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
usage(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
main(int argc,char ** argv)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