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 bool invert; 30 }; 31 32 static inline bool nft_limit_eval(struct nft_limit *limit, u64 cost) 33 { 34 u64 now, tokens; 35 s64 delta; 36 37 spin_lock_bh(&limit_lock); 38 now = ktime_get_ns(); 39 tokens = limit->tokens + now - limit->last; 40 if (tokens > limit->tokens_max) 41 tokens = limit->tokens_max; 42 43 limit->last = now; 44 delta = tokens - cost; 45 if (delta >= 0) { 46 limit->tokens = delta; 47 spin_unlock_bh(&limit_lock); 48 return limit->invert; 49 } 50 limit->tokens = tokens; 51 spin_unlock_bh(&limit_lock); 52 return !limit->invert; 53 } 54 55 static int nft_limit_init(struct nft_limit *limit, 56 const struct nlattr * const tb[]) 57 { 58 u64 unit; 59 60 if (tb[NFTA_LIMIT_RATE] == NULL || 61 tb[NFTA_LIMIT_UNIT] == NULL) 62 return -EINVAL; 63 64 limit->rate = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_RATE])); 65 unit = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_UNIT])); 66 limit->nsecs = unit * NSEC_PER_SEC; 67 if (limit->rate == 0 || limit->nsecs < unit) 68 return -EOVERFLOW; 69 limit->tokens = limit->tokens_max = limit->nsecs; 70 71 if (tb[NFTA_LIMIT_BURST]) { 72 u64 rate; 73 74 limit->burst = ntohl(nla_get_be32(tb[NFTA_LIMIT_BURST])); 75 76 rate = limit->rate + limit->burst; 77 if (rate < limit->rate) 78 return -EOVERFLOW; 79 80 limit->rate = rate; 81 } 82 if (tb[NFTA_LIMIT_FLAGS]) { 83 u32 flags = ntohl(nla_get_be32(tb[NFTA_LIMIT_FLAGS])); 84 85 if (flags & NFT_LIMIT_F_INV) 86 limit->invert = true; 87 } 88 limit->last = ktime_get_ns(); 89 90 return 0; 91 } 92 93 static int nft_limit_dump(struct sk_buff *skb, const struct nft_limit *limit, 94 enum nft_limit_type type) 95 { 96 u32 flags = limit->invert ? NFT_LIMIT_F_INV : 0; 97 u64 secs = div_u64(limit->nsecs, NSEC_PER_SEC); 98 u64 rate = limit->rate - limit->burst; 99 100 if (nla_put_be64(skb, NFTA_LIMIT_RATE, cpu_to_be64(rate), 101 NFTA_LIMIT_PAD) || 102 nla_put_be64(skb, NFTA_LIMIT_UNIT, cpu_to_be64(secs), 103 NFTA_LIMIT_PAD) || 104 nla_put_be32(skb, NFTA_LIMIT_BURST, htonl(limit->burst)) || 105 nla_put_be32(skb, NFTA_LIMIT_TYPE, htonl(type)) || 106 nla_put_be32(skb, NFTA_LIMIT_FLAGS, htonl(flags))) 107 goto nla_put_failure; 108 return 0; 109 110 nla_put_failure: 111 return -1; 112 } 113 114 struct nft_limit_pkts { 115 struct nft_limit limit; 116 u64 cost; 117 }; 118 119 static void nft_limit_pkts_eval(const struct nft_expr *expr, 120 struct nft_regs *regs, 121 const struct nft_pktinfo *pkt) 122 { 123 struct nft_limit_pkts *priv = nft_expr_priv(expr); 124 125 if (nft_limit_eval(&priv->limit, priv->cost)) 126 regs->verdict.code = NFT_BREAK; 127 } 128 129 static const struct nla_policy nft_limit_policy[NFTA_LIMIT_MAX + 1] = { 130 [NFTA_LIMIT_RATE] = { .type = NLA_U64 }, 131 [NFTA_LIMIT_UNIT] = { .type = NLA_U64 }, 132 [NFTA_LIMIT_BURST] = { .type = NLA_U32 }, 133 [NFTA_LIMIT_TYPE] = { .type = NLA_U32 }, 134 [NFTA_LIMIT_FLAGS] = { .type = NLA_U32 }, 135 }; 136 137 static int nft_limit_pkts_init(const struct nft_ctx *ctx, 138 const struct nft_expr *expr, 139 const struct nlattr * const tb[]) 140 { 141 struct nft_limit_pkts *priv = nft_expr_priv(expr); 142 int err; 143 144 err = nft_limit_init(&priv->limit, tb); 145 if (err < 0) 146 return err; 147 148 priv->cost = div_u64(priv->limit.nsecs, priv->limit.rate); 149 return 0; 150 } 151 152 static int nft_limit_pkts_dump(struct sk_buff *skb, const struct nft_expr *expr) 153 { 154 const struct nft_limit_pkts *priv = nft_expr_priv(expr); 155 156 return nft_limit_dump(skb, &priv->limit, NFT_LIMIT_PKTS); 157 } 158 159 static struct nft_expr_type nft_limit_type; 160 static const struct nft_expr_ops nft_limit_pkts_ops = { 161 .type = &nft_limit_type, 162 .size = NFT_EXPR_SIZE(sizeof(struct nft_limit_pkts)), 163 .eval = nft_limit_pkts_eval, 164 .init = nft_limit_pkts_init, 165 .dump = nft_limit_pkts_dump, 166 }; 167 168 static void nft_limit_pkt_bytes_eval(const struct nft_expr *expr, 169 struct nft_regs *regs, 170 const struct nft_pktinfo *pkt) 171 { 172 struct nft_limit *priv = nft_expr_priv(expr); 173 u64 cost = div_u64(priv->nsecs * pkt->skb->len, priv->rate); 174 175 if (nft_limit_eval(priv, cost)) 176 regs->verdict.code = NFT_BREAK; 177 } 178 179 static int nft_limit_pkt_bytes_init(const struct nft_ctx *ctx, 180 const struct nft_expr *expr, 181 const struct nlattr * const tb[]) 182 { 183 struct nft_limit *priv = nft_expr_priv(expr); 184 185 return nft_limit_init(priv, tb); 186 } 187 188 static int nft_limit_pkt_bytes_dump(struct sk_buff *skb, 189 const struct nft_expr *expr) 190 { 191 const struct nft_limit *priv = nft_expr_priv(expr); 192 193 return nft_limit_dump(skb, priv, NFT_LIMIT_PKT_BYTES); 194 } 195 196 static const struct nft_expr_ops nft_limit_pkt_bytes_ops = { 197 .type = &nft_limit_type, 198 .size = NFT_EXPR_SIZE(sizeof(struct nft_limit)), 199 .eval = nft_limit_pkt_bytes_eval, 200 .init = nft_limit_pkt_bytes_init, 201 .dump = nft_limit_pkt_bytes_dump, 202 }; 203 204 static const struct nft_expr_ops * 205 nft_limit_select_ops(const struct nft_ctx *ctx, 206 const struct nlattr * const tb[]) 207 { 208 if (tb[NFTA_LIMIT_TYPE] == NULL) 209 return &nft_limit_pkts_ops; 210 211 switch (ntohl(nla_get_be32(tb[NFTA_LIMIT_TYPE]))) { 212 case NFT_LIMIT_PKTS: 213 return &nft_limit_pkts_ops; 214 case NFT_LIMIT_PKT_BYTES: 215 return &nft_limit_pkt_bytes_ops; 216 } 217 return ERR_PTR(-EOPNOTSUPP); 218 } 219 220 static struct nft_expr_type nft_limit_type __read_mostly = { 221 .name = "limit", 222 .select_ops = nft_limit_select_ops, 223 .policy = nft_limit_policy, 224 .maxattr = NFTA_LIMIT_MAX, 225 .flags = NFT_EXPR_STATEFUL, 226 .owner = THIS_MODULE, 227 }; 228 229 static int __init nft_limit_module_init(void) 230 { 231 return nft_register_expr(&nft_limit_type); 232 } 233 234 static void __exit nft_limit_module_exit(void) 235 { 236 nft_unregister_expr(&nft_limit_type); 237 } 238 239 module_init(nft_limit_module_init); 240 module_exit(nft_limit_module_exit); 241 242 MODULE_LICENSE("GPL"); 243 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); 244 MODULE_ALIAS_NFT_EXPR("limit"); 245