1/* Cluster IP hashmark target
2 * (C) 2003-2004 by Harald Welte <laforge@netfilter.org>
3 * based on ideas of Fabio Olive Leite <olive@unixforge.org>
4 *
5 * Development of this code funded by SuSE Linux AG, http://www.suse.com/
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 */
12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13#include <linux/module.h>
14#include <linux/proc_fs.h>
15#include <linux/jhash.h>
16#include <linux/bitops.h>
17#include <linux/skbuff.h>
18#include <linux/slab.h>
19#include <linux/ip.h>
20#include <linux/tcp.h>
21#include <linux/udp.h>
22#include <linux/icmp.h>
23#include <linux/if_arp.h>
24#include <linux/seq_file.h>
25#include <linux/netfilter_arp.h>
26#include <linux/netfilter/x_tables.h>
27#include <linux/netfilter_ipv4/ip_tables.h>
28#include <linux/netfilter_ipv4/ipt_CLUSTERIP.h>
29#include <net/netfilter/nf_conntrack.h>
30#include <net/net_namespace.h>
31#include <net/netns/generic.h>
32#include <net/checksum.h>
33#include <net/ip.h>
34
35#define CLUSTERIP_VERSION "0.8"
36
37MODULE_LICENSE("GPL");
38MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
39MODULE_DESCRIPTION("Xtables: CLUSTERIP target");
40
41struct clusterip_config {
42	struct list_head list;			/* list of all configs */
43	atomic_t refcount;			/* reference count */
44	atomic_t entries;			/* number of entries/rules
45						 * referencing us */
46
47	__be32 clusterip;			/* the IP address */
48	u_int8_t clustermac[ETH_ALEN];		/* the MAC address */
49	struct net_device *dev;			/* device */
50	u_int16_t num_total_nodes;		/* total number of nodes */
51	unsigned long local_nodes;		/* node number array */
52
53#ifdef CONFIG_PROC_FS
54	struct proc_dir_entry *pde;		/* proc dir entry */
55#endif
56	enum clusterip_hashmode hash_mode;	/* which hashing mode */
57	u_int32_t hash_initval;			/* hash initialization */
58	struct rcu_head rcu;
59};
60
61#ifdef CONFIG_PROC_FS
62static const struct file_operations clusterip_proc_fops;
63#endif
64
65static int clusterip_net_id __read_mostly;
66
67struct clusterip_net {
68	struct list_head configs;
69	/* lock protects the configs list */
70	spinlock_t lock;
71
72#ifdef CONFIG_PROC_FS
73	struct proc_dir_entry *procdir;
74#endif
75};
76
77static inline void
78clusterip_config_get(struct clusterip_config *c)
79{
80	atomic_inc(&c->refcount);
81}
82
83
84static void clusterip_config_rcu_free(struct rcu_head *head)
85{
86	kfree(container_of(head, struct clusterip_config, rcu));
87}
88
89static inline void
90clusterip_config_put(struct clusterip_config *c)
91{
92	if (atomic_dec_and_test(&c->refcount))
93		call_rcu_bh(&c->rcu, clusterip_config_rcu_free);
94}
95
96/* decrease the count of entries using/referencing this config.  If last
97 * entry(rule) is removed, remove the config from lists, but don't free it
98 * yet, since proc-files could still be holding references */
99static inline void
100clusterip_config_entry_put(struct clusterip_config *c)
101{
102	struct net *net = dev_net(c->dev);
103	struct clusterip_net *cn = net_generic(net, clusterip_net_id);
104
105	local_bh_disable();
106	if (atomic_dec_and_lock(&c->entries, &cn->lock)) {
107		list_del_rcu(&c->list);
108		spin_unlock(&cn->lock);
109		local_bh_enable();
110
111		dev_mc_del(c->dev, c->clustermac);
112		dev_put(c->dev);
113
114		/* In case anyone still accesses the file, the open/close
115		 * functions are also incrementing the refcount on their own,
116		 * so it's safe to remove the entry even if it's in use. */
117#ifdef CONFIG_PROC_FS
118		proc_remove(c->pde);
119#endif
120		return;
121	}
122	local_bh_enable();
123}
124
125static struct clusterip_config *
126__clusterip_config_find(struct net *net, __be32 clusterip)
127{
128	struct clusterip_config *c;
129	struct clusterip_net *cn = net_generic(net, clusterip_net_id);
130
131	list_for_each_entry_rcu(c, &cn->configs, list) {
132		if (c->clusterip == clusterip)
133			return c;
134	}
135
136	return NULL;
137}
138
139static inline struct clusterip_config *
140clusterip_config_find_get(struct net *net, __be32 clusterip, int entry)
141{
142	struct clusterip_config *c;
143
144	rcu_read_lock_bh();
145	c = __clusterip_config_find(net, clusterip);
146	if (c) {
147		if (unlikely(!atomic_inc_not_zero(&c->refcount)))
148			c = NULL;
149		else if (entry)
150			atomic_inc(&c->entries);
151	}
152	rcu_read_unlock_bh();
153
154	return c;
155}
156
157static void
158clusterip_config_init_nodelist(struct clusterip_config *c,
159			       const struct ipt_clusterip_tgt_info *i)
160{
161	int n;
162
163	for (n = 0; n < i->num_local_nodes; n++)
164		set_bit(i->local_nodes[n] - 1, &c->local_nodes);
165}
166
167static struct clusterip_config *
168clusterip_config_init(const struct ipt_clusterip_tgt_info *i, __be32 ip,
169			struct net_device *dev)
170{
171	struct clusterip_config *c;
172	struct clusterip_net *cn = net_generic(dev_net(dev), clusterip_net_id);
173
174	c = kzalloc(sizeof(*c), GFP_ATOMIC);
175	if (!c)
176		return NULL;
177
178	c->dev = dev;
179	c->clusterip = ip;
180	memcpy(&c->clustermac, &i->clustermac, ETH_ALEN);
181	c->num_total_nodes = i->num_total_nodes;
182	clusterip_config_init_nodelist(c, i);
183	c->hash_mode = i->hash_mode;
184	c->hash_initval = i->hash_initval;
185	atomic_set(&c->refcount, 1);
186	atomic_set(&c->entries, 1);
187
188#ifdef CONFIG_PROC_FS
189	{
190		char buffer[16];
191
192		/* create proc dir entry */
193		sprintf(buffer, "%pI4", &ip);
194		c->pde = proc_create_data(buffer, S_IWUSR|S_IRUSR,
195					  cn->procdir,
196					  &clusterip_proc_fops, c);
197		if (!c->pde) {
198			kfree(c);
199			return NULL;
200		}
201	}
202#endif
203
204	spin_lock_bh(&cn->lock);
205	list_add_rcu(&c->list, &cn->configs);
206	spin_unlock_bh(&cn->lock);
207
208	return c;
209}
210
211#ifdef CONFIG_PROC_FS
212static int
213clusterip_add_node(struct clusterip_config *c, u_int16_t nodenum)
214{
215
216	if (nodenum == 0 ||
217	    nodenum > c->num_total_nodes)
218		return 1;
219
220	/* check if we already have this number in our bitfield */
221	if (test_and_set_bit(nodenum - 1, &c->local_nodes))
222		return 1;
223
224	return 0;
225}
226
227static bool
228clusterip_del_node(struct clusterip_config *c, u_int16_t nodenum)
229{
230	if (nodenum == 0 ||
231	    nodenum > c->num_total_nodes)
232		return true;
233
234	if (test_and_clear_bit(nodenum - 1, &c->local_nodes))
235		return false;
236
237	return true;
238}
239#endif
240
241static inline u_int32_t
242clusterip_hashfn(const struct sk_buff *skb,
243		 const struct clusterip_config *config)
244{
245	const struct iphdr *iph = ip_hdr(skb);
246	unsigned long hashval;
247	u_int16_t sport = 0, dport = 0;
248	int poff;
249
250	poff = proto_ports_offset(iph->protocol);
251	if (poff >= 0) {
252		const u_int16_t *ports;
253		u16 _ports[2];
254
255		ports = skb_header_pointer(skb, iph->ihl * 4 + poff, 4, _ports);
256		if (ports) {
257			sport = ports[0];
258			dport = ports[1];
259		}
260	} else {
261		net_info_ratelimited("unknown protocol %u\n", iph->protocol);
262	}
263
264	switch (config->hash_mode) {
265	case CLUSTERIP_HASHMODE_SIP:
266		hashval = jhash_1word(ntohl(iph->saddr),
267				      config->hash_initval);
268		break;
269	case CLUSTERIP_HASHMODE_SIP_SPT:
270		hashval = jhash_2words(ntohl(iph->saddr), sport,
271				       config->hash_initval);
272		break;
273	case CLUSTERIP_HASHMODE_SIP_SPT_DPT:
274		hashval = jhash_3words(ntohl(iph->saddr), sport, dport,
275				       config->hash_initval);
276		break;
277	default:
278		/* to make gcc happy */
279		hashval = 0;
280		/* This cannot happen, unless the check function wasn't called
281		 * at rule load time */
282		pr_info("unknown mode %u\n", config->hash_mode);
283		BUG();
284		break;
285	}
286
287	/* node numbers are 1..n, not 0..n */
288	return reciprocal_scale(hashval, config->num_total_nodes) + 1;
289}
290
291static inline int
292clusterip_responsible(const struct clusterip_config *config, u_int32_t hash)
293{
294	return test_bit(hash - 1, &config->local_nodes);
295}
296
297/***********************************************************************
298 * IPTABLES TARGET
299 ***********************************************************************/
300
301static unsigned int
302clusterip_tg(struct sk_buff *skb, const struct xt_action_param *par)
303{
304	const struct ipt_clusterip_tgt_info *cipinfo = par->targinfo;
305	struct nf_conn *ct;
306	enum ip_conntrack_info ctinfo;
307	u_int32_t hash;
308
309	/* don't need to clusterip_config_get() here, since refcount
310	 * is only decremented by destroy() - and ip_tables guarantees
311	 * that the ->target() function isn't called after ->destroy() */
312
313	ct = nf_ct_get(skb, &ctinfo);
314	if (ct == NULL)
315		return NF_DROP;
316
317	/* special case: ICMP error handling. conntrack distinguishes between
318	 * error messages (RELATED) and information requests (see below) */
319	if (ip_hdr(skb)->protocol == IPPROTO_ICMP &&
320	    (ctinfo == IP_CT_RELATED ||
321	     ctinfo == IP_CT_RELATED_REPLY))
322		return XT_CONTINUE;
323
324	/* ip_conntrack_icmp guarantees us that we only have ICMP_ECHO,
325	 * TIMESTAMP, INFO_REQUEST or ADDRESS type icmp packets from here
326	 * on, which all have an ID field [relevant for hashing]. */
327
328	hash = clusterip_hashfn(skb, cipinfo->config);
329
330	switch (ctinfo) {
331	case IP_CT_NEW:
332		ct->mark = hash;
333		break;
334	case IP_CT_RELATED:
335	case IP_CT_RELATED_REPLY:
336		/* FIXME: we don't handle expectations at the moment.
337		 * They can arrive on a different node than
338		 * the master connection (e.g. FTP passive mode) */
339	case IP_CT_ESTABLISHED:
340	case IP_CT_ESTABLISHED_REPLY:
341		break;
342	default:			/* Prevent gcc warnings */
343		break;
344	}
345
346#ifdef DEBUG
347	nf_ct_dump_tuple_ip(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
348#endif
349	pr_debug("hash=%u ct_hash=%u ", hash, ct->mark);
350	if (!clusterip_responsible(cipinfo->config, hash)) {
351		pr_debug("not responsible\n");
352		return NF_DROP;
353	}
354	pr_debug("responsible\n");
355
356	/* despite being received via linklayer multicast, this is
357	 * actually a unicast IP packet. TCP doesn't like PACKET_MULTICAST */
358	skb->pkt_type = PACKET_HOST;
359
360	return XT_CONTINUE;
361}
362
363static int clusterip_tg_check(const struct xt_tgchk_param *par)
364{
365	struct ipt_clusterip_tgt_info *cipinfo = par->targinfo;
366	const struct ipt_entry *e = par->entryinfo;
367	struct clusterip_config *config;
368	int ret;
369
370	if (cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP &&
371	    cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP_SPT &&
372	    cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP_SPT_DPT) {
373		pr_info("unknown mode %u\n", cipinfo->hash_mode);
374		return -EINVAL;
375
376	}
377	if (e->ip.dmsk.s_addr != htonl(0xffffffff) ||
378	    e->ip.dst.s_addr == 0) {
379		pr_info("Please specify destination IP\n");
380		return -EINVAL;
381	}
382
383	/* FIXME: further sanity checks */
384
385	config = clusterip_config_find_get(par->net, e->ip.dst.s_addr, 1);
386	if (!config) {
387		if (!(cipinfo->flags & CLUSTERIP_FLAG_NEW)) {
388			pr_info("no config found for %pI4, need 'new'\n",
389				&e->ip.dst.s_addr);
390			return -EINVAL;
391		} else {
392			struct net_device *dev;
393
394			if (e->ip.iniface[0] == '\0') {
395				pr_info("Please specify an interface name\n");
396				return -EINVAL;
397			}
398
399			dev = dev_get_by_name(par->net, e->ip.iniface);
400			if (!dev) {
401				pr_info("no such interface %s\n",
402					e->ip.iniface);
403				return -ENOENT;
404			}
405
406			config = clusterip_config_init(cipinfo,
407							e->ip.dst.s_addr, dev);
408			if (!config) {
409				dev_put(dev);
410				return -ENOMEM;
411			}
412			dev_mc_add(config->dev, config->clustermac);
413		}
414	}
415	cipinfo->config = config;
416
417	ret = nf_ct_l3proto_try_module_get(par->family);
418	if (ret < 0)
419		pr_info("cannot load conntrack support for proto=%u\n",
420			par->family);
421
422	if (!par->net->xt.clusterip_deprecated_warning) {
423		pr_info("ipt_CLUSTERIP is deprecated and it will removed soon, "
424			"use xt_cluster instead\n");
425		par->net->xt.clusterip_deprecated_warning = true;
426	}
427
428	return ret;
429}
430
431/* drop reference count of cluster config when rule is deleted */
432static void clusterip_tg_destroy(const struct xt_tgdtor_param *par)
433{
434	const struct ipt_clusterip_tgt_info *cipinfo = par->targinfo;
435
436	/* if no more entries are referencing the config, remove it
437	 * from the list and destroy the proc entry */
438	clusterip_config_entry_put(cipinfo->config);
439
440	clusterip_config_put(cipinfo->config);
441
442	nf_ct_l3proto_module_put(par->family);
443}
444
445#ifdef CONFIG_COMPAT
446struct compat_ipt_clusterip_tgt_info
447{
448	u_int32_t	flags;
449	u_int8_t	clustermac[6];
450	u_int16_t	num_total_nodes;
451	u_int16_t	num_local_nodes;
452	u_int16_t	local_nodes[CLUSTERIP_MAX_NODES];
453	u_int32_t	hash_mode;
454	u_int32_t	hash_initval;
455	compat_uptr_t	config;
456};
457#endif /* CONFIG_COMPAT */
458
459static struct xt_target clusterip_tg_reg __read_mostly = {
460	.name		= "CLUSTERIP",
461	.family		= NFPROTO_IPV4,
462	.target		= clusterip_tg,
463	.checkentry	= clusterip_tg_check,
464	.destroy	= clusterip_tg_destroy,
465	.targetsize	= sizeof(struct ipt_clusterip_tgt_info),
466#ifdef CONFIG_COMPAT
467	.compatsize	= sizeof(struct compat_ipt_clusterip_tgt_info),
468#endif /* CONFIG_COMPAT */
469	.me		= THIS_MODULE
470};
471
472
473/***********************************************************************
474 * ARP MANGLING CODE
475 ***********************************************************************/
476
477/* hardcoded for 48bit ethernet and 32bit ipv4 addresses */
478struct arp_payload {
479	u_int8_t src_hw[ETH_ALEN];
480	__be32 src_ip;
481	u_int8_t dst_hw[ETH_ALEN];
482	__be32 dst_ip;
483} __packed;
484
485#ifdef DEBUG
486static void arp_print(struct arp_payload *payload)
487{
488#define HBUFFERLEN 30
489	char hbuffer[HBUFFERLEN];
490	int j,k;
491
492	for (k=0, j=0; k < HBUFFERLEN-3 && j < ETH_ALEN; j++) {
493		hbuffer[k++] = hex_asc_hi(payload->src_hw[j]);
494		hbuffer[k++] = hex_asc_lo(payload->src_hw[j]);
495		hbuffer[k++]=':';
496	}
497	hbuffer[--k]='\0';
498
499	pr_debug("src %pI4@%s, dst %pI4\n",
500		 &payload->src_ip, hbuffer, &payload->dst_ip);
501}
502#endif
503
504static unsigned int
505arp_mangle(const struct nf_hook_ops *ops,
506	   struct sk_buff *skb,
507	   const struct nf_hook_state *state)
508{
509	struct arphdr *arp = arp_hdr(skb);
510	struct arp_payload *payload;
511	struct clusterip_config *c;
512	struct net *net = dev_net(state->in ? state->in : state->out);
513
514	/* we don't care about non-ethernet and non-ipv4 ARP */
515	if (arp->ar_hrd != htons(ARPHRD_ETHER) ||
516	    arp->ar_pro != htons(ETH_P_IP) ||
517	    arp->ar_pln != 4 || arp->ar_hln != ETH_ALEN)
518		return NF_ACCEPT;
519
520	/* we only want to mangle arp requests and replies */
521	if (arp->ar_op != htons(ARPOP_REPLY) &&
522	    arp->ar_op != htons(ARPOP_REQUEST))
523		return NF_ACCEPT;
524
525	payload = (void *)(arp+1);
526
527	/* if there is no clusterip configuration for the arp reply's
528	 * source ip, we don't want to mangle it */
529	c = clusterip_config_find_get(net, payload->src_ip, 0);
530	if (!c)
531		return NF_ACCEPT;
532
533	/* normally the linux kernel always replies to arp queries of
534	 * addresses on different interfacs.  However, in the CLUSTERIP case
535	 * this wouldn't work, since we didn't subscribe the mcast group on
536	 * other interfaces */
537	if (c->dev != state->out) {
538		pr_debug("not mangling arp reply on different "
539			 "interface: cip'%s'-skb'%s'\n",
540			 c->dev->name, state->out->name);
541		clusterip_config_put(c);
542		return NF_ACCEPT;
543	}
544
545	/* mangle reply hardware address */
546	memcpy(payload->src_hw, c->clustermac, arp->ar_hln);
547
548#ifdef DEBUG
549	pr_debug("mangled arp reply: ");
550	arp_print(payload);
551#endif
552
553	clusterip_config_put(c);
554
555	return NF_ACCEPT;
556}
557
558static struct nf_hook_ops cip_arp_ops __read_mostly = {
559	.hook = arp_mangle,
560	.pf = NFPROTO_ARP,
561	.hooknum = NF_ARP_OUT,
562	.priority = -1
563};
564
565/***********************************************************************
566 * PROC DIR HANDLING
567 ***********************************************************************/
568
569#ifdef CONFIG_PROC_FS
570
571struct clusterip_seq_position {
572	unsigned int pos;	/* position */
573	unsigned int weight;	/* number of bits set == size */
574	unsigned int bit;	/* current bit */
575	unsigned long val;	/* current value */
576};
577
578static void *clusterip_seq_start(struct seq_file *s, loff_t *pos)
579{
580	struct clusterip_config *c = s->private;
581	unsigned int weight;
582	u_int32_t local_nodes;
583	struct clusterip_seq_position *idx;
584
585	/* FIXME: possible race */
586	local_nodes = c->local_nodes;
587	weight = hweight32(local_nodes);
588	if (*pos >= weight)
589		return NULL;
590
591	idx = kmalloc(sizeof(struct clusterip_seq_position), GFP_KERNEL);
592	if (!idx)
593		return ERR_PTR(-ENOMEM);
594
595	idx->pos = *pos;
596	idx->weight = weight;
597	idx->bit = ffs(local_nodes);
598	idx->val = local_nodes;
599	clear_bit(idx->bit - 1, &idx->val);
600
601	return idx;
602}
603
604static void *clusterip_seq_next(struct seq_file *s, void *v, loff_t *pos)
605{
606	struct clusterip_seq_position *idx = v;
607
608	*pos = ++idx->pos;
609	if (*pos >= idx->weight) {
610		kfree(v);
611		return NULL;
612	}
613	idx->bit = ffs(idx->val);
614	clear_bit(idx->bit - 1, &idx->val);
615	return idx;
616}
617
618static void clusterip_seq_stop(struct seq_file *s, void *v)
619{
620	if (!IS_ERR(v))
621		kfree(v);
622}
623
624static int clusterip_seq_show(struct seq_file *s, void *v)
625{
626	struct clusterip_seq_position *idx = v;
627
628	if (idx->pos != 0)
629		seq_putc(s, ',');
630
631	seq_printf(s, "%u", idx->bit);
632
633	if (idx->pos == idx->weight - 1)
634		seq_putc(s, '\n');
635
636	return 0;
637}
638
639static const struct seq_operations clusterip_seq_ops = {
640	.start	= clusterip_seq_start,
641	.next	= clusterip_seq_next,
642	.stop	= clusterip_seq_stop,
643	.show	= clusterip_seq_show,
644};
645
646static int clusterip_proc_open(struct inode *inode, struct file *file)
647{
648	int ret = seq_open(file, &clusterip_seq_ops);
649
650	if (!ret) {
651		struct seq_file *sf = file->private_data;
652		struct clusterip_config *c = PDE_DATA(inode);
653
654		sf->private = c;
655
656		clusterip_config_get(c);
657	}
658
659	return ret;
660}
661
662static int clusterip_proc_release(struct inode *inode, struct file *file)
663{
664	struct clusterip_config *c = PDE_DATA(inode);
665	int ret;
666
667	ret = seq_release(inode, file);
668
669	if (!ret)
670		clusterip_config_put(c);
671
672	return ret;
673}
674
675static ssize_t clusterip_proc_write(struct file *file, const char __user *input,
676				size_t size, loff_t *ofs)
677{
678	struct clusterip_config *c = PDE_DATA(file_inode(file));
679#define PROC_WRITELEN	10
680	char buffer[PROC_WRITELEN+1];
681	unsigned long nodenum;
682	int rc;
683
684	if (size > PROC_WRITELEN)
685		return -EIO;
686	if (copy_from_user(buffer, input, size))
687		return -EFAULT;
688	buffer[size] = 0;
689
690	if (*buffer == '+') {
691		rc = kstrtoul(buffer+1, 10, &nodenum);
692		if (rc)
693			return rc;
694		if (clusterip_add_node(c, nodenum))
695			return -ENOMEM;
696	} else if (*buffer == '-') {
697		rc = kstrtoul(buffer+1, 10, &nodenum);
698		if (rc)
699			return rc;
700		if (clusterip_del_node(c, nodenum))
701			return -ENOENT;
702	} else
703		return -EIO;
704
705	return size;
706}
707
708static const struct file_operations clusterip_proc_fops = {
709	.owner	 = THIS_MODULE,
710	.open	 = clusterip_proc_open,
711	.read	 = seq_read,
712	.write	 = clusterip_proc_write,
713	.llseek	 = seq_lseek,
714	.release = clusterip_proc_release,
715};
716
717#endif /* CONFIG_PROC_FS */
718
719static int clusterip_net_init(struct net *net)
720{
721	struct clusterip_net *cn = net_generic(net, clusterip_net_id);
722
723	INIT_LIST_HEAD(&cn->configs);
724
725	spin_lock_init(&cn->lock);
726
727#ifdef CONFIG_PROC_FS
728	cn->procdir = proc_mkdir("ipt_CLUSTERIP", net->proc_net);
729	if (!cn->procdir) {
730		pr_err("Unable to proc dir entry\n");
731		return -ENOMEM;
732	}
733#endif /* CONFIG_PROC_FS */
734
735	return 0;
736}
737
738static void clusterip_net_exit(struct net *net)
739{
740#ifdef CONFIG_PROC_FS
741	struct clusterip_net *cn = net_generic(net, clusterip_net_id);
742	proc_remove(cn->procdir);
743#endif
744}
745
746static struct pernet_operations clusterip_net_ops = {
747	.init = clusterip_net_init,
748	.exit = clusterip_net_exit,
749	.id   = &clusterip_net_id,
750	.size = sizeof(struct clusterip_net),
751};
752
753static int __init clusterip_tg_init(void)
754{
755	int ret;
756
757	ret = register_pernet_subsys(&clusterip_net_ops);
758	if (ret < 0)
759		return ret;
760
761	ret = xt_register_target(&clusterip_tg_reg);
762	if (ret < 0)
763		goto cleanup_subsys;
764
765	ret = nf_register_hook(&cip_arp_ops);
766	if (ret < 0)
767		goto cleanup_target;
768
769	pr_info("ClusterIP Version %s loaded successfully\n",
770		CLUSTERIP_VERSION);
771
772	return 0;
773
774cleanup_target:
775	xt_unregister_target(&clusterip_tg_reg);
776cleanup_subsys:
777	unregister_pernet_subsys(&clusterip_net_ops);
778	return ret;
779}
780
781static void __exit clusterip_tg_exit(void)
782{
783	pr_info("ClusterIP Version %s unloading\n", CLUSTERIP_VERSION);
784
785	nf_unregister_hook(&cip_arp_ops);
786	xt_unregister_target(&clusterip_tg_reg);
787	unregister_pernet_subsys(&clusterip_net_ops);
788
789	/* Wait for completion of call_rcu_bh()'s (clusterip_config_rcu_free) */
790	rcu_barrier_bh();
791}
792
793module_init(clusterip_tg_init);
794module_exit(clusterip_tg_exit);
795