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-rw-r--r--extensions/libipt_TCPMSS.c118
1 files changed, 118 insertions, 0 deletions
diff --git a/extensions/libipt_TCPMSS.c b/extensions/libipt_TCPMSS.c
new file mode 100644
index 00000000..db8757b7
--- /dev/null
+++ b/extensions/libipt_TCPMSS.c
@@ -0,0 +1,118 @@
+/* Shared library add-on to iptables to add TCPMSS target support.
+ *
+ * Copyright (c) 2000 Marc Boucher
+*/
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <getopt.h>
+
+#include <iptables.h>
+#include <linux/netfilter_ipv4/ip_tables.h>
+#include <linux/netfilter_ipv4/ipt_TCPMSS.h>
+
+struct mssinfo {
+ struct ipt_entry_target t;
+ struct ipt_tcpmss_info mss;
+};
+
+/* Function which prints out usage message. */
+static void
+help(void)
+{
+ printf(
+"TCPMSS target v%s options:\n"
+" --set-mss value Value to set MSS option to\n",
+NETFILTER_VERSION);
+}
+
+static struct option opts[] = {
+ { "set-mss", 1, 0, '1' },
+ { 0 }
+};
+
+/* Initialize the target. */
+static void
+init(struct ipt_entry_target *t, unsigned int *nfcache)
+{
+}
+
+/* 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,
+ struct ipt_entry_target **target)
+{
+ struct ipt_tcpmss_info *mssinfo
+ = (struct ipt_tcpmss_info *)(*target)->data;
+
+ switch (c) {
+ int mssval;
+
+ case '1':
+ if (*flags)
+ exit_error(PARAMETER_PROBLEM,
+ "TCPMSS target: Can't specify --set-mss twice");
+ if ((mssval = string_to_number(optarg, 0, 65535)) == -1)
+ exit_error(PARAMETER_PROBLEM, "Bad TCPMSS value `%s'", optarg);
+
+ mssinfo->mss = mssval;
+ *flags = 1;
+ break;
+
+ default:
+ return 0;
+ }
+
+ return 1;
+}
+
+static void
+final_check(unsigned int flags)
+{
+ if (!flags)
+ exit_error(PARAMETER_PROBLEM,
+ "TCPMSS target: Parameter --set-mss is required");
+}
+
+/* Prints out the targinfo. */
+static void
+print(const struct ipt_ip *ip,
+ const struct ipt_entry_target *target,
+ int numeric)
+{
+ const struct ipt_tcpmss_info *mssinfo =
+ (const struct ipt_tcpmss_info *)target->data;
+ printf("TCPMSS set %u ", mssinfo->mss);
+}
+
+/* Saves the union ipt_targinfo in parsable form to stdout. */
+static void
+save(const struct ipt_ip *ip, const struct ipt_entry_target *target)
+{
+ const struct ipt_tcpmss_info *mssinfo =
+ (const struct ipt_tcpmss_info *)target->data;
+
+ printf("--set-mss %u ", mssinfo->mss);
+}
+
+struct iptables_target mss
+= { NULL,
+ "TCPMSS",
+ NETFILTER_VERSION,
+ IPT_ALIGN(sizeof(struct ipt_tcpmss_info)),
+ IPT_ALIGN(sizeof(struct ipt_tcpmss_info)),
+ &help,
+ &init,
+ &parse,
+ &final_check,
+ &print,
+ &save,
+ opts
+};
+
+void _init(void)
+{
+ register_target(&mss);
+}