1 /* $NetBSD: pcap-bt-linux.c,v 1.8 2024/09/02 15:33:37 christos Exp $ */
2
3 /*
4 * Copyright (c) 2006 Paolo Abeni (Italy)
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. The name of the author may not be used to endorse or promote
17 * products derived from this software without specific prior written
18 * permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
24 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
26 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
30 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 *
32 * Bluetooth sniffing API implementation for Linux platform
33 * By Paolo Abeni <paolo.abeni@email.it>
34 *
35 */
36 #include <sys/cdefs.h>
37 __RCSID("$NetBSD: pcap-bt-linux.c,v 1.8 2024/09/02 15:33:37 christos Exp $");
38
39 #include <config.h>
40
41 #include "pcap-int.h"
42 #include "pcap-bt-linux.h"
43 #include "pcap/bluetooth.h"
44 #include "diag-control.h"
45
46 #include <errno.h>
47 #include <stdlib.h>
48 #include <unistd.h>
49 #include <fcntl.h>
50 #include <string.h>
51 #include <sys/ioctl.h>
52 #include <sys/socket.h>
53 #include <arpa/inet.h>
54
55 #include <bluetooth/bluetooth.h>
56 #include <bluetooth/hci.h>
57
58 #define BT_IFACE "bluetooth"
59 #define BT_CTRL_SIZE 128
60
61 /* forward declaration */
62 static int bt_activate(pcap_t *);
63 static int bt_read_linux(pcap_t *, int , pcap_handler , u_char *);
64 static int bt_inject_linux(pcap_t *, const void *, int);
65 static int bt_setdirection_linux(pcap_t *, pcap_direction_t);
66 static int bt_stats_linux(pcap_t *, struct pcap_stat *);
67
68 /*
69 * Private data for capturing on Linux Bluetooth devices.
70 */
71 struct pcap_bt {
72 int dev_id; /* device ID of device we're bound to */
73 };
74
75 int
bt_findalldevs(pcap_if_list_t * devlistp,char * err_str)76 bt_findalldevs(pcap_if_list_t *devlistp, char *err_str)
77 {
78 struct hci_dev_list_req *dev_list;
79 struct hci_dev_req *dev_req;
80 int sock;
81 unsigned i;
82 int ret = 0;
83
84 sock = socket(AF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI);
85 if (sock < 0)
86 {
87 /* if bluetooth is not supported this is not fatal*/
88 if (errno == EAFNOSUPPORT)
89 return 0;
90 pcapint_fmt_errmsg_for_errno(err_str, PCAP_ERRBUF_SIZE,
91 errno, "Can't open raw Bluetooth socket");
92 return PCAP_ERROR;
93 }
94
95 dev_list = malloc(HCI_MAX_DEV * sizeof(*dev_req) + sizeof(*dev_list));
96 if (!dev_list)
97 {
98 snprintf(err_str, PCAP_ERRBUF_SIZE, "Can't allocate %zu bytes for Bluetooth device list",
99 HCI_MAX_DEV * sizeof(*dev_req) + sizeof(*dev_list));
100 ret = PCAP_ERROR;
101 goto done;
102 }
103
104 /*
105 * Zero the complete header, which is larger than dev_num because of tail
106 * padding, to silence Valgrind, which overshoots validating that dev_num
107 * has been set.
108 * https://github.com/the-tcpdump-group/libpcap/issues/1083
109 * https://bugs.kde.org/show_bug.cgi?id=448464
110 */
111 memset(dev_list, 0, sizeof(*dev_list));
112 dev_list->dev_num = HCI_MAX_DEV;
113
114 if (ioctl(sock, HCIGETDEVLIST, (void *) dev_list) < 0)
115 {
116 pcapint_fmt_errmsg_for_errno(err_str, PCAP_ERRBUF_SIZE,
117 errno, "Can't get Bluetooth device list via ioctl");
118 ret = PCAP_ERROR;
119 goto free;
120 }
121
122 dev_req = dev_list->dev_req;
123 for (i = 0; i < dev_list->dev_num; i++, dev_req++) {
124 char dev_name[20], dev_descr[40];
125
126 snprintf(dev_name, sizeof(dev_name), BT_IFACE"%u", dev_req->dev_id);
127 snprintf(dev_descr, sizeof(dev_descr), "Bluetooth adapter number %u", i);
128
129 /*
130 * Bluetooth is a wireless technology.
131 * XXX - if there's the notion of associating with a
132 * network, and we can determine whether the interface
133 * is associated with a network, check that and set
134 * the status to PCAP_IF_CONNECTION_STATUS_CONNECTED
135 * or PCAP_IF_CONNECTION_STATUS_DISCONNECTED.
136 */
137 if (pcapint_add_dev(devlistp, dev_name, PCAP_IF_WIRELESS, dev_descr, err_str) == NULL)
138 {
139 ret = PCAP_ERROR;
140 break;
141 }
142 }
143
144 free:
145 free(dev_list);
146
147 done:
148 close(sock);
149 return ret;
150 }
151
152 pcap_t *
bt_create(const char * device,char * ebuf,int * is_ours)153 bt_create(const char *device, char *ebuf, int *is_ours)
154 {
155 const char *cp;
156 char *cpend;
157 long devnum;
158 pcap_t *p;
159
160 /* Does this look like a Bluetooth device? */
161 cp = strrchr(device, '/');
162 if (cp == NULL)
163 cp = device;
164 /* Does it begin with BT_IFACE? */
165 if (strncmp(cp, BT_IFACE, sizeof BT_IFACE - 1) != 0) {
166 /* Nope, doesn't begin with BT_IFACE */
167 *is_ours = 0;
168 return NULL;
169 }
170 /* Yes - is BT_IFACE followed by a number? */
171 cp += sizeof BT_IFACE - 1;
172 devnum = strtol(cp, &cpend, 10);
173 if (cpend == cp || *cpend != '\0') {
174 /* Not followed by a number. */
175 *is_ours = 0;
176 return NULL;
177 }
178 if (devnum < 0) {
179 /* Followed by a non-valid number. */
180 *is_ours = 0;
181 return NULL;
182 }
183
184 /* OK, it's probably ours. */
185 *is_ours = 1;
186
187 p = PCAP_CREATE_COMMON(ebuf, struct pcap_bt);
188 if (p == NULL)
189 return (NULL);
190
191 p->activate_op = bt_activate;
192 return (p);
193 }
194
195 static int
bt_activate(pcap_t * handle)196 bt_activate(pcap_t* handle)
197 {
198 struct pcap_bt *handlep = handle->priv;
199 struct sockaddr_hci addr;
200 int opt;
201 int dev_id;
202 struct hci_filter flt;
203 int err = PCAP_ERROR;
204
205 /* get bt interface id */
206 if (sscanf(handle->opt.device, BT_IFACE"%d", &dev_id) != 1)
207 {
208 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
209 "Can't get Bluetooth device index from %s",
210 handle->opt.device);
211 return PCAP_ERROR;
212 }
213
214 /*
215 * Turn a negative snapshot value (invalid), a snapshot value of
216 * 0 (unspecified), or a value bigger than the normal maximum
217 * value, into the maximum allowed value.
218 *
219 * If some application really *needs* a bigger snapshot
220 * length, we should just increase MAXIMUM_SNAPLEN.
221 */
222 if (handle->snapshot <= 0 || handle->snapshot > MAXIMUM_SNAPLEN)
223 handle->snapshot = MAXIMUM_SNAPLEN;
224
225 /* Initialize some components of the pcap structure. */
226 handle->bufsize = BT_CTRL_SIZE+sizeof(pcap_bluetooth_h4_header)+handle->snapshot;
227 handle->linktype = DLT_BLUETOOTH_HCI_H4_WITH_PHDR;
228
229 handle->read_op = bt_read_linux;
230 handle->inject_op = bt_inject_linux;
231 handle->setfilter_op = pcapint_install_bpf_program; /* no kernel filtering */
232 handle->setdirection_op = bt_setdirection_linux;
233 handle->set_datalink_op = NULL; /* can't change data link type */
234 handle->getnonblock_op = pcapint_getnonblock_fd;
235 handle->setnonblock_op = pcapint_setnonblock_fd;
236 handle->stats_op = bt_stats_linux;
237 handlep->dev_id = dev_id;
238
239 /* Create HCI socket */
240 handle->fd = socket(AF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI);
241 if (handle->fd < 0) {
242 pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
243 errno, "Can't create raw socket");
244 return PCAP_ERROR;
245 }
246
247 handle->buffer = malloc(handle->bufsize);
248 if (!handle->buffer) {
249 pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
250 errno, "Can't allocate dump buffer");
251 goto close_fail;
252 }
253
254 opt = 1;
255 if (setsockopt(handle->fd, SOL_HCI, HCI_DATA_DIR, &opt, sizeof(opt)) < 0) {
256 pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
257 errno, "Can't enable data direction info");
258 goto close_fail;
259 }
260
261 opt = 1;
262 if (setsockopt(handle->fd, SOL_HCI, HCI_TIME_STAMP, &opt, sizeof(opt)) < 0) {
263 pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
264 errno, "Can't enable time stamp");
265 goto close_fail;
266 }
267
268 /* Setup filter, do not call hci function to avoid dependence on
269 * external libs */
270 memset(&flt, 0, sizeof(flt));
271 memset((void *) &flt.type_mask, 0xff, sizeof(flt.type_mask));
272 memset((void *) &flt.event_mask, 0xff, sizeof(flt.event_mask));
273 if (setsockopt(handle->fd, SOL_HCI, HCI_FILTER, &flt, sizeof(flt)) < 0) {
274 pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
275 errno, "Can't set filter");
276 goto close_fail;
277 }
278
279
280 /* Bind socket to the HCI device */
281 addr.hci_family = AF_BLUETOOTH;
282 addr.hci_dev = handlep->dev_id;
283 #ifdef HAVE_STRUCT_SOCKADDR_HCI_HCI_CHANNEL
284 addr.hci_channel = HCI_CHANNEL_RAW;
285 #endif
286 if (bind(handle->fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
287 pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
288 errno, "Can't attach to device %d", handlep->dev_id);
289 goto close_fail;
290 }
291
292 if (handle->opt.rfmon) {
293 /*
294 * Monitor mode doesn't apply to Bluetooth devices.
295 */
296 err = PCAP_ERROR_RFMON_NOTSUP;
297 goto close_fail;
298 }
299
300 if (handle->opt.buffer_size != 0) {
301 /*
302 * Set the socket buffer size to the specified value.
303 */
304 if (setsockopt(handle->fd, SOL_SOCKET, SO_RCVBUF,
305 &handle->opt.buffer_size,
306 sizeof(handle->opt.buffer_size)) == -1) {
307 pcapint_fmt_errmsg_for_errno(handle->errbuf,
308 errno, PCAP_ERRBUF_SIZE, "SO_RCVBUF");
309 goto close_fail;
310 }
311 }
312
313 handle->selectable_fd = handle->fd;
314 return 0;
315
316 close_fail:
317 pcapint_cleanup_live_common(handle);
318 return err;
319 }
320
321 static int
bt_read_linux(pcap_t * handle,int max_packets _U_,pcap_handler callback,u_char * user)322 bt_read_linux(pcap_t *handle, int max_packets _U_, pcap_handler callback, u_char *user)
323 {
324 struct cmsghdr *cmsg;
325 struct msghdr msg;
326 struct iovec iv;
327 ssize_t ret;
328 struct pcap_pkthdr pkth;
329 pcap_bluetooth_h4_header* bthdr;
330 u_char *pktd;
331 int in = 0;
332
333 pktd = (u_char *)handle->buffer + BT_CTRL_SIZE;
334 bthdr = (pcap_bluetooth_h4_header*)(void *)pktd;
335 iv.iov_base = pktd + sizeof(pcap_bluetooth_h4_header);
336 iv.iov_len = handle->snapshot;
337
338 memset(&msg, 0, sizeof(msg));
339 msg.msg_iov = &iv;
340 msg.msg_iovlen = 1;
341 msg.msg_control = handle->buffer;
342 msg.msg_controllen = BT_CTRL_SIZE;
343
344 /* ignore interrupt system call error */
345 do {
346 if (handle->break_loop)
347 {
348 handle->break_loop = 0;
349 return PCAP_ERROR_BREAK;
350 }
351 ret = recvmsg(handle->fd, &msg, 0);
352 } while ((ret == -1) && (errno == EINTR));
353
354 if (ret < 0) {
355 if (errno == EAGAIN || errno == EWOULDBLOCK) {
356 /* Nonblocking mode, no data */
357 return 0;
358 }
359 pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
360 errno, "Can't receive packet");
361 return PCAP_ERROR;
362 }
363
364 pkth.caplen = (bpf_u_int32)ret;
365
366 /* get direction and timestamp*/
367 cmsg = CMSG_FIRSTHDR(&msg);
368 while (cmsg) {
369 switch (cmsg->cmsg_type) {
370 case HCI_CMSG_DIR:
371 memcpy(&in, CMSG_DATA(cmsg), sizeof in);
372 break;
373 case HCI_CMSG_TSTAMP:
374 memcpy(&pkth.ts, CMSG_DATA(cmsg),
375 sizeof pkth.ts);
376 break;
377 }
378 // for musl libc CMSG_NXTHDR()
379 DIAG_OFF_SIGN_COMPARE
380 cmsg = CMSG_NXTHDR(&msg, cmsg);
381 DIAG_ON_SIGN_COMPARE
382 }
383 switch (handle->direction) {
384
385 case PCAP_D_IN:
386 if (!in)
387 return 0;
388 break;
389
390 case PCAP_D_OUT:
391 if (in)
392 return 0;
393 break;
394
395 default:
396 break;
397 }
398
399 bthdr->direction = htonl(in != 0);
400 pkth.caplen+=sizeof(pcap_bluetooth_h4_header);
401 pkth.len = pkth.caplen;
402 if (handle->fcode.bf_insns == NULL ||
403 pcapint_filter(handle->fcode.bf_insns, pktd, pkth.len, pkth.caplen)) {
404 callback(user, &pkth, pktd);
405 return 1;
406 }
407 return 0; /* didn't pass filter */
408 }
409
410 static int
bt_inject_linux(pcap_t * handle,const void * buf _U_,int size _U_)411 bt_inject_linux(pcap_t *handle, const void *buf _U_, int size _U_)
412 {
413 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
414 "Packet injection is not supported on Bluetooth devices");
415 return (-1);
416 }
417
418
419 static int
bt_stats_linux(pcap_t * handle,struct pcap_stat * stats)420 bt_stats_linux(pcap_t *handle, struct pcap_stat *stats)
421 {
422 struct pcap_bt *handlep = handle->priv;
423 int ret;
424 struct hci_dev_info dev_info;
425 struct hci_dev_stats * s = &dev_info.stat;
426 dev_info.dev_id = handlep->dev_id;
427
428 /* ignore eintr */
429 do {
430 ret = ioctl(handle->fd, HCIGETDEVINFO, (void *)&dev_info);
431 } while ((ret == -1) && (errno == EINTR));
432
433 if (ret < 0) {
434 pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
435 errno, "Can't get stats via ioctl");
436 return (-1);
437
438 }
439
440 /* we receive both rx and tx frames, so cumulate all stats */
441 stats->ps_recv = s->evt_rx + s->acl_rx + s->sco_rx + s->cmd_tx +
442 s->acl_tx +s->sco_tx;
443 stats->ps_drop = s->err_rx + s->err_tx;
444 stats->ps_ifdrop = 0;
445 return 0;
446 }
447
448 static int
bt_setdirection_linux(pcap_t * p,pcap_direction_t d)449 bt_setdirection_linux(pcap_t *p, pcap_direction_t d)
450 {
451 /*
452 * It's guaranteed, at this point, that d is a valid
453 * direction value.
454 */
455 p->direction = d;
456 return 0;
457 }
458