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
  36 #include "arcdevice.h"
  37
  38 MODULE_LICENSE("GPL");
  39
  40 static __be16 type_trans(struct sk_buff *skb, struct net_device *dev);
  41 static void rx(struct net_device *dev, int bufnum,
  42                struct archdr *pkthdr, int length);
  43 static int build_header(struct sk_buff *skb, struct net_device *dev,
  44                         unsigned short type, uint8_t daddr);
  45 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
  46                       int bufnum);
  47 static int continue_tx(struct net_device *dev, int bufnum);
  48
  49 static struct ArcProto rfc1201_proto = {
  50         .suffix         = 'a',
  51         .mtu            = 1500, /* could be more, but some receivers can't handle it... */
  52         .is_ip          = 1,    /* This is for sending IP and ARP packages */
  53         .rx             = rx,
  54         .build_header   = build_header,
  55         .prepare_tx     = prepare_tx,
  56         .continue_tx    = continue_tx,
  57         .ack_tx         = NULL
  58 };
  59
  60 static int __init arcnet_rfc1201_init(void)
  61 {
  62         pr_info("%s\n", "RFC1201 \"standard\" (`a') encapsulation support loaded");
  63
  64         arc_proto_map[ARC_P_IP]
  65             = arc_proto_map[ARC_P_IPV6]
  66             = arc_proto_map[ARC_P_ARP]
  67             = arc_proto_map[ARC_P_RARP]
  68             = arc_proto_map[ARC_P_IPX]
  69             = arc_proto_map[ARC_P_NOVELL_EC]
  70             = &rfc1201_proto;
  71
  72         /* if someone else already owns the broadcast, we won't take it */
  73         if (arc_bcast_proto == arc_proto_default)
  74                 arc_bcast_proto = &rfc1201_proto;
  75
  76         return 0;
  77 }
  78
  79 static void __exit arcnet_rfc1201_exit(void)
  80 {
  81         arcnet_unregister_proto(&rfc1201_proto);
  82 }
  83
  84 module_init(arcnet_rfc1201_init);
  85 module_exit(arcnet_rfc1201_exit);
  86
  87 /* Determine a packet's protocol ID.
  88  *
  89  * With ARCnet we have to convert everything to Ethernet-style stuff.
  90  */
  91 static __be16 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         int hdr_size = ARC_HDR_SIZE + RFC1201_HDR_SIZE;
  96
  97         /* Pull off the arcnet header. */
  98         skb_reset_mac_header(skb);
  99         skb_pull(skb, hdr_size);
 100
 101         if (pkt->hard.dest == 0) {
 102                 skb->pkt_type = PACKET_BROADCAST;
 103         } else if (dev->flags & IFF_PROMISC) {
 104                 /* if we're not sending to ourselves :) */
 105                 if (pkt->hard.dest != dev->dev_addr[0])
 106                         skb->pkt_type = PACKET_OTHERHOST;
 107         }
 108         /* now return the protocol number */
 109         switch (soft->proto) {
 110         case ARC_P_IP:
 111                 return htons(ETH_P_IP);
 112         case ARC_P_IPV6:
 113                 return htons(ETH_P_IPV6);
 114         case ARC_P_ARP:
 115                 return htons(ETH_P_ARP);
 116         case ARC_P_RARP:
 117                 return htons(ETH_P_RARP);
 118
 119         case ARC_P_IPX:
 120         case ARC_P_NOVELL_EC:
 121                 return htons(ETH_P_802_3);
 122         default:
 123                 dev->stats.rx_errors++;
 124                 dev->stats.rx_crc_errors++;
 125                 return 0;
 126         }
 127
 128         return htons(ETH_P_IP);
 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 = netdev_priv(dev);
 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         arc_printk(D_DURING, dev, "it's an RFC1201 packet (length=%d)\n",
 143                    length);
 144
 145         if (length >= MinTU)
 146                 ofs = 512 - length;
 147         else
 148                 ofs = 256 - length;
 149
 150         if (soft->split_flag == 0xFF) {         /* Exception Packet */
 151                 if (length >= 4 + RFC1201_HDR_SIZE) {
 152                         arc_printk(D_DURING, dev, "compensating for exception packet\n");
 153                 } else {
 154                         arc_printk(D_EXTRA, dev, "short RFC1201 exception packet from %02Xh",
 155                                    saddr);
 156                         return;
 157                 }
 158
 159                 /* skip over 4-byte junkola */
 160                 length -= 4;
 161                 ofs += 4;
 162                 lp->hw.copy_from_card(dev, bufnum, 512 - length,
 163                                       soft, sizeof(pkt->soft));
 164         }
 165         if (!soft->split_flag) {        /* not split */
 166                 arc_printk(D_RX, dev, "incoming is not split (splitflag=%d)\n",
 167                            soft->split_flag);
 168
 169                 if (in->skb) {  /* already assembling one! */
 170                         arc_printk(D_EXTRA, dev, "aborting assembly (seq=%d) for unsplit packet (splitflag=%d, seq=%d)\n",
 171                                    in->sequence, soft->split_flag,
 172                                    soft->sequence);
 173                         lp->rfc1201.aborted_seq = soft->sequence;
 174                         dev_kfree_skb_irq(in->skb);
 175                         dev->stats.rx_errors++;
 176                         dev->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) {
 183                         dev->stats.rx_dropped++;
 184                         return;
 185                 }
 186                 skb_put(skb, length + ARC_HDR_SIZE);
 187                 skb->dev = dev;
 188
 189                 pkt = (struct archdr *)skb->data;
 190                 soft = &pkt->soft.rfc1201;
 191
 192                 /* up to sizeof(pkt->soft) has already
 193                  * been copied from the card
 194                  */
 195                 memcpy(pkt, pkthdr, sizeof(struct archdr));
 196                 if (length > sizeof(pkt->soft))
 197                         lp->hw.copy_from_card(dev, bufnum,
 198                                               ofs + sizeof(pkt->soft),
 199                                               pkt->soft.raw + sizeof(pkt->soft),
 200                                               length - sizeof(pkt->soft));
 201
 202                 /* ARP packets have problems when sent from some DOS systems:
 203                  * the source address is always 0!
 204                  * So we take the hardware source addr (which is impossible
 205                  * to fumble) and insert it ourselves.
 206                  */
 207                 if (soft->proto == ARC_P_ARP) {
 208                         struct arphdr *arp = (struct arphdr *)soft->payload;
 209
 210                         /* make sure addresses are the right length */
 211                         if (arp->ar_hln == 1 && arp->ar_pln == 4) {
 212                                 uint8_t *cptr = (uint8_t *)arp + sizeof(struct arphdr);
 213
 214                                 if (!*cptr) {   /* is saddr = 00? */
 215                                         arc_printk(D_EXTRA, dev,
 216                                                    "ARP source address was 00h, set to %02Xh\n",
 217                                                    saddr);
 218                                         dev->stats.rx_crc_errors++;
 219                                         *cptr = saddr;
 220                                 } else {
 221                                         arc_printk(D_DURING, dev, "ARP source address (%Xh) is fine.\n",
 222                                                    *cptr);
 223                                 }
 224                         } else {
 225                                 arc_printk(D_NORMAL, dev, "funny-shaped ARP packet. (%Xh, %Xh)\n",
 226                                            arp->ar_hln, arp->ar_pln);
 227                                 dev->stats.rx_errors++;
 228                                 dev->stats.rx_crc_errors++;
 229                         }
 230                 }
 231                 if (BUGLVL(D_SKB))
 232                         arcnet_dump_skb(dev, skb, "rx");
 233
 234                 skb->protocol = type_trans(skb, dev);
 235                 netif_rx(skb);
 236         } else {                /* split packet */
 237                 /* NOTE: MSDOS ARP packet correction should only need to
 238                  * apply to unsplit packets, since ARP packets are so short.
 239                  *
 240                  * My interpretation of the RFC1201 document is that if a
 241                  * packet is received out of order, the entire assembly
 242                  * process should be aborted.
 243                  *
 244                  * The RFC also mentions "it is possible for successfully
 245                  * received packets to be retransmitted." As of 0.40 all
 246                  * previously received packets are allowed, not just the
 247                  * most recent one.
 248                  *
 249                  * We allow multiple assembly processes, one for each
 250                  * ARCnet card possible on the network.
 251                  * Seems rather like a waste of memory, but there's no
 252                  * other way to be reliable.
 253                  */
 254
 255                 arc_printk(D_RX, dev, "packet is split (splitflag=%d, seq=%d)\n",
 256                            soft->split_flag, in->sequence);
 257
 258                 if (in->skb && in->sequence != soft->sequence) {
 259                         arc_printk(D_EXTRA, dev, "wrong seq number (saddr=%d, expected=%d, seq=%d, splitflag=%d)\n",
 260                                    saddr, in->sequence, soft->sequence,
 261                                    soft->split_flag);
 262                         dev_kfree_skb_irq(in->skb);
 263                         in->skb = NULL;
 264                         dev->stats.rx_errors++;
 265                         dev->stats.rx_missed_errors++;
 266                         in->lastpacket = in->numpackets = 0;
 267                 }
 268                 if (soft->split_flag & 1) {     /* first packet in split */
 269                         arc_printk(D_RX, dev, "brand new splitpacket (splitflag=%d)\n",
 270                                    soft->split_flag);
 271                         if (in->skb) {  /* already assembling one! */
 272                                 arc_printk(D_EXTRA, dev, "aborting previous (seq=%d) assembly (splitflag=%d, seq=%d)\n",
 273                                            in->sequence, soft->split_flag,
 274                                            soft->sequence);
 275                                 dev->stats.rx_errors++;
 276                                 dev->stats.rx_missed_errors++;
 277                                 dev_kfree_skb_irq(in->skb);
 278                         }
 279                         in->sequence = soft->sequence;
 280                         in->numpackets = ((unsigned)soft->split_flag >> 1) + 2;
 281                         in->lastpacket = 1;
 282
 283                         if (in->numpackets > 16) {
 284                                 arc_printk(D_EXTRA, dev, "incoming packet more than 16 segments; dropping. (splitflag=%d)\n",
 285                                            soft->split_flag);
 286                                 lp->rfc1201.aborted_seq = soft->sequence;
 287                                 dev->stats.rx_errors++;
 288                                 dev->stats.rx_length_errors++;
 289                                 return;
 290                         }
 291                         in->skb = skb = alloc_skb(508 * in->numpackets + ARC_HDR_SIZE,
 292                                                   GFP_ATOMIC);
 293                         if (!skb) {
 294                                 arc_printk(D_NORMAL, dev, "(split) memory squeeze, dropping packet.\n");
 295                                 lp->rfc1201.aborted_seq = soft->sequence;
 296                                 dev->stats.rx_dropped++;
 297                                 return;
 298                         }
 299                         skb->dev = dev;
 300                         pkt = (struct archdr *)skb->data;
 301                         soft = &pkt->soft.rfc1201;
 302
 303                         memcpy(pkt, pkthdr, ARC_HDR_SIZE + RFC1201_HDR_SIZE);
 304                         skb_put(skb, ARC_HDR_SIZE + RFC1201_HDR_SIZE);
 305
 306                         soft->split_flag = 0;   /* end result won't be split */
 307                 } else {        /* not first packet */
 308                         int packetnum = ((unsigned)soft->split_flag >> 1) + 1;
 309
 310                         /* if we're not assembling, there's no point trying to
 311                          * continue.
 312                          */
 313                         if (!in->skb) {
 314                                 if (lp->rfc1201.aborted_seq != soft->sequence) {
 315                                         arc_printk(D_EXTRA, dev, "can't continue split without starting first! (splitflag=%d, seq=%d, aborted=%d)\n",
 316                                                    soft->split_flag,
 317                                                    soft->sequence,
 318                                                    lp->rfc1201.aborted_seq);
 319                                         dev->stats.rx_errors++;
 320                                         dev->stats.rx_missed_errors++;
 321                                 }
 322                                 return;
 323                         }
 324                         in->lastpacket++;
 325                         /* if not the right flag */
 326                         if (packetnum != in->lastpacket) {
 327                                 /* harmless duplicate? ignore. */
 328                                 if (packetnum <= in->lastpacket - 1) {
 329                                         arc_printk(D_EXTRA, dev, "duplicate splitpacket ignored! (splitflag=%d)\n",
 330                                                    soft->split_flag);
 331                                         dev->stats.rx_errors++;
 332                                         dev->stats.rx_frame_errors++;
 333                                         return;
 334                                 }
 335                                 /* "bad" duplicate, kill reassembly */
 336                                 arc_printk(D_EXTRA, dev, "out-of-order splitpacket, reassembly (seq=%d) aborted (splitflag=%d, seq=%d)\n",
 337                                            in->sequence, soft->split_flag,
 338                                            soft->sequence);
 339                                 lp->rfc1201.aborted_seq = soft->sequence;
 340                                 dev_kfree_skb_irq(in->skb);
 341                                 in->skb = NULL;
 342                                 dev->stats.rx_errors++;
 343                                 dev->stats.rx_missed_errors++;
 344                                 in->lastpacket = in->numpackets = 0;
 345                                 return;
 346                         }
 347                         pkt = (struct archdr *)in->skb->data;
 348                         soft = &pkt->soft.rfc1201;
 349                 }
 350
 351                 skb = in->skb;
 352
 353                 lp->hw.copy_from_card(dev, bufnum, ofs + RFC1201_HDR_SIZE,
 354                                       skb->data + skb->len,
 355                                       length - RFC1201_HDR_SIZE);
 356                 skb_put(skb, length - RFC1201_HDR_SIZE);
 357
 358                 /* are we done? */
 359                 if (in->lastpacket == in->numpackets) {
 360                         in->skb = NULL;
 361                         in->lastpacket = in->numpackets = 0;
 362
 363                         arc_printk(D_SKB_SIZE, dev, "skb: received %d bytes from %02X (unsplit)\n",
 364                                    skb->len, pkt->hard.source);
 365                         arc_printk(D_SKB_SIZE, dev, "skb: received %d bytes from %02X (split)\n",
 366                                    skb->len, pkt->hard.source);
 367                         if (BUGLVL(D_SKB))
 368                                 arcnet_dump_skb(dev, skb, "rx");
 369
 370                         skb->protocol = type_trans(skb, dev);
 371                         netif_rx(skb);
 372                 }
 373         }
 374 }
 375
 376 /* Create the ARCnet hard/soft headers for RFC1201. */
 377 static int build_header(struct sk_buff *skb, struct net_device *dev,
 378                         unsigned short type, uint8_t daddr)
 379 {
 380         struct arcnet_local *lp = netdev_priv(dev);
 381         int hdr_size = ARC_HDR_SIZE + RFC1201_HDR_SIZE;
 382         struct archdr *pkt = skb_push(skb, hdr_size);
 383         struct arc_rfc1201 *soft = &pkt->soft.rfc1201;
 384
 385         /* set the protocol ID according to RFC1201 */
 386         switch (type) {
 387         case ETH_P_IP:
 388                 soft->proto = ARC_P_IP;
 389                 break;
 390         case ETH_P_IPV6:
 391                 soft->proto = ARC_P_IPV6;
 392                 break;
 393         case ETH_P_ARP:
 394                 soft->proto = ARC_P_ARP;
 395                 break;
 396         case ETH_P_RARP:
 397                 soft->proto = ARC_P_RARP;
 398                 break;
 399         case ETH_P_IPX:
 400         case ETH_P_802_3:
 401         case ETH_P_802_2:
 402                 soft->proto = ARC_P_IPX;
 403                 break;
 404         case ETH_P_ATALK:
 405                 soft->proto = ARC_P_ATALK;
 406                 break;
 407         default:
 408                 arc_printk(D_NORMAL, dev, "RFC1201: I don't understand protocol %d (%Xh)\n",
 409                            type, type);
 410                 dev->stats.tx_errors++;
 411                 dev->stats.tx_aborted_errors++;
 412                 return 0;
 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
 419          * in 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                 /* FIXME: fill in the last byte of the dest ipaddr here
 430                  * to better comply with RFC1051 in "noarp" mode.
 431                  * For now, always broadcasting will probably at least get
 432                  * 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 static void load_pkt(struct net_device *dev, struct arc_hardware *hard,
 443                      struct arc_rfc1201 *soft, int softlen, int bufnum)
 444 {
 445         struct arcnet_local *lp = netdev_priv(dev);
 446         int ofs;
 447
 448         /* assume length <= XMTU: someone should have handled that by now. */
 449
 450         if (softlen > MinTU) {
 451                 hard->offset[0] = 0;
 452                 hard->offset[1] = ofs = 512 - softlen;
 453         } else if (softlen > MTU) {     /* exception packet - add an extra header */
 454                 struct arc_rfc1201 excsoft;
 455
 456                 excsoft.proto = soft->proto;
 457                 excsoft.split_flag = 0xff;
 458                 excsoft.sequence = htons(0xffff);
 459
 460                 hard->offset[0] = 0;
 461                 ofs = 512 - softlen;
 462                 hard->offset[1] = ofs - RFC1201_HDR_SIZE;
 463                 lp->hw.copy_to_card(dev, bufnum, ofs - RFC1201_HDR_SIZE,
 464                                     &excsoft, RFC1201_HDR_SIZE);
 465         } else {
 466                 hard->offset[0] = ofs = 256 - softlen;
 467         }
 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 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
 476                       int bufnum)
 477 {
 478         struct arcnet_local *lp = netdev_priv(dev);
 479         const int maxsegsize = XMTU - RFC1201_HDR_SIZE;
 480         struct Outgoing *out;
 481
 482         arc_printk(D_DURING, dev, "prepare_tx: txbufs=%d/%d/%d\n",
 483                    lp->next_tx, lp->cur_tx, bufnum);
 484
 485         /* hard header is not included in packet length */
 486         length -= ARC_HDR_SIZE;
 487         pkt->soft.rfc1201.split_flag = 0;
 488
 489         /* need to do a split packet? */
 490         if (length > XMTU) {
 491                 out = &lp->outgoing;
 492
 493                 out->length = length - RFC1201_HDR_SIZE;
 494                 out->dataleft = lp->outgoing.length;
 495                 out->numsegs = (out->dataleft + maxsegsize - 1) / maxsegsize;
 496                 out->segnum = 0;
 497
 498                 arc_printk(D_DURING, dev, "rfc1201 prep_tx: ready for %d-segment split (%d bytes, seq=%d)\n",
 499                            out->numsegs, out->length,
 500                            pkt->soft.rfc1201.sequence);
 501
 502                 return 0;       /* not done */
 503         }
 504         /* just load the packet into the buffers and send it off */
 505         load_pkt(dev, &pkt->hard, &pkt->soft.rfc1201, length, bufnum);
 506
 507         return 1;               /* done */
 508 }
 509
 510 static int continue_tx(struct net_device *dev, int bufnum)
 511 {
 512         struct arcnet_local *lp = netdev_priv(dev);
 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         arc_printk(D_DURING, dev,
 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 }