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
arcnet_rfc1201_init(void)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
arcnet_rfc1201_exit(void)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 */
type_trans(struct sk_buff * skb,struct net_device * dev)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 */
rx(struct net_device * dev,int bufnum,struct archdr * pkthdr,int length)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. */
build_header(struct sk_buff * skb,struct net_device * dev,unsigned short type,uint8_t daddr)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 = (struct archdr *)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
load_pkt(struct net_device * dev,struct arc_hardware * hard,struct arc_rfc1201 * soft,int softlen,int bufnum)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
prepare_tx(struct net_device * dev,struct archdr * pkt,int length,int bufnum)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
continue_tx(struct net_device * dev,int bufnum)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