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/*
* (C) 2006 by Pablo Neira Ayuso <pablo@netfilter.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "netlink.h"
#include "conntrackd.h"
#include "traffic_stats.h"
#include "ignore.h"
#include "log.h"
#include <libnfnetlink/libnfnetlink.h>
#include <libnetfilter_conntrack/libnetfilter_conntrack.h>
#include <errno.h>
#include "us-conntrack.h"
#include <signal.h>
#include <stdlib.h>
#include "network.h"
int ignore_conntrack(struct nf_conntrack *ct)
{
/* ignore a certain protocol */
if (CONFIG(ignore_protocol)[nfct_get_attr_u8(ct, ATTR_ORIG_L4PROTO)])
return 1;
/* Accept DNAT'ed traffic: not really coming to the local machine */
if (nfct_getobjopt(ct, NFCT_GOPT_IS_DNAT)) {
debug_ct(ct, "DNAT");
return 0;
}
/* Accept SNAT'ed traffic: not really coming to the local machine */
if (nfct_getobjopt(ct, NFCT_GOPT_IS_SNAT)) {
debug_ct(ct, "SNAT");
return 0;
}
/* Ignore traffic */
if (ignore_pool_test(STATE(ignore_pool), ct)) {
debug_ct(ct, "ignore traffic");
return 1;
}
return 0;
}
static int event_handler(enum nf_conntrack_msg_type type,
struct nf_conntrack *ct,
void *data)
{
/*
* Ignore this conntrack: it talks about a
* connection that is not interesting for us.
*/
if (ignore_conntrack(ct))
return NFCT_CB_STOP;
switch(type) {
case NFCT_T_NEW:
STATE(mode)->event_new(ct);
break;
case NFCT_T_UPDATE:
STATE(mode)->event_upd(ct);
break;
case NFCT_T_DESTROY:
if (STATE(mode)->event_dst(ct))
update_traffic_stats(ct);
break;
default:
dlog(STATE(log), LOG_WARNING, "unknown msg from ctnetlink\n");
break;
}
return NFCT_CB_CONTINUE;
}
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/fcntl.h>
int nl_init_event_handler(void)
{
STATE(event) = nfct_open(CONNTRACK, NFCT_ALL_CT_GROUPS);
if (!STATE(event))
return -1;
fcntl(nfct_fd(STATE(event)), F_SETFL, O_NONBLOCK);
/* set up socket buffer size */
if (CONFIG(netlink_buffer_size))
nfnl_rcvbufsiz(nfct_nfnlh(STATE(event)),
CONFIG(netlink_buffer_size));
else {
socklen_t socklen = sizeof(unsigned int);
unsigned int read_size;
/* get current buffer size */
getsockopt(nfct_fd(STATE(event)), SOL_SOCKET,
SO_RCVBUF, &read_size, &socklen);
CONFIG(netlink_buffer_size) = read_size;
}
/* ensure that maximum grown size is >= than maximum size */
if (CONFIG(netlink_buffer_size_max_grown) < CONFIG(netlink_buffer_size))
CONFIG(netlink_buffer_size_max_grown) =
CONFIG(netlink_buffer_size);
/* register callback for events */
nfct_callback_register(STATE(event), NFCT_T_ALL, event_handler, NULL);
return 0;
}
static int dump_handler(enum nf_conntrack_msg_type type,
struct nf_conntrack *ct,
void *data)
{
/*
* Ignore this conntrack: it talks about a
* connection that is not interesting for us.
*/
if (ignore_conntrack(ct))
return NFCT_CB_CONTINUE;
switch(type) {
case NFCT_T_UPDATE:
STATE(mode)->dump(ct);
break;
default:
dlog(STATE(log), LOG_WARNING, "unknown msg from ctnetlink");
break;
}
return NFCT_CB_CONTINUE;
}
int nl_init_dump_handler(void)
{
/* open dump netlink socket */
STATE(dump) = nfct_open(CONNTRACK, 0);
if (!STATE(dump))
return -1;
/* register callback for dumped entries */
nfct_callback_register(STATE(dump), NFCT_T_ALL, dump_handler, NULL);
if (nl_dump_conntrack_table() == -1)
return -1;
return 0;
}
static int warned = 0;
void nl_resize_socket_buffer(struct nfct_handle *h)
{
unsigned int s = CONFIG(netlink_buffer_size) * 2;
/* already warned that we have reached the maximum buffer size */
if (warned)
return;
if (s > CONFIG(netlink_buffer_size_max_grown)) {
dlog(STATE(log), LOG_WARNING,
"maximum netlink socket buffer "
"size has been reached. We are likely to "
"be losing events, this may lead to "
"unsynchronized replicas. Please, consider "
"increasing netlink socket buffer size via "
"SocketBufferSize and "
"SocketBufferSizeMaxGrown clauses in "
"conntrackd.conf");
s = CONFIG(netlink_buffer_size_max_grown);
warned = 1;
}
CONFIG(netlink_buffer_size) = nfnl_rcvbufsiz(nfct_nfnlh(h), s);
/* notify the sysadmin */
dlog(STATE(log), LOG_NOTICE, "netlink socket buffer size "
"has been set to %u bytes",
CONFIG(netlink_buffer_size));
}
int nl_dump_conntrack_table(void)
{
return nfct_query(STATE(dump), NFCT_Q_DUMP, &CONFIG(family));
}
/* This function modifies the conntrack passed as argument! */
int nl_create_conntrack(struct nf_conntrack *ct)
{
u_int8_t flags;
/* XXX: related connections */
if (nfct_attr_is_set(ct, ATTR_STATUS)) {
u_int32_t status = nfct_get_attr_u32(ct, ATTR_STATUS);
status &= ~IPS_EXPECTED;
nfct_set_attr_u32(ct, ATTR_STATUS, status);
}
nfct_setobjopt(ct, NFCT_SOPT_SETUP_REPLY);
/*
* TCP flags to overpass window tracking for recovered connections
*/
flags = IP_CT_TCP_FLAG_BE_LIBERAL | IP_CT_TCP_FLAG_SACK_PERM;
nfct_set_attr_u8(ct, ATTR_TCP_FLAGS_ORIG, flags);
nfct_set_attr_u8(ct, ATTR_TCP_MASK_ORIG, flags);
nfct_set_attr_u8(ct, ATTR_TCP_FLAGS_REPL, flags);
nfct_set_attr_u8(ct, ATTR_TCP_MASK_REPL, flags);
return nfct_query(STATE(dump), NFCT_Q_CREATE_UPDATE, ct);
}
int nl_destroy_conntrack(struct nf_conntrack *ct)
{
return nfct_query(STATE(dump), NFCT_Q_DESTROY, ct);
}
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