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