netfilter: Combine ipt_ttl and ip6t_hl source

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>

3 files changed, 117 insertions, 0 deletions

diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index d99f29b7b980..0eb98b4fbf44 100644
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -620,6 +620,14 @@ config NETFILTER_XT_MATCH_HELPER
 
 	  To compile it as a module, choose M here.  If unsure, say Y.
 
+config NETFILTER_XT_MATCH_HL
+	tristate '"hl" hoplimit/TTL match support'
+	depends on NETFILTER_ADVANCED
+	---help---
+	HL matching allows you to match packets based on the hoplimit
+	in the IPv6 header, or the time-to-live field in the IPv4
+	header of the packet.
+
 config NETFILTER_XT_MATCH_IPRANGE
 	tristate '"iprange" address range match support'
 	depends on NETFILTER_ADVANCED
diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
index 6ebe0482265b..da73ed25701c 100644
--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
@@ -68,6 +68,7 @@ obj-$(CONFIG_NETFILTER_XT_MATCH_DSCP) += xt_dscp.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_ESP) += xt_esp.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_HASHLIMIT) += xt_hashlimit.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_HELPER) += xt_helper.o
+obj-$(CONFIG_NETFILTER_XT_MATCH_HL) += xt_hl.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_IPRANGE) += xt_iprange.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_LENGTH) += xt_length.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_LIMIT) += xt_limit.o
diff --git a/net/netfilter/xt_hl.c b/net/netfilter/xt_hl.c
new file mode 100644
index 000000000000..7726154c87b2
--- /dev/null
+++ b/net/netfilter/xt_hl.c
@@ -0,0 +1,108 @@
+/*
+ * IP tables module for matching the value of the TTL
+ * (C) 2000,2001 by Harald Welte <laforge@netfilter.org>
+ *
+ * Hop Limit matching module
+ * (C) 2001-2002 Maciej Soltysiak <solt@dns.toxicfilms.tv>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+
+#include <linux/netfilter/x_tables.h>
+#include <linux/netfilter_ipv4/ipt_ttl.h>
+#include <linux/netfilter_ipv6/ip6t_hl.h>
+
+MODULE_AUTHOR("Maciej Soltysiak <solt@dns.toxicfilms.tv>");
+MODULE_DESCRIPTION("Xtables: Hoplimit/TTL field match");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("ipt_ttl");
+MODULE_ALIAS("ip6t_hl");
+
+static bool ttl_mt(const struct sk_buff *skb, const struct xt_match_param *par)
+{
+	const struct ipt_ttl_info *info = par->matchinfo;
+	const u8 ttl = ip_hdr(skb)->ttl;
+
+	switch (info->mode) {
+		case IPT_TTL_EQ:
+			return ttl == info->ttl;
+		case IPT_TTL_NE:
+			return ttl != info->ttl;
+		case IPT_TTL_LT:
+			return ttl < info->ttl;
+		case IPT_TTL_GT:
+			return ttl > info->ttl;
+		default:
+			printk(KERN_WARNING "ipt_ttl: unknown mode %d\n",
+				info->mode);
+			return false;
+	}
+
+	return false;
+}
+
+static bool hl_mt6(const struct sk_buff *skb, const struct xt_match_param *par)
+{
+	const struct ip6t_hl_info *info = par->matchinfo;
+	const struct ipv6hdr *ip6h = ipv6_hdr(skb);
+
+	switch (info->mode) {
+		case IP6T_HL_EQ:
+			return ip6h->hop_limit == info->hop_limit;
+			break;
+		case IP6T_HL_NE:
+			return ip6h->hop_limit != info->hop_limit;
+			break;
+		case IP6T_HL_LT:
+			return ip6h->hop_limit < info->hop_limit;
+			break;
+		case IP6T_HL_GT:
+			return ip6h->hop_limit > info->hop_limit;
+			break;
+		default:
+			printk(KERN_WARNING "ip6t_hl: unknown mode %d\n",
+				info->mode);
+			return false;
+	}
+
+	return false;
+}
+
+static struct xt_match hl_mt_reg[] __read_mostly = {
+	{
+		.name       = "ttl",
+		.revision   = 0,
+		.family     = NFPROTO_IPV4,
+		.match      = ttl_mt,
+		.matchsize  = sizeof(struct ipt_ttl_info),
+		.me         = THIS_MODULE,
+	},
+	{
+		.name       = "hl",
+		.revision   = 0,
+		.family     = NFPROTO_IPV6,
+		.match      = hl_mt6,
+		.matchsize  = sizeof(struct ip6t_hl_info),
+		.me         = THIS_MODULE,
+	},
+};
+
+static int __init hl_mt_init(void)
+{
+	return xt_register_matches(hl_mt_reg, ARRAY_SIZE(hl_mt_reg));
+}
+
+static void __exit hl_mt_exit(void)
+{
+	xt_unregister_matches(hl_mt_reg, ARRAY_SIZE(hl_mt_reg));
+}
+
+module_init(hl_mt_init);
+module_exit(hl_mt_exit);