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[PATCH] delete from_swap_cache BUG_ONs
[linux-ginger.git] / net / ipv4 / ip_options.c
blobbce4e875193be1d596c4c607ab42e9e1f966513f
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/module.h>
15 #include <linux/types.h>
16 #include <asm/uaccess.h>
17 #include <linux/skbuff.h>
18 #include <linux/ip.h>
19 #include <linux/icmp.h>
20 #include <linux/netdevice.h>
21 #include <linux/rtnetlink.h>
22 #include <net/sock.h>
23 #include <net/ip.h>
24 #include <net/icmp.h>
25
26 /*
27 * Write options to IP header, record destination address to
28 * source route option, address of outgoing interface
29 * (we should already know it, so that this function is allowed be
30 * called only after routing decision) and timestamp,
31 * if we originate this datagram.
32 *
33 * daddr is real destination address, next hop is recorded in IP header.
34 * saddr is address of outgoing interface.
35 */
36
37 void ip_options_build(struct sk_buff * skb, struct ip_options * opt,
38 u32 daddr, struct rtable *rt, int is_frag)
39 {
40 unsigned char * iph = skb->nh.raw;
41
42 memcpy(&(IPCB(skb)->opt), opt, sizeof(struct ip_options));
43 memcpy(iph+sizeof(struct iphdr), opt->__data, opt->optlen);
44 opt = &(IPCB(skb)->opt);
45 opt->is_data = 0;
46
47 if (opt->srr)
48 memcpy(iph+opt->srr+iph[opt->srr+1]-4, &daddr, 4);
49
50 if (!is_frag) {
51 if (opt->rr_needaddr)
52 ip_rt_get_source(iph+opt->rr+iph[opt->rr+2]-5, rt);
53 if (opt->ts_needaddr)
54 ip_rt_get_source(iph+opt->ts+iph[opt->ts+2]-9, rt);
55 if (opt->ts_needtime) {
56 struct timeval tv;
57 __u32 midtime;
58 do_gettimeofday(&tv);
59 midtime = htonl((tv.tv_sec % 86400) * 1000 + tv.tv_usec / 1000);
60 memcpy(iph+opt->ts+iph[opt->ts+2]-5, &midtime, 4);
61 }
62 return;
63 }
64 if (opt->rr) {
65 memset(iph+opt->rr, IPOPT_NOP, iph[opt->rr+1]);
66 opt->rr = 0;
67 opt->rr_needaddr = 0;
68 }
69 if (opt->ts) {
70 memset(iph+opt->ts, IPOPT_NOP, iph[opt->ts+1]);
71 opt->ts = 0;
72 opt->ts_needaddr = opt->ts_needtime = 0;
73 }
74 }
75
76 /*
77 * Provided (sopt, skb) points to received options,
78 * build in dopt compiled option set appropriate for answering.
79 * i.e. invert SRR option, copy anothers,
80 * and grab room in RR/TS options.
81 *
82 * NOTE: dopt cannot point to skb.
83 */
84
85 int ip_options_echo(struct ip_options * dopt, struct sk_buff * skb)
86 {
87 struct ip_options *sopt;
88 unsigned char *sptr, *dptr;
89 int soffset, doffset;
90 int optlen;
91 u32 daddr;
92
93 memset(dopt, 0, sizeof(struct ip_options));
94
95 dopt->is_data = 1;
96
97 sopt = &(IPCB(skb)->opt);
98
99 if (sopt->optlen == 0) {
100 dopt->optlen = 0;
101 return 0;
102 }
103
104 sptr = skb->nh.raw;
105 dptr = dopt->__data;
106
107 if (skb->dst)
108 daddr = ((struct rtable*)skb->dst)->rt_spec_dst;
109 else
110 daddr = skb->nh.iph->daddr;
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 __u32 addr;
149
150 memcpy(&addr, sptr+soffset-1, 4);
151 if (inet_addr_type(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 u32 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(&skb->nh.iph->saddr, &start[soffset+3], 4) == 0)
181 doffset -= 4;
182 }
183 if (doffset > 3) {
184 memcpy(&start[doffset-1], &daddr, 4);
185 dopt->faddr = faddr;
186 dptr[0] = start[0];
187 dptr[1] = doffset+3;
188 dptr[2] = 4;
189 dptr += doffset+3;
190 dopt->srr = dopt->optlen + sizeof(struct iphdr);
191 dopt->optlen += doffset+3;
192 dopt->is_strictroute = sopt->is_strictroute;
193 }
194 }
195 while (dopt->optlen & 3) {
196 *dptr++ = IPOPT_END;
197 dopt->optlen++;
198 }
199 return 0;
200 }
201
202 /*
203 * Options "fragmenting", just fill options not
204 * allowed in fragments with NOOPs.
205 * Simple and stupid 8), but the most efficient way.
206 */
207
208 void ip_options_fragment(struct sk_buff * skb)
209 {
210 unsigned char * optptr = skb->nh.raw;
211 struct ip_options * opt = &(IPCB(skb)->opt);
212 int l = opt->optlen;
213 int optlen;
214
215 while (l > 0) {
216 switch (*optptr) {
217 case IPOPT_END:
218 return;
219 case IPOPT_NOOP:
220 l--;
221 optptr++;
222 continue;
223 }
224 optlen = optptr[1];
225 if (optlen<2 || optlen>l)
226 return;
227 if (!IPOPT_COPIED(*optptr))
228 memset(optptr, IPOPT_NOOP, optlen);
229 l -= optlen;
230 optptr += optlen;
231 }
232 opt->ts = 0;
233 opt->rr = 0;
234 opt->rr_needaddr = 0;
235 opt->ts_needaddr = 0;
236 opt->ts_needtime = 0;
237 return;
238 }
239
240 /*
241 * Verify options and fill pointers in struct options.
242 * Caller should clear *opt, and set opt->data.
243 * If opt == NULL, then skb->data should point to IP header.
244 */
245
246 int ip_options_compile(struct ip_options * opt, struct sk_buff * skb)
247 {
248 int l;
249 unsigned char * iph;
250 unsigned char * optptr;
251 int optlen;
252 unsigned char * pp_ptr = NULL;
253 struct rtable *rt = skb ? (struct rtable*)skb->dst : NULL;
254
255 if (!opt) {
256 opt = &(IPCB(skb)->opt);
257 memset(opt, 0, sizeof(struct ip_options));
258 iph = skb->nh.raw;
259 opt->optlen = ((struct iphdr *)iph)->ihl*4 - sizeof(struct iphdr);
260 optptr = iph + sizeof(struct iphdr);
261 opt->is_data = 0;
262 } else {
263 optptr = opt->is_data ? opt->__data : (unsigned char*)&(skb->nh.iph[1]);
264 iph = optptr - sizeof(struct iphdr);
265 }
266
267 for (l = opt->optlen; l > 0; ) {
268 switch (*optptr) {
269 case IPOPT_END:
270 for (optptr++, l--; l>0; optptr++, l--) {
271 if (*optptr != IPOPT_END) {
272 *optptr = IPOPT_END;
273 opt->is_changed = 1;
274 }
275 }
276 goto eol;
277 case IPOPT_NOOP:
278 l--;
279 optptr++;
280 continue;
281 }
282 optlen = optptr[1];
283 if (optlen<2 || optlen>l) {
284 pp_ptr = optptr;
285 goto error;
286 }
287 switch (*optptr) {
288 case IPOPT_SSRR:
289 case IPOPT_LSRR:
290 if (optlen < 3) {
291 pp_ptr = optptr + 1;
292 goto error;
293 }
294 if (optptr[2] < 4) {
295 pp_ptr = optptr + 2;
296 goto error;
297 }
298 /* NB: cf RFC-1812 5.2.4.1 */
299 if (opt->srr) {
300 pp_ptr = optptr;
301 goto error;
302 }
303 if (!skb) {
304 if (optptr[2] != 4 || optlen < 7 || ((optlen-3) & 3)) {
305 pp_ptr = optptr + 1;
306 goto error;
307 }
308 memcpy(&opt->faddr, &optptr[3], 4);
309 if (optlen > 7)
310 memmove(&optptr[3], &optptr[7], optlen-7);
311 }
312 opt->is_strictroute = (optptr[0] == IPOPT_SSRR);
313 opt->srr = optptr - iph;
314 break;
315 case IPOPT_RR:
316 if (opt->rr) {
317 pp_ptr = optptr;
318 goto error;
319 }
320 if (optlen < 3) {
321 pp_ptr = optptr + 1;
322 goto error;
323 }
324 if (optptr[2] < 4) {
325 pp_ptr = optptr + 2;
326 goto error;
327 }
328 if (optptr[2] <= optlen) {
329 if (optptr[2]+3 > optlen) {
330 pp_ptr = optptr + 2;
331 goto error;
332 }
333 if (skb) {
334 memcpy(&optptr[optptr[2]-1], &rt->rt_spec_dst, 4);
335 opt->is_changed = 1;
336 }
337 optptr[2] += 4;
338 opt->rr_needaddr = 1;
339 }
340 opt->rr = optptr - iph;
341 break;
342 case IPOPT_TIMESTAMP:
343 if (opt->ts) {
344 pp_ptr = optptr;
345 goto error;
346 }
347 if (optlen < 4) {
348 pp_ptr = optptr + 1;
349 goto error;
350 }
351 if (optptr[2] < 5) {
352 pp_ptr = optptr + 2;
353 goto error;
354 }
355 if (optptr[2] <= optlen) {
356 __u32 * timeptr = NULL;
357 if (optptr[2]+3 > optptr[1]) {
358 pp_ptr = optptr + 2;
359 goto error;
360 }
361 switch (optptr[3]&0xF) {
362 case IPOPT_TS_TSONLY:
363 opt->ts = optptr - iph;
364 if (skb)
365 timeptr = (__u32*)&optptr[optptr[2]-1];
366 opt->ts_needtime = 1;
367 optptr[2] += 4;
368 break;
369 case IPOPT_TS_TSANDADDR:
370 if (optptr[2]+7 > optptr[1]) {
371 pp_ptr = optptr + 2;
372 goto error;
373 }
374 opt->ts = optptr - iph;
375 if (skb) {
376 memcpy(&optptr[optptr[2]-1], &rt->rt_spec_dst, 4);
377 timeptr = (__u32*)&optptr[optptr[2]+3];
378 }
379 opt->ts_needaddr = 1;
380 opt->ts_needtime = 1;
381 optptr[2] += 8;
382 break;
383 case IPOPT_TS_PRESPEC:
384 if (optptr[2]+7 > optptr[1]) {
385 pp_ptr = optptr + 2;
386 goto error;
387 }
388 opt->ts = optptr - iph;
389 {
390 u32 addr;
391 memcpy(&addr, &optptr[optptr[2]-1], 4);
392 if (inet_addr_type(addr) == RTN_UNICAST)
393 break;
394 if (skb)
395 timeptr = (__u32*)&optptr[optptr[2]+3];
396 }
397 opt->ts_needtime = 1;
398 optptr[2] += 8;
399 break;
400 default:
401 if (!skb && !capable(CAP_NET_RAW)) {
402 pp_ptr = optptr + 3;
403 goto error;
404 }
405 break;
406 }
407 if (timeptr) {
408 struct timeval tv;
409 __u32 midtime;
410 do_gettimeofday(&tv);
411 midtime = htonl((tv.tv_sec % 86400) * 1000 + tv.tv_usec / 1000);
412 memcpy(timeptr, &midtime, sizeof(__u32));
413 opt->is_changed = 1;
414 }
415 } else {
416 unsigned overflow = optptr[3]>>4;
417 if (overflow == 15) {
418 pp_ptr = optptr + 3;
419 goto error;
420 }
421 opt->ts = optptr - iph;
422 if (skb) {
423 optptr[3] = (optptr[3]&0xF)|((overflow+1)<<4);
424 opt->is_changed = 1;
425 }
426 }
427 break;
428 case IPOPT_RA:
429 if (optlen < 4) {
430 pp_ptr = optptr + 1;
431 goto error;
432 }
433 if (optptr[2] == 0 && optptr[3] == 0)
434 opt->router_alert = optptr - iph;
435 break;
436 case IPOPT_SEC:
437 case IPOPT_SID:
438 default:
439 if (!skb && !capable(CAP_NET_RAW)) {
440 pp_ptr = optptr;
441 goto error;
442 }
443 break;
444 }
445 l -= optlen;
446 optptr += optlen;
447 }
448
449 eol:
450 if (!pp_ptr)
451 return 0;
452
453 error:
454 if (skb) {
455 icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl((pp_ptr-iph)<<24));
456 }
457 return -EINVAL;
458 }
459
460
461 /*
462 * Undo all the changes done by ip_options_compile().
463 */
464
465 void ip_options_undo(struct ip_options * opt)
466 {
467 if (opt->srr) {
468 unsigned char * optptr = opt->__data+opt->srr-sizeof(struct iphdr);
469 memmove(optptr+7, optptr+3, optptr[1]-7);
470 memcpy(optptr+3, &opt->faddr, 4);
471 }
472 if (opt->rr_needaddr) {
473 unsigned char * optptr = opt->__data+opt->rr-sizeof(struct iphdr);
474 optptr[2] -= 4;
475 memset(&optptr[optptr[2]-1], 0, 4);
476 }
477 if (opt->ts) {
478 unsigned char * optptr = opt->__data+opt->ts-sizeof(struct iphdr);
479 if (opt->ts_needtime) {
480 optptr[2] -= 4;
481 memset(&optptr[optptr[2]-1], 0, 4);
482 if ((optptr[3]&0xF) == IPOPT_TS_PRESPEC)
483 optptr[2] -= 4;
484 }
485 if (opt->ts_needaddr) {
486 optptr[2] -= 4;
487 memset(&optptr[optptr[2]-1], 0, 4);
488 }
489 }
490 }
491
492 static struct ip_options *ip_options_get_alloc(const int optlen)
493 {
494 struct ip_options *opt = kmalloc(sizeof(*opt) + ((optlen + 3) & ~3),
495 GFP_KERNEL);
496 if (opt)
497 memset(opt, 0, sizeof(*opt));
498 return opt;
499 }
500
501 static int ip_options_get_finish(struct ip_options **optp,
502 struct ip_options *opt, int optlen)
503 {
504 while (optlen & 3)
505 opt->__data[optlen++] = IPOPT_END;
506 opt->optlen = optlen;
507 opt->is_data = 1;
508 opt->is_setbyuser = 1;
509 if (optlen && ip_options_compile(opt, NULL)) {
510 kfree(opt);
511 return -EINVAL;
512 }
513 if (*optp)
514 kfree(*optp);
515 *optp = opt;
516 return 0;
517 }
518
519 int ip_options_get_from_user(struct ip_options **optp, unsigned char __user *data, int optlen)
520 {
521 struct ip_options *opt = ip_options_get_alloc(optlen);
522
523 if (!opt)
524 return -ENOMEM;
525 if (optlen && copy_from_user(opt->__data, data, optlen)) {
526 kfree(opt);
527 return -EFAULT;
528 }
529 return ip_options_get_finish(optp, opt, optlen);
530 }
531
532 int ip_options_get(struct ip_options **optp, unsigned char *data, int optlen)
533 {
534 struct ip_options *opt = ip_options_get_alloc(optlen);
535
536 if (!opt)
537 return -ENOMEM;
538 if (optlen)
539 memcpy(opt->__data, data, optlen);
540 return ip_options_get_finish(optp, opt, optlen);
541 }
542
543 void ip_forward_options(struct sk_buff *skb)
544 {
545 struct ip_options * opt = &(IPCB(skb)->opt);
546 unsigned char * optptr;
547 struct rtable *rt = (struct rtable*)skb->dst;
548 unsigned char *raw = skb->nh.raw;
549
550 if (opt->rr_needaddr) {
551 optptr = (unsigned char *)raw + opt->rr;
552 ip_rt_get_source(&optptr[optptr[2]-5], rt);
553 opt->is_changed = 1;
554 }
555 if (opt->srr_is_hit) {
556 int srrptr, srrspace;
557
558 optptr = raw + opt->srr;
559
560 for ( srrptr=optptr[2], srrspace = optptr[1];
561 srrptr <= srrspace;
562 srrptr += 4
563 ) {
564 if (srrptr + 3 > srrspace)
565 break;
566 if (memcmp(&rt->rt_dst, &optptr[srrptr-1], 4) == 0)
567 break;
568 }
569 if (srrptr + 3 <= srrspace) {
570 opt->is_changed = 1;
571 ip_rt_get_source(&optptr[srrptr-1], rt);
572 skb->nh.iph->daddr = rt->rt_dst;
573 optptr[2] = srrptr+4;
574 } else if (net_ratelimit())
575 printk(KERN_CRIT "ip_forward(): Argh! Destination lost!\n");
576 if (opt->ts_needaddr) {
577 optptr = raw + opt->ts;
578 ip_rt_get_source(&optptr[optptr[2]-9], rt);
579 opt->is_changed = 1;
580 }
581 }
582 if (opt->is_changed) {
583 opt->is_changed = 0;
584 ip_send_check(skb->nh.iph);
585 }
586 }
587
588 int ip_options_rcv_srr(struct sk_buff *skb)
589 {
590 struct ip_options *opt = &(IPCB(skb)->opt);
591 int srrspace, srrptr;
592 u32 nexthop;
593 struct iphdr *iph = skb->nh.iph;
594 unsigned char * optptr = skb->nh.raw + opt->srr;
595 struct rtable *rt = (struct rtable*)skb->dst;
596 struct rtable *rt2;
597 int err;
598
599 if (!opt->srr)
600 return 0;
601
602 if (skb->pkt_type != PACKET_HOST)
603 return -EINVAL;
604 if (rt->rt_type == RTN_UNICAST) {
605 if (!opt->is_strictroute)
606 return 0;
607 icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl(16<<24));
608 return -EINVAL;
609 }
610 if (rt->rt_type != RTN_LOCAL)
611 return -EINVAL;
612
613 for (srrptr=optptr[2], srrspace = optptr[1]; srrptr <= srrspace; srrptr += 4) {
614 if (srrptr + 3 > srrspace) {
615 icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl((opt->srr+2)<<24));
616 return -EINVAL;
617 }
618 memcpy(&nexthop, &optptr[srrptr-1], 4);
619
620 rt = (struct rtable*)skb->dst;
621 skb->dst = NULL;
622 err = ip_route_input(skb, nexthop, iph->saddr, iph->tos, skb->dev);
623 rt2 = (struct rtable*)skb->dst;
624 if (err || (rt2->rt_type != RTN_UNICAST && rt2->rt_type != RTN_LOCAL)) {
625 ip_rt_put(rt2);
626 skb->dst = &rt->u.dst;
627 return -EINVAL;
628 }
629 ip_rt_put(rt);
630 if (rt2->rt_type != RTN_LOCAL)
631 break;
632 /* Superfast 8) loopback forward */
633 memcpy(&iph->daddr, &optptr[srrptr-1], 4);
634 opt->is_changed = 1;
635 }
636 if (srrptr <= srrspace) {
637 opt->srr_is_hit = 1;
638 opt->is_changed = 1;
639 }
640 return 0;
641 }
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