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
|
#define _GNU_SOURCE
#include <errno.h>
#include <stdbool.h>
#include <string.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <xtables.h>
#include <linux/netfilter/xt_connlabel.h>
#include <libnetfilter_conntrack/libnetfilter_conntrack.h>
enum {
O_LABEL = 0,
O_SET = 1,
};
static struct nfct_labelmap *map;
static void connlabel_mt_help(void)
{
puts(
"connlabel match options:\n"
"[!] --label name Match if label has been set on connection\n"
" --set Set label on connection");
}
static const struct xt_option_entry connlabel_mt_opts[] = {
{.name = "label", .id = O_LABEL, .type = XTTYPE_STRING,
.min = 1, .flags = XTOPT_MAND|XTOPT_INVERT},
{.name = "set", .id = O_SET, .type = XTTYPE_NONE},
XTOPT_TABLEEND,
};
/* cannot do this via _init, else static builds might spew error message
* for every iptables invocation.
*/
static int connlabel_open(void)
{
const char *fname;
if (map)
return 0;
map = nfct_labelmap_new(NULL);
if (map != NULL)
return 0;
fname = nfct_labels_get_path();
if (errno) {
fprintf(stderr, "Warning: cannot open %s: %s\n",
fname, strerror(errno));
} else {
xtables_error(RESOURCE_PROBLEM,
"cannot parse %s: no labels found", fname);
}
return 1;
}
static int connlabel_value_parse(const char *in)
{
char *end;
unsigned long value = strtoul(in, &end, 0);
if (in[0] == '\0' || *end != '\0')
return -1;
return value;
}
static void connlabel_mt_parse(struct xt_option_call *cb)
{
struct xt_connlabel_mtinfo *info = cb->data;
int tmp;
xtables_option_parse(cb);
switch (cb->entry->id) {
case O_LABEL:
tmp = connlabel_value_parse(cb->arg);
if (tmp < 0 && !connlabel_open())
tmp = nfct_labelmap_get_bit(map, cb->arg);
if (tmp < 0)
xtables_error(PARAMETER_PROBLEM,
"label '%s' not found or invalid value",
cb->arg);
info->bit = tmp;
if (cb->invert)
info->options |= XT_CONNLABEL_OP_INVERT;
break;
case O_SET:
info->options |= XT_CONNLABEL_OP_SET;
break;
}
}
static const char *connlabel_get_name(int b)
{
const char *name;
if (connlabel_open())
return NULL;
name = nfct_labelmap_get_name(map, b);
if (name && strcmp(name, ""))
return name;
return NULL;
}
static void
connlabel_mt_print_op(const struct xt_connlabel_mtinfo *info, const char *prefix)
{
if (info->options & XT_CONNLABEL_OP_SET)
printf(" %sset", prefix);
}
static void
connlabel_mt_print(const void *ip, const struct xt_entry_match *match, int numeric)
{
const struct xt_connlabel_mtinfo *info = (const void *)match->data;
const char *name = connlabel_get_name(info->bit);
printf(" connlabel");
if (info->options & XT_CONNLABEL_OP_INVERT)
printf(" !");
if (numeric || name == NULL) {
printf(" %u", info->bit);
} else {
printf(" '%s'", name);
}
connlabel_mt_print_op(info, "");
}
static void
connlabel_mt_save(const void *ip, const struct xt_entry_match *match)
{
const struct xt_connlabel_mtinfo *info = (const void *)match->data;
const char *name = connlabel_get_name(info->bit);
if (info->options & XT_CONNLABEL_OP_INVERT)
printf(" !");
if (name)
printf(" --label \"%s\"", name);
else
printf(" --label \"%u\"", info->bit);
connlabel_mt_print_op(info, "--");
}
static int connlabel_mt_xlate(struct xt_xlate *xl,
const struct xt_xlate_mt_params *params)
{
const struct xt_connlabel_mtinfo *info =
(const void *)params->match->data;
const char *name = connlabel_get_name(info->bit);
char *valbuf = NULL;
if (name == NULL) {
if (asprintf(&valbuf, "%u", info->bit) < 0)
return 0;
name = valbuf;
}
if (info->options & XT_CONNLABEL_OP_SET)
xt_xlate_add(xl, "ct label set %s ", name);
xt_xlate_add(xl, "ct label ");
if (info->options & XT_CONNLABEL_OP_INVERT)
xt_xlate_add(xl, "and %s != ", name);
xt_xlate_add(xl, "%s", name);
free(valbuf);
return 1;
}
static struct xtables_match connlabel_mt_reg = {
.family = NFPROTO_UNSPEC,
.name = "connlabel",
.version = XTABLES_VERSION,
.size = XT_ALIGN(sizeof(struct xt_connlabel_mtinfo)),
.userspacesize = offsetof(struct xt_connlabel_mtinfo, bit),
.help = connlabel_mt_help,
.print = connlabel_mt_print,
.save = connlabel_mt_save,
.x6_parse = connlabel_mt_parse,
.x6_options = connlabel_mt_opts,
.xlate = connlabel_mt_xlate,
};
void _init(void)
{
xtables_register_match(&connlabel_mt_reg);
}
|
