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 (par->nft_compat) {
371		pr_err("cannot use CLUSTERIP target from nftables compat\n");
372		return -EOPNOTSUPP;
373	}
374
375	if (cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP &&
376	    cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP_SPT &&
377	    cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP_SPT_DPT) {
378		pr_info("unknown mode %u\n", cipinfo->hash_mode);
379		return -EINVAL;
380
381	}
382	if (e->ip.dmsk.s_addr != htonl(0xffffffff) ||
383	    e->ip.dst.s_addr == 0) {
384		pr_info("Please specify destination IP\n");
385		return -EINVAL;
386	}
387
388	/* FIXME: further sanity checks */
389
390	config = clusterip_config_find_get(par->net, e->ip.dst.s_addr, 1);
391	if (!config) {
392		if (!(cipinfo->flags & CLUSTERIP_FLAG_NEW)) {
393			pr_info("no config found for %pI4, need 'new'\n",
394				&e->ip.dst.s_addr);
395			return -EINVAL;
396		} else {
397			struct net_device *dev;
398
399			if (e->ip.iniface[0] == '\0') {
400				pr_info("Please specify an interface name\n");
401				return -EINVAL;
402			}
403
404			dev = dev_get_by_name(par->net, e->ip.iniface);
405			if (!dev) {
406				pr_info("no such interface %s\n",
407					e->ip.iniface);
408				return -ENOENT;
409			}
410
411			config = clusterip_config_init(cipinfo,
412							e->ip.dst.s_addr, dev);
413			if (!config) {
414				dev_put(dev);
415				return -ENOMEM;
416			}
417			dev_mc_add(config->dev, config->clustermac);
418		}
419	}
420	cipinfo->config = config;
421
422	ret = nf_ct_l3proto_try_module_get(par->family);
423	if (ret < 0)
424		pr_info("cannot load conntrack support for proto=%u\n",
425			par->family);
426
427	if (!par->net->xt.clusterip_deprecated_warning) {
428		pr_info("ipt_CLUSTERIP is deprecated and it will removed soon, "
429			"use xt_cluster instead\n");
430		par->net->xt.clusterip_deprecated_warning = true;
431	}
432
433	return ret;
434}
435
436/* drop reference count of cluster config when rule is deleted */
437static void clusterip_tg_destroy(const struct xt_tgdtor_param *par)
438{
439	const struct ipt_clusterip_tgt_info *cipinfo = par->targinfo;
440
441	/* if no more entries are referencing the config, remove it
442	 * from the list and destroy the proc entry */
443	clusterip_config_entry_put(cipinfo->config);
444
445	clusterip_config_put(cipinfo->config);
446
447	nf_ct_l3proto_module_put(par->family);
448}
449
450#ifdef CONFIG_COMPAT
451struct compat_ipt_clusterip_tgt_info
452{
453	u_int32_t	flags;
454	u_int8_t	clustermac[6];
455	u_int16_t	num_total_nodes;
456	u_int16_t	num_local_nodes;
457	u_int16_t	local_nodes[CLUSTERIP_MAX_NODES];
458	u_int32_t	hash_mode;
459	u_int32_t	hash_initval;
460	compat_uptr_t	config;
461};
462#endif /* CONFIG_COMPAT */
463
464static struct xt_target clusterip_tg_reg __read_mostly = {
465	.name		= "CLUSTERIP",
466	.family		= NFPROTO_IPV4,
467	.target		= clusterip_tg,
468	.checkentry	= clusterip_tg_check,
469	.destroy	= clusterip_tg_destroy,
470	.targetsize	= sizeof(struct ipt_clusterip_tgt_info),
471#ifdef CONFIG_COMPAT
472	.compatsize	= sizeof(struct compat_ipt_clusterip_tgt_info),
473#endif /* CONFIG_COMPAT */
474	.me		= THIS_MODULE
475};
476
477
478/***********************************************************************
479 * ARP MANGLING CODE
480 ***********************************************************************/
481
482/* hardcoded for 48bit ethernet and 32bit ipv4 addresses */
483struct arp_payload {
484	u_int8_t src_hw[ETH_ALEN];
485	__be32 src_ip;
486	u_int8_t dst_hw[ETH_ALEN];
487	__be32 dst_ip;
488} __packed;
489
490#ifdef DEBUG
491static void arp_print(struct arp_payload *payload)
492{
493#define HBUFFERLEN 30
494	char hbuffer[HBUFFERLEN];
495	int j, k;
496
497	for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < ETH_ALEN; j++) {
498		hbuffer[k++] = hex_asc_hi(payload->src_hw[j]);
499		hbuffer[k++] = hex_asc_lo(payload->src_hw[j]);
500		hbuffer[k++] = ':';
501	}
502	hbuffer[--k] = '\0';
503
504	pr_debug("src %pI4@%s, dst %pI4\n",
505		 &payload->src_ip, hbuffer, &payload->dst_ip);
506}
507#endif
508
509static unsigned int
510arp_mangle(void *priv,
511	   struct sk_buff *skb,
512	   const struct nf_hook_state *state)
513{
514	struct arphdr *arp = arp_hdr(skb);
515	struct arp_payload *payload;
516	struct clusterip_config *c;
517	struct net *net = state->net;
518
519	/* we don't care about non-ethernet and non-ipv4 ARP */
520	if (arp->ar_hrd != htons(ARPHRD_ETHER) ||
521	    arp->ar_pro != htons(ETH_P_IP) ||
522	    arp->ar_pln != 4 || arp->ar_hln != ETH_ALEN)
523		return NF_ACCEPT;
524
525	/* we only want to mangle arp requests and replies */
526	if (arp->ar_op != htons(ARPOP_REPLY) &&
527	    arp->ar_op != htons(ARPOP_REQUEST))
528		return NF_ACCEPT;
529
530	payload = (void *)(arp+1);
531
532	/* if there is no clusterip configuration for the arp reply's
533	 * source ip, we don't want to mangle it */
534	c = clusterip_config_find_get(net, payload->src_ip, 0);
535	if (!c)
536		return NF_ACCEPT;
537
538	/* normally the linux kernel always replies to arp queries of
539	 * addresses on different interfacs.  However, in the CLUSTERIP case
540	 * this wouldn't work, since we didn't subscribe the mcast group on
541	 * other interfaces */
542	if (c->dev != state->out) {
543		pr_debug("not mangling arp reply on different "
544			 "interface: cip'%s'-skb'%s'\n",
545			 c->dev->name, state->out->name);
546		clusterip_config_put(c);
547		return NF_ACCEPT;
548	}
549
550	/* mangle reply hardware address */
551	memcpy(payload->src_hw, c->clustermac, arp->ar_hln);
552
553#ifdef DEBUG
554	pr_debug("mangled arp reply: ");
555	arp_print(payload);
556#endif
557
558	clusterip_config_put(c);
559
560	return NF_ACCEPT;
561}
562
563static struct nf_hook_ops cip_arp_ops __read_mostly = {
564	.hook = arp_mangle,
565	.pf = NFPROTO_ARP,
566	.hooknum = NF_ARP_OUT,
567	.priority = -1
568};
569
570/***********************************************************************
571 * PROC DIR HANDLING
572 ***********************************************************************/
573
574#ifdef CONFIG_PROC_FS
575
576struct clusterip_seq_position {
577	unsigned int pos;	/* position */
578	unsigned int weight;	/* number of bits set == size */
579	unsigned int bit;	/* current bit */
580	unsigned long val;	/* current value */
581};
582
583static void *clusterip_seq_start(struct seq_file *s, loff_t *pos)
584{
585	struct clusterip_config *c = s->private;
586	unsigned int weight;
587	u_int32_t local_nodes;
588	struct clusterip_seq_position *idx;
589
590	/* FIXME: possible race */
591	local_nodes = c->local_nodes;
592	weight = hweight32(local_nodes);
593	if (*pos >= weight)
594		return NULL;
595
596	idx = kmalloc(sizeof(struct clusterip_seq_position), GFP_KERNEL);
597	if (!idx)
598		return ERR_PTR(-ENOMEM);
599
600	idx->pos = *pos;
601	idx->weight = weight;
602	idx->bit = ffs(local_nodes);
603	idx->val = local_nodes;
604	clear_bit(idx->bit - 1, &idx->val);
605
606	return idx;
607}
608
609static void *clusterip_seq_next(struct seq_file *s, void *v, loff_t *pos)
610{
611	struct clusterip_seq_position *idx = v;
612
613	*pos = ++idx->pos;
614	if (*pos >= idx->weight) {
615		kfree(v);
616		return NULL;
617	}
618	idx->bit = ffs(idx->val);
619	clear_bit(idx->bit - 1, &idx->val);
620	return idx;
621}
622
623static void clusterip_seq_stop(struct seq_file *s, void *v)
624{
625	if (!IS_ERR(v))
626		kfree(v);
627}
628
629static int clusterip_seq_show(struct seq_file *s, void *v)
630{
631	struct clusterip_seq_position *idx = v;
632
633	if (idx->pos != 0)
634		seq_putc(s, ',');
635
636	seq_printf(s, "%u", idx->bit);
637
638	if (idx->pos == idx->weight - 1)
639		seq_putc(s, '\n');
640
641	return 0;
642}
643
644static const struct seq_operations clusterip_seq_ops = {
645	.start	= clusterip_seq_start,
646	.next	= clusterip_seq_next,
647	.stop	= clusterip_seq_stop,
648	.show	= clusterip_seq_show,
649};
650
651static int clusterip_proc_open(struct inode *inode, struct file *file)
652{
653	int ret = seq_open(file, &clusterip_seq_ops);
654
655	if (!ret) {
656		struct seq_file *sf = file->private_data;
657		struct clusterip_config *c = PDE_DATA(inode);
658
659		sf->private = c;
660
661		clusterip_config_get(c);
662	}
663
664	return ret;
665}
666
667static int clusterip_proc_release(struct inode *inode, struct file *file)
668{
669	struct clusterip_config *c = PDE_DATA(inode);
670	int ret;
671
672	ret = seq_release(inode, file);
673
674	if (!ret)
675		clusterip_config_put(c);
676
677	return ret;
678}
679
680static ssize_t clusterip_proc_write(struct file *file, const char __user *input,
681				size_t size, loff_t *ofs)
682{
683	struct clusterip_config *c = PDE_DATA(file_inode(file));
684#define PROC_WRITELEN	10
685	char buffer[PROC_WRITELEN+1];
686	unsigned long nodenum;
687	int rc;
688
689	if (size > PROC_WRITELEN)
690		return -EIO;
691	if (copy_from_user(buffer, input, size))
692		return -EFAULT;
693	buffer[size] = 0;
694
695	if (*buffer == '+') {
696		rc = kstrtoul(buffer+1, 10, &nodenum);
697		if (rc)
698			return rc;
699		if (clusterip_add_node(c, nodenum))
700			return -ENOMEM;
701	} else if (*buffer == '-') {
702		rc = kstrtoul(buffer+1, 10, &nodenum);
703		if (rc)
704			return rc;
705		if (clusterip_del_node(c, nodenum))
706			return -ENOENT;
707	} else
708		return -EIO;
709
710	return size;
711}
712
713static const struct file_operations clusterip_proc_fops = {
714	.owner	 = THIS_MODULE,
715	.open	 = clusterip_proc_open,
716	.read	 = seq_read,
717	.write	 = clusterip_proc_write,
718	.llseek	 = seq_lseek,
719	.release = clusterip_proc_release,
720};
721
722#endif /* CONFIG_PROC_FS */
723
724static int clusterip_net_init(struct net *net)
725{
726	struct clusterip_net *cn = net_generic(net, clusterip_net_id);
727
728	INIT_LIST_HEAD(&cn->configs);
729
730	spin_lock_init(&cn->lock);
731
732#ifdef CONFIG_PROC_FS
733	cn->procdir = proc_mkdir("ipt_CLUSTERIP", net->proc_net);
734	if (!cn->procdir) {
735		pr_err("Unable to proc dir entry\n");
736		return -ENOMEM;
737	}
738#endif /* CONFIG_PROC_FS */
739
740	return 0;
741}
742
743static void clusterip_net_exit(struct net *net)
744{
745#ifdef CONFIG_PROC_FS
746	struct clusterip_net *cn = net_generic(net, clusterip_net_id);
747	proc_remove(cn->procdir);
748#endif
749}
750
751static struct pernet_operations clusterip_net_ops = {
752	.init = clusterip_net_init,
753	.exit = clusterip_net_exit,
754	.id   = &clusterip_net_id,
755	.size = sizeof(struct clusterip_net),
756};
757
758static int __init clusterip_tg_init(void)
759{
760	int ret;
761
762	ret = register_pernet_subsys(&clusterip_net_ops);
763	if (ret < 0)
764		return ret;
765
766	ret = xt_register_target(&clusterip_tg_reg);
767	if (ret < 0)
768		goto cleanup_subsys;
769
770	ret = nf_register_hook(&cip_arp_ops);
771	if (ret < 0)
772		goto cleanup_target;
773
774	pr_info("ClusterIP Version %s loaded successfully\n",
775		CLUSTERIP_VERSION);
776
777	return 0;
778
779cleanup_target:
780	xt_unregister_target(&clusterip_tg_reg);
781cleanup_subsys:
782	unregister_pernet_subsys(&clusterip_net_ops);
783	return ret;
784}
785
786static void __exit clusterip_tg_exit(void)
787{
788	pr_info("ClusterIP Version %s unloading\n", CLUSTERIP_VERSION);
789
790	nf_unregister_hook(&cip_arp_ops);
791	xt_unregister_target(&clusterip_tg_reg);
792	unregister_pernet_subsys(&clusterip_net_ops);
793
794	/* Wait for completion of call_rcu_bh()'s (clusterip_config_rcu_free) */
795	rcu_barrier_bh();
796}
797
798module_init(clusterip_tg_init);
799module_exit(clusterip_tg_exit);
800