udp_dontroute.c revision 267186 
1/*
2 *  Copyright (c) 2014 Spectra Logic Corporation
3 *  All rights reserved.
4 *
5 *  Redistribution and use in source and binary forms, with or without
6 *  modification, are permitted provided that the following conditions
7 *  are met:
8 *  1. Redistributions of source code must retain the above copyright
9 *     notice, this list of conditions, and the following disclaimer,
10 *     without modification.
11 *  2. Redistributions in binary form must reproduce at minimum a disclaimer
12 *     substantially similar to the "NO WARRANTY" disclaimer below
13 *     ("Disclaimer") and any redistribution must be conditioned upon
14 *     including a substantially similar Disclaimer requirement for further
15 *     binary redistribution.
16 *
17 *  NO WARRANTY
18 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
21 *  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 *  HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 *  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 *  OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 *  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
26 *  STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
27 *  IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
28 *  POSSIBILITY OF SUCH DAMAGES.
29 *
30 *  Authors: Alan Somers         (Spectra Logic Corporation)
31 *
32 * $FreeBSD: stable/10/tests/sys/netinet/udp_dontroute.c 267186 2014-06-06 20:35:40Z asomers $
33 */
34
35#include <arpa/inet.h>
36#include <netinet/in.h>
37#include <sys/types.h>
38#include <sys/socket.h>
39
40#include <err.h>
41#include <errno.h>
42#include <fcntl.h>
43#include <stdio.h>
44#include <stdlib.h>
45#include <string.h>
46#include <unistd.h>
47
48/*
49 * Sends a single UDP packet to the provided address, with SO_DONTROUTE set
50 * I couldn't find a way to do this with builtin utilities like nc(1)
51 */
52int
53main(int argc, char **argv)
54{
55	struct sockaddr_in dst;
56	int s, t;
57	int opt;
58	int ret;
59	ssize_t len;
60	const char* sendbuf = "Hello, World!";
61	const size_t buflen = 80;
62	char recvbuf[buflen];
63
64	if (argc != 3) {
65		fprintf(stderr, "Usage: %s ip_address tapdev\n", argv[0]);
66		exit(2);
67	}
68
69	t = open(argv[2], O_RDWR | O_NONBLOCK);
70	if (t < 0)
71		err(EXIT_FAILURE, "open");
72
73	s = socket(PF_INET, SOCK_DGRAM, 0);
74	if (s < 0)
75		err(EXIT_FAILURE, "socket");
76	opt = 1;
77
78	ret = setsockopt(s, SOL_SOCKET, SO_DONTROUTE, &opt, sizeof(opt));
79	if (ret == -1)
80		err(EXIT_FAILURE, "setsockopt(SO_DONTROUTE)");
81
82	dst.sin_len = sizeof(dst);
83	dst.sin_family = AF_INET;
84	dst.sin_port = htons(46120);
85	dst.sin_addr.s_addr = inet_addr(argv[1]);
86	if (dst.sin_addr.s_addr == htonl(INADDR_NONE)) {
87		fprintf(stderr, "Invalid address: %s\n", argv[1]);
88		exit(2);
89	}
90	ret = sendto(s, sendbuf, strlen(sendbuf), 0, (struct sockaddr*)&dst,
91	    dst.sin_len);
92	if (ret == -1)
93		err(EXIT_FAILURE, "sendto");
94
95	/* Verify that the packet went to the desired tap device */
96
97	len = read(t, recvbuf, buflen);
98	if (len == 0)
99		errx(EXIT_FAILURE, "read returned EOF");
100	else if (len < 0 && errno == EAGAIN)
101		errx(EXIT_FAILURE, "Did not receive any packets");
102	else if (len < 0)
103		err(EXIT_FAILURE, "read");
104
105	/*
106	 * If read returned anything at all, consider it a success.  The packet
107	 * should be an Ethernet frame containing an ARP request for
108	 * ip_address.  We won't bother to decode it
109	 */
110	return (0);
111}
112