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pcap-bt-linux.c

/*
 * Copyright (c) 2006 Paolo Abeni (Italy)
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote 
 * products derived from this software without specific prior written 
 * permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Bluetooth sniffing API implementation for Linux platform
 * By Paolo Abeni <paolo.abeni@email.it>
 *
 */
#ifndef lint
static const char rcsid[] _U_ =
    "@(#) $Header: /tcpdump/master/libpcap/pcap-bt-linux.c,v 1.9.2.6 2008-07-01 07:06:37 guy Exp $ (LBL)";
#endif
 
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "pcap-int.h"
#include "pcap-bt-linux.h"
#include "pcap/bluetooth.h"

#ifdef NEED_STRERROR_H
#include "strerror.h"
#endif

#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <arpa/inet.h>

#include <bluetooth/bluetooth.h>
#include <bluetooth/hci.h>

#define BT_IFACE "bluetooth"
#define BT_CTRL_SIZE 128

/* forward declaration */
static int bt_activate(pcap_t *);
static int bt_read_linux(pcap_t *, int , pcap_handler , u_char *);
static int bt_inject_linux(pcap_t *, const void *, size_t);
static int bt_setfilter_linux(pcap_t *, struct bpf_program *);
static int bt_setdirection_linux(pcap_t *, pcap_direction_t);
static int bt_stats_linux(pcap_t *, struct pcap_stat *);

int 
bt_platform_finddevs(pcap_if_t **alldevsp, char *err_str)
{
      pcap_if_t *found_dev = *alldevsp;
      struct hci_dev_list_req *dev_list;
      struct hci_dev_req *dev_req;
      int i, sock;
      int ret = 0;
      
      sock  = socket(AF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI);
      if (sock < 0)
      {
            /* if bluetooth is not supported this this is not fatal*/ 
            if (errno == EAFNOSUPPORT)
                  return 0;
            snprintf(err_str, PCAP_ERRBUF_SIZE, "Can't open raw Bluetooth socket %d:%s",
                  errno, strerror(errno));
            return -1;
      }

      dev_list = malloc(HCI_MAX_DEV * sizeof(*dev_req) + sizeof(*dev_list));
      if (!dev_list) 
      {
            snprintf(err_str, PCAP_ERRBUF_SIZE, "Can't allocate %zu bytes for Bluetooth device list",
                  HCI_MAX_DEV * sizeof(*dev_req) + sizeof(*dev_list));
            ret = -1;
            goto done;
      }

      dev_list->dev_num = HCI_MAX_DEV;

      if (ioctl(sock, HCIGETDEVLIST, (void *) dev_list) < 0) 
      {
            snprintf(err_str, PCAP_ERRBUF_SIZE, "Can't get Bluetooth device list via ioctl %d:%s",
                  errno, strerror(errno));
            ret = -1;
            goto free;
      }

      dev_req = dev_list->dev_req;
      for (i = 0; i < dev_list->dev_num; i++, dev_req++) {
            char dev_name[20], dev_descr[30];
            
            snprintf(dev_name, 20, BT_IFACE"%d", dev_req->dev_id);
            snprintf(dev_descr, 30, "Bluetooth adapter number %d", i);
                  
            if (pcap_add_if(&found_dev, dev_name, 0, 
                   dev_descr, err_str) < 0)
            {
                  ret = -1;
                  break;
            }

      }

free:
      free(dev_list);

done:
      close(sock);
      return ret;
}

pcap_t *
bt_create(const char *device, char *ebuf)
{
      pcap_t *p;

      p = pcap_create_common(device, ebuf);
      if (p == NULL)
            return (NULL);

      p->activate_op = bt_activate;
      return (p);
}

static int
bt_activate(pcap_t* handle)
{
      struct sockaddr_hci addr;
      int opt;
      int         dev_id;
      struct hci_filter flt;
      int err = PCAP_ERROR;

      /* get bt interface id */
      if (sscanf(handle->opt.source, BT_IFACE"%d", &dev_id) != 1)
      {
            snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
                  "Can't get Bluetooth device index from %s", 
                   handle->opt.source);
            return PCAP_ERROR;
      }

      /* Initialize some components of the pcap structure. */
      handle->bufsize = handle->snapshot+BT_CTRL_SIZE+sizeof(pcap_bluetooth_h4_header);
      handle->offset = BT_CTRL_SIZE;
      handle->linktype = DLT_BLUETOOTH_HCI_H4_WITH_PHDR;

      handle->read_op = bt_read_linux;
      handle->inject_op = bt_inject_linux;
      handle->setfilter_op = bt_setfilter_linux;
      handle->setdirection_op = bt_setdirection_linux;
      handle->set_datalink_op = NULL;     /* can't change data link type */
      handle->getnonblock_op = pcap_getnonblock_fd;
      handle->setnonblock_op = pcap_setnonblock_fd;
      handle->stats_op = bt_stats_linux;
      handle->md.ifindex = dev_id;
      
      /* Create HCI socket */
      handle->fd = socket(AF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI);
      if (handle->fd < 0) {
            snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't create raw socket %d:%s",
                  errno, strerror(errno));
            return PCAP_ERROR;
      }

      handle->buffer = malloc(handle->bufsize);
      if (!handle->buffer) {
            snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't allocate dump buffer: %s",
                  pcap_strerror(errno));
            goto close_fail;
      }

      opt = 1;
      if (setsockopt(handle->fd, SOL_HCI, HCI_DATA_DIR, &opt, sizeof(opt)) < 0) {
            snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't enable data direction info %d:%s",
                  errno, strerror(errno));
            goto close_fail;
      }

      opt = 1;
      if (setsockopt(handle->fd, SOL_HCI, HCI_TIME_STAMP, &opt, sizeof(opt)) < 0) {
            snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't enable time stamp %d:%s",
                  errno, strerror(errno));
            goto close_fail;
      }

      /* Setup filter, do not call hci function to avoid dependence on 
       * external libs  */
      memset(&flt, 0, sizeof(flt));
      memset((void *) &flt.type_mask, 0xff, sizeof(flt.type_mask));     
      memset((void *) &flt.event_mask, 0xff, sizeof(flt.event_mask));
      if (setsockopt(handle->fd, SOL_HCI, HCI_FILTER, &flt, sizeof(flt)) < 0) {
            snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't set filter %d:%s",
                  errno, strerror(errno));
            goto close_fail;
      }


      /* Bind socket to the HCI device */
      addr.hci_family = AF_BLUETOOTH;
      addr.hci_dev = handle->md.ifindex;
      if (bind(handle->fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
            snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't attach to device %d %d:%s",
                  handle->md.ifindex, errno, strerror(errno));
            goto close_fail;
      }

      if (handle->opt.rfmon) {
            /*
             * Monitor mode doesn't apply to Bluetooth devices.
             */
            err = PCAP_ERROR_RFMON_NOTSUP;
            goto close_fail;
      }

      if (handle->opt.buffer_size == 0) {
            /*
             * Set the socket buffer size to the specified value.
             */
            if (setsockopt(handle->fd, SOL_SOCKET, SO_RCVBUF,
                &handle->opt.buffer_size,
                sizeof(handle->opt.buffer_size)) == -1) {
                  snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
                         "SO_RCVBUF: %s", pcap_strerror(errno));
                  goto close_fail;
            }
      }

      handle->selectable_fd = handle->fd;
      return 0;

close_fail:
      pcap_cleanup_live_common(handle);
      return err;
}

static int
bt_read_linux(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
{
      struct cmsghdr *cmsg;
      struct msghdr msg;
      struct iovec  iv;
      struct pcap_pkthdr pkth;
      pcap_bluetooth_h4_header* bthdr;

      bthdr = (pcap_bluetooth_h4_header*) &handle->buffer[handle->offset];
      iv.iov_base = &handle->buffer[handle->offset+sizeof(pcap_bluetooth_h4_header)];
      iv.iov_len  = handle->snapshot;
      
      memset(&msg, 0, sizeof(msg));
      msg.msg_iov = &iv;
      msg.msg_iovlen = 1;
      msg.msg_control = handle->buffer;
      msg.msg_controllen = handle->offset;

      /* ignore interrupt system call error */
      do {
            pkth.caplen = recvmsg(handle->fd, &msg, 0);
            if (handle->break_loop)
            {
                  handle->break_loop = 0;
                  return -2;
            }
      } while ((pkth.caplen == -1) && (errno == EINTR));

            
      if (pkth.caplen < 0) {
            snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't receive packet %d:%s",
                  errno, strerror(errno));
            return -1;
      }

      /* get direction and timestamp*/ 
      cmsg = CMSG_FIRSTHDR(&msg);
      int in=0;
      while (cmsg) {
            switch (cmsg->cmsg_type) {
                  case HCI_CMSG_DIR:
                        in = *((int *) CMSG_DATA(cmsg));
                        break;
                        case HCI_CMSG_TSTAMP:
                        pkth.ts = *((struct timeval *) CMSG_DATA(cmsg));
                        break;
            }
            cmsg = CMSG_NXTHDR(&msg, cmsg);
      }
      if ((in && (handle->direction == PCAP_D_OUT)) || 
                        ((!in) && (handle->direction == PCAP_D_IN)))
            return 0;

      bthdr->direction = htonl(in != 0);
      pkth.caplen+=sizeof(pcap_bluetooth_h4_header);
      pkth.len = pkth.caplen;
      callback(user, &pkth, &handle->buffer[handle->offset]);
      return 1;
}

static int
bt_inject_linux(pcap_t *handle, const void *buf, size_t size)
{
      snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "inject not supported on "
            "bluetooth devices");
      return (-1);
}                           


static int 
bt_stats_linux(pcap_t *handle, struct pcap_stat *stats)
{
      int ret;
      struct hci_dev_info dev_info;
      struct hci_dev_stats * s = &dev_info.stat;
      dev_info.dev_id = handle->md.ifindex;
      
      /* ingnore eintr */
      do {
            ret = ioctl(handle->fd, HCIGETDEVINFO, (void *)&dev_info);
      } while ((ret == -1) && (errno == EINTR));
          
      if (ret < 0) {
            snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "can get stats"
                  " via ioctl %d:%s", errno, strerror(errno));
            return (-1);
            
      }

      /* we receive both rx and tx frames, so comulate all stats */     
      stats->ps_recv = s->evt_rx + s->acl_rx + s->sco_rx + s->cmd_tx + 
            s->acl_tx +s->sco_tx;
      stats->ps_drop = s->err_rx + s->err_tx;
      stats->ps_ifdrop = 0;
      return 0;
}

static int 
bt_setfilter_linux(pcap_t *p, struct bpf_program *fp)
{
      return 0;
}


static int 
bt_setdirection_linux(pcap_t *p, pcap_direction_t d)
{
      p->direction = d;
      return 0;
}

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