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[IPV4]: Add 'rtable' field in struct sk_buff to alias 'dst' and avoid casts
[deliverable/linux.git] / net / ipv4 / ip_options.c
1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * The options processing module for ip.c
7 *
8 * Version: $Id: ip_options.c,v 1.21 2001/09/01 00:31:50 davem Exp $
9 *
10 * Authors: A.N.Kuznetsov
11 *
12 */
13
14 #include <linux/capability.h>
15 #include <linux/module.h>
16 #include <linux/types.h>
17 #include <asm/uaccess.h>
18 #include <linux/skbuff.h>
19 #include <linux/ip.h>
20 #include <linux/icmp.h>
21 #include <linux/netdevice.h>
22 #include <linux/rtnetlink.h>
23 #include <net/sock.h>
24 #include <net/ip.h>
25 #include <net/icmp.h>
26 #include <net/route.h>
27 #include <net/cipso_ipv4.h>
28
29 /*
30 * Write options to IP header, record destination address to
31 * source route option, address of outgoing interface
32 * (we should already know it, so that this function is allowed be
33 * called only after routing decision) and timestamp,
34 * if we originate this datagram.
35 *
36 * daddr is real destination address, next hop is recorded in IP header.
37 * saddr is address of outgoing interface.
38 */
39
40 void ip_options_build(struct sk_buff * skb, struct ip_options * opt,
41 __be32 daddr, struct rtable *rt, int is_frag)
42 {
43 unsigned char *iph = skb_network_header(skb);
44
45 memcpy(&(IPCB(skb)->opt), opt, sizeof(struct ip_options));
46 memcpy(iph+sizeof(struct iphdr), opt->__data, opt->optlen);
47 opt = &(IPCB(skb)->opt);
48 opt->is_data = 0;
49
50 if (opt->srr)
51 memcpy(iph+opt->srr+iph[opt->srr+1]-4, &daddr, 4);
52
53 if (!is_frag) {
54 if (opt->rr_needaddr)
55 ip_rt_get_source(iph+opt->rr+iph[opt->rr+2]-5, rt);
56 if (opt->ts_needaddr)
57 ip_rt_get_source(iph+opt->ts+iph[opt->ts+2]-9, rt);
58 if (opt->ts_needtime) {
59 struct timeval tv;
60 __be32 midtime;
61 do_gettimeofday(&tv);
62 midtime = htonl((tv.tv_sec % 86400) * 1000 + tv.tv_usec / 1000);
63 memcpy(iph+opt->ts+iph[opt->ts+2]-5, &midtime, 4);
64 }
65 return;
66 }
67 if (opt->rr) {
68 memset(iph+opt->rr, IPOPT_NOP, iph[opt->rr+1]);
69 opt->rr = 0;
70 opt->rr_needaddr = 0;
71 }
72 if (opt->ts) {
73 memset(iph+opt->ts, IPOPT_NOP, iph[opt->ts+1]);
74 opt->ts = 0;
75 opt->ts_needaddr = opt->ts_needtime = 0;
76 }
77 }
78
79 /*
80 * Provided (sopt, skb) points to received options,
81 * build in dopt compiled option set appropriate for answering.
82 * i.e. invert SRR option, copy anothers,
83 * and grab room in RR/TS options.
84 *
85 * NOTE: dopt cannot point to skb.
86 */
87
88 int ip_options_echo(struct ip_options * dopt, struct sk_buff * skb)
89 {
90 struct ip_options *sopt;
91 unsigned char *sptr, *dptr;
92 int soffset, doffset;
93 int optlen;
94 __be32 daddr;
95
96 memset(dopt, 0, sizeof(struct ip_options));
97
98 dopt->is_data = 1;
99
100 sopt = &(IPCB(skb)->opt);
101
102 if (sopt->optlen == 0) {
103 dopt->optlen = 0;
104 return 0;
105 }
106
107 sptr = skb_network_header(skb);
108 dptr = dopt->__data;
109
110 daddr = skb->rtable->rt_spec_dst;
111
112 if (sopt->rr) {
113 optlen = sptr[sopt->rr+1];
114 soffset = sptr[sopt->rr+2];
115 dopt->rr = dopt->optlen + sizeof(struct iphdr);
116 memcpy(dptr, sptr+sopt->rr, optlen);
117 if (sopt->rr_needaddr && soffset <= optlen) {
118 if (soffset + 3 > optlen)
119 return -EINVAL;
120 dptr[2] = soffset + 4;
121 dopt->rr_needaddr = 1;
122 }
123 dptr += optlen;
124 dopt->optlen += optlen;
125 }
126 if (sopt->ts) {
127 optlen = sptr[sopt->ts+1];
128 soffset = sptr[sopt->ts+2];
129 dopt->ts = dopt->optlen + sizeof(struct iphdr);
130 memcpy(dptr, sptr+sopt->ts, optlen);
131 if (soffset <= optlen) {
132 if (sopt->ts_needaddr) {
133 if (soffset + 3 > optlen)
134 return -EINVAL;
135 dopt->ts_needaddr = 1;
136 soffset += 4;
137 }
138 if (sopt->ts_needtime) {
139 if (soffset + 3 > optlen)
140 return -EINVAL;
141 if ((dptr[3]&0xF) != IPOPT_TS_PRESPEC) {
142 dopt->ts_needtime = 1;
143 soffset += 4;
144 } else {
145 dopt->ts_needtime = 0;
146
147 if (soffset + 8 <= optlen) {
148 __be32 addr;
149
150 memcpy(&addr, sptr+soffset-1, 4);
151 if (inet_addr_type(&init_net, addr) != RTN_LOCAL) {
152 dopt->ts_needtime = 1;
153 soffset += 8;
154 }
155 }
156 }
157 }
158 dptr[2] = soffset;
159 }
160 dptr += optlen;
161 dopt->optlen += optlen;
162 }
163 if (sopt->srr) {
164 unsigned char * start = sptr+sopt->srr;
165 __be32 faddr;
166
167 optlen = start[1];
168 soffset = start[2];
169 doffset = 0;
170 if (soffset > optlen)
171 soffset = optlen + 1;
172 soffset -= 4;
173 if (soffset > 3) {
174 memcpy(&faddr, &start[soffset-1], 4);
175 for (soffset-=4, doffset=4; soffset > 3; soffset-=4, doffset+=4)
176 memcpy(&dptr[doffset-1], &start[soffset-1], 4);
177 /*
178 * RFC1812 requires to fix illegal source routes.
179 */
180 if (memcmp(&ip_hdr(skb)->saddr,
181 &start[soffset + 3], 4) == 0)
182 doffset -= 4;
183 }
184 if (doffset > 3) {
185 memcpy(&start[doffset-1], &daddr, 4);
186 dopt->faddr = faddr;
187 dptr[0] = start[0];
188 dptr[1] = doffset+3;
189 dptr[2] = 4;
190 dptr += doffset+3;
191 dopt->srr = dopt->optlen + sizeof(struct iphdr);
192 dopt->optlen += doffset+3;
193 dopt->is_strictroute = sopt->is_strictroute;
194 }
195 }
196 if (sopt->cipso) {
197 optlen = sptr[sopt->cipso+1];
198 dopt->cipso = dopt->optlen+sizeof(struct iphdr);
199 memcpy(dptr, sptr+sopt->cipso, optlen);
200 dptr += optlen;
201 dopt->optlen += optlen;
202 }
203 while (dopt->optlen & 3) {
204 *dptr++ = IPOPT_END;
205 dopt->optlen++;
206 }
207 return 0;
208 }
209
210 /*
211 * Options "fragmenting", just fill options not
212 * allowed in fragments with NOOPs.
213 * Simple and stupid 8), but the most efficient way.
214 */
215
216 void ip_options_fragment(struct sk_buff * skb)
217 {
218 unsigned char *optptr = skb_network_header(skb) + sizeof(struct iphdr);
219 struct ip_options * opt = &(IPCB(skb)->opt);
220 int l = opt->optlen;
221 int optlen;
222
223 while (l > 0) {
224 switch (*optptr) {
225 case IPOPT_END:
226 return;
227 case IPOPT_NOOP:
228 l--;
229 optptr++;
230 continue;
231 }
232 optlen = optptr[1];
233 if (optlen<2 || optlen>l)
234 return;
235 if (!IPOPT_COPIED(*optptr))
236 memset(optptr, IPOPT_NOOP, optlen);
237 l -= optlen;
238 optptr += optlen;
239 }
240 opt->ts = 0;
241 opt->rr = 0;
242 opt->rr_needaddr = 0;
243 opt->ts_needaddr = 0;
244 opt->ts_needtime = 0;
245 return;
246 }
247
248 /*
249 * Verify options and fill pointers in struct options.
250 * Caller should clear *opt, and set opt->data.
251 * If opt == NULL, then skb->data should point to IP header.
252 */
253
254 int ip_options_compile(struct ip_options * opt, struct sk_buff * skb)
255 {
256 int l;
257 unsigned char * iph;
258 unsigned char * optptr;
259 int optlen;
260 unsigned char * pp_ptr = NULL;
261 struct rtable *rt = skb ? skb->rtable : NULL;
262
263 if (!opt) {
264 opt = &(IPCB(skb)->opt);
265 iph = skb_network_header(skb);
266 opt->optlen = ((struct iphdr *)iph)->ihl*4 - sizeof(struct iphdr);
267 optptr = iph + sizeof(struct iphdr);
268 opt->is_data = 0;
269 } else {
270 optptr = opt->is_data ? opt->__data :
271 (unsigned char *)&(ip_hdr(skb)[1]);
272 iph = optptr - sizeof(struct iphdr);
273 }
274
275 for (l = opt->optlen; l > 0; ) {
276 switch (*optptr) {
277 case IPOPT_END:
278 for (optptr++, l--; l>0; optptr++, l--) {
279 if (*optptr != IPOPT_END) {
280 *optptr = IPOPT_END;
281 opt->is_changed = 1;
282 }
283 }
284 goto eol;
285 case IPOPT_NOOP:
286 l--;
287 optptr++;
288 continue;
289 }
290 optlen = optptr[1];
291 if (optlen<2 || optlen>l) {
292 pp_ptr = optptr;
293 goto error;
294 }
295 switch (*optptr) {
296 case IPOPT_SSRR:
297 case IPOPT_LSRR:
298 if (optlen < 3) {
299 pp_ptr = optptr + 1;
300 goto error;
301 }
302 if (optptr[2] < 4) {
303 pp_ptr = optptr + 2;
304 goto error;
305 }
306 /* NB: cf RFC-1812 5.2.4.1 */
307 if (opt->srr) {
308 pp_ptr = optptr;
309 goto error;
310 }
311 if (!skb) {
312 if (optptr[2] != 4 || optlen < 7 || ((optlen-3) & 3)) {
313 pp_ptr = optptr + 1;
314 goto error;
315 }
316 memcpy(&opt->faddr, &optptr[3], 4);
317 if (optlen > 7)
318 memmove(&optptr[3], &optptr[7], optlen-7);
319 }
320 opt->is_strictroute = (optptr[0] == IPOPT_SSRR);
321 opt->srr = optptr - iph;
322 break;
323 case IPOPT_RR:
324 if (opt->rr) {
325 pp_ptr = optptr;
326 goto error;
327 }
328 if (optlen < 3) {
329 pp_ptr = optptr + 1;
330 goto error;
331 }
332 if (optptr[2] < 4) {
333 pp_ptr = optptr + 2;
334 goto error;
335 }
336 if (optptr[2] <= optlen) {
337 if (optptr[2]+3 > optlen) {
338 pp_ptr = optptr + 2;
339 goto error;
340 }
341 if (skb) {
342 memcpy(&optptr[optptr[2]-1], &rt->rt_spec_dst, 4);
343 opt->is_changed = 1;
344 }
345 optptr[2] += 4;
346 opt->rr_needaddr = 1;
347 }
348 opt->rr = optptr - iph;
349 break;
350 case IPOPT_TIMESTAMP:
351 if (opt->ts) {
352 pp_ptr = optptr;
353 goto error;
354 }
355 if (optlen < 4) {
356 pp_ptr = optptr + 1;
357 goto error;
358 }
359 if (optptr[2] < 5) {
360 pp_ptr = optptr + 2;
361 goto error;
362 }
363 if (optptr[2] <= optlen) {
364 __be32 *timeptr = NULL;
365 if (optptr[2]+3 > optptr[1]) {
366 pp_ptr = optptr + 2;
367 goto error;
368 }
369 switch (optptr[3]&0xF) {
370 case IPOPT_TS_TSONLY:
371 opt->ts = optptr - iph;
372 if (skb)
373 timeptr = (__be32*)&optptr[optptr[2]-1];
374 opt->ts_needtime = 1;
375 optptr[2] += 4;
376 break;
377 case IPOPT_TS_TSANDADDR:
378 if (optptr[2]+7 > optptr[1]) {
379 pp_ptr = optptr + 2;
380 goto error;
381 }
382 opt->ts = optptr - iph;
383 if (skb) {
384 memcpy(&optptr[optptr[2]-1], &rt->rt_spec_dst, 4);
385 timeptr = (__be32*)&optptr[optptr[2]+3];
386 }
387 opt->ts_needaddr = 1;
388 opt->ts_needtime = 1;
389 optptr[2] += 8;
390 break;
391 case IPOPT_TS_PRESPEC:
392 if (optptr[2]+7 > optptr[1]) {
393 pp_ptr = optptr + 2;
394 goto error;
395 }
396 opt->ts = optptr - iph;
397 {
398 __be32 addr;
399 memcpy(&addr, &optptr[optptr[2]-1], 4);
400 if (inet_addr_type(&init_net, addr) == RTN_UNICAST)
401 break;
402 if (skb)
403 timeptr = (__be32*)&optptr[optptr[2]+3];
404 }
405 opt->ts_needtime = 1;
406 optptr[2] += 8;
407 break;
408 default:
409 if (!skb && !capable(CAP_NET_RAW)) {
410 pp_ptr = optptr + 3;
411 goto error;
412 }
413 break;
414 }
415 if (timeptr) {
416 struct timeval tv;
417 __be32 midtime;
418 do_gettimeofday(&tv);
419 midtime = htonl((tv.tv_sec % 86400) * 1000 + tv.tv_usec / 1000);
420 memcpy(timeptr, &midtime, sizeof(__be32));
421 opt->is_changed = 1;
422 }
423 } else {
424 unsigned overflow = optptr[3]>>4;
425 if (overflow == 15) {
426 pp_ptr = optptr + 3;
427 goto error;
428 }
429 opt->ts = optptr - iph;
430 if (skb) {
431 optptr[3] = (optptr[3]&0xF)|((overflow+1)<<4);
432 opt->is_changed = 1;
433 }
434 }
435 break;
436 case IPOPT_RA:
437 if (optlen < 4) {
438 pp_ptr = optptr + 1;
439 goto error;
440 }
441 if (optptr[2] == 0 && optptr[3] == 0)
442 opt->router_alert = optptr - iph;
443 break;
444 case IPOPT_CIPSO:
445 if ((!skb && !capable(CAP_NET_RAW)) || opt->cipso) {
446 pp_ptr = optptr;
447 goto error;
448 }
449 opt->cipso = optptr - iph;
450 if (cipso_v4_validate(&optptr)) {
451 pp_ptr = optptr;
452 goto error;
453 }
454 break;
455 case IPOPT_SEC:
456 case IPOPT_SID:
457 default:
458 if (!skb && !capable(CAP_NET_RAW)) {
459 pp_ptr = optptr;
460 goto error;
461 }
462 break;
463 }
464 l -= optlen;
465 optptr += optlen;
466 }
467
468 eol:
469 if (!pp_ptr)
470 return 0;
471
472 error:
473 if (skb) {
474 icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl((pp_ptr-iph)<<24));
475 }
476 return -EINVAL;
477 }
478
479
480 /*
481 * Undo all the changes done by ip_options_compile().
482 */
483
484 void ip_options_undo(struct ip_options * opt)
485 {
486 if (opt->srr) {
487 unsigned char * optptr = opt->__data+opt->srr-sizeof(struct iphdr);
488 memmove(optptr+7, optptr+3, optptr[1]-7);
489 memcpy(optptr+3, &opt->faddr, 4);
490 }
491 if (opt->rr_needaddr) {
492 unsigned char * optptr = opt->__data+opt->rr-sizeof(struct iphdr);
493 optptr[2] -= 4;
494 memset(&optptr[optptr[2]-1], 0, 4);
495 }
496 if (opt->ts) {
497 unsigned char * optptr = opt->__data+opt->ts-sizeof(struct iphdr);
498 if (opt->ts_needtime) {
499 optptr[2] -= 4;
500 memset(&optptr[optptr[2]-1], 0, 4);
501 if ((optptr[3]&0xF) == IPOPT_TS_PRESPEC)
502 optptr[2] -= 4;
503 }
504 if (opt->ts_needaddr) {
505 optptr[2] -= 4;
506 memset(&optptr[optptr[2]-1], 0, 4);
507 }
508 }
509 }
510
511 static struct ip_options *ip_options_get_alloc(const int optlen)
512 {
513 return kzalloc(sizeof(struct ip_options) + ((optlen + 3) & ~3),
514 GFP_KERNEL);
515 }
516
517 static int ip_options_get_finish(struct ip_options **optp,
518 struct ip_options *opt, int optlen)
519 {
520 while (optlen & 3)
521 opt->__data[optlen++] = IPOPT_END;
522 opt->optlen = optlen;
523 opt->is_data = 1;
524 if (optlen && ip_options_compile(opt, NULL)) {
525 kfree(opt);
526 return -EINVAL;
527 }
528 kfree(*optp);
529 *optp = opt;
530 return 0;
531 }
532
533 int ip_options_get_from_user(struct ip_options **optp, unsigned char __user *data, int optlen)
534 {
535 struct ip_options *opt = ip_options_get_alloc(optlen);
536
537 if (!opt)
538 return -ENOMEM;
539 if (optlen && copy_from_user(opt->__data, data, optlen)) {
540 kfree(opt);
541 return -EFAULT;
542 }
543 return ip_options_get_finish(optp, opt, optlen);
544 }
545
546 int ip_options_get(struct ip_options **optp, unsigned char *data, int optlen)
547 {
548 struct ip_options *opt = ip_options_get_alloc(optlen);
549
550 if (!opt)
551 return -ENOMEM;
552 if (optlen)
553 memcpy(opt->__data, data, optlen);
554 return ip_options_get_finish(optp, opt, optlen);
555 }
556
557 void ip_forward_options(struct sk_buff *skb)
558 {
559 struct ip_options * opt = &(IPCB(skb)->opt);
560 unsigned char * optptr;
561 struct rtable *rt = skb->rtable;
562 unsigned char *raw = skb_network_header(skb);
563
564 if (opt->rr_needaddr) {
565 optptr = (unsigned char *)raw + opt->rr;
566 ip_rt_get_source(&optptr[optptr[2]-5], rt);
567 opt->is_changed = 1;
568 }
569 if (opt->srr_is_hit) {
570 int srrptr, srrspace;
571
572 optptr = raw + opt->srr;
573
574 for ( srrptr=optptr[2], srrspace = optptr[1];
575 srrptr <= srrspace;
576 srrptr += 4
577 ) {
578 if (srrptr + 3 > srrspace)
579 break;
580 if (memcmp(&rt->rt_dst, &optptr[srrptr-1], 4) == 0)
581 break;
582 }
583 if (srrptr + 3 <= srrspace) {
584 opt->is_changed = 1;
585 ip_rt_get_source(&optptr[srrptr-1], rt);
586 ip_hdr(skb)->daddr = rt->rt_dst;
587 optptr[2] = srrptr+4;
588 } else if (net_ratelimit())
589 printk(KERN_CRIT "ip_forward(): Argh! Destination lost!\n");
590 if (opt->ts_needaddr) {
591 optptr = raw + opt->ts;
592 ip_rt_get_source(&optptr[optptr[2]-9], rt);
593 opt->is_changed = 1;
594 }
595 }
596 if (opt->is_changed) {
597 opt->is_changed = 0;
598 ip_send_check(ip_hdr(skb));
599 }
600 }
601
602 int ip_options_rcv_srr(struct sk_buff *skb)
603 {
604 struct ip_options *opt = &(IPCB(skb)->opt);
605 int srrspace, srrptr;
606 __be32 nexthop;
607 struct iphdr *iph = ip_hdr(skb);
608 unsigned char *optptr = skb_network_header(skb) + opt->srr;
609 struct rtable *rt = skb->rtable;
610 struct rtable *rt2;
611 int err;
612
613 if (!opt->srr)
614 return 0;
615
616 if (skb->pkt_type != PACKET_HOST)
617 return -EINVAL;
618 if (rt->rt_type == RTN_UNICAST) {
619 if (!opt->is_strictroute)
620 return 0;
621 icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl(16<<24));
622 return -EINVAL;
623 }
624 if (rt->rt_type != RTN_LOCAL)
625 return -EINVAL;
626
627 for (srrptr=optptr[2], srrspace = optptr[1]; srrptr <= srrspace; srrptr += 4) {
628 if (srrptr + 3 > srrspace) {
629 icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl((opt->srr+2)<<24));
630 return -EINVAL;
631 }
632 memcpy(&nexthop, &optptr[srrptr-1], 4);
633
634 rt = skb->rtable;
635 skb->rtable = NULL;
636 err = ip_route_input(skb, nexthop, iph->saddr, iph->tos, skb->dev);
637 rt2 = skb->rtable;
638 if (err || (rt2->rt_type != RTN_UNICAST && rt2->rt_type != RTN_LOCAL)) {
639 ip_rt_put(rt2);
640 skb->rtable = rt;
641 return -EINVAL;
642 }
643 ip_rt_put(rt);
644 if (rt2->rt_type != RTN_LOCAL)
645 break;
646 /* Superfast 8) loopback forward */
647 memcpy(&iph->daddr, &optptr[srrptr-1], 4);
648 opt->is_changed = 1;
649 }
650 if (srrptr <= srrspace) {
651 opt->srr_is_hit = 1;
652 opt->is_changed = 1;
653 }
654 return 0;
655 }
Linux kernel - Deliverables
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