ipv6: When we droped a packet, we should return NET_RX_DROP instead of 0
[linux-2.6.git] / net / ipv6 / exthdrs.c
1 /*
2  *      Extension Header handling for IPv6
3  *      Linux INET6 implementation
4  *
5  *      Authors:
6  *      Pedro Roque             <roque@di.fc.ul.pt>
7  *      Andi Kleen              <ak@muc.de>
8  *      Alexey Kuznetsov        <kuznet@ms2.inr.ac.ru>
9  *
10  *      This program is free software; you can redistribute it and/or
11  *      modify it under the terms of the GNU General Public License
12  *      as published by the Free Software Foundation; either version
13  *      2 of the License, or (at your option) any later version.
14  */
15
16 /* Changes:
17  *      yoshfuji                : ensure not to overrun while parsing
18  *                                tlv options.
19  *      Mitsuru KANDA @USAGI and: Remove ipv6_parse_exthdrs().
20  *      YOSHIFUJI Hideaki @USAGI  Register inbound extension header
21  *                                handlers as inet6_protocol{}.
22  */
23
24 #include <linux/errno.h>
25 #include <linux/types.h>
26 #include <linux/socket.h>
27 #include <linux/sockios.h>
28 #include <linux/net.h>
29 #include <linux/netdevice.h>
30 #include <linux/in6.h>
31 #include <linux/icmpv6.h>
32
33 #include <net/dst.h>
34 #include <net/sock.h>
35 #include <net/snmp.h>
36
37 #include <net/ipv6.h>
38 #include <net/protocol.h>
39 #include <net/transp_v6.h>
40 #include <net/rawv6.h>
41 #include <net/ndisc.h>
42 #include <net/ip6_route.h>
43 #include <net/addrconf.h>
44 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
45 #include <net/xfrm.h>
46 #endif
47
48 #include <asm/uaccess.h>
49
50 int ipv6_find_tlv(struct sk_buff *skb, int offset, int type)
51 {
52         const unsigned char *nh = skb_network_header(skb);
53         int packet_len = skb->tail - skb->network_header;
54         struct ipv6_opt_hdr *hdr;
55         int len;
56
57         if (offset + 2 > packet_len)
58                 goto bad;
59         hdr = (struct ipv6_opt_hdr *)(nh + offset);
60         len = ((hdr->hdrlen + 1) << 3);
61
62         if (offset + len > packet_len)
63                 goto bad;
64
65         offset += 2;
66         len -= 2;
67
68         while (len > 0) {
69                 int opttype = nh[offset];
70                 int optlen;
71
72                 if (opttype == type)
73                         return offset;
74
75                 switch (opttype) {
76                 case IPV6_TLV_PAD0:
77                         optlen = 1;
78                         break;
79                 default:
80                         optlen = nh[offset + 1] + 2;
81                         if (optlen > len)
82                                 goto bad;
83                         break;
84                 }
85                 offset += optlen;
86                 len -= optlen;
87         }
88         /* not_found */
89  bad:
90         return -1;
91 }
92 EXPORT_SYMBOL_GPL(ipv6_find_tlv);
93
94 /*
95  *      Parsing tlv encoded headers.
96  *
97  *      Parsing function "func" returns 1, if parsing succeed
98  *      and 0, if it failed.
99  *      It MUST NOT touch skb->h.
100  */
101
102 struct tlvtype_proc {
103         int     type;
104         int     (*func)(struct sk_buff *skb, int offset);
105 };
106
107 /*********************
108   Generic functions
109  *********************/
110
111 /* An unknown option is detected, decide what to do */
112
113 static int ip6_tlvopt_unknown(struct sk_buff *skb, int optoff)
114 {
115         switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) {
116         case 0: /* ignore */
117                 return 1;
118
119         case 1: /* drop packet */
120                 break;
121
122         case 3: /* Send ICMP if not a multicast address and drop packet */
123                 /* Actually, it is redundant check. icmp_send
124                    will recheck in any case.
125                  */
126                 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr))
127                         break;
128         case 2: /* send ICMP PARM PROB regardless and drop packet */
129                 icmpv6_param_prob(skb, ICMPV6_UNK_OPTION, optoff);
130                 return 0;
131         }
132
133         kfree_skb(skb);
134         return 0;
135 }
136
137 /* Parse tlv encoded option header (hop-by-hop or destination) */
138
139 static int ip6_parse_tlv(struct tlvtype_proc *procs, struct sk_buff *skb)
140 {
141         struct tlvtype_proc *curr;
142         const unsigned char *nh = skb_network_header(skb);
143         int off = skb_network_header_len(skb);
144         int len = (skb_transport_header(skb)[1] + 1) << 3;
145
146         if (skb_transport_offset(skb) + len > skb_headlen(skb))
147                 goto bad;
148
149         off += 2;
150         len -= 2;
151
152         while (len > 0) {
153                 int optlen = nh[off + 1] + 2;
154
155                 switch (nh[off]) {
156                 case IPV6_TLV_PAD0:
157                         optlen = 1;
158                         break;
159
160                 case IPV6_TLV_PADN:
161                         break;
162
163                 default: /* Other TLV code so scan list */
164                         if (optlen > len)
165                                 goto bad;
166                         for (curr=procs; curr->type >= 0; curr++) {
167                                 if (curr->type == nh[off]) {
168                                         /* type specific length/alignment
169                                            checks will be performed in the
170                                            func(). */
171                                         if (curr->func(skb, off) == 0)
172                                                 return 0;
173                                         break;
174                                 }
175                         }
176                         if (curr->type < 0) {
177                                 if (ip6_tlvopt_unknown(skb, off) == 0)
178                                         return 0;
179                         }
180                         break;
181                 }
182                 off += optlen;
183                 len -= optlen;
184         }
185         if (len == 0)
186                 return 1;
187 bad:
188         kfree_skb(skb);
189         return 0;
190 }
191
192 /*****************************
193   Destination options header.
194  *****************************/
195
196 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
197 static int ipv6_dest_hao(struct sk_buff *skb, int optoff)
198 {
199         struct ipv6_destopt_hao *hao;
200         struct inet6_skb_parm *opt = IP6CB(skb);
201         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
202         struct in6_addr tmp_addr;
203         int ret;
204
205         if (opt->dsthao) {
206                 LIMIT_NETDEBUG(KERN_DEBUG "hao duplicated\n");
207                 goto discard;
208         }
209         opt->dsthao = opt->dst1;
210         opt->dst1 = 0;
211
212         hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff);
213
214         if (hao->length != 16) {
215                 LIMIT_NETDEBUG(
216                         KERN_DEBUG "hao invalid option length = %d\n", hao->length);
217                 goto discard;
218         }
219
220         if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) {
221                 LIMIT_NETDEBUG(
222                         KERN_DEBUG "hao is not an unicast addr: " NIP6_FMT "\n", NIP6(hao->addr));
223                 goto discard;
224         }
225
226         ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr,
227                                (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS);
228         if (unlikely(ret < 0))
229                 goto discard;
230
231         if (skb_cloned(skb)) {
232                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
233                         goto discard;
234
235                 /* update all variable using below by copied skbuff */
236                 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) +
237                                                   optoff);
238                 ipv6h = ipv6_hdr(skb);
239         }
240
241         if (skb->ip_summed == CHECKSUM_COMPLETE)
242                 skb->ip_summed = CHECKSUM_NONE;
243
244         ipv6_addr_copy(&tmp_addr, &ipv6h->saddr);
245         ipv6_addr_copy(&ipv6h->saddr, &hao->addr);
246         ipv6_addr_copy(&hao->addr, &tmp_addr);
247
248         if (skb->tstamp.tv64 == 0)
249                 __net_timestamp(skb);
250
251         return 1;
252
253  discard:
254         kfree_skb(skb);
255         return 0;
256 }
257 #endif
258
259 static struct tlvtype_proc tlvprocdestopt_lst[] = {
260 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
261         {
262                 .type   = IPV6_TLV_HAO,
263                 .func   = ipv6_dest_hao,
264         },
265 #endif
266         {-1,                    NULL}
267 };
268
269 static int ipv6_destopt_rcv(struct sk_buff *skb)
270 {
271         struct inet6_skb_parm *opt = IP6CB(skb);
272 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
273         __u16 dstbuf;
274 #endif
275         struct dst_entry *dst;
276
277         if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
278             !pskb_may_pull(skb, (skb_transport_offset(skb) +
279                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
280                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
281                                  IPSTATS_MIB_INHDRERRORS);
282                 kfree_skb(skb);
283                 return -1;
284         }
285
286         opt->lastopt = opt->dst1 = skb_network_header_len(skb);
287 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
288         dstbuf = opt->dst1;
289 #endif
290
291         dst = dst_clone(skb->dst);
292         if (ip6_parse_tlv(tlvprocdestopt_lst, skb)) {
293                 dst_release(dst);
294                 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
295                 opt = IP6CB(skb);
296 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
297                 opt->nhoff = dstbuf;
298 #else
299                 opt->nhoff = opt->dst1;
300 #endif
301                 return 1;
302         }
303
304         IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS);
305         dst_release(dst);
306         return -1;
307 }
308
309 /********************************
310   Routing header.
311  ********************************/
312
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         int accept_source_route = dev_net(skb->dev)->ipv6.devconf_all->accept_source_route;
323
324         idev = in6_dev_get(skb->dev);
325         if (idev) {
326                 if (accept_source_route > idev->cnf.accept_source_route)
327                         accept_source_route = idev->cnf.accept_source_route;
328                 in6_dev_put(idev);
329         }
330
331         if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
332             !pskb_may_pull(skb, (skb_transport_offset(skb) +
333                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
334                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
335                                  IPSTATS_MIB_INHDRERRORS);
336                 kfree_skb(skb);
337                 return -1;
338         }
339
340         hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
341
342         if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
343             skb->pkt_type != PACKET_HOST) {
344                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
345                                  IPSTATS_MIB_INADDRERRORS);
346                 kfree_skb(skb);
347                 return -1;
348         }
349
350 looped_back:
351         if (hdr->segments_left == 0) {
352                 switch (hdr->type) {
353 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
354                 case IPV6_SRCRT_TYPE_2:
355                         /* Silently discard type 2 header unless it was
356                          * processed by own
357                          */
358                         if (!addr) {
359                                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
360                                                  IPSTATS_MIB_INADDRERRORS);
361                                 kfree_skb(skb);
362                                 return -1;
363                         }
364                         break;
365 #endif
366                 default:
367                         break;
368                 }
369
370                 opt->lastopt = opt->srcrt = skb_network_header_len(skb);
371                 skb->transport_header += (hdr->hdrlen + 1) << 3;
372                 opt->dst0 = opt->dst1;
373                 opt->dst1 = 0;
374                 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
375                 return 1;
376         }
377
378         switch (hdr->type) {
379 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
380         case IPV6_SRCRT_TYPE_2:
381                 if (accept_source_route < 0)
382                         goto unknown_rh;
383                 /* Silently discard invalid RTH type 2 */
384                 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
385                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
386                                          IPSTATS_MIB_INHDRERRORS);
387                         kfree_skb(skb);
388                         return -1;
389                 }
390                 break;
391 #endif
392         default:
393                 goto unknown_rh;
394         }
395
396         /*
397          *      This is the routing header forwarding algorithm from
398          *      RFC 2460, page 16.
399          */
400
401         n = hdr->hdrlen >> 1;
402
403         if (hdr->segments_left > n) {
404                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
405                                  IPSTATS_MIB_INHDRERRORS);
406                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
407                                   ((&hdr->segments_left) -
408                                    skb_network_header(skb)));
409                 return -1;
410         }
411
412         /* We are about to mangle packet header. Be careful!
413            Do not damage packets queued somewhere.
414          */
415         if (skb_cloned(skb)) {
416                 /* the copy is a forwarded packet */
417                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
418                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
419                                          IPSTATS_MIB_OUTDISCARDS);
420                         kfree_skb(skb);
421                         return -1;
422                 }
423                 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
424         }
425
426         if (skb->ip_summed == CHECKSUM_COMPLETE)
427                 skb->ip_summed = CHECKSUM_NONE;
428
429         i = n - --hdr->segments_left;
430
431         rthdr = (struct rt0_hdr *) hdr;
432         addr = rthdr->addr;
433         addr += i - 1;
434
435         switch (hdr->type) {
436 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
437         case IPV6_SRCRT_TYPE_2:
438                 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
439                                      (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
440                                      IPPROTO_ROUTING) < 0) {
441                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
442                                          IPSTATS_MIB_INADDRERRORS);
443                         kfree_skb(skb);
444                         return -1;
445                 }
446                 if (!ipv6_chk_home_addr(dev_net(skb->dst->dev), addr)) {
447                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
448                                          IPSTATS_MIB_INADDRERRORS);
449                         kfree_skb(skb);
450                         return -1;
451                 }
452                 break;
453 #endif
454         default:
455                 break;
456         }
457
458         if (ipv6_addr_is_multicast(addr)) {
459                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
460                                  IPSTATS_MIB_INADDRERRORS);
461                 kfree_skb(skb);
462                 return -1;
463         }
464
465         ipv6_addr_copy(&daddr, addr);
466         ipv6_addr_copy(addr, &ipv6_hdr(skb)->daddr);
467         ipv6_addr_copy(&ipv6_hdr(skb)->daddr, &daddr);
468
469         dst_release(xchg(&skb->dst, NULL));
470         ip6_route_input(skb);
471         if (skb->dst->error) {
472                 skb_push(skb, skb->data - skb_network_header(skb));
473                 dst_input(skb);
474                 return -1;
475         }
476
477         if (skb->dst->dev->flags&IFF_LOOPBACK) {
478                 if (ipv6_hdr(skb)->hop_limit <= 1) {
479                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
480                                          IPSTATS_MIB_INHDRERRORS);
481                         icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
482                                     0, skb->dev);
483                         kfree_skb(skb);
484                         return -1;
485                 }
486                 ipv6_hdr(skb)->hop_limit--;
487                 goto looped_back;
488         }
489
490         skb_push(skb, skb->data - skb_network_header(skb));
491         dst_input(skb);
492         return -1;
493
494 unknown_rh:
495         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
496         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
497                           (&hdr->type) - skb_network_header(skb));
498         return -1;
499 }
500
501 static struct inet6_protocol rthdr_protocol = {
502         .handler        =       ipv6_rthdr_rcv,
503         .flags          =       INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
504 };
505
506 static struct inet6_protocol destopt_protocol = {
507         .handler        =       ipv6_destopt_rcv,
508         .flags          =       INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
509 };
510
511 static struct inet6_protocol nodata_protocol = {
512         .handler        =       dst_discard,
513         .flags          =       INET6_PROTO_NOPOLICY,
514 };
515
516 int __init ipv6_exthdrs_init(void)
517 {
518         int ret;
519
520         ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
521         if (ret)
522                 goto out;
523
524         ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
525         if (ret)
526                 goto out_rthdr;
527
528         ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
529         if (ret)
530                 goto out_destopt;
531
532 out:
533         return ret;
534 out_rthdr:
535         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
536 out_destopt:
537         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
538         goto out;
539 };
540
541 void ipv6_exthdrs_exit(void)
542 {
543         inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
544         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
545         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
546 }
547
548 /**********************************
549   Hop-by-hop options.
550  **********************************/
551
552 /*
553  * Note: we cannot rely on skb->dst before we assign it in ip6_route_input().
554  */
555 static inline struct inet6_dev *ipv6_skb_idev(struct sk_buff *skb)
556 {
557         return skb->dst ? ip6_dst_idev(skb->dst) : __in6_dev_get(skb->dev);
558 }
559
560 /* Router Alert as of RFC 2711 */
561
562 static int ipv6_hop_ra(struct sk_buff *skb, int optoff)
563 {
564         const unsigned char *nh = skb_network_header(skb);
565
566         if (nh[optoff + 1] == 2) {
567                 IP6CB(skb)->ra = optoff;
568                 return 1;
569         }
570         LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_ra: wrong RA length %d\n",
571                        nh[optoff + 1]);
572         kfree_skb(skb);
573         return 0;
574 }
575
576 /* Jumbo payload */
577
578 static int ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
579 {
580         const unsigned char *nh = skb_network_header(skb);
581         u32 pkt_len;
582
583         if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
584                 LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
585                                nh[optoff+1]);
586                 IP6_INC_STATS_BH(ipv6_skb_idev(skb),
587                                  IPSTATS_MIB_INHDRERRORS);
588                 goto drop;
589         }
590
591         pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
592         if (pkt_len <= IPV6_MAXPLEN) {
593                 IP6_INC_STATS_BH(ipv6_skb_idev(skb), IPSTATS_MIB_INHDRERRORS);
594                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
595                 return 0;
596         }
597         if (ipv6_hdr(skb)->payload_len) {
598                 IP6_INC_STATS_BH(ipv6_skb_idev(skb), IPSTATS_MIB_INHDRERRORS);
599                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
600                 return 0;
601         }
602
603         if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
604                 IP6_INC_STATS_BH(ipv6_skb_idev(skb), IPSTATS_MIB_INTRUNCATEDPKTS);
605                 goto drop;
606         }
607
608         if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
609                 goto drop;
610
611         return 1;
612
613 drop:
614         kfree_skb(skb);
615         return 0;
616 }
617
618 static struct tlvtype_proc tlvprochopopt_lst[] = {
619         {
620                 .type   = IPV6_TLV_ROUTERALERT,
621                 .func   = ipv6_hop_ra,
622         },
623         {
624                 .type   = IPV6_TLV_JUMBO,
625                 .func   = ipv6_hop_jumbo,
626         },
627         { -1, }
628 };
629
630 int ipv6_parse_hopopts(struct sk_buff *skb)
631 {
632         struct inet6_skb_parm *opt = IP6CB(skb);
633
634         /*
635          * skb_network_header(skb) is equal to skb->data, and
636          * skb_network_header_len(skb) is always equal to
637          * sizeof(struct ipv6hdr) by definition of
638          * hop-by-hop options.
639          */
640         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
641             !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
642                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
643                 kfree_skb(skb);
644                 return -1;
645         }
646
647         opt->hop = sizeof(struct ipv6hdr);
648         if (ip6_parse_tlv(tlvprochopopt_lst, skb)) {
649                 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
650                 opt = IP6CB(skb);
651                 opt->nhoff = sizeof(struct ipv6hdr);
652                 return 1;
653         }
654         return -1;
655 }
656
657 /*
658  *      Creating outbound headers.
659  *
660  *      "build" functions work when skb is filled from head to tail (datagram)
661  *      "push"  functions work when headers are added from tail to head (tcp)
662  *
663  *      In both cases we assume, that caller reserved enough room
664  *      for headers.
665  */
666
667 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
668                             struct ipv6_rt_hdr *opt,
669                             struct in6_addr **addr_p)
670 {
671         struct rt0_hdr *phdr, *ihdr;
672         int hops;
673
674         ihdr = (struct rt0_hdr *) opt;
675
676         phdr = (struct rt0_hdr *) skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
677         memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
678
679         hops = ihdr->rt_hdr.hdrlen >> 1;
680
681         if (hops > 1)
682                 memcpy(phdr->addr, ihdr->addr + 1,
683                        (hops - 1) * sizeof(struct in6_addr));
684
685         ipv6_addr_copy(phdr->addr + (hops - 1), *addr_p);
686         *addr_p = ihdr->addr;
687
688         phdr->rt_hdr.nexthdr = *proto;
689         *proto = NEXTHDR_ROUTING;
690 }
691
692 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
693 {
694         struct ipv6_opt_hdr *h = (struct ipv6_opt_hdr *)skb_push(skb, ipv6_optlen(opt));
695
696         memcpy(h, opt, ipv6_optlen(opt));
697         h->nexthdr = *proto;
698         *proto = type;
699 }
700
701 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
702                           u8 *proto,
703                           struct in6_addr **daddr)
704 {
705         if (opt->srcrt) {
706                 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr);
707                 /*
708                  * IPV6_RTHDRDSTOPTS is ignored
709                  * unless IPV6_RTHDR is set (RFC3542).
710                  */
711                 if (opt->dst0opt)
712                         ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
713         }
714         if (opt->hopopt)
715                 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
716 }
717
718 EXPORT_SYMBOL(ipv6_push_nfrag_opts);
719
720 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
721 {
722         if (opt->dst1opt)
723                 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
724 }
725
726 struct ipv6_txoptions *
727 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
728 {
729         struct ipv6_txoptions *opt2;
730
731         opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
732         if (opt2) {
733                 long dif = (char*)opt2 - (char*)opt;
734                 memcpy(opt2, opt, opt->tot_len);
735                 if (opt2->hopopt)
736                         *((char**)&opt2->hopopt) += dif;
737                 if (opt2->dst0opt)
738                         *((char**)&opt2->dst0opt) += dif;
739                 if (opt2->dst1opt)
740                         *((char**)&opt2->dst1opt) += dif;
741                 if (opt2->srcrt)
742                         *((char**)&opt2->srcrt) += dif;
743         }
744         return opt2;
745 }
746
747 EXPORT_SYMBOL_GPL(ipv6_dup_options);
748
749 static int ipv6_renew_option(void *ohdr,
750                              struct ipv6_opt_hdr __user *newopt, int newoptlen,
751                              int inherit,
752                              struct ipv6_opt_hdr **hdr,
753                              char **p)
754 {
755         if (inherit) {
756                 if (ohdr) {
757                         memcpy(*p, ohdr, ipv6_optlen((struct ipv6_opt_hdr *)ohdr));
758                         *hdr = (struct ipv6_opt_hdr *)*p;
759                         *p += CMSG_ALIGN(ipv6_optlen(*(struct ipv6_opt_hdr **)hdr));
760                 }
761         } else {
762                 if (newopt) {
763                         if (copy_from_user(*p, newopt, newoptlen))
764                                 return -EFAULT;
765                         *hdr = (struct ipv6_opt_hdr *)*p;
766                         if (ipv6_optlen(*(struct ipv6_opt_hdr **)hdr) > newoptlen)
767                                 return -EINVAL;
768                         *p += CMSG_ALIGN(newoptlen);
769                 }
770         }
771         return 0;
772 }
773
774 struct ipv6_txoptions *
775 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
776                    int newtype,
777                    struct ipv6_opt_hdr __user *newopt, int newoptlen)
778 {
779         int tot_len = 0;
780         char *p;
781         struct ipv6_txoptions *opt2;
782         int err;
783
784         if (opt) {
785                 if (newtype != IPV6_HOPOPTS && opt->hopopt)
786                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
787                 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
788                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
789                 if (newtype != IPV6_RTHDR && opt->srcrt)
790                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
791                 if (newtype != IPV6_DSTOPTS && opt->dst1opt)
792                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
793         }
794
795         if (newopt && newoptlen)
796                 tot_len += CMSG_ALIGN(newoptlen);
797
798         if (!tot_len)
799                 return NULL;
800
801         tot_len += sizeof(*opt2);
802         opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
803         if (!opt2)
804                 return ERR_PTR(-ENOBUFS);
805
806         memset(opt2, 0, tot_len);
807
808         opt2->tot_len = tot_len;
809         p = (char *)(opt2 + 1);
810
811         err = ipv6_renew_option(opt ? opt->hopopt : NULL, newopt, newoptlen,
812                                 newtype != IPV6_HOPOPTS,
813                                 &opt2->hopopt, &p);
814         if (err)
815                 goto out;
816
817         err = ipv6_renew_option(opt ? opt->dst0opt : NULL, newopt, newoptlen,
818                                 newtype != IPV6_RTHDRDSTOPTS,
819                                 &opt2->dst0opt, &p);
820         if (err)
821                 goto out;
822
823         err = ipv6_renew_option(opt ? opt->srcrt : NULL, newopt, newoptlen,
824                                 newtype != IPV6_RTHDR,
825                                 (struct ipv6_opt_hdr **)&opt2->srcrt, &p);
826         if (err)
827                 goto out;
828
829         err = ipv6_renew_option(opt ? opt->dst1opt : NULL, newopt, newoptlen,
830                                 newtype != IPV6_DSTOPTS,
831                                 &opt2->dst1opt, &p);
832         if (err)
833                 goto out;
834
835         opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
836                           (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
837                           (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
838         opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
839
840         return opt2;
841 out:
842         sock_kfree_s(sk, opt2, opt2->tot_len);
843         return ERR_PTR(err);
844 }
845
846 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
847                                           struct ipv6_txoptions *opt)
848 {
849         /*
850          * ignore the dest before srcrt unless srcrt is being included.
851          * --yoshfuji
852          */
853         if (opt && opt->dst0opt && !opt->srcrt) {
854                 if (opt_space != opt) {
855                         memcpy(opt_space, opt, sizeof(*opt_space));
856                         opt = opt_space;
857                 }
858                 opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
859                 opt->dst0opt = NULL;
860         }
861
862         return opt;
863 }
864