Here is the iptables patch.
commit c23a3f536b11396c2a11df39fe0ae8386d5a12b1
Author: Nicolas Bareil <nico@xxxxxxxxx>
Date: Tue May 27 17:01:00 2008 +0200
scrubbing support
diff --git a/extensions/libip6t_SCRUB.c b/extensions/libip6t_SCRUB.c
new file mode 100644
index 0000000..7d21083
--- /dev/null
+++ b/extensions/libip6t_SCRUB.c
@@ -0,0 +1,218 @@
+/* Shared library add-on to iptables for the SCRUB target
+ * (C) 2008 by Nicolas Bareil <nico@xxxxxxxxx>
+ *
+ * This program is distributed under the terms of GNU GPL
+ */
+#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_ipv6/ip6_tables.h>
+
+#include <linux/netfilter/ipt_scrub.h>
+#include <linux/netfilter/nf_conntrack_common.h>
+
+#define SCRUB_ALL (SCRUB_IP_TOS_ADJUST|SCRUB_IP_RAND_ID_ADJUST|SCRUB_IP_TTL_ADJUST|SCRUB_TCP_SEQ_ADJUST|SCRUB_TCP_OPT_TIMESTAMP_ADJUST|SCRUB_TCP_OPT_MSS_ADJUST)
+
+static void init(struct xt_entry_target *t)
+{
+ struct ipt_scrub_info *info = (struct ipt_scrub_info *) t->data;
+
+ info->flags = 0;
+ info->ttl.scrubbing_default = SCRUB_NORMALIZE_TTL;
+ info->ttl.modifying_threshold = SCRUB_TTL_LOW_THRESHOLD;
+ info->ttl.dropping_threshold = SCRUB_TTL_DROP_IF_LOWER;
+}
+
+static void help(void)
+{
+ printf(
+"SCRUB target v%s options\n"
+" --rand-ipid value Set a random IP ID\n"
+, XTABLES_VERSION);
+}
+
+static int parse(int c, char **argv, int invert, unsigned int *flags,
+ const void *entry,
+ struct xt_entry_target **target)
+{
+ struct ipt_scrub_info *info = (struct ipt_scrub_info *) (*target)->data;
+
+ *flags=1;
+
+ switch (c) {
+ case '!':
+ /* do not overwrite "--no-something" */
+ info->flags= (SCRUB_ALL & ~info->flags) ;
+
+ case 'a':
+ info->flags = (info->flags & ~SCRUB_IP_TOS_ADJUST);
+ break;
+ case '0':
+ info->flags |= SCRUB_IP_TOS_ADJUST;
+ break;
+
+ case 'b':
+ info->flags = (info->flags & ~SCRUB_IP_RAND_ID_ADJUST);
+ break;
+ case '1':
+ info->flags |= SCRUB_IP_RAND_ID_ADJUST;
+ break;
+
+ case 'j':
+ info->flags = (info->flags & ~SCRUB_IP_TTL_ADJUST);
+ break;
+ case '9':
+ info->flags |= SCRUB_IP_TTL_ADJUST;
+ break;
+
+ case '2':
+ if (string_to_number(optarg, 0, 255, (unsigned int *) &(info->ttl.scrubbing_default)) == -1)
+ exit_error(PARAMETER_PROBLEM, "Invalid threshold");
+ break;
+
+ case '3':
+ if (string_to_number(optarg, 0, 255, (unsigned int *) &(info->ttl.modifying_threshold)) == -1)
+ exit_error(PARAMETER_PROBLEM, "Invalid threshold");
+ break;
+
+ case '4':
+ if (string_to_number(optarg, 0, 255, (unsigned int *) &(info->ttl.dropping_threshold)) == -1)
+ exit_error(PARAMETER_PROBLEM, "Invalid threshold");
+ break;
+
+ case 'd':
+ info->flags = (info->flags & ~SCRUB_IP_TTL_ADJUST);
+ break;
+ case '5':
+ info->flags |= SCRUB_IP_TTL_ADJUST;
+ break;
+
+ case 'e':
+ info->flags = (info->flags & ~SCRUB_TCP_SEQ_ADJUST);
+ break;
+ case '6':
+ info->flags |= SCRUB_TCP_SEQ_ADJUST;
+ break;
+
+ case 'f':
+ info->flags = (info->flags & ~SCRUB_TCP_OPT_TIMESTAMP_ADJUST);
+ break;
+ case '7':
+ info->flags |= SCRUB_TCP_OPT_TIMESTAMP_ADJUST;
+ break;
+
+ case 'g':
+ info->flags = (info->flags & ~SCRUB_TCP_OPT_MSS_ADJUST);
+ break;
+ case '8':
+ info->flags |= SCRUB_TCP_OPT_MSS_ADJUST;
+ break;
+
+ default:
+ return 0;
+
+ }
+
+ return 1;
+}
+
+static void final_check(unsigned int flags)
+{
+
+}
+
+static void save(const void *ip, const struct xt_entry_target *target)
+{
+}
+
+static void print(const void *ip,
+ const struct xt_entry_target *target, int numeric)
+{
+ const struct ipt_scrub_info *info =
+ (struct ipt_scrub_info *) target->data;
+
+ printf("SCRUB ");
+
+ if (info->flags == SCRUB_ALL) {
+ printf("everything");
+ return;
+ }
+
+ if (info->flags & SCRUB_TCP_SEQ_ADJUST)
+ printf("random-tcp-isn ");
+
+ if (info->flags & SCRUB_IP_RAND_ID_ADJUST)
+ printf("random-ip-id ");
+
+ if (info->flags & SCRUB_IP_TOS_ADJUST)
+ printf("zeroify-ip-tos ");
+
+ if (info->flags & SCRUB_IP_TTL_ADJUST)
+ printf("default-ttl=%u low-threshold=%u dropping-threschold=%u "
+ , info->ttl.scrubbing_default
+ , info->ttl.modifying_threshold
+ , info->ttl.dropping_threshold);
+
+ if (info->flags & SCRUB_TCP_OPT_MSS_ADJUST)
+ printf("check-tcp-mss ");
+
+ if (info->flags & SCRUB_TCP_OPT_TIMESTAMP_ADJUST)
+ printf("random-tcp-timestamp ");
+
+ if (info->flags & SCRUB_IP_SEALED_TTL_ADJUST)
+ printf("ip-ttl-sealed ");
+}
+
+static struct option opts[] = {
+ { "scrub-everything", 0, 0, '!'},
+ { "ip-zero-tos", 0, 0, '0'},
+ { "ip-rand-id", 0, 0, '1' },
+
+ { "ip-ttl-scrub", 0, 0, '9'},
+ { "ip-ttl-default", 1, 0, '2'},
+ { "ip-ttl-low-threshold", 1, 0, '3'},
+ { "ip-ttl-dropping-threshold", 1, 0, '4'},
+ { "ip-ttl-sealed", 0, 0, '5'},
+
+ { "tcp-rand-seq", 0, 0, '6'},
+ { "tcp-opt-rand-timestamp", 0, 0, '7'},
+ { "tcp-opt-check-mss", 0, 0, '8'},
+
+ /* inverse parameter, is there another way */
+
+ { "no-ip-zero-tos", 0, 0, 'a'},
+ { "no-ip-rand-id", 0, 0, 'b' },
+
+ { "no-ip-ttl-scrub", 0, 0, 'c'},
+ { "no-ip-ttl-sealed", 0, 0, 'd'},
+
+ { "no-tcp-rand-seq", 0, 0, 'e'},
+ { "no-tcp-opt-rand-timestamp", 0, 0, 'f'},
+ { "no-tcp-opt-check-mss", 0, 0, 'g'},
+
+ { 0 }
+};
+
+static struct xtables_target SCRUB = {
+ .next = NULL,
+ .name = "SCRUB",
+ .version = XTABLES_VERSION,
+ .size = XT_ALIGN(sizeof(struct ipt_scrub_info)),
+ .userspacesize = XT_ALIGN(sizeof(struct ipt_scrub_info)),
+ .help = help,
+ .init = init,
+ .parse = parse,
+ .final_check = final_check,
+ .print = print,
+ .save = save,
+ .extra_opts = opts
+};
+
+void _init(void)
+{
+ xtables_register_target(&SCRUB);
+}
diff --git a/extensions/libipt_SCRUB.c b/extensions/libipt_SCRUB.c
new file mode 100644
index 0000000..7d21083
--- /dev/null
+++ b/extensions/libipt_SCRUB.c
@@ -0,0 +1,218 @@
+/* Shared library add-on to iptables for the SCRUB target
+ * (C) 2008 by Nicolas Bareil <nico@xxxxxxxxx>
+ *
+ * This program is distributed under the terms of GNU GPL
+ */
+#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_ipv6/ip6_tables.h>
+
+#include <linux/netfilter/ipt_scrub.h>
+#include <linux/netfilter/nf_conntrack_common.h>
+
+#define SCRUB_ALL (SCRUB_IP_TOS_ADJUST|SCRUB_IP_RAND_ID_ADJUST|SCRUB_IP_TTL_ADJUST|SCRUB_TCP_SEQ_ADJUST|SCRUB_TCP_OPT_TIMESTAMP_ADJUST|SCRUB_TCP_OPT_MSS_ADJUST)
+
+static void init(struct xt_entry_target *t)
+{
+ struct ipt_scrub_info *info = (struct ipt_scrub_info *) t->data;
+
+ info->flags = 0;
+ info->ttl.scrubbing_default = SCRUB_NORMALIZE_TTL;
+ info->ttl.modifying_threshold = SCRUB_TTL_LOW_THRESHOLD;
+ info->ttl.dropping_threshold = SCRUB_TTL_DROP_IF_LOWER;
+}
+
+static void help(void)
+{
+ printf(
+"SCRUB target v%s options\n"
+" --rand-ipid value Set a random IP ID\n"
+, XTABLES_VERSION);
+}
+
+static int parse(int c, char **argv, int invert, unsigned int *flags,
+ const void *entry,
+ struct xt_entry_target **target)
+{
+ struct ipt_scrub_info *info = (struct ipt_scrub_info *) (*target)->data;
+
+ *flags=1;
+
+ switch (c) {
+ case '!':
+ /* do not overwrite "--no-something" */
+ info->flags= (SCRUB_ALL & ~info->flags) ;
+
+ case 'a':
+ info->flags = (info->flags & ~SCRUB_IP_TOS_ADJUST);
+ break;
+ case '0':
+ info->flags |= SCRUB_IP_TOS_ADJUST;
+ break;
+
+ case 'b':
+ info->flags = (info->flags & ~SCRUB_IP_RAND_ID_ADJUST);
+ break;
+ case '1':
+ info->flags |= SCRUB_IP_RAND_ID_ADJUST;
+ break;
+
+ case 'j':
+ info->flags = (info->flags & ~SCRUB_IP_TTL_ADJUST);
+ break;
+ case '9':
+ info->flags |= SCRUB_IP_TTL_ADJUST;
+ break;
+
+ case '2':
+ if (string_to_number(optarg, 0, 255, (unsigned int *) &(info->ttl.scrubbing_default)) == -1)
+ exit_error(PARAMETER_PROBLEM, "Invalid threshold");
+ break;
+
+ case '3':
+ if (string_to_number(optarg, 0, 255, (unsigned int *) &(info->ttl.modifying_threshold)) == -1)
+ exit_error(PARAMETER_PROBLEM, "Invalid threshold");
+ break;
+
+ case '4':
+ if (string_to_number(optarg, 0, 255, (unsigned int *) &(info->ttl.dropping_threshold)) == -1)
+ exit_error(PARAMETER_PROBLEM, "Invalid threshold");
+ break;
+
+ case 'd':
+ info->flags = (info->flags & ~SCRUB_IP_TTL_ADJUST);
+ break;
+ case '5':
+ info->flags |= SCRUB_IP_TTL_ADJUST;
+ break;
+
+ case 'e':
+ info->flags = (info->flags & ~SCRUB_TCP_SEQ_ADJUST);
+ break;
+ case '6':
+ info->flags |= SCRUB_TCP_SEQ_ADJUST;
+ break;
+
+ case 'f':
+ info->flags = (info->flags & ~SCRUB_TCP_OPT_TIMESTAMP_ADJUST);
+ break;
+ case '7':
+ info->flags |= SCRUB_TCP_OPT_TIMESTAMP_ADJUST;
+ break;
+
+ case 'g':
+ info->flags = (info->flags & ~SCRUB_TCP_OPT_MSS_ADJUST);
+ break;
+ case '8':
+ info->flags |= SCRUB_TCP_OPT_MSS_ADJUST;
+ break;
+
+ default:
+ return 0;
+
+ }
+
+ return 1;
+}
+
+static void final_check(unsigned int flags)
+{
+
+}
+
+static void save(const void *ip, const struct xt_entry_target *target)
+{
+}
+
+static void print(const void *ip,
+ const struct xt_entry_target *target, int numeric)
+{
+ const struct ipt_scrub_info *info =
+ (struct ipt_scrub_info *) target->data;
+
+ printf("SCRUB ");
+
+ if (info->flags == SCRUB_ALL) {
+ printf("everything");
+ return;
+ }
+
+ if (info->flags & SCRUB_TCP_SEQ_ADJUST)
+ printf("random-tcp-isn ");
+
+ if (info->flags & SCRUB_IP_RAND_ID_ADJUST)
+ printf("random-ip-id ");
+
+ if (info->flags & SCRUB_IP_TOS_ADJUST)
+ printf("zeroify-ip-tos ");
+
+ if (info->flags & SCRUB_IP_TTL_ADJUST)
+ printf("default-ttl=%u low-threshold=%u dropping-threschold=%u "
+ , info->ttl.scrubbing_default
+ , info->ttl.modifying_threshold
+ , info->ttl.dropping_threshold);
+
+ if (info->flags & SCRUB_TCP_OPT_MSS_ADJUST)
+ printf("check-tcp-mss ");
+
+ if (info->flags & SCRUB_TCP_OPT_TIMESTAMP_ADJUST)
+ printf("random-tcp-timestamp ");
+
+ if (info->flags & SCRUB_IP_SEALED_TTL_ADJUST)
+ printf("ip-ttl-sealed ");
+}
+
+static struct option opts[] = {
+ { "scrub-everything", 0, 0, '!'},
+ { "ip-zero-tos", 0, 0, '0'},
+ { "ip-rand-id", 0, 0, '1' },
+
+ { "ip-ttl-scrub", 0, 0, '9'},
+ { "ip-ttl-default", 1, 0, '2'},
+ { "ip-ttl-low-threshold", 1, 0, '3'},
+ { "ip-ttl-dropping-threshold", 1, 0, '4'},
+ { "ip-ttl-sealed", 0, 0, '5'},
+
+ { "tcp-rand-seq", 0, 0, '6'},
+ { "tcp-opt-rand-timestamp", 0, 0, '7'},
+ { "tcp-opt-check-mss", 0, 0, '8'},
+
+ /* inverse parameter, is there another way */
+
+ { "no-ip-zero-tos", 0, 0, 'a'},
+ { "no-ip-rand-id", 0, 0, 'b' },
+
+ { "no-ip-ttl-scrub", 0, 0, 'c'},
+ { "no-ip-ttl-sealed", 0, 0, 'd'},
+
+ { "no-tcp-rand-seq", 0, 0, 'e'},
+ { "no-tcp-opt-rand-timestamp", 0, 0, 'f'},
+ { "no-tcp-opt-check-mss", 0, 0, 'g'},
+
+ { 0 }
+};
+
+static struct xtables_target SCRUB = {
+ .next = NULL,
+ .name = "SCRUB",
+ .version = XTABLES_VERSION,
+ .size = XT_ALIGN(sizeof(struct ipt_scrub_info)),
+ .userspacesize = XT_ALIGN(sizeof(struct ipt_scrub_info)),
+ .help = help,
+ .init = init,
+ .parse = parse,
+ .final_check = final_check,
+ .print = print,
+ .save = save,
+ .extra_opts = opts
+};
+
+void _init(void)
+{
+ xtables_register_target(&SCRUB);
+}
diff --git a/include/linux/netfilter/nf_conntrack_common.h b/include/linux/netfilter/nf_conntrack_common.h
index 3b452a6..720fabb 100644
--- a/include/linux/netfilter/nf_conntrack_common.h
+++ b/include/linux/netfilter/nf_conntrack_common.h
@@ -132,4 +132,29 @@ enum ip_conntrack_expect_events {
IPEXP_NEW = (1 << IPEXP_NEW_BIT),
};
+enum nf_scrub_transformations {
+ /* scrub tcp sequence adjusting */
+ SCRUB_TCP_SEQ_ADJUST_BIT = 1,
+ SCRUB_TCP_SEQ_ADJUST = (1 << SCRUB_TCP_SEQ_ADJUST_BIT),
+
+ SCRUB_IP_RAND_ID_ADJUST_BIT = 2,
+ SCRUB_IP_RAND_ID_ADJUST = (1 << SCRUB_IP_RAND_ID_ADJUST_BIT),
+
+ SCRUB_IP_TTL_ADJUST_BIT = 3,
+ SCRUB_IP_TTL_ADJUST = (1 << SCRUB_IP_TTL_ADJUST_BIT),
+
+ SCRUB_IP_TOS_ADJUST_BIT = 4,
+ SCRUB_IP_TOS_ADJUST = (1 << SCRUB_IP_TOS_ADJUST_BIT),
+
+ SCRUB_TCP_OPT_MSS_ADJUST_BIT = 5,
+ SCRUB_TCP_OPT_MSS_ADJUST = (1 << SCRUB_TCP_OPT_MSS_ADJUST_BIT),
+
+ SCRUB_TCP_OPT_TIMESTAMP_ADJUST_BIT = 6,
+ SCRUB_TCP_OPT_TIMESTAMP_ADJUST = (1 << SCRUB_TCP_OPT_TIMESTAMP_ADJUST_BIT),
+
+ SCRUB_IP_SEALED_TTL_ADJUST_BIT = 7,
+ SCRUB_IP_SEALED_TTL_ADJUST = (1 << SCRUB_IP_SEALED_TTL_ADJUST_BIT),
+};
+
+
#endif /* _NF_CONNTRACK_COMMON_H */
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