diff --git a/include/uapi/linux/netfilter/xt_quota.h b/include/uapi/linux/netfilter/xt_quota.h index d72fd52adbba..f3ba5d9e58b6 100644 --- a/include/uapi/linux/netfilter/xt_quota.h +++ b/include/uapi/linux/netfilter/xt_quota.h @@ -15,11 +15,9 @@ struct xt_quota_info { __u32 flags; __u32 pad; __aligned_u64 quota; -#ifdef __KERNEL__ - atomic64_t counter; -#else - __aligned_u64 remain; -#endif + + /* Used internally by the kernel */ + struct xt_quota_priv *master; }; #endif /* _XT_QUOTA_H */ diff --git a/net/netfilter/xt_quota.c b/net/netfilter/xt_quota.c index fceae245eb03..10d61a6eed71 100644 --- a/net/netfilter/xt_quota.c +++ b/net/netfilter/xt_quota.c @@ -11,6 +11,11 @@ #include #include +struct xt_quota_priv { + spinlock_t lock; + uint64_t quota; +}; + MODULE_LICENSE("GPL"); MODULE_AUTHOR("Sam Johnston "); MODULE_DESCRIPTION("Xtables: countdown quota match"); @@ -21,48 +26,54 @@ static bool quota_mt(const struct sk_buff *skb, struct xt_action_param *par) { struct xt_quota_info *q = (void *)par->matchinfo; - u64 current_count = atomic64_read(&q->counter); + struct xt_quota_priv *priv = q->master; bool ret = q->flags & XT_QUOTA_INVERT; - u64 old_count, new_count; - do { - if (current_count == 1) - return ret; - if (current_count <= skb->len) { - atomic64_set(&q->counter, 1); - return ret; - } - old_count = current_count; - new_count = current_count - skb->len; - current_count = atomic64_cmpxchg(&q->counter, old_count, - new_count); - } while (current_count != old_count); - return !ret; + spin_lock_bh(&priv->lock); + if (priv->quota >= skb->len) { + priv->quota -= skb->len; + ret = !ret; + } else { + /* we do not allow even small packets from now on */ + priv->quota = 0; + } + spin_unlock_bh(&priv->lock); + + return ret; } static int quota_mt_check(const struct xt_mtchk_param *par) { struct xt_quota_info *q = par->matchinfo; - BUILD_BUG_ON(sizeof(atomic64_t) != sizeof(__u64)); - if (q->flags & ~XT_QUOTA_MASK) return -EINVAL; - if (atomic64_read(&q->counter) > q->quota + 1) - return -ERANGE; - if (atomic64_read(&q->counter) == 0) - atomic64_set(&q->counter, q->quota + 1); + q->master = kmalloc(sizeof(*q->master), GFP_KERNEL); + if (q->master == NULL) + return -ENOMEM; + + spin_lock_init(&q->master->lock); + q->master->quota = q->quota; return 0; } +static void quota_mt_destroy(const struct xt_mtdtor_param *par) +{ + const struct xt_quota_info *q = par->matchinfo; + + kfree(q->master); +} + static struct xt_match quota_mt_reg __read_mostly = { .name = "quota", .revision = 0, .family = NFPROTO_UNSPEC, .match = quota_mt, .checkentry = quota_mt_check, + .destroy = quota_mt_destroy, .matchsize = sizeof(struct xt_quota_info), + .usersize = offsetof(struct xt_quota_info, master), .me = THIS_MODULE, };