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-rw-r--r--extensions/libipt_REJECT.c159
1 files changed, 159 insertions, 0 deletions
diff --git a/extensions/libipt_REJECT.c b/extensions/libipt_REJECT.c
new file mode 100644
index 00000000..e3365873
--- /dev/null
+++ b/extensions/libipt_REJECT.c
@@ -0,0 +1,159 @@
+/* Shared library add-on to iptables to add customized REJECT support.
+ *
+ * (C) 2000 Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
+ */
+#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_REJECT.h>
+
+struct reject_names {
+ const char *name;
+ const char *alias;
+ enum ipt_reject_with with;
+ const char *desc;
+};
+
+static const struct reject_names reject_table[] = {
+ {"icmp-net-unreachable", "net-unreach",
+ IPT_ICMP_NET_UNREACHABLE, "ICMP network unreachable"},
+ {"icmp-host-unreachable", "host-unreach",
+ IPT_ICMP_HOST_UNREACHABLE, "ICMP host unreachable"},
+ {"icmp-port-unreachable", "port-unreach",
+ IPT_ICMP_PORT_UNREACHABLE, "ICMP port unreachable (default)"},
+ {"icmp-proto-unreachable", "proto-unreach",
+ IPT_ICMP_PROT_UNREACHABLE, "ICMP protocol unreachable"},
+ {"tcp-reset", "rst",
+ IPT_TCP_RESET, "for TCP only: faked TCP RST"},
+ {"echo-reply", "echoreply",
+ IPT_ICMP_ECHOREPLY, "for ICMP echo only: faked ICMP echo reply"},
+};
+
+static void
+print_reject_types()
+{
+ unsigned int i;
+
+ printf("Valid reject types:\n");
+
+ for (i = 0; i < sizeof(reject_table)/sizeof(struct reject_names); i++) {
+ printf(" %-25s\t%s\n", reject_table[i].name, reject_table[i].desc);
+ printf(" %-25s\talias\n", reject_table[i].alias);
+ }
+ printf("\n");
+}
+
+/* Saves the union ipt_targinfo in parsable form to stdout. */
+
+/* Function which prints out usage message. */
+static void
+help(void)
+{
+ printf(
+"REJECT options:\n"
+"--reject-with type drop input packet and send back\n"
+" a reply packet according to type:\n");
+
+ print_reject_types();
+}
+
+static struct option opts[] = {
+ { "reject-with", 1, 0, '1' },
+ { 0 }
+};
+
+/* Allocate and initialize the target. */
+static void
+init(struct ipt_entry_target *t, unsigned int *nfcache)
+{
+ struct ipt_reject_info *reject = (struct ipt_reject_info *)t->data;
+
+ /* default */
+ reject->with = IPT_ICMP_PORT_UNREACHABLE;
+
+ /* 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,
+ struct ipt_entry_target **target)
+{
+ struct ipt_reject_info *reject = (struct ipt_reject_info *)(*target)->data;
+ unsigned int limit = sizeof(reject_table)/sizeof(struct reject_names);
+ unsigned int i;
+
+ switch(c) {
+ case '1':
+ if (check_inverse(optarg, &invert))
+ exit_error(PARAMETER_PROBLEM,
+ "Unexpected `!' after --reject-with");
+ for (i = 0; i < limit; i++) {
+ if ((strncasecmp(reject_table[i].name, optarg, strlen(optarg)) == 0)
+ || (strncasecmp(reject_table[i].alias, optarg, strlen(optarg)) == 0)) {
+ reject->with = reject_table[i].with;
+ return 1;
+ }
+ }
+ exit_error(PARAMETER_PROBLEM, "unknown reject type `%s'",optarg);
+ default:
+ /* Fall through */
+ }
+ return 0;
+}
+
+/* Final check; nothing. */
+static void final_check(unsigned int flags)
+{
+}
+
+/* Prints out ipt_reject_info. */
+static void
+print(const struct ipt_ip *ip,
+ const struct ipt_entry_target *target,
+ int numeric)
+{
+ const struct ipt_reject_info *reject
+ = (const struct ipt_reject_info *)target->data;
+ unsigned int i;
+
+ for (i = 0; i < sizeof(reject_table)/sizeof(struct reject_names); i++) {
+ if (reject_table[i].with == reject->with)
+ break;
+ }
+ printf("reject-with %s ", reject_table[i].name);
+}
+
+/* Saves ipt_reject in parsable form to stdout. */
+static void save(const struct ipt_ip *ip, const struct ipt_entry_target *target)
+{
+ const struct ipt_reject_info *reject
+ = (const struct ipt_reject_info *)target->data;
+
+ printf("--reject-with %s ", reject_table[reject->with].name);
+}
+
+struct iptables_target reject
+= { NULL,
+ "REJECT",
+ NETFILTER_VERSION,
+ sizeof(struct ipt_reject_info),
+ &help,
+ &init,
+ &parse,
+ &final_check,
+ &print,
+ &save,
+ opts
+};
+
+void _init(void)
+{
+ register_target(&reject);
+}