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ipsec: Interfamily IPSec BEET, ipv4-inner ipv6-outer
[linux-2.6] / net / ipv6 / sit.c
1 /*
2  *      IPv6 over IPv4 tunnel device - Simple Internet Transition (SIT)
3  *      Linux INET6 implementation
4  *
5  *      Authors:
6  *      Pedro Roque             <roque@di.fc.ul.pt>
7  *      Alexey Kuznetsov        <kuznet@ms2.inr.ac.ru>
8  *
9  *      This program is free software; you can redistribute it and/or
10  *      modify it under the terms of the GNU General Public License
11  *      as published by the Free Software Foundation; either version
12  *      2 of the License, or (at your option) any later version.
13  *
14  *      Changes:
15  * Roger Venning <r.venning@telstra.com>:       6to4 support
16  * Nate Thompson <nate@thebog.net>:             6to4 support
17  * Fred Templin <fred.l.templin@boeing.com>:    isatap support
18  */
19
20 #include <linux/module.h>
21 #include <linux/capability.h>
22 #include <linux/errno.h>
23 #include <linux/types.h>
24 #include <linux/socket.h>
25 #include <linux/sockios.h>
26 #include <linux/net.h>
27 #include <linux/in6.h>
28 #include <linux/netdevice.h>
29 #include <linux/if_arp.h>
30 #include <linux/icmp.h>
31 #include <asm/uaccess.h>
32 #include <linux/init.h>
33 #include <linux/netfilter_ipv4.h>
34 #include <linux/if_ether.h>
35
36 #include <net/sock.h>
37 #include <net/snmp.h>
38
39 #include <net/ipv6.h>
40 #include <net/protocol.h>
41 #include <net/transp_v6.h>
42 #include <net/ip6_fib.h>
43 #include <net/ip6_route.h>
44 #include <net/ndisc.h>
45 #include <net/addrconf.h>
46 #include <net/ip.h>
47 #include <net/udp.h>
48 #include <net/icmp.h>
49 #include <net/ipip.h>
50 #include <net/inet_ecn.h>
51 #include <net/xfrm.h>
52 #include <net/dsfield.h>
53 #include <net/net_namespace.h>
54 #include <net/netns/generic.h>
55
56 /*
57    This version of net/ipv6/sit.c is cloned of net/ipv4/ip_gre.c
58
59    For comments look at net/ipv4/ip_gre.c --ANK
60  */
61
62 #define HASH_SIZE  16
63 #define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
64
65 static int ipip6_fb_tunnel_init(struct net_device *dev);
66 static int ipip6_tunnel_init(struct net_device *dev);
67 static void ipip6_tunnel_setup(struct net_device *dev);
68
69 static int sit_net_id;
70 struct sit_net {
71         struct ip_tunnel *tunnels_r_l[HASH_SIZE];
72         struct ip_tunnel *tunnels_r[HASH_SIZE];
73         struct ip_tunnel *tunnels_l[HASH_SIZE];
74         struct ip_tunnel *tunnels_wc[1];
75         struct ip_tunnel **tunnels[4];
76
77         struct net_device *fb_tunnel_dev;
78 };
79
80 static DEFINE_RWLOCK(ipip6_lock);
81
82 static struct ip_tunnel * ipip6_tunnel_lookup(struct net *net,
83                 __be32 remote, __be32 local)
84 {
85         unsigned h0 = HASH(remote);
86         unsigned h1 = HASH(local);
87         struct ip_tunnel *t;
88         struct sit_net *sitn = net_generic(net, sit_net_id);
89
90         for (t = sitn->tunnels_r_l[h0^h1]; t; t = t->next) {
91                 if (local == t->parms.iph.saddr &&
92                     remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
93                         return t;
94         }
95         for (t = sitn->tunnels_r[h0]; t; t = t->next) {
96                 if (remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
97                         return t;
98         }
99         for (t = sitn->tunnels_l[h1]; t; t = t->next) {
100                 if (local == t->parms.iph.saddr && (t->dev->flags&IFF_UP))
101                         return t;
102         }
103         if ((t = sitn->tunnels_wc[0]) != NULL && (t->dev->flags&IFF_UP))
104                 return t;
105         return NULL;
106 }
107
108 static struct ip_tunnel **__ipip6_bucket(struct sit_net *sitn,
109                 struct ip_tunnel_parm *parms)
110 {
111         __be32 remote = parms->iph.daddr;
112         __be32 local = parms->iph.saddr;
113         unsigned h = 0;
114         int prio = 0;
115
116         if (remote) {
117                 prio |= 2;
118                 h ^= HASH(remote);
119         }
120         if (local) {
121                 prio |= 1;
122                 h ^= HASH(local);
123         }
124         return &sitn->tunnels[prio][h];
125 }
126
127 static inline struct ip_tunnel **ipip6_bucket(struct sit_net *sitn,
128                 struct ip_tunnel *t)
129 {
130         return __ipip6_bucket(sitn, &t->parms);
131 }
132
133 static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
134 {
135         struct ip_tunnel **tp;
136
137         for (tp = ipip6_bucket(sitn, t); *tp; tp = &(*tp)->next) {
138                 if (t == *tp) {
139                         write_lock_bh(&ipip6_lock);
140                         *tp = t->next;
141                         write_unlock_bh(&ipip6_lock);
142                         break;
143                 }
144         }
145 }
146
147 static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
148 {
149         struct ip_tunnel **tp = ipip6_bucket(sitn, t);
150
151         t->next = *tp;
152         write_lock_bh(&ipip6_lock);
153         *tp = t;
154         write_unlock_bh(&ipip6_lock);
155 }
156
157 static struct ip_tunnel * ipip6_tunnel_locate(struct net *net,
158                 struct ip_tunnel_parm *parms, int create)
159 {
160         __be32 remote = parms->iph.daddr;
161         __be32 local = parms->iph.saddr;
162         struct ip_tunnel *t, **tp, *nt;
163         struct net_device *dev;
164         char name[IFNAMSIZ];
165         struct sit_net *sitn = net_generic(net, sit_net_id);
166
167         for (tp = __ipip6_bucket(sitn, parms); (t = *tp) != NULL; tp = &t->next) {
168                 if (local == t->parms.iph.saddr && remote == t->parms.iph.daddr)
169                         return t;
170         }
171         if (!create)
172                 goto failed;
173
174         if (parms->name[0])
175                 strlcpy(name, parms->name, IFNAMSIZ);
176         else
177                 sprintf(name, "sit%%d");
178
179         dev = alloc_netdev(sizeof(*t), name, ipip6_tunnel_setup);
180         if (dev == NULL)
181                 return NULL;
182
183         dev_net_set(dev, net);
184
185         if (strchr(name, '%')) {
186                 if (dev_alloc_name(dev, name) < 0)
187                         goto failed_free;
188         }
189
190         nt = netdev_priv(dev);
191         dev->init = ipip6_tunnel_init;
192         nt->parms = *parms;
193
194         if (parms->i_flags & SIT_ISATAP)
195                 dev->priv_flags |= IFF_ISATAP;
196
197         if (register_netdevice(dev) < 0)
198                 goto failed_free;
199
200         dev_hold(dev);
201
202         ipip6_tunnel_link(sitn, nt);
203         return nt;
204
205 failed_free:
206         free_netdev(dev);
207 failed:
208         return NULL;
209 }
210
211 static struct ip_tunnel_prl_entry *
212 __ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
213 {
214         struct ip_tunnel_prl_entry *p = (struct ip_tunnel_prl_entry *)NULL;
215
216         for (p = t->prl; p; p = p->next)
217                 if (p->addr == addr)
218                         break;
219         return p;
220
221 }
222
223 static int ipip6_tunnel_get_prl(struct ip_tunnel *t,
224                                 struct ip_tunnel_prl __user *a)
225 {
226         struct ip_tunnel_prl kprl, *kp;
227         struct ip_tunnel_prl_entry *prl;
228         unsigned int cmax, c = 0, ca, len;
229         int ret = 0;
230
231         if (copy_from_user(&kprl, a, sizeof(kprl)))
232                 return -EFAULT;
233         cmax = kprl.datalen / sizeof(kprl);
234         if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
235                 cmax = 1;
236
237         /* For simple GET or for root users,
238          * we try harder to allocate.
239          */
240         kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
241                 kcalloc(cmax, sizeof(*kp), GFP_KERNEL) :
242                 NULL;
243
244         read_lock(&ipip6_lock);
245
246         ca = t->prl_count < cmax ? t->prl_count : cmax;
247
248         if (!kp) {
249                 /* We don't try hard to allocate much memory for
250                  * non-root users.
251                  * For root users, retry allocating enough memory for
252                  * the answer.
253                  */
254                 kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
255                 if (!kp) {
256                         ret = -ENOMEM;
257                         goto out;
258                 }
259         }
260
261         c = 0;
262         for (prl = t->prl; prl; prl = prl->next) {
263                 if (c > cmax)
264                         break;
265                 if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
266                         continue;
267                 kp[c].addr = prl->addr;
268                 kp[c].flags = prl->flags;
269                 c++;
270                 if (kprl.addr != htonl(INADDR_ANY))
271                         break;
272         }
273 out:
274         read_unlock(&ipip6_lock);
275
276         len = sizeof(*kp) * c;
277         ret = 0;
278         if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
279                 ret = -EFAULT;
280
281         kfree(kp);
282
283         return ret;
284 }
285
286 static int
287 ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
288 {
289         struct ip_tunnel_prl_entry *p;
290         int err = 0;
291
292         if (a->addr == htonl(INADDR_ANY))
293                 return -EINVAL;
294
295         write_lock(&ipip6_lock);
296
297         for (p = t->prl; p; p = p->next) {
298                 if (p->addr == a->addr) {
299                         if (chg)
300                                 goto update;
301                         err = -EEXIST;
302                         goto out;
303                 }
304         }
305
306         if (chg) {
307                 err = -ENXIO;
308                 goto out;
309         }
310
311         p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
312         if (!p) {
313                 err = -ENOBUFS;
314                 goto out;
315         }
316
317         p->next = t->prl;
318         t->prl = p;
319         t->prl_count++;
320 update:
321         p->addr = a->addr;
322         p->flags = a->flags;
323 out:
324         write_unlock(&ipip6_lock);
325         return err;
326 }
327
328 static int
329 ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
330 {
331         struct ip_tunnel_prl_entry *x, **p;
332         int err = 0;
333
334         write_lock(&ipip6_lock);
335
336         if (a && a->addr != htonl(INADDR_ANY)) {
337                 for (p = &t->prl; *p; p = &(*p)->next) {
338                         if ((*p)->addr == a->addr) {
339                                 x = *p;
340                                 *p = x->next;
341                                 kfree(x);
342                                 t->prl_count--;
343                                 goto out;
344                         }
345                 }
346                 err = -ENXIO;
347         } else {
348                 while (t->prl) {
349                         x = t->prl;
350                         t->prl = t->prl->next;
351                         kfree(x);
352                         t->prl_count--;
353                 }
354         }
355 out:
356         write_unlock(&ipip6_lock);
357         return 0;
358 }
359
360 static int
361 isatap_chksrc(struct sk_buff *skb, struct iphdr *iph, struct ip_tunnel *t)
362 {
363         struct ip_tunnel_prl_entry *p;
364         int ok = 1;
365
366         read_lock(&ipip6_lock);
367         p = __ipip6_tunnel_locate_prl(t, iph->saddr);
368         if (p) {
369                 if (p->flags & PRL_DEFAULT)
370                         skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
371                 else
372                         skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
373         } else {
374                 struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
375                 if (ipv6_addr_is_isatap(addr6) &&
376                     (addr6->s6_addr32[3] == iph->saddr) &&
377                     ipv6_chk_prefix(addr6, t->dev))
378                         skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
379                 else
380                         ok = 0;
381         }
382         read_unlock(&ipip6_lock);
383         return ok;
384 }
385
386 static void ipip6_tunnel_uninit(struct net_device *dev)
387 {
388         struct net *net = dev_net(dev);
389         struct sit_net *sitn = net_generic(net, sit_net_id);
390
391         if (dev == sitn->fb_tunnel_dev) {
392                 write_lock_bh(&ipip6_lock);
393                 sitn->tunnels_wc[0] = NULL;
394                 write_unlock_bh(&ipip6_lock);
395                 dev_put(dev);
396         } else {
397                 ipip6_tunnel_unlink(sitn, netdev_priv(dev));
398                 ipip6_tunnel_del_prl(netdev_priv(dev), NULL);
399                 dev_put(dev);
400         }
401 }
402
403
404 static int ipip6_err(struct sk_buff *skb, u32 info)
405 {
406
407 /* All the routers (except for Linux) return only
408    8 bytes of packet payload. It means, that precise relaying of
409    ICMP in the real Internet is absolutely infeasible.
410  */
411         struct iphdr *iph = (struct iphdr*)skb->data;
412         const int type = icmp_hdr(skb)->type;
413         const int code = icmp_hdr(skb)->code;
414         struct ip_tunnel *t;
415         int err;
416
417         switch (type) {
418         default:
419         case ICMP_PARAMETERPROB:
420                 return 0;
421
422         case ICMP_DEST_UNREACH:
423                 switch (code) {
424                 case ICMP_SR_FAILED:
425                 case ICMP_PORT_UNREACH:
426                         /* Impossible event. */
427                         return 0;
428                 case ICMP_FRAG_NEEDED:
429                         /* Soft state for pmtu is maintained by IP core. */
430                         return 0;
431                 default:
432                         /* All others are translated to HOST_UNREACH.
433                            rfc2003 contains "deep thoughts" about NET_UNREACH,
434                            I believe they are just ether pollution. --ANK
435                          */
436                         break;
437                 }
438                 break;
439         case ICMP_TIME_EXCEEDED:
440                 if (code != ICMP_EXC_TTL)
441                         return 0;
442                 break;
443         }
444
445         err = -ENOENT;
446
447         read_lock(&ipip6_lock);
448         t = ipip6_tunnel_lookup(dev_net(skb->dev), iph->daddr, iph->saddr);
449         if (t == NULL || t->parms.iph.daddr == 0)
450                 goto out;
451
452         err = 0;
453         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
454                 goto out;
455
456         if (jiffies - t->err_time < IPTUNNEL_ERR_TIMEO)
457                 t->err_count++;
458         else
459                 t->err_count = 1;
460         t->err_time = jiffies;
461 out:
462         read_unlock(&ipip6_lock);
463         return err;
464 }
465
466 static inline void ipip6_ecn_decapsulate(struct iphdr *iph, struct sk_buff *skb)
467 {
468         if (INET_ECN_is_ce(iph->tos))
469                 IP6_ECN_set_ce(ipv6_hdr(skb));
470 }
471
472 static int ipip6_rcv(struct sk_buff *skb)
473 {
474         struct iphdr *iph;
475         struct ip_tunnel *tunnel;
476
477         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
478                 goto out;
479
480         iph = ip_hdr(skb);
481
482         read_lock(&ipip6_lock);
483         if ((tunnel = ipip6_tunnel_lookup(dev_net(skb->dev),
484                                         iph->saddr, iph->daddr)) != NULL) {
485                 secpath_reset(skb);
486                 skb->mac_header = skb->network_header;
487                 skb_reset_network_header(skb);
488                 IPCB(skb)->flags = 0;
489                 skb->protocol = htons(ETH_P_IPV6);
490                 skb->pkt_type = PACKET_HOST;
491
492                 if ((tunnel->dev->priv_flags & IFF_ISATAP) &&
493                     !isatap_chksrc(skb, iph, tunnel)) {
494                         tunnel->dev->stats.rx_errors++;
495                         read_unlock(&ipip6_lock);
496                         kfree_skb(skb);
497                         return 0;
498                 }
499                 tunnel->dev->stats.rx_packets++;
500                 tunnel->dev->stats.rx_bytes += skb->len;
501                 skb->dev = tunnel->dev;
502                 dst_release(skb->dst);
503                 skb->dst = NULL;
504                 nf_reset(skb);
505                 ipip6_ecn_decapsulate(iph, skb);
506                 netif_rx(skb);
507                 read_unlock(&ipip6_lock);
508                 return 0;
509         }
510
511         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
512         read_unlock(&ipip6_lock);
513 out:
514         kfree_skb(skb);
515         return 0;
516 }
517
518 /* Returns the embedded IPv4 address if the IPv6 address
519    comes from 6to4 (RFC 3056) addr space */
520
521 static inline __be32 try_6to4(struct in6_addr *v6dst)
522 {
523         __be32 dst = 0;
524
525         if (v6dst->s6_addr16[0] == htons(0x2002)) {
526                 /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
527                 memcpy(&dst, &v6dst->s6_addr16[1], 4);
528         }
529         return dst;
530 }
531
532 /*
533  *      This function assumes it is being called from dev_queue_xmit()
534  *      and that skb is filled properly by that function.
535  */
536
537 static int ipip6_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
538 {
539         struct ip_tunnel *tunnel = netdev_priv(dev);
540         struct net_device_stats *stats = &tunnel->dev->stats;
541         struct iphdr  *tiph = &tunnel->parms.iph;
542         struct ipv6hdr *iph6 = ipv6_hdr(skb);
543         u8     tos = tunnel->parms.iph.tos;
544         struct rtable *rt;                      /* Route to the other host */
545         struct net_device *tdev;                        /* Device to other host */
546         struct iphdr  *iph;                     /* Our new IP header */
547         unsigned int max_headroom;              /* The extra header space needed */
548         __be32 dst = tiph->daddr;
549         int    mtu;
550         struct in6_addr *addr6;
551         int addr_type;
552
553         if (tunnel->recursion++) {
554                 stats->collisions++;
555                 goto tx_error;
556         }
557
558         if (skb->protocol != htons(ETH_P_IPV6))
559                 goto tx_error;
560
561         /* ISATAP (RFC4214) - must come before 6to4 */
562         if (dev->priv_flags & IFF_ISATAP) {
563                 struct neighbour *neigh = NULL;
564
565                 if (skb->dst)
566                         neigh = skb->dst->neighbour;
567
568                 if (neigh == NULL) {
569                         if (net_ratelimit())
570                                 printk(KERN_DEBUG "sit: nexthop == NULL\n");
571                         goto tx_error;
572                 }
573
574                 addr6 = (struct in6_addr*)&neigh->primary_key;
575                 addr_type = ipv6_addr_type(addr6);
576
577                 if ((addr_type & IPV6_ADDR_UNICAST) &&
578                      ipv6_addr_is_isatap(addr6))
579                         dst = addr6->s6_addr32[3];
580                 else
581                         goto tx_error;
582         }
583
584         if (!dst)
585                 dst = try_6to4(&iph6->daddr);
586
587         if (!dst) {
588                 struct neighbour *neigh = NULL;
589
590                 if (skb->dst)
591                         neigh = skb->dst->neighbour;
592
593                 if (neigh == NULL) {
594                         if (net_ratelimit())
595                                 printk(KERN_DEBUG "sit: nexthop == NULL\n");
596                         goto tx_error;
597                 }
598
599                 addr6 = (struct in6_addr*)&neigh->primary_key;
600                 addr_type = ipv6_addr_type(addr6);
601
602                 if (addr_type == IPV6_ADDR_ANY) {
603                         addr6 = &ipv6_hdr(skb)->daddr;
604                         addr_type = ipv6_addr_type(addr6);
605                 }
606
607                 if ((addr_type & IPV6_ADDR_COMPATv4) == 0)
608                         goto tx_error_icmp;
609
610                 dst = addr6->s6_addr32[3];
611         }
612
613         {
614                 struct flowi fl = { .nl_u = { .ip4_u =
615                                               { .daddr = dst,
616                                                 .saddr = tiph->saddr,
617                                                 .tos = RT_TOS(tos) } },
618                                     .oif = tunnel->parms.link,
619                                     .proto = IPPROTO_IPV6 };
620                 if (ip_route_output_key(dev_net(dev), &rt, &fl)) {
621                         stats->tx_carrier_errors++;
622                         goto tx_error_icmp;
623                 }
624         }
625         if (rt->rt_type != RTN_UNICAST) {
626                 ip_rt_put(rt);
627                 stats->tx_carrier_errors++;
628                 goto tx_error_icmp;
629         }
630         tdev = rt->u.dst.dev;
631
632         if (tdev == dev) {
633                 ip_rt_put(rt);
634                 stats->collisions++;
635                 goto tx_error;
636         }
637
638         if (tiph->frag_off)
639                 mtu = dst_mtu(&rt->u.dst) - sizeof(struct iphdr);
640         else
641                 mtu = skb->dst ? dst_mtu(skb->dst) : dev->mtu;
642
643         if (mtu < 68) {
644                 stats->collisions++;
645                 ip_rt_put(rt);
646                 goto tx_error;
647         }
648         if (mtu < IPV6_MIN_MTU)
649                 mtu = IPV6_MIN_MTU;
650         if (tunnel->parms.iph.daddr && skb->dst)
651                 skb->dst->ops->update_pmtu(skb->dst, mtu);
652
653         if (skb->len > mtu) {
654                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, dev);
655                 ip_rt_put(rt);
656                 goto tx_error;
657         }
658
659         if (tunnel->err_count > 0) {
660                 if (jiffies - tunnel->err_time < IPTUNNEL_ERR_TIMEO) {
661                         tunnel->err_count--;
662                         dst_link_failure(skb);
663                 } else
664                         tunnel->err_count = 0;
665         }
666
667         /*
668          * Okay, now see if we can stuff it in the buffer as-is.
669          */
670         max_headroom = LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr);
671
672         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
673             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
674                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
675                 if (!new_skb) {
676                         ip_rt_put(rt);
677                         stats->tx_dropped++;
678                         dev_kfree_skb(skb);
679                         tunnel->recursion--;
680                         return 0;
681                 }
682                 if (skb->sk)
683                         skb_set_owner_w(new_skb, skb->sk);
684                 dev_kfree_skb(skb);
685                 skb = new_skb;
686                 iph6 = ipv6_hdr(skb);
687         }
688
689         skb->transport_header = skb->network_header;
690         skb_push(skb, sizeof(struct iphdr));
691         skb_reset_network_header(skb);
692         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
693         IPCB(skb)->flags = 0;
694         dst_release(skb->dst);
695         skb->dst = &rt->u.dst;
696
697         /*
698          *      Push down and install the IPIP header.
699          */
700
701         iph                     =       ip_hdr(skb);
702         iph->version            =       4;
703         iph->ihl                =       sizeof(struct iphdr)>>2;
704         if (mtu > IPV6_MIN_MTU)
705                 iph->frag_off   =       htons(IP_DF);
706         else
707                 iph->frag_off   =       0;
708
709         iph->protocol           =       IPPROTO_IPV6;
710         iph->tos                =       INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
711         iph->daddr              =       rt->rt_dst;
712         iph->saddr              =       rt->rt_src;
713
714         if ((iph->ttl = tiph->ttl) == 0)
715                 iph->ttl        =       iph6->hop_limit;
716
717         nf_reset(skb);
718
719         IPTUNNEL_XMIT();
720         tunnel->recursion--;
721         return 0;
722
723 tx_error_icmp:
724         dst_link_failure(skb);
725 tx_error:
726         stats->tx_errors++;
727         dev_kfree_skb(skb);
728         tunnel->recursion--;
729         return 0;
730 }
731
732 static void ipip6_tunnel_bind_dev(struct net_device *dev)
733 {
734         struct net_device *tdev = NULL;
735         struct ip_tunnel *tunnel;
736         struct iphdr *iph;
737
738         tunnel = netdev_priv(dev);
739         iph = &tunnel->parms.iph;
740
741         if (iph->daddr) {
742                 struct flowi fl = { .nl_u = { .ip4_u =
743                                               { .daddr = iph->daddr,
744                                                 .saddr = iph->saddr,
745                                                 .tos = RT_TOS(iph->tos) } },
746                                     .oif = tunnel->parms.link,
747                                     .proto = IPPROTO_IPV6 };
748                 struct rtable *rt;
749                 if (!ip_route_output_key(dev_net(dev), &rt, &fl)) {
750                         tdev = rt->u.dst.dev;
751                         ip_rt_put(rt);
752                 }
753                 dev->flags |= IFF_POINTOPOINT;
754         }
755
756         if (!tdev && tunnel->parms.link)
757                 tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
758
759         if (tdev) {
760                 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
761                 dev->mtu = tdev->mtu - sizeof(struct iphdr);
762                 if (dev->mtu < IPV6_MIN_MTU)
763                         dev->mtu = IPV6_MIN_MTU;
764         }
765         dev->iflink = tunnel->parms.link;
766 }
767
768 static int
769 ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
770 {
771         int err = 0;
772         struct ip_tunnel_parm p;
773         struct ip_tunnel_prl prl;
774         struct ip_tunnel *t;
775         struct net *net = dev_net(dev);
776         struct sit_net *sitn = net_generic(net, sit_net_id);
777
778         switch (cmd) {
779         case SIOCGETTUNNEL:
780                 t = NULL;
781                 if (dev == sitn->fb_tunnel_dev) {
782                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
783                                 err = -EFAULT;
784                                 break;
785                         }
786                         t = ipip6_tunnel_locate(net, &p, 0);
787                 }
788                 if (t == NULL)
789                         t = netdev_priv(dev);
790                 memcpy(&p, &t->parms, sizeof(p));
791                 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
792                         err = -EFAULT;
793                 break;
794
795         case SIOCADDTUNNEL:
796         case SIOCCHGTUNNEL:
797                 err = -EPERM;
798                 if (!capable(CAP_NET_ADMIN))
799                         goto done;
800
801                 err = -EFAULT;
802                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
803                         goto done;
804
805                 err = -EINVAL;
806                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPV6 ||
807                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
808                         goto done;
809                 if (p.iph.ttl)
810                         p.iph.frag_off |= htons(IP_DF);
811
812                 t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
813
814                 if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
815                         if (t != NULL) {
816                                 if (t->dev != dev) {
817                                         err = -EEXIST;
818                                         break;
819                                 }
820                         } else {
821                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
822                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
823                                         err = -EINVAL;
824                                         break;
825                                 }
826                                 t = netdev_priv(dev);
827                                 ipip6_tunnel_unlink(sitn, t);
828                                 t->parms.iph.saddr = p.iph.saddr;
829                                 t->parms.iph.daddr = p.iph.daddr;
830                                 memcpy(dev->dev_addr, &p.iph.saddr, 4);
831                                 memcpy(dev->broadcast, &p.iph.daddr, 4);
832                                 ipip6_tunnel_link(sitn, t);
833                                 netdev_state_change(dev);
834                         }
835                 }
836
837                 if (t) {
838                         err = 0;
839                         if (cmd == SIOCCHGTUNNEL) {
840                                 t->parms.iph.ttl = p.iph.ttl;
841                                 t->parms.iph.tos = p.iph.tos;
842                                 if (t->parms.link != p.link) {
843                                         t->parms.link = p.link;
844                                         ipip6_tunnel_bind_dev(dev);
845                                         netdev_state_change(dev);
846                                 }
847                         }
848                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
849                                 err = -EFAULT;
850                 } else
851                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
852                 break;
853
854         case SIOCDELTUNNEL:
855                 err = -EPERM;
856                 if (!capable(CAP_NET_ADMIN))
857                         goto done;
858
859                 if (dev == sitn->fb_tunnel_dev) {
860                         err = -EFAULT;
861                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
862                                 goto done;
863                         err = -ENOENT;
864                         if ((t = ipip6_tunnel_locate(net, &p, 0)) == NULL)
865                                 goto done;
866                         err = -EPERM;
867                         if (t == netdev_priv(sitn->fb_tunnel_dev))
868                                 goto done;
869                         dev = t->dev;
870                 }
871                 unregister_netdevice(dev);
872                 err = 0;
873                 break;
874
875         case SIOCGETPRL:
876                 err = -EINVAL;
877                 if (dev == sitn->fb_tunnel_dev)
878                         goto done;
879                 err = -ENOENT;
880                 if (!(t = netdev_priv(dev)))
881                         goto done;
882                 err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
883                 break;
884
885         case SIOCADDPRL:
886         case SIOCDELPRL:
887         case SIOCCHGPRL:
888                 err = -EPERM;
889                 if (!capable(CAP_NET_ADMIN))
890                         goto done;
891                 err = -EINVAL;
892                 if (dev == sitn->fb_tunnel_dev)
893                         goto done;
894                 err = -EFAULT;
895                 if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
896                         goto done;
897                 err = -ENOENT;
898                 if (!(t = netdev_priv(dev)))
899                         goto done;
900
901                 switch (cmd) {
902                 case SIOCDELPRL:
903                         err = ipip6_tunnel_del_prl(t, &prl);
904                         break;
905                 case SIOCADDPRL:
906                 case SIOCCHGPRL:
907                         err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
908                         break;
909                 }
910                 netdev_state_change(dev);
911                 break;
912
913         default:
914                 err = -EINVAL;
915         }
916
917 done:
918         return err;
919 }
920
921 static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
922 {
923         if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - sizeof(struct iphdr))
924                 return -EINVAL;
925         dev->mtu = new_mtu;
926         return 0;
927 }
928
929 static void ipip6_tunnel_setup(struct net_device *dev)
930 {
931         dev->uninit             = ipip6_tunnel_uninit;
932         dev->destructor         = free_netdev;
933         dev->hard_start_xmit    = ipip6_tunnel_xmit;
934         dev->do_ioctl           = ipip6_tunnel_ioctl;
935         dev->change_mtu         = ipip6_tunnel_change_mtu;
936
937         dev->type               = ARPHRD_SIT;
938         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
939         dev->mtu                = ETH_DATA_LEN - sizeof(struct iphdr);
940         dev->flags              = IFF_NOARP;
941         dev->iflink             = 0;
942         dev->addr_len           = 4;
943         dev->features           |= NETIF_F_NETNS_LOCAL;
944 }
945
946 static int ipip6_tunnel_init(struct net_device *dev)
947 {
948         struct ip_tunnel *tunnel;
949
950         tunnel = netdev_priv(dev);
951
952         tunnel->dev = dev;
953         strcpy(tunnel->parms.name, dev->name);
954
955         memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
956         memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
957
958         ipip6_tunnel_bind_dev(dev);
959
960         return 0;
961 }
962
963 static int ipip6_fb_tunnel_init(struct net_device *dev)
964 {
965         struct ip_tunnel *tunnel = netdev_priv(dev);
966         struct iphdr *iph = &tunnel->parms.iph;
967         struct net *net = dev_net(dev);
968         struct sit_net *sitn = net_generic(net, sit_net_id);
969
970         tunnel->dev = dev;
971         strcpy(tunnel->parms.name, dev->name);
972
973         iph->version            = 4;
974         iph->protocol           = IPPROTO_IPV6;
975         iph->ihl                = 5;
976         iph->ttl                = 64;
977
978         dev_hold(dev);
979         sitn->tunnels_wc[0]     = tunnel;
980         return 0;
981 }
982
983 static struct xfrm_tunnel sit_handler = {
984         .handler        =       ipip6_rcv,
985         .err_handler    =       ipip6_err,
986         .priority       =       1,
987 };
988
989 static void sit_destroy_tunnels(struct sit_net *sitn)
990 {
991         int prio;
992
993         for (prio = 1; prio < 4; prio++) {
994                 int h;
995                 for (h = 0; h < HASH_SIZE; h++) {
996                         struct ip_tunnel *t;
997                         while ((t = sitn->tunnels[prio][h]) != NULL)
998                                 unregister_netdevice(t->dev);
999                 }
1000         }
1001 }
1002
1003 static int sit_init_net(struct net *net)
1004 {
1005         int err;
1006         struct sit_net *sitn;
1007
1008         err = -ENOMEM;
1009         sitn = kzalloc(sizeof(struct sit_net), GFP_KERNEL);
1010         if (sitn == NULL)
1011                 goto err_alloc;
1012
1013         err = net_assign_generic(net, sit_net_id, sitn);
1014         if (err < 0)
1015                 goto err_assign;
1016
1017         sitn->tunnels[0] = sitn->tunnels_wc;
1018         sitn->tunnels[1] = sitn->tunnels_l;
1019         sitn->tunnels[2] = sitn->tunnels_r;
1020         sitn->tunnels[3] = sitn->tunnels_r_l;
1021
1022         sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1023                                            ipip6_tunnel_setup);
1024         if (!sitn->fb_tunnel_dev) {
1025                 err = -ENOMEM;
1026                 goto err_alloc_dev;
1027         }
1028
1029         sitn->fb_tunnel_dev->init = ipip6_fb_tunnel_init;
1030         dev_net_set(sitn->fb_tunnel_dev, net);
1031
1032         if ((err = register_netdev(sitn->fb_tunnel_dev)))
1033                 goto err_reg_dev;
1034
1035         return 0;
1036
1037 err_reg_dev:
1038         free_netdev(sitn->fb_tunnel_dev);
1039 err_alloc_dev:
1040         /* nothing */
1041 err_assign:
1042         kfree(sitn);
1043 err_alloc:
1044         return err;
1045 }
1046
1047 static void sit_exit_net(struct net *net)
1048 {
1049         struct sit_net *sitn;
1050
1051         sitn = net_generic(net, sit_net_id);
1052         rtnl_lock();
1053         sit_destroy_tunnels(sitn);
1054         unregister_netdevice(sitn->fb_tunnel_dev);
1055         rtnl_unlock();
1056         kfree(sitn);
1057 }
1058
1059 static struct pernet_operations sit_net_ops = {
1060         .init = sit_init_net,
1061         .exit = sit_exit_net,
1062 };
1063
1064 static void __exit sit_cleanup(void)
1065 {
1066         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1067
1068         unregister_pernet_gen_device(sit_net_id, &sit_net_ops);
1069 }
1070
1071 static int __init sit_init(void)
1072 {
1073         int err;
1074
1075         printk(KERN_INFO "IPv6 over IPv4 tunneling driver\n");
1076
1077         if (xfrm4_tunnel_register(&sit_handler, AF_INET6) < 0) {
1078                 printk(KERN_INFO "sit init: Can't add protocol\n");
1079                 return -EAGAIN;
1080         }
1081
1082         err = register_pernet_gen_device(&sit_net_id, &sit_net_ops);
1083         if (err < 0)
1084                 xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1085
1086         return err;
1087 }
1088
1089 module_init(sit_init);
1090 module_exit(sit_cleanup);
1091 MODULE_LICENSE("GPL");
1092 MODULE_ALIAS("sit0");