Git init

1 files changed, 167 insertions, 0 deletions

diff --git a/extensions/libipt_ttl.c b/extensions/libipt_ttl.c
new file mode 100644
index 0000000..e2fbcd5
--- /dev/null
+++ b/extensions/libipt_ttl.c
@@ -0,0 +1,167 @@
+/* Shared library add-on to iptables to add TTL matching support 
+ * (C) 2000 by Harald Welte <laforge@gnumonks.org>
+ *
+ * $Id$
+ *
+ * This program is released under the terms of GNU GPL */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <getopt.h>
+#include <xtables.h>
+
+#include <linux/netfilter_ipv4/ipt_ttl.h>
+
+static void ttl_help(void)
+{
+	printf(
+"ttl match options:\n"
+"  --ttl-eq value	Match time to live value\n"
+"  --ttl-lt value	Match TTL < value\n"
+"  --ttl-gt value	Match TTL > value\n");
+}
+
+static int ttl_parse(int c, char **argv, int invert, unsigned int *flags,
+                     const void *entry, struct xt_entry_match **match)
+{
+	struct ipt_ttl_info *info = (struct ipt_ttl_info *) (*match)->data;
+	unsigned int value;
+
+	xtables_check_inverse(optarg, &invert, &optind, 0, argv);
+
+	switch (c) {
+		case '2':
+			if (!xtables_strtoui(optarg, NULL, &value, 0, UINT8_MAX))
+				xtables_error(PARAMETER_PROBLEM,
+				           "ttl: Expected value between 0 and 255");
+
+			if (invert)
+				info->mode = IPT_TTL_NE;
+			else
+				info->mode = IPT_TTL_EQ;
+
+			/* is 0 allowed? */
+			info->ttl = value;
+			break;
+		case '3':
+			if (!xtables_strtoui(optarg, NULL, &value, 0, UINT8_MAX))
+				xtables_error(PARAMETER_PROBLEM,
+				           "ttl: Expected value between 0 and 255");
+
+			if (invert) 
+				xtables_error(PARAMETER_PROBLEM,
+						"ttl: unexpected `!'");
+
+			info->mode = IPT_TTL_LT;
+			info->ttl = value;
+			break;
+		case '4':
+			if (!xtables_strtoui(optarg, NULL, &value, 0, UINT8_MAX))
+				xtables_error(PARAMETER_PROBLEM,
+				           "ttl: Expected value between 0 and 255");
+
+			if (invert)
+				xtables_error(PARAMETER_PROBLEM,
+						"ttl: unexpected `!'");
+
+			info->mode = IPT_TTL_GT;
+			info->ttl = value;
+			break;
+		default:
+			return 0;
+
+	}
+
+	if (*flags) 
+		xtables_error(PARAMETER_PROBLEM,
+				"Can't specify TTL option twice");
+	*flags = 1;
+
+	return 1;
+}
+
+static void ttl_check(unsigned int flags)
+{
+	if (!flags) 
+		xtables_error(PARAMETER_PROBLEM,
+			"TTL match: You must specify one of "
+			"`--ttl-eq', `--ttl-lt', `--ttl-gt");
+}
+
+static void ttl_print(const void *ip, const struct xt_entry_match *match,
+                      int numeric)
+{
+	const struct ipt_ttl_info *info = 
+		(struct ipt_ttl_info *) match->data;
+
+	printf("TTL match ");
+	switch (info->mode) {
+		case IPT_TTL_EQ:
+			printf("TTL == ");
+			break;
+		case IPT_TTL_NE:
+			printf("TTL != ");
+			break;
+		case IPT_TTL_LT:
+			printf("TTL < ");
+			break;
+		case IPT_TTL_GT:
+			printf("TTL > ");
+			break;
+	}
+	printf("%u ", info->ttl);
+}
+
+static void ttl_save(const void *ip, const struct xt_entry_match *match)
+{
+	const struct ipt_ttl_info *info =
+		(struct ipt_ttl_info *) match->data;
+
+	switch (info->mode) {
+		case IPT_TTL_EQ:
+			printf("--ttl-eq ");
+			break;
+		case IPT_TTL_NE:
+			printf("! --ttl-eq ");
+			break;
+		case IPT_TTL_LT:
+			printf("--ttl-lt ");
+			break;
+		case IPT_TTL_GT:
+			printf("--ttl-gt ");
+			break;
+		default:
+			/* error */
+			break;
+	}
+	printf("%u ", info->ttl);
+}
+
+static const struct option ttl_opts[] = {
+	{ "ttl", 1, NULL, '2' },
+	{ "ttl-eq", 1, NULL, '2'},
+	{ "ttl-lt", 1, NULL, '3'},
+	{ "ttl-gt", 1, NULL, '4'},
+	{ .name = NULL }
+};
+
+static struct xtables_match ttl_mt_reg = {
+	.name		= "ttl",
+	.version	= XTABLES_VERSION,
+	.family		= NFPROTO_IPV4,
+	.size		= XT_ALIGN(sizeof(struct ipt_ttl_info)),
+	.userspacesize	= XT_ALIGN(sizeof(struct ipt_ttl_info)),
+	.help		= ttl_help,
+	.parse		= ttl_parse,
+	.final_check	= ttl_check,
+	.print		= ttl_print,
+	.save		= ttl_save,
+	.extra_opts	= ttl_opts,
+};
+
+
+void _init(void) 
+{
+	xtables_register_match(&ttl_mt_reg);
+}