summaryrefslogtreecommitdiff
path: root/src/pluto/nat_traversal.c
blob: 5e9353b724d6c81206e58b4a5a8f00420fb66f0c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
/*
 * Copyright (C) 2010 Tobias Brunner
 * Copyright (C) 2009 Andreas Steffen
 * Hochschule fuer Technik Rapperswil
 * Copyright (C) 2002-2005 Mathieu Lafon
 * Arkoon Network Security
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 */

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <stdarg.h>
#include <syslog.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>     /* used only if MSG_NOSIGNAL not defined */
#include <sys/queue.h>

#include <library.h>
#include <crypto/hashers/hasher.h>

#include "constants.h"
#include "defs.h"
#include "log.h"
#include "server.h"
#include "state.h"
#include "connections.h"
#include "packet.h"
#include "demux.h"
#include "kernel.h"
#include "whack.h"
#include "timer.h"
#include "cookie.h"
#include "crypto.h"
#include "vendor.h"
#include "ike_alg.h"
#include "nat_traversal.h"

/* #define FORCE_NAT_TRAVERSAL */
#define NAT_D_DEBUG
#define NAT_T_SUPPORT_LAST_DRAFTS

#ifndef SOL_UDP
#define SOL_UDP 17
#endif

#ifndef UDP_ESPINUDP
#define UDP_ESPINUDP    100
#endif

#define DEFAULT_KEEP_ALIVE_PERIOD  20

#ifdef _IKE_ALG_H
/* Alg patch: hash_digest_len -> hash_digest_size */
#define hash_digest_len hash_digest_size
#endif

bool nat_traversal_enabled = FALSE;
bool nat_traversal_support_non_ike = FALSE;
bool nat_traversal_support_port_floating = FALSE;

static unsigned int _kap = 0;
static unsigned int _ka_evt = 0;
static bool _force_ka = 0;

static const char *natt_version = "0.6c";

void init_nat_traversal (bool activate, unsigned int keep_alive_period,
		bool fka, bool spf)
{
	nat_traversal_enabled = activate;
	nat_traversal_support_non_ike = activate;
#ifdef NAT_T_SUPPORT_LAST_DRAFTS
	nat_traversal_support_port_floating = activate ? spf : FALSE;
#endif
	_force_ka = fka;
	_kap = keep_alive_period ? keep_alive_period : DEFAULT_KEEP_ALIVE_PERIOD;
	plog("  including NAT-Traversal patch (Version %s)%s%s%s"
		 , natt_version, activate ? "" : " [disabled]"
		 , activate & fka ? " [Force KeepAlive]" : ""
		 , activate & !spf ? " [Port Floating disabled]" : "");
}

static void disable_nat_traversal (int type)
{
	if (type == ESPINUDP_WITH_NON_IKE)
		nat_traversal_support_non_ike = FALSE;
	else
		nat_traversal_support_port_floating = FALSE;

	if (!nat_traversal_support_non_ike &&
		!nat_traversal_support_port_floating)
			nat_traversal_enabled = FALSE;
}

static void _natd_hash(const struct hash_desc *oakley_hasher, char *hash,
		u_int8_t *icookie, u_int8_t *rcookie,
		const ip_address *ip, u_int16_t port)
{
	if (is_zero_cookie(icookie))
	{
		DBG_log("_natd_hash: Warning, icookie is zero !!");
	}
	if (is_zero_cookie(rcookie))
	{
		DBG_log("_natd_hash: Warning, rcookie is zero !!");
	}

	/**
	 * draft-ietf-ipsec-nat-t-ike-01.txt
	 *
	 *   HASH = HASH(CKY-I | CKY-R | IP | Port)
	 *
	 * All values in network order
	 */
	{
		chunk_t icookie_chunk = { icookie, COOKIE_SIZE };
		chunk_t rcookie_chunk = { rcookie, COOKIE_SIZE };
		chunk_t port_chunk = chunk_from_thing(port);
		chunk_t addr_chunk;
		hash_algorithm_t hash_alg;
		hasher_t *hasher;
		size_t hash_size;

		hash_alg = oakley_to_hash_algorithm(oakley_hasher->algo_id);
		hasher = lib->crypto->create_hasher(lib->crypto, hash_alg);
		hasher->get_hash(hasher, icookie_chunk, NULL);
		hasher->get_hash(hasher, rcookie_chunk, NULL);
		switch (addrtypeof(ip))
		{
			case AF_INET:
				addr_chunk = chunk_from_thing(ip->u.v4.sin_addr.s_addr);
				break;
			case AF_INET6:
				addr_chunk = chunk_from_thing(ip->u.v6.sin6_addr.s6_addr);
				break;
			default:
				addr_chunk = chunk_empty; /* should never occur */
		}
		hasher->get_hash(hasher, addr_chunk, NULL);
		hasher->get_hash(hasher, port_chunk, hash);
		hash_size = hasher->get_hash_size(hasher);
		hasher->destroy(hasher);
#ifdef NAT_D_DEBUG
		DBG(DBG_NATT,
			DBG_dump_chunk("_natd_hash: icookie=", icookie_chunk);
			DBG_dump_chunk("_natd_hash: rcookie=", rcookie_chunk);
			DBG_dump_chunk("_natd_hash: ip=", addr_chunk);
			DBG_log("_natd_hash: port=%d", port);
			DBG_dump("_natd_hash: hash=", hash, hash_size);
		)
#endif
	}
}

/* Add NAT-Traversal VIDs (supported ones)
 * used when we are Initiator
 */
bool nat_traversal_add_vid(u_int8_t np, pb_stream *outs)
{
	bool r = TRUE;

	if (nat_traversal_support_port_floating)
	{
		u_int8_t last_np = nat_traversal_support_non_ike ?
								ISAKMP_NEXT_VID : np;

		if (r)
			r = out_vendorid(ISAKMP_NEXT_VID, outs, VID_NATT_RFC);
		if (r)
			r = out_vendorid(ISAKMP_NEXT_VID, outs, VID_NATT_IETF_03);
		if (r)
			r = out_vendorid(ISAKMP_NEXT_VID, outs, VID_NATT_IETF_02);
		if (r)
			r = out_vendorid(last_np, outs, VID_NATT_IETF_02_N);
	}
	if (nat_traversal_support_non_ike)
	{
		if (r)
			r = out_vendorid(np, outs, VID_NATT_IETF_00);
	}
	return r;
}

u_int32_t nat_traversal_vid_to_method(unsigned short nat_t_vid)
{
	switch (nat_t_vid)
	{
	case VID_NATT_IETF_00:
		return LELEM(NAT_TRAVERSAL_IETF_00_01);
	case VID_NATT_IETF_02:
	case VID_NATT_IETF_02_N:
	case VID_NATT_IETF_03:
		return LELEM(NAT_TRAVERSAL_IETF_02_03);
	case VID_NATT_RFC:
		return LELEM(NAT_TRAVERSAL_RFC);
	}
	return 0;
}

void nat_traversal_natd_lookup(struct msg_digest *md)
{
	char hash[MAX_DIGEST_LEN];
	struct payload_digest *p;
	struct state *st = md->st;
	int i;

	if (!st || !md->iface || !st->st_oakley.hasher)
	{
		loglog(RC_LOG_SERIOUS, "NAT-Traversal: assert failed %s:%d"
				, __FILE__, __LINE__);
		return;
	}

	/** Count NAT-D **/
	for (p = md->chain[ISAKMP_NEXT_NATD_RFC], i=0; p != NULL; p = p->next, i++);

	/*
	 * We need at least 2 NAT-D (1 for us, many for peer)
	 */
	if (i < 2)
	{
		loglog(RC_LOG_SERIOUS,
			"NAT-Traversal: Only %d NAT-D - Aborting NAT-Traversal negociation", i);
		st->nat_traversal = 0;
		return;
	}

	/*
	 * First one with my IP & port
	 */
	p = md->chain[ISAKMP_NEXT_NATD_RFC];
	_natd_hash(st->st_oakley.hasher, hash, st->st_icookie, st->st_rcookie,
		&(md->iface->addr), ntohs(st->st_connection->spd.this.host_port));

	if (!(pbs_left(&p->pbs) == st->st_oakley.hasher->hash_digest_len &&
		  memeq(p->pbs.cur, hash, st->st_oakley.hasher->hash_digest_len)))
	{
#ifdef NAT_D_DEBUG
		DBG(DBG_NATT,
			DBG_log("NAT_TRAVERSAL_NAT_BHND_ME");
			DBG_dump("expected NAT-D:", hash
						, st->st_oakley.hasher->hash_digest_len);
			DBG_dump("received NAT-D:", p->pbs.cur, pbs_left(&p->pbs));
		)
#endif
		st->nat_traversal |= LELEM(NAT_TRAVERSAL_NAT_BHND_ME);
	}

	/*
	 * The others with sender IP & port
	 */
	_natd_hash(st->st_oakley.hasher, hash, st->st_icookie, st->st_rcookie,
				&(md->sender), ntohs(md->sender_port));
	for (p = p->next, i=0 ; p != NULL; p = p->next)
	{
		if (pbs_left(&p->pbs) == st->st_oakley.hasher->hash_digest_len &&
			memeq(p->pbs.cur, hash, st->st_oakley.hasher->hash_digest_len))
		{
			i++;
		}
	}
	if (!i)
	{
#ifdef NAT_D_DEBUG
		DBG(DBG_NATT,
			DBG_log("NAT_TRAVERSAL_NAT_BHND_PEER");
			DBG_dump("expected NAT-D:", hash
						, st->st_oakley.hasher->hash_digest_len);
			p = md->chain[ISAKMP_NEXT_NATD_RFC];
			for (p = p->next, i=0 ; p != NULL; p = p->next)
			{
				DBG_dump("received NAT-D:", p->pbs.cur, pbs_left(&p->pbs));
			}
		)
#endif
		st->nat_traversal |= LELEM(NAT_TRAVERSAL_NAT_BHND_PEER);
	}
#ifdef FORCE_NAT_TRAVERSAL
	st->nat_traversal |= LELEM(NAT_TRAVERSAL_NAT_BHND_PEER);
	st->nat_traversal |= LELEM(NAT_TRAVERSAL_NAT_BHND_ME);
#endif
}

bool nat_traversal_add_natd(u_int8_t np, pb_stream *outs,
		struct msg_digest *md)
{
	char hash[MAX_DIGEST_LEN];
	struct state *st = md->st;

	if (!st || !st->st_oakley.hasher)
	{
		loglog(RC_LOG_SERIOUS, "NAT-Traversal: assert failed %s:%d"
						, __FILE__, __LINE__);
		return FALSE;
	}

	DBG(DBG_EMITTING,
		DBG_log("sending NATD payloads")
	)

	/*
	 * First one with sender IP & port
	 */
	_natd_hash(st->st_oakley.hasher, hash, st->st_icookie,
		is_zero_cookie(st->st_rcookie) ? md->hdr.isa_rcookie : st->st_rcookie,
		&(md->sender),
#ifdef FORCE_NAT_TRAVERSAL
		0
#else
		ntohs(md->sender_port)
#endif
	);
	if (!out_generic_raw((st->nat_traversal & NAT_T_WITH_RFC_VALUES
		? ISAKMP_NEXT_NATD_RFC : ISAKMP_NEXT_NATD_DRAFTS), &isakmp_nat_d, outs,
		hash, st->st_oakley.hasher->hash_digest_len, "NAT-D"))
	{
		return FALSE;
	}

	/*
	 * Second one with my IP & port
	 */
	_natd_hash(st->st_oakley.hasher, hash, st->st_icookie,
		is_zero_cookie(st->st_rcookie) ? md->hdr.isa_rcookie : st->st_rcookie,
		&(md->iface->addr),
#ifdef FORCE_NAT_TRAVERSAL
		0
#else
		ntohs(st->st_connection->spd.this.host_port)
#endif
	);
	return (out_generic_raw(np, &isakmp_nat_d, outs,
		hash, st->st_oakley.hasher->hash_digest_len, "NAT-D"));
}

/*
 * nat_traversal_natoa_lookup()
 *
 * Look for NAT-OA in message
 */
void nat_traversal_natoa_lookup(struct msg_digest *md)
{
	struct payload_digest *p;
	struct state *st = md->st;
	int i;
	ip_address ip;

	if (!st || !md->iface)
	{
		loglog(RC_LOG_SERIOUS, "NAT-Traversal: assert failed %s:%d"
				, __FILE__, __LINE__);
		return;
	}

	/* Initialize NAT-OA */
	anyaddr(AF_INET, &st->nat_oa);

	/* Count NAT-OA **/
	for (p = md->chain[ISAKMP_NEXT_NATOA_RFC], i=0; p != NULL; p = p->next, i++);

	DBG(DBG_NATT,
		DBG_log("NAT-Traversal: received %d NAT-OA.", i)
	)

	if (i == 0)
		return;

	if (!(st->nat_traversal & LELEM(NAT_TRAVERSAL_NAT_BHND_PEER)))
	{
		loglog(RC_LOG_SERIOUS, "NAT-Traversal: received %d NAT-OA. "
						"ignored because peer is not NATed", i);
		return;
	}

	if (i > 1)
	{
		loglog(RC_LOG_SERIOUS, "NAT-Traversal: received %d NAT-OA. "
				"using first, ignoring others", i);
	}

	/* Take first */
	p = md->chain[ISAKMP_NEXT_NATOA_RFC];

	DBG(DBG_PARSING,
		DBG_dump("NAT-OA:", p->pbs.start, pbs_room(&p->pbs));
	);

	switch (p->payload.nat_oa.isanoa_idtype)
	{
	case ID_IPV4_ADDR:
		if (pbs_left(&p->pbs) == sizeof(struct in_addr))
		{
			initaddr(p->pbs.cur, pbs_left(&p->pbs), AF_INET, &ip);
		}
		else
		{
			loglog(RC_LOG_SERIOUS, "NAT-Traversal: received IPv4 NAT-OA "
						"with invalid IP size (%d)", (int)pbs_left(&p->pbs));
			return;
		}
		break;
	case ID_IPV6_ADDR:
		if (pbs_left(&p->pbs) == sizeof(struct in6_addr))
		{
			initaddr(p->pbs.cur, pbs_left(&p->pbs), AF_INET6, &ip);
		}
		else
		{
			loglog(RC_LOG_SERIOUS, "NAT-Traversal: received IPv6 NAT-OA "
						"with invalid IP size (%d)", (int)pbs_left(&p->pbs));
			return;
		}
		break;
	default:
		loglog(RC_LOG_SERIOUS, "NAT-Traversal: "
						"invalid ID Type (%d) in NAT-OA - ignored",
						p->payload.nat_oa.isanoa_idtype);
			return;
	}

	DBG(DBG_NATT,
		{
			char ip_t[ADDRTOT_BUF];
			addrtot(&ip, 0, ip_t, sizeof(ip_t));

			DBG_log("received NAT-OA: %s", ip_t);
		}
	)

	if (isanyaddr(&ip))
		loglog(RC_LOG_SERIOUS, "NAT-Traversal: received %%any NAT-OA...");
	else
		st->nat_oa = ip;
}

bool nat_traversal_add_natoa(u_int8_t np, pb_stream *outs,
		struct state *st)
{
	struct isakmp_nat_oa natoa;
	pb_stream pbs;
	unsigned char ip_val[sizeof(struct in6_addr)];
	size_t ip_len = 0;
	ip_address *ip;

	if ((!st) || (!st->st_connection))
	{
		loglog(RC_LOG_SERIOUS, "NAT-Traversal: assert failed %s:%d"
						, __FILE__, __LINE__);
		return FALSE;
	}
	ip = &(st->st_connection->spd.this.host_addr);

	memset(&natoa, 0, sizeof(natoa));
	natoa.isanoa_np = np;

	switch (addrtypeof(ip))
	{
	case AF_INET:
		ip_len = sizeof(ip->u.v4.sin_addr.s_addr);
		memcpy(ip_val, &ip->u.v4.sin_addr.s_addr, ip_len);
		natoa.isanoa_idtype = ID_IPV4_ADDR;
		break;
	case AF_INET6:
		ip_len = sizeof(ip->u.v6.sin6_addr.s6_addr);
		memcpy(ip_val, &ip->u.v6.sin6_addr.s6_addr, ip_len);
		natoa.isanoa_idtype = ID_IPV6_ADDR;
		break;
	default:
		loglog(RC_LOG_SERIOUS, "NAT-Traversal: "
						"invalid addrtypeof()=%d", addrtypeof(ip));
		return FALSE;
	}

	if (!out_struct(&natoa, &isakmp_nat_oa, outs, &pbs))
		return FALSE;

	if (!out_raw(ip_val, ip_len, &pbs, "NAT-OA"))
		return FALSE;

	DBG(DBG_NATT,
		DBG_dump("NAT-OA (S):", ip_val, ip_len)
	)

	close_output_pbs(&pbs);
	return TRUE;
}

void nat_traversal_show_result (u_int32_t nt, u_int16_t sport)
{
	const char *mth = NULL, *rslt = NULL;

	switch (nt & NAT_TRAVERSAL_METHOD)
	{
	case LELEM(NAT_TRAVERSAL_IETF_00_01):
		mth = natt_type_bitnames[0];
		break;
	case LELEM(NAT_TRAVERSAL_IETF_02_03):
		mth = natt_type_bitnames[1];
		break;
	case LELEM(NAT_TRAVERSAL_RFC):
		mth = natt_type_bitnames[2];
		break;
	}

	switch (nt & NAT_T_DETECTED)
	{
	case 0:
		rslt = "no NAT detected";
		break;
	case LELEM(NAT_TRAVERSAL_NAT_BHND_ME):
		rslt = "i am NATed";
		break;
	case LELEM(NAT_TRAVERSAL_NAT_BHND_PEER):
		rslt = "peer is NATed";
		break;
	case LELEM(NAT_TRAVERSAL_NAT_BHND_ME) | LELEM(NAT_TRAVERSAL_NAT_BHND_PEER):
		rslt = "both are NATed";
		break;
	}

	loglog(RC_LOG_SERIOUS,
		"NAT-Traversal: Result using %s: %s",
		mth ? mth : "unknown method",
		rslt ? rslt : "unknown result"
	);

	if ((nt & LELEM(NAT_TRAVERSAL_NAT_BHND_PEER))
	&&  (sport == IKE_UDP_PORT)
	&&  ((nt & NAT_T_WITH_PORT_FLOATING)==0))
	{
		loglog(RC_LOG_SERIOUS,
				"Warning: peer is NATed but source port is still udp/%d. "
				"Ipsec-passthrough NAT device suspected -- NAT-T may not work.",
				IKE_UDP_PORT
		);
	}
}

int nat_traversal_espinudp_socket (int sk, u_int32_t type)
{
	int r = setsockopt(sk, SOL_UDP, UDP_ESPINUDP, &type, sizeof(type));

	if (r < 0 && errno == ENOPROTOOPT)
	{
		loglog(RC_LOG_SERIOUS,
				"NAT-Traversal: ESPINUDP(%d) not supported by kernel -- "
				"NAT-T disabled", type);
		disable_nat_traversal(type);
	}
	return r;
}

void nat_traversal_new_ka_event (void)
{
	if (_ka_evt)
		return;  /* event already scheduled */

	event_schedule(EVENT_NAT_T_KEEPALIVE, _kap, NULL);
	_ka_evt = 1;
}

static void nat_traversal_send_ka (struct state *st)
{
	static unsigned char ka_payload = 0xff;
	chunk_t sav;

	DBG(DBG_NATT,
		DBG_log("ka_event: send NAT-KA to %s:%d",
				ip_str(&st->st_connection->spd.that.host_addr),
				st->st_connection->spd.that.host_port);
	)

	/* save state chunk */
	sav = st->st_tpacket;

	/* send keep alive */
	st->st_tpacket = chunk_create(&ka_payload, 1);
	send_packet(st, "NAT-T Keep Alive");

	/* restore state chunk */
	st->st_tpacket = sav;
}

/**
 * Find ISAKMP States with NAT-T and send keep-alive
 */
static void nat_traversal_ka_event_state (struct state *st, void *data)
{
	unsigned int *_kap_st = (unsigned int *)data;
	const connection_t *c = st->st_connection;

	if (!c)
		return;

	if ((st->st_state == STATE_MAIN_R3 || st->st_state == STATE_MAIN_I4)
	&&  (st->nat_traversal & NAT_T_DETECTED)
	&&  ((st->nat_traversal & LELEM(NAT_TRAVERSAL_NAT_BHND_ME)) || _force_ka))
	{
		/*
		 * - ISAKMP established
		 * - NAT-Traversal detected
		 * - NAT-KeepAlive needed (we are NATed)
		 */
		if (c->newest_isakmp_sa != st->st_serialno)
		{
			/*
			 * if newest is also valid, ignore this one, we will only use
			 * newest.
			 */
			struct state *st_newest;

			st_newest = state_with_serialno(c->newest_isakmp_sa);
			if (st_newest
			&& (st_newest->st_state == STATE_MAIN_R3 || st_newest->st_state == STATE_MAIN_I4)
			&& (st_newest->nat_traversal & NAT_T_DETECTED)
			&& ((st_newest->nat_traversal & LELEM(NAT_TRAVERSAL_NAT_BHND_ME)) || _force_ka))
			{
				return;
			}
		}
		set_cur_state(st);
		nat_traversal_send_ka(st);
		reset_cur_state();
		(*_kap_st)++;
	}
}

void nat_traversal_ka_event (void)
{
	unsigned int _kap_st = 0;

	_ka_evt = 0;  /* ready to be reschedule */

	for_each_state((void *)nat_traversal_ka_event_state, &_kap_st);

	/* if there are still states who needs Keep-Alive, schedule new event */
	if (_kap_st)
		nat_traversal_new_ka_event();
}

struct _new_mapp_nfo {
		ip_address addr;
		u_int16_t sport, dport;
};

static void nat_traversal_find_new_mapp_state (struct state *st, void *data)
{
	connection_t *c = st->st_connection;
	struct _new_mapp_nfo *nfo = (struct _new_mapp_nfo *)data;

	if (c != NULL
	&& sameaddr(&c->spd.that.host_addr, &(nfo->addr))
	&&  c->spd.that.host_port == nfo->sport)
	{

		/* change host port */
		c->spd.that.host_port = nfo->dport;

		if (IS_IPSEC_SA_ESTABLISHED(st->st_state)
		||  IS_ONLY_INBOUND_IPSEC_SA_ESTABLISHED(st->st_state))
		{
			if (!update_ipsec_sa(st))
			{
				/*
				 * If ipsec update failed, restore old port or we'll
				 * not be able to update anymore.
				 */
				c->spd.that.host_port = nfo->sport;
			}
		}
	}
}

static int nat_traversal_new_mapping(const ip_address *src, u_int16_t sport,
		const ip_address *dst, u_int16_t dport)
{
	char srca[ADDRTOT_BUF], dsta[ADDRTOT_BUF];
	struct _new_mapp_nfo nfo;

	addrtot(src, 0, srca, ADDRTOT_BUF);
	addrtot(dst, 0, dsta, ADDRTOT_BUF);

	if (!sameaddr(src, dst))
	{
		loglog(RC_LOG_SERIOUS, "nat_traversal_new_mapping: "
				"address change currently not supported [%s:%d,%s:%d]",
				srca, sport, dsta, dport);
		return -1;
	}

	if (sport == dport)
	{
		/* no change */
		return 0;
	}

	DBG_log("NAT-T: new mapping %s:%d/%d)", srca, sport, dport);

	nfo.addr = *src;
	nfo.sport = sport;
	nfo.dport = dport;

	for_each_state((void *)nat_traversal_find_new_mapp_state, &nfo);

	return 0;
}

void nat_traversal_change_port_lookup(struct msg_digest *md, struct state *st)
{
	connection_t *c = st ? st->st_connection : NULL;
	struct iface *i = NULL;

	if ((st == NULL) || (c == NULL))
		return;

	if (md)
	{
		/*
		 * If source port has changed, update (including other states and
		 * established kernel SA)
		 */
		if (c->spd.that.host_port != md->sender_port)
		{
			nat_traversal_new_mapping(&c->spd.that.host_addr, c->spd.that.host_port,
						&c->spd.that.host_addr, md->sender_port);
		}

		/*
		 * If interface type has changed, update local port (500/4500)
		 */
		if ((c->spd.this.host_port == NAT_T_IKE_FLOAT_PORT && !md->iface->ike_float)
		||  (c->spd.this.host_port != NAT_T_IKE_FLOAT_PORT &&  md->iface->ike_float))
		{
			c->spd.this.host_port = (md->iface->ike_float)
				? NAT_T_IKE_FLOAT_PORT : pluto_port;

			DBG(DBG_NATT,
				DBG_log("NAT-T: updating local port to %d", c->spd.this.host_port);
			);
		}
	}

	/*
	 * If we're initiator and NAT-T (with port floating) is detected, we
	 * need to change port (MAIN_I3 or QUICK_I1)
	 */
	if ((st->st_state == STATE_MAIN_I3 || st->st_state == STATE_QUICK_I1)
	&&  (st->nat_traversal & NAT_T_WITH_PORT_FLOATING)
	&&  (st->nat_traversal & NAT_T_DETECTED)
	&&  (c->spd.this.host_port != NAT_T_IKE_FLOAT_PORT))
	{
		DBG(DBG_NATT,
			DBG_log("NAT-T: floating to port %d", NAT_T_IKE_FLOAT_PORT);
		)
		c->spd.this.host_port = NAT_T_IKE_FLOAT_PORT;
		c->spd.that.host_port = NAT_T_IKE_FLOAT_PORT;
		/*
		 * Also update pending connections or they will be deleted if uniqueids
		 * option is set.
		 */
		update_pending(st, st);
	}

	/*
	 * Find valid interface according to local port (500/4500)
	 */
	if ((c->spd.this.host_port == NAT_T_IKE_FLOAT_PORT && !c->interface->ike_float)
	||  (c->spd.this.host_port != NAT_T_IKE_FLOAT_PORT &&  c->interface->ike_float))
	{
		for (i = interfaces; i !=  NULL; i = i->next)
		{
			if (sameaddr(&c->interface->addr, &i->addr)
			&& i->ike_float != c->interface->ike_float)
			{
				DBG(DBG_NATT,
					DBG_log("NAT-T: using interface %s:%d", i->rname,
						i->ike_float ? NAT_T_IKE_FLOAT_PORT : pluto_port);
				)
				c->interface = i;
				break;
			}
		}
	}
}

struct _new_kernel_mapp_nfo {
		u_int32_t reqid;
		u_int32_t spi;
		ip_address *addr;
};

static void nat_t_new_kernel_mapp (struct state *st, void *data)
{
	connection_t *c = st->st_connection;
	struct _new_kernel_mapp_nfo *nfo = (struct _new_kernel_mapp_nfo *)data;

	if (c != NULL && st->st_esp.present
		&&  nfo->spi == st->st_esp.our_spi
		&&  nfo->reqid == c->spd.reqid)
	{
		u_int16_t port = ntohs(portof(nfo->addr));

		DBG(DBG_NATT, {
			char text_said[SATOT_BUF];
			char olda[ADDRTOT_BUF];
			char newa[ADDRTOT_BUF];
			ip_said said;

			initsaid(&c->spd.that.host_addr, nfo->spi, SA_ESP, &said);
			satot(&said, 0, text_said, SATOT_BUF);
			addrtot(&c->spd.that.host_addr, 0, olda, ADDRTOT_BUF);
			addrtot(nfo->addr, 0, newa, ADDRTOT_BUF);

			DBG_log("new kernel mapping %s %s:%d %s:%d",
					text_said, olda, c->spd.that.host_port, newa, port);
		})

		nat_traversal_new_mapping(&c->spd.that.host_addr, c->spd.that.host_port,
								  nfo->addr, port);
	}
}

void process_nat_t_new_mapping(u_int32_t reqid, u_int32_t spi,
							   ip_address *new_end)
{
	struct _new_kernel_mapp_nfo nfo = {
		.reqid = reqid,
		.spi = spi,
		.addr = new_end,
	};
	for_each_state((void *)nat_t_new_kernel_mapp, &nfo);
}