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 last; 24 u64 tokens; 25 u64 tokens_max; 26 u64 rate; 27 u64 nsecs; 28 u32 burst; 29 }; 30 31 static inline bool nft_limit_eval(struct nft_limit *limit, u64 cost) 32 { 33 u64 now, tokens; 34 s64 delta; 35 36 spin_lock_bh(&limit_lock); 37 now = ktime_get_ns(); 38 tokens = limit->tokens + now - limit->last; 39 if (tokens > limit->tokens_max) 40 tokens = limit->tokens_max; 41 42 limit->last = now; 43 delta = tokens - cost; 44 if (delta >= 0) { 45 limit->tokens = delta; 46 spin_unlock_bh(&limit_lock); 47 return false; 48 } 49 limit->tokens = tokens; 50 spin_unlock_bh(&limit_lock); 51 return true; 52 } 53 54 static int nft_limit_init(struct nft_limit *limit, 55 const struct nlattr * const tb[]) 56 { 57 u64 unit; 58 59 if (tb[NFTA_LIMIT_RATE] == NULL || 60 tb[NFTA_LIMIT_UNIT] == NULL) 61 return -EINVAL; 62 63 limit->rate = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_RATE])); 64 unit = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_UNIT])); 65 limit->nsecs = unit * NSEC_PER_SEC; 66 if (limit->rate == 0 || limit->nsecs < unit) 67 return -EOVERFLOW; 68 limit->tokens = limit->tokens_max = limit->nsecs; 69 70 if (tb[NFTA_LIMIT_BURST]) { 71 u64 rate; 72 73 limit->burst = ntohl(nla_get_be32(tb[NFTA_LIMIT_BURST])); 74 75 rate = limit->rate + limit->burst; 76 if (rate < limit->rate) 77 return -EOVERFLOW; 78 79 limit->rate = rate; 80 } 81 limit->last = ktime_get_ns(); 82 83 return 0; 84 } 85 86 static int nft_limit_dump(struct sk_buff *skb, const struct nft_limit *limit, 87 enum nft_limit_type type) 88 { 89 u64 secs = div_u64(limit->nsecs, NSEC_PER_SEC); 90 u64 rate = limit->rate - limit->burst; 91 92 if (nla_put_be64(skb, NFTA_LIMIT_RATE, cpu_to_be64(rate)) || 93 nla_put_be64(skb, NFTA_LIMIT_UNIT, cpu_to_be64(secs)) || 94 nla_put_be32(skb, NFTA_LIMIT_BURST, htonl(limit->burst)) || 95 nla_put_be32(skb, NFTA_LIMIT_TYPE, htonl(type))) 96 goto nla_put_failure; 97 return 0; 98 99 nla_put_failure: 100 return -1; 101 } 102 103 struct nft_limit_pkts { 104 struct nft_limit limit; 105 u64 cost; 106 }; 107 108 static void nft_limit_pkts_eval(const struct nft_expr *expr, 109 struct nft_regs *regs, 110 const struct nft_pktinfo *pkt) 111 { 112 struct nft_limit_pkts *priv = nft_expr_priv(expr); 113 114 if (nft_limit_eval(&priv->limit, priv->cost)) 115 regs->verdict.code = NFT_BREAK; 116 } 117 118 static const struct nla_policy nft_limit_policy[NFTA_LIMIT_MAX + 1] = { 119 [NFTA_LIMIT_RATE] = { .type = NLA_U64 }, 120 [NFTA_LIMIT_UNIT] = { .type = NLA_U64 }, 121 [NFTA_LIMIT_BURST] = { .type = NLA_U32 }, 122 [NFTA_LIMIT_TYPE] = { .type = NLA_U32 }, 123 }; 124 125 static int nft_limit_pkts_init(const struct nft_ctx *ctx, 126 const struct nft_expr *expr, 127 const struct nlattr * const tb[]) 128 { 129 struct nft_limit_pkts *priv = nft_expr_priv(expr); 130 int err; 131 132 err = nft_limit_init(&priv->limit, tb); 133 if (err < 0) 134 return err; 135 136 priv->cost = div_u64(priv->limit.nsecs, priv->limit.rate); 137 return 0; 138 } 139 140 static int nft_limit_pkts_dump(struct sk_buff *skb, const struct nft_expr *expr) 141 { 142 const struct nft_limit_pkts *priv = nft_expr_priv(expr); 143 144 return nft_limit_dump(skb, &priv->limit, NFT_LIMIT_PKTS); 145 } 146 147 static struct nft_expr_type nft_limit_type; 148 static const struct nft_expr_ops nft_limit_pkts_ops = { 149 .type = &nft_limit_type, 150 .size = NFT_EXPR_SIZE(sizeof(struct nft_limit_pkts)), 151 .eval = nft_limit_pkts_eval, 152 .init = nft_limit_pkts_init, 153 .dump = nft_limit_pkts_dump, 154 }; 155 156 static void nft_limit_pkt_bytes_eval(const struct nft_expr *expr, 157 struct nft_regs *regs, 158 const struct nft_pktinfo *pkt) 159 { 160 struct nft_limit *priv = nft_expr_priv(expr); 161 u64 cost = div_u64(priv->nsecs * pkt->skb->len, priv->rate); 162 163 if (nft_limit_eval(priv, cost)) 164 regs->verdict.code = NFT_BREAK; 165 } 166 167 static int nft_limit_pkt_bytes_init(const struct nft_ctx *ctx, 168 const struct nft_expr *expr, 169 const struct nlattr * const tb[]) 170 { 171 struct nft_limit *priv = nft_expr_priv(expr); 172 173 return nft_limit_init(priv, tb); 174 } 175 176 static int nft_limit_pkt_bytes_dump(struct sk_buff *skb, 177 const struct nft_expr *expr) 178 { 179 const struct nft_limit *priv = nft_expr_priv(expr); 180 181 return nft_limit_dump(skb, priv, NFT_LIMIT_PKT_BYTES); 182 } 183 184 static const struct nft_expr_ops nft_limit_pkt_bytes_ops = { 185 .type = &nft_limit_type, 186 .size = NFT_EXPR_SIZE(sizeof(struct nft_limit)), 187 .eval = nft_limit_pkt_bytes_eval, 188 .init = nft_limit_pkt_bytes_init, 189 .dump = nft_limit_pkt_bytes_dump, 190 }; 191 192 static const struct nft_expr_ops * 193 nft_limit_select_ops(const struct nft_ctx *ctx, 194 const struct nlattr * const tb[]) 195 { 196 if (tb[NFTA_LIMIT_TYPE] == NULL) 197 return &nft_limit_pkts_ops; 198 199 switch (ntohl(nla_get_be32(tb[NFTA_LIMIT_TYPE]))) { 200 case NFT_LIMIT_PKTS: 201 return &nft_limit_pkts_ops; 202 case NFT_LIMIT_PKT_BYTES: 203 return &nft_limit_pkt_bytes_ops; 204 } 205 return ERR_PTR(-EOPNOTSUPP); 206 } 207 208 static struct nft_expr_type nft_limit_type __read_mostly = { 209 .name = "limit", 210 .select_ops = nft_limit_select_ops, 211 .policy = nft_limit_policy, 212 .maxattr = NFTA_LIMIT_MAX, 213 .flags = NFT_EXPR_STATEFUL, 214 .owner = THIS_MODULE, 215 }; 216 217 static int __init nft_limit_module_init(void) 218 { 219 return nft_register_expr(&nft_limit_type); 220 } 221 222 static void __exit nft_limit_module_exit(void) 223 { 224 nft_unregister_expr(&nft_limit_type); 225 } 226 227 module_init(nft_limit_module_init); 228 module_exit(nft_limit_module_exit); 229 230 MODULE_LICENSE("GPL"); 231 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); 232 MODULE_ALIAS_NFT_EXPR("limit"); 233