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
|
/*
* (C) 2005 by Pablo Neira Ayuso <pablo@eurodev.net>
* Harald Welte <laforge@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 <netinet/in.h> /* For htons */
#include <netinet/ip_icmp.h>
#include <libnetfilter_conntrack/libnetfilter_conntrack.h>
#include "conntrack.h"
static struct option opts[] = {
{"icmp-type", 1, 0, '1'},
{"icmp-code", 1, 0, '2'},
{"icmp-id", 1, 0, '3'},
{0, 0, 0, 0}
};
enum icmp_param_flags {
ICMP_TYPE_BIT = 0,
ICMP_TYPE = (1 << ICMP_TYPE_BIT),
ICMP_CODE_BIT = 1,
ICMP_CODE = (1 << ICMP_CODE_BIT),
ICMP_ID_BIT = 2,
ICMP_ID = (1 << ICMP_ID_BIT)
};
void help()
{
fprintf(stdout, "--icmp-type icmp type\n");
fprintf(stdout, "--icmp-code icmp code\n");
fprintf(stdout, "--icmp-id icmp id\n");
}
/* Add 1; spaces filled with 0. */
static u_int8_t invmap[]
= { [ICMP_ECHO] = ICMP_ECHOREPLY + 1,
[ICMP_ECHOREPLY] = ICMP_ECHO + 1,
[ICMP_TIMESTAMP] = ICMP_TIMESTAMPREPLY + 1,
[ICMP_TIMESTAMPREPLY] = ICMP_TIMESTAMP + 1,
[ICMP_INFO_REQUEST] = ICMP_INFO_REPLY + 1,
[ICMP_INFO_REPLY] = ICMP_INFO_REQUEST + 1,
[ICMP_ADDRESS] = ICMP_ADDRESSREPLY + 1,
[ICMP_ADDRESSREPLY] = ICMP_ADDRESS + 1};
int parse(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->l4dst.icmp.type = atoi(optarg);
reply->l4dst.icmp.type =
invmap[orig->l4dst.icmp.type] - 1;
*flags |= ICMP_TYPE;
}
break;
case '2':
if (optarg) {
orig->l4dst.icmp.code = atoi(optarg);
reply->l4dst.icmp.code = 0;
*flags |= ICMP_CODE;
}
break;
case '3':
if (optarg) {
orig->l4src.icmp.id = atoi(optarg);
reply->l4dst.icmp.id = 0;
*flags |= ICMP_ID;
}
break;
}
return 1;
}
int final_check(unsigned int flags,
unsigned int command,
struct nfct_tuple *orig,
struct nfct_tuple *reply)
{
if (!(flags & ICMP_TYPE))
return 0;
else if (!(flags & ICMP_CODE))
return 0;
return 1;
}
static struct ctproto_handler icmp = {
.name = "icmp",
.protonum = IPPROTO_ICMP,
.parse_opts = parse,
.final_check = final_check,
.help = help,
.opts = opts,
.version = CONNTRACK_VERSION,
};
void __attribute__ ((constructor)) init(void);
void init(void)
{
register_proto(&icmp);
}
|
