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/*
* IPv6 Hop Limit matching module
* Maciej Soltysiak <solt@dns.toxicfilms.tv>
* Based on HW's ttl match
* This program is released under the terms of GNU GPL
* Cleanups by Stephane Ouellette <ouellettes@videotron.ca>
*/
#include <stdio.h>
#include <xtables.h>
#include <linux/netfilter_ipv6/ip6t_hl.h>
enum {
O_HL_EQ = 0,
O_HL_LT,
O_HL_GT,
F_HL_EQ = 1 << O_HL_EQ,
F_HL_LT = 1 << O_HL_LT,
F_HL_GT = 1 << O_HL_GT,
F_ANY = F_HL_EQ | F_HL_LT | F_HL_GT,
};
static void hl_help(void)
{
printf(
"hl match options:\n"
"[!] --hl-eq value Match hop limit value\n"
" --hl-lt value Match HL < value\n"
" --hl-gt value Match HL > value\n");
}
static void hl_parse(struct xt_option_call *cb)
{
struct ip6t_hl_info *info = cb->data;
xtables_option_parse(cb);
switch (cb->entry->id) {
case O_HL_EQ:
info->mode = cb->invert ? IP6T_HL_NE : IP6T_HL_EQ;
break;
case O_HL_LT:
info->mode = IP6T_HL_LT;
break;
case O_HL_GT:
info->mode = IP6T_HL_GT;
break;
}
}
static void hl_check(struct xt_fcheck_call *cb)
{
if (!(cb->xflags & F_ANY))
xtables_error(PARAMETER_PROBLEM,
"HL match: You must specify one of "
"`--hl-eq', `--hl-lt', `--hl-gt'");
}
static void hl_print(const void *ip, const struct xt_entry_match *match,
int numeric)
{
static const char *const op[] = {
[IP6T_HL_EQ] = "==",
[IP6T_HL_NE] = "!=",
[IP6T_HL_LT] = "<",
[IP6T_HL_GT] = ">" };
const struct ip6t_hl_info *info =
(struct ip6t_hl_info *) match->data;
printf(" HL match HL %s %u", op[info->mode], info->hop_limit);
}
static void hl_save(const void *ip, const struct xt_entry_match *match)
{
static const char *const op[] = {
[IP6T_HL_EQ] = "--hl-eq",
[IP6T_HL_NE] = "! --hl-eq",
[IP6T_HL_LT] = "--hl-lt",
[IP6T_HL_GT] = "--hl-gt" };
const struct ip6t_hl_info *info =
(struct ip6t_hl_info *) match->data;
printf(" %s %u", op[info->mode], info->hop_limit);
}
#define s struct ip6t_hl_info
static const struct xt_option_entry hl_opts[] = {
{.name = "hl-lt", .id = O_HL_LT, .excl = F_ANY, .type = XTTYPE_UINT8,
.flags = XTOPT_PUT, XTOPT_POINTER(s, hop_limit)},
{.name = "hl-gt", .id = O_HL_GT, .excl = F_ANY, .type = XTTYPE_UINT8,
.flags = XTOPT_PUT, XTOPT_POINTER(s, hop_limit)},
{.name = "hl-eq", .id = O_HL_EQ, .excl = F_ANY, .type = XTTYPE_UINT8,
.flags = XTOPT_INVERT | XTOPT_PUT, XTOPT_POINTER(s, hop_limit)},
{.name = "hl", .id = O_HL_EQ, .excl = F_ANY, .type = XTTYPE_UINT8,
.flags = XTOPT_PUT, XTOPT_POINTER(s, hop_limit)},
XTOPT_TABLEEND,
};
#undef s
static struct xtables_match hl_mt6_reg = {
.name = "hl",
.version = XTABLES_VERSION,
.family = NFPROTO_IPV6,
.size = XT_ALIGN(sizeof(struct ip6t_hl_info)),
.userspacesize = XT_ALIGN(sizeof(struct ip6t_hl_info)),
.help = hl_help,
.print = hl_print,
.save = hl_save,
.x6_parse = hl_parse,
.x6_fcheck = hl_check,
.x6_options = hl_opts,
};
void _init(void)
{
xtables_register_match(&hl_mt6_reg);
}
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