1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
|
/*
* (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 "debug.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(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(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(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(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)
{
uint8_t flags;
/* XXX: related connections */
if (nfct_attr_is_set(ct, ATTR_STATUS)) {
uint32_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);
}
|
