1/*
2 * IPv6 Hop Limit matching module
3 * Maciej Soltysiak <solt@dns.toxicfilms.tv>
4 * Based on HW's ttl match
5 * This program is released under the terms of GNU GPL
6 * Cleanups by Stephane Ouellette <ouellettes@videotron.ca>
7 */
8#include <stdio.h>
9#include <xtables.h>
10#include <linux/netfilter_ipv6/ip6t_hl.h>
11
12enum {
13	O_HL_EQ = 0,
14	O_HL_LT,
15	O_HL_GT,
16	F_HL_EQ = 1 << O_HL_EQ,
17	F_HL_LT = 1 << O_HL_LT,
18	F_HL_GT = 1 << O_HL_GT,
19	F_ANY  = F_HL_EQ | F_HL_LT | F_HL_GT,
20};
21
22static void hl_help(void)
23{
24	printf(
25"hl match options:\n"
26"[!] --hl-eq value	Match hop limit value\n"
27"  --hl-lt value	Match HL < value\n"
28"  --hl-gt value	Match HL > value\n");
29}
30
31static void hl_parse(struct xt_option_call *cb)
32{
33	struct ip6t_hl_info *info = cb->data;
34
35	xtables_option_parse(cb);
36	switch (cb->entry->id) {
37	case O_HL_EQ:
38		info->mode = cb->invert ? IP6T_HL_NE : IP6T_HL_EQ;
39		break;
40	case O_HL_LT:
41		info->mode = IP6T_HL_LT;
42		break;
43	case O_HL_GT:
44		info->mode = IP6T_HL_GT;
45		break;
46	}
47}
48
49static void hl_check(struct xt_fcheck_call *cb)
50{
51	if (!(cb->xflags & F_ANY))
52		xtables_error(PARAMETER_PROBLEM,
53			"HL match: You must specify one of "
54			"`--hl-eq', `--hl-lt', `--hl-gt'");
55}
56
57static void hl_print(const void *ip, const struct xt_entry_match *match,
58                     int numeric)
59{
60	static const char *const op[] = {
61		[IP6T_HL_EQ] = "==",
62		[IP6T_HL_NE] = "!=",
63		[IP6T_HL_LT] = "<",
64		[IP6T_HL_GT] = ">" };
65
66	const struct ip6t_hl_info *info =
67		(struct ip6t_hl_info *) match->data;
68
69	printf(" HL match HL %s %u", op[info->mode], info->hop_limit);
70}
71
72static void hl_save(const void *ip, const struct xt_entry_match *match)
73{
74	static const char *const op[] = {
75		[IP6T_HL_EQ] = "--hl-eq",
76		[IP6T_HL_NE] = "! --hl-eq",
77		[IP6T_HL_LT] = "--hl-lt",
78		[IP6T_HL_GT] = "--hl-gt" };
79
80	const struct ip6t_hl_info *info =
81		(struct ip6t_hl_info *) match->data;
82
83	printf(" %s %u", op[info->mode], info->hop_limit);
84}
85
86#define s struct ip6t_hl_info
87static const struct xt_option_entry hl_opts[] = {
88	{.name = "hl-lt", .id = O_HL_LT, .excl = F_ANY, .type = XTTYPE_UINT8,
89	 .flags = XTOPT_PUT, XTOPT_POINTER(s, hop_limit)},
90	{.name = "hl-gt", .id = O_HL_GT, .excl = F_ANY, .type = XTTYPE_UINT8,
91	 .flags = XTOPT_PUT, XTOPT_POINTER(s, hop_limit)},
92	{.name = "hl-eq", .id = O_HL_EQ, .excl = F_ANY, .type = XTTYPE_UINT8,
93	 .flags = XTOPT_INVERT | XTOPT_PUT, XTOPT_POINTER(s, hop_limit)},
94	{.name = "hl", .id = O_HL_EQ, .excl = F_ANY, .type = XTTYPE_UINT8,
95	 .flags = XTOPT_PUT, XTOPT_POINTER(s, hop_limit)},
96	XTOPT_TABLEEND,
97};
98#undef s
99
100static struct xtables_match hl_mt6_reg = {
101	.name          = "hl",
102	.version       = XTABLES_VERSION,
103	.family        = NFPROTO_IPV6,
104	.size          = XT_ALIGN(sizeof(struct ip6t_hl_info)),
105	.userspacesize = XT_ALIGN(sizeof(struct ip6t_hl_info)),
106	.help          = hl_help,
107	.print         = hl_print,
108	.save          = hl_save,
109	.x6_parse      = hl_parse,
110	.x6_fcheck     = hl_check,
111	.x6_options    = hl_opts,
112};
113
114
115void _init(void)
116{
117	xtables_register_match(&hl_mt6_reg);
118}
119