1 /* 2 * Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net> 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 * 8 * Development of this code funded by Astaro AG (http://www.astaro.com/) 9 */ 10 11 #include <linux/kernel.h> 12 #include <linux/init.h> 13 #include <linux/module.h> 14 #include <linux/list.h> 15 #include <linux/log2.h> 16 #include <linux/jhash.h> 17 #include <linux/netlink.h> 18 #include <linux/rhashtable.h> 19 #include <linux/netfilter.h> 20 #include <linux/netfilter/nf_tables.h> 21 #include <net/netfilter/nf_tables.h> 22 23 /* We target a hash table size of 4, element hint is 75% of final size */ 24 #define NFT_HASH_ELEMENT_HINT 3 25 26 struct nft_hash_elem { 27 struct rhash_head node; 28 struct nft_data key; 29 struct nft_data data[]; 30 }; 31 32 static bool nft_hash_lookup(const struct nft_set *set, 33 const struct nft_data *key, 34 struct nft_data *data) 35 { 36 const struct rhashtable *priv = nft_set_priv(set); 37 const struct nft_hash_elem *he; 38 39 he = rhashtable_lookup(priv, key); 40 if (he && set->flags & NFT_SET_MAP) 41 nft_data_copy(data, he->data); 42 43 return !!he; 44 } 45 46 static int nft_hash_insert(const struct nft_set *set, 47 const struct nft_set_elem *elem) 48 { 49 struct rhashtable *priv = nft_set_priv(set); 50 struct nft_hash_elem *he; 51 unsigned int size; 52 53 if (elem->flags != 0) 54 return -EINVAL; 55 56 size = sizeof(*he); 57 if (set->flags & NFT_SET_MAP) 58 size += sizeof(he->data[0]); 59 60 he = kzalloc(size, GFP_KERNEL); 61 if (he == NULL) 62 return -ENOMEM; 63 64 nft_data_copy(&he->key, &elem->key); 65 if (set->flags & NFT_SET_MAP) 66 nft_data_copy(he->data, &elem->data); 67 68 rhashtable_insert(priv, &he->node, GFP_KERNEL); 69 70 return 0; 71 } 72 73 static void nft_hash_elem_destroy(const struct nft_set *set, 74 struct nft_hash_elem *he) 75 { 76 nft_data_uninit(&he->key, NFT_DATA_VALUE); 77 if (set->flags & NFT_SET_MAP) 78 nft_data_uninit(he->data, set->dtype); 79 kfree(he); 80 } 81 82 static void nft_hash_remove(const struct nft_set *set, 83 const struct nft_set_elem *elem) 84 { 85 struct rhashtable *priv = nft_set_priv(set); 86 struct rhash_head *he, __rcu **pprev; 87 88 pprev = elem->cookie; 89 he = rht_dereference((*pprev), priv); 90 91 rhashtable_remove_pprev(priv, he, pprev, GFP_KERNEL); 92 93 synchronize_rcu(); 94 kfree(he); 95 } 96 97 static int nft_hash_get(const struct nft_set *set, struct nft_set_elem *elem) 98 { 99 const struct rhashtable *priv = nft_set_priv(set); 100 const struct bucket_table *tbl = rht_dereference_rcu(priv->tbl, priv); 101 struct rhash_head __rcu * const *pprev; 102 struct nft_hash_elem *he; 103 u32 h; 104 105 h = rhashtable_hashfn(priv, &elem->key, set->klen); 106 pprev = &tbl->buckets[h]; 107 rht_for_each_entry_rcu(he, tbl->buckets[h], node) { 108 if (nft_data_cmp(&he->key, &elem->key, set->klen)) { 109 pprev = &he->node.next; 110 continue; 111 } 112 113 elem->cookie = (void *)pprev; 114 elem->flags = 0; 115 if (set->flags & NFT_SET_MAP) 116 nft_data_copy(&elem->data, he->data); 117 return 0; 118 } 119 return -ENOENT; 120 } 121 122 static void nft_hash_walk(const struct nft_ctx *ctx, const struct nft_set *set, 123 struct nft_set_iter *iter) 124 { 125 const struct rhashtable *priv = nft_set_priv(set); 126 const struct bucket_table *tbl; 127 const struct nft_hash_elem *he; 128 struct nft_set_elem elem; 129 unsigned int i; 130 131 tbl = rht_dereference_rcu(priv->tbl, priv); 132 for (i = 0; i < tbl->size; i++) { 133 rht_for_each_entry_rcu(he, tbl->buckets[i], node) { 134 if (iter->count < iter->skip) 135 goto cont; 136 137 memcpy(&elem.key, &he->key, sizeof(elem.key)); 138 if (set->flags & NFT_SET_MAP) 139 memcpy(&elem.data, he->data, sizeof(elem.data)); 140 elem.flags = 0; 141 142 iter->err = iter->fn(ctx, set, iter, &elem); 143 if (iter->err < 0) 144 return; 145 cont: 146 iter->count++; 147 } 148 } 149 } 150 151 static unsigned int nft_hash_privsize(const struct nlattr * const nla[]) 152 { 153 return sizeof(struct rhashtable); 154 } 155 156 static int lockdep_nfnl_lock_is_held(void) 157 { 158 return lockdep_nfnl_is_held(NFNL_SUBSYS_NFTABLES); 159 } 160 161 static int nft_hash_init(const struct nft_set *set, 162 const struct nft_set_desc *desc, 163 const struct nlattr * const tb[]) 164 { 165 struct rhashtable *priv = nft_set_priv(set); 166 struct rhashtable_params params = { 167 .nelem_hint = desc->size ? : NFT_HASH_ELEMENT_HINT, 168 .head_offset = offsetof(struct nft_hash_elem, node), 169 .key_offset = offsetof(struct nft_hash_elem, key), 170 .key_len = set->klen, 171 .hashfn = jhash, 172 .grow_decision = rht_grow_above_75, 173 .shrink_decision = rht_shrink_below_30, 174 .mutex_is_held = lockdep_nfnl_lock_is_held, 175 }; 176 177 return rhashtable_init(priv, ¶ms); 178 } 179 180 static void nft_hash_destroy(const struct nft_set *set) 181 { 182 const struct rhashtable *priv = nft_set_priv(set); 183 const struct bucket_table *tbl; 184 struct nft_hash_elem *he, *next; 185 unsigned int i; 186 187 tbl = rht_dereference(priv->tbl, priv); 188 for (i = 0; i < tbl->size; i++) 189 rht_for_each_entry_safe(he, next, tbl->buckets[i], priv, node) 190 nft_hash_elem_destroy(set, he); 191 192 rhashtable_destroy(priv); 193 } 194 195 static bool nft_hash_estimate(const struct nft_set_desc *desc, u32 features, 196 struct nft_set_estimate *est) 197 { 198 unsigned int esize; 199 200 esize = sizeof(struct nft_hash_elem); 201 if (features & NFT_SET_MAP) 202 esize += FIELD_SIZEOF(struct nft_hash_elem, data[0]); 203 204 if (desc->size) { 205 est->size = sizeof(struct rhashtable) + 206 roundup_pow_of_two(desc->size * 4 / 3) * 207 sizeof(struct nft_hash_elem *) + 208 desc->size * esize; 209 } else { 210 /* Resizing happens when the load drops below 30% or goes 211 * above 75%. The average of 52.5% load (approximated by 50%) 212 * is used for the size estimation of the hash buckets, 213 * meaning we calculate two buckets per element. 214 */ 215 est->size = esize + 2 * sizeof(struct nft_hash_elem *); 216 } 217 218 est->class = NFT_SET_CLASS_O_1; 219 220 return true; 221 } 222 223 static struct nft_set_ops nft_hash_ops __read_mostly = { 224 .privsize = nft_hash_privsize, 225 .estimate = nft_hash_estimate, 226 .init = nft_hash_init, 227 .destroy = nft_hash_destroy, 228 .get = nft_hash_get, 229 .insert = nft_hash_insert, 230 .remove = nft_hash_remove, 231 .lookup = nft_hash_lookup, 232 .walk = nft_hash_walk, 233 .features = NFT_SET_MAP, 234 .owner = THIS_MODULE, 235 }; 236 237 static int __init nft_hash_module_init(void) 238 { 239 return nft_register_set(&nft_hash_ops); 240 } 241 242 static void __exit nft_hash_module_exit(void) 243 { 244 nft_unregister_set(&nft_hash_ops); 245 } 246 247 module_init(nft_hash_module_init); 248 module_exit(nft_hash_module_exit); 249 250 MODULE_LICENSE("GPL"); 251 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); 252 MODULE_ALIAS_NFT_SET(); 253