[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: KOVACS Krisztian <hidden@balabit.hu>
Signed-off-by: Harald Welte <laforge@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/netfilter/ipt_CLUSTERIP.c b/net/ipv4/netfilter/ipt_CLUSTERIP.c
index adbf4d7..9bcb398 100644
--- a/net/ipv4/netfilter/ipt_CLUSTERIP.c
+++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c
@@ -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 @@
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 @@
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 @@
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 @@
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 @@
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);
- return 1;
- }
- }
+ /* 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);
- return 0;
- }
- }
+ if (test_and_clear_bit(nodenum - 1, &c->local_nodes))
+ return 0;
- write_unlock_bh(&clusterip_lock);
return 1;
}
@@ -315,25 +299,7 @@
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 @@
#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;
+ unsigned int weight;
+ u_int32_t local_nodes;
+ struct clusterip_seq_position *idx;
- read_lock_bh(&clusterip_lock);
- if (*pos >= c->num_local_nodes)
+ /* 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;