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
  27 #define pr_fmt(fmt) "arcnet:" KBUILD_MODNAME ": " fmt
  28
  29 #include <linux/gfp.h>
  30 #include <linux/module.h>
  31 #include <linux/init.h>
  32 #include <linux/if_arp.h>
  33 #include <linux/netdevice.h>
  34 #include <linux/skbuff.h>
  35 #include <linux/arcdevice.h>
  36
  37 MODULE_LICENSE("GPL");
  38
  39 static __be16 type_trans(struct sk_buff *skb, struct net_device *dev);
  40 static void rx(struct net_device *dev, int bufnum,
  41                struct archdr *pkthdr, int length);
  42 static int build_header(struct sk_buff *skb, struct net_device *dev,
  43                         unsigned short type, uint8_t daddr);
  44 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
  45                       int bufnum);
  46 static int continue_tx(struct net_device *dev, int bufnum);
  47
  48 static struct ArcProto rfc1201_proto = {
  49         .suffix         = 'a',
  50         .mtu            = 1500, /* could be more, but some receivers can't handle it... */
  51         .is_ip          = 1,    /* This is for sending IP and ARP packages */
  52         .rx             = rx,
  53         .build_header   = build_header,
  54         .prepare_tx     = prepare_tx,
  55         .continue_tx    = continue_tx,
  56         .ack_tx         = NULL
  57 };
  58
  59 static int __init arcnet_rfc1201_init(void)
  60 {
  61         pr_info("%s\n", "RFC1201 \"standard\" (`a') encapsulation support loaded");
  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 /* 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         arc_printk(D_DURING, dev, "it's an RFC1201 packet (length=%d)\n",
 142                    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                         arc_printk(D_DURING, dev, "compensating for exception packet\n");
 152                 } else {
 153                         arc_printk(D_EXTRA, dev, "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                 arc_printk(D_RX, dev, "incoming is not split (splitflag=%d)\n",
 166                            soft->split_flag);
 167
 168                 if (in->skb) {  /* already assembling one! */
 169                         arc_printk(D_EXTRA, dev, "aborting assembly (seq=%d) for unsplit packet (splitflag=%d, seq=%d)\n",
 170                                    in->sequence, soft->split_flag,
 171                                    soft->sequence);
 172                         lp->rfc1201.aborted_seq = soft->sequence;
 173                         dev_kfree_skb_irq(in->skb);
 174                         dev->stats.rx_errors++;
 175                         dev->stats.rx_missed_errors++;
 176                         in->skb = NULL;
 177                 }
 178                 in->sequence = soft->sequence;
 179
 180                 skb = alloc_skb(length + ARC_HDR_SIZE, GFP_ATOMIC);
 181                 if (!skb) {
 182                         dev->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
 192                  * been copied from the card
 193                  */
 194                 memcpy(pkt, pkthdr, sizeof(struct archdr));
 195                 if (length > sizeof(pkt->soft))
 196                         lp->hw.copy_from_card(dev, bufnum,
 197                                               ofs + sizeof(pkt->soft),
 198                                               pkt->soft.raw + sizeof(pkt->soft),
 199                                               length - sizeof(pkt->soft));
 200
 201                 /* ARP packets have problems when sent from some DOS systems:
 202                  * the source address is always 0!
 203                  * So we take the hardware source addr (which is impossible
 204                  * to fumble) and insert it ourselves.
 205                  */
 206                 if (soft->proto == ARC_P_ARP) {
 207                         struct arphdr *arp = (struct arphdr *)soft->payload;
 208
 209                         /* make sure addresses are the right length */
 210                         if (arp->ar_hln == 1 && arp->ar_pln == 4) {
 211                                 uint8_t *cptr = (uint8_t *)arp + sizeof(struct arphdr);
 212
 213                                 if (!*cptr) {   /* is saddr = 00? */
 214                                         arc_printk(D_EXTRA, dev,
 215                                                    "ARP source address was 00h, set to %02Xh\n",
 216                                                    saddr);
 217                                         dev->stats.rx_crc_errors++;
 218                                         *cptr = saddr;
 219                                 } else {
 220                                         arc_printk(D_DURING, dev, "ARP source address (%Xh) is fine.\n",
 221                                                    *cptr);
 222                                 }
 223                         } else {
 224                                 arc_printk(D_NORMAL, dev, "funny-shaped ARP packet. (%Xh, %Xh)\n",
 225                                            arp->ar_hln, arp->ar_pln);
 226                                 dev->stats.rx_errors++;
 227                                 dev->stats.rx_crc_errors++;
 228                         }
 229                 }
 230                 if (BUGLVL(D_SKB))
 231                         arcnet_dump_skb(dev, skb, "rx");
 232
 233                 skb->protocol = type_trans(skb, dev);
 234                 netif_rx(skb);
 235         } else {                /* split packet */
 236                 /* NOTE: MSDOS ARP packet correction should only need to
 237                  * apply to unsplit packets, since ARP packets are so short.
 238                  *
 239                  * My interpretation of the RFC1201 document is that if a
 240                  * packet is received out of order, the entire assembly
 241                  * process should be aborted.
 242                  *
 243                  * The RFC also mentions "it is possible for successfully
 244                  * received packets to be retransmitted." As of 0.40 all
 245                  * previously received packets are allowed, not just the
 246                  * most recent one.
 247                  *
 248                  * We allow multiple assembly processes, one for each
 249                  * ARCnet card possible on the network.
 250                  * Seems rather like a waste of memory, but there's no
 251                  * other way to be reliable.
 252                  */
 253
 254                 arc_printk(D_RX, dev, "packet is split (splitflag=%d, seq=%d)\n",
 255                            soft->split_flag, in->sequence);
 256
 257                 if (in->skb && in->sequence != soft->sequence) {
 258                         arc_printk(D_EXTRA, dev, "wrong seq number (saddr=%d, expected=%d, seq=%d, splitflag=%d)\n",
 259                                    saddr, in->sequence, soft->sequence,
 260                                    soft->split_flag);
 261                         dev_kfree_skb_irq(in->skb);
 262                         in->skb = NULL;
 263                         dev->stats.rx_errors++;
 264                         dev->stats.rx_missed_errors++;
 265                         in->lastpacket = in->numpackets = 0;
 266                 }
 267                 if (soft->split_flag & 1) {     /* first packet in split */
 268                         arc_printk(D_RX, dev, "brand new splitpacket (splitflag=%d)\n",
 269                                    soft->split_flag);
 270                         if (in->skb) {  /* already assembling one! */
 271                                 arc_printk(D_EXTRA, dev, "aborting previous (seq=%d) assembly (splitflag=%d, seq=%d)\n",
 272                                            in->sequence, soft->split_flag,
 273                                            soft->sequence);
 274                                 dev->stats.rx_errors++;
 275                                 dev->stats.rx_missed_errors++;
 276                                 dev_kfree_skb_irq(in->skb);
 277                         }
 278                         in->sequence = soft->sequence;
 279                         in->numpackets = ((unsigned)soft->split_flag >> 1) + 2;
 280                         in->lastpacket = 1;
 281
 282                         if (in->numpackets > 16) {
 283                                 arc_printk(D_EXTRA, dev, "incoming packet more than 16 segments; dropping. (splitflag=%d)\n",
 284                                            soft->split_flag);
 285                                 lp->rfc1201.aborted_seq = soft->sequence;
 286                                 dev->stats.rx_errors++;
 287                                 dev->stats.rx_length_errors++;
 288                                 return;
 289                         }
 290                         in->skb = skb = alloc_skb(508 * in->numpackets + ARC_HDR_SIZE,
 291                                                   GFP_ATOMIC);
 292                         if (!skb) {
 293                                 arc_printk(D_NORMAL, dev, "(split) memory squeeze, dropping packet.\n");
 294                                 lp->rfc1201.aborted_seq = soft->sequence;
 295                                 dev->stats.rx_dropped++;
 296                                 return;
 297                         }
 298                         skb->dev = dev;
 299                         pkt = (struct archdr *)skb->data;
 300                         soft = &pkt->soft.rfc1201;
 301
 302                         memcpy(pkt, pkthdr, ARC_HDR_SIZE + RFC1201_HDR_SIZE);
 303                         skb_put(skb, ARC_HDR_SIZE + RFC1201_HDR_SIZE);
 304
 305                         soft->split_flag = 0;   /* end result won't be split */
 306                 } else {        /* not first packet */
 307                         int packetnum = ((unsigned)soft->split_flag >> 1) + 1;
 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                                         arc_printk(D_EXTRA, dev, "can't continue split without starting first! (splitflag=%d, seq=%d, aborted=%d)\n",
 315                                                    soft->split_flag,
 316                                                    soft->sequence,
 317                                                    lp->rfc1201.aborted_seq);
 318                                         dev->stats.rx_errors++;
 319                                         dev->stats.rx_missed_errors++;
 320                                 }
 321                                 return;
 322                         }
 323                         in->lastpacket++;
 324                         /* if not the right flag */
 325                         if (packetnum != in->lastpacket) {
 326                                 /* harmless duplicate? ignore. */
 327                                 if (packetnum <= in->lastpacket - 1) {
 328                                         arc_printk(D_EXTRA, dev, "duplicate splitpacket ignored! (splitflag=%d)\n",
 329                                                    soft->split_flag);
 330                                         dev->stats.rx_errors++;
 331                                         dev->stats.rx_frame_errors++;
 332                                         return;
 333                                 }
 334                                 /* "bad" duplicate, kill reassembly */
 335                                 arc_printk(D_EXTRA, dev, "out-of-order splitpacket, reassembly (seq=%d) aborted (splitflag=%d, seq=%d)\n",
 336                                            in->sequence, soft->split_flag,
 337                                            soft->sequence);
 338                                 lp->rfc1201.aborted_seq = soft->sequence;
 339                                 dev_kfree_skb_irq(in->skb);
 340                                 in->skb = NULL;
 341                                 dev->stats.rx_errors++;
 342                                 dev->stats.rx_missed_errors++;
 343                                 in->lastpacket = in->numpackets = 0;
 344                                 return;
 345                         }
 346                         pkt = (struct archdr *)in->skb->data;
 347                         soft = &pkt->soft.rfc1201;
 348                 }
 349
 350                 skb = in->skb;
 351
 352                 lp->hw.copy_from_card(dev, bufnum, ofs + RFC1201_HDR_SIZE,
 353                                       skb->data + skb->len,
 354                                       length - RFC1201_HDR_SIZE);
 355                 skb_put(skb, length - RFC1201_HDR_SIZE);
 356
 357                 /* are we done? */
 358                 if (in->lastpacket == in->numpackets) {
 359                         in->skb = NULL;
 360                         in->lastpacket = in->numpackets = 0;
 361
 362                         arc_printk(D_SKB_SIZE, dev, "skb: received %d bytes from %02X (unsplit)\n",
 363                                    skb->len, pkt->hard.source);
 364                         arc_printk(D_SKB_SIZE, dev, "skb: received %d bytes from %02X (split)\n",
 365                                    skb->len, pkt->hard.source);
 366                         if (BUGLVL(D_SKB))
 367                                 arcnet_dump_skb(dev, skb, "rx");
 368
 369                         skb->protocol = type_trans(skb, dev);
 370                         netif_rx(skb);
 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 = netdev_priv(dev);
 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                 arc_printk(D_NORMAL, dev, "RFC1201: I don't understand protocol %d (%Xh)\n",
 408                            type, type);
 409                 dev->stats.tx_errors++;
 410                 dev->stats.tx_aborted_errors++;
 411                 return 0;
 412         }
 413
 414         /* Set the source hardware address.
 415          *
 416          * This is pretty pointless for most purposes, but it can help in
 417          * debugging.  ARCnet does not allow us to change the source address
 418          * in the actual packet sent.
 419          */
 420         pkt->hard.source = *dev->dev_addr;
 421
 422         soft->sequence = htons(lp->rfc1201.sequence++);
 423         soft->split_flag = 0;   /* split packets are done elsewhere */
 424
 425         /* see linux/net/ethernet/eth.c to see where I got the following */
 426
 427         if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
 428                 /* FIXME: fill in the last byte of the dest ipaddr here
 429                  * to better comply with RFC1051 in "noarp" mode.
 430                  * For now, always broadcasting will probably at least get
 431                  * packets sent out :)
 432                  */
 433                 pkt->hard.dest = 0;
 434                 return hdr_size;
 435         }
 436         /* otherwise, drop in the dest address */
 437         pkt->hard.dest = daddr;
 438         return hdr_size;
 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 = netdev_priv(dev);
 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 = htons(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
 468         lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE);
 469         lp->hw.copy_to_card(dev, bufnum, ofs, soft, softlen);
 470
 471         lp->lastload_dest = hard->dest;
 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 = netdev_priv(dev);
 478         const int maxsegsize = XMTU - RFC1201_HDR_SIZE;
 479         struct Outgoing *out;
 480
 481         arc_printk(D_DURING, dev, "prepare_tx: txbufs=%d/%d/%d\n",
 482                    lp->next_tx, lp->cur_tx, bufnum);
 483
 484         /* hard header is not included in packet length */
 485         length -= ARC_HDR_SIZE;
 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                 arc_printk(D_DURING, dev, "rfc1201 prep_tx: ready for %d-segment split (%d bytes, seq=%d)\n",
 498                            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 static int continue_tx(struct net_device *dev, int bufnum)
 510 {
 511         struct arcnet_local *lp = netdev_priv(dev);
 512         struct Outgoing *out = &lp->outgoing;
 513         struct arc_hardware *hard = &out->pkt->hard;
 514         struct arc_rfc1201 *soft = &out->pkt->soft.rfc1201, *newsoft;
 515         int maxsegsize = XMTU - RFC1201_HDR_SIZE;
 516         int seglen;
 517
 518         arc_printk(D_DURING, dev,
 519                    "rfc1201 continue_tx: loading segment %d(+1) of %d (seq=%d)\n",
 520                    out->segnum, out->numsegs, soft->sequence);
 521
 522         /* the "new" soft header comes right before the data chunk */
 523         newsoft = (struct arc_rfc1201 *)
 524             (out->pkt->soft.raw + out->length - out->dataleft);
 525
 526         if (!out->segnum)       /* first packet; newsoft == soft */
 527                 newsoft->split_flag = ((out->numsegs - 2) << 1) | 1;
 528         else {
 529                 newsoft->split_flag = out->segnum << 1;
 530                 newsoft->proto = soft->proto;
 531                 newsoft->sequence = soft->sequence;
 532         }
 533
 534         seglen = maxsegsize;
 535         if (seglen > out->dataleft)
 536                 seglen = out->dataleft;
 537         out->dataleft -= seglen;
 538
 539         load_pkt(dev, hard, newsoft, seglen + RFC1201_HDR_SIZE, bufnum);
 540
 541         out->segnum++;
 542         if (out->segnum >= out->numsegs)
 543                 return 1;
 544         else
 545                 return 0;
 546 }