xref: /freebsd/contrib/libpcap/pcap-bt-monitor-linux.c (revision fa50a3552d1e759e1bb65e54cb0b7e863bcf54d5)
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  */
56 struct hci_mon_hdr {
57     uint16_t opcode;
58     uint16_t index;
59     uint16_t len;
60 } __attribute__((packed));
61 
62 int
63 bt_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 
85 static int
86 bt_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 
149 static int
150 bt_monitor_inject(pcap_t *handle, const void *buf _U_, size_t size _U_)
151 {
152     pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "inject not supported yet");
153     return -1;
154 }
155 
156 static int
157 bt_monitor_setdirection(pcap_t *p, pcap_direction_t d)
158 {
159     p->direction = d;
160     return 0;
161 }
162 
163 static int
164 bt_monitor_stats(pcap_t *handle _U_, struct pcap_stat *stats)
165 {
166     stats->ps_recv = 0;
167     stats->ps_drop = 0;
168     stats->ps_ifdrop = 0;
169 
170     return 0;
171 }
172 
173 static int
174 bt_monitor_activate(pcap_t* handle)
175 {
176     struct sockaddr_hci addr;
177     int err = PCAP_ERROR;
178     int opt;
179 
180     if (handle->opt.rfmon) {
181         /* monitor mode doesn't apply here */
182         return PCAP_ERROR_RFMON_NOTSUP;
183     }
184 
185     /*
186      * Turn a negative snapshot value (invalid), a snapshot value of
187      * 0 (unspecified), or a value bigger than the normal maximum
188      * value, into the maximum allowed value.
189      *
190      * If some application really *needs* a bigger snapshot
191      * length, we should just increase MAXIMUM_SNAPLEN.
192      */
193     if (handle->snapshot <= 0 || handle->snapshot > MAXIMUM_SNAPLEN)
194         handle->snapshot = MAXIMUM_SNAPLEN;
195 
196     handle->bufsize = BT_CONTROL_SIZE + sizeof(pcap_bluetooth_linux_monitor_header) + handle->snapshot;
197     handle->linktype = DLT_BLUETOOTH_LINUX_MONITOR;
198 
199     handle->read_op = bt_monitor_read;
200     handle->inject_op = bt_monitor_inject;
201     handle->setfilter_op = install_bpf_program; /* no kernel filtering */
202     handle->setdirection_op = bt_monitor_setdirection;
203     handle->set_datalink_op = NULL; /* can't change data link type */
204     handle->getnonblock_op = pcap_getnonblock_fd;
205     handle->setnonblock_op = pcap_setnonblock_fd;
206     handle->stats_op = bt_monitor_stats;
207 
208     handle->fd = socket(AF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI);
209     if (handle->fd < 0) {
210         pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
211             errno, "Can't create raw socket");
212         return PCAP_ERROR;
213     }
214 
215     handle->buffer = malloc(handle->bufsize);
216     if (!handle->buffer) {
217         pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
218             errno, "Can't allocate dump buffer");
219         goto close_fail;
220     }
221 
222     /* Bind socket to the HCI device */
223     addr.hci_family = AF_BLUETOOTH;
224     addr.hci_dev = HCI_DEV_NONE;
225     addr.hci_channel = HCI_CHANNEL_MONITOR;
226 
227     if (bind(handle->fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
228         pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
229             errno, "Can't attach to interface");
230         goto close_fail;
231     }
232 
233     opt = 1;
234     if (setsockopt(handle->fd, SOL_SOCKET, SO_TIMESTAMP, &opt, sizeof(opt)) < 0) {
235         pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
236             errno, "Can't enable time stamp");
237         goto close_fail;
238     }
239 
240     handle->selectable_fd = handle->fd;
241 
242     return 0;
243 
244 close_fail:
245     pcap_cleanup_live_common(handle);
246     return err;
247 }
248 
249 pcap_t *
250 bt_monitor_create(const char *device, char *ebuf, int *is_ours)
251 {
252     pcap_t      *p;
253     const char  *cp;
254 
255     cp = strrchr(device, '/');
256     if (cp == NULL)
257         cp = device;
258 
259     if (strcmp(cp, INTERFACE_NAME) != 0) {
260         *is_ours = 0;
261         return NULL;
262     }
263 
264     *is_ours = 1;
265     p = pcap_create_common(ebuf, 0);
266     if (p == NULL)
267         return NULL;
268 
269     p->activate_op = bt_monitor_activate;
270 
271     return p;
272 }
273