[INET]: Prevent out-of-sync truesize on ip_fragment slow path
[linux-2.6] / 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  *      $Id: exthdrs.c,v 1.13 2001/06/19 15:58:56 davem Exp $
11  *
12  *      This program is free software; you can redistribute it and/or
13  *      modify it under the terms of the GNU General Public License
14  *      as published by the Free Software Foundation; either version
15  *      2 of the License, or (at your option) any later version.
16  */
17
18 /* Changes:
19  *      yoshfuji                : ensure not to overrun while parsing
20  *                                tlv options.
21  *      Mitsuru KANDA @USAGI and: Remove ipv6_parse_exthdrs().
22  *      YOSHIFUJI Hideaki @USAGI  Register inbound extension header
23  *                                handlers as inet6_protocol{}.
24  */
25
26 #include <linux/errno.h>
27 #include <linux/types.h>
28 #include <linux/socket.h>
29 #include <linux/sockios.h>
30 #include <linux/net.h>
31 #include <linux/netdevice.h>
32 #include <linux/in6.h>
33 #include <linux/icmpv6.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: " NIP6_FMT "\n", NIP6(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;
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(ip6_dst_idev(skb->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         dst = dst_clone(skb->dst);
294         if (ip6_parse_tlv(tlvprocdestopt_lst, skb)) {
295                 dst_release(dst);
296                 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
297                 opt = IP6CB(skb);
298 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
299                 opt->nhoff = dstbuf;
300 #else
301                 opt->nhoff = opt->dst1;
302 #endif
303                 return 1;
304         }
305
306         IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS);
307         dst_release(dst);
308         return -1;
309 }
310
311 /********************************
312   Routing header.
313  ********************************/
314
315 static int ipv6_rthdr_rcv(struct sk_buff *skb)
316 {
317         struct inet6_skb_parm *opt = IP6CB(skb);
318         struct in6_addr *addr = NULL;
319         struct in6_addr daddr;
320         struct inet6_dev *idev;
321         int n, i;
322         struct ipv6_rt_hdr *hdr;
323         struct rt0_hdr *rthdr;
324         int accept_source_route = ipv6_devconf.accept_source_route;
325
326         idev = in6_dev_get(skb->dev);
327         if (idev) {
328                 if (accept_source_route > idev->cnf.accept_source_route)
329                         accept_source_route = idev->cnf.accept_source_route;
330                 in6_dev_put(idev);
331         }
332
333         if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
334             !pskb_may_pull(skb, (skb_transport_offset(skb) +
335                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
336                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
337                                  IPSTATS_MIB_INHDRERRORS);
338                 kfree_skb(skb);
339                 return -1;
340         }
341
342         hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
343
344         if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
345             skb->pkt_type != PACKET_HOST) {
346                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
347                                  IPSTATS_MIB_INADDRERRORS);
348                 kfree_skb(skb);
349                 return -1;
350         }
351
352 looped_back:
353         if (hdr->segments_left == 0) {
354                 switch (hdr->type) {
355 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
356                 case IPV6_SRCRT_TYPE_2:
357                         /* Silently discard type 2 header unless it was
358                          * processed by own
359                          */
360                         if (!addr) {
361                                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
362                                                  IPSTATS_MIB_INADDRERRORS);
363                                 kfree_skb(skb);
364                                 return -1;
365                         }
366                         break;
367 #endif
368                 default:
369                         break;
370                 }
371
372                 opt->lastopt = opt->srcrt = skb_network_header_len(skb);
373                 skb->transport_header += (hdr->hdrlen + 1) << 3;
374                 opt->dst0 = opt->dst1;
375                 opt->dst1 = 0;
376                 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
377                 return 1;
378         }
379
380         switch (hdr->type) {
381 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
382         case IPV6_SRCRT_TYPE_2:
383                 if (accept_source_route < 0)
384                         goto unknown_rh;
385                 /* Silently discard invalid RTH type 2 */
386                 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
387                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
388                                          IPSTATS_MIB_INHDRERRORS);
389                         kfree_skb(skb);
390                         return -1;
391                 }
392                 break;
393 #endif
394         default:
395                 goto unknown_rh;
396         }
397
398         /*
399          *      This is the routing header forwarding algorithm from
400          *      RFC 2460, page 16.
401          */
402
403         n = hdr->hdrlen >> 1;
404
405         if (hdr->segments_left > n) {
406                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
407                                  IPSTATS_MIB_INHDRERRORS);
408                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
409                                   ((&hdr->segments_left) -
410                                    skb_network_header(skb)));
411                 return -1;
412         }
413
414         /* We are about to mangle packet header. Be careful!
415            Do not damage packets queued somewhere.
416          */
417         if (skb_cloned(skb)) {
418                 /* the copy is a forwarded packet */
419                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
420                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
421                                          IPSTATS_MIB_OUTDISCARDS);
422                         kfree_skb(skb);
423                         return -1;
424                 }
425                 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
426         }
427
428         if (skb->ip_summed == CHECKSUM_COMPLETE)
429                 skb->ip_summed = CHECKSUM_NONE;
430
431         i = n - --hdr->segments_left;
432
433         rthdr = (struct rt0_hdr *) hdr;
434         addr = rthdr->addr;
435         addr += i - 1;
436
437         switch (hdr->type) {
438 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
439         case IPV6_SRCRT_TYPE_2:
440                 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
441                                      (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
442                                      IPPROTO_ROUTING) < 0) {
443                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
444                                          IPSTATS_MIB_INADDRERRORS);
445                         kfree_skb(skb);
446                         return -1;
447                 }
448                 if (!ipv6_chk_home_addr(&init_net, addr)) {
449                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
450                                          IPSTATS_MIB_INADDRERRORS);
451                         kfree_skb(skb);
452                         return -1;
453                 }
454                 break;
455 #endif
456         default:
457                 break;
458         }
459
460         if (ipv6_addr_is_multicast(addr)) {
461                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
462                                  IPSTATS_MIB_INADDRERRORS);
463                 kfree_skb(skb);
464                 return -1;
465         }
466
467         ipv6_addr_copy(&daddr, addr);
468         ipv6_addr_copy(addr, &ipv6_hdr(skb)->daddr);
469         ipv6_addr_copy(&ipv6_hdr(skb)->daddr, &daddr);
470
471         dst_release(xchg(&skb->dst, NULL));
472         ip6_route_input(skb);
473         if (skb->dst->error) {
474                 skb_push(skb, skb->data - skb_network_header(skb));
475                 dst_input(skb);
476                 return -1;
477         }
478
479         if (skb->dst->dev->flags&IFF_LOOPBACK) {
480                 if (ipv6_hdr(skb)->hop_limit <= 1) {
481                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
482                                          IPSTATS_MIB_INHDRERRORS);
483                         icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
484                                     0, skb->dev);
485                         kfree_skb(skb);
486                         return -1;
487                 }
488                 ipv6_hdr(skb)->hop_limit--;
489                 goto looped_back;
490         }
491
492         skb_push(skb, skb->data - skb_network_header(skb));
493         dst_input(skb);
494         return -1;
495
496 unknown_rh:
497         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
498         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
499                           (&hdr->type) - skb_network_header(skb));
500         return -1;
501 }
502
503 static struct inet6_protocol rthdr_protocol = {
504         .handler        =       ipv6_rthdr_rcv,
505         .flags          =       INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
506 };
507
508 static struct inet6_protocol destopt_protocol = {
509         .handler        =       ipv6_destopt_rcv,
510         .flags          =       INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
511 };
512
513 static struct inet6_protocol nodata_protocol = {
514         .handler        =       dst_discard,
515         .flags          =       INET6_PROTO_NOPOLICY,
516 };
517
518 int __init ipv6_exthdrs_init(void)
519 {
520         int ret;
521
522         ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
523         if (ret)
524                 goto out;
525
526         ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
527         if (ret)
528                 goto out_rthdr;
529
530         ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
531         if (ret)
532                 goto out_destopt;
533
534 out:
535         return ret;
536 out_rthdr:
537         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
538 out_destopt:
539         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
540         goto out;
541 };
542
543 void ipv6_exthdrs_exit(void)
544 {
545         inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
546         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
547         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
548 }
549
550 /**********************************
551   Hop-by-hop options.
552  **********************************/
553
554 /*
555  * Note: we cannot rely on skb->dst before we assign it in ip6_route_input().
556  */
557 static inline struct inet6_dev *ipv6_skb_idev(struct sk_buff *skb)
558 {
559         return skb->dst ? ip6_dst_idev(skb->dst) : __in6_dev_get(skb->dev);
560 }
561
562 /* Router Alert as of RFC 2711 */
563
564 static int ipv6_hop_ra(struct sk_buff *skb, int optoff)
565 {
566         const unsigned char *nh = skb_network_header(skb);
567
568         if (nh[optoff + 1] == 2) {
569                 IP6CB(skb)->ra = optoff;
570                 return 1;
571         }
572         LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_ra: wrong RA length %d\n",
573                        nh[optoff + 1]);
574         kfree_skb(skb);
575         return 0;
576 }
577
578 /* Jumbo payload */
579
580 static int ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
581 {
582         const unsigned char *nh = skb_network_header(skb);
583         u32 pkt_len;
584
585         if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
586                 LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
587                                nh[optoff+1]);
588                 IP6_INC_STATS_BH(ipv6_skb_idev(skb),
589                                  IPSTATS_MIB_INHDRERRORS);
590                 goto drop;
591         }
592
593         pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
594         if (pkt_len <= IPV6_MAXPLEN) {
595                 IP6_INC_STATS_BH(ipv6_skb_idev(skb), IPSTATS_MIB_INHDRERRORS);
596                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
597                 return 0;
598         }
599         if (ipv6_hdr(skb)->payload_len) {
600                 IP6_INC_STATS_BH(ipv6_skb_idev(skb), IPSTATS_MIB_INHDRERRORS);
601                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
602                 return 0;
603         }
604
605         if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
606                 IP6_INC_STATS_BH(ipv6_skb_idev(skb), IPSTATS_MIB_INTRUNCATEDPKTS);
607                 goto drop;
608         }
609
610         if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
611                 goto drop;
612
613         return 1;
614
615 drop:
616         kfree_skb(skb);
617         return 0;
618 }
619
620 static struct tlvtype_proc tlvprochopopt_lst[] = {
621         {
622                 .type   = IPV6_TLV_ROUTERALERT,
623                 .func   = ipv6_hop_ra,
624         },
625         {
626                 .type   = IPV6_TLV_JUMBO,
627                 .func   = ipv6_hop_jumbo,
628         },
629         { -1, }
630 };
631
632 int ipv6_parse_hopopts(struct sk_buff *skb)
633 {
634         struct inet6_skb_parm *opt = IP6CB(skb);
635
636         /*
637          * skb_network_header(skb) is equal to skb->data, and
638          * skb_network_header_len(skb) is always equal to
639          * sizeof(struct ipv6hdr) by definition of
640          * hop-by-hop options.
641          */
642         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
643             !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
644                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
645                 kfree_skb(skb);
646                 return -1;
647         }
648
649         opt->hop = sizeof(struct ipv6hdr);
650         if (ip6_parse_tlv(tlvprochopopt_lst, skb)) {
651                 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
652                 opt = IP6CB(skb);
653                 opt->nhoff = sizeof(struct ipv6hdr);
654                 return 1;
655         }
656         return -1;
657 }
658
659 /*
660  *      Creating outbound headers.
661  *
662  *      "build" functions work when skb is filled from head to tail (datagram)
663  *      "push"  functions work when headers are added from tail to head (tcp)
664  *
665  *      In both cases we assume, that caller reserved enough room
666  *      for headers.
667  */
668
669 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
670                             struct ipv6_rt_hdr *opt,
671                             struct in6_addr **addr_p)
672 {
673         struct rt0_hdr *phdr, *ihdr;
674         int hops;
675
676         ihdr = (struct rt0_hdr *) opt;
677
678         phdr = (struct rt0_hdr *) skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
679         memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
680
681         hops = ihdr->rt_hdr.hdrlen >> 1;
682
683         if (hops > 1)
684                 memcpy(phdr->addr, ihdr->addr + 1,
685                        (hops - 1) * sizeof(struct in6_addr));
686
687         ipv6_addr_copy(phdr->addr + (hops - 1), *addr_p);
688         *addr_p = ihdr->addr;
689
690         phdr->rt_hdr.nexthdr = *proto;
691         *proto = NEXTHDR_ROUTING;
692 }
693
694 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
695 {
696         struct ipv6_opt_hdr *h = (struct ipv6_opt_hdr *)skb_push(skb, ipv6_optlen(opt));
697
698         memcpy(h, opt, ipv6_optlen(opt));
699         h->nexthdr = *proto;
700         *proto = type;
701 }
702
703 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
704                           u8 *proto,
705                           struct in6_addr **daddr)
706 {
707         if (opt->srcrt) {
708                 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr);
709                 /*
710                  * IPV6_RTHDRDSTOPTS is ignored
711                  * unless IPV6_RTHDR is set (RFC3542).
712                  */
713                 if (opt->dst0opt)
714                         ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
715         }
716         if (opt->hopopt)
717                 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
718 }
719
720 EXPORT_SYMBOL(ipv6_push_nfrag_opts);
721
722 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
723 {
724         if (opt->dst1opt)
725                 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
726 }
727
728 struct ipv6_txoptions *
729 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
730 {
731         struct ipv6_txoptions *opt2;
732
733         opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
734         if (opt2) {
735                 long dif = (char*)opt2 - (char*)opt;
736                 memcpy(opt2, opt, opt->tot_len);
737                 if (opt2->hopopt)
738                         *((char**)&opt2->hopopt) += dif;
739                 if (opt2->dst0opt)
740                         *((char**)&opt2->dst0opt) += dif;
741                 if (opt2->dst1opt)
742                         *((char**)&opt2->dst1opt) += dif;
743                 if (opt2->srcrt)
744                         *((char**)&opt2->srcrt) += dif;
745         }
746         return opt2;
747 }
748
749 EXPORT_SYMBOL_GPL(ipv6_dup_options);
750
751 static int ipv6_renew_option(void *ohdr,
752                              struct ipv6_opt_hdr __user *newopt, int newoptlen,
753                              int inherit,
754                              struct ipv6_opt_hdr **hdr,
755                              char **p)
756 {
757         if (inherit) {
758                 if (ohdr) {
759                         memcpy(*p, ohdr, ipv6_optlen((struct ipv6_opt_hdr *)ohdr));
760                         *hdr = (struct ipv6_opt_hdr *)*p;
761                         *p += CMSG_ALIGN(ipv6_optlen(*(struct ipv6_opt_hdr **)hdr));
762                 }
763         } else {
764                 if (newopt) {
765                         if (copy_from_user(*p, newopt, newoptlen))
766                                 return -EFAULT;
767                         *hdr = (struct ipv6_opt_hdr *)*p;
768                         if (ipv6_optlen(*(struct ipv6_opt_hdr **)hdr) > newoptlen)
769                                 return -EINVAL;
770                         *p += CMSG_ALIGN(newoptlen);
771                 }
772         }
773         return 0;
774 }
775
776 struct ipv6_txoptions *
777 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
778                    int newtype,
779                    struct ipv6_opt_hdr __user *newopt, int newoptlen)
780 {
781         int tot_len = 0;
782         char *p;
783         struct ipv6_txoptions *opt2;
784         int err;
785
786         if (opt) {
787                 if (newtype != IPV6_HOPOPTS && opt->hopopt)
788                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
789                 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
790                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
791                 if (newtype != IPV6_RTHDR && opt->srcrt)
792                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
793                 if (newtype != IPV6_DSTOPTS && opt->dst1opt)
794                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
795         }
796
797         if (newopt && newoptlen)
798                 tot_len += CMSG_ALIGN(newoptlen);
799
800         if (!tot_len)
801                 return NULL;
802
803         tot_len += sizeof(*opt2);
804         opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
805         if (!opt2)
806                 return ERR_PTR(-ENOBUFS);
807
808         memset(opt2, 0, tot_len);
809
810         opt2->tot_len = tot_len;
811         p = (char *)(opt2 + 1);
812
813         err = ipv6_renew_option(opt ? opt->hopopt : NULL, newopt, newoptlen,
814                                 newtype != IPV6_HOPOPTS,
815                                 &opt2->hopopt, &p);
816         if (err)
817                 goto out;
818
819         err = ipv6_renew_option(opt ? opt->dst0opt : NULL, newopt, newoptlen,
820                                 newtype != IPV6_RTHDRDSTOPTS,
821                                 &opt2->dst0opt, &p);
822         if (err)
823                 goto out;
824
825         err = ipv6_renew_option(opt ? opt->srcrt : NULL, newopt, newoptlen,
826                                 newtype != IPV6_RTHDR,
827                                 (struct ipv6_opt_hdr **)&opt2->srcrt, &p);
828         if (err)
829                 goto out;
830
831         err = ipv6_renew_option(opt ? opt->dst1opt : NULL, newopt, newoptlen,
832                                 newtype != IPV6_DSTOPTS,
833                                 &opt2->dst1opt, &p);
834         if (err)
835                 goto out;
836
837         opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
838                           (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
839                           (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
840         opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
841
842         return opt2;
843 out:
844         sock_kfree_s(sk, opt2, opt2->tot_len);
845         return ERR_PTR(err);
846 }
847
848 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
849                                           struct ipv6_txoptions *opt)
850 {
851         /*
852          * ignore the dest before srcrt unless srcrt is being included.
853          * --yoshfuji
854          */
855         if (opt && opt->dst0opt && !opt->srcrt) {
856                 if (opt_space != opt) {
857                         memcpy(opt_space, opt, sizeof(*opt_space));
858                         opt = opt_space;
859                 }
860                 opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
861                 opt->dst0opt = NULL;
862         }
863
864         return opt;
865 }
866