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/gfp.h>
  27 #include <linux/module.h>
  28 #include <linux/init.h>
  29 #include <linux/if_arp.h>
  30 #include <linux/netdevice.h>
  31 #include <linux/skbuff.h>
  32 #include <linux/arcdevice.h>
  33
  34 MODULE_LICENSE("GPL");
  35 #define VERSION "arcnet: RFC1201 \"standard\" (`a') encapsulation support loaded.\n"
  36
  37 static __be16 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 static struct ArcProto rfc1201_proto =
  47 {
  48         .suffix         = 'a',
  49         .mtu            = 1500, /* could be more, but some receivers can't handle it... */
  50         .is_ip          = 1,    /* This is for sending IP and ARP packages */
  51         .rx             = rx,
  52         .build_header   = build_header,
  53         .prepare_tx     = prepare_tx,
  54         .continue_tx    = continue_tx,
  55         .ack_tx         = NULL
  56 };
  57
  58 static int __init arcnet_rfc1201_init(void)
  59 {
  60         printk(VERSION);
  61
  62         arc_proto_map[ARC_P_IP]
  63             = arc_proto_map[ARC_P_IPV6]
  64             = arc_proto_map[ARC_P_ARP]
  65             = arc_proto_map[ARC_P_RARP]
  66             = arc_proto_map[ARC_P_IPX]
  67             = arc_proto_map[ARC_P_NOVELL_EC]
  68             = &rfc1201_proto;
  69
  70         /* if someone else already owns the broadcast, we won't take it */
  71         if (arc_bcast_proto == arc_proto_default)
  72                 arc_bcast_proto = &rfc1201_proto;
  73
  74         return 0;
  75 }
  76
  77 static void __exit arcnet_rfc1201_exit(void)
  78 {
  79         arcnet_unregister_proto(&rfc1201_proto);
  80 }
  81
  82 module_init(arcnet_rfc1201_init);
  83 module_exit(arcnet_rfc1201_exit);
  84
  85 /*
  86  * Determine a packet's protocol ID.
  87  *
  88  * With ARCnet we have to convert everything to Ethernet-style stuff.
  89  */
  90 static __be16 type_trans(struct sk_buff *skb, struct net_device *dev)
  91 {
  92         struct archdr *pkt = (struct archdr *)skb->data;
  93         struct arc_rfc1201 *soft = &pkt->soft.rfc1201;
  94         int hdr_size = ARC_HDR_SIZE + RFC1201_HDR_SIZE;
  95
  96         /* Pull off the arcnet header. */
  97         skb_reset_mac_header(skb);
  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                 dev->stats.rx_errors++;
 123                 dev->stats.rx_crc_errors++;
 124                 return 0;
 125         }
 126
 127         return htons(ETH_P_IP);
 128 }
 129
 130 /* packet receiver */
 131 static void rx(struct net_device *dev, int bufnum,
 132                struct archdr *pkthdr, int length)
 133 {
 134         struct arcnet_local *lp = netdev_priv(dev);
 135         struct sk_buff *skb;
 136         struct archdr *pkt = pkthdr;
 137         struct arc_rfc1201 *soft = &pkthdr->soft.rfc1201;
 138         int saddr = pkt->hard.source, ofs;
 139         struct Incoming *in = &lp->rfc1201.incoming[saddr];
 140
 141         BUGMSG(D_DURING, "it's an RFC1201 packet (length=%d)\n", length);
 142
 143         if (length >= MinTU)
 144                 ofs = 512 - length;
 145         else
 146                 ofs = 256 - length;
 147
 148         if (soft->split_flag == 0xFF) {         /* Exception Packet */
 149                 if (length >= 4 + RFC1201_HDR_SIZE)
 150                         BUGMSG(D_DURING, "compensating for exception packet\n");
 151                 else {
 152                         BUGMSG(D_EXTRA, "short RFC1201 exception packet from %02Xh",
 153                                saddr);
 154                         return;
 155                 }
 156
 157                 /* skip over 4-byte junkola */
 158                 length -= 4;
 159                 ofs += 4;
 160                 lp->hw.copy_from_card(dev, bufnum, 512 - length,
 161                                       soft, sizeof(pkt->soft));
 162         }
 163         if (!soft->split_flag) {        /* not split */
 164                 BUGMSG(D_RX, "incoming is not split (splitflag=%d)\n",
 165                        soft->split_flag);
 166
 167                 if (in->skb) {  /* already assembling one! */
 168                         BUGMSG(D_EXTRA, "aborting assembly (seq=%d) for unsplit packet (splitflag=%d, seq=%d)\n",
 169                                in->sequence, soft->split_flag, soft->sequence);
 170                         lp->rfc1201.aborted_seq = soft->sequence;
 171                         dev_kfree_skb_irq(in->skb);
 172                         dev->stats.rx_errors++;
 173                         dev->stats.rx_missed_errors++;
 174                         in->skb = NULL;
 175                 }
 176                 in->sequence = soft->sequence;
 177
 178                 skb = alloc_skb(length + ARC_HDR_SIZE, GFP_ATOMIC);
 179                 if (skb == NULL) {
 180                         BUGMSG(D_NORMAL, "Memory squeeze, dropping packet.\n");
 181                         dev->stats.rx_dropped++;
 182                         return;
 183                 }
 184                 skb_put(skb, length + ARC_HDR_SIZE);
 185                 skb->dev = dev;
 186
 187                 pkt = (struct archdr *)skb->data;
 188                 soft = &pkt->soft.rfc1201;
 189
 190                 /* up to sizeof(pkt->soft) has already been copied from the card */
 191                 memcpy(pkt, pkthdr, sizeof(struct archdr));
 192                 if (length > sizeof(pkt->soft))
 193                         lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft),
 194                                        pkt->soft.raw + sizeof(pkt->soft),
 195                                               length - sizeof(pkt->soft));
 196
 197                 /*
 198                  * ARP packets have problems when sent from some DOS systems: the
 199                  * source address is always 0!  So we take the hardware source addr
 200                  * (which is impossible to fumble) and insert it ourselves.
 201                  */
 202                 if (soft->proto == ARC_P_ARP) {
 203                         struct arphdr *arp = (struct arphdr *)soft->payload;
 204
 205                         /* make sure addresses are the right length */
 206                         if (arp->ar_hln == 1 && arp->ar_pln == 4) {
 207                                 uint8_t *cptr = (uint8_t *)arp + sizeof(struct arphdr);
 208
 209                                 if (!*cptr) {   /* is saddr = 00? */
 210                                         BUGMSG(D_EXTRA,
 211                                                "ARP source address was 00h, set to %02Xh.\n",
 212                                                saddr);
 213                                         dev->stats.rx_crc_errors++;
 214                                         *cptr = saddr;
 215                                 } else {
 216                                         BUGMSG(D_DURING, "ARP source address (%Xh) is fine.\n",
 217                                                *cptr);
 218                                 }
 219                         } else {
 220                                 BUGMSG(D_NORMAL, "funny-shaped ARP packet. (%Xh, %Xh)\n",
 221                                        arp->ar_hln, arp->ar_pln);
 222                                 dev->stats.rx_errors++;
 223                                 dev->stats.rx_crc_errors++;
 224                         }
 225                 }
 226                 BUGLVL(D_SKB) arcnet_dump_skb(dev, skb, "rx");
 227
 228                 skb->protocol = type_trans(skb, dev);
 229                 netif_rx(skb);
 230         } else {                /* split packet */
 231                 /*
 232                  * NOTE: MSDOS ARP packet correction should only need to apply to
 233                  * unsplit packets, since ARP packets are so short.
 234                  *
 235                  * My interpretation of the RFC1201 document is that if a packet is
 236                  * received out of order, the entire assembly process should be
 237                  * aborted.
 238                  *
 239                  * The RFC also mentions "it is possible for successfully received
 240                  * packets to be retransmitted." As of 0.40 all previously received
 241                  * packets are allowed, not just the most recent one.
 242                  *
 243                  * We allow multiple assembly processes, one for each ARCnet card
 244                  * possible on the network.  Seems rather like a waste of memory,
 245                  * but there's no other way to be reliable.
 246                  */
 247
 248                 BUGMSG(D_RX, "packet is split (splitflag=%d, seq=%d)\n",
 249                        soft->split_flag, in->sequence);
 250
 251                 if (in->skb && in->sequence != soft->sequence) {
 252                         BUGMSG(D_EXTRA, "wrong seq number (saddr=%d, expected=%d, seq=%d, splitflag=%d)\n",
 253                                saddr, in->sequence, soft->sequence,
 254                                soft->split_flag);
 255                         dev_kfree_skb_irq(in->skb);
 256                         in->skb = NULL;
 257                         dev->stats.rx_errors++;
 258                         dev->stats.rx_missed_errors++;
 259                         in->lastpacket = in->numpackets = 0;
 260                 }
 261                 if (soft->split_flag & 1) {     /* first packet in split */
 262                         BUGMSG(D_RX, "brand new splitpacket (splitflag=%d)\n",
 263                                soft->split_flag);
 264                         if (in->skb) {  /* already assembling one! */
 265                                 BUGMSG(D_EXTRA, "aborting previous (seq=%d) assembly "
 266                                        "(splitflag=%d, seq=%d)\n",
 267                                        in->sequence, soft->split_flag,
 268                                        soft->sequence);
 269                                 dev->stats.rx_errors++;
 270                                 dev->stats.rx_missed_errors++;
 271                                 dev_kfree_skb_irq(in->skb);
 272                         }
 273                         in->sequence = soft->sequence;
 274                         in->numpackets = ((unsigned)soft->split_flag >> 1) + 2;
 275                         in->lastpacket = 1;
 276
 277                         if (in->numpackets > 16) {
 278                                 BUGMSG(D_EXTRA, "incoming packet more than 16 segments; dropping. (splitflag=%d)\n",
 279                                        soft->split_flag);
 280                                 lp->rfc1201.aborted_seq = soft->sequence;
 281                                 dev->stats.rx_errors++;
 282                                 dev->stats.rx_length_errors++;
 283                                 return;
 284                         }
 285                         in->skb = skb = alloc_skb(508 * in->numpackets + ARC_HDR_SIZE,
 286                                                   GFP_ATOMIC);
 287                         if (skb == NULL) {
 288                                 BUGMSG(D_NORMAL, "(split) memory squeeze, dropping packet.\n");
 289                                 lp->rfc1201.aborted_seq = soft->sequence;
 290                                 dev->stats.rx_dropped++;
 291                                 return;
 292                         }
 293                         skb->dev = dev;
 294                         pkt = (struct archdr *)skb->data;
 295                         soft = &pkt->soft.rfc1201;
 296
 297                         memcpy(pkt, pkthdr, ARC_HDR_SIZE + RFC1201_HDR_SIZE);
 298                         skb_put(skb, ARC_HDR_SIZE + RFC1201_HDR_SIZE);
 299
 300                         soft->split_flag = 0;   /* end result won't be split */
 301                 } else {        /* not first packet */
 302                         int packetnum = ((unsigned)soft->split_flag >> 1) + 1;
 303
 304                         /*
 305                          * if we're not assembling, there's no point trying to
 306                          * continue.
 307                          */
 308                         if (!in->skb) {
 309                                 if (lp->rfc1201.aborted_seq != soft->sequence) {
 310                                         BUGMSG(D_EXTRA, "can't continue split without starting "
 311                                                "first! (splitflag=%d, seq=%d, aborted=%d)\n",
 312                                         soft->split_flag, soft->sequence,
 313                                                lp->rfc1201.aborted_seq);
 314                                         dev->stats.rx_errors++;
 315                                         dev->stats.rx_missed_errors++;
 316                                 }
 317                                 return;
 318                         }
 319                         in->lastpacket++;
 320                         if (packetnum != in->lastpacket) {      /* not the right flag! */
 321                                 /* harmless duplicate? ignore. */
 322                                 if (packetnum <= in->lastpacket - 1) {
 323                                         BUGMSG(D_EXTRA, "duplicate splitpacket ignored! (splitflag=%d)\n",
 324                                                soft->split_flag);
 325                                         dev->stats.rx_errors++;
 326                                         dev->stats.rx_frame_errors++;
 327                                         return;
 328                                 }
 329                                 /* "bad" duplicate, kill reassembly */
 330                                 BUGMSG(D_EXTRA, "out-of-order splitpacket, reassembly "
 331                                        "(seq=%d) aborted (splitflag=%d, seq=%d)\n",
 332                                        in->sequence, soft->split_flag, soft->sequence);
 333                                 lp->rfc1201.aborted_seq = soft->sequence;
 334                                 dev_kfree_skb_irq(in->skb);
 335                                 in->skb = NULL;
 336                                 dev->stats.rx_errors++;
 337                                 dev->stats.rx_missed_errors++;
 338                                 in->lastpacket = in->numpackets = 0;
 339                                 return;
 340                         }
 341                         pkt = (struct archdr *)in->skb->data;
 342                         soft = &pkt->soft.rfc1201;
 343                 }
 344
 345                 skb = in->skb;
 346
 347                 lp->hw.copy_from_card(dev, bufnum, ofs + RFC1201_HDR_SIZE,
 348                                       skb->data + skb->len,
 349                                       length - RFC1201_HDR_SIZE);
 350                 skb_put(skb, length - RFC1201_HDR_SIZE);
 351
 352                 /* are we done? */
 353                 if (in->lastpacket == in->numpackets) {
 354                         in->skb = NULL;
 355                         in->lastpacket = in->numpackets = 0;
 356
 357                         BUGMSG(D_SKB_SIZE, "skb: received %d bytes from %02X (unsplit)\n",
 358                                skb->len, pkt->hard.source);
 359                         BUGMSG(D_SKB_SIZE, "skb: received %d bytes from %02X (split)\n",
 360                                skb->len, pkt->hard.source);
 361                         BUGLVL(D_SKB) arcnet_dump_skb(dev, skb, "rx");
 362
 363                         skb->protocol = type_trans(skb, dev);
 364                         netif_rx(skb);
 365                 }
 366         }
 367 }
 368
 369 /* Create the ARCnet hard/soft headers for RFC1201. */
 370 static int build_header(struct sk_buff *skb, struct net_device *dev,
 371                         unsigned short type, uint8_t daddr)
 372 {
 373         struct arcnet_local *lp = netdev_priv(dev);
 374         int hdr_size = ARC_HDR_SIZE + RFC1201_HDR_SIZE;
 375         struct archdr *pkt = (struct archdr *)skb_push(skb, hdr_size);
 376         struct arc_rfc1201 *soft = &pkt->soft.rfc1201;
 377
 378         /* set the protocol ID according to RFC1201 */
 379         switch (type) {
 380         case ETH_P_IP:
 381                 soft->proto = ARC_P_IP;
 382                 break;
 383         case ETH_P_IPV6:
 384                 soft->proto = ARC_P_IPV6;
 385                 break;
 386         case ETH_P_ARP:
 387                 soft->proto = ARC_P_ARP;
 388                 break;
 389         case ETH_P_RARP:
 390                 soft->proto = ARC_P_RARP;
 391                 break;
 392         case ETH_P_IPX:
 393         case ETH_P_802_3:
 394         case ETH_P_802_2:
 395                 soft->proto = ARC_P_IPX;
 396                 break;
 397         case ETH_P_ATALK:
 398                 soft->proto = ARC_P_ATALK;
 399                 break;
 400         default:
 401                 BUGMSG(D_NORMAL, "RFC1201: I don't understand protocol %d (%Xh)\n",
 402                        type, type);
 403                 dev->stats.tx_errors++;
 404                 dev->stats.tx_aborted_errors++;
 405                 return 0;
 406         }
 407
 408         /*
 409          * Set the source hardware address.
 410          *
 411          * This is pretty pointless for most purposes, but it can help in
 412          * debugging.  ARCnet does not allow us to change the source address in
 413          * the actual packet sent)
 414          */
 415         pkt->hard.source = *dev->dev_addr;
 416
 417         soft->sequence = htons(lp->rfc1201.sequence++);
 418         soft->split_flag = 0;   /* split packets are done elsewhere */
 419
 420         /* see linux/net/ethernet/eth.c to see where I got the following */
 421
 422         if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
 423                 /*
 424                  * FIXME: fill in the last byte of the dest ipaddr here to better
 425                  * comply with RFC1051 in "noarp" mode.  For now, always broadcasting
 426                  * will probably at least get packets sent out :)
 427                  */
 428                 pkt->hard.dest = 0;
 429                 return hdr_size;
 430         }
 431         /* otherwise, drop in the dest address */
 432         pkt->hard.dest = daddr;
 433         return hdr_size;
 434 }
 435
 436 static void load_pkt(struct net_device *dev, struct arc_hardware *hard,
 437                      struct arc_rfc1201 *soft, int softlen, int bufnum)
 438 {
 439         struct arcnet_local *lp = netdev_priv(dev);
 440         int ofs;
 441
 442         /* assume length <= XMTU: someone should have handled that by now. */
 443
 444         if (softlen > MinTU) {
 445                 hard->offset[0] = 0;
 446                 hard->offset[1] = ofs = 512 - softlen;
 447         } else if (softlen > MTU) {     /* exception packet - add an extra header */
 448                 struct arc_rfc1201 excsoft;
 449
 450                 excsoft.proto = soft->proto;
 451                 excsoft.split_flag = 0xff;
 452                 excsoft.sequence = htons(0xffff);
 453
 454                 hard->offset[0] = 0;
 455                 ofs = 512 - softlen;
 456                 hard->offset[1] = ofs - RFC1201_HDR_SIZE;
 457                 lp->hw.copy_to_card(dev, bufnum, ofs - RFC1201_HDR_SIZE,
 458                                     &excsoft, RFC1201_HDR_SIZE);
 459         } else
 460                 hard->offset[0] = ofs = 256 - softlen;
 461
 462         lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE);
 463         lp->hw.copy_to_card(dev, bufnum, ofs, soft, softlen);
 464
 465         lp->lastload_dest = hard->dest;
 466 }
 467
 468 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
 469                       int bufnum)
 470 {
 471         struct arcnet_local *lp = netdev_priv(dev);
 472         const int maxsegsize = XMTU - RFC1201_HDR_SIZE;
 473         struct Outgoing *out;
 474
 475         BUGMSG(D_DURING, "prepare_tx: txbufs=%d/%d/%d\n",
 476                lp->next_tx, lp->cur_tx, bufnum);
 477
 478         length -= ARC_HDR_SIZE; /* hard header is not included in packet length */
 479         pkt->soft.rfc1201.split_flag = 0;
 480
 481         /* need to do a split packet? */
 482         if (length > XMTU) {
 483                 out = &lp->outgoing;
 484
 485                 out->length = length - RFC1201_HDR_SIZE;
 486                 out->dataleft = lp->outgoing.length;
 487                 out->numsegs = (out->dataleft + maxsegsize - 1) / maxsegsize;
 488                 out->segnum = 0;
 489
 490                 BUGMSG(D_DURING, "rfc1201 prep_tx: ready for %d-segment split "
 491                        "(%d bytes, seq=%d)\n", out->numsegs, out->length,
 492                        pkt->soft.rfc1201.sequence);
 493
 494                 return 0;       /* not done */
 495         }
 496         /* just load the packet into the buffers and send it off */
 497         load_pkt(dev, &pkt->hard, &pkt->soft.rfc1201, length, bufnum);
 498
 499         return 1;               /* done */
 500 }
 501
 502 static int continue_tx(struct net_device *dev, int bufnum)
 503 {
 504         struct arcnet_local *lp = netdev_priv(dev);
 505         struct Outgoing *out = &lp->outgoing;
 506         struct arc_hardware *hard = &out->pkt->hard;
 507         struct arc_rfc1201 *soft = &out->pkt->soft.rfc1201, *newsoft;
 508         int maxsegsize = XMTU - RFC1201_HDR_SIZE;
 509         int seglen;
 510
 511         BUGMSG(D_DURING,
 512                "rfc1201 continue_tx: loading segment %d(+1) of %d (seq=%d)\n",
 513                out->segnum, out->numsegs, soft->sequence);
 514
 515         /* the "new" soft header comes right before the data chunk */
 516         newsoft = (struct arc_rfc1201 *)
 517             (out->pkt->soft.raw + out->length - out->dataleft);
 518
 519         if (!out->segnum)       /* first packet; newsoft == soft */
 520                 newsoft->split_flag = ((out->numsegs - 2) << 1) | 1;
 521         else {
 522                 newsoft->split_flag = out->segnum << 1;
 523                 newsoft->proto = soft->proto;
 524                 newsoft->sequence = soft->sequence;
 525         }
 526
 527         seglen = maxsegsize;
 528         if (seglen > out->dataleft)
 529                 seglen = out->dataleft;
 530         out->dataleft -= seglen;
 531
 532         load_pkt(dev, hard, newsoft, seglen + RFC1201_HDR_SIZE, bufnum);
 533
 534         out->segnum++;
 535         if (out->segnum >= out->numsegs)
 536                 return 1;
 537         else
 538                 return 0;
 539 }