1 /* 2 * Copyright (c) 2008-2009 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/spinlock.h> 15 #include <linux/netlink.h> 16 #include <linux/netfilter.h> 17 #include <linux/netfilter/nf_tables.h> 18 #include <net/netfilter/nf_tables.h> 19 20 static DEFINE_SPINLOCK(limit_lock); 21 22 struct nft_limit { 23 u64 tokens; 24 u64 rate; 25 u64 unit; 26 unsigned long stamp; 27 }; 28 29 static void nft_limit_eval(const struct nft_expr *expr, 30 struct nft_data data[NFT_REG_MAX + 1], 31 const struct nft_pktinfo *pkt) 32 { 33 struct nft_limit *priv = nft_expr_priv(expr); 34 35 spin_lock_bh(&limit_lock); 36 if (time_after_eq(jiffies, priv->stamp)) { 37 priv->tokens = priv->rate; 38 priv->stamp = jiffies + priv->unit * HZ; 39 } 40 41 if (priv->tokens >= 1) { 42 priv->tokens--; 43 spin_unlock_bh(&limit_lock); 44 return; 45 } 46 spin_unlock_bh(&limit_lock); 47 48 data[NFT_REG_VERDICT].verdict = NFT_BREAK; 49 } 50 51 static const struct nla_policy nft_limit_policy[NFTA_LIMIT_MAX + 1] = { 52 [NFTA_LIMIT_RATE] = { .type = NLA_U64 }, 53 [NFTA_LIMIT_UNIT] = { .type = NLA_U64 }, 54 }; 55 56 static int nft_limit_init(const struct nft_ctx *ctx, 57 const struct nft_expr *expr, 58 const struct nlattr * const tb[]) 59 { 60 struct nft_limit *priv = nft_expr_priv(expr); 61 62 if (tb[NFTA_LIMIT_RATE] == NULL || 63 tb[NFTA_LIMIT_UNIT] == NULL) 64 return -EINVAL; 65 66 priv->rate = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_RATE])); 67 priv->unit = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_UNIT])); 68 priv->stamp = jiffies + priv->unit * HZ; 69 priv->tokens = priv->rate; 70 return 0; 71 } 72 73 static int nft_limit_dump(struct sk_buff *skb, const struct nft_expr *expr) 74 { 75 const struct nft_limit *priv = nft_expr_priv(expr); 76 77 if (nla_put_be64(skb, NFTA_LIMIT_RATE, cpu_to_be64(priv->rate))) 78 goto nla_put_failure; 79 if (nla_put_be64(skb, NFTA_LIMIT_UNIT, cpu_to_be64(priv->unit))) 80 goto nla_put_failure; 81 return 0; 82 83 nla_put_failure: 84 return -1; 85 } 86 87 static struct nft_expr_type nft_limit_type; 88 static const struct nft_expr_ops nft_limit_ops = { 89 .type = &nft_limit_type, 90 .size = NFT_EXPR_SIZE(sizeof(struct nft_limit)), 91 .eval = nft_limit_eval, 92 .init = nft_limit_init, 93 .dump = nft_limit_dump, 94 }; 95 96 static struct nft_expr_type nft_limit_type __read_mostly = { 97 .name = "limit", 98 .ops = &nft_limit_ops, 99 .policy = nft_limit_policy, 100 .maxattr = NFTA_LIMIT_MAX, 101 .owner = THIS_MODULE, 102 }; 103 104 static int __init nft_limit_module_init(void) 105 { 106 return nft_register_expr(&nft_limit_type); 107 } 108 109 static void __exit nft_limit_module_exit(void) 110 { 111 nft_unregister_expr(&nft_limit_type); 112 } 113 114 module_init(nft_limit_module_init); 115 module_exit(nft_limit_module_exit); 116 117 MODULE_LICENSE("GPL"); 118 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); 119 MODULE_ALIAS_NFT_EXPR("limit"); 120