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1/*
2 This file is part of GNUnet.
3 Copyright (C) 2010-2015, 2018 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 * @file util/nt.c
22 * @brief LAN interface scanning to determine IPs in LAN
23 * @author Christian Grothoff
24 * @author Matthias Wachs
25 */
26#include "platform.h"
27#include "gnunet_util_lib.h"
28
29/**
30 * How frequently do we scan the interfaces for changes to the addresses?
31 */
32#define INTERFACE_PROCESSING_INTERVAL GNUNET_TIME_relative_multiply ( \
33 GNUNET_TIME_UNIT_MINUTES, 2)
34
35
36const char *
37GNUNET_NT_to_string (enum GNUNET_NetworkType net)
38{
39 switch (net)
40 {
41 case GNUNET_NT_UNSPECIFIED:
42 return "UNSPECIFIED";
43
44 case GNUNET_NT_LOOPBACK:
45 return "LOOPBACK";
46
47 case GNUNET_NT_LAN:
48 return "LAN";
49
50 case GNUNET_NT_WAN:
51 return "WAN";
52
53 case GNUNET_NT_WLAN:
54 return "WLAN";
55
56 case GNUNET_NT_BT:
57 return "BLUETOOTH";
58
59 default:
60 return NULL;
61 }
62}
63
64
65/**
66 * We keep a list of our local networks so we can answer
67 * LAN vs. WAN questions. Note: WLAN is not detected yet.
68 * (maybe we can do that heuristically based on interface
69 * name in the future?).
70 */
71struct NT_Network
72{
73 /**
74 * Kept in a DLL.
75 */
76 struct NT_Network *next;
77
78 /**
79 * Kept in a DLL.
80 */
81 struct NT_Network *prev;
82
83 /**
84 * Network address.
85 */
86 struct sockaddr *network;
87
88 /**
89 * Netmask to determine what is in the LAN.
90 */
91 struct sockaddr *netmask;
92
93 /**
94 * How long are @e network and @e netmask?
95 */
96 socklen_t length;
97};
98
99
100/**
101 * Handle to the interface scanner.
102 */
103struct GNUNET_NT_InterfaceScanner
104{
105 /**
106 * Head of LAN networks list.
107 */
108 struct NT_Network *net_head;
109
110 /**
111 * Tail of LAN networks list.
112 */
113 struct NT_Network *net_tail;
114
115 /**
116 * Task for periodically refreshing our LAN network list.
117 */
118 struct GNUNET_SCHEDULER_Task *interface_task;
119};
120
121
122/**
123 * Delete all entries from the current network list.
124 *
125 * @param is scanner to clean up
126 */
127static void
128delete_networks (struct GNUNET_NT_InterfaceScanner *is)
129{
130 struct NT_Network *cur;
131
132 while (NULL != (cur = is->net_head))
133 {
134 GNUNET_CONTAINER_DLL_remove (is->net_head,
135 is->net_tail,
136 cur);
137 GNUNET_free (cur);
138 }
139}
140
141
142/**
143 * Function invoked for each interface found. Adds the interface's
144 * network addresses to the respective DLL, so we can distinguish
145 * between LAN and WAN.
146 *
147 * @param cls closure with the `struct GNUNET_NT_InterfaceScanner`
148 * @param name name of the interface (can be NULL for unknown)
149 * @param isDefault is this presumably the default interface
150 * @param addr address of this interface (can be NULL for unknown or unassigned)
151 * @param broadcast_addr the broadcast address (can be NULL for unknown or unassigned)
152 * @param netmask the network mask (can be NULL for unknown or unassigned)
153 * @param addrlen length of the address
154 * @return #GNUNET_OK to continue iteration
155 */
156static int
157interface_proc (void *cls,
158 const char *name,
159 int isDefault,
160 const struct sockaddr *addr,
161 const struct sockaddr *broadcast_addr,
162 const struct sockaddr *netmask,
163 socklen_t addrlen)
164{
165 struct GNUNET_NT_InterfaceScanner *is = cls;
166 /* Calculate network */
167 struct NT_Network *net = NULL;
168
169 (void) name;
170 (void) isDefault;
171 (void) broadcast_addr;
172
173 /* Skipping IPv4 loopback addresses since we have special check */
174 if (addr->sa_family == AF_INET)
175 {
176 const struct sockaddr_in *a4 = (const struct sockaddr_in *) addr;
177
178 if ((a4->sin_addr.s_addr & htonl (0xff000000)) == htonl (0x7f000000))
179 return GNUNET_OK;
180 }
181 /* Skipping IPv6 loopback addresses since we have special check */
182 if (addr->sa_family == AF_INET6)
183 {
184 const struct sockaddr_in6 *a6 = (const struct sockaddr_in6 *) addr;
185 if (IN6_IS_ADDR_LOOPBACK (&a6->sin6_addr))
186 return GNUNET_OK;
187 }
188
189 if (addr->sa_family == AF_INET)
190 {
191 const struct sockaddr_in *addr4 = (const struct sockaddr_in *) addr;
192 const struct sockaddr_in *netmask4 = (const struct sockaddr_in *) netmask;
193 struct sockaddr_in *tmp;
194 struct sockaddr_in network4;
195
196 net = GNUNET_malloc (sizeof(struct NT_Network) + 2 * sizeof(struct
197 sockaddr_in));
198 tmp = (struct sockaddr_in *) &net[1];
199 net->network = (struct sockaddr *) &tmp[0];
200 net->netmask = (struct sockaddr *) &tmp[1];
201 net->length = addrlen;
202
203 memset (&network4,
204 0,
205 sizeof(network4));
206 network4.sin_family = AF_INET;
207#if HAVE_SOCKADDR_IN_SIN_LEN
208 network4.sin_len = sizeof(network4);
209#endif
210 network4.sin_addr.s_addr = (addr4->sin_addr.s_addr
211 & netmask4->sin_addr.s_addr);
212
213 GNUNET_memcpy (net->netmask,
214 netmask4,
215 sizeof(struct sockaddr_in));
216 GNUNET_memcpy (net->network,
217 &network4,
218 sizeof(struct sockaddr_in));
219 }
220
221 if (addr->sa_family == AF_INET6)
222 {
223 const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6 *) addr;
224 const struct sockaddr_in6 *netmask6 = (const struct sockaddr_in6 *) netmask;
225 struct sockaddr_in6 *tmp;
226 struct sockaddr_in6 network6;
227
228 net = GNUNET_malloc (sizeof(struct NT_Network) + 2 * sizeof(struct
229 sockaddr_in6));
230 tmp = (struct sockaddr_in6 *) &net[1];
231 net->network = (struct sockaddr *) &tmp[0];
232 net->netmask = (struct sockaddr *) &tmp[1];
233 net->length = addrlen;
234
235 memset (&network6, 0, sizeof(network6));
236 network6.sin6_family = AF_INET6;
237#if HAVE_SOCKADDR_IN_SIN_LEN
238 network6.sin6_len = sizeof(network6);
239#endif
240 unsigned int c = 0;
241 uint32_t *addr_elem = (uint32_t *) &addr6->sin6_addr;
242 uint32_t *mask_elem = (uint32_t *) &netmask6->sin6_addr;
243 uint32_t *net_elem = (uint32_t *) &network6.sin6_addr;
244 for (c = 0; c < 4; c++)
245 net_elem[c] = addr_elem[c] & mask_elem[c];
246
247 GNUNET_memcpy (net->netmask,
248 netmask6,
249 sizeof(struct sockaddr_in6));
250 GNUNET_memcpy (net->network,
251 &network6,
252 sizeof(struct sockaddr_in6));
253 }
254 if (NULL == net)
255 return GNUNET_OK; /* odd / unsupported address family */
256
257 /* Store in list */
258#if VERBOSE_NT
259 char *netmask = GNUNET_strdup (GNUNET_a2s ((struct sockaddr *) net->netmask,
260 addrlen));
261 GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG,
262 "nt",
263 "Adding network `%s', netmask `%s'\n",
264 GNUNET_a2s ((struct sockaddr *) net->network,
265 addrlen),
266 netmask);
267 GNUNET_free (netmask);
268#endif
269 GNUNET_CONTAINER_DLL_insert (is->net_head,
270 is->net_tail,
271 net);
272
273 return GNUNET_OK;
274}
275
276
277/**
278 * Periodically get list of network addresses from our interfaces.
279 *
280 * @param cls closure
281 */
282static void
283get_addresses (void *cls)
284{
285 struct GNUNET_NT_InterfaceScanner *is = cls;
286
287 is->interface_task = NULL;
288 delete_networks (is);
289 GNUNET_OS_network_interfaces_list (&interface_proc,
290 is);
291 is->interface_task = GNUNET_SCHEDULER_add_delayed (
292 INTERFACE_PROCESSING_INTERVAL,
293 &get_addresses,
294 is);
295}
296
297
298/**
299 * Returns where the address is located: LAN or WAN or ...
300 *
301 * @param is the interface scanner handle
302 * @param addr address
303 * @param addrlen address length
304 * @return type of the network the address belongs to
305 */
306enum GNUNET_NetworkType
307GNUNET_NT_scanner_get_type (struct GNUNET_NT_InterfaceScanner *is,
308 const struct sockaddr *addr,
309 socklen_t addrlen)
310{
311 struct NT_Network *cur = is->net_head;
312 enum GNUNET_NetworkType type = GNUNET_NT_UNSPECIFIED;
313
314 switch (addr->sa_family)
315 {
316 case AF_UNIX:
317 type = GNUNET_NT_LOOPBACK;
318 break;
319
320 case AF_INET:
321 {
322 const struct sockaddr_in *a4 = (const struct sockaddr_in *) addr;
323
324 if ((a4->sin_addr.s_addr & htonl (0xff000000)) == htonl (0x7f000000))
325 type = GNUNET_NT_LOOPBACK;
326 break;
327 }
328
329 case AF_INET6:
330 {
331 const struct sockaddr_in6 *a6 = (const struct sockaddr_in6 *) addr;
332
333 if (IN6_IS_ADDR_LOOPBACK (&a6->sin6_addr))
334 type = GNUNET_NT_LOOPBACK;
335 break;
336 }
337
338 default:
339 GNUNET_break (0);
340 break;
341 }
342
343 /* Check local networks */
344 while ((NULL != cur) && (GNUNET_NT_UNSPECIFIED == type))
345 {
346 if (addrlen != cur->length)
347 {
348 cur = cur->next;
349 continue;
350 }
351 if (addr->sa_family == AF_INET)
352 {
353 const struct sockaddr_in *a4 = (const struct sockaddr_in *) addr;
354 const struct sockaddr_in *net4 = (const struct
355 sockaddr_in *) cur->network;
356 const struct sockaddr_in *mask4 = (const struct
357 sockaddr_in *) cur->netmask;
358
359 if (((a4->sin_addr.s_addr & mask4->sin_addr.s_addr)) ==
360 net4->sin_addr.s_addr)
361 type = GNUNET_NT_LAN;
362 }
363 if (addr->sa_family == AF_INET6)
364 {
365 const struct sockaddr_in6 *a6 = (const struct sockaddr_in6 *) addr;
366 const struct sockaddr_in6 *net6 = (const struct
367 sockaddr_in6 *) cur->network;
368 const struct sockaddr_in6 *mask6 = (const struct
369 sockaddr_in6 *) cur->netmask;
370
371 int res = GNUNET_YES;
372 int c = 0;
373 uint32_t *addr_elem = (uint32_t *) &a6->sin6_addr;
374 uint32_t *mask_elem = (uint32_t *) &mask6->sin6_addr;
375 uint32_t *net_elem = (uint32_t *) &net6->sin6_addr;
376 for (c = 0; c < 4; c++)
377 if ((addr_elem[c] & mask_elem[c]) != net_elem[c])
378 res = GNUNET_NO;
379
380 if (res == GNUNET_YES)
381 type = GNUNET_NT_LAN;
382 }
383 cur = cur->next;
384 }
385
386 /* no local network found for this address, default: WAN */
387 if (type == GNUNET_NT_UNSPECIFIED)
388 type = GNUNET_NT_WAN;
389 GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG,
390 "nt-scanner-api",
391 "`%s' is in network `%s'\n",
392 GNUNET_a2s (addr,
393 addrlen),
394 GNUNET_NT_to_string (type));
395 return type;
396}
397
398
399/**
400 * Initialize the interface scanner.
401 *
402 * @return interface scanner
403 */
404struct GNUNET_NT_InterfaceScanner *
405GNUNET_NT_scanner_init ()
406{
407 struct GNUNET_NT_InterfaceScanner *is;
408
409 is = GNUNET_new (struct GNUNET_NT_InterfaceScanner);
410 GNUNET_OS_network_interfaces_list (&interface_proc,
411 is);
412 is->interface_task = GNUNET_SCHEDULER_add_delayed (
413 INTERFACE_PROCESSING_INTERVAL,
414 &get_addresses,
415 is);
416 return is;
417}
418
419
420/**
421 * Client is done with the interface scanner, release resources.
422 *
423 * @param is handle to release
424 */
425void
426GNUNET_NT_scanner_done (struct GNUNET_NT_InterfaceScanner *is)
427{
428 if (NULL != is->interface_task)
429 {
430 GNUNET_SCHEDULER_cancel (is->interface_task);
431 is->interface_task = NULL;
432 }
433 delete_networks (is);
434 GNUNET_free (is);
435}
436
437
438/* end of nt.c */
generated by cgit v1.2.3 (git 2.39.1) at 2024-05-20 11:30:45 +0000