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 #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>
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>
33 #define CLUSTERIP_VERSION "0.8"
35 MODULE_LICENSE("GPL");
36 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
37 MODULE_DESCRIPTION("Xtables: CLUSTERIP target");
39 struct clusterip_config {
40 struct list_head list; /* list of all configs */
41 atomic_t refcount; /* reference count */
42 atomic_t entries; /* number of entries/rules
45 __be32 clusterip; /* the IP address */
46 u_int8_t clustermac[ETH_ALEN]; /* the MAC address */
47 struct net_device *dev; /* device */
48 u_int16_t num_total_nodes; /* total number of nodes */
49 unsigned long local_nodes; /* node number array */
52 struct proc_dir_entry *pde; /* proc dir entry */
54 enum clusterip_hashmode hash_mode; /* which hashing mode */
55 u_int32_t hash_initval; /* hash initialization */
59 static LIST_HEAD(clusterip_configs);
61 /* clusterip_lock protects the clusterip_configs list */
62 static DEFINE_SPINLOCK(clusterip_lock);
65 static const struct file_operations clusterip_proc_fops;
66 static struct proc_dir_entry *clusterip_procdir;
70 clusterip_config_get(struct clusterip_config *c)
72 atomic_inc(&c->refcount);
76 static void clusterip_config_rcu_free(struct rcu_head *head)
78 kfree(container_of(head, struct clusterip_config, rcu));
82 clusterip_config_put(struct clusterip_config *c)
84 if (atomic_dec_and_test(&c->refcount))
85 call_rcu_bh(&c->rcu, clusterip_config_rcu_free);
88 /* decrease the count of entries using/referencing this config. If last
89 * entry(rule) is removed, remove the config from lists, but don't free it
90 * yet, since proc-files could still be holding references */
92 clusterip_config_entry_put(struct clusterip_config *c)
95 if (atomic_dec_and_lock(&c->entries, &clusterip_lock)) {
96 list_del_rcu(&c->list);
97 spin_unlock(&clusterip_lock);
100 dev_mc_del(c->dev, c->clustermac);
103 /* In case anyone still accesses the file, the open/close
104 * functions are also incrementing the refcount on their own,
105 * so it's safe to remove the entry even if it's in use. */
106 #ifdef CONFIG_PROC_FS
107 remove_proc_entry(c->pde->name, c->pde->parent);
114 static struct clusterip_config *
115 __clusterip_config_find(__be32 clusterip)
117 struct clusterip_config *c;
119 list_for_each_entry_rcu(c, &clusterip_configs, list) {
120 if (c->clusterip == clusterip)
127 static inline struct clusterip_config *
128 clusterip_config_find_get(__be32 clusterip, int entry)
130 struct clusterip_config *c;
133 c = __clusterip_config_find(clusterip);
135 if (unlikely(!atomic_inc_not_zero(&c->refcount)))
138 atomic_inc(&c->entries);
140 rcu_read_unlock_bh();
146 clusterip_config_init_nodelist(struct clusterip_config *c,
147 const struct ipt_clusterip_tgt_info *i)
151 for (n = 0; n < i->num_local_nodes; n++)
152 set_bit(i->local_nodes[n] - 1, &c->local_nodes);
155 static struct clusterip_config *
156 clusterip_config_init(const struct ipt_clusterip_tgt_info *i, __be32 ip,
157 struct net_device *dev)
159 struct clusterip_config *c;
161 c = kzalloc(sizeof(*c), GFP_ATOMIC);
167 memcpy(&c->clustermac, &i->clustermac, ETH_ALEN);
168 c->num_total_nodes = i->num_total_nodes;
169 clusterip_config_init_nodelist(c, i);
170 c->hash_mode = i->hash_mode;
171 c->hash_initval = i->hash_initval;
172 atomic_set(&c->refcount, 1);
173 atomic_set(&c->entries, 1);
175 #ifdef CONFIG_PROC_FS
179 /* create proc dir entry */
180 sprintf(buffer, "%pI4", &ip);
181 c->pde = proc_create_data(buffer, S_IWUSR|S_IRUSR,
183 &clusterip_proc_fops, c);
191 spin_lock_bh(&clusterip_lock);
192 list_add_rcu(&c->list, &clusterip_configs);
193 spin_unlock_bh(&clusterip_lock);
198 #ifdef CONFIG_PROC_FS
200 clusterip_add_node(struct clusterip_config *c, u_int16_t nodenum)
204 nodenum > c->num_total_nodes)
207 /* check if we already have this number in our bitfield */
208 if (test_and_set_bit(nodenum - 1, &c->local_nodes))
215 clusterip_del_node(struct clusterip_config *c, u_int16_t nodenum)
218 nodenum > c->num_total_nodes)
221 if (test_and_clear_bit(nodenum - 1, &c->local_nodes))
228 static inline u_int32_t
229 clusterip_hashfn(const struct sk_buff *skb,
230 const struct clusterip_config *config)
232 const struct iphdr *iph = ip_hdr(skb);
233 unsigned long hashval;
234 u_int16_t sport, dport;
235 const u_int16_t *ports;
237 switch (iph->protocol) {
240 case IPPROTO_UDPLITE:
244 ports = (const void *)iph+iph->ihl*4;
250 pr_info("unknown protocol %u\n", iph->protocol);
254 switch (config->hash_mode) {
255 case CLUSTERIP_HASHMODE_SIP:
256 hashval = jhash_1word(ntohl(iph->saddr),
257 config->hash_initval);
259 case CLUSTERIP_HASHMODE_SIP_SPT:
260 hashval = jhash_2words(ntohl(iph->saddr), sport,
261 config->hash_initval);
263 case CLUSTERIP_HASHMODE_SIP_SPT_DPT:
264 hashval = jhash_3words(ntohl(iph->saddr), sport, dport,
265 config->hash_initval);
268 /* to make gcc happy */
270 /* This cannot happen, unless the check function wasn't called
271 * at rule load time */
272 pr_info("unknown mode %u\n", config->hash_mode);
277 /* node numbers are 1..n, not 0..n */
278 return (((u64)hashval * config->num_total_nodes) >> 32) + 1;
282 clusterip_responsible(const struct clusterip_config *config, u_int32_t hash)
284 return test_bit(hash - 1, &config->local_nodes);
287 /***********************************************************************
289 ***********************************************************************/
292 clusterip_tg(struct sk_buff *skb, const struct xt_action_param *par)
294 const struct ipt_clusterip_tgt_info *cipinfo = par->targinfo;
296 enum ip_conntrack_info ctinfo;
299 /* don't need to clusterip_config_get() here, since refcount
300 * is only decremented by destroy() - and ip_tables guarantees
301 * that the ->target() function isn't called after ->destroy() */
303 ct = nf_ct_get(skb, &ctinfo);
305 pr_info("no conntrack!\n");
306 /* FIXME: need to drop invalid ones, since replies
307 * to outgoing connections of other nodes will be
308 * marked as INVALID */
312 /* special case: ICMP error handling. conntrack distinguishes between
313 * error messages (RELATED) and information requests (see below) */
314 if (ip_hdr(skb)->protocol == IPPROTO_ICMP &&
315 (ctinfo == IP_CT_RELATED ||
316 ctinfo == IP_CT_RELATED + IP_CT_IS_REPLY))
319 /* ip_conntrack_icmp guarantees us that we only have ICMP_ECHO,
320 * TIMESTAMP, INFO_REQUEST or ADDRESS type icmp packets from here
321 * on, which all have an ID field [relevant for hashing]. */
323 hash = clusterip_hashfn(skb, cipinfo->config);
330 case IP_CT_RELATED+IP_CT_IS_REPLY:
331 /* FIXME: we don't handle expectations at the
332 * moment. they can arrive on a different node than
333 * the master connection (e.g. FTP passive mode) */
334 case IP_CT_ESTABLISHED:
335 case IP_CT_ESTABLISHED+IP_CT_IS_REPLY:
342 nf_ct_dump_tuple_ip(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
344 pr_debug("hash=%u ct_hash=%u ", hash, ct->mark);
345 if (!clusterip_responsible(cipinfo->config, hash)) {
346 pr_debug("not responsible\n");
349 pr_debug("responsible\n");
351 /* despite being received via linklayer multicast, this is
352 * actually a unicast IP packet. TCP doesn't like PACKET_MULTICAST */
353 skb->pkt_type = PACKET_HOST;
358 static int clusterip_tg_check(const struct xt_tgchk_param *par)
360 struct ipt_clusterip_tgt_info *cipinfo = par->targinfo;
361 const struct ipt_entry *e = par->entryinfo;
362 struct clusterip_config *config;
365 if (cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP &&
366 cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP_SPT &&
367 cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP_SPT_DPT) {
368 pr_info("unknown mode %u\n", cipinfo->hash_mode);
372 if (e->ip.dmsk.s_addr != htonl(0xffffffff) ||
373 e->ip.dst.s_addr == 0) {
374 pr_info("Please specify destination IP\n");
378 /* FIXME: further sanity checks */
380 config = clusterip_config_find_get(e->ip.dst.s_addr, 1);
382 if (!(cipinfo->flags & CLUSTERIP_FLAG_NEW)) {
383 pr_info("no config found for %pI4, need 'new'\n",
387 struct net_device *dev;
389 if (e->ip.iniface[0] == '\0') {
390 pr_info("Please specify an interface name\n");
394 dev = dev_get_by_name(&init_net, e->ip.iniface);
396 pr_info("no such interface %s\n",
401 config = clusterip_config_init(cipinfo,
402 e->ip.dst.s_addr, dev);
404 pr_info("cannot allocate config\n");
408 dev_mc_add(config->dev, config->clustermac);
411 cipinfo->config = config;
413 ret = nf_ct_l3proto_try_module_get(par->family);
415 pr_info("cannot load conntrack support for proto=%u\n",
420 /* drop reference count of cluster config when rule is deleted */
421 static void clusterip_tg_destroy(const struct xt_tgdtor_param *par)
423 const struct ipt_clusterip_tgt_info *cipinfo = par->targinfo;
425 /* if no more entries are referencing the config, remove it
426 * from the list and destroy the proc entry */
427 clusterip_config_entry_put(cipinfo->config);
429 clusterip_config_put(cipinfo->config);
431 nf_ct_l3proto_module_put(par->family);
435 struct compat_ipt_clusterip_tgt_info
438 u_int8_t clustermac[6];
439 u_int16_t num_total_nodes;
440 u_int16_t num_local_nodes;
441 u_int16_t local_nodes[CLUSTERIP_MAX_NODES];
443 u_int32_t hash_initval;
444 compat_uptr_t config;
446 #endif /* CONFIG_COMPAT */
448 static struct xt_target clusterip_tg_reg __read_mostly = {
450 .family = NFPROTO_IPV4,
451 .target = clusterip_tg,
452 .checkentry = clusterip_tg_check,
453 .destroy = clusterip_tg_destroy,
454 .targetsize = sizeof(struct ipt_clusterip_tgt_info),
456 .compatsize = sizeof(struct compat_ipt_clusterip_tgt_info),
457 #endif /* CONFIG_COMPAT */
462 /***********************************************************************
464 ***********************************************************************/
466 /* hardcoded for 48bit ethernet and 32bit ipv4 addresses */
468 u_int8_t src_hw[ETH_ALEN];
470 u_int8_t dst_hw[ETH_ALEN];
475 static void arp_print(struct arp_payload *payload)
477 #define HBUFFERLEN 30
478 char hbuffer[HBUFFERLEN];
481 for (k=0, j=0; k < HBUFFERLEN-3 && j < ETH_ALEN; j++) {
482 hbuffer[k++] = hex_asc_hi(payload->src_hw[j]);
483 hbuffer[k++] = hex_asc_lo(payload->src_hw[j]);
488 pr_debug("src %pI4@%s, dst %pI4\n",
489 &payload->src_ip, hbuffer, &payload->dst_ip);
494 arp_mangle(unsigned int hook,
496 const struct net_device *in,
497 const struct net_device *out,
498 int (*okfn)(struct sk_buff *))
500 struct arphdr *arp = arp_hdr(skb);
501 struct arp_payload *payload;
502 struct clusterip_config *c;
504 /* we don't care about non-ethernet and non-ipv4 ARP */
505 if (arp->ar_hrd != htons(ARPHRD_ETHER) ||
506 arp->ar_pro != htons(ETH_P_IP) ||
507 arp->ar_pln != 4 || arp->ar_hln != ETH_ALEN)
510 /* we only want to mangle arp requests and replies */
511 if (arp->ar_op != htons(ARPOP_REPLY) &&
512 arp->ar_op != htons(ARPOP_REQUEST))
515 payload = (void *)(arp+1);
517 /* if there is no clusterip configuration for the arp reply's
518 * source ip, we don't want to mangle it */
519 c = clusterip_config_find_get(payload->src_ip, 0);
523 /* normally the linux kernel always replies to arp queries of
524 * addresses on different interfacs. However, in the CLUSTERIP case
525 * this wouldn't work, since we didn't subscribe the mcast group on
526 * other interfaces */
528 pr_debug("not mangling arp reply on different "
529 "interface: cip'%s'-skb'%s'\n",
530 c->dev->name, out->name);
531 clusterip_config_put(c);
535 /* mangle reply hardware address */
536 memcpy(payload->src_hw, c->clustermac, arp->ar_hln);
539 pr_debug("mangled arp reply: ");
543 clusterip_config_put(c);
548 static struct nf_hook_ops cip_arp_ops __read_mostly = {
551 .hooknum = NF_ARP_OUT,
555 /***********************************************************************
557 ***********************************************************************/
559 #ifdef CONFIG_PROC_FS
561 struct clusterip_seq_position {
562 unsigned int pos; /* position */
563 unsigned int weight; /* number of bits set == size */
564 unsigned int bit; /* current bit */
565 unsigned long val; /* current value */
568 static void *clusterip_seq_start(struct seq_file *s, loff_t *pos)
570 struct clusterip_config *c = s->private;
572 u_int32_t local_nodes;
573 struct clusterip_seq_position *idx;
575 /* FIXME: possible race */
576 local_nodes = c->local_nodes;
577 weight = hweight32(local_nodes);
581 idx = kmalloc(sizeof(struct clusterip_seq_position), GFP_KERNEL);
583 return ERR_PTR(-ENOMEM);
586 idx->weight = weight;
587 idx->bit = ffs(local_nodes);
588 idx->val = local_nodes;
589 clear_bit(idx->bit - 1, &idx->val);
594 static void *clusterip_seq_next(struct seq_file *s, void *v, loff_t *pos)
596 struct clusterip_seq_position *idx = v;
599 if (*pos >= idx->weight) {
603 idx->bit = ffs(idx->val);
604 clear_bit(idx->bit - 1, &idx->val);
608 static void clusterip_seq_stop(struct seq_file *s, void *v)
614 static int clusterip_seq_show(struct seq_file *s, void *v)
616 struct clusterip_seq_position *idx = v;
621 seq_printf(s, "%u", idx->bit);
623 if (idx->pos == idx->weight - 1)
629 static const struct seq_operations clusterip_seq_ops = {
630 .start = clusterip_seq_start,
631 .next = clusterip_seq_next,
632 .stop = clusterip_seq_stop,
633 .show = clusterip_seq_show,
636 static int clusterip_proc_open(struct inode *inode, struct file *file)
638 int ret = seq_open(file, &clusterip_seq_ops);
641 struct seq_file *sf = file->private_data;
642 struct clusterip_config *c = PDE(inode)->data;
646 clusterip_config_get(c);
652 static int clusterip_proc_release(struct inode *inode, struct file *file)
654 struct clusterip_config *c = PDE(inode)->data;
657 ret = seq_release(inode, file);
660 clusterip_config_put(c);
665 static ssize_t clusterip_proc_write(struct file *file, const char __user *input,
666 size_t size, loff_t *ofs)
668 struct clusterip_config *c = PDE(file->f_path.dentry->d_inode)->data;
669 #define PROC_WRITELEN 10
670 char buffer[PROC_WRITELEN+1];
671 unsigned long nodenum;
673 if (copy_from_user(buffer, input, PROC_WRITELEN))
676 if (*buffer == '+') {
677 nodenum = simple_strtoul(buffer+1, NULL, 10);
678 if (clusterip_add_node(c, nodenum))
680 } else if (*buffer == '-') {
681 nodenum = simple_strtoul(buffer+1, NULL,10);
682 if (clusterip_del_node(c, nodenum))
690 static const struct file_operations clusterip_proc_fops = {
691 .owner = THIS_MODULE,
692 .open = clusterip_proc_open,
694 .write = clusterip_proc_write,
696 .release = clusterip_proc_release,
699 #endif /* CONFIG_PROC_FS */
701 static int __init clusterip_tg_init(void)
705 ret = xt_register_target(&clusterip_tg_reg);
709 ret = nf_register_hook(&cip_arp_ops);
713 #ifdef CONFIG_PROC_FS
714 clusterip_procdir = proc_mkdir("ipt_CLUSTERIP", init_net.proc_net);
715 if (!clusterip_procdir) {
716 pr_err("Unable to proc dir entry\n");
720 #endif /* CONFIG_PROC_FS */
722 pr_info("ClusterIP Version %s loaded successfully\n",
726 #ifdef CONFIG_PROC_FS
728 nf_unregister_hook(&cip_arp_ops);
729 #endif /* CONFIG_PROC_FS */
731 xt_unregister_target(&clusterip_tg_reg);
735 static void __exit clusterip_tg_exit(void)
737 pr_info("ClusterIP Version %s unloading\n", CLUSTERIP_VERSION);
738 #ifdef CONFIG_PROC_FS
739 remove_proc_entry(clusterip_procdir->name, clusterip_procdir->parent);
741 nf_unregister_hook(&cip_arp_ops);
742 xt_unregister_target(&clusterip_tg_reg);
744 /* Wait for completion of call_rcu_bh()'s (clusterip_config_rcu_free) */
748 module_init(clusterip_tg_init);
749 module_exit(clusterip_tg_exit);