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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
bt_monitor_findalldevs(pcap_if_t ** alldevsp,char * err_str)63 bt_monitor_findalldevs(pcap_if_t **alldevsp, char *err_str)
64 {
65     int         ret = 0;
66 
67     if (pcap_add_if(alldevsp, INTERFACE_NAME, 0,
68                "Bluetooth Linux Monitor", err_str) < 0)
69     {
70         ret = -1;
71     }
72 
73     return ret;
74 }
75 
76 static int
bt_monitor_read(pcap_t * handle,int max_packets _U_,pcap_handler callback,u_char * user)77 bt_monitor_read(pcap_t *handle, int max_packets _U_, pcap_handler callback, u_char *user)
78 {
79     struct cmsghdr *cmsg;
80     struct msghdr msg;
81     struct iovec  iv[2];
82     ssize_t ret;
83     struct pcap_pkthdr pkth;
84     pcap_bluetooth_linux_monitor_header *bthdr;
85     u_char *pktd;
86     struct hci_mon_hdr hdr;
87 
88     pktd = (u_char *)handle->buffer + BT_CONTROL_SIZE;
89     bthdr = (pcap_bluetooth_linux_monitor_header*)(void *)pktd;
90 
91     iv[0].iov_base = &hdr;
92     iv[0].iov_len = sizeof(hdr);
93     iv[1].iov_base = pktd + sizeof(pcap_bluetooth_linux_monitor_header);
94     iv[1].iov_len = handle->snapshot;
95 
96     memset(&pkth.ts, 0, sizeof(pkth.ts));
97     memset(&msg, 0, sizeof(msg));
98     msg.msg_iov = iv;
99     msg.msg_iovlen = 2;
100     msg.msg_control = handle->buffer;
101     msg.msg_controllen = BT_CONTROL_SIZE;
102 
103     do {
104         ret = recvmsg(handle->fd, &msg, 0);
105         if (handle->break_loop)
106         {
107             handle->break_loop = 0;
108             return -2;
109         }
110     } while ((ret == -1) && (errno == EINTR));
111 
112     if (ret < 0) {
113         pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
114             "Can't receive packet: %s", strerror(errno));
115         return -1;
116     }
117 
118     pkth.caplen = ret - sizeof(hdr) + sizeof(pcap_bluetooth_linux_monitor_header);
119     pkth.len = pkth.caplen;
120 
121     for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
122         if (cmsg->cmsg_level != SOL_SOCKET) continue;
123 
124         if (cmsg->cmsg_type == SCM_TIMESTAMP) {
125             memcpy(&pkth.ts, CMSG_DATA(cmsg), sizeof(pkth.ts));
126         }
127     }
128 
129     bthdr->adapter_id = htons(hdr.index);
130     bthdr->opcode = htons(hdr.opcode);
131 
132     if (handle->fcode.bf_insns == NULL ||
133         bpf_filter(handle->fcode.bf_insns, pktd, pkth.len, pkth.caplen)) {
134         callback(user, &pkth, pktd);
135         return 1;
136     }
137     return 0;   /* didn't pass filter */
138 }
139 
140 static int
bt_monitor_inject(pcap_t * handle,const void * buf _U_,size_t size _U_)141 bt_monitor_inject(pcap_t *handle, const void *buf _U_, size_t size _U_)
142 {
143     pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "inject not supported yet");
144     return -1;
145 }
146 
147 static int
bt_monitor_setdirection(pcap_t * p,pcap_direction_t d)148 bt_monitor_setdirection(pcap_t *p, pcap_direction_t d)
149 {
150     p->direction = d;
151     return 0;
152 }
153 
154 static int
bt_monitor_stats(pcap_t * handle _U_,struct pcap_stat * stats)155 bt_monitor_stats(pcap_t *handle _U_, struct pcap_stat *stats)
156 {
157     stats->ps_recv = 0;
158     stats->ps_drop = 0;
159     stats->ps_ifdrop = 0;
160 
161     return 0;
162 }
163 
164 static int
bt_monitor_activate(pcap_t * handle)165 bt_monitor_activate(pcap_t* handle)
166 {
167     struct sockaddr_hci addr;
168     int err = PCAP_ERROR;
169     int opt;
170 
171     if (handle->opt.rfmon) {
172         /* monitor mode doesn't apply here */
173         return PCAP_ERROR_RFMON_NOTSUP;
174     }
175 
176     handle->bufsize = BT_CONTROL_SIZE + sizeof(pcap_bluetooth_linux_monitor_header) + handle->snapshot;
177     handle->linktype = DLT_BLUETOOTH_LINUX_MONITOR;
178 
179     handle->read_op = bt_monitor_read;
180     handle->inject_op = bt_monitor_inject;
181     handle->setfilter_op = install_bpf_program; /* no kernel filtering */
182     handle->setdirection_op = bt_monitor_setdirection;
183     handle->set_datalink_op = NULL; /* can't change data link type */
184     handle->getnonblock_op = pcap_getnonblock_fd;
185     handle->setnonblock_op = pcap_setnonblock_fd;
186     handle->stats_op = bt_monitor_stats;
187 
188     handle->fd = socket(AF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI);
189     if (handle->fd < 0) {
190         pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
191             "Can't create raw socket: %s", strerror(errno));
192         return PCAP_ERROR;
193     }
194 
195     handle->buffer = malloc(handle->bufsize);
196     if (!handle->buffer) {
197         pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't allocate dump buffer: %s",
198             pcap_strerror(errno));
199         goto close_fail;
200     }
201 
202     /* Bind socket to the HCI device */
203     addr.hci_family = AF_BLUETOOTH;
204     addr.hci_dev = HCI_DEV_NONE;
205     addr.hci_channel = HCI_CHANNEL_MONITOR;
206 
207     if (bind(handle->fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
208         pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
209             "Can't attach to interface: %s", strerror(errno));
210         goto close_fail;
211     }
212 
213     opt = 1;
214     if (setsockopt(handle->fd, SOL_SOCKET, SO_TIMESTAMP, &opt, sizeof(opt)) < 0) {
215         pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
216             "Can't enable time stamp: %s", strerror(errno));
217         goto close_fail;
218     }
219 
220     handle->selectable_fd = handle->fd;
221 
222     return 0;
223 
224 close_fail:
225     pcap_cleanup_live_common(handle);
226     return err;
227 }
228 
229 pcap_t *
bt_monitor_create(const char * device,char * ebuf,int * is_ours)230 bt_monitor_create(const char *device, char *ebuf, int *is_ours)
231 {
232     pcap_t      *p;
233     const char  *cp;
234 
235     cp = strrchr(device, '/');
236     if (cp == NULL)
237         cp = device;
238 
239     if (strcmp(cp, INTERFACE_NAME) != 0) {
240         *is_ours = 0;
241         return NULL;
242     }
243 
244     *is_ours = 1;
245     p = pcap_create_common(ebuf, 0);
246     if (p == NULL)
247         return NULL;
248 
249     p->activate_op = bt_monitor_activate;
250 
251     return p;
252 }
253