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 #include <config.h>
33
34 #include <errno.h>
35 #include <stdint.h>
36 #include <stdlib.h>
37 #include <string.h>
38
39 #include <bluetooth/bluetooth.h>
40 #include <bluetooth/hci.h>
41
42 #include "pcap/bluetooth.h"
43 #include "pcap-int.h"
44 #include "diag-control.h"
45
46 #include "pcap-bt-monitor-linux.h"
47
48 #define BT_CONTROL_SIZE 32
49 #define INTERFACE_NAME "bluetooth-monitor"
50
51 /*
52 * Private data.
53 * Currently contains nothing.
54 */
55 struct pcap_bt_monitor {
56 int dummy;
57 };
58
59 /*
60 * Fields and alignment must match the declaration in the Linux kernel 3.4+.
61 * See struct hci_mon_hdr in include/net/bluetooth/hci_mon.h.
62 */
63 struct hci_mon_hdr {
64 uint16_t opcode;
65 uint16_t index;
66 uint16_t len;
67 } __attribute__((packed));
68
69 int
bt_monitor_findalldevs(pcap_if_list_t * devlistp,char * err_str)70 bt_monitor_findalldevs(pcap_if_list_t *devlistp, char *err_str)
71 {
72 int ret = 0;
73
74 /*
75 * Bluetooth is a wireless technology.
76 *
77 * This is a device to monitor all Bluetooth interfaces, so
78 * there's no notion of "connected" or "disconnected", any
79 * more than there's a notion of "connected" or "disconnected"
80 * for the "any" device.
81 */
82 if (pcapint_add_dev(devlistp, INTERFACE_NAME,
83 PCAP_IF_WIRELESS|PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE,
84 "Bluetooth Linux Monitor", err_str) == NULL)
85 {
86 ret = PCAP_ERROR;
87 }
88
89 return ret;
90 }
91
92 static int
bt_monitor_read(pcap_t * handle,int max_packets _U_,pcap_handler callback,u_char * user)93 bt_monitor_read(pcap_t *handle, int max_packets _U_, pcap_handler callback, u_char *user)
94 {
95 struct cmsghdr *cmsg;
96 struct msghdr msg;
97 struct iovec iv[2];
98 ssize_t ret;
99 struct pcap_pkthdr pkth;
100 pcap_bluetooth_linux_monitor_header *bthdr;
101 u_char *pktd;
102 struct hci_mon_hdr hdr;
103
104 pktd = (u_char *)handle->buffer + BT_CONTROL_SIZE;
105 bthdr = (pcap_bluetooth_linux_monitor_header*)(void *)pktd;
106
107 iv[0].iov_base = &hdr;
108 iv[0].iov_len = sizeof(hdr);
109 iv[1].iov_base = pktd + sizeof(pcap_bluetooth_linux_monitor_header);
110 iv[1].iov_len = handle->snapshot;
111
112 memset(&pkth.ts, 0, sizeof(pkth.ts));
113 memset(&msg, 0, sizeof(msg));
114 msg.msg_iov = iv;
115 msg.msg_iovlen = 2;
116 msg.msg_control = handle->buffer;
117 msg.msg_controllen = BT_CONTROL_SIZE;
118
119 do {
120 if (handle->break_loop)
121 {
122 handle->break_loop = 0;
123 return PCAP_ERROR_BREAK;
124 }
125 ret = recvmsg(handle->fd, &msg, 0);
126 } while ((ret == -1) && (errno == EINTR));
127
128 if (ret < 0) {
129 if (errno == EAGAIN || errno == EWOULDBLOCK) {
130 /* Nonblocking mode, no data */
131 return 0;
132 }
133 pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
134 errno, "Can't receive packet");
135 return PCAP_ERROR;
136 }
137
138 pkth.caplen = (bpf_u_int32)(ret - sizeof(hdr) + sizeof(pcap_bluetooth_linux_monitor_header));
139 pkth.len = pkth.caplen;
140
141 // for musl libc CMSG_NXTHDR()
142 DIAG_OFF_SIGN_COMPARE
143 for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
144 DIAG_ON_SIGN_COMPARE
145 if (cmsg->cmsg_level != SOL_SOCKET) continue;
146
147 if (cmsg->cmsg_type == SCM_TIMESTAMP) {
148 memcpy(&pkth.ts, CMSG_DATA(cmsg), sizeof(pkth.ts));
149 }
150 }
151
152 bthdr->adapter_id = htons(hdr.index);
153 bthdr->opcode = htons(hdr.opcode);
154
155 if (handle->fcode.bf_insns == NULL ||
156 pcapint_filter(handle->fcode.bf_insns, pktd, pkth.len, pkth.caplen)) {
157 callback(user, &pkth, pktd);
158 return 1;
159 }
160 return 0; /* didn't pass filter */
161 }
162
163 static int
bt_monitor_inject(pcap_t * handle,const void * buf _U_,int size _U_)164 bt_monitor_inject(pcap_t *handle, const void *buf _U_, int size _U_)
165 {
166 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
167 "Packet injection is not supported yet on Bluetooth monitor devices");
168 return PCAP_ERROR;
169 }
170
171 static int
bt_monitor_stats(pcap_t * handle _U_,struct pcap_stat * stats)172 bt_monitor_stats(pcap_t *handle _U_, struct pcap_stat *stats)
173 {
174 stats->ps_recv = 0;
175 stats->ps_drop = 0;
176 stats->ps_ifdrop = 0;
177
178 return 0;
179 }
180
181 static int
bt_monitor_activate(pcap_t * handle)182 bt_monitor_activate(pcap_t* handle)
183 {
184 struct sockaddr_hci addr;
185 int err = PCAP_ERROR;
186 int opt;
187
188 if (handle->opt.rfmon) {
189 /* monitor mode doesn't apply here */
190 return PCAP_ERROR_RFMON_NOTSUP;
191 }
192
193 /*
194 * Turn a negative snapshot value (invalid), a snapshot value of
195 * 0 (unspecified), or a value bigger than the normal maximum
196 * value, into the maximum allowed value.
197 *
198 * If some application really *needs* a bigger snapshot
199 * length, we should just increase MAXIMUM_SNAPLEN.
200 */
201 if (handle->snapshot <= 0 || handle->snapshot > MAXIMUM_SNAPLEN)
202 handle->snapshot = MAXIMUM_SNAPLEN;
203
204 handle->bufsize = BT_CONTROL_SIZE + sizeof(pcap_bluetooth_linux_monitor_header) + handle->snapshot;
205 handle->linktype = DLT_BLUETOOTH_LINUX_MONITOR;
206
207 handle->read_op = bt_monitor_read;
208 handle->inject_op = bt_monitor_inject;
209 handle->setfilter_op = pcapint_install_bpf_program; /* no kernel filtering */
210 handle->setdirection_op = NULL; /* Not implemented */
211 handle->set_datalink_op = NULL; /* can't change data link type */
212 handle->getnonblock_op = pcapint_getnonblock_fd;
213 handle->setnonblock_op = pcapint_setnonblock_fd;
214 handle->stats_op = bt_monitor_stats;
215
216 handle->fd = socket(AF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI);
217 if (handle->fd < 0) {
218 pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
219 errno, "Can't create raw socket");
220 return PCAP_ERROR;
221 }
222
223 handle->buffer = malloc(handle->bufsize);
224 if (!handle->buffer) {
225 pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
226 errno, "Can't allocate dump buffer");
227 goto close_fail;
228 }
229
230 /* Bind socket to the HCI device */
231 addr.hci_family = AF_BLUETOOTH;
232 addr.hci_dev = HCI_DEV_NONE;
233 addr.hci_channel = HCI_CHANNEL_MONITOR;
234
235 if (bind(handle->fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
236 pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
237 errno, "Can't attach to interface");
238 goto close_fail;
239 }
240
241 opt = 1;
242 if (setsockopt(handle->fd, SOL_SOCKET, SO_TIMESTAMP, &opt, sizeof(opt)) < 0) {
243 pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
244 errno, "Can't enable time stamp");
245 goto close_fail;
246 }
247
248 handle->selectable_fd = handle->fd;
249
250 return 0;
251
252 close_fail:
253 pcapint_cleanup_live_common(handle);
254 return err;
255 }
256
257 pcap_t *
bt_monitor_create(const char * device,char * ebuf,int * is_ours)258 bt_monitor_create(const char *device, char *ebuf, int *is_ours)
259 {
260 pcap_t *p;
261 const char *cp;
262
263 cp = strrchr(device, '/');
264 if (cp == NULL)
265 cp = device;
266
267 if (strcmp(cp, INTERFACE_NAME) != 0) {
268 *is_ours = 0;
269 return NULL;
270 }
271
272 *is_ours = 1;
273 p = PCAP_CREATE_COMMON(ebuf, struct pcap_bt_monitor);
274 if (p == NULL)
275 return NULL;
276
277 p->activate_op = bt_monitor_activate;
278
279 return p;
280 }
281