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 } 548