net/ipv4/netfilter/ipt_CLUSTERIP.c

   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 #include <linux/module.h>
  13 #include <linux/config.h>
  14 #include <linux/proc_fs.h>
  15 #include <linux/jhash.h>
  16 #include <linux/skbuff.h>
  17 #include <linux/ip.h>
  18 #include <linux/tcp.h>
  19 #include <linux/udp.h>
  20 #include <linux/icmp.h>
  21 #include <linux/if_arp.h>
  22 #include <linux/proc_fs.h>
  23 #include <linux/seq_file.h>
  24
  25 #include <net/checksum.h>
  26
  27 #include <linux/netfilter_arp.h>
  28
  29 #include <linux/netfilter_ipv4/ip_tables.h>
  30 #include <linux/netfilter_ipv4/ipt_CLUSTERIP.h>
  31 #include <linux/netfilter_ipv4/ip_conntrack.h>
  32 #include <linux/netfilter_ipv4/lockhelp.h>
  33
  34 #define CLUSTERIP_VERSION "0.6"
  35
  36 #define DEBUG_CLUSTERIP
  37
  38 #ifdef DEBUG_CLUSTERIP
  39 #define DEBUGP  printk
  40 #else
  41 #define DEBUGP
  42 #endif
  43
  44 MODULE_LICENSE("GPL");
  45 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
  46 MODULE_DESCRIPTION("iptables target for CLUSTERIP");
  47
  48 struct clusterip_config {
  49         struct list_head list;                  /* list of all configs */
  50         atomic_t refcount;                      /* reference count */
  51
  52         u_int32_t clusterip;                    /* the IP address */
  53         u_int8_t clustermac[ETH_ALEN];          /* the MAC address */
  54         struct net_device *dev;                 /* device */
  55         u_int16_t num_total_nodes;              /* total number of nodes */
  56         u_int16_t num_local_nodes;              /* number of local nodes */
  57         u_int16_t local_nodes[CLUSTERIP_MAX_NODES];     /* node number array */
  58
  59 #ifdef CONFIG_PROC_FS
  60         struct proc_dir_entry *pde;             /* proc dir entry */
  61 #endif
  62         enum clusterip_hashmode hash_mode;      /* which hashing mode */
  63         u_int32_t hash_initval;                 /* hash initialization */
  64 };
  65
  66 static LIST_HEAD(clusterip_configs);
  67
  68 /* clusterip_lock protects the clusterip_configs list _AND_ the configurable
  69  * data within all structurses (num_local_nodes, local_nodes[]) */
  70 static DECLARE_RWLOCK(clusterip_lock);
  71
  72 #ifdef CONFIG_PROC_FS
  73 static struct file_operations clusterip_proc_fops;
  74 static struct proc_dir_entry *clusterip_procdir;
  75 #endif
  76
  77 static inline void
  78 clusterip_config_get(struct clusterip_config *c) {
  79         atomic_inc(&c->refcount);
  80 }
  81
  82 static inline void
  83 clusterip_config_put(struct clusterip_config *c) {
  84         if (atomic_dec_and_test(&c->refcount)) {
  85                 WRITE_LOCK(&clusterip_lock);
  86                 list_del(&c->list);
  87                 WRITE_UNLOCK(&clusterip_lock);
  88                 dev_mc_delete(c->dev, c->clustermac, ETH_ALEN, 0);
  89                 dev_put(c->dev);
  90                 kfree(c);
  91         }
  92 }
  93
  94
  95 static struct clusterip_config *
  96 __clusterip_config_find(u_int32_t clusterip)
  97 {
  98         struct list_head *pos;
  99
 100         MUST_BE_READ_LOCKED(&clusterip_lock);
 101         list_for_each(pos, &clusterip_configs) {
 102                 struct clusterip_config *c = list_entry(pos,
 103                                         struct clusterip_config, list);
 104                 if (c->clusterip == clusterip) {
 105                         return c;
 106                 }
 107         }
 108
 109         return NULL;
 110 }
 111
 112 static inline struct clusterip_config *
 113 clusterip_config_find_get(u_int32_t clusterip)
 114 {
 115         struct clusterip_config *c;
 116
 117         READ_LOCK(&clusterip_lock);
 118         c = __clusterip_config_find(clusterip);
 119         if (!c) {
 120                 READ_UNLOCK(&clusterip_lock);
 121                 return NULL;
 122         }
 123         atomic_inc(&c->refcount);
 124         READ_UNLOCK(&clusterip_lock);
 125
 126         return c;
 127 }
 128
 129 static struct clusterip_config *
 130 clusterip_config_init(struct ipt_clusterip_tgt_info *i, u_int32_t ip,
 131                         struct net_device *dev)
 132 {
 133         struct clusterip_config *c;
 134         char buffer[16];
 135
 136         c = kmalloc(sizeof(*c), GFP_ATOMIC);
 137         if (!c)
 138                 return NULL;
 139
 140         memset(c, 0, sizeof(*c));
 141         c->dev = dev;
 142         c->clusterip = ip;
 143         memcpy(&c->clustermac, &i->clustermac, ETH_ALEN);
 144         c->num_total_nodes = i->num_total_nodes;
 145         c->num_local_nodes = i->num_local_nodes;
 146         memcpy(&c->local_nodes, &i->local_nodes, sizeof(&c->local_nodes));
 147         c->hash_mode = i->hash_mode;
 148         c->hash_initval = i->hash_initval;
 149         atomic_set(&c->refcount, 1);
 150
 151 #ifdef CONFIG_PROC_FS
 152         /* create proc dir entry */
 153         sprintf(buffer, "%u.%u.%u.%u", NIPQUAD(ip));
 154         c->pde = create_proc_entry(buffer, S_IWUSR|S_IRUSR, clusterip_procdir);
 155         if (!c->pde) {
 156                 kfree(c);
 157                 return NULL;
 158         }
 159         c->pde->proc_fops = &clusterip_proc_fops;
 160         c->pde->data = c;
 161 #endif
 162
 163         WRITE_LOCK(&clusterip_lock);
 164         list_add(&c->list, &clusterip_configs);
 165         WRITE_UNLOCK(&clusterip_lock);
 166
 167         return c;
 168 }
 169
 170 static int
 171 clusterip_add_node(struct clusterip_config *c, u_int16_t nodenum)
 172 {
 173         int i;
 174
 175         WRITE_LOCK(&clusterip_lock);
 176
 177         if (c->num_local_nodes >= CLUSTERIP_MAX_NODES
 178             || nodenum > CLUSTERIP_MAX_NODES) {
 179                 WRITE_UNLOCK(&clusterip_lock);
 180                 return 1;
 181         }
 182
 183         /* check if we alrady have this number in our array */
 184         for (i = 0; i < c->num_local_nodes; i++) {
 185                 if (c->local_nodes[i] == nodenum) {
 186                         WRITE_UNLOCK(&clusterip_lock);
 187                         return 1;
 188                 }
 189         }
 190
 191         c->local_nodes[c->num_local_nodes++] = nodenum;
 192
 193         WRITE_UNLOCK(&clusterip_lock);
 194         return 0;
 195 }
 196
 197 static int
 198 clusterip_del_node(struct clusterip_config *c, u_int16_t nodenum)
 199 {
 200         int i;
 201
 202         WRITE_LOCK(&clusterip_lock);
 203
 204         if (c->num_local_nodes <= 1 || nodenum > CLUSTERIP_MAX_NODES) {
 205                 WRITE_UNLOCK(&clusterip_lock);
 206                 return 1;
 207         }
 208
 209         for (i = 0; i < c->num_local_nodes; i++) {
 210                 if (c->local_nodes[i] == nodenum) {
 211                         int size = sizeof(u_int16_t)*(c->num_local_nodes-(i+1));
 212                         memmove(&c->local_nodes[i], &c->local_nodes[i+1], size);
 213                         c->num_local_nodes--;
 214                         WRITE_UNLOCK(&clusterip_lock);
 215                         return 0;
 216                 }
 217         }
 218
 219         WRITE_UNLOCK(&clusterip_lock);
 220         return 1;
 221 }
 222
 223 static inline u_int32_t
 224 clusterip_hashfn(struct sk_buff *skb, struct clusterip_config *config)
 225 {
 226         struct iphdr *iph = skb->nh.iph;
 227         unsigned long hashval;
 228         u_int16_t sport, dport;
 229         struct tcphdr *th;
 230         struct udphdr *uh;
 231         struct icmphdr *ih;
 232
 233         switch (iph->protocol) {
 234         case IPPROTO_TCP:
 235                 th = (void *)iph+iph->ihl*4;
 236                 sport = ntohs(th->source);
 237                 dport = ntohs(th->dest);
 238                 break;
 239         case IPPROTO_UDP:
 240                 uh = (void *)iph+iph->ihl*4;
 241                 sport = ntohs(uh->source);
 242                 dport = ntohs(uh->dest);
 243                 break;
 244         case IPPROTO_ICMP:
 245                 ih = (void *)iph+iph->ihl*4;
 246                 sport = ntohs(ih->un.echo.id);
 247                 dport = (ih->type<<8)|ih->code;
 248                 break;
 249         default:
 250                 if (net_ratelimit()) {
 251                         printk(KERN_NOTICE "CLUSTERIP: unknown protocol `%u'\n",
 252                                 iph->protocol);
 253                 }
 254                 sport = dport = 0;
 255         }
 256
 257         switch (config->hash_mode) {
 258         case CLUSTERIP_HASHMODE_SIP:
 259                 hashval = jhash_1word(ntohl(iph->saddr),
 260                                       config->hash_initval);
 261                 break;
 262         case CLUSTERIP_HASHMODE_SIP_SPT:
 263                 hashval = jhash_2words(ntohl(iph->saddr), sport,
 264                                        config->hash_initval);
 265                 break;
 266         case CLUSTERIP_HASHMODE_SIP_SPT_DPT:
 267                 hashval = jhash_3words(ntohl(iph->saddr), sport, dport,
 268                                        config->hash_initval);
 269                 break;
 270         default:
 271                 /* to make gcc happy */
 272                 hashval = 0;
 273                 /* This cannot happen, unless the check function wasn't called
 274                  * at rule load time */
 275                 printk("CLUSTERIP: unknown mode `%u'\n", config->hash_mode);
 276                 BUG();
 277                 break;
 278         }
 279
 280         /* node numbers are 1..n, not 0..n */
 281         return ((hashval % config->num_total_nodes)+1);
 282 }
 283
 284 static inline int
 285 clusterip_responsible(struct clusterip_config *config, u_int32_t hash)
 286 {
 287         int i;
 288
 289         READ_LOCK(&clusterip_lock);
 290
 291         if (config->num_local_nodes == 0) {
 292                 READ_UNLOCK(&clusterip_lock);
 293                 return 0;
 294         }
 295
 296         for (i = 0; i < config->num_local_nodes; i++) {
 297                 if (config->local_nodes[i] == hash) {
 298                         READ_UNLOCK(&clusterip_lock);
 299                         return 1;
 300                 }
 301         }
 302
 303         READ_UNLOCK(&clusterip_lock);
 304
 305         return 0;
 306 }
 307
 308 /***********************************************************************
 309  * IPTABLES TARGET
 310  ***********************************************************************/
 311
 312 static unsigned int
 313 target(struct sk_buff **pskb,
 314        const struct net_device *in,
 315        const struct net_device *out,
 316        unsigned int hooknum,
 317        const void *targinfo,
 318        void *userinfo)
 319 {
 320         const struct ipt_clusterip_tgt_info *cipinfo = targinfo;
 321         enum ip_conntrack_info ctinfo;
 322         struct ip_conntrack *ct = ip_conntrack_get((*pskb), &ctinfo);
 323         u_int32_t hash;
 324
 325         /* don't need to clusterip_config_get() here, since refcount
 326          * is only decremented by destroy() - and ip_tables guarantees
 327          * that the ->target() function isn't called after ->destroy() */
 328
 329         if (!ct) {
 330                 printk(KERN_ERR "CLUSTERIP: no conntrack!\n");
 331                         /* FIXME: need to drop invalid ones, since replies
 332                          * to outgoing connections of other nodes will be
 333                          * marked as INVALID */
 334                 return NF_DROP;
 335         }
 336
 337         /* special case: ICMP error handling. conntrack distinguishes between
 338          * error messages (RELATED) and information requests (see below) */
 339         if ((*pskb)->nh.iph->protocol == IPPROTO_ICMP
 340             && (ctinfo == IP_CT_RELATED
 341                 || ctinfo == IP_CT_IS_REPLY+IP_CT_IS_REPLY))
 342                 return IPT_CONTINUE;
 343
 344         /* ip_conntrack_icmp guarantees us that we only have ICMP_ECHO,
 345          * TIMESTAMP, INFO_REQUEST or ADDRESS type icmp packets from here
 346          * on, which all have an ID field [relevant for hashing]. */
 347
 348         hash = clusterip_hashfn(*pskb, cipinfo->config);
 349
 350         switch (ctinfo) {
 351                 case IP_CT_NEW:
 352                         ct->mark = hash;
 353                         break;
 354                 case IP_CT_RELATED:
 355                 case IP_CT_RELATED+IP_CT_IS_REPLY:
 356                         /* FIXME: we don't handle expectations at the
 357                          * moment.  they can arrive on a different node than
 358                          * the master connection (e.g. FTP passive mode) */
 359                 case IP_CT_ESTABLISHED:
 360                 case IP_CT_ESTABLISHED+IP_CT_IS_REPLY:
 361                         break;
 362                 default:
 363                         break;
 364         }
 365
 366 #ifdef DEBUG_CLUSTERP
 367         DUMP_TUPLE(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 368 #endif
 369         DEBUGP("hash=%u ct_hash=%lu ", hash, ct->mark);
 370         if (!clusterip_responsible(cipinfo->config, hash)) {
 371                 DEBUGP("not responsible\n");
 372                 return NF_DROP;
 373         }
 374         DEBUGP("responsible\n");
 375
 376         /* despite being received via linklayer multicast, this is
 377          * actually a unicast IP packet. TCP doesn't like PACKET_MULTICAST */
 378         (*pskb)->pkt_type = PACKET_HOST;
 379
 380         return IPT_CONTINUE;
 381 }
 382
 383 static int
 384 checkentry(const char *tablename,
 385            const struct ipt_entry *e,
 386            void *targinfo,
 387            unsigned int targinfosize,
 388            unsigned int hook_mask)
 389 {
 390         struct ipt_clusterip_tgt_info *cipinfo = targinfo;
 391
 392         struct clusterip_config *config;
 393
 394         if (targinfosize != IPT_ALIGN(sizeof(struct ipt_clusterip_tgt_info))) {
 395                 printk(KERN_WARNING "CLUSTERIP: targinfosize %u != %Zu\n",
 396                        targinfosize,
 397                        IPT_ALIGN(sizeof(struct ipt_clusterip_tgt_info)));
 398                 return 0;
 399         }
 400
 401         if (cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP &&
 402             cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP_SPT &&
 403             cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP_SPT_DPT) {
 404                 printk(KERN_WARNING "CLUSTERIP: unknown mode `%u'\n",
 405                         cipinfo->hash_mode);
 406                 return 0;
 407
 408         }
 409         if (e->ip.dmsk.s_addr != 0xffffffff
 410             || e->ip.dst.s_addr == 0) {
 411                 printk(KERN_ERR "CLUSTERIP: Please specify destination IP\n");
 412                 return 0;
 413         }
 414
 415         /* FIXME: further sanity checks */
 416
 417         config = clusterip_config_find_get(e->ip.dst.s_addr);
 418         if (!config) {
 419                 if (!(cipinfo->flags & CLUSTERIP_FLAG_NEW)) {
 420                         printk(KERN_WARNING "CLUSTERIP: no config found for %u.%u.%u.%u, need 'new'\n", NIPQUAD(e->ip.dst.s_addr));
 421                         return 0;
 422                 } else {
 423                         struct net_device *dev;
 424
 425                         if (e->ip.iniface[0] == '\0') {
 426                                 printk(KERN_WARNING "CLUSTERIP: Please specify an interface name\n");
 427                                 return 0;
 428                         }
 429
 430                         dev = dev_get_by_name(e->ip.iniface);
 431                         if (!dev) {
 432                                 printk(KERN_WARNING "CLUSTERIP: no such interface %s\n", e->ip.iniface);
 433                                 return 0;
 434                         }
 435
 436                         config = clusterip_config_init(cipinfo,
 437                                                         e->ip.dst.s_addr, dev);
 438                         if (!config) {
 439                                 printk(KERN_WARNING "CLUSTERIP: cannot allocate config\n");
 440                                 dev_put(dev);
 441                                 return 0;
 442                         }
 443                         dev_mc_add(config->dev,config->clustermac, ETH_ALEN, 0);
 444                 }
 445         }
 446
 447         cipinfo->config = config;
 448
 449         return 1;
 450 }
 451
 452 /* drop reference count of cluster config when rule is deleted */
 453 static void destroy(void *matchinfo, unsigned int matchinfosize)
 454 {
 455         struct ipt_clusterip_tgt_info *cipinfo = matchinfo;
 456
 457         /* we first remove the proc entry and then drop the reference
 458          * count.  In case anyone still accesses the file, the open/close
 459          * functions are also incrementing the refcount on their own */
 460 #ifdef CONFIG_PROC_FS
 461         remove_proc_entry(cipinfo->config->pde->name,
 462                           cipinfo->config->pde->parent);
 463 #endif
 464         clusterip_config_put(cipinfo->config);
 465 }
 466
 467 static struct ipt_target clusterip_tgt = {
 468         .name = "CLUSTERIP",
 469         .target = &target,
 470         .checkentry = &checkentry,
 471         .destroy = &destroy,
 472         .me = THIS_MODULE
 473 };
 474
 475
 476 /***********************************************************************
 477  * ARP MANGLING CODE
 478  ***********************************************************************/
 479
 480 /* hardcoded for 48bit ethernet and 32bit ipv4 addresses */
 481 struct arp_payload {
 482         u_int8_t src_hw[ETH_ALEN];
 483         u_int32_t src_ip;
 484         u_int8_t dst_hw[ETH_ALEN];
 485         u_int32_t dst_ip;
 486 } __attribute__ ((packed));
 487
 488 #ifdef CLUSTERIP_DEBUG
 489 static void arp_print(struct arp_payload *payload)
 490 {
 491 #define HBUFFERLEN 30
 492         char hbuffer[HBUFFERLEN];
 493         int j,k;
 494         const char hexbuf[]= "0123456789abcdef";
 495
 496         for (k=0, j=0; k < HBUFFERLEN-3 && j < ETH_ALEN; j++) {
 497                 hbuffer[k++]=hexbuf[(payload->src_hw[j]>>4)&15];
 498                 hbuffer[k++]=hexbuf[payload->src_hw[j]&15];
 499                 hbuffer[k++]=':';
 500         }
 501         hbuffer[--k]='\0';
 502
 503         printk("src %u.%u.%u.%u@%s, dst %u.%u.%u.%u\n",
 504                 NIPQUAD(payload->src_ip), hbuffer,
 505                 NIPQUAD(payload->dst_ip));
 506 }
 507 #endif
 508
 509 static unsigned int
 510 arp_mangle(unsigned int hook,
 511            struct sk_buff **pskb,
 512            const struct net_device *in,
 513            const struct net_device *out,
 514            int (*okfn)(struct sk_buff *))
 515 {
 516         struct arphdr *arp = (*pskb)->nh.arph;
 517         struct arp_payload *payload;
 518         struct clusterip_config *c;
 519
 520         /* we don't care about non-ethernet and non-ipv4 ARP */
 521         if (arp->ar_hrd != htons(ARPHRD_ETHER)
 522             || arp->ar_pro != htons(ETH_P_IP)
 523             || arp->ar_pln != 4 || arp->ar_hln != ETH_ALEN)
 524                 return NF_ACCEPT;
 525
 526         /* we only want to mangle arp replies */
 527         if (arp->ar_op != htons(ARPOP_REPLY))
 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(payload->src_ip);
 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 != out) {
 543                 DEBUGP("CLUSTERIP: not mangling arp reply on different "
 544                        "interface: cip'%s'-skb'%s'\n", c->dev->name, out->name);
 545                 clusterip_config_put(c);
 546                 return NF_ACCEPT;
 547         }
 548
 549         /* mangle reply hardware address */
 550         memcpy(payload->src_hw, c->clustermac, arp->ar_hln);
 551
 552 #ifdef CLUSTERIP_DEBUG
 553         DEBUGP(KERN_DEBUG "CLUSTERIP mangled arp reply: ");
 554         arp_print(payload);
 555 #endif
 556
 557         clusterip_config_put(c);
 558
 559         return NF_ACCEPT;
 560 }
 561
 562 static struct nf_hook_ops cip_arp_ops = {
 563         .hook = arp_mangle,
 564         .pf = NF_ARP,
 565         .hooknum = NF_ARP_OUT,
 566         .priority = -1
 567 };
 568
 569 /***********************************************************************
 570  * PROC DIR HANDLING
 571  ***********************************************************************/
 572
 573 #ifdef CONFIG_PROC_FS
 574
 575 static void *clusterip_seq_start(struct seq_file *s, loff_t *pos)
 576 {
 577         struct proc_dir_entry *pde = s->private;
 578         struct clusterip_config *c = pde->data;
 579         unsigned int *nodeidx;
 580
 581         READ_LOCK(&clusterip_lock);
 582         if (*pos >= c->num_local_nodes)
 583                 return NULL;
 584
 585         nodeidx = kmalloc(sizeof(unsigned int), GFP_KERNEL);
 586         if (!nodeidx)
 587                 return ERR_PTR(-ENOMEM);
 588
 589         *nodeidx = *pos;
 590         return nodeidx;
 591 }
 592
 593 static void *clusterip_seq_next(struct seq_file *s, void *v, loff_t *pos)
 594 {
 595         struct proc_dir_entry *pde = s->private;
 596         struct clusterip_config *c = pde->data;
 597         unsigned int *nodeidx = (unsigned int *)v;
 598
 599         *pos = ++(*nodeidx);
 600         if (*pos >= c->num_local_nodes) {
 601                 kfree(v);
 602                 return NULL;
 603         }
 604         return nodeidx;
 605 }
 606
 607 static void clusterip_seq_stop(struct seq_file *s, void *v)
 608 {
 609         kfree(v);
 610
 611         READ_UNLOCK(&clusterip_lock);
 612 }
 613
 614 static int clusterip_seq_show(struct seq_file *s, void *v)
 615 {
 616         struct proc_dir_entry *pde = s->private;
 617         struct clusterip_config *c = pde->data;
 618         unsigned int *nodeidx = (unsigned int *)v;
 619
 620         if (*nodeidx != 0)
 621                 seq_putc(s, ',');
 622         seq_printf(s, "%u", c->local_nodes[*nodeidx]);
 623
 624         if (*nodeidx == c->num_local_nodes-1)
 625                 seq_putc(s, '\n');
 626
 627         return 0;
 628 }
 629
 630 static struct seq_operations clusterip_seq_ops = {
 631         .start  = clusterip_seq_start,
 632         .next   = clusterip_seq_next,
 633         .stop   = clusterip_seq_stop,
 634         .show   = clusterip_seq_show,
 635 };
 636
 637 static int clusterip_proc_open(struct inode *inode, struct file *file)
 638 {
 639         int ret = seq_open(file, &clusterip_seq_ops);
 640
 641         if (!ret) {
 642                 struct seq_file *sf = file->private_data;
 643                 struct proc_dir_entry *pde = PDE(inode);
 644                 struct clusterip_config *c = pde->data;
 645
 646                 sf->private = pde;
 647
 648                 clusterip_config_get(c);
 649         }
 650
 651         return ret;
 652 }
 653
 654 static int clusterip_proc_release(struct inode *inode, struct file *file)
 655 {
 656         struct proc_dir_entry *pde = PDE(inode);
 657         struct clusterip_config *c = pde->data;
 658         int ret;
 659
 660         ret = seq_release(inode, file);
 661
 662         if (!ret)
 663                 clusterip_config_put(c);
 664
 665         return ret;
 666 }
 667
 668 static ssize_t clusterip_proc_write(struct file *file, const char __user *input,
 669                                 size_t size, loff_t *ofs)
 670 {
 671 #define PROC_WRITELEN   10
 672         char buffer[PROC_WRITELEN+1];
 673         struct proc_dir_entry *pde = PDE(file->f_dentry->d_inode);
 674         struct clusterip_config *c = pde->data;
 675         unsigned long nodenum;
 676
 677         if (copy_from_user(buffer, input, PROC_WRITELEN))
 678                 return -EFAULT;
 679
 680         if (*buffer == '+') {
 681                 nodenum = simple_strtoul(buffer+1, NULL, 10);
 682                 if (clusterip_add_node(c, nodenum))
 683                         return -ENOMEM;
 684         } else if (*buffer == '-') {
 685                 nodenum = simple_strtoul(buffer+1, NULL,10);
 686                 if (clusterip_del_node(c, nodenum))
 687                         return -ENOENT;
 688         } else
 689                 return -EIO;
 690
 691         return size;
 692 }
 693
 694 static struct file_operations clusterip_proc_fops = {
 695         .owner   = THIS_MODULE,
 696         .open    = clusterip_proc_open,
 697         .read    = seq_read,
 698         .write   = clusterip_proc_write,
 699         .llseek  = seq_lseek,
 700         .release = clusterip_proc_release,
 701 };
 702
 703 #endif /* CONFIG_PROC_FS */
 704
 705 static int init_or_cleanup(int fini)
 706 {
 707         int ret;
 708
 709         if (fini)
 710                 goto cleanup;
 711
 712         if (ipt_register_target(&clusterip_tgt)) {
 713                 ret = -EINVAL;
 714                 goto cleanup_none;
 715         }
 716
 717         if (nf_register_hook(&cip_arp_ops) < 0) {
 718                 ret = -EINVAL;
 719                 goto cleanup_target;
 720         }
 721
 722 #ifdef CONFIG_PROC_FS
 723         clusterip_procdir = proc_mkdir("ipt_CLUSTERIP", proc_net);
 724         if (!clusterip_procdir) {
 725                 printk(KERN_ERR "CLUSTERIP: Unable to proc dir entry\n");
 726                 ret = -ENOMEM;
 727                 goto cleanup_hook;
 728         }
 729 #endif /* CONFIG_PROC_FS */
 730
 731         printk(KERN_NOTICE "ClusterIP Version %s loaded successfully\n",
 732                 CLUSTERIP_VERSION);
 733
 734         return 0;
 735
 736 cleanup:
 737         printk(KERN_NOTICE "ClusterIP Version %s unloading\n",
 738                 CLUSTERIP_VERSION);
 739 #ifdef CONFIG_PROC_FS
 740         remove_proc_entry(clusterip_procdir->name, clusterip_procdir->parent);
 741 #endif
 742 cleanup_hook:
 743         nf_unregister_hook(&cip_arp_ops);
 744 cleanup_target:
 745         ipt_unregister_target(&clusterip_tgt);
 746 cleanup_none:
 747         return -EINVAL;
 748 }
 749
 750 static int __init init(void)
 751 {
 752         return init_or_cleanup(0);
 753 }
 754
 755 static void __exit fini(void)
 756 {
 757         init_or_cleanup(1);
 758 }
 759
 760 module_init(init);
 761 module_exit(fini);