---

yaml
---
r: 135501
b: refs/heads/master
c: 0269ea4
h: refs/heads/master
i:
  135499: cdcac7d
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 1546000fe8db0d3f47b0ef1dd487ec23fbd95313
+refs/heads/master: 0269ea4937343536ec7e85649932bc8c9686ea78

trunk/include/linux/netfilter/Kbuild

@@ -21,6 +21,7 @@ header-y += xt_connbytes.h
 header-y += xt_connlimit.h
 header-y += xt_connmark.h
 header-y += xt_conntrack.h
+header-y += xt_cluster.h
 header-y += xt_dccp.h
 header-y += xt_dscp.h
 header-y += xt_esp.h

trunk/include/linux/netfilter/xt_cluster.h

@@ -0,0 +1,15 @@
+#ifndef _XT_CLUSTER_MATCH_H
+#define _XT_CLUSTER_MATCH_H
+
+enum xt_cluster_flags {
+	XT_CLUSTER_F_INV	= (1 << 0)
+};
+
+struct xt_cluster_match_info {
+	u_int32_t		total_nodes;
+	u_int32_t		node_mask;
+	u_int32_t		hash_seed;
+	u_int32_t		flags;
+};
+
+#endif /* _XT_CLUSTER_MATCH_H */

trunk/net/netfilter/Kconfig

@@ -527,6 +527,22 @@ config NETFILTER_XT_TARGET_TCPOPTSTRIP
 	  This option adds a "TCPOPTSTRIP" target, which allows you to strip
 	  TCP options from TCP packets.
 
+config NETFILTER_XT_MATCH_CLUSTER
+	tristate '"cluster" match support'
+	depends on NF_CONNTRACK
+	depends on NETFILTER_ADVANCED
+	---help---
+	  This option allows you to build work-load-sharing clusters of
+	  network servers/stateful firewalls without having a dedicated
+	  load-balancing router/server/switch. Basically, this match returns
+	  true when the packet must be handled by this cluster node. Thus,
+	  all nodes see all packets and this match decides which node handles
+	  what packets. The work-load sharing algorithm is based on source
+	  address hashing.
+
+	  If you say Y or M here, try `iptables -m cluster --help` for
+	  more information.
+
 config NETFILTER_XT_MATCH_COMMENT
 	tristate  '"comment" match support'
 	depends on NETFILTER_ADVANCED

trunk/net/netfilter/Makefile

@@ -59,6 +59,7 @@ obj-$(CONFIG_NETFILTER_XT_TARGET_TCPOPTSTRIP) += xt_TCPOPTSTRIP.o
 obj-$(CONFIG_NETFILTER_XT_TARGET_TRACE) += xt_TRACE.o
 
 # matches
+obj-$(CONFIG_NETFILTER_XT_MATCH_CLUSTER) += xt_cluster.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_COMMENT) += xt_comment.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_CONNBYTES) += xt_connbytes.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_CONNLIMIT) += xt_connlimit.o

trunk/net/netfilter/xt_cluster.c

@@ -0,0 +1,164 @@
+/*
+ * (C) 2008-2009 Pablo Neira Ayuso <pablo@netfilter.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/jhash.h>
+#include <linux/ip.h>
+#include <net/ipv6.h>
+
+#include <linux/netfilter/x_tables.h>
+#include <net/netfilter/nf_conntrack.h>
+#include <linux/netfilter/xt_cluster.h>
+
+static inline u_int32_t nf_ct_orig_ipv4_src(const struct nf_conn *ct)
+{
+	return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip;
+}
+
+static inline const void *nf_ct_orig_ipv6_src(const struct nf_conn *ct)
+{
+	return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip6;
+}
+
+static inline u_int32_t
+xt_cluster_hash_ipv4(u_int32_t ip, const struct xt_cluster_match_info *info)
+{
+	return jhash_1word(ip, info->hash_seed);
+}
+
+static inline u_int32_t
+xt_cluster_hash_ipv6(const void *ip, const struct xt_cluster_match_info *info)
+{
+	return jhash2(ip, NF_CT_TUPLE_L3SIZE / sizeof(__u32), info->hash_seed);
+}
+
+static inline u_int32_t
+xt_cluster_hash(const struct nf_conn *ct,
+		const struct xt_cluster_match_info *info)
+{
+	u_int32_t hash = 0;
+
+	switch(nf_ct_l3num(ct)) {
+	case AF_INET:
+		hash = xt_cluster_hash_ipv4(nf_ct_orig_ipv4_src(ct), info);
+		break;
+	case AF_INET6:
+		hash = xt_cluster_hash_ipv6(nf_ct_orig_ipv6_src(ct), info);
+		break;
+	default:
+		WARN_ON(1);
+		break;
+	}
+	return (((u64)hash * info->total_nodes) >> 32);
+}
+
+static inline bool
+xt_cluster_is_multicast_addr(const struct sk_buff *skb, u_int8_t family)
+{
+	bool is_multicast = false;
+
+	switch(family) {
+	case NFPROTO_IPV4:
+		is_multicast = ipv4_is_multicast(ip_hdr(skb)->daddr);
+		break;
+	case NFPROTO_IPV6:
+		is_multicast = ipv6_addr_type(&ipv6_hdr(skb)->daddr) &
+						IPV6_ADDR_MULTICAST;
+		break;
+	default:
+		WARN_ON(1);
+		break;
+	}
+	return is_multicast;
+}
+
+static bool
+xt_cluster_mt(const struct sk_buff *skb, const struct xt_match_param *par)
+{
+	struct sk_buff *pskb = (struct sk_buff *)skb;
+	const struct xt_cluster_match_info *info = par->matchinfo;
+	const struct nf_conn *ct;
+	enum ip_conntrack_info ctinfo;
+	unsigned long hash;
+
+	/* This match assumes that all nodes see the same packets. This can be
+	 * achieved if the switch that connects the cluster nodes support some
+	 * sort of 'port mirroring'. However, if your switch does not support
+	 * this, your cluster nodes can reply ARP request using a multicast MAC
+	 * address. Thus, your switch will flood the same packets to the
+	 * cluster nodes with the same multicast MAC address. Using a multicast
+	 * link address is a RFC 1812 (section 3.3.2) violation, but this works
+	 * fine in practise.
+	 *
+	 * Unfortunately, if you use the multicast MAC address, the link layer
+	 * sets skbuff's pkt_type to PACKET_MULTICAST, which is not accepted
+	 * by TCP and others for packets coming to this node. For that reason,
+	 * this match mangles skbuff's pkt_type if it detects a packet
+	 * addressed to a unicast address but using PACKET_MULTICAST. Yes, I
+	 * know, matches should not alter packets, but we are doing this here
+	 * because we would need to add a PKTTYPE target for this sole purpose.
+	 */
+	if (!xt_cluster_is_multicast_addr(skb, par->family) &&
+	    skb->pkt_type == PACKET_MULTICAST) {
+	    	pskb->pkt_type = PACKET_HOST;
+	}
+
+	ct = nf_ct_get(skb, &ctinfo);
+	if (ct == NULL)
+		return false;
+
+	if (ct == &nf_conntrack_untracked)
+		return false;
+
+	if (ct->master)
+		hash = xt_cluster_hash(ct->master, info);
+	else
+		hash = xt_cluster_hash(ct, info);
+
+	return !!((1 << hash) & info->node_mask) ^
+	       !!(info->flags & XT_CLUSTER_F_INV);
+}
+
+static bool xt_cluster_mt_checkentry(const struct xt_mtchk_param *par)
+{
+	struct xt_cluster_match_info *info = par->matchinfo;
+
+	if (info->node_mask >= (1 << info->total_nodes)) {
+		printk(KERN_ERR "xt_cluster: this node mask cannot be "
+				"higher than the total number of nodes\n");
+		return false;
+	}
+	return true;
+}
+
+static struct xt_match xt_cluster_match __read_mostly = {
+	.name		= "cluster",
+	.family		= NFPROTO_UNSPEC,
+	.match		= xt_cluster_mt,
+	.checkentry	= xt_cluster_mt_checkentry,
+	.matchsize	= sizeof(struct xt_cluster_match_info),
+	.me		= THIS_MODULE,
+};
+
+static int __init xt_cluster_mt_init(void)
+{
+	return xt_register_match(&xt_cluster_match);
+}
+
+static void __exit xt_cluster_mt_fini(void)
+{
+	xt_unregister_match(&xt_cluster_match);
+}
+
+MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Xtables: hash-based cluster match");
+MODULE_ALIAS("ipt_cluster");
+MODULE_ALIAS("ip6t_cluster");
+module_init(xt_cluster_mt_init);
+module_exit(xt_cluster_mt_fini);