The Tcpdump Group git mirrors - libpcap/blob - pcap-bt-monitor-linux.c

   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 }