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 * Private data.
54 * Currently contains nothing.
55 */
56struct pcap_bt_monitor {
57	int	dummy;
58};
59
60/*
61 * Fields and alignment must match the declaration in the Linux kernel 3.4+.
62 * See struct hci_mon_hdr in include/net/bluetooth/hci_mon.h.
63 */
64struct hci_mon_hdr {
65    uint16_t opcode;
66    uint16_t index;
67    uint16_t len;
68} __attribute__((packed));
69
70int
71bt_monitor_findalldevs(pcap_if_list_t *devlistp, char *err_str)
72{
73    int         ret = 0;
74
75    /*
76     * Bluetooth is a wireless technology.
77     *
78     * This is a device to monitor all Bluetooth interfaces, so
79     * there's no notion of "connected" or "disconnected", any
80     * more than there's a notion of "connected" or "disconnected"
81     * for the "any" device.
82     */
83    if (add_dev(devlistp, INTERFACE_NAME,
84                PCAP_IF_WIRELESS|PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE,
85                "Bluetooth Linux Monitor", err_str) == NULL)
86    {
87        ret = -1;
88    }
89
90    return ret;
91}
92
93static int
94bt_monitor_read(pcap_t *handle, int max_packets _U_, pcap_handler callback, u_char *user)
95{
96    struct cmsghdr *cmsg;
97    struct msghdr msg;
98    struct iovec  iv[2];
99    ssize_t ret;
100    struct pcap_pkthdr pkth;
101    pcap_bluetooth_linux_monitor_header *bthdr;
102    u_char *pktd;
103    struct hci_mon_hdr hdr;
104
105    pktd = (u_char *)handle->buffer + BT_CONTROL_SIZE;
106    bthdr = (pcap_bluetooth_linux_monitor_header*)(void *)pktd;
107
108    iv[0].iov_base = &hdr;
109    iv[0].iov_len = sizeof(hdr);
110    iv[1].iov_base = pktd + sizeof(pcap_bluetooth_linux_monitor_header);
111    iv[1].iov_len = handle->snapshot;
112
113    memset(&pkth.ts, 0, sizeof(pkth.ts));
114    memset(&msg, 0, sizeof(msg));
115    msg.msg_iov = iv;
116    msg.msg_iovlen = 2;
117    msg.msg_control = handle->buffer;
118    msg.msg_controllen = BT_CONTROL_SIZE;
119
120    do {
121        ret = recvmsg(handle->fd, &msg, 0);
122        if (handle->break_loop)
123        {
124            handle->break_loop = 0;
125            return -2;
126        }
127    } while ((ret == -1) && (errno == EINTR));
128
129    if (ret < 0) {
130        if (errno == EAGAIN || errno == EWOULDBLOCK) {
131            /* Nonblocking mode, no data */
132            return 0;
133        }
134        pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
135            errno, "Can't receive packet");
136        return -1;
137    }
138
139    pkth.caplen = (bpf_u_int32)(ret - sizeof(hdr) + sizeof(pcap_bluetooth_linux_monitor_header));
140    pkth.len = pkth.caplen;
141
142    for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
143        if (cmsg->cmsg_level != SOL_SOCKET) continue;
144
145        if (cmsg->cmsg_type == SCM_TIMESTAMP) {
146            memcpy(&pkth.ts, CMSG_DATA(cmsg), sizeof(pkth.ts));
147        }
148    }
149
150    bthdr->adapter_id = htons(hdr.index);
151    bthdr->opcode = htons(hdr.opcode);
152
153    if (handle->fcode.bf_insns == NULL ||
154        pcap_filter(handle->fcode.bf_insns, pktd, pkth.len, pkth.caplen)) {
155        callback(user, &pkth, pktd);
156        return 1;
157    }
158    return 0;   /* didn't pass filter */
159}
160
161static int
162bt_monitor_inject(pcap_t *handle, const void *buf _U_, int size _U_)
163{
164    snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
165        "Packet injection is not supported yet on Bluetooth monitor devices");
166    return -1;
167}
168
169static int
170bt_monitor_stats(pcap_t *handle _U_, struct pcap_stat *stats)
171{
172    stats->ps_recv = 0;
173    stats->ps_drop = 0;
174    stats->ps_ifdrop = 0;
175
176    return 0;
177}
178
179static int
180bt_monitor_activate(pcap_t* handle)
181{
182    struct sockaddr_hci addr;
183    int err = PCAP_ERROR;
184    int opt;
185
186    if (handle->opt.rfmon) {
187        /* monitor mode doesn't apply here */
188        return PCAP_ERROR_RFMON_NOTSUP;
189    }
190
191    /*
192     * Turn a negative snapshot value (invalid), a snapshot value of
193     * 0 (unspecified), or a value bigger than the normal maximum
194     * value, into the maximum allowed value.
195     *
196     * If some application really *needs* a bigger snapshot
197     * length, we should just increase MAXIMUM_SNAPLEN.
198     */
199    if (handle->snapshot <= 0 || handle->snapshot > MAXIMUM_SNAPLEN)
200        handle->snapshot = MAXIMUM_SNAPLEN;
201
202    handle->bufsize = BT_CONTROL_SIZE + sizeof(pcap_bluetooth_linux_monitor_header) + handle->snapshot;
203    handle->linktype = DLT_BLUETOOTH_LINUX_MONITOR;
204
205    handle->read_op = bt_monitor_read;
206    handle->inject_op = bt_monitor_inject;
207    handle->setfilter_op = install_bpf_program; /* no kernel filtering */
208    handle->setdirection_op = NULL; /* Not implemented */
209    handle->set_datalink_op = NULL; /* can't change data link type */
210    handle->getnonblock_op = pcap_getnonblock_fd;
211    handle->setnonblock_op = pcap_setnonblock_fd;
212    handle->stats_op = bt_monitor_stats;
213
214    handle->fd = socket(AF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI);
215    if (handle->fd < 0) {
216        pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
217            errno, "Can't create raw socket");
218        return PCAP_ERROR;
219    }
220
221    handle->buffer = malloc(handle->bufsize);
222    if (!handle->buffer) {
223        pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
224            errno, "Can't allocate dump buffer");
225        goto close_fail;
226    }
227
228    /* Bind socket to the HCI device */
229    addr.hci_family = AF_BLUETOOTH;
230    addr.hci_dev = HCI_DEV_NONE;
231    addr.hci_channel = HCI_CHANNEL_MONITOR;
232
233    if (bind(handle->fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
234        pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
235            errno, "Can't attach to interface");
236        goto close_fail;
237    }
238
239    opt = 1;
240    if (setsockopt(handle->fd, SOL_SOCKET, SO_TIMESTAMP, &opt, sizeof(opt)) < 0) {
241        pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
242            errno, "Can't enable time stamp");
243        goto close_fail;
244    }
245
246    handle->selectable_fd = handle->fd;
247
248    return 0;
249
250close_fail:
251    pcap_cleanup_live_common(handle);
252    return err;
253}
254
255pcap_t *
256bt_monitor_create(const char *device, char *ebuf, int *is_ours)
257{
258    pcap_t      *p;
259    const char  *cp;
260
261    cp = strrchr(device, '/');
262    if (cp == NULL)
263        cp = device;
264
265    if (strcmp(cp, INTERFACE_NAME) != 0) {
266        *is_ours = 0;
267        return NULL;
268    }
269
270    *is_ours = 1;
271    p = PCAP_CREATE_COMMON(ebuf, struct pcap_bt_monitor);
272    if (p == NULL)
273        return NULL;
274
275    p->activate_op = bt_monitor_activate;
276
277    return p;
278}
279