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 <stdlib.h>
38#include <string.h>
39
40#include <bluetooth/bluetooth.h>
41#include <bluetooth/hci.h>
42#include <bluetooth/mgmt.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
52int
53bt_monitor_findalldevs(pcap_if_t **alldevsp, char *err_str)
54{
55    int         ret = 0;
56
57    if (pcap_add_if(alldevsp, INTERFACE_NAME, 0,
58               "Bluetooth Linux Monitor", err_str) < 0)
59    {
60        ret = -1;
61    }
62
63    return ret;
64}
65
66static int
67bt_monitor_read(pcap_t *handle, int max_packets _U_, pcap_handler callback, u_char *user)
68{
69    struct cmsghdr *cmsg;
70    struct msghdr msg;
71    struct iovec  iv[2];
72    ssize_t ret;
73    struct pcap_pkthdr pkth;
74    pcap_bluetooth_linux_monitor_header *bthdr;
75    struct mgmt_hdr hdr;
76
77    bthdr = (pcap_bluetooth_linux_monitor_header*) &handle->buffer[handle->offset];
78
79    iv[0].iov_base = &hdr;
80    iv[0].iov_len = MGMT_HDR_SIZE;
81    iv[1].iov_base = &handle->buffer[handle->offset + sizeof(pcap_bluetooth_linux_monitor_header)];
82    iv[1].iov_len = handle->snapshot;
83
84    memset(&pkth.ts, 0, sizeof(pkth.ts));
85    memset(&msg, 0, sizeof(msg));
86    msg.msg_iov = iv;
87    msg.msg_iovlen = 2;
88    msg.msg_control = handle->buffer;
89    msg.msg_controllen = handle->offset;
90
91    do {
92        ret = recvmsg(handle->fd, &msg, 0);
93        if (handle->break_loop)
94        {
95            handle->break_loop = 0;
96            return -2;
97        }
98    } while ((ret == -1) && (errno == EINTR));
99
100    if (ret < 0) {
101        snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
102            "Can't receive packet: %s", strerror(errno));
103        return -1;
104    }
105
106    pkth.caplen = ret - MGMT_HDR_SIZE + sizeof(pcap_bluetooth_linux_monitor_header);
107    pkth.len = pkth.caplen;
108
109    for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
110        if (cmsg->cmsg_level != SOL_SOCKET) continue;
111
112        if (cmsg->cmsg_type == SCM_TIMESTAMP) {
113            memcpy(&pkth.ts, CMSG_DATA(cmsg), sizeof(pkth.ts));
114        }
115    }
116
117    bthdr->adapter_id = htons(hdr.index);
118    bthdr->opcode = htons(hdr.opcode);
119
120    if (handle->fcode.bf_insns == NULL ||
121        bpf_filter(handle->fcode.bf_insns, &handle->buffer[handle->offset],
122          pkth.len, pkth.caplen)) {
123        callback(user, &pkth, &handle->buffer[handle->offset]);
124        return 1;
125    }
126    return 0;   /* didn't pass filter */
127}
128
129static int
130bt_monitor_inject(pcap_t *handle, const void *buf _U_, size_t size _U_)
131{
132    snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "inject not supported yet");
133    return -1;
134}
135
136static int
137bt_monitor_setdirection(pcap_t *p, pcap_direction_t d)
138{
139    p->direction = d;
140    return 0;
141}
142
143static int
144bt_monitor_stats(pcap_t *handle _U_, struct pcap_stat *stats)
145{
146    stats->ps_recv = 0;
147    stats->ps_drop = 0;
148    stats->ps_ifdrop = 0;
149
150    return 0;
151}
152
153static int
154bt_monitor_activate(pcap_t* handle)
155{
156    struct sockaddr_hci addr;
157    int err = PCAP_ERROR;
158    int opt;
159
160    if (handle->opt.rfmon) {
161        /* monitor mode doesn't apply here */
162        return PCAP_ERROR_RFMON_NOTSUP;
163    }
164
165    handle->bufsize = handle->snapshot + BT_CONTROL_SIZE + sizeof(pcap_bluetooth_linux_monitor_header);
166    handle->offset = BT_CONTROL_SIZE;
167    handle->linktype = DLT_BLUETOOTH_LINUX_MONITOR;
168
169    handle->read_op = bt_monitor_read;
170    handle->inject_op = bt_monitor_inject;
171    handle->setfilter_op = install_bpf_program; /* no kernel filtering */
172    handle->setdirection_op = bt_monitor_setdirection;
173    handle->set_datalink_op = NULL; /* can't change data link type */
174    handle->getnonblock_op = pcap_getnonblock_fd;
175    handle->setnonblock_op = pcap_setnonblock_fd;
176    handle->stats_op = bt_monitor_stats;
177
178    handle->fd = socket(AF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI);
179    if (handle->fd < 0) {
180        snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
181            "Can't create raw socket: %s", strerror(errno));
182        return PCAP_ERROR;
183    }
184
185    handle->buffer = malloc(handle->bufsize);
186    if (!handle->buffer) {
187        snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't allocate dump buffer: %s",
188            pcap_strerror(errno));
189        goto close_fail;
190    }
191
192    /* Bind socket to the HCI device */
193    addr.hci_family = AF_BLUETOOTH;
194    addr.hci_dev = HCI_DEV_NONE;
195    addr.hci_channel = HCI_CHANNEL_MONITOR;
196
197    if (bind(handle->fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
198        snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
199            "Can't attach to interface: %s", strerror(errno));
200        goto close_fail;
201    }
202
203    opt = 1;
204    if (setsockopt(handle->fd, SOL_SOCKET, SO_TIMESTAMP, &opt, sizeof(opt)) < 0) {
205        snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
206            "Can't enable time stamp: %s", strerror(errno));
207        goto close_fail;
208    }
209
210    handle->selectable_fd = handle->fd;
211
212    return 0;
213
214close_fail:
215    pcap_cleanup_live_common(handle);
216    return err;
217}
218
219pcap_t *
220bt_monitor_create(const char *device, char *ebuf, int *is_ours)
221{
222    pcap_t      *p;
223    const char  *cp;
224
225    cp = strrchr(device, '/');
226    if (cp == NULL)
227        cp = device;
228
229    if (strcmp(cp, INTERFACE_NAME) != 0) {
230        *is_ours = 0;
231        return NULL;
232    }
233
234    *is_ours = 1;
235    p = pcap_create_common(device, ebuf, 0);
236    if (p == NULL)
237        return NULL;
238
239    p->activate_op = bt_monitor_activate;
240
241    return p;
242}
243