/*====================================================================*
 *
 *   Copyright (c) 2013 Qualcomm Atheros, Inc.
 *
 *   All rights reserved.
 *
 *   Redistribution and use in source and binary forms, with or
 *   without modification, are permitted (subject to the limitations
 *   in the disclaimer below) provided that the following conditions
 *   are met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   * 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.
 *
 *   * Neither the name of Qualcomm Atheros nor the names of
 *     its contributors may be used to endorse or promote products
 *     derived from this software without specific prior written
 *     permission.
 *
 *   NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE
 *   GRANTED BY THIS LICENSE. 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.
 *
 *--------------------------------------------------------------------*/

/*====================================================================*
 *
 *   ssize_t readpacket (struct channel const * channel, void * memory, ssize_t extent);
 *
 *   channel.h
 *
 *   read one packet from a raw packet channel;
 *
 *   return the packet size on success, 0 on timeout or -1 on error;
 *   dump packets on stdout when the channel VERBOSE flag is set;
 *
 *   constant __MAGIC__ enables code that reads frames from stdin,
 *   instead of the network; you may use it whenever a network or
 *   transmitting device is not available;
 *
 *
 *   Contributor(s):
 *	Charles Maier
 *	Nathaniel Houghton
 *      Werner Henze
 *
 *--------------------------------------------------------------------*/

#ifndef READPACKET_SOURCE
#define READPACKET_SOURCE

#include <stdlib.h>
#include <unistd.h>
#include <memory.h>
#include <errno.h>

#if defined (__linux__)
#include <poll.h>
#endif

#include "../ether/channel.h"
#include "../tools/memory.h"
#include "../tools/error.h"
#include "../tools/flags.h"

#if defined (__MAGIC__)
#include "../tools/hexload.c"
#endif

ssize_t readpacket (struct channel const * channel, void * memory, ssize_t extent)

{

#if defined (__MAGIC__)

	memset (memory, 0, extent);
	extent = hexload (memory, extent, stdin);
	if (_anyset (channel->flags, CHANNEL_VERBOSE))
	{
		hexdump (memory, 0, extent, stdout);
	}
	return (extent);

#elif defined (__linux__)

	struct pollfd pollfd =
	{
		channel->fd,
		POLLIN,
		0
	};
	signed status = poll (&pollfd, 1, channel->capture);
	memset (memory, 0, extent);
	if ((status < 0) && (errno != EINTR))
	{
		error (0, errno, "%s can't poll %s", __func__, channel->ifname);
		return (-1);
	}
	if (status > 0)
	{
		status = recvfrom (channel->fd, memory, extent, 0, (struct sockaddr *) (0), (socklen_t *)(0));
		if (status < 0)
		{
			error (0, errno, "%s can't read %s", __func__, channel->ifname);
			return (-1);
		}
		if (status > 0)
		{
			extent = status;
			if (_anyset (channel->flags, CHANNEL_VERBOSE))
			{
				hexdump (memory, 0, extent, stdout);
			}
			return (extent);
		}
	}

#elif defined (__APPLE__) || defined (__OpenBSD__) || defined (__NetBSD__) || defined (__FreeBSD__)

	struct bpf_hdr * bpf_packet;
	struct bpf * bpf = channel->bpf;;
	memset (memory, 0, extent);
	if (bpf->bpf_bufused <= 0)
	{
		bpf->bpf_bufused = read (channel->fd, bpf->bpf_buffer, bpf->bpf_length);
		bpf->bpf_bp = bpf->bpf_buffer;
	}
	if (bpf->bpf_bufused < 0)
	{
		error (0, errno, "bpf");
		return (-1);
	}
	if (bpf->bpf_bufused > 0)
	{
		bpf_packet = (struct bpf_hdr *)(bpf->bpf_bp);
		if ((size_t) (extent) > bpf_packet->bh_caplen)
		{
			extent = bpf_packet->bh_caplen;
		}
		if ((size_t) (extent) < bpf_packet->bh_caplen)
		{
			if (_anyset (channel->flags, CHANNEL_VERBOSE))
			{
				error (0, 0, "Truncated incoming frame (%u -> %zd bytes)", bpf_packet->bh_caplen, extent);
			}
		}
		memcpy (memory, bpf->bpf_bp + bpf_packet->bh_hdrlen, extent);
		bpf->bpf_bufused -= BPF_WORDALIGN (bpf_packet->bh_hdrlen + bpf_packet->bh_caplen);
		bpf->bpf_bp += BPF_WORDALIGN (bpf_packet->bh_hdrlen + bpf_packet->bh_caplen);
		if (_anyset (channel->flags, CHANNEL_VERBOSE))
		{
			hexdump (memory, 0, extent, stdout);
		}
		return (extent);
	}

#elif defined (WINPCAP) || defined (LIBPCAP)

	struct pcap_pkthdr * header;
	const uint8_t *data;
	signed status = pcap_next_ex (channel->socket, &header, &data);
	memset (memory, 0, extent);
	if (status < 0)
	{
		error (0, errno, "pcap_next_ex");
		return (-1);
	}
	if (status > 0)
	{
		extent = header->caplen;
		memcpy (memory, data, extent);
		if (_anyset (channel->flags, CHANNEL_VERBOSE))
		{
			hexdump (memory, 0, extent, stdout);
		}
		return (extent);
	}

#else
#error "Unknown Environment"
#endif

	return (0);
}


#endif