag=%d)\n",
 326                                                soft->split_flag);
 327                                         lp->stats.rx_errors++;
 328                                         lp->stats.rx_frame_errors++;
 329                                         return;
 330                                 }
 331                                 /* "bad" duplicate, kill reassembly */
 332                                 BUGMSG(D_EXTRA, "out-of-order splitpacket, reassembly "
 333                                        "(seq=%d) aborted (splitflag=%d, seq=%d)\n",
 334                                        in->sequence, soft->split_flag, soft->sequence);
 335                                 lp->rfc1201.aborted_seq = soft->sequence;
 336                                 dev_kfree_skb_irq(in->skb);
 337                                 in->skb = NULL;
 338                                 lp->stats.rx_errors++;
 339                                 lp->stats.rx_missed_errors++;
 340                                 in->lastpacket = in->numpackets = 0;
 341                                 return;
 342                         }
 343                         pkt = (struct archdr *) in->skb->data;
 344                         soft = &pkt->soft.rfc1201;
 345                 }
 346
 347                 skb = in->skb;
 348
 349                 lp->hw.copy_from_card(dev, bufnum, ofs + RFC1201_HDR_SIZE,
 350                                       skb->data + skb->len,
 351                                       length - RFC1201_HDR_SIZE);
 352                 skb_put(skb, length - RFC1201_HDR_SIZE);
 353
 354                 /* are we done? */
 355                 if (in->lastpacket == in->numpackets) {
 356                         in->skb = NULL;
 357                         in->lastpacket = in->numpackets = 0;
 358
 359             BUGMSG(D_SKB_SIZE, "skb: received %d bytes from %02X (unsplit)\n",
 360                 skb->len, pkt->hard.source);
 361             BUGMSG(D_SKB_SIZE, "skb: received %d bytes from %02X (split)\n",
 362                 skb->len, pkt->hard.source);
 363                         BUGLVL(D_SKB) arcnet_dump_skb(dev, skb, "rx");
 364
 365                         skb->protocol = type_trans(skb, dev);
 366                         netif_rx(skb);
 367                         dev->last_rx = jiffies;
 368                 }
 369         }
 370 }
 371
 372
 373 /* Create the ARCnet hard/soft headers for RFC1201. */
 374 static int build_header(struct sk_buff *skb, struct net_device *dev,
 375                         unsigned short type, uint8_t daddr)
 376 {
 377         struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
 378         int hdr_size = ARC_HDR_SIZE + RFC1201_HDR_SIZE;
 379         struct archdr *pkt = (struct archdr *) skb_push(skb, hdr_size);
 380         struct arc_rfc1201 *soft = &pkt->soft.rfc1201;
 381
 382         /* set the protocol ID according to RFC1201 */
 383         switch (type) {
 384         case ETH_P_IP:
 385                 soft->proto = ARC_P_IP;
 386                 break;
 387         case ETH_P_IPV6:
 388                 soft->proto = ARC_P_IPV6;
 389                 break;
 390         case ETH_P_ARP:
 391                 soft->proto = ARC_P_ARP;
 392                 break;
 393         case ETH_P_RARP:
 394                 soft->proto = ARC_P_RARP;
 395                 break;
 396         case ETH_P_IPX:
 397         case ETH_P_802_3:
 398         case ETH_P_802_2:
 399                 soft->proto = ARC_P_IPX;
 400                 break;
 401         case ETH_P_ATALK:
 402                 soft->proto = ARC_P_ATALK;
 403                 break;
 404         default:
 405                 BUGMSG(D_NORMAL, "RFC1201: I don't understand protocol %d (%Xh)\n",
 406                        type, type);
 407                 lp->stats.tx_errors++;
 408                 lp->stats.tx_aborted_errors++;
 409                 return 0;
 410         }
 411
 412         /*
 413          * Set the source hardware address.
 414          *
 415          * This is pretty pointless for most purposes, but it can help in
 416          * debugging.  ARCnet does not allow us to change the source address in
 417          * the actual packet sent)
 418          */
 419         pkt->hard.source = *dev->dev_addr;
 420
 421         soft->sequence = htons(lp->rfc1201.sequence++);
 422         soft->split_flag = 0;   /* split packets are done elsewhere */
 423
 424         /* see linux/net/ethernet/eth.c to see where I got the following */
 425
 426         if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
 427                 /*
 428                  * FIXME: fill in the last byte of the dest ipaddr here to better
 429                  * comply with RFC1051 in "noarp" mode.  For now, always broadcasting
 430                  * will probably at least get packets sent out :)
 431                  */
 432                 pkt->hard.dest = 0;
 433                 return hdr_size;
 434         }
 435         /* otherwise, drop in the dest address */
 436         pkt->hard.dest = daddr;
 437         return hdr_size;
 438 }
 439
 440
 441 static void load_pkt(struct net_device *dev, struct arc_hardware *hard,
 442                      struct arc_rfc1201 *soft, int softlen, int bufnum)
 443 {
 444         struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
 445         int ofs;
 446
 447         /* assume length <= XMTU: someone should have handled that by now. */
 448
 449         if (softlen > MinTU) {
 450                 hard->offset[0] = 0;
 451                 hard->offset[1] = ofs = 512 - softlen;
 452         } else if (softlen > MTU) {     /* exception packet - add an extra header */
 453                 struct arc_rfc1201 excsoft;
 454
 455                 excsoft.proto = soft->proto;
 456                 excsoft.split_flag = 0xff;
 457                 excsoft.sequence = 0xffff;
 458
 459                 hard->offset[0] = 0;
 460                 ofs = 512 - softlen;
 461                 hard->offset[1] = ofs - RFC1201_HDR_SIZE;
 462                 lp->hw.copy_to_card(dev, bufnum, ofs - RFC1201_HDR_SIZE,
 463                                     &excsoft, RFC1201_HDR_SIZE);
 464         } else
 465                 hard->offset[0] = ofs = 256 - softlen;
 466
 467         lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE);
 468         lp->hw.copy_to_card(dev, bufnum, ofs, soft, softlen);
 469
 470         lp->lastload_dest = hard->dest;
 471 }
 472
 473
 474 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
 475                       int bufnum)
 476 {
 477         struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
 478         const int maxsegsize = XMTU - RFC1201_HDR_SIZE;
 479         struct Outgoing *out;
 480
 481
 482         BUGMSG(D_DURING, "prepare_tx: txbufs=%d/%d/%d\n",
 483                lp->next_tx, lp->cur_tx, bufnum);
 484
 485         length -= ARC_HDR_SIZE; /* hard header is not included in packet length */
 486         pkt->soft.rfc1201.split_flag = 0;
 487
 488         /* need to do a split packet? */
 489         if (length > XMTU) {
 490                 out = &lp->outgoing;
 491
 492                 out->length = length - RFC1201_HDR_SIZE;
 493                 out->dataleft = lp->outgoing.length;
 494                 out->numsegs = (out->dataleft + maxsegsize - 1) / maxsegsize;
 495                 out->segnum = 0;
 496
 497                 BUGMSG(D_DURING, "rfc1201 prep_tx: ready for %d-segment split "
 498                        "(%d bytes, seq=%d)\n", out->numsegs, out->length,
 499                        pkt->soft.rfc1201.sequence);
 500
 501                 return 0;       /* not done */
 502         }
 503         /* just load the packet into the buffers and send it off */
 504         load_pkt(dev, &pkt->hard, &pkt->soft.rfc1201, length, bufnum);
 505
 506         return 1;               /* done */
 507 }
 508
 509
 510 static int continue_tx(struct net_device *dev, int bufnum)
 511 {
 512         struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
 513         struct Outgoing *out = &lp->outgoing;
 514         struct arc_hardware *hard = &out->pkt->hard;
 515         struct arc_rfc1201 *soft = &out->pkt->soft.rfc1201, *newsoft;
 516         int maxsegsize = XMTU - RFC1201_HDR_SIZE;
 517         int seglen;
 518
 519         BUGMSG(D_DURING,
 520           "rfc1201 continue_tx: loading segment %d(+1) of %d (seq=%d)\n",
 521                out->segnum, out->numsegs, soft->sequence);
 522
 523         /* the "new" soft header comes right before the data chunk */
 524         newsoft = (struct arc_rfc1201 *)
 525             (out->pkt->soft.raw + out->length - out->dataleft);
 526
 527         if (!out->segnum)       /* first packet; newsoft == soft */
 528                 newsoft->split_flag = ((out->numsegs - 2) << 1) | 1;
 529         else {
 530                 newsoft->split_flag = out->segnum << 1;
 531                 newsoft->proto = soft->proto;
 532                 newsoft->sequence = soft->sequence;
 533         }
 534
 535         seglen = maxsegsize;
 536         if (seglen > out->dataleft)
 537                 seglen = out->dataleft;
 538         out->dataleft -= seglen;
 539
 540         load_pkt(dev, hard, newsoft, seglen + RFC1201_HDR_SIZE, bufnum);
 541
 542         out->segnum++;
 543         if (out->segnum >= out->numsegs)
 544                 return 1;
 545         else
 546                 return 0;
 547 }