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 (pcap_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 = 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         if (errno == EAGAIN || errno == EWOULDBLOCK) {
 131             /* Nonblocking mode, no data */
 132             return 0;
 133         }
 134         pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
 135             errno, "Can't receive packet");
 136         return -1;
 137     }
 138
 139     pkth.caplen = (bpf_u_int32)(ret - sizeof(hdr) + sizeof(pcap_bluetooth_linux_monitor_header));
 140     pkth.len = pkth.caplen;
 141
 142     for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
 143         if (cmsg->cmsg_level != SOL_SOCKET) continue;
 144
 145         if (cmsg->cmsg_type == SCM_TIMESTAMP) {
 146             memcpy(&pkth.ts, CMSG_DATA(cmsg), sizeof(pkth.ts));
 147         }
 148     }
 149
 150     bthdr->adapter_id = htons(hdr.index);
 151     bthdr->opcode = htons(hdr.opcode);
 152
 153     if (handle->fcode.bf_insns == NULL ||
 154         pcap_filter(handle->fcode.bf_insns, pktd, pkth.len, pkth.caplen)) {
 155         callback(user, &pkth, pktd);
 156         return 1;
 157     }
 158     return 0;   /* didn't pass filter */
 159 }
 160
 161 static int
 162 bt_monitor_inject(pcap_t *handle, const void *buf _U_, int size _U_)
 163 {
 164     snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 165         "Packet injection is not supported yet on Bluetooth monitor devices");
 166     return -1;
 167 }
 168
 169 static int
 170 bt_monitor_stats(pcap_t *handle _U_, struct pcap_stat *stats)
 171 {
 172     stats->ps_recv = 0;
 173     stats->ps_drop = 0;
 174     stats->ps_ifdrop = 0;
 175
 176     return 0;
 177 }
 178
 179 static int
 180 bt_monitor_activate(pcap_t* handle)
 181 {
 182     struct sockaddr_hci addr;
 183     int err = PCAP_ERROR;
 184     int opt;
 185
 186     if (handle->opt.rfmon) {
 187         /* monitor mode doesn't apply here */
 188         return PCAP_ERROR_RFMON_NOTSUP;
 189     }
 190
 191     /*
 192      * Turn a negative snapshot value (invalid), a snapshot value of
 193      * 0 (unspecified), or a value bigger than the normal maximum
 194      * value, into the maximum allowed value.
 195      *
 196      * If some application really *needs* a bigger snapshot
 197      * length, we should just increase MAXIMUM_SNAPLEN.
 198      */
 199     if (handle->snapshot <= 0 || handle->snapshot > MAXIMUM_SNAPLEN)
 200         handle->snapshot = MAXIMUM_SNAPLEN;
 201
 202     handle->bufsize = BT_CONTROL_SIZE + sizeof(pcap_bluetooth_linux_monitor_header) + handle->snapshot;
 203     handle->linktype = DLT_BLUETOOTH_LINUX_MONITOR;
 204
 205     handle->read_op = bt_monitor_read;
 206     handle->inject_op = bt_monitor_inject;
 207     handle->setfilter_op = pcap_install_bpf_program; /* no kernel filtering */
 208     handle->setdirection_op = NULL; /* Not implemented */
 209     handle->set_datalink_op = NULL; /* can't change data link type */
 210     handle->getnonblock_op = pcap_getnonblock_fd;
 211     handle->setnonblock_op = pcap_setnonblock_fd;
 212     handle->stats_op = bt_monitor_stats;
 213
 214     handle->fd = socket(AF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI);
 215     if (handle->fd < 0) {
 216         pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
 217             errno, "Can't create raw socket");
 218         return PCAP_ERROR;
 219     }
 220
 221     handle->buffer = malloc(handle->bufsize);
 222     if (!handle->buffer) {
 223         pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
 224             errno, "Can't allocate dump buffer");
 225         goto close_fail;
 226     }
 227
 228     /* Bind socket to the HCI device */
 229     addr.hci_family = AF_BLUETOOTH;
 230     addr.hci_dev = HCI_DEV_NONE;
 231     addr.hci_channel = HCI_CHANNEL_MONITOR;
 232
 233     if (bind(handle->fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
 234         pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
 235             errno, "Can't attach to interface");
 236         goto close_fail;
 237     }
 238
 239     opt = 1;
 240     if (setsockopt(handle->fd, SOL_SOCKET, SO_TIMESTAMP, &opt, sizeof(opt)) < 0) {
 241         pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
 242             errno, "Can't enable time stamp");
 243         goto close_fail;
 244     }
 245
 246     handle->selectable_fd = handle->fd;
 247
 248     return 0;
 249
 250 close_fail:
 251     pcap_cleanup_live_common(handle);
 252     return err;
 253 }
 254
 255 pcap_t *
 256 bt_monitor_create(const char *device, char *ebuf, int *is_ours)
 257 {
 258     pcap_t      *p;
 259     const char  *cp;
 260
 261     cp = strrchr(device, '/');
 262     if (cp == NULL)
 263         cp = device;
 264
 265     if (strcmp(cp, INTERFACE_NAME) != 0) {
 266         *is_ours = 0;
 267         return NULL;
 268     }
 269
 270     *is_ours = 1;
 271     p = PCAP_CREATE_COMMON(ebuf, struct pcap_bt_monitor);
 272     if (p == NULL)
 273         return NULL;
 274
 275     p->activate_op = bt_monitor_activate;
 276
 277     return p;
 278 }