add random6 patch (Maciej Soltysiak)

2 files changed, 155 insertions, 0 deletions

diff --git a/extensions/.random-test6 b/extensions/.random-test6
new file mode 100755
index 0000000..25a431f
--- /dev/null
+++ b/extensions/.random-test6
@@ -0,0 +1,3 @@
+#!/bin/sh
+# True if random is applied.
+[ -f $KERNEL_DIR/include/linux/netfilter_ipv6/ip6t_random.h ] && echo random
diff --git a/extensions/libip6t_random.c b/extensions/libip6t_random.c
new file mode 100644
index 0000000..5f151ea
--- /dev/null
+++ b/extensions/libip6t_random.c
@@ -0,0 +1,152 @@
+/* 
+   Shared library add-on to iptables to add match support for random match.
+   
+   This file is distributed under the terms of the GNU General Public
+   License (GPL). Copies of the GPL can be obtained from:
+   ftp://prep.ai.mit.edu/pub/gnu/GPL
+
+   2001-10-14 Fabrice MARIE <fabrice@netfilter.org> : initial development.
+   2003-04-30 Maciej Soltysiak <solt@dns.toxicfilms.tv> : IPv6 port.
+*/
+
+#include <stdio.h>
+#include <netdb.h>
+#include <string.h>
+#include <stdlib.h>
+#include <syslog.h>
+#include <getopt.h>
+#include <ip6tables.h>
+#include <linux/netfilter_ipv6/ip6_tables.h>
+#include <linux/netfilter_ipv6/ip6t_random.h>
+
+/**
+ * The kernel random routing returns numbers between 0 and 255.
+ * To ease the task of the user in choosing the probability
+ * of matching, we want him to be able to use percentages.
+ * Therefore we have to accept numbers in percentage here,
+ * turn them into number between 0 and 255 for the kernel module,
+ * and turn them back to percentages when we print/save
+ * the rule.
+ */
+
+
+/* Function which prints out usage message. */
+static void
+help(void)
+{
+	printf(
+"random v%s options:\n"
+"  [--average]     percent      The probability in percentage of the match\n"
+"                               If ommited, a probability of 50%% percent is set.\n"
+"                               Percentage must be within : 1 <= percent <= 99.\n\n",
+IPTABLES_VERSION);
+}
+
+static struct option opts[] = {
+	{ "average", 1, 0, '1' },
+	{ 0 }
+};
+
+/* Initialize the target. */
+static void
+init(struct ip6t_entry_match *m, unsigned int *nfcache)
+{
+	struct ip6t_rand_info *randinfo = (struct ip6t_rand_info *)(m)->data;
+	*nfcache |= NFC_UNKNOWN;
+
+	/* We assign the average to be 50 which is our default value */
+	/* 50 * 2.55 = 128 */
+	randinfo->average = 128;
+}
+
+#define IP6T_RAND_OPT_AVERAGE	0x01
+
+/* 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 ip6t_entry *entry,
+      unsigned int *nfcache,
+      struct ip6t_entry_match **match)
+{
+	struct ip6t_rand_info *randinfo = (struct ip6t_rand_info *)(*match)->data;
+	unsigned int num;
+
+	switch (c) {
+	case '1':
+		/* check for common mistakes... */
+		if (invert)
+			exit_error(PARAMETER_PROBLEM,
+				   "Can't specify ! --average");
+		if (*flags & IP6T_RAND_OPT_AVERAGE)
+			exit_error(PARAMETER_PROBLEM,
+				   "Can't specify --average twice");
+
+		/* Remember, this function will interpret a leading 0 to be 
+		   Octal, a leading 0x to be hexdecimal... */
+                if (string_to_number(optarg, 1, 99, &num) == -1 || num < 1)
+                        exit_error(PARAMETER_PROBLEM,
+                                   "bad --average `%s', must be between 1 and 99", optarg);
+
+		/* assign the values */
+		randinfo->average = (int)(num * 2.55);
+		*flags |= IP6T_RAND_OPT_AVERAGE;
+		break;
+	default:
+		return 0;
+	}
+	return 1;
+}
+
+/* Final check; nothing. */
+static void final_check(unsigned int flags)
+{
+}
+
+/* Prints out the targinfo. */
+static void
+print(const struct ip6t_ip6 *ip,
+      const struct ip6t_entry_match *match,
+      int numeric)
+{
+	const struct ip6t_rand_info *randinfo
+		= (const struct ip6t_rand_info *)match->data;
+	div_t result = div((randinfo->average*100), 255);
+	if (result.rem > 127)  /* round up... */
+		++result.quot;
+
+	printf(" random %u%% ", result.quot);
+}
+
+/* Saves the union ip6t_targinfo in parsable form to stdout. */
+static void
+save(const struct ip6t_ip6 *ip, const struct ip6t_entry_match *match)
+{
+	const struct ip6t_rand_info *randinfo
+		= (const struct ip6t_rand_info *)match->data;
+	div_t result = div((randinfo->average *100), 255);
+	if (result.rem > 127)  /* round up... */
+		++result.quot;
+
+	printf("--average %u ", result.quot);
+}
+
+struct ip6tables_match rand_match
+= { NULL,
+    "random",
+    IPTABLES_VERSION,
+    IP6T_ALIGN(sizeof(struct ip6t_rand_info)),
+    IP6T_ALIGN(sizeof(struct ip6t_rand_info)),
+    &help,
+    &init,
+    &parse,
+    &final_check,
+    &print,
+    &save,
+    opts
+};
+
+void _init(void)
+{
+	register_match6(&rand_match);
+}