/*
    sptps_test.c -- Simple Peer-to-Peer Security test program
    Copyright (C) 2011-2014 Guus Sliepen <guus@tinc-vpn.org>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License along
    with this program; if not, write to the Free Software Foundation, Inc.,
    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#include "system.h"

#ifdef HAVE_LINUX
#include <linux/if_tun.h>
#endif

#include <getopt.h>

#include "crypto.h"
#include "ecdsa.h"
#include "sptps.h"
#include "utils.h"

// Symbols necessary to link with logger.o
bool send_request(void *c, const char *msg, ...) { return false; }
struct list_t *connection_list = NULL;
bool send_meta(void *c, const char *msg , int len) { return false; }
char *logfilename = NULL;
bool do_detach = false;
struct timeval now;

static bool special;
static bool verbose;
static bool readonly;
static bool writeonly;
static int in = 0;
static int out = 1;

static bool send_data(void *handle, uint8_t type, const void *data, size_t len) {
	char hex[len * 2 + 1];
	UNUSED(type);
	bin2hex(data, hex, len);
	if(verbose)
		fprintf(stderr, "Sending %d bytes of data:\n%s\n", (int)len, hex);
	const int *sock = handle;
	if(send(*sock, data, len, 0) != len)
		return false;
	return true;
}

static bool receive_record(void *handle, uint8_t type, const void *data, uint16_t len) {
	UNUSED(handle);
	if(verbose)
		fprintf(stderr, "Received type %d record of %hu bytes:\n", type, len);
	if(!writeonly)
		write(out, data, len);
	return true;
}

static struct option const long_options[] = {
	{"datagram", no_argument, NULL, 'd'},
	{"quit", no_argument, NULL, 'q'},
	{"readonly", no_argument, NULL, 'r'},
	{"writeonly", no_argument, NULL, 'w'},
	{"packet-loss", required_argument, NULL, 'L'},
	{"replay-window", required_argument, NULL, 'W'},
	{"special", no_argument, NULL, 's'},
	{"verbose", required_argument, NULL, 'v'},
	{"help", no_argument, NULL, 1},
	{NULL, 0, NULL, 0}
};

static const char *program_name;

static void usage() {
	fprintf(stderr, "Usage: %s [options] my_ed25519_key_file his_ed25519_key_file [host] port\n\n", program_name);
	fprintf(stderr, "Valid options are:\n"
			"  -d, --datagram          Enable datagram mode.\n"
			"  -q, --quit              Quit when EOF occurs on stdin.\n"
			"  -r, --readonly          Only send data from the socket to stdout.\n"
#ifdef HAVE_LINUX
			"  -t, --tun               Use a tun device instead of stdio.\n"
#endif
			"  -w, --writeonly         Only send data from stdin to the socket.\n"
			"  -L, --packet-loss RATE  Fake packet loss of RATE percent.\n"
			"  -R, --replay-window N   Set replay window to N bytes.\n"
			"  -s, --special           Enable special handling of lines starting with #, ^ and $.\n"
			"  -v, --verbose           Display debug messages.\n"
			"\n");
	fprintf(stderr, "Report bugs to tinc@tinc-vpn.org.\n");
}

int main(int argc, char *argv[]) {
	program_name = argv[0];
	bool initiator = false;
	bool datagram = false;
#ifdef HAVE_LINUX
	bool tun = false;
#endif
	int packetloss = 0;
	int r;
	int option_index = 0;
	ecdsa_t *mykey = NULL, *hiskey = NULL;
	bool quit = false;

	while((r = getopt_long(argc, argv, "dqrstwL:W:v", long_options, &option_index)) != EOF) {
		switch (r) {
			case 0:   /* long option */
				break;

			case 'd': /* datagram mode */
				datagram = true;
				break;

			case 'q': /* close connection on EOF from stdin */
				quit = true;
				break;

			case 'r': /* read only */
				readonly = true;
				break;

			case 't': /* read only */
#ifdef HAVE_LINUX
				tun = true;
#else
				fprintf(stderr, "--tun is only supported on Linux.\n");
				usage();
				return 1;
#endif
				break;

			case 'w': /* write only */
				writeonly = true;
				break;

			case 'L': /* packet loss rate */
				packetloss = atoi(optarg);
				break;

			case 'W': /* replay window size */
				sptps_replaywin = atoi(optarg);
				break;

			case 'v': /* be verbose */
				verbose = true;
				break;

			case 's': /* special character handling */
				special = true;
				break;

			case '?': /* wrong options */
				usage();
				return 1;

			case 1: /* help */
				usage();
				return 0;

			default:
				break;
		}
	}

	argc -= optind - 1;
	argv += optind - 1;

	if(argc < 4 || argc > 5) {
		fprintf(stderr, "Wrong number of arguments.\n");
		usage();
		return 1;
	}

	if(argc > 4)
		initiator = true;

	srand(time(NULL));

#ifdef HAVE_LINUX
	if(tun) {
		in = out = open("/dev/net/tun", O_RDWR | O_NONBLOCK);
		if(in < 0) {
			fprintf(stderr, "Could not open tun device: %s\n", strerror(errno));
			return 1;
		}
		struct ifreq ifr = {
			.ifr_flags = IFF_TUN
		};
		if(ioctl(in, TUNSETIFF, &ifr)) {
			fprintf(stderr, "Could not configure tun interface: %s\n", strerror(errno));
			return 1;
		}
		ifr.ifr_name[IFNAMSIZ - 1] = 0;
		fprintf(stderr, "Using tun interface %s\n", ifr.ifr_name);
	}
#endif

#ifdef HAVE_MINGW
	static struct WSAData wsa_state;
	if(WSAStartup(MAKEWORD(2, 2), &wsa_state))
		return 1;
#endif

	struct addrinfo *ai, hint;
	memset(&hint, 0, sizeof hint);

	hint.ai_family = AF_UNSPEC;
	hint.ai_socktype = datagram ? SOCK_DGRAM : SOCK_STREAM;
	hint.ai_protocol = datagram ? IPPROTO_UDP : IPPROTO_TCP;
	hint.ai_flags = initiator ? 0 : AI_PASSIVE;

	if(getaddrinfo(initiator ? argv[3] : NULL, initiator ? argv[4] : argv[3], &hint, &ai) || !ai) {
		fprintf(stderr, "getaddrinfo() failed: %s\n", sockstrerror(sockerrno));
		return 1;
	}

	int sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
	if(sock < 0) {
		fprintf(stderr, "Could not create socket: %s\n", sockstrerror(sockerrno));
		return 1;
	}

	int one = 1;
	setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&one, sizeof one);

	if(initiator) {
		if(connect(sock, ai->ai_addr, ai->ai_addrlen)) {
			fprintf(stderr, "Could not connect to peer: %s\n", sockstrerror(sockerrno));
			return 1;
		}
		fprintf(stderr, "Connected\n");
	} else {
		if(bind(sock, ai->ai_addr, ai->ai_addrlen)) {
			fprintf(stderr, "Could not bind socket: %s\n", sockstrerror(sockerrno));
			return 1;
		}

		if(!datagram) {
			if(listen(sock, 1)) {
				fprintf(stderr, "Could not listen on socket: %s\n", sockstrerror(sockerrno));
				return 1;
			}
			fprintf(stderr, "Listening...\n");

			sock = accept(sock, NULL, NULL);
			if(sock < 0) {
				fprintf(stderr, "Could not accept connection: %s\n", sockstrerror(sockerrno));
				return 1;
			}
		} else {
			fprintf(stderr, "Listening...\n");

			char buf[65536];
			struct sockaddr addr;
			socklen_t addrlen = sizeof addr;

			if(recvfrom(sock, buf, sizeof buf, MSG_PEEK, &addr, &addrlen) <= 0) {
				fprintf(stderr, "Could not read from socket: %s\n", sockstrerror(sockerrno));
				return 1;
			}

			if(connect(sock, &addr, addrlen)) {
				fprintf(stderr, "Could not accept connection: %s\n", sockstrerror(sockerrno));
				return 1;
			}
		}

		fprintf(stderr, "Connected\n");
	}

	crypto_init();

	FILE *fp = fopen(argv[1], "r");
	if(!fp) {
		fprintf(stderr, "Could not open %s: %s\n", argv[1], strerror(errno));
		return 1;
	}
	if(!(mykey = ecdsa_read_pem_private_key(fp)))
		return 1;
	fclose(fp);

	fp = fopen(argv[2], "r");
	if(!fp) {
		fprintf(stderr, "Could not open %s: %s\n", argv[2], strerror(errno));
		return 1;
	}
	if(!(hiskey = ecdsa_read_pem_public_key(fp)))
		return 1;
	fclose(fp);

	if(verbose)
		fprintf(stderr, "Keys loaded\n");

	sptps_t s;
	if(!sptps_start(&s, &sock, initiator, datagram, mykey, hiskey, "sptps_test", 10, send_data, receive_record))
		return 1;

	while(true) {
		if(writeonly && readonly)
			break;

		char buf[65535] = "";

		fd_set fds;
		FD_ZERO(&fds);
#ifndef HAVE_MINGW
		if(!readonly && s.instate)
			FD_SET(in, &fds);
#endif
		FD_SET(sock, &fds);
		if(select(sock + 1, &fds, NULL, NULL, NULL) <= 0)
			return 1;

		if(FD_ISSET(in, &fds)) {
			ssize_t len = read(in, buf, sizeof buf);
			if(len < 0) {
				fprintf(stderr, "Could not read from stdin: %s\n", strerror(errno));
				return 1;
			}
			if(len == 0) {
				if(quit)
					break;
				readonly = true;
				continue;
			}
			if(special && buf[0] == '#')
				s.outseqno = atoi(buf + 1);
			if(special && buf[0] == '^')
				sptps_send_record(&s, SPTPS_HANDSHAKE, NULL, 0);
			else if(special && buf[0] == '$') {
				sptps_force_kex(&s);
				if(len > 1)
					sptps_send_record(&s, 0, buf, len);
			} else
			if(!sptps_send_record(&s, buf[0] == '!' ? 1 : 0, buf, (len == 1 && buf[0] == '\n') ? 0 : buf[0] == '*' ? sizeof buf : len))
				return 1;
		}

		if(FD_ISSET(sock, &fds)) {
			ssize_t len = recv(sock, buf, sizeof buf, 0);
			if(len < 0) {
				fprintf(stderr, "Could not read from socket: %s\n", sockstrerror(sockerrno));
				return 1;
			}
			if(len == 0) {
				fprintf(stderr, "Connection terminated by peer.\n");
				break;
			}
			if(verbose) {
				char hex[len * 2 + 1];
				bin2hex(buf, hex, len);
				fprintf(stderr, "Received %d bytes of data:\n%s\n", (int)len, hex);
			}
			if(packetloss && (rand() % 100) < packetloss) {
				if(verbose)
					fprintf(stderr, "Dropped.\n");
				continue;
			}
			char *bufp = buf;
			while(len) {
				size_t done = sptps_receive_data(&s, bufp, len);
				if(!done) {
					if(!datagram)
						return 1;
				} else {
					break;
				}

				bufp += done;
				len -= done;
			}
		}
	}

	if(!sptps_stop(&s))
		return 1;

	return 0;
}