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/* $OpenBSD: tcpdrop.c,v 1.20 2021/07/12 15:09:21 beck 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/socket.h>
#include <sys/sysctl.h>
#include <sys/queue.h>
#include <sys/timeout.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <netinet/tcp_timer.h>
#include <netinet/tcp_var.h>
#include <err.h>
#include <netdb.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <resolv.h>
__dead void usage(void);
__dead void
usage(void)
{
extern char *__progname;
fprintf(stderr,
"usage: %s local-addr local-port remote-addr remote-port\n",
__progname);
fprintf(stderr,
" %s local-addr:local-port remote-addr:remote-port\n",
__progname);
exit(1);
}
/*
* Drop a tcp connection.
*/
int
main(int argc, char **argv)
{
int mib[] = { CTL_NET, PF_INET, IPPROTO_TCP, TCPCTL_DROP };
struct addrinfo hints, *ail, *aif, *laddr, *faddr;
char fhbuf[NI_MAXHOST], fsbuf[NI_MAXSERV];
char lhbuf[NI_MAXHOST], lsbuf[NI_MAXSERV];
char *laddr1, *addr1, *port1, *faddr2, *addr2, *port2;
struct tcp_ident_mapping tir;
int gaierr, rval = 0;
if (unveil(_PATH_HOSTS, "r") == -1)
err(1, "unveil %s", _PATH_HOSTS);
if (unveil(_PATH_RESCONF, "r") == -1)
err(1, "unveil %s", _PATH_RESCONF);
if (unveil(NULL, NULL) == -1)
err(1, "unveil");
memset(&hints, 0, sizeof(hints));
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
if (argc == 3) {
laddr1 = addr1 = strdup(argv[1]);
if (!addr1)
err(1, "strdup");
port1 = strrchr(addr1, ':');
if (port1)
*port1++ = '\0';
else
usage();
faddr2 = addr2 = strdup(argv[2]);
if (!addr2)
err(1, "strdup");
port2 = strrchr(addr2, ':');
if (port2)
*port2++ = '\0';
else
usage();
} else if (argc == 5) {
laddr1 = addr1 = argv[1];
port1 = argv[2];
faddr2 = addr2 = argv[3];
port2 = argv[4];
} else
usage();
if (addr1[0] == '[' && addr1[strlen(addr1) - 1] == ']') {
laddr1 = strdup(addr1);
if (!laddr1)
err(1, "strdup");
laddr1[strlen(laddr1) - 1] = '\0';
laddr1++;
}
if (addr2[0] == '[' && addr2[strlen(addr2) - 1] == ']') {
faddr2 = strdup(addr2);
if (!faddr2)
err(1, "strdup");
faddr2[strlen(faddr2) - 1] = '\0';
faddr2++;
}
if ((gaierr = getaddrinfo(laddr1, port1, &hints, &laddr)) != 0)
errx(1, "%s port %s: %s", addr1, port1,
gai_strerror(gaierr));
if ((gaierr = getaddrinfo(faddr2, port2, &hints, &faddr)) != 0)
errx(1, "%s port %s: %s", addr2, port2,
gai_strerror(gaierr));
rval = 1;
for (ail = laddr; ail; ail = ail->ai_next) {
for (aif = faddr; aif; aif = aif->ai_next) {
if (ail->ai_family != aif->ai_family)
continue;
rval = 0;
memset(&tir, 0, sizeof(tir));
memcpy(&tir.faddr, aif->ai_addr, aif->ai_addrlen);
memcpy(&tir.laddr, ail->ai_addr, ail->ai_addrlen);
if ((gaierr = getnameinfo(aif->ai_addr, aif->ai_addrlen,
fhbuf, sizeof(fhbuf), fsbuf, sizeof(fsbuf),
NI_NUMERICHOST | NI_NUMERICSERV)) != 0)
errx(1, "getnameinfo: %s", gai_strerror(gaierr));
if ((gaierr = getnameinfo(ail->ai_addr, ail->ai_addrlen,
lhbuf, sizeof(lhbuf), lsbuf, sizeof(lsbuf),
NI_NUMERICHOST | NI_NUMERICSERV)) != 0)
errx(1, "getnameinfo: %s", gai_strerror(gaierr));
if (sysctl(mib, sizeof (mib) / sizeof (int), NULL,
NULL, &tir, sizeof(tir)) == -1) {
rval = 1;
warn("%s %s %s %s", lhbuf, lsbuf, fhbuf, fsbuf);
} else {
if (aif->ai_family == PF_INET6)
printf("[%s]:%s [%s]:%s dropped\n",
lhbuf, lsbuf, fhbuf, fsbuf);
else
printf("%s:%s %s:%s dropped\n",
lhbuf, lsbuf, fhbuf, fsbuf);
}
}
}
freeaddrinfo(laddr);
freeaddrinfo(faddr);
exit(rval);
}
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