cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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xt_hl.c (2181B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * IP tables module for matching the value of the TTL
      4 * (C) 2000,2001 by Harald Welte <laforge@netfilter.org>
      5 *
      6 * Hop Limit matching module
      7 * (C) 2001-2002 Maciej Soltysiak <solt@dns.toxicfilms.tv>
      8 */
      9
     10#include <linux/ip.h>
     11#include <linux/ipv6.h>
     12#include <linux/module.h>
     13#include <linux/skbuff.h>
     14
     15#include <linux/netfilter/x_tables.h>
     16#include <linux/netfilter_ipv4/ipt_ttl.h>
     17#include <linux/netfilter_ipv6/ip6t_hl.h>
     18
     19MODULE_AUTHOR("Maciej Soltysiak <solt@dns.toxicfilms.tv>");
     20MODULE_DESCRIPTION("Xtables: Hoplimit/TTL field match");
     21MODULE_LICENSE("GPL");
     22MODULE_ALIAS("ipt_ttl");
     23MODULE_ALIAS("ip6t_hl");
     24
     25static bool ttl_mt(const struct sk_buff *skb, struct xt_action_param *par)
     26{
     27	const struct ipt_ttl_info *info = par->matchinfo;
     28	const u8 ttl = ip_hdr(skb)->ttl;
     29
     30	switch (info->mode) {
     31	case IPT_TTL_EQ:
     32		return ttl == info->ttl;
     33	case IPT_TTL_NE:
     34		return ttl != info->ttl;
     35	case IPT_TTL_LT:
     36		return ttl < info->ttl;
     37	case IPT_TTL_GT:
     38		return ttl > info->ttl;
     39	}
     40
     41	return false;
     42}
     43
     44static bool hl_mt6(const struct sk_buff *skb, struct xt_action_param *par)
     45{
     46	const struct ip6t_hl_info *info = par->matchinfo;
     47	const struct ipv6hdr *ip6h = ipv6_hdr(skb);
     48
     49	switch (info->mode) {
     50	case IP6T_HL_EQ:
     51		return ip6h->hop_limit == info->hop_limit;
     52	case IP6T_HL_NE:
     53		return ip6h->hop_limit != info->hop_limit;
     54	case IP6T_HL_LT:
     55		return ip6h->hop_limit < info->hop_limit;
     56	case IP6T_HL_GT:
     57		return ip6h->hop_limit > info->hop_limit;
     58	}
     59
     60	return false;
     61}
     62
     63static struct xt_match hl_mt_reg[] __read_mostly = {
     64	{
     65		.name       = "ttl",
     66		.revision   = 0,
     67		.family     = NFPROTO_IPV4,
     68		.match      = ttl_mt,
     69		.matchsize  = sizeof(struct ipt_ttl_info),
     70		.me         = THIS_MODULE,
     71	},
     72	{
     73		.name       = "hl",
     74		.revision   = 0,
     75		.family     = NFPROTO_IPV6,
     76		.match      = hl_mt6,
     77		.matchsize  = sizeof(struct ip6t_hl_info),
     78		.me         = THIS_MODULE,
     79	},
     80};
     81
     82static int __init hl_mt_init(void)
     83{
     84	return xt_register_matches(hl_mt_reg, ARRAY_SIZE(hl_mt_reg));
     85}
     86
     87static void __exit hl_mt_exit(void)
     88{
     89	xt_unregister_matches(hl_mt_reg, ARRAY_SIZE(hl_mt_reg));
     90}
     91
     92module_init(hl_mt_init);
     93module_exit(hl_mt_exit);