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
|
/*
* Copyright (c) 2011 Patrick McHardy <kaber@trash.net>
*
* Based on Rusty Russell's IPv4 REDIRECT target. Development of IPv6 NAT
* funded by Astaro.
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <xtables.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_PORTS = 0,
O_RANDOM,
F_TO_PORTS = 1 << O_TO_PORTS,
F_RANDOM = 1 << O_RANDOM,
};
static void REDIRECT_help(void)
{
printf(
"REDIRECT target options:\n"
" --to-ports <port>[-<port>]\n"
" Port (range) to map to.\n"
" [--random]\n");
}
static const struct xt_option_entry REDIRECT_opts[] = {
{.name = "to-ports", .id = O_TO_PORTS, .type = XTTYPE_STRING},
{.name = "random", .id = O_RANDOM, .type = XTTYPE_NONE},
XTOPT_TABLEEND,
};
/* Parses ports */
static void
parse_ports(const char *arg, struct nf_nat_range *range)
{
char *end = "";
unsigned int port, maxport;
range->flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
if (!xtables_strtoui(arg, &end, &port, 0, UINT16_MAX) &&
(port = xtables_service_to_port(arg, NULL)) == (unsigned)-1)
xtables_param_act(XTF_BAD_VALUE, "REDIRECT", "--to-ports", arg);
switch (*end) {
case '\0':
range->min_proto.tcp.port
= range->max_proto.tcp.port
= htons(port);
return;
case '-':
if (!xtables_strtoui(end + 1, NULL, &maxport, 0, UINT16_MAX) &&
(maxport = xtables_service_to_port(end + 1, NULL)) == (unsigned)-1)
break;
if (maxport < port)
break;
range->min_proto.tcp.port = htons(port);
range->max_proto.tcp.port = htons(maxport);
return;
default:
break;
}
xtables_param_act(XTF_BAD_VALUE, "REDIRECT", "--to-ports", arg);
}
static void REDIRECT_parse(struct xt_option_call *cb)
{
const struct ip6t_entry *entry = cb->xt_entry;
struct nf_nat_range *range = (void *)(*cb->target)->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_PORTS:
if (!portok)
xtables_error(PARAMETER_PROBLEM,
"Need TCP, UDP, SCTP or DCCP with port specification");
parse_ports(cb->arg, range);
if (cb->xflags & F_RANDOM)
range->flags |= NF_NAT_RANGE_PROTO_RANDOM;
break;
case O_RANDOM:
if (cb->xflags & F_TO_PORTS)
range->flags |= NF_NAT_RANGE_PROTO_RANDOM;
break;
}
}
static void REDIRECT_print(const void *ip, const struct xt_entry_target *target,
int numeric)
{
const struct nf_nat_range *range = (const void *)target->data;
if (range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) {
printf(" redir ports ");
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));
if (range->flags & NF_NAT_RANGE_PROTO_RANDOM)
printf(" random");
}
}
static void REDIRECT_save(const void *ip, const struct xt_entry_target *target)
{
const struct nf_nat_range *range = (const void *)target->data;
if (range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) {
printf(" --to-ports ");
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));
if (range->flags & NF_NAT_RANGE_PROTO_RANDOM)
printf(" --random");
}
}
static struct xtables_target redirect_tg_reg = {
.name = "REDIRECT",
.version = XTABLES_VERSION,
.family = NFPROTO_IPV6,
.size = XT_ALIGN(sizeof(struct nf_nat_range)),
.userspacesize = XT_ALIGN(sizeof(struct nf_nat_range)),
.help = REDIRECT_help,
.x6_parse = REDIRECT_parse,
.print = REDIRECT_print,
.save = REDIRECT_save,
.x6_options = REDIRECT_opts,
};
void _init(void)
{
xtables_register_target(&redirect_tg_reg);
}
|
