Merge branch 'next' of git://git.infradead.org/users/vkoul/slave-dma
[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
34 #include <net/dst.h>
35 #include <net/sock.h>
36 #include <net/snmp.h>
37
38 #include <net/ipv6.h>
39 #include <net/protocol.h>
40 #include <net/transp_v6.h>
41 #include <net/rawv6.h>
42 #include <net/ndisc.h>
43 #include <net/ip6_route.h>
44 #include <net/addrconf.h>
45 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
46 #include <net/xfrm.h>
47 #endif
48
49 #include <asm/uaccess.h>
50
51 int ipv6_find_tlv(struct sk_buff *skb, int offset, int type)
52 {
53         const unsigned char *nh = skb_network_header(skb);
54         int packet_len = skb->tail - skb->network_header;
55         struct ipv6_opt_hdr *hdr;
56         int len;
57
58         if (offset + 2 > packet_len)
59                 goto bad;
60         hdr = (struct ipv6_opt_hdr *)(nh + offset);
61         len = ((hdr->hdrlen + 1) << 3);
62
63         if (offset + len > packet_len)
64                 goto bad;
65
66         offset += 2;
67         len -= 2;
68
69         while (len > 0) {
70                 int opttype = nh[offset];
71                 int optlen;
72
73                 if (opttype == type)
74                         return offset;
75
76                 switch (opttype) {
77                 case IPV6_TLV_PAD0:
78                         optlen = 1;
79                         break;
80                 default:
81                         optlen = nh[offset + 1] + 2;
82                         if (optlen > len)
83                                 goto bad;
84                         break;
85                 }
86                 offset += optlen;
87                 len -= optlen;
88         }
89         /* not_found */
90  bad:
91         return -1;
92 }
93 EXPORT_SYMBOL_GPL(ipv6_find_tlv);
94
95 /*
96  *      Parsing tlv encoded headers.
97  *
98  *      Parsing function "func" returns 1, if parsing succeed
99  *      and 0, if it failed.
100  *      It MUST NOT touch skb->h.
101  */
102
103 struct tlvtype_proc {
104         int     type;
105         int     (*func)(struct sk_buff *skb, int offset);
106 };
107
108 /*********************
109   Generic functions
110  *********************/
111
112 /* An unknown option is detected, decide what to do */
113
114 static int ip6_tlvopt_unknown(struct sk_buff *skb, int optoff)
115 {
116         switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) {
117         case 0: /* ignore */
118                 return 1;
119
120         case 1: /* drop packet */
121                 break;
122
123         case 3: /* Send ICMP if not a multicast address and drop packet */
124                 /* Actually, it is redundant check. icmp_send
125                    will recheck in any case.
126                  */
127                 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr))
128                         break;
129         case 2: /* send ICMP PARM PROB regardless and drop packet */
130                 icmpv6_param_prob(skb, ICMPV6_UNK_OPTION, optoff);
131                 return 0;
132         }
133
134         kfree_skb(skb);
135         return 0;
136 }
137
138 /* Parse tlv encoded option header (hop-by-hop or destination) */
139
140 static int ip6_parse_tlv(struct tlvtype_proc *procs, struct sk_buff *skb)
141 {
142         struct tlvtype_proc *curr;
143         const unsigned char *nh = skb_network_header(skb);
144         int off = skb_network_header_len(skb);
145         int len = (skb_transport_header(skb)[1] + 1) << 3;
146
147         if (skb_transport_offset(skb) + len > skb_headlen(skb))
148                 goto bad;
149
150         off += 2;
151         len -= 2;
152
153         while (len > 0) {
154                 int optlen = nh[off + 1] + 2;
155
156                 switch (nh[off]) {
157                 case IPV6_TLV_PAD0:
158                         optlen = 1;
159                         break;
160
161                 case IPV6_TLV_PADN:
162                         break;
163
164                 default: /* Other TLV code so scan list */
165                         if (optlen > len)
166                                 goto bad;
167                         for (curr=procs; curr->type >= 0; curr++) {
168                                 if (curr->type == nh[off]) {
169                                         /* type specific length/alignment
170                                            checks will be performed in the
171                                            func(). */
172                                         if (curr->func(skb, off) == 0)
173                                                 return 0;
174                                         break;
175                                 }
176                         }
177                         if (curr->type < 0) {
178                                 if (ip6_tlvopt_unknown(skb, off) == 0)
179                                         return 0;
180                         }
181                         break;
182                 }
183                 off += optlen;
184                 len -= optlen;
185         }
186         if (len == 0)
187                 return 1;
188 bad:
189         kfree_skb(skb);
190         return 0;
191 }
192
193 /*****************************
194   Destination options header.
195  *****************************/
196
197 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
198 static int ipv6_dest_hao(struct sk_buff *skb, int optoff)
199 {
200         struct ipv6_destopt_hao *hao;
201         struct inet6_skb_parm *opt = IP6CB(skb);
202         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
203         struct in6_addr tmp_addr;
204         int ret;
205
206         if (opt->dsthao) {
207                 LIMIT_NETDEBUG(KERN_DEBUG "hao duplicated\n");
208                 goto discard;
209         }
210         opt->dsthao = opt->dst1;
211         opt->dst1 = 0;
212
213         hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff);
214
215         if (hao->length != 16) {
216                 LIMIT_NETDEBUG(
217                         KERN_DEBUG "hao invalid option length = %d\n", hao->length);
218                 goto discard;
219         }
220
221         if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) {
222                 LIMIT_NETDEBUG(
223                         KERN_DEBUG "hao is not an unicast addr: %pI6\n", &hao->addr);
224                 goto discard;
225         }
226
227         ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr,
228                                (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS);
229         if (unlikely(ret < 0))
230                 goto discard;
231
232         if (skb_cloned(skb)) {
233                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
234                         goto discard;
235
236                 /* update all variable using below by copied skbuff */
237                 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) +
238                                                   optoff);
239                 ipv6h = ipv6_hdr(skb);
240         }
241
242         if (skb->ip_summed == CHECKSUM_COMPLETE)
243                 skb->ip_summed = CHECKSUM_NONE;
244
245         ipv6_addr_copy(&tmp_addr, &ipv6h->saddr);
246         ipv6_addr_copy(&ipv6h->saddr, &hao->addr);
247         ipv6_addr_copy(&hao->addr, &tmp_addr);
248
249         if (skb->tstamp.tv64 == 0)
250                 __net_timestamp(skb);
251
252         return 1;
253
254  discard:
255         kfree_skb(skb);
256         return 0;
257 }
258 #endif
259
260 static struct tlvtype_proc tlvprocdestopt_lst[] = {
261 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
262         {
263                 .type   = IPV6_TLV_HAO,
264                 .func   = ipv6_dest_hao,
265         },
266 #endif
267         {-1,                    NULL}
268 };
269
270 static int ipv6_destopt_rcv(struct sk_buff *skb)
271 {
272         struct inet6_skb_parm *opt = IP6CB(skb);
273 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
274         __u16 dstbuf;
275 #endif
276         struct dst_entry *dst = skb_dst(skb);
277
278         if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
279             !pskb_may_pull(skb, (skb_transport_offset(skb) +
280                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
281                 IP6_INC_STATS_BH(dev_net(dst->dev), ip6_dst_idev(dst),
282                                  IPSTATS_MIB_INHDRERRORS);
283                 kfree_skb(skb);
284                 return -1;
285         }
286
287         opt->lastopt = opt->dst1 = skb_network_header_len(skb);
288 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
289         dstbuf = opt->dst1;
290 #endif
291
292         if (ip6_parse_tlv(tlvprocdestopt_lst, skb)) {
293                 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
294                 opt = IP6CB(skb);
295 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
296                 opt->nhoff = dstbuf;
297 #else
298                 opt->nhoff = opt->dst1;
299 #endif
300                 return 1;
301         }
302
303         IP6_INC_STATS_BH(dev_net(dst->dev),
304                          ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS);
305         return -1;
306 }
307
308 /********************************
309   Routing header.
310  ********************************/
311
312 /* called with rcu_read_lock() */
313 static int ipv6_rthdr_rcv(struct sk_buff *skb)
314 {
315         struct inet6_skb_parm *opt = IP6CB(skb);
316         struct in6_addr *addr = NULL;
317         struct in6_addr daddr;
318         struct inet6_dev *idev;
319         int n, i;
320         struct ipv6_rt_hdr *hdr;
321         struct rt0_hdr *rthdr;
322         struct net *net = dev_net(skb->dev);
323         int accept_source_route = net->ipv6.devconf_all->accept_source_route;
324
325         idev = __in6_dev_get(skb->dev);
326         if (idev && accept_source_route > idev->cnf.accept_source_route)
327                 accept_source_route = idev->cnf.accept_source_route;
328
329         if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
330             !pskb_may_pull(skb, (skb_transport_offset(skb) +
331                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
332                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
333                                  IPSTATS_MIB_INHDRERRORS);
334                 kfree_skb(skb);
335                 return -1;
336         }
337
338         hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
339
340         if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
341             skb->pkt_type != PACKET_HOST) {
342                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
343                                  IPSTATS_MIB_INADDRERRORS);
344                 kfree_skb(skb);
345                 return -1;
346         }
347
348 looped_back:
349         if (hdr->segments_left == 0) {
350                 switch (hdr->type) {
351 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
352                 case IPV6_SRCRT_TYPE_2:
353                         /* Silently discard type 2 header unless it was
354                          * processed by own
355                          */
356                         if (!addr) {
357                                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
358                                                  IPSTATS_MIB_INADDRERRORS);
359                                 kfree_skb(skb);
360                                 return -1;
361                         }
362                         break;
363 #endif
364                 default:
365                         break;
366                 }
367
368                 opt->lastopt = opt->srcrt = skb_network_header_len(skb);
369                 skb->transport_header += (hdr->hdrlen + 1) << 3;
370                 opt->dst0 = opt->dst1;
371                 opt->dst1 = 0;
372                 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
373                 return 1;
374         }
375
376         switch (hdr->type) {
377 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
378         case IPV6_SRCRT_TYPE_2:
379                 if (accept_source_route < 0)
380                         goto unknown_rh;
381                 /* Silently discard invalid RTH type 2 */
382                 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
383                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
384                                          IPSTATS_MIB_INHDRERRORS);
385                         kfree_skb(skb);
386                         return -1;
387                 }
388                 break;
389 #endif
390         default:
391                 goto unknown_rh;
392         }
393
394         /*
395          *      This is the routing header forwarding algorithm from
396          *      RFC 2460, page 16.
397          */
398
399         n = hdr->hdrlen >> 1;
400
401         if (hdr->segments_left > n) {
402                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
403                                  IPSTATS_MIB_INHDRERRORS);
404                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
405                                   ((&hdr->segments_left) -
406                                    skb_network_header(skb)));
407                 return -1;
408         }
409
410         /* We are about to mangle packet header. Be careful!
411            Do not damage packets queued somewhere.
412          */
413         if (skb_cloned(skb)) {
414                 /* the copy is a forwarded packet */
415                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
416                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
417                                          IPSTATS_MIB_OUTDISCARDS);
418                         kfree_skb(skb);
419                         return -1;
420                 }
421                 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
422         }
423
424         if (skb->ip_summed == CHECKSUM_COMPLETE)
425                 skb->ip_summed = CHECKSUM_NONE;
426
427         i = n - --hdr->segments_left;
428
429         rthdr = (struct rt0_hdr *) hdr;
430         addr = rthdr->addr;
431         addr += i - 1;
432
433         switch (hdr->type) {
434 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
435         case IPV6_SRCRT_TYPE_2:
436                 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
437                                      (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
438                                      IPPROTO_ROUTING) < 0) {
439                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
440                                          IPSTATS_MIB_INADDRERRORS);
441                         kfree_skb(skb);
442                         return -1;
443                 }
444                 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) {
445                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
446                                          IPSTATS_MIB_INADDRERRORS);
447                         kfree_skb(skb);
448                         return -1;
449                 }
450                 break;
451 #endif
452         default:
453                 break;
454         }
455
456         if (ipv6_addr_is_multicast(addr)) {
457                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
458                                  IPSTATS_MIB_INADDRERRORS);
459                 kfree_skb(skb);
460                 return -1;
461         }
462
463         ipv6_addr_copy(&daddr, addr);
464         ipv6_addr_copy(addr, &ipv6_hdr(skb)->daddr);
465         ipv6_addr_copy(&ipv6_hdr(skb)->daddr, &daddr);
466
467         skb_dst_drop(skb);
468         ip6_route_input(skb);
469         if (skb_dst(skb)->error) {
470                 skb_push(skb, skb->data - skb_network_header(skb));
471                 dst_input(skb);
472                 return -1;
473         }
474
475         if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) {
476                 if (ipv6_hdr(skb)->hop_limit <= 1) {
477                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
478                                          IPSTATS_MIB_INHDRERRORS);
479                         icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
480                                     0);
481                         kfree_skb(skb);
482                         return -1;
483                 }
484                 ipv6_hdr(skb)->hop_limit--;
485                 goto looped_back;
486         }
487
488         skb_push(skb, skb->data - skb_network_header(skb));
489         dst_input(skb);
490         return -1;
491
492 unknown_rh:
493         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INHDRERRORS);
494         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
495                           (&hdr->type) - skb_network_header(skb));
496         return -1;
497 }
498
499 static const struct inet6_protocol rthdr_protocol = {
500         .handler        =       ipv6_rthdr_rcv,
501         .flags          =       INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
502 };
503
504 static const struct inet6_protocol destopt_protocol = {
505         .handler        =       ipv6_destopt_rcv,
506         .flags          =       INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
507 };
508
509 static const struct inet6_protocol nodata_protocol = {
510         .handler        =       dst_discard,
511         .flags          =       INET6_PROTO_NOPOLICY,
512 };
513
514 int __init ipv6_exthdrs_init(void)
515 {
516         int ret;
517
518         ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
519         if (ret)
520                 goto out;
521
522         ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
523         if (ret)
524                 goto out_rthdr;
525
526         ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
527         if (ret)
528                 goto out_destopt;
529
530 out:
531         return ret;
532 out_rthdr:
533         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
534 out_destopt:
535         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
536         goto out;
537 };
538
539 void ipv6_exthdrs_exit(void)
540 {
541         inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
542         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
543         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
544 }
545
546 /**********************************
547   Hop-by-hop options.
548  **********************************/
549
550 /*
551  * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input().
552  */
553 static inline struct inet6_dev *ipv6_skb_idev(struct sk_buff *skb)
554 {
555         return skb_dst(skb) ? ip6_dst_idev(skb_dst(skb)) : __in6_dev_get(skb->dev);
556 }
557
558 static inline struct net *ipv6_skb_net(struct sk_buff *skb)
559 {
560         return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev);
561 }
562
563 /* Router Alert as of RFC 2711 */
564
565 static int ipv6_hop_ra(struct sk_buff *skb, int optoff)
566 {
567         const unsigned char *nh = skb_network_header(skb);
568
569         if (nh[optoff + 1] == 2) {
570                 IP6CB(skb)->ra = optoff;
571                 return 1;
572         }
573         LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_ra: wrong RA length %d\n",
574                        nh[optoff + 1]);
575         kfree_skb(skb);
576         return 0;
577 }
578
579 /* Jumbo payload */
580
581 static int ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
582 {
583         const unsigned char *nh = skb_network_header(skb);
584         struct net *net = ipv6_skb_net(skb);
585         u32 pkt_len;
586
587         if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
588                 LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
589                                nh[optoff+1]);
590                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
591                                  IPSTATS_MIB_INHDRERRORS);
592                 goto drop;
593         }
594
595         pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
596         if (pkt_len <= IPV6_MAXPLEN) {
597                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
598                                  IPSTATS_MIB_INHDRERRORS);
599                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
600                 return 0;
601         }
602         if (ipv6_hdr(skb)->payload_len) {
603                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
604                                  IPSTATS_MIB_INHDRERRORS);
605                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
606                 return 0;
607         }
608
609         if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
610                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
611                                  IPSTATS_MIB_INTRUNCATEDPKTS);
612                 goto drop;
613         }
614
615         if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
616                 goto drop;
617
618         return 1;
619
620 drop:
621         kfree_skb(skb);
622         return 0;
623 }
624
625 static struct tlvtype_proc tlvprochopopt_lst[] = {
626         {
627                 .type   = IPV6_TLV_ROUTERALERT,
628                 .func   = ipv6_hop_ra,
629         },
630         {
631                 .type   = IPV6_TLV_JUMBO,
632                 .func   = ipv6_hop_jumbo,
633         },
634         { -1, }
635 };
636
637 int ipv6_parse_hopopts(struct sk_buff *skb)
638 {
639         struct inet6_skb_parm *opt = IP6CB(skb);
640
641         /*
642          * skb_network_header(skb) is equal to skb->data, and
643          * skb_network_header_len(skb) is always equal to
644          * sizeof(struct ipv6hdr) by definition of
645          * hop-by-hop options.
646          */
647         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
648             !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
649                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
650                 kfree_skb(skb);
651                 return -1;
652         }
653
654         opt->hop = sizeof(struct ipv6hdr);
655         if (ip6_parse_tlv(tlvprochopopt_lst, skb)) {
656                 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
657                 opt = IP6CB(skb);
658                 opt->nhoff = sizeof(struct ipv6hdr);
659                 return 1;
660         }
661         return -1;
662 }
663
664 /*
665  *      Creating outbound headers.
666  *
667  *      "build" functions work when skb is filled from head to tail (datagram)
668  *      "push"  functions work when headers are added from tail to head (tcp)
669  *
670  *      In both cases we assume, that caller reserved enough room
671  *      for headers.
672  */
673
674 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
675                             struct ipv6_rt_hdr *opt,
676                             struct in6_addr **addr_p)
677 {
678         struct rt0_hdr *phdr, *ihdr;
679         int hops;
680
681         ihdr = (struct rt0_hdr *) opt;
682
683         phdr = (struct rt0_hdr *) skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
684         memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
685
686         hops = ihdr->rt_hdr.hdrlen >> 1;
687
688         if (hops > 1)
689                 memcpy(phdr->addr, ihdr->addr + 1,
690                        (hops - 1) * sizeof(struct in6_addr));
691
692         ipv6_addr_copy(phdr->addr + (hops - 1), *addr_p);
693         *addr_p = ihdr->addr;
694
695         phdr->rt_hdr.nexthdr = *proto;
696         *proto = NEXTHDR_ROUTING;
697 }
698
699 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
700 {
701         struct ipv6_opt_hdr *h = (struct ipv6_opt_hdr *)skb_push(skb, ipv6_optlen(opt));
702
703         memcpy(h, opt, ipv6_optlen(opt));
704         h->nexthdr = *proto;
705         *proto = type;
706 }
707
708 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
709                           u8 *proto,
710                           struct in6_addr **daddr)
711 {
712         if (opt->srcrt) {
713                 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr);
714                 /*
715                  * IPV6_RTHDRDSTOPTS is ignored
716                  * unless IPV6_RTHDR is set (RFC3542).
717                  */
718                 if (opt->dst0opt)
719                         ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
720         }
721         if (opt->hopopt)
722                 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
723 }
724
725 EXPORT_SYMBOL(ipv6_push_nfrag_opts);
726
727 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
728 {
729         if (opt->dst1opt)
730                 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
731 }
732
733 struct ipv6_txoptions *
734 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
735 {
736         struct ipv6_txoptions *opt2;
737
738         opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
739         if (opt2) {
740                 long dif = (char*)opt2 - (char*)opt;
741                 memcpy(opt2, opt, opt->tot_len);
742                 if (opt2->hopopt)
743                         *((char**)&opt2->hopopt) += dif;
744                 if (opt2->dst0opt)
745                         *((char**)&opt2->dst0opt) += dif;
746                 if (opt2->dst1opt)
747                         *((char**)&opt2->dst1opt) += dif;
748                 if (opt2->srcrt)
749                         *((char**)&opt2->srcrt) += dif;
750         }
751         return opt2;
752 }
753
754 EXPORT_SYMBOL_GPL(ipv6_dup_options);
755
756 static int ipv6_renew_option(void *ohdr,
757                              struct ipv6_opt_hdr __user *newopt, int newoptlen,
758                              int inherit,
759                              struct ipv6_opt_hdr **hdr,
760                              char **p)
761 {
762         if (inherit) {
763                 if (ohdr) {
764                         memcpy(*p, ohdr, ipv6_optlen((struct ipv6_opt_hdr *)ohdr));
765                         *hdr = (struct ipv6_opt_hdr *)*p;
766                         *p += CMSG_ALIGN(ipv6_optlen(*(struct ipv6_opt_hdr **)hdr));
767                 }
768         } else {
769                 if (newopt) {
770                         if (copy_from_user(*p, newopt, newoptlen))
771                                 return -EFAULT;
772                         *hdr = (struct ipv6_opt_hdr *)*p;
773                         if (ipv6_optlen(*(struct ipv6_opt_hdr **)hdr) > newoptlen)
774                                 return -EINVAL;
775                         *p += CMSG_ALIGN(newoptlen);
776                 }
777         }
778         return 0;
779 }
780
781 struct ipv6_txoptions *
782 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
783                    int newtype,
784                    struct ipv6_opt_hdr __user *newopt, int newoptlen)
785 {
786         int tot_len = 0;
787         char *p;
788         struct ipv6_txoptions *opt2;
789         int err;
790
791         if (opt) {
792                 if (newtype != IPV6_HOPOPTS && opt->hopopt)
793                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
794                 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
795                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
796                 if (newtype != IPV6_RTHDR && opt->srcrt)
797                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
798                 if (newtype != IPV6_DSTOPTS && opt->dst1opt)
799                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
800         }
801
802         if (newopt && newoptlen)
803                 tot_len += CMSG_ALIGN(newoptlen);
804
805         if (!tot_len)
806                 return NULL;
807
808         tot_len += sizeof(*opt2);
809         opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
810         if (!opt2)
811                 return ERR_PTR(-ENOBUFS);
812
813         memset(opt2, 0, tot_len);
814
815         opt2->tot_len = tot_len;
816         p = (char *)(opt2 + 1);
817
818         err = ipv6_renew_option(opt ? opt->hopopt : NULL, newopt, newoptlen,
819                                 newtype != IPV6_HOPOPTS,
820                                 &opt2->hopopt, &p);
821         if (err)
822                 goto out;
823
824         err = ipv6_renew_option(opt ? opt->dst0opt : NULL, newopt, newoptlen,
825                                 newtype != IPV6_RTHDRDSTOPTS,
826                                 &opt2->dst0opt, &p);
827         if (err)
828                 goto out;
829
830         err = ipv6_renew_option(opt ? opt->srcrt : NULL, newopt, newoptlen,
831                                 newtype != IPV6_RTHDR,
832                                 (struct ipv6_opt_hdr **)&opt2->srcrt, &p);
833         if (err)
834                 goto out;
835
836         err = ipv6_renew_option(opt ? opt->dst1opt : NULL, newopt, newoptlen,
837                                 newtype != IPV6_DSTOPTS,
838                                 &opt2->dst1opt, &p);
839         if (err)
840                 goto out;
841
842         opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
843                           (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
844                           (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
845         opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
846
847         return opt2;
848 out:
849         sock_kfree_s(sk, opt2, opt2->tot_len);
850         return ERR_PTR(err);
851 }
852
853 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
854                                           struct ipv6_txoptions *opt)
855 {
856         /*
857          * ignore the dest before srcrt unless srcrt is being included.
858          * --yoshfuji
859          */
860         if (opt && opt->dst0opt && !opt->srcrt) {
861                 if (opt_space != opt) {
862                         memcpy(opt_space, opt, sizeof(*opt_space));
863                         opt = opt_space;
864                 }
865                 opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
866                 opt->dst0opt = NULL;
867         }
868
869         return opt;
870 }
871
872 /**
873  * fl6_update_dst - update flowi destination address with info given
874  *                  by srcrt option, if any.
875  *
876  * @fl6: flowi6 for which daddr is to be updated
877  * @opt: struct ipv6_txoptions in which to look for srcrt opt
878  * @orig: copy of original daddr address if modified
879  *
880  * Returns NULL if no txoptions or no srcrt, otherwise returns orig
881  * and initial value of fl6->daddr set in orig
882  */
883 struct in6_addr *fl6_update_dst(struct flowi6 *fl6,
884                                 const struct ipv6_txoptions *opt,
885                                 struct in6_addr *orig)
886 {
887         if (!opt || !opt->srcrt)
888                 return NULL;
889
890         ipv6_addr_copy(orig, &fl6->daddr);
891         ipv6_addr_copy(&fl6->daddr, ((struct rt0_hdr *)opt->srcrt)->addr);
892         return orig;
893 }
894
895 EXPORT_SYMBOL_GPL(fl6_update_dst);