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
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
|
/* Shared library add-on to ip6tables to add Dst header support. */
#include <stdio.h>
#include <netdb.h>
#include <string.h>
#include <stdlib.h>
#include <getopt.h>
#include <errno.h>
#include <xtables.h>
#include <linux/netfilter_ipv6/ip6t_opts.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
static void dst_help(void)
{
printf(
"dst match options:\n"
"[!] --dst-len length total length of this header\n"
" --dst-opts TYPE[:LEN][,TYPE[:LEN]...]\n"
" Options and its length (list, max: %d)\n",
IP6T_OPTS_OPTSNR);
}
static const struct option dst_opts[] = {
{ .name = "dst-len", .has_arg = 1, .val = '1' },
{ .name = "dst-opts", .has_arg = 1, .val = '2' },
{ .name = "dst-not-strict", .has_arg = 1, .val = '3' },
{ .name = NULL }
};
static u_int32_t
parse_opts_num(const char *idstr, const char *typestr)
{
unsigned long int id;
char* ep;
id = strtoul(idstr, &ep, 0);
if ( idstr == ep ) {
xtables_error(PARAMETER_PROBLEM,
"dst: no valid digits in %s `%s'", typestr, idstr);
}
if ( id == ULONG_MAX && errno == ERANGE ) {
xtables_error(PARAMETER_PROBLEM,
"%s `%s' specified too big: would overflow",
typestr, idstr);
}
if ( *idstr != '\0' && *ep != '\0' ) {
xtables_error(PARAMETER_PROBLEM,
"dst: error parsing %s `%s'", typestr, idstr);
}
return id;
}
static int
parse_options(const char *optsstr, u_int16_t *opts)
{
char *buffer, *cp, *next, *range;
unsigned int i;
buffer = strdup(optsstr);
if (!buffer)
xtables_error(OTHER_PROBLEM, "strdup failed");
for (cp = buffer, i = 0; cp && i < IP6T_OPTS_OPTSNR; cp = next, i++)
{
next = strchr(cp, ',');
if (next)
*next++='\0';
range = strchr(cp, ':');
if (range) {
if (i == IP6T_OPTS_OPTSNR-1)
xtables_error(PARAMETER_PROBLEM,
"too many ports specified");
*range++ = '\0';
}
opts[i] = (parse_opts_num(cp, "opt") & 0xFF) << 8;
if (range) {
if (opts[i] == 0)
xtables_error(PARAMETER_PROBLEM,
"PAD0 hasn't got length");
opts[i] |= parse_opts_num(range, "length") & 0xFF;
} else
opts[i] |= (0x00FF);
#ifdef DEBUG
printf("opts str: %s %s\n", cp, range);
printf("opts opt: %04X\n", opts[i]);
#endif
}
if (cp)
xtables_error(PARAMETER_PROBLEM, "too many addresses specified");
free(buffer);
#ifdef DEBUG
printf("addr nr: %d\n", i);
#endif
return i;
}
static void dst_init(struct xt_entry_match *m)
{
struct ip6t_opts *optinfo = (struct ip6t_opts *)m->data;
optinfo->hdrlen = 0;
optinfo->flags = 0;
optinfo->invflags = 0;
optinfo->optsnr = 0;
}
static int dst_parse(int c, char **argv, int invert, unsigned int *flags,
const void *entry, struct xt_entry_match **match)
{
struct ip6t_opts *optinfo = (struct ip6t_opts *)(*match)->data;
switch (c) {
case '1':
if (*flags & IP6T_OPTS_LEN)
xtables_error(PARAMETER_PROBLEM,
"Only one `--dst-len' allowed");
xtables_check_inverse(optarg, &invert, &optind, 0, argv);
optinfo->hdrlen = parse_opts_num(optarg, "length");
if (invert)
optinfo->invflags |= IP6T_OPTS_INV_LEN;
optinfo->flags |= IP6T_OPTS_LEN;
*flags |= IP6T_OPTS_LEN;
break;
case '2':
if (*flags & IP6T_OPTS_OPTS)
xtables_error(PARAMETER_PROBLEM,
"Only one `--dst-opts' allowed");
xtables_check_inverse(optarg, &invert, &optind, 0, argv);
if (invert)
xtables_error(PARAMETER_PROBLEM,
" '!' not allowed with `--dst-opts'");
optinfo->optsnr = parse_options(optarg, optinfo->opts);
optinfo->flags |= IP6T_OPTS_OPTS;
*flags |= IP6T_OPTS_OPTS;
break;
case '3':
if (*flags & IP6T_OPTS_NSTRICT)
xtables_error(PARAMETER_PROBLEM,
"Only one `--dst-not-strict' allowed");
if ( !(*flags & IP6T_OPTS_OPTS) )
xtables_error(PARAMETER_PROBLEM,
"`--dst-opts ...' required before "
"`--dst-not-strict'");
optinfo->flags |= IP6T_OPTS_NSTRICT;
*flags |= IP6T_OPTS_NSTRICT;
break;
default:
return 0;
}
return 1;
}
static void
print_options(unsigned int optsnr, u_int16_t *optsp)
{
unsigned int i;
for(i = 0; i < optsnr; i++) {
printf("%d", (optsp[i] & 0xFF00) >> 8);
if ((optsp[i] & 0x00FF) != 0x00FF)
printf(":%d", (optsp[i] & 0x00FF));
printf("%c", (i != optsnr - 1) ? ',' : ' ');
}
}
static void dst_print(const void *ip, const struct xt_entry_match *match,
int numeric)
{
const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data;
printf("dst ");
if (optinfo->flags & IP6T_OPTS_LEN)
printf("length:%s%u ",
optinfo->invflags & IP6T_OPTS_INV_LEN ? "!" : "",
optinfo->hdrlen);
if (optinfo->flags & IP6T_OPTS_OPTS)
printf("opts ");
print_options(optinfo->optsnr, (u_int16_t *)optinfo->opts);
if (optinfo->flags & IP6T_OPTS_NSTRICT)
printf("not-strict ");
if (optinfo->invflags & ~IP6T_OPTS_INV_MASK)
printf("Unknown invflags: 0x%X ",
optinfo->invflags & ~IP6T_OPTS_INV_MASK);
}
static void dst_save(const void *ip, const struct xt_entry_match *match)
{
const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data;
if (optinfo->flags & IP6T_OPTS_LEN) {
printf("%s--dst-len %u ",
(optinfo->invflags & IP6T_OPTS_INV_LEN) ? "! " : "",
optinfo->hdrlen);
}
if (optinfo->flags & IP6T_OPTS_OPTS)
printf("--dst-opts ");
print_options(optinfo->optsnr, (u_int16_t *)optinfo->opts);
if (optinfo->flags & IP6T_OPTS_NSTRICT)
printf("--dst-not-strict ");
}
static struct xtables_match dst_mt6_reg = {
.name = "dst",
.version = XTABLES_VERSION,
.family = NFPROTO_IPV6,
.size = XT_ALIGN(sizeof(struct ip6t_opts)),
.userspacesize = XT_ALIGN(sizeof(struct ip6t_opts)),
.help = dst_help,
.init = dst_init,
.parse = dst_parse,
.print = dst_print,
.save = dst_save,
.extra_opts = dst_opts,
};
void
_init(void)
{
xtables_register_match(&dst_mt6_reg);
}
|
