/*
 * Copyright (c) 2009 Lukas Mejdrech
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted 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.
 * - 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 AUTHOR ``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 AUTHOR 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.
 */

/** @addtogroup netecho
 * @{
 */

/** @file
 * Network echo server.
 *
 * Sockets-based server that echoes incomming messages. If stream mode
 * is selected, accepts incoming connections.
 */

#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <str.h>
#include <task.h>
#include <arg_parse.h>

#include <net/in.h>
#include <net/in6.h>
#include <net/inet.h>
#include <net/socket.h>
#include <net/socket_parse.h>

#include "print_error.h"

#define NAME "netecho"

static int count = -1;
static int family = PF_INET;
static sock_type_t type = SOCK_DGRAM;
static uint16_t port = 7;
static int backlog = 3;
static size_t size = 1024;
static int verbose = 0;

static char *reply = NULL;
static size_t reply_length;

static char *data;

static void echo_print_help(void)
{
	printf(
	    "Network echo server\n"
	    "Usage: " NAME " [options]\n"
	    "Where options are:\n"
	    "-b backlog | --backlog=size\n"
	    "\tThe size of the accepted sockets queue. Only for SOCK_STREAM. "
	    "The default is 3.\n"
	    "\n"
	    "-c count | --count=count\n"
	    "\tThe number of received messages to handle. A negative number "
	    "means infinity. The default is infinity.\n"
	    "\n"
	    "-f protocol_family | --family=protocol_family\n"
	    "\tThe listenning socket protocol family. Only the PF_INET and "
	    "PF_INET6 are supported.\n"
	    "\n"
	    "-h | --help\n"
	    "\tShow this application help.\n"
	    "\n"
	    "-p port_number | --port=port_number\n"
	    "\tThe port number the application should listen at. The default "
	    "is 7.\n"
	    "\n"
	    "-r reply_string | --reply=reply_string\n"
	    "\tThe constant reply string. The default is the original data "
	    "received.\n"
	    "\n"
	    "-s receive_size | --size=receive_size\n"
	    "\tThe maximum receive data size the application should accept. "
	    "The default is 1024 bytes.\n"
	    "\n"
	    "-t socket_type | --type=socket_type\n"
	    "\tThe listenning socket type. Only the SOCK_DGRAM and the "
	    "SOCK_STREAM are supported.\n"
	    "\n"
	    "-v | --verbose\n"
	    "\tShow all output messages.\n"
	);
}

static int netecho_parse_option(int argc, char *argv[], int *index)
{
	int value;
	int rc;

	switch (argv[*index][1]) {
	case 'b':
		rc = arg_parse_int(argc, argv, index, &backlog, 0);
		if (rc != EOK)
			return rc;
		break;
	case 'c':
		rc = arg_parse_int(argc, argv, index, &count, 0);
		if (rc != EOK)
			return rc;
		break;
	case 'f':
		rc = arg_parse_name_int(argc, argv, index, &family, 0,
		    socket_parse_protocol_family);
		if (rc != EOK)
			return rc;
		break;
	case 'h':
		echo_print_help();
		exit(0);
		break;
	case 'p':
		rc = arg_parse_int(argc, argv, index, &value, 0);
		if (rc != EOK)
			return rc;
		port = (uint16_t) value;
		break;
	case 'r':
		rc = arg_parse_string(argc, argv, index, &reply, 0);
		if (rc != EOK)
			return rc;
		break;
	case 's':
		rc = arg_parse_int(argc, argv, index, &value, 0);
		if (rc != EOK)
			return rc;
		size = (value >= 0) ? (size_t) value : 0;
		break;
	case 't':
		rc = arg_parse_name_int(argc, argv, index, &value, 0,
		    socket_parse_socket_type);
		if (rc != EOK)
			return rc;
		type = (sock_type_t) value;
		break;
	case 'v':
		verbose = 1;
		break;
	/* Long options with double dash */
	case '-':
		if (str_lcmp(argv[*index] + 2, "backlog=", 6) == 0) {
			rc = arg_parse_int(argc, argv, index, &backlog, 8);
			if (rc != EOK)
				return rc;
		} else if (str_lcmp(argv[*index] + 2, "count=", 6) == 0) {
			rc = arg_parse_int(argc, argv, index, &count, 8);
			if (rc != EOK)
				return rc;
		} else if (str_lcmp(argv[*index] + 2, "family=", 7) == 0) {
			rc = arg_parse_name_int(argc, argv, index, &family, 9,
			    socket_parse_protocol_family);
			if (rc != EOK)
				return rc;
		} else if (str_lcmp(argv[*index] + 2, "help", 5) == 0) {
			echo_print_help();
			exit(0);
		} else if (str_lcmp(argv[*index] + 2, "port=", 5) == 0) {
			rc = arg_parse_int(argc, argv, index, &value, 7);
			if (rc != EOK)
				return rc;
			port = (uint16_t) value;
		} else if (str_lcmp(argv[*index] + 2, "reply=", 6) == 0) {
			rc = arg_parse_string(argc, argv, index, &reply, 8);
			if (rc != EOK)
				return rc;
		} else if (str_lcmp(argv[*index] + 2, "size=", 5) == 0) {
			rc = arg_parse_int(argc, argv, index, &value, 7);
			if (rc != EOK)
				return rc;
			size = (value >= 0) ? (size_t) value : 0;
		} else if (str_lcmp(argv[*index] + 2, "type=", 5) == 0) {
			rc = arg_parse_name_int(argc, argv, index, &value, 7,
			    socket_parse_socket_type);
			if (rc != EOK)
				return rc;
			type = (sock_type_t) value;
		} else if (str_lcmp(argv[*index] + 2, "verbose", 8) == 0) {
			verbose = 1;
		} else {
			echo_print_help();
			return EINVAL;
		}
		break;
	default:
		echo_print_help();
		return EINVAL;
	}

	return EOK;
}

/** Echo one message (accept one connection and echo message).
 *
 * @param listening_id	Listening socket.
 * @return		EOK on success or negative error code.
 */
static int netecho_socket_process_message(int listening_id)
{
	uint8_t address_buf[sizeof(struct sockaddr_in6)];

	socklen_t addrlen;
	int socket_id;
	ssize_t rcv_size;
	size_t length;
	uint8_t *address_start;

	char address_string[INET6_ADDRSTRLEN];
	struct sockaddr_in *address_in = (struct sockaddr_in *) address_buf;
	struct sockaddr_in6 *address_in6 = (struct sockaddr_in6 *) address_buf;
	struct sockaddr *address = (struct sockaddr *) address_buf;

	int rc;

	if (type == SOCK_STREAM) {
		/* Accept a socket if a stream socket is used */
		addrlen = sizeof(address_buf);
            	socket_id = accept(listening_id, (void *) address_buf, &addrlen);
		if (socket_id <= 0) {
			socket_print_error(stderr, socket_id, "Socket accept: ", "\n");
		} else {
			if (verbose)
				printf("Socket %d accepted\n", socket_id);
		}

		assert((size_t) addrlen <= sizeof(address_buf));
	} else {
		socket_id = listening_id;
	}

	/* if the datagram socket is used or the stream socked was accepted */
	if (socket_id > 0) {

		/* Receive a message to echo */
		rcv_size = recvfrom(socket_id, data, size, 0, address,
		    &addrlen);
		if (rcv_size < 0) {
			socket_print_error(stderr, rcv_size, "Socket receive: ", "\n");
		} else {
			length = (size_t) rcv_size;
			if (verbose) {
				/* Print the header */

				/* Get the source port and prepare the address buffer */
				address_start = NULL;
				switch (address->sa_family) {
				case AF_INET:
					port = ntohs(address_in->sin_port);
					address_start = (uint8_t *) &address_in->sin_addr.s_addr;
					break;
				case AF_INET6:
					port = ntohs(address_in6->sin6_port);
					address_start = (uint8_t *) &address_in6->sin6_addr.s6_addr;
					break;
				default:
					fprintf(stderr, "Address family %u (%#x) is not supported.\n",
					    address->sa_family, address->sa_family);
				}

				/* Parse source address */
				if (address_start) {
					rc = inet_ntop(address->sa_family, address_start, address_string, sizeof(address_string));
					if (rc != EOK) {
						fprintf(stderr, "Received address error %d\n", rc);
					} else {
						data[length] = '\0';
						printf("Socket %d received %zu bytes from %s:%d\n%s\n",
						    socket_id, length, address_string, port, data);
					}
				}
			}

			/* Answer the request either with the static reply or the original data */
			rc = sendto(socket_id, reply ? reply : data, reply ? reply_length : length, 0, address, addrlen);
			if (rc != EOK)
				socket_print_error(stderr, rc, "Socket send: ", "\n");
		}

		/* Close accepted stream socket */
		if (type == SOCK_STREAM) {
			rc = closesocket(socket_id);
			if (rc != EOK)
				socket_print_error(stderr, rc, "Close socket: ", "\n");
		}

	}

	return EOK;
}


int main(int argc, char *argv[])
{
	struct sockaddr *address;;
	struct sockaddr_in address_in;
	struct sockaddr_in6 address_in6;
	socklen_t addrlen;

	int listening_id;
	int index;
	int rc;

	/* Parse command line arguments */
	for (index = 1; index < argc; ++index) {
		if (argv[index][0] == '-') {
			rc = netecho_parse_option(argc, argv, &index);
			if (rc != EOK)
				return rc;
		} else {
			echo_print_help();
			return EINVAL;
		}
	}

	/* Check buffer size */
	if (size <= 0) {
		fprintf(stderr, "Receive size too small (%zu). Using 1024 bytes instead.\n", size);
		size = 1024;
	}

	/* size plus the terminating null character. */
	data = (char *) malloc(size + 1);
	if (!data) {
		fprintf(stderr, "Failed to allocate receive buffer.\n");
		return ENOMEM;
	}

	/* Set the reply size if set */
	reply_length = reply ? str_length(reply) : 0;

	/* Prepare the address buffer */
	switch (family) {
	case PF_INET:
		address_in.sin_family = AF_INET;
		address_in.sin_port = htons(port);
		address = (struct sockaddr *) &address_in;
		addrlen = sizeof(address_in);
		break;
	case PF_INET6:
		address_in6.sin6_family = AF_INET6;
		address_in6.sin6_port = htons(port);
		address = (struct sockaddr *) &address_in6;
		addrlen = sizeof(address_in6);
		break;
	default:
		fprintf(stderr, "Protocol family is not supported\n");
		return EAFNOSUPPORT;
	}

	/* Get a listening socket */
	listening_id = socket(family, type, 0);
	if (listening_id < 0) {
		socket_print_error(stderr, listening_id, "Socket create: ", "\n");
		return listening_id;
	}

	/* if the stream socket is used */
	if (type == SOCK_STREAM) {
		/* Check backlog size */
		if (backlog <= 0) {
			fprintf(stderr, "Accepted sockets queue size too small (%zu). Using 3 instead.\n", size);
			backlog = 3;
		}

		/* Set the backlog */
		rc = listen(listening_id, backlog);
		if (rc != EOK) {
			socket_print_error(stderr, rc, "Socket listen: ", "\n");
			return rc;
		}
	}

	/* Bind the listening socket */
	rc = bind(listening_id, address, addrlen);
	if (rc != EOK) {
		socket_print_error(stderr, rc, "Socket bind: ", "\n");
		return rc;
	}

	if (verbose)
		printf("Socket %d listenning at %d\n", listening_id, port);

	/*
	 * do count times
	 * or indefinitely if set to a negative value
	 */
	while (count) {
		rc = netecho_socket_process_message(listening_id);
		if (rc != EOK)
			break;

		/* Decrease count if positive */
		if (count > 0) {
			count--;
			if (verbose)
				printf("Waiting for next %d message(s)\n", count);
		}
	}

	if (verbose)
		printf("Closing the socket\n");

	/* Close listenning socket */
	rc = closesocket(listening_id);
	if (rc != EOK) {
		socket_print_error(stderr, rc, "Close socket: ", "\n");
		return rc;
	}

	if (verbose)
		printf("Exiting\n");

	return EOK;
}

/** @}
 */