/*

 * 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 = &hd;;

    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,

        "Packet injection is not supported yet on Bluetooth monitor devices");

    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;

}