Staging
v0.5.2
v0.5.2
ipt_CLUSTERIP.c
/* Cluster IP hashmark target
* (C) 2003-2004 by Harald Welte <laforge@netfilter.org>
* based on ideas of Fabio Olive Leite <olive@unixforge.org>
*
* Development of this code funded by SuSE Linux AG, http://www.suse.com/
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/jhash.h>
#include <linux/bitops.h>
#include <linux/skbuff.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/icmp.h>
#include <linux/if_arp.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <net/checksum.h>
#include <linux/netfilter_arp.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv4/ipt_CLUSTERIP.h>
#include <net/netfilter/nf_conntrack_compat.h>
#define CLUSTERIP_VERSION "0.8"
#define DEBUG_CLUSTERIP
#ifdef DEBUG_CLUSTERIP
#define DEBUGP printk
#else
#define DEBUGP
#endif
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
MODULE_DESCRIPTION("iptables target for CLUSTERIP");
struct clusterip_config {
struct list_head list; /* list of all configs */
atomic_t refcount; /* reference count */
atomic_t entries; /* number of entries/rules
* referencing us */
__be32 clusterip; /* the IP address */
u_int8_t clustermac[ETH_ALEN]; /* the MAC address */
struct net_device *dev; /* device */
u_int16_t num_total_nodes; /* total number of nodes */
unsigned long local_nodes; /* node number array */
#ifdef CONFIG_PROC_FS
struct proc_dir_entry *pde; /* proc dir entry */
#endif
enum clusterip_hashmode hash_mode; /* which hashing mode */
u_int32_t hash_initval; /* hash initialization */
};
static LIST_HEAD(clusterip_configs);
/* clusterip_lock protects the clusterip_configs list */
static DEFINE_RWLOCK(clusterip_lock);
#ifdef CONFIG_PROC_FS
static struct file_operations clusterip_proc_fops;
static struct proc_dir_entry *clusterip_procdir;
#endif
static inline void
clusterip_config_get(struct clusterip_config *c)
{
atomic_inc(&c->refcount);
}
static inline void
clusterip_config_put(struct clusterip_config *c)
{
if (atomic_dec_and_test(&c->refcount))
kfree(c);
}
/* increase the count of entries(rules) using/referencing this config */
static inline void
clusterip_config_entry_get(struct clusterip_config *c)
{
atomic_inc(&c->entries);
}
/* decrease the count of entries using/referencing this config. If last
* entry(rule) is removed, remove the config from lists, but don't free it
* yet, since proc-files could still be holding references */
static inline void
clusterip_config_entry_put(struct clusterip_config *c)
{
if (atomic_dec_and_test(&c->entries)) {
write_lock_bh(&clusterip_lock);
list_del(&c->list);
write_unlock_bh(&clusterip_lock);
dev_mc_delete(c->dev, c->clustermac, ETH_ALEN, 0);
dev_put(c->dev);
/* In case anyone still accesses the file, the open/close
* functions are also incrementing the refcount on their own,
* so it's safe to remove the entry even if it's in use. */
#ifdef CONFIG_PROC_FS
remove_proc_entry(c->pde->name, c->pde->parent);
#endif
}
}
static struct clusterip_config *
__clusterip_config_find(__be32 clusterip)
{
struct list_head *pos;
list_for_each(pos, &clusterip_configs) {
struct clusterip_config *c = list_entry(pos,
struct clusterip_config, list);
if (c->clusterip == clusterip) {
return c;
}
}
return NULL;
}
static inline struct clusterip_config *
clusterip_config_find_get(__be32 clusterip, int entry)
{
struct clusterip_config *c;
read_lock_bh(&clusterip_lock);
c = __clusterip_config_find(clusterip);
if (!c) {
read_unlock_bh(&clusterip_lock);
return NULL;
}
atomic_inc(&c->refcount);
if (entry)
atomic_inc(&c->entries);
read_unlock_bh(&clusterip_lock);
return c;
}
static void
clusterip_config_init_nodelist(struct clusterip_config *c,
const struct ipt_clusterip_tgt_info *i)
{
int n;
for (n = 0; n < i->num_local_nodes; n++) {
set_bit(i->local_nodes[n] - 1, &c->local_nodes);
}
}
static struct clusterip_config *
clusterip_config_init(struct ipt_clusterip_tgt_info *i, __be32 ip,
struct net_device *dev)
{
struct clusterip_config *c;
c = kzalloc(sizeof(*c), GFP_ATOMIC);
if (!c)
return NULL;
c->dev = dev;
c->clusterip = ip;
memcpy(&c->clustermac, &i->clustermac, ETH_ALEN);
c->num_total_nodes = i->num_total_nodes;
clusterip_config_init_nodelist(c, i);
c->hash_mode = i->hash_mode;
c->hash_initval = i->hash_initval;
atomic_set(&c->refcount, 1);
atomic_set(&c->entries, 1);
#ifdef CONFIG_PROC_FS
{
char buffer[16];
/* create proc dir entry */
sprintf(buffer, "%u.%u.%u.%u", NIPQUAD(ip));
c->pde = create_proc_entry(buffer, S_IWUSR|S_IRUSR,
clusterip_procdir);
if (!c->pde) {
kfree(c);
return NULL;
}
}
c->pde->proc_fops = &clusterip_proc_fops;
c->pde->data = c;
#endif
write_lock_bh(&clusterip_lock);
list_add(&c->list, &clusterip_configs);
write_unlock_bh(&clusterip_lock);
return c;
}
#ifdef CONFIG_PROC_FS
static int
clusterip_add_node(struct clusterip_config *c, u_int16_t nodenum)
{
if (nodenum == 0 ||
nodenum > c->num_total_nodes)
return 1;
/* check if we already have this number in our bitfield */
if (test_and_set_bit(nodenum - 1, &c->local_nodes))
return 1;
return 0;
}
static int
clusterip_del_node(struct clusterip_config *c, u_int16_t nodenum)
{
if (nodenum == 0 ||
nodenum > c->num_total_nodes)
return 1;
if (test_and_clear_bit(nodenum - 1, &c->local_nodes))
return 0;
return 1;
}
#endif
static inline u_int32_t
clusterip_hashfn(struct sk_buff *skb, struct clusterip_config *config)
{
struct iphdr *iph = skb->nh.iph;
unsigned long hashval;
u_int16_t sport, dport;
u_int16_t *ports;
switch (iph->protocol) {
case IPPROTO_TCP:
case IPPROTO_UDP:
case IPPROTO_SCTP:
case IPPROTO_DCCP:
case IPPROTO_ICMP:
ports = (void *)iph+iph->ihl*4;
sport = ports[0];
dport = ports[1];
break;
default:
if (net_ratelimit()) {
printk(KERN_NOTICE "CLUSTERIP: unknown protocol `%u'\n",
iph->protocol);
}
sport = dport = 0;
}
switch (config->hash_mode) {
case CLUSTERIP_HASHMODE_SIP:
hashval = jhash_1word(ntohl(iph->saddr),
config->hash_initval);
break;
case CLUSTERIP_HASHMODE_SIP_SPT:
hashval = jhash_2words(ntohl(iph->saddr), sport,
config->hash_initval);
break;
case CLUSTERIP_HASHMODE_SIP_SPT_DPT:
hashval = jhash_3words(ntohl(iph->saddr), sport, dport,
config->hash_initval);
break;
default:
/* to make gcc happy */
hashval = 0;
/* This cannot happen, unless the check function wasn't called
* at rule load time */
printk("CLUSTERIP: unknown mode `%u'\n", config->hash_mode);
BUG();
break;
}
/* node numbers are 1..n, not 0..n */
return ((hashval % config->num_total_nodes)+1);
}
static inline int
clusterip_responsible(struct clusterip_config *config, u_int32_t hash)
{
return test_bit(hash - 1, &config->local_nodes);
}
/***********************************************************************
* IPTABLES TARGET
***********************************************************************/
static unsigned int
target(struct sk_buff **pskb,
const struct net_device *in,
const struct net_device *out,
unsigned int hooknum,
const struct xt_target *target,
const void *targinfo)
{
const struct ipt_clusterip_tgt_info *cipinfo = targinfo;
enum ip_conntrack_info ctinfo;
u_int32_t *mark, hash;
/* don't need to clusterip_config_get() here, since refcount
* is only decremented by destroy() - and ip_tables guarantees
* that the ->target() function isn't called after ->destroy() */
mark = nf_ct_get_mark((*pskb), &ctinfo);
if (mark == NULL) {
printk(KERN_ERR "CLUSTERIP: no conntrack!\n");
/* FIXME: need to drop invalid ones, since replies
* to outgoing connections of other nodes will be
* marked as INVALID */
return NF_DROP;
}
/* special case: ICMP error handling. conntrack distinguishes between
* error messages (RELATED) and information requests (see below) */
if ((*pskb)->nh.iph->protocol == IPPROTO_ICMP
&& (ctinfo == IP_CT_RELATED
|| ctinfo == IP_CT_RELATED+IP_CT_IS_REPLY))
return IPT_CONTINUE;
/* ip_conntrack_icmp guarantees us that we only have ICMP_ECHO,
* TIMESTAMP, INFO_REQUEST or ADDRESS type icmp packets from here
* on, which all have an ID field [relevant for hashing]. */
hash = clusterip_hashfn(*pskb, cipinfo->config);
switch (ctinfo) {
case IP_CT_NEW:
*mark = hash;
break;
case IP_CT_RELATED:
case IP_CT_RELATED+IP_CT_IS_REPLY:
/* FIXME: we don't handle expectations at the
* moment. they can arrive on a different node than
* the master connection (e.g. FTP passive mode) */
case IP_CT_ESTABLISHED:
case IP_CT_ESTABLISHED+IP_CT_IS_REPLY:
break;
default:
break;
}
#ifdef DEBUG_CLUSTERP
DUMP_TUPLE(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
#endif
DEBUGP("hash=%u ct_hash=%u ", hash, *mark);
if (!clusterip_responsible(cipinfo->config, hash)) {
DEBUGP("not responsible\n");
return NF_DROP;
}
DEBUGP("responsible\n");
/* despite being received via linklayer multicast, this is
* actually a unicast IP packet. TCP doesn't like PACKET_MULTICAST */
(*pskb)->pkt_type = PACKET_HOST;
return IPT_CONTINUE;
}
static int
checkentry(const char *tablename,
const void *e_void,
const struct xt_target *target,
void *targinfo,
unsigned int hook_mask)
{
struct ipt_clusterip_tgt_info *cipinfo = targinfo;
const struct ipt_entry *e = e_void;
struct clusterip_config *config;
if (cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP &&
cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP_SPT &&
cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP_SPT_DPT) {
printk(KERN_WARNING "CLUSTERIP: unknown mode `%u'\n",
cipinfo->hash_mode);
return 0;
}
if (e->ip.dmsk.s_addr != htonl(0xffffffff)
|| e->ip.dst.s_addr == 0) {
printk(KERN_ERR "CLUSTERIP: Please specify destination IP\n");
return 0;
}
/* FIXME: further sanity checks */
config = clusterip_config_find_get(e->ip.dst.s_addr, 1);
if (config) {
if (cipinfo->config != NULL) {
/* Case A: This is an entry that gets reloaded, since
* it still has a cipinfo->config pointer. Simply
* increase the entry refcount and return */
if (cipinfo->config != config) {
printk(KERN_ERR "CLUSTERIP: Reloaded entry "
"has invalid config pointer!\n");
return 0;
}
clusterip_config_entry_get(cipinfo->config);
} else {
/* Case B: This is a new rule referring to an existing
* clusterip config. */
cipinfo->config = config;
clusterip_config_entry_get(cipinfo->config);
}
} else {
/* Case C: This is a completely new clusterip config */
if (!(cipinfo->flags & CLUSTERIP_FLAG_NEW)) {
printk(KERN_WARNING "CLUSTERIP: no config found for %u.%u.%u.%u, need 'new'\n", NIPQUAD(e->ip.dst.s_addr));
return 0;
} else {
struct net_device *dev;
if (e->ip.iniface[0] == '\0') {
printk(KERN_WARNING "CLUSTERIP: Please specify an interface name\n");
return 0;
}
dev = dev_get_by_name(e->ip.iniface);
if (!dev) {
printk(KERN_WARNING "CLUSTERIP: no such interface %s\n", e->ip.iniface);
return 0;
}
config = clusterip_config_init(cipinfo,
e->ip.dst.s_addr, dev);
if (!config) {
printk(KERN_WARNING "CLUSTERIP: cannot allocate config\n");
dev_put(dev);
return 0;
}
dev_mc_add(config->dev,config->clustermac, ETH_ALEN, 0);
}
cipinfo->config = config;
}
if (nf_ct_l3proto_try_module_get(target->family) < 0) {
printk(KERN_WARNING "can't load conntrack support for "
"proto=%d\n", target->family);
return 0;
}
return 1;
}
/* drop reference count of cluster config when rule is deleted */
static void destroy(const struct xt_target *target, void *targinfo)
{
struct ipt_clusterip_tgt_info *cipinfo = targinfo;
/* if no more entries are referencing the config, remove it
* from the list and destroy the proc entry */
clusterip_config_entry_put(cipinfo->config);
clusterip_config_put(cipinfo->config);
nf_ct_l3proto_module_put(target->family);
}
static struct ipt_target clusterip_tgt = {
.name = "CLUSTERIP",
.target = target,
.targetsize = sizeof(struct ipt_clusterip_tgt_info),
.checkentry = checkentry,
.destroy = destroy,
.me = THIS_MODULE
};
/***********************************************************************
* ARP MANGLING CODE
***********************************************************************/
/* hardcoded for 48bit ethernet and 32bit ipv4 addresses */
struct arp_payload {
u_int8_t src_hw[ETH_ALEN];
__be32 src_ip;
u_int8_t dst_hw[ETH_ALEN];
__be32 dst_ip;
} __attribute__ ((packed));
#ifdef CLUSTERIP_DEBUG
static void arp_print(struct arp_payload *payload)
{
#define HBUFFERLEN 30
char hbuffer[HBUFFERLEN];
int j,k;
const char hexbuf[]= "0123456789abcdef";
for (k=0, j=0; k < HBUFFERLEN-3 && j < ETH_ALEN; j++) {
hbuffer[k++]=hexbuf[(payload->src_hw[j]>>4)&15];
hbuffer[k++]=hexbuf[payload->src_hw[j]&15];
hbuffer[k++]=':';
}
hbuffer[--k]='\0';
printk("src %u.%u.%u.%u@%s, dst %u.%u.%u.%u\n",
NIPQUAD(payload->src_ip), hbuffer,
NIPQUAD(payload->dst_ip));
}
#endif
static unsigned int
arp_mangle(unsigned int hook,
struct sk_buff **pskb,
const struct net_device *in,
const struct net_device *out,
int (*okfn)(struct sk_buff *))
{
struct arphdr *arp = (*pskb)->nh.arph;
struct arp_payload *payload;
struct clusterip_config *c;
/* we don't care about non-ethernet and non-ipv4 ARP */
if (arp->ar_hrd != htons(ARPHRD_ETHER)
|| arp->ar_pro != htons(ETH_P_IP)
|| arp->ar_pln != 4 || arp->ar_hln != ETH_ALEN)
return NF_ACCEPT;
/* we only want to mangle arp requests and replies */
if (arp->ar_op != htons(ARPOP_REPLY)
&& arp->ar_op != htons(ARPOP_REQUEST))
return NF_ACCEPT;
payload = (void *)(arp+1);
/* if there is no clusterip configuration for the arp reply's
* source ip, we don't want to mangle it */
c = clusterip_config_find_get(payload->src_ip, 0);
if (!c)
return NF_ACCEPT;
/* normally the linux kernel always replies to arp queries of
* addresses on different interfacs. However, in the CLUSTERIP case
* this wouldn't work, since we didn't subscribe the mcast group on
* other interfaces */
if (c->dev != out) {
DEBUGP("CLUSTERIP: not mangling arp reply on different "
"interface: cip'%s'-skb'%s'\n", c->dev->name, out->name);
clusterip_config_put(c);
return NF_ACCEPT;
}
/* mangle reply hardware address */
memcpy(payload->src_hw, c->clustermac, arp->ar_hln);
#ifdef CLUSTERIP_DEBUG
DEBUGP(KERN_DEBUG "CLUSTERIP mangled arp reply: ");
arp_print(payload);
#endif
clusterip_config_put(c);
return NF_ACCEPT;
}
static struct nf_hook_ops cip_arp_ops = {
.hook = arp_mangle,
.pf = NF_ARP,
.hooknum = NF_ARP_OUT,
.priority = -1
};
/***********************************************************************
* PROC DIR HANDLING
***********************************************************************/
#ifdef CONFIG_PROC_FS
struct clusterip_seq_position {
unsigned int pos; /* position */
unsigned int weight; /* number of bits set == size */
unsigned int bit; /* current bit */
unsigned long val; /* current value */
};
static void *clusterip_seq_start(struct seq_file *s, loff_t *pos)
{
struct proc_dir_entry *pde = s->private;
struct clusterip_config *c = pde->data;
unsigned int weight;
u_int32_t local_nodes;
struct clusterip_seq_position *idx;
/* FIXME: possible race */
local_nodes = c->local_nodes;
weight = hweight32(local_nodes);
if (*pos >= weight)
return NULL;
idx = kmalloc(sizeof(struct clusterip_seq_position), GFP_KERNEL);
if (!idx)
return ERR_PTR(-ENOMEM);
idx->pos = *pos;
idx->weight = weight;
idx->bit = ffs(local_nodes);
idx->val = local_nodes;
clear_bit(idx->bit - 1, &idx->val);
return idx;
}
static void *clusterip_seq_next(struct seq_file *s, void *v, loff_t *pos)
{
struct clusterip_seq_position *idx = (struct clusterip_seq_position *)v;
*pos = ++idx->pos;
if (*pos >= idx->weight) {
kfree(v);
return NULL;
}
idx->bit = ffs(idx->val);
clear_bit(idx->bit - 1, &idx->val);
return idx;
}
static void clusterip_seq_stop(struct seq_file *s, void *v)
{
kfree(v);
}
static int clusterip_seq_show(struct seq_file *s, void *v)
{
struct clusterip_seq_position *idx = (struct clusterip_seq_position *)v;
if (idx->pos != 0)
seq_putc(s, ',');
seq_printf(s, "%u", idx->bit);
if (idx->pos == idx->weight - 1)
seq_putc(s, '\n');
return 0;
}
static struct seq_operations clusterip_seq_ops = {
.start = clusterip_seq_start,
.next = clusterip_seq_next,
.stop = clusterip_seq_stop,
.show = clusterip_seq_show,
};
static int clusterip_proc_open(struct inode *inode, struct file *file)
{
int ret = seq_open(file, &clusterip_seq_ops);
if (!ret) {
struct seq_file *sf = file->private_data;
struct proc_dir_entry *pde = PDE(inode);
struct clusterip_config *c = pde->data;
sf->private = pde;
clusterip_config_get(c);
}
return ret;
}
static int clusterip_proc_release(struct inode *inode, struct file *file)
{
struct proc_dir_entry *pde = PDE(inode);
struct clusterip_config *c = pde->data;
int ret;
ret = seq_release(inode, file);
if (!ret)
clusterip_config_put(c);
return ret;
}
static ssize_t clusterip_proc_write(struct file *file, const char __user *input,
size_t size, loff_t *ofs)
{
#define PROC_WRITELEN 10
char buffer[PROC_WRITELEN+1];
struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
struct clusterip_config *c = pde->data;
unsigned long nodenum;
if (copy_from_user(buffer, input, PROC_WRITELEN))
return -EFAULT;
if (*buffer == '+') {
nodenum = simple_strtoul(buffer+1, NULL, 10);
if (clusterip_add_node(c, nodenum))
return -ENOMEM;
} else if (*buffer == '-') {
nodenum = simple_strtoul(buffer+1, NULL,10);
if (clusterip_del_node(c, nodenum))
return -ENOENT;
} else
return -EIO;
return size;
}
static struct file_operations clusterip_proc_fops = {
.owner = THIS_MODULE,
.open = clusterip_proc_open,
.read = seq_read,
.write = clusterip_proc_write,
.llseek = seq_lseek,
.release = clusterip_proc_release,
};
#endif /* CONFIG_PROC_FS */
static int __init ipt_clusterip_init(void)
{
int ret;
ret = ipt_register_target(&clusterip_tgt);
if (ret < 0)
return ret;
ret = nf_register_hook(&cip_arp_ops);
if (ret < 0)
goto cleanup_target;
#ifdef CONFIG_PROC_FS
clusterip_procdir = proc_mkdir("ipt_CLUSTERIP", proc_net);
if (!clusterip_procdir) {
printk(KERN_ERR "CLUSTERIP: Unable to proc dir entry\n");
ret = -ENOMEM;
goto cleanup_hook;
}
#endif /* CONFIG_PROC_FS */
printk(KERN_NOTICE "ClusterIP Version %s loaded successfully\n",
CLUSTERIP_VERSION);
return 0;
#ifdef CONFIG_PROC_FS
cleanup_hook:
nf_unregister_hook(&cip_arp_ops);
#endif /* CONFIG_PROC_FS */
cleanup_target:
ipt_unregister_target(&clusterip_tgt);
return ret;
}
static void __exit ipt_clusterip_fini(void)
{
printk(KERN_NOTICE "ClusterIP Version %s unloading\n",
CLUSTERIP_VERSION);
#ifdef CONFIG_PROC_FS
remove_proc_entry(clusterip_procdir->name, clusterip_procdir->parent);
#endif
nf_unregister_hook(&cip_arp_ops);
ipt_unregister_target(&clusterip_tgt);
}
module_init(ipt_clusterip_init);
module_exit(ipt_clusterip_fini);