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 = (bpf_u_int32)(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         pcap_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_, int size _U_)
 151 {
 152     snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 153         "Packet injection is not supported yet on Bluetooth monitor devices");
 154     return -1;
 155 }
 156
 157 static int
 158 bt_monitor_setdirection(pcap_t *p, pcap_direction_t d)
 159 {
 160     p->direction = d;
 161     return 0;
 162 }
 163
 164 static int
 165 bt_monitor_stats(pcap_t *handle _U_, struct pcap_stat *stats)
 166 {
 167     stats->ps_recv = 0;
 168     stats->ps_drop = 0;
 169     stats->ps_ifdrop = 0;
 170
 171     return 0;
 172 }
 173
 174 static int
 175 bt_monitor_activate(pcap_t* handle)
 176 {
 177     struct sockaddr_hci addr;
 178     int err = PCAP_ERROR;
 179     int opt;
 180
 181     if (handle->opt.rfmon) {
 182         /* monitor mode doesn't apply here */
 183         return PCAP_ERROR_RFMON_NOTSUP;
 184     }
 185
 186     /*
 187      * Turn a negative snapshot value (invalid), a snapshot value of
 188      * 0 (unspecified), or a value bigger than the normal maximum
 189      * value, into the maximum allowed value.
 190      *
 191      * If some application really *needs* a bigger snapshot
 192      * length, we should just increase MAXIMUM_SNAPLEN.
 193      */
 194     if (handle->snapshot <= 0 || handle->snapshot > MAXIMUM_SNAPLEN)
 195         handle->snapshot = MAXIMUM_SNAPLEN;
 196
 197     handle->bufsize = BT_CONTROL_SIZE + sizeof(pcap_bluetooth_linux_monitor_header) + handle->snapshot;
 198     handle->linktype = DLT_BLUETOOTH_LINUX_MONITOR;
 199
 200     handle->read_op = bt_monitor_read;
 201     handle->inject_op = bt_monitor_inject;
 202     handle->setfilter_op = install_bpf_program; /* no kernel filtering */
 203     handle->setdirection_op = bt_monitor_setdirection;
 204     handle->set_datalink_op = NULL; /* can't change data link type */
 205     handle->getnonblock_op = pcap_getnonblock_fd;
 206     handle->setnonblock_op = pcap_setnonblock_fd;
 207     handle->stats_op = bt_monitor_stats;
 208
 209     handle->fd = socket(AF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI);
 210     if (handle->fd < 0) {
 211         pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
 212             errno, "Can't create raw socket");
 213         return PCAP_ERROR;
 214     }
 215
 216     handle->buffer = malloc(handle->bufsize);
 217     if (!handle->buffer) {
 218         pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
 219             errno, "Can't allocate dump buffer");
 220         goto close_fail;
 221     }
 222
 223     /* Bind socket to the HCI device */
 224     addr.hci_family = AF_BLUETOOTH;
 225     addr.hci_dev = HCI_DEV_NONE;
 226     addr.hci_channel = HCI_CHANNEL_MONITOR;
 227
 228     if (bind(handle->fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
 229         pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
 230             errno, "Can't attach to interface");
 231         goto close_fail;
 232     }
 233
 234     opt = 1;
 235     if (setsockopt(handle->fd, SOL_SOCKET, SO_TIMESTAMP, &opt, sizeof(opt)) < 0) {
 236         pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
 237             errno, "Can't enable time stamp");
 238         goto close_fail;
 239     }
 240
 241     handle->selectable_fd = handle->fd;
 242
 243     return 0;
 244
 245 close_fail:
 246     pcap_cleanup_live_common(handle);
 247     return err;
 248 }
 249
 250 pcap_t *
 251 bt_monitor_create(const char *device, char *ebuf, int *is_ours)
 252 {
 253     pcap_t      *p;
 254     const char  *cp;
 255
 256     cp = strrchr(device, '/');
 257     if (cp == NULL)
 258         cp = device;
 259
 260     if (strcmp(cp, INTERFACE_NAME) != 0) {
 261         *is_ours = 0;
 262         return NULL;
 263     }
 264
 265     *is_ours = 1;
 266     p = pcap_create_common(ebuf, 0);
 267     if (p == NULL)
 268         return NULL;
 269
 270     p->activate_op = bt_monitor_activate;
 271
 272     return p;
 273 }