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_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
  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     struct hci_mon_hdr hdr;
  86
  87     bthdr = (pcap_bluetooth_linux_monitor_header*) &handle->buffer[handle->offset];
  88
  89     iv[0].iov_base = &hdr;
  90     iv[0].iov_len = sizeof(hdr);
  91     iv[1].iov_base = &handle->buffer[handle->offset + sizeof(pcap_bluetooth_linux_monitor_header)];
  92     iv[1].iov_len = handle->snapshot;
  93
  94     memset(&pkth.ts, 0, sizeof(pkth.ts));
  95     memset(&msg, 0, sizeof(msg));
  96     msg.msg_iov = iv;
  97     msg.msg_iovlen = 2;
  98     msg.msg_control = handle->buffer;
  99     msg.msg_controllen = handle->offset;
 100
 101     do {
 102         ret = recvmsg(handle->fd, &msg, 0);
 103         if (handle->break_loop)
 104         {
 105             handle->break_loop = 0;
 106             return -2;
 107         }
 108     } while ((ret == -1) && (errno == EINTR));
 109
 110     if (ret < 0) {
 111         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 112             "Can't receive packet: %s", strerror(errno));
 113         return -1;
 114     }
 115
 116     pkth.caplen = ret - sizeof(hdr) + sizeof(pcap_bluetooth_linux_monitor_header);
 117     pkth.len = pkth.caplen;
 118
 119     for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
 120         if (cmsg->cmsg_level != SOL_SOCKET) continue;
 121
 122         if (cmsg->cmsg_type == SCM_TIMESTAMP) {
 123             memcpy(&pkth.ts, CMSG_DATA(cmsg), sizeof(pkth.ts));
 124         }
 125     }
 126
 127     bthdr->adapter_id = htons(hdr.index);
 128     bthdr->opcode = htons(hdr.opcode);
 129
 130     if (handle->fcode.bf_insns == NULL ||
 131         bpf_filter(handle->fcode.bf_insns, &handle->buffer[handle->offset],
 132           pkth.len, pkth.caplen)) {
 133         callback(user, &pkth, &handle->buffer[handle->offset]);
 134         return 1;
 135     }
 136     return 0;   /* didn't pass filter */
 137 }
 138
 139 static int
 140 bt_monitor_inject(pcap_t *handle, const void *buf _U_, size_t size _U_)
 141 {
 142     snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "inject not supported yet");
 143     return -1;
 144 }
 145
 146 static int
 147 bt_monitor_setdirection(pcap_t *p, pcap_direction_t d)
 148 {
 149     p->direction = d;
 150     return 0;
 151 }
 152
 153 static int
 154 bt_monitor_stats(pcap_t *handle _U_, struct pcap_stat *stats)
 155 {
 156     stats->ps_recv = 0;
 157     stats->ps_drop = 0;
 158     stats->ps_ifdrop = 0;
 159
 160     return 0;
 161 }
 162
 163 static int
 164 bt_monitor_activate(pcap_t* handle)
 165 {
 166     struct sockaddr_hci addr;
 167     int err = PCAP_ERROR;
 168     int opt;
 169
 170     if (handle->opt.rfmon) {
 171         /* monitor mode doesn't apply here */
 172         return PCAP_ERROR_RFMON_NOTSUP;
 173     }
 174
 175     handle->bufsize = handle->snapshot + BT_CONTROL_SIZE + sizeof(pcap_bluetooth_linux_monitor_header);
 176     handle->offset = BT_CONTROL_SIZE;
 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         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         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         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         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 *
 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(device, ebuf, 0);
 246     if (p == NULL)
 247         return NULL;
 248
 249     p->activate_op = bt_monitor_activate;
 250
 251     return p;
 252 }