/* $OpenBSD: tcpdrop.c,v 1.4 2004/05/22 23:55:22 deraadt Exp $ */
/*-
* Copyright (c) 2009 Juli Mallett <jmallett@FreeBSD.org>
* 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>
#include <sys/param.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sysctl.h>
#include <netinet/in.h>
#include <netinet/in_pcb.h>
#define TCPSTATES
#include <netinet/tcp_fsm.h>
#include <netinet/tcp_var.h>
#include <err.h>
#include <netdb.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#define TCPDROP_FOREIGN 0
#define TCPDROP_LOCAL 1
struct host_service {
char hs_host[NI_MAXHOST];
char hs_service[NI_MAXSERV];
};
static bool tcpdrop_list_commands = false;
static char *findport(const char *);
static struct xinpgen *getxpcblist(const char *);
static void sockinfo(const struct sockaddr *, struct host_service *);
static bool tcpdrop(const struct sockaddr *, const struct sockaddr *);
static bool tcpdropall(const char *, const char *, int);
static bool tcpdropbyname(const char *, const char *, const char *,
const char *);
static bool tcpdropconn(const struct in_conninfo *);
static void usage(void) __dead2;
/*
* Drop a tcp connection.
*/
int
main(int argc, char *argv[])
{
char stack[TCP_FUNCTION_NAME_LEN_MAX];
char ca_name[TCP_CA_NAME_MAX];
char *lport, *fport;
bool dropall, dropspecific;
int ch, state;
dropall = false;
dropspecific = false;
ca_name[0] = '\0';
stack[0] = '\0';
state = -1;
while ((ch = getopt(argc, argv, "aC:lS:s:")) != -1) {
switch (ch) {
case 'a':
dropall = true;
break;
case 'C':
dropspecific = true;
strlcpy(ca_name, optarg, sizeof(ca_name));
break;
case 'l':
tcpdrop_list_commands = true;
break;
case 'S':
dropspecific = true;
strlcpy(stack, optarg, sizeof(stack));
break;
case 's':
dropspecific = true;
for (state = 0; state < TCP_NSTATES; state++) {
if (strcmp(tcpstates[state], optarg) == 0)
break;
}
break;
default:
usage();
}
}
argc -= optind;
argv += optind;
if (state == TCP_NSTATES ||
state == TCPS_CLOSED ||
state == TCPS_LISTEN)
usage();
if (dropall && dropspecific)
usage();
if (dropall || dropspecific) {
if (argc != 0)
usage();
if (!tcpdropall(ca_name, stack, state))
exit(1);
exit(0);
}
if ((argc != 2 && argc != 4) || tcpdrop_list_commands)
usage();
if (argc == 2) {
lport = findport(argv[0]);
fport = findport(argv[1]);
if (lport == NULL || lport[1] == '\0' || fport == NULL ||
fport[1] == '\0')
usage();
*lport++ = '\0';
*fport++ = '\0';
if (!tcpdropbyname(argv[0], lport, argv[1], fport))
exit(1);
} else if (!tcpdropbyname(argv[0], argv[1], argv[2], argv[3]))
exit(1);
exit(0);
}
static char *
findport(const char *arg)
{
char *dot, *colon;
/* A strrspn() or strrpbrk() would be nice. */
dot = strrchr(arg, '.');
colon = strrchr(arg, ':');
if (dot == NULL)
return (colon);
if (colon == NULL)
return (dot);
if (dot < colon)
return (colon);
else
return (dot);
}
static struct xinpgen *
getxpcblist(const char *name)
{
struct xinpgen *xinp;
size_t len;
int rv;
len = 0;
rv = sysctlbyname(name, NULL, &len, NULL, 0);
if (rv == -1)
err(1, "sysctlbyname %s", name);
if (len == 0)
errx(1, "%s is empty", name);
xinp = malloc(len);
if (xinp == NULL)
errx(1, "malloc failed");
rv = sysctlbyname(name, xinp, &len, NULL, 0);
if (rv == -1)
err(1, "sysctlbyname %s", name);
return (xinp);
}
static void
sockinfo(const struct sockaddr *sa, struct host_service *hs)
{
static const int flags = NI_NUMERICHOST | NI_NUMERICSERV;
int rv;
rv = getnameinfo(sa, sa->sa_len, hs->hs_host, sizeof hs->hs_host,
hs->hs_service, sizeof hs->hs_service, flags);
if (rv == -1)
err(1, "getnameinfo");
}
static bool
tcpdrop(const struct sockaddr *lsa, const struct sockaddr *fsa)
{
struct host_service local, foreign;
struct sockaddr_storage addrs[2];
int rv;
memcpy(&addrs[TCPDROP_FOREIGN], fsa, fsa->sa_len);
memcpy(&addrs[TCPDROP_LOCAL], lsa, lsa->sa_len);
sockinfo(lsa, &local);
sockinfo(fsa, &foreign);
if (tcpdrop_list_commands) {
printf("tcpdrop %s %s %s %s\n", local.hs_host, local.hs_service,
foreign.hs_host, foreign.hs_service);
return (true);
}
rv = sysctlbyname("net.inet.tcp.drop", NULL, NULL, &addrs,
sizeof addrs);
if (rv == -1) {
warn("%s %s %s %s", local.hs_host, local.hs_service,
foreign.hs_host, foreign.hs_service);
return (false);
}
printf("%s %s %s %s: dropped\n", local.hs_host, local.hs_service,
foreign.hs_host, foreign.hs_service);
return (true);
}
static bool
tcpdropall(const char *ca_name, const char *stack, int state)
{
struct xinpgen *head, *xinp;
struct xtcpcb *xtp;
struct xinpcb *xip;
bool ok;
ok = true;
head = getxpcblist("net.inet.tcp.pcblist");
#define XINP_NEXT(xinp) \
((struct xinpgen *)(uintptr_t)((uintptr_t)(xinp) + (xinp)->xig_len))
for (xinp = XINP_NEXT(head); xinp->xig_len > sizeof *xinp;
xinp = XINP_NEXT(xinp)) {
xtp = (struct xtcpcb *)xinp;
xip = &xtp->xt_inp;
/*
* XXX
* Check protocol, support just v4 or v6, etc.
*/
/* Ignore PCBs which were freed during copyout. */
if (xip->inp_gencnt > head->xig_gen)
continue;
/* Skip listening sockets. */
if (xtp->t_state == TCPS_LISTEN)
continue;
/* If requested, skip sockets not having the requested state. */
if ((state != -1) && (xtp->t_state != state))
continue;
/*
* If requested, skip sockets not having the requested
* congestion control algorithm.
*/
if (ca_name[0] != '\0' &&
strncmp(xtp->xt_cc, ca_name, TCP_CA_NAME_MAX))
continue;
/* If requested, skip sockets not having the requested stack. */
if (stack[0] != '\0' &&
strncmp(xtp->xt_stack, stack, TCP_FUNCTION_NAME_LEN_MAX))
continue;
if (!tcpdropconn(&xip->inp_inc))
ok = false;
}
free(head);
return (ok);
}
static bool
tcpdropbyname(const char *lhost, const char *lport, const char *fhost,
const char *fport)
{
static const struct addrinfo hints = {
/*
* Look for TCP streams in all domains.
*/
.ai_family = AF_UNSPEC,
.ai_socktype = SOCK_STREAM,
.ai_protocol = IPPROTO_TCP,
};
struct addrinfo *ail, *local, *aif, *foreign;
int error;
bool ok, infamily;
error = getaddrinfo(lhost, lport, &hints, &local);
if (error != 0)
errx(1, "getaddrinfo: %s port %s: %s", lhost, lport,
gai_strerror(error));
error = getaddrinfo(fhost, fport, &hints, &foreign);
if (error != 0) {
freeaddrinfo(local); /* XXX gratuitous */
errx(1, "getaddrinfo: %s port %s: %s", fhost, fport,
gai_strerror(error));
}
ok = true;
infamily = false;
/*
* Try every combination of local and foreign address pairs.
*/
for (ail = local; ail != NULL; ail = ail->ai_next) {
for (aif = foreign; aif != NULL; aif = aif->ai_next) {
if (ail->ai_family != aif->ai_family)
continue;
infamily = true;
if (!tcpdrop(ail->ai_addr, aif->ai_addr))
ok = false;
}
}
if (!infamily) {
warnx("%s %s %s %s: different address families", lhost, lport,
fhost, fport);
ok = false;
}
freeaddrinfo(local);
freeaddrinfo(foreign);
return (ok);
}
static bool
tcpdropconn(const struct in_conninfo *inc)
{
struct sockaddr *local, *foreign;
struct sockaddr_in6 sin6[2];
struct sockaddr_in sin4[2];
if ((inc->inc_flags & INC_ISIPV6) != 0) {
memset(sin6, 0, sizeof sin6);
sin6[TCPDROP_LOCAL].sin6_len = sizeof sin6[TCPDROP_LOCAL];
sin6[TCPDROP_LOCAL].sin6_family = AF_INET6;
sin6[TCPDROP_LOCAL].sin6_port = inc->inc_lport;
memcpy(&sin6[TCPDROP_LOCAL].sin6_addr, &inc->inc6_laddr,
sizeof inc->inc6_laddr);
local = (struct sockaddr *)&sin6[TCPDROP_LOCAL];
sin6[TCPDROP_FOREIGN].sin6_len = sizeof sin6[TCPDROP_FOREIGN];
sin6[TCPDROP_FOREIGN].sin6_family = AF_INET6;
sin6[TCPDROP_FOREIGN].sin6_port = inc->inc_fport;
memcpy(&sin6[TCPDROP_FOREIGN].sin6_addr, &inc->inc6_faddr,
sizeof inc->inc6_faddr);
foreign = (struct sockaddr *)&sin6[TCPDROP_FOREIGN];
} else {
memset(sin4, 0, sizeof sin4);
sin4[TCPDROP_LOCAL].sin_len = sizeof sin4[TCPDROP_LOCAL];
sin4[TCPDROP_LOCAL].sin_family = AF_INET;
sin4[TCPDROP_LOCAL].sin_port = inc->inc_lport;
memcpy(&sin4[TCPDROP_LOCAL].sin_addr, &inc->inc_laddr,
sizeof inc->inc_laddr);
local = (struct sockaddr *)&sin4[TCPDROP_LOCAL];
sin4[TCPDROP_FOREIGN].sin_len = sizeof sin4[TCPDROP_FOREIGN];
sin4[TCPDROP_FOREIGN].sin_family = AF_INET;
sin4[TCPDROP_FOREIGN].sin_port = inc->inc_fport;
memcpy(&sin4[TCPDROP_FOREIGN].sin_addr, &inc->inc_faddr,
sizeof inc->inc_faddr);
foreign = (struct sockaddr *)&sin4[TCPDROP_FOREIGN];
}
return (tcpdrop(local, foreign));
}
static void
usage(void)
{
fprintf(stderr,
"usage: tcpdrop local-address local-port foreign-address foreign-port\n"
" tcpdrop local-address:local-port foreign-address:foreign-port\n"
" tcpdrop local-address.local-port foreign-address.foreign-port\n"
" tcpdrop [-l] -a\n"
" tcpdrop [-l] -C cc-algo [-S stack] [-s state]\n"
" tcpdrop [-l] [-C cc-algo] -S stack [-s state]\n"
" tcpdrop [-l] [-C cc-algo] [-S stack] -s state\n");
exit(1);
}
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