Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wirel...
[pandora-kernel.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 #include <linux/slab.h>
33 #include <linux/export.h>
34
35 #include <net/dst.h>
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/rawv6.h>
43 #include <net/ndisc.h>
44 #include <net/ip6_route.h>
45 #include <net/addrconf.h>
46 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
47 #include <net/xfrm.h>
48 #endif
49
50 #include <asm/uaccess.h>
51
52 int ipv6_find_tlv(struct sk_buff *skb, int offset, int type)
53 {
54         const unsigned char *nh = skb_network_header(skb);
55         int packet_len = skb->tail - skb->network_header;
56         struct ipv6_opt_hdr *hdr;
57         int len;
58
59         if (offset + 2 > packet_len)
60                 goto bad;
61         hdr = (struct ipv6_opt_hdr *)(nh + offset);
62         len = ((hdr->hdrlen + 1) << 3);
63
64         if (offset + len > packet_len)
65                 goto bad;
66
67         offset += 2;
68         len -= 2;
69
70         while (len > 0) {
71                 int opttype = nh[offset];
72                 int optlen;
73
74                 if (opttype == type)
75                         return offset;
76
77                 switch (opttype) {
78                 case IPV6_TLV_PAD0:
79                         optlen = 1;
80                         break;
81                 default:
82                         optlen = nh[offset + 1] + 2;
83                         if (optlen > len)
84                                 goto bad;
85                         break;
86                 }
87                 offset += optlen;
88                 len -= optlen;
89         }
90         /* not_found */
91  bad:
92         return -1;
93 }
94 EXPORT_SYMBOL_GPL(ipv6_find_tlv);
95
96 /*
97  *      Parsing tlv encoded headers.
98  *
99  *      Parsing function "func" returns 1, if parsing succeed
100  *      and 0, if it failed.
101  *      It MUST NOT touch skb->h.
102  */
103
104 struct tlvtype_proc {
105         int     type;
106         int     (*func)(struct sk_buff *skb, int offset);
107 };
108
109 /*********************
110   Generic functions
111  *********************/
112
113 /* An unknown option is detected, decide what to do */
114
115 static int ip6_tlvopt_unknown(struct sk_buff *skb, int optoff)
116 {
117         switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) {
118         case 0: /* ignore */
119                 return 1;
120
121         case 1: /* drop packet */
122                 break;
123
124         case 3: /* Send ICMP if not a multicast address and drop packet */
125                 /* Actually, it is redundant check. icmp_send
126                    will recheck in any case.
127                  */
128                 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr))
129                         break;
130         case 2: /* send ICMP PARM PROB regardless and drop packet */
131                 icmpv6_param_prob(skb, ICMPV6_UNK_OPTION, optoff);
132                 return 0;
133         }
134
135         kfree_skb(skb);
136         return 0;
137 }
138
139 /* Parse tlv encoded option header (hop-by-hop or destination) */
140
141 static int ip6_parse_tlv(struct tlvtype_proc *procs, struct sk_buff *skb)
142 {
143         struct tlvtype_proc *curr;
144         const unsigned char *nh = skb_network_header(skb);
145         int off = skb_network_header_len(skb);
146         int len = (skb_transport_header(skb)[1] + 1) << 3;
147
148         if (skb_transport_offset(skb) + len > skb_headlen(skb))
149                 goto bad;
150
151         off += 2;
152         len -= 2;
153
154         while (len > 0) {
155                 int optlen = nh[off + 1] + 2;
156
157                 switch (nh[off]) {
158                 case IPV6_TLV_PAD0:
159                         optlen = 1;
160                         break;
161
162                 case IPV6_TLV_PADN:
163                         break;
164
165                 default: /* Other TLV code so scan list */
166                         if (optlen > len)
167                                 goto bad;
168                         for (curr=procs; curr->type >= 0; curr++) {
169                                 if (curr->type == nh[off]) {
170                                         /* type specific length/alignment
171                                            checks will be performed in the
172                                            func(). */
173                                         if (curr->func(skb, off) == 0)
174                                                 return 0;
175                                         break;
176                                 }
177                         }
178                         if (curr->type < 0) {
179                                 if (ip6_tlvopt_unknown(skb, off) == 0)
180                                         return 0;
181                         }
182                         break;
183                 }
184                 off += optlen;
185                 len -= optlen;
186         }
187         if (len == 0)
188                 return 1;
189 bad:
190         kfree_skb(skb);
191         return 0;
192 }
193
194 /*****************************
195   Destination options header.
196  *****************************/
197
198 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
199 static int ipv6_dest_hao(struct sk_buff *skb, int optoff)
200 {
201         struct ipv6_destopt_hao *hao;
202         struct inet6_skb_parm *opt = IP6CB(skb);
203         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
204         struct in6_addr tmp_addr;
205         int ret;
206
207         if (opt->dsthao) {
208                 LIMIT_NETDEBUG(KERN_DEBUG "hao duplicated\n");
209                 goto discard;
210         }
211         opt->dsthao = opt->dst1;
212         opt->dst1 = 0;
213
214         hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff);
215
216         if (hao->length != 16) {
217                 LIMIT_NETDEBUG(
218                         KERN_DEBUG "hao invalid option length = %d\n", hao->length);
219                 goto discard;
220         }
221
222         if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) {
223                 LIMIT_NETDEBUG(
224                         KERN_DEBUG "hao is not an unicast addr: %pI6\n", &hao->addr);
225                 goto discard;
226         }
227
228         ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr,
229                                (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS);
230         if (unlikely(ret < 0))
231                 goto discard;
232
233         if (skb_cloned(skb)) {
234                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
235                         goto discard;
236
237                 /* update all variable using below by copied skbuff */
238                 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) +
239                                                   optoff);
240                 ipv6h = ipv6_hdr(skb);
241         }
242
243         if (skb->ip_summed == CHECKSUM_COMPLETE)
244                 skb->ip_summed = CHECKSUM_NONE;
245
246         ipv6_addr_copy(&tmp_addr, &ipv6h->saddr);
247         ipv6_addr_copy(&ipv6h->saddr, &hao->addr);
248         ipv6_addr_copy(&hao->addr, &tmp_addr);
249
250         if (skb->tstamp.tv64 == 0)
251                 __net_timestamp(skb);
252
253         return 1;
254
255  discard:
256         kfree_skb(skb);
257         return 0;
258 }
259 #endif
260
261 static struct tlvtype_proc tlvprocdestopt_lst[] = {
262 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
263         {
264                 .type   = IPV6_TLV_HAO,
265                 .func   = ipv6_dest_hao,
266         },
267 #endif
268         {-1,                    NULL}
269 };
270
271 static int ipv6_destopt_rcv(struct sk_buff *skb)
272 {
273         struct inet6_skb_parm *opt = IP6CB(skb);
274 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
275         __u16 dstbuf;
276 #endif
277         struct dst_entry *dst = skb_dst(skb);
278
279         if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
280             !pskb_may_pull(skb, (skb_transport_offset(skb) +
281                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
282                 IP6_INC_STATS_BH(dev_net(dst->dev), ip6_dst_idev(dst),
283                                  IPSTATS_MIB_INHDRERRORS);
284                 kfree_skb(skb);
285                 return -1;
286         }
287
288         opt->lastopt = opt->dst1 = skb_network_header_len(skb);
289 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
290         dstbuf = opt->dst1;
291 #endif
292
293         if (ip6_parse_tlv(tlvprocdestopt_lst, skb)) {
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         return -1;
307 }
308
309 /********************************
310   Routing header.
311  ********************************/
312
313 /* called with rcu_read_lock() */
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 && accept_source_route > idev->cnf.accept_source_route)
328                 accept_source_route = idev->cnf.accept_source_route;
329
330         if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
331             !pskb_may_pull(skb, (skb_transport_offset(skb) +
332                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
333                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
334                                  IPSTATS_MIB_INHDRERRORS);
335                 kfree_skb(skb);
336                 return -1;
337         }
338
339         hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
340
341         if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
342             skb->pkt_type != PACKET_HOST) {
343                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
344                                  IPSTATS_MIB_INADDRERRORS);
345                 kfree_skb(skb);
346                 return -1;
347         }
348
349 looped_back:
350         if (hdr->segments_left == 0) {
351                 switch (hdr->type) {
352 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
353                 case IPV6_SRCRT_TYPE_2:
354                         /* Silently discard type 2 header unless it was
355                          * processed by own
356                          */
357                         if (!addr) {
358                                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
359                                                  IPSTATS_MIB_INADDRERRORS);
360                                 kfree_skb(skb);
361                                 return -1;
362                         }
363                         break;
364 #endif
365                 default:
366                         break;
367                 }
368
369                 opt->lastopt = opt->srcrt = skb_network_header_len(skb);
370                 skb->transport_header += (hdr->hdrlen + 1) << 3;
371                 opt->dst0 = opt->dst1;
372                 opt->dst1 = 0;
373                 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
374                 return 1;
375         }
376
377         switch (hdr->type) {
378 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
379         case IPV6_SRCRT_TYPE_2:
380                 if (accept_source_route < 0)
381                         goto unknown_rh;
382                 /* Silently discard invalid RTH type 2 */
383                 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
384                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
385                                          IPSTATS_MIB_INHDRERRORS);
386                         kfree_skb(skb);
387                         return -1;
388                 }
389                 break;
390 #endif
391         default:
392                 goto unknown_rh;
393         }
394
395         /*
396          *      This is the routing header forwarding algorithm from
397          *      RFC 2460, page 16.
398          */
399
400         n = hdr->hdrlen >> 1;
401
402         if (hdr->segments_left > n) {
403                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
404                                  IPSTATS_MIB_INHDRERRORS);
405                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
406                                   ((&hdr->segments_left) -
407                                    skb_network_header(skb)));
408                 return -1;
409         }
410
411         /* We are about to mangle packet header. Be careful!
412            Do not damage packets queued somewhere.
413          */
414         if (skb_cloned(skb)) {
415                 /* the copy is a forwarded packet */
416                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
417                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
418                                          IPSTATS_MIB_OUTDISCARDS);
419                         kfree_skb(skb);
420                         return -1;
421                 }
422                 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
423         }
424
425         if (skb->ip_summed == CHECKSUM_COMPLETE)
426                 skb->ip_summed = CHECKSUM_NONE;
427
428         i = n - --hdr->segments_left;
429
430         rthdr = (struct rt0_hdr *) hdr;
431         addr = rthdr->addr;
432         addr += i - 1;
433
434         switch (hdr->type) {
435 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
436         case IPV6_SRCRT_TYPE_2:
437                 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
438                                      (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
439                                      IPPROTO_ROUTING) < 0) {
440                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
441                                          IPSTATS_MIB_INADDRERRORS);
442                         kfree_skb(skb);
443                         return -1;
444                 }
445                 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) {
446                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
447                                          IPSTATS_MIB_INADDRERRORS);
448                         kfree_skb(skb);
449                         return -1;
450                 }
451                 break;
452 #endif
453         default:
454                 break;
455         }
456
457         if (ipv6_addr_is_multicast(addr)) {
458                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
459                                  IPSTATS_MIB_INADDRERRORS);
460                 kfree_skb(skb);
461                 return -1;
462         }
463
464         ipv6_addr_copy(&daddr, addr);
465         ipv6_addr_copy(addr, &ipv6_hdr(skb)->daddr);
466         ipv6_addr_copy(&ipv6_hdr(skb)->daddr, &daddr);
467
468         skb_dst_drop(skb);
469         ip6_route_input(skb);
470         if (skb_dst(skb)->error) {
471                 skb_push(skb, skb->data - skb_network_header(skb));
472                 dst_input(skb);
473                 return -1;
474         }
475
476         if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) {
477                 if (ipv6_hdr(skb)->hop_limit <= 1) {
478                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
479                                          IPSTATS_MIB_INHDRERRORS);
480                         icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
481                                     0);
482                         kfree_skb(skb);
483                         return -1;
484                 }
485                 ipv6_hdr(skb)->hop_limit--;
486                 goto looped_back;
487         }
488
489         skb_push(skb, skb->data - skb_network_header(skb));
490         dst_input(skb);
491         return -1;
492
493 unknown_rh:
494         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INHDRERRORS);
495         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
496                           (&hdr->type) - skb_network_header(skb));
497         return -1;
498 }
499
500 static const struct inet6_protocol rthdr_protocol = {
501         .handler        =       ipv6_rthdr_rcv,
502         .flags          =       INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
503 };
504
505 static const struct inet6_protocol destopt_protocol = {
506         .handler        =       ipv6_destopt_rcv,
507         .flags          =       INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
508 };
509
510 static const struct inet6_protocol nodata_protocol = {
511         .handler        =       dst_discard,
512         .flags          =       INET6_PROTO_NOPOLICY,
513 };
514
515 int __init ipv6_exthdrs_init(void)
516 {
517         int ret;
518
519         ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
520         if (ret)
521                 goto out;
522
523         ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
524         if (ret)
525                 goto out_rthdr;
526
527         ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
528         if (ret)
529                 goto out_destopt;
530
531 out:
532         return ret;
533 out_rthdr:
534         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
535 out_destopt:
536         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
537         goto out;
538 };
539
540 void ipv6_exthdrs_exit(void)
541 {
542         inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
543         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
544         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
545 }
546
547 /**********************************
548   Hop-by-hop options.
549  **********************************/
550
551 /*
552  * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input().
553  */
554 static inline struct inet6_dev *ipv6_skb_idev(struct sk_buff *skb)
555 {
556         return skb_dst(skb) ? ip6_dst_idev(skb_dst(skb)) : __in6_dev_get(skb->dev);
557 }
558
559 static inline struct net *ipv6_skb_net(struct sk_buff *skb)
560 {
561         return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev);
562 }
563
564 /* Router Alert as of RFC 2711 */
565
566 static int ipv6_hop_ra(struct sk_buff *skb, int optoff)
567 {
568         const unsigned char *nh = skb_network_header(skb);
569
570         if (nh[optoff + 1] == 2) {
571                 IP6CB(skb)->ra = optoff;
572                 return 1;
573         }
574         LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_ra: wrong RA length %d\n",
575                        nh[optoff + 1]);
576         kfree_skb(skb);
577         return 0;
578 }
579
580 /* Jumbo payload */
581
582 static int ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
583 {
584         const unsigned char *nh = skb_network_header(skb);
585         struct net *net = ipv6_skb_net(skb);
586         u32 pkt_len;
587
588         if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
589                 LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
590                                nh[optoff+1]);
591                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
592                                  IPSTATS_MIB_INHDRERRORS);
593                 goto drop;
594         }
595
596         pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
597         if (pkt_len <= IPV6_MAXPLEN) {
598                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
599                                  IPSTATS_MIB_INHDRERRORS);
600                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
601                 return 0;
602         }
603         if (ipv6_hdr(skb)->payload_len) {
604                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
605                                  IPSTATS_MIB_INHDRERRORS);
606                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
607                 return 0;
608         }
609
610         if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
611                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
612                                  IPSTATS_MIB_INTRUNCATEDPKTS);
613                 goto drop;
614         }
615
616         if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
617                 goto drop;
618
619         return 1;
620
621 drop:
622         kfree_skb(skb);
623         return 0;
624 }
625
626 static struct tlvtype_proc tlvprochopopt_lst[] = {
627         {
628                 .type   = IPV6_TLV_ROUTERALERT,
629                 .func   = ipv6_hop_ra,
630         },
631         {
632                 .type   = IPV6_TLV_JUMBO,
633                 .func   = ipv6_hop_jumbo,
634         },
635         { -1, }
636 };
637
638 int ipv6_parse_hopopts(struct sk_buff *skb)
639 {
640         struct inet6_skb_parm *opt = IP6CB(skb);
641
642         /*
643          * skb_network_header(skb) is equal to skb->data, and
644          * skb_network_header_len(skb) is always equal to
645          * sizeof(struct ipv6hdr) by definition of
646          * hop-by-hop options.
647          */
648         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
649             !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
650                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
651                 kfree_skb(skb);
652                 return -1;
653         }
654
655         opt->hop = sizeof(struct ipv6hdr);
656         if (ip6_parse_tlv(tlvprochopopt_lst, skb)) {
657                 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
658                 opt = IP6CB(skb);
659                 opt->nhoff = sizeof(struct ipv6hdr);
660                 return 1;
661         }
662         return -1;
663 }
664
665 /*
666  *      Creating outbound headers.
667  *
668  *      "build" functions work when skb is filled from head to tail (datagram)
669  *      "push"  functions work when headers are added from tail to head (tcp)
670  *
671  *      In both cases we assume, that caller reserved enough room
672  *      for headers.
673  */
674
675 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
676                             struct ipv6_rt_hdr *opt,
677                             struct in6_addr **addr_p)
678 {
679         struct rt0_hdr *phdr, *ihdr;
680         int hops;
681
682         ihdr = (struct rt0_hdr *) opt;
683
684         phdr = (struct rt0_hdr *) skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
685         memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
686
687         hops = ihdr->rt_hdr.hdrlen >> 1;
688
689         if (hops > 1)
690                 memcpy(phdr->addr, ihdr->addr + 1,
691                        (hops - 1) * sizeof(struct in6_addr));
692
693         ipv6_addr_copy(phdr->addr + (hops - 1), *addr_p);
694         *addr_p = ihdr->addr;
695
696         phdr->rt_hdr.nexthdr = *proto;
697         *proto = NEXTHDR_ROUTING;
698 }
699
700 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
701 {
702         struct ipv6_opt_hdr *h = (struct ipv6_opt_hdr *)skb_push(skb, ipv6_optlen(opt));
703
704         memcpy(h, opt, ipv6_optlen(opt));
705         h->nexthdr = *proto;
706         *proto = type;
707 }
708
709 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
710                           u8 *proto,
711                           struct in6_addr **daddr)
712 {
713         if (opt->srcrt) {
714                 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr);
715                 /*
716                  * IPV6_RTHDRDSTOPTS is ignored
717                  * unless IPV6_RTHDR is set (RFC3542).
718                  */
719                 if (opt->dst0opt)
720                         ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
721         }
722         if (opt->hopopt)
723                 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
724 }
725
726 EXPORT_SYMBOL(ipv6_push_nfrag_opts);
727
728 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
729 {
730         if (opt->dst1opt)
731                 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
732 }
733
734 struct ipv6_txoptions *
735 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
736 {
737         struct ipv6_txoptions *opt2;
738
739         opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
740         if (opt2) {
741                 long dif = (char*)opt2 - (char*)opt;
742                 memcpy(opt2, opt, opt->tot_len);
743                 if (opt2->hopopt)
744                         *((char**)&opt2->hopopt) += dif;
745                 if (opt2->dst0opt)
746                         *((char**)&opt2->dst0opt) += dif;
747                 if (opt2->dst1opt)
748                         *((char**)&opt2->dst1opt) += dif;
749                 if (opt2->srcrt)
750                         *((char**)&opt2->srcrt) += dif;
751         }
752         return opt2;
753 }
754
755 EXPORT_SYMBOL_GPL(ipv6_dup_options);
756
757 static int ipv6_renew_option(void *ohdr,
758                              struct ipv6_opt_hdr __user *newopt, int newoptlen,
759                              int inherit,
760                              struct ipv6_opt_hdr **hdr,
761                              char **p)
762 {
763         if (inherit) {
764                 if (ohdr) {
765                         memcpy(*p, ohdr, ipv6_optlen((struct ipv6_opt_hdr *)ohdr));
766                         *hdr = (struct ipv6_opt_hdr *)*p;
767                         *p += CMSG_ALIGN(ipv6_optlen(*(struct ipv6_opt_hdr **)hdr));
768                 }
769         } else {
770                 if (newopt) {
771                         if (copy_from_user(*p, newopt, newoptlen))
772                                 return -EFAULT;
773                         *hdr = (struct ipv6_opt_hdr *)*p;
774                         if (ipv6_optlen(*(struct ipv6_opt_hdr **)hdr) > newoptlen)
775                                 return -EINVAL;
776                         *p += CMSG_ALIGN(newoptlen);
777                 }
778         }
779         return 0;
780 }
781
782 struct ipv6_txoptions *
783 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
784                    int newtype,
785                    struct ipv6_opt_hdr __user *newopt, int newoptlen)
786 {
787         int tot_len = 0;
788         char *p;
789         struct ipv6_txoptions *opt2;
790         int err;
791
792         if (opt) {
793                 if (newtype != IPV6_HOPOPTS && opt->hopopt)
794                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
795                 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
796                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
797                 if (newtype != IPV6_RTHDR && opt->srcrt)
798                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
799                 if (newtype != IPV6_DSTOPTS && opt->dst1opt)
800                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
801         }
802
803         if (newopt && newoptlen)
804                 tot_len += CMSG_ALIGN(newoptlen);
805
806         if (!tot_len)
807                 return NULL;
808
809         tot_len += sizeof(*opt2);
810         opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
811         if (!opt2)
812                 return ERR_PTR(-ENOBUFS);
813
814         memset(opt2, 0, tot_len);
815
816         opt2->tot_len = tot_len;
817         p = (char *)(opt2 + 1);
818
819         err = ipv6_renew_option(opt ? opt->hopopt : NULL, newopt, newoptlen,
820                                 newtype != IPV6_HOPOPTS,
821                                 &opt2->hopopt, &p);
822         if (err)
823                 goto out;
824
825         err = ipv6_renew_option(opt ? opt->dst0opt : NULL, newopt, newoptlen,
826                                 newtype != IPV6_RTHDRDSTOPTS,
827                                 &opt2->dst0opt, &p);
828         if (err)
829                 goto out;
830
831         err = ipv6_renew_option(opt ? opt->srcrt : NULL, newopt, newoptlen,
832                                 newtype != IPV6_RTHDR,
833                                 (struct ipv6_opt_hdr **)&opt2->srcrt, &p);
834         if (err)
835                 goto out;
836
837         err = ipv6_renew_option(opt ? opt->dst1opt : NULL, newopt, newoptlen,
838                                 newtype != IPV6_DSTOPTS,
839                                 &opt2->dst1opt, &p);
840         if (err)
841                 goto out;
842
843         opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
844                           (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
845                           (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
846         opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
847
848         return opt2;
849 out:
850         sock_kfree_s(sk, opt2, opt2->tot_len);
851         return ERR_PTR(err);
852 }
853
854 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
855                                           struct ipv6_txoptions *opt)
856 {
857         /*
858          * ignore the dest before srcrt unless srcrt is being included.
859          * --yoshfuji
860          */
861         if (opt && opt->dst0opt && !opt->srcrt) {
862                 if (opt_space != opt) {
863                         memcpy(opt_space, opt, sizeof(*opt_space));
864                         opt = opt_space;
865                 }
866                 opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
867                 opt->dst0opt = NULL;
868         }
869
870         return opt;
871 }
872
873 /**
874  * fl6_update_dst - update flowi destination address with info given
875  *                  by srcrt option, if any.
876  *
877  * @fl6: flowi6 for which daddr is to be updated
878  * @opt: struct ipv6_txoptions in which to look for srcrt opt
879  * @orig: copy of original daddr address if modified
880  *
881  * Returns NULL if no txoptions or no srcrt, otherwise returns orig
882  * and initial value of fl6->daddr set in orig
883  */
884 struct in6_addr *fl6_update_dst(struct flowi6 *fl6,
885                                 const struct ipv6_txoptions *opt,
886                                 struct in6_addr *orig)
887 {
888         if (!opt || !opt->srcrt)
889                 return NULL;
890
891         ipv6_addr_copy(orig, &fl6->daddr);
892         ipv6_addr_copy(&fl6->daddr, ((struct rt0_hdr *)opt->srcrt)->addr);
893         return orig;
894 }
895
896 EXPORT_SYMBOL_GPL(fl6_update_dst);