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_DESCRIPTION("ARCNet packet format (RFC 1201) module");
  39 MODULE_LICENSE("GPL");
  40
  41 static __be16 type_trans(struct sk_buff *skb, struct net_device *dev);
  42 static void rx(struct net_device *dev, int bufnum,
  43                struct archdr *pkthdr, int length);
  44 static int build_header(struct sk_buff *skb, struct net_device *dev,
  45                         unsigned short type, uint8_t daddr);
  46 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
  47                       int bufnum);
  48 static int continue_tx(struct net_device *dev, int bufnum);
  49
  50 static struct ArcProto rfc1201_proto = {
  51         .suffix         = 'a',
  52         .mtu            = 1500, /* could be more, but some receivers can't handle it... */
  53         .is_ip          = 1,    /* This is for sending IP and ARP packages */
  54         .rx             = rx,
  55         .build_header   = build_header,
  56         .prepare_tx     = prepare_tx,
  57         .continue_tx    = continue_tx,
  58         .ack_tx         = NULL
  59 };
  60
  61 static int __init arcnet_rfc1201_init(void)
  62 {
  63         pr_info("%s\n", "RFC1201 \"standard\" (`a') encapsulation support loaded");
  64
  65         arc_proto_map[ARC_P_IP]
  66             = arc_proto_map[ARC_P_IPV6]
  67             = arc_proto_map[ARC_P_ARP]
  68             = arc_proto_map[ARC_P_RARP]
  69             = arc_proto_map[ARC_P_IPX]
  70             = arc_proto_map[ARC_P_NOVELL_EC]
  71             = &rfc1201_proto;
  72
  73         /* if someone else already owns the broadcast, we won't take it */
  74         if (arc_bcast_proto == arc_proto_default)
  75                 arc_bcast_proto = &rfc1201_proto;
  76
  77         return 0;
  78 }
  79
  80 static void __exit arcnet_rfc1201_exit(void)
  81 {
  82         arcnet_unregister_proto(&rfc1201_proto);
  83 }
  84
  85 module_init(arcnet_rfc1201_init);
  86 module_exit(arcnet_rfc1201_exit);
  87
  88 /* Determine a packet's protocol ID.
  89  *
  90  * With ARCnet we have to convert everything to Ethernet-style stuff.
  91  */
  92 static __be16 type_trans(struct sk_buff *skb, struct net_device *dev)
  93 {
  94         struct archdr *pkt = (struct archdr *)skb->data;
  95         struct arc_rfc1201 *soft = &pkt->soft.rfc1201;
  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                 dev->stats.rx_errors++;
 125                 dev->stats.rx_crc_errors++;
 126                 return 0;
 127         }
 128
 129         return htons(ETH_P_IP);
 130 }
 131
 132 /* packet receiver */
 133 static void rx(struct net_device *dev, int bufnum,
 134                struct archdr *pkthdr, int length)
 135 {
 136         struct arcnet_local *lp = netdev_priv(dev);
 137         struct sk_buff *skb;
 138         struct archdr *pkt = pkthdr;
 139         struct arc_rfc1201 *soft = &pkthdr->soft.rfc1201;
 140         int saddr = pkt->hard.source, ofs;
 141         struct Incoming *in = &lp->rfc1201.incoming[saddr];
 142
 143         arc_printk(D_DURING, dev, "it's an RFC1201 packet (length=%d)\n",
 144                    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                         arc_printk(D_DURING, dev, "compensating for exception packet\n");
 154                 } else {
 155                         arc_printk(D_EXTRA, dev, "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                 arc_printk(D_RX, dev, "incoming is not split (splitflag=%d)\n",
 168                            soft->split_flag);
 169
 170                 if (in->skb) {  /* already assembling one! */
 171                         arc_printk(D_EXTRA, dev, "aborting assembly (seq=%d) for unsplit packet (splitflag=%d, seq=%d)\n",
 172                                    in->sequence, soft->split_flag,
 173                                    soft->sequence);
 174                         lp->rfc1201.aborted_seq = soft->sequence;
 175                         dev_kfree_skb_irq(in->skb);
 176                         dev->stats.rx_errors++;
 177                         dev->stats.rx_missed_errors++;
 178                         in->skb = NULL;
 179                 }
 180                 in->sequence = soft->sequence;
 181
 182                 skb = alloc_skb(length + ARC_HDR_SIZE, GFP_ATOMIC);
 183                 if (!skb) {
 184                         dev->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
 194                  * been copied from the card
 195                  */
 196                 memcpy(pkt, pkthdr, sizeof(struct archdr));
 197                 if (length > sizeof(pkt->soft))
 198                         lp->hw.copy_from_card(dev, bufnum,
 199                                               ofs + sizeof(pkt->soft),
 200                                               pkt->soft.raw + sizeof(pkt->soft),
 201                                               length - sizeof(pkt->soft));
 202
 203                 /* ARP packets have problems when sent from some DOS systems:
 204                  * the source address is always 0!
 205                  * So we take the hardware source addr (which is impossible
 206                  * to fumble) and insert it ourselves.
 207                  */
 208                 if (soft->proto == ARC_P_ARP) {
 209                         struct arphdr *arp = (struct arphdr *)soft->payload;
 210
 211                         /* make sure addresses are the right length */
 212                         if (arp->ar_hln == 1 && arp->ar_pln == 4) {
 213                                 uint8_t *cptr = (uint8_t *)arp + sizeof(struct arphdr);
 214
 215                                 if (!*cptr) {   /* is saddr = 00? */
 216                                         arc_printk(D_EXTRA, dev,
 217                                                    "ARP source address was 00h, set to %02Xh\n",
 218                                                    saddr);
 219                                         dev->stats.rx_crc_errors++;
 220                                         *cptr = saddr;
 221                                 } else {
 222                                         arc_printk(D_DURING, dev, "ARP source address (%Xh) is fine.\n",
 223                                                    *cptr);
 224                                 }
 225                         } else {
 226                                 arc_printk(D_NORMAL, dev, "funny-shaped ARP packet. (%Xh, %Xh)\n",
 227                                            arp->ar_hln, arp->ar_pln);
 228                                 dev->stats.rx_errors++;
 229                                 dev->stats.rx_crc_errors++;
 230                         }
 231                 }
 232                 if (BUGLVL(D_SKB))
 233                         arcnet_dump_skb(dev, skb, "rx");
 234
 235                 skb->protocol = type_trans(skb, dev);
 236                 netif_rx(skb);
 237         } else {                /* split packet */
 238                 /* NOTE: MSDOS ARP packet correction should only need to
 239                  * apply to unsplit packets, since ARP packets are so short.
 240                  *
 241                  * My interpretation of the RFC1201 document is that if a
 242                  * packet is received out of order, the entire assembly
 243                  * process should be aborted.
 244                  *
 245                  * The RFC also mentions "it is possible for successfully
 246                  * received packets to be retransmitted." As of 0.40 all
 247                  * previously received packets are allowed, not just the
 248                  * most recent one.
 249                  *
 250                  * We allow multiple assembly processes, one for each
 251                  * ARCnet card possible on the network.
 252                  * Seems rather like a waste of memory, but there's no
 253                  * other way to be reliable.
 254                  */
 255
 256                 arc_printk(D_RX, dev, "packet is split (splitflag=%d, seq=%d)\n",
 257                            soft->split_flag, in->sequence);
 258
 259                 if (in->skb && in->sequence != soft->sequence) {
 260                         arc_printk(D_EXTRA, dev, "wrong seq number (saddr=%d, expected=%d, seq=%d, splitflag=%d)\n",
 261                                    saddr, in->sequence, soft->sequence,
 262                                    soft->split_flag);
 263                         dev_kfree_skb_irq(in->skb);
 264                         in->skb = NULL;
 265                         dev->stats.rx_errors++;
 266                         dev->stats.rx_missed_errors++;
 267                         in->lastpacket = in->numpackets = 0;
 268                 }
 269                 if (soft->split_flag & 1) {     /* first packet in split */
 270                         arc_printk(D_RX, dev, "brand new splitpacket (splitflag=%d)\n",
 271                                    soft->split_flag);
 272                         if (in->skb) {  /* already assembling one! */
 273                                 arc_printk(D_EXTRA, dev, "aborting previous (seq=%d) assembly (splitflag=%d, seq=%d)\n",
 274                                            in->sequence, soft->split_flag,
 275                                            soft->sequence);
 276                                 dev->stats.rx_errors++;
 277                                 dev->stats.rx_missed_errors++;
 278                                 dev_kfree_skb_irq(in->skb);
 279                         }
 280                         in->sequence = soft->sequence;
 281                         in->numpackets = ((unsigned)soft->split_flag >> 1) + 2;
 282                         in->lastpacket = 1;
 283
 284                         if (in->numpackets > 16) {
 285                                 arc_printk(D_EXTRA, dev, "incoming packet more than 16 segments; dropping. (splitflag=%d)\n",
 286                                            soft->split_flag);
 287                                 lp->rfc1201.aborted_seq = soft->sequence;
 288                                 dev->stats.rx_errors++;
 289                                 dev->stats.rx_length_errors++;
 290                                 return;
 291                         }
 292                         in->skb = skb = alloc_skb(508 * in->numpackets + ARC_HDR_SIZE,
 293                                                   GFP_ATOMIC);
 294                         if (!skb) {
 295                                 arc_printk(D_NORMAL, dev, "(split) memory squeeze, dropping packet.\n");
 296                                 lp->rfc1201.aborted_seq = soft->sequence;
 297                                 dev->stats.rx_dropped++;
 298                                 return;
 299                         }
 300                         skb->dev = dev;
 301                         pkt = (struct archdr *)skb->data;
 302                         soft = &pkt->soft.rfc1201;
 303
 304                         memcpy(pkt, pkthdr, ARC_HDR_SIZE + RFC1201_HDR_SIZE);
 305                         skb_put(skb, ARC_HDR_SIZE + RFC1201_HDR_SIZE);
 306
 307                         soft->split_flag = 0;   /* end result won't be split */
 308                 } else {        /* not first packet */
 309                         int packetnum = ((unsigned)soft->split_flag >> 1) + 1;
 310
 311                         /* if we're not assembling, there's no point trying to
 312                          * continue.
 313                          */
 314                         if (!in->skb) {
 315                                 if (lp->rfc1201.aborted_seq != soft->sequence) {
 316                                         arc_printk(D_EXTRA, dev, "can't continue split without starting first! (splitflag=%d, seq=%d, aborted=%d)\n",
 317                                                    soft->split_flag,
 318                                                    soft->sequence,
 319                                                    lp->rfc1201.aborted_seq);
 320                                         dev->stats.rx_errors++;
 321                                         dev->stats.rx_missed_errors++;
 322                                 }
 323                                 return;
 324                         }
 325                         in->lastpacket++;
 326                         /* if not the right flag */
 327                         if (packetnum != in->lastpacket) {
 328                                 /* harmless duplicate? ignore. */
 329                                 if (packetnum <= in->lastpacket - 1) {
 330                                         arc_printk(D_EXTRA, dev, "duplicate splitpacket ignored! (splitflag=%d)\n",
 331                                                    soft->split_flag);
 332                                         dev->stats.rx_errors++;
 333                                         dev->stats.rx_frame_errors++;
 334                                         return;
 335                                 }
 336                                 /* "bad" duplicate, kill reassembly */
 337                                 arc_printk(D_EXTRA, dev, "out-of-order splitpacket, reassembly (seq=%d) aborted (splitflag=%d, seq=%d)\n",
 338                                            in->sequence, soft->split_flag,
 339                                            soft->sequence);
 340                                 lp->rfc1201.aborted_seq = soft->sequence;
 341                                 dev_kfree_skb_irq(in->skb);
 342                                 in->skb = NULL;
 343                                 dev->stats.rx_errors++;
 344                                 dev->stats.rx_missed_errors++;
 345                                 in->lastpacket = in->numpackets = 0;
 346                                 return;
 347                         }
 348                         pkt = (struct archdr *)in->skb->data;
 349                         soft = &pkt->soft.rfc1201;
 350                 }
 351
 352                 skb = in->skb;
 353
 354                 lp->hw.copy_from_card(dev, bufnum, ofs + RFC1201_HDR_SIZE,
 355                                       skb->data + skb->len,
 356                                       length - RFC1201_HDR_SIZE);
 357                 skb_put(skb, length - RFC1201_HDR_SIZE);
 358
 359                 /* are we done? */
 360                 if (in->lastpacket == in->numpackets) {
 361                         in->skb = NULL;
 362                         in->lastpacket = in->numpackets = 0;
 363
 364                         arc_printk(D_SKB_SIZE, dev, "skb: received %d bytes from %02X (unsplit)\n",
 365                                    skb->len, pkt->hard.source);
 366                         arc_printk(D_SKB_SIZE, dev, "skb: received %d bytes from %02X (split)\n",
 367                                    skb->len, pkt->hard.source);
 368                         if (BUGLVL(D_SKB))
 369                                 arcnet_dump_skb(dev, skb, "rx");
 370
 371                         skb->protocol = type_trans(skb, dev);
 372                         netif_rx(skb);
 373                 }
 374         }
 375 }
 376
 377 /* Create the ARCnet hard/soft headers for RFC1201. */
 378 static int build_header(struct sk_buff *skb, struct net_device *dev,
 379                         unsigned short type, uint8_t daddr)
 380 {
 381         struct arcnet_local *lp = netdev_priv(dev);
 382         int hdr_size = ARC_HDR_SIZE + RFC1201_HDR_SIZE;
 383         struct archdr *pkt = skb_push(skb, hdr_size);
 384         struct arc_rfc1201 *soft = &pkt->soft.rfc1201;
 385
 386         /* set the protocol ID according to RFC1201 */
 387         switch (type) {
 388         case ETH_P_IP:
 389                 soft->proto = ARC_P_IP;
 390                 break;
 391         case ETH_P_IPV6:
 392                 soft->proto = ARC_P_IPV6;
 393                 break;
 394         case ETH_P_ARP:
 395                 soft->proto = ARC_P_ARP;
 396                 break;
 397         case ETH_P_RARP:
 398                 soft->proto = ARC_P_RARP;
 399                 break;
 400         case ETH_P_IPX:
 401         case ETH_P_802_3:
 402         case ETH_P_802_2:
 403                 soft->proto = ARC_P_IPX;
 404                 break;
 405         case ETH_P_ATALK:
 406                 soft->proto = ARC_P_ATALK;
 407                 break;
 408         default:
 409                 arc_printk(D_NORMAL, dev, "RFC1201: I don't understand protocol %d (%Xh)\n",
 410                            type, type);
 411                 dev->stats.tx_errors++;
 412                 dev->stats.tx_aborted_errors++;
 413                 return 0;
 414         }
 415
 416         /* Set the source hardware address.
 417          *
 418          * This is pretty pointless for most purposes, but it can help in
 419          * debugging.  ARCnet does not allow us to change the source address
 420          * in the actual packet sent.
 421          */
 422         pkt->hard.source = *dev->dev_addr;
 423
 424         soft->sequence = htons(lp->rfc1201.sequence++);
 425         soft->split_flag = 0;   /* split packets are done elsewhere */
 426
 427         /* see linux/net/ethernet/eth.c to see where I got the following */
 428
 429         if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
 430                 /* FIXME: fill in the last byte of the dest ipaddr here
 431                  * to better comply with RFC1051 in "noarp" mode.
 432                  * For now, always broadcasting will probably at least get
 433                  * packets sent out :)
 434                  */
 435                 pkt->hard.dest = 0;
 436                 return hdr_size;
 437         }
 438         /* otherwise, drop in the dest address */
 439         pkt->hard.dest = daddr;
 440         return hdr_size;
 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 = netdev_priv(dev);
 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 = htons(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
 470         lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE);
 471         lp->hw.copy_to_card(dev, bufnum, ofs, soft, softlen);
 472
 473         lp->lastload_dest = hard->dest;
 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 = netdev_priv(dev);
 480         const int maxsegsize = XMTU - RFC1201_HDR_SIZE;
 481         struct Outgoing *out;
 482
 483         arc_printk(D_DURING, dev, "prepare_tx: txbufs=%d/%d/%d\n",
 484                    lp->next_tx, lp->cur_tx, bufnum);
 485
 486         /* hard header is not included in packet length */
 487         length -= ARC_HDR_SIZE;
 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                 arc_printk(D_DURING, dev, "rfc1201 prep_tx: ready for %d-segment split (%d bytes, seq=%d)\n",
 500                            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 static int continue_tx(struct net_device *dev, int bufnum)
 512 {
 513         struct arcnet_local *lp = netdev_priv(dev);
 514         struct Outgoing *out = &lp->outgoing;
 515         struct arc_hardware *hard = &out->pkt->hard;
 516         struct arc_rfc1201 *soft = &out->pkt->soft.rfc1201, *newsoft;
 517         int maxsegsize = XMTU - RFC1201_HDR_SIZE;
 518         int seglen;
 519
 520         arc_printk(D_DURING, dev,
 521                    "rfc1201 continue_tx: loading segment %d(+1) of %d (seq=%d)\n",
 522                    out->segnum, out->numsegs, soft->sequence);
 523
 524         /* the "new" soft header comes right before the data chunk */
 525         newsoft = (struct arc_rfc1201 *)
 526             (out->pkt->soft.raw + out->length - out->dataleft);
 527
 528         if (!out->segnum)       /* first packet; newsoft == soft */
 529                 newsoft->split_flag = ((out->numsegs - 2) << 1) | 1;
 530         else {
 531                 newsoft->split_flag = out->segnum << 1;
 532                 newsoft->proto = soft->proto;
 533                 newsoft->sequence = soft->sequence;
 534         }
 535
 536         seglen = maxsegsize;
 537         if (seglen > out->dataleft)
 538                 seglen = out->dataleft;
 539         out->dataleft -= seglen;
 540
 541         load_pkt(dev, hard, newsoft, seglen + RFC1201_HDR_SIZE, bufnum);
 542
 543         out->segnum++;
 544         if (out->segnum >= out->numsegs)
 545                 return 1;
 546         else
 547                 return 0;
 548 }