Merge commit 'origin/trunk@12184' into fedora

[iptables.git] / trunk / extensions / libxt_TCPMSS.c

diff --git a/trunk/extensions/libxt_TCPMSS.c b/trunk/extensions/libxt_TCPMSS.c
new file mode 100644 (file)
index 0000000..fbf73c9
--- /dev/null
+++ b/trunk/extensions/libxt_TCPMSS.c
@@ -0,0 +1,158 @@
+/* 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 <xtables.h>
+#include <linux/netfilter/x_tables.h>
+#include <linux/netfilter/xt_TCPMSS.h>
+
+struct mssinfo {
+       struct xt_entry_target t;
+       struct xt_tcpmss_info mss;
+};
+
+/* Function which prints out usage message. */
+static void __TCPMSS_help(int hdrsize)
+{
+       printf(
+"TCPMSS target mutually-exclusive options:\n"
+"  --set-mss value               explicitly set MSS option to specified value\n"
+"  --clamp-mss-to-pmtu           automatically clamp MSS value to (path_MTU - %d)\n",
+hdrsize);
+}
+
+static void TCPMSS_help(void)
+{
+       __TCPMSS_help(40);
+}
+
+static void TCPMSS_help6(void)
+{
+       __TCPMSS_help(60);
+}
+
+static const struct option TCPMSS_opts[] = {
+       { "set-mss", 1, NULL, '1' },
+       { "clamp-mss-to-pmtu", 0, NULL, '2' },
+       { .name = NULL }
+};
+
+/* Function which parses command options; returns true if it
+   ate an option */
+static int __TCPMSS_parse(int c, char **argv, int invert, unsigned int *flags,
+                          const void *entry, struct xt_entry_target **target,
+                          int hdrsize)
+{
+       struct xt_tcpmss_info *mssinfo
+               = (struct xt_tcpmss_info *)(*target)->data;
+
+       switch (c) {
+               unsigned int mssval;
+
+       case '1':
+               if (*flags)
+                       exit_error(PARAMETER_PROBLEM,
+                                  "TCPMSS target: Only one option may be specified");
+               if (string_to_number(optarg, 0, 65535 - hdrsize, &mssval) == -1)
+                       exit_error(PARAMETER_PROBLEM, "Bad TCPMSS value `%s'", optarg);
+               
+               mssinfo->mss = mssval;
+               *flags = 1;
+               break;
+
+       case '2':
+               if (*flags)
+                       exit_error(PARAMETER_PROBLEM,
+                                  "TCPMSS target: Only one option may be specified");
+               mssinfo->mss = XT_TCPMSS_CLAMP_PMTU;
+               *flags = 1;
+               break;
+
+       default:
+               return 0;
+       }
+
+       return 1;
+}
+
+static int TCPMSS_parse(int c, char **argv, int invert, unsigned int *flags,
+                        const void *entry, struct xt_entry_target **target)
+{
+       return __TCPMSS_parse(c, argv, invert, flags, entry, target, 40);
+}
+
+static int TCPMSS_parse6(int c, char **argv, int invert, unsigned int *flags,
+                         const void *entry, struct xt_entry_target **target)
+{
+       return __TCPMSS_parse(c, argv, invert, flags, entry, target, 60);
+}
+
+static void TCPMSS_check(unsigned int flags)
+{
+       if (!flags)
+               exit_error(PARAMETER_PROBLEM,
+                          "TCPMSS target: At least one parameter is required");
+}
+
+/* Prints out the targinfo. */
+static void TCPMSS_print(const void *ip, const struct xt_entry_target *target,
+                         int numeric)
+{
+       const struct xt_tcpmss_info *mssinfo =
+               (const struct xt_tcpmss_info *)target->data;
+       if(mssinfo->mss == XT_TCPMSS_CLAMP_PMTU)
+               printf("TCPMSS clamp to PMTU ");
+       else
+               printf("TCPMSS set %u ", mssinfo->mss);
+}
+
+/* Saves the union ipt_targinfo in parsable form to stdout. */
+static void TCPMSS_save(const void *ip, const struct xt_entry_target *target)
+{
+       const struct xt_tcpmss_info *mssinfo =
+               (const struct xt_tcpmss_info *)target->data;
+
+       if(mssinfo->mss == XT_TCPMSS_CLAMP_PMTU)
+               printf("--clamp-mss-to-pmtu ");
+       else
+               printf("--set-mss %u ", mssinfo->mss);
+}
+
+static struct xtables_target tcpmss_target = {
+       .family         = AF_INET,
+       .name           = "TCPMSS",
+       .version        = XTABLES_VERSION,
+       .size           = XT_ALIGN(sizeof(struct xt_tcpmss_info)),
+       .userspacesize  = XT_ALIGN(sizeof(struct xt_tcpmss_info)),
+       .help           = TCPMSS_help,
+       .parse          = TCPMSS_parse,
+       .final_check    = TCPMSS_check,
+       .print          = TCPMSS_print,
+       .save           = TCPMSS_save,
+       .extra_opts     = TCPMSS_opts,
+};
+
+static struct xtables_target tcpmss_target6 = {
+       .family         = AF_INET6,
+       .name           = "TCPMSS",
+       .version        = XTABLES_VERSION,
+       .size           = XT_ALIGN(sizeof(struct xt_tcpmss_info)),
+       .userspacesize  = XT_ALIGN(sizeof(struct xt_tcpmss_info)),
+       .help           = TCPMSS_help6,
+       .parse          = TCPMSS_parse6,
+       .final_check    = TCPMSS_check,
+       .print          = TCPMSS_print,
+       .save           = TCPMSS_save,
+       .extra_opts     = TCPMSS_opts,
+};
+
+void _init(void)
+{
+       xtables_register_target(&tcpmss_target);
+       xtables_register_target(&tcpmss_target6);
+}