1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (c) 2016 Pablo Neira Ayuso <pablo@netfilter.org> 4 */ 5 6 #include <linux/kernel.h> 7 #include <linux/init.h> 8 #include <linux/module.h> 9 #include <linux/atomic.h> 10 #include <linux/netlink.h> 11 #include <linux/netfilter.h> 12 #include <linux/netfilter/nf_tables.h> 13 #include <net/netfilter/nf_tables.h> 14 15 struct nft_quota { 16 atomic64_t quota; 17 unsigned long flags; 18 atomic64_t consumed; 19 }; 20 21 static inline bool nft_overquota(struct nft_quota *priv, 22 const struct sk_buff *skb) 23 { 24 return atomic64_add_return(skb->len, &priv->consumed) >= 25 atomic64_read(&priv->quota); 26 } 27 28 static inline bool nft_quota_invert(struct nft_quota *priv) 29 { 30 return priv->flags & NFT_QUOTA_F_INV; 31 } 32 33 static inline void nft_quota_do_eval(struct nft_quota *priv, 34 struct nft_regs *regs, 35 const struct nft_pktinfo *pkt) 36 { 37 if (nft_overquota(priv, pkt->skb) ^ nft_quota_invert(priv)) 38 regs->verdict.code = NFT_BREAK; 39 } 40 41 static const struct nla_policy nft_quota_policy[NFTA_QUOTA_MAX + 1] = { 42 [NFTA_QUOTA_BYTES] = { .type = NLA_U64 }, 43 [NFTA_QUOTA_FLAGS] = { .type = NLA_U32 }, 44 [NFTA_QUOTA_CONSUMED] = { .type = NLA_U64 }, 45 }; 46 47 #define NFT_QUOTA_DEPLETED_BIT 1 /* From NFT_QUOTA_F_DEPLETED. */ 48 49 static void nft_quota_obj_eval(struct nft_object *obj, 50 struct nft_regs *regs, 51 const struct nft_pktinfo *pkt) 52 { 53 struct nft_quota *priv = nft_obj_data(obj); 54 bool overquota; 55 56 overquota = nft_overquota(priv, pkt->skb); 57 if (overquota ^ nft_quota_invert(priv)) 58 regs->verdict.code = NFT_BREAK; 59 60 if (overquota && 61 !test_and_set_bit(NFT_QUOTA_DEPLETED_BIT, &priv->flags)) 62 nft_obj_notify(nft_net(pkt), obj->key.table, obj, 0, 0, 63 NFT_MSG_NEWOBJ, nft_pf(pkt), 0, GFP_ATOMIC); 64 } 65 66 static int nft_quota_do_init(const struct nlattr * const tb[], 67 struct nft_quota *priv) 68 { 69 unsigned long flags = 0; 70 u64 quota, consumed = 0; 71 72 if (!tb[NFTA_QUOTA_BYTES]) 73 return -EINVAL; 74 75 quota = be64_to_cpu(nla_get_be64(tb[NFTA_QUOTA_BYTES])); 76 if (quota > S64_MAX) 77 return -EOVERFLOW; 78 79 if (tb[NFTA_QUOTA_CONSUMED]) { 80 consumed = be64_to_cpu(nla_get_be64(tb[NFTA_QUOTA_CONSUMED])); 81 if (consumed > quota) 82 return -EINVAL; 83 } 84 85 if (tb[NFTA_QUOTA_FLAGS]) { 86 flags = ntohl(nla_get_be32(tb[NFTA_QUOTA_FLAGS])); 87 if (flags & ~NFT_QUOTA_F_INV) 88 return -EINVAL; 89 if (flags & NFT_QUOTA_F_DEPLETED) 90 return -EOPNOTSUPP; 91 } 92 93 atomic64_set(&priv->quota, quota); 94 priv->flags = flags; 95 atomic64_set(&priv->consumed, consumed); 96 97 return 0; 98 } 99 100 static int nft_quota_obj_init(const struct nft_ctx *ctx, 101 const struct nlattr * const tb[], 102 struct nft_object *obj) 103 { 104 struct nft_quota *priv = nft_obj_data(obj); 105 106 return nft_quota_do_init(tb, priv); 107 } 108 109 static void nft_quota_obj_update(struct nft_object *obj, 110 struct nft_object *newobj) 111 { 112 struct nft_quota *newpriv = nft_obj_data(newobj); 113 struct nft_quota *priv = nft_obj_data(obj); 114 u64 newquota; 115 116 newquota = atomic64_read(&newpriv->quota); 117 atomic64_set(&priv->quota, newquota); 118 priv->flags = newpriv->flags; 119 } 120 121 static int nft_quota_do_dump(struct sk_buff *skb, struct nft_quota *priv, 122 bool reset) 123 { 124 u64 consumed, consumed_cap, quota; 125 u32 flags = priv->flags; 126 127 /* Since we inconditionally increment consumed quota for each packet 128 * that we see, don't go over the quota boundary in what we send to 129 * userspace. 130 */ 131 consumed = atomic64_read(&priv->consumed); 132 quota = atomic64_read(&priv->quota); 133 if (consumed >= quota) { 134 consumed_cap = quota; 135 flags |= NFT_QUOTA_F_DEPLETED; 136 } else { 137 consumed_cap = consumed; 138 } 139 140 if (nla_put_be64(skb, NFTA_QUOTA_BYTES, cpu_to_be64(quota), 141 NFTA_QUOTA_PAD) || 142 nla_put_be64(skb, NFTA_QUOTA_CONSUMED, cpu_to_be64(consumed_cap), 143 NFTA_QUOTA_PAD) || 144 nla_put_be32(skb, NFTA_QUOTA_FLAGS, htonl(flags))) 145 goto nla_put_failure; 146 147 if (reset) { 148 atomic64_sub(consumed, &priv->consumed); 149 clear_bit(NFT_QUOTA_DEPLETED_BIT, &priv->flags); 150 } 151 return 0; 152 153 nla_put_failure: 154 return -1; 155 } 156 157 static int nft_quota_obj_dump(struct sk_buff *skb, struct nft_object *obj, 158 bool reset) 159 { 160 struct nft_quota *priv = nft_obj_data(obj); 161 162 return nft_quota_do_dump(skb, priv, reset); 163 } 164 165 static struct nft_object_type nft_quota_obj_type; 166 static const struct nft_object_ops nft_quota_obj_ops = { 167 .type = &nft_quota_obj_type, 168 .size = sizeof(struct nft_quota), 169 .init = nft_quota_obj_init, 170 .eval = nft_quota_obj_eval, 171 .dump = nft_quota_obj_dump, 172 .update = nft_quota_obj_update, 173 }; 174 175 static struct nft_object_type nft_quota_obj_type __read_mostly = { 176 .type = NFT_OBJECT_QUOTA, 177 .ops = &nft_quota_obj_ops, 178 .maxattr = NFTA_QUOTA_MAX, 179 .policy = nft_quota_policy, 180 .owner = THIS_MODULE, 181 }; 182 183 static void nft_quota_eval(const struct nft_expr *expr, 184 struct nft_regs *regs, 185 const struct nft_pktinfo *pkt) 186 { 187 struct nft_quota *priv = nft_expr_priv(expr); 188 189 nft_quota_do_eval(priv, regs, pkt); 190 } 191 192 static int nft_quota_init(const struct nft_ctx *ctx, 193 const struct nft_expr *expr, 194 const struct nlattr * const tb[]) 195 { 196 struct nft_quota *priv = nft_expr_priv(expr); 197 198 return nft_quota_do_init(tb, priv); 199 } 200 201 static int nft_quota_dump(struct sk_buff *skb, const struct nft_expr *expr) 202 { 203 struct nft_quota *priv = nft_expr_priv(expr); 204 205 return nft_quota_do_dump(skb, priv, false); 206 } 207 208 static struct nft_expr_type nft_quota_type; 209 static const struct nft_expr_ops nft_quota_ops = { 210 .type = &nft_quota_type, 211 .size = NFT_EXPR_SIZE(sizeof(struct nft_quota)), 212 .eval = nft_quota_eval, 213 .init = nft_quota_init, 214 .dump = nft_quota_dump, 215 }; 216 217 static struct nft_expr_type nft_quota_type __read_mostly = { 218 .name = "quota", 219 .ops = &nft_quota_ops, 220 .policy = nft_quota_policy, 221 .maxattr = NFTA_QUOTA_MAX, 222 .flags = NFT_EXPR_STATEFUL, 223 .owner = THIS_MODULE, 224 }; 225 226 static int __init nft_quota_module_init(void) 227 { 228 int err; 229 230 err = nft_register_obj(&nft_quota_obj_type); 231 if (err < 0) 232 return err; 233 234 err = nft_register_expr(&nft_quota_type); 235 if (err < 0) 236 goto err1; 237 238 return 0; 239 err1: 240 nft_unregister_obj(&nft_quota_obj_type); 241 return err; 242 } 243 244 static void __exit nft_quota_module_exit(void) 245 { 246 nft_unregister_expr(&nft_quota_type); 247 nft_unregister_obj(&nft_quota_obj_type); 248 } 249 250 module_init(nft_quota_module_init); 251 module_exit(nft_quota_module_exit); 252 253 MODULE_LICENSE("GPL"); 254 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>"); 255 MODULE_ALIAS_NFT_EXPR("quota"); 256 MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_QUOTA); 257 MODULE_DESCRIPTION("Netfilter nftables quota module"); 258