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/seq_file.h>
23 #include <linux/netfilter_arp.h>
24 #include <linux/netfilter/x_tables.h>
25 #include <linux/netfilter_ipv4/ip_tables.h>
26 #include <linux/netfilter_ipv4/ipt_CLUSTERIP.h>
27 #include <net/netfilter/nf_conntrack.h>
28 #include <net/net_namespace.h>
29 #include <net/checksum.h>
31 #define CLUSTERIP_VERSION "0.8"
33 MODULE_LICENSE("GPL");
34 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
35 MODULE_DESCRIPTION("Xtables: CLUSTERIP target");
37 struct clusterip_config {
38 struct list_head list; /* list of all configs */
39 atomic_t refcount; /* reference count */
40 atomic_t entries; /* number of entries/rules
43 __be32 clusterip; /* the IP address */
44 u_int8_t clustermac[ETH_ALEN]; /* the MAC address */
45 struct net_device *dev; /* device */
46 u_int16_t num_total_nodes; /* total number of nodes */
47 unsigned long local_nodes; /* node number array */
50 struct proc_dir_entry *pde; /* proc dir entry */
52 enum clusterip_hashmode hash_mode; /* which hashing mode */
53 u_int32_t hash_initval; /* hash initialization */
56 static LIST_HEAD(clusterip_configs);
58 /* clusterip_lock protects the clusterip_configs list */
59 static DEFINE_RWLOCK(clusterip_lock);
62 static const struct file_operations clusterip_proc_fops;
63 static struct proc_dir_entry *clusterip_procdir;
67 clusterip_config_get(struct clusterip_config *c)
69 atomic_inc(&c->refcount);
73 clusterip_config_put(struct clusterip_config *c)
75 if (atomic_dec_and_test(&c->refcount))
79 /* decrease the count of entries using/referencing this config. If last
80 * entry(rule) is removed, remove the config from lists, but don't free it
81 * yet, since proc-files could still be holding references */
83 clusterip_config_entry_put(struct clusterip_config *c)
85 if (atomic_dec_and_test(&c->entries)) {
86 write_lock_bh(&clusterip_lock);
88 write_unlock_bh(&clusterip_lock);
90 dev_mc_delete(c->dev, c->clustermac, ETH_ALEN, 0);
93 /* In case anyone still accesses the file, the open/close
94 * functions are also incrementing the refcount on their own,
95 * so it's safe to remove the entry even if it's in use. */
97 remove_proc_entry(c->pde->name, c->pde->parent);
102 static struct clusterip_config *
103 __clusterip_config_find(__be32 clusterip)
105 struct clusterip_config *c;
107 list_for_each_entry(c, &clusterip_configs, list) {
108 if (c->clusterip == clusterip)
115 static inline struct clusterip_config *
116 clusterip_config_find_get(__be32 clusterip, int entry)
118 struct clusterip_config *c;
120 read_lock_bh(&clusterip_lock);
121 c = __clusterip_config_find(clusterip);
123 read_unlock_bh(&clusterip_lock);
126 atomic_inc(&c->refcount);
128 atomic_inc(&c->entries);
129 read_unlock_bh(&clusterip_lock);
135 clusterip_config_init_nodelist(struct clusterip_config *c,
136 const struct ipt_clusterip_tgt_info *i)
140 for (n = 0; n < i->num_local_nodes; n++)
141 set_bit(i->local_nodes[n] - 1, &c->local_nodes);
144 static struct clusterip_config *
145 clusterip_config_init(const struct ipt_clusterip_tgt_info *i, __be32 ip,
146 struct net_device *dev)
148 struct clusterip_config *c;
150 c = kzalloc(sizeof(*c), GFP_ATOMIC);
156 memcpy(&c->clustermac, &i->clustermac, ETH_ALEN);
157 c->num_total_nodes = i->num_total_nodes;
158 clusterip_config_init_nodelist(c, i);
159 c->hash_mode = i->hash_mode;
160 c->hash_initval = i->hash_initval;
161 atomic_set(&c->refcount, 1);
162 atomic_set(&c->entries, 1);
164 #ifdef CONFIG_PROC_FS
168 /* create proc dir entry */
169 sprintf(buffer, "%u.%u.%u.%u", NIPQUAD(ip));
170 c->pde = proc_create(buffer, S_IWUSR|S_IRUSR,
171 clusterip_procdir, &clusterip_proc_fops);
180 write_lock_bh(&clusterip_lock);
181 list_add(&c->list, &clusterip_configs);
182 write_unlock_bh(&clusterip_lock);
187 #ifdef CONFIG_PROC_FS
189 clusterip_add_node(struct clusterip_config *c, u_int16_t nodenum)
193 nodenum > c->num_total_nodes)
196 /* check if we already have this number in our bitfield */
197 if (test_and_set_bit(nodenum - 1, &c->local_nodes))
204 clusterip_del_node(struct clusterip_config *c, u_int16_t nodenum)
207 nodenum > c->num_total_nodes)
210 if (test_and_clear_bit(nodenum - 1, &c->local_nodes))
217 static inline u_int32_t
218 clusterip_hashfn(const struct sk_buff *skb,
219 const struct clusterip_config *config)
221 const struct iphdr *iph = ip_hdr(skb);
222 unsigned long hashval;
223 u_int16_t sport, dport;
224 const u_int16_t *ports;
226 switch (iph->protocol) {
229 case IPPROTO_UDPLITE:
233 ports = (const void *)iph+iph->ihl*4;
239 printk(KERN_NOTICE "CLUSTERIP: unknown protocol `%u'\n",
244 switch (config->hash_mode) {
245 case CLUSTERIP_HASHMODE_SIP:
246 hashval = jhash_1word(ntohl(iph->saddr),
247 config->hash_initval);
249 case CLUSTERIP_HASHMODE_SIP_SPT:
250 hashval = jhash_2words(ntohl(iph->saddr), sport,
251 config->hash_initval);
253 case CLUSTERIP_HASHMODE_SIP_SPT_DPT:
254 hashval = jhash_3words(ntohl(iph->saddr), sport, dport,
255 config->hash_initval);
258 /* to make gcc happy */
260 /* This cannot happen, unless the check function wasn't called
261 * at rule load time */
262 printk("CLUSTERIP: unknown mode `%u'\n", config->hash_mode);
267 /* node numbers are 1..n, not 0..n */
268 return (((u64)hashval * config->num_total_nodes) >> 32) + 1;
272 clusterip_responsible(const struct clusterip_config *config, u_int32_t hash)
274 return test_bit(hash - 1, &config->local_nodes);
277 /***********************************************************************
279 ***********************************************************************/
282 clusterip_tg(struct sk_buff *skb, const struct net_device *in,
283 const struct net_device *out, unsigned int hooknum,
284 const struct xt_target *target, const void *targinfo)
286 const struct ipt_clusterip_tgt_info *cipinfo = targinfo;
288 enum ip_conntrack_info ctinfo;
291 /* don't need to clusterip_config_get() here, since refcount
292 * is only decremented by destroy() - and ip_tables guarantees
293 * that the ->target() function isn't called after ->destroy() */
295 ct = nf_ct_get(skb, &ctinfo);
297 printk(KERN_ERR "CLUSTERIP: no conntrack!\n");
298 /* FIXME: need to drop invalid ones, since replies
299 * to outgoing connections of other nodes will be
300 * marked as INVALID */
304 /* special case: ICMP error handling. conntrack distinguishes between
305 * error messages (RELATED) and information requests (see below) */
306 if (ip_hdr(skb)->protocol == IPPROTO_ICMP
307 && (ctinfo == IP_CT_RELATED
308 || ctinfo == IP_CT_RELATED+IP_CT_IS_REPLY))
311 /* ip_conntrack_icmp guarantees us that we only have ICMP_ECHO,
312 * TIMESTAMP, INFO_REQUEST or ADDRESS type icmp packets from here
313 * on, which all have an ID field [relevant for hashing]. */
315 hash = clusterip_hashfn(skb, cipinfo->config);
322 case IP_CT_RELATED+IP_CT_IS_REPLY:
323 /* FIXME: we don't handle expectations at the
324 * moment. they can arrive on a different node than
325 * the master connection (e.g. FTP passive mode) */
326 case IP_CT_ESTABLISHED:
327 case IP_CT_ESTABLISHED+IP_CT_IS_REPLY:
334 nf_ct_dump_tuple_ip(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
336 pr_debug("hash=%u ct_hash=%u ", hash, ct->mark);
337 if (!clusterip_responsible(cipinfo->config, hash)) {
338 pr_debug("not responsible\n");
341 pr_debug("responsible\n");
343 /* despite being received via linklayer multicast, this is
344 * actually a unicast IP packet. TCP doesn't like PACKET_MULTICAST */
345 skb->pkt_type = PACKET_HOST;
351 clusterip_tg_check(const char *tablename, const void *e_void,
352 const struct xt_target *target, void *targinfo,
353 unsigned int hook_mask)
355 struct ipt_clusterip_tgt_info *cipinfo = targinfo;
356 const struct ipt_entry *e = e_void;
358 struct clusterip_config *config;
360 if (cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP &&
361 cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP_SPT &&
362 cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP_SPT_DPT) {
363 printk(KERN_WARNING "CLUSTERIP: unknown mode `%u'\n",
368 if (e->ip.dmsk.s_addr != htonl(0xffffffff)
369 || e->ip.dst.s_addr == 0) {
370 printk(KERN_ERR "CLUSTERIP: Please specify destination IP\n");
374 /* FIXME: further sanity checks */
376 config = clusterip_config_find_get(e->ip.dst.s_addr, 1);
378 if (!(cipinfo->flags & CLUSTERIP_FLAG_NEW)) {
379 printk(KERN_WARNING "CLUSTERIP: no config found for %u.%u.%u.%u, need 'new'\n", NIPQUAD(e->ip.dst.s_addr));
382 struct net_device *dev;
384 if (e->ip.iniface[0] == '\0') {
385 printk(KERN_WARNING "CLUSTERIP: Please specify an interface name\n");
389 dev = dev_get_by_name(&init_net, e->ip.iniface);
391 printk(KERN_WARNING "CLUSTERIP: no such interface %s\n", e->ip.iniface);
395 config = clusterip_config_init(cipinfo,
396 e->ip.dst.s_addr, dev);
398 printk(KERN_WARNING "CLUSTERIP: cannot allocate config\n");
402 dev_mc_add(config->dev,config->clustermac, ETH_ALEN, 0);
405 cipinfo->config = config;
407 if (nf_ct_l3proto_try_module_get(target->family) < 0) {
408 printk(KERN_WARNING "can't load conntrack support for "
409 "proto=%u\n", target->family);
416 /* drop reference count of cluster config when rule is deleted */
417 static void clusterip_tg_destroy(const struct xt_target *target, void *targinfo)
419 const struct ipt_clusterip_tgt_info *cipinfo = targinfo;
421 /* if no more entries are referencing the config, remove it
422 * from the list and destroy the proc entry */
423 clusterip_config_entry_put(cipinfo->config);
425 clusterip_config_put(cipinfo->config);
427 nf_ct_l3proto_module_put(target->family);
431 struct compat_ipt_clusterip_tgt_info
434 u_int8_t clustermac[6];
435 u_int16_t num_total_nodes;
436 u_int16_t num_local_nodes;
437 u_int16_t local_nodes[CLUSTERIP_MAX_NODES];
439 u_int32_t hash_initval;
440 compat_uptr_t config;
442 #endif /* CONFIG_COMPAT */
444 static struct xt_target clusterip_tg_reg __read_mostly = {
447 .target = clusterip_tg,
448 .checkentry = clusterip_tg_check,
449 .destroy = clusterip_tg_destroy,
450 .targetsize = sizeof(struct ipt_clusterip_tgt_info),
452 .compatsize = sizeof(struct compat_ipt_clusterip_tgt_info),
453 #endif /* CONFIG_COMPAT */
458 /***********************************************************************
460 ***********************************************************************/
462 /* hardcoded for 48bit ethernet and 32bit ipv4 addresses */
464 u_int8_t src_hw[ETH_ALEN];
466 u_int8_t dst_hw[ETH_ALEN];
468 } __attribute__ ((packed));
471 static void arp_print(struct arp_payload *payload)
473 #define HBUFFERLEN 30
474 char hbuffer[HBUFFERLEN];
476 const char hexbuf[]= "0123456789abcdef";
478 for (k=0, j=0; k < HBUFFERLEN-3 && j < ETH_ALEN; j++) {
479 hbuffer[k++]=hexbuf[(payload->src_hw[j]>>4)&15];
480 hbuffer[k++]=hexbuf[payload->src_hw[j]&15];
485 printk("src %u.%u.%u.%u@%s, dst %u.%u.%u.%u\n",
486 NIPQUAD(payload->src_ip), hbuffer,
487 NIPQUAD(payload->dst_ip));
492 arp_mangle(unsigned int hook,
494 const struct net_device *in,
495 const struct net_device *out,
496 int (*okfn)(struct sk_buff *))
498 struct arphdr *arp = arp_hdr(skb);
499 struct arp_payload *payload;
500 struct clusterip_config *c;
502 /* we don't care about non-ethernet and non-ipv4 ARP */
503 if (arp->ar_hrd != htons(ARPHRD_ETHER)
504 || arp->ar_pro != htons(ETH_P_IP)
505 || arp->ar_pln != 4 || arp->ar_hln != ETH_ALEN)
508 /* we only want to mangle arp requests and replies */
509 if (arp->ar_op != htons(ARPOP_REPLY)
510 && arp->ar_op != htons(ARPOP_REQUEST))
513 payload = (void *)(arp+1);
515 /* if there is no clusterip configuration for the arp reply's
516 * source ip, we don't want to mangle it */
517 c = clusterip_config_find_get(payload->src_ip, 0);
521 /* normally the linux kernel always replies to arp queries of
522 * addresses on different interfacs. However, in the CLUSTERIP case
523 * this wouldn't work, since we didn't subscribe the mcast group on
524 * other interfaces */
526 pr_debug("CLUSTERIP: not mangling arp reply on different "
527 "interface: cip'%s'-skb'%s'\n",
528 c->dev->name, out->name);
529 clusterip_config_put(c);
533 /* mangle reply hardware address */
534 memcpy(payload->src_hw, c->clustermac, arp->ar_hln);
537 pr_debug(KERN_DEBUG "CLUSTERIP mangled arp reply: ");
541 clusterip_config_put(c);
546 static struct nf_hook_ops cip_arp_ops __read_mostly = {
549 .hooknum = NF_ARP_OUT,
553 /***********************************************************************
555 ***********************************************************************/
557 #ifdef CONFIG_PROC_FS
559 struct clusterip_seq_position {
560 unsigned int pos; /* position */
561 unsigned int weight; /* number of bits set == size */
562 unsigned int bit; /* current bit */
563 unsigned long val; /* current value */
566 static void *clusterip_seq_start(struct seq_file *s, loff_t *pos)
568 const struct proc_dir_entry *pde = s->private;
569 struct clusterip_config *c = pde->data;
571 u_int32_t local_nodes;
572 struct clusterip_seq_position *idx;
574 /* FIXME: possible race */
575 local_nodes = c->local_nodes;
576 weight = hweight32(local_nodes);
580 idx = kmalloc(sizeof(struct clusterip_seq_position), GFP_KERNEL);
582 return ERR_PTR(-ENOMEM);
585 idx->weight = weight;
586 idx->bit = ffs(local_nodes);
587 idx->val = local_nodes;
588 clear_bit(idx->bit - 1, &idx->val);
593 static void *clusterip_seq_next(struct seq_file *s, void *v, loff_t *pos)
595 struct clusterip_seq_position *idx = v;
598 if (*pos >= idx->weight) {
602 idx->bit = ffs(idx->val);
603 clear_bit(idx->bit - 1, &idx->val);
607 static void clusterip_seq_stop(struct seq_file *s, void *v)
612 static int clusterip_seq_show(struct seq_file *s, void *v)
614 struct clusterip_seq_position *idx = v;
619 seq_printf(s, "%u", idx->bit);
621 if (idx->pos == idx->weight - 1)
627 static const struct seq_operations clusterip_seq_ops = {
628 .start = clusterip_seq_start,
629 .next = clusterip_seq_next,
630 .stop = clusterip_seq_stop,
631 .show = clusterip_seq_show,
634 static int clusterip_proc_open(struct inode *inode, struct file *file)
636 int ret = seq_open(file, &clusterip_seq_ops);
639 struct seq_file *sf = file->private_data;
640 struct proc_dir_entry *pde = PDE(inode);
641 struct clusterip_config *c = pde->data;
645 clusterip_config_get(c);
651 static int clusterip_proc_release(struct inode *inode, struct file *file)
653 struct proc_dir_entry *pde = PDE(inode);
654 struct clusterip_config *c = pde->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 #define PROC_WRITELEN 10
669 char buffer[PROC_WRITELEN+1];
670 const struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
671 struct clusterip_config *c = pde->data;
672 unsigned long nodenum;
674 if (copy_from_user(buffer, input, PROC_WRITELEN))
677 if (*buffer == '+') {
678 nodenum = simple_strtoul(buffer+1, NULL, 10);
679 if (clusterip_add_node(c, nodenum))
681 } else if (*buffer == '-') {
682 nodenum = simple_strtoul(buffer+1, NULL,10);
683 if (clusterip_del_node(c, nodenum))
691 static const struct file_operations clusterip_proc_fops = {
692 .owner = THIS_MODULE,
693 .open = clusterip_proc_open,
695 .write = clusterip_proc_write,
697 .release = clusterip_proc_release,
700 #endif /* CONFIG_PROC_FS */
702 static int __init clusterip_tg_init(void)
706 ret = xt_register_target(&clusterip_tg_reg);
710 ret = nf_register_hook(&cip_arp_ops);
714 #ifdef CONFIG_PROC_FS
715 clusterip_procdir = proc_mkdir("ipt_CLUSTERIP", init_net.proc_net);
716 if (!clusterip_procdir) {
717 printk(KERN_ERR "CLUSTERIP: Unable to proc dir entry\n");
721 #endif /* CONFIG_PROC_FS */
723 printk(KERN_NOTICE "ClusterIP Version %s loaded successfully\n",
727 #ifdef CONFIG_PROC_FS
729 nf_unregister_hook(&cip_arp_ops);
730 #endif /* CONFIG_PROC_FS */
732 xt_unregister_target(&clusterip_tg_reg);
736 static void __exit clusterip_tg_exit(void)
738 printk(KERN_NOTICE "ClusterIP Version %s unloading\n",
740 #ifdef CONFIG_PROC_FS
741 remove_proc_entry(clusterip_procdir->name, clusterip_procdir->parent);
743 nf_unregister_hook(&cip_arp_ops);
744 xt_unregister_target(&clusterip_tg_reg);
747 module_init(clusterip_tg_init);
748 module_exit(clusterip_tg_exit);