From c40e3331cc035f0d0c595cad5692df16dc1bd025 Mon Sep 17 00:00:00 2001
From: laforge <laforge>
Date: Fri, 11 Jan 2002 18:41:02 +0000
Subject: helper match (Martin Josefsson)

---
 extensions/.helper-test    |   2 +
 extensions/libipt_helper.c | 109 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 111 insertions(+)
 create mode 100755 extensions/.helper-test
 create mode 100644 extensions/libipt_helper.c

(limited to 'extensions')

diff --git a/extensions/.helper-test b/extensions/.helper-test
new file mode 100755
index 0000000..a9a9b72
--- /dev/null
+++ b/extensions/.helper-test
@@ -0,0 +1,2 @@
+#! /bin/sh
+[ -f $KERNEL_DIR/include/linux/netfilter_ipv4/ipt_helper.h ] && echo helper
diff --git a/extensions/libipt_helper.c b/extensions/libipt_helper.c
new file mode 100644
index 0000000..ddb42ee
--- /dev/null
+++ b/extensions/libipt_helper.c
@@ -0,0 +1,109 @@
+/* Shared library add-on to iptables to add related packet matching support. */
+#include <stdio.h>
+#include <netdb.h>
+#include <string.h>
+#include <stdlib.h>
+#include <getopt.h>
+
+#include <iptables.h>
+#include <linux/netfilter_ipv4/ipt_helper.h>
+
+/* Function which prints out usage message. */
+static void
+help(void)
+{
+	printf(
+"helper match v%s options:\n"
+"[!] --helper value         Match helper value\n"
+"\n",
+NETFILTER_VERSION);
+}
+
+static struct option opts[] = {
+	{ "helper", 1, 0, '1' },
+	{0}
+};
+
+/* Initialize the match. */
+static void
+init(struct ipt_entry_match *m, unsigned int *nfcache)
+{
+	/* Can't cache this. */
+	*nfcache |= NFC_UNKNOWN;
+}
+
+/* Function which parses command options; returns true if it
+   ate an option */
+static int
+parse(int c, char **argv, int invert, unsigned int *flags,
+      const struct ipt_entry *entry,
+      unsigned int *nfcache,
+      struct ipt_entry_match **match)
+{
+	struct ipt_helper_info *info = (struct ipt_helper_info *)(*match)->data;
+
+	switch (c) {
+	case '1':
+		if (check_inverse(optarg, &invert))
+			optind++;
+		strncpy(info->name, optarg, 29);
+		if (invert)
+			info->invert = 1;
+		*flags = 1;
+		break;
+
+	default:
+		return 0;
+	}
+	return 1;
+}
+
+/* Final check; must have specified --helper. */
+static void
+final_check(unsigned int flags)
+{
+	if (!flags)
+		exit_error(PARAMETER_PROBLEM,
+			   "helper match: You must specify `--helper'");
+}
+
+/* Prints out the info. */
+static void
+print(const struct ipt_ip *ip,
+      const struct ipt_entry_match *match,
+      int numeric)
+{
+	struct ipt_helper_info *info = (struct ipt_helper_info *)match->data;
+
+	printf("helper match %s\"%s\" ", info->invert ? "! " : "", info->name);
+}
+
+/* Saves the union ipt_info in parsable form to stdout. */
+static void
+save(const struct ipt_ip *ip, const struct ipt_entry_match *match)
+{
+	struct ipt_helper_info *info = (struct ipt_helper_info *)match->data;
+
+	printf("%s--helper \"%s\" ",info->invert ? "! " : "", info->name);
+}
+
+static
+struct iptables_match helper
+= { NULL,
+    "helper",
+    NETFILTER_VERSION,
+    IPT_ALIGN(sizeof(struct ipt_helper_info)),
+    IPT_ALIGN(sizeof(struct ipt_helper_info)),
+    &help,
+    &init,
+    &parse,
+    &final_check,
+    &print,
+    &save,
+    opts
+};
+
+void _init(void)
+{
+	register_match(&helper);
+}
-- 
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