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 } 549