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 */
59static int bt_activate(pcap_t *);
60static int bt_read_linux(pcap_t *, int , pcap_handler , u_char *);
61static int bt_inject_linux(pcap_t *, const void *, int);
62static int bt_setdirection_linux(pcap_t *, pcap_direction_t);
63static int bt_stats_linux(pcap_t *, struct pcap_stat *);
64
65/*
66 * Private data for capturing on Linux Bluetooth devices.
67 */
68struct pcap_bt {
69	int dev_id;		/* device ID of device we're bound to */
70};
71
72int
73bt_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	/*
102	 * Zero the complete header, which is larger than dev_num because of tail
103	 * padding, to silence Valgrind, which overshoots validating that dev_num
104	 * has been set.
105	 * https://github.com/the-tcpdump-group/libpcap/issues/1083
106	 * https://bugs.kde.org/show_bug.cgi?id=448464
107	 */
108	memset(dev_list, 0, sizeof(*dev_list));
109	dev_list->dev_num = HCI_MAX_DEV;
110
111	if (ioctl(sock, HCIGETDEVLIST, (void *) dev_list) < 0)
112	{
113		pcap_fmt_errmsg_for_errno(err_str, PCAP_ERRBUF_SIZE,
114		    errno, "Can't get Bluetooth device list via ioctl");
115		ret = -1;
116		goto free;
117	}
118
119	dev_req = dev_list->dev_req;
120	for (i = 0; i < dev_list->dev_num; i++, dev_req++) {
121		char dev_name[20], dev_descr[40];
122
123		snprintf(dev_name, sizeof(dev_name), BT_IFACE"%u", dev_req->dev_id);
124		snprintf(dev_descr, sizeof(dev_descr), "Bluetooth adapter number %u", i);
125
126		/*
127		 * Bluetooth is a wireless technology.
128		 * XXX - if there's the notion of associating with a
129		 * network, and we can determine whether the interface
130		 * is associated with a network, check that and set
131		 * the status to PCAP_IF_CONNECTION_STATUS_CONNECTED
132		 * or PCAP_IF_CONNECTION_STATUS_DISCONNECTED.
133		 */
134		if (add_dev(devlistp, dev_name, PCAP_IF_WIRELESS, dev_descr, err_str)  == NULL)
135		{
136			ret = -1;
137			break;
138		}
139	}
140
141free:
142	free(dev_list);
143
144done:
145	close(sock);
146	return ret;
147}
148
149pcap_t *
150bt_create(const char *device, char *ebuf, int *is_ours)
151{
152	const char *cp;
153	char *cpend;
154	long devnum;
155	pcap_t *p;
156
157	/* Does this look like a Bluetooth device? */
158	cp = strrchr(device, '/');
159	if (cp == NULL)
160		cp = device;
161	/* Does it begin with BT_IFACE? */
162	if (strncmp(cp, BT_IFACE, sizeof BT_IFACE - 1) != 0) {
163		/* Nope, doesn't begin with BT_IFACE */
164		*is_ours = 0;
165		return NULL;
166	}
167	/* Yes - is BT_IFACE followed by a number? */
168	cp += sizeof BT_IFACE - 1;
169	devnum = strtol(cp, &cpend, 10);
170	if (cpend == cp || *cpend != '\0') {
171		/* Not followed by a number. */
172		*is_ours = 0;
173		return NULL;
174	}
175	if (devnum < 0) {
176		/* Followed by a non-valid number. */
177		*is_ours = 0;
178		return NULL;
179	}
180
181	/* OK, it's probably ours. */
182	*is_ours = 1;
183
184	p = PCAP_CREATE_COMMON(ebuf, struct pcap_bt);
185	if (p == NULL)
186		return (NULL);
187
188	p->activate_op = bt_activate;
189	return (p);
190}
191
192static int
193bt_activate(pcap_t* handle)
194{
195	struct pcap_bt *handlep = handle->priv;
196	struct sockaddr_hci addr;
197	int opt;
198	int		dev_id;
199	struct hci_filter	flt;
200	int err = PCAP_ERROR;
201
202	/* get bt interface id */
203	if (sscanf(handle->opt.device, BT_IFACE"%d", &dev_id) != 1)
204	{
205		snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
206			"Can't get Bluetooth device index from %s",
207			 handle->opt.device);
208		return PCAP_ERROR;
209	}
210
211	/*
212	 * Turn a negative snapshot value (invalid), a snapshot value of
213	 * 0 (unspecified), or a value bigger than the normal maximum
214	 * value, into the maximum allowed value.
215	 *
216	 * If some application really *needs* a bigger snapshot
217	 * length, we should just increase MAXIMUM_SNAPLEN.
218	 */
219	if (handle->snapshot <= 0 || handle->snapshot > MAXIMUM_SNAPLEN)
220		handle->snapshot = MAXIMUM_SNAPLEN;
221
222	/* Initialize some components of the pcap structure. */
223	handle->bufsize = BT_CTRL_SIZE+sizeof(pcap_bluetooth_h4_header)+handle->snapshot;
224	handle->linktype = DLT_BLUETOOTH_HCI_H4_WITH_PHDR;
225
226	handle->read_op = bt_read_linux;
227	handle->inject_op = bt_inject_linux;
228	handle->setfilter_op = install_bpf_program; /* no kernel filtering */
229	handle->setdirection_op = bt_setdirection_linux;
230	handle->set_datalink_op = NULL;	/* can't change data link type */
231	handle->getnonblock_op = pcap_getnonblock_fd;
232	handle->setnonblock_op = pcap_setnonblock_fd;
233	handle->stats_op = bt_stats_linux;
234	handlep->dev_id = dev_id;
235
236	/* Create HCI socket */
237	handle->fd = socket(AF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI);
238	if (handle->fd < 0) {
239		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
240		    errno, "Can't create raw socket");
241		return PCAP_ERROR;
242	}
243
244	handle->buffer = malloc(handle->bufsize);
245	if (!handle->buffer) {
246		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
247		    errno, "Can't allocate dump buffer");
248		goto close_fail;
249	}
250
251	opt = 1;
252	if (setsockopt(handle->fd, SOL_HCI, HCI_DATA_DIR, &opt, sizeof(opt)) < 0) {
253		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
254		    errno, "Can't enable data direction info");
255		goto close_fail;
256	}
257
258	opt = 1;
259	if (setsockopt(handle->fd, SOL_HCI, HCI_TIME_STAMP, &opt, sizeof(opt)) < 0) {
260		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
261		    errno, "Can't enable time stamp");
262		goto close_fail;
263	}
264
265	/* Setup filter, do not call hci function to avoid dependence on
266	 * external libs	*/
267	memset(&flt, 0, sizeof(flt));
268	memset((void *) &flt.type_mask, 0xff, sizeof(flt.type_mask));
269	memset((void *) &flt.event_mask, 0xff, sizeof(flt.event_mask));
270	if (setsockopt(handle->fd, SOL_HCI, HCI_FILTER, &flt, sizeof(flt)) < 0) {
271		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
272		    errno, "Can't set filter");
273		goto close_fail;
274	}
275
276
277	/* Bind socket to the HCI device */
278	addr.hci_family = AF_BLUETOOTH;
279	addr.hci_dev = handlep->dev_id;
280#ifdef HAVE_STRUCT_SOCKADDR_HCI_HCI_CHANNEL
281	addr.hci_channel = HCI_CHANNEL_RAW;
282#endif
283	if (bind(handle->fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
284		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
285		    errno, "Can't attach to device %d", handlep->dev_id);
286		goto close_fail;
287	}
288
289	if (handle->opt.rfmon) {
290		/*
291		 * Monitor mode doesn't apply to Bluetooth devices.
292		 */
293		err = PCAP_ERROR_RFMON_NOTSUP;
294		goto close_fail;
295	}
296
297	if (handle->opt.buffer_size != 0) {
298		/*
299		 * Set the socket buffer size to the specified value.
300		 */
301		if (setsockopt(handle->fd, SOL_SOCKET, SO_RCVBUF,
302		    &handle->opt.buffer_size,
303		    sizeof(handle->opt.buffer_size)) == -1) {
304			pcap_fmt_errmsg_for_errno(handle->errbuf,
305			    errno, PCAP_ERRBUF_SIZE, "SO_RCVBUF");
306			goto close_fail;
307		}
308	}
309
310	handle->selectable_fd = handle->fd;
311	return 0;
312
313close_fail:
314	pcap_cleanup_live_common(handle);
315	return err;
316}
317
318static int
319bt_read_linux(pcap_t *handle, int max_packets _U_, pcap_handler callback, u_char *user)
320{
321	struct cmsghdr *cmsg;
322	struct msghdr msg;
323	struct iovec  iv;
324	ssize_t ret;
325	struct pcap_pkthdr pkth;
326	pcap_bluetooth_h4_header* bthdr;
327	u_char *pktd;
328	int in = 0;
329
330	pktd = (u_char *)handle->buffer + BT_CTRL_SIZE;
331	bthdr = (pcap_bluetooth_h4_header*)(void *)pktd;
332	iv.iov_base = pktd + sizeof(pcap_bluetooth_h4_header);
333	iv.iov_len  = handle->snapshot;
334
335	memset(&msg, 0, sizeof(msg));
336	msg.msg_iov = &iv;
337	msg.msg_iovlen = 1;
338	msg.msg_control = handle->buffer;
339	msg.msg_controllen = BT_CTRL_SIZE;
340
341	/* ignore interrupt system call error */
342	do {
343		ret = recvmsg(handle->fd, &msg, 0);
344		if (handle->break_loop)
345		{
346			handle->break_loop = 0;
347			return -2;
348		}
349	} while ((ret == -1) && (errno == EINTR));
350
351	if (ret < 0) {
352		if (errno == EAGAIN || errno == EWOULDBLOCK) {
353			/* Nonblocking mode, no data */
354			return 0;
355		}
356		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
357		    errno, "Can't receive packet");
358		return -1;
359	}
360
361	pkth.caplen = (bpf_u_int32)ret;
362
363	/* get direction and timestamp*/
364	cmsg = CMSG_FIRSTHDR(&msg);
365	while (cmsg) {
366		switch (cmsg->cmsg_type) {
367			case HCI_CMSG_DIR:
368				memcpy(&in, CMSG_DATA(cmsg), sizeof in);
369				break;
370			case HCI_CMSG_TSTAMP:
371				memcpy(&pkth.ts, CMSG_DATA(cmsg),
372					sizeof pkth.ts);
373				break;
374		}
375		cmsg = CMSG_NXTHDR(&msg, cmsg);
376	}
377	switch (handle->direction) {
378
379	case PCAP_D_IN:
380		if (!in)
381			return 0;
382		break;
383
384	case PCAP_D_OUT:
385		if (in)
386			return 0;
387		break;
388
389	default:
390		break;
391	}
392
393	bthdr->direction = htonl(in != 0);
394	pkth.caplen+=sizeof(pcap_bluetooth_h4_header);
395	pkth.len = pkth.caplen;
396	if (handle->fcode.bf_insns == NULL ||
397	    pcap_filter(handle->fcode.bf_insns, pktd, pkth.len, pkth.caplen)) {
398		callback(user, &pkth, pktd);
399		return 1;
400	}
401	return 0;	/* didn't pass filter */
402}
403
404static int
405bt_inject_linux(pcap_t *handle, const void *buf _U_, int size _U_)
406{
407	snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
408	    "Packet injection is not supported on Bluetooth devices");
409	return (-1);
410}
411
412
413static int
414bt_stats_linux(pcap_t *handle, struct pcap_stat *stats)
415{
416	struct pcap_bt *handlep = handle->priv;
417	int ret;
418	struct hci_dev_info dev_info;
419	struct hci_dev_stats * s = &dev_info.stat;
420	dev_info.dev_id = handlep->dev_id;
421
422	/* ignore eintr */
423	do {
424		ret = ioctl(handle->fd, HCIGETDEVINFO, (void *)&dev_info);
425	} while ((ret == -1) && (errno == EINTR));
426
427	if (ret < 0) {
428		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
429		    errno, "Can't get stats via ioctl");
430		return (-1);
431
432	}
433
434	/* we receive both rx and tx frames, so comulate all stats */
435	stats->ps_recv = s->evt_rx + s->acl_rx + s->sco_rx + s->cmd_tx +
436		s->acl_tx +s->sco_tx;
437	stats->ps_drop = s->err_rx + s->err_tx;
438	stats->ps_ifdrop = 0;
439	return 0;
440}
441
442static int
443bt_setdirection_linux(pcap_t *p, pcap_direction_t d)
444{
445	/*
446	 * It's guaranteed, at this point, that d is a valid
447	 * direction value.
448	 */
449	p->direction = d;
450	return 0;
451}
452