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 #include <config.h>
  33
  34 #include <errno.h>
  35 #include <stdint.h>
  36 #include <stdlib.h>
  37 #include <string.h>
  38
  39 #include <bluetooth/bluetooth.h>
  40 #include <bluetooth/hci.h>
  41
  42 #include "pcap/bluetooth.h"
  43 #include "pcap-int.h"
  44 #include "diag-control.h"
  45
  46 #include "pcap-bt-monitor-linux.h"
  47
  48 #define BT_CONTROL_SIZE 32
  49 #define INTERFACE_NAME "bluetooth-monitor"
  50
  51 /*
  52  * Private data.
  53  * Currently contains nothing.
  54  */
  55 struct pcap_bt_monitor {
  56         int     dummy;
  57 };
  58
  59 /*
  60  * Fields and alignment must match the declaration in the Linux kernel 3.4+.
  61  * See struct hci_mon_hdr in include/net/bluetooth/hci_mon.h.
  62  */
  63 struct hci_mon_hdr {
  64     uint16_t opcode;
  65     uint16_t index;
  66     uint16_t len;
  67 } __attribute__((packed));
  68
  69 int
  70 bt_monitor_findalldevs(pcap_if_list_t *devlistp, char *err_str)
  71 {
  72     int         ret = 0;
  73
  74     /*
  75      * Bluetooth is a wireless technology.
  76      *
  77      * This is a device to monitor all Bluetooth interfaces, so
  78      * there's no notion of "connected" or "disconnected", any
  79      * more than there's a notion of "connected" or "disconnected"
  80      * for the "any" device.
  81      */
  82     if (pcapint_add_dev(devlistp, INTERFACE_NAME,
  83                 PCAP_IF_WIRELESS|PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE,
  84                 "Bluetooth Linux Monitor", err_str) == NULL)
  85     {
  86         ret = PCAP_ERROR;
  87     }
  88
  89     return ret;
  90 }
  91
  92 static int
  93 bt_monitor_read(pcap_t *handle, int max_packets _U_, pcap_handler callback, u_char *user)
  94 {
  95     struct cmsghdr *cmsg;
  96     struct msghdr msg;
  97     struct iovec  iv[2];
  98     ssize_t ret;
  99     struct pcap_pkthdr pkth;
 100     pcap_bluetooth_linux_monitor_header *bthdr;
 101     u_char *pktd;
 102     struct hci_mon_hdr hdr;
 103
 104     pktd = handle->buffer + BT_CONTROL_SIZE;
 105     bthdr = (pcap_bluetooth_linux_monitor_header*)(void *)pktd;
 106
 107     iv[0].iov_base = &hdr;
 108     iv[0].iov_len = sizeof(hdr);
 109     iv[1].iov_base = pktd + sizeof(pcap_bluetooth_linux_monitor_header);
 110     iv[1].iov_len = handle->snapshot;
 111
 112     memset(&pkth.ts, 0, sizeof(pkth.ts));
 113     memset(&msg, 0, sizeof(msg));
 114     msg.msg_iov = iv;
 115     msg.msg_iovlen = 2;
 116     msg.msg_control = handle->buffer;
 117     msg.msg_controllen = BT_CONTROL_SIZE;
 118
 119     do {
 120         if (handle->break_loop)
 121         {
 122             handle->break_loop = 0;
 123             return PCAP_ERROR_BREAK;
 124         }
 125         ret = recvmsg(handle->fd, &msg, 0);
 126     } while ((ret == -1) && (errno == EINTR));
 127
 128     if (ret < 0) {
 129         if (errno == EAGAIN || errno == EWOULDBLOCK) {
 130             /* Nonblocking mode, no data */
 131             return 0;
 132         }
 133         pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
 134             errno, "Can't receive packet");
 135         return PCAP_ERROR;
 136     }
 137
 138     pkth.caplen = (bpf_u_int32)(ret - sizeof(hdr) + sizeof(pcap_bluetooth_linux_monitor_header));
 139     pkth.len = pkth.caplen;
 140
 141     // for musl libc CMSG_NXTHDR()
 142 DIAG_OFF_SIGN_COMPARE
 143     for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
 144 DIAG_ON_SIGN_COMPARE
 145         if (cmsg->cmsg_level != SOL_SOCKET) continue;
 146
 147         if (cmsg->cmsg_type == SCM_TIMESTAMP) {
 148             memcpy(&pkth.ts, CMSG_DATA(cmsg), sizeof(pkth.ts));
 149         }
 150     }
 151
 152     bthdr->adapter_id = htons(hdr.index);
 153     bthdr->opcode = htons(hdr.opcode);
 154
 155     if (handle->fcode.bf_insns == NULL ||
 156         pcapint_filter(handle->fcode.bf_insns, pktd, pkth.len, pkth.caplen)) {
 157         callback(user, &pkth, pktd);
 158         return 1;
 159     }
 160     return 0;   /* didn't pass filter */
 161 }
 162
 163 static int
 164 bt_monitor_inject(pcap_t *handle, const void *buf _U_, int size _U_)
 165 {
 166     snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 167         "Packet injection is not supported yet on Bluetooth monitor devices");
 168     return PCAP_ERROR;
 169 }
 170
 171 static int
 172 bt_monitor_stats(pcap_t *handle _U_, struct pcap_stat *stats)
 173 {
 174     stats->ps_recv = 0;
 175     stats->ps_drop = 0;
 176     stats->ps_ifdrop = 0;
 177
 178     return 0;
 179 }
 180
 181 static int
 182 bt_monitor_activate(pcap_t* handle)
 183 {
 184     struct sockaddr_hci addr;
 185     int err = PCAP_ERROR;
 186     int opt;
 187
 188     if (handle->opt.rfmon) {
 189         /* monitor mode doesn't apply here */
 190         return PCAP_ERROR_RFMON_NOTSUP;
 191     }
 192
 193     /*
 194      * Turn a negative snapshot value (invalid), a snapshot value of
 195      * 0 (unspecified), or a value bigger than the normal maximum
 196      * value, into the maximum allowed value.
 197      *
 198      * If some application really *needs* a bigger snapshot
 199      * length, we should just increase MAXIMUM_SNAPLEN.
 200      */
 201     if (handle->snapshot <= 0 || handle->snapshot > MAXIMUM_SNAPLEN)
 202         handle->snapshot = MAXIMUM_SNAPLEN;
 203
 204     handle->bufsize = BT_CONTROL_SIZE + sizeof(pcap_bluetooth_linux_monitor_header) + handle->snapshot;
 205     handle->linktype = DLT_BLUETOOTH_LINUX_MONITOR;
 206
 207     handle->read_op = bt_monitor_read;
 208     handle->inject_op = bt_monitor_inject;
 209     handle->setfilter_op = pcapint_install_bpf_program; /* no kernel filtering */
 210     handle->setdirection_op = NULL; /* Not implemented */
 211     handle->set_datalink_op = NULL; /* can't change data link type */
 212     handle->getnonblock_op = pcapint_getnonblock_fd;
 213     handle->setnonblock_op = pcapint_setnonblock_fd;
 214     handle->stats_op = bt_monitor_stats;
 215
 216     handle->fd = socket(AF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI);
 217     if (handle->fd < 0) {
 218         pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
 219             errno, "Can't create raw socket");
 220         return PCAP_ERROR;
 221     }
 222
 223     handle->buffer = malloc(handle->bufsize);
 224     if (!handle->buffer) {
 225         pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
 226             errno, "Can't allocate dump buffer");
 227         goto close_fail;
 228     }
 229
 230     /* Bind socket to the HCI device */
 231     addr.hci_family = AF_BLUETOOTH;
 232     addr.hci_dev = HCI_DEV_NONE;
 233     addr.hci_channel = HCI_CHANNEL_MONITOR;
 234
 235     if (bind(handle->fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
 236         pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
 237             errno, "Can't attach to interface");
 238         goto close_fail;
 239     }
 240
 241     opt = 1;
 242     if (setsockopt(handle->fd, SOL_SOCKET, SO_TIMESTAMP, &opt, sizeof(opt)) < 0) {
 243         pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
 244             errno, "Can't enable time stamp");
 245         goto close_fail;
 246     }
 247
 248     handle->selectable_fd = handle->fd;
 249
 250     return 0;
 251
 252 close_fail:
 253     pcapint_cleanup_live_common(handle);
 254     return err;
 255 }
 256
 257 pcap_t *
 258 bt_monitor_create(const char *device, char *ebuf, int *is_ours)
 259 {
 260     pcap_t      *p;
 261
 262     if (strcmp(device, INTERFACE_NAME) != 0) {
 263         *is_ours = 0;
 264         return NULL;
 265     }
 266
 267     *is_ours = 1;
 268     p = PCAP_CREATE_COMMON(ebuf, struct pcap_bt_monitor);
 269     if (p == NULL)
 270         return NULL;
 271
 272     p->activate_op = bt_monitor_activate;
 273
 274     return p;
 275 }