1 files changed, 144 insertions, 0 deletions
diff --git a/extensions/libip6t_hl.c b/extensions/libip6t_hl.c
new file mode 100644
index 0000000..09589b1
--- /dev/null
+++ b/extensions/libip6t_hl.c
@@ -0,0 +1,144 @@
+/*
+ * 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 <stdlib.h>
+#include <string.h>
+#include <getopt.h>
+#include <xtables.h>
+
+#include <linux/netfilter_ipv6/ip6t_hl.h>
+
+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 int hl_parse(int c, char **argv, int invert, unsigned int *flags,
+                    const void *entry, struct xt_entry_match **match)
+{
+	struct ip6t_hl_info *info = (struct ip6t_hl_info *) (*match)->data;
+	u_int8_t value;
+
+	xtables_check_inverse(optarg, &invert, &optind, 0, argv);
+	value = atoi(optarg);
+
+	if (*flags) 
+		xtables_error(PARAMETER_PROBLEM,
+				"Can't specify HL option twice");
+
+	if (!optarg)
+		xtables_error(PARAMETER_PROBLEM,
+				"hl: You must specify a value");
+	switch (c) {
+		case '2':
+			if (invert)
+				info->mode = IP6T_HL_NE;
+			else
+				info->mode = IP6T_HL_EQ;
+
+			/* is 0 allowed? */
+			info->hop_limit = value;
+			*flags = 1;
+
+			break;
+		case '3':
+			if (invert) 
+				xtables_error(PARAMETER_PROBLEM,
+						"hl: unexpected `!'");
+
+			info->mode = IP6T_HL_LT;
+			info->hop_limit = value;
+			*flags = 1;
+
+			break;
+		case '4':
+			if (invert)
+				xtables_error(PARAMETER_PROBLEM,
+						"hl: unexpected `!'");
+
+			info->mode = IP6T_HL_GT;
+			info->hop_limit = value;
+			*flags = 1;
+
+			break;
+		default:
+			return 0;
+	}
+
+	return 1;
+}
+
+static void hl_check(unsigned int flags)
+{
+	if (!flags) 
+		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);
+}
+
+static const struct option hl_opts[] = {
+	{ .name = "hl",    .has_arg = 1, .val = '2' },
+	{ .name = "hl-eq", .has_arg = 1, .val = '2' },
+	{ .name = "hl-lt", .has_arg = 1, .val = '3' },
+	{ .name = "hl-gt", .has_arg = 1, .val = '4' },
+	{ .name = NULL }
+};
+
+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,
+	.parse         = hl_parse,
+	.final_check   = hl_check,
+	.print         = hl_print,
+	.save          = hl_save,
+	.extra_opts    = hl_opts,
+};
+
+
+void _init(void) 
+{
+	xtables_register_match(&hl_mt6_reg);
+}