sctp: Do not account for sizeof(struct sk_buff) in estimated rwnd
[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 #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;
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(skb_dst(skb)->dev), ip6_dst_idev(skb_dst(skb)),
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         dst = dst_clone(skb_dst(skb));
293         if (ip6_parse_tlv(tlvprocdestopt_lst, skb)) {
294                 dst_release(dst);
295                 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
296                 opt = IP6CB(skb);
297 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
298                 opt->nhoff = dstbuf;
299 #else
300                 opt->nhoff = opt->dst1;
301 #endif
302                 return 1;
303         }
304
305         IP6_INC_STATS_BH(dev_net(dst->dev),
306                          ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS);
307         dst_release(dst);
308         return -1;
309 }
310
311 /********************************
312   Routing header.
313  ********************************/
314
315 /* called with rcu_read_lock() */
316 static int ipv6_rthdr_rcv(struct sk_buff *skb)
317 {
318         struct inet6_skb_parm *opt = IP6CB(skb);
319         struct in6_addr *addr = NULL;
320         struct in6_addr daddr;
321         struct inet6_dev *idev;
322         int n, i;
323         struct ipv6_rt_hdr *hdr;
324         struct rt0_hdr *rthdr;
325         struct net *net = dev_net(skb->dev);
326         int accept_source_route = net->ipv6.devconf_all->accept_source_route;
327
328         idev = __in6_dev_get(skb->dev);
329         if (idev && accept_source_route > idev->cnf.accept_source_route)
330                 accept_source_route = idev->cnf.accept_source_route;
331
332         if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
333             !pskb_may_pull(skb, (skb_transport_offset(skb) +
334                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
335                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
336                                  IPSTATS_MIB_INHDRERRORS);
337                 kfree_skb(skb);
338                 return -1;
339         }
340
341         hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
342
343         if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
344             skb->pkt_type != PACKET_HOST) {
345                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
346                                  IPSTATS_MIB_INADDRERRORS);
347                 kfree_skb(skb);
348                 return -1;
349         }
350
351 looped_back:
352         if (hdr->segments_left == 0) {
353                 switch (hdr->type) {
354 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
355                 case IPV6_SRCRT_TYPE_2:
356                         /* Silently discard type 2 header unless it was
357                          * processed by own
358                          */
359                         if (!addr) {
360                                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
361                                                  IPSTATS_MIB_INADDRERRORS);
362                                 kfree_skb(skb);
363                                 return -1;
364                         }
365                         break;
366 #endif
367                 default:
368                         break;
369                 }
370
371                 opt->lastopt = opt->srcrt = skb_network_header_len(skb);
372                 skb->transport_header += (hdr->hdrlen + 1) << 3;
373                 opt->dst0 = opt->dst1;
374                 opt->dst1 = 0;
375                 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
376                 return 1;
377         }
378
379         switch (hdr->type) {
380 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
381         case IPV6_SRCRT_TYPE_2:
382                 if (accept_source_route < 0)
383                         goto unknown_rh;
384                 /* Silently discard invalid RTH type 2 */
385                 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
386                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
387                                          IPSTATS_MIB_INHDRERRORS);
388                         kfree_skb(skb);
389                         return -1;
390                 }
391                 break;
392 #endif
393         default:
394                 goto unknown_rh;
395         }
396
397         /*
398          *      This is the routing header forwarding algorithm from
399          *      RFC 2460, page 16.
400          */
401
402         n = hdr->hdrlen >> 1;
403
404         if (hdr->segments_left > n) {
405                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
406                                  IPSTATS_MIB_INHDRERRORS);
407                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
408                                   ((&hdr->segments_left) -
409                                    skb_network_header(skb)));
410                 return -1;
411         }
412
413         /* We are about to mangle packet header. Be careful!
414            Do not damage packets queued somewhere.
415          */
416         if (skb_cloned(skb)) {
417                 /* the copy is a forwarded packet */
418                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
419                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
420                                          IPSTATS_MIB_OUTDISCARDS);
421                         kfree_skb(skb);
422                         return -1;
423                 }
424                 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
425         }
426
427         if (skb->ip_summed == CHECKSUM_COMPLETE)
428                 skb->ip_summed = CHECKSUM_NONE;
429
430         i = n - --hdr->segments_left;
431
432         rthdr = (struct rt0_hdr *) hdr;
433         addr = rthdr->addr;
434         addr += i - 1;
435
436         switch (hdr->type) {
437 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
438         case IPV6_SRCRT_TYPE_2:
439                 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
440                                      (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
441                                      IPPROTO_ROUTING) < 0) {
442                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
443                                          IPSTATS_MIB_INADDRERRORS);
444                         kfree_skb(skb);
445                         return -1;
446                 }
447                 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) {
448                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
449                                          IPSTATS_MIB_INADDRERRORS);
450                         kfree_skb(skb);
451                         return -1;
452                 }
453                 break;
454 #endif
455         default:
456                 break;
457         }
458
459         if (ipv6_addr_is_multicast(addr)) {
460                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
461                                  IPSTATS_MIB_INADDRERRORS);
462                 kfree_skb(skb);
463                 return -1;
464         }
465
466         ipv6_addr_copy(&daddr, addr);
467         ipv6_addr_copy(addr, &ipv6_hdr(skb)->daddr);
468         ipv6_addr_copy(&ipv6_hdr(skb)->daddr, &daddr);
469
470         skb_dst_drop(skb);
471         ip6_route_input(skb);
472         if (skb_dst(skb)->error) {
473                 skb_push(skb, skb->data - skb_network_header(skb));
474                 dst_input(skb);
475                 return -1;
476         }
477
478         if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) {
479                 if (ipv6_hdr(skb)->hop_limit <= 1) {
480                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
481                                          IPSTATS_MIB_INHDRERRORS);
482                         icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
483                                     0);
484                         kfree_skb(skb);
485                         return -1;
486                 }
487                 ipv6_hdr(skb)->hop_limit--;
488                 goto looped_back;
489         }
490
491         skb_push(skb, skb->data - skb_network_header(skb));
492         dst_input(skb);
493         return -1;
494
495 unknown_rh:
496         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INHDRERRORS);
497         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
498                           (&hdr->type) - skb_network_header(skb));
499         return -1;
500 }
501
502 static const struct inet6_protocol rthdr_protocol = {
503         .handler        =       ipv6_rthdr_rcv,
504         .flags          =       INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
505 };
506
507 static const struct inet6_protocol destopt_protocol = {
508         .handler        =       ipv6_destopt_rcv,
509         .flags          =       INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
510 };
511
512 static const struct inet6_protocol nodata_protocol = {
513         .handler        =       dst_discard,
514         .flags          =       INET6_PROTO_NOPOLICY,
515 };
516
517 int __init ipv6_exthdrs_init(void)
518 {
519         int ret;
520
521         ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
522         if (ret)
523                 goto out;
524
525         ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
526         if (ret)
527                 goto out_rthdr;
528
529         ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
530         if (ret)
531                 goto out_destopt;
532
533 out:
534         return ret;
535 out_rthdr:
536         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
537 out_destopt:
538         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
539         goto out;
540 };
541
542 void ipv6_exthdrs_exit(void)
543 {
544         inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
545         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
546         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
547 }
548
549 /**********************************
550   Hop-by-hop options.
551  **********************************/
552
553 /*
554  * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input().
555  */
556 static inline struct inet6_dev *ipv6_skb_idev(struct sk_buff *skb)
557 {
558         return skb_dst(skb) ? ip6_dst_idev(skb_dst(skb)) : __in6_dev_get(skb->dev);
559 }
560
561 static inline struct net *ipv6_skb_net(struct sk_buff *skb)
562 {
563         return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev);
564 }
565
566 /* Router Alert as of RFC 2711 */
567
568 static int ipv6_hop_ra(struct sk_buff *skb, int optoff)
569 {
570         const unsigned char *nh = skb_network_header(skb);
571
572         if (nh[optoff + 1] == 2) {
573                 IP6CB(skb)->ra = optoff;
574                 return 1;
575         }
576         LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_ra: wrong RA length %d\n",
577                        nh[optoff + 1]);
578         kfree_skb(skb);
579         return 0;
580 }
581
582 /* Jumbo payload */
583
584 static int ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
585 {
586         const unsigned char *nh = skb_network_header(skb);
587         struct net *net = ipv6_skb_net(skb);
588         u32 pkt_len;
589
590         if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
591                 LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
592                                nh[optoff+1]);
593                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
594                                  IPSTATS_MIB_INHDRERRORS);
595                 goto drop;
596         }
597
598         pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
599         if (pkt_len <= IPV6_MAXPLEN) {
600                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
601                                  IPSTATS_MIB_INHDRERRORS);
602                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
603                 return 0;
604         }
605         if (ipv6_hdr(skb)->payload_len) {
606                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
607                                  IPSTATS_MIB_INHDRERRORS);
608                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
609                 return 0;
610         }
611
612         if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
613                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
614                                  IPSTATS_MIB_INTRUNCATEDPKTS);
615                 goto drop;
616         }
617
618         if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
619                 goto drop;
620
621         return 1;
622
623 drop:
624         kfree_skb(skb);
625         return 0;
626 }
627
628 static struct tlvtype_proc tlvprochopopt_lst[] = {
629         {
630                 .type   = IPV6_TLV_ROUTERALERT,
631                 .func   = ipv6_hop_ra,
632         },
633         {
634                 .type   = IPV6_TLV_JUMBO,
635                 .func   = ipv6_hop_jumbo,
636         },
637         { -1, }
638 };
639
640 int ipv6_parse_hopopts(struct sk_buff *skb)
641 {
642         struct inet6_skb_parm *opt = IP6CB(skb);
643
644         /*
645          * skb_network_header(skb) is equal to skb->data, and
646          * skb_network_header_len(skb) is always equal to
647          * sizeof(struct ipv6hdr) by definition of
648          * hop-by-hop options.
649          */
650         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
651             !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
652                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
653                 kfree_skb(skb);
654                 return -1;
655         }
656
657         opt->hop = sizeof(struct ipv6hdr);
658         if (ip6_parse_tlv(tlvprochopopt_lst, skb)) {
659                 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
660                 opt = IP6CB(skb);
661                 opt->nhoff = sizeof(struct ipv6hdr);
662                 return 1;
663         }
664         return -1;
665 }
666
667 /*
668  *      Creating outbound headers.
669  *
670  *      "build" functions work when skb is filled from head to tail (datagram)
671  *      "push"  functions work when headers are added from tail to head (tcp)
672  *
673  *      In both cases we assume, that caller reserved enough room
674  *      for headers.
675  */
676
677 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
678                             struct ipv6_rt_hdr *opt,
679                             struct in6_addr **addr_p)
680 {
681         struct rt0_hdr *phdr, *ihdr;
682         int hops;
683
684         ihdr = (struct rt0_hdr *) opt;
685
686         phdr = (struct rt0_hdr *) skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
687         memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
688
689         hops = ihdr->rt_hdr.hdrlen >> 1;
690
691         if (hops > 1)
692                 memcpy(phdr->addr, ihdr->addr + 1,
693                        (hops - 1) * sizeof(struct in6_addr));
694
695         ipv6_addr_copy(phdr->addr + (hops - 1), *addr_p);
696         *addr_p = ihdr->addr;
697
698         phdr->rt_hdr.nexthdr = *proto;
699         *proto = NEXTHDR_ROUTING;
700 }
701
702 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
703 {
704         struct ipv6_opt_hdr *h = (struct ipv6_opt_hdr *)skb_push(skb, ipv6_optlen(opt));
705
706         memcpy(h, opt, ipv6_optlen(opt));
707         h->nexthdr = *proto;
708         *proto = type;
709 }
710
711 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
712                           u8 *proto,
713                           struct in6_addr **daddr)
714 {
715         if (opt->srcrt) {
716                 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr);
717                 /*
718                  * IPV6_RTHDRDSTOPTS is ignored
719                  * unless IPV6_RTHDR is set (RFC3542).
720                  */
721                 if (opt->dst0opt)
722                         ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
723         }
724         if (opt->hopopt)
725                 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
726 }
727
728 EXPORT_SYMBOL(ipv6_push_nfrag_opts);
729
730 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
731 {
732         if (opt->dst1opt)
733                 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
734 }
735
736 struct ipv6_txoptions *
737 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
738 {
739         struct ipv6_txoptions *opt2;
740
741         opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
742         if (opt2) {
743                 long dif = (char*)opt2 - (char*)opt;
744                 memcpy(opt2, opt, opt->tot_len);
745                 if (opt2->hopopt)
746                         *((char**)&opt2->hopopt) += dif;
747                 if (opt2->dst0opt)
748                         *((char**)&opt2->dst0opt) += dif;
749                 if (opt2->dst1opt)
750                         *((char**)&opt2->dst1opt) += dif;
751                 if (opt2->srcrt)
752                         *((char**)&opt2->srcrt) += dif;
753         }
754         return opt2;
755 }
756
757 EXPORT_SYMBOL_GPL(ipv6_dup_options);
758
759 static int ipv6_renew_option(void *ohdr,
760                              struct ipv6_opt_hdr __user *newopt, int newoptlen,
761                              int inherit,
762                              struct ipv6_opt_hdr **hdr,
763                              char **p)
764 {
765         if (inherit) {
766                 if (ohdr) {
767                         memcpy(*p, ohdr, ipv6_optlen((struct ipv6_opt_hdr *)ohdr));
768                         *hdr = (struct ipv6_opt_hdr *)*p;
769                         *p += CMSG_ALIGN(ipv6_optlen(*(struct ipv6_opt_hdr **)hdr));
770                 }
771         } else {
772                 if (newopt) {
773                         if (copy_from_user(*p, newopt, newoptlen))
774                                 return -EFAULT;
775                         *hdr = (struct ipv6_opt_hdr *)*p;
776                         if (ipv6_optlen(*(struct ipv6_opt_hdr **)hdr) > newoptlen)
777                                 return -EINVAL;
778                         *p += CMSG_ALIGN(newoptlen);
779                 }
780         }
781         return 0;
782 }
783
784 struct ipv6_txoptions *
785 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
786                    int newtype,
787                    struct ipv6_opt_hdr __user *newopt, int newoptlen)
788 {
789         int tot_len = 0;
790         char *p;
791         struct ipv6_txoptions *opt2;
792         int err;
793
794         if (opt) {
795                 if (newtype != IPV6_HOPOPTS && opt->hopopt)
796                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
797                 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
798                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
799                 if (newtype != IPV6_RTHDR && opt->srcrt)
800                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
801                 if (newtype != IPV6_DSTOPTS && opt->dst1opt)
802                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
803         }
804
805         if (newopt && newoptlen)
806                 tot_len += CMSG_ALIGN(newoptlen);
807
808         if (!tot_len)
809                 return NULL;
810
811         tot_len += sizeof(*opt2);
812         opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
813         if (!opt2)
814                 return ERR_PTR(-ENOBUFS);
815
816         memset(opt2, 0, tot_len);
817
818         opt2->tot_len = tot_len;
819         p = (char *)(opt2 + 1);
820
821         err = ipv6_renew_option(opt ? opt->hopopt : NULL, newopt, newoptlen,
822                                 newtype != IPV6_HOPOPTS,
823                                 &opt2->hopopt, &p);
824         if (err)
825                 goto out;
826
827         err = ipv6_renew_option(opt ? opt->dst0opt : NULL, newopt, newoptlen,
828                                 newtype != IPV6_RTHDRDSTOPTS,
829                                 &opt2->dst0opt, &p);
830         if (err)
831                 goto out;
832
833         err = ipv6_renew_option(opt ? opt->srcrt : NULL, newopt, newoptlen,
834                                 newtype != IPV6_RTHDR,
835                                 (struct ipv6_opt_hdr **)&opt2->srcrt, &p);
836         if (err)
837                 goto out;
838
839         err = ipv6_renew_option(opt ? opt->dst1opt : NULL, newopt, newoptlen,
840                                 newtype != IPV6_DSTOPTS,
841                                 &opt2->dst1opt, &p);
842         if (err)
843                 goto out;
844
845         opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
846                           (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
847                           (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
848         opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
849
850         return opt2;
851 out:
852         sock_kfree_s(sk, opt2, opt2->tot_len);
853         return ERR_PTR(err);
854 }
855
856 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
857                                           struct ipv6_txoptions *opt)
858 {
859         /*
860          * ignore the dest before srcrt unless srcrt is being included.
861          * --yoshfuji
862          */
863         if (opt && opt->dst0opt && !opt->srcrt) {
864                 if (opt_space != opt) {
865                         memcpy(opt_space, opt, sizeof(*opt_space));
866                         opt = opt_space;
867                 }
868                 opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
869                 opt->dst0opt = NULL;
870         }
871
872         return opt;
873 }
874
875 /**
876  * fl6_update_dst - update flowi destination address with info given
877  *                  by srcrt option, if any.
878  *
879  * @fl6: flowi6 for which daddr is to be updated
880  * @opt: struct ipv6_txoptions in which to look for srcrt opt
881  * @orig: copy of original daddr address if modified
882  *
883  * Returns NULL if no txoptions or no srcrt, otherwise returns orig
884  * and initial value of fl6->daddr set in orig
885  */
886 struct in6_addr *fl6_update_dst(struct flowi6 *fl6,
887                                 const struct ipv6_txoptions *opt,
888                                 struct in6_addr *orig)
889 {
890         if (!opt || !opt->srcrt)
891                 return NULL;
892
893         ipv6_addr_copy(orig, &fl6->daddr);
894         ipv6_addr_copy(&fl6->daddr, ((struct rt0_hdr *)opt->srcrt)->addr);
895         return orig;
896 }
897
898 EXPORT_SYMBOL_GPL(fl6_update_dst);