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
|
/* Shared library add-on to iptables to add state tracking support. */
#include <stdio.h>
#include <netdb.h>
#include <string.h>
#include <stdlib.h>
#include <getopt.h>
#include <xtables.h>
#include <linux/netfilter/nf_conntrack_common.h>
#include <linux/netfilter/xt_state.h>
#ifndef XT_STATE_UNTRACKED
#define XT_STATE_UNTRACKED (1 << (IP_CT_NUMBER + 1))
#endif
static void
state_help(void)
{
printf(
"state match options:\n"
" [!] --state [INVALID|ESTABLISHED|NEW|RELATED|UNTRACKED][,...]\n"
" State(s) to match\n");
}
static const struct option state_opts[] = {
{ "state", 1, NULL, '1' },
{ .name = NULL }
};
static int
state_parse_state(const char *state, size_t len, struct xt_state_info *sinfo)
{
if (strncasecmp(state, "INVALID", len) == 0)
sinfo->statemask |= XT_STATE_INVALID;
else if (strncasecmp(state, "NEW", len) == 0)
sinfo->statemask |= XT_STATE_BIT(IP_CT_NEW);
else if (strncasecmp(state, "ESTABLISHED", len) == 0)
sinfo->statemask |= XT_STATE_BIT(IP_CT_ESTABLISHED);
else if (strncasecmp(state, "RELATED", len) == 0)
sinfo->statemask |= XT_STATE_BIT(IP_CT_RELATED);
else if (strncasecmp(state, "UNTRACKED", len) == 0)
sinfo->statemask |= XT_STATE_UNTRACKED;
else
return 0;
return 1;
}
static void
state_parse_states(const char *arg, struct xt_state_info *sinfo)
{
const char *comma;
while ((comma = strchr(arg, ',')) != NULL) {
if (comma == arg || !state_parse_state(arg, comma-arg, sinfo))
xtables_error(PARAMETER_PROBLEM, "Bad state \"%s\"", arg);
arg = comma+1;
}
if (!*arg)
xtables_error(PARAMETER_PROBLEM, "\"--state\" requires a list of "
"states with no spaces, e.g. "
"ESTABLISHED,RELATED");
if (strlen(arg) == 0 || !state_parse_state(arg, strlen(arg), sinfo))
xtables_error(PARAMETER_PROBLEM, "Bad state \"%s\"", arg);
}
static int
state_parse(int c, char **argv, int invert, unsigned int *flags,
const void *entry,
struct xt_entry_match **match)
{
struct xt_state_info *sinfo = (struct xt_state_info *)(*match)->data;
switch (c) {
case '1':
xtables_check_inverse(optarg, &invert, &optind, 0, argv);
state_parse_states(optarg, sinfo);
if (invert)
sinfo->statemask = ~sinfo->statemask;
*flags = 1;
break;
default:
return 0;
}
return 1;
}
static void state_final_check(unsigned int flags)
{
if (!flags)
xtables_error(PARAMETER_PROBLEM, "You must specify \"--state\"");
}
static void state_print_state(unsigned int statemask)
{
const char *sep = "";
if (statemask & XT_STATE_INVALID) {
printf("%sINVALID", sep);
sep = ",";
}
if (statemask & XT_STATE_BIT(IP_CT_NEW)) {
printf("%sNEW", sep);
sep = ",";
}
if (statemask & XT_STATE_BIT(IP_CT_RELATED)) {
printf("%sRELATED", sep);
sep = ",";
}
if (statemask & XT_STATE_BIT(IP_CT_ESTABLISHED)) {
printf("%sESTABLISHED", sep);
sep = ",";
}
if (statemask & XT_STATE_UNTRACKED) {
printf("%sUNTRACKED", sep);
sep = ",";
}
printf(" ");
}
static void
state_print(const void *ip,
const struct xt_entry_match *match,
int numeric)
{
const struct xt_state_info *sinfo = (const void *)match->data;
printf("state ");
state_print_state(sinfo->statemask);
}
static void state_save(const void *ip, const struct xt_entry_match *match)
{
const struct xt_state_info *sinfo = (const void *)match->data;
printf("--state ");
state_print_state(sinfo->statemask);
}
static struct xtables_match state_match = {
.family = NFPROTO_UNSPEC,
.name = "state",
.version = XTABLES_VERSION,
.size = XT_ALIGN(sizeof(struct xt_state_info)),
.userspacesize = XT_ALIGN(sizeof(struct xt_state_info)),
.help = state_help,
.parse = state_parse,
.final_check = state_final_check,
.print = state_print,
.save = state_save,
.extra_opts = state_opts,
};
void _init(void)
{
xtables_register_match(&state_match);
}
|
