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
|
/*
* Copyright (c) 2011 Patrick McHardy <kaber@trash.net>
*
* Based on Rusty Russell's IPv4 SNAT target. Development of IPv6 NAT
* funded by Astaro.
*/
#include <stdio.h>
#include <netdb.h>
#include <string.h>
#include <stdlib.h>
#include <xtables.h>
#include <iptables.h>
#include <limits.h> /* INT_MAX in ip_tables.h */
#include <linux/netfilter_ipv6/ip6_tables.h>
#include <linux/netfilter/nf_nat.h>
enum {
O_TO_SRC = 0,
O_RANDOM,
O_PERSISTENT,
O_X_TO_SRC,
F_TO_SRC = 1 << O_TO_SRC,
F_RANDOM = 1 << O_RANDOM,
F_X_TO_SRC = 1 << O_X_TO_SRC,
};
static void SNAT_help(void)
{
printf(
"SNAT target options:\n"
" --to-source [<ipaddr>[-<ipaddr>]][:port[-port]]\n"
" Address to map source to.\n"
"[--random] [--persistent]\n");
}
static const struct xt_option_entry SNAT_opts[] = {
{.name = "to-source", .id = O_TO_SRC, .type = XTTYPE_STRING,
.flags = XTOPT_MAND | XTOPT_MULTI},
{.name = "random", .id = O_RANDOM, .type = XTTYPE_NONE},
{.name = "persistent", .id = O_PERSISTENT, .type = XTTYPE_NONE},
XTOPT_TABLEEND,
};
/* Ranges expected in network order. */
static void
parse_to(const char *orig_arg, int portok, struct nf_nat_range *range)
{
char *arg, *start, *end = NULL, *colon = NULL, *dash, *error;
const struct in6_addr *ip;
arg = strdup(orig_arg);
if (arg == NULL)
xtables_error(RESOURCE_PROBLEM, "strdup");
start = strchr(arg, '[');
if (start == NULL) {
start = arg;
/* Lets assume one colon is port information. Otherwise its an IPv6 address */
colon = strchr(arg, ':');
if (colon && strchr(colon+1, ':'))
colon = NULL;
}
else {
start++;
end = strchr(start, ']');
if (end == NULL)
xtables_error(PARAMETER_PROBLEM,
"Invalid address format");
*end = '\0';
colon = strchr(end + 1, ':');
}
if (colon) {
int port;
if (!portok)
xtables_error(PARAMETER_PROBLEM,
"Need TCP, UDP, SCTP or DCCP with port specification");
range->flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
port = atoi(colon+1);
if (port <= 0 || port > 65535)
xtables_error(PARAMETER_PROBLEM,
"Port `%s' not valid\n", colon+1);
error = strchr(colon+1, ':');
if (error)
xtables_error(PARAMETER_PROBLEM,
"Invalid port:port syntax - use dash\n");
dash = strchr(colon, '-');
if (!dash) {
range->min_proto.tcp.port
= range->max_proto.tcp.port
= htons(port);
} else {
int maxport;
maxport = atoi(dash + 1);
if (maxport <= 0 || maxport > 65535)
xtables_error(PARAMETER_PROBLEM,
"Port `%s' not valid\n", dash+1);
if (maxport < port)
/* People are stupid. */
xtables_error(PARAMETER_PROBLEM,
"Port range `%s' funky\n", colon+1);
range->min_proto.tcp.port = htons(port);
range->max_proto.tcp.port = htons(maxport);
}
/* Starts with colon or [] colon? No IP info...*/
if (colon == arg || colon == arg+2) {
free(arg);
return;
}
*colon = '\0';
}
range->flags |= NF_NAT_RANGE_MAP_IPS;
dash = strchr(start, '-');
if (colon && dash && dash > colon)
dash = NULL;
if (dash)
*dash = '\0';
ip = xtables_numeric_to_ip6addr(start);
if (!ip)
xtables_error(PARAMETER_PROBLEM, "Bad IP address \"%s\"\n",
start);
range->min_addr.in6 = *ip;
if (dash) {
ip = xtables_numeric_to_ip6addr(dash + 1);
if (!ip)
xtables_error(PARAMETER_PROBLEM, "Bad IP address \"%s\"\n",
dash+1);
range->max_addr.in6 = *ip;
} else
range->max_addr = range->min_addr;
free(arg);
return;
}
static void SNAT_parse(struct xt_option_call *cb)
{
const struct ip6t_entry *entry = cb->xt_entry;
struct nf_nat_range *range = cb->data;
int portok;
if (entry->ipv6.proto == IPPROTO_TCP ||
entry->ipv6.proto == IPPROTO_UDP ||
entry->ipv6.proto == IPPROTO_SCTP ||
entry->ipv6.proto == IPPROTO_DCCP ||
entry->ipv6.proto == IPPROTO_ICMP)
portok = 1;
else
portok = 0;
xtables_option_parse(cb);
switch (cb->entry->id) {
case O_TO_SRC:
if (cb->xflags & F_X_TO_SRC) {
if (!kernel_version)
get_kernel_version();
if (kernel_version > LINUX_VERSION(2, 6, 10))
xtables_error(PARAMETER_PROBLEM,
"SNAT: Multiple --to-source not supported");
}
parse_to(cb->arg, portok, range);
break;
case O_PERSISTENT:
range->flags |= NF_NAT_RANGE_PERSISTENT;
break;
}
}
static void SNAT_fcheck(struct xt_fcheck_call *cb)
{
static const unsigned int f = F_TO_SRC | F_RANDOM;
struct nf_nat_range *range = cb->data;
if ((cb->xflags & f) == f)
range->flags |= NF_NAT_RANGE_PROTO_RANDOM;
}
static void print_range(const struct nf_nat_range *range)
{
if (range->flags & NF_NAT_RANGE_MAP_IPS) {
if (range->flags & NF_NAT_RANGE_PROTO_SPECIFIED)
printf("[");
printf("%s", xtables_ip6addr_to_numeric(&range->min_addr.in6));
if (memcmp(&range->min_addr, &range->max_addr,
sizeof(range->min_addr)))
printf("-%s", xtables_ip6addr_to_numeric(&range->max_addr.in6));
if (range->flags & NF_NAT_RANGE_PROTO_SPECIFIED)
printf("]");
}
if (range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) {
printf(":");
printf("%hu", ntohs(range->min_proto.tcp.port));
if (range->max_proto.tcp.port != range->min_proto.tcp.port)
printf("-%hu", ntohs(range->max_proto.tcp.port));
}
}
static void SNAT_print(const void *ip, const struct xt_entry_target *target,
int numeric)
{
const struct nf_nat_range *range = (const void *)target->data;
printf(" to:");
print_range(range);
if (range->flags & NF_NAT_RANGE_PROTO_RANDOM)
printf(" random");
if (range->flags & NF_NAT_RANGE_PERSISTENT)
printf(" persistent");
}
static void SNAT_save(const void *ip, const struct xt_entry_target *target)
{
const struct nf_nat_range *range = (const void *)target->data;
printf(" --to-source ");
print_range(range);
if (range->flags & NF_NAT_RANGE_PROTO_RANDOM)
printf(" --random");
if (range->flags & NF_NAT_RANGE_PERSISTENT)
printf(" --persistent");
}
static struct xtables_target snat_tg_reg = {
.name = "SNAT",
.version = XTABLES_VERSION,
.family = NFPROTO_IPV6,
.revision = 1,
.size = XT_ALIGN(sizeof(struct nf_nat_range)),
.userspacesize = XT_ALIGN(sizeof(struct nf_nat_range)),
.help = SNAT_help,
.x6_parse = SNAT_parse,
.x6_fcheck = SNAT_fcheck,
.print = SNAT_print,
.save = SNAT_save,
.x6_options = SNAT_opts,
};
void _init(void)
{
xtables_register_target(&snat_tg_reg);
}
|
