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TOMOYO Linux Cross Reference
Linux/net/ipv4/netfilter/ipt_CLUSTERIP.c

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  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/checksum.h>
 32 #include <net/ip.h>
 33 
 34 #define CLUSTERIP_VERSION "0.8"
 35 
 36 MODULE_LICENSE("GPL");
 37 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
 38 MODULE_DESCRIPTION("Xtables: CLUSTERIP target");
 39 
 40 struct clusterip_config {
 41         struct list_head list;                  /* list of all configs */
 42         atomic_t refcount;                      /* reference count */
 43         atomic_t entries;                       /* number of entries/rules
 44                                                  * referencing us */
 45 
 46         __be32 clusterip;                       /* the IP address */
 47         u_int8_t clustermac[ETH_ALEN];          /* the MAC address */
 48         struct net_device *dev;                 /* device */
 49         u_int16_t num_total_nodes;              /* total number of nodes */
 50         unsigned long local_nodes;              /* node number array */
 51 
 52 #ifdef CONFIG_PROC_FS
 53         struct proc_dir_entry *pde;             /* proc dir entry */
 54 #endif
 55         enum clusterip_hashmode hash_mode;      /* which hashing mode */
 56         u_int32_t hash_initval;                 /* hash initialization */
 57         struct rcu_head rcu;
 58 };
 59 
 60 static LIST_HEAD(clusterip_configs);
 61 
 62 /* clusterip_lock protects the clusterip_configs list */
 63 static DEFINE_SPINLOCK(clusterip_lock);
 64 
 65 #ifdef CONFIG_PROC_FS
 66 static const struct file_operations clusterip_proc_fops;
 67 static struct proc_dir_entry *clusterip_procdir;
 68 #endif
 69 
 70 static inline void
 71 clusterip_config_get(struct clusterip_config *c)
 72 {
 73         atomic_inc(&c->refcount);
 74 }
 75 
 76 
 77 static void clusterip_config_rcu_free(struct rcu_head *head)
 78 {
 79         kfree(container_of(head, struct clusterip_config, rcu));
 80 }
 81 
 82 static inline void
 83 clusterip_config_put(struct clusterip_config *c)
 84 {
 85         if (atomic_dec_and_test(&c->refcount))
 86                 call_rcu_bh(&c->rcu, clusterip_config_rcu_free);
 87 }
 88 
 89 /* decrease the count of entries using/referencing this config.  If last
 90  * entry(rule) is removed, remove the config from lists, but don't free it
 91  * yet, since proc-files could still be holding references */
 92 static inline void
 93 clusterip_config_entry_put(struct clusterip_config *c)
 94 {
 95         local_bh_disable();
 96         if (atomic_dec_and_lock(&c->entries, &clusterip_lock)) {
 97                 list_del_rcu(&c->list);
 98                 spin_unlock(&clusterip_lock);
 99                 local_bh_enable();
100 
101                 dev_mc_del(c->dev, c->clustermac);
102                 dev_put(c->dev);
103 
104                 /* In case anyone still accesses the file, the open/close
105                  * functions are also incrementing the refcount on their own,
106                  * so it's safe to remove the entry even if it's in use. */
107 #ifdef CONFIG_PROC_FS
108                 remove_proc_entry(c->pde->name, c->pde->parent);
109 #endif
110                 return;
111         }
112         local_bh_enable();
113 }
114 
115 static struct clusterip_config *
116 __clusterip_config_find(__be32 clusterip)
117 {
118         struct clusterip_config *c;
119 
120         list_for_each_entry_rcu(c, &clusterip_configs, list) {
121                 if (c->clusterip == clusterip)
122                         return c;
123         }
124 
125         return NULL;
126 }
127 
128 static inline struct clusterip_config *
129 clusterip_config_find_get(__be32 clusterip, int entry)
130 {
131         struct clusterip_config *c;
132 
133         rcu_read_lock_bh();
134         c = __clusterip_config_find(clusterip);
135         if (c) {
136                 if (unlikely(!atomic_inc_not_zero(&c->refcount)))
137                         c = NULL;
138                 else if (entry)
139                         atomic_inc(&c->entries);
140         }
141         rcu_read_unlock_bh();
142 
143         return c;
144 }
145 
146 static void
147 clusterip_config_init_nodelist(struct clusterip_config *c,
148                                const struct ipt_clusterip_tgt_info *i)
149 {
150         int n;
151 
152         for (n = 0; n < i->num_local_nodes; n++)
153                 set_bit(i->local_nodes[n] - 1, &c->local_nodes);
154 }
155 
156 static struct clusterip_config *
157 clusterip_config_init(const struct ipt_clusterip_tgt_info *i, __be32 ip,
158                         struct net_device *dev)
159 {
160         struct clusterip_config *c;
161 
162         c = kzalloc(sizeof(*c), GFP_ATOMIC);
163         if (!c)
164                 return NULL;
165 
166         c->dev = dev;
167         c->clusterip = ip;
168         memcpy(&c->clustermac, &i->clustermac, ETH_ALEN);
169         c->num_total_nodes = i->num_total_nodes;
170         clusterip_config_init_nodelist(c, i);
171         c->hash_mode = i->hash_mode;
172         c->hash_initval = i->hash_initval;
173         atomic_set(&c->refcount, 1);
174         atomic_set(&c->entries, 1);
175 
176 #ifdef CONFIG_PROC_FS
177         {
178                 char buffer[16];
179 
180                 /* create proc dir entry */
181                 sprintf(buffer, "%pI4", &ip);
182                 c->pde = proc_create_data(buffer, S_IWUSR|S_IRUSR,
183                                           clusterip_procdir,
184                                           &clusterip_proc_fops, c);
185                 if (!c->pde) {
186                         kfree(c);
187                         return NULL;
188                 }
189         }
190 #endif
191 
192         spin_lock_bh(&clusterip_lock);
193         list_add_rcu(&c->list, &clusterip_configs);
194         spin_unlock_bh(&clusterip_lock);
195 
196         return c;
197 }
198 
199 #ifdef CONFIG_PROC_FS
200 static int
201 clusterip_add_node(struct clusterip_config *c, u_int16_t nodenum)
202 {
203 
204         if (nodenum == 0 ||
205             nodenum > c->num_total_nodes)
206                 return 1;
207 
208         /* check if we already have this number in our bitfield */
209         if (test_and_set_bit(nodenum - 1, &c->local_nodes))
210                 return 1;
211 
212         return 0;
213 }
214 
215 static bool
216 clusterip_del_node(struct clusterip_config *c, u_int16_t nodenum)
217 {
218         if (nodenum == 0 ||
219             nodenum > c->num_total_nodes)
220                 return true;
221 
222         if (test_and_clear_bit(nodenum - 1, &c->local_nodes))
223                 return false;
224 
225         return true;
226 }
227 #endif
228 
229 static inline u_int32_t
230 clusterip_hashfn(const struct sk_buff *skb,
231                  const struct clusterip_config *config)
232 {
233         const struct iphdr *iph = ip_hdr(skb);
234         unsigned long hashval;
235         u_int16_t sport = 0, dport = 0;
236         int poff;
237 
238         poff = proto_ports_offset(iph->protocol);
239         if (poff >= 0) {
240                 const u_int16_t *ports;
241                 u16 _ports[2];
242 
243                 ports = skb_header_pointer(skb, iph->ihl * 4 + poff, 4, _ports);
244                 if (ports) {
245                         sport = ports[0];
246                         dport = ports[1];
247                 }
248         } else {
249                 if (net_ratelimit())
250                         pr_info("unknown protocol %u\n", iph->protocol);
251         }
252 
253         switch (config->hash_mode) {
254         case CLUSTERIP_HASHMODE_SIP:
255                 hashval = jhash_1word(ntohl(iph->saddr),
256                                       config->hash_initval);
257                 break;
258         case CLUSTERIP_HASHMODE_SIP_SPT:
259                 hashval = jhash_2words(ntohl(iph->saddr), sport,
260                                        config->hash_initval);
261                 break;
262         case CLUSTERIP_HASHMODE_SIP_SPT_DPT:
263                 hashval = jhash_3words(ntohl(iph->saddr), sport, dport,
264                                        config->hash_initval);
265                 break;
266         default:
267                 /* to make gcc happy */
268                 hashval = 0;
269                 /* This cannot happen, unless the check function wasn't called
270                  * at rule load time */
271                 pr_info("unknown mode %u\n", config->hash_mode);
272                 BUG();
273                 break;
274         }
275 
276         /* node numbers are 1..n, not 0..n */
277         return (((u64)hashval * config->num_total_nodes) >> 32) + 1;
278 }
279 
280 static inline int
281 clusterip_responsible(const struct clusterip_config *config, u_int32_t hash)
282 {
283         return test_bit(hash - 1, &config->local_nodes);
284 }
285 
286 /***********************************************************************
287  * IPTABLES TARGET
288  ***********************************************************************/
289 
290 static unsigned int
291 clusterip_tg(struct sk_buff *skb, const struct xt_action_param *par)
292 {
293         const struct ipt_clusterip_tgt_info *cipinfo = par->targinfo;
294         struct nf_conn *ct;
295         enum ip_conntrack_info ctinfo;
296         u_int32_t hash;
297 
298         /* don't need to clusterip_config_get() here, since refcount
299          * is only decremented by destroy() - and ip_tables guarantees
300          * that the ->target() function isn't called after ->destroy() */
301 
302         ct = nf_ct_get(skb, &ctinfo);
303         if (ct == NULL)
304                 return NF_DROP;
305 
306         /* special case: ICMP error handling. conntrack distinguishes between
307          * error messages (RELATED) and information requests (see below) */
308         if (ip_hdr(skb)->protocol == IPPROTO_ICMP &&
309             (ctinfo == IP_CT_RELATED ||
310              ctinfo == IP_CT_RELATED + IP_CT_IS_REPLY))
311                 return XT_CONTINUE;
312 
313         /* ip_conntrack_icmp guarantees us that we only have ICMP_ECHO,
314          * TIMESTAMP, INFO_REQUEST or ADDRESS type icmp packets from here
315          * on, which all have an ID field [relevant for hashing]. */
316 
317         hash = clusterip_hashfn(skb, cipinfo->config);
318 
319         switch (ctinfo) {
320                 case IP_CT_NEW:
321                         ct->mark = hash;
322                         break;
323                 case IP_CT_RELATED:
324                 case IP_CT_RELATED+IP_CT_IS_REPLY:
325                         /* FIXME: we don't handle expectations at the
326                          * moment.  they can arrive on a different node than
327                          * the master connection (e.g. FTP passive mode) */
328                 case IP_CT_ESTABLISHED:
329                 case IP_CT_ESTABLISHED+IP_CT_IS_REPLY:
330                         break;
331                 default:
332                         break;
333         }
334 
335 #ifdef DEBUG
336         nf_ct_dump_tuple_ip(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
337 #endif
338         pr_debug("hash=%u ct_hash=%u ", hash, ct->mark);
339         if (!clusterip_responsible(cipinfo->config, hash)) {
340                 pr_debug("not responsible\n");
341                 return NF_DROP;
342         }
343         pr_debug("responsible\n");
344 
345         /* despite being received via linklayer multicast, this is
346          * actually a unicast IP packet. TCP doesn't like PACKET_MULTICAST */
347         skb->pkt_type = PACKET_HOST;
348 
349         return XT_CONTINUE;
350 }
351 
352 static int clusterip_tg_check(const struct xt_tgchk_param *par)
353 {
354         struct ipt_clusterip_tgt_info *cipinfo = par->targinfo;
355         const struct ipt_entry *e = par->entryinfo;
356         struct clusterip_config *config;
357         int ret;
358 
359         if (cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP &&
360             cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP_SPT &&
361             cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP_SPT_DPT) {
362                 pr_info("unknown mode %u\n", cipinfo->hash_mode);
363                 return -EINVAL;
364 
365         }
366         if (e->ip.dmsk.s_addr != htonl(0xffffffff) ||
367             e->ip.dst.s_addr == 0) {
368                 pr_info("Please specify destination IP\n");
369                 return -EINVAL;
370         }
371 
372         /* FIXME: further sanity checks */
373 
374         config = clusterip_config_find_get(e->ip.dst.s_addr, 1);
375         if (!config) {
376                 if (!(cipinfo->flags & CLUSTERIP_FLAG_NEW)) {
377                         pr_info("no config found for %pI4, need 'new'\n",
378                                 &e->ip.dst.s_addr);
379                         return -EINVAL;
380                 } else {
381                         struct net_device *dev;
382 
383                         if (e->ip.iniface[0] == '\0') {
384                                 pr_info("Please specify an interface name\n");
385                                 return -EINVAL;
386                         }
387 
388                         dev = dev_get_by_name(&init_net, e->ip.iniface);
389                         if (!dev) {
390                                 pr_info("no such interface %s\n",
391                                         e->ip.iniface);
392                                 return -ENOENT;
393                         }
394 
395                         config = clusterip_config_init(cipinfo,
396                                                         e->ip.dst.s_addr, dev);
397                         if (!config) {
398                                 pr_info("cannot allocate config\n");
399                                 dev_put(dev);
400                                 return -ENOMEM;
401                         }
402                         dev_mc_add(config->dev, config->clustermac);
403                 }
404         }
405         cipinfo->config = config;
406 
407         ret = nf_ct_l3proto_try_module_get(par->family);
408         if (ret < 0)
409                 pr_info("cannot load conntrack support for proto=%u\n",
410                         par->family);
411         return ret;
412 }
413 
414 /* drop reference count of cluster config when rule is deleted */
415 static void clusterip_tg_destroy(const struct xt_tgdtor_param *par)
416 {
417         const struct ipt_clusterip_tgt_info *cipinfo = par->targinfo;
418 
419         /* if no more entries are referencing the config, remove it
420          * from the list and destroy the proc entry */
421         clusterip_config_entry_put(cipinfo->config);
422 
423         clusterip_config_put(cipinfo->config);
424 
425         nf_ct_l3proto_module_put(par->family);
426 }
427 
428 #ifdef CONFIG_COMPAT
429 struct compat_ipt_clusterip_tgt_info
430 {
431         u_int32_t       flags;
432         u_int8_t        clustermac[6];
433         u_int16_t       num_total_nodes;
434         u_int16_t       num_local_nodes;
435         u_int16_t       local_nodes[CLUSTERIP_MAX_NODES];
436         u_int32_t       hash_mode;
437         u_int32_t       hash_initval;
438         compat_uptr_t   config;
439 };
440 #endif /* CONFIG_COMPAT */
441 
442 static struct xt_target clusterip_tg_reg __read_mostly = {
443         .name           = "CLUSTERIP",
444         .family         = NFPROTO_IPV4,
445         .target         = clusterip_tg,
446         .checkentry     = clusterip_tg_check,
447         .destroy        = clusterip_tg_destroy,
448         .targetsize     = sizeof(struct ipt_clusterip_tgt_info),
449 #ifdef CONFIG_COMPAT
450         .compatsize     = sizeof(struct compat_ipt_clusterip_tgt_info),
451 #endif /* CONFIG_COMPAT */
452         .me             = THIS_MODULE
453 };
454 
455 
456 /***********************************************************************
457  * ARP MANGLING CODE
458  ***********************************************************************/
459 
460 /* hardcoded for 48bit ethernet and 32bit ipv4 addresses */
461 struct arp_payload {
462         u_int8_t src_hw[ETH_ALEN];
463         __be32 src_ip;
464         u_int8_t dst_hw[ETH_ALEN];
465         __be32 dst_ip;
466 } __packed;
467 
468 #ifdef DEBUG
469 static void arp_print(struct arp_payload *payload)
470 {
471 #define HBUFFERLEN 30
472         char hbuffer[HBUFFERLEN];
473         int j,k;
474 
475         for (k=0, j=0; k < HBUFFERLEN-3 && j < ETH_ALEN; j++) {
476                 hbuffer[k++] = hex_asc_hi(payload->src_hw[j]);
477                 hbuffer[k++] = hex_asc_lo(payload->src_hw[j]);
478                 hbuffer[k++]=':';
479         }
480         hbuffer[--k]='\0';
481 
482         pr_debug("src %pI4@%s, dst %pI4\n",
483                  &payload->src_ip, hbuffer, &payload->dst_ip);
484 }
485 #endif
486 
487 static unsigned int
488 arp_mangle(unsigned int hook,
489            struct sk_buff *skb,
490            const struct net_device *in,
491            const struct net_device *out,
492            int (*okfn)(struct sk_buff *))
493 {
494         struct arphdr *arp = arp_hdr(skb);
495         struct arp_payload *payload;
496         struct clusterip_config *c;
497 
498         /* we don't care about non-ethernet and non-ipv4 ARP */
499         if (arp->ar_hrd != htons(ARPHRD_ETHER) ||
500             arp->ar_pro != htons(ETH_P_IP) ||
501             arp->ar_pln != 4 || arp->ar_hln != ETH_ALEN)
502                 return NF_ACCEPT;
503 
504         /* we only want to mangle arp requests and replies */
505         if (arp->ar_op != htons(ARPOP_REPLY) &&
506             arp->ar_op != htons(ARPOP_REQUEST))
507                 return NF_ACCEPT;
508 
509         payload = (void *)(arp+1);
510 
511         /* if there is no clusterip configuration for the arp reply's
512          * source ip, we don't want to mangle it */
513         c = clusterip_config_find_get(payload->src_ip, 0);
514         if (!c)
515                 return NF_ACCEPT;
516 
517         /* normally the linux kernel always replies to arp queries of
518          * addresses on different interfacs.  However, in the CLUSTERIP case
519          * this wouldn't work, since we didn't subscribe the mcast group on
520          * other interfaces */
521         if (c->dev != out) {
522                 pr_debug("not mangling arp reply on different "
523                          "interface: cip'%s'-skb'%s'\n",
524                          c->dev->name, out->name);
525                 clusterip_config_put(c);
526                 return NF_ACCEPT;
527         }
528 
529         /* mangle reply hardware address */
530         memcpy(payload->src_hw, c->clustermac, arp->ar_hln);
531 
532 #ifdef DEBUG
533         pr_debug("mangled arp reply: ");
534         arp_print(payload);
535 #endif
536 
537         clusterip_config_put(c);
538 
539         return NF_ACCEPT;
540 }
541 
542 static struct nf_hook_ops cip_arp_ops __read_mostly = {
543         .hook = arp_mangle,
544         .pf = NFPROTO_ARP,
545         .hooknum = NF_ARP_OUT,
546         .priority = -1
547 };
548 
549 /***********************************************************************
550  * PROC DIR HANDLING
551  ***********************************************************************/
552 
553 #ifdef CONFIG_PROC_FS
554 
555 struct clusterip_seq_position {
556         unsigned int pos;       /* position */
557         unsigned int weight;    /* number of bits set == size */
558         unsigned int bit;       /* current bit */
559         unsigned long val;      /* current value */
560 };
561 
562 static void *clusterip_seq_start(struct seq_file *s, loff_t *pos)
563 {
564         struct clusterip_config *c = s->private;
565         unsigned int weight;
566         u_int32_t local_nodes;
567         struct clusterip_seq_position *idx;
568 
569         /* FIXME: possible race */
570         local_nodes = c->local_nodes;
571         weight = hweight32(local_nodes);
572         if (*pos >= weight)
573                 return NULL;
574 
575         idx = kmalloc(sizeof(struct clusterip_seq_position), GFP_KERNEL);
576         if (!idx)
577                 return ERR_PTR(-ENOMEM);
578 
579         idx->pos = *pos;
580         idx->weight = weight;
581         idx->bit = ffs(local_nodes);
582         idx->val = local_nodes;
583         clear_bit(idx->bit - 1, &idx->val);
584 
585         return idx;
586 }
587 
588 static void *clusterip_seq_next(struct seq_file *s, void *v, loff_t *pos)
589 {
590         struct clusterip_seq_position *idx = v;
591 
592         *pos = ++idx->pos;
593         if (*pos >= idx->weight) {
594                 kfree(v);
595                 return NULL;
596         }
597         idx->bit = ffs(idx->val);
598         clear_bit(idx->bit - 1, &idx->val);
599         return idx;
600 }
601 
602 static void clusterip_seq_stop(struct seq_file *s, void *v)
603 {
604         if (!IS_ERR(v))
605                 kfree(v);
606 }
607 
608 static int clusterip_seq_show(struct seq_file *s, void *v)
609 {
610         struct clusterip_seq_position *idx = v;
611 
612         if (idx->pos != 0)
613                 seq_putc(s, ',');
614 
615         seq_printf(s, "%u", idx->bit);
616 
617         if (idx->pos == idx->weight - 1)
618                 seq_putc(s, '\n');
619 
620         return 0;
621 }
622 
623 static const struct seq_operations clusterip_seq_ops = {
624         .start  = clusterip_seq_start,
625         .next   = clusterip_seq_next,
626         .stop   = clusterip_seq_stop,
627         .show   = clusterip_seq_show,
628 };
629 
630 static int clusterip_proc_open(struct inode *inode, struct file *file)
631 {
632         int ret = seq_open(file, &clusterip_seq_ops);
633 
634         if (!ret) {
635                 struct seq_file *sf = file->private_data;
636                 struct clusterip_config *c = PDE(inode)->data;
637 
638                 sf->private = c;
639 
640                 clusterip_config_get(c);
641         }
642 
643         return ret;
644 }
645 
646 static int clusterip_proc_release(struct inode *inode, struct file *file)
647 {
648         struct clusterip_config *c = PDE(inode)->data;
649         int ret;
650 
651         ret = seq_release(inode, file);
652 
653         if (!ret)
654                 clusterip_config_put(c);
655 
656         return ret;
657 }
658 
659 static ssize_t clusterip_proc_write(struct file *file, const char __user *input,
660                                 size_t size, loff_t *ofs)
661 {
662         struct clusterip_config *c = PDE(file->f_path.dentry->d_inode)->data;
663 #define PROC_WRITELEN   10
664         char buffer[PROC_WRITELEN+1];
665         unsigned long nodenum;
666 
667         if (size > PROC_WRITELEN)
668                 return -EIO;
669         if (copy_from_user(buffer, input, size))
670                 return -EFAULT;
671         buffer[size] = 0;
672 
673         if (*buffer == '+') {
674                 nodenum = simple_strtoul(buffer+1, NULL, 10);
675                 if (clusterip_add_node(c, nodenum))
676                         return -ENOMEM;
677         } else if (*buffer == '-') {
678                 nodenum = simple_strtoul(buffer+1, NULL,10);
679                 if (clusterip_del_node(c, nodenum))
680                         return -ENOENT;
681         } else
682                 return -EIO;
683 
684         return size;
685 }
686 
687 static const struct file_operations clusterip_proc_fops = {
688         .owner   = THIS_MODULE,
689         .open    = clusterip_proc_open,
690         .read    = seq_read,
691         .write   = clusterip_proc_write,
692         .llseek  = seq_lseek,
693         .release = clusterip_proc_release,
694 };
695 
696 #endif /* CONFIG_PROC_FS */
697 
698 static int __init clusterip_tg_init(void)
699 {
700         int ret;
701 
702         ret = xt_register_target(&clusterip_tg_reg);
703         if (ret < 0)
704                 return ret;
705 
706         ret = nf_register_hook(&cip_arp_ops);
707         if (ret < 0)
708                 goto cleanup_target;
709 
710 #ifdef CONFIG_PROC_FS
711         clusterip_procdir = proc_mkdir("ipt_CLUSTERIP", init_net.proc_net);
712         if (!clusterip_procdir) {
713                 pr_err("Unable to proc dir entry\n");
714                 ret = -ENOMEM;
715                 goto cleanup_hook;
716         }
717 #endif /* CONFIG_PROC_FS */
718 
719         pr_info("ClusterIP Version %s loaded successfully\n",
720                 CLUSTERIP_VERSION);
721         return 0;
722 
723 #ifdef CONFIG_PROC_FS
724 cleanup_hook:
725         nf_unregister_hook(&cip_arp_ops);
726 #endif /* CONFIG_PROC_FS */
727 cleanup_target:
728         xt_unregister_target(&clusterip_tg_reg);
729         return ret;
730 }
731 
732 static void __exit clusterip_tg_exit(void)
733 {
734         pr_info("ClusterIP Version %s unloading\n", CLUSTERIP_VERSION);
735 #ifdef CONFIG_PROC_FS
736         remove_proc_entry(clusterip_procdir->name, clusterip_procdir->parent);
737 #endif
738         nf_unregister_hook(&cip_arp_ops);
739         xt_unregister_target(&clusterip_tg_reg);
740 
741         /* Wait for completion of call_rcu_bh()'s (clusterip_config_rcu_free) */
742         rcu_barrier_bh();
743 }
744 
745 module_init(clusterip_tg_init);
746 module_exit(clusterip_tg_exit);
747 

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