freifunkist-firmware/package/iptables/patches/1.4.0/007-tarpit_support.patch

Index: iptables-1.4.0/extensions/libxt_TARPIT.c
===================================================================
--- /dev/null
+++ iptables-1.4.0/extensions/libxt_TARPIT.c
@@ -0,0 +1,55 @@
+/* Shared library add-on to iptables to add TARPIT target support */
+#include <stdio.h>
+#include <getopt.h>
+
+#include <xtables.h>
+#include <linux/netfilter/x_tables.h>
+
+static void TARPIT_help(void)
+{
+	fputs(
+"TARPIT takes no options\n"
+"\n", stdout);
+}
+
+static struct option TARPIT_opts[] = {
+	{ 0 }
+};
+
+static int TARPIT_parse(int c, char **argv, int invert, unsigned int *flags,
+			const void *entry, struct xt_entry_target **target)
+{
+	return 0;
+}
+
+static void TARPIT_final_check(unsigned int flags)
+{
+}
+
+static void TARPIT_print(const void *ip, const struct xt_entry_target *target,
+			int numeric)
+{
+}
+
+static void TARPIT_save(const void *ip, const struct xt_entry_target *target)
+{
+}
+
+static struct xtables_target tarpit_target = {
+	.family		= AF_INET,
+	.name		= "TARPIT",
+	.version	= IPTABLES_VERSION,
+	.size		= XT_ALIGN(0),
+	.userspacesize	= XT_ALIGN(0),
+	.help		= TARPIT_help,
+	.parse		= TARPIT_parse,
+	.final_check	= TARPIT_final_check,
+	.print		= TARPIT_print,
+	.save		= TARPIT_save,
+	.extra_opts	= TARPIT_opts
+};
+
+void _init(void)
+{
+	xtables_register_target(&tarpit_target);
+}
Index: iptables-1.4.0/extensions/libxt_TARPIT.man
===================================================================
--- /dev/null
+++ iptables-1.4.0/extensions/libxt_TARPIT.man
@@ -0,0 +1,34 @@
+Captures and holds incoming TCP connections using no local
+per-connection resources. Connections are accepted, but immediately
+switched to the persist state (0 byte window), in which the remote
+side stops sending data and asks to continue every 60-240 seconds.
+Attempts to close the connection are ignored, forcing the remote side
+to time out the connection in 12-24 minutes.
+
+This offers similar functionality to LaBrea
+<http://www.hackbusters.net/LaBrea/> but doesn't require dedicated
+hardware or IPs. Any TCP port that you would normally DROP or REJECT
+can instead become a tarpit.
+
+To tarpit connections to TCP port 80 destined for the current machine:
+.IP
+iptables -A INPUT -p tcp -m tcp --dport 80 -j TARPIT
+.P
+To significantly slow down Code Red/Nimda-style scans of unused address
+space, forward unused ip addresses to a Linux box not acting as a router
+(e.g. "ip route 10.0.0.0 255.0.0.0 ip.of.linux.box" on a Cisco), enable IP
+forwarding on the Linux box, and add:
+.IP
+iptables -A FORWARD -p tcp -j TARPIT
+.IP
+iptables -A FORWARD -j DROP
+.TP
+NOTE:
+If you use the conntrack module while you are using TARPIT, you should
+also use the NOTRACK target, or the kernel will unnecessarily allocate
+resources for each TARPITted connection. To TARPIT incoming
+connections to the standard IRC port while using conntrack, you could:
+.IP
+iptables -t raw -A PREROUTING -p tcp --dport 6667 -j NOTRACK
+.IP
+iptables -A INPUT -p tcp --dport 6667 -j TARPIT
Index: iptables-1.4.0/extensions/.TARPIT-testx
===================================================================
--- /dev/null
+++ iptables-1.4.0/extensions/.TARPIT-testx
@@ -0,0 +1,2 @@
+#! /bin/sh
+[ -f "$KERNEL_DIR/net/netfilter/xt_TARPIT.c" ] && echo "TARPIT"