1 files changed, 118 insertions, 0 deletions
diff --git a/extensions/libip6t_hl.c b/extensions/libip6t_hl.c
new file mode 100644
index 00000000..3559db46
--- /dev/null
+++ b/extensions/libip6t_hl.c
@@ -0,0 +1,118 @@
+/*
+ * IPv6 Hop Limit matching module
+ * Maciej Soltysiak <solt@dns.toxicfilms.tv>
+ * Based on HW's ttl match
+ * This program is released under the terms of GNU GPL
+ * Cleanups by Stephane Ouellette <ouellettes@videotron.ca>
+ */
+#include <stdio.h>
+#include <xtables.h>
+#include <linux/netfilter_ipv6/ip6t_hl.h>
+
+enum {
+	O_HL_EQ = 0,
+	O_HL_LT,
+	O_HL_GT,
+	F_HL_EQ = 1 << O_HL_EQ,
+	F_HL_LT = 1 << O_HL_LT,
+	F_HL_GT = 1 << O_HL_GT,
+	F_ANY  = F_HL_EQ | F_HL_LT | F_HL_GT,
+};
+
+static void hl_help(void)
+{
+	printf(
+"hl match options:\n"
+"[!] --hl-eq value	Match hop limit value\n"
+"  --hl-lt value	Match HL < value\n"
+"  --hl-gt value	Match HL > value\n");
+}
+
+static void hl_parse(struct xt_option_call *cb)
+{
+	struct ip6t_hl_info *info = cb->data;
+
+	xtables_option_parse(cb);
+	switch (cb->entry->id) {
+	case O_HL_EQ:
+		info->mode = cb->invert ? IP6T_HL_NE : IP6T_HL_EQ;
+		break;
+	case O_HL_LT:
+		info->mode = IP6T_HL_LT;
+		break;
+	case O_HL_GT:
+		info->mode = IP6T_HL_GT;
+		break;
+	}
+}
+
+static void hl_check(struct xt_fcheck_call *cb)
+{
+	if (!(cb->xflags & F_ANY))
+		xtables_error(PARAMETER_PROBLEM,
+			"HL match: You must specify one of "
+			"`--hl-eq', `--hl-lt', `--hl-gt'");
+}
+
+static void hl_print(const void *ip, const struct xt_entry_match *match,
+                     int numeric)
+{
+	static const char *const op[] = {
+		[IP6T_HL_EQ] = "==",
+		[IP6T_HL_NE] = "!=",
+		[IP6T_HL_LT] = "<",
+		[IP6T_HL_GT] = ">" };
+
+	const struct ip6t_hl_info *info = 
+		(struct ip6t_hl_info *) match->data;
+
+	printf(" HL match HL %s %u", op[info->mode], info->hop_limit);
+}
+
+static void hl_save(const void *ip, const struct xt_entry_match *match)
+{
+	static const char *const op[] = {
+		[IP6T_HL_EQ] = "--hl-eq",
+		[IP6T_HL_NE] = "! --hl-eq",
+		[IP6T_HL_LT] = "--hl-lt",
+		[IP6T_HL_GT] = "--hl-gt" };
+
+	const struct ip6t_hl_info *info =
+		(struct ip6t_hl_info *) match->data;
+
+	printf(" %s %u", op[info->mode], info->hop_limit);
+}
+
+#define s struct ip6t_hl_info
+static const struct xt_option_entry hl_opts[] = {
+	{.name = "hl-lt", .id = O_HL_LT, .excl = F_ANY, .type = XTTYPE_UINT8,
+	 .flags = XTOPT_PUT, XTOPT_POINTER(s, hop_limit)},
+	{.name = "hl-gt", .id = O_HL_GT, .excl = F_ANY, .type = XTTYPE_UINT8,
+	 .flags = XTOPT_PUT, XTOPT_POINTER(s, hop_limit)},
+	{.name = "hl-eq", .id = O_HL_EQ, .excl = F_ANY, .type = XTTYPE_UINT8,
+	 .flags = XTOPT_INVERT | XTOPT_PUT, XTOPT_POINTER(s, hop_limit)},
+	{.name = "hl", .id = O_HL_EQ, .excl = F_ANY, .type = XTTYPE_UINT8,
+	 .flags = XTOPT_PUT, XTOPT_POINTER(s, hop_limit)},
+	XTOPT_TABLEEND,
+};
+#undef s
+
+static struct xtables_match hl_mt6_reg = {
+	.name          = "hl",
+	.version       = XTABLES_VERSION,
+	.family        = NFPROTO_IPV6,
+	.size          = XT_ALIGN(sizeof(struct ip6t_hl_info)),
+	.userspacesize = XT_ALIGN(sizeof(struct ip6t_hl_info)),
+	.help          = hl_help,
+	.print         = hl_print,
+	.save          = hl_save,
+	.x6_parse      = hl_parse,
+	.x6_fcheck     = hl_check,
+	.x6_options    = hl_opts,
+};
+
+
+void _init(void) 
+{
+	xtables_register_match(&hl_mt6_reg);
+}