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("iptables target for CLUSTERIP");
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 /* increase the count of entries(rules) using/referencing this config */
81 clusterip_config_entry_get(struct clusterip_config
*c
)
83 atomic_inc(&c
->entries
);
86 /* decrease the count of entries using/referencing this config. If last
87 * entry(rule) is removed, remove the config from lists, but don't free it
88 * yet, since proc-files could still be holding references */
90 clusterip_config_entry_put(struct clusterip_config
*c
)
92 if (atomic_dec_and_test(&c
->entries
)) {
93 write_lock_bh(&clusterip_lock
);
95 write_unlock_bh(&clusterip_lock
);
97 dev_mc_delete(c
->dev
, c
->clustermac
, ETH_ALEN
, 0);
100 /* In case anyone still accesses the file, the open/close
101 * functions are also incrementing the refcount on their own,
102 * so it's safe to remove the entry even if it's in use. */
103 #ifdef CONFIG_PROC_FS
104 remove_proc_entry(c
->pde
->name
, c
->pde
->parent
);
109 static struct clusterip_config
*
110 __clusterip_config_find(__be32 clusterip
)
112 struct list_head
*pos
;
114 list_for_each(pos
, &clusterip_configs
) {
115 struct clusterip_config
*c
= list_entry(pos
,
116 struct clusterip_config
, list
);
117 if (c
->clusterip
== clusterip
)
124 static inline struct clusterip_config
*
125 clusterip_config_find_get(__be32 clusterip
, int entry
)
127 struct clusterip_config
*c
;
129 read_lock_bh(&clusterip_lock
);
130 c
= __clusterip_config_find(clusterip
);
132 read_unlock_bh(&clusterip_lock
);
135 atomic_inc(&c
->refcount
);
137 atomic_inc(&c
->entries
);
138 read_unlock_bh(&clusterip_lock
);
144 clusterip_config_init_nodelist(struct clusterip_config
*c
,
145 const struct ipt_clusterip_tgt_info
*i
)
149 for (n
= 0; n
< i
->num_local_nodes
; n
++)
150 set_bit(i
->local_nodes
[n
] - 1, &c
->local_nodes
);
153 static struct clusterip_config
*
154 clusterip_config_init(struct ipt_clusterip_tgt_info
*i
, __be32 ip
,
155 struct net_device
*dev
)
157 struct clusterip_config
*c
;
159 c
= kzalloc(sizeof(*c
), GFP_ATOMIC
);
165 memcpy(&c
->clustermac
, &i
->clustermac
, ETH_ALEN
);
166 c
->num_total_nodes
= i
->num_total_nodes
;
167 clusterip_config_init_nodelist(c
, i
);
168 c
->hash_mode
= i
->hash_mode
;
169 c
->hash_initval
= i
->hash_initval
;
170 atomic_set(&c
->refcount
, 1);
171 atomic_set(&c
->entries
, 1);
173 #ifdef CONFIG_PROC_FS
177 /* create proc dir entry */
178 sprintf(buffer
, "%u.%u.%u.%u", NIPQUAD(ip
));
179 c
->pde
= create_proc_entry(buffer
, S_IWUSR
|S_IRUSR
,
186 c
->pde
->proc_fops
= &clusterip_proc_fops
;
190 write_lock_bh(&clusterip_lock
);
191 list_add(&c
->list
, &clusterip_configs
);
192 write_unlock_bh(&clusterip_lock
);
197 #ifdef CONFIG_PROC_FS
199 clusterip_add_node(struct clusterip_config
*c
, u_int16_t nodenum
)
203 nodenum
> c
->num_total_nodes
)
206 /* check if we already have this number in our bitfield */
207 if (test_and_set_bit(nodenum
- 1, &c
->local_nodes
))
214 clusterip_del_node(struct clusterip_config
*c
, u_int16_t nodenum
)
217 nodenum
> c
->num_total_nodes
)
220 if (test_and_clear_bit(nodenum
- 1, &c
->local_nodes
))
227 static inline u_int32_t
228 clusterip_hashfn(const struct sk_buff
*skb
,
229 const struct clusterip_config
*config
)
231 const struct iphdr
*iph
= ip_hdr(skb
);
232 unsigned long hashval
;
233 u_int16_t sport
, dport
;
234 const u_int16_t
*ports
;
236 switch (iph
->protocol
) {
239 case IPPROTO_UDPLITE
:
243 ports
= (const void *)iph
+iph
->ihl
*4;
249 printk(KERN_NOTICE
"CLUSTERIP: unknown protocol `%u'\n",
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 printk("CLUSTERIP: unknown mode `%u'\n", config
->hash_mode
);
277 /* node numbers are 1..n, not 0..n */
278 return (hashval
% config
->num_total_nodes
) + 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 target(struct sk_buff
**pskb
,
293 const struct net_device
*in
,
294 const struct net_device
*out
,
295 unsigned int hooknum
,
296 const struct xt_target
*target
,
297 const void *targinfo
)
299 const struct ipt_clusterip_tgt_info
*cipinfo
= targinfo
;
301 enum ip_conntrack_info ctinfo
;
304 /* don't need to clusterip_config_get() here, since refcount
305 * is only decremented by destroy() - and ip_tables guarantees
306 * that the ->target() function isn't called after ->destroy() */
308 ct
= nf_ct_get(*pskb
, &ctinfo
);
310 printk(KERN_ERR
"CLUSTERIP: no conntrack!\n");
311 /* FIXME: need to drop invalid ones, since replies
312 * to outgoing connections of other nodes will be
313 * marked as INVALID */
317 /* special case: ICMP error handling. conntrack distinguishes between
318 * error messages (RELATED) and information requests (see below) */
319 if (ip_hdr(*pskb
)->protocol
== IPPROTO_ICMP
320 && (ctinfo
== IP_CT_RELATED
321 || ctinfo
== IP_CT_RELATED
+IP_CT_IS_REPLY
))
324 /* ip_conntrack_icmp guarantees us that we only have ICMP_ECHO,
325 * TIMESTAMP, INFO_REQUEST or ADDRESS type icmp packets from here
326 * on, which all have an ID field [relevant for hashing]. */
328 hash
= clusterip_hashfn(*pskb
, cipinfo
->config
);
335 case IP_CT_RELATED
+IP_CT_IS_REPLY
:
336 /* FIXME: we don't handle expectations at the
337 * moment. they can arrive on a different node than
338 * the master connection (e.g. FTP passive mode) */
339 case IP_CT_ESTABLISHED
:
340 case IP_CT_ESTABLISHED
+IP_CT_IS_REPLY
:
347 DUMP_TUPLE(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
);
349 pr_debug("hash=%u ct_hash=%u ", hash
, ct
->mark
);
350 if (!clusterip_responsible(cipinfo
->config
, hash
)) {
351 pr_debug("not responsible\n");
354 pr_debug("responsible\n");
356 /* despite being received via linklayer multicast, this is
357 * actually a unicast IP packet. TCP doesn't like PACKET_MULTICAST */
358 (*pskb
)->pkt_type
= PACKET_HOST
;
364 checkentry(const char *tablename
,
366 const struct xt_target
*target
,
368 unsigned int hook_mask
)
370 struct ipt_clusterip_tgt_info
*cipinfo
= targinfo
;
371 const struct ipt_entry
*e
= e_void
;
373 struct clusterip_config
*config
;
375 if (cipinfo
->hash_mode
!= CLUSTERIP_HASHMODE_SIP
&&
376 cipinfo
->hash_mode
!= CLUSTERIP_HASHMODE_SIP_SPT
&&
377 cipinfo
->hash_mode
!= CLUSTERIP_HASHMODE_SIP_SPT_DPT
) {
378 printk(KERN_WARNING
"CLUSTERIP: unknown mode `%u'\n",
383 if (e
->ip
.dmsk
.s_addr
!= htonl(0xffffffff)
384 || e
->ip
.dst
.s_addr
== 0) {
385 printk(KERN_ERR
"CLUSTERIP: Please specify destination IP\n");
389 /* FIXME: further sanity checks */
391 config
= clusterip_config_find_get(e
->ip
.dst
.s_addr
, 1);
393 if (!(cipinfo
->flags
& CLUSTERIP_FLAG_NEW
)) {
394 printk(KERN_WARNING
"CLUSTERIP: no config found for %u.%u.%u.%u, need 'new'\n", NIPQUAD(e
->ip
.dst
.s_addr
));
397 struct net_device
*dev
;
399 if (e
->ip
.iniface
[0] == '\0') {
400 printk(KERN_WARNING
"CLUSTERIP: Please specify an interface name\n");
404 dev
= dev_get_by_name(&init_net
, e
->ip
.iniface
);
406 printk(KERN_WARNING
"CLUSTERIP: no such interface %s\n", e
->ip
.iniface
);
410 config
= clusterip_config_init(cipinfo
,
411 e
->ip
.dst
.s_addr
, dev
);
413 printk(KERN_WARNING
"CLUSTERIP: cannot allocate config\n");
417 dev_mc_add(config
->dev
,config
->clustermac
, ETH_ALEN
, 0);
420 cipinfo
->config
= config
;
422 if (nf_ct_l3proto_try_module_get(target
->family
) < 0) {
423 printk(KERN_WARNING
"can't load conntrack support for "
424 "proto=%d\n", target
->family
);
431 /* drop reference count of cluster config when rule is deleted */
432 static void destroy(const struct xt_target
*target
, void *targinfo
)
434 struct ipt_clusterip_tgt_info
*cipinfo
= targinfo
;
436 /* if no more entries are referencing the config, remove it
437 * from the list and destroy the proc entry */
438 clusterip_config_entry_put(cipinfo
->config
);
440 clusterip_config_put(cipinfo
->config
);
442 nf_ct_l3proto_module_put(target
->family
);
446 struct compat_ipt_clusterip_tgt_info
449 u_int8_t clustermac
[6];
450 u_int16_t num_total_nodes
;
451 u_int16_t num_local_nodes
;
452 u_int16_t local_nodes
[CLUSTERIP_MAX_NODES
];
454 u_int32_t hash_initval
;
455 compat_uptr_t config
;
457 #endif /* CONFIG_COMPAT */
459 static struct xt_target clusterip_tgt __read_mostly
= {
463 .checkentry
= checkentry
,
465 .targetsize
= sizeof(struct ipt_clusterip_tgt_info
),
467 .compatsize
= sizeof(struct compat_ipt_clusterip_tgt_info
),
468 #endif /* CONFIG_COMPAT */
473 /***********************************************************************
475 ***********************************************************************/
477 /* hardcoded for 48bit ethernet and 32bit ipv4 addresses */
479 u_int8_t src_hw
[ETH_ALEN
];
481 u_int8_t dst_hw
[ETH_ALEN
];
483 } __attribute__ ((packed
));
486 static void arp_print(struct arp_payload
*payload
)
488 #define HBUFFERLEN 30
489 char hbuffer
[HBUFFERLEN
];
491 const char hexbuf
[]= "0123456789abcdef";
493 for (k
=0, j
=0; k
< HBUFFERLEN
-3 && j
< ETH_ALEN
; j
++) {
494 hbuffer
[k
++]=hexbuf
[(payload
->src_hw
[j
]>>4)&15];
495 hbuffer
[k
++]=hexbuf
[payload
->src_hw
[j
]&15];
500 printk("src %u.%u.%u.%u@%s, dst %u.%u.%u.%u\n",
501 NIPQUAD(payload
->src_ip
), hbuffer
,
502 NIPQUAD(payload
->dst_ip
));
507 arp_mangle(unsigned int hook
,
508 struct sk_buff
**pskb
,
509 const struct net_device
*in
,
510 const struct net_device
*out
,
511 int (*okfn
)(struct sk_buff
*))
513 struct arphdr
*arp
= arp_hdr(*pskb
);
514 struct arp_payload
*payload
;
515 struct clusterip_config
*c
;
517 /* we don't care about non-ethernet and non-ipv4 ARP */
518 if (arp
->ar_hrd
!= htons(ARPHRD_ETHER
)
519 || arp
->ar_pro
!= htons(ETH_P_IP
)
520 || arp
->ar_pln
!= 4 || arp
->ar_hln
!= ETH_ALEN
)
523 /* we only want to mangle arp requests and replies */
524 if (arp
->ar_op
!= htons(ARPOP_REPLY
)
525 && arp
->ar_op
!= htons(ARPOP_REQUEST
))
528 payload
= (void *)(arp
+1);
530 /* if there is no clusterip configuration for the arp reply's
531 * source ip, we don't want to mangle it */
532 c
= clusterip_config_find_get(payload
->src_ip
, 0);
536 /* normally the linux kernel always replies to arp queries of
537 * addresses on different interfacs. However, in the CLUSTERIP case
538 * this wouldn't work, since we didn't subscribe the mcast group on
539 * other interfaces */
541 pr_debug("CLUSTERIP: not mangling arp reply on different "
542 "interface: cip'%s'-skb'%s'\n",
543 c
->dev
->name
, out
->name
);
544 clusterip_config_put(c
);
548 /* mangle reply hardware address */
549 memcpy(payload
->src_hw
, c
->clustermac
, arp
->ar_hln
);
552 pr_debug(KERN_DEBUG
"CLUSTERIP mangled arp reply: ");
556 clusterip_config_put(c
);
561 static struct nf_hook_ops cip_arp_ops
= {
564 .hooknum
= NF_ARP_OUT
,
568 /***********************************************************************
570 ***********************************************************************/
572 #ifdef CONFIG_PROC_FS
574 struct clusterip_seq_position
{
575 unsigned int pos
; /* position */
576 unsigned int weight
; /* number of bits set == size */
577 unsigned int bit
; /* current bit */
578 unsigned long val
; /* current value */
581 static void *clusterip_seq_start(struct seq_file
*s
, loff_t
*pos
)
583 struct proc_dir_entry
*pde
= s
->private;
584 struct clusterip_config
*c
= pde
->data
;
586 u_int32_t local_nodes
;
587 struct clusterip_seq_position
*idx
;
589 /* FIXME: possible race */
590 local_nodes
= c
->local_nodes
;
591 weight
= hweight32(local_nodes
);
595 idx
= kmalloc(sizeof(struct clusterip_seq_position
), GFP_KERNEL
);
597 return ERR_PTR(-ENOMEM
);
600 idx
->weight
= weight
;
601 idx
->bit
= ffs(local_nodes
);
602 idx
->val
= local_nodes
;
603 clear_bit(idx
->bit
- 1, &idx
->val
);
608 static void *clusterip_seq_next(struct seq_file
*s
, void *v
, loff_t
*pos
)
610 struct clusterip_seq_position
*idx
= (struct clusterip_seq_position
*)v
;
613 if (*pos
>= idx
->weight
) {
617 idx
->bit
= ffs(idx
->val
);
618 clear_bit(idx
->bit
- 1, &idx
->val
);
622 static void clusterip_seq_stop(struct seq_file
*s
, void *v
)
627 static int clusterip_seq_show(struct seq_file
*s
, void *v
)
629 struct clusterip_seq_position
*idx
= (struct clusterip_seq_position
*)v
;
634 seq_printf(s
, "%u", idx
->bit
);
636 if (idx
->pos
== idx
->weight
- 1)
642 static const struct seq_operations clusterip_seq_ops
= {
643 .start
= clusterip_seq_start
,
644 .next
= clusterip_seq_next
,
645 .stop
= clusterip_seq_stop
,
646 .show
= clusterip_seq_show
,
649 static int clusterip_proc_open(struct inode
*inode
, struct file
*file
)
651 int ret
= seq_open(file
, &clusterip_seq_ops
);
654 struct seq_file
*sf
= file
->private_data
;
655 struct proc_dir_entry
*pde
= PDE(inode
);
656 struct clusterip_config
*c
= pde
->data
;
660 clusterip_config_get(c
);
666 static int clusterip_proc_release(struct inode
*inode
, struct file
*file
)
668 struct proc_dir_entry
*pde
= PDE(inode
);
669 struct clusterip_config
*c
= pde
->data
;
672 ret
= seq_release(inode
, file
);
675 clusterip_config_put(c
);
680 static ssize_t
clusterip_proc_write(struct file
*file
, const char __user
*input
,
681 size_t size
, loff_t
*ofs
)
683 #define PROC_WRITELEN 10
684 char buffer
[PROC_WRITELEN
+1];
685 struct proc_dir_entry
*pde
= PDE(file
->f_path
.dentry
->d_inode
);
686 struct clusterip_config
*c
= pde
->data
;
687 unsigned long nodenum
;
689 if (copy_from_user(buffer
, input
, PROC_WRITELEN
))
692 if (*buffer
== '+') {
693 nodenum
= simple_strtoul(buffer
+1, NULL
, 10);
694 if (clusterip_add_node(c
, nodenum
))
696 } else if (*buffer
== '-') {
697 nodenum
= simple_strtoul(buffer
+1, NULL
,10);
698 if (clusterip_del_node(c
, nodenum
))
706 static const struct file_operations clusterip_proc_fops
= {
707 .owner
= THIS_MODULE
,
708 .open
= clusterip_proc_open
,
710 .write
= clusterip_proc_write
,
712 .release
= clusterip_proc_release
,
715 #endif /* CONFIG_PROC_FS */
717 static int __init
ipt_clusterip_init(void)
721 ret
= xt_register_target(&clusterip_tgt
);
725 ret
= nf_register_hook(&cip_arp_ops
);
729 #ifdef CONFIG_PROC_FS
730 clusterip_procdir
= proc_mkdir("ipt_CLUSTERIP", init_net
.proc_net
);
731 if (!clusterip_procdir
) {
732 printk(KERN_ERR
"CLUSTERIP: Unable to proc dir entry\n");
736 #endif /* CONFIG_PROC_FS */
738 printk(KERN_NOTICE
"ClusterIP Version %s loaded successfully\n",
742 #ifdef CONFIG_PROC_FS
744 nf_unregister_hook(&cip_arp_ops
);
745 #endif /* CONFIG_PROC_FS */
747 xt_unregister_target(&clusterip_tgt
);
751 static void __exit
ipt_clusterip_fini(void)
753 printk(KERN_NOTICE
"ClusterIP Version %s unloading\n",
755 #ifdef CONFIG_PROC_FS
756 remove_proc_entry(clusterip_procdir
->name
, clusterip_procdir
->parent
);
758 nf_unregister_hook(&cip_arp_ops
);
759 xt_unregister_target(&clusterip_tgt
);
762 module_init(ipt_clusterip_init
);
763 module_exit(ipt_clusterip_fini
);