/* Shared library add-on to iptables for the TTL target
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* (C) 2000 by Harald Welte <laforge@gnumonks.org>
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*
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* This program is distributed under the terms of GNU GPL
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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_ipv4/ipt_TTL.h>
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enum {
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O_TTL_SET = 0,
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O_TTL_INC,
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O_TTL_DEC,
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F_TTL_SET = 1 << O_TTL_SET,
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F_TTL_INC = 1 << O_TTL_INC,
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F_TTL_DEC = 1 << O_TTL_DEC,
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F_ANY = F_TTL_SET | F_TTL_INC | F_TTL_DEC,
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};
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#define s struct ipt_TTL_info
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static const struct xt_option_entry TTL_opts[] = {
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{.name = "ttl-set", .type = XTTYPE_UINT8, .id = O_TTL_SET,
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.excl = F_ANY, .flags = XTOPT_PUT, XTOPT_POINTER(s, ttl)},
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{.name = "ttl-dec", .type = XTTYPE_UINT8, .id = O_TTL_DEC,
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.excl = F_ANY, .flags = XTOPT_PUT, XTOPT_POINTER(s, ttl),
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.min = 1},
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{.name = "ttl-inc", .type = XTTYPE_UINT8, .id = O_TTL_INC,
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.excl = F_ANY, .flags = XTOPT_PUT, XTOPT_POINTER(s, ttl),
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.min = 1},
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XTOPT_TABLEEND,
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};
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#undef s
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static void TTL_help(void)
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{
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printf(
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"TTL target options\n"
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" --ttl-set value Set TTL to <value 0-255>\n"
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" --ttl-dec value Decrement TTL by <value 1-255>\n"
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" --ttl-inc value Increment TTL by <value 1-255>\n");
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}
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static void TTL_parse(struct xt_option_call *cb)
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{
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struct ipt_TTL_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_TTL_SET:
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info->mode = IPT_TTL_SET;
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break;
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case O_TTL_DEC:
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info->mode = IPT_TTL_DEC;
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break;
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case O_TTL_INC:
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info->mode = IPT_TTL_INC;
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break;
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}
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}
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static void TTL_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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"TTL: You must specify an action");
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}
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static void TTL_save(const void *ip, const struct xt_entry_target *target)
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{
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const struct ipt_TTL_info *info =
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(struct ipt_TTL_info *) target->data;
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switch (info->mode) {
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case IPT_TTL_SET:
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printf(" --ttl-set");
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break;
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case IPT_TTL_DEC:
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printf(" --ttl-dec");
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break;
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case IPT_TTL_INC:
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printf(" --ttl-inc");
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break;
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}
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printf(" %u", info->ttl);
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}
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static void TTL_print(const void *ip, const struct xt_entry_target *target,
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int numeric)
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{
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const struct ipt_TTL_info *info =
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(struct ipt_TTL_info *) target->data;
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printf(" TTL ");
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switch (info->mode) {
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case IPT_TTL_SET:
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printf("set to");
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break;
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case IPT_TTL_DEC:
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printf("decrement by");
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break;
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case IPT_TTL_INC:
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printf("increment by");
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break;
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}
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printf(" %u", info->ttl);
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}
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static struct xtables_target ttl_tg_reg = {
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.name = "TTL",
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.version = XTABLES_VERSION,
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.family = NFPROTO_IPV4,
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.size = XT_ALIGN(sizeof(struct ipt_TTL_info)),
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.userspacesize = XT_ALIGN(sizeof(struct ipt_TTL_info)),
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.help = TTL_help,
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.print = TTL_print,
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.save = TTL_save,
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.x6_parse = TTL_parse,
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.x6_fcheck = TTL_check,
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.x6_options = TTL_opts,
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};
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void _init(void)
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{
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xtables_register_target(&ttl_tg_reg);
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}
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