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>
5 * Development of this code funded by SuSE Linux AG, http://www.suse.com/
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.
12 #include <linux/module.h>
13 #include <linux/proc_fs.h>
14 #include <linux/jhash.h>
15 #include <linux/bitops.h>
16 #include <linux/skbuff.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 #include <linux/netfilter_arp.h>
25 #include <linux/netfilter/x_tables.h>
26 #include <linux/netfilter_ipv4/ip_tables.h>
27 #include <linux/netfilter_ipv4/ipt_CLUSTERIP.h>
28 #include <net/netfilter/nf_conntrack.h>
29 #include <net/checksum.h>
31 #define CLUSTERIP_VERSION "0.8"
33 #define DEBUG_CLUSTERIP
35 #ifdef DEBUG_CLUSTERIP
41 MODULE_LICENSE("GPL");
42 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
43 MODULE_DESCRIPTION("iptables target for CLUSTERIP");
45 struct clusterip_config {
46 struct list_head list; /* list of all configs */
47 atomic_t refcount; /* reference count */
48 atomic_t entries; /* number of entries/rules
51 __be32 clusterip; /* the IP address */
52 u_int8_t clustermac[ETH_ALEN]; /* the MAC address */
53 struct net_device *dev; /* device */
54 u_int16_t num_total_nodes; /* total number of nodes */
55 unsigned long local_nodes; /* node number array */
58 struct proc_dir_entry *pde; /* proc dir entry */
60 enum clusterip_hashmode hash_mode; /* which hashing mode */
61 u_int32_t hash_initval; /* hash initialization */
64 static LIST_HEAD(clusterip_configs);
66 /* clusterip_lock protects the clusterip_configs list */
67 static DEFINE_RWLOCK(clusterip_lock);
70 static const struct file_operations clusterip_proc_fops;
71 static struct proc_dir_entry *clusterip_procdir;
75 clusterip_config_get(struct clusterip_config *c)
77 atomic_inc(&c->refcount);
81 clusterip_config_put(struct clusterip_config *c)
83 if (atomic_dec_and_test(&c->refcount))
87 /* increase the count of entries(rules) using/referencing this config */
89 clusterip_config_entry_get(struct clusterip_config *c)
91 atomic_inc(&c->entries);
94 /* decrease the count of entries using/referencing this config. If last
95 * entry(rule) is removed, remove the config from lists, but don't free it
96 * yet, since proc-files could still be holding references */
98 clusterip_config_entry_put(struct clusterip_config *c)
100 if (atomic_dec_and_test(&c->entries)) {
101 write_lock_bh(&clusterip_lock);
103 write_unlock_bh(&clusterip_lock);
105 dev_mc_delete(c->dev, c->clustermac, ETH_ALEN, 0);
108 /* In case anyone still accesses the file, the open/close
109 * functions are also incrementing the refcount on their own,
110 * so it's safe to remove the entry even if it's in use. */
111 #ifdef CONFIG_PROC_FS
112 remove_proc_entry(c->pde->name, c->pde->parent);
117 static struct clusterip_config *
118 __clusterip_config_find(__be32 clusterip)
120 struct list_head *pos;
122 list_for_each(pos, &clusterip_configs) {
123 struct clusterip_config *c = list_entry(pos,
124 struct clusterip_config, list);
125 if (c->clusterip == clusterip) {
133 static inline struct clusterip_config *
134 clusterip_config_find_get(__be32 clusterip, int entry)
136 struct clusterip_config *c;
138 read_lock_bh(&clusterip_lock);
139 c = __clusterip_config_find(clusterip);
141 read_unlock_bh(&clusterip_lock);
144 atomic_inc(&c->refcount);
146 atomic_inc(&c->entries);
147 read_unlock_bh(&clusterip_lock);
153 clusterip_config_init_nodelist(struct clusterip_config *c,
154 const struct ipt_clusterip_tgt_info *i)
158 for (n = 0; n < i->num_local_nodes; n++) {
159 set_bit(i->local_nodes[n] - 1, &c->local_nodes);
163 static struct clusterip_config *
164 clusterip_config_init(struct ipt_clusterip_tgt_info *i, __be32 ip,
165 struct net_device *dev)
167 struct clusterip_config *c;
169 c = kzalloc(sizeof(*c), GFP_ATOMIC);
175 memcpy(&c->clustermac, &i->clustermac, ETH_ALEN);
176 c->num_total_nodes = i->num_total_nodes;
177 clusterip_config_init_nodelist(c, i);
178 c->hash_mode = i->hash_mode;
179 c->hash_initval = i->hash_initval;
180 atomic_set(&c->refcount, 1);
181 atomic_set(&c->entries, 1);
183 #ifdef CONFIG_PROC_FS
187 /* create proc dir entry */
188 sprintf(buffer, "%u.%u.%u.%u", NIPQUAD(ip));
189 c->pde = create_proc_entry(buffer, S_IWUSR|S_IRUSR,
196 c->pde->proc_fops = &clusterip_proc_fops;
200 write_lock_bh(&clusterip_lock);
201 list_add(&c->list, &clusterip_configs);
202 write_unlock_bh(&clusterip_lock);
207 #ifdef CONFIG_PROC_FS
209 clusterip_add_node(struct clusterip_config *c, u_int16_t nodenum)
213 nodenum > c->num_total_nodes)
216 /* check if we already have this number in our bitfield */
217 if (test_and_set_bit(nodenum - 1, &c->local_nodes))
224 clusterip_del_node(struct clusterip_config *c, u_int16_t nodenum)
227 nodenum > c->num_total_nodes)
230 if (test_and_clear_bit(nodenum - 1, &c->local_nodes))
237 static inline u_int32_t
238 clusterip_hashfn(const struct sk_buff *skb,
239 const struct clusterip_config *config)
241 const struct iphdr *iph = ip_hdr(skb);
242 unsigned long hashval;
243 u_int16_t sport, dport;
244 const u_int16_t *ports;
246 switch (iph->protocol) {
249 case IPPROTO_UDPLITE:
253 ports = (const void *)iph+iph->ihl*4;
258 if (net_ratelimit()) {
259 printk(KERN_NOTICE "CLUSTERIP: unknown protocol `%u'\n",
265 switch (config->hash_mode) {
266 case CLUSTERIP_HASHMODE_SIP:
267 hashval = jhash_1word(ntohl(iph->saddr),
268 config->hash_initval);
270 case CLUSTERIP_HASHMODE_SIP_SPT:
271 hashval = jhash_2words(ntohl(iph->saddr), sport,
272 config->hash_initval);
274 case CLUSTERIP_HASHMODE_SIP_SPT_DPT:
275 hashval = jhash_3words(ntohl(iph->saddr), sport, dport,
276 config->hash_initval);
279 /* to make gcc happy */
281 /* This cannot happen, unless the check function wasn't called
282 * at rule load time */
283 printk("CLUSTERIP: unknown mode `%u'\n", config->hash_mode);
288 /* node numbers are 1..n, not 0..n */
289 return ((hashval % config->num_total_nodes)+1);
293 clusterip_responsible(const struct clusterip_config *config, u_int32_t hash)
295 return test_bit(hash - 1, &config->local_nodes);
298 /***********************************************************************
300 ***********************************************************************/
303 target(struct sk_buff **pskb,
304 const struct net_device *in,
305 const struct net_device *out,
306 unsigned int hooknum,
307 const struct xt_target *target,
308 const void *targinfo)
310 const struct ipt_clusterip_tgt_info *cipinfo = targinfo;
312 enum ip_conntrack_info ctinfo;
315 /* don't need to clusterip_config_get() here, since refcount
316 * is only decremented by destroy() - and ip_tables guarantees
317 * that the ->target() function isn't called after ->destroy() */
319 ct = nf_ct_get(*pskb, &ctinfo);
321 printk(KERN_ERR "CLUSTERIP: no conntrack!\n");
322 /* FIXME: need to drop invalid ones, since replies
323 * to outgoing connections of other nodes will be
324 * marked as INVALID */
328 /* special case: ICMP error handling. conntrack distinguishes between
329 * error messages (RELATED) and information requests (see below) */
330 if (ip_hdr(*pskb)->protocol == IPPROTO_ICMP
331 && (ctinfo == IP_CT_RELATED
332 || ctinfo == IP_CT_RELATED+IP_CT_IS_REPLY))
335 /* ip_conntrack_icmp guarantees us that we only have ICMP_ECHO,
336 * TIMESTAMP, INFO_REQUEST or ADDRESS type icmp packets from here
337 * on, which all have an ID field [relevant for hashing]. */
339 hash = clusterip_hashfn(*pskb, cipinfo->config);
346 case IP_CT_RELATED+IP_CT_IS_REPLY:
347 /* FIXME: we don't handle expectations at the
348 * moment. they can arrive on a different node than
349 * the master connection (e.g. FTP passive mode) */
350 case IP_CT_ESTABLISHED:
351 case IP_CT_ESTABLISHED+IP_CT_IS_REPLY:
357 #ifdef DEBUG_CLUSTERP
358 DUMP_TUPLE(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
360 DEBUGP("hash=%u ct_hash=%u ", hash, ct->mark);
361 if (!clusterip_responsible(cipinfo->config, hash)) {
362 DEBUGP("not responsible\n");
365 DEBUGP("responsible\n");
367 /* despite being received via linklayer multicast, this is
368 * actually a unicast IP packet. TCP doesn't like PACKET_MULTICAST */
369 (*pskb)->pkt_type = PACKET_HOST;
375 checkentry(const char *tablename,
377 const struct xt_target *target,
379 unsigned int hook_mask)
381 struct ipt_clusterip_tgt_info *cipinfo = targinfo;
382 const struct ipt_entry *e = e_void;
384 struct clusterip_config *config;
386 if (cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP &&
387 cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP_SPT &&
388 cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP_SPT_DPT) {
389 printk(KERN_WARNING "CLUSTERIP: unknown mode `%u'\n",
394 if (e->ip.dmsk.s_addr != htonl(0xffffffff)
395 || e->ip.dst.s_addr == 0) {
396 printk(KERN_ERR "CLUSTERIP: Please specify destination IP\n");
400 /* FIXME: further sanity checks */
402 config = clusterip_config_find_get(e->ip.dst.s_addr, 1);
404 if (cipinfo->config != NULL) {
405 /* Case A: This is an entry that gets reloaded, since
406 * it still has a cipinfo->config pointer. Simply
407 * increase the entry refcount and return */
408 if (cipinfo->config != config) {
409 printk(KERN_ERR "CLUSTERIP: Reloaded entry "
410 "has invalid config pointer!\n");
414 /* Case B: This is a new rule referring to an existing
415 * clusterip config. */
416 cipinfo->config = config;
419 /* Case C: This is a completely new clusterip config */
420 if (!(cipinfo->flags & CLUSTERIP_FLAG_NEW)) {
421 printk(KERN_WARNING "CLUSTERIP: no config found for %u.%u.%u.%u, need 'new'\n", NIPQUAD(e->ip.dst.s_addr));
424 struct net_device *dev;
426 if (e->ip.iniface[0] == '\0') {
427 printk(KERN_WARNING "CLUSTERIP: Please specify an interface name\n");
431 dev = dev_get_by_name(e->ip.iniface);
433 printk(KERN_WARNING "CLUSTERIP: no such interface %s\n", e->ip.iniface);
437 config = clusterip_config_init(cipinfo,
438 e->ip.dst.s_addr, dev);
440 printk(KERN_WARNING "CLUSTERIP: cannot allocate config\n");
444 dev_mc_add(config->dev,config->clustermac, ETH_ALEN, 0);
446 cipinfo->config = config;
449 if (nf_ct_l3proto_try_module_get(target->family) < 0) {
450 printk(KERN_WARNING "can't load conntrack support for "
451 "proto=%d\n", target->family);
458 /* drop reference count of cluster config when rule is deleted */
459 static void destroy(const struct xt_target *target, void *targinfo)
461 struct ipt_clusterip_tgt_info *cipinfo = targinfo;
463 /* if no more entries are referencing the config, remove it
464 * from the list and destroy the proc entry */
465 clusterip_config_entry_put(cipinfo->config);
467 clusterip_config_put(cipinfo->config);
469 nf_ct_l3proto_module_put(target->family);
472 static struct xt_target clusterip_tgt = {
476 .targetsize = sizeof(struct ipt_clusterip_tgt_info),
477 .checkentry = checkentry,
483 /***********************************************************************
485 ***********************************************************************/
487 /* hardcoded for 48bit ethernet and 32bit ipv4 addresses */
489 u_int8_t src_hw[ETH_ALEN];
491 u_int8_t dst_hw[ETH_ALEN];
493 } __attribute__ ((packed));
495 #ifdef CLUSTERIP_DEBUG
496 static void arp_print(struct arp_payload *payload)
498 #define HBUFFERLEN 30
499 char hbuffer[HBUFFERLEN];
501 const char hexbuf[]= "0123456789abcdef";
503 for (k=0, j=0; k < HBUFFERLEN-3 && j < ETH_ALEN; j++) {
504 hbuffer[k++]=hexbuf[(payload->src_hw[j]>>4)&15];
505 hbuffer[k++]=hexbuf[payload->src_hw[j]&15];
510 printk("src %u.%u.%u.%u@%s, dst %u.%u.%u.%u\n",
511 NIPQUAD(payload->src_ip), hbuffer,
512 NIPQUAD(payload->dst_ip));
517 arp_mangle(unsigned int hook,
518 struct sk_buff **pskb,
519 const struct net_device *in,
520 const struct net_device *out,
521 int (*okfn)(struct sk_buff *))
523 struct arphdr *arp = arp_hdr(*pskb);
524 struct arp_payload *payload;
525 struct clusterip_config *c;
527 /* we don't care about non-ethernet and non-ipv4 ARP */
528 if (arp->ar_hrd != htons(ARPHRD_ETHER)
529 || arp->ar_pro != htons(ETH_P_IP)
530 || arp->ar_pln != 4 || arp->ar_hln != ETH_ALEN)
533 /* we only want to mangle arp requests and replies */
534 if (arp->ar_op != htons(ARPOP_REPLY)
535 && arp->ar_op != htons(ARPOP_REQUEST))
538 payload = (void *)(arp+1);
540 /* if there is no clusterip configuration for the arp reply's
541 * source ip, we don't want to mangle it */
542 c = clusterip_config_find_get(payload->src_ip, 0);
546 /* normally the linux kernel always replies to arp queries of
547 * addresses on different interfacs. However, in the CLUSTERIP case
548 * this wouldn't work, since we didn't subscribe the mcast group on
549 * other interfaces */
551 DEBUGP("CLUSTERIP: not mangling arp reply on different "
552 "interface: cip'%s'-skb'%s'\n", c->dev->name, out->name);
553 clusterip_config_put(c);
557 /* mangle reply hardware address */
558 memcpy(payload->src_hw, c->clustermac, arp->ar_hln);
560 #ifdef CLUSTERIP_DEBUG
561 DEBUGP(KERN_DEBUG "CLUSTERIP mangled arp reply: ");
565 clusterip_config_put(c);
570 static struct nf_hook_ops cip_arp_ops = {
573 .hooknum = NF_ARP_OUT,
577 /***********************************************************************
579 ***********************************************************************/
581 #ifdef CONFIG_PROC_FS
583 struct clusterip_seq_position {
584 unsigned int pos; /* position */
585 unsigned int weight; /* number of bits set == size */
586 unsigned int bit; /* current bit */
587 unsigned long val; /* current value */
590 static void *clusterip_seq_start(struct seq_file *s, loff_t *pos)
592 struct proc_dir_entry *pde = s->private;
593 struct clusterip_config *c = pde->data;
595 u_int32_t local_nodes;
596 struct clusterip_seq_position *idx;
598 /* FIXME: possible race */
599 local_nodes = c->local_nodes;
600 weight = hweight32(local_nodes);
604 idx = kmalloc(sizeof(struct clusterip_seq_position), GFP_KERNEL);
606 return ERR_PTR(-ENOMEM);
609 idx->weight = weight;
610 idx->bit = ffs(local_nodes);
611 idx->val = local_nodes;
612 clear_bit(idx->bit - 1, &idx->val);
617 static void *clusterip_seq_next(struct seq_file *s, void *v, loff_t *pos)
619 struct clusterip_seq_position *idx = (struct clusterip_seq_position *)v;
622 if (*pos >= idx->weight) {
626 idx->bit = ffs(idx->val);
627 clear_bit(idx->bit - 1, &idx->val);
631 static void clusterip_seq_stop(struct seq_file *s, void *v)
636 static int clusterip_seq_show(struct seq_file *s, void *v)
638 struct clusterip_seq_position *idx = (struct clusterip_seq_position *)v;
643 seq_printf(s, "%u", idx->bit);
645 if (idx->pos == idx->weight - 1)
651 static struct seq_operations clusterip_seq_ops = {
652 .start = clusterip_seq_start,
653 .next = clusterip_seq_next,
654 .stop = clusterip_seq_stop,
655 .show = clusterip_seq_show,
658 static int clusterip_proc_open(struct inode *inode, struct file *file)
660 int ret = seq_open(file, &clusterip_seq_ops);
663 struct seq_file *sf = file->private_data;
664 struct proc_dir_entry *pde = PDE(inode);
665 struct clusterip_config *c = pde->data;
669 clusterip_config_get(c);
675 static int clusterip_proc_release(struct inode *inode, struct file *file)
677 struct proc_dir_entry *pde = PDE(inode);
678 struct clusterip_config *c = pde->data;
681 ret = seq_release(inode, file);
684 clusterip_config_put(c);
689 static ssize_t clusterip_proc_write(struct file *file, const char __user *input,
690 size_t size, loff_t *ofs)
692 #define PROC_WRITELEN 10
693 char buffer[PROC_WRITELEN+1];
694 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
695 struct clusterip_config *c = pde->data;
696 unsigned long nodenum;
698 if (copy_from_user(buffer, input, PROC_WRITELEN))
701 if (*buffer == '+') {
702 nodenum = simple_strtoul(buffer+1, NULL, 10);
703 if (clusterip_add_node(c, nodenum))
705 } else if (*buffer == '-') {
706 nodenum = simple_strtoul(buffer+1, NULL,10);
707 if (clusterip_del_node(c, nodenum))
715 static const struct file_operations clusterip_proc_fops = {
716 .owner = THIS_MODULE,
717 .open = clusterip_proc_open,
719 .write = clusterip_proc_write,
721 .release = clusterip_proc_release,
724 #endif /* CONFIG_PROC_FS */
726 static int __init ipt_clusterip_init(void)
730 ret = xt_register_target(&clusterip_tgt);
734 ret = nf_register_hook(&cip_arp_ops);
738 #ifdef CONFIG_PROC_FS
739 clusterip_procdir = proc_mkdir("ipt_CLUSTERIP", proc_net);
740 if (!clusterip_procdir) {
741 printk(KERN_ERR "CLUSTERIP: Unable to proc dir entry\n");
745 #endif /* CONFIG_PROC_FS */
747 printk(KERN_NOTICE "ClusterIP Version %s loaded successfully\n",
751 #ifdef CONFIG_PROC_FS
753 nf_unregister_hook(&cip_arp_ops);
754 #endif /* CONFIG_PROC_FS */
756 xt_unregister_target(&clusterip_tgt);
760 static void __exit ipt_clusterip_fini(void)
762 printk(KERN_NOTICE "ClusterIP Version %s unloading\n",
764 #ifdef CONFIG_PROC_FS
765 remove_proc_entry(clusterip_procdir->name, clusterip_procdir->parent);
767 nf_unregister_hook(&cip_arp_ops);
768 xt_unregister_target(&clusterip_tgt);
771 module_init(ipt_clusterip_init);
772 module_exit(ipt_clusterip_fini);