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
|
/*
* (C) 2005 by Pablo Neira Ayuso <pablo@eurodev.net>
*
* 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 <netinet/in.h> /* For htons */
#include "conntrack.h"
#include <libnetfilter_conntrack/libnetfilter_conntrack.h>
static struct option opts[] = {
{"orig-port-src", 1, 0, '1'},
{"orig-port-dst", 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'},
{0, 0, 0, 0}
};
enum udp_param_flags {
ORIG_SPORT_BIT = 0,
ORIG_SPORT = (1 << ORIG_SPORT_BIT),
ORIG_DPORT_BIT = 1,
ORIG_DPORT = (1 << ORIG_DPORT_BIT),
REPL_SPORT_BIT = 2,
REPL_SPORT = (1 << REPL_SPORT_BIT),
REPL_DPORT_BIT = 3,
REPL_DPORT = (1 << REPL_DPORT_BIT),
MASK_SPORT_BIT = 4,
MASK_SPORT = (1 << MASK_SPORT_BIT),
MASK_DPORT_BIT = 5,
MASK_DPORT = (1 << MASK_DPORT_BIT),
};
void help()
{
fprintf(stdout, "--orig-port-src original source port\n");
fprintf(stdout, "--orig-port-dst original destination port\n");
fprintf(stdout, "--reply-port-src reply source port\n");
fprintf(stdout, "--reply-port-dst reply destination port\n");
fprintf(stdout, "--mask-port-src mask source port\n");
fprintf(stdout, "--mask-port-dst mask destination port\n");
}
int parse_options(char c, char *argv[],
struct nfct_tuple *orig,
struct nfct_tuple *reply,
struct nfct_tuple *mask,
union nfct_protoinfo *proto,
unsigned int *flags)
{
switch(c) {
case '1':
if (optarg) {
orig->l4src.udp.port = htons(atoi(optarg));
*flags |= ORIG_SPORT;
}
break;
case '2':
if (optarg) {
orig->l4dst.udp.port = htons(atoi(optarg));
*flags |= ORIG_DPORT;
}
break;
case '3':
if (optarg) {
reply->l4src.udp.port = htons(atoi(optarg));
*flags |= REPL_SPORT;
}
break;
case '4':
if (optarg) {
reply->l4dst.udp.port = htons(atoi(optarg));
*flags |= REPL_DPORT;
}
break;
case '5':
if (optarg) {
mask->l4src.udp.port = htons(atoi(optarg));
*flags |= MASK_SPORT;
}
break;
case '6':
if (optarg) {
mask->l4dst.udp.port = htons(atoi(optarg));
*flags |= MASK_DPORT;
}
break;
}
return 1;
}
int final_check(unsigned int flags,
struct nfct_tuple *orig,
struct nfct_tuple *reply)
{
if ((flags & (ORIG_SPORT|ORIG_DPORT))
&& !(flags & (REPL_SPORT|REPL_DPORT))) {
reply->l4src.udp.port = orig->l4dst.udp.port;
reply->l4dst.udp.port = orig->l4src.udp.port;
return 1;
} else if (!(flags & (ORIG_SPORT|ORIG_DPORT))
&& (flags & (REPL_SPORT|REPL_DPORT))) {
orig->l4src.udp.port = reply->l4dst.udp.port;
orig->l4dst.udp.port = reply->l4src.udp.port;
return 1;
}
if ((flags & (ORIG_SPORT|ORIG_DPORT))
&& ((flags & (REPL_SPORT|REPL_DPORT))))
return 1;
return 0;
}
static struct ctproto_handler udp = {
.name = "udp",
.protonum = IPPROTO_UDP,
.parse_opts = parse_options,
.final_check = final_check,
.help = help,
.opts = opts,
.version = VERSION,
};
void __attribute__ ((constructor)) init(void);
void init(void)
{
register_proto(&udp);
}
|
