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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/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 | #ifdef CONFIG_IPV6_MIP6 | |
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 - nh; | |
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 | ||
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 **skbp, 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 **skbp, int optoff) | |
114 | { | |
115 | struct sk_buff *skb = *skbp; | |
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 **skbp) | |
142 | { | |
143 | struct sk_buff *skb = *skbp; | |
144 | struct tlvtype_proc *curr; | |
145 | const unsigned char *nh = skb_network_header(skb); | |
146 | int off = skb->h.raw - skb->nh.raw; | |
147 | int len = (skb_transport_header(skb)[1] + 1) << 3; | |
148 | ||
149 | if (skb_transport_offset(skb) + len > skb_headlen(skb)) | |
150 | goto bad; | |
151 | ||
152 | off += 2; | |
153 | len -= 2; | |
154 | ||
155 | while (len > 0) { | |
156 | int optlen = nh[off + 1] + 2; | |
157 | ||
158 | switch (nh[off]) { | |
159 | case IPV6_TLV_PAD0: | |
160 | optlen = 1; | |
161 | break; | |
162 | ||
163 | case IPV6_TLV_PADN: | |
164 | break; | |
165 | ||
166 | default: /* Other TLV code so scan list */ | |
167 | if (optlen > len) | |
168 | goto bad; | |
169 | for (curr=procs; curr->type >= 0; curr++) { | |
170 | if (curr->type == nh[off]) { | |
171 | /* type specific length/alignment | |
172 | checks will be performed in the | |
173 | func(). */ | |
174 | if (curr->func(skbp, off) == 0) | |
175 | return 0; | |
176 | break; | |
177 | } | |
178 | } | |
179 | if (curr->type < 0) { | |
180 | if (ip6_tlvopt_unknown(skbp, off) == 0) | |
181 | return 0; | |
182 | } | |
183 | break; | |
184 | } | |
185 | off += optlen; | |
186 | len -= optlen; | |
187 | } | |
188 | if (len == 0) | |
189 | return 1; | |
190 | bad: | |
191 | kfree_skb(skb); | |
192 | return 0; | |
193 | } | |
194 | ||
195 | /***************************** | |
196 | Destination options header. | |
197 | *****************************/ | |
198 | ||
199 | #ifdef CONFIG_IPV6_MIP6 | |
200 | static int ipv6_dest_hao(struct sk_buff **skbp, int optoff) | |
201 | { | |
202 | struct sk_buff *skb = *skbp; | |
203 | struct ipv6_destopt_hao *hao; | |
204 | struct inet6_skb_parm *opt = IP6CB(skb); | |
205 | struct ipv6hdr *ipv6h = ipv6_hdr(skb); | |
206 | struct in6_addr tmp_addr; | |
207 | int ret; | |
208 | ||
209 | if (opt->dsthao) { | |
210 | LIMIT_NETDEBUG(KERN_DEBUG "hao duplicated\n"); | |
211 | goto discard; | |
212 | } | |
213 | opt->dsthao = opt->dst1; | |
214 | opt->dst1 = 0; | |
215 | ||
216 | hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff); | |
217 | ||
218 | if (hao->length != 16) { | |
219 | LIMIT_NETDEBUG( | |
220 | KERN_DEBUG "hao invalid option length = %d\n", hao->length); | |
221 | goto discard; | |
222 | } | |
223 | ||
224 | if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) { | |
225 | LIMIT_NETDEBUG( | |
226 | KERN_DEBUG "hao is not an unicast addr: " NIP6_FMT "\n", NIP6(hao->addr)); | |
227 | goto discard; | |
228 | } | |
229 | ||
230 | ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr, | |
231 | (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS); | |
232 | if (unlikely(ret < 0)) | |
233 | goto discard; | |
234 | ||
235 | if (skb_cloned(skb)) { | |
236 | struct sk_buff *skb2 = skb_copy(skb, GFP_ATOMIC); | |
237 | struct inet6_skb_parm *opt2; | |
238 | ||
239 | if (skb2 == NULL) | |
240 | goto discard; | |
241 | ||
242 | opt2 = IP6CB(skb2); | |
243 | memcpy(opt2, opt, sizeof(*opt2)); | |
244 | ||
245 | kfree_skb(skb); | |
246 | ||
247 | /* update all variable using below by copied skbuff */ | |
248 | *skbp = skb = skb2; | |
249 | hao = (struct ipv6_destopt_hao *)(skb_network_header(skb2) + | |
250 | optoff); | |
251 | ipv6h = ipv6_hdr(skb2); | |
252 | } | |
253 | ||
254 | if (skb->ip_summed == CHECKSUM_COMPLETE) | |
255 | skb->ip_summed = CHECKSUM_NONE; | |
256 | ||
257 | ipv6_addr_copy(&tmp_addr, &ipv6h->saddr); | |
258 | ipv6_addr_copy(&ipv6h->saddr, &hao->addr); | |
259 | ipv6_addr_copy(&hao->addr, &tmp_addr); | |
260 | ||
261 | if (skb->tstamp.tv64 == 0) | |
262 | __net_timestamp(skb); | |
263 | ||
264 | return 1; | |
265 | ||
266 | discard: | |
267 | kfree_skb(skb); | |
268 | return 0; | |
269 | } | |
270 | #endif | |
271 | ||
272 | static struct tlvtype_proc tlvprocdestopt_lst[] = { | |
273 | #ifdef CONFIG_IPV6_MIP6 | |
274 | { | |
275 | .type = IPV6_TLV_HAO, | |
276 | .func = ipv6_dest_hao, | |
277 | }, | |
278 | #endif | |
279 | {-1, NULL} | |
280 | }; | |
281 | ||
282 | static int ipv6_destopt_rcv(struct sk_buff **skbp) | |
283 | { | |
284 | struct sk_buff *skb = *skbp; | |
285 | struct inet6_skb_parm *opt = IP6CB(skb); | |
286 | #ifdef CONFIG_IPV6_MIP6 | |
287 | __u16 dstbuf; | |
288 | #endif | |
289 | struct dst_entry *dst; | |
290 | ||
291 | if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) || | |
292 | !pskb_may_pull(skb, (skb_transport_offset(skb) + | |
293 | ((skb_transport_header(skb)[1] + 1) << 3)))) { | |
294 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), | |
295 | IPSTATS_MIB_INHDRERRORS); | |
296 | kfree_skb(skb); | |
297 | return -1; | |
298 | } | |
299 | ||
300 | opt->lastopt = opt->dst1 = skb->h.raw - skb->nh.raw; | |
301 | #ifdef CONFIG_IPV6_MIP6 | |
302 | dstbuf = opt->dst1; | |
303 | #endif | |
304 | ||
305 | dst = dst_clone(skb->dst); | |
306 | if (ip6_parse_tlv(tlvprocdestopt_lst, skbp)) { | |
307 | dst_release(dst); | |
308 | skb = *skbp; | |
309 | skb->h.raw += (skb_transport_header(skb)[1] + 1) << 3; | |
310 | opt = IP6CB(skb); | |
311 | #ifdef CONFIG_IPV6_MIP6 | |
312 | opt->nhoff = dstbuf; | |
313 | #else | |
314 | opt->nhoff = opt->dst1; | |
315 | #endif | |
316 | return 1; | |
317 | } | |
318 | ||
319 | IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS); | |
320 | dst_release(dst); | |
321 | return -1; | |
322 | } | |
323 | ||
324 | static struct inet6_protocol destopt_protocol = { | |
325 | .handler = ipv6_destopt_rcv, | |
326 | .flags = INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR, | |
327 | }; | |
328 | ||
329 | void __init ipv6_destopt_init(void) | |
330 | { | |
331 | if (inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS) < 0) | |
332 | printk(KERN_ERR "ipv6_destopt_init: Could not register protocol\n"); | |
333 | } | |
334 | ||
335 | /******************************** | |
336 | NONE header. No data in packet. | |
337 | ********************************/ | |
338 | ||
339 | static int ipv6_nodata_rcv(struct sk_buff **skbp) | |
340 | { | |
341 | struct sk_buff *skb = *skbp; | |
342 | ||
343 | kfree_skb(skb); | |
344 | return 0; | |
345 | } | |
346 | ||
347 | static struct inet6_protocol nodata_protocol = { | |
348 | .handler = ipv6_nodata_rcv, | |
349 | .flags = INET6_PROTO_NOPOLICY, | |
350 | }; | |
351 | ||
352 | void __init ipv6_nodata_init(void) | |
353 | { | |
354 | if (inet6_add_protocol(&nodata_protocol, IPPROTO_NONE) < 0) | |
355 | printk(KERN_ERR "ipv6_nodata_init: Could not register protocol\n"); | |
356 | } | |
357 | ||
358 | /******************************** | |
359 | Routing header. | |
360 | ********************************/ | |
361 | ||
362 | static int ipv6_rthdr_rcv(struct sk_buff **skbp) | |
363 | { | |
364 | struct sk_buff *skb = *skbp; | |
365 | struct inet6_skb_parm *opt = IP6CB(skb); | |
366 | struct in6_addr *addr = NULL; | |
367 | struct in6_addr daddr; | |
368 | struct inet6_dev *idev; | |
369 | int n, i; | |
370 | struct ipv6_rt_hdr *hdr; | |
371 | struct rt0_hdr *rthdr; | |
372 | int accept_source_route = ipv6_devconf.accept_source_route; | |
373 | ||
374 | if (accept_source_route < 0 || | |
375 | ((idev = in6_dev_get(skb->dev)) == NULL)) { | |
376 | kfree_skb(skb); | |
377 | return -1; | |
378 | } | |
379 | if (idev->cnf.accept_source_route < 0) { | |
380 | in6_dev_put(idev); | |
381 | kfree_skb(skb); | |
382 | return -1; | |
383 | } | |
384 | ||
385 | if (accept_source_route > idev->cnf.accept_source_route) | |
386 | accept_source_route = idev->cnf.accept_source_route; | |
387 | ||
388 | in6_dev_put(idev); | |
389 | ||
390 | if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) || | |
391 | !pskb_may_pull(skb, (skb_transport_offset(skb) + | |
392 | ((skb_transport_header(skb)[1] + 1) << 3)))) { | |
393 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), | |
394 | IPSTATS_MIB_INHDRERRORS); | |
395 | kfree_skb(skb); | |
396 | return -1; | |
397 | } | |
398 | ||
399 | hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); | |
400 | ||
401 | switch (hdr->type) { | |
402 | #ifdef CONFIG_IPV6_MIP6 | |
403 | break; | |
404 | #endif | |
405 | case IPV6_SRCRT_TYPE_0: | |
406 | if (accept_source_route > 0) | |
407 | break; | |
408 | kfree_skb(skb); | |
409 | return -1; | |
410 | default: | |
411 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), | |
412 | IPSTATS_MIB_INHDRERRORS); | |
413 | icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, | |
414 | (&hdr->type) - skb_network_header(skb)); | |
415 | return -1; | |
416 | } | |
417 | ||
418 | if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) || | |
419 | skb->pkt_type != PACKET_HOST) { | |
420 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), | |
421 | IPSTATS_MIB_INADDRERRORS); | |
422 | kfree_skb(skb); | |
423 | return -1; | |
424 | } | |
425 | ||
426 | looped_back: | |
427 | if (hdr->segments_left == 0) { | |
428 | switch (hdr->type) { | |
429 | #ifdef CONFIG_IPV6_MIP6 | |
430 | case IPV6_SRCRT_TYPE_2: | |
431 | /* Silently discard type 2 header unless it was | |
432 | * processed by own | |
433 | */ | |
434 | if (!addr) { | |
435 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), | |
436 | IPSTATS_MIB_INADDRERRORS); | |
437 | kfree_skb(skb); | |
438 | return -1; | |
439 | } | |
440 | break; | |
441 | #endif | |
442 | default: | |
443 | break; | |
444 | } | |
445 | ||
446 | opt->lastopt = opt->srcrt = skb->h.raw - skb->nh.raw; | |
447 | skb->h.raw += (hdr->hdrlen + 1) << 3; | |
448 | opt->dst0 = opt->dst1; | |
449 | opt->dst1 = 0; | |
450 | opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); | |
451 | return 1; | |
452 | } | |
453 | ||
454 | switch (hdr->type) { | |
455 | case IPV6_SRCRT_TYPE_0: | |
456 | if (hdr->hdrlen & 0x01) { | |
457 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), | |
458 | IPSTATS_MIB_INHDRERRORS); | |
459 | icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, | |
460 | ((&hdr->hdrlen) - | |
461 | skb_network_header(skb))); | |
462 | return -1; | |
463 | } | |
464 | break; | |
465 | #ifdef CONFIG_IPV6_MIP6 | |
466 | case IPV6_SRCRT_TYPE_2: | |
467 | /* Silently discard invalid RTH type 2 */ | |
468 | if (hdr->hdrlen != 2 || hdr->segments_left != 1) { | |
469 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), | |
470 | IPSTATS_MIB_INHDRERRORS); | |
471 | kfree_skb(skb); | |
472 | return -1; | |
473 | } | |
474 | break; | |
475 | #endif | |
476 | } | |
477 | ||
478 | /* | |
479 | * This is the routing header forwarding algorithm from | |
480 | * RFC 2460, page 16. | |
481 | */ | |
482 | ||
483 | n = hdr->hdrlen >> 1; | |
484 | ||
485 | if (hdr->segments_left > n) { | |
486 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), | |
487 | IPSTATS_MIB_INHDRERRORS); | |
488 | icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, | |
489 | ((&hdr->segments_left) - | |
490 | skb_network_header(skb))); | |
491 | return -1; | |
492 | } | |
493 | ||
494 | /* We are about to mangle packet header. Be careful! | |
495 | Do not damage packets queued somewhere. | |
496 | */ | |
497 | if (skb_cloned(skb)) { | |
498 | struct sk_buff *skb2 = skb_copy(skb, GFP_ATOMIC); | |
499 | /* the copy is a forwarded packet */ | |
500 | if (skb2 == NULL) { | |
501 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), | |
502 | IPSTATS_MIB_OUTDISCARDS); | |
503 | kfree_skb(skb); | |
504 | return -1; | |
505 | } | |
506 | kfree_skb(skb); | |
507 | *skbp = skb = skb2; | |
508 | opt = IP6CB(skb2); | |
509 | hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb2); | |
510 | } | |
511 | ||
512 | if (skb->ip_summed == CHECKSUM_COMPLETE) | |
513 | skb->ip_summed = CHECKSUM_NONE; | |
514 | ||
515 | i = n - --hdr->segments_left; | |
516 | ||
517 | rthdr = (struct rt0_hdr *) hdr; | |
518 | addr = rthdr->addr; | |
519 | addr += i - 1; | |
520 | ||
521 | switch (hdr->type) { | |
522 | #ifdef CONFIG_IPV6_MIP6 | |
523 | case IPV6_SRCRT_TYPE_2: | |
524 | if (xfrm6_input_addr(skb, (xfrm_address_t *)addr, | |
525 | (xfrm_address_t *)&ipv6_hdr(skb)->saddr, | |
526 | IPPROTO_ROUTING) < 0) { | |
527 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), | |
528 | IPSTATS_MIB_INADDRERRORS); | |
529 | kfree_skb(skb); | |
530 | return -1; | |
531 | } | |
532 | if (!ipv6_chk_home_addr(addr)) { | |
533 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), | |
534 | IPSTATS_MIB_INADDRERRORS); | |
535 | kfree_skb(skb); | |
536 | return -1; | |
537 | } | |
538 | break; | |
539 | #endif | |
540 | default: | |
541 | break; | |
542 | } | |
543 | ||
544 | if (ipv6_addr_is_multicast(addr)) { | |
545 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), | |
546 | IPSTATS_MIB_INADDRERRORS); | |
547 | kfree_skb(skb); | |
548 | return -1; | |
549 | } | |
550 | ||
551 | ipv6_addr_copy(&daddr, addr); | |
552 | ipv6_addr_copy(addr, &ipv6_hdr(skb)->daddr); | |
553 | ipv6_addr_copy(&ipv6_hdr(skb)->daddr, &daddr); | |
554 | ||
555 | dst_release(xchg(&skb->dst, NULL)); | |
556 | ip6_route_input(skb); | |
557 | if (skb->dst->error) { | |
558 | skb_push(skb, skb->data - skb_network_header(skb)); | |
559 | dst_input(skb); | |
560 | return -1; | |
561 | } | |
562 | ||
563 | if (skb->dst->dev->flags&IFF_LOOPBACK) { | |
564 | if (ipv6_hdr(skb)->hop_limit <= 1) { | |
565 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), | |
566 | IPSTATS_MIB_INHDRERRORS); | |
567 | icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, | |
568 | 0, skb->dev); | |
569 | kfree_skb(skb); | |
570 | return -1; | |
571 | } | |
572 | ipv6_hdr(skb)->hop_limit--; | |
573 | goto looped_back; | |
574 | } | |
575 | ||
576 | skb_push(skb, skb->data - skb_network_header(skb)); | |
577 | dst_input(skb); | |
578 | return -1; | |
579 | } | |
580 | ||
581 | static struct inet6_protocol rthdr_protocol = { | |
582 | .handler = ipv6_rthdr_rcv, | |
583 | .flags = INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR, | |
584 | }; | |
585 | ||
586 | void __init ipv6_rthdr_init(void) | |
587 | { | |
588 | if (inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING) < 0) | |
589 | printk(KERN_ERR "ipv6_rthdr_init: Could not register protocol\n"); | |
590 | }; | |
591 | ||
592 | /* | |
593 | This function inverts received rthdr. | |
594 | NOTE: specs allow to make it automatically only if | |
595 | packet authenticated. | |
596 | ||
597 | I will not discuss it here (though, I am really pissed off at | |
598 | this stupid requirement making rthdr idea useless) | |
599 | ||
600 | Actually, it creates severe problems for us. | |
601 | Embryonic requests has no associated sockets, | |
602 | so that user have no control over it and | |
603 | cannot not only to set reply options, but | |
604 | even to know, that someone wants to connect | |
605 | without success. :-( | |
606 | ||
607 | For now we need to test the engine, so that I created | |
608 | temporary (or permanent) backdoor. | |
609 | If listening socket set IPV6_RTHDR to 2, then we invert header. | |
610 | --ANK (980729) | |
611 | */ | |
612 | ||
613 | struct ipv6_txoptions * | |
614 | ipv6_invert_rthdr(struct sock *sk, struct ipv6_rt_hdr *hdr) | |
615 | { | |
616 | /* Received rthdr: | |
617 | ||
618 | [ H1 -> H2 -> ... H_prev ] daddr=ME | |
619 | ||
620 | Inverted result: | |
621 | [ H_prev -> ... -> H1 ] daddr =sender | |
622 | ||
623 | Note, that IP output engine will rewrite this rthdr | |
624 | by rotating it left by one addr. | |
625 | */ | |
626 | ||
627 | int n, i; | |
628 | struct rt0_hdr *rthdr = (struct rt0_hdr*)hdr; | |
629 | struct rt0_hdr *irthdr; | |
630 | struct ipv6_txoptions *opt; | |
631 | int hdrlen = ipv6_optlen(hdr); | |
632 | ||
633 | if (hdr->segments_left || | |
634 | hdr->type != IPV6_SRCRT_TYPE_0 || | |
635 | hdr->hdrlen & 0x01) | |
636 | return NULL; | |
637 | ||
638 | n = hdr->hdrlen >> 1; | |
639 | opt = sock_kmalloc(sk, sizeof(*opt) + hdrlen, GFP_ATOMIC); | |
640 | if (opt == NULL) | |
641 | return NULL; | |
642 | memset(opt, 0, sizeof(*opt)); | |
643 | opt->tot_len = sizeof(*opt) + hdrlen; | |
644 | opt->srcrt = (void*)(opt+1); | |
645 | opt->opt_nflen = hdrlen; | |
646 | ||
647 | memcpy(opt->srcrt, hdr, sizeof(*hdr)); | |
648 | irthdr = (struct rt0_hdr*)opt->srcrt; | |
649 | irthdr->reserved = 0; | |
650 | opt->srcrt->segments_left = n; | |
651 | for (i=0; i<n; i++) | |
652 | memcpy(irthdr->addr+i, rthdr->addr+(n-1-i), 16); | |
653 | return opt; | |
654 | } | |
655 | ||
656 | EXPORT_SYMBOL_GPL(ipv6_invert_rthdr); | |
657 | ||
658 | /********************************** | |
659 | Hop-by-hop options. | |
660 | **********************************/ | |
661 | ||
662 | /* Router Alert as of RFC 2711 */ | |
663 | ||
664 | static int ipv6_hop_ra(struct sk_buff **skbp, int optoff) | |
665 | { | |
666 | struct sk_buff *skb = *skbp; | |
667 | const unsigned char *nh = skb_network_header(skb); | |
668 | ||
669 | if (nh[optoff + 1] == 2) { | |
670 | IP6CB(skb)->ra = optoff; | |
671 | return 1; | |
672 | } | |
673 | LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_ra: wrong RA length %d\n", | |
674 | nh[optoff + 1]); | |
675 | kfree_skb(skb); | |
676 | return 0; | |
677 | } | |
678 | ||
679 | /* Jumbo payload */ | |
680 | ||
681 | static int ipv6_hop_jumbo(struct sk_buff **skbp, int optoff) | |
682 | { | |
683 | struct sk_buff *skb = *skbp; | |
684 | const unsigned char *nh = skb_network_header(skb); | |
685 | u32 pkt_len; | |
686 | ||
687 | if (nh[optoff + 1] != 4 || (optoff & 3) != 2) { | |
688 | LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n", | |
689 | nh[optoff+1]); | |
690 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), | |
691 | IPSTATS_MIB_INHDRERRORS); | |
692 | goto drop; | |
693 | } | |
694 | ||
695 | pkt_len = ntohl(*(__be32 *)(nh + optoff + 2)); | |
696 | if (pkt_len <= IPV6_MAXPLEN) { | |
697 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS); | |
698 | icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2); | |
699 | return 0; | |
700 | } | |
701 | if (ipv6_hdr(skb)->payload_len) { | |
702 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS); | |
703 | icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff); | |
704 | return 0; | |
705 | } | |
706 | ||
707 | if (pkt_len > skb->len - sizeof(struct ipv6hdr)) { | |
708 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INTRUNCATEDPKTS); | |
709 | goto drop; | |
710 | } | |
711 | ||
712 | if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) | |
713 | goto drop; | |
714 | ||
715 | return 1; | |
716 | ||
717 | drop: | |
718 | kfree_skb(skb); | |
719 | return 0; | |
720 | } | |
721 | ||
722 | static struct tlvtype_proc tlvprochopopt_lst[] = { | |
723 | { | |
724 | .type = IPV6_TLV_ROUTERALERT, | |
725 | .func = ipv6_hop_ra, | |
726 | }, | |
727 | { | |
728 | .type = IPV6_TLV_JUMBO, | |
729 | .func = ipv6_hop_jumbo, | |
730 | }, | |
731 | { -1, } | |
732 | }; | |
733 | ||
734 | int ipv6_parse_hopopts(struct sk_buff **skbp) | |
735 | { | |
736 | struct sk_buff *skb = *skbp; | |
737 | struct inet6_skb_parm *opt = IP6CB(skb); | |
738 | ||
739 | /* | |
740 | * skb_network_header(skb) is equal to skb->data, and | |
741 | * skb->h.raw - skb->nh.raw is always equal to | |
742 | * sizeof(struct ipv6hdr) by definition of | |
743 | * hop-by-hop options. | |
744 | */ | |
745 | if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) || | |
746 | !pskb_may_pull(skb, (sizeof(struct ipv6hdr) + | |
747 | ((skb_transport_header(skb)[1] + 1) << 3)))) { | |
748 | kfree_skb(skb); | |
749 | return -1; | |
750 | } | |
751 | ||
752 | opt->hop = sizeof(struct ipv6hdr); | |
753 | if (ip6_parse_tlv(tlvprochopopt_lst, skbp)) { | |
754 | skb = *skbp; | |
755 | skb->h.raw += (skb_transport_header(skb)[1] + 1) << 3; | |
756 | opt = IP6CB(skb); | |
757 | opt->nhoff = sizeof(struct ipv6hdr); | |
758 | return 1; | |
759 | } | |
760 | return -1; | |
761 | } | |
762 | ||
763 | /* | |
764 | * Creating outbound headers. | |
765 | * | |
766 | * "build" functions work when skb is filled from head to tail (datagram) | |
767 | * "push" functions work when headers are added from tail to head (tcp) | |
768 | * | |
769 | * In both cases we assume, that caller reserved enough room | |
770 | * for headers. | |
771 | */ | |
772 | ||
773 | static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto, | |
774 | struct ipv6_rt_hdr *opt, | |
775 | struct in6_addr **addr_p) | |
776 | { | |
777 | struct rt0_hdr *phdr, *ihdr; | |
778 | int hops; | |
779 | ||
780 | ihdr = (struct rt0_hdr *) opt; | |
781 | ||
782 | phdr = (struct rt0_hdr *) skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3); | |
783 | memcpy(phdr, ihdr, sizeof(struct rt0_hdr)); | |
784 | ||
785 | hops = ihdr->rt_hdr.hdrlen >> 1; | |
786 | ||
787 | if (hops > 1) | |
788 | memcpy(phdr->addr, ihdr->addr + 1, | |
789 | (hops - 1) * sizeof(struct in6_addr)); | |
790 | ||
791 | ipv6_addr_copy(phdr->addr + (hops - 1), *addr_p); | |
792 | *addr_p = ihdr->addr; | |
793 | ||
794 | phdr->rt_hdr.nexthdr = *proto; | |
795 | *proto = NEXTHDR_ROUTING; | |
796 | } | |
797 | ||
798 | static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt) | |
799 | { | |
800 | struct ipv6_opt_hdr *h = (struct ipv6_opt_hdr *)skb_push(skb, ipv6_optlen(opt)); | |
801 | ||
802 | memcpy(h, opt, ipv6_optlen(opt)); | |
803 | h->nexthdr = *proto; | |
804 | *proto = type; | |
805 | } | |
806 | ||
807 | void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, | |
808 | u8 *proto, | |
809 | struct in6_addr **daddr) | |
810 | { | |
811 | if (opt->srcrt) { | |
812 | ipv6_push_rthdr(skb, proto, opt->srcrt, daddr); | |
813 | /* | |
814 | * IPV6_RTHDRDSTOPTS is ignored | |
815 | * unless IPV6_RTHDR is set (RFC3542). | |
816 | */ | |
817 | if (opt->dst0opt) | |
818 | ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt); | |
819 | } | |
820 | if (opt->hopopt) | |
821 | ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt); | |
822 | } | |
823 | ||
824 | EXPORT_SYMBOL(ipv6_push_nfrag_opts); | |
825 | ||
826 | void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto) | |
827 | { | |
828 | if (opt->dst1opt) | |
829 | ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt); | |
830 | } | |
831 | ||
832 | struct ipv6_txoptions * | |
833 | ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt) | |
834 | { | |
835 | struct ipv6_txoptions *opt2; | |
836 | ||
837 | opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC); | |
838 | if (opt2) { | |
839 | long dif = (char*)opt2 - (char*)opt; | |
840 | memcpy(opt2, opt, opt->tot_len); | |
841 | if (opt2->hopopt) | |
842 | *((char**)&opt2->hopopt) += dif; | |
843 | if (opt2->dst0opt) | |
844 | *((char**)&opt2->dst0opt) += dif; | |
845 | if (opt2->dst1opt) | |
846 | *((char**)&opt2->dst1opt) += dif; | |
847 | if (opt2->srcrt) | |
848 | *((char**)&opt2->srcrt) += dif; | |
849 | } | |
850 | return opt2; | |
851 | } | |
852 | ||
853 | EXPORT_SYMBOL_GPL(ipv6_dup_options); | |
854 | ||
855 | static int ipv6_renew_option(void *ohdr, | |
856 | struct ipv6_opt_hdr __user *newopt, int newoptlen, | |
857 | int inherit, | |
858 | struct ipv6_opt_hdr **hdr, | |
859 | char **p) | |
860 | { | |
861 | if (inherit) { | |
862 | if (ohdr) { | |
863 | memcpy(*p, ohdr, ipv6_optlen((struct ipv6_opt_hdr *)ohdr)); | |
864 | *hdr = (struct ipv6_opt_hdr *)*p; | |
865 | *p += CMSG_ALIGN(ipv6_optlen(*(struct ipv6_opt_hdr **)hdr)); | |
866 | } | |
867 | } else { | |
868 | if (newopt) { | |
869 | if (copy_from_user(*p, newopt, newoptlen)) | |
870 | return -EFAULT; | |
871 | *hdr = (struct ipv6_opt_hdr *)*p; | |
872 | if (ipv6_optlen(*(struct ipv6_opt_hdr **)hdr) > newoptlen) | |
873 | return -EINVAL; | |
874 | *p += CMSG_ALIGN(newoptlen); | |
875 | } | |
876 | } | |
877 | return 0; | |
878 | } | |
879 | ||
880 | struct ipv6_txoptions * | |
881 | ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt, | |
882 | int newtype, | |
883 | struct ipv6_opt_hdr __user *newopt, int newoptlen) | |
884 | { | |
885 | int tot_len = 0; | |
886 | char *p; | |
887 | struct ipv6_txoptions *opt2; | |
888 | int err; | |
889 | ||
890 | if (opt) { | |
891 | if (newtype != IPV6_HOPOPTS && opt->hopopt) | |
892 | tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt)); | |
893 | if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt) | |
894 | tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt)); | |
895 | if (newtype != IPV6_RTHDR && opt->srcrt) | |
896 | tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt)); | |
897 | if (newtype != IPV6_DSTOPTS && opt->dst1opt) | |
898 | tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt)); | |
899 | } | |
900 | ||
901 | if (newopt && newoptlen) | |
902 | tot_len += CMSG_ALIGN(newoptlen); | |
903 | ||
904 | if (!tot_len) | |
905 | return NULL; | |
906 | ||
907 | tot_len += sizeof(*opt2); | |
908 | opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC); | |
909 | if (!opt2) | |
910 | return ERR_PTR(-ENOBUFS); | |
911 | ||
912 | memset(opt2, 0, tot_len); | |
913 | ||
914 | opt2->tot_len = tot_len; | |
915 | p = (char *)(opt2 + 1); | |
916 | ||
917 | err = ipv6_renew_option(opt ? opt->hopopt : NULL, newopt, newoptlen, | |
918 | newtype != IPV6_HOPOPTS, | |
919 | &opt2->hopopt, &p); | |
920 | if (err) | |
921 | goto out; | |
922 | ||
923 | err = ipv6_renew_option(opt ? opt->dst0opt : NULL, newopt, newoptlen, | |
924 | newtype != IPV6_RTHDRDSTOPTS, | |
925 | &opt2->dst0opt, &p); | |
926 | if (err) | |
927 | goto out; | |
928 | ||
929 | err = ipv6_renew_option(opt ? opt->srcrt : NULL, newopt, newoptlen, | |
930 | newtype != IPV6_RTHDR, | |
931 | (struct ipv6_opt_hdr **)&opt2->srcrt, &p); | |
932 | if (err) | |
933 | goto out; | |
934 | ||
935 | err = ipv6_renew_option(opt ? opt->dst1opt : NULL, newopt, newoptlen, | |
936 | newtype != IPV6_DSTOPTS, | |
937 | &opt2->dst1opt, &p); | |
938 | if (err) | |
939 | goto out; | |
940 | ||
941 | opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) + | |
942 | (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) + | |
943 | (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0); | |
944 | opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0); | |
945 | ||
946 | return opt2; | |
947 | out: | |
948 | sock_kfree_s(sk, opt2, opt2->tot_len); | |
949 | return ERR_PTR(err); | |
950 | } | |
951 | ||
952 | struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space, | |
953 | struct ipv6_txoptions *opt) | |
954 | { | |
955 | /* | |
956 | * ignore the dest before srcrt unless srcrt is being included. | |
957 | * --yoshfuji | |
958 | */ | |
959 | if (opt && opt->dst0opt && !opt->srcrt) { | |
960 | if (opt_space != opt) { | |
961 | memcpy(opt_space, opt, sizeof(*opt_space)); | |
962 | opt = opt_space; | |
963 | } | |
964 | opt->opt_nflen -= ipv6_optlen(opt->dst0opt); | |
965 | opt->dst0opt = NULL; | |
966 | } | |
967 | ||
968 | return opt; | |
969 | } | |
970 |