Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6
[linux-2.6.git] / net / ipv6 / exthdrs.c
1 /*
2  *      Extension Header handling for IPv6
3  *      Linux INET6 implementation
4  *
5  *      Authors:
6  *      Pedro Roque             <roque@di.fc.ul.pt>
7  *      Andi Kleen              <ak@muc.de>
8  *      Alexey Kuznetsov        <kuznet@ms2.inr.ac.ru>
9  *
10  *      This program is free software; you can redistribute it and/or
11  *      modify it under the terms of the GNU General Public License
12  *      as published by the Free Software Foundation; either version
13  *      2 of the License, or (at your option) any later version.
14  */
15
16 /* Changes:
17  *      yoshfuji                : ensure not to overrun while parsing
18  *                                tlv options.
19  *      Mitsuru KANDA @USAGI and: Remove ipv6_parse_exthdrs().
20  *      YOSHIFUJI Hideaki @USAGI  Register inbound extension header
21  *                                handlers as inet6_protocol{}.
22  */
23
24 #include <linux/errno.h>
25 #include <linux/types.h>
26 #include <linux/socket.h>
27 #include <linux/sockios.h>
28 #include <linux/net.h>
29 #include <linux/netdevice.h>
30 #include <linux/in6.h>
31 #include <linux/icmpv6.h>
32
33 #include <net/dst.h>
34 #include <net/sock.h>
35 #include <net/snmp.h>
36
37 #include <net/ipv6.h>
38 #include <net/protocol.h>
39 #include <net/transp_v6.h>
40 #include <net/rawv6.h>
41 #include <net/ndisc.h>
42 #include <net/ip6_route.h>
43 #include <net/addrconf.h>
44 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
45 #include <net/xfrm.h>
46 #endif
47
48 #include <asm/uaccess.h>
49
50 int ipv6_find_tlv(struct sk_buff *skb, int offset, int type)
51 {
52         const unsigned char *nh = skb_network_header(skb);
53         int packet_len = skb->tail - skb->network_header;
54         struct ipv6_opt_hdr *hdr;
55         int len;
56
57         if (offset + 2 > packet_len)
58                 goto bad;
59         hdr = (struct ipv6_opt_hdr *)(nh + offset);
60         len = ((hdr->hdrlen + 1) << 3);
61
62         if (offset + len > packet_len)
63                 goto bad;
64
65         offset += 2;
66         len -= 2;
67
68         while (len > 0) {
69                 int opttype = nh[offset];
70                 int optlen;
71
72                 if (opttype == type)
73                         return offset;
74
75                 switch (opttype) {
76                 case IPV6_TLV_PAD0:
77                         optlen = 1;
78                         break;
79                 default:
80                         optlen = nh[offset + 1] + 2;
81                         if (optlen > len)
82                                 goto bad;
83                         break;
84                 }
85                 offset += optlen;
86                 len -= optlen;
87         }
88         /* not_found */
89  bad:
90         return -1;
91 }
92 EXPORT_SYMBOL_GPL(ipv6_find_tlv);
93
94 /*
95  *      Parsing tlv encoded headers.
96  *
97  *      Parsing function "func" returns 1, if parsing succeed
98  *      and 0, if it failed.
99  *      It MUST NOT touch skb->h.
100  */
101
102 struct tlvtype_proc {
103         int     type;
104         int     (*func)(struct sk_buff *skb, int offset);
105 };
106
107 /*********************
108   Generic functions
109  *********************/
110
111 /* An unknown option is detected, decide what to do */
112
113 static int ip6_tlvopt_unknown(struct sk_buff *skb, int optoff)
114 {
115         switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) {
116         case 0: /* ignore */
117                 return 1;
118
119         case 1: /* drop packet */
120                 break;
121
122         case 3: /* Send ICMP if not a multicast address and drop packet */
123                 /* Actually, it is redundant check. icmp_send
124                    will recheck in any case.
125                  */
126                 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr))
127                         break;
128         case 2: /* send ICMP PARM PROB regardless and drop packet */
129                 icmpv6_param_prob(skb, ICMPV6_UNK_OPTION, optoff);
130                 return 0;
131         }
132
133         kfree_skb(skb);
134         return 0;
135 }
136
137 /* Parse tlv encoded option header (hop-by-hop or destination) */
138
139 static int ip6_parse_tlv(struct tlvtype_proc *procs, struct sk_buff *skb)
140 {
141         struct tlvtype_proc *curr;
142         const unsigned char *nh = skb_network_header(skb);
143         int off = skb_network_header_len(skb);
144         int len = (skb_transport_header(skb)[1] + 1) << 3;
145
146         if (skb_transport_offset(skb) + len > skb_headlen(skb))
147                 goto bad;
148
149         off += 2;
150         len -= 2;
151
152         while (len > 0) {
153                 int optlen = nh[off + 1] + 2;
154
155                 switch (nh[off]) {
156                 case IPV6_TLV_PAD0:
157                         optlen = 1;
158                         break;
159
160                 case IPV6_TLV_PADN:
161                         break;
162
163                 default: /* Other TLV code so scan list */
164                         if (optlen > len)
165                                 goto bad;
166                         for (curr=procs; curr->type >= 0; curr++) {
167                                 if (curr->type == nh[off]) {
168                                         /* type specific length/alignment
169                                            checks will be performed in the
170                                            func(). */
171                                         if (curr->func(skb, off) == 0)
172                                                 return 0;
173                                         break;
174                                 }
175                         }
176                         if (curr->type < 0) {
177                                 if (ip6_tlvopt_unknown(skb, off) == 0)
178                                         return 0;
179                         }
180                         break;
181                 }
182                 off += optlen;
183                 len -= optlen;
184         }
185         if (len == 0)
186                 return 1;
187 bad:
188         kfree_skb(skb);
189         return 0;
190 }
191
192 /*****************************
193   Destination options header.
194  *****************************/
195
196 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
197 static int ipv6_dest_hao(struct sk_buff *skb, int optoff)
198 {
199         struct ipv6_destopt_hao *hao;
200         struct inet6_skb_parm *opt = IP6CB(skb);
201         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
202         struct in6_addr tmp_addr;
203         int ret;
204
205         if (opt->dsthao) {
206                 LIMIT_NETDEBUG(KERN_DEBUG "hao duplicated\n");
207                 goto discard;
208         }
209         opt->dsthao = opt->dst1;
210         opt->dst1 = 0;
211
212         hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff);
213
214         if (hao->length != 16) {
215                 LIMIT_NETDEBUG(
216                         KERN_DEBUG "hao invalid option length = %d\n", hao->length);
217                 goto discard;
218         }
219
220         if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) {
221                 LIMIT_NETDEBUG(
222                         KERN_DEBUG "hao is not an unicast addr: %pI6\n", &hao->addr);
223                 goto discard;
224         }
225
226         ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr,
227                                (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS);
228         if (unlikely(ret < 0))
229                 goto discard;
230
231         if (skb_cloned(skb)) {
232                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
233                         goto discard;
234
235                 /* update all variable using below by copied skbuff */
236                 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) +
237                                                   optoff);
238                 ipv6h = ipv6_hdr(skb);
239         }
240
241         if (skb->ip_summed == CHECKSUM_COMPLETE)
242                 skb->ip_summed = CHECKSUM_NONE;
243
244         ipv6_addr_copy(&tmp_addr, &ipv6h->saddr);
245         ipv6_addr_copy(&ipv6h->saddr, &hao->addr);
246         ipv6_addr_copy(&hao->addr, &tmp_addr);
247
248         if (skb->tstamp.tv64 == 0)
249                 __net_timestamp(skb);
250
251         return 1;
252
253  discard:
254         kfree_skb(skb);
255         return 0;
256 }
257 #endif
258
259 static struct tlvtype_proc tlvprocdestopt_lst[] = {
260 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
261         {
262                 .type   = IPV6_TLV_HAO,
263                 .func   = ipv6_dest_hao,
264         },
265 #endif
266         {-1,                    NULL}
267 };
268
269 static int ipv6_destopt_rcv(struct sk_buff *skb)
270 {
271         struct inet6_skb_parm *opt = IP6CB(skb);
272 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
273         __u16 dstbuf;
274 #endif
275         struct dst_entry *dst;
276
277         if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
278             !pskb_may_pull(skb, (skb_transport_offset(skb) +
279                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
280                 IP6_INC_STATS_BH(dev_net(skb_dst(skb)->dev), ip6_dst_idev(skb_dst(skb)),
281                                  IPSTATS_MIB_INHDRERRORS);
282                 kfree_skb(skb);
283                 return -1;
284         }
285
286         opt->lastopt = opt->dst1 = skb_network_header_len(skb);
287 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
288         dstbuf = opt->dst1;
289 #endif
290
291         dst = dst_clone(skb_dst(skb));
292         if (ip6_parse_tlv(tlvprocdestopt_lst, skb)) {
293                 dst_release(dst);
294                 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
295                 opt = IP6CB(skb);
296 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
297                 opt->nhoff = dstbuf;
298 #else
299                 opt->nhoff = opt->dst1;
300 #endif
301                 return 1;
302         }
303
304         IP6_INC_STATS_BH(dev_net(dst->dev),
305                          ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS);
306         dst_release(dst);
307         return -1;
308 }
309
310 /********************************
311   Routing header.
312  ********************************/
313
314 static int ipv6_rthdr_rcv(struct sk_buff *skb)
315 {
316         struct inet6_skb_parm *opt = IP6CB(skb);
317         struct in6_addr *addr = NULL;
318         struct in6_addr daddr;
319         struct inet6_dev *idev;
320         int n, i;
321         struct ipv6_rt_hdr *hdr;
322         struct rt0_hdr *rthdr;
323         struct net *net = dev_net(skb->dev);
324         int accept_source_route = net->ipv6.devconf_all->accept_source_route;
325
326         idev = in6_dev_get(skb->dev);
327         if (idev) {
328                 if (accept_source_route > idev->cnf.accept_source_route)
329                         accept_source_route = idev->cnf.accept_source_route;
330                 in6_dev_put(idev);
331         }
332
333         if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
334             !pskb_may_pull(skb, (skb_transport_offset(skb) +
335                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
336                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
337                                  IPSTATS_MIB_INHDRERRORS);
338                 kfree_skb(skb);
339                 return -1;
340         }
341
342         hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
343
344         if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
345             skb->pkt_type != PACKET_HOST) {
346                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
347                                  IPSTATS_MIB_INADDRERRORS);
348                 kfree_skb(skb);
349                 return -1;
350         }
351
352 looped_back:
353         if (hdr->segments_left == 0) {
354                 switch (hdr->type) {
355 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
356                 case IPV6_SRCRT_TYPE_2:
357                         /* Silently discard type 2 header unless it was
358                          * processed by own
359                          */
360                         if (!addr) {
361                                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
362                                                  IPSTATS_MIB_INADDRERRORS);
363                                 kfree_skb(skb);
364                                 return -1;
365                         }
366                         break;
367 #endif
368                 default:
369                         break;
370                 }
371
372                 opt->lastopt = opt->srcrt = skb_network_header_len(skb);
373                 skb->transport_header += (hdr->hdrlen + 1) << 3;
374                 opt->dst0 = opt->dst1;
375                 opt->dst1 = 0;
376                 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
377                 return 1;
378         }
379
380         switch (hdr->type) {
381 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
382         case IPV6_SRCRT_TYPE_2:
383                 if (accept_source_route < 0)
384                         goto unknown_rh;
385                 /* Silently discard invalid RTH type 2 */
386                 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
387                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
388                                          IPSTATS_MIB_INHDRERRORS);
389                         kfree_skb(skb);
390                         return -1;
391                 }
392                 break;
393 #endif
394         default:
395                 goto unknown_rh;
396         }
397
398         /*
399          *      This is the routing header forwarding algorithm from
400          *      RFC 2460, page 16.
401          */
402
403         n = hdr->hdrlen >> 1;
404
405         if (hdr->segments_left > n) {
406                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
407                                  IPSTATS_MIB_INHDRERRORS);
408                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
409                                   ((&hdr->segments_left) -
410                                    skb_network_header(skb)));
411                 return -1;
412         }
413
414         /* We are about to mangle packet header. Be careful!
415            Do not damage packets queued somewhere.
416          */
417         if (skb_cloned(skb)) {
418                 /* the copy is a forwarded packet */
419                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
420                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
421                                          IPSTATS_MIB_OUTDISCARDS);
422                         kfree_skb(skb);
423                         return -1;
424                 }
425                 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
426         }
427
428         if (skb->ip_summed == CHECKSUM_COMPLETE)
429                 skb->ip_summed = CHECKSUM_NONE;
430
431         i = n - --hdr->segments_left;
432
433         rthdr = (struct rt0_hdr *) hdr;
434         addr = rthdr->addr;
435         addr += i - 1;
436
437         switch (hdr->type) {
438 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
439         case IPV6_SRCRT_TYPE_2:
440                 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
441                                      (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
442                                      IPPROTO_ROUTING) < 0) {
443                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
444                                          IPSTATS_MIB_INADDRERRORS);
445                         kfree_skb(skb);
446                         return -1;
447                 }
448                 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) {
449                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
450                                          IPSTATS_MIB_INADDRERRORS);
451                         kfree_skb(skb);
452                         return -1;
453                 }
454                 break;
455 #endif
456         default:
457                 break;
458         }
459
460         if (ipv6_addr_is_multicast(addr)) {
461                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
462                                  IPSTATS_MIB_INADDRERRORS);
463                 kfree_skb(skb);
464                 return -1;
465         }
466
467         ipv6_addr_copy(&daddr, addr);
468         ipv6_addr_copy(addr, &ipv6_hdr(skb)->daddr);
469         ipv6_addr_copy(&ipv6_hdr(skb)->daddr, &daddr);
470
471         skb_dst_drop(skb);
472         ip6_route_input(skb);
473         if (skb_dst(skb)->error) {
474                 skb_push(skb, skb->data - skb_network_header(skb));
475                 dst_input(skb);
476                 return -1;
477         }
478
479         if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) {
480                 if (ipv6_hdr(skb)->hop_limit <= 1) {
481                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
482                                          IPSTATS_MIB_INHDRERRORS);
483                         icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
484                                     0);
485                         kfree_skb(skb);
486                         return -1;
487                 }
488                 ipv6_hdr(skb)->hop_limit--;
489                 goto looped_back;
490         }
491
492         skb_push(skb, skb->data - skb_network_header(skb));
493         dst_input(skb);
494         return -1;
495
496 unknown_rh:
497         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INHDRERRORS);
498         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
499                           (&hdr->type) - skb_network_header(skb));
500         return -1;
501 }
502
503 static const struct inet6_protocol rthdr_protocol = {
504         .handler        =       ipv6_rthdr_rcv,
505         .flags          =       INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
506 };
507
508 static const struct inet6_protocol destopt_protocol = {
509         .handler        =       ipv6_destopt_rcv,
510         .flags          =       INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
511 };
512
513 static const struct inet6_protocol nodata_protocol = {
514         .handler        =       dst_discard,
515         .flags          =       INET6_PROTO_NOPOLICY,
516 };
517
518 int __init ipv6_exthdrs_init(void)
519 {
520         int ret;
521
522         ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
523         if (ret)
524                 goto out;
525
526         ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
527         if (ret)
528                 goto out_rthdr;
529
530         ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
531         if (ret)
532                 goto out_destopt;
533
534 out:
535         return ret;
536 out_rthdr:
537         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
538 out_destopt:
539         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
540         goto out;
541 };
542
543 void ipv6_exthdrs_exit(void)
544 {
545         inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
546         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
547         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
548 }
549
550 /**********************************
551   Hop-by-hop options.
552  **********************************/
553
554 /*
555  * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input().
556  */
557 static inline struct inet6_dev *ipv6_skb_idev(struct sk_buff *skb)
558 {
559         return skb_dst(skb) ? ip6_dst_idev(skb_dst(skb)) : __in6_dev_get(skb->dev);
560 }
561
562 static inline struct net *ipv6_skb_net(struct sk_buff *skb)
563 {
564         return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev);
565 }
566
567 /* Router Alert as of RFC 2711 */
568
569 static int ipv6_hop_ra(struct sk_buff *skb, int optoff)
570 {
571         const unsigned char *nh = skb_network_header(skb);
572
573         if (nh[optoff + 1] == 2) {
574                 IP6CB(skb)->ra = optoff;
575                 return 1;
576         }
577         LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_ra: wrong RA length %d\n",
578                        nh[optoff + 1]);
579         kfree_skb(skb);
580         return 0;
581 }
582
583 /* Jumbo payload */
584
585 static int ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
586 {
587         const unsigned char *nh = skb_network_header(skb);
588         struct net *net = ipv6_skb_net(skb);
589         u32 pkt_len;
590
591         if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
592                 LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
593                                nh[optoff+1]);
594                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
595                                  IPSTATS_MIB_INHDRERRORS);
596                 goto drop;
597         }
598
599         pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
600         if (pkt_len <= IPV6_MAXPLEN) {
601                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
602                                  IPSTATS_MIB_INHDRERRORS);
603                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
604                 return 0;
605         }
606         if (ipv6_hdr(skb)->payload_len) {
607                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
608                                  IPSTATS_MIB_INHDRERRORS);
609                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
610                 return 0;
611         }
612
613         if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
614                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
615                                  IPSTATS_MIB_INTRUNCATEDPKTS);
616                 goto drop;
617         }
618
619         if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
620                 goto drop;
621
622         return 1;
623
624 drop:
625         kfree_skb(skb);
626         return 0;
627 }
628
629 static struct tlvtype_proc tlvprochopopt_lst[] = {
630         {
631                 .type   = IPV6_TLV_ROUTERALERT,
632                 .func   = ipv6_hop_ra,
633         },
634         {
635                 .type   = IPV6_TLV_JUMBO,
636                 .func   = ipv6_hop_jumbo,
637         },
638         { -1, }
639 };
640
641 int ipv6_parse_hopopts(struct sk_buff *skb)
642 {
643         struct inet6_skb_parm *opt = IP6CB(skb);
644
645         /*
646          * skb_network_header(skb) is equal to skb->data, and
647          * skb_network_header_len(skb) is always equal to
648          * sizeof(struct ipv6hdr) by definition of
649          * hop-by-hop options.
650          */
651         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
652             !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
653                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
654                 kfree_skb(skb);
655                 return -1;
656         }
657
658         opt->hop = sizeof(struct ipv6hdr);
659         if (ip6_parse_tlv(tlvprochopopt_lst, skb)) {
660                 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
661                 opt = IP6CB(skb);
662                 opt->nhoff = sizeof(struct ipv6hdr);
663                 return 1;
664         }
665         return -1;
666 }
667
668 /*
669  *      Creating outbound headers.
670  *
671  *      "build" functions work when skb is filled from head to tail (datagram)
672  *      "push"  functions work when headers are added from tail to head (tcp)
673  *
674  *      In both cases we assume, that caller reserved enough room
675  *      for headers.
676  */
677
678 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
679                             struct ipv6_rt_hdr *opt,
680                             struct in6_addr **addr_p)
681 {
682         struct rt0_hdr *phdr, *ihdr;
683         int hops;
684
685         ihdr = (struct rt0_hdr *) opt;
686
687         phdr = (struct rt0_hdr *) skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
688         memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
689
690         hops = ihdr->rt_hdr.hdrlen >> 1;
691
692         if (hops > 1)
693                 memcpy(phdr->addr, ihdr->addr + 1,
694                        (hops - 1) * sizeof(struct in6_addr));
695
696         ipv6_addr_copy(phdr->addr + (hops - 1), *addr_p);
697         *addr_p = ihdr->addr;
698
699         phdr->rt_hdr.nexthdr = *proto;
700         *proto = NEXTHDR_ROUTING;
701 }
702
703 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
704 {
705         struct ipv6_opt_hdr *h = (struct ipv6_opt_hdr *)skb_push(skb, ipv6_optlen(opt));
706
707         memcpy(h, opt, ipv6_optlen(opt));
708         h->nexthdr = *proto;
709         *proto = type;
710 }
711
712 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
713                           u8 *proto,
714                           struct in6_addr **daddr)
715 {
716         if (opt->srcrt) {
717                 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr);
718                 /*
719                  * IPV6_RTHDRDSTOPTS is ignored
720                  * unless IPV6_RTHDR is set (RFC3542).
721                  */
722                 if (opt->dst0opt)
723                         ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
724         }
725         if (opt->hopopt)
726                 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
727 }
728
729 EXPORT_SYMBOL(ipv6_push_nfrag_opts);
730
731 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
732 {
733         if (opt->dst1opt)
734                 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
735 }
736
737 struct ipv6_txoptions *
738 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
739 {
740         struct ipv6_txoptions *opt2;
741
742         opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
743         if (opt2) {
744                 long dif = (char*)opt2 - (char*)opt;
745                 memcpy(opt2, opt, opt->tot_len);
746                 if (opt2->hopopt)
747                         *((char**)&opt2->hopopt) += dif;
748                 if (opt2->dst0opt)
749                         *((char**)&opt2->dst0opt) += dif;
750                 if (opt2->dst1opt)
751                         *((char**)&opt2->dst1opt) += dif;
752                 if (opt2->srcrt)
753                         *((char**)&opt2->srcrt) += dif;
754         }
755         return opt2;
756 }
757
758 EXPORT_SYMBOL_GPL(ipv6_dup_options);
759
760 static int ipv6_renew_option(void *ohdr,
761                              struct ipv6_opt_hdr __user *newopt, int newoptlen,
762                              int inherit,
763                              struct ipv6_opt_hdr **hdr,
764                              char **p)
765 {
766         if (inherit) {
767                 if (ohdr) {
768                         memcpy(*p, ohdr, ipv6_optlen((struct ipv6_opt_hdr *)ohdr));
769                         *hdr = (struct ipv6_opt_hdr *)*p;
770                         *p += CMSG_ALIGN(ipv6_optlen(*(struct ipv6_opt_hdr **)hdr));
771                 }
772         } else {
773                 if (newopt) {
774                         if (copy_from_user(*p, newopt, newoptlen))
775                                 return -EFAULT;
776                         *hdr = (struct ipv6_opt_hdr *)*p;
777                         if (ipv6_optlen(*(struct ipv6_opt_hdr **)hdr) > newoptlen)
778                                 return -EINVAL;
779                         *p += CMSG_ALIGN(newoptlen);
780                 }
781         }
782         return 0;
783 }
784
785 struct ipv6_txoptions *
786 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
787                    int newtype,
788                    struct ipv6_opt_hdr __user *newopt, int newoptlen)
789 {
790         int tot_len = 0;
791         char *p;
792         struct ipv6_txoptions *opt2;
793         int err;
794
795         if (opt) {
796                 if (newtype != IPV6_HOPOPTS && opt->hopopt)
797                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
798                 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
799                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
800                 if (newtype != IPV6_RTHDR && opt->srcrt)
801                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
802                 if (newtype != IPV6_DSTOPTS && opt->dst1opt)
803                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
804         }
805
806         if (newopt && newoptlen)
807                 tot_len += CMSG_ALIGN(newoptlen);
808
809         if (!tot_len)
810                 return NULL;
811
812         tot_len += sizeof(*opt2);
813         opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
814         if (!opt2)
815                 return ERR_PTR(-ENOBUFS);
816
817         memset(opt2, 0, tot_len);
818
819         opt2->tot_len = tot_len;
820         p = (char *)(opt2 + 1);
821
822         err = ipv6_renew_option(opt ? opt->hopopt : NULL, newopt, newoptlen,
823                                 newtype != IPV6_HOPOPTS,
824                                 &opt2->hopopt, &p);
825         if (err)
826                 goto out;
827
828         err = ipv6_renew_option(opt ? opt->dst0opt : NULL, newopt, newoptlen,
829                                 newtype != IPV6_RTHDRDSTOPTS,
830                                 &opt2->dst0opt, &p);
831         if (err)
832                 goto out;
833
834         err = ipv6_renew_option(opt ? opt->srcrt : NULL, newopt, newoptlen,
835                                 newtype != IPV6_RTHDR,
836                                 (struct ipv6_opt_hdr **)&opt2->srcrt, &p);
837         if (err)
838                 goto out;
839
840         err = ipv6_renew_option(opt ? opt->dst1opt : NULL, newopt, newoptlen,
841                                 newtype != IPV6_DSTOPTS,
842                                 &opt2->dst1opt, &p);
843         if (err)
844                 goto out;
845
846         opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
847                           (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
848                           (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
849         opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
850
851         return opt2;
852 out:
853         sock_kfree_s(sk, opt2, opt2->tot_len);
854         return ERR_PTR(err);
855 }
856
857 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
858                                           struct ipv6_txoptions *opt)
859 {
860         /*
861          * ignore the dest before srcrt unless srcrt is being included.
862          * --yoshfuji
863          */
864         if (opt && opt->dst0opt && !opt->srcrt) {
865                 if (opt_space != opt) {
866                         memcpy(opt_space, opt, sizeof(*opt_space));
867                         opt = opt_space;
868                 }
869                 opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
870                 opt->dst0opt = NULL;
871         }
872
873         return opt;
874 }
875