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