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 #include <stdio.h>
8 #include <xtables.h>
9 #include <linux/netfilter_ipv6/ip6t_HL.h>
10
11 enum {
12 O_HL_SET = 0,
13 O_HL_INC,
14 O_HL_DEC,
15 F_HL_SET = 1 << O_HL_SET,
16 F_HL_INC = 1 << O_HL_INC,
17 F_HL_DEC = 1 << O_HL_DEC,
18 F_ANY = F_HL_SET | F_HL_INC | F_HL_DEC,
19 };
20
21 #define s struct ip6t_HL_info
22 static const struct xt_option_entry HL_opts[] = {
23 {.name = "hl-set", .type = XTTYPE_UINT8, .id = O_HL_SET,
24 .excl = F_ANY, .flags = XTOPT_PUT, XTOPT_POINTER(s, hop_limit)},
25 {.name = "hl-dec", .type = XTTYPE_UINT8, .id = O_HL_DEC,
26 .excl = F_ANY, .flags = XTOPT_PUT, XTOPT_POINTER(s, hop_limit),
27 .min = 1},
28 {.name = "hl-inc", .type = XTTYPE_UINT8, .id = O_HL_INC,
29 .excl = F_ANY, .flags = XTOPT_PUT, XTOPT_POINTER(s, hop_limit),
30 .min = 1},
31 XTOPT_TABLEEND,
32 };
33 #undef s
34
HL_help(void)35 static void HL_help(void)
36 {
37 printf(
38 "HL target options\n"
39 " --hl-set value Set HL to <value 0-255>\n"
40 " --hl-dec value Decrement HL by <value 1-255>\n"
41 " --hl-inc value Increment HL by <value 1-255>\n");
42 }
43
HL_parse(struct xt_option_call * cb)44 static void HL_parse(struct xt_option_call *cb)
45 {
46 struct ip6t_HL_info *info = cb->data;
47
48 xtables_option_parse(cb);
49 switch (cb->entry->id) {
50 case O_HL_SET:
51 info->mode = IP6T_HL_SET;
52 break;
53 case O_HL_INC:
54 info->mode = IP6T_HL_INC;
55 break;
56 case O_HL_DEC:
57 info->mode = IP6T_HL_DEC;
58 break;
59 }
60 }
61
HL_check(struct xt_fcheck_call * cb)62 static void HL_check(struct xt_fcheck_call *cb)
63 {
64 if (!(cb->xflags & F_ANY))
65 xtables_error(PARAMETER_PROBLEM,
66 "HL: You must specify an action");
67 }
68
HL_save(const void * ip,const struct xt_entry_target * target)69 static void HL_save(const void *ip, const struct xt_entry_target *target)
70 {
71 const struct ip6t_HL_info *info =
72 (struct ip6t_HL_info *) target->data;
73
74 switch (info->mode) {
75 case IP6T_HL_SET:
76 printf(" --hl-set");
77 break;
78 case IP6T_HL_DEC:
79 printf(" --hl-dec");
80 break;
81
82 case IP6T_HL_INC:
83 printf(" --hl-inc");
84 break;
85 }
86 printf(" %u", info->hop_limit);
87 }
88
HL_print(const void * ip,const struct xt_entry_target * target,int numeric)89 static void HL_print(const void *ip, const struct xt_entry_target *target,
90 int numeric)
91 {
92 const struct ip6t_HL_info *info =
93 (struct ip6t_HL_info *) target->data;
94
95 printf(" HL ");
96 switch (info->mode) {
97 case IP6T_HL_SET:
98 printf("set to");
99 break;
100 case IP6T_HL_DEC:
101 printf("decrement by");
102 break;
103 case IP6T_HL_INC:
104 printf("increment by");
105 break;
106 }
107 printf(" %u", info->hop_limit);
108 }
109
110 static struct xtables_target hl_tg6_reg = {
111 .name = "HL",
112 .version = XTABLES_VERSION,
113 .family = NFPROTO_IPV6,
114 .size = XT_ALIGN(sizeof(struct ip6t_HL_info)),
115 .userspacesize = XT_ALIGN(sizeof(struct ip6t_HL_info)),
116 .help = HL_help,
117 .print = HL_print,
118 .save = HL_save,
119 .x6_parse = HL_parse,
120 .x6_fcheck = HL_check,
121 .x6_options = HL_opts,
122 };
123
_init(void)124 void _init(void)
125 {
126 xtables_register_target(&hl_tg6_reg);
127 }
128