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-rwxr-xr-xextensions/.helper-test2
-rw-r--r--extensions/libipt_helper.c109
2 files changed, 111 insertions, 0 deletions
diff --git a/extensions/.helper-test b/extensions/.helper-test
new file mode 100755
index 00000000..a9a9b726
--- /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 00000000..ddb42eea
--- /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);
+}