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/* $NetBSD: natt_terminator.c,v 1.2 2018/11/22 04:51:41 knakahara Exp $ */
/*-
* Copyright (c) 2017 Internet Initiative Japan Inc.
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <netinet/udp.h>
#include <stdio.h>
#include <err.h>
#include <netdb.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
static void
usage(void)
{
const char *prog = "natt_terminator";
fprintf(stderr, "Usage: %s [-46] <addr> <port>\n", prog);
}
int
main(int argc, char **argv)
{
struct addrinfo hints;
struct addrinfo *res;
int s, e;
const char *addr, *port;
int option;
int c, family = AF_INET;
while ((c = getopt(argc, argv, "46")) != -1) {
switch (c) {
case '4':
family = AF_INET;
break;
case '6':
family = AF_INET6;
break;
default:
usage();
return 1;
}
}
argc -= optind;
argv += optind;
if (argc != 2) {
usage();
return 1;
}
addr = argv[0];
port = argv[1];
memset(&hints, 0, sizeof(hints));
hints.ai_family = family;
hints.ai_socktype = SOCK_DGRAM;
hints.ai_protocol = IPPROTO_UDP;
hints.ai_flags = 0;
e = getaddrinfo(addr, port, &hints, &res);
if (e != 0)
errx(EXIT_FAILURE, "getaddrinfo failed: %s", gai_strerror(e));
s = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
if (s == -1)
err(EXIT_FAILURE, "socket");
/*
* Set the option to tell the kernel that the socket can handle
* UDP-encapsulated ESP packets for NAT-T.
*/
option = UDP_ENCAP_ESPINUDP;
e = setsockopt(s, IPPROTO_UDP, UDP_ENCAP, &option, sizeof(option));
if (e == -1)
err(EXIT_FAILURE, "setsockopt(UDP_ENCAP)");
e = bind(s, res->ai_addr, res->ai_addrlen);
if (e == -1)
err(EXIT_FAILURE, "bind");
/* Receiving a packet make the NAPT create a mapping. */
{
char buf[64];
struct sockaddr_storage z;
socklen_t len = sizeof(z);
e = recvfrom(s, buf, 64, MSG_PEEK,
(struct sockaddr *)&z, &len);
if (e == -1)
err(EXIT_FAILURE, "recvfrom");
}
/*
* Keep the socket in the kernel to handle UDP-encapsulated ESP packets.
*/
pause();
close(s);
return 0;
}
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