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@@ -0,0 +1,108 @@
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+/*
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+ * IP tables module for matching the value of the TTL
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+ * (C) 2000,2001 by Harald Welte <laforge@netfilter.org>
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+ *
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+ * Hop Limit matching module
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+ * (C) 2001-2002 Maciej Soltysiak <solt@dns.toxicfilms.tv>
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+ *
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+ * This program is free software; you can redistribute it and/or modify
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+ * it under the terms of the GNU General Public License version 2 as
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+ * published by the Free Software Foundation.
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+ */
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+
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+#include <linux/ip.h>
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+#include <linux/ipv6.h>
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+#include <linux/module.h>
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+#include <linux/skbuff.h>
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+
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+#include <linux/netfilter/x_tables.h>
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+#include <linux/netfilter_ipv4/ipt_ttl.h>
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+#include <linux/netfilter_ipv6/ip6t_hl.h>
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+
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+MODULE_AUTHOR("Maciej Soltysiak <solt@dns.toxicfilms.tv>");
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+MODULE_DESCRIPTION("Xtables: Hoplimit/TTL field match");
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+MODULE_LICENSE("GPL");
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+MODULE_ALIAS("ipt_ttl");
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+MODULE_ALIAS("ip6t_hl");
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+
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+static bool ttl_mt(const struct sk_buff *skb, const struct xt_match_param *par)
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+{
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+ const struct ipt_ttl_info *info = par->matchinfo;
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+ const u8 ttl = ip_hdr(skb)->ttl;
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+
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+ switch (info->mode) {
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+ case IPT_TTL_EQ:
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+ return ttl == info->ttl;
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+ case IPT_TTL_NE:
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+ return ttl != info->ttl;
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+ case IPT_TTL_LT:
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+ return ttl < info->ttl;
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+ case IPT_TTL_GT:
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+ return ttl > info->ttl;
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+ default:
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+ printk(KERN_WARNING "ipt_ttl: unknown mode %d\n",
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+ info->mode);
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+ return false;
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+ }
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+
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+ return false;
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+}
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+
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+static bool hl_mt6(const struct sk_buff *skb, const struct xt_match_param *par)
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+{
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+ const struct ip6t_hl_info *info = par->matchinfo;
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+ const struct ipv6hdr *ip6h = ipv6_hdr(skb);
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+
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+ switch (info->mode) {
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+ case IP6T_HL_EQ:
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+ return ip6h->hop_limit == info->hop_limit;
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+ break;
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+ case IP6T_HL_NE:
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+ return ip6h->hop_limit != info->hop_limit;
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+ break;
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+ case IP6T_HL_LT:
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+ return ip6h->hop_limit < info->hop_limit;
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+ break;
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+ case IP6T_HL_GT:
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+ return ip6h->hop_limit > info->hop_limit;
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+ break;
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+ default:
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+ printk(KERN_WARNING "ip6t_hl: unknown mode %d\n",
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+ info->mode);
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+ return false;
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+ }
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+
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+ return false;
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+}
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+
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+static struct xt_match hl_mt_reg[] __read_mostly = {
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+ {
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+ .name = "ttl",
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+ .revision = 0,
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+ .family = NFPROTO_IPV4,
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+ .match = ttl_mt,
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+ .matchsize = sizeof(struct ipt_ttl_info),
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+ .me = THIS_MODULE,
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+ },
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+ {
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+ .name = "hl",
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+ .revision = 0,
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+ .family = NFPROTO_IPV6,
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+ .match = hl_mt6,
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+ .matchsize = sizeof(struct ip6t_hl_info),
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+ .me = THIS_MODULE,
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+ },
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+};
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+
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+static int __init hl_mt_init(void)
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+{
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+ return xt_register_matches(hl_mt_reg, ARRAY_SIZE(hl_mt_reg));
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+}
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+
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+static void __exit hl_mt_exit(void)
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+{
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+ xt_unregister_matches(hl_mt_reg, ARRAY_SIZE(hl_mt_reg));
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+}
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+
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+module_init(hl_mt_init);
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+module_exit(hl_mt_exit);
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Jan Engelhardt