aboutsummaryrefslogtreecommitdiff
path: root/src/nat/nat_api.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/nat/nat_api.c')
-rw-r--r--src/nat/nat_api.c709
1 files changed, 0 insertions, 709 deletions
diff --git a/src/nat/nat_api.c b/src/nat/nat_api.c
deleted file mode 100644
index 4622b1428..000000000
--- a/src/nat/nat_api.c
+++ /dev/null
@@ -1,709 +0,0 @@
1/*
2 This file is part of GNUnet.
3 Copyright (C) 2007-2017 GNUnet e.V.
4
5 GNUnet is free software: you can redistribute it and/or modify it
6 under the terms of the GNU Affero General Public License as published
7 by the Free Software Foundation, either version 3 of the License,
8 or (at your option) any later version.
9
10 GNUnet is distributed in the hope that it will be useful, but
11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Affero General Public License for more details.
14
15 You should have received a copy of the GNU Affero General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>.
17
18 SPDX-License-Identifier: AGPL3.0-or-later
19 */
20
21/**
22 * @author Christian Grothoff
23 * @author Milan Bouchet-Valat
24 *
25 * @file nat/nat_api.c
26 * Service for handling UPnP and NAT-PMP port forwarding
27 * and external IP address retrieval
28 */
29#include "platform.h"
30#include "gnunet_nat_service.h"
31#include "nat.h"
32#include "nat_stun.h"
33
34
35/**
36 * Entry in DLL of addresses of this peer.
37 */
38struct AddrEntry
39{
40 /**
41 * DLL.
42 */
43 struct AddrEntry *next;
44
45 /**
46 * DLL.
47 */
48 struct AddrEntry *prev;
49
50 /**
51 * Place where the application can store data (on add,
52 * and retrieve on remove).
53 */
54 void *app_ctx;
55
56 /**
57 * Address class of the address.
58 */
59 enum GNUNET_NAT_AddressClass ac;
60
61 /**
62 * Number of bytes that follow.
63 */
64 socklen_t addrlen;
65};
66
67
68/**
69 * Handle for active NAT registrations.
70 */
71struct GNUNET_NAT_Handle
72{
73 /**
74 * Configuration we use.
75 */
76 const struct GNUNET_CONFIGURATION_Handle *cfg;
77
78 /**
79 * Message queue for communicating with the NAT service.
80 */
81 struct GNUNET_MQ_Handle *mq;
82
83 /**
84 * Our registration message.
85 */
86 struct GNUNET_MessageHeader *reg;
87
88 /**
89 * Head of address DLL.
90 */
91 struct AddrEntry *ae_head;
92
93 /**
94 * Tail of address DLL.
95 */
96 struct AddrEntry *ae_tail;
97
98 /**
99 * Function to call when our addresses change.
100 */
101 GNUNET_NAT_AddressCallback address_callback;
102
103 /**
104 * Function to call when another peer requests connection reversal.
105 */
106 GNUNET_NAT_ReversalCallback reversal_callback;
107
108 /**
109 * Closure for the various callbacks.
110 */
111 void *callback_cls;
112
113 /**
114 * Task scheduled to reconnect to the service.
115 */
116 struct GNUNET_SCHEDULER_Task *reconnect_task;
117
118 /**
119 * How long to wait until we reconnect.
120 */
121 struct GNUNET_TIME_Relative reconnect_delay;
122};
123
124
125/**
126 * Task to connect to the NAT service.
127 *
128 * @param cls our `struct GNUNET_NAT_Handle *`
129 */
130static void
131do_connect (void *cls);
132
133
134/**
135 * Task to connect to the NAT service.
136 *
137 * @param nh handle to reconnect
138 */
139static void
140reconnect (struct GNUNET_NAT_Handle *nh)
141{
142 struct AddrEntry *ae;
143
144 if (NULL != nh->mq)
145 {
146 GNUNET_MQ_destroy (nh->mq);
147 nh->mq = NULL;
148 }
149 while (NULL != (ae = nh->ae_head))
150 {
151 GNUNET_CONTAINER_DLL_remove (nh->ae_head, nh->ae_tail, ae);
152 nh->address_callback (nh->callback_cls,
153 &ae->app_ctx,
154 GNUNET_NO,
155 ae->ac,
156 (const struct sockaddr *) &ae[1],
157 ae->addrlen);
158 GNUNET_free (ae);
159 }
160 nh->reconnect_delay = GNUNET_TIME_STD_BACKOFF (nh->reconnect_delay);
161 nh->reconnect_task =
162 GNUNET_SCHEDULER_add_delayed (nh->reconnect_delay, &do_connect, nh);
163}
164
165
166/**
167 * Check connection reversal request.
168 *
169 * @param cls our `struct GNUNET_NAT_Handle`
170 * @param crm the message
171 * @return #GNUNET_OK if @a crm is well-formed
172 */
173static int
174check_connection_reversal_request (
175 void *cls,
176 const struct GNUNET_NAT_ConnectionReversalRequestedMessage *crm)
177{
178 if (ntohs (crm->header.size) != sizeof(*crm) + sizeof(struct sockaddr_in))
179 {
180 GNUNET_break (0);
181 return GNUNET_SYSERR;
182 }
183 return GNUNET_OK;
184}
185
186
187/**
188 * Handle connection reversal request.
189 *
190 * @param cls our `struct GNUNET_NAT_Handle`
191 * @param crm the message
192 */
193static void
194handle_connection_reversal_request (
195 void *cls,
196 const struct GNUNET_NAT_ConnectionReversalRequestedMessage *crm)
197{
198 struct GNUNET_NAT_Handle *nh = cls;
199
200 nh->reversal_callback (nh->callback_cls,
201 (const struct sockaddr *) &crm[1],
202 sizeof(struct sockaddr_in));
203}
204
205
206/**
207 * Check address change notification.
208 *
209 * @param cls our `struct GNUNET_NAT_Handle`
210 * @param acn the message
211 * @return #GNUNET_OK if @a crm is well-formed
212 */
213static int
214check_address_change_notification (
215 void *cls,
216 const struct GNUNET_NAT_AddressChangeNotificationMessage *acn)
217{
218 size_t alen = ntohs (acn->header.size) - sizeof(*acn);
219
220 switch (alen)
221 {
222 case sizeof(struct sockaddr_in): {
223 const struct sockaddr_in *s4 = (const struct sockaddr_in *) &acn[1];
224 if (AF_INET != s4->sin_family)
225 {
226 GNUNET_break (0);
227 return GNUNET_SYSERR;
228 }
229 }
230 break;
231
232 case sizeof(struct sockaddr_in6): {
233 const struct sockaddr_in6 *s6 = (const struct sockaddr_in6 *) &acn[1];
234 if (AF_INET6 != s6->sin6_family)
235 {
236 GNUNET_break (0);
237 return GNUNET_SYSERR;
238 }
239 }
240 break;
241
242 default:
243 GNUNET_break (0);
244 return GNUNET_SYSERR;
245 }
246 return GNUNET_OK;
247}
248
249
250/**
251 * Handle connection reversal request.
252 *
253 * @param cls our `struct GNUNET_NAT_Handle`
254 * @param acn the message
255 */
256static void
257handle_address_change_notification (
258 void *cls,
259 const struct GNUNET_NAT_AddressChangeNotificationMessage *acn)
260{
261 struct GNUNET_NAT_Handle *nh = cls;
262 size_t alen = ntohs (acn->header.size) - sizeof(*acn);
263 const struct sockaddr *sa = (const struct sockaddr *) &acn[1];
264 enum GNUNET_NAT_AddressClass ac;
265 struct AddrEntry *ae;
266
267 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
268 "Received address change notification\n");
269 ac = (enum GNUNET_NAT_AddressClass) ntohl (acn->addr_class);
270 if (GNUNET_YES == ntohl (acn->add_remove))
271 {
272 ae = GNUNET_malloc (sizeof(*ae) + alen);
273 ae->ac = ac;
274 ae->addrlen = alen;
275 GNUNET_memcpy (&ae[1], sa, alen);
276 GNUNET_CONTAINER_DLL_insert (nh->ae_head, nh->ae_tail, ae);
277 nh->address_callback (nh->callback_cls,
278 &ae->app_ctx,
279 ntohl (acn->add_remove),
280 ac,
281 sa,
282 alen);
283 }
284 else
285 {
286 for (ae = nh->ae_head; NULL != ae; ae = ae->next)
287 if ((ae->addrlen == alen) && (0 == memcmp (&ae[1], sa, alen)))
288 break;
289 if (NULL == ae)
290 {
291 GNUNET_break (0);
292 reconnect (nh);
293 return;
294 }
295 GNUNET_CONTAINER_DLL_remove (nh->ae_head, nh->ae_tail, ae);
296 nh->address_callback (nh->callback_cls,
297 &ae->app_ctx,
298 ntohl (acn->add_remove),
299 ac,
300 sa,
301 alen);
302 GNUNET_free (ae);
303 }
304}
305
306
307/**
308 * Handle queue errors by reconnecting to NAT.
309 *
310 * @param cls the `struct GNUNET_NAT_Handle *`
311 * @param error details about the error
312 */
313static void
314mq_error_handler (void *cls, enum GNUNET_MQ_Error error)
315{
316 struct GNUNET_NAT_Handle *nh = cls;
317
318 reconnect (nh);
319}
320
321
322/**
323 * Task to connect to the NAT service.
324 *
325 * @param cls our `struct GNUNET_NAT_Handle *`
326 */
327static void
328do_connect (void *cls)
329{
330 struct GNUNET_NAT_Handle *nh = cls;
331 struct GNUNET_MQ_MessageHandler handlers[] =
332 { GNUNET_MQ_hd_var_size (connection_reversal_request,
333 GNUNET_MESSAGE_TYPE_NAT_CONNECTION_REVERSAL_REQUESTED,
334 struct
335 GNUNET_NAT_ConnectionReversalRequestedMessage,
336 nh),
337 GNUNET_MQ_hd_var_size (address_change_notification,
338 GNUNET_MESSAGE_TYPE_NAT_ADDRESS_CHANGE,
339 struct GNUNET_NAT_AddressChangeNotificationMessage,
340 nh),
341 GNUNET_MQ_handler_end () };
342 struct GNUNET_MQ_Envelope *env;
343
344 nh->reconnect_task = NULL;
345 nh->mq =
346 GNUNET_CLIENT_connect (nh->cfg, "nat", handlers, &mq_error_handler, nh);
347 if (NULL == nh->mq)
348 {
349 reconnect (nh);
350 return;
351 }
352 env = GNUNET_MQ_msg_copy (nh->reg);
353 GNUNET_MQ_send (nh->mq, env);
354}
355
356
357/**
358 * Attempt to enable port redirection and detect public IP address
359 * contacting UPnP or NAT-PMP routers on the local network. Use @a
360 * addr to specify to which of the local host's addresses should the
361 * external port be mapped. The port is taken from the corresponding
362 * sockaddr_in[6] field. The NAT module should call the given @a
363 * address_callback for any 'plausible' external address.
364 *
365 * @param cfg configuration to use
366 * @param config_section name of the configuration section for optionsx
367 * @param proto protocol this is about, IPPROTO_TCP or IPPROTO_UDP
368 * @param num_addrs number of addresses in @a addrs
369 * @param addrs list of local addresses packets should be redirected to
370 * @param addrlens actual lengths of the addresses in @a addrs
371 * @param address_callback function to call every time the public IP address changes
372 * @param reversal_callback function to call if someone wants connection reversal from us,
373 * NULL if connection reversal is not supported
374 * @param callback_cls closure for callbacks
375 * @return NULL on error, otherwise handle that can be used to unregister
376 */
377struct GNUNET_NAT_Handle *
378GNUNET_NAT_register (const struct GNUNET_CONFIGURATION_Handle *cfg,
379 const char *config_section,
380 uint8_t proto,
381 unsigned int num_addrs,
382 const struct sockaddr **addrs,
383 const socklen_t *addrlens,
384 GNUNET_NAT_AddressCallback address_callback,
385 GNUNET_NAT_ReversalCallback reversal_callback,
386 void *callback_cls)
387{
388 struct GNUNET_NAT_Handle *nh;
389 struct GNUNET_NAT_RegisterMessage *rm;
390 size_t len;
391 size_t str_len;
392 char *off;
393
394 len = 0;
395 for (unsigned int i = 0; i < num_addrs; i++)
396 len += addrlens[i];
397 str_len = strlen (config_section) + 1;
398 len += str_len;
399 if ((len > GNUNET_MAX_MESSAGE_SIZE - sizeof(*rm)) ||
400 (num_addrs > UINT16_MAX))
401 {
402 GNUNET_break (0);
403 return NULL;
404 }
405 rm = GNUNET_malloc (sizeof(*rm) + len);
406 rm->header.size = htons (sizeof(*rm) + len);
407 rm->header.type = htons (GNUNET_MESSAGE_TYPE_NAT_REGISTER);
408 rm->flags = GNUNET_NAT_RF_NONE;
409 if (NULL != address_callback)
410 rm->flags |= GNUNET_NAT_RF_ADDRESSES;
411 if (NULL != reversal_callback)
412 rm->flags |= GNUNET_NAT_RF_REVERSAL;
413 rm->proto = proto;
414 rm->str_len = htons (str_len);
415 rm->num_addrs = htons ((uint16_t) num_addrs);
416 off = (char *) &rm[1];
417 for (unsigned int i = 0; i < num_addrs; i++)
418 {
419 switch (addrs[i]->sa_family)
420 {
421 case AF_INET:
422 if (sizeof(struct sockaddr_in) != addrlens[i])
423 {
424 GNUNET_break (0);
425 GNUNET_free (rm);
426 return NULL;
427 }
428 break;
429
430 case AF_INET6:
431 if (sizeof(struct sockaddr_in6) != addrlens[i])
432 {
433 GNUNET_break (0);
434 GNUNET_free (rm);
435 return NULL;
436 }
437 break;
438
439#if AF_UNIX
440 case AF_UNIX:
441 if (sizeof(struct sockaddr_un) != addrlens[i])
442 {
443 GNUNET_break (0);
444 GNUNET_free (rm);
445 return NULL;
446 }
447 break;
448#endif
449 default:
450 GNUNET_break (0);
451 GNUNET_free (rm);
452 return NULL;
453 }
454 GNUNET_memcpy (off, addrs[i], addrlens[i]);
455 off += addrlens[i];
456 }
457 GNUNET_memcpy (off, config_section, str_len);
458
459 nh = GNUNET_new (struct GNUNET_NAT_Handle);
460 nh->reg = &rm->header;
461 nh->cfg = cfg;
462 nh->address_callback = address_callback;
463 nh->reversal_callback = reversal_callback;
464 nh->callback_cls = callback_cls;
465 do_connect (nh);
466 return nh;
467}
468
469
470/**
471 * Check if an incoming message is a STUN message.
472 *
473 * @param data the packet
474 * @param len the length of the packet in @a data
475 * @return #GNUNET_YES if @a data is a STUN packet,
476 * #GNUNET_NO if the packet is invalid (not a stun packet)
477 */
478static int
479test_stun_packet (const void *data, size_t len)
480{
481 const struct stun_header *hdr;
482 const struct stun_attr *attr;
483 uint32_t advertised_message_size;
484 uint32_t message_magic_cookie;
485
486 /* On entry, 'len' is the length of the UDP payload. After the
487 * initial checks it becomes the size of unprocessed options,
488 * while 'data' is advanced accordingly.
489 */
490 if (len < sizeof(struct stun_header))
491 {
492 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
493 "STUN packet too short (only %d, wanting at least %d)\n",
494 (int) len,
495 (int) sizeof(struct stun_header));
496 return GNUNET_NO;
497 }
498 hdr = (const struct stun_header *) data;
499 /* Skip header as it is already in hdr */
500 len -= sizeof(struct stun_header);
501 data += sizeof(struct stun_header);
502
503 /* len as advertised in the message */
504 advertised_message_size = ntohs (hdr->msglen);
505
506 message_magic_cookie = ntohl (hdr->magic);
507 /* Compare if the cookie match */
508 if (STUN_MAGIC_COOKIE != message_magic_cookie)
509 {
510 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Invalid magic cookie for STUN\n");
511 return GNUNET_NO;
512 }
513
514 if (advertised_message_size > len)
515 {
516 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
517 "Scrambled STUN packet length (got %d, expecting %d)\n",
518 advertised_message_size,
519 (int) len);
520 return GNUNET_NO;
521 }
522 len = advertised_message_size;
523 while (len > 0)
524 {
525 if (len < sizeof(struct stun_attr))
526 {
527 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
528 "Attribute too short in STUN packet (got %d, expecting %d)\n",
529 (int) len,
530 (int) sizeof(struct stun_attr));
531 return GNUNET_NO;
532 }
533 attr = (const struct stun_attr *) data;
534
535 /* compute total attribute length */
536 advertised_message_size = ntohs (attr->len) + sizeof(struct stun_attr);
537
538 /* Check if we still have space in our buffer */
539 if (advertised_message_size > len)
540 {
541 GNUNET_log (
542 GNUNET_ERROR_TYPE_DEBUG,
543 "Inconsistent Attribute (length %d exceeds remaining msg len %d)\n",
544 advertised_message_size,
545 (int) len);
546 return GNUNET_NO;
547 }
548 data += advertised_message_size;
549 len -= advertised_message_size;
550 }
551 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
552 "STUN Packet, msg %04x, length: %d\n",
553 ntohs (hdr->msgtype),
554 advertised_message_size);
555 return GNUNET_OK;
556}
557
558
559/**
560 * Handle an incoming STUN message. This function is useful as
561 * some GNUnet service may be listening on a UDP port and might
562 * thus receive STUN messages while trying to receive other data.
563 * In this case, this function can be used to process replies
564 * to STUN requests.
565 *
566 * The function does some basic sanity checks on packet size and
567 * content, try to extract a bit of information.
568 *
569 * At the moment this only processes BIND requests, and returns the
570 * externally visible address of the request to the rest of the
571 * NAT logic.
572 *
573 * @param nh handle to the NAT service
574 * @param sender_addr address from which we got @a data
575 * @param sender_addr_len number of bytes in @a sender_addr
576 * @param data the packet
577 * @param data_size number of bytes in @a data
578 * @return #GNUNET_OK on success
579 * #GNUNET_NO if the packet is not a STUN packet
580 * #GNUNET_SYSERR on internal error handling the packet
581 */
582int
583GNUNET_NAT_stun_handle_packet (struct GNUNET_NAT_Handle *nh,
584 const struct sockaddr *sender_addr,
585 size_t sender_addr_len,
586 const void *data,
587 size_t data_size)
588{
589 struct GNUNET_MQ_Envelope *env;
590 struct GNUNET_NAT_HandleStunMessage *hsn;
591 char *buf;
592
593 if (GNUNET_YES != test_stun_packet (data, data_size))
594 return GNUNET_NO;
595 if (NULL == nh->mq)
596 return GNUNET_SYSERR;
597 env = GNUNET_MQ_msg_extra (hsn,
598 data_size + sender_addr_len,
599 GNUNET_MESSAGE_TYPE_NAT_HANDLE_STUN);
600 hsn->sender_addr_size = htons ((uint16_t) sender_addr_len);
601 hsn->payload_size = htons ((uint16_t) data_size);
602 buf = (char *) &hsn[1];
603 GNUNET_memcpy (buf, sender_addr, sender_addr_len);
604 buf += sender_addr_len;
605 GNUNET_memcpy (buf, data, data_size);
606 GNUNET_MQ_send (nh->mq, env);
607 return GNUNET_OK;
608}
609
610
611/**
612 * Test if the given address is (currently) a plausible IP address for
613 * this peer. Mostly a convenience function so that clients do not
614 * have to explicitly track all IPs that the #GNUNET_NAT_AddressCallback
615 * has returned so far.
616 *
617 * @param nh the handle returned by register
618 * @param addr IP address to test (IPv4 or IPv6)
619 * @param addrlen number of bytes in @a addr
620 * @return #GNUNET_YES if the address is plausible,
621 * #GNUNET_NO if the address is not plausible,
622 * #GNUNET_SYSERR if the address is malformed
623 */
624int
625GNUNET_NAT_test_address (struct GNUNET_NAT_Handle *nh,
626 const void *addr,
627 socklen_t addrlen)
628{
629 struct AddrEntry *ae;
630
631 if ((addrlen != sizeof(struct sockaddr_in)) &&
632 (addrlen != sizeof(struct sockaddr_in6)))
633 {
634 GNUNET_break (0);
635 return GNUNET_SYSERR;
636 }
637 for (ae = nh->ae_head; NULL != ae; ae = ae->next)
638 if ((addrlen == ae->addrlen) && (0 == memcmp (addr, &ae[1], addrlen)))
639 return GNUNET_YES;
640 return GNUNET_NO;
641}
642
643
644/**
645 * We learned about a peer (possibly behind NAT) so run the
646 * gnunet-nat-client to send dummy ICMP responses to cause
647 * that peer to connect to us (connection reversal).
648 *
649 * @param nh handle (used for configuration)
650 * @param local_sa our local address of the peer (IPv4-only)
651 * @param remote_sa the remote address of the peer (IPv4-only)
652 * @return #GNUNET_SYSERR on error,
653 * #GNUNET_NO if connection reversal is unavailable,
654 * #GNUNET_OK otherwise (presumably in progress)
655 */
656int
657GNUNET_NAT_request_reversal (struct GNUNET_NAT_Handle *nh,
658 const struct sockaddr_in *local_sa,
659 const struct sockaddr_in *remote_sa)
660{
661 struct GNUNET_MQ_Envelope *env;
662 struct GNUNET_NAT_RequestConnectionReversalMessage *req;
663 char *buf;
664
665 if (NULL == nh->mq)
666 return GNUNET_SYSERR;
667 GNUNET_break (AF_INET == local_sa->sin_family);
668 GNUNET_break (AF_INET == remote_sa->sin_family);
669 env =
670 GNUNET_MQ_msg_extra (req,
671 2 * sizeof(struct sockaddr_in),
672 GNUNET_MESSAGE_TYPE_NAT_REQUEST_CONNECTION_REVERSAL);
673 req->local_addr_size = htons (sizeof(struct sockaddr_in));
674 req->remote_addr_size = htons (sizeof(struct sockaddr_in));
675 buf = (char *) &req[1];
676 GNUNET_memcpy (buf, local_sa, sizeof(struct sockaddr_in));
677 buf += sizeof(struct sockaddr_in);
678 GNUNET_memcpy (buf, remote_sa, sizeof(struct sockaddr_in));
679 GNUNET_MQ_send (nh->mq, env);
680 return GNUNET_OK;
681}
682
683
684/**
685 * Stop port redirection and public IP address detection for the given
686 * handle. This frees the handle, after having sent the needed
687 * commands to close open ports.
688 *
689 * @param nh the handle to stop
690 */
691void
692GNUNET_NAT_unregister (struct GNUNET_NAT_Handle *nh)
693{
694 if (NULL != nh->mq)
695 {
696 GNUNET_MQ_destroy (nh->mq);
697 nh->mq = NULL;
698 }
699 if (NULL != nh->reconnect_task)
700 {
701 GNUNET_SCHEDULER_cancel (nh->reconnect_task);
702 nh->reconnect_task = NULL;
703 }
704 GNUNET_free (nh->reg);
705 GNUNET_free (nh);
706}
707
708
709/* end of nat_api.c */
generated by cgit v1.2.3 (git 2.39.1) at 2024-04-16 19:04:23 +0000