/*
   * Copyright (c) 2014 Michal Labedzki for Tieto Corporation
   * 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.
   *
   */
  
  #ifdef HAVE_CONFIG_H
  #include <config.h>
  #endif
  
  #include <errno.h>
  #include <stdint.h>
  #include <stdlib.h>
  #include <string.h>
  
  #include <bluetooth/bluetooth.h>
  #include <bluetooth/hci.h>
  
  #include "pcap/bluetooth.h"
  #include "pcap-int.h"
  
  #include "pcap-bt-monitor-linux.h"
  
  #define BT_CONTROL_SIZE 32
  #define INTERFACE_NAME "bluetooth-monitor"
  
  /*
   * Fields and alignment must match the declaration in the Linux kernel 3.4+.
   * See struct hci_mon_hdr in include/net/bluetooth/hci_mon.h.
   */
  struct hci_mon_hdr {
      uint16_t opcode;
      uint16_t index;
      uint16_t len;
  } __attribute__((packed));
  
  int
  bt_monitor_findalldevs(pcap_if_list_t *devlistp, char *err_str)
  {
      int         ret = 0;
  
      /*
       * Bluetooth is a wireless technology.
       *
       * This is a device to monitor all Bluetooth interfaces, so
       * there's no notion of "connected" or "disconnected", any
       * more than there's a notion of "connected" or "disconnected"
       * for the "any" device.
       */
      if (add_dev(devlistp, INTERFACE_NAME,
                  PCAP_IF_WIRELESS|PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE,
                  "Bluetooth Linux Monitor", err_str) == NULL)
      {
          ret = -1;
      }
  
      return ret;
  }
  
  static int
  bt_monitor_read(pcap_t *handle, int max_packets _U_, pcap_handler callback, u_char *user)
  {
      struct cmsghdr *cmsg;
      struct msghdr msg;
      struct iovec  iv[2];
      ssize_t ret;
      struct pcap_pkthdr pkth;
      pcap_bluetooth_linux_monitor_header *bthdr;
      u_char *pktd;
      struct hci_mon_hdr hdr;
  
      pktd = (u_char *)handle->buffer + BT_CONTROL_SIZE;
      bthdr = (pcap_bluetooth_linux_monitor_header*)(void *)pktd;
  
      iv[0].iov_base = &hdr;
      iv[0].iov_len = sizeof(hdr);
      iv[1].iov_base = pktd + sizeof(pcap_bluetooth_linux_monitor_header);
      iv[1].iov_len = handle->snapshot;
  
      memset(&pkth.ts, 0, sizeof(pkth.ts));
      memset(&msg, 0, sizeof(msg));
      msg.msg_iov = iv;
      msg.msg_iovlen = 2;
      msg.msg_control = handle->buffer;
      msg.msg_controllen = BT_CONTROL_SIZE;
  
      do {
          ret = recvmsg(handle->fd, &msg, 0);
          if (handle->break_loop)
          {
              handle->break_loop = 0;
              return -2;
          }
      } while ((ret == -1) && (errno == EINTR));
  
      if (ret < 0) {
          pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
              errno, "Can't receive packet");
          return -1;
      }
  
      pkth.caplen = ret - sizeof(hdr) + sizeof(pcap_bluetooth_linux_monitor_header);
      pkth.len = pkth.caplen;
  
      for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
          if (cmsg->cmsg_level != SOL_SOCKET) continue;
  
          if (cmsg->cmsg_type == SCM_TIMESTAMP) {
              memcpy(&pkth.ts, CMSG_DATA(cmsg), sizeof(pkth.ts));
          }
      }
  
      bthdr->adapter_id = htons(hdr.index);
      bthdr->opcode = htons(hdr.opcode);
  
      if (handle->fcode.bf_insns == NULL ||
          bpf_filter(handle->fcode.bf_insns, pktd, pkth.len, pkth.caplen)) {
          callback(user, &pkth, pktd);
          return 1;
      }
      return 0;   /* didn't pass filter */
  }
  
  static int
  bt_monitor_inject(pcap_t *handle, const void *buf _U_, size_t size _U_)
  {
      pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "inject not supported yet");
      return -1;
  }
  
  static int
  bt_monitor_setdirection(pcap_t *p, pcap_direction_t d)
  {
      p->direction = d;
      return 0;
  }
  
  static int
  bt_monitor_stats(pcap_t *handle _U_, struct pcap_stat *stats)
  {
      stats->ps_recv = 0;
      stats->ps_drop = 0;
      stats->ps_ifdrop = 0;
  
      return 0;
  }
  
  static int
  bt_monitor_activate(pcap_t* handle)
  {
      struct sockaddr_hci addr;
      int err = PCAP_ERROR;
      int opt;
  
      if (handle->opt.rfmon) {
          /* monitor mode doesn't apply here */
          return PCAP_ERROR_RFMON_NOTSUP;
      }
  
      /*
       * Turn a negative snapshot value (invalid), a snapshot value of
       * 0 (unspecified), or a value bigger than the normal maximum
       * value, into the maximum allowed value.
       *
       * If some application really *needs* a bigger snapshot
       * length, we should just increase MAXIMUM_SNAPLEN.
       */
      if (handle->snapshot <= 0 || handle->snapshot > MAXIMUM_SNAPLEN)
          handle->snapshot = MAXIMUM_SNAPLEN;
  
      handle->bufsize = BT_CONTROL_SIZE + sizeof(pcap_bluetooth_linux_monitor_header) + handle->snapshot;
      handle->linktype = DLT_BLUETOOTH_LINUX_MONITOR;
  
      handle->read_op = bt_monitor_read;
      handle->inject_op = bt_monitor_inject;
      handle->setfilter_op = install_bpf_program; /* no kernel filtering */
      handle->setdirection_op = bt_monitor_setdirection;
      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_monitor_stats;
  
      handle->fd = socket(AF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI);
      if (handle->fd < 0) {
          pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
              errno, "Can't create raw socket");
          return PCAP_ERROR;
      }
  
      handle->buffer = malloc(handle->bufsize);
      if (!handle->buffer) {
          pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
              errno, "Can't allocate dump buffer");
          goto close_fail;
      }
  
      /* Bind socket to the HCI device */
      addr.hci_family = AF_BLUETOOTH;
      addr.hci_dev = HCI_DEV_NONE;
      addr.hci_channel = HCI_CHANNEL_MONITOR;
  
      if (bind(handle->fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
          pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
              errno, "Can't attach to interface");
          goto close_fail;
      }
  
      opt = 1;
      if (setsockopt(handle->fd, SOL_SOCKET, SO_TIMESTAMP, &opt, sizeof(opt)) < 0) {
          pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
              errno, "Can't enable time stamp");
          goto close_fail;
      }
  
      handle->selectable_fd = handle->fd;
  
      return 0;
  
  close_fail:
      pcap_cleanup_live_common(handle);
      return err;
  }
  
  pcap_t *
  bt_monitor_create(const char *device, char *ebuf, int *is_ours)
  {
      pcap_t      *p;
      const char  *cp;
  
      cp = strrchr(device, '/');
      if (cp == NULL)
          cp = device;
  
      if (strcmp(cp, INTERFACE_NAME) != 0) {
          *is_ours = 0;
          return NULL;
      }
  
      *is_ours = 1;
      p = pcap_create_common(ebuf, 0);
      if (p == NULL)
          return NULL;
  
      p->activate_op = bt_monitor_activate;
  
      return p;
  }