[TR]: endiannness annotations
[linux-2.6.git] / net / 802 / tr.c
1 /*
2  * NET3:        Token ring device handling subroutines
3  * 
4  *              This program is free software; you can redistribute it and/or
5  *              modify it under the terms of the GNU General Public License
6  *              as published by the Free Software Foundation; either version
7  *              2 of the License, or (at your option) any later version.
8  *
9  * Fixes:       3 Feb 97 Paul Norton <pnorton@cts.com> Minor routing fixes.
10  *              Added rif table to /proc/net/tr_rif and rif timeout to
11  *              /proc/sys/net/token-ring/rif_timeout.
12  *              22 Jun 98 Paul Norton <p.norton@computer.org> Rearranged
13  *              tr_header and tr_type_trans to handle passing IPX SNAP and
14  *              802.2 through the correct layers. Eliminated tr_reformat.
15  *        
16  */
17
18 #include <asm/uaccess.h>
19 #include <asm/system.h>
20 #include <linux/module.h>
21 #include <linux/types.h>
22 #include <linux/kernel.h>
23 #include <linux/jiffies.h>
24 #include <linux/string.h>
25 #include <linux/mm.h>
26 #include <linux/socket.h>
27 #include <linux/in.h>
28 #include <linux/inet.h>
29 #include <linux/netdevice.h>
30 #include <linux/trdevice.h>
31 #include <linux/skbuff.h>
32 #include <linux/errno.h>
33 #include <linux/timer.h>
34 #include <linux/net.h>
35 #include <linux/proc_fs.h>
36 #include <linux/seq_file.h>
37 #include <linux/init.h>
38 #include <net/arp.h>
39
40 static void tr_add_rif_info(struct trh_hdr *trh, struct net_device *dev);
41 static void rif_check_expire(unsigned long dummy);
42
43 #define TR_SR_DEBUG 0
44
45 /*
46  *      Each RIF entry we learn is kept this way
47  */
48  
49 struct rif_cache {
50         unsigned char addr[TR_ALEN];
51         int iface;
52         __be16 rcf;
53         __be16 rseg[8];
54         struct rif_cache *next;
55         unsigned long last_used;
56         unsigned char local_ring;
57 };
58
59 #define RIF_TABLE_SIZE 32
60
61 /*
62  *      We hash the RIF cache 32 ways. We do after all have to look it
63  *      up a lot.
64  */
65  
66 static struct rif_cache *rif_table[RIF_TABLE_SIZE];
67
68 static DEFINE_SPINLOCK(rif_lock);
69
70
71 /*
72  *      Garbage disposal timer.
73  */
74  
75 static struct timer_list rif_timer;
76
77 int sysctl_tr_rif_timeout = 60*10*HZ;
78
79 static inline unsigned long rif_hash(const unsigned char *addr)
80 {
81         unsigned long x;
82
83         x = addr[0];
84         x = (x << 2) ^ addr[1];
85         x = (x << 2) ^ addr[2];
86         x = (x << 2) ^ addr[3];
87         x = (x << 2) ^ addr[4];
88         x = (x << 2) ^ addr[5];
89
90         x ^= x >> 8;
91
92         return x & (RIF_TABLE_SIZE - 1);
93 }
94
95 /*
96  *      Put the headers on a token ring packet. Token ring source routing
97  *      makes this a little more exciting than on ethernet.
98  */
99  
100 static int tr_header(struct sk_buff *skb, struct net_device *dev,
101                      unsigned short type,
102                      void *daddr, void *saddr, unsigned len) 
103 {
104         struct trh_hdr *trh;
105         int hdr_len;
106
107         /* 
108          * Add the 802.2 SNAP header if IP as the IPv4/IPv6 code calls  
109          * dev->hard_header directly.
110          */
111         if (type == ETH_P_IP || type == ETH_P_IPV6 || type == ETH_P_ARP)
112         {
113                 struct trllc *trllc;
114
115                 hdr_len = sizeof(struct trh_hdr) + sizeof(struct trllc);
116                 trh = (struct trh_hdr *)skb_push(skb, hdr_len);
117                 trllc = (struct trllc *)(trh+1);
118                 trllc->dsap = trllc->ssap = EXTENDED_SAP;
119                 trllc->llc = UI_CMD;
120                 trllc->protid[0] = trllc->protid[1] = trllc->protid[2] = 0x00;
121                 trllc->ethertype = htons(type);
122         }
123         else
124         {
125                 hdr_len = sizeof(struct trh_hdr);
126                 trh = (struct trh_hdr *)skb_push(skb, hdr_len); 
127         }
128
129         trh->ac=AC;
130         trh->fc=LLC_FRAME;
131
132         if(saddr)
133                 memcpy(trh->saddr,saddr,dev->addr_len);
134         else
135                 memcpy(trh->saddr,dev->dev_addr,dev->addr_len);
136
137         /*
138          *      Build the destination and then source route the frame
139          */
140          
141         if(daddr) 
142         {
143                 memcpy(trh->daddr,daddr,dev->addr_len);
144                 tr_source_route(skb,trh,dev);
145                 return(hdr_len);
146         }
147
148         return -hdr_len;
149 }
150         
151 /*
152  *      A neighbour discovery of some species (eg arp) has completed. We
153  *      can now send the packet.
154  */
155  
156 static int tr_rebuild_header(struct sk_buff *skb) 
157 {
158         struct trh_hdr *trh=(struct trh_hdr *)skb->data;
159         struct trllc *trllc=(struct trllc *)(skb->data+sizeof(struct trh_hdr));
160         struct net_device *dev = skb->dev;
161
162         /*
163          *      FIXME: We don't yet support IPv6 over token rings
164          */
165          
166         if(trllc->ethertype != htons(ETH_P_IP)) {
167                 printk("tr_rebuild_header: Don't know how to resolve type %04X addresses ?\n", ntohs(trllc->ethertype));
168                 return 0;
169         }
170
171 #ifdef CONFIG_INET
172         if(arp_find(trh->daddr, skb)) {
173                         return 1;
174         }
175         else 
176 #endif  
177         {       
178                 tr_source_route(skb,trh,dev); 
179                 return 0;
180         }
181 }
182         
183 /*
184  *      Some of this is a bit hackish. We intercept RIF information
185  *      used for source routing. We also grab IP directly and don't feed
186  *      it via SNAP.
187  */
188  
189 __be16 tr_type_trans(struct sk_buff *skb, struct net_device *dev)
190 {
191
192         struct trh_hdr *trh=(struct trh_hdr *)skb->data;
193         struct trllc *trllc;
194         unsigned riflen=0;
195         
196         skb->mac.raw = skb->data;
197         
198         if(trh->saddr[0] & TR_RII)
199                 riflen = (ntohs(trh->rcf) & TR_RCF_LEN_MASK) >> 8;
200
201         trllc = (struct trllc *)(skb->data+sizeof(struct trh_hdr)-TR_MAXRIFLEN+riflen);
202
203         skb_pull(skb,sizeof(struct trh_hdr)-TR_MAXRIFLEN+riflen);
204
205         if(*trh->daddr & 0x80) 
206         {
207                 if(!memcmp(trh->daddr,dev->broadcast,TR_ALEN))  
208                         skb->pkt_type=PACKET_BROADCAST;
209                 else
210                         skb->pkt_type=PACKET_MULTICAST;
211         }
212         else if ( (trh->daddr[0] & 0x01) && (trh->daddr[1] & 0x00) && (trh->daddr[2] & 0x5E))
213         {
214                 skb->pkt_type=PACKET_MULTICAST;
215         }
216         else if(dev->flags & IFF_PROMISC) 
217         {
218                 if(memcmp(trh->daddr, dev->dev_addr, TR_ALEN))
219                         skb->pkt_type=PACKET_OTHERHOST;
220         }
221
222         if ((skb->pkt_type != PACKET_BROADCAST) &&
223             (skb->pkt_type != PACKET_MULTICAST))
224                 tr_add_rif_info(trh,dev) ; 
225
226         /*
227          * Strip the SNAP header from ARP packets since we don't 
228          * pass them through to the 802.2/SNAP layers.
229          */
230
231         if (trllc->dsap == EXTENDED_SAP &&
232             (trllc->ethertype == htons(ETH_P_IP) ||
233              trllc->ethertype == htons(ETH_P_IPV6) ||
234              trllc->ethertype == htons(ETH_P_ARP)))
235         {
236                 skb_pull(skb, sizeof(struct trllc));
237                 return trllc->ethertype;
238         }
239
240         return htons(ETH_P_TR_802_2);
241 }
242
243 /*
244  *      We try to do source routing... 
245  */
246
247 void tr_source_route(struct sk_buff *skb,struct trh_hdr *trh,struct net_device *dev) 
248 {
249         int slack;
250         unsigned int hash;
251         struct rif_cache *entry;
252         unsigned char *olddata;
253         unsigned long flags;
254         static const unsigned char mcast_func_addr[] 
255                 = {0xC0,0x00,0x00,0x04,0x00,0x00};
256         
257         spin_lock_irqsave(&rif_lock, flags);
258
259         /*
260          *      Broadcasts are single route as stated in RFC 1042 
261          */
262         if( (!memcmp(&(trh->daddr[0]),&(dev->broadcast[0]),TR_ALEN)) ||
263             (!memcmp(&(trh->daddr[0]),&(mcast_func_addr[0]), TR_ALEN))  )
264         {
265                 trh->rcf=htons((((sizeof(trh->rcf)) << 8) & TR_RCF_LEN_MASK)  
266                                | TR_RCF_FRAME2K | TR_RCF_LIMITED_BROADCAST);
267                 trh->saddr[0]|=TR_RII;
268         }
269         else 
270         {
271                 hash = rif_hash(trh->daddr);
272                 /*
273                  *      Walk the hash table and look for an entry
274                  */
275                 for(entry=rif_table[hash];entry && memcmp(&(entry->addr[0]),&(trh->daddr[0]),TR_ALEN);entry=entry->next);
276
277                 /*
278                  *      If we found an entry we can route the frame.
279                  */
280                 if(entry) 
281                 {
282 #if TR_SR_DEBUG
283 printk("source routing for %02X:%02X:%02X:%02X:%02X:%02X\n",trh->daddr[0],
284                   trh->daddr[1],trh->daddr[2],trh->daddr[3],trh->daddr[4],trh->daddr[5]);
285 #endif
286                         if(!entry->local_ring && (ntohs(entry->rcf) & TR_RCF_LEN_MASK) >> 8)
287                         {
288                                 trh->rcf=entry->rcf;
289                                 memcpy(&trh->rseg[0],&entry->rseg[0],8*sizeof(unsigned short));
290                                 trh->rcf^=htons(TR_RCF_DIR_BIT);        
291                                 trh->rcf&=htons(0x1fff);        /* Issam Chehab <ichehab@madge1.demon.co.uk> */
292
293                                 trh->saddr[0]|=TR_RII;
294 #if TR_SR_DEBUG
295                                 printk("entry found with rcf %04x\n", entry->rcf);
296                         }
297                         else
298                         {
299                                 printk("entry found but without rcf length, local=%02x\n", entry->local_ring);
300 #endif
301                         }
302                         entry->last_used=jiffies;
303                 }
304                 else 
305                 {
306                         /*
307                          *      Without the information we simply have to shout
308                          *      on the wire. The replies should rapidly clean this
309                          *      situation up.
310                          */
311                         trh->rcf=htons((((sizeof(trh->rcf)) << 8) & TR_RCF_LEN_MASK)  
312                                        | TR_RCF_FRAME2K | TR_RCF_LIMITED_BROADCAST);
313                         trh->saddr[0]|=TR_RII;
314 #if TR_SR_DEBUG
315                         printk("no entry in rif table found - broadcasting frame\n");
316 #endif
317                 }
318         }
319
320         /* Compress the RIF here so we don't have to do it in the driver(s) */
321         if (!(trh->saddr[0] & 0x80))
322                 slack = 18;
323         else 
324                 slack = 18 - ((ntohs(trh->rcf) & TR_RCF_LEN_MASK)>>8);
325         olddata = skb->data;
326         spin_unlock_irqrestore(&rif_lock, flags);
327
328         skb_pull(skb, slack);
329         memmove(skb->data, olddata, sizeof(struct trh_hdr) - slack);
330 }
331
332 /*
333  *      We have learned some new RIF information for our source
334  *      routing.
335  */
336  
337 static void tr_add_rif_info(struct trh_hdr *trh, struct net_device *dev)
338 {
339         unsigned int hash, rii_p = 0;
340         unsigned long flags;
341         struct rif_cache *entry;
342         unsigned char saddr0;
343
344         spin_lock_irqsave(&rif_lock, flags);
345         saddr0 = trh->saddr[0];
346         
347         /*
348          *      Firstly see if the entry exists
349          */
350
351         if(trh->saddr[0] & TR_RII)
352         {
353                 trh->saddr[0]&=0x7f;
354                 if (((ntohs(trh->rcf) & TR_RCF_LEN_MASK) >> 8) > 2)
355                 {
356                         rii_p = 1;
357                 }
358         }
359
360         hash = rif_hash(trh->saddr);
361         for(entry=rif_table[hash];entry && memcmp(&(entry->addr[0]),&(trh->saddr[0]),TR_ALEN);entry=entry->next);
362
363         if(entry==NULL) 
364         {
365 #if TR_SR_DEBUG
366 printk("adding rif_entry: addr:%02X:%02X:%02X:%02X:%02X:%02X rcf:%04X\n",
367                 trh->saddr[0],trh->saddr[1],trh->saddr[2],
368                 trh->saddr[3],trh->saddr[4],trh->saddr[5],
369                 ntohs(trh->rcf));
370 #endif
371                 /*
372                  *      Allocate our new entry. A failure to allocate loses
373                  *      use the information. This is harmless.
374                  *
375                  *      FIXME: We ought to keep some kind of cache size
376                  *      limiting and adjust the timers to suit.
377                  */
378                 entry=kmalloc(sizeof(struct rif_cache),GFP_ATOMIC);
379
380                 if(!entry) 
381                 {
382                         printk(KERN_DEBUG "tr.c: Couldn't malloc rif cache entry !\n");
383                         spin_unlock_irqrestore(&rif_lock, flags);
384                         return;
385                 }
386
387                 memcpy(&(entry->addr[0]),&(trh->saddr[0]),TR_ALEN);
388                 entry->iface = dev->ifindex;
389                 entry->next=rif_table[hash];
390                 entry->last_used=jiffies;
391                 rif_table[hash]=entry;
392
393                 if (rii_p)
394                 {
395                         entry->rcf = trh->rcf & htons((unsigned short)~TR_RCF_BROADCAST_MASK);
396                         memcpy(&(entry->rseg[0]),&(trh->rseg[0]),8*sizeof(unsigned short));
397                         entry->local_ring = 0;
398                 }
399                 else
400                 {
401                         entry->local_ring = 1;
402                 }
403         }       
404         else    /* Y. Tahara added */
405         { 
406                 /*
407                  *      Update existing entries
408                  */
409                 if (!entry->local_ring) 
410                     if (entry->rcf != (trh->rcf & htons((unsigned short)~TR_RCF_BROADCAST_MASK)) &&
411                          !(trh->rcf & htons(TR_RCF_BROADCAST_MASK)))
412                     {
413 #if TR_SR_DEBUG
414 printk("updating rif_entry: addr:%02X:%02X:%02X:%02X:%02X:%02X rcf:%04X\n",
415                 trh->saddr[0],trh->saddr[1],trh->saddr[2],
416                 trh->saddr[3],trh->saddr[4],trh->saddr[5],
417                 ntohs(trh->rcf));
418 #endif
419                             entry->rcf = trh->rcf & htons((unsigned short)~TR_RCF_BROADCAST_MASK);
420                             memcpy(&(entry->rseg[0]),&(trh->rseg[0]),8*sizeof(unsigned short));
421                     }                                         
422                 entry->last_used=jiffies;               
423         }
424         trh->saddr[0]=saddr0; /* put the routing indicator back for tcpdump */
425         spin_unlock_irqrestore(&rif_lock, flags);
426 }
427
428 /*
429  *      Scan the cache with a timer and see what we need to throw out.
430  */
431
432 static void rif_check_expire(unsigned long dummy) 
433 {
434         int i;
435         unsigned long flags, next_interval = jiffies + sysctl_tr_rif_timeout/2;
436
437         spin_lock_irqsave(&rif_lock, flags);
438         
439         for(i =0; i < RIF_TABLE_SIZE; i++) {
440                 struct rif_cache *entry, **pentry;
441                 
442                 pentry = rif_table+i;
443                 while((entry=*pentry) != NULL) {
444                         unsigned long expires
445                                 = entry->last_used + sysctl_tr_rif_timeout;
446
447                         if (time_before_eq(expires, jiffies)) {
448                                 *pentry = entry->next;
449                                 kfree(entry);
450                         } else {
451                                 pentry = &entry->next;
452
453                                 if (time_before(expires, next_interval))
454                                         next_interval = expires;
455                         }
456                 }
457         }
458         
459         spin_unlock_irqrestore(&rif_lock, flags);
460
461         mod_timer(&rif_timer, next_interval);
462
463 }
464
465 /*
466  *      Generate the /proc/net information for the token ring RIF
467  *      routing.
468  */
469  
470 #ifdef CONFIG_PROC_FS
471
472 static struct rif_cache *rif_get_idx(loff_t pos)
473 {
474         int i;
475         struct rif_cache *entry;
476         loff_t off = 0;
477
478         for(i = 0; i < RIF_TABLE_SIZE; i++) 
479                 for(entry = rif_table[i]; entry; entry = entry->next) {
480                         if (off == pos)
481                                 return entry;
482                         ++off;
483                 }
484
485         return NULL;
486 }
487
488 static void *rif_seq_start(struct seq_file *seq, loff_t *pos)
489 {
490         spin_lock_irq(&rif_lock);
491
492         return *pos ? rif_get_idx(*pos - 1) : SEQ_START_TOKEN;
493 }
494
495 static void *rif_seq_next(struct seq_file *seq, void *v, loff_t *pos)
496 {
497         int i;
498         struct rif_cache *ent = v;
499
500         ++*pos;
501
502         if (v == SEQ_START_TOKEN) {
503                 i = -1;
504                 goto scan;
505         }
506
507         if (ent->next) 
508                 return ent->next;
509
510         i = rif_hash(ent->addr);
511  scan:
512         while (++i < RIF_TABLE_SIZE) {
513                 if ((ent = rif_table[i]) != NULL)
514                         return ent;
515         }
516         return NULL;
517 }
518
519 static void rif_seq_stop(struct seq_file *seq, void *v)
520 {
521         spin_unlock_irq(&rif_lock);
522 }
523
524 static int rif_seq_show(struct seq_file *seq, void *v)
525 {
526         int j, rcf_len, segment, brdgnmb;
527         struct rif_cache *entry = v;
528
529         if (v == SEQ_START_TOKEN)
530                 seq_puts(seq,
531                      "if     TR address       TTL   rcf   routing segments\n");
532         else {
533                 struct net_device *dev = dev_get_by_index(entry->iface);
534                 long ttl = (long) (entry->last_used + sysctl_tr_rif_timeout)
535                                 - (long) jiffies;
536
537                 seq_printf(seq, "%s %02X:%02X:%02X:%02X:%02X:%02X %7li ",
538                            dev?dev->name:"?",
539                            entry->addr[0],entry->addr[1],entry->addr[2],
540                            entry->addr[3],entry->addr[4],entry->addr[5],
541                            ttl/HZ);
542
543                         if (entry->local_ring)
544                                 seq_puts(seq, "local\n");
545                         else {
546
547                                 seq_printf(seq, "%04X", ntohs(entry->rcf));
548                                 rcf_len = ((ntohs(entry->rcf) & TR_RCF_LEN_MASK)>>8)-2; 
549                                 if (rcf_len)
550                                         rcf_len >>= 1;
551                                 for(j = 1; j < rcf_len; j++) {
552                                         if(j==1) {
553                                                 segment=ntohs(entry->rseg[j-1])>>4;
554                                                 seq_printf(seq,"  %03X",segment);
555                                         };
556                                         segment=ntohs(entry->rseg[j])>>4;
557                                         brdgnmb=ntohs(entry->rseg[j-1])&0x00f;
558                                         seq_printf(seq,"-%01X-%03X",brdgnmb,segment);
559                                 }
560                                 seq_putc(seq, '\n');
561                         }
562                 }
563         return 0;
564 }
565
566
567 static struct seq_operations rif_seq_ops = {
568         .start = rif_seq_start,
569         .next  = rif_seq_next,
570         .stop  = rif_seq_stop,
571         .show  = rif_seq_show,
572 };
573
574 static int rif_seq_open(struct inode *inode, struct file *file)
575 {
576         return seq_open(file, &rif_seq_ops);
577 }
578
579 static struct file_operations rif_seq_fops = {
580         .owner   = THIS_MODULE,
581         .open    = rif_seq_open,
582         .read    = seq_read,
583         .llseek  = seq_lseek,
584         .release = seq_release,
585 };
586
587 #endif
588
589 static void tr_setup(struct net_device *dev)
590 {
591         /*
592          *      Configure and register
593          */
594         
595         dev->hard_header        = tr_header;
596         dev->rebuild_header     = tr_rebuild_header;
597
598         dev->type               = ARPHRD_IEEE802_TR;
599         dev->hard_header_len    = TR_HLEN;
600         dev->mtu                = 2000;
601         dev->addr_len           = TR_ALEN;
602         dev->tx_queue_len       = 100;  /* Long queues on tr */
603         
604         memset(dev->broadcast,0xFF, TR_ALEN);
605
606         /* New-style flags. */
607         dev->flags              = IFF_BROADCAST | IFF_MULTICAST ;
608 }
609
610 /**
611  * alloc_trdev - Register token ring device
612  * @sizeof_priv: Size of additional driver-private structure to be allocated
613  *      for this token ring device
614  *
615  * Fill in the fields of the device structure with token ring-generic values.
616  *
617  * Constructs a new net device, complete with a private data area of
618  * size @sizeof_priv.  A 32-byte (not bit) alignment is enforced for
619  * this private data area.
620  */
621 struct net_device *alloc_trdev(int sizeof_priv)
622 {
623         return alloc_netdev(sizeof_priv, "tr%d", tr_setup);
624 }
625
626 /*
627  *      Called during bootup.  We don't actually have to initialise
628  *      too much for this.
629  */
630
631 static int __init rif_init(void)
632 {
633         init_timer(&rif_timer);
634         rif_timer.expires  = sysctl_tr_rif_timeout;
635         rif_timer.data     = 0L;
636         rif_timer.function = rif_check_expire;
637         add_timer(&rif_timer);
638
639         proc_net_fops_create("tr_rif", S_IRUGO, &rif_seq_fops);
640         return 0;
641 }
642
643 module_init(rif_init);
644
645 EXPORT_SYMBOL(tr_type_trans);
646 EXPORT_SYMBOL(alloc_trdev);