2 * H.323 extension for NAT alteration.
4 * Copyright (c) 2006 Jing Min Zhao <zhaojingmin@users.sourceforge.net>
5 * Copyright (c) 2006-2012 Patrick McHardy <kaber@trash.net>
7 * This source code is licensed under General Public License version 2.
9 * Based on the 'brute force' H.323 NAT module by
10 * Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
13 #include <linux/module.h>
14 #include <linux/tcp.h>
17 #include <net/netfilter/nf_nat.h>
18 #include <net/netfilter/nf_nat_helper.h>
19 #include <net/netfilter/nf_conntrack_helper.h>
20 #include <net/netfilter/nf_conntrack_expect.h>
21 #include <linux/netfilter/nf_conntrack_h323.h>
23 /****************************************************************************/
24 static int set_addr(struct sk_buff
*skb
, unsigned int protoff
,
25 unsigned char **data
, int dataoff
,
26 unsigned int addroff
, __be32 ip
, __be16 port
)
28 enum ip_conntrack_info ctinfo
;
29 struct nf_conn
*ct
= nf_ct_get(skb
, &ctinfo
);
33 } __attribute__ ((__packed__
)) buf
;
34 const struct tcphdr
*th
;
41 if (ip_hdr(skb
)->protocol
== IPPROTO_TCP
) {
42 if (!nf_nat_mangle_tcp_packet(skb
, ct
, ctinfo
,
43 protoff
, addroff
, sizeof(buf
),
44 (char *) &buf
, sizeof(buf
))) {
45 net_notice_ratelimited("nf_nat_h323: nf_nat_mangle_tcp_packet error\n");
49 /* Relocate data pointer */
50 th
= skb_header_pointer(skb
, ip_hdrlen(skb
),
51 sizeof(_tcph
), &_tcph
);
54 *data
= skb
->data
+ ip_hdrlen(skb
) + th
->doff
* 4 + dataoff
;
56 if (!nf_nat_mangle_udp_packet(skb
, ct
, ctinfo
,
57 protoff
, addroff
, sizeof(buf
),
58 (char *) &buf
, sizeof(buf
))) {
59 net_notice_ratelimited("nf_nat_h323: nf_nat_mangle_udp_packet error\n");
62 /* nf_nat_mangle_udp_packet uses skb_make_writable() to copy
63 * or pull everything in a linear buffer, so we can safely
64 * use the skb pointers now */
65 *data
= skb
->data
+ ip_hdrlen(skb
) + sizeof(struct udphdr
);
71 /****************************************************************************/
72 static int set_h225_addr(struct sk_buff
*skb
, unsigned int protoff
,
73 unsigned char **data
, int dataoff
,
74 TransportAddress
*taddr
,
75 union nf_inet_addr
*addr
, __be16 port
)
77 return set_addr(skb
, protoff
, data
, dataoff
, taddr
->ipAddress
.ip
,
81 /****************************************************************************/
82 static int set_h245_addr(struct sk_buff
*skb
, unsigned protoff
,
83 unsigned char **data
, int dataoff
,
84 H245_TransportAddress
*taddr
,
85 union nf_inet_addr
*addr
, __be16 port
)
87 return set_addr(skb
, protoff
, data
, dataoff
,
88 taddr
->unicastAddress
.iPAddress
.network
,
92 /****************************************************************************/
93 static int set_sig_addr(struct sk_buff
*skb
, struct nf_conn
*ct
,
94 enum ip_conntrack_info ctinfo
,
95 unsigned int protoff
, unsigned char **data
,
96 TransportAddress
*taddr
, int count
)
98 const struct nf_ct_h323_master
*info
= nfct_help_data(ct
);
99 int dir
= CTINFO2DIR(ctinfo
);
102 union nf_inet_addr addr
;
104 for (i
= 0; i
< count
; i
++) {
105 if (get_h225_addr(ct
, *data
, &taddr
[i
], &addr
, &port
)) {
106 if (addr
.ip
== ct
->tuplehash
[dir
].tuple
.src
.u3
.ip
&&
107 port
== info
->sig_port
[dir
]) {
110 /* Fix for Gnomemeeting */
112 get_h225_addr(ct
, *data
, &taddr
[0],
114 (ntohl(addr
.ip
) & 0xff000000) == 0x7f000000)
117 pr_debug("nf_nat_ras: set signal address %pI4:%hu->%pI4:%hu\n",
119 &ct
->tuplehash
[!dir
].tuple
.dst
.u3
.ip
,
120 info
->sig_port
[!dir
]);
121 return set_h225_addr(skb
, protoff
, data
, 0,
123 &ct
->tuplehash
[!dir
].
125 info
->sig_port
[!dir
]);
126 } else if (addr
.ip
== ct
->tuplehash
[dir
].tuple
.dst
.u3
.ip
&&
127 port
== info
->sig_port
[dir
]) {
129 pr_debug("nf_nat_ras: set signal address %pI4:%hu->%pI4:%hu\n",
131 &ct
->tuplehash
[!dir
].tuple
.src
.u3
.ip
,
132 info
->sig_port
[!dir
]);
133 return set_h225_addr(skb
, protoff
, data
, 0,
135 &ct
->tuplehash
[!dir
].
137 info
->sig_port
[!dir
]);
145 /****************************************************************************/
146 static int set_ras_addr(struct sk_buff
*skb
, struct nf_conn
*ct
,
147 enum ip_conntrack_info ctinfo
,
148 unsigned int protoff
, unsigned char **data
,
149 TransportAddress
*taddr
, int count
)
151 int dir
= CTINFO2DIR(ctinfo
);
154 union nf_inet_addr addr
;
156 for (i
= 0; i
< count
; i
++) {
157 if (get_h225_addr(ct
, *data
, &taddr
[i
], &addr
, &port
) &&
158 addr
.ip
== ct
->tuplehash
[dir
].tuple
.src
.u3
.ip
&&
159 port
== ct
->tuplehash
[dir
].tuple
.src
.u
.udp
.port
) {
160 pr_debug("nf_nat_ras: set rasAddress %pI4:%hu->%pI4:%hu\n",
161 &addr
.ip
, ntohs(port
),
162 &ct
->tuplehash
[!dir
].tuple
.dst
.u3
.ip
,
163 ntohs(ct
->tuplehash
[!dir
].tuple
.dst
.u
.udp
.port
));
164 return set_h225_addr(skb
, protoff
, data
, 0, &taddr
[i
],
165 &ct
->tuplehash
[!dir
].tuple
.dst
.u3
,
166 ct
->tuplehash
[!dir
].tuple
.
174 /****************************************************************************/
175 static int nat_rtp_rtcp(struct sk_buff
*skb
, struct nf_conn
*ct
,
176 enum ip_conntrack_info ctinfo
,
177 unsigned int protoff
, unsigned char **data
, int dataoff
,
178 H245_TransportAddress
*taddr
,
179 __be16 port
, __be16 rtp_port
,
180 struct nf_conntrack_expect
*rtp_exp
,
181 struct nf_conntrack_expect
*rtcp_exp
)
183 struct nf_ct_h323_master
*info
= nfct_help_data(ct
);
184 int dir
= CTINFO2DIR(ctinfo
);
186 u_int16_t nated_port
;
188 /* Set expectations for NAT */
189 rtp_exp
->saved_proto
.udp
.port
= rtp_exp
->tuple
.dst
.u
.udp
.port
;
190 rtp_exp
->expectfn
= nf_nat_follow_master
;
192 rtcp_exp
->saved_proto
.udp
.port
= rtcp_exp
->tuple
.dst
.u
.udp
.port
;
193 rtcp_exp
->expectfn
= nf_nat_follow_master
;
194 rtcp_exp
->dir
= !dir
;
196 /* Lookup existing expects */
197 for (i
= 0; i
< H323_RTP_CHANNEL_MAX
; i
++) {
198 if (info
->rtp_port
[i
][dir
] == rtp_port
) {
201 /* Use allocated ports first. This will refresh
203 rtp_exp
->tuple
.dst
.u
.udp
.port
= info
->rtp_port
[i
][dir
];
204 rtcp_exp
->tuple
.dst
.u
.udp
.port
=
205 htons(ntohs(info
->rtp_port
[i
][dir
]) + 1);
207 } else if (info
->rtp_port
[i
][dir
] == 0) {
213 /* Run out of expectations */
214 if (i
>= H323_RTP_CHANNEL_MAX
) {
215 net_notice_ratelimited("nf_nat_h323: out of expectations\n");
219 /* Try to get a pair of ports. */
220 for (nated_port
= ntohs(rtp_exp
->tuple
.dst
.u
.udp
.port
);
221 nated_port
!= 0; nated_port
+= 2) {
224 rtp_exp
->tuple
.dst
.u
.udp
.port
= htons(nated_port
);
225 ret
= nf_ct_expect_related(rtp_exp
);
227 rtcp_exp
->tuple
.dst
.u
.udp
.port
=
228 htons(nated_port
+ 1);
229 ret
= nf_ct_expect_related(rtcp_exp
);
232 else if (ret
!= -EBUSY
) {
233 nf_ct_unexpect_related(rtp_exp
);
237 } else if (ret
!= -EBUSY
) {
243 if (nated_port
== 0) { /* No port available */
244 net_notice_ratelimited("nf_nat_h323: out of RTP ports\n");
249 if (set_h245_addr(skb
, protoff
, data
, dataoff
, taddr
,
250 &ct
->tuplehash
[!dir
].tuple
.dst
.u3
,
251 htons((port
& htons(1)) ? nated_port
+ 1 :
254 info
->rtp_port
[i
][dir
] = rtp_port
;
255 info
->rtp_port
[i
][!dir
] = htons(nated_port
);
257 nf_ct_unexpect_related(rtp_exp
);
258 nf_ct_unexpect_related(rtcp_exp
);
263 pr_debug("nf_nat_h323: expect RTP %pI4:%hu->%pI4:%hu\n",
264 &rtp_exp
->tuple
.src
.u3
.ip
,
265 ntohs(rtp_exp
->tuple
.src
.u
.udp
.port
),
266 &rtp_exp
->tuple
.dst
.u3
.ip
,
267 ntohs(rtp_exp
->tuple
.dst
.u
.udp
.port
));
268 pr_debug("nf_nat_h323: expect RTCP %pI4:%hu->%pI4:%hu\n",
269 &rtcp_exp
->tuple
.src
.u3
.ip
,
270 ntohs(rtcp_exp
->tuple
.src
.u
.udp
.port
),
271 &rtcp_exp
->tuple
.dst
.u3
.ip
,
272 ntohs(rtcp_exp
->tuple
.dst
.u
.udp
.port
));
277 /****************************************************************************/
278 static int nat_t120(struct sk_buff
*skb
, struct nf_conn
*ct
,
279 enum ip_conntrack_info ctinfo
,
280 unsigned int protoff
, unsigned char **data
, int dataoff
,
281 H245_TransportAddress
*taddr
, __be16 port
,
282 struct nf_conntrack_expect
*exp
)
284 int dir
= CTINFO2DIR(ctinfo
);
285 u_int16_t nated_port
= ntohs(port
);
287 /* Set expectations for NAT */
288 exp
->saved_proto
.tcp
.port
= exp
->tuple
.dst
.u
.tcp
.port
;
289 exp
->expectfn
= nf_nat_follow_master
;
292 /* Try to get same port: if not, try to change it. */
293 for (; nated_port
!= 0; nated_port
++) {
296 exp
->tuple
.dst
.u
.tcp
.port
= htons(nated_port
);
297 ret
= nf_ct_expect_related(exp
);
300 else if (ret
!= -EBUSY
) {
306 if (nated_port
== 0) { /* No port available */
307 net_notice_ratelimited("nf_nat_h323: out of TCP ports\n");
312 if (set_h245_addr(skb
, protoff
, data
, dataoff
, taddr
,
313 &ct
->tuplehash
[!dir
].tuple
.dst
.u3
,
314 htons(nated_port
)) < 0) {
315 nf_ct_unexpect_related(exp
);
319 pr_debug("nf_nat_h323: expect T.120 %pI4:%hu->%pI4:%hu\n",
320 &exp
->tuple
.src
.u3
.ip
,
321 ntohs(exp
->tuple
.src
.u
.tcp
.port
),
322 &exp
->tuple
.dst
.u3
.ip
,
323 ntohs(exp
->tuple
.dst
.u
.tcp
.port
));
328 /****************************************************************************/
329 static int nat_h245(struct sk_buff
*skb
, struct nf_conn
*ct
,
330 enum ip_conntrack_info ctinfo
,
331 unsigned int protoff
, unsigned char **data
, int dataoff
,
332 TransportAddress
*taddr
, __be16 port
,
333 struct nf_conntrack_expect
*exp
)
335 struct nf_ct_h323_master
*info
= nfct_help_data(ct
);
336 int dir
= CTINFO2DIR(ctinfo
);
337 u_int16_t nated_port
= ntohs(port
);
339 /* Set expectations for NAT */
340 exp
->saved_proto
.tcp
.port
= exp
->tuple
.dst
.u
.tcp
.port
;
341 exp
->expectfn
= nf_nat_follow_master
;
344 /* Check existing expects */
345 if (info
->sig_port
[dir
] == port
)
346 nated_port
= ntohs(info
->sig_port
[!dir
]);
348 /* Try to get same port: if not, try to change it. */
349 for (; nated_port
!= 0; nated_port
++) {
352 exp
->tuple
.dst
.u
.tcp
.port
= htons(nated_port
);
353 ret
= nf_ct_expect_related(exp
);
356 else if (ret
!= -EBUSY
) {
362 if (nated_port
== 0) { /* No port available */
363 net_notice_ratelimited("nf_nat_q931: out of TCP ports\n");
368 if (set_h225_addr(skb
, protoff
, data
, dataoff
, taddr
,
369 &ct
->tuplehash
[!dir
].tuple
.dst
.u3
,
370 htons(nated_port
)) == 0) {
372 info
->sig_port
[dir
] = port
;
373 info
->sig_port
[!dir
] = htons(nated_port
);
375 nf_ct_unexpect_related(exp
);
379 pr_debug("nf_nat_q931: expect H.245 %pI4:%hu->%pI4:%hu\n",
380 &exp
->tuple
.src
.u3
.ip
,
381 ntohs(exp
->tuple
.src
.u
.tcp
.port
),
382 &exp
->tuple
.dst
.u3
.ip
,
383 ntohs(exp
->tuple
.dst
.u
.tcp
.port
));
388 /****************************************************************************
389 * This conntrack expect function replaces nf_conntrack_q931_expect()
390 * which was set by nf_conntrack_h323.c.
391 ****************************************************************************/
392 static void ip_nat_q931_expect(struct nf_conn
*new,
393 struct nf_conntrack_expect
*this)
395 struct nf_nat_range range
;
397 if (this->tuple
.src
.u3
.ip
!= 0) { /* Only accept calls from GK */
398 nf_nat_follow_master(new, this);
402 /* This must be a fresh one. */
403 BUG_ON(new->status
& IPS_NAT_DONE_MASK
);
405 /* Change src to where master sends to */
406 range
.flags
= NF_NAT_RANGE_MAP_IPS
;
407 range
.min_addr
= range
.max_addr
=
408 new->tuplehash
[!this->dir
].tuple
.src
.u3
;
409 nf_nat_setup_info(new, &range
, NF_NAT_MANIP_SRC
);
411 /* For DST manip, map port here to where it's expected. */
412 range
.flags
= (NF_NAT_RANGE_MAP_IPS
| NF_NAT_RANGE_PROTO_SPECIFIED
);
413 range
.min_proto
= range
.max_proto
= this->saved_proto
;
414 range
.min_addr
= range
.max_addr
=
415 new->master
->tuplehash
[!this->dir
].tuple
.src
.u3
;
416 nf_nat_setup_info(new, &range
, NF_NAT_MANIP_DST
);
419 /****************************************************************************/
420 static int nat_q931(struct sk_buff
*skb
, struct nf_conn
*ct
,
421 enum ip_conntrack_info ctinfo
,
422 unsigned int protoff
, unsigned char **data
,
423 TransportAddress
*taddr
, int idx
,
424 __be16 port
, struct nf_conntrack_expect
*exp
)
426 struct nf_ct_h323_master
*info
= nfct_help_data(ct
);
427 int dir
= CTINFO2DIR(ctinfo
);
428 u_int16_t nated_port
= ntohs(port
);
429 union nf_inet_addr addr
;
431 /* Set expectations for NAT */
432 exp
->saved_proto
.tcp
.port
= exp
->tuple
.dst
.u
.tcp
.port
;
433 exp
->expectfn
= ip_nat_q931_expect
;
436 /* Check existing expects */
437 if (info
->sig_port
[dir
] == port
)
438 nated_port
= ntohs(info
->sig_port
[!dir
]);
440 /* Try to get same port: if not, try to change it. */
441 for (; nated_port
!= 0; nated_port
++) {
444 exp
->tuple
.dst
.u
.tcp
.port
= htons(nated_port
);
445 ret
= nf_ct_expect_related(exp
);
448 else if (ret
!= -EBUSY
) {
454 if (nated_port
== 0) { /* No port available */
455 net_notice_ratelimited("nf_nat_ras: out of TCP ports\n");
460 if (set_h225_addr(skb
, protoff
, data
, 0, &taddr
[idx
],
461 &ct
->tuplehash
[!dir
].tuple
.dst
.u3
,
462 htons(nated_port
)) == 0) {
464 info
->sig_port
[dir
] = port
;
465 info
->sig_port
[!dir
] = htons(nated_port
);
467 /* Fix for Gnomemeeting */
469 get_h225_addr(ct
, *data
, &taddr
[0], &addr
, &port
) &&
470 (ntohl(addr
.ip
) & 0xff000000) == 0x7f000000) {
471 set_h225_addr(skb
, protoff
, data
, 0, &taddr
[0],
472 &ct
->tuplehash
[!dir
].tuple
.dst
.u3
,
473 info
->sig_port
[!dir
]);
476 nf_ct_unexpect_related(exp
);
481 pr_debug("nf_nat_ras: expect Q.931 %pI4:%hu->%pI4:%hu\n",
482 &exp
->tuple
.src
.u3
.ip
,
483 ntohs(exp
->tuple
.src
.u
.tcp
.port
),
484 &exp
->tuple
.dst
.u3
.ip
,
485 ntohs(exp
->tuple
.dst
.u
.tcp
.port
));
490 /****************************************************************************/
491 static void ip_nat_callforwarding_expect(struct nf_conn
*new,
492 struct nf_conntrack_expect
*this)
494 struct nf_nat_range range
;
496 /* This must be a fresh one. */
497 BUG_ON(new->status
& IPS_NAT_DONE_MASK
);
499 /* Change src to where master sends to */
500 range
.flags
= NF_NAT_RANGE_MAP_IPS
;
501 range
.min_addr
= range
.max_addr
=
502 new->tuplehash
[!this->dir
].tuple
.src
.u3
;
503 nf_nat_setup_info(new, &range
, NF_NAT_MANIP_SRC
);
505 /* For DST manip, map port here to where it's expected. */
506 range
.flags
= (NF_NAT_RANGE_MAP_IPS
| NF_NAT_RANGE_PROTO_SPECIFIED
);
507 range
.min_proto
= range
.max_proto
= this->saved_proto
;
508 range
.min_addr
= range
.max_addr
= this->saved_addr
;
509 nf_nat_setup_info(new, &range
, NF_NAT_MANIP_DST
);
512 /****************************************************************************/
513 static int nat_callforwarding(struct sk_buff
*skb
, struct nf_conn
*ct
,
514 enum ip_conntrack_info ctinfo
,
515 unsigned int protoff
,
516 unsigned char **data
, int dataoff
,
517 TransportAddress
*taddr
, __be16 port
,
518 struct nf_conntrack_expect
*exp
)
520 int dir
= CTINFO2DIR(ctinfo
);
521 u_int16_t nated_port
;
523 /* Set expectations for NAT */
524 exp
->saved_addr
= exp
->tuple
.dst
.u3
;
525 exp
->tuple
.dst
.u3
.ip
= ct
->tuplehash
[!dir
].tuple
.dst
.u3
.ip
;
526 exp
->saved_proto
.tcp
.port
= exp
->tuple
.dst
.u
.tcp
.port
;
527 exp
->expectfn
= ip_nat_callforwarding_expect
;
530 /* Try to get same port: if not, try to change it. */
531 for (nated_port
= ntohs(port
); nated_port
!= 0; nated_port
++) {
534 exp
->tuple
.dst
.u
.tcp
.port
= htons(nated_port
);
535 ret
= nf_ct_expect_related(exp
);
538 else if (ret
!= -EBUSY
) {
544 if (nated_port
== 0) { /* No port available */
545 net_notice_ratelimited("nf_nat_q931: out of TCP ports\n");
550 if (!set_h225_addr(skb
, protoff
, data
, dataoff
, taddr
,
551 &ct
->tuplehash
[!dir
].tuple
.dst
.u3
,
552 htons(nated_port
)) == 0) {
553 nf_ct_unexpect_related(exp
);
558 pr_debug("nf_nat_q931: expect Call Forwarding %pI4:%hu->%pI4:%hu\n",
559 &exp
->tuple
.src
.u3
.ip
,
560 ntohs(exp
->tuple
.src
.u
.tcp
.port
),
561 &exp
->tuple
.dst
.u3
.ip
,
562 ntohs(exp
->tuple
.dst
.u
.tcp
.port
));
567 static struct nf_ct_helper_expectfn q931_nat
= {
569 .expectfn
= ip_nat_q931_expect
,
572 static struct nf_ct_helper_expectfn callforwarding_nat
= {
573 .name
= "callforwarding",
574 .expectfn
= ip_nat_callforwarding_expect
,
577 /****************************************************************************/
578 static int __init
init(void)
580 BUG_ON(set_h245_addr_hook
!= NULL
);
581 BUG_ON(set_h225_addr_hook
!= NULL
);
582 BUG_ON(set_sig_addr_hook
!= NULL
);
583 BUG_ON(set_ras_addr_hook
!= NULL
);
584 BUG_ON(nat_rtp_rtcp_hook
!= NULL
);
585 BUG_ON(nat_t120_hook
!= NULL
);
586 BUG_ON(nat_h245_hook
!= NULL
);
587 BUG_ON(nat_callforwarding_hook
!= NULL
);
588 BUG_ON(nat_q931_hook
!= NULL
);
590 RCU_INIT_POINTER(set_h245_addr_hook
, set_h245_addr
);
591 RCU_INIT_POINTER(set_h225_addr_hook
, set_h225_addr
);
592 RCU_INIT_POINTER(set_sig_addr_hook
, set_sig_addr
);
593 RCU_INIT_POINTER(set_ras_addr_hook
, set_ras_addr
);
594 RCU_INIT_POINTER(nat_rtp_rtcp_hook
, nat_rtp_rtcp
);
595 RCU_INIT_POINTER(nat_t120_hook
, nat_t120
);
596 RCU_INIT_POINTER(nat_h245_hook
, nat_h245
);
597 RCU_INIT_POINTER(nat_callforwarding_hook
, nat_callforwarding
);
598 RCU_INIT_POINTER(nat_q931_hook
, nat_q931
);
599 nf_ct_helper_expectfn_register(&q931_nat
);
600 nf_ct_helper_expectfn_register(&callforwarding_nat
);
604 /****************************************************************************/
605 static void __exit
fini(void)
607 RCU_INIT_POINTER(set_h245_addr_hook
, NULL
);
608 RCU_INIT_POINTER(set_h225_addr_hook
, NULL
);
609 RCU_INIT_POINTER(set_sig_addr_hook
, NULL
);
610 RCU_INIT_POINTER(set_ras_addr_hook
, NULL
);
611 RCU_INIT_POINTER(nat_rtp_rtcp_hook
, NULL
);
612 RCU_INIT_POINTER(nat_t120_hook
, NULL
);
613 RCU_INIT_POINTER(nat_h245_hook
, NULL
);
614 RCU_INIT_POINTER(nat_callforwarding_hook
, NULL
);
615 RCU_INIT_POINTER(nat_q931_hook
, NULL
);
616 nf_ct_helper_expectfn_unregister(&q931_nat
);
617 nf_ct_helper_expectfn_unregister(&callforwarding_nat
);
621 /****************************************************************************/
625 MODULE_AUTHOR("Jing Min Zhao <zhaojingmin@users.sourceforge.net>");
626 MODULE_DESCRIPTION("H.323 NAT helper");
627 MODULE_LICENSE("GPL");
628 MODULE_ALIAS("ip_nat_h323");