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xt_quota2: allow for multiple rules to share one counter

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This commit is contained in:
Jan Engelhardt
2008-06-09 14:07:33 +02:00
parent a1e915a984
commit e987e2118c
2 changed files with 111 additions and 43 deletions
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143
extensions/xt_quota2.c
View File

@@ -3,15 +3,28 @@
*
* Sam Johnston <samj@samj.net>
*/
#include <linux/list.h>
#include <linux/proc_fs.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <asm/atomic.h>
#include <linux/netfilter/x_tables.h>
#include "xt_quota2.h"
#include "compat_xtables.h"
static DEFINE_SPINLOCK(quota2_lock);
struct quota_counter {
u_int64_t quota;
spinlock_t lock;
struct list_head list;
atomic_t ref;
char name[XT_QUOTA_COUNTER_NAME_LENGTH];
struct proc_dir_entry *procfs_entry;
};
static LIST_HEAD(counter_list);
static DEFINE_SPINLOCK(counter_list_lock);
static struct proc_dir_entry *proc_xt_quota;
static unsigned int quota_list_perms = S_IRUGO | S_IWUSR;
static unsigned int quota_list_uid = 0;
@@ -23,15 +36,19 @@ module_param_named(gid, quota_list_gid, uint, S_IRUGO | S_IWUSR);
static int quota_proc_read(char *page, char **start, off_t offset,
int count, int *eof, void *data)
{
const struct xt_quota_mtinfo2 *q = data;
struct quota_counter *e = data;
int ret;
return snprintf(page, PAGE_SIZE, "%llu\n", q->quota);
spin_lock_bh(&e->lock);
ret = snprintf(page, PAGE_SIZE, "%llu\n", e->quota);
spin_unlock_bh(&e->lock);
return ret;
}
static int quota_proc_write(struct file *file, const char __user *input,
unsigned long size, void *data)
{
struct xt_quota_mtinfo2 *q = data;
struct quota_counter *e = data;
char buf[sizeof("18446744073709551616")];
if (size > sizeof(buf))
@@ -40,10 +57,61 @@ static int quota_proc_write(struct file *file, const char __user *input,
return -EFAULT;
buf[sizeof(buf)-1] = '\0';
q->quota = simple_strtoul(buf, NULL, 0);
spin_lock_bh(&e->lock);
e->quota = simple_strtoul(buf, NULL, 0);
spin_unlock_bh(&e->lock);
return size;
}
/**
* q2_get_counter - get ref to counter or create new
* @name: name of counter
*/
static struct quota_counter *q2_get_counter(const struct xt_quota_mtinfo2 *q)
{
struct proc_dir_entry *p;
struct quota_counter *e;
spin_lock_bh(&counter_list_lock);
list_for_each_entry(e, &counter_list, list) {
if (strcmp(e->name, q->name) == 0) {
atomic_inc(&e->ref);
spin_unlock_bh(&counter_list_lock);
return e;
}
}
e = kmalloc(sizeof(struct quota_counter), GFP_KERNEL);
if (e == NULL)
goto out;
e->quota = q->quota;
spin_lock_init(&e->lock);
INIT_LIST_HEAD(&e->list);
atomic_set(&e->ref, 1);
strncpy(e->name, q->name, sizeof(e->name));
p = e->procfs_entry = create_proc_entry(e->name, quota_list_perms,
proc_xt_quota);
if (p == NULL || IS_ERR(p))
goto out;
p->owner = THIS_MODULE;
p->data = e;
p->read_proc = quota_proc_read;
p->write_proc = quota_proc_write;
p->uid = quota_list_uid;
p->gid = quota_list_gid;
list_add_tail(&e->list, &counter_list);
spin_unlock_bh(&counter_list_lock);
return e;
out:
spin_unlock_bh(&counter_list_lock);
kfree(e);
return NULL;
}
static bool
quota_mt2_check(const char *tablename, const void *entry,
const struct xt_match *match, void *matchinfo,
@@ -53,41 +121,38 @@ quota_mt2_check(const char *tablename, const void *entry,
if (q->flags & ~XT_QUOTA_MASK)
return false;
q->name[sizeof(q->name)-1] = '\0';
if (*q->name == '\0') {
q->procfs_entry = NULL;
} else if (*q->name == '.' || strchr(q->name, '/') != NULL) {
q->name[sizeof(q->name)-1] = '\0';
if (*q->name == '\0' || *q->name == '.' ||
strchr(q->name, '/') != NULL) {
printk(KERN_ERR "xt_quota.2: illegal name\n");
return false;
} else {
struct proc_dir_entry *p =
create_proc_entry(q->name, quota_list_perms,
proc_xt_quota);
if (p == NULL || IS_ERR(p)) {
printk(KERN_ERR "xt_quota.2: create_proc_entry failed with %ld\n", PTR_ERR(p));
return false;
}
q->procfs_entry = p;
p->owner = THIS_MODULE;
p->data = q;
p->read_proc = quota_proc_read;
p->write_proc = quota_proc_write;
p->uid = quota_list_uid;
p->gid = quota_list_gid;
}
/* For SMP, we only want to use one set of counters. */
q->master = q;
q->master = q2_get_counter(q);
if (q->master == NULL) {
printk(KERN_ERR "xt_quota.2: memory alloc failure\n");
return false;
}
return true;
}
static void quota_mt2_destroy(const struct xt_match *match, void *matchinfo)
{
struct xt_quota_mtinfo2 *q = matchinfo;
struct quota_counter *e = q->master;
if (q->procfs_entry != NULL)
remove_proc_entry(q->name, proc_xt_quota);
spin_lock_bh(&counter_list_lock);
if (!atomic_dec_and_test(&e->ref)) {
spin_unlock_bh(&counter_list_lock);
return;
}
list_del(&e->list);
spin_unlock_bh(&counter_list_lock);
remove_proc_entry(e->name, proc_xt_quota);
kfree(e);
}
static bool
@@ -96,25 +161,27 @@ quota_mt2(const struct sk_buff *skb, const struct net_device *in,
const void *matchinfo, int offset, unsigned int protoff,
bool *hotdrop)
{
struct xt_quota_mtinfo2 *q =
((const struct xt_quota_mtinfo2 *)matchinfo)->master;
struct xt_quota_mtinfo2 *q = (void *)matchinfo;
struct quota_counter *e = q->master;
bool ret = q->flags & XT_QUOTA_INVERT;
if (q->flags & XT_QUOTA_GROW) {
spin_lock_bh(&quota2_lock);
q->quota += skb->len;
spin_unlock_bh(&quota2_lock);
spin_lock_bh(&e->lock);
e->quota += skb->len;
q->quota = e->quota;
spin_unlock_bh(&e->lock);
ret = true;
} else {
spin_lock_bh(&quota2_lock);
if (q->quota >= skb->len) {
q->quota -= skb->len;
spin_lock_bh(&e->lock);
if (e->quota >= skb->len) {
e->quota -= skb->len;
ret = !ret;
} else {
/* we do not allow even small packets from now on */
q->quota = 0;
e->quota = 0;
}
spin_unlock_bh(&quota2_lock);
q->quota = e->quota;
spin_unlock_bh(&e->lock);
}
return ret;

11
extensions/xt_quota2.h
View File

@@ -5,20 +5,21 @@ enum xt_quota_flags {
XT_QUOTA_INVERT = 0x1,
XT_QUOTA_GROW = 0x2,
XT_QUOTA_MASK = 0x3,
XT_QUOTA_COUNTER_NAME_LENGTH = 31,
};
struct quota_sysfs_entry;
struct quota_counter;
struct xt_quota_mtinfo2 {
char name[31];
char name[XT_QUOTA_COUNTER_NAME_LENGTH];
u_int8_t flags;
/* Comparison-invariant section */
/* Comparison-invariant */
aligned_u64 quota;
/* Used internally by the kernel */
struct xt_quota_mtinfo2 *master __attribute__((aligned(8)));
void *procfs_entry __attribute__((aligned(8)));
struct quota_counter *master __attribute__((aligned(8)));
};
#endif /* _XT_QUOTA_H */