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>
34 #define CLUSTERIP_VERSION "0.8"
36 MODULE_LICENSE("GPL");
37 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
38 MODULE_DESCRIPTION("Xtables: CLUSTERIP target");
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
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 */
53 struct proc_dir_entry *pde; /* proc dir entry */
55 enum clusterip_hashmode hash_mode; /* which hashing mode */
56 u_int32_t hash_initval; /* hash initialization */
60 static LIST_HEAD(clusterip_configs);
62 /* clusterip_lock protects the clusterip_configs list */
63 static DEFINE_SPINLOCK(clusterip_lock);
66 static const struct file_operations clusterip_proc_fops;
67 static struct proc_dir_entry *clusterip_procdir;
71 clusterip_config_get(struct clusterip_config *c)
73 atomic_inc(&c->refcount);
77 static void clusterip_config_rcu_free(struct rcu_head *head)
79 kfree(container_of(head, struct clusterip_config, rcu));
83 clusterip_config_put(struct clusterip_config *c)
85 if (atomic_dec_and_test(&c->refcount))
86 call_rcu_bh(&c->rcu, clusterip_config_rcu_free);
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 */
93 clusterip_config_entry_put(struct clusterip_config *c)
96 if (atomic_dec_and_lock(&c->entries, &clusterip_lock)) {
97 list_del_rcu(&c->list);
98 spin_unlock(&clusterip_lock);
101 dev_mc_del(c->dev, c->clustermac);
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
115 static struct clusterip_config *
116 __clusterip_config_find(__be32 clusterip)
118 struct clusterip_config *c;
120 list_for_each_entry_rcu(c, &clusterip_configs, list) {
121 if (c->clusterip == clusterip)
128 static inline struct clusterip_config *
129 clusterip_config_find_get(__be32 clusterip, int entry)
131 struct clusterip_config *c;
134 c = __clusterip_config_find(clusterip);
136 if (unlikely(!atomic_inc_not_zero(&c->refcount)))
139 atomic_inc(&c->entries);
141 rcu_read_unlock_bh();
147 clusterip_config_init_nodelist(struct clusterip_config *c,
148 const struct ipt_clusterip_tgt_info *i)
152 for (n = 0; n < i->num_local_nodes; n++)
153 set_bit(i->local_nodes[n] - 1, &c->local_nodes);
156 static struct clusterip_config *
157 clusterip_config_init(const struct ipt_clusterip_tgt_info *i, __be32 ip,
158 struct net_device *dev)
160 struct clusterip_config *c;
162 c = kzalloc(sizeof(*c), GFP_ATOMIC);
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);
176 #ifdef CONFIG_PROC_FS
180 /* create proc dir entry */
181 sprintf(buffer, "%pI4", &ip);
182 c->pde = proc_create_data(buffer, S_IWUSR|S_IRUSR,
184 &clusterip_proc_fops, c);
192 spin_lock_bh(&clusterip_lock);
193 list_add_rcu(&c->list, &clusterip_configs);
194 spin_unlock_bh(&clusterip_lock);
199 #ifdef CONFIG_PROC_FS
201 clusterip_add_node(struct clusterip_config *c, u_int16_t nodenum)
205 nodenum > c->num_total_nodes)
208 /* check if we already have this number in our bitfield */
209 if (test_and_set_bit(nodenum - 1, &c->local_nodes))
216 clusterip_del_node(struct clusterip_config *c, u_int16_t nodenum)
219 nodenum > c->num_total_nodes)
222 if (test_and_clear_bit(nodenum - 1, &c->local_nodes))
229 static inline u_int32_t
230 clusterip_hashfn(const struct sk_buff *skb,
231 const struct clusterip_config *config)
233 const struct iphdr *iph = ip_hdr(skb);
234 unsigned long hashval;
235 u_int16_t sport = 0, dport = 0;
238 poff = proto_ports_offset(iph->protocol);
240 const u_int16_t *ports;
243 ports = skb_header_pointer(skb, iph->ihl * 4 + poff, 4, _ports);
249 net_info_ratelimited("unknown protocol %u\n", iph->protocol);
252 switch (config->hash_mode) {
253 case CLUSTERIP_HASHMODE_SIP:
254 hashval = jhash_1word(ntohl(iph->saddr),
255 config->hash_initval);
257 case CLUSTERIP_HASHMODE_SIP_SPT:
258 hashval = jhash_2words(ntohl(iph->saddr), sport,
259 config->hash_initval);
261 case CLUSTERIP_HASHMODE_SIP_SPT_DPT:
262 hashval = jhash_3words(ntohl(iph->saddr), sport, dport,
263 config->hash_initval);
266 /* to make gcc happy */
268 /* This cannot happen, unless the check function wasn't called
269 * at rule load time */
270 pr_info("unknown mode %u\n", config->hash_mode);
275 /* node numbers are 1..n, not 0..n */
276 return (((u64)hashval * config->num_total_nodes) >> 32) + 1;
280 clusterip_responsible(const struct clusterip_config *config, u_int32_t hash)
282 return test_bit(hash - 1, &config->local_nodes);
285 /***********************************************************************
287 ***********************************************************************/
290 clusterip_tg(struct sk_buff *skb, const struct xt_action_param *par)
292 const struct ipt_clusterip_tgt_info *cipinfo = par->targinfo;
294 enum ip_conntrack_info ctinfo;
297 /* don't need to clusterip_config_get() here, since refcount
298 * is only decremented by destroy() - and ip_tables guarantees
299 * that the ->target() function isn't called after ->destroy() */
301 ct = nf_ct_get(skb, &ctinfo);
305 /* special case: ICMP error handling. conntrack distinguishes between
306 * error messages (RELATED) and information requests (see below) */
307 if (ip_hdr(skb)->protocol == IPPROTO_ICMP &&
308 (ctinfo == IP_CT_RELATED ||
309 ctinfo == IP_CT_RELATED_REPLY))
312 /* ip_conntrack_icmp guarantees us that we only have ICMP_ECHO,
313 * TIMESTAMP, INFO_REQUEST or ADDRESS type icmp packets from here
314 * on, which all have an ID field [relevant for hashing]. */
316 hash = clusterip_hashfn(skb, cipinfo->config);
323 case IP_CT_RELATED_REPLY:
324 /* FIXME: we don't handle expectations at the moment.
325 * They can arrive on a different node than
326 * the master connection (e.g. FTP passive mode) */
327 case IP_CT_ESTABLISHED:
328 case IP_CT_ESTABLISHED_REPLY:
330 default: /* Prevent gcc warnings */
335 nf_ct_dump_tuple_ip(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
337 pr_debug("hash=%u ct_hash=%u ", hash, ct->mark);
338 if (!clusterip_responsible(cipinfo->config, hash)) {
339 pr_debug("not responsible\n");
342 pr_debug("responsible\n");
344 /* despite being received via linklayer multicast, this is
345 * actually a unicast IP packet. TCP doesn't like PACKET_MULTICAST */
346 skb->pkt_type = PACKET_HOST;
351 static int clusterip_tg_check(const struct xt_tgchk_param *par)
353 struct ipt_clusterip_tgt_info *cipinfo = par->targinfo;
354 const struct ipt_entry *e = par->entryinfo;
355 struct clusterip_config *config;
358 if (cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP &&
359 cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP_SPT &&
360 cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP_SPT_DPT) {
361 pr_info("unknown mode %u\n", cipinfo->hash_mode);
365 if (e->ip.dmsk.s_addr != htonl(0xffffffff) ||
366 e->ip.dst.s_addr == 0) {
367 pr_info("Please specify destination IP\n");
371 /* FIXME: further sanity checks */
373 config = clusterip_config_find_get(e->ip.dst.s_addr, 1);
375 if (!(cipinfo->flags & CLUSTERIP_FLAG_NEW)) {
376 pr_info("no config found for %pI4, need 'new'\n",
380 struct net_device *dev;
382 if (e->ip.iniface[0] == '\0') {
383 pr_info("Please specify an interface name\n");
387 dev = dev_get_by_name(&init_net, e->ip.iniface);
389 pr_info("no such interface %s\n",
394 config = clusterip_config_init(cipinfo,
395 e->ip.dst.s_addr, dev);
400 dev_mc_add(config->dev, config->clustermac);
403 cipinfo->config = config;
405 ret = nf_ct_l3proto_try_module_get(par->family);
407 pr_info("cannot load conntrack support for proto=%u\n",
412 /* drop reference count of cluster config when rule is deleted */
413 static void clusterip_tg_destroy(const struct xt_tgdtor_param *par)
415 const struct ipt_clusterip_tgt_info *cipinfo = par->targinfo;
417 /* if no more entries are referencing the config, remove it
418 * from the list and destroy the proc entry */
419 clusterip_config_entry_put(cipinfo->config);
421 clusterip_config_put(cipinfo->config);
423 nf_ct_l3proto_module_put(par->family);
427 struct compat_ipt_clusterip_tgt_info
430 u_int8_t clustermac[6];
431 u_int16_t num_total_nodes;
432 u_int16_t num_local_nodes;
433 u_int16_t local_nodes[CLUSTERIP_MAX_NODES];
435 u_int32_t hash_initval;
436 compat_uptr_t config;
438 #endif /* CONFIG_COMPAT */
440 static struct xt_target clusterip_tg_reg __read_mostly = {
442 .family = NFPROTO_IPV4,
443 .target = clusterip_tg,
444 .checkentry = clusterip_tg_check,
445 .destroy = clusterip_tg_destroy,
446 .targetsize = sizeof(struct ipt_clusterip_tgt_info),
448 .compatsize = sizeof(struct compat_ipt_clusterip_tgt_info),
449 #endif /* CONFIG_COMPAT */
454 /***********************************************************************
456 ***********************************************************************/
458 /* hardcoded for 48bit ethernet and 32bit ipv4 addresses */
460 u_int8_t src_hw[ETH_ALEN];
462 u_int8_t dst_hw[ETH_ALEN];
467 static void arp_print(struct arp_payload *payload)
469 #define HBUFFERLEN 30
470 char hbuffer[HBUFFERLEN];
473 for (k=0, j=0; k < HBUFFERLEN-3 && j < ETH_ALEN; j++) {
474 hbuffer[k++] = hex_asc_hi(payload->src_hw[j]);
475 hbuffer[k++] = hex_asc_lo(payload->src_hw[j]);
480 pr_debug("src %pI4@%s, dst %pI4\n",
481 &payload->src_ip, hbuffer, &payload->dst_ip);
486 arp_mangle(const struct nf_hook_ops *ops,
488 const struct net_device *in,
489 const struct net_device *out,
490 int (*okfn)(struct sk_buff *))
492 struct arphdr *arp = arp_hdr(skb);
493 struct arp_payload *payload;
494 struct clusterip_config *c;
496 /* we don't care about non-ethernet and non-ipv4 ARP */
497 if (arp->ar_hrd != htons(ARPHRD_ETHER) ||
498 arp->ar_pro != htons(ETH_P_IP) ||
499 arp->ar_pln != 4 || arp->ar_hln != ETH_ALEN)
502 /* we only want to mangle arp requests and replies */
503 if (arp->ar_op != htons(ARPOP_REPLY) &&
504 arp->ar_op != htons(ARPOP_REQUEST))
507 payload = (void *)(arp+1);
509 /* if there is no clusterip configuration for the arp reply's
510 * source ip, we don't want to mangle it */
511 c = clusterip_config_find_get(payload->src_ip, 0);
515 /* normally the linux kernel always replies to arp queries of
516 * addresses on different interfacs. However, in the CLUSTERIP case
517 * this wouldn't work, since we didn't subscribe the mcast group on
518 * other interfaces */
520 pr_debug("not mangling arp reply on different "
521 "interface: cip'%s'-skb'%s'\n",
522 c->dev->name, out->name);
523 clusterip_config_put(c);
527 /* mangle reply hardware address */
528 memcpy(payload->src_hw, c->clustermac, arp->ar_hln);
531 pr_debug("mangled arp reply: ");
535 clusterip_config_put(c);
540 static struct nf_hook_ops cip_arp_ops __read_mostly = {
543 .hooknum = NF_ARP_OUT,
547 /***********************************************************************
549 ***********************************************************************/
551 #ifdef CONFIG_PROC_FS
553 struct clusterip_seq_position {
554 unsigned int pos; /* position */
555 unsigned int weight; /* number of bits set == size */
556 unsigned int bit; /* current bit */
557 unsigned long val; /* current value */
560 static void *clusterip_seq_start(struct seq_file *s, loff_t *pos)
562 struct clusterip_config *c = s->private;
564 u_int32_t local_nodes;
565 struct clusterip_seq_position *idx;
567 /* FIXME: possible race */
568 local_nodes = c->local_nodes;
569 weight = hweight32(local_nodes);
573 idx = kmalloc(sizeof(struct clusterip_seq_position), GFP_KERNEL);
575 return ERR_PTR(-ENOMEM);
578 idx->weight = weight;
579 idx->bit = ffs(local_nodes);
580 idx->val = local_nodes;
581 clear_bit(idx->bit - 1, &idx->val);
586 static void *clusterip_seq_next(struct seq_file *s, void *v, loff_t *pos)
588 struct clusterip_seq_position *idx = v;
591 if (*pos >= idx->weight) {
595 idx->bit = ffs(idx->val);
596 clear_bit(idx->bit - 1, &idx->val);
600 static void clusterip_seq_stop(struct seq_file *s, void *v)
606 static int clusterip_seq_show(struct seq_file *s, void *v)
608 struct clusterip_seq_position *idx = v;
613 seq_printf(s, "%u", idx->bit);
615 if (idx->pos == idx->weight - 1)
621 static const struct seq_operations clusterip_seq_ops = {
622 .start = clusterip_seq_start,
623 .next = clusterip_seq_next,
624 .stop = clusterip_seq_stop,
625 .show = clusterip_seq_show,
628 static int clusterip_proc_open(struct inode *inode, struct file *file)
630 int ret = seq_open(file, &clusterip_seq_ops);
633 struct seq_file *sf = file->private_data;
634 struct clusterip_config *c = PDE_DATA(inode);
638 clusterip_config_get(c);
644 static int clusterip_proc_release(struct inode *inode, struct file *file)
646 struct clusterip_config *c = PDE_DATA(inode);
649 ret = seq_release(inode, file);
652 clusterip_config_put(c);
657 static ssize_t clusterip_proc_write(struct file *file, const char __user *input,
658 size_t size, loff_t *ofs)
660 struct clusterip_config *c = PDE_DATA(file_inode(file));
661 #define PROC_WRITELEN 10
662 char buffer[PROC_WRITELEN+1];
663 unsigned long nodenum;
666 if (size > PROC_WRITELEN)
668 if (copy_from_user(buffer, input, size))
672 if (*buffer == '+') {
673 rc = kstrtoul(buffer+1, 10, &nodenum);
676 if (clusterip_add_node(c, nodenum))
678 } else if (*buffer == '-') {
679 rc = kstrtoul(buffer+1, 10, &nodenum);
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 proc_remove(clusterip_procdir);
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);