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[dragonfly.git] / sys / net / pf / pf_norm.c
blob7f5ca8699bba1db0b18dac7f7c5247186035829f
1 /* $OpenBSD: pf_norm.c,v 1.113 2008/05/07 07:07:29 markus Exp $ */
2
3 /*
4 * Copyright (c) 2010 The DragonFly Project. All rights reserved.
5 *
6 * Copyright 2001 Niels Provos <provos@citi.umich.edu>
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30 #include "opt_inet.h"
31 #include "opt_inet6.h"
32
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/mbuf.h>
36 #include <sys/filio.h>
37 #include <sys/fcntl.h>
38 #include <sys/socket.h>
39 #include <sys/kernel.h>
40 #include <sys/time.h>
41
42 #include <net/if.h>
43 #include <net/if_types.h>
44 #include <net/bpf.h>
45 #include <net/route.h>
46 #include <net/pf/if_pflog.h>
47
48 #include <netinet/in.h>
49 #include <netinet/in_var.h>
50 #include <netinet/in_systm.h>
51 #include <netinet/ip.h>
52 #include <netinet/ip_var.h>
53 #include <netinet/tcp.h>
54 #include <netinet/tcp_seq.h>
55 #include <netinet/udp.h>
56 #include <netinet/ip_icmp.h>
57
58 #ifdef INET6
59 #include <netinet/ip6.h>
60 #endif /* INET6 */
61
62 #include <net/pf/pfvar.h>
63
64 #define PFFRAG_SEENLAST 0x0001 /* Seen the last fragment for this */
65 #define PFFRAG_NOBUFFER 0x0002 /* Non-buffering fragment cache */
66 #define PFFRAG_DROP 0x0004 /* Drop all fragments */
67 #define BUFFER_FRAGMENTS(fr) (!((fr)->fr_flags & PFFRAG_NOBUFFER))
68
69
70 TAILQ_HEAD(pf_fragqueue, pf_fragment) pf_fragqueue[MAXCPU];
71 TAILQ_HEAD(pf_cachequeue, pf_fragment) pf_cachequeue[MAXCPU];
72
73 static __inline int pf_frag_compare(struct pf_fragment *,
74 struct pf_fragment *);
75 RB_HEAD(pf_frag_tree, pf_fragment) pf_frag_tree[MAXCPU],
76 pf_cache_tree[MAXCPU];
77 RB_PROTOTYPE(pf_frag_tree, pf_fragment, fr_entry, pf_frag_compare);
78 RB_GENERATE(pf_frag_tree, pf_fragment, fr_entry, pf_frag_compare);
79
80 /* Private prototypes */
81 void pf_ip2key(struct pf_fragment *, struct ip *);
82 void pf_remove_fragment(struct pf_fragment *);
83 void pf_flush_fragments(void);
84 void pf_free_fragment(struct pf_fragment *);
85 struct pf_fragment *pf_find_fragment(struct ip *, struct pf_frag_tree *);
86 struct mbuf *pf_reassemble(struct mbuf **, struct pf_fragment **,
87 struct pf_frent *, int);
88 struct mbuf *pf_fragcache(struct mbuf **, struct ip*,
89 struct pf_fragment **, int, int, int *);
90 int pf_normalize_tcpopt(struct pf_rule *, struct mbuf *,
91 struct tcphdr *, int, sa_family_t);
92
93 #define DPFPRINTF(x) do { \
94 if (pf_status.debug >= PF_DEBUG_MISC) { \
95 kprintf("%s: ", __func__); \
96 kprintf x ; \
97 } \
98 } while(0)
99
100 static MALLOC_DEFINE(M_PFFRAGPL, "pffrag", "pf fragment pool list");
101 static MALLOC_DEFINE(M_PFCACHEPL, "pffrcache", "pf fragment cache pool list");
102 static MALLOC_DEFINE(M_PFFRENTPL, "pffrent", "pf frent pool list");
103 static MALLOC_DEFINE(M_PFCENTPL, "pffrcent", "pf fragment cent pool list");
104 static MALLOC_DEFINE(M_PFSTATESCRUBPL, "pfstatescrub", "pf state scrub pool list");
105
106 /* Globals */
107 struct malloc_type *pf_frent_pl, *pf_frag_pl, *pf_cache_pl, *pf_cent_pl;
108 struct malloc_type *pf_state_scrub_pl;
109 int pf_nfrents, pf_ncache;
110
111 void
112 pf_normalize_init(void)
113 {
114 int n;
115
116 /* XXX
117 pool_sethiwat(&pf_frag_pl, PFFRAG_FRAG_HIWAT);
118 pool_sethardlimit(&pf_frent_pl, PFFRAG_FRENT_HIWAT, NULL, 0);
119 pool_sethardlimit(&pf_cache_pl, PFFRAG_FRCACHE_HIWAT, NULL, 0);
120 pool_sethardlimit(&pf_cent_pl, PFFRAG_FRCENT_HIWAT, NULL, 0);
121 */
122
123 for (n = 0; n < MAXCPU; ++n) {
124 TAILQ_INIT(&pf_fragqueue[n]);
125 TAILQ_INIT(&pf_cachequeue[n]);
126 RB_INIT(&pf_frag_tree[n]);
127 RB_INIT(&pf_cache_tree[n]);
128 }
129 }
130
131 static __inline int
132 pf_frag_compare(struct pf_fragment *a, struct pf_fragment *b)
133 {
134 int diff;
135
136 if ((diff = a->fr_id - b->fr_id))
137 return (diff);
138 else if ((diff = a->fr_p - b->fr_p))
139 return (diff);
140 else if (a->fr_src.s_addr < b->fr_src.s_addr)
141 return (-1);
142 else if (a->fr_src.s_addr > b->fr_src.s_addr)
143 return (1);
144 else if (a->fr_dst.s_addr < b->fr_dst.s_addr)
145 return (-1);
146 else if (a->fr_dst.s_addr > b->fr_dst.s_addr)
147 return (1);
148 return (0);
149 }
150
151 void
152 pf_purge_expired_fragments(void)
153 {
154 struct pf_fragment *frag;
155 u_int32_t expire;
156 int cpu = mycpu->gd_cpuid;
157
158 expire = time_second - pf_default_rule.timeout[PFTM_FRAG];
159
160 while ((frag = TAILQ_LAST(&pf_fragqueue[cpu], pf_fragqueue)) != NULL) {
161 KASSERT((BUFFER_FRAGMENTS(frag)),
162 ("BUFFER_FRAGMENTS(frag) == 0: %s", __func__));
163 if (frag->fr_timeout > expire)
164 break;
165
166 DPFPRINTF(("expiring %d(%p)\n", frag->fr_id, frag));
167 pf_free_fragment(frag);
168 }
169
170 while ((frag = TAILQ_LAST(&pf_cachequeue[cpu], pf_cachequeue)) != NULL) {
171 KASSERT((!BUFFER_FRAGMENTS(frag)),
172 ("BUFFER_FRAGMENTS(frag) != 0: %s", __func__));
173 if (frag->fr_timeout > expire)
174 break;
175
176 DPFPRINTF(("expiring %d(%p)\n", frag->fr_id, frag));
177 pf_free_fragment(frag);
178 KASSERT((TAILQ_EMPTY(&pf_cachequeue[cpu]) ||
179 TAILQ_LAST(&pf_cachequeue[cpu], pf_cachequeue) != frag),
180 ("!(TAILQ_EMPTY() || TAILQ_LAST() == farg): %s",
181 __func__));
182 }
183 }
184
185 /*
186 * Try to flush old fragments to make space for new ones
187 */
188
189 void
190 pf_flush_fragments(void)
191 {
192 struct pf_fragment *frag;
193 int goal;
194 int cpu = mycpu->gd_cpuid;
195
196 goal = pf_nfrents * 9 / 10;
197 DPFPRINTF(("trying to free > %d frents\n",
198 pf_nfrents - goal));
199 while (goal < pf_nfrents) {
200 frag = TAILQ_LAST(&pf_fragqueue[cpu], pf_fragqueue);
201 if (frag == NULL)
202 break;
203 pf_free_fragment(frag);
204 }
205
206
207 goal = pf_ncache * 9 / 10;
208 DPFPRINTF(("trying to free > %d cache entries\n",
209 pf_ncache - goal));
210 while (goal < pf_ncache) {
211 frag = TAILQ_LAST(&pf_cachequeue[cpu], pf_cachequeue);
212 if (frag == NULL)
213 break;
214 pf_free_fragment(frag);
215 }
216 }
217
218 /* Frees the fragments and all associated entries */
219
220 void
221 pf_free_fragment(struct pf_fragment *frag)
222 {
223 struct pf_frent *frent;
224 struct pf_frcache *frcache;
225
226 /* Free all fragments */
227 if (BUFFER_FRAGMENTS(frag)) {
228 for (frent = LIST_FIRST(&frag->fr_queue); frent;
229 frent = LIST_FIRST(&frag->fr_queue)) {
230 LIST_REMOVE(frent, fr_next);
231
232 m_freem(frent->fr_m);
233 kfree(frent, M_PFFRENTPL);
234 pf_nfrents--;
235 }
236 } else {
237 for (frcache = LIST_FIRST(&frag->fr_cache); frcache;
238 frcache = LIST_FIRST(&frag->fr_cache)) {
239 LIST_REMOVE(frcache, fr_next);
240
241 KASSERT((LIST_EMPTY(&frag->fr_cache) ||
242 LIST_FIRST(&frag->fr_cache)->fr_off >
243 frcache->fr_end),
244 ("! (LIST_EMPTY() || LIST_FIRST()->fr_off >"
245 " frcache->fr_end): %s", __func__));
246
247 kfree(frcache, M_PFCENTPL);
248 pf_ncache--;
249 }
250 }
251
252 pf_remove_fragment(frag);
253 }
254
255 void
256 pf_ip2key(struct pf_fragment *key, struct ip *ip)
257 {
258 key->fr_p = ip->ip_p;
259 key->fr_id = ip->ip_id;
260 key->fr_src.s_addr = ip->ip_src.s_addr;
261 key->fr_dst.s_addr = ip->ip_dst.s_addr;
262 }
263
264 struct pf_fragment *
265 pf_find_fragment(struct ip *ip, struct pf_frag_tree *tree)
266 {
267 struct pf_fragment key;
268 struct pf_fragment *frag;
269 int cpu = mycpu->gd_cpuid;
270
271 pf_ip2key(&key, ip);
272
273 frag = RB_FIND(pf_frag_tree, tree, &key);
274 if (frag != NULL) {
275 /* XXX Are we sure we want to update the timeout? */
276 frag->fr_timeout = time_second;
277 if (BUFFER_FRAGMENTS(frag)) {
278 TAILQ_REMOVE(&pf_fragqueue[cpu], frag, frag_next);
279 TAILQ_INSERT_HEAD(&pf_fragqueue[cpu], frag, frag_next);
280 } else {
281 TAILQ_REMOVE(&pf_cachequeue[cpu], frag, frag_next);
282 TAILQ_INSERT_HEAD(&pf_cachequeue[cpu], frag, frag_next);
283 }
284 }
285
286 return (frag);
287 }
288
289 /* Removes a fragment from the fragment queue and frees the fragment */
290
291 void
292 pf_remove_fragment(struct pf_fragment *frag)
293 {
294 int cpu = mycpu->gd_cpuid;
295
296 if (BUFFER_FRAGMENTS(frag)) {
297 RB_REMOVE(pf_frag_tree, &pf_frag_tree[cpu], frag);
298 TAILQ_REMOVE(&pf_fragqueue[cpu], frag, frag_next);
299 kfree(frag, M_PFFRAGPL);
300 } else {
301 RB_REMOVE(pf_frag_tree, &pf_cache_tree[cpu], frag);
302 TAILQ_REMOVE(&pf_cachequeue[cpu], frag, frag_next);
303 kfree(frag, M_PFCACHEPL);
304 }
305 }
306
307 #define FR_IP_OFF(fr) (((fr)->fr_ip->ip_off & IP_OFFMASK) << 3)
308 struct mbuf *
309 pf_reassemble(struct mbuf **m0, struct pf_fragment **frag,
310 struct pf_frent *frent, int mff)
311 {
312 struct mbuf *m = *m0, *m2;
313 struct pf_frent *frea, *next;
314 struct pf_frent *frep = NULL;
315 struct ip *ip = frent->fr_ip;
316 int hlen = ip->ip_hl << 2;
317 u_int16_t off = (ip->ip_off & IP_OFFMASK) << 3;
318 u_int16_t ip_len = ip->ip_len - ip->ip_hl * 4;
319 u_int16_t max = ip_len + off;
320 int cpu = mycpu->gd_cpuid;
321
322 KASSERT((*frag == NULL || BUFFER_FRAGMENTS(*frag)),
323 ("! (*frag == NULL || BUFFER_FRAGMENTS(*frag)): %s", __func__));
324
325 /* Strip off ip header */
326 m->m_data += hlen;
327 m->m_len -= hlen;
328
329 /* Create a new reassembly queue for this packet */
330 if (*frag == NULL) {
331 *frag = kmalloc(sizeof(struct pf_fragment), M_PFFRAGPL, M_NOWAIT);
332 if (*frag == NULL) {
333 pf_flush_fragments();
334 *frag = kmalloc(sizeof(struct pf_fragment), M_PFFRAGPL, M_NOWAIT);
335 if (*frag == NULL)
336 goto drop_fragment;
337 }
338
339 (*frag)->fr_flags = 0;
340 (*frag)->fr_max = 0;
341 (*frag)->fr_src = frent->fr_ip->ip_src;
342 (*frag)->fr_dst = frent->fr_ip->ip_dst;
343 (*frag)->fr_p = frent->fr_ip->ip_p;
344 (*frag)->fr_id = frent->fr_ip->ip_id;
345 (*frag)->fr_timeout = time_second;
346 LIST_INIT(&(*frag)->fr_queue);
347
348 RB_INSERT(pf_frag_tree, &pf_frag_tree[cpu], *frag);
349 TAILQ_INSERT_HEAD(&pf_fragqueue[cpu], *frag, frag_next);
350
351 /* We do not have a previous fragment */
352 frep = NULL;
353 goto insert;
354 }
355
356 /*
357 * Find a fragment after the current one:
358 * - off contains the real shifted offset.
359 */
360 LIST_FOREACH(frea, &(*frag)->fr_queue, fr_next) {
361 if (FR_IP_OFF(frea) > off)
362 break;
363 frep = frea;
364 }
365
366 KASSERT((frep != NULL || frea != NULL),
367 ("!(frep != NULL || frea != NULL): %s", __func__));
368
369 if (frep != NULL &&
370 FR_IP_OFF(frep) + frep->fr_ip->ip_len - frep->fr_ip->ip_hl *
371 4 > off)
372 {
373 u_int16_t precut;
374
375 precut = FR_IP_OFF(frep) + frep->fr_ip->ip_len -
376 frep->fr_ip->ip_hl * 4 - off;
377 if (precut >= ip_len)
378 goto drop_fragment;
379 m_adj(frent->fr_m, precut);
380 DPFPRINTF(("overlap -%d\n", precut));
381 /* Enforce 8 byte boundaries */
382 ip->ip_off = ip->ip_off + (precut >> 3);
383 off = (ip->ip_off & IP_OFFMASK) << 3;
384 ip_len -= precut;
385 ip->ip_len = ip_len;
386 }
387
388 for (; frea != NULL && ip_len + off > FR_IP_OFF(frea);
389 frea = next)
390 {
391 u_int16_t aftercut;
392
393 aftercut = ip_len + off - FR_IP_OFF(frea);
394 DPFPRINTF(("adjust overlap %d\n", aftercut));
395 if (aftercut < frea->fr_ip->ip_len - frea->fr_ip->ip_hl
396 * 4)
397 {
398 frea->fr_ip->ip_len =
399 frea->fr_ip->ip_len - aftercut;
400 frea->fr_ip->ip_off = frea->fr_ip->ip_off +
401 (aftercut >> 3);
402 m_adj(frea->fr_m, aftercut);
403 break;
404 }
405
406 /* This fragment is completely overlapped, lose it */
407 next = LIST_NEXT(frea, fr_next);
408 m_freem(frea->fr_m);
409 LIST_REMOVE(frea, fr_next);
410 kfree(frea, M_PFFRENTPL);
411 pf_nfrents--;
412 }
413
414 insert:
415 /* Update maximum data size */
416 if ((*frag)->fr_max < max)
417 (*frag)->fr_max = max;
418 /* This is the last segment */
419 if (!mff)
420 (*frag)->fr_flags |= PFFRAG_SEENLAST;
421
422 if (frep == NULL)
423 LIST_INSERT_HEAD(&(*frag)->fr_queue, frent, fr_next);
424 else
425 LIST_INSERT_AFTER(frep, frent, fr_next);
426
427 /* Check if we are completely reassembled */
428 if (!((*frag)->fr_flags & PFFRAG_SEENLAST))
429 return (NULL);
430
431 /* Check if we have all the data */
432 off = 0;
433 for (frep = LIST_FIRST(&(*frag)->fr_queue); frep; frep = next) {
434 next = LIST_NEXT(frep, fr_next);
435
436 off += frep->fr_ip->ip_len - frep->fr_ip->ip_hl * 4;
437 if (off < (*frag)->fr_max &&
438 (next == NULL || FR_IP_OFF(next) != off))
439 {
440 DPFPRINTF(("missing fragment at %d, next %d, max %d\n",
441 off, next == NULL ? -1 : FR_IP_OFF(next),
442 (*frag)->fr_max));
443 return (NULL);
444 }
445 }
446 DPFPRINTF(("%d < %d?\n", off, (*frag)->fr_max));
447 if (off < (*frag)->fr_max)
448 return (NULL);
449
450 /* We have all the data */
451 frent = LIST_FIRST(&(*frag)->fr_queue);
452 KASSERT((frent != NULL), ("frent == NULL: %s", __func__));
453 if ((frent->fr_ip->ip_hl << 2) + off > IP_MAXPACKET) {
454 DPFPRINTF(("drop: too big: %d\n", off));
455 pf_free_fragment(*frag);
456 *frag = NULL;
457 return (NULL);
458 }
459 next = LIST_NEXT(frent, fr_next);
460
461 /* Magic from ip_input */
462 ip = frent->fr_ip;
463 m = frent->fr_m;
464 m2 = m->m_next;
465 m->m_next = NULL;
466 m_cat(m, m2);
467 kfree(frent, M_PFFRENTPL);
468 pf_nfrents--;
469 for (frent = next; frent != NULL; frent = next) {
470 next = LIST_NEXT(frent, fr_next);
471
472 m2 = frent->fr_m;
473 kfree(frent, M_PFFRENTPL);
474 pf_nfrents--;
475 m_cat(m, m2);
476 }
477
478 ip->ip_src = (*frag)->fr_src;
479 ip->ip_dst = (*frag)->fr_dst;
480
481 /* Remove from fragment queue */
482 pf_remove_fragment(*frag);
483 *frag = NULL;
484
485 hlen = ip->ip_hl << 2;
486 ip->ip_len = off + hlen;
487 m->m_len += hlen;
488 m->m_data -= hlen;
489
490 /* some debugging cruft by sklower, below, will go away soon */
491 /* XXX this should be done elsewhere */
492 if (m->m_flags & M_PKTHDR) {
493 int plen = 0;
494 for (m2 = m; m2; m2 = m2->m_next)
495 plen += m2->m_len;
496 m->m_pkthdr.len = plen;
497 }
498
499 DPFPRINTF(("complete: %p(%d)\n", m, ip->ip_len));
500 return (m);
501
502 drop_fragment:
503 /* Oops - fail safe - drop packet */
504 kfree(frent, M_PFFRENTPL);
505 pf_nfrents--;
506 m_freem(m);
507 return (NULL);
508 }
509
510 struct mbuf *
511 pf_fragcache(struct mbuf **m0, struct ip *h, struct pf_fragment **frag, int mff,
512 int drop, int *nomem)
513 {
514 struct mbuf *m = *m0;
515 struct pf_frcache *frp, *fra, *cur = NULL;
516 int ip_len = h->ip_len - (h->ip_hl << 2);
517 u_int16_t off = h->ip_off << 3;
518 u_int16_t max = ip_len + off;
519 int hosed = 0;
520 int cpu = mycpu->gd_cpuid;
521
522 KASSERT((*frag == NULL || !BUFFER_FRAGMENTS(*frag)),
523 ("!(*frag == NULL || !BUFFER_FRAGMENTS(*frag)): %s", __func__));
524
525 /* Create a new range queue for this packet */
526 if (*frag == NULL) {
527 *frag = kmalloc(sizeof(struct pf_fragment), M_PFCACHEPL, M_NOWAIT);
528 if (*frag == NULL) {
529 pf_flush_fragments();
530 *frag = kmalloc(sizeof(struct pf_fragment), M_PFCACHEPL, M_NOWAIT);
531 if (*frag == NULL)
532 goto no_mem;
533 }
534
535 /* Get an entry for the queue */
536 cur = kmalloc(sizeof(struct pf_frcache), M_PFCENTPL, M_NOWAIT);
537 if (cur == NULL) {
538 kfree(*frag, M_PFCACHEPL);
539 *frag = NULL;
540 goto no_mem;
541 }
542 pf_ncache++;
543
544 (*frag)->fr_flags = PFFRAG_NOBUFFER;
545 (*frag)->fr_max = 0;
546 (*frag)->fr_src = h->ip_src;
547 (*frag)->fr_dst = h->ip_dst;
548 (*frag)->fr_p = h->ip_p;
549 (*frag)->fr_id = h->ip_id;
550 (*frag)->fr_timeout = time_second;
551
552 cur->fr_off = off;
553 cur->fr_end = max;
554 LIST_INIT(&(*frag)->fr_cache);
555 LIST_INSERT_HEAD(&(*frag)->fr_cache, cur, fr_next);
556
557 RB_INSERT(pf_frag_tree, &pf_cache_tree[cpu], *frag);
558 TAILQ_INSERT_HEAD(&pf_cachequeue[cpu], *frag, frag_next);
559
560 DPFPRINTF(("fragcache[%d]: new %d-%d\n", h->ip_id, off, max));
561
562 goto pass;
563 }
564
565 /*
566 * Find a fragment after the current one:
567 * - off contains the real shifted offset.
568 */
569 frp = NULL;
570 LIST_FOREACH(fra, &(*frag)->fr_cache, fr_next) {
571 if (fra->fr_off > off)
572 break;
573 frp = fra;
574 }
575
576 KASSERT((frp != NULL || fra != NULL),
577 ("!(frp != NULL || fra != NULL): %s", __func__));
578
579 if (frp != NULL) {
580 int precut;
581
582 precut = frp->fr_end - off;
583 if (precut >= ip_len) {
584 /* Fragment is entirely a duplicate */
585 DPFPRINTF(("fragcache[%d]: dead (%d-%d) %d-%d\n",
586 h->ip_id, frp->fr_off, frp->fr_end, off, max));
587 goto drop_fragment;
588 }
589 if (precut == 0) {
590 /* They are adjacent. Fixup cache entry */
591 DPFPRINTF(("fragcache[%d]: adjacent (%d-%d) %d-%d\n",
592 h->ip_id, frp->fr_off, frp->fr_end, off, max));
593 frp->fr_end = max;
594 } else if (precut > 0) {
595 /* The first part of this payload overlaps with a
596 * fragment that has already been passed.
597 * Need to trim off the first part of the payload.
598 * But to do so easily, we need to create another
599 * mbuf to throw the original header into.
600 */
601
602 DPFPRINTF(("fragcache[%d]: chop %d (%d-%d) %d-%d\n",
603 h->ip_id, precut, frp->fr_off, frp->fr_end, off,
604 max));
605
606 off += precut;
607 max -= precut;
608 /* Update the previous frag to encompass this one */
609 frp->fr_end = max;
610
611 if (!drop) {
612 /* XXX Optimization opportunity
613 * This is a very heavy way to trim the payload.
614 * we could do it much faster by diddling mbuf
615 * internals but that would be even less legible
616 * than this mbuf magic. For my next trick,
617 * I'll pull a rabbit out of my laptop.
618 */
619 *m0 = m_dup(m, M_NOWAIT);
620 /* From KAME Project : We have missed this! */
621 m_adj(*m0, (h->ip_hl << 2) -
622 (*m0)->m_pkthdr.len);
623 if (*m0 == NULL)
624 goto no_mem;
625 KASSERT(((*m0)->m_next == NULL),
626 ("(*m0)->m_next != NULL: %s",
627 __func__));
628 m_adj(m, precut + (h->ip_hl << 2));
629 m_cat(*m0, m);
630 m = *m0;
631 if (m->m_flags & M_PKTHDR) {
632 int plen = 0;
633 struct mbuf *t;
634 for (t = m; t; t = t->m_next)
635 plen += t->m_len;
636 m->m_pkthdr.len = plen;
637 }
638
639
640 h = mtod(m, struct ip *);
641
642 KASSERT(((int)m->m_len ==
643 h->ip_len - precut),
644 ("m->m_len != h->ip_len - precut: %s",
645 __func__));
646 h->ip_off = h->ip_off +
647 (precut >> 3);
648 h->ip_len = h->ip_len - precut;
649 } else {
650 hosed++;
651 }
652 } else {
653 /* There is a gap between fragments */
654
655 DPFPRINTF(("fragcache[%d]: gap %d (%d-%d) %d-%d\n",
656 h->ip_id, -precut, frp->fr_off, frp->fr_end, off,
657 max));
658
659 cur = kmalloc(sizeof(struct pf_frcache), M_PFCENTPL, M_NOWAIT);
660 if (cur == NULL)
661 goto no_mem;
662 pf_ncache++;
663
664 cur->fr_off = off;
665 cur->fr_end = max;
666 LIST_INSERT_AFTER(frp, cur, fr_next);
667 }
668 }
669
670 if (fra != NULL) {
671 int aftercut;
672 int merge = 0;
673
674 aftercut = max - fra->fr_off;
675 if (aftercut == 0) {
676 /* Adjacent fragments */
677 DPFPRINTF(("fragcache[%d]: adjacent %d-%d (%d-%d)\n",
678 h->ip_id, off, max, fra->fr_off, fra->fr_end));
679 fra->fr_off = off;
680 merge = 1;
681 } else if (aftercut > 0) {
682 /* Need to chop off the tail of this fragment */
683 DPFPRINTF(("fragcache[%d]: chop %d %d-%d (%d-%d)\n",
684 h->ip_id, aftercut, off, max, fra->fr_off,
685 fra->fr_end));
686 fra->fr_off = off;
687 max -= aftercut;
688
689 merge = 1;
690
691 if (!drop) {
692 m_adj(m, -aftercut);
693 if (m->m_flags & M_PKTHDR) {
694 int plen = 0;
695 struct mbuf *t;
696 for (t = m; t; t = t->m_next)
697 plen += t->m_len;
698 m->m_pkthdr.len = plen;
699 }
700 h = mtod(m, struct ip *);
701 KASSERT(((int)m->m_len == h->ip_len - aftercut),
702 ("m->m_len != h->ip_len - aftercut: %s",
703 __func__));
704 h->ip_len = h->ip_len - aftercut;
705 } else {
706 hosed++;
707 }
708 } else if (frp == NULL) {
709 /* There is a gap between fragments */
710 DPFPRINTF(("fragcache[%d]: gap %d %d-%d (%d-%d)\n",
711 h->ip_id, -aftercut, off, max, fra->fr_off,
712 fra->fr_end));
713
714 cur = kmalloc(sizeof(struct pf_frcache), M_PFCENTPL, M_NOWAIT);
715 if (cur == NULL)
716 goto no_mem;
717 pf_ncache++;
718
719 cur->fr_off = off;
720 cur->fr_end = max;
721 LIST_INSERT_BEFORE(fra, cur, fr_next);
722 }
723
724
725 /* Need to glue together two separate fragment descriptors */
726 if (merge) {
727 if (cur && fra->fr_off <= cur->fr_end) {
728 /* Need to merge in a previous 'cur' */
729 DPFPRINTF(("fragcache[%d]: adjacent(merge "
730 "%d-%d) %d-%d (%d-%d)\n",
731 h->ip_id, cur->fr_off, cur->fr_end, off,
732 max, fra->fr_off, fra->fr_end));
733 fra->fr_off = cur->fr_off;
734 LIST_REMOVE(cur, fr_next);
735 kfree(cur, M_PFCENTPL);
736 pf_ncache--;
737 cur = NULL;
738
739 } else if (frp && fra->fr_off <= frp->fr_end) {
740 /* Need to merge in a modified 'frp' */
741 KASSERT((cur == NULL), ("cur != NULL: %s",
742 __func__));
743 DPFPRINTF(("fragcache[%d]: adjacent(merge "
744 "%d-%d) %d-%d (%d-%d)\n",
745 h->ip_id, frp->fr_off, frp->fr_end, off,
746 max, fra->fr_off, fra->fr_end));
747 fra->fr_off = frp->fr_off;
748 LIST_REMOVE(frp, fr_next);
749 kfree(frp, M_PFCENTPL);
750 pf_ncache--;
751 frp = NULL;
752
753 }
754 }
755 }
756
757 if (hosed) {
758 /*
759 * We must keep tracking the overall fragment even when
760 * we're going to drop it anyway so that we know when to
761 * free the overall descriptor. Thus we drop the frag late.
762 */
763 goto drop_fragment;
764 }
765
766
767 pass:
768 /* Update maximum data size */
769 if ((*frag)->fr_max < max)
770 (*frag)->fr_max = max;
771
772 /* This is the last segment */
773 if (!mff)
774 (*frag)->fr_flags |= PFFRAG_SEENLAST;
775
776 /* Check if we are completely reassembled */
777 if (((*frag)->fr_flags & PFFRAG_SEENLAST) &&
778 LIST_FIRST(&(*frag)->fr_cache)->fr_off == 0 &&
779 LIST_FIRST(&(*frag)->fr_cache)->fr_end == (*frag)->fr_max) {
780 /* Remove from fragment queue */
781 DPFPRINTF(("fragcache[%d]: done 0-%d\n", h->ip_id,
782 (*frag)->fr_max));
783 pf_free_fragment(*frag);
784 *frag = NULL;
785 }
786
787 return (m);
788
789 no_mem:
790 *nomem = 1;
791
792 /* Still need to pay attention to !IP_MF */
793 if (!mff && *frag != NULL)
794 (*frag)->fr_flags |= PFFRAG_SEENLAST;
795
796 m_freem(m);
797 return (NULL);
798
799 drop_fragment:
800
801 /* Still need to pay attention to !IP_MF */
802 if (!mff && *frag != NULL)
803 (*frag)->fr_flags |= PFFRAG_SEENLAST;
804
805 if (drop) {
806 /* This fragment has been deemed bad. Don't reass */
807 if (((*frag)->fr_flags & PFFRAG_DROP) == 0)
808 DPFPRINTF(("fragcache[%d]: dropping overall fragment\n",
809 h->ip_id));
810 (*frag)->fr_flags |= PFFRAG_DROP;
811 }
812
813 m_freem(m);
814 return (NULL);
815 }
816
817 int
818 pf_normalize_ip(struct mbuf **m0, int dir, struct pfi_kif *kif, u_short *reason,
819 struct pf_pdesc *pd)
820 {
821 struct mbuf *m = *m0;
822 struct pf_rule *r;
823 struct pf_frent *frent;
824 struct pf_fragment *frag = NULL;
825 struct ip *h = mtod(m, struct ip *);
826 int mff = (h->ip_off & IP_MF);
827 int hlen = h->ip_hl << 2;
828 u_int16_t fragoff = (h->ip_off & IP_OFFMASK) << 3;
829 u_int16_t max;
830 int ip_len;
831 int tag = -1;
832 int cpu = mycpu->gd_cpuid;
833
834 r = TAILQ_FIRST(pf_main_ruleset.rules[PF_RULESET_SCRUB].active.ptr);
835 while (r != NULL) {
836 r->evaluations++;
837 if (pfi_kif_match(r->kif, kif) == r->ifnot)
838 r = r->skip[PF_SKIP_IFP].ptr;
839 else if (r->direction && r->direction != dir)
840 r = r->skip[PF_SKIP_DIR].ptr;
841 else if (r->af && r->af != AF_INET)
842 r = r->skip[PF_SKIP_AF].ptr;
843 else if (r->proto && r->proto != h->ip_p)
844 r = r->skip[PF_SKIP_PROTO].ptr;
845 else if (PF_MISMATCHAW(&r->src.addr,
846 (struct pf_addr *)&h->ip_src.s_addr, AF_INET,
847 r->src.neg, kif))
848 r = r->skip[PF_SKIP_SRC_ADDR].ptr;
849 else if (PF_MISMATCHAW(&r->dst.addr,
850 (struct pf_addr *)&h->ip_dst.s_addr, AF_INET,
851 r->dst.neg, NULL))
852 r = r->skip[PF_SKIP_DST_ADDR].ptr;
853 else if (r->match_tag && !pf_match_tag(m, r, &tag))
854 r = TAILQ_NEXT(r, entries);
855 else
856 break;
857 }
858
859 if (r == NULL || r->action == PF_NOSCRUB)
860 return (PF_PASS);
861 else {
862 r->packets[dir == PF_OUT]++;
863 r->bytes[dir == PF_OUT] += pd->tot_len;
864 }
865
866 /* Check for illegal packets */
867 if (hlen < (int)sizeof(struct ip))
868 goto drop;
869
870 if (hlen > h->ip_len)
871 goto drop;
872
873 /* Clear IP_DF if the rule uses the no-df option */
874 if (r->rule_flag & PFRULE_NODF && h->ip_off & IP_DF) {
875 u_int16_t ip_off = h->ip_off;
876
877 h->ip_off &= ~IP_DF;
878 h->ip_sum = pf_cksum_fixup(h->ip_sum, ip_off, h->ip_off, 0);
879 }
880
881 /* We will need other tests here */
882 if (!fragoff && !mff)
883 goto no_fragment;
884
885 /* A fragment; rehash required. */
886 m->m_flags &= ~M_HASH;
887
888 /* We're dealing with a fragment now. Don't allow fragments
889 * with IP_DF to enter the cache. If the flag was cleared by
890 * no-df above, fine. Otherwise drop it.
891 */
892 if (h->ip_off & IP_DF) {
893 DPFPRINTF(("IP_DF\n"));
894 goto bad;
895 }
896
897 ip_len = h->ip_len - hlen;
898
899 /* All fragments are 8 byte aligned */
900 if (mff && (ip_len & 0x7)) {
901 DPFPRINTF(("mff and %d\n", ip_len));
902 goto bad;
903 }
904
905 /* Respect maximum length */
906 if (fragoff + ip_len > IP_MAXPACKET) {
907 DPFPRINTF(("max packet %d\n", fragoff + ip_len));
908 goto bad;
909 }
910 max = fragoff + ip_len;
911
912 if ((r->rule_flag & (PFRULE_FRAGCROP|PFRULE_FRAGDROP)) == 0) {
913 /* Fully buffer all of the fragments */
914
915 frag = pf_find_fragment(h, &pf_frag_tree[cpu]);
916
917 /* Check if we saw the last fragment already */
918 if (frag != NULL && (frag->fr_flags & PFFRAG_SEENLAST) &&
919 max > frag->fr_max)
920 goto bad;
921
922 /* Get an entry for the fragment queue */
923 frent = kmalloc(sizeof(struct pf_frent), M_PFFRENTPL, M_NOWAIT);
924 if (frent == NULL) {
925 REASON_SET(reason, PFRES_MEMORY);
926 return (PF_DROP);
927 }
928 pf_nfrents++;
929 frent->fr_ip = h;
930 frent->fr_m = m;
931
932 /* Might return a completely reassembled mbuf, or NULL */
933 DPFPRINTF(("reass frag %d @ %d-%d\n", h->ip_id, fragoff, max));
934 *m0 = m = pf_reassemble(m0, &frag, frent, mff);
935
936 if (m == NULL)
937 return (PF_DROP);
938
939 if (frag != NULL && (frag->fr_flags & PFFRAG_DROP))
940 goto drop;
941
942 h = mtod(m, struct ip *);
943 } else {
944 /* non-buffering fragment cache (drops or masks overlaps) */
945 int nomem = 0;
946
947 if (dir == PF_OUT && m->m_pkthdr.pf.flags & PF_TAG_FRAGCACHE) {
948 /*
949 * Already passed the fragment cache in the
950 * input direction. If we continued, it would
951 * appear to be a dup and would be dropped.
952 */
953 goto fragment_pass;
954 }
955
956 frag = pf_find_fragment(h, &pf_cache_tree[cpu]);
957
958 /* Check if we saw the last fragment already */
959 if (frag != NULL && (frag->fr_flags & PFFRAG_SEENLAST) &&
960 max > frag->fr_max) {
961 if (r->rule_flag & PFRULE_FRAGDROP)
962 frag->fr_flags |= PFFRAG_DROP;
963 goto bad;
964 }
965
966 *m0 = m = pf_fragcache(m0, h, &frag, mff,
967 (r->rule_flag & PFRULE_FRAGDROP) ? 1 : 0, &nomem);
968 if (m == NULL) {
969 if (nomem)
970 goto no_mem;
971 goto drop;
972 }
973
974 if (dir == PF_IN)
975 m->m_pkthdr.pf.flags |= PF_TAG_FRAGCACHE;
976
977 if (frag != NULL && (frag->fr_flags & PFFRAG_DROP))
978 goto drop;
979 goto fragment_pass;
980 }
981
982 no_fragment:
983 /* At this point, only IP_DF is allowed in ip_off */
984 if (h->ip_off & ~IP_DF) {
985 u_int16_t ip_off = h->ip_off;
986
987 h->ip_off &= IP_DF;
988 h->ip_sum = pf_cksum_fixup(h->ip_sum, htons(ip_off), htons(h->ip_off), 0);
989 }
990
991 /* Enforce a minimum ttl, may cause endless packet loops */
992 if (r->min_ttl && h->ip_ttl < r->min_ttl) {
993 u_int16_t ip_ttl = h->ip_ttl;
994
995 h->ip_ttl = r->min_ttl;
996 h->ip_sum = pf_cksum_fixup(h->ip_sum, ip_ttl, h->ip_ttl, 0);
997 }
998
999 /* Enforce tos */
1000 if (r->rule_flag & PFRULE_SET_TOS) {
1001 u_int16_t ov, nv;
1002
1003 ov = *(u_int16_t *)h;
1004 h->ip_tos = r->set_tos;
1005 nv = *(u_int16_t *)h;
1006
1007 h->ip_sum = pf_cksum_fixup(h->ip_sum, ov, nv, 0);
1008 }
1009
1010 if (r->rule_flag & PFRULE_RANDOMID) {
1011 u_int16_t ip_id = h->ip_id;
1012
1013 h->ip_id = ip_randomid();
1014 h->ip_sum = pf_cksum_fixup(h->ip_sum, ip_id, h->ip_id, 0);
1015 }
1016 if ((r->rule_flag & (PFRULE_FRAGCROP|PFRULE_FRAGDROP)) == 0)
1017 pd->flags |= PFDESC_IP_REAS;
1018
1019 return (PF_PASS);
1020
1021 fragment_pass:
1022 /* Enforce a minimum ttl, may cause endless packet loops */
1023 if (r->min_ttl && h->ip_ttl < r->min_ttl) {
1024 u_int16_t ip_ttl = h->ip_ttl;
1025
1026 h->ip_ttl = r->min_ttl;
1027 h->ip_sum = pf_cksum_fixup(h->ip_sum, ip_ttl, h->ip_ttl, 0);
1028 }
1029 /* Enforce tos */
1030 if (r->rule_flag & PFRULE_SET_TOS) {
1031 u_int16_t ov, nv;
1032
1033 ov = *(u_int16_t *)h;
1034 h->ip_tos = r->set_tos;
1035 nv = *(u_int16_t *)h;
1036
1037 h->ip_sum = pf_cksum_fixup(h->ip_sum, ov, nv, 0);
1038 }
1039 if ((r->rule_flag & (PFRULE_FRAGCROP|PFRULE_FRAGDROP)) == 0)
1040 pd->flags |= PFDESC_IP_REAS;
1041 return (PF_PASS);
1042
1043 no_mem:
1044 REASON_SET(reason, PFRES_MEMORY);
1045 if (r != NULL && r->log)
1046 PFLOG_PACKET(kif, h, m, AF_INET, dir, *reason, r, NULL, NULL, pd);
1047 return (PF_DROP);
1048
1049 drop:
1050 REASON_SET(reason, PFRES_NORM);
1051 if (r != NULL && r->log)
1052 PFLOG_PACKET(kif, h, m, AF_INET, dir, *reason, r, NULL, NULL, pd);
1053 return (PF_DROP);
1054
1055 bad:
1056 DPFPRINTF(("dropping bad fragment\n"));
1057
1058 /* Free associated fragments */
1059 if (frag != NULL)
1060 pf_free_fragment(frag);
1061
1062 REASON_SET(reason, PFRES_FRAG);
1063 if (r != NULL && r->log)
1064 PFLOG_PACKET(kif, h, m, AF_INET, dir, *reason, r, NULL, NULL, pd);
1065
1066 return (PF_DROP);
1067 }
1068
1069 #ifdef INET6
1070 int
1071 pf_normalize_ip6(struct mbuf **m0, int dir, struct pfi_kif *kif,
1072 u_short *reason, struct pf_pdesc *pd)
1073 {
1074 struct mbuf *m = *m0;
1075 struct pf_rule *r;
1076 struct ip6_hdr *h = mtod(m, struct ip6_hdr *);
1077 int off;
1078 struct ip6_ext ext;
1079 struct ip6_opt opt;
1080 struct ip6_opt_jumbo jumbo;
1081 struct ip6_frag frag;
1082 u_int32_t jumbolen = 0, plen;
1083 u_int16_t fragoff = 0;
1084 int optend;
1085 int ooff;
1086 u_int8_t proto;
1087 int terminal;
1088
1089 r = TAILQ_FIRST(pf_main_ruleset.rules[PF_RULESET_SCRUB].active.ptr);
1090 while (r != NULL) {
1091 r->evaluations++;
1092 if (pfi_kif_match(r->kif, kif) == r->ifnot)
1093 r = r->skip[PF_SKIP_IFP].ptr;
1094 else if (r->direction && r->direction != dir)
1095 r = r->skip[PF_SKIP_DIR].ptr;
1096 else if (r->af && r->af != AF_INET6)
1097 r = r->skip[PF_SKIP_AF].ptr;
1098 #if 0 /* header chain! */
1099 else if (r->proto && r->proto != h->ip6_nxt)
1100 r = r->skip[PF_SKIP_PROTO].ptr;
1101 #endif
1102 else if (PF_MISMATCHAW(&r->src.addr,
1103 (struct pf_addr *)&h->ip6_src, AF_INET6,
1104 r->src.neg, kif))
1105 r = r->skip[PF_SKIP_SRC_ADDR].ptr;
1106 else if (PF_MISMATCHAW(&r->dst.addr,
1107 (struct pf_addr *)&h->ip6_dst, AF_INET6,
1108 r->dst.neg, NULL))
1109 r = r->skip[PF_SKIP_DST_ADDR].ptr;
1110 else
1111 break;
1112 }
1113
1114 if (r == NULL || r->action == PF_NOSCRUB)
1115 return (PF_PASS);
1116 else {
1117 r->packets[dir == PF_OUT]++;
1118 r->bytes[dir == PF_OUT] += pd->tot_len;
1119 }
1120
1121 /* Check for illegal packets */
1122 if (sizeof(struct ip6_hdr) + IPV6_MAXPACKET < m->m_pkthdr.len)
1123 goto drop;
1124
1125 off = sizeof(struct ip6_hdr);
1126 proto = h->ip6_nxt;
1127 terminal = 0;
1128 do {
1129 switch (proto) {
1130 case IPPROTO_FRAGMENT:
1131 goto fragment;
1132 break;
1133 case IPPROTO_AH:
1134 case IPPROTO_ROUTING:
1135 case IPPROTO_DSTOPTS:
1136 if (!pf_pull_hdr(m, off, &ext, sizeof(ext), NULL,
1137 NULL, AF_INET6))
1138 goto shortpkt;
1139 if (proto == IPPROTO_AH)
1140 off += (ext.ip6e_len + 2) * 4;
1141 else
1142 off += (ext.ip6e_len + 1) * 8;
1143 proto = ext.ip6e_nxt;
1144 break;
1145 case IPPROTO_HOPOPTS:
1146 if (!pf_pull_hdr(m, off, &ext, sizeof(ext), NULL,
1147 NULL, AF_INET6))
1148 goto shortpkt;
1149 optend = off + (ext.ip6e_len + 1) * 8;
1150 ooff = off + sizeof(ext);
1151 do {
1152 if (!pf_pull_hdr(m, ooff, &opt.ip6o_type,
1153 sizeof(opt.ip6o_type), NULL, NULL,
1154 AF_INET6))
1155 goto shortpkt;
1156 if (opt.ip6o_type == IP6OPT_PAD1) {
1157 ooff++;
1158 continue;
1159 }
1160 if (!pf_pull_hdr(m, ooff, &opt, sizeof(opt),
1161 NULL, NULL, AF_INET6))
1162 goto shortpkt;
1163 if (ooff + sizeof(opt) + opt.ip6o_len > optend)
1164 goto drop;
1165 switch (opt.ip6o_type) {
1166 case IP6OPT_JUMBO:
1167 if (h->ip6_plen != 0)
1168 goto drop;
1169 if (!pf_pull_hdr(m, ooff, &jumbo,
1170 sizeof(jumbo), NULL, NULL,
1171 AF_INET6))
1172 goto shortpkt;
1173 memcpy(&jumbolen, jumbo.ip6oj_jumbo_len,
1174 sizeof(jumbolen));
1175 jumbolen = ntohl(jumbolen);
1176 if (jumbolen <= IPV6_MAXPACKET)
1177 goto drop;
1178 if (sizeof(struct ip6_hdr) + jumbolen !=
1179 m->m_pkthdr.len)
1180 goto drop;
1181 break;
1182 default:
1183 break;
1184 }
1185 ooff += sizeof(opt) + opt.ip6o_len;
1186 } while (ooff < optend);
1187
1188 off = optend;
1189 proto = ext.ip6e_nxt;
1190 break;
1191 default:
1192 terminal = 1;
1193 break;
1194 }
1195 } while (!terminal);
1196
1197 /* jumbo payload option must be present, or plen > 0 */
1198 if (ntohs(h->ip6_plen) == 0)
1199 plen = jumbolen;
1200 else
1201 plen = ntohs(h->ip6_plen);
1202 if (plen == 0)
1203 goto drop;
1204 if (sizeof(struct ip6_hdr) + plen > m->m_pkthdr.len)
1205 goto shortpkt;
1206
1207 /* Enforce a minimum ttl, may cause endless packet loops */
1208 if (r->min_ttl && h->ip6_hlim < r->min_ttl)
1209 h->ip6_hlim = r->min_ttl;
1210
1211 return (PF_PASS);
1212
1213 fragment:
1214 if (ntohs(h->ip6_plen) == 0 || jumbolen)
1215 goto drop;
1216 plen = ntohs(h->ip6_plen);
1217
1218 if (!pf_pull_hdr(m, off, &frag, sizeof(frag), NULL, NULL, AF_INET6))
1219 goto shortpkt;
1220 fragoff = ntohs(frag.ip6f_offlg & IP6F_OFF_MASK);
1221 if (fragoff + (plen - off - sizeof(frag)) > IPV6_MAXPACKET)
1222 goto badfrag;
1223
1224 /* do something about it */
1225 /* remember to set pd->flags |= PFDESC_IP_REAS */
1226 return (PF_PASS);
1227
1228 shortpkt:
1229 REASON_SET(reason, PFRES_SHORT);
1230 if (r != NULL && r->log)
1231 PFLOG_PACKET(kif, h, m, AF_INET6, dir, *reason, r, NULL, NULL, pd);
1232 return (PF_DROP);
1233
1234 drop:
1235 REASON_SET(reason, PFRES_NORM);
1236 if (r != NULL && r->log)
1237 PFLOG_PACKET(kif, h, m, AF_INET6, dir, *reason, r, NULL, NULL, pd);
1238 return (PF_DROP);
1239
1240 badfrag:
1241 REASON_SET(reason, PFRES_FRAG);
1242 if (r != NULL && r->log)
1243 PFLOG_PACKET(kif, h, m, AF_INET6, dir, *reason, r, NULL, NULL, pd);
1244 return (PF_DROP);
1245 }
1246 #endif /* INET6 */
1247
1248 int
1249 pf_normalize_tcp(int dir, struct pfi_kif *kif, struct mbuf *m, int ipoff,
1250 int off, void *h, struct pf_pdesc *pd)
1251 {
1252 struct pf_rule *r, *rm = NULL;
1253 struct tcphdr *th = pd->hdr.tcp;
1254 int rewrite = 0;
1255 u_short reason;
1256 u_int8_t flags;
1257 sa_family_t af = pd->af;
1258
1259 r = TAILQ_FIRST(pf_main_ruleset.rules[PF_RULESET_SCRUB].active.ptr);
1260 while (r != NULL) {
1261 r->evaluations++;
1262 if (pfi_kif_match(r->kif, kif) == r->ifnot)
1263 r = r->skip[PF_SKIP_IFP].ptr;
1264 else if (r->direction && r->direction != dir)
1265 r = r->skip[PF_SKIP_DIR].ptr;
1266 else if (r->af && r->af != af)
1267 r = r->skip[PF_SKIP_AF].ptr;
1268 else if (r->proto && r->proto != pd->proto)
1269 r = r->skip[PF_SKIP_PROTO].ptr;
1270 else if (PF_MISMATCHAW(&r->src.addr, pd->src, af,
1271 r->src.neg, kif))
1272 r = r->skip[PF_SKIP_SRC_ADDR].ptr;
1273 else if (r->src.port_op && !pf_match_port(r->src.port_op,
1274 r->src.port[0], r->src.port[1], th->th_sport))
1275 r = r->skip[PF_SKIP_SRC_PORT].ptr;
1276 else if (PF_MISMATCHAW(&r->dst.addr, pd->dst, af,
1277 r->dst.neg, NULL))
1278 r = r->skip[PF_SKIP_DST_ADDR].ptr;
1279 else if (r->dst.port_op && !pf_match_port(r->dst.port_op,
1280 r->dst.port[0], r->dst.port[1], th->th_dport))
1281 r = r->skip[PF_SKIP_DST_PORT].ptr;
1282 else if (r->os_fingerprint != PF_OSFP_ANY && !pf_osfp_match(
1283 pf_osfp_fingerprint(pd, m, off, th),
1284 r->os_fingerprint))
1285 r = TAILQ_NEXT(r, entries);
1286 else {
1287 rm = r;
1288 break;
1289 }
1290 }
1291
1292 if (rm == NULL || rm->action == PF_NOSCRUB)
1293 return (PF_PASS);
1294 else {
1295 r->packets[dir == PF_OUT]++;
1296 r->bytes[dir == PF_OUT] += pd->tot_len;
1297 }
1298
1299 if (rm->rule_flag & PFRULE_REASSEMBLE_TCP)
1300 pd->flags |= PFDESC_TCP_NORM;
1301
1302 flags = th->th_flags;
1303 if (flags & TH_SYN) {
1304 /* Illegal packet */
1305 if (flags & TH_RST)
1306 goto tcp_drop;
1307
1308 if (flags & TH_FIN)
1309 flags &= ~TH_FIN;
1310 } else {
1311 /* Illegal packet */
1312 if (!(flags & (TH_ACK|TH_RST)))
1313 goto tcp_drop;
1314 }
1315
1316 if (!(flags & TH_ACK)) {
1317 /* These flags are only valid if ACK is set */
1318 if ((flags & TH_FIN) || (flags & TH_PUSH) || (flags & TH_URG))
1319 goto tcp_drop;
1320 }
1321
1322 /* Check for illegal header length */
1323 if (th->th_off < (sizeof(struct tcphdr) >> 2))
1324 goto tcp_drop;
1325
1326 /* If flags changed, or reserved data set, then adjust */
1327 if (flags != th->th_flags || th->th_x2 != 0) {
1328 u_int16_t ov, nv;
1329
1330 ov = *(u_int16_t *)(&th->th_ack + 1);
1331 th->th_flags = flags;
1332 th->th_x2 = 0;
1333 nv = *(u_int16_t *)(&th->th_ack + 1);
1334
1335 th->th_sum = pf_cksum_fixup(th->th_sum, ov, nv, 0);
1336 rewrite = 1;
1337 }
1338
1339 /* Remove urgent pointer, if TH_URG is not set */
1340 if (!(flags & TH_URG) && th->th_urp) {
1341 th->th_sum = pf_cksum_fixup(th->th_sum, th->th_urp, 0, 0);
1342 th->th_urp = 0;
1343 rewrite = 1;
1344 }
1345
1346 /* Process options */
1347 if (r->max_mss && pf_normalize_tcpopt(r, m, th, off, pd->af))
1348 rewrite = 1;
1349
1350 /* copy back packet headers if we sanitized */
1351 if (rewrite)
1352 m_copyback(m, off, sizeof(*th), (caddr_t)th);
1353
1354 return (PF_PASS);
1355
1356 tcp_drop:
1357 REASON_SET(&reason, PFRES_NORM);
1358 if (rm != NULL && r->log)
1359 PFLOG_PACKET(kif, h, m, AF_INET, dir, reason, r, NULL, NULL, pd);
1360 return (PF_DROP);
1361 }
1362
1363 int
1364 pf_normalize_tcp_init(struct mbuf *m, int off, struct pf_pdesc *pd,
1365 struct tcphdr *th, struct pf_state_peer *src, struct pf_state_peer *dst)
1366 {
1367 u_int32_t tsval, tsecr;
1368 u_int8_t hdr[60];
1369 u_int8_t *opt;
1370
1371 KASSERT((src->scrub == NULL),
1372 ("pf_normalize_tcp_init: src->scrub != NULL"));
1373
1374 src->scrub = kmalloc(sizeof(struct pf_state_scrub), M_PFSTATESCRUBPL,
1375 M_NOWAIT | M_ZERO);
1376 if (src->scrub == NULL)
1377 return (1);
1378
1379 switch (pd->af) {
1380 #ifdef INET
1381 case AF_INET: {
1382 struct ip *h = mtod(m, struct ip *);
1383 src->scrub->pfss_ttl = h->ip_ttl;
1384 break;
1385 }
1386 #endif /* INET */
1387 #ifdef INET6
1388 case AF_INET6: {
1389 struct ip6_hdr *h = mtod(m, struct ip6_hdr *);
1390 src->scrub->pfss_ttl = h->ip6_hlim;
1391 break;
1392 }
1393 #endif /* INET6 */
1394 }
1395
1396
1397 /*
1398 * All normalizations below are only begun if we see the start of
1399 * the connections. They must all set an enabled bit in pfss_flags
1400 */
1401 if ((th->th_flags & TH_SYN) == 0)
1402 return (0);
1403
1404
1405 if (th->th_off > (sizeof(struct tcphdr) >> 2) && src->scrub &&
1406 pf_pull_hdr(m, off, hdr, th->th_off << 2, NULL, NULL, pd->af)) {
1407 /* Diddle with TCP options */
1408 int hlen;
1409 opt = hdr + sizeof(struct tcphdr);
1410 hlen = (th->th_off << 2) - sizeof(struct tcphdr);
1411 while (hlen >= TCPOLEN_TIMESTAMP) {
1412 switch (*opt) {
1413 case TCPOPT_EOL: /* FALLTHROUGH */
1414 case TCPOPT_NOP:
1415 opt++;
1416 hlen--;
1417 break;
1418 case TCPOPT_TIMESTAMP:
1419 if (opt[1] >= TCPOLEN_TIMESTAMP) {
1420 src->scrub->pfss_flags |=
1421 PFSS_TIMESTAMP;
1422 src->scrub->pfss_ts_mod = karc4random();
1423
1424 /* note PFSS_PAWS not set yet */
1425 memcpy(&tsval, &opt[2],
1426 sizeof(u_int32_t));
1427 memcpy(&tsecr, &opt[6],
1428 sizeof(u_int32_t));
1429 src->scrub->pfss_tsval0 = ntohl(tsval);
1430 src->scrub->pfss_tsval = ntohl(tsval);
1431 src->scrub->pfss_tsecr = ntohl(tsecr);
1432 getmicrouptime(&src->scrub->pfss_last);
1433 }
1434 /* FALLTHROUGH */
1435 default:
1436 hlen -= MAX(opt[1], 2);
1437 opt += MAX(opt[1], 2);
1438 break;
1439 }
1440 }
1441 }
1442
1443 return (0);
1444 }
1445
1446 void
1447 pf_normalize_tcp_cleanup(struct pf_state *state)
1448 {
1449 if (state->src.scrub)
1450 kfree(state->src.scrub, M_PFSTATESCRUBPL);
1451 if (state->dst.scrub)
1452 kfree(state->dst.scrub, M_PFSTATESCRUBPL);
1453
1454 /* Someday... flush the TCP segment reassembly descriptors. */
1455 }
1456
1457 int
1458 pf_normalize_tcp_stateful(struct mbuf *m, int off, struct pf_pdesc *pd,
1459 u_short *reason, struct tcphdr *th, struct pf_state *state,
1460 struct pf_state_peer *src, struct pf_state_peer *dst, int *writeback)
1461 {
1462 struct timeval uptime;
1463 u_int32_t tsval, tsecr;
1464 u_int tsval_from_last;
1465 u_int8_t hdr[60];
1466 u_int8_t *opt;
1467 int copyback = 0;
1468 int got_ts = 0;
1469
1470 KASSERT((src->scrub || dst->scrub),
1471 ("pf_normalize_tcp_statefull: src->scrub && dst->scrub!"));
1472
1473 /*
1474 * Enforce the minimum TTL seen for this connection. Negate a common
1475 * technique to evade an intrusion detection system and confuse
1476 * firewall state code.
1477 */
1478 switch (pd->af) {
1479 #ifdef INET
1480 case AF_INET: {
1481 if (src->scrub) {
1482 struct ip *h = mtod(m, struct ip *);
1483 if (h->ip_ttl > src->scrub->pfss_ttl)
1484 src->scrub->pfss_ttl = h->ip_ttl;
1485 h->ip_ttl = src->scrub->pfss_ttl;
1486 }
1487 break;
1488 }
1489 #endif /* INET */
1490 #ifdef INET6
1491 case AF_INET6: {
1492 if (src->scrub) {
1493 struct ip6_hdr *h = mtod(m, struct ip6_hdr *);
1494 if (h->ip6_hlim > src->scrub->pfss_ttl)
1495 src->scrub->pfss_ttl = h->ip6_hlim;
1496 h->ip6_hlim = src->scrub->pfss_ttl;
1497 }
1498 break;
1499 }
1500 #endif /* INET6 */
1501 }
1502
1503 if (th->th_off > (sizeof(struct tcphdr) >> 2) &&
1504 ((src->scrub && (src->scrub->pfss_flags & PFSS_TIMESTAMP)) ||
1505 (dst->scrub && (dst->scrub->pfss_flags & PFSS_TIMESTAMP))) &&
1506 pf_pull_hdr(m, off, hdr, th->th_off << 2, NULL, NULL, pd->af)) {
1507 /* Diddle with TCP options */
1508 int hlen;
1509 opt = hdr + sizeof(struct tcphdr);
1510 hlen = (th->th_off << 2) - sizeof(struct tcphdr);
1511 while (hlen >= TCPOLEN_TIMESTAMP) {
1512 switch (*opt) {
1513 case TCPOPT_EOL: /* FALLTHROUGH */
1514 case TCPOPT_NOP:
1515 opt++;
1516 hlen--;
1517 break;
1518 case TCPOPT_TIMESTAMP:
1519 /* Modulate the timestamps. Can be used for
1520 * NAT detection, OS uptime determination or
1521 * reboot detection.
1522 */
1523
1524 if (got_ts) {
1525 /* Huh? Multiple timestamps!? */
1526 if (pf_status.debug >= PF_DEBUG_MISC) {
1527 DPFPRINTF(("multiple TS??"));
1528 pf_print_state(state);
1529 kprintf("\n");
1530 }
1531 REASON_SET(reason, PFRES_TS);
1532 return (PF_DROP);
1533 }
1534 if (opt[1] >= TCPOLEN_TIMESTAMP) {
1535 memcpy(&tsval, &opt[2],
1536 sizeof(u_int32_t));
1537 if (tsval && src->scrub &&
1538 (src->scrub->pfss_flags &
1539 PFSS_TIMESTAMP)) {
1540 tsval = ntohl(tsval);
1541 pf_change_a(&opt[2],
1542 &th->th_sum,
1543 htonl(tsval +
1544 src->scrub->pfss_ts_mod),
1545 0);
1546 copyback = 1;
1547 }
1548
1549 /* Modulate TS reply iff valid (!0) */
1550 memcpy(&tsecr, &opt[6],
1551 sizeof(u_int32_t));
1552 if (tsecr && dst->scrub &&
1553 (dst->scrub->pfss_flags &
1554 PFSS_TIMESTAMP)) {
1555 tsecr = ntohl(tsecr)
1556 - dst->scrub->pfss_ts_mod;
1557 pf_change_a(&opt[6],
1558 &th->th_sum, htonl(tsecr),
1559 0);
1560 copyback = 1;
1561 }
1562 got_ts = 1;
1563 }
1564 /* FALLTHROUGH */
1565 default:
1566 hlen -= MAX(opt[1], 2);
1567 opt += MAX(opt[1], 2);
1568 break;
1569 }
1570 }
1571 if (copyback) {
1572 /* Copyback the options, caller copys back header */
1573 *writeback = 1;
1574 m_copyback(m, off + sizeof(struct tcphdr),
1575 (th->th_off << 2) - sizeof(struct tcphdr), hdr +
1576 sizeof(struct tcphdr));
1577 }
1578 }
1579
1580
1581 /*
1582 * Must invalidate PAWS checks on connections idle for too long.
1583 * The fastest allowed timestamp clock is 1ms. That turns out to
1584 * be about 24 days before it wraps. XXX Right now our lowerbound
1585 * TS echo check only works for the first 12 days of a connection
1586 * when the TS has exhausted half its 32bit space
1587 */
1588 #define TS_MAX_IDLE (24*24*60*60)
1589 #define TS_MAX_CONN (12*24*60*60) /* XXX remove when better tsecr check */
1590
1591 getmicrouptime(&uptime);
1592 if (src->scrub && (src->scrub->pfss_flags & PFSS_PAWS) &&
1593 (uptime.tv_sec - src->scrub->pfss_last.tv_sec > TS_MAX_IDLE ||
1594 time_second - state->creation > TS_MAX_CONN)) {
1595 if (pf_status.debug >= PF_DEBUG_MISC) {
1596 DPFPRINTF(("src idled out of PAWS\n"));
1597 pf_print_state(state);
1598 kprintf("\n");
1599 }
1600 src->scrub->pfss_flags = (src->scrub->pfss_flags & ~PFSS_PAWS)
1601 | PFSS_PAWS_IDLED;
1602 }
1603 if (dst->scrub && (dst->scrub->pfss_flags & PFSS_PAWS) &&
1604 uptime.tv_sec - dst->scrub->pfss_last.tv_sec > TS_MAX_IDLE) {
1605 if (pf_status.debug >= PF_DEBUG_MISC) {
1606 DPFPRINTF(("dst idled out of PAWS\n"));
1607 pf_print_state(state);
1608 kprintf("\n");
1609 }
1610 dst->scrub->pfss_flags = (dst->scrub->pfss_flags & ~PFSS_PAWS)
1611 | PFSS_PAWS_IDLED;
1612 }
1613
1614 if (got_ts && src->scrub && dst->scrub &&
1615 (src->scrub->pfss_flags & PFSS_PAWS) &&
1616 (dst->scrub->pfss_flags & PFSS_PAWS)) {
1617 /* Validate that the timestamps are "in-window".
1618 * RFC1323 describes TCP Timestamp options that allow
1619 * measurement of RTT (round trip time) and PAWS
1620 * (protection against wrapped sequence numbers). PAWS
1621 * gives us a set of rules for rejecting packets on
1622 * long fat pipes (packets that were somehow delayed
1623 * in transit longer than the time it took to send the
1624 * full TCP sequence space of 4Gb). We can use these
1625 * rules and infer a few others that will let us treat
1626 * the 32bit timestamp and the 32bit echoed timestamp
1627 * as sequence numbers to prevent a blind attacker from
1628 * inserting packets into a connection.
1629 *
1630 * RFC1323 tells us:
1631 * - The timestamp on this packet must be greater than
1632 * or equal to the last value echoed by the other
1633 * endpoint. The RFC says those will be discarded
1634 * since it is a dup that has already been acked.
1635 * This gives us a lowerbound on the timestamp.
1636 * timestamp >= other last echoed timestamp
1637 * - The timestamp will be less than or equal to
1638 * the last timestamp plus the time between the
1639 * last packet and now. The RFC defines the max
1640 * clock rate as 1ms. We will allow clocks to be
1641 * up to 10% fast and will allow a total difference
1642 * or 30 seconds due to a route change. And this
1643 * gives us an upperbound on the timestamp.
1644 * timestamp <= last timestamp + max ticks
1645 * We have to be careful here. Windows will send an
1646 * initial timestamp of zero and then initialize it
1647 * to a random value after the 3whs; presumably to
1648 * avoid a DoS by having to call an expensive RNG
1649 * during a SYN flood. Proof MS has at least one
1650 * good security geek.
1651 *
1652 * - The TCP timestamp option must also echo the other
1653 * endpoints timestamp. The timestamp echoed is the
1654 * one carried on the earliest unacknowledged segment
1655 * on the left edge of the sequence window. The RFC
1656 * states that the host will reject any echoed
1657 * timestamps that were larger than any ever sent.
1658 * This gives us an upperbound on the TS echo.
1659 * tescr <= largest_tsval
1660 * - The lowerbound on the TS echo is a little more
1661 * tricky to determine. The other endpoint's echoed
1662 * values will not decrease. But there may be
1663 * network conditions that re-order packets and
1664 * cause our view of them to decrease. For now the
1665 * only lowerbound we can safely determine is that
1666 * the TS echo will never be less than the original
1667 * TS. XXX There is probably a better lowerbound.
1668 * Remove TS_MAX_CONN with better lowerbound check.
1669 * tescr >= other original TS
1670 *
1671 * It is also important to note that the fastest
1672 * timestamp clock of 1ms will wrap its 32bit space in
1673 * 24 days. So we just disable TS checking after 24
1674 * days of idle time. We actually must use a 12d
1675 * connection limit until we can come up with a better
1676 * lowerbound to the TS echo check.
1677 */
1678 struct timeval delta_ts;
1679 int ts_fudge;
1680
1681
1682 /*
1683 * PFTM_TS_DIFF is how many seconds of leeway to allow
1684 * a host's timestamp. This can happen if the previous
1685 * packet got delayed in transit for much longer than
1686 * this packet.
1687 */
1688 if ((ts_fudge = state->rule.ptr->timeout[PFTM_TS_DIFF]) == 0)
1689 ts_fudge = pf_default_rule.timeout[PFTM_TS_DIFF];
1690
1691
1692 /* Calculate max ticks since the last timestamp */
1693 #define TS_MAXFREQ 1100 /* RFC max TS freq of 1Khz + 10% skew */
1694 #define TS_MICROSECS 1000000 /* microseconds per second */
1695 #ifndef timersub
1696 #define timersub(tvp, uvp, vvp) \
1697 do { \
1698 (vvp)->tv_sec = (tvp)->tv_sec - (uvp)->tv_sec; \
1699 (vvp)->tv_usec = (tvp)->tv_usec - (uvp)->tv_usec; \
1700 if ((vvp)->tv_usec < 0) { \
1701 (vvp)->tv_sec--; \
1702 (vvp)->tv_usec += 1000000; \
1703 } \
1704 } while (0)
1705 #endif
1706
1707 timersub(&uptime, &src->scrub->pfss_last, &delta_ts);
1708 tsval_from_last = (delta_ts.tv_sec + ts_fudge) * TS_MAXFREQ;
1709 tsval_from_last += delta_ts.tv_usec / (TS_MICROSECS/TS_MAXFREQ);
1710
1711
1712 if ((src->state >= TCPS_ESTABLISHED &&
1713 dst->state >= TCPS_ESTABLISHED) &&
1714 (SEQ_LT(tsval, dst->scrub->pfss_tsecr) ||
1715 SEQ_GT(tsval, src->scrub->pfss_tsval + tsval_from_last) ||
1716 (tsecr && (SEQ_GT(tsecr, dst->scrub->pfss_tsval) ||
1717 SEQ_LT(tsecr, dst->scrub->pfss_tsval0))))) {
1718 /* Bad RFC1323 implementation or an insertion attack.
1719 *
1720 * - Solaris 2.6 and 2.7 are known to send another ACK
1721 * after the FIN,FIN|ACK,ACK closing that carries
1722 * an old timestamp.
1723 */
1724
1725 DPFPRINTF(("Timestamp failed %c%c%c%c\n",
1726 SEQ_LT(tsval, dst->scrub->pfss_tsecr) ? '0' : ' ',
1727 SEQ_GT(tsval, src->scrub->pfss_tsval +
1728 tsval_from_last) ? '1' : ' ',
1729 SEQ_GT(tsecr, dst->scrub->pfss_tsval) ? '2' : ' ',
1730 SEQ_LT(tsecr, dst->scrub->pfss_tsval0)? '3' : ' '));
1731 DPFPRINTF((" tsval: %u tsecr: %u +ticks: %u "
1732 "idle: %lus %lums\n",
1733 tsval, tsecr, tsval_from_last, delta_ts.tv_sec,
1734 delta_ts.tv_usec / 1000));
1735 DPFPRINTF((" src->tsval: %u tsecr: %u\n",
1736 src->scrub->pfss_tsval, src->scrub->pfss_tsecr));
1737 DPFPRINTF((" dst->tsval: %u tsecr: %u tsval0: %u"
1738 "\n", dst->scrub->pfss_tsval,
1739 dst->scrub->pfss_tsecr, dst->scrub->pfss_tsval0));
1740 if (pf_status.debug >= PF_DEBUG_MISC) {
1741 pf_print_state(state);
1742 pf_print_flags(th->th_flags);
1743 kprintf("\n");
1744 }
1745 REASON_SET(reason, PFRES_TS);
1746 return (PF_DROP);
1747 }
1748
1749 /* XXX I'd really like to require tsecr but it's optional */
1750
1751 } else if (!got_ts && (th->th_flags & TH_RST) == 0 &&
1752 ((src->state == TCPS_ESTABLISHED && dst->state == TCPS_ESTABLISHED)
1753 || pd->p_len > 0 || (th->th_flags & TH_SYN)) &&
1754 src->scrub && dst->scrub &&
1755 (src->scrub->pfss_flags & PFSS_PAWS) &&
1756 (dst->scrub->pfss_flags & PFSS_PAWS)) {
1757 /* Didn't send a timestamp. Timestamps aren't really useful
1758 * when:
1759 * - connection opening or closing (often not even sent).
1760 * but we must not let an attacker to put a FIN on a
1761 * data packet to sneak it through our ESTABLISHED check.
1762 * - on a TCP reset. RFC suggests not even looking at TS.
1763 * - on an empty ACK. The TS will not be echoed so it will
1764 * probably not help keep the RTT calculation in sync and
1765 * there isn't as much danger when the sequence numbers
1766 * got wrapped. So some stacks don't include TS on empty
1767 * ACKs :-(
1768 *
1769 * To minimize the disruption to mostly RFC1323 conformant
1770 * stacks, we will only require timestamps on data packets.
1771 *
1772 * And what do ya know, we cannot require timestamps on data
1773 * packets. There appear to be devices that do legitimate
1774 * TCP connection hijacking. There are HTTP devices that allow
1775 * a 3whs (with timestamps) and then buffer the HTTP request.
1776 * If the intermediate device has the HTTP response cache, it
1777 * will spoof the response but not bother timestamping its
1778 * packets. So we can look for the presence of a timestamp in
1779 * the first data packet and if there, require it in all future
1780 * packets.
1781 */
1782
1783 if (pd->p_len > 0 && (src->scrub->pfss_flags & PFSS_DATA_TS)) {
1784 /*
1785 * Hey! Someone tried to sneak a packet in. Or the
1786 * stack changed its RFC1323 behavior?!?!
1787 */
1788 if (pf_status.debug >= PF_DEBUG_MISC) {
1789 DPFPRINTF(("Did not receive expected RFC1323 "
1790 "timestamp\n"));
1791 pf_print_state(state);
1792 pf_print_flags(th->th_flags);
1793 kprintf("\n");
1794 }
1795 REASON_SET(reason, PFRES_TS);
1796 return (PF_DROP);
1797 }
1798 }
1799
1800
1801 /*
1802 * We will note if a host sends his data packets with or without
1803 * timestamps. And require all data packets to contain a timestamp
1804 * if the first does. PAWS implicitly requires that all data packets be
1805 * timestamped. But I think there are middle-man devices that hijack
1806 * TCP streams immediately after the 3whs and don't timestamp their
1807 * packets (seen in a WWW accelerator or cache).
1808 */
1809 if (pd->p_len > 0 && src->scrub && (src->scrub->pfss_flags &
1810 (PFSS_TIMESTAMP|PFSS_DATA_TS|PFSS_DATA_NOTS)) == PFSS_TIMESTAMP) {
1811 if (got_ts)
1812 src->scrub->pfss_flags |= PFSS_DATA_TS;
1813 else {
1814 src->scrub->pfss_flags |= PFSS_DATA_NOTS;
1815 if (pf_status.debug >= PF_DEBUG_MISC && dst->scrub &&
1816 (dst->scrub->pfss_flags & PFSS_TIMESTAMP)) {
1817 /* Don't warn if other host rejected RFC1323 */
1818 DPFPRINTF(("Broken RFC1323 stack did not "
1819 "timestamp data packet. Disabled PAWS "
1820 "security.\n"));
1821 pf_print_state(state);
1822 pf_print_flags(th->th_flags);
1823 kprintf("\n");
1824 }
1825 }
1826 }
1827
1828
1829 /*
1830 * Update PAWS values
1831 */
1832 if (got_ts && src->scrub && PFSS_TIMESTAMP == (src->scrub->pfss_flags &
1833 (PFSS_PAWS_IDLED|PFSS_TIMESTAMP))) {
1834 getmicrouptime(&src->scrub->pfss_last);
1835 if (SEQ_GEQ(tsval, src->scrub->pfss_tsval) ||
1836 (src->scrub->pfss_flags & PFSS_PAWS) == 0)
1837 src->scrub->pfss_tsval = tsval;
1838
1839 if (tsecr) {
1840 if (SEQ_GEQ(tsecr, src->scrub->pfss_tsecr) ||
1841 (src->scrub->pfss_flags & PFSS_PAWS) == 0)
1842 src->scrub->pfss_tsecr = tsecr;
1843
1844 if ((src->scrub->pfss_flags & PFSS_PAWS) == 0 &&
1845 (SEQ_LT(tsval, src->scrub->pfss_tsval0) ||
1846 src->scrub->pfss_tsval0 == 0)) {
1847 /* tsval0 MUST be the lowest timestamp */
1848 src->scrub->pfss_tsval0 = tsval;
1849 }
1850
1851 /* Only fully initialized after a TS gets echoed */
1852 if ((src->scrub->pfss_flags & PFSS_PAWS) == 0)
1853 src->scrub->pfss_flags |= PFSS_PAWS;
1854 }
1855 }
1856
1857 /* I have a dream.... TCP segment reassembly.... */
1858 return (0);
1859 }
1860
1861 int
1862 pf_normalize_tcpopt(struct pf_rule *r, struct mbuf *m, struct tcphdr *th,
1863 int off, sa_family_t af)
1864 {
1865 u_int16_t *mss;
1866 int thoff;
1867 int opt, cnt, optlen = 0;
1868 int rewrite = 0;
1869 u_char opts[TCP_MAXOLEN];
1870 u_char *optp = opts;
1871
1872 thoff = th->th_off << 2;
1873 cnt = thoff - sizeof(struct tcphdr);
1874
1875 if (cnt > 0 && !pf_pull_hdr(m, off + sizeof(*th), opts, cnt,
1876 NULL, NULL, af))
1877 return (rewrite);
1878
1879 for (; cnt > 0; cnt -= optlen, optp += optlen) {
1880 opt = optp[0];
1881 if (opt == TCPOPT_EOL)
1882 break;
1883 if (opt == TCPOPT_NOP)
1884 optlen = 1;
1885 else {
1886 if (cnt < 2)
1887 break;
1888 optlen = optp[1];
1889 if (optlen < 2 || optlen > cnt)
1890 break;
1891 }
1892 switch (opt) {
1893 case TCPOPT_MAXSEG:
1894 mss = (u_int16_t *)(optp + 2);
1895 if ((ntohs(*mss)) > r->max_mss) {
1896 th->th_sum = pf_cksum_fixup(th->th_sum,
1897 *mss, htons(r->max_mss), 0);
1898 *mss = htons(r->max_mss);
1899 rewrite = 1;
1900 }
1901 break;
1902 default:
1903 break;
1904 }
1905 }
1906
1907 if (rewrite)
1908 m_copyback(m, off + sizeof(*th), thoff - sizeof(*th), opts);
1909
1910 return (rewrite);
1911 }
DragonFly BSD