1 files changed, 157 insertions, 0 deletions
diff --git a/extensions/libip6t_HL.c b/extensions/libip6t_HL.c
new file mode 100644
index 0000000..bff0611
--- /dev/null
+++ b/extensions/libip6t_HL.c
@@ -0,0 +1,157 @@
+/*
+ * IPv6 Hop Limit Target module
+ * Maciej Soltysiak <solt@dns.toxicfilms.tv>
+ * Based on HW's ttl target
+ * This program is distributed under the terms of GNU GPL
+ */
+
+#include <getopt.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <xtables.h>
+
+#include <linux/netfilter_ipv6/ip6t_HL.h>
+
+#define IP6T_HL_USED	1
+
+static void HL_help(void)
+{
+	printf(
+"HL target options\n"
+"  --hl-set value		Set HL to <value 0-255>\n"
+"  --hl-dec value		Decrement HL by <value 1-255>\n"
+"  --hl-inc value		Increment HL by <value 1-255>\n");
+}
+
+static int HL_parse(int c, char **argv, int invert, unsigned int *flags,
+                    const void *entry, struct xt_entry_target **target)
+{
+	struct ip6t_HL_info *info = (struct ip6t_HL_info *) (*target)->data;
+	unsigned int value;
+
+	if (*flags & IP6T_HL_USED) {
+		xtables_error(PARAMETER_PROBLEM,
+				"Can't specify HL option twice");
+	}
+
+	if (!optarg) 
+		xtables_error(PARAMETER_PROBLEM,
+				"HL: You must specify a value");
+
+	if (xtables_check_inverse(optarg, &invert, NULL, 0, argv))
+		xtables_error(PARAMETER_PROBLEM,
+				"HL: unexpected `!'");
+	
+	if (!xtables_strtoui(optarg, NULL, &value, 0, UINT8_MAX))
+		xtables_error(PARAMETER_PROBLEM,
+		           "HL: Expected value between 0 and 255");
+
+	switch (c) {
+
+		case '1':
+			info->mode = IP6T_HL_SET;
+			break;
+
+		case '2':
+			if (value == 0) {
+				xtables_error(PARAMETER_PROBLEM,
+					"HL: decreasing by 0?");
+			}
+
+			info->mode = IP6T_HL_DEC;
+			break;
+
+		case '3':
+			if (value == 0) {
+				xtables_error(PARAMETER_PROBLEM,
+					"HL: increasing by 0?");
+			}
+
+			info->mode = IP6T_HL_INC;
+			break;
+
+		default:
+			return 0;
+
+	}
+	
+	info->hop_limit = value;
+	*flags |= IP6T_HL_USED;
+
+	return 1;
+}
+
+static void HL_check(unsigned int flags)
+{
+	if (!(flags & IP6T_HL_USED))
+		xtables_error(PARAMETER_PROBLEM,
+				"HL: You must specify an action");
+}
+
+static void HL_save(const void *ip, const struct xt_entry_target *target)
+{
+	const struct ip6t_HL_info *info = 
+		(struct ip6t_HL_info *) target->data;
+
+	switch (info->mode) {
+		case IP6T_HL_SET:
+			printf("--hl-set ");
+			break;
+		case IP6T_HL_DEC:
+			printf("--hl-dec ");
+			break;
+
+		case IP6T_HL_INC:
+			printf("--hl-inc ");
+			break;
+	}
+	printf("%u ", info->hop_limit);
+}
+
+static void HL_print(const void *ip, const struct xt_entry_target *target,
+                     int numeric)
+{
+	const struct ip6t_HL_info *info =
+		(struct ip6t_HL_info *) target->data;
+
+	printf("HL ");
+	switch (info->mode) {
+		case IP6T_HL_SET:
+			printf("set to ");
+			break;
+		case IP6T_HL_DEC:
+			printf("decrement by ");
+			break;
+		case IP6T_HL_INC:
+			printf("increment by ");
+			break;
+	}
+	printf("%u ", info->hop_limit);
+}
+
+static const struct option HL_opts[] = {
+	{ "hl-set", 1, NULL, '1' },
+	{ "hl-dec", 1, NULL, '2' },
+	{ "hl-inc", 1, NULL, '3' },
+	{ .name = NULL }
+};
+
+static struct xtables_target hl_tg6_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_target(&hl_tg6_reg);
+}