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
|
/* Shared library add-on to iptables to add TTL matching support
* (C) 2000 by Harald Welte <laforge@gnumonks.org>
*
* This program is released under the terms of GNU GPL */
#include <stdio.h>
#include <xtables.h>
#include <linux/netfilter_ipv4/ipt_ttl.h>
enum {
O_TTL_EQ = 0,
O_TTL_LT,
O_TTL_GT,
F_TTL_EQ = 1 << O_TTL_EQ,
F_TTL_LT = 1 << O_TTL_LT,
F_TTL_GT = 1 << O_TTL_GT,
F_ANY = F_TTL_EQ | F_TTL_LT | F_TTL_GT,
};
static void ttl_help(void)
{
printf(
"ttl match options:\n"
"[!] --ttl-eq value Match time to live value\n"
" --ttl-lt value Match TTL < value\n"
" --ttl-gt value Match TTL > value\n");
}
static void ttl_parse(struct xt_option_call *cb)
{
struct ipt_ttl_info *info = cb->data;
xtables_option_parse(cb);
switch (cb->entry->id) {
case O_TTL_EQ:
info->mode = cb->invert ? IPT_TTL_NE : IPT_TTL_EQ;
break;
case O_TTL_LT:
info->mode = IPT_TTL_LT;
break;
case O_TTL_GT:
info->mode = IPT_TTL_GT;
break;
}
}
static void ttl_check(struct xt_fcheck_call *cb)
{
if (!(cb->xflags & F_ANY))
xtables_error(PARAMETER_PROBLEM,
"TTL match: You must specify one of "
"`--ttl-eq', `--ttl-lt', `--ttl-gt");
}
static void ttl_print(const void *ip, const struct xt_entry_match *match,
int numeric)
{
const struct ipt_ttl_info *info =
(struct ipt_ttl_info *) match->data;
printf(" TTL match ");
switch (info->mode) {
case IPT_TTL_EQ:
printf("TTL ==");
break;
case IPT_TTL_NE:
printf("TTL !=");
break;
case IPT_TTL_LT:
printf("TTL <");
break;
case IPT_TTL_GT:
printf("TTL >");
break;
}
printf(" %u", info->ttl);
}
static void ttl_save(const void *ip, const struct xt_entry_match *match)
{
const struct ipt_ttl_info *info =
(struct ipt_ttl_info *) match->data;
switch (info->mode) {
case IPT_TTL_EQ:
printf(" --ttl-eq");
break;
case IPT_TTL_NE:
printf(" ! --ttl-eq");
break;
case IPT_TTL_LT:
printf(" --ttl-lt");
break;
case IPT_TTL_GT:
printf(" --ttl-gt");
break;
default:
/* error */
break;
}
printf(" %u", info->ttl);
}
static int ttl_xlate(struct xt_xlate *xl,
const struct xt_xlate_mt_params *params)
{
const struct ipt_ttl_info *info =
(struct ipt_ttl_info *) params->match->data;
switch (info->mode) {
case IPT_TTL_EQ:
xt_xlate_add(xl, "ip ttl");
break;
case IPT_TTL_NE:
xt_xlate_add(xl, "ip ttl !=");
break;
case IPT_TTL_LT:
xt_xlate_add(xl, "ip ttl lt");
break;
case IPT_TTL_GT:
xt_xlate_add(xl, "ip ttl gt");
break;
default:
/* Should not happen. */
return 0;
}
xt_xlate_add(xl, " %u", info->ttl);
return 1;
}
#define s struct ipt_ttl_info
static const struct xt_option_entry ttl_opts[] = {
{.name = "ttl-lt", .id = O_TTL_LT, .excl = F_ANY, .type = XTTYPE_UINT8,
.flags = XTOPT_PUT, XTOPT_POINTER(s, ttl)},
{.name = "ttl-gt", .id = O_TTL_GT, .excl = F_ANY, .type = XTTYPE_UINT8,
.flags = XTOPT_PUT, XTOPT_POINTER(s, ttl)},
{.name = "ttl-eq", .id = O_TTL_EQ, .excl = F_ANY, .type = XTTYPE_UINT8,
.flags = XTOPT_INVERT | XTOPT_PUT, XTOPT_POINTER(s, ttl)},
{.name = "ttl", .id = O_TTL_EQ, .excl = F_ANY, .type = XTTYPE_UINT8,
.flags = XTOPT_PUT, XTOPT_POINTER(s, ttl)},
XTOPT_TABLEEND,
};
#undef s
static struct xtables_match ttl_mt_reg = {
.name = "ttl",
.version = XTABLES_VERSION,
.family = NFPROTO_IPV4,
.size = XT_ALIGN(sizeof(struct ipt_ttl_info)),
.userspacesize = XT_ALIGN(sizeof(struct ipt_ttl_info)),
.help = ttl_help,
.print = ttl_print,
.save = ttl_save,
.x6_parse = ttl_parse,
.x6_fcheck = ttl_check,
.x6_options = ttl_opts,
.xlate = ttl_xlate,
};
void _init(void)
{
xtables_register_match(&ttl_mt_reg);
}
|
