pcap-bt-monitor-linux.c revision 356341 
1/*
2 * Copyright (c) 2014 Michal Labedzki for Tieto Corporation
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 */
31
32#ifdef HAVE_CONFIG_H
33#include <config.h>
34#endif
35
36#include <errno.h>
37#include <stdint.h>
38#include <stdlib.h>
39#include <string.h>
40
41#include <bluetooth/bluetooth.h>
42#include <bluetooth/hci.h>
43
44#include "pcap/bluetooth.h"
45#include "pcap-int.h"
46
47#include "pcap-bt-monitor-linux.h"
48
49#define BT_CONTROL_SIZE 32
50#define INTERFACE_NAME "bluetooth-monitor"
51
52/*
53 * Fields and alignment must match the declaration in the Linux kernel 3.4+.
54 * See struct hci_mon_hdr in include/net/bluetooth/hci_mon.h.
55 */
56struct hci_mon_hdr {
57    uint16_t opcode;
58    uint16_t index;
59    uint16_t len;
60} __attribute__((packed));
61
62int
63bt_monitor_findalldevs(pcap_if_list_t *devlistp, char *err_str)
64{
65    int         ret = 0;
66
67    /*
68     * Bluetooth is a wireless technology.
69     *
70     * This is a device to monitor all Bluetooth interfaces, so
71     * there's no notion of "connected" or "disconnected", any
72     * more than there's a notion of "connected" or "disconnected"
73     * for the "any" device.
74     */
75    if (add_dev(devlistp, INTERFACE_NAME,
76                PCAP_IF_WIRELESS|PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE,
77                "Bluetooth Linux Monitor", err_str) == NULL)
78    {
79        ret = -1;
80    }
81
82    return ret;
83}
84
85static int
86bt_monitor_read(pcap_t *handle, int max_packets _U_, pcap_handler callback, u_char *user)
87{
88    struct cmsghdr *cmsg;
89    struct msghdr msg;
90    struct iovec  iv[2];
91    ssize_t ret;
92    struct pcap_pkthdr pkth;
93    pcap_bluetooth_linux_monitor_header *bthdr;
94    u_char *pktd;
95    struct hci_mon_hdr hdr;
96
97    pktd = (u_char *)handle->buffer + BT_CONTROL_SIZE;
98    bthdr = (pcap_bluetooth_linux_monitor_header*)(void *)pktd;
99
100    iv[0].iov_base = &hdr;
101    iv[0].iov_len = sizeof(hdr);
102    iv[1].iov_base = pktd + sizeof(pcap_bluetooth_linux_monitor_header);
103    iv[1].iov_len = handle->snapshot;
104
105    memset(&pkth.ts, 0, sizeof(pkth.ts));
106    memset(&msg, 0, sizeof(msg));
107    msg.msg_iov = iv;
108    msg.msg_iovlen = 2;
109    msg.msg_control = handle->buffer;
110    msg.msg_controllen = BT_CONTROL_SIZE;
111
112    do {
113        ret = recvmsg(handle->fd, &msg, 0);
114        if (handle->break_loop)
115        {
116            handle->break_loop = 0;
117            return -2;
118        }
119    } while ((ret == -1) && (errno == EINTR));
120
121    if (ret < 0) {
122        pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
123            errno, "Can't receive packet");
124        return -1;
125    }
126
127    pkth.caplen = ret - sizeof(hdr) + sizeof(pcap_bluetooth_linux_monitor_header);
128    pkth.len = pkth.caplen;
129
130    for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
131        if (cmsg->cmsg_level != SOL_SOCKET) continue;
132
133        if (cmsg->cmsg_type == SCM_TIMESTAMP) {
134            memcpy(&pkth.ts, CMSG_DATA(cmsg), sizeof(pkth.ts));
135        }
136    }
137
138    bthdr->adapter_id = htons(hdr.index);
139    bthdr->opcode = htons(hdr.opcode);
140
141    if (handle->fcode.bf_insns == NULL ||
142        bpf_filter(handle->fcode.bf_insns, pktd, pkth.len, pkth.caplen)) {
143        callback(user, &pkth, pktd);
144        return 1;
145    }
146    return 0;   /* didn't pass filter */
147}
148
149static int
150bt_monitor_inject(pcap_t *handle, const void *buf _U_, size_t size _U_)
151{
152    pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
153        "Packet injection is not supported yet on Bluetooth monitor devices");
154    return -1;
155}
156
157static int
158bt_monitor_setdirection(pcap_t *p, pcap_direction_t d)
159{
160    p->direction = d;
161    return 0;
162}
163
164static int
165bt_monitor_stats(pcap_t *handle _U_, struct pcap_stat *stats)
166{
167    stats->ps_recv = 0;
168    stats->ps_drop = 0;
169    stats->ps_ifdrop = 0;
170
171    return 0;
172}
173
174static int
175bt_monitor_activate(pcap_t* handle)
176{
177    struct sockaddr_hci addr;
178    int err = PCAP_ERROR;
179    int opt;
180
181    if (handle->opt.rfmon) {
182        /* monitor mode doesn't apply here */
183        return PCAP_ERROR_RFMON_NOTSUP;
184    }
185
186    /*
187     * Turn a negative snapshot value (invalid), a snapshot value of
188     * 0 (unspecified), or a value bigger than the normal maximum
189     * value, into the maximum allowed value.
190     *
191     * If some application really *needs* a bigger snapshot
192     * length, we should just increase MAXIMUM_SNAPLEN.
193     */
194    if (handle->snapshot <= 0 || handle->snapshot > MAXIMUM_SNAPLEN)
195        handle->snapshot = MAXIMUM_SNAPLEN;
196
197    handle->bufsize = BT_CONTROL_SIZE + sizeof(pcap_bluetooth_linux_monitor_header) + handle->snapshot;
198    handle->linktype = DLT_BLUETOOTH_LINUX_MONITOR;
199
200    handle->read_op = bt_monitor_read;
201    handle->inject_op = bt_monitor_inject;
202    handle->setfilter_op = install_bpf_program; /* no kernel filtering */
203    handle->setdirection_op = bt_monitor_setdirection;
204    handle->set_datalink_op = NULL; /* can't change data link type */
205    handle->getnonblock_op = pcap_getnonblock_fd;
206    handle->setnonblock_op = pcap_setnonblock_fd;
207    handle->stats_op = bt_monitor_stats;
208
209    handle->fd = socket(AF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI);
210    if (handle->fd < 0) {
211        pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
212            errno, "Can't create raw socket");
213        return PCAP_ERROR;
214    }
215
216    handle->buffer = malloc(handle->bufsize);
217    if (!handle->buffer) {
218        pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
219            errno, "Can't allocate dump buffer");
220        goto close_fail;
221    }
222
223    /* Bind socket to the HCI device */
224    addr.hci_family = AF_BLUETOOTH;
225    addr.hci_dev = HCI_DEV_NONE;
226    addr.hci_channel = HCI_CHANNEL_MONITOR;
227
228    if (bind(handle->fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
229        pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
230            errno, "Can't attach to interface");
231        goto close_fail;
232    }
233
234    opt = 1;
235    if (setsockopt(handle->fd, SOL_SOCKET, SO_TIMESTAMP, &opt, sizeof(opt)) < 0) {
236        pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
237            errno, "Can't enable time stamp");
238        goto close_fail;
239    }
240
241    handle->selectable_fd = handle->fd;
242
243    return 0;
244
245close_fail:
246    pcap_cleanup_live_common(handle);
247    return err;
248}
249
250pcap_t *
251bt_monitor_create(const char *device, char *ebuf, int *is_ours)
252{
253    pcap_t      *p;
254    const char  *cp;
255
256    cp = strrchr(device, '/');
257    if (cp == NULL)
258        cp = device;
259
260    if (strcmp(cp, INTERFACE_NAME) != 0) {
261        *is_ours = 0;
262        return NULL;
263    }
264
265    *is_ours = 1;
266    p = pcap_create_common(ebuf, 0);
267    if (p == NULL)
268        return NULL;
269
270    p->activate_op = bt_monitor_activate;
271
272    return p;
273}
274