libnfc  1.7.1
nfc-relay.c
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1 /*-
2  * Free/Libre Near Field Communication (NFC) library
3  *
4  * Libnfc historical contributors:
5  * Copyright (C) 2009 Roel Verdult
6  * Copyright (C) 2009-2013 Romuald Conty
7  * Copyright (C) 2010-2012 Romain Tartière
8  * Copyright (C) 2010-2013 Philippe Teuwen
9  * Copyright (C) 2012-2013 Ludovic Rousseau
10  * See AUTHORS file for a more comprehensive list of contributors.
11  * Additional contributors of this file:
12  *
13  * Redistribution and use in source and binary forms, with or without
14  * modification, are permitted provided that the following conditions are met:
15  * 1) Redistributions of source code must retain the above copyright notice,
16  * this list of conditions and the following disclaimer.
17  * 2 )Redistributions in binary form must reproduce the above copyright
18  * notice, this list of conditions and the following disclaimer in the
19  * documentation and/or other materials provided with the distribution.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
22  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
25  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
26  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
27  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
29  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
30  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
31  * POSSIBILITY OF SUCH DAMAGE.
32  *
33  * Note that this license only applies on the examples, NFC library itself is under LGPL
34  *
35  */
36 
42 #ifdef HAVE_CONFIG_H
43 # include "config.h"
44 #endif /* HAVE_CONFIG_H */
45 
46 #include <inttypes.h>
47 #include <stdio.h>
48 #include <stdlib.h>
49 #include <stdint.h>
50 #include <string.h>
51 #include <signal.h>
52 
53 #include <nfc/nfc.h>
54 
55 #include "utils/nfc-utils.h"
56 
57 #define MAX_FRAME_LEN 264
58 #define MAX_DEVICE_COUNT 2
59 
60 static uint8_t abtReaderRx[MAX_FRAME_LEN];
61 static uint8_t abtReaderRxPar[MAX_FRAME_LEN];
62 static int szReaderRxBits;
63 static uint8_t abtTagRx[MAX_FRAME_LEN];
64 static uint8_t abtTagRxPar[MAX_FRAME_LEN];
65 static int szTagRxBits;
66 static nfc_device *pndReader;
67 static nfc_device *pndTag;
68 static bool quitting = false;
69 
70 static void
71 intr_hdlr(int sig)
72 {
73  (void) sig;
74  printf("\nQuitting...\n");
75  quitting = true;
76  return;
77 }
78 
79 static void
80 print_usage(char *argv[])
81 {
82  printf("Usage: %s [OPTIONS]\n", argv[0]);
83  printf("Options:\n");
84  printf("\t-h\tHelp. Print this message.\n");
85  printf("\t-q\tQuiet mode. Suppress output of READER and EMULATOR data (improves timing).\n");
86 }
87 
88 int
89 main(int argc, char *argv[])
90 {
91  int arg;
92  bool quiet_output = false;
93  const char *acLibnfcVersion = nfc_version();
94 
95  // Get commandline options
96  for (arg = 1; arg < argc; arg++) {
97  if (0 == strcmp(argv[arg], "-h")) {
98  print_usage(argv);
99  exit(EXIT_SUCCESS);
100  } else if (0 == strcmp(argv[arg], "-q")) {
101  quiet_output = true;
102  } else {
103  ERR("%s is not supported option.", argv[arg]);
104  print_usage(argv);
105  exit(EXIT_FAILURE);
106  }
107  }
108 
109  // Display libnfc version
110  printf("%s uses libnfc %s\n", argv[0], acLibnfcVersion);
111 
112 #ifdef WIN32
113  signal(SIGINT, (void (__cdecl *)(int)) intr_hdlr);
114 #else
115  signal(SIGINT, intr_hdlr);
116 #endif
117 
118  nfc_context *context;
119  nfc_init(&context);
120  if (context == NULL) {
121  ERR("Unable to init libnfc (malloc)");
122  exit(EXIT_FAILURE);
123  }
124  nfc_connstring connstrings[MAX_DEVICE_COUNT];
125  // List available devices
126  size_t szFound = nfc_list_devices(context, connstrings, MAX_DEVICE_COUNT);
127 
128  if (szFound < 2) {
129  ERR("%" PRIdPTR " device found but two opened devices are needed to relay NFC.", szFound);
130  nfc_exit(context);
131  exit(EXIT_FAILURE);
132  }
133 
134  // Try to open the NFC emulator device
135  pndTag = nfc_open(context, connstrings[0]);
136  if (pndTag == NULL) {
137  ERR("Error opening NFC emulator device");
138  nfc_exit(context);
139  exit(EXIT_FAILURE);
140  }
141 
142  printf("Hint: tag <---> initiator (relay) <---> target (relay) <---> original reader\n\n");
143 
144  printf("NFC emulator device: %s opened\n", nfc_device_get_name(pndTag));
145  printf("[+] Try to break out the auto-emulation, this requires a second reader!\n");
146  printf("[+] To do this, please send any command after the anti-collision\n");
147  printf("[+] For example, send a RATS command or use the \"nfc-anticol\" tool\n");
148 
149  nfc_target nt = {
150  .nm = {
151  .nmt = NMT_ISO14443A,
152  .nbr = NBR_UNDEFINED,
153  },
154  .nti = {
155  .nai = {
156  .abtAtqa = { 0x04, 0x00 },
157  .abtUid = { 0x08, 0xad, 0xbe, 0xef },
158  .btSak = 0x20,
159  .szUidLen = 4,
160  .szAtsLen = 0,
161  },
162  },
163  };
164 
165  if ((szReaderRxBits = nfc_target_init(pndTag, &nt, abtReaderRx, sizeof(abtReaderRx), 0)) < 0) {
166  ERR("%s", "Initialization of NFC emulator failed");
167  nfc_close(pndTag);
168  nfc_exit(context);
169  exit(EXIT_FAILURE);
170  }
171  printf("%s", "Configuring emulator settings...");
172  if ((nfc_device_set_property_bool(pndTag, NP_HANDLE_CRC, false) < 0) ||
174  nfc_perror(pndTag, "nfc_device_set_property_bool");
175  nfc_close(pndTag);
176  nfc_exit(context);
177  exit(EXIT_FAILURE);
178  }
179  printf("%s", "Done, emulated tag is initialized");
180 
181  // Try to open the NFC reader
182  pndReader = nfc_open(context, connstrings[1]);
183  if (pndReader == NULL) {
184  printf("Error opening NFC reader device\n");
185  nfc_close(pndTag);
186  nfc_exit(context);
187  exit(EXIT_FAILURE);
188  }
189 
190  printf("NFC reader device: %s opened", nfc_device_get_name(pndReader));
191  printf("%s", "Configuring NFC reader settings...");
192 
193  if (nfc_initiator_init(pndReader) < 0) {
194  nfc_perror(pndReader, "nfc_initiator_init");
195  nfc_close(pndTag);
196  nfc_close(pndReader);
197  nfc_exit(context);
198  exit(EXIT_FAILURE);
199  }
200  if ((nfc_device_set_property_bool(pndReader, NP_HANDLE_CRC, false) < 0) ||
201  (nfc_device_set_property_bool(pndReader, NP_HANDLE_PARITY, false) < 0) ||
202  (nfc_device_set_property_bool(pndReader, NP_ACCEPT_INVALID_FRAMES, true)) < 0) {
203  nfc_perror(pndReader, "nfc_device_set_property_bool");
204  nfc_close(pndTag);
205  nfc_close(pndReader);
206  nfc_exit(context);
207  exit(EXIT_FAILURE);
208  }
209  printf("%s", "Done, relaying frames now!");
210 
211  while (!quitting) {
212  // Test if we received a frame from the reader
213  if ((szReaderRxBits = nfc_target_receive_bits(pndTag, abtReaderRx, sizeof(abtReaderRx), abtReaderRxPar)) > 0) {
214  // Drop down the field before sending a REQA command and start a new session
215  if (szReaderRxBits == 7 && abtReaderRx[0] == 0x26) {
216  // Drop down field for a very short time (original tag will reboot)
217  if (nfc_device_set_property_bool(pndReader, NP_ACTIVATE_FIELD, false) < 0) {
218  nfc_perror(pndReader, "nfc_device_set_property_bool");
219  nfc_close(pndTag);
220  nfc_close(pndReader);
221  nfc_exit(context);
222  exit(EXIT_FAILURE);
223  }
224  if (!quiet_output)
225  printf("\n");
226  if (nfc_device_set_property_bool(pndReader, NP_ACTIVATE_FIELD, true) < 0) {
227  nfc_perror(pndReader, "nfc_device_set_property_bool");
228  nfc_close(pndTag);
229  nfc_close(pndReader);
230  nfc_exit(context);
231  exit(EXIT_FAILURE);
232  }
233  }
234  // Print the reader frame to the screen
235  if (!quiet_output) {
236  printf("R: ");
237  print_hex_par(abtReaderRx, (size_t) szReaderRxBits, abtReaderRxPar);
238  }
239  // Forward the frame to the original tag
240  if ((szTagRxBits = nfc_initiator_transceive_bits
241  (pndReader, abtReaderRx, (size_t) szReaderRxBits, abtReaderRxPar, abtTagRx, sizeof(abtTagRx), abtTagRxPar)) > 0) {
242  // Redirect the answer back to the reader
243  if (nfc_target_send_bits(pndTag, abtTagRx, szTagRxBits, abtTagRxPar) < 0) {
244  nfc_perror(pndTag, "nfc_target_send_bits");
245  nfc_close(pndTag);
246  nfc_close(pndReader);
247  nfc_exit(context);
248  exit(EXIT_FAILURE);
249  }
250  // Print the tag frame to the screen
251  if (!quiet_output) {
252  printf("T: ");
253  print_hex_par(abtTagRx, szTagRxBits, abtTagRxPar);
254  }
255  }
256  }
257  }
258 
259  nfc_close(pndTag);
260  nfc_close(pndReader);
261  nfc_exit(context);
262  exit(EXIT_SUCCESS);
263 }
nfc_initiator_init
int nfc_initiator_init(nfc_device *pnd)
Initialize NFC device as initiator (reader)
Definition: nfc.c:452
nfc_init
void nfc_init(nfc_context **context)
Initialize libnfc. This function must be called before calling any other libnfc function.
Definition: nfc.c:192
nfc_context
NFC library context Struct which contains internal options, references, pointers, etc....
Definition: nfc-internal.h:175
nfc_device
NFC device information.
Definition: nfc-internal.h:190
nfc_version
const char * nfc_version(void)
Returns the library version.
Definition: nfc.c:1218
nfc_target_init
int nfc_target_init(nfc_device *pnd, nfc_target *pnt, uint8_t *pbtRx, const size_t szRx, int timeout)
Initialize NFC device as an emulated tag.
Definition: nfc.c:933
NP_HANDLE_CRC
@ NP_HANDLE_CRC
Definition: nfc-types.h:93
NP_ACCEPT_INVALID_FRAMES
@ NP_ACCEPT_INVALID_FRAMES
Definition: nfc-types.h:118
nfc_exit
void nfc_exit(nfc_context *context)
Deinitialize libnfc. Should be called after closing all open devices and before your application term...
Definition: nfc.c:209
nfc_target
NFC target structure.
Definition: nfc-types.h:328
nfc_target_receive_bits
int nfc_target_receive_bits(nfc_device *pnd, uint8_t *pbtRx, const size_t szRx, uint8_t *pbtRxPar)
Receive bit-frames.
Definition: nfc.c:1071
nfc_initiator_transceive_bits
int nfc_initiator_transceive_bits(nfc_device *pnd, const uint8_t *pbtTx, const size_t szTxBits, const uint8_t *pbtTxPar, uint8_t *pbtRx, const size_t szRx, uint8_t *pbtRxPar)
Transceive raw bit-frames to a target.
Definition: nfc.c:807
nfc_connstring
char nfc_connstring[NFC_BUFSIZE_CONNSTRING]
Definition: nfc-types.h:62
nfc_device_get_name
const char * nfc_device_get_name(nfc_device *pnd)
Returns the device name.
Definition: nfc.c:1164
nfc_open
nfc_device * nfc_open(nfc_context *context, const nfc_connstring connstring)
Open a NFC device.
Definition: nfc.c:238
nfc_perror
void nfc_perror(const nfc_device *pnd, const char *pcString)
Display the last error occured on a nfc_device.
Definition: nfc.c:1138
nfc_list_devices
size_t nfc_list_devices(nfc_context *context, nfc_connstring connstrings[], const size_t connstrings_len)
Scan for discoverable supported devices (ie. only available for some drivers)
Definition: nfc.c:317
ERR
#define ERR(...)
Print a error message.
Definition: nfc-utils.h:85
nfc_target_send_bits
int nfc_target_send_bits(nfc_device *pnd, const uint8_t *pbtTx, const size_t szTxBits, const uint8_t *pbtTxPar)
Send raw bit-frames.
Definition: nfc.c:1049
nfc_close
void nfc_close(nfc_device *pnd)
Close from a NFC device.
Definition: nfc.c:300
nfc-utils.h
Provide some examples shared functions like print, parity calculation, options parsing.
NP_HANDLE_PARITY
@ NP_HANDLE_PARITY
Definition: nfc-types.h:101
nfc_device_set_property_bool
int nfc_device_set_property_bool(nfc_device *pnd, const nfc_property property, const bool bEnable)
Set a device's boolean-property value.
Definition: nfc.c:426
nfc.h
libnfc interface
NP_ACTIVATE_FIELD
@ NP_ACTIVATE_FIELD
Definition: nfc-types.h:104