xref: /freebsd-10.0-release/usr.sbin/tcpdrop/tcpdrop.c

/* $OpenBSD: tcpdrop.c,v 1.4 2004/05/22 23:55:22 deraadt Exp $ */

/*-
 * Copyright (c) 2004 Markus Friedl <markus@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD: head/usr.sbin/tcpdrop/tcpdrop.c 173223 2007-10-31 13:49:20Z ru $");

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <netinet/in.h>
#include <netinet/tcp_var.h>

#include <err.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/*
 * Drop a tcp connection.
 */
int
main(int argc, char *argv[])
{
	struct addrinfo hints, *ail, *aif, *laddr, *faddr;
	/* addrs[0] is a foreign socket, addrs[1] is a local one. */
	struct sockaddr_storage addrs[2];
	int mib[] = { CTL_NET, PF_INET, IPPROTO_TCP, TCPCTL_DROP };
	int gaierr, rval = 0;
	char fhbuf[NI_MAXHOST], fsbuf[NI_MAXSERV], lhbuf[NI_MAXHOST],
	    lsbuf[NI_MAXSERV];

	if (argc != 5) {
		fprintf(stderr, "usage: tcpdrop laddr lport faddr fport\n");
		exit(1);
	}
	memset(&hints, 0, sizeof(hints));
	hints.ai_family = AF_UNSPEC;
	hints.ai_socktype = SOCK_STREAM;
	if ((gaierr = getaddrinfo(argv[1], argv[2], &hints, &laddr)) != 0)
		errx(1, "%s port %s: %s", argv[1], argv[2],
		    gai_strerror(gaierr));
	if ((gaierr = getaddrinfo(argv[3], argv[4], &hints, &faddr)) != 0) {
		freeaddrinfo(laddr);
		errx(1, "%s port %s: %s", argv[3], argv[4],
		    gai_strerror(gaierr));
	}
	for (ail = laddr; ail; ail = ail->ai_next) {
		for (aif = faddr; aif; aif = aif->ai_next) {
			if (ail->ai_family != aif->ai_family)
				continue;
			memcpy(&addrs[0], aif->ai_addr, aif->ai_addrlen);
			memcpy(&addrs[1], ail->ai_addr, ail->ai_addrlen);
			if (getnameinfo(aif->ai_addr, aif->ai_addrlen,
			    fhbuf, sizeof(fhbuf),
			    fsbuf, sizeof(fsbuf),
			    NI_NUMERICHOST | NI_NUMERICSERV) == -1)
				err(1, "getnameinfo");
			if (getnameinfo(ail->ai_addr, ail->ai_addrlen,
			    lhbuf, sizeof(lhbuf),
			    lsbuf, sizeof(lsbuf),
			    NI_NUMERICHOST | NI_NUMERICSERV) == -1)
				err(1, "getnameinfo");
			if (sysctl(mib, sizeof (mib) / sizeof (int), NULL,
			    NULL, &addrs, sizeof(addrs)) == -1) {
				rval = 1;
				warn("%s %s %s %s", lhbuf, lsbuf, fhbuf, fsbuf);
			} else
				printf("%s %s %s %s: dropped\n",
				    lhbuf, lsbuf, fhbuf, fsbuf);
		}
	}
	freeaddrinfo(laddr);
	freeaddrinfo(faddr);
	exit(rval);
}