/* * Copyright (c) 2008-2014 Patrick McHardy * * 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. * * Development of this code funded by Astaro AG (http://www.astaro.com/) */ #include #include #include #include #include #include #include #include #include #include #include /* We target a hash table size of 4, element hint is 75% of final size */ #define NFT_HASH_ELEMENT_HINT 3 struct nft_hash_elem { struct rhash_head node; struct nft_data key; struct nft_data data[]; }; static bool nft_hash_lookup(const struct nft_set *set, const struct nft_data *key, struct nft_data *data) { struct rhashtable *priv = nft_set_priv(set); const struct nft_hash_elem *he; he = rhashtable_lookup(priv, key); if (he && set->flags & NFT_SET_MAP) nft_data_copy(data, he->data); return !!he; } static int nft_hash_insert(const struct nft_set *set, const struct nft_set_elem *elem) { struct rhashtable *priv = nft_set_priv(set); struct nft_hash_elem *he; unsigned int size; if (elem->flags != 0) return -EINVAL; size = sizeof(*he); if (set->flags & NFT_SET_MAP) size += sizeof(he->data[0]); he = kzalloc(size, GFP_KERNEL); if (he == NULL) return -ENOMEM; nft_data_copy(&he->key, &elem->key); if (set->flags & NFT_SET_MAP) nft_data_copy(he->data, &elem->data); rhashtable_insert(priv, &he->node); return 0; } static void nft_hash_elem_destroy(const struct nft_set *set, struct nft_hash_elem *he) { nft_data_uninit(&he->key, NFT_DATA_VALUE); if (set->flags & NFT_SET_MAP) nft_data_uninit(he->data, set->dtype); kfree(he); } static void nft_hash_remove(const struct nft_set *set, const struct nft_set_elem *elem) { struct rhashtable *priv = nft_set_priv(set); rhashtable_remove(priv, elem->cookie); synchronize_rcu(); kfree(elem->cookie); } struct nft_compare_arg { const struct nft_set *set; struct nft_set_elem *elem; }; static bool nft_hash_compare(void *ptr, void *arg) { struct nft_hash_elem *he = ptr; struct nft_compare_arg *x = arg; if (!nft_data_cmp(&he->key, &x->elem->key, x->set->klen)) { x->elem->cookie = he; x->elem->flags = 0; if (x->set->flags & NFT_SET_MAP) nft_data_copy(&x->elem->data, he->data); return true; } return false; } static int nft_hash_get(const struct nft_set *set, struct nft_set_elem *elem) { struct rhashtable *priv = nft_set_priv(set); struct nft_compare_arg arg = { .set = set, .elem = elem, }; if (rhashtable_lookup_compare(priv, &elem->key, &nft_hash_compare, &arg)) return 0; return -ENOENT; } static void nft_hash_walk(const struct nft_ctx *ctx, const struct nft_set *set, struct nft_set_iter *iter) { struct rhashtable *priv = nft_set_priv(set); const struct nft_hash_elem *he; struct rhashtable_iter hti; struct nft_set_elem elem; int err; err = rhashtable_walk_init(priv, &hti); iter->err = err; if (err) return; err = rhashtable_walk_start(&hti); if (err && err != -EAGAIN) { iter->err = err; goto out; } while ((he = rhashtable_walk_next(&hti))) { if (IS_ERR(he)) { err = PTR_ERR(he); if (err != -EAGAIN) { iter->err = err; goto out; } } if (iter->count < iter->skip) goto cont; memcpy(&elem.key, &he->key, sizeof(elem.key)); if (set->flags & NFT_SET_MAP) memcpy(&elem.data, he->data, sizeof(elem.data)); elem.flags = 0; iter->err = iter->fn(ctx, set, iter, &elem); if (iter->err < 0) goto out; cont: iter->count++; } out: rhashtable_walk_stop(&hti); rhashtable_walk_exit(&hti); } static unsigned int nft_hash_privsize(const struct nlattr * const nla[]) { return sizeof(struct rhashtable); } static int nft_hash_init(const struct nft_set *set, const struct nft_set_desc *desc, const struct nlattr * const tb[]) { struct rhashtable *priv = nft_set_priv(set); struct rhashtable_params params = { .nelem_hint = desc->size ? : NFT_HASH_ELEMENT_HINT, .head_offset = offsetof(struct nft_hash_elem, node), .key_offset = offsetof(struct nft_hash_elem, key), .key_len = set->klen, .hashfn = jhash, }; return rhashtable_init(priv, ¶ms); } static void nft_hash_destroy(const struct nft_set *set) { struct rhashtable *priv = nft_set_priv(set); const struct bucket_table *tbl; struct nft_hash_elem *he; struct rhash_head *pos, *next; unsigned int i; /* Stop an eventual async resizing */ priv->being_destroyed = true; mutex_lock(&priv->mutex); tbl = rht_dereference(priv->tbl, priv); for (i = 0; i < tbl->size; i++) { rht_for_each_entry_safe(he, pos, next, tbl, i, node) nft_hash_elem_destroy(set, he); } mutex_unlock(&priv->mutex); rhashtable_destroy(priv); } static bool nft_hash_estimate(const struct nft_set_desc *desc, u32 features, struct nft_set_estimate *est) { unsigned int esize; esize = sizeof(struct nft_hash_elem); if (features & NFT_SET_MAP) esize += FIELD_SIZEOF(struct nft_hash_elem, data[0]); if (desc->size) { est->size = sizeof(struct rhashtable) + roundup_pow_of_two(desc->size * 4 / 3) * sizeof(struct nft_hash_elem *) + desc->size * esize; } else { /* Resizing happens when the load drops below 30% or goes * above 75%. The average of 52.5% load (approximated by 50%) * is used for the size estimation of the hash buckets, * meaning we calculate two buckets per element. */ est->size = esize + 2 * sizeof(struct nft_hash_elem *); } est->class = NFT_SET_CLASS_O_1; return true; } static struct nft_set_ops nft_hash_ops __read_mostly = { .privsize = nft_hash_privsize, .estimate = nft_hash_estimate, .init = nft_hash_init, .destroy = nft_hash_destroy, .get = nft_hash_get, .insert = nft_hash_insert, .remove = nft_hash_remove, .lookup = nft_hash_lookup, .walk = nft_hash_walk, .features = NFT_SET_MAP, .owner = THIS_MODULE, }; static int __init nft_hash_module_init(void) { return nft_register_set(&nft_hash_ops); } static void __exit nft_hash_module_exit(void) { nft_unregister_set(&nft_hash_ops); } module_init(nft_hash_module_init); module_exit(nft_hash_module_exit); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Patrick McHardy "); MODULE_ALIAS_NFT_SET();