aboutsummaryrefslogtreecommitdiffstats
path: root/net/802/tr.c
blob: 85293ccf7efcd3c66724dd8bfed62d9a1afef19c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
/*
 * NET3:	Token ring device handling subroutines
 * 
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 *
 * Fixes:       3 Feb 97 Paul Norton <pnorton@cts.com> Minor routing fixes.
 *              Added rif table to /proc/net/tr_rif and rif timeout to
 *              /proc/sys/net/token-ring/rif_timeout.
 *              22 Jun 98 Paul Norton <p.norton@computer.org> Rearranged
 *              tr_header and tr_type_trans to handle passing IPX SNAP and
 *              802.2 through the correct layers. Eliminated tr_reformat.
 *        
 */

#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/config.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/jiffies.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/trdevice.h>
#include <linux/skbuff.h>
#include <linux/errno.h>
#include <linux/timer.h>
#include <linux/net.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/init.h>
#include <net/arp.h>

static void tr_add_rif_info(struct trh_hdr *trh, struct net_device *dev);
static void rif_check_expire(unsigned long dummy);

#define TR_SR_DEBUG 0

/*
 *	Each RIF entry we learn is kept this way
 */
 
struct rif_cache_s {	
	unsigned char addr[TR_ALEN];
	int iface;
	__u16 rcf;
	__u16 rseg[8];
	struct rif_cache_s *next;
	unsigned long last_used;
	unsigned char local_ring;
};

#define RIF_TABLE_SIZE 32

/*
 *	We hash the RIF cache 32 ways. We do after all have to look it
 *	up a lot.
 */
 
static struct rif_cache_s *rif_table[RIF_TABLE_SIZE];

static DEFINE_SPINLOCK(rif_lock);


/*
 *	Garbage disposal timer.
 */
 
static struct timer_list rif_timer;

int sysctl_tr_rif_timeout = 60*10*HZ;

static inline unsigned long rif_hash(const unsigned char *addr)
{
	unsigned long x;

	x = addr[0];
	x = (x << 2) ^ addr[1];
	x = (x << 2) ^ addr[2];
	x = (x << 2) ^ addr[3];
	x = (x << 2) ^ addr[4];
	x = (x << 2) ^ addr[5];

	x ^= x >> 8;

	return x & (RIF_TABLE_SIZE - 1);
}

/*
 *	Put the headers on a token ring packet. Token ring source routing
 *	makes this a little more exciting than on ethernet.
 */
 
static int tr_header(struct sk_buff *skb, struct net_device *dev,
		     unsigned short type,
		     void *daddr, void *saddr, unsigned len) 
{
	struct trh_hdr *trh;
	int hdr_len;

	/* 
	 * Add the 802.2 SNAP header if IP as the IPv4/IPv6 code calls  
	 * dev->hard_header directly.
	 */
	if (type == ETH_P_IP || type == ETH_P_IPV6 || type == ETH_P_ARP)
	{
		struct trllc *trllc;

		hdr_len = sizeof(struct trh_hdr) + sizeof(struct trllc);
		trh = (struct trh_hdr *)skb_push(skb, hdr_len);
		trllc = (struct trllc *)(trh+1);
		trllc->dsap = trllc->ssap = EXTENDED_SAP;
		trllc->llc = UI_CMD;
		trllc->protid[0] = trllc->protid[1] = trllc->protid[2] = 0x00;
		trllc->ethertype = htons(type);
	}
	else
	{
		hdr_len = sizeof(struct trh_hdr);
		trh = (struct trh_hdr *)skb_push(skb, hdr_len);	
	}

	trh->ac=AC;
	trh->fc=LLC_FRAME;

	if(saddr)
		memcpy(trh->saddr,saddr,dev->addr_len);
	else
		memcpy(trh->saddr,dev->dev_addr,dev->addr_len);

	/*
	 *	Build the destination and then source route the frame
	 */
	 
	if(daddr) 
	{
		memcpy(trh->daddr,daddr,dev->addr_len);
		tr_source_route(skb,trh,dev);
		return(hdr_len);
	}

	return -hdr_len;
}
	
/*
 *	A neighbour discovery of some species (eg arp) has completed. We
 *	can now send the packet.
 */
 
static int tr_rebuild_header(struct sk_buff *skb) 
{
	struct trh_hdr *trh=(struct trh_hdr *)skb->data;
	struct trllc *trllc=(struct trllc *)(skb->data+sizeof(struct trh_hdr));
	struct net_device *dev = skb->dev;

	/*
	 *	FIXME: We don't yet support IPv6 over token rings
	 */
	 
	if(trllc->ethertype != htons(ETH_P_IP)) {
		printk("tr_rebuild_header: Don't know how to resolve type %04X addresses ?\n",(unsigned int)htons(trllc->ethertype));
		return 0;
	}

#ifdef CONFIG_INET
	if(arp_find(trh->daddr, skb)) {
			return 1;
	}
	else 
#endif	
	{	
		tr_source_route(skb,trh,dev); 
		return 0;
	}
}
	
/*
 *	Some of this is a bit hackish. We intercept RIF information
 *	used for source routing. We also grab IP directly and don't feed
 *	it via SNAP.
 */
 
unsigned short tr_type_trans(struct sk_buff *skb, struct net_device *dev) 
{

	struct trh_hdr *trh=(struct trh_hdr *)skb->data;
	struct trllc *trllc;
	unsigned riflen=0;
	
	skb->mac.raw = skb->data;
	
       	if(trh->saddr[0] & TR_RII)
		riflen = (ntohs(trh->rcf) & TR_RCF_LEN_MASK) >> 8;

	trllc = (struct trllc *)(skb->data+sizeof(struct trh_hdr)-TR_MAXRIFLEN+riflen);

	skb_pull(skb,sizeof(struct trh_hdr)-TR_MAXRIFLEN+riflen);

	if(*trh->daddr & 0x80) 
	{
		if(!memcmp(trh->daddr,dev->broadcast,TR_ALEN)) 	
			skb->pkt_type=PACKET_BROADCAST;
		else
			skb->pkt_type=PACKET_MULTICAST;
	}
	else if ( (trh->daddr[0] & 0x01) && (trh->daddr[1] & 0x00) && (trh->daddr[2] & 0x5E))
	{
		skb->pkt_type=PACKET_MULTICAST;
	}
	else if(dev->flags & IFF_PROMISC) 
	{
		if(memcmp(trh->daddr, dev->dev_addr, TR_ALEN))
			skb->pkt_type=PACKET_OTHERHOST;
	}

	if ((skb->pkt_type != PACKET_BROADCAST) &&
	    (skb->pkt_type != PACKET_MULTICAST))
		tr_add_rif_info(trh,dev) ; 

	/*
	 * Strip the SNAP header from ARP packets since we don't 
	 * pass them through to the 802.2/SNAP layers.
	 */

	if (trllc->dsap == EXTENDED_SAP &&
	    (trllc->ethertype == ntohs(ETH_P_IP) ||
	     trllc->ethertype == ntohs(ETH_P_IPV6) ||
	     trllc->ethertype == ntohs(ETH_P_ARP)))
	{
		skb_pull(skb, sizeof(struct trllc));
		return trllc->ethertype;
	}

	return ntohs(ETH_P_802_2);
}

/*
 *	We try to do source routing... 
 */

void tr_source_route(struct sk_buff *skb,struct trh_hdr *trh,struct net_device *dev) 
{
	int slack;
	unsigned int hash;
	struct rif_cache_s *entry;
	unsigned char *olddata;
	static const unsigned char mcast_func_addr[] 
		= {0xC0,0x00,0x00,0x04,0x00,0x00};
	
	spin_lock_bh(&rif_lock);

	/*
	 *	Broadcasts are single route as stated in RFC 1042 
	 */
	if( (!memcmp(&(trh->daddr[0]),&(dev->broadcast[0]),TR_ALEN)) ||
	    (!memcmp(&(trh->daddr[0]),&(mcast_func_addr[0]), TR_ALEN))  )
	{
		trh->rcf=htons((((sizeof(trh->rcf)) << 8) & TR_RCF_LEN_MASK)  
			       | TR_RCF_FRAME2K | TR_RCF_LIMITED_BROADCAST);
		trh->saddr[0]|=TR_RII;
	}
	else 
	{
		hash = rif_hash(trh->daddr);
		/*
		 *	Walk the hash table and look for an entry
		 */
		for(entry=rif_table[hash];entry && memcmp(&(entry->addr[0]),&(trh->daddr[0]),TR_ALEN);entry=entry->next);

		/*
		 *	If we found an entry we can route the frame.
		 */
		if(entry) 
		{
#if TR_SR_DEBUG
printk("source routing for %02X:%02X:%02X:%02X:%02X:%02X\n",trh->daddr[0],
		  trh->daddr[1],trh->daddr[2],trh->daddr[3],trh->daddr[4],trh->daddr[5]);
#endif
			if(!entry->local_ring && (ntohs(entry->rcf) & TR_RCF_LEN_MASK) >> 8)
			{
				trh->rcf=entry->rcf;
				memcpy(&trh->rseg[0],&entry->rseg[0],8*sizeof(unsigned short));
				trh->rcf^=htons(TR_RCF_DIR_BIT);	
				trh->rcf&=htons(0x1fff);	/* Issam Chehab <ichehab@madge1.demon.co.uk> */

				trh->saddr[0]|=TR_RII;
#if TR_SR_DEBUG
				printk("entry found with rcf %04x\n", entry->rcf);
			}
			else
			{
				printk("entry found but without rcf length, local=%02x\n", entry->local_ring);
#endif
			}
			entry->last_used=jiffies;
		}
		else 
		{
			/*
			 *	Without the information we simply have to shout
			 *	on the wire. The replies should rapidly clean this
			 *	situation up.
			 */
			trh->rcf=htons((((sizeof(trh->rcf)) << 8) & TR_RCF_LEN_MASK)  
				       | TR_RCF_FRAME2K | TR_RCF_LIMITED_BROADCAST);
			trh->saddr[0]|=TR_RII;
#if TR_SR_DEBUG
			printk("no entry in rif table found - broadcasting frame\n");
#endif
		}
	}

	/* Compress the RIF here so we don't have to do it in the driver(s) */
	if (!(trh->saddr[0] & 0x80))
		slack = 18;
	else 
		slack = 18 - ((ntohs(trh->rcf) & TR_RCF_LEN_MASK)>>8);
	olddata = skb->data;
	spin_unlock_bh(&rif_lock);

	skb_pull(skb, slack);
	memmove(skb->data, olddata, sizeof(struct trh_hdr) - slack);
}

/*
 *	We have learned some new RIF information for our source
 *	routing.
 */
 
static void tr_add_rif_info(struct trh_hdr *trh, struct net_device *dev)
{
	unsigned int hash, rii_p = 0;
	struct rif_cache_s *entry;


	spin_lock_bh(&rif_lock);
	
	/*
	 *	Firstly see if the entry exists
	 */

       	if(trh->saddr[0] & TR_RII)
	{
		trh->saddr[0]&=0x7f;
		if (((ntohs(trh->rcf) & TR_RCF_LEN_MASK) >> 8) > 2)
		{
			rii_p = 1;
	        }
	}

	hash = rif_hash(trh->saddr);
	for(entry=rif_table[hash];entry && memcmp(&(entry->addr[0]),&(trh->saddr[0]),TR_ALEN);entry=entry->next);

	if(entry==NULL) 
	{
#if TR_SR_DEBUG
printk("adding rif_entry: addr:%02X:%02X:%02X:%02X:%02X:%02X rcf:%04X\n",
		trh->saddr[0],trh->saddr[1],trh->saddr[2],
       		trh->saddr[3],trh->saddr[4],trh->saddr[5],
		ntohs(trh->rcf));
#endif
		/*
		 *	Allocate our new entry. A failure to allocate loses
		 *	use the information. This is harmless.
		 *
		 *	FIXME: We ought to keep some kind of cache size
		 *	limiting and adjust the timers to suit.
		 */
		entry=kmalloc(sizeof(struct rif_cache_s),GFP_ATOMIC);

		if(!entry) 
		{
			printk(KERN_DEBUG "tr.c: Couldn't malloc rif cache entry !\n");
			spin_unlock_bh(&rif_lock);
			return;
		}

		memcpy(&(entry->addr[0]),&(trh->saddr[0]),TR_ALEN);
		entry->iface = dev->ifindex;
		entry->next=rif_table[hash];
		entry->last_used=jiffies;
		rif_table[hash]=entry;

		if (rii_p)
		{
			entry->rcf = trh->rcf & htons((unsigned short)~TR_RCF_BROADCAST_MASK);
			memcpy(&(entry->rseg[0]),&(trh->rseg[0]),8*sizeof(unsigned short));
			entry->local_ring = 0;
			trh->saddr[0]|=TR_RII; /* put the routing indicator back for tcpdump */
		}
		else
		{
			entry->local_ring = 1;
		}
	} 	
	else	/* Y. Tahara added */
	{ 
		/*
		 *	Update existing entries
		 */
		if (!entry->local_ring) 
		    if (entry->rcf != (trh->rcf & htons((unsigned short)~TR_RCF_BROADCAST_MASK)) &&
			 !(trh->rcf & htons(TR_RCF_BROADCAST_MASK)))
		    {
#if TR_SR_DEBUG
printk("updating rif_entry: addr:%02X:%02X:%02X:%02X:%02X:%02X rcf:%04X\n",
		trh->saddr[0],trh->saddr[1],trh->saddr[2],
		trh->saddr[3],trh->saddr[4],trh->saddr[5],
		ntohs(trh->rcf));
#endif
			    entry->rcf = trh->rcf & htons((unsigned short)~TR_RCF_BROADCAST_MASK);
        		    memcpy(&(entry->rseg[0]),&(trh->rseg[0]),8*sizeof(unsigned short));
		    }                                         
           	entry->last_used=jiffies;               
	}
	spin_unlock_bh(&rif_lock);
}

/*
 *	Scan the cache with a timer and see what we need to throw out.
 */

static void rif_check_expire(unsigned long dummy) 
{
	int i;
	unsigned long next_interval = jiffies + sysctl_tr_rif_timeout/2;

	spin_lock_bh(&rif_lock);
	
	for(i =0; i < RIF_TABLE_SIZE; i++) {
		struct rif_cache_s *entry, **pentry;
		
		pentry = rif_table+i;
		while((entry=*pentry) != NULL) {
			unsigned long expires
				= entry->last_used + sysctl_tr_rif_timeout;

			if (time_before_eq(expires, jiffies)) {
				*pentry = entry->next;
				kfree(entry);
			} else {
				pentry = &entry->next;

				if (time_before(expires, next_interval))
					next_interval = expires;
			}
		}
	}
	
	spin_unlock_bh(&rif_lock);

	mod_timer(&rif_timer, next_interval);

}

/*
 *	Generate the /proc/net information for the token ring RIF
 *	routing.
 */
 
#ifdef CONFIG_PROC_FS

static struct rif_cache_s *rif_get_idx(loff_t pos)
{
	int i;
	struct rif_cache_s *entry;
	loff_t off = 0;

	for(i = 0; i < RIF_TABLE_SIZE; i++) 
		for(entry = rif_table[i]; entry; entry = entry->next) {
			if (off == pos)
				return entry;
			++off;
		}

	return NULL;
}

static void *rif_seq_start(struct seq_file *seq, loff_t *pos)
{
	spin_lock_bh(&rif_lock);

	return *pos ? rif_get_idx(*pos - 1) : SEQ_START_TOKEN;
}

static void *rif_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	int i;
	struct rif_cache_s *ent = v;

	++*pos;

	if (v == SEQ_START_TOKEN) {
		i = -1;
		goto scan;
	}

	if (ent->next) 
		return ent->next;

	i = rif_hash(ent->addr);
 scan:
	while (++i < RIF_TABLE_SIZE) {
		if ((ent = rif_table[i]) != NULL)
			return ent;
	}
	return NULL;
}

static void rif_seq_stop(struct seq_file *seq, void *v)
{
	spin_unlock_bh(&rif_lock);
}

static int rif_seq_show(struct seq_file *seq, void *v)
{
	int j, rcf_len, segment, brdgnmb;
	struct rif_cache_s *entry = v;

	if (v == SEQ_START_TOKEN)
		seq_puts(seq,
		     "if     TR address       TTL   rcf   routing segments\n");
	else {
		struct net_device *dev = dev_get_by_index(entry->iface);
		long ttl = (long) (entry->last_used + sysctl_tr_rif_timeout)
				- (long) jiffies;

		seq_printf(seq, "%s %02X:%02X:%02X:%02X:%02X:%02X %7li ",
			   dev?dev->name:"?",
			   entry->addr[0],entry->addr[1],entry->addr[2],
			   entry->addr[3],entry->addr[4],entry->addr[5],
			   ttl/HZ);

			if (entry->local_ring)
			        seq_puts(seq, "local\n");
			else {

				seq_printf(seq, "%04X", ntohs(entry->rcf));
				rcf_len = ((ntohs(entry->rcf) & TR_RCF_LEN_MASK)>>8)-2; 
				if (rcf_len)
				        rcf_len >>= 1;
				for(j = 1; j < rcf_len; j++) {
					if(j==1) {
						segment=ntohs(entry->rseg[j-1])>>4;
						seq_printf(seq,"  %03X",segment);
					};
					segment=ntohs(entry->rseg[j])>>4;
					brdgnmb=ntohs(entry->rseg[j-1])&0x00f;
					seq_printf(seq,"-%01X-%03X",brdgnmb,segment);
				}
				seq_putc(seq, '\n');
			}
	   	}
	return 0;
}


static struct seq_operations rif_seq_ops = {
	.start = rif_seq_start,
	.next  = rif_seq_next,
	.stop  = rif_seq_stop,
	.show  = rif_seq_show,
};

static int rif_seq_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &rif_seq_ops);
}

static struct file_operations rif_seq_fops = {
	.owner	 = THIS_MODULE,
	.open    = rif_seq_open,
	.read    = seq_read,
	.llseek  = seq_lseek,
	.release = seq_release,
};

#endif

static void tr_setup(struct net_device *dev)
{
	/*
	 *	Configure and register
	 */
	
	dev->hard_header	= tr_header;
	dev->rebuild_header	= tr_rebuild_header;

	dev->type		= ARPHRD_IEEE802_TR;
	dev->hard_header_len	= TR_HLEN;
	dev->mtu		= 2000;
	dev->addr_len		= TR_ALEN;
	dev->tx_queue_len	= 100;	/* Long queues on tr */
	
	memset(dev->broadcast,0xFF, TR_ALEN);

	/* New-style flags. */
	dev->flags		= IFF_BROADCAST | IFF_MULTICAST ;
}

/**
 * alloc_trdev - Register token ring device
 * @sizeof_priv: Size of additional driver-private structure to be allocated
 *	for this token ring device
 *
 * Fill in the fields of the device structure with token ring-generic values.
 *
 * Constructs a new net device, complete with a private data area of
 * size @sizeof_priv.  A 32-byte (not bit) alignment is enforced for
 * this private data area.
 */
struct net_device *alloc_trdev(int sizeof_priv)
{
	return alloc_netdev(sizeof_priv, "tr%d", tr_setup);
}

/*
 *	Called during bootup.  We don't actually have to initialise
 *	too much for this.
 */

static int __init rif_init(void)
{
	init_timer(&rif_timer);
	rif_timer.expires  = sysctl_tr_rif_timeout;
	rif_timer.data     = 0L;
	rif_timer.function = rif_check_expire;
	add_timer(&rif_timer);

	proc_net_fops_create("tr_rif", S_IRUGO, &rif_seq_fops);
	return 0;
}

module_init(rif_init);

EXPORT_SYMBOL(tr_source_route);
EXPORT_SYMBOL(tr_type_trans);
EXPORT_SYMBOL(alloc_trdev);