1 /* $NetBSD: natt_terminator.c,v 1.1 2017/10/30 15:59:23 ozaki-r Exp $ */ 2 3 /*- 4 * Copyright (c) 2017 Internet Initiative Japan Inc. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 #include <sys/types.h> 30 #include <sys/socket.h> 31 #include <sys/wait.h> 32 #include <sys/time.h> 33 34 #include <netinet/in.h> 35 #include <netinet/udp.h> 36 37 #include <stdio.h> 38 #include <err.h> 39 #include <netdb.h> 40 #include <string.h> 41 #include <stdlib.h> 42 #include <unistd.h> 43 44 int 45 main(int argc, char **argv) 46 { 47 struct addrinfo hints; 48 struct addrinfo *res; 49 int s, e; 50 const char *addr, *port; 51 int option; 52 53 if (argc != 3) { 54 fprintf(stderr, "Usage: %s <addr> <port>\n", argv[0]); 55 return 1; 56 } 57 58 addr = argv[1]; 59 port = argv[2]; 60 61 memset(&hints, 0, sizeof(hints)); 62 hints.ai_family = AF_INET; 63 hints.ai_socktype = SOCK_DGRAM; 64 hints.ai_protocol = IPPROTO_UDP; 65 hints.ai_flags = 0; 66 67 e = getaddrinfo(addr, port, &hints, &res); 68 if (e != 0) 69 errx(EXIT_FAILURE, "getaddrinfo failed: %s", gai_strerror(e)); 70 71 s = socket(res->ai_family, res->ai_socktype, res->ai_protocol); 72 if (s == -1) 73 err(EXIT_FAILURE, "socket"); 74 75 /* 76 * Set the option to tell the kernel that the socket can handle 77 * UDP-encapsulated ESP packets for NAT-T. 78 */ 79 option = UDP_ENCAP_ESPINUDP; 80 e = setsockopt(s, IPPROTO_UDP, UDP_ENCAP, &option, sizeof(option)); 81 if (e == -1) 82 err(EXIT_FAILURE, "setsockopt(UDP_ENCAP)"); 83 84 e = bind(s, res->ai_addr, res->ai_addrlen); 85 if (e == -1) 86 err(EXIT_FAILURE, "bind"); 87 88 /* Receiving a packet make the NAPT create a mapping. */ 89 { 90 char buf[64]; 91 struct sockaddr_storage z; 92 socklen_t len = sizeof(z); 93 94 e = recvfrom(s, buf, 64, MSG_PEEK, 95 (struct sockaddr *)&z, &len); 96 if (e == -1) 97 err(EXIT_FAILURE, "recvfrom"); 98 } 99 100 /* 101 * Keep the socket in the kernel to handle UDP-encapsulated ESP packets. 102 */ 103 pause(); 104 105 close(s); 106 107 return 0; 108 } 109