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
226
227
228
229
230
231
232
233
234
235
236
237
238
239
|
/*
* (C) 2005-2007 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.
*
*/
#include <stdio.h>
#include <getopt.h>
#include <stdlib.h>
#include <string.h>
#include <netinet/in.h> /* For htons */
#include <libnetfilter_conntrack/libnetfilter_conntrack.h>
#include <libnetfilter_conntrack/libnetfilter_conntrack_tcp.h>
#include "conntrack.h"
enum {
CT_TCP_ORIG_SPORT = (1 << 0),
CT_TCP_ORIG_DPORT = (1 << 1),
CT_TCP_REPL_SPORT = (1 << 2),
CT_TCP_REPL_DPORT = (1 << 3),
CT_TCP_MASK_SPORT = (1 << 4),
CT_TCP_MASK_DPORT = (1 << 5),
CT_TCP_STATE = (1 << 6),
CT_TCP_EXPTUPLE_SPORT = (1 << 7),
CT_TCP_EXPTUPLE_DPORT = (1 << 8)
};
static struct option opts[] = {
{"orig-port-src", 1, 0, '1'},
{"sport", 1, 0, '1'},
{"orig-port-dst", 1, 0, '2'},
{"dport", 1, 0, '2'},
{"reply-port-src", 1, 0, '3'},
{"reply-port-dst", 1, 0, '4'},
{"mask-port-src", 1, 0, '5'},
{"mask-port-dst", 1, 0, '6'},
{"state", 1, 0, '7'},
{"tuple-port-src", 1, 0, '8'},
{"tuple-port-dst", 1, 0, '9'},
{0, 0, 0, 0}
};
#define TCP_NUMBER_OF_OPT 10
static const char *tcp_optflags[TCP_NUMBER_OF_OPT] = {
"sport", "dport", "reply-port-src", "reply-port-dst", "mask-port-src",
"mask-port-dst", "state", "tuple-port-src", "tuple-port-dst"
};
static char tcp_commands_v_options[NUMBER_OF_CMD][TCP_NUMBER_OF_OPT] =
/* Well, it's better than "Re: Sevilla vs Betis" */
{
/* 1 2 3 4 5 6 7 8 9 */
/*CT_LIST*/ {2,2,2,2,0,0,2,0,0},
/*CT_CREATE*/ {3,3,3,3,0,0,1,0,0},
/*CT_UPDATE*/ {2,2,2,2,0,0,2,0,0},
/*CT_DELETE*/ {2,2,2,2,0,0,2,0,0},
/*CT_GET*/ {3,3,3,3,0,0,2,0,0},
/*CT_FLUSH*/ {0,0,0,0,0,0,0,0,0},
/*CT_EVENT*/ {2,2,2,2,0,0,2,0,0},
/*CT_VERSION*/ {0,0,0,0,0,0,0,0,0},
/*CT_HELP*/ {0,0,0,0,0,0,0,0,0},
/*EXP_LIST*/ {0,0,0,0,0,0,0,0,0},
/*EXP_CREATE*/ {1,1,0,0,1,1,0,1,1},
/*EXP_DELETE*/ {1,1,1,1,0,0,0,0,0},
/*EXP_GET*/ {1,1,1,1,0,0,0,0,0},
/*EXP_FLUSH*/ {0,0,0,0,0,0,0,0,0},
/*EXP_EVENT*/ {0,0,0,0,0,0,0,0,0},
};
static const char *tcp_states[TCP_CONNTRACK_MAX] = {
[TCP_CONNTRACK_NONE] = "NONE",
[TCP_CONNTRACK_SYN_SENT] = "SYN_SENT",
[TCP_CONNTRACK_SYN_RECV] = "SYN_RECV",
[TCP_CONNTRACK_ESTABLISHED] = "ESTABLISHED",
[TCP_CONNTRACK_FIN_WAIT] = "FIN_WAIT",
[TCP_CONNTRACK_CLOSE_WAIT] = "CLOSE_WAIT",
[TCP_CONNTRACK_LAST_ACK] = "LAST_ACK",
[TCP_CONNTRACK_TIME_WAIT] = "TIME_WAIT",
[TCP_CONNTRACK_CLOSE] = "CLOSE",
/* Since Linux kernel 2.6.31, LISTEN is SYN_SENT2. */
[TCP_CONNTRACK_SYN_SENT2] = "SYN_SENT2"
};
static void help(void)
{
fprintf(stdout, " --orig-port-src\t\toriginal source port\n");
fprintf(stdout, " --orig-port-dst\t\toriginal destination port\n");
fprintf(stdout, " --reply-port-src\t\treply source port\n");
fprintf(stdout, " --reply-port-dst\t\treply destination port\n");
fprintf(stdout, " --mask-port-src\t\tmask source port\n");
fprintf(stdout, " --mask-port-dst\t\tmask destination port\n");
fprintf(stdout, " --tuple-port-src\t\texpectation tuple src port\n");
fprintf(stdout, " --tuple-port-src\t\texpectation tuple dst port\n");
fprintf(stdout, " --state\t\t\tTCP state, fe. ESTABLISHED\n");
}
static int parse_options(char c,
struct nf_conntrack *ct,
struct nf_conntrack *exptuple,
struct nf_conntrack *mask,
unsigned int *flags)
{
int i;
uint16_t port;
switch(c) {
case '1':
port = htons(atoi(optarg));
nfct_set_attr_u16(ct, ATTR_ORIG_PORT_SRC, port);
nfct_set_attr_u8(ct, ATTR_ORIG_L4PROTO, IPPROTO_TCP);
*flags |= CT_TCP_ORIG_SPORT;
break;
case '2':
port = htons(atoi(optarg));
nfct_set_attr_u16(ct, ATTR_ORIG_PORT_DST, port);
nfct_set_attr_u8(ct, ATTR_ORIG_L4PROTO, IPPROTO_TCP);
*flags |= CT_TCP_ORIG_DPORT;
break;
case '3':
port = htons(atoi(optarg));
nfct_set_attr_u16(ct, ATTR_REPL_PORT_SRC, port);
nfct_set_attr_u8(ct, ATTR_REPL_L4PROTO, IPPROTO_TCP);
*flags |= CT_TCP_REPL_SPORT;
break;
case '4':
port = htons(atoi(optarg));
nfct_set_attr_u16(ct, ATTR_REPL_PORT_DST, port);
nfct_set_attr_u8(ct, ATTR_REPL_L4PROTO, IPPROTO_TCP);
*flags |= CT_TCP_REPL_DPORT;
break;
case '5':
port = htons(atoi(optarg));
nfct_set_attr_u16(mask, ATTR_ORIG_PORT_SRC, port);
nfct_set_attr_u8(mask, ATTR_ORIG_L4PROTO, IPPROTO_TCP);
*flags |= CT_TCP_MASK_SPORT;
break;
case '6':
port = htons(atoi(optarg));
nfct_set_attr_u16(mask, ATTR_ORIG_PORT_DST, port);
nfct_set_attr_u8(mask, ATTR_ORIG_L4PROTO, IPPROTO_TCP);
*flags |= CT_TCP_MASK_DPORT;
break;
case '7':
for (i=0; i<TCP_CONNTRACK_MAX; i++) {
if (strcmp(optarg, tcp_states[i]) == 0) {
nfct_set_attr_u8(ct, ATTR_TCP_STATE, i);
break;
}
}
/* For backward compatibility with Linux kernel < 2.6.31. */
if (strcmp(optarg, "LISTEN") == 0) {
nfct_set_attr_u8(ct, ATTR_TCP_STATE,
TCP_CONNTRACK_LISTEN);
} else if (i == TCP_CONNTRACK_MAX)
exit_error(PARAMETER_PROBLEM,
"unknown TCP state `%s'", optarg);
*flags |= CT_TCP_STATE;
break;
case '8':
port = htons(atoi(optarg));
nfct_set_attr_u16(exptuple, ATTR_ORIG_PORT_SRC, port);
nfct_set_attr_u8(exptuple, ATTR_ORIG_L4PROTO, port);
*flags |= CT_TCP_EXPTUPLE_SPORT;
break;
case '9':
port = htons(atoi(optarg));
nfct_set_attr_u16(exptuple, ATTR_ORIG_PORT_DST, port);
nfct_set_attr_u8(exptuple, ATTR_ORIG_L4PROTO, port);
*flags |= CT_TCP_EXPTUPLE_DPORT;
break;
}
return 1;
}
#define TCP_VALID_FLAGS_MAX 2
static unsigned int tcp_valid_flags[TCP_VALID_FLAGS_MAX] = {
CT_TCP_ORIG_SPORT | CT_TCP_ORIG_DPORT,
CT_TCP_REPL_SPORT | CT_TCP_REPL_DPORT,
};
static void final_check(unsigned int flags,
unsigned int cmd,
struct nf_conntrack *ct)
{
int ret, partial;
ret = generic_opt_check(flags, TCP_NUMBER_OF_OPT,
tcp_commands_v_options[cmd], tcp_optflags,
tcp_valid_flags, TCP_VALID_FLAGS_MAX, &partial);
if (!ret) {
switch(partial) {
case -1:
case 0:
exit_error(PARAMETER_PROBLEM, "you have to specify "
"`--sport' and "
"`--dport'");
break;
case 1:
exit_error(PARAMETER_PROBLEM, "you have to specify "
"`--reply-src-port' and "
"`--reply-dst-port'");
break;
}
}
/* Disable TCP window tracking for manually created TCP entries,
* otherwise this will not work. */
uint8_t tcp_flags = IP_CT_TCP_FLAG_BE_LIBERAL |
IP_CT_TCP_FLAG_SACK_PERM;
/* This allows to reopen a new connection directly from TIME-WAIT
* as RFC 1122 states. See nf_conntrack_proto_tcp.c for more info. */
if (nfct_get_attr_u8(ct, ATTR_TCP_STATE) >= TCP_CONNTRACK_TIME_WAIT)
tcp_flags |= IP_CT_TCP_FLAG_CLOSE_INIT;
nfct_set_attr_u8(ct, ATTR_TCP_FLAGS_ORIG, tcp_flags);
nfct_set_attr_u8(ct, ATTR_TCP_MASK_ORIG, tcp_flags);
nfct_set_attr_u8(ct, ATTR_TCP_FLAGS_REPL, tcp_flags);
nfct_set_attr_u8(ct, ATTR_TCP_MASK_REPL, tcp_flags);
}
static struct ctproto_handler tcp = {
.name = "tcp",
.protonum = IPPROTO_TCP,
.parse_opts = parse_options,
.final_check = final_check,
.help = help,
.opts = opts,
.version = VERSION,
};
void register_tcp(void)
{
register_proto(&tcp);
}
|
