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
33 #include <arpa/inet.h>
34 #include <netinet/in.h>
35 #include <sys/types.h>
36 #include <sys/socket.h>
37
38 #include <err.h>
39 #include <errno.h>
40 #include <fcntl.h>
41 #include <stdio.h>
42 #include <stdbool.h>
43 #include <stdlib.h>
44 #include <string.h>
45 #include <unistd.h>
46
47 /*
48 * Sends a single UDP packet to the provided address, with SO_DONTROUTE set
49 * I couldn't find a way to do this with builtin utilities like nc(1)
50 */
51 int
main(int argc,char ** argv)52 main(int argc, char **argv)
53 {
54 struct sockaddr_storage dst;
55 int s, t;
56 int opt;
57 int ret;
58 ssize_t len;
59 const char* sendbuf = "Hello, World!";
60 const size_t buflen = 80;
61 char recvbuf[buflen];
62 bool v6 = false;
63 const char *addr, *tapdev;
64 const uint16_t port = 46120;
65
66 bzero(&dst, sizeof(dst));
67 if (argc < 3 || argc > 4) {
68 fprintf(stderr, "Usage: %s [-6] ip_address tapdev\n", argv[0]);
69 exit(2);
70 }
71
72 if (strcmp("-6", argv[1]) == 0) {
73 v6 = true;
74 addr = argv[2];
75 tapdev = argv[3];
76 } else {
77 addr = argv[1];
78 tapdev = argv[2];
79 }
80
81 t = open(tapdev, O_RDWR | O_NONBLOCK);
82 if (t < 0)
83 err(EXIT_FAILURE, "open");
84
85 if (v6)
86 s = socket(PF_INET6, SOCK_DGRAM, 0);
87 else
88 s = socket(PF_INET, SOCK_DGRAM, 0);
89 if (s < 0)
90 err(EXIT_FAILURE, "socket");
91 opt = 1;
92
93 ret = setsockopt(s, SOL_SOCKET, SO_DONTROUTE, &opt, sizeof(opt));
94 if (ret == -1)
95 err(EXIT_FAILURE, "setsockopt(SO_DONTROUTE)");
96
97 if (v6) {
98 struct sockaddr_in6 *dst6 = ((struct sockaddr_in6*)&dst);
99
100 dst.ss_len = sizeof(struct sockaddr_in6);
101 dst.ss_family = AF_INET6;
102 dst6->sin6_port = htons(port);
103 ret = inet_pton(AF_INET6, addr, &dst6->sin6_addr);
104 } else {
105 struct sockaddr_in *dst4 = ((struct sockaddr_in*)&dst);
106
107 dst.ss_len = sizeof(struct sockaddr_in);
108 dst.ss_family = AF_INET;
109 dst4->sin_port = htons(port);
110 ret = inet_pton(AF_INET, addr, &dst4->sin_addr);
111 }
112 if (ret != 1)
113 err(EXIT_FAILURE, "inet_pton returned %d", ret);
114
115 ret = sendto(s, sendbuf, strlen(sendbuf), 0, (struct sockaddr*)&dst,
116 dst.ss_len);
117 if (ret == -1)
118 err(EXIT_FAILURE, "sendto");
119
120 /* Verify that the packet went to the desired tap device */
121
122 len = read(t, recvbuf, buflen);
123 if (len == 0)
124 errx(EXIT_FAILURE, "read returned EOF");
125 else if (len < 0 && errno == EAGAIN)
126 errx(EXIT_FAILURE, "Did not receive any packets");
127 else if (len < 0)
128 err(EXIT_FAILURE, "read");
129
130 /*
131 * If read returned anything at all, consider it a success. The packet
132 * should be an Ethernet frame containing an ARP request for
133 * ip_address. We won't bother to decode it
134 */
135 return (0);
136 }
137