Commit 9db5d918 authored by Florian Westphal's avatar Florian Westphal
Browse files

netfilter: ip_tables: remove clusterip target 



Marked as 'to be removed soon' since kernel 4.1 (2015).
Functionality was superseded by the 'cluster' match, added in kernel
2.6.30 (2009).

clusterip_tg_check still has races that can give

 proc_dir_entry 'ipt_CLUSTERIP/10.1.1.2' already registered

followed by a WARN splat.

Remove it instead of trying to fix this up again.
clusterip uapi header is left as-is for now.

Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
parent 2a2fa2ef

net/ipv4/netfilter/Kconfig

+0 −14
Original line number Diff line number Diff line
@@ -259,20 +259,6 @@ config IP_NF_MANGLE 


	  To compile it as a module, choose M here.  If unsure, say N.



config IP_NF_TARGET_CLUSTERIP

	tristate "CLUSTERIP target support"

	depends on IP_NF_MANGLE

	depends on NF_CONNTRACK

	depends on NETFILTER_ADVANCED

	select NF_CONNTRACK_MARK

	select NETFILTER_FAMILY_ARP

	help

	  The CLUSTERIP target allows you to build load-balancing clusters of

	  network servers without having a dedicated load-balancing

	  router/server/switch.



	  To compile it as a module, choose M here.  If unsure, say N.



config IP_NF_TARGET_ECN

	tristate "ECN target support"

	depends on IP_NF_MANGLE

net/ipv4/netfilter/Makefile

+0 −1
Original line number Diff line number Diff line
@@ -39,7 +39,6 @@ obj-$(CONFIG_IP_NF_MATCH_AH) += ipt_ah.o 
obj-$(CONFIG_IP_NF_MATCH_RPFILTER) += ipt_rpfilter.o



# targets

obj-$(CONFIG_IP_NF_TARGET_CLUSTERIP) += ipt_CLUSTERIP.o

obj-$(CONFIG_IP_NF_TARGET_ECN) += ipt_ECN.o

obj-$(CONFIG_IP_NF_TARGET_REJECT) += ipt_REJECT.o

obj-$(CONFIG_IP_NF_TARGET_SYNPROXY) += ipt_SYNPROXY.o

net/ipv4/netfilter/ipt_CLUSTERIP.c

deleted100644 → 0
+0 −929
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/* Cluster IP hashmark target

 * (C) 2003-2004 by Harald Welte <laforge@netfilter.org>

 * based on ideas of Fabio Olive Leite <olive@unixforge.org>

 *

 * Development of this code funded by SuSE Linux AG, https://www.suse.com/

 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>

#include <linux/proc_fs.h>

#include <linux/jhash.h>

#include <linux/bitops.h>

#include <linux/skbuff.h>

#include <linux/slab.h>

#include <linux/ip.h>

#include <linux/tcp.h>

#include <linux/udp.h>

#include <linux/icmp.h>

#include <linux/if_arp.h>

#include <linux/seq_file.h>

#include <linux/refcount.h>

#include <linux/netfilter_arp.h>

#include <linux/netfilter/x_tables.h>

#include <linux/netfilter_ipv4/ip_tables.h>

#include <linux/netfilter_ipv4/ipt_CLUSTERIP.h>

#include <net/netfilter/nf_conntrack.h>

#include <net/net_namespace.h>

#include <net/netns/generic.h>

#include <net/checksum.h>

#include <net/ip.h>



#define CLUSTERIP_VERSION "0.8"



MODULE_LICENSE("GPL");

MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");

MODULE_DESCRIPTION("Xtables: CLUSTERIP target");



struct clusterip_config {

	struct list_head list;			/* list of all configs */

	refcount_t refcount;			/* reference count */

	refcount_t entries;			/* number of entries/rules

						 * referencing us */



	__be32 clusterip;			/* the IP address */

	u_int8_t clustermac[ETH_ALEN];		/* the MAC address */

	int ifindex;				/* device ifindex */

	u_int16_t num_total_nodes;		/* total number of nodes */

	unsigned long local_nodes;		/* node number array */



#ifdef CONFIG_PROC_FS

	struct proc_dir_entry *pde;		/* proc dir entry */

#endif

	enum clusterip_hashmode hash_mode;	/* which hashing mode */

	u_int32_t hash_initval;			/* hash initialization */

	struct rcu_head rcu;			/* for call_rcu */

	struct net *net;			/* netns for pernet list */

	char ifname[IFNAMSIZ];			/* device ifname */

};



#ifdef CONFIG_PROC_FS

static const struct proc_ops clusterip_proc_ops;

#endif



struct clusterip_net {

	struct list_head configs;

	/* lock protects the configs list */

	spinlock_t lock;



	bool clusterip_deprecated_warning;

#ifdef CONFIG_PROC_FS

	struct proc_dir_entry *procdir;

	/* mutex protects the config->pde*/

	struct mutex mutex;

#endif

	unsigned int hook_users;

};



static unsigned int clusterip_arp_mangle(void *priv, struct sk_buff *skb, const struct nf_hook_state *state);



static const struct nf_hook_ops cip_arp_ops = {

	.hook = clusterip_arp_mangle,

	.pf = NFPROTO_ARP,

	.hooknum = NF_ARP_OUT,

	.priority = -1

};



static unsigned int clusterip_net_id __read_mostly;

static inline struct clusterip_net *clusterip_pernet(struct net *net)

{

	return net_generic(net, clusterip_net_id);

}



static inline void

clusterip_config_get(struct clusterip_config *c)

{

	refcount_inc(&c->refcount);

}



static void clusterip_config_rcu_free(struct rcu_head *head)

{

	struct clusterip_config *config;

	struct net_device *dev;



	config = container_of(head, struct clusterip_config, rcu);

	dev = dev_get_by_name(config->net, config->ifname);

	if (dev) {

		dev_mc_del(dev, config->clustermac);

		dev_put(dev);

	}

	kfree(config);

}



static inline void

clusterip_config_put(struct clusterip_config *c)

{

	if (refcount_dec_and_test(&c->refcount))

		call_rcu(&c->rcu, clusterip_config_rcu_free);

}



/* decrease the count of entries using/referencing this config.  If last

 * entry(rule) is removed, remove the config from lists, but don't free it

 * yet, since proc-files could still be holding references */

static inline void

clusterip_config_entry_put(struct clusterip_config *c)

{

	struct clusterip_net *cn = clusterip_pernet(c->net);



	local_bh_disable();

	if (refcount_dec_and_lock(&c->entries, &cn->lock)) {

		list_del_rcu(&c->list);

		spin_unlock(&cn->lock);

		local_bh_enable();

		/* In case anyone still accesses the file, the open/close

		 * functions are also incrementing the refcount on their own,

		 * so it's safe to remove the entry even if it's in use. */

#ifdef CONFIG_PROC_FS

		mutex_lock(&cn->mutex);

		if (cn->procdir)

			proc_remove(c->pde);

		mutex_unlock(&cn->mutex);

#endif

		return;

	}

	local_bh_enable();

}



static struct clusterip_config *

__clusterip_config_find(struct net *net, __be32 clusterip)

{

	struct clusterip_config *c;

	struct clusterip_net *cn = clusterip_pernet(net);



	list_for_each_entry_rcu(c, &cn->configs, list) {

		if (c->clusterip == clusterip)

			return c;

	}



	return NULL;

}



static inline struct clusterip_config *

clusterip_config_find_get(struct net *net, __be32 clusterip, int entry)

{

	struct clusterip_config *c;



	rcu_read_lock_bh();

	c = __clusterip_config_find(net, clusterip);

	if (c) {

#ifdef CONFIG_PROC_FS

		if (!c->pde)

			c = NULL;

		else

#endif

		if (unlikely(!refcount_inc_not_zero(&c->refcount)))

			c = NULL;

		else if (entry) {

			if (unlikely(!refcount_inc_not_zero(&c->entries))) {

				clusterip_config_put(c);

				c = NULL;

			}

		}

	}

	rcu_read_unlock_bh();



	return c;

}



static void

clusterip_config_init_nodelist(struct clusterip_config *c,

			       const struct ipt_clusterip_tgt_info *i)

{

	int n;



	for (n = 0; n < i->num_local_nodes; n++)

		set_bit(i->local_nodes[n] - 1, &c->local_nodes);

}



static int

clusterip_netdev_event(struct notifier_block *this, unsigned long event,

		       void *ptr)

{

	struct net_device *dev = netdev_notifier_info_to_dev(ptr);

	struct net *net = dev_net(dev);

	struct clusterip_net *cn = clusterip_pernet(net);

	struct clusterip_config *c;



	spin_lock_bh(&cn->lock);

	list_for_each_entry_rcu(c, &cn->configs, list) {

		switch (event) {

		case NETDEV_REGISTER:

			if (!strcmp(dev->name, c->ifname)) {

				c->ifindex = dev->ifindex;

				dev_mc_add(dev, c->clustermac);

			}

			break;

		case NETDEV_UNREGISTER:

			if (dev->ifindex == c->ifindex) {

				dev_mc_del(dev, c->clustermac);

				c->ifindex = -1;

			}

			break;

		case NETDEV_CHANGENAME:

			if (!strcmp(dev->name, c->ifname)) {

				c->ifindex = dev->ifindex;

				dev_mc_add(dev, c->clustermac);

			} else if (dev->ifindex == c->ifindex) {

				dev_mc_del(dev, c->clustermac);

				c->ifindex = -1;

			}

			break;

		}

	}

	spin_unlock_bh(&cn->lock);



	return NOTIFY_DONE;

}



static struct clusterip_config *

clusterip_config_init(struct net *net, const struct ipt_clusterip_tgt_info *i,

		      __be32 ip, const char *iniface)

{

	struct clusterip_net *cn = clusterip_pernet(net);

	struct clusterip_config *c;

	struct net_device *dev;

	int err;



	if (iniface[0] == '\0') {

		pr_info("Please specify an interface name\n");

		return ERR_PTR(-EINVAL);

	}



	c = kzalloc(sizeof(*c), GFP_ATOMIC);

	if (!c)

		return ERR_PTR(-ENOMEM);



	dev = dev_get_by_name(net, iniface);

	if (!dev) {

		pr_info("no such interface %s\n", iniface);

		kfree(c);

		return ERR_PTR(-ENOENT);

	}

	c->ifindex = dev->ifindex;

	strcpy(c->ifname, dev->name);

	memcpy(&c->clustermac, &i->clustermac, ETH_ALEN);

	dev_mc_add(dev, c->clustermac);

	dev_put(dev);



	c->clusterip = ip;

	c->num_total_nodes = i->num_total_nodes;

	clusterip_config_init_nodelist(c, i);

	c->hash_mode = i->hash_mode;

	c->hash_initval = i->hash_initval;

	c->net = net;

	refcount_set(&c->refcount, 1);



	spin_lock_bh(&cn->lock);

	if (__clusterip_config_find(net, ip)) {

		err = -EBUSY;

		goto out_config_put;

	}



	list_add_rcu(&c->list, &cn->configs);

	spin_unlock_bh(&cn->lock);



#ifdef CONFIG_PROC_FS

	{

		char buffer[16];



		/* create proc dir entry */

		sprintf(buffer, "%pI4", &ip);

		mutex_lock(&cn->mutex);

		c->pde = proc_create_data(buffer, 0600,

					  cn->procdir,

					  &clusterip_proc_ops, c);

		mutex_unlock(&cn->mutex);

		if (!c->pde) {

			err = -ENOMEM;

			goto err;

		}

	}

#endif



	refcount_set(&c->entries, 1);

	return c;



#ifdef CONFIG_PROC_FS

err:

#endif

	spin_lock_bh(&cn->lock);

	list_del_rcu(&c->list);

out_config_put:

	spin_unlock_bh(&cn->lock);

	clusterip_config_put(c);

	return ERR_PTR(err);

}



#ifdef CONFIG_PROC_FS

static int

clusterip_add_node(struct clusterip_config *c, u_int16_t nodenum)

{



	if (nodenum == 0 ||

	    nodenum > c->num_total_nodes)

		return 1;



	/* check if we already have this number in our bitfield */

	if (test_and_set_bit(nodenum - 1, &c->local_nodes))

		return 1;



	return 0;

}



static bool

clusterip_del_node(struct clusterip_config *c, u_int16_t nodenum)

{

	if (nodenum == 0 ||

	    nodenum > c->num_total_nodes)

		return true;



	if (test_and_clear_bit(nodenum - 1, &c->local_nodes))

		return false;



	return true;

}

#endif



static inline u_int32_t

clusterip_hashfn(const struct sk_buff *skb,

		 const struct clusterip_config *config)

{

	const struct iphdr *iph = ip_hdr(skb);

	unsigned long hashval;

	u_int16_t sport = 0, dport = 0;

	int poff;



	poff = proto_ports_offset(iph->protocol);

	if (poff >= 0) {

		const u_int16_t *ports;

		u16 _ports[2];



		ports = skb_header_pointer(skb, iph->ihl * 4 + poff, 4, _ports);

		if (ports) {

			sport = ports[0];

			dport = ports[1];

		}

	} else {

		net_info_ratelimited("unknown protocol %u\n", iph->protocol);

	}



	switch (config->hash_mode) {

	case CLUSTERIP_HASHMODE_SIP:

		hashval = jhash_1word(ntohl(iph->saddr),

				      config->hash_initval);

		break;

	case CLUSTERIP_HASHMODE_SIP_SPT:

		hashval = jhash_2words(ntohl(iph->saddr), sport,

				       config->hash_initval);

		break;

	case CLUSTERIP_HASHMODE_SIP_SPT_DPT:

		hashval = jhash_3words(ntohl(iph->saddr), sport, dport,

				       config->hash_initval);

		break;

	default:

		/* to make gcc happy */

		hashval = 0;

		/* This cannot happen, unless the check function wasn't called

		 * at rule load time */

		pr_info("unknown mode %u\n", config->hash_mode);

		BUG();

		break;

	}



	/* node numbers are 1..n, not 0..n */

	return reciprocal_scale(hashval, config->num_total_nodes) + 1;

}



static inline int

clusterip_responsible(const struct clusterip_config *config, u_int32_t hash)

{

	return test_bit(hash - 1, &config->local_nodes);

}



/***********************************************************************

 * IPTABLES TARGET

 ***********************************************************************/



static unsigned int

clusterip_tg(struct sk_buff *skb, const struct xt_action_param *par)

{

	const struct ipt_clusterip_tgt_info *cipinfo = par->targinfo;

	struct nf_conn *ct;

	enum ip_conntrack_info ctinfo;

	u_int32_t hash;



	/* don't need to clusterip_config_get() here, since refcount

	 * is only decremented by destroy() - and ip_tables guarantees

	 * that the ->target() function isn't called after ->destroy() */



	ct = nf_ct_get(skb, &ctinfo);

	if (ct == NULL)

		return NF_DROP;



	/* special case: ICMP error handling. conntrack distinguishes between

	 * error messages (RELATED) and information requests (see below) */

	if (ip_hdr(skb)->protocol == IPPROTO_ICMP &&

	    (ctinfo == IP_CT_RELATED ||

	     ctinfo == IP_CT_RELATED_REPLY))

		return XT_CONTINUE;



	/* nf_conntrack_proto_icmp guarantees us that we only have ICMP_ECHO,

	 * TIMESTAMP, INFO_REQUEST or ICMP_ADDRESS type icmp packets from here

	 * on, which all have an ID field [relevant for hashing]. */



	hash = clusterip_hashfn(skb, cipinfo->config);



	switch (ctinfo) {

	case IP_CT_NEW:

		WRITE_ONCE(ct->mark, hash);

		break;

	case IP_CT_RELATED:

	case IP_CT_RELATED_REPLY:

		/* FIXME: we don't handle expectations at the moment.

		 * They can arrive on a different node than

		 * the master connection (e.g. FTP passive mode) */

	case IP_CT_ESTABLISHED:

	case IP_CT_ESTABLISHED_REPLY:

		break;

	default:			/* Prevent gcc warnings */

		break;

	}



#ifdef DEBUG

	nf_ct_dump_tuple_ip(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);

#endif

	pr_debug("hash=%u ct_hash=%u ", hash, READ_ONCE(ct->mark));

	if (!clusterip_responsible(cipinfo->config, hash)) {

		pr_debug("not responsible\n");

		return NF_DROP;

	}

	pr_debug("responsible\n");



	/* despite being received via linklayer multicast, this is

	 * actually a unicast IP packet. TCP doesn't like PACKET_MULTICAST */

	skb->pkt_type = PACKET_HOST;



	return XT_CONTINUE;

}



static int clusterip_tg_check(const struct xt_tgchk_param *par)

{

	struct ipt_clusterip_tgt_info *cipinfo = par->targinfo;

	struct clusterip_net *cn = clusterip_pernet(par->net);

	const struct ipt_entry *e = par->entryinfo;

	struct clusterip_config *config;

	int ret, i;



	if (par->nft_compat) {

		pr_err("cannot use CLUSTERIP target from nftables compat\n");

		return -EOPNOTSUPP;

	}



	if (cn->hook_users == UINT_MAX)

		return -EOVERFLOW;



	if (cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP &&

	    cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP_SPT &&

	    cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP_SPT_DPT) {

		pr_info("unknown mode %u\n", cipinfo->hash_mode);

		return -EINVAL;



	}

	if (e->ip.dmsk.s_addr != htonl(0xffffffff) ||

	    e->ip.dst.s_addr == 0) {

		pr_info("Please specify destination IP\n");

		return -EINVAL;

	}

	if (cipinfo->num_local_nodes > ARRAY_SIZE(cipinfo->local_nodes)) {

		pr_info("bad num_local_nodes %u\n", cipinfo->num_local_nodes);

		return -EINVAL;

	}

	for (i = 0; i < cipinfo->num_local_nodes; i++) {

		if (cipinfo->local_nodes[i] - 1 >=

		    sizeof(config->local_nodes) * 8) {

			pr_info("bad local_nodes[%d] %u\n",

				i, cipinfo->local_nodes[i]);

			return -EINVAL;

		}

	}



	config = clusterip_config_find_get(par->net, e->ip.dst.s_addr, 1);

	if (!config) {

		if (!(cipinfo->flags & CLUSTERIP_FLAG_NEW)) {

			pr_info("no config found for %pI4, need 'new'\n",

				&e->ip.dst.s_addr);

			return -EINVAL;

		} else {

			config = clusterip_config_init(par->net, cipinfo,

						       e->ip.dst.s_addr,

						       e->ip.iniface);

			if (IS_ERR(config))

				return PTR_ERR(config);

		}

	} else if (memcmp(&config->clustermac, &cipinfo->clustermac, ETH_ALEN)) {

		clusterip_config_entry_put(config);

		clusterip_config_put(config);

		return -EINVAL;

	}



	ret = nf_ct_netns_get(par->net, par->family);

	if (ret < 0) {

		pr_info("cannot load conntrack support for proto=%u\n",

			par->family);

		clusterip_config_entry_put(config);

		clusterip_config_put(config);

		return ret;

	}



	if (cn->hook_users == 0) {

		ret = nf_register_net_hook(par->net, &cip_arp_ops);



		if (ret < 0) {

			clusterip_config_entry_put(config);

			clusterip_config_put(config);

			nf_ct_netns_put(par->net, par->family);

			return ret;

		}

	}



	cn->hook_users++;



	if (!cn->clusterip_deprecated_warning) {

		pr_info("ipt_CLUSTERIP is deprecated and it will removed soon, "

			"use xt_cluster instead\n");

		cn->clusterip_deprecated_warning = true;

	}



	cipinfo->config = config;

	return ret;

}



/* drop reference count of cluster config when rule is deleted */

static void clusterip_tg_destroy(const struct xt_tgdtor_param *par)

{

	const struct ipt_clusterip_tgt_info *cipinfo = par->targinfo;

	struct clusterip_net *cn = clusterip_pernet(par->net);



	/* if no more entries are referencing the config, remove it

	 * from the list and destroy the proc entry */

	clusterip_config_entry_put(cipinfo->config);



	clusterip_config_put(cipinfo->config);



	nf_ct_netns_put(par->net, par->family);

	cn->hook_users--;



	if (cn->hook_users == 0)

		nf_unregister_net_hook(par->net, &cip_arp_ops);

}



#ifdef CONFIG_NETFILTER_XTABLES_COMPAT

struct compat_ipt_clusterip_tgt_info

{

	u_int32_t	flags;

	u_int8_t	clustermac[6];

	u_int16_t	num_total_nodes;

	u_int16_t	num_local_nodes;

	u_int16_t	local_nodes[CLUSTERIP_MAX_NODES];

	u_int32_t	hash_mode;

	u_int32_t	hash_initval;

	compat_uptr_t	config;

};

#endif /* CONFIG_NETFILTER_XTABLES_COMPAT */



static struct xt_target clusterip_tg_reg __read_mostly = {

	.name		= "CLUSTERIP",

	.family		= NFPROTO_IPV4,

	.target		= clusterip_tg,

	.checkentry	= clusterip_tg_check,

	.destroy	= clusterip_tg_destroy,

	.targetsize	= sizeof(struct ipt_clusterip_tgt_info),

	.usersize	= offsetof(struct ipt_clusterip_tgt_info, config),

#ifdef CONFIG_NETFILTER_XTABLES_COMPAT

	.compatsize	= sizeof(struct compat_ipt_clusterip_tgt_info),

#endif /* CONFIG_NETFILTER_XTABLES_COMPAT */

	.me		= THIS_MODULE

};





/***********************************************************************

 * ARP MANGLING CODE

 ***********************************************************************/



/* hardcoded for 48bit ethernet and 32bit ipv4 addresses */

struct arp_payload {

	u_int8_t src_hw[ETH_ALEN];

	__be32 src_ip;

	u_int8_t dst_hw[ETH_ALEN];

	__be32 dst_ip;

} __packed;



#ifdef DEBUG

static void arp_print(struct arp_payload *payload)

{

#define HBUFFERLEN 30

	char hbuffer[HBUFFERLEN];

	int j, k;



	for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < ETH_ALEN; j++) {

		hbuffer[k++] = hex_asc_hi(payload->src_hw[j]);

		hbuffer[k++] = hex_asc_lo(payload->src_hw[j]);

		hbuffer[k++] = ':';

	}

	hbuffer[--k] = '\0';



	pr_debug("src %pI4@%s, dst %pI4\n",

		 &payload->src_ip, hbuffer, &payload->dst_ip);

}

#endif



static unsigned int

clusterip_arp_mangle(void *priv, struct sk_buff *skb,

		     const struct nf_hook_state *state)

{

	struct arphdr *arp = arp_hdr(skb);

	struct arp_payload *payload;

	struct clusterip_config *c;

	struct net *net = state->net;



	/* we don't care about non-ethernet and non-ipv4 ARP */

	if (arp->ar_hrd != htons(ARPHRD_ETHER) ||

	    arp->ar_pro != htons(ETH_P_IP) ||

	    arp->ar_pln != 4 || arp->ar_hln != ETH_ALEN)

		return NF_ACCEPT;



	/* we only want to mangle arp requests and replies */

	if (arp->ar_op != htons(ARPOP_REPLY) &&

	    arp->ar_op != htons(ARPOP_REQUEST))

		return NF_ACCEPT;



	payload = (void *)(arp+1);



	/* if there is no clusterip configuration for the arp reply's

	 * source ip, we don't want to mangle it */

	c = clusterip_config_find_get(net, payload->src_ip, 0);

	if (!c)

		return NF_ACCEPT;



	/* normally the linux kernel always replies to arp queries of

	 * addresses on different interfacs.  However, in the CLUSTERIP case

	 * this wouldn't work, since we didn't subscribe the mcast group on

	 * other interfaces */

	if (c->ifindex != state->out->ifindex) {

		pr_debug("not mangling arp reply on different interface: cip'%d'-skb'%d'\n",

			 c->ifindex, state->out->ifindex);

		clusterip_config_put(c);

		return NF_ACCEPT;

	}



	/* mangle reply hardware address */

	memcpy(payload->src_hw, c->clustermac, arp->ar_hln);



#ifdef DEBUG

	pr_debug("mangled arp reply: ");

	arp_print(payload);

#endif



	clusterip_config_put(c);



	return NF_ACCEPT;

}



/***********************************************************************

 * PROC DIR HANDLING

 ***********************************************************************/



#ifdef CONFIG_PROC_FS



struct clusterip_seq_position {

	unsigned int pos;	/* position */

	unsigned int weight;	/* number of bits set == size */

	unsigned int bit;	/* current bit */

	unsigned long val;	/* current value */

};



static void *clusterip_seq_start(struct seq_file *s, loff_t *pos)

{

	struct clusterip_config *c = s->private;

	unsigned int weight;

	u_int32_t local_nodes;

	struct clusterip_seq_position *idx;



	/* FIXME: possible race */

	local_nodes = c->local_nodes;

	weight = hweight32(local_nodes);

	if (*pos >= weight)

		return NULL;



	idx = kmalloc(sizeof(struct clusterip_seq_position), GFP_KERNEL);

	if (!idx)

		return ERR_PTR(-ENOMEM);



	idx->pos = *pos;

	idx->weight = weight;

	idx->bit = ffs(local_nodes);

	idx->val = local_nodes;

	clear_bit(idx->bit - 1, &idx->val);



	return idx;

}



static void *clusterip_seq_next(struct seq_file *s, void *v, loff_t *pos)

{

	struct clusterip_seq_position *idx = v;



	*pos = ++idx->pos;

	if (*pos >= idx->weight) {

		kfree(v);

		return NULL;

	}

	idx->bit = ffs(idx->val);

	clear_bit(idx->bit - 1, &idx->val);

	return idx;

}



static void clusterip_seq_stop(struct seq_file *s, void *v)

{

	if (!IS_ERR(v))

		kfree(v);

}



static int clusterip_seq_show(struct seq_file *s, void *v)

{

	struct clusterip_seq_position *idx = v;



	if (idx->pos != 0)

		seq_putc(s, ',');



	seq_printf(s, "%u", idx->bit);



	if (idx->pos == idx->weight - 1)

		seq_putc(s, '\n');



	return 0;

}



static const struct seq_operations clusterip_seq_ops = {

	.start	= clusterip_seq_start,

	.next	= clusterip_seq_next,

	.stop	= clusterip_seq_stop,

	.show	= clusterip_seq_show,

};



static int clusterip_proc_open(struct inode *inode, struct file *file)

{

	int ret = seq_open(file, &clusterip_seq_ops);



	if (!ret) {

		struct seq_file *sf = file->private_data;

		struct clusterip_config *c = pde_data(inode);



		sf->private = c;



		clusterip_config_get(c);

	}



	return ret;

}



static int clusterip_proc_release(struct inode *inode, struct file *file)

{

	struct clusterip_config *c = pde_data(inode);

	int ret;



	ret = seq_release(inode, file);



	if (!ret)

		clusterip_config_put(c);



	return ret;

}



static ssize_t clusterip_proc_write(struct file *file, const char __user *input,

				size_t size, loff_t *ofs)

{

	struct clusterip_config *c = pde_data(file_inode(file));

#define PROC_WRITELEN	10

	char buffer[PROC_WRITELEN+1];

	unsigned long nodenum;

	int rc;



	if (size > PROC_WRITELEN)

		return -EIO;

	if (copy_from_user(buffer, input, size))

		return -EFAULT;

	buffer[size] = 0;



	if (*buffer == '+') {

		rc = kstrtoul(buffer+1, 10, &nodenum);

		if (rc)

			return rc;

		if (clusterip_add_node(c, nodenum))

			return -ENOMEM;

	} else if (*buffer == '-') {

		rc = kstrtoul(buffer+1, 10, &nodenum);

		if (rc)

			return rc;

		if (clusterip_del_node(c, nodenum))

			return -ENOENT;

	} else

		return -EIO;



	return size;

}



static const struct proc_ops clusterip_proc_ops = {

	.proc_open	= clusterip_proc_open,

	.proc_read	= seq_read,

	.proc_write	= clusterip_proc_write,

	.proc_lseek	= seq_lseek,

	.proc_release	= clusterip_proc_release,

};



#endif /* CONFIG_PROC_FS */



static int clusterip_net_init(struct net *net)

{

	struct clusterip_net *cn = clusterip_pernet(net);



	INIT_LIST_HEAD(&cn->configs);



	spin_lock_init(&cn->lock);



#ifdef CONFIG_PROC_FS

	cn->procdir = proc_mkdir("ipt_CLUSTERIP", net->proc_net);

	if (!cn->procdir) {

		pr_err("Unable to proc dir entry\n");

		return -ENOMEM;

	}

	mutex_init(&cn->mutex);

#endif /* CONFIG_PROC_FS */



	return 0;

}



static void clusterip_net_exit(struct net *net)

{

#ifdef CONFIG_PROC_FS

	struct clusterip_net *cn = clusterip_pernet(net);



	mutex_lock(&cn->mutex);

	proc_remove(cn->procdir);

	cn->procdir = NULL;

	mutex_unlock(&cn->mutex);

#endif

}



static struct pernet_operations clusterip_net_ops = {

	.init = clusterip_net_init,

	.exit = clusterip_net_exit,

	.id   = &clusterip_net_id,

	.size = sizeof(struct clusterip_net),

};



static struct notifier_block cip_netdev_notifier = {

	.notifier_call = clusterip_netdev_event

};



static int __init clusterip_tg_init(void)

{

	int ret;



	ret = register_pernet_subsys(&clusterip_net_ops);

	if (ret < 0)

		return ret;



	ret = xt_register_target(&clusterip_tg_reg);

	if (ret < 0)

		goto cleanup_subsys;



	ret = register_netdevice_notifier(&cip_netdev_notifier);

	if (ret < 0)

		goto unregister_target;



	pr_info("ClusterIP Version %s loaded successfully\n",

		CLUSTERIP_VERSION);



	return 0;



unregister_target:

	xt_unregister_target(&clusterip_tg_reg);

cleanup_subsys:

	unregister_pernet_subsys(&clusterip_net_ops);

	return ret;

}



static void __exit clusterip_tg_exit(void)

{

	pr_info("ClusterIP Version %s unloading\n", CLUSTERIP_VERSION);



	unregister_netdevice_notifier(&cip_netdev_notifier);

	xt_unregister_target(&clusterip_tg_reg);

	unregister_pernet_subsys(&clusterip_net_ops);



	/* Wait for completion of call_rcu()'s (clusterip_config_rcu_free) */

	rcu_barrier();

}



module_init(clusterip_tg_init);

module_exit(clusterip_tg_exit);