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 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
  59 static int __init arcnet_rfc1201_init(void)
  60 {
  61         printk(VERSION);
  62
  63         arc_proto_map[ARC_P_IP]
  64             = arc_proto_map[ARC_P_IPV6]
  65             = arc_proto_map[ARC_P_ARP]
  66             = arc_proto_map[ARC_P_RARP]
  67             = arc_proto_map[ARC_P_IPX]
  68             = arc_proto_map[ARC_P_NOVELL_EC]
  69             = &rfc1201_proto;
  70
  71         /* if someone else already owns the broadcast, we won't take it */
  72         if (arc_bcast_proto == arc_proto_default)
  73                 arc_bcast_proto = &rfc1201_proto;
  74
  75         return 0;
  76 }
  77
  78 static void __exit arcnet_rfc1201_exit(void)
  79 {
  80         arcnet_unregister_proto(&rfc1201_proto);
  81 }
  82
  83 module_init(arcnet_rfc1201_init);
  84 module_exit(arcnet_rfc1201_exit);
  85
  86 /*
  87  * Determine a packet's protocol ID.
  88  *
  89  * With ARCnet we have to convert everything to Ethernet-style stuff.
  90  */
  91 static unsigned short type_trans(struct sk_buff *skb, struct net_device *dev)
  92 {
  93         struct archdr *pkt = (struct archdr *) skb->data;
  94         struct arc_rfc1201 *soft = &pkt->soft.rfc1201;
  95         struct arcnet_local *lp = dev->priv;
  96         int hdr_size = ARC_HDR_SIZE + RFC1201_HDR_SIZE;
  97
  98         /* Pull off the arcnet header. */
  99         skb_reset_mac_header(skb);
 100         skb_pull(skb, hdr_size);
 101
 102         if (pkt->hard.dest == 0)
 103                 skb->pkt_type = PACKET_BROADCAST;
 104         else if (dev->flags & IFF_PROMISC) {
 105                 /* if we're not sending to ourselves :) */
 106                 if (pkt->hard.dest != dev->dev_addr[0])
 107                         skb->pkt_type = PACKET_OTHERHOST;
 108         }
 109         /* now return the protocol number */
 110         switch (soft->proto) {
 111         case ARC_P_IP:
 112                 return htons(ETH_P_IP);
 113         case ARC_P_IPV6:
 114                 return htons(ETH_P_IPV6);
 115         case ARC_P_ARP:
 116                 return htons(ETH_P_ARP);
 117         case ARC_P_RARP:
 118                 return htons(ETH_P_RARP);
 119
 120         case ARC_P_IPX:
 121         case ARC_P_NOVELL_EC:
 122                 return htons(ETH_P_802_3);
 123         default:
 124                 lp->stats.rx_errors++;
 125                 lp->stats.rx_crc_errors++;
 126                 return 0;
 127         }
 128
 129         return htons(ETH_P_IP);
 130 }
 131
 132
 133 /* packet receiver */
 134 static void rx(struct net_device *dev, int bufnum,
 135                struct archdr *pkthdr, int length)
 136 {
 137         struct arcnet_local *lp = dev->priv;
 138         struct sk_buff *skb;
 139         struct archdr *pkt = pkthdr;
 140         struct arc_rfc1201 *soft = &pkthdr->soft.rfc1201;
 141         int saddr = pkt->hard.source, ofs;
 142         struct Incoming *in = &lp->rfc1201.incoming[saddr];
 143
 144         BUGMSG(D_DURING, "it's an RFC1201 packet (length=%d)\n", length);
 145
 146         if (length >= MinTU)
 147                 ofs = 512 - length;
 148         else
 149                 ofs = 256 - length;
 150
 151         if (soft->split_flag == 0xFF) {         /* Exception Packet */
 152                 if (length >= 4 + RFC1201_HDR_SIZE)
 153                         BUGMSG(D_DURING, "compensating for exception packet\n");
 154                 else {
 155                         BUGMSG(D_EXTRA, "short RFC1201 exception packet from %02Xh",
 156                                saddr);
 157                         return;
 158                 }
 159
 160                 /* skip over 4-byte junkola */
 161                 length -= 4;
 162                 ofs += 4;
 163                 lp->hw.copy_from_card(dev, bufnum, 512 - length,
 164                                       soft, sizeof(pkt->soft));
 165         }
 166         if (!soft->split_flag) {        /* not split */
 167                 BUGMSG(D_RX, "incoming is not split (splitflag=%d)\n",
 168                        soft->split_flag);
 169
 170                 if (in->skb) {  /* already assembling one! */
 171                         BUGMSG(D_EXTRA, "aborting assembly (seq=%d) for unsplit packet (splitflag=%d, seq=%d)\n",
 172                          in->sequence, soft->split_flag, soft->sequence);
 173                         lp->rfc1201.aborted_seq = soft->sequence;
 174                         dev_kfree_skb_irq(in->skb);
 175                         lp->stats.rx_errors++;
 176                         lp->stats.rx_missed_errors++;
 177                         in->skb = NULL;
 178                 }
 179                 in->sequence = soft->sequence;
 180
 181                 skb = alloc_skb(length + ARC_HDR_SIZE, GFP_ATOMIC);
 182                 if (skb == NULL) {
 183                         BUGMSG(D_NORMAL, "Memory squeeze, dropping packet.\n");
 184                         lp->stats.rx_dropped++;
 185                         return;
 186                 }
 187                 skb_put(skb, length + ARC_HDR_SIZE);
 188                 skb->dev = dev;
 189
 190                 pkt = (struct archdr *) skb->data;
 191                 soft = &pkt->soft.rfc1201;
 192
 193                 /* up to sizeof(pkt->soft) has already been copied from the card */
 194                 memcpy(pkt, pkthdr, sizeof(struct archdr));
 195                 if (length > sizeof(pkt->soft))
 196                         lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft),
 197                                        pkt->soft.raw + sizeof(pkt->soft),
 198                                               length - sizeof(pkt->soft));
 199
 200                 /*
 201                  * ARP packets have problems when sent from some DOS systems: the
 202                  * source address is always 0!  So we take the hardware source addr
 203                  * (which is impossible to fumble) and insert it ourselves.
 204                  */
 205                 if (soft->proto == ARC_P_ARP) {
 206                         struct arphdr *arp = (struct arphdr *) soft->payload;
 207
 208                         /* make sure addresses are the right length */
 209                         if (arp->ar_hln == 1 && arp->ar_pln == 4) {
 210                                 uint8_t *cptr = (uint8_t *) arp + sizeof(struct arphdr);
 211
 212                                 if (!*cptr) {   /* is saddr = 00? */
 213                                         BUGMSG(D_EXTRA,
 214                                                "ARP source address was 00h, set to %02Xh.\n",
 215                                                saddr);
 216                                         lp->stats.rx_crc_errors++;
 217                                         *cptr = saddr;
 218                                 } else {
 219                                         BUGMSG(D_DURING, "ARP source address (%Xh) is fine.\n",
 220                                                *cptr);
 221                                 }
 222                         } else {
 223                                 BUGMSG(D_NORMAL, "funny-shaped ARP packet. (%Xh, %Xh)\n",
 224                                        arp->ar_hln, arp->ar_pln);
 225                                 lp->stats.rx_errors++;
 226                                 lp->stats.rx_crc_errors++;
 227                         }
 228                 }
 229                 BUGLVL(D_SKB) arcnet_dump_skb(dev, skb, "rx");
 230
 231                 skb->protocol = type_trans(skb, dev);
 232                 netif_rx(skb);
 233                 dev->last_rx = jiffies;
 234         } else {                /* split packet */
 235                 /*
 236                  * NOTE: MSDOS ARP packet correction should only need to apply to
 237                  * unsplit packets, since ARP packets are so short.
 238                  *
 239                  * My interpretation of the RFC1201 document is that if a packet is
 240                  * received out of order, the entire assembly process should be
 241                  * aborted.
 242                  *
 243                  * The RFC also mentions "it is possible for successfully received
 244                  * packets to be retransmitted." As of 0.40 all previously received
 245                  * packets are allowed, not just the most recent one.
 246                  *
 247                  * We allow multiple assembly processes, one for each ARCnet card
 248                  * possible on the network.  Seems rather like a waste of memory,
 249                  * but there's no other way to be reliable.
 250                  */
 251
 252                 BUGMSG(D_RX, "packet is split (splitflag=%d, seq=%d)\n",
 253                        soft->split_flag, in->sequence);
 254
 255                 if (in->skb && in->sequence != soft->sequence) {
 256                         BUGMSG(D_EXTRA, "wrong seq number (saddr=%d, expected=%d, seq=%d, splitflag=%d)\n",
 257                                saddr, in->sequence, soft->sequence,
 258                                soft->split_flag);
 259                         dev_kfree_skb_irq(in->skb);
 260                         in->skb = NULL;
 261                         lp->stats.rx_errors++;
 262                         lp->stats.rx_missed_errors++;
 263                         in->lastpacket = in->numpackets = 0;
 264                 }
 265                 if (soft->split_flag & 1) {     /* first packet in split */
 266                         BUGMSG(D_RX, "brand new splitpacket (splitflag=%d)\n",
 267                                soft->split_flag);
 268                         if (in->skb) {  /* already assembling one! */
 269                                 BUGMSG(D_EXTRA, "aborting previous (seq=%d) assembly "
 270                                        "(splitflag=%d, seq=%d)\n",
 271                                        in->sequence, soft->split_flag,
 272                                        soft->sequence);
 273                                 lp->stats.rx_errors++;
 274                                 lp->stats.rx_missed_errors++;
 275                                 dev_kfree_skb_irq(in->skb);
 276                         }
 277                         in->sequence = soft->sequence;
 278                         in->numpackets = ((unsigned) soft->split_flag >> 1) + 2;
 279                         in->lastpacket = 1;
 280
 281                         if (in->numpackets > 16) {
 282                                 BUGMSG(D_EXTRA, "incoming packet more than 16 segments; dropping. (splitflag=%d)\n",
 283                                        soft->split_flag);
 284                                 lp->rfc1201.aborted_seq = soft->sequence;
 285                                 lp->stats.rx_errors++;
 286                                 lp->stats.rx_length_errors++;
 287                                 return;
 288                         }
 289                         in->skb = skb = alloc_skb(508 * in->numpackets + ARC_HDR_SIZE,
 290                                                   GFP_ATOMIC);
 291                         if (skb == NULL) {
 292                                 BUGMSG(D_NORMAL, "(split) memory squeeze, dropping packet.\n");
 293                                 lp->rfc1201.aborted_seq = soft->sequence;
 294                                 lp->stats.rx_dropped++;
 295                                 return;
 296                         }
 297                         skb->dev = dev;
 298                         pkt = (struct archdr *) skb->data;
 299                         soft = &pkt->soft.rfc1201;
 300
 301                         memcpy(pkt, pkthdr, ARC_HDR_SIZE + RFC1201_HDR_SIZE);
 302                         skb_put(skb, ARC_HDR_SIZE + RFC1201_HDR_SIZE);
 303
 304                         soft->split_flag = 0;   /* end result won't be split */
 305                 } else {        /* not first packet */
 306                         int packetnum = ((unsigned) soft->split_flag >> 1) + 1;
 307
 308                         /*
 309                          * if we're not assembling, there's no point trying to
 310                          * continue.
 311                          */
 312                         if (!in->skb) {
 313                                 if (lp->rfc1201.aborted_seq != soft->sequence) {
 314                                         BUGMSG(D_EXTRA, "can't continue split without starting "
 315                                                "first! (splitflag=%d, seq=%d, aborted=%d)\n",
 316                                         soft->split_flag, soft->sequence,
 317                                                lp->rfc1201.aborted_seq);
 318                                         lp->stats.rx_errors++;
 319                                         lp->stats.rx_missed_errors++;
 320                                 }
 321                                 return;
 322                         }
 323                         in->lastpacket++;
 324                         if (packetnum != in->lastpacket) {      /* not the right flag! */
 325                                 /* harmless duplicate? ignore. */
 326                                 if (packetnum <= in->lastpacket - 1) {
 327                                         BUGMSG(D_EXTRA, "duplicate splitpacket ignored! (splitflag=%d)\n",
 328                                                soft->split_flag);
 329                                         lp->stats.rx_errors++;
 330                                         lp->stats.rx_frame_errors++;
 331                                         return;
 332                                 }
 333                                 /* "bad" duplicate, kill reassembly */
 334                                 BUGMSG(D_EXTRA, "out-of-order splitpacket, reassembly "
 335                                        "(seq=%d) aborted (splitflag=%d, seq=%d)\n",
 336                                        in->sequence, soft->split_flag, soft->sequence);
 337                                 lp->rfc1201.aborted_seq = soft->sequence;
 338                                 dev_kfree_skb_irq(in->skb);
 339                                 in->skb = NULL;
 340                                 lp->stats.rx_errors++;
 341                                 lp->stats.rx_missed_errors++;
 342                                 in->lastpacket = in->numpackets = 0;
 343                                 return;
 344                         }
 345                         pkt = (struct archdr *) in->skb->data;
 346                         soft = &pkt->soft.rfc1201;
 347                 }
 348
 349                 skb = in->skb;
 350
 351                 lp->hw.copy_from_card(dev, bufnum, ofs + RFC1201_HDR_SIZE,
 352                                       skb->data + skb->len,
 353                                       length - RFC1201_HDR_SIZE);
 354                 skb_put(skb, length - RFC1201_HDR_SIZE);
 355
 356                 /* are we done? */
 357                 if (in->lastpacket == in->numpackets) {
 358                         in->skb = NULL;
 359                         in->lastpacket = in->numpackets = 0;
 360
 361             BUGMSG(D_SKB_SIZE, "skb: received %d bytes from %02X (unsplit)\n",
 362                 skb->len, pkt->hard.source);
 363             BUGMSG(D_SKB_SIZE, "skb: received %d bytes from %02X (split)\n",
 364                 skb->len, pkt->hard.source);
 365                         BUGLVL(D_SKB) arcnet_dump_skb(dev, skb, "rx");
 366
 367                         skb->protocol = type_trans(skb, dev);
 368                         netif_rx(skb);
 369                         dev->last_rx = jiffies;
 370                 }
 371         }
 372 }
 373
 374
 375 /* Create the ARCnet hard/soft headers for RFC1201. */
 376 static int build_header(struct sk_buff *skb, struct net_device *dev,
 377                         unsigned short type, uint8_t daddr)
 378 {
 379         struct arcnet_local *lp = dev->priv;
 380         int hdr_size = ARC_HDR_SIZE + RFC1201_HDR_SIZE;
 381         struct archdr *pkt = (struct archdr *) skb_push(skb, hdr_size);
 382         struct arc_rfc1201 *soft = &pkt->soft.rfc1201;
 383
 384         /* set the protocol ID according to RFC1201 */
 385         switch (type) {
 386         case ETH_P_IP:
 387                 soft->proto = ARC_P_IP;
 388                 break;
 389         case ETH_P_IPV6:
 390                 soft->proto = ARC_P_IPV6;
 391                 break;
 392         case ETH_P_ARP:
 393                 soft->proto = ARC_P_ARP;
 394                 break;
 395         case ETH_P_RARP:
 396                 soft->proto = ARC_P_RARP;
 397                 break;
 398         case ETH_P_IPX:
 399         case ETH_P_802_3:
 400         case ETH_P_802_2:
 401                 soft->proto = ARC_P_IPX;
 402                 break;
 403         case ETH_P_ATALK:
 404                 soft->proto = ARC_P_ATALK;
 405                 break;
 406         default:
 407                 BUGMSG(D_NORMAL, "RFC1201: I don't understand protocol %d (%Xh)\n",
 408                        type, type);
 409                 lp->stats.tx_errors++;
 410                 lp->stats.tx_aborted_errors++;
 411                 return 0;
 412         }
 413
 414         /*
 415          * Set the source hardware address.
 416          *
 417          * This is pretty pointless for most purposes, but it can help in
 418          * debugging.  ARCnet does not allow us to change the source address in
 419          * the actual packet sent)
 420          */
 421         pkt->hard.source = *dev->dev_addr;
 422
 423         soft->sequence = htons(lp->rfc1201.sequence++);
 424         soft->split_flag = 0;   /* split packets are done elsewhere */
 425
 426         /* see linux/net/ethernet/eth.c to see where I got the following */
 427
 428         if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
 429                 /*
 430                  * FIXME: fill in the last byte of the dest ipaddr here to better
 431                  * comply with RFC1051 in "noarp" mode.  For now, always broadcasting
 432                  * will probably at least get packets sent out :)
 433                  */
 434                 pkt->hard.dest = 0;
 435                 return hdr_size;
 436         }
 437         /* otherwise, drop in the dest address */
 438         pkt->hard.dest = daddr;
 439         return hdr_size;
 440 }
 441
 442
 443 static void load_pkt(struct net_device *dev, struct arc_hardware *hard,
 444                      struct arc_rfc1201 *soft, int softlen, int bufnum)
 445 {
 446         struct arcnet_local *lp = dev->priv;
 447         int ofs;
 448
 449         /* assume length <= XMTU: someone should have handled that by now. */
 450
 451         if (softlen > MinTU) {
 452                 hard->offset[0] = 0;
 453                 hard->offset[1] = ofs = 512 - softlen;
 454         } else if (softlen > MTU) {     /* exception packet - add an extra header */
 455                 struct arc_rfc1201 excsoft;
 456
 457                 excsoft.proto = soft->proto;
 458                 excsoft.split_flag = 0xff;
 459                 excsoft.sequence = 0xffff;
 460
 461                 hard->offset[0] = 0;
 462                 ofs = 512 - softlen;
 463                 hard->offset[1] = ofs - RFC1201_HDR_SIZE;
 464                 lp->hw.copy_to_card(dev, bufnum, ofs - RFC1201_HDR_SIZE,
 465                                     &excsoft, RFC1201_HDR_SIZE);
 466         } else
 467                 hard->offset[0] = ofs = 256 - softlen;
 468
 469         lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE);
 470         lp->hw.copy_to_card(dev, bufnum, ofs, soft, softlen);
 471
 472         lp->lastload_dest = hard->dest;
 473 }
 474
 475
 476 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
 477                       int bufnum)
 478 {
 479         struct arcnet_local *lp = dev->priv;
 480         const int maxsegsize = XMTU - RFC1201_HDR_SIZE;
 481         struct Outgoing *out;
 482
 483
 484         BUGMSG(D_DURING, "prepare_tx: txbufs=%d/%d/%d\n",
 485                lp->next_tx, lp->cur_tx, bufnum);
 486
 487         length -= ARC_HDR_SIZE; /* hard header is not included in packet length */
 488         pkt->soft.rfc1201.split_flag = 0;
 489
 490         /* need to do a split packet? */
 491         if (length > XMTU) {
 492                 out = &lp->outgoing;
 493
 494                 out->length = length - RFC1201_HDR_SIZE;
 495                 out->dataleft = lp->outgoing.length;
 496                 out->numsegs = (out->dataleft + maxsegsize - 1) / maxsegsize;
 497                 out->segnum = 0;
 498
 499                 BUGMSG(D_DURING, "rfc1201 prep_tx: ready for %d-segment split "
 500                        "(%d bytes, seq=%d)\n", out->numsegs, out->length,
 501                        pkt->soft.rfc1201.sequence);
 502
 503                 return 0;       /* not done */
 504         }
 505         /* just load the packet into the buffers and send it off */
 506         load_pkt(dev, &pkt->hard, &pkt->soft.rfc1201, length, bufnum);
 507
 508         return 1;               /* done */
 509 }
 510
 511
 512 static int continue_tx(struct net_device *dev, int bufnum)
 513 {
 514         struct arcnet_local *lp = dev->priv;
 515         struct Outgoing *out = &lp->outgoing;
 516         struct arc_hardware *hard = &out->pkt->hard;
 517         struct arc_rfc1201 *soft = &out->pkt->soft.rfc1201, *newsoft;
 518         int maxsegsize = XMTU - RFC1201_HDR_SIZE;
 519         int seglen;
 520
 521         BUGMSG(D_DURING,
 522           "rfc1201 continue_tx: loading segment %d(+1) of %d (seq=%d)\n",
 523                out->segnum, out->numsegs, soft->sequence);
 524
 525         /* the "new" soft header comes right before the data chunk */
 526         newsoft = (struct arc_rfc1201 *)
 527             (out->pkt->soft.raw + out->length - out->dataleft);
 528
 529         if (!out->segnum)       /* first packet; newsoft == soft */
 530                 newsoft->split_flag = ((out->numsegs - 2) << 1) | 1;
 531         else {
 532                 newsoft->split_flag = out->segnum << 1;
 533                 newsoft->proto = soft->proto;
 534                 newsoft->sequence = soft->sequence;
 535         }
 536
 537         seglen = maxsegsize;
 538         if (seglen > out->dataleft)
 539                 seglen = out->dataleft;
 540         out->dataleft -= seglen;
 541
 542         load_pkt(dev, hard, newsoft, seglen + RFC1201_HDR_SIZE, bufnum);
 543
 544         out->segnum++;
 545         if (out->segnum >= out->numsegs)
 546                 return 1;
 547         else
 548                 return 0;
 549 }