summaryrefslogtreecommitdiffstats
path: root/net/ipv6/sit.c
blob: 577b85d0fb3170bcb944bb1db816357a166b1f7f (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
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
/*
 *	IPv6 over IPv4 tunnel device - Simple Internet Transition (SIT)
 *	Linux INET6 implementation
 *
 *	Authors:
 *	Pedro Roque		<roque@di.fc.ul.pt>	
 *	Alexey Kuznetsov	<kuznet@ms2.inr.ac.ru>
 *
 *	$Id: sit.c,v 1.27 1998/03/08 05:56:57 davem Exp $
 *
 *	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.
 */

#define __NO_VERSION__
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/sched.h>
#include <linux/net.h>
#include <linux/in6.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/icmp.h>
#include <asm/uaccess.h>
#include <linux/init.h>

#include <net/sock.h>
#include <net/snmp.h>

#include <net/ipv6.h>
#include <net/protocol.h>
#include <net/transp_v6.h>
#include <net/ip6_fib.h>
#include <net/ip6_route.h>
#include <net/ndisc.h>
#include <net/addrconf.h>
#include <net/ip.h>
#include <net/udp.h>
#include <net/icmp.h>
#include <net/ipip.h>

/*
   This version of net/ipv6/sit.c is cloned of net/ipv4/ip_gre.c

   For comments look at net/ipv4/ip_gre.c --ANK
 */

#define HASH_SIZE  16
#define HASH(addr) ((addr^(addr>>4))&0xF)

static int ipip6_fb_tunnel_init(struct device *dev);
static int ipip6_tunnel_init(struct device *dev);

static struct device ipip6_fb_tunnel_dev = {
	NULL, 0x0, 0x0, 0x0, 0x0, 0, 0, 0, 0, 0, NULL, ipip6_fb_tunnel_init,
};

static struct ip_tunnel ipip6_fb_tunnel = {
	NULL, &ipip6_fb_tunnel_dev, {0, }, 0, 0, 0, 0, 0, 0, 0, {"sit0", }
};

static struct ip_tunnel *tunnels_r_l[HASH_SIZE];
static struct ip_tunnel *tunnels_r[HASH_SIZE];
static struct ip_tunnel *tunnels_l[HASH_SIZE];
static struct ip_tunnel *tunnels_wc[1];
static struct ip_tunnel **tunnels[4] = { tunnels_wc, tunnels_l, tunnels_r, tunnels_r_l };

static struct ip_tunnel * ipip6_tunnel_lookup(u32 remote, u32 local)
{
	unsigned h0 = HASH(remote);
	unsigned h1 = HASH(local);
	struct ip_tunnel *t;

	for (t = tunnels_r_l[h0^h1]; t; t = t->next) {
		if (local == t->parms.iph.saddr &&
		    remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
			return t;
	}
	for (t = tunnels_r[h0]; t; t = t->next) {
		if (remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
			return t;
	}
	for (t = tunnels_l[h1]; t; t = t->next) {
		if (local == t->parms.iph.saddr && (t->dev->flags&IFF_UP))
			return t;
	}
	if ((t = tunnels_wc[0]) != NULL && (t->dev->flags&IFF_UP))
		return t;
	return NULL;
}

struct ip_tunnel * ipip6_tunnel_locate(struct ip_tunnel_parm *parms, int create)
{
	u32 remote = parms->iph.daddr;
	u32 local = parms->iph.saddr;
	struct ip_tunnel *t, **tp, *nt;
	struct device *dev;
	unsigned h = 0;
	int prio = 0;

	if (remote) {
		prio |= 2;
		h ^= HASH(remote);
	}
	if (local) {
		prio |= 1;
		h ^= HASH(local);
	}
	for (tp = &tunnels[prio][h]; (t = *tp) != NULL; tp = &t->next) {
		if (local == t->parms.iph.saddr && remote == t->parms.iph.daddr)
			return t;
	}
	if (!create)
		return NULL;

	MOD_INC_USE_COUNT;
	dev = kmalloc(sizeof(*dev) + sizeof(*t), GFP_KERNEL);
	if (dev == NULL) {
		MOD_DEC_USE_COUNT;
		return NULL;
	}
	memset(dev, 0, sizeof(*dev) + sizeof(*t));
	dev->priv = (void*)(dev+1);
	nt = (struct ip_tunnel*)dev->priv;
	nt->dev = dev;
	dev->name = nt->parms.name;
	dev->init = ipip6_tunnel_init;
	memcpy(&nt->parms, parms, sizeof(*parms));
	if (dev->name[0] == 0) {
		int i;
		for (i=1; i<100; i++) {
			sprintf(dev->name, "sit%d", i);
			if (dev_get(dev->name) == NULL)
				break;
		}
		if (i==100)
			goto failed;
		memcpy(parms->name, dev->name, IFNAMSIZ);
	}
	if (register_netdevice(dev) < 0)
		goto failed;

	start_bh_atomic();
	nt->next = t;
	*tp = nt;
	end_bh_atomic();
	/* Do not decrement MOD_USE_COUNT here. */
	return nt;

failed:
	kfree(dev);
	MOD_DEC_USE_COUNT;
	return NULL;
}

static void ipip6_tunnel_destroy(struct device *dev)
{
	struct ip_tunnel *t, **tp;
	struct ip_tunnel *t0 = (struct ip_tunnel*)dev->priv;
	u32 remote = t0->parms.iph.daddr;
	u32 local = t0->parms.iph.saddr;
	unsigned h = 0;
	int prio = 0;

	if (dev == &ipip6_fb_tunnel_dev) {
		tunnels_wc[0] = NULL;
		return;
	}

	if (remote) {
		prio |= 2;
		h ^= HASH(remote);
	}
	if (local) {
		prio |= 1;
		h ^= HASH(local);
	}
	for (tp = &tunnels[prio][h]; (t = *tp) != NULL; tp = &t->next) {
		if (t == t0) {
			*tp = t->next;
			kfree(dev);
			MOD_DEC_USE_COUNT;
			break;
		}
	}
}


void ipip6_err(struct sk_buff *skb, unsigned char *dp, int len)
{
#ifndef I_WISH_WORLD_WERE_PERFECT

/* It is not :-( All the routers (except for Linux) return only
   8 bytes of packet payload. It means, that precise relaying of
   ICMP in the real Internet is absolutely infeasible.
 */
	struct iphdr *iph = (struct iphdr*)dp;
	int type = skb->h.icmph->type;
	int code = skb->h.icmph->code;
	struct ip_tunnel *t;

	if (len < sizeof(struct iphdr))
		return;

	switch (type) {
	default:
	case ICMP_PARAMETERPROB:
		return;

	case ICMP_DEST_UNREACH:
		switch (code) {
		case ICMP_SR_FAILED:
		case ICMP_PORT_UNREACH:
			/* Impossible event. */
			return;
		case ICMP_FRAG_NEEDED:
			/* Soft state for pmtu is maintained by IP core. */
			return;
		default:
			/* All others are translated to HOST_UNREACH.
			   rfc2003 contains "deep thoughts" about NET_UNREACH,
			   I believe they are just ether pollution. --ANK
			 */
			break;
		}
		break;
	case ICMP_TIME_EXCEEDED:
		if (code != ICMP_EXC_TTL)
			return;
		break;
	}

	t = ipip6_tunnel_lookup(iph->daddr, iph->saddr);
	if (t == NULL || t->parms.iph.daddr == 0)
		return;
	if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
		return;

	if (jiffies - t->err_time < IPTUNNEL_ERR_TIMEO)
		t->err_count++;
	else
		t->err_count = 1;
	t->err_time = jiffies;
	return;
#else
	struct iphdr *iph = (struct iphdr*)dp;
	int hlen = iph->ihl<<2;
	struct ipv6hdr *iph6;
	int type = skb->h.icmph->type;
	int code = skb->h.icmph->code;
	int rel_type = 0;
	int rel_code = 0;
	int rel_info = 0;
	struct sk_buff *skb2;
	struct rt6_info *rt6i;

	if (len < hlen + sizeof(struct ipv6hdr))
		return;
	iph6 = (struct ipv6hdr*)(dp + hlen);

	switch (type) {
	default:
		return;
	case ICMP_PARAMETERPROB:
		if (skb->h.icmph->un.gateway < hlen)
			return;

		/* So... This guy found something strange INSIDE encapsulated
		   packet. Well, he is fool, but what can we do ?
		 */
		rel_type = ICMPV6_PARAMPROB;
		rel_info = skb->h.icmph->un.gateway - hlen;
		break;

	case ICMP_DEST_UNREACH:
		switch (code) {
		case ICMP_SR_FAILED:
		case ICMP_PORT_UNREACH:
			/* Impossible event. */
			return;
		case ICMP_FRAG_NEEDED:
			/* Too complicated case ... */
			return;
		default:
			/* All others are translated to HOST_UNREACH.
			   rfc2003 contains "deep thoughts" about NET_UNREACH,
			   I believe, it is just ether pollution. --ANK
			 */
			rel_type = ICMPV6_DEST_UNREACH;
			rel_code = ICMPV6_ADDR_UNREACH;
			break;
		}
		break;
	case ICMP_TIME_EXCEEDED:
		if (code != ICMP_EXC_TTL)
			return;
		rel_type = ICMPV6_TIME_EXCEED;
		rel_code = ICMPV6_EXC_HOPLIMIT;
		break;
	}

	/* Prepare fake skb to feed it to icmpv6_send */
	skb2 = skb_clone(skb, GFP_ATOMIC);
	if (skb2 == NULL)
		return;
	dst_release(skb2->dst);
	skb2->dst = NULL;
	skb_pull(skb2, skb->data - (u8*)iph6);
	skb2->nh.raw = skb2->data;

	/* Try to guess incoming interface */
	rt6i = rt6_lookup(&iph6->saddr, NULL, NULL, 0);
	if (rt6i && rt6i->rt6i_dev) {
		skb2->dev = rt6i->rt6i_dev;

		rt6i = rt6_lookup(&iph6->daddr, &iph6->saddr, NULL, 0);

		if (rt6i && rt6i->rt6i_dev && rt6i->rt6i_dev->type == ARPHRD_SIT) {
			struct ip_tunnel * t = (struct ip_tunnel*)rt6i->rt6i_dev->priv;
			if (rel_type == ICMPV6_TIME_EXCEED && t->parms.iph.ttl) {
				rel_type = ICMPV6_DEST_UNREACH;
				rel_code = ICMPV6_ADDR_UNREACH;
			}
			icmpv6_send(skb2, rel_type, rel_code, rel_info, skb2->dev);
		}
	}
	kfree_skb(skb2);
	return;
#endif
}

int ipip6_rcv(struct sk_buff *skb, unsigned short len)
{
	struct iphdr *iph;
	struct ip_tunnel *tunnel;

	iph = skb->nh.iph;

	if ((tunnel = ipip6_tunnel_lookup(iph->saddr, iph->daddr)) != NULL) {
		skb->mac.raw = skb->nh.raw;
		skb->nh.raw = skb_pull(skb, skb->h.raw - skb->data);
		memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options));
		skb->protocol = __constant_htons(ETH_P_IPV6);
		skb->ip_summed = 0;
		skb->pkt_type = PACKET_HOST;
		tunnel->stat.rx_packets++;
		tunnel->stat.rx_bytes += skb->len;
		skb->dev = tunnel->dev;
		dst_release(skb->dst);
		skb->dst = NULL;
		netif_rx(skb);
		return 0;
	}

	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PROT_UNREACH, 0);
	kfree_skb(skb);
	return 0;
}

/*
 *	This function assumes it is being called from dev_queue_xmit()
 *	and that skb is filled properly by that function.
 */

static int ipip6_tunnel_xmit(struct sk_buff *skb, struct device *dev)
{
	struct ip_tunnel *tunnel = (struct ip_tunnel*)dev->priv;
	struct net_device_stats *stats = &tunnel->stat;
	struct iphdr  *tiph = &tunnel->parms.iph;
	struct ipv6hdr *iph6 = skb->nh.ipv6h;
	u8     tos = tunnel->parms.iph.tos;
	struct rtable *rt;     			/* Route to the other host */
	struct device *tdev;			/* Device to other host */
	struct iphdr  *iph;			/* Our new IP header */
	int    max_headroom;			/* The extra header space needed */
	u32    dst = tiph->daddr;
	int    mtu;
	struct in6_addr *addr6;	
	int addr_type;

	if (tunnel->recursion++) {
		tunnel->stat.collisions++;
		goto tx_error;
	}

	if (skb->protocol != __constant_htons(ETH_P_IPV6))
		goto tx_error;

	if (!dst) {
		struct neighbour *neigh = NULL;

		if (skb->dst)
			neigh = skb->dst->neighbour;

		if (neigh == NULL) {
			printk(KERN_DEBUG "sit: nexthop == NULL\n");
			goto tx_error;
		}

		addr6 = (struct in6_addr*)&neigh->primary_key;
		addr_type = ipv6_addr_type(addr6);

		if (addr_type == IPV6_ADDR_ANY) {
			addr6 = &skb->nh.ipv6h->daddr;
			addr_type = ipv6_addr_type(addr6);
		}

		if ((addr_type & IPV6_ADDR_COMPATv4) == 0)
			goto tx_error_icmp;

		dst = addr6->s6_addr32[3];
	}

	if (ip_route_output(&rt, dst, tiph->saddr, RT_TOS(tos), tunnel->parms.link)) {
		tunnel->stat.tx_carrier_errors++;
		goto tx_error_icmp;
	}
	tdev = rt->u.dst.dev;

	if (tdev == dev) {
		ip_rt_put(rt);
		tunnel->stat.collisions++;
		goto tx_error;
	}

	mtu = rt->u.dst.pmtu - sizeof(struct iphdr);
	if (mtu < 68) {
		tunnel->stat.collisions++;
		ip_rt_put(rt);
		goto tx_error;
	}
	if (mtu >= 576) {
		if (skb->dst && mtu < skb->dst->pmtu) {
			struct rt6_info *rt6 = (struct rt6_info*)skb->dst;
			if (mtu < rt6->u.dst.pmtu) {
				if (tunnel->parms.iph.daddr || rt6->rt6i_dst.plen == 128) {
					rt6->rt6i_flags |= RTF_MODIFIED;
					rt6->u.dst.pmtu = mtu;
				}
			}
		}
		if (skb->len > mtu) {
			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, dev);
			ip_rt_put(rt);
			goto tx_error;
		}
	}

	if (tunnel->err_count > 0) {
		if (jiffies - tunnel->err_time < IPTUNNEL_ERR_TIMEO) {
			tunnel->err_count--;
			dst_link_failure(skb);
		} else
			tunnel->err_count = 0;
	}

	skb->h.raw = skb->nh.raw;

	/*
	 * Okay, now see if we can stuff it in the buffer as-is.
	 */
	max_headroom = (((tdev->hard_header_len+15)&~15)+sizeof(struct iphdr));

	if (skb_headroom(skb) < max_headroom || skb_cloned(skb) || skb_shared(skb)) {
		struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
		if (!new_skb) {
			ip_rt_put(rt);
  			stats->tx_dropped++;
			dev_kfree_skb(skb);
			tunnel->recursion--;
			return 0;
		}
		dev_kfree_skb(skb);
		skb = new_skb;
	}

	skb->nh.raw = skb_push(skb, sizeof(struct iphdr));
	memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
	dst_release(skb->dst);
	skb->dst = &rt->u.dst;

	/*
	 *	Push down and install the IPIP header.
	 */

	iph 			=	skb->nh.iph;
	iph->version		=	4;
	iph->ihl		=	sizeof(struct iphdr)>>2;
	if (mtu > 576)
		iph->frag_off	=	__constant_htons(IP_DF);
	else
		iph->frag_off	=	0;

	iph->protocol		=	IPPROTO_IPV6;
	iph->tos		=	tos;
	iph->daddr		=	rt->rt_dst;
	iph->saddr		=	rt->rt_src;

	if ((iph->ttl = tiph->ttl) == 0)
		iph->ttl	=	iph6->hop_limit;

	iph->tot_len		=	htons(skb->len);
	iph->id			=	htons(ip_id_count++);
	ip_send_check(iph);

	stats->tx_bytes += skb->len;
	stats->tx_packets++;
	ip_send(skb);

	tunnel->recursion--;
	return 0;

tx_error_icmp:
	dst_link_failure(skb);
tx_error:
	stats->tx_errors++;
	dev_kfree_skb(skb);
	tunnel->recursion--;
	return 0;
}

static int
ipip6_tunnel_ioctl (struct device *dev, struct ifreq *ifr, int cmd)
{
	int err = 0;
	struct ip_tunnel_parm p;
	struct ip_tunnel *t;

	MOD_INC_USE_COUNT;

	switch (cmd) {
	case SIOCGETTUNNEL:
		t = NULL;
		if (dev == &ipip6_fb_tunnel_dev) {
			if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
				err = -EFAULT;
				break;
			}
			t = ipip6_tunnel_locate(&p, 0);
		}
		if (t == NULL)
			t = (struct ip_tunnel*)dev->priv;
		memcpy(&p, &t->parms, sizeof(p));
		if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
			err = -EFAULT;
		break;

	case SIOCADDTUNNEL:
	case SIOCCHGTUNNEL:
		err = -EFAULT;
		if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
			goto done;

		err = -EINVAL;
		if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPV6 ||
		    p.iph.ihl != 5 || (p.iph.frag_off&__constant_htons(~IP_DF)))
			goto done;
		if (p.iph.ttl)
			p.iph.frag_off |= __constant_htons(IP_DF);

		t = ipip6_tunnel_locate(&p, cmd == SIOCADDTUNNEL);

		if (t) {
			err = 0;
			if (cmd == SIOCCHGTUNNEL) {
				t->parms.iph.ttl = p.iph.ttl;
				t->parms.iph.tos = p.iph.tos;
			}
			if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
				err = -EFAULT;
		} else
			err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
		break;

	case SIOCDELTUNNEL:
		if (dev == &ipip6_fb_tunnel_dev) {
			err = -EFAULT;
			if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
				goto done;
			err = -ENOENT;
			if ((t = ipip6_tunnel_locate(&p, 0)) == NULL)
				goto done;
			err = -EPERM;
			if (t == &ipip6_fb_tunnel)
				goto done;
		}
		err = unregister_netdevice(dev);
		break;

	default:
		err = -EINVAL;
	}

done:
	MOD_DEC_USE_COUNT;
	return err;
}

static struct net_device_stats *ipip6_tunnel_get_stats(struct device *dev)
{
	return &(((struct ip_tunnel*)dev->priv)->stat);
}

static int ipip6_tunnel_change_mtu(struct device *dev, int new_mtu)
{
	if (new_mtu < 576 || new_mtu > 0xFFF8 - sizeof(struct iphdr))
		return -EINVAL;
	dev->mtu = new_mtu;
	return 0;
}

static void ipip6_tunnel_init_gen(struct device *dev)
{
	struct ip_tunnel *t = (struct ip_tunnel*)dev->priv;

	dev->destructor		= ipip6_tunnel_destroy;
	dev->hard_start_xmit	= ipip6_tunnel_xmit;
	dev->get_stats		= ipip6_tunnel_get_stats;
	dev->do_ioctl		= ipip6_tunnel_ioctl;
	dev->change_mtu		= ipip6_tunnel_change_mtu;

	dev_init_buffers(dev);

	dev->type		= ARPHRD_SIT;
	dev->hard_header_len 	= LL_MAX_HEADER + sizeof(struct iphdr);
	dev->mtu		= 1500 - sizeof(struct iphdr);
	dev->flags		= IFF_NOARP;
	dev->iflink		= 0;
	dev->addr_len		= 4;
	memcpy(dev->dev_addr, &t->parms.iph.saddr, 4);
	memcpy(dev->broadcast, &t->parms.iph.daddr, 4);
}

static int ipip6_tunnel_init(struct device *dev)
{
	struct device *tdev = NULL;
	struct ip_tunnel *tunnel;
	struct iphdr *iph;

	tunnel = (struct ip_tunnel*)dev->priv;
	iph = &tunnel->parms.iph;

	ipip6_tunnel_init_gen(dev);

	if (iph->daddr) {
		struct rtable *rt;
		if (!ip_route_output(&rt, iph->daddr, iph->saddr, RT_TOS(iph->tos), tunnel->parms.link)) {
			tdev = rt->u.dst.dev;
			ip_rt_put(rt);
		}
		dev->flags |= IFF_POINTOPOINT;
	}

	if (!tdev && tunnel->parms.link)
		tdev = dev_get_by_index(tunnel->parms.link);

	if (tdev) {
		dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
		dev->mtu = tdev->mtu - sizeof(struct iphdr);
		if (dev->mtu < 576)
			dev->mtu = 576;
	}
	dev->iflink = tunnel->parms.link;

	return 0;
}

#ifdef MODULE
static int ipip6_fb_tunnel_open(struct device *dev)
{
	MOD_INC_USE_COUNT;
	return 0;
}

static int ipip6_fb_tunnel_close(struct device *dev)
{
	MOD_DEC_USE_COUNT;
	return 0;
}
#endif

__initfunc(int ipip6_fb_tunnel_init(struct device *dev))
{
	struct iphdr *iph;

	ipip6_tunnel_init_gen(dev);
#ifdef MODULE
	dev->open		= ipip6_fb_tunnel_open;
	dev->stop		= ipip6_fb_tunnel_close;
#endif

	iph = &ipip6_fb_tunnel.parms.iph;
	iph->version		= 4;
	iph->protocol		= IPPROTO_IPV6;
	iph->ihl		= 5;
	iph->ttl		= 64;

	tunnels_wc[0]		= &ipip6_fb_tunnel;
	return 0;
}

static struct inet_protocol sit_protocol = {
	ipip6_rcv,
	ipip6_err,
	0,
	IPPROTO_IPV6,
	0,
	NULL,
	"IPv6"
};

#ifdef MODULE
void sit_cleanup(void)
{
	inet_del_protocol(&sit_protocol);
	unregister_netdevice(&ipip6_fb_tunnel_dev);
}
#endif

__initfunc(int sit_init(void))
{
	printk(KERN_INFO "IPv6 over IPv4 tunneling driver\n");

	ipip6_fb_tunnel_dev.priv = (void*)&ipip6_fb_tunnel;
	ipip6_fb_tunnel_dev.name = ipip6_fb_tunnel.parms.name;
#ifdef MODULE
	register_netdev(&ipip6_fb_tunnel_dev);
#else
	register_netdevice(&ipip6_fb_tunnel_dev);
#endif
	inet_add_protocol(&sit_protocol);
	return 0;
}