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
242
243
244
245
246
247
248
249
250
251
252
|
/* Shared library add-on to ip6tables to add Fragmentation 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_frag.h>
static void frag_help(void)
{
printf(
"frag match options:\n"
"[!] --fragid id[:id] match the id (range)\n"
"[!] --fraglen length total length of this header\n"
" --fragres check the reserved filed, too\n"
" --fragfirst matches on the first fragment\n"
" [--fragmore|--fraglast] there are more fragments or this\n"
" is the last one\n");
}
static const struct option frag_opts[] = {
{ .name = "fragid", .has_arg = 1, .val = '1' },
{ .name = "fraglen", .has_arg = 1, .val = '2' },
{ .name = "fragres", .has_arg = 0, .val = '3' },
{ .name = "fragfirst", .has_arg = 0, .val = '4' },
{ .name = "fragmore", .has_arg = 0, .val = '5' },
{ .name = "fraglast", .has_arg = 0, .val = '6' },
{ .name = NULL }
};
static u_int32_t
parse_frag_id(const char *idstr, const char *typestr)
{
unsigned long int id;
char* ep;
id = strtoul(idstr, &ep, 0);
if ( idstr == ep ) {
xtables_error(PARAMETER_PROBLEM,
"FRAG 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,
"FRAG error parsing %s `%s'", typestr, idstr);
}
return id;
}
static void
parse_frag_ids(const char *idstring, u_int32_t *ids)
{
char *buffer;
char *cp;
buffer = strdup(idstring);
if ((cp = strchr(buffer, ':')) == NULL)
ids[0] = ids[1] = parse_frag_id(buffer,"id");
else {
*cp = '\0';
cp++;
ids[0] = buffer[0] ? parse_frag_id(buffer,"id") : 0;
ids[1] = cp[0] ? parse_frag_id(cp,"id") : 0xFFFFFFFF;
}
free(buffer);
}
static void frag_init(struct xt_entry_match *m)
{
struct ip6t_frag *fraginfo = (struct ip6t_frag *)m->data;
fraginfo->ids[0] = 0x0L;
fraginfo->ids[1] = 0xFFFFFFFF;
fraginfo->hdrlen = 0;
fraginfo->flags = 0;
fraginfo->invflags = 0;
}
static int frag_parse(int c, char **argv, int invert, unsigned int *flags,
const void *entry, struct xt_entry_match **match)
{
struct ip6t_frag *fraginfo = (struct ip6t_frag *)(*match)->data;
switch (c) {
case '1':
if (*flags & IP6T_FRAG_IDS)
xtables_error(PARAMETER_PROBLEM,
"Only one `--fragid' allowed");
xtables_check_inverse(optarg, &invert, &optind, 0, argv);
parse_frag_ids(optarg, fraginfo->ids);
if (invert)
fraginfo->invflags |= IP6T_FRAG_INV_IDS;
fraginfo->flags |= IP6T_FRAG_IDS;
*flags |= IP6T_FRAG_IDS;
break;
case '2':
if (*flags & IP6T_FRAG_LEN)
xtables_error(PARAMETER_PROBLEM,
"Only one `--fraglen' allowed");
xtables_check_inverse(optarg, &invert, &optind, 0, argv);
fraginfo->hdrlen = parse_frag_id(optarg, "length");
if (invert)
fraginfo->invflags |= IP6T_FRAG_INV_LEN;
fraginfo->flags |= IP6T_FRAG_LEN;
*flags |= IP6T_FRAG_LEN;
break;
case '3':
if (*flags & IP6T_FRAG_RES)
xtables_error(PARAMETER_PROBLEM,
"Only one `--fragres' allowed");
fraginfo->flags |= IP6T_FRAG_RES;
*flags |= IP6T_FRAG_RES;
break;
case '4':
if (*flags & IP6T_FRAG_FST)
xtables_error(PARAMETER_PROBLEM,
"Only one `--fragfirst' allowed");
fraginfo->flags |= IP6T_FRAG_FST;
*flags |= IP6T_FRAG_FST;
break;
case '5':
if (*flags & (IP6T_FRAG_MF|IP6T_FRAG_NMF))
xtables_error(PARAMETER_PROBLEM,
"Only one `--fragmore' or `--fraglast' allowed");
fraginfo->flags |= IP6T_FRAG_MF;
*flags |= IP6T_FRAG_MF;
break;
case '6':
if (*flags & (IP6T_FRAG_MF|IP6T_FRAG_NMF))
xtables_error(PARAMETER_PROBLEM,
"Only one `--fragmore' or `--fraglast' allowed");
fraginfo->flags |= IP6T_FRAG_NMF;
*flags |= IP6T_FRAG_NMF;
break;
default:
return 0;
}
return 1;
}
static void
print_ids(const char *name, u_int32_t min, u_int32_t max,
int invert)
{
const char *inv = invert ? "!" : "";
if (min != 0 || max != 0xFFFFFFFF || invert) {
printf("%s", name);
if (min == max)
printf(":%s%u ", inv, min);
else
printf("s:%s%u:%u ", inv, min, max);
}
}
static void frag_print(const void *ip, const struct xt_entry_match *match,
int numeric)
{
const struct ip6t_frag *frag = (struct ip6t_frag *)match->data;
printf("frag ");
print_ids("id", frag->ids[0], frag->ids[1],
frag->invflags & IP6T_FRAG_INV_IDS);
if (frag->flags & IP6T_FRAG_LEN) {
printf("length:%s%u ",
frag->invflags & IP6T_FRAG_INV_LEN ? "!" : "",
frag->hdrlen);
}
if (frag->flags & IP6T_FRAG_RES)
printf("reserved ");
if (frag->flags & IP6T_FRAG_FST)
printf("first ");
if (frag->flags & IP6T_FRAG_MF)
printf("more ");
if (frag->flags & IP6T_FRAG_NMF)
printf("last ");
if (frag->invflags & ~IP6T_FRAG_INV_MASK)
printf("Unknown invflags: 0x%X ",
frag->invflags & ~IP6T_FRAG_INV_MASK);
}
static void frag_save(const void *ip, const struct xt_entry_match *match)
{
const struct ip6t_frag *fraginfo = (struct ip6t_frag *)match->data;
if (!(fraginfo->ids[0] == 0
&& fraginfo->ids[1] == 0xFFFFFFFF)) {
printf("%s--fragid ",
(fraginfo->invflags & IP6T_FRAG_INV_IDS) ? "! " : "");
if (fraginfo->ids[0]
!= fraginfo->ids[1])
printf("%u:%u ",
fraginfo->ids[0],
fraginfo->ids[1]);
else
printf("%u ",
fraginfo->ids[0]);
}
if (fraginfo->flags & IP6T_FRAG_LEN) {
printf("%s--fraglen %u ",
(fraginfo->invflags & IP6T_FRAG_INV_LEN) ? "! " : "",
fraginfo->hdrlen);
}
if (fraginfo->flags & IP6T_FRAG_RES)
printf("--fragres ");
if (fraginfo->flags & IP6T_FRAG_FST)
printf("--fragfirst ");
if (fraginfo->flags & IP6T_FRAG_MF)
printf("--fragmore ");
if (fraginfo->flags & IP6T_FRAG_NMF)
printf("--fraglast ");
}
static struct xtables_match frag_mt6_reg = {
.name = "frag",
.version = XTABLES_VERSION,
.family = NFPROTO_IPV6,
.size = XT_ALIGN(sizeof(struct ip6t_frag)),
.userspacesize = XT_ALIGN(sizeof(struct ip6t_frag)),
.help = frag_help,
.init = frag_init,
.parse = frag_parse,
.print = frag_print,
.save = frag_save,
.extra_opts = frag_opts,
};
void
_init(void)
{
xtables_register_match(&frag_mt6_reg);
}
|
