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Commit 136e92bb authored by KOVACS Krisztian's avatar KOVACS Krisztian Committed by David S. Miller
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[NETFILTER] CLUSTERIP: use a bitmap to store node responsibility data 



Instead of maintaining an array containing a list of nodes this instance
is responsible for let's use a simple bitmap. This provides the
following features:

  * clusterip_responsible() and the add_node()/delete_node() operations
    become very simple and don't need locking
  * the config structure is much smaller

In spite of the completely different internal data representation the
user-space interface remains almost unchanged; the only difference is
that the proc file does not list nodes in the order they were added.
(The target info structure remains the same.)

Signed-off-by: default avatarKOVACS Krisztian <hidden@balabit.hu>
Signed-off-by: default avatarHarald Welte <laforge@netfilter.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 44513624

net/ipv4/netfilter/ipt_CLUSTERIP.c

+61 −82
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#include <linux/config.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>
@@ -30,7 +31,7 @@ 
#include <linux/netfilter_ipv4/ipt_CLUSTERIP.h>

#include <linux/netfilter_ipv4/ip_conntrack.h>



#define CLUSTERIP_VERSION "0.7"

#define CLUSTERIP_VERSION "0.8"



#define DEBUG_CLUSTERIP
@@ -56,8 +57,7 @@ struct clusterip_config { 
	u_int8_t clustermac[ETH_ALEN];		/* the MAC address */

	struct net_device *dev;			/* device */

	u_int16_t num_total_nodes;		/* total number of nodes */

	u_int16_t num_local_nodes;		/* number of local nodes */

	u_int16_t local_nodes[CLUSTERIP_MAX_NODES];	/* node number array */

	unsigned long local_nodes;		/* node number array */



#ifdef CONFIG_PROC_FS

	struct proc_dir_entry *pde;		/* proc dir entry */
@@ -68,8 +68,7 @@ struct clusterip_config { 


static LIST_HEAD(clusterip_configs);



/* clusterip_lock protects the clusterip_configs list _AND_ the configurable

 * data within all structurses (num_local_nodes, local_nodes[]) */

/* clusterip_lock protects the clusterip_configs list */

static DEFINE_RWLOCK(clusterip_lock);



#ifdef CONFIG_PROC_FS
@@ -156,6 +155,17 @@ clusterip_config_find_get(u_int32_t clusterip, int entry) 
	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, u_int32_t ip,

			struct net_device *dev)
@@ -172,8 +182,7 @@ clusterip_config_init(struct ipt_clusterip_tgt_info *i, u_int32_t ip, 
	c->clusterip = ip;

	memcpy(&c->clustermac, &i->clustermac, ETH_ALEN);

	c->num_total_nodes = i->num_total_nodes;

	c->num_local_nodes = i->num_local_nodes;

	memcpy(&c->local_nodes, &i->local_nodes, sizeof(c->local_nodes));

	clusterip_config_init_nodelist(c, i);

	c->hash_mode = i->hash_mode;

	c->hash_initval = i->hash_initval;

	atomic_set(&c->refcount, 1);
@@ -201,53 +210,28 @@ clusterip_config_init(struct ipt_clusterip_tgt_info *i, u_int32_t ip, 
static int

clusterip_add_node(struct clusterip_config *c, u_int16_t nodenum)

{

	int i;



	write_lock_bh(&clusterip_lock);



	if (c->num_local_nodes >= CLUSTERIP_MAX_NODES

	    || nodenum > CLUSTERIP_MAX_NODES) {

		write_unlock_bh(&clusterip_lock);

	if (nodenum == 0 ||

	    nodenum > c->num_total_nodes)

		return 1;

	}



	/* check if we alrady have this number in our array */

	for (i = 0; i < c->num_local_nodes; i++) {

		if (c->local_nodes[i] == nodenum) {

			write_unlock_bh(&clusterip_lock);

	/* check if we already have this number in our bitfield */

	if (test_and_set_bit(nodenum - 1, &c->local_nodes))

		return 1;

		}

	}



	c->local_nodes[c->num_local_nodes++] = nodenum;



	write_unlock_bh(&clusterip_lock);

	return 0;

}



static int

clusterip_del_node(struct clusterip_config *c, u_int16_t nodenum)

{

	int i;



	write_lock_bh(&clusterip_lock);



	if (c->num_local_nodes <= 1 || nodenum > CLUSTERIP_MAX_NODES) {

		write_unlock_bh(&clusterip_lock);

	if (nodenum == 0 ||

	    nodenum > c->num_total_nodes)

		return 1;

	}

		

	for (i = 0; i < c->num_local_nodes; i++) {

		if (c->local_nodes[i] == nodenum) {

			int size = sizeof(u_int16_t)*(c->num_local_nodes-(i+1));

			memmove(&c->local_nodes[i], &c->local_nodes[i+1], size);

			c->num_local_nodes--;

			write_unlock_bh(&clusterip_lock);

	if (test_and_clear_bit(nodenum - 1, &c->local_nodes))

		return 0;

		}

	}



	write_unlock_bh(&clusterip_lock);

	return 1;

}
@@ -315,25 +299,7 @@ clusterip_hashfn(struct sk_buff *skb, struct clusterip_config *config) 
static inline int

clusterip_responsible(struct clusterip_config *config, u_int32_t hash)

{

	int i;



	read_lock_bh(&clusterip_lock);



	if (config->num_local_nodes == 0) {

		read_unlock_bh(&clusterip_lock);

		return 0;

	}



	for (i = 0; i < config->num_local_nodes; i++) {

		if (config->local_nodes[i] == hash) {

			read_unlock_bh(&clusterip_lock);

			return 1;

		}

	}



	read_unlock_bh(&clusterip_lock);



	return 0;

	return test_bit(hash - 1, &config->local_nodes);

}



/***********************************************************************
@@ -618,56 +584,69 @@ static struct nf_hook_ops cip_arp_ops = { 


#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 *nodeidx;



	read_lock_bh(&clusterip_lock);

	if (*pos >= c->num_local_nodes)

	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;



	nodeidx = kmalloc(sizeof(unsigned int), GFP_KERNEL);

	if (!nodeidx)

	idx = kmalloc(sizeof(struct clusterip_seq_position), GFP_KERNEL);

	if (!idx)

		return ERR_PTR(-ENOMEM);



	*nodeidx = *pos;

	return nodeidx;

	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 proc_dir_entry *pde = s->private;

	struct clusterip_config *c = pde->data;

	unsigned int *nodeidx = (unsigned int *)v;

	struct clusterip_seq_position *idx = (struct clusterip_seq_position *)v;



	*pos = ++(*nodeidx);

	if (*pos >= c->num_local_nodes) {

	*pos = ++idx->pos;

	if (*pos >= idx->weight) {

		kfree(v);

		return NULL;

	}

	return nodeidx;

	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);



	read_unlock_bh(&clusterip_lock);

}



static int clusterip_seq_show(struct seq_file *s, void *v)

{

	struct proc_dir_entry *pde = s->private;

	struct clusterip_config *c = pde->data;

	unsigned int *nodeidx = (unsigned int *)v;

	struct clusterip_seq_position *idx = (struct clusterip_seq_position *)v;



	if (*nodeidx != 0) 

	if (idx->pos != 0) 

		seq_putc(s, ',');

	seq_printf(s, "%u", c->local_nodes[*nodeidx]);



	if (*nodeidx == c->num_local_nodes-1)

	seq_printf(s, "%u", idx->bit);



	if (idx->pos == idx->weight - 1)

		seq_putc(s, '\n');



	return 0;