1 /* $NetBSD: natt_terminator.c,v 1.2 2018/11/22 04:51:41 knakahara 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 static void 45 usage(void) 46 { 47 const char *prog = "natt_terminator"; 48 49 fprintf(stderr, "Usage: %s [-46] <addr> <port>\n", prog); 50 } 51 52 int 53 main(int argc, char **argv) 54 { 55 struct addrinfo hints; 56 struct addrinfo *res; 57 int s, e; 58 const char *addr, *port; 59 int option; 60 int c, family = AF_INET; 61 62 while ((c = getopt(argc, argv, "46")) != -1) { 63 switch (c) { 64 case '4': 65 family = AF_INET; 66 break; 67 case '6': 68 family = AF_INET6; 69 break; 70 default: 71 usage(); 72 return 1; 73 } 74 } 75 argc -= optind; 76 argv += optind; 77 78 if (argc != 2) { 79 usage(); 80 return 1; 81 } 82 83 addr = argv[0]; 84 port = argv[1]; 85 86 memset(&hints, 0, sizeof(hints)); 87 hints.ai_family = family; 88 hints.ai_socktype = SOCK_DGRAM; 89 hints.ai_protocol = IPPROTO_UDP; 90 hints.ai_flags = 0; 91 92 e = getaddrinfo(addr, port, &hints, &res); 93 if (e != 0) 94 errx(EXIT_FAILURE, "getaddrinfo failed: %s", gai_strerror(e)); 95 96 s = socket(res->ai_family, res->ai_socktype, res->ai_protocol); 97 if (s == -1) 98 err(EXIT_FAILURE, "socket"); 99 100 /* 101 * Set the option to tell the kernel that the socket can handle 102 * UDP-encapsulated ESP packets for NAT-T. 103 */ 104 option = UDP_ENCAP_ESPINUDP; 105 e = setsockopt(s, IPPROTO_UDP, UDP_ENCAP, &option, sizeof(option)); 106 if (e == -1) 107 err(EXIT_FAILURE, "setsockopt(UDP_ENCAP)"); 108 109 e = bind(s, res->ai_addr, res->ai_addrlen); 110 if (e == -1) 111 err(EXIT_FAILURE, "bind"); 112 113 /* Receiving a packet make the NAPT create a mapping. */ 114 { 115 char buf[64]; 116 struct sockaddr_storage z; 117 socklen_t len = sizeof(z); 118 119 e = recvfrom(s, buf, 64, MSG_PEEK, 120 (struct sockaddr *)&z, &len); 121 if (e == -1) 122 err(EXIT_FAILURE, "recvfrom"); 123 } 124 125 /* 126 * Keep the socket in the kernel to handle UDP-encapsulated ESP packets. 127 */ 128 pause(); 129 130 close(s); 131 132 return 0; 133 } 134