962641e9645006ca53e4c3611d3b4825163971b6
[linux-2.6.git] / 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 #include <linux/module.h>
27 #include <linux/init.h>
28 #include <linux/if_arp.h>
29 #include <linux/netdevice.h>
30 #include <linux/skbuff.h>
31 #include <linux/arcdevice.h>
32
33 MODULE_LICENSE("GPL");
34 #define VERSION "arcnet: RFC1201 \"standard\" (`a') encapsulation support loaded.\n"
35
36
37 static __be16 type_trans(struct sk_buff *skb, struct net_device *dev);
38 static void rx(struct net_device *dev, int bufnum,
39                struct archdr *pkthdr, int length);
40 static int build_header(struct sk_buff *skb, struct net_device *dev,
41                         unsigned short type, uint8_t daddr);
42 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
43                       int bufnum);
44 static int continue_tx(struct net_device *dev, int bufnum);
45
46 static struct ArcProto rfc1201_proto =
47 {
48         .suffix         = 'a',
49         .mtu            = 1500, /* could be more, but some receivers can't handle it... */
50         .is_ip          = 1,    /* This is for sending IP and ARP packages */
51         .rx             = rx,
52         .build_header   = build_header,
53         .prepare_tx     = prepare_tx,
54         .continue_tx    = continue_tx,
55         .ack_tx         = NULL
56 };
57
58
59 static int __init arcnet_rfc1201_init(void)
60 {
61         printk(VERSION);
62
63         arc_proto_map[ARC_P_IP]
64             = arc_proto_map[ARC_P_IPV6]
65             = arc_proto_map[ARC_P_ARP]
66             = arc_proto_map[ARC_P_RARP]
67             = arc_proto_map[ARC_P_IPX]
68             = arc_proto_map[ARC_P_NOVELL_EC]
69             = &rfc1201_proto;
70
71         /* if someone else already owns the broadcast, we won't take it */
72         if (arc_bcast_proto == arc_proto_default)
73                 arc_bcast_proto = &rfc1201_proto;
74
75         return 0;
76 }
77
78 static void __exit arcnet_rfc1201_exit(void)
79 {
80         arcnet_unregister_proto(&rfc1201_proto);
81 }
82
83 module_init(arcnet_rfc1201_init);
84 module_exit(arcnet_rfc1201_exit);
85
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         struct arcnet_local *lp = dev->priv;
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                 lp->stats.rx_errors++;
125                 lp->stats.rx_crc_errors++;
126                 return 0;
127         }
128
129         return htons(ETH_P_IP);
130 }
131
132
133 /* packet receiver */
134 static void rx(struct net_device *dev, int bufnum,
135                struct archdr *pkthdr, int length)
136 {
137         struct arcnet_local *lp = dev->priv;
138         struct sk_buff *skb;
139         struct archdr *pkt = pkthdr;
140         struct arc_rfc1201 *soft = &pkthdr->soft.rfc1201;
141         int saddr = pkt->hard.source, ofs;
142         struct Incoming *in = &lp->rfc1201.incoming[saddr];
143
144         BUGMSG(D_DURING, "it's an RFC1201 packet (length=%d)\n", 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                         BUGMSG(D_DURING, "compensating for exception packet\n");
154                 else {
155                         BUGMSG(D_EXTRA, "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                 BUGMSG(D_RX, "incoming is not split (splitflag=%d)\n",
168                        soft->split_flag);
169
170                 if (in->skb) {  /* already assembling one! */
171                         BUGMSG(D_EXTRA, "aborting assembly (seq=%d) for unsplit packet (splitflag=%d, seq=%d)\n",
172                          in->sequence, soft->split_flag, soft->sequence);
173                         lp->rfc1201.aborted_seq = soft->sequence;
174                         dev_kfree_skb_irq(in->skb);
175                         lp->stats.rx_errors++;
176                         lp->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 == NULL) {
183                         BUGMSG(D_NORMAL, "Memory squeeze, dropping packet.\n");
184                         lp->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 been copied from the card */
194                 memcpy(pkt, pkthdr, sizeof(struct archdr));
195                 if (length > sizeof(pkt->soft))
196                         lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft),
197                                        pkt->soft.raw + sizeof(pkt->soft),
198                                               length - sizeof(pkt->soft));
199
200                 /*
201                  * ARP packets have problems when sent from some DOS systems: the
202                  * source address is always 0!  So we take the hardware source addr
203                  * (which is impossible to fumble) and insert it ourselves.
204                  */
205                 if (soft->proto == ARC_P_ARP) {
206                         struct arphdr *arp = (struct arphdr *) soft->payload;
207
208                         /* make sure addresses are the right length */
209                         if (arp->ar_hln == 1 && arp->ar_pln == 4) {
210                                 uint8_t *cptr = (uint8_t *) arp + sizeof(struct arphdr);
211
212                                 if (!*cptr) {   /* is saddr = 00? */
213                                         BUGMSG(D_EXTRA,
214                                                "ARP source address was 00h, set to %02Xh.\n",
215                                                saddr);
216                                         lp->stats.rx_crc_errors++;
217                                         *cptr = saddr;
218                                 } else {
219                                         BUGMSG(D_DURING, "ARP source address (%Xh) is fine.\n",
220                                                *cptr);
221                                 }
222                         } else {
223                                 BUGMSG(D_NORMAL, "funny-shaped ARP packet. (%Xh, %Xh)\n",
224                                        arp->ar_hln, arp->ar_pln);
225                                 lp->stats.rx_errors++;
226                                 lp->stats.rx_crc_errors++;
227                         }
228                 }
229                 BUGLVL(D_SKB) arcnet_dump_skb(dev, skb, "rx");
230
231                 skb->protocol = type_trans(skb, dev);
232                 netif_rx(skb);
233         } else {                /* split packet */
234                 /*
235                  * NOTE: MSDOS ARP packet correction should only need to apply to
236                  * unsplit packets, since ARP packets are so short.
237                  *
238                  * My interpretation of the RFC1201 document is that if a packet is
239                  * received out of order, the entire assembly process should be
240                  * aborted.
241                  *
242                  * The RFC also mentions "it is possible for successfully received
243                  * packets to be retransmitted." As of 0.40 all previously received
244                  * packets are allowed, not just the most recent one.
245                  *
246                  * We allow multiple assembly processes, one for each ARCnet card
247                  * possible on the network.  Seems rather like a waste of memory,
248                  * but there's no other way to be reliable.
249                  */
250
251                 BUGMSG(D_RX, "packet is split (splitflag=%d, seq=%d)\n",
252                        soft->split_flag, in->sequence);
253
254                 if (in->skb && in->sequence != soft->sequence) {
255                         BUGMSG(D_EXTRA, "wrong seq number (saddr=%d, expected=%d, seq=%d, splitflag=%d)\n",
256                                saddr, in->sequence, soft->sequence,
257                                soft->split_flag);
258                         dev_kfree_skb_irq(in->skb);
259                         in->skb = NULL;
260                         lp->stats.rx_errors++;
261                         lp->stats.rx_missed_errors++;
262                         in->lastpacket = in->numpackets = 0;
263                 }
264                 if (soft->split_flag & 1) {     /* first packet in split */
265                         BUGMSG(D_RX, "brand new splitpacket (splitflag=%d)\n",
266                                soft->split_flag);
267                         if (in->skb) {  /* already assembling one! */
268                                 BUGMSG(D_EXTRA, "aborting previous (seq=%d) assembly "
269                                        "(splitflag=%d, seq=%d)\n",
270                                        in->sequence, soft->split_flag,
271                                        soft->sequence);
272                                 lp->stats.rx_errors++;
273                                 lp->stats.rx_missed_errors++;
274                                 dev_kfree_skb_irq(in->skb);
275                         }
276                         in->sequence = soft->sequence;
277                         in->numpackets = ((unsigned) soft->split_flag >> 1) + 2;
278                         in->lastpacket = 1;
279
280                         if (in->numpackets > 16) {
281                                 BUGMSG(D_EXTRA, "incoming packet more than 16 segments; dropping. (splitflag=%d)\n",
282                                        soft->split_flag);
283                                 lp->rfc1201.aborted_seq = soft->sequence;
284                                 lp->stats.rx_errors++;
285                                 lp->stats.rx_length_errors++;
286                                 return;
287                         }
288                         in->skb = skb = alloc_skb(508 * in->numpackets + ARC_HDR_SIZE,
289                                                   GFP_ATOMIC);
290                         if (skb == NULL) {
291                                 BUGMSG(D_NORMAL, "(split) memory squeeze, dropping packet.\n");
292                                 lp->rfc1201.aborted_seq = soft->sequence;
293                                 lp->stats.rx_dropped++;
294                                 return;
295                         }
296                         skb->dev = dev;
297                         pkt = (struct archdr *) skb->data;
298                         soft = &pkt->soft.rfc1201;
299
300                         memcpy(pkt, pkthdr, ARC_HDR_SIZE + RFC1201_HDR_SIZE);
301                         skb_put(skb, ARC_HDR_SIZE + RFC1201_HDR_SIZE);
302
303                         soft->split_flag = 0;   /* end result won't be split */
304                 } else {        /* not first packet */
305                         int packetnum = ((unsigned) soft->split_flag >> 1) + 1;
306
307                         /*
308                          * if we're not assembling, there's no point trying to
309                          * continue.
310                          */
311                         if (!in->skb) {
312                                 if (lp->rfc1201.aborted_seq != soft->sequence) {
313                                         BUGMSG(D_EXTRA, "can't continue split without starting "
314                                                "first! (splitflag=%d, seq=%d, aborted=%d)\n",
315                                         soft->split_flag, soft->sequence,
316                                                lp->rfc1201.aborted_seq);
317                                         lp->stats.rx_errors++;
318                                         lp->stats.rx_missed_errors++;
319                                 }
320                                 return;
321                         }
322                         in->lastpacket++;
323                         if (packetnum != in->lastpacket) {      /* not the right flag! */
324                                 /* harmless duplicate? ignore. */
325                                 if (packetnum <= in->lastpacket - 1) {
326                                         BUGMSG(D_EXTRA, "duplicate splitpacket ignored! (splitflag=%d)\n",
327                                                soft->split_flag);
328                                         lp->stats.rx_errors++;
329                                         lp->stats.rx_frame_errors++;
330                                         return;
331                                 }
332                                 /* "bad" duplicate, kill reassembly */
333                                 BUGMSG(D_EXTRA, "out-of-order splitpacket, reassembly "
334                                        "(seq=%d) aborted (splitflag=%d, seq=%d)\n",
335                                        in->sequence, soft->split_flag, soft->sequence);
336                                 lp->rfc1201.aborted_seq = soft->sequence;
337                                 dev_kfree_skb_irq(in->skb);
338                                 in->skb = NULL;
339                                 lp->stats.rx_errors++;
340                                 lp->stats.rx_missed_errors++;
341                                 in->lastpacket = in->numpackets = 0;
342                                 return;
343                         }
344                         pkt = (struct archdr *) in->skb->data;
345                         soft = &pkt->soft.rfc1201;
346                 }
347
348                 skb = in->skb;
349
350                 lp->hw.copy_from_card(dev, bufnum, ofs + RFC1201_HDR_SIZE,
351                                       skb->data + skb->len,
352                                       length - RFC1201_HDR_SIZE);
353                 skb_put(skb, length - RFC1201_HDR_SIZE);
354
355                 /* are we done? */
356                 if (in->lastpacket == in->numpackets) {
357                         in->skb = NULL;
358                         in->lastpacket = in->numpackets = 0;
359
360             BUGMSG(D_SKB_SIZE, "skb: received %d bytes from %02X (unsplit)\n",
361                 skb->len, pkt->hard.source);
362             BUGMSG(D_SKB_SIZE, "skb: received %d bytes from %02X (split)\n",
363                 skb->len, pkt->hard.source);
364                         BUGLVL(D_SKB) arcnet_dump_skb(dev, skb, "rx");
365
366                         skb->protocol = type_trans(skb, dev);
367                         netif_rx(skb);
368                 }
369         }
370 }
371
372
373 /* Create the ARCnet hard/soft headers for RFC1201. */
374 static int build_header(struct sk_buff *skb, struct net_device *dev,
375                         unsigned short type, uint8_t daddr)
376 {
377         struct arcnet_local *lp = dev->priv;
378         int hdr_size = ARC_HDR_SIZE + RFC1201_HDR_SIZE;
379         struct archdr *pkt = (struct archdr *) skb_push(skb, hdr_size);
380         struct arc_rfc1201 *soft = &pkt->soft.rfc1201;
381
382         /* set the protocol ID according to RFC1201 */
383         switch (type) {
384         case ETH_P_IP:
385                 soft->proto = ARC_P_IP;
386                 break;
387         case ETH_P_IPV6:
388                 soft->proto = ARC_P_IPV6;
389                 break;
390         case ETH_P_ARP:
391                 soft->proto = ARC_P_ARP;
392                 break;
393         case ETH_P_RARP:
394                 soft->proto = ARC_P_RARP;
395                 break;
396         case ETH_P_IPX:
397         case ETH_P_802_3:
398         case ETH_P_802_2:
399                 soft->proto = ARC_P_IPX;
400                 break;
401         case ETH_P_ATALK:
402                 soft->proto = ARC_P_ATALK;
403                 break;
404         default:
405                 BUGMSG(D_NORMAL, "RFC1201: I don't understand protocol %d (%Xh)\n",
406                        type, type);
407                 lp->stats.tx_errors++;
408                 lp->stats.tx_aborted_errors++;
409                 return 0;
410         }
411
412         /*
413          * Set the source hardware address.
414          *
415          * This is pretty pointless for most purposes, but it can help in
416          * debugging.  ARCnet does not allow us to change the source address in
417          * the actual packet sent)
418          */
419         pkt->hard.source = *dev->dev_addr;
420
421         soft->sequence = htons(lp->rfc1201.sequence++);
422         soft->split_flag = 0;   /* split packets are done elsewhere */
423
424         /* see linux/net/ethernet/eth.c to see where I got the following */
425
426         if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
427                 /* 
428                  * FIXME: fill in the last byte of the dest ipaddr here to better
429                  * comply with RFC1051 in "noarp" mode.  For now, always broadcasting
430                  * will probably at least get packets sent out :)
431                  */
432                 pkt->hard.dest = 0;
433                 return hdr_size;
434         }
435         /* otherwise, drop in the dest address */
436         pkt->hard.dest = daddr;
437         return hdr_size;
438 }
439
440
441 static void load_pkt(struct net_device *dev, struct arc_hardware *hard,
442                      struct arc_rfc1201 *soft, int softlen, int bufnum)
443 {
444         struct arcnet_local *lp = dev->priv;
445         int ofs;
446
447         /* assume length <= XMTU: someone should have handled that by now. */
448
449         if (softlen > MinTU) {
450                 hard->offset[0] = 0;
451                 hard->offset[1] = ofs = 512 - softlen;
452         } else if (softlen > MTU) {     /* exception packet - add an extra header */
453                 struct arc_rfc1201 excsoft;
454
455                 excsoft.proto = soft->proto;
456                 excsoft.split_flag = 0xff;
457                 excsoft.sequence = htons(0xffff);
458
459                 hard->offset[0] = 0;
460                 ofs = 512 - softlen;
461                 hard->offset[1] = ofs - RFC1201_HDR_SIZE;
462                 lp->hw.copy_to_card(dev, bufnum, ofs - RFC1201_HDR_SIZE,
463                                     &excsoft, RFC1201_HDR_SIZE);
464         } else
465                 hard->offset[0] = ofs = 256 - softlen;
466
467         lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE);
468         lp->hw.copy_to_card(dev, bufnum, ofs, soft, softlen);
469
470         lp->lastload_dest = hard->dest;
471 }
472
473
474 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
475                       int bufnum)
476 {
477         struct arcnet_local *lp = dev->priv;
478         const int maxsegsize = XMTU - RFC1201_HDR_SIZE;
479         struct Outgoing *out;
480
481
482         BUGMSG(D_DURING, "prepare_tx: txbufs=%d/%d/%d\n",
483                lp->next_tx, lp->cur_tx, bufnum);
484
485         length -= ARC_HDR_SIZE; /* hard header is not included in packet length */
486         pkt->soft.rfc1201.split_flag = 0;
487
488         /* need to do a split packet? */
489         if (length > XMTU) {
490                 out = &lp->outgoing;
491
492                 out->length = length - RFC1201_HDR_SIZE;
493                 out->dataleft = lp->outgoing.length;
494                 out->numsegs = (out->dataleft + maxsegsize - 1) / maxsegsize;
495                 out->segnum = 0;
496
497                 BUGMSG(D_DURING, "rfc1201 prep_tx: ready for %d-segment split "
498                        "(%d bytes, seq=%d)\n", out->numsegs, out->length,
499                        pkt->soft.rfc1201.sequence);
500
501                 return 0;       /* not done */
502         }
503         /* just load the packet into the buffers and send it off */
504         load_pkt(dev, &pkt->hard, &pkt->soft.rfc1201, length, bufnum);
505
506         return 1;               /* done */
507 }
508
509
510 static int continue_tx(struct net_device *dev, int bufnum)
511 {
512         struct arcnet_local *lp = dev->priv;
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         BUGMSG(D_DURING,
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 }