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192.168.1.100 / T106_DC / a4ae28ca2232e2054c1f42b4720ffd703bff83d4 / . / ap / app / iptables / extensions / libip6t_HL.c
blob: 12d8e725d5d88381a8b6700b6311df4a6bb0289d [file] [log] [blame]
lh9ed821d2023-04-07 01:36:19 -0700[diff] [blame]1/*
2 * IPv6 Hop Limit Target module
3 * Maciej Soltysiak <solt@dns.toxicfilms.tv>
4 * Based on HW's ttl target
5 * This program is distributed under the terms of GNU GPL
6 */
7
8#include <getopt.h>
9#include <stdio.h>
10#include <string.h>
11#include <stdlib.h>
12#include <xtables.h>
13
14#include <linux/netfilter_ipv6/ip6t_HL.h>
15
16#define IP6T_HL_USED 1
17
18static void HL_help(void)
19{
20 printf(
21"HL target options\n"
22" --hl-set value Set HL to <value 0-255>\n"
23" --hl-dec value Decrement HL by <value 1-255>\n"
24" --hl-inc value Increment HL by <value 1-255>\n");
25}
26
27static int HL_parse(int c, char **argv, int invert, unsigned int *flags,
28 const void *entry, struct xt_entry_target **target)
29{
30 struct ip6t_HL_info *info = (struct ip6t_HL_info *) (*target)->data;
31 unsigned int value;
32
33 if (*flags & IP6T_HL_USED) {
34 xtables_error(PARAMETER_PROBLEM,
35 "Can't specify HL option twice");
36 }
37
38 if (!optarg)
39 xtables_error(PARAMETER_PROBLEM,
40 "HL: You must specify a value");
41
42 if (xtables_check_inverse(optarg, &invert, NULL, 0))
43 xtables_error(PARAMETER_PROBLEM,
44 "HL: unexpected `!'");
45
46 if (!xtables_strtoui(optarg, NULL, &value, 0, UINT8_MAX))
47 xtables_error(PARAMETER_PROBLEM,
48 "HL: Expected value between 0 and 255");
49
50 switch (c) {
51
52 case '1':
53 info->mode = IP6T_HL_SET;
54 break;
55
56 case '2':
57 if (value == 0) {
58 xtables_error(PARAMETER_PROBLEM,
59 "HL: decreasing by 0?");
60 }
61
62 info->mode = IP6T_HL_DEC;
63 break;
64
65 case '3':
66 if (value == 0) {
67 xtables_error(PARAMETER_PROBLEM,
68 "HL: increasing by 0?");
69 }
70
71 info->mode = IP6T_HL_INC;
72 break;
73
74 default:
75 return 0;
76
77 }
78
79 info->hop_limit = value;
80 *flags |= IP6T_HL_USED;
81
82 return 1;
83}
84
85static void HL_check(unsigned int flags)
86{
87 if (!(flags & IP6T_HL_USED))
88 xtables_error(PARAMETER_PROBLEM,
89 "HL: You must specify an action");
90}
91
92static void HL_save(const void *ip, const struct xt_entry_target *target)
93{
94 const struct ip6t_HL_info *info =
95 (struct ip6t_HL_info *) target->data;
96
97 switch (info->mode) {
98 case IP6T_HL_SET:
99 printf("--hl-set ");
100 break;
101 case IP6T_HL_DEC:
102 printf("--hl-dec ");
103 break;
104
105 case IP6T_HL_INC:
106 printf("--hl-inc ");
107 break;
108 }
109 printf("%u ", info->hop_limit);
110}
111
112static void HL_print(const void *ip, const struct xt_entry_target *target,
113 int numeric)
114{
115 const struct ip6t_HL_info *info =
116 (struct ip6t_HL_info *) target->data;
117
118 printf("HL ");
119 switch (info->mode) {
120 case IP6T_HL_SET:
121 printf("set to ");
122 break;
123 case IP6T_HL_DEC:
124 printf("decrement by ");
125 break;
126 case IP6T_HL_INC:
127 printf("increment by ");
128 break;
129 }
130 printf("%u ", info->hop_limit);
131}
132
133static const struct option HL_opts[] = {
134 { "hl-set", 1, NULL, '1' },
135 { "hl-dec", 1, NULL, '2' },
136 { "hl-inc", 1, NULL, '3' },
137 { .name = NULL }
138};
139
140static struct xtables_target hl_tg6_reg = {
141 .name = "HL",
142 .version = XTABLES_VERSION,
143 .family = NFPROTO_IPV6,
144 .size = XT_ALIGN(sizeof(struct ip6t_HL_info)),
145 .userspacesize = XT_ALIGN(sizeof(struct ip6t_HL_info)),
146 .help = HL_help,
147 .parse = HL_parse,
148 .final_check = HL_check,
149 .print = HL_print,
150 .save = HL_save,
151 .extra_opts = HL_opts,
152};
153
154void _init(void)
155{
156 xtables_register_target(&hl_tg6_reg);
157}