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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 *, size_t);
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 i, sock;
78 	int ret = 0;
79 
80 	sock  = socket(AF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI);
81 	if (sock < 0)
82 	{
83 		/* if bluetooth is not supported this this is not fatal*/
84 		if (errno == EAFNOSUPPORT)
85 			return 0;
86 		pcap_fmt_errmsg_for_errno(err_str, PCAP_ERRBUF_SIZE,
87 		    errno, "Can't open raw Bluetooth socket");
88 		return -1;
89 	}
90 
91 	dev_list = malloc(HCI_MAX_DEV * sizeof(*dev_req) + sizeof(*dev_list));
92 	if (!dev_list)
93 	{
94 		pcap_snprintf(err_str, PCAP_ERRBUF_SIZE, "Can't allocate %zu bytes for Bluetooth device list",
95 			HCI_MAX_DEV * sizeof(*dev_req) + sizeof(*dev_list));
96 		ret = -1;
97 		goto done;
98 	}
99 
100 	dev_list->dev_num = HCI_MAX_DEV;
101 
102 	if (ioctl(sock, HCIGETDEVLIST, (void *) dev_list) < 0)
103 	{
104 		pcap_fmt_errmsg_for_errno(err_str, PCAP_ERRBUF_SIZE,
105 		    errno, "Can't get Bluetooth device list via ioctl");
106 		ret = -1;
107 		goto free;
108 	}
109 
110 	dev_req = dev_list->dev_req;
111 	for (i = 0; i < dev_list->dev_num; i++, dev_req++) {
112 		char dev_name[20], dev_descr[30];
113 
114 		pcap_snprintf(dev_name, 20, BT_IFACE"%d", dev_req->dev_id);
115 		pcap_snprintf(dev_descr, 30, "Bluetooth adapter number %d", i);
116 
117 		/*
118 		 * Bluetooth is a wireless technology.
119 		 * XXX - if there's the notion of associating with a
120 		 * network, and we can determine whether the interface
121 		 * is associated with a network, check that and set
122 		 * the status to PCAP_IF_CONNECTION_STATUS_CONNECTED
123 		 * or PCAP_IF_CONNECTION_STATUS_DISCONNECTED.
124 		 */
125 		if (add_dev(devlistp, dev_name, PCAP_IF_WIRELESS, dev_descr, err_str)  == NULL)
126 		{
127 			ret = -1;
128 			break;
129 		}
130 	}
131 
132 free:
133 	free(dev_list);
134 
135 done:
136 	close(sock);
137 	return ret;
138 }
139 
140 pcap_t *
bt_create(const char * device,char * ebuf,int * is_ours)141 bt_create(const char *device, char *ebuf, int *is_ours)
142 {
143 	const char *cp;
144 	char *cpend;
145 	long devnum;
146 	pcap_t *p;
147 
148 	/* Does this look like a Bluetooth device? */
149 	cp = strrchr(device, '/');
150 	if (cp == NULL)
151 		cp = device;
152 	/* Does it begin with BT_IFACE? */
153 	if (strncmp(cp, BT_IFACE, sizeof BT_IFACE - 1) != 0) {
154 		/* Nope, doesn't begin with BT_IFACE */
155 		*is_ours = 0;
156 		return NULL;
157 	}
158 	/* Yes - is BT_IFACE followed by a number? */
159 	cp += sizeof BT_IFACE - 1;
160 	devnum = strtol(cp, &cpend, 10);
161 	if (cpend == cp || *cpend != '\0') {
162 		/* Not followed by a number. */
163 		*is_ours = 0;
164 		return NULL;
165 	}
166 	if (devnum < 0) {
167 		/* Followed by a non-valid number. */
168 		*is_ours = 0;
169 		return NULL;
170 	}
171 
172 	/* OK, it's probably ours. */
173 	*is_ours = 1;
174 
175 	p = pcap_create_common(ebuf, sizeof (struct pcap_bt));
176 	if (p == NULL)
177 		return (NULL);
178 
179 	p->activate_op = bt_activate;
180 	return (p);
181 }
182 
183 static int
bt_activate(pcap_t * handle)184 bt_activate(pcap_t* handle)
185 {
186 	struct pcap_bt *handlep = handle->priv;
187 	struct sockaddr_hci addr;
188 	int opt;
189 	int		dev_id;
190 	struct hci_filter	flt;
191 	int err = PCAP_ERROR;
192 
193 	/* get bt interface id */
194 	if (sscanf(handle->opt.device, BT_IFACE"%d", &dev_id) != 1)
195 	{
196 		pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
197 			"Can't get Bluetooth device index from %s",
198 			 handle->opt.device);
199 		return PCAP_ERROR;
200 	}
201 
202 	/*
203 	 * Turn a negative snapshot value (invalid), a snapshot value of
204 	 * 0 (unspecified), or a value bigger than the normal maximum
205 	 * value, into the maximum allowed value.
206 	 *
207 	 * If some application really *needs* a bigger snapshot
208 	 * length, we should just increase MAXIMUM_SNAPLEN.
209 	 */
210 	if (handle->snapshot <= 0 || handle->snapshot > MAXIMUM_SNAPLEN)
211 		handle->snapshot = MAXIMUM_SNAPLEN;
212 
213 	/* Initialize some components of the pcap structure. */
214 	handle->bufsize = BT_CTRL_SIZE+sizeof(pcap_bluetooth_h4_header)+handle->snapshot;
215 	handle->linktype = DLT_BLUETOOTH_HCI_H4_WITH_PHDR;
216 
217 	handle->read_op = bt_read_linux;
218 	handle->inject_op = bt_inject_linux;
219 	handle->setfilter_op = install_bpf_program; /* no kernel filtering */
220 	handle->setdirection_op = bt_setdirection_linux;
221 	handle->set_datalink_op = NULL;	/* can't change data link type */
222 	handle->getnonblock_op = pcap_getnonblock_fd;
223 	handle->setnonblock_op = pcap_setnonblock_fd;
224 	handle->stats_op = bt_stats_linux;
225 	handlep->dev_id = dev_id;
226 
227 	/* Create HCI socket */
228 	handle->fd = socket(AF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI);
229 	if (handle->fd < 0) {
230 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
231 		    errno, "Can't create raw socket");
232 		return PCAP_ERROR;
233 	}
234 
235 	handle->buffer = malloc(handle->bufsize);
236 	if (!handle->buffer) {
237 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
238 		    errno, "Can't allocate dump buffer");
239 		goto close_fail;
240 	}
241 
242 	opt = 1;
243 	if (setsockopt(handle->fd, SOL_HCI, HCI_DATA_DIR, &opt, sizeof(opt)) < 0) {
244 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
245 		    errno, "Can't enable data direction info");
246 		goto close_fail;
247 	}
248 
249 	opt = 1;
250 	if (setsockopt(handle->fd, SOL_HCI, HCI_TIME_STAMP, &opt, sizeof(opt)) < 0) {
251 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
252 		    errno, "Can't enable time stamp");
253 		goto close_fail;
254 	}
255 
256 	/* Setup filter, do not call hci function to avoid dependence on
257 	 * external libs	*/
258 	memset(&flt, 0, sizeof(flt));
259 	memset((void *) &flt.type_mask, 0xff, sizeof(flt.type_mask));
260 	memset((void *) &flt.event_mask, 0xff, sizeof(flt.event_mask));
261 	if (setsockopt(handle->fd, SOL_HCI, HCI_FILTER, &flt, sizeof(flt)) < 0) {
262 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
263 		    errno, "Can't set filter");
264 		goto close_fail;
265 	}
266 
267 
268 	/* Bind socket to the HCI device */
269 	addr.hci_family = AF_BLUETOOTH;
270 	addr.hci_dev = handlep->dev_id;
271 #ifdef HAVE_STRUCT_SOCKADDR_HCI_HCI_CHANNEL
272 	addr.hci_channel = HCI_CHANNEL_RAW;
273 #endif
274 	if (bind(handle->fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
275 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
276 		    errno, "Can't attach to device %d", handlep->dev_id);
277 		goto close_fail;
278 	}
279 
280 	if (handle->opt.rfmon) {
281 		/*
282 		 * Monitor mode doesn't apply to Bluetooth devices.
283 		 */
284 		err = PCAP_ERROR_RFMON_NOTSUP;
285 		goto close_fail;
286 	}
287 
288 	if (handle->opt.buffer_size != 0) {
289 		/*
290 		 * Set the socket buffer size to the specified value.
291 		 */
292 		if (setsockopt(handle->fd, SOL_SOCKET, SO_RCVBUF,
293 		    &handle->opt.buffer_size,
294 		    sizeof(handle->opt.buffer_size)) == -1) {
295 			pcap_fmt_errmsg_for_errno(handle->errbuf,
296 			    errno, PCAP_ERRBUF_SIZE, "SO_RCVBUF");
297 			goto close_fail;
298 		}
299 	}
300 
301 	handle->selectable_fd = handle->fd;
302 	return 0;
303 
304 close_fail:
305 	pcap_cleanup_live_common(handle);
306 	return err;
307 }
308 
309 static int
bt_read_linux(pcap_t * handle,int max_packets _U_,pcap_handler callback,u_char * user)310 bt_read_linux(pcap_t *handle, int max_packets _U_, pcap_handler callback, u_char *user)
311 {
312 	struct cmsghdr *cmsg;
313 	struct msghdr msg;
314 	struct iovec  iv;
315 	ssize_t ret;
316 	struct pcap_pkthdr pkth;
317 	pcap_bluetooth_h4_header* bthdr;
318 	u_char *pktd;
319 	int in = 0;
320 
321 	pktd = (u_char *)handle->buffer + BT_CTRL_SIZE;
322 	bthdr = (pcap_bluetooth_h4_header*)(void *)pktd;
323 	iv.iov_base = pktd + sizeof(pcap_bluetooth_h4_header);
324 	iv.iov_len  = handle->snapshot;
325 
326 	memset(&msg, 0, sizeof(msg));
327 	msg.msg_iov = &iv;
328 	msg.msg_iovlen = 1;
329 	msg.msg_control = handle->buffer;
330 	msg.msg_controllen = BT_CTRL_SIZE;
331 
332 	/* ignore interrupt system call error */
333 	do {
334 		ret = recvmsg(handle->fd, &msg, 0);
335 		if (handle->break_loop)
336 		{
337 			handle->break_loop = 0;
338 			return -2;
339 		}
340 	} while ((ret == -1) && (errno == EINTR));
341 
342 	if (ret < 0) {
343 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
344 		    errno, "Can't receive packet");
345 		return -1;
346 	}
347 
348 	pkth.caplen = ret;
349 
350 	/* get direction and timestamp*/
351 	cmsg = CMSG_FIRSTHDR(&msg);
352 	while (cmsg) {
353 		switch (cmsg->cmsg_type) {
354 			case HCI_CMSG_DIR:
355 				memcpy(&in, CMSG_DATA(cmsg), sizeof in);
356 				break;
357                       	case HCI_CMSG_TSTAMP:
358                       		memcpy(&pkth.ts, CMSG_DATA(cmsg),
359                       		    sizeof pkth.ts);
360 				break;
361 		}
362 		cmsg = CMSG_NXTHDR(&msg, cmsg);
363 	}
364 	if ((in && (handle->direction == PCAP_D_OUT)) ||
365 				((!in) && (handle->direction == PCAP_D_IN)))
366 		return 0;
367 
368 	bthdr->direction = htonl(in != 0);
369 	pkth.caplen+=sizeof(pcap_bluetooth_h4_header);
370 	pkth.len = pkth.caplen;
371 	if (handle->fcode.bf_insns == NULL ||
372 	    bpf_filter(handle->fcode.bf_insns, pktd, pkth.len, pkth.caplen)) {
373 		callback(user, &pkth, pktd);
374 		return 1;
375 	}
376 	return 0;	/* didn't pass filter */
377 }
378 
379 static int
bt_inject_linux(pcap_t * handle,const void * buf _U_,size_t size _U_)380 bt_inject_linux(pcap_t *handle, const void *buf _U_, size_t size _U_)
381 {
382 	pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "inject not supported on "
383     		"bluetooth devices");
384 	return (-1);
385 }
386 
387 
388 static int
bt_stats_linux(pcap_t * handle,struct pcap_stat * stats)389 bt_stats_linux(pcap_t *handle, struct pcap_stat *stats)
390 {
391 	struct pcap_bt *handlep = handle->priv;
392 	int ret;
393 	struct hci_dev_info dev_info;
394 	struct hci_dev_stats * s = &dev_info.stat;
395 	dev_info.dev_id = handlep->dev_id;
396 
397 	/* ignore eintr */
398 	do {
399 		ret = ioctl(handle->fd, HCIGETDEVINFO, (void *)&dev_info);
400 	} while ((ret == -1) && (errno == EINTR));
401 
402 	if (ret < 0) {
403 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
404 		    errno, "Can't get stats via ioctl");
405 		return (-1);
406 
407 	}
408 
409 	/* we receive both rx and tx frames, so comulate all stats */
410 	stats->ps_recv = s->evt_rx + s->acl_rx + s->sco_rx + s->cmd_tx +
411 		s->acl_tx +s->sco_tx;
412 	stats->ps_drop = s->err_rx + s->err_tx;
413 	stats->ps_ifdrop = 0;
414 	return 0;
415 }
416 
417 static int
bt_setdirection_linux(pcap_t * p,pcap_direction_t d)418 bt_setdirection_linux(pcap_t *p, pcap_direction_t d)
419 {
420 	p->direction = d;
421 	return 0;
422 }
423