/*
* Copyright (c) 2014 Spectra Logic Corporation
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions, and the following disclaimer,
* without modification.
* 2. Redistributions in binary form must reproduce at minimum a disclaimer
* substantially similar to the "NO WARRANTY" disclaimer below
* ("Disclaimer") and any redistribution must be conditioned upon
* including a substantially similar Disclaimer requirement for further
* binary redistribution.
*
* NO WARRANTY
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGES.
*
* Authors: Alan Somers (Spectra Logic Corporation)
*/
#include <arpa/inet.h>
#include <netinet/in.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
/*
* Sends a single UDP packet to the provided address, with SO_DONTROUTE set
* I couldn't find a way to do this with builtin utilities like nc(1)
*/
int
main(int argc, char **argv)
{
struct sockaddr_storage dst;
int s, t;
int opt;
int ret;
ssize_t len;
const char* sendbuf = "Hello, World!";
const size_t buflen = 80;
char recvbuf[buflen];
bool v6 = false;
const char *addr, *tapdev;
const uint16_t port = 46120;
bzero(&dst, sizeof(dst));
if (argc < 3 || argc > 4) {
fprintf(stderr, "Usage: %s [-6] ip_address tapdev\n", argv[0]);
exit(2);
}
if (strcmp("-6", argv[1]) == 0) {
v6 = true;
addr = argv[2];
tapdev = argv[3];
} else {
addr = argv[1];
tapdev = argv[2];
}
t = open(tapdev, O_RDWR | O_NONBLOCK);
if (t < 0)
err(EXIT_FAILURE, "open");
if (v6)
s = socket(PF_INET6, SOCK_DGRAM, 0);
else
s = socket(PF_INET, SOCK_DGRAM, 0);
if (s < 0)
err(EXIT_FAILURE, "socket");
opt = 1;
ret = setsockopt(s, SOL_SOCKET, SO_DONTROUTE, &opt, sizeof(opt));
if (ret == -1)
err(EXIT_FAILURE, "setsockopt(SO_DONTROUTE)");
if (v6) {
struct sockaddr_in6 *dst6 = ((struct sockaddr_in6*)&dst);
dst.ss_len = sizeof(struct sockaddr_in6);
dst.ss_family = AF_INET6;
dst6->sin6_port = htons(port);
ret = inet_pton(AF_INET6, addr, &dst6->sin6_addr);
} else {
struct sockaddr_in *dst4 = ((struct sockaddr_in*)&dst);
dst.ss_len = sizeof(struct sockaddr_in);
dst.ss_family = AF_INET;
dst4->sin_port = htons(port);
ret = inet_pton(AF_INET, addr, &dst4->sin_addr);
}
if (ret != 1)
err(EXIT_FAILURE, "inet_pton returned %d", ret);
ret = sendto(s, sendbuf, strlen(sendbuf), 0, (struct sockaddr*)&dst,
dst.ss_len);
if (ret == -1)
err(EXIT_FAILURE, "sendto");
/* Verify that the packet went to the desired tap device */
len = read(t, recvbuf, buflen);
if (len == 0)
errx(EXIT_FAILURE, "read returned EOF");
else if (len < 0 && errno == EAGAIN)
errx(EXIT_FAILURE, "Did not receive any packets");
else if (len < 0)
err(EXIT_FAILURE, "read");
/*
* If read returned anything at all, consider it a success. The packet
* should be an Ethernet frame containing an ARP request for
* ip_address. We won't bother to decode it
*/
return (0);
}
