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138 lines
3.3 KiB
138 lines
3.3 KiB
/*
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* IPv6 Hop Limit matching module
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* Maciej Soltysiak <solt@dns.toxicfilms.tv>
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* Based on HW's ttl match
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* This program is released under the terms of GNU GPL
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* Cleanups by Stephane Ouellette <ouellettes@videotron.ca>
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*/
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#include <stdio.h>
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#include <xtables.h>
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#include <linux/netfilter_ipv6/ip6t_hl.h>
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enum {
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O_HL_EQ = 0,
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O_HL_LT,
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O_HL_GT,
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F_HL_EQ = 1 << O_HL_EQ,
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F_HL_LT = 1 << O_HL_LT,
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F_HL_GT = 1 << O_HL_GT,
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F_ANY = F_HL_EQ | F_HL_LT | F_HL_GT,
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};
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static void hl_help(void)
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{
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printf(
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"hl match options:\n"
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"[!] --hl-eq value Match hop limit value\n"
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" --hl-lt value Match HL < value\n"
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" --hl-gt value Match HL > value\n");
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}
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static void hl_parse(struct xt_option_call *cb)
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{
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struct ip6t_hl_info *info = cb->data;
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xtables_option_parse(cb);
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switch (cb->entry->id) {
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case O_HL_EQ:
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info->mode = cb->invert ? IP6T_HL_NE : IP6T_HL_EQ;
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break;
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case O_HL_LT:
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info->mode = IP6T_HL_LT;
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break;
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case O_HL_GT:
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info->mode = IP6T_HL_GT;
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break;
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}
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}
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static void hl_check(struct xt_fcheck_call *cb)
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{
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if (!(cb->xflags & F_ANY))
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xtables_error(PARAMETER_PROBLEM,
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"HL match: You must specify one of "
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"`--hl-eq', `--hl-lt', `--hl-gt'");
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}
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static void hl_print(const void *ip, const struct xt_entry_match *match,
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int numeric)
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{
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static const char *const op[] = {
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[IP6T_HL_EQ] = "==",
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[IP6T_HL_NE] = "!=",
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[IP6T_HL_LT] = "<",
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[IP6T_HL_GT] = ">" };
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const struct ip6t_hl_info *info =
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(struct ip6t_hl_info *) match->data;
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printf(" HL match HL %s %u", op[info->mode], info->hop_limit);
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}
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static void hl_save(const void *ip, const struct xt_entry_match *match)
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{
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static const char *const op[] = {
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[IP6T_HL_EQ] = "--hl-eq",
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[IP6T_HL_NE] = "! --hl-eq",
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[IP6T_HL_LT] = "--hl-lt",
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[IP6T_HL_GT] = "--hl-gt" };
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const struct ip6t_hl_info *info =
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(struct ip6t_hl_info *) match->data;
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printf(" %s %u", op[info->mode], info->hop_limit);
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}
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static const char *const op[] = {
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[IP6T_HL_EQ] = "",
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[IP6T_HL_NE] = "!= ",
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[IP6T_HL_LT] = "lt ",
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[IP6T_HL_GT] = "gt "
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};
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static int hl_xlate(struct xt_xlate *xl,
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const struct xt_xlate_mt_params *params)
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{
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const struct ip6t_hl_info *info =
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(struct ip6t_hl_info *) params->match->data;
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xt_xlate_add(xl, "ip6 hoplimit %s%u", op[info->mode], info->hop_limit);
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return 1;
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}
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#define s struct ip6t_hl_info
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static const struct xt_option_entry hl_opts[] = {
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{.name = "hl-lt", .id = O_HL_LT, .excl = F_ANY, .type = XTTYPE_UINT8,
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.flags = XTOPT_PUT, XTOPT_POINTER(s, hop_limit)},
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{.name = "hl-gt", .id = O_HL_GT, .excl = F_ANY, .type = XTTYPE_UINT8,
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.flags = XTOPT_PUT, XTOPT_POINTER(s, hop_limit)},
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{.name = "hl-eq", .id = O_HL_EQ, .excl = F_ANY, .type = XTTYPE_UINT8,
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.flags = XTOPT_INVERT | XTOPT_PUT, XTOPT_POINTER(s, hop_limit)},
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{.name = "hl", .id = O_HL_EQ, .excl = F_ANY, .type = XTTYPE_UINT8,
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.flags = XTOPT_PUT, XTOPT_POINTER(s, hop_limit)},
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XTOPT_TABLEEND,
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};
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#undef s
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static struct xtables_match hl_mt6_reg = {
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.name = "hl",
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.version = XTABLES_VERSION,
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.family = NFPROTO_IPV6,
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.size = XT_ALIGN(sizeof(struct ip6t_hl_info)),
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.userspacesize = XT_ALIGN(sizeof(struct ip6t_hl_info)),
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.help = hl_help,
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.print = hl_print,
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.save = hl_save,
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.x6_parse = hl_parse,
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.x6_fcheck = hl_check,
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.x6_options = hl_opts,
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.xlate = hl_xlate,
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};
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void _init(void)
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{
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xtables_register_match(&hl_mt6_reg);
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}
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