1 files changed, 135 insertions, 0 deletions
diff --git a/extensions/libipt_ttl.c b/extensions/libipt_ttl.c
new file mode 100644
index 00000000..6370cb67
--- /dev/null
+++ b/extensions/libipt_ttl.c
@@ -0,0 +1,135 @@
+/* Shared library add-on to iptables to add TTL matching support 
+ * (C) 2000 by Harald Welte <laforge@gnumonks.org>
+ *
+ * This program is released under the terms of GNU GPL */
+#include <stdio.h>
+#include <xtables.h>
+#include <linux/netfilter_ipv4/ipt_ttl.h>
+
+enum {
+	O_TTL_EQ = 0,
+	O_TTL_LT,
+	O_TTL_GT,
+	F_TTL_EQ = 1 << O_TTL_EQ,
+	F_TTL_LT = 1 << O_TTL_LT,
+	F_TTL_GT = 1 << O_TTL_GT,
+	F_ANY    = F_TTL_EQ | F_TTL_LT | F_TTL_GT,
+};
+
+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 void ttl_parse(struct xt_option_call *cb)
+{
+	struct ipt_ttl_info *info = cb->data;
+
+	xtables_option_parse(cb);
+	switch (cb->entry->id) {
+	case O_TTL_EQ:
+		info->mode = cb->invert ? IPT_TTL_NE : IPT_TTL_EQ;
+		break;
+	case O_TTL_LT:
+		info->mode = IPT_TTL_LT;
+		break;
+	case O_TTL_GT:
+		info->mode = IPT_TTL_GT;
+		break;
+	}
+}
+
+static void ttl_check(struct xt_fcheck_call *cb)
+{
+	if (!(cb->xflags & F_ANY))
+		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);
+}
+
+#define s struct ipt_ttl_info
+static const struct xt_option_entry ttl_opts[] = {
+	{.name = "ttl-lt", .id = O_TTL_LT, .excl = F_ANY, .type = XTTYPE_UINT8,
+	 .flags = XTOPT_PUT, XTOPT_POINTER(s, ttl)},
+	{.name = "ttl-gt", .id = O_TTL_GT, .excl = F_ANY, .type = XTTYPE_UINT8,
+	 .flags = XTOPT_PUT, XTOPT_POINTER(s, ttl)},
+	{.name = "ttl-eq", .id = O_TTL_EQ, .excl = F_ANY, .type = XTTYPE_UINT8,
+	 .flags = XTOPT_INVERT | XTOPT_PUT, XTOPT_POINTER(s, ttl)},
+	{.name = "ttl", .id = O_TTL_EQ, .excl = F_ANY, .type = XTTYPE_UINT8,
+	 .flags = XTOPT_PUT, XTOPT_POINTER(s, ttl)},
+	XTOPT_TABLEEND,
+};
+#undef s
+
+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,
+	.print		= ttl_print,
+	.save		= ttl_save,
+	.x6_parse	= ttl_parse,
+	.x6_fcheck	= ttl_check,
+	.x6_options	= ttl_opts,
+};
+
+
+void _init(void) 
+{
+	xtables_register_match(&ttl_mt_reg);
+}