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 nla_put_be64(skb, NFTA_LIMIT_UNIT, cpu_to_be64(secs)) || 102 nla_put_be32(skb, NFTA_LIMIT_BURST, htonl(limit->burst)) || 103 nla_put_be32(skb, NFTA_LIMIT_TYPE, htonl(type)) || 104 nla_put_be32(skb, NFTA_LIMIT_FLAGS, htonl(flags))) 105 goto nla_put_failure; 106 return 0; 107 108 nla_put_failure: 109 return -1; 110 } 111 112 struct nft_limit_pkts { 113 struct nft_limit limit; 114 u64 cost; 115 }; 116 117 static void nft_limit_pkts_eval(const struct nft_expr *expr, 118 struct nft_regs *regs, 119 const struct nft_pktinfo *pkt) 120 { 121 struct nft_limit_pkts *priv = nft_expr_priv(expr); 122 123 if (nft_limit_eval(&priv->limit, priv->cost)) 124 regs->verdict.code = NFT_BREAK; 125 } 126 127 static const struct nla_policy nft_limit_policy[NFTA_LIMIT_MAX + 1] = { 128 [NFTA_LIMIT_RATE] = { .type = NLA_U64 }, 129 [NFTA_LIMIT_UNIT] = { .type = NLA_U64 }, 130 [NFTA_LIMIT_BURST] = { .type = NLA_U32 }, 131 [NFTA_LIMIT_TYPE] = { .type = NLA_U32 }, 132 [NFTA_LIMIT_FLAGS] = { .type = NLA_U32 }, 133 }; 134 135 static int nft_limit_pkts_init(const struct nft_ctx *ctx, 136 const struct nft_expr *expr, 137 const struct nlattr * const tb[]) 138 { 139 struct nft_limit_pkts *priv = nft_expr_priv(expr); 140 int err; 141 142 err = nft_limit_init(&priv->limit, tb); 143 if (err < 0) 144 return err; 145 146 priv->cost = div_u64(priv->limit.nsecs, priv->limit.rate); 147 return 0; 148 } 149 150 static int nft_limit_pkts_dump(struct sk_buff *skb, const struct nft_expr *expr) 151 { 152 const struct nft_limit_pkts *priv = nft_expr_priv(expr); 153 154 return nft_limit_dump(skb, &priv->limit, NFT_LIMIT_PKTS); 155 } 156 157 static struct nft_expr_type nft_limit_type; 158 static const struct nft_expr_ops nft_limit_pkts_ops = { 159 .type = &nft_limit_type, 160 .size = NFT_EXPR_SIZE(sizeof(struct nft_limit_pkts)), 161 .eval = nft_limit_pkts_eval, 162 .init = nft_limit_pkts_init, 163 .dump = nft_limit_pkts_dump, 164 }; 165 166 static void nft_limit_pkt_bytes_eval(const struct nft_expr *expr, 167 struct nft_regs *regs, 168 const struct nft_pktinfo *pkt) 169 { 170 struct nft_limit *priv = nft_expr_priv(expr); 171 u64 cost = div_u64(priv->nsecs * pkt->skb->len, priv->rate); 172 173 if (nft_limit_eval(priv, cost)) 174 regs->verdict.code = NFT_BREAK; 175 } 176 177 static int nft_limit_pkt_bytes_init(const struct nft_ctx *ctx, 178 const struct nft_expr *expr, 179 const struct nlattr * const tb[]) 180 { 181 struct nft_limit *priv = nft_expr_priv(expr); 182 183 return nft_limit_init(priv, tb); 184 } 185 186 static int nft_limit_pkt_bytes_dump(struct sk_buff *skb, 187 const struct nft_expr *expr) 188 { 189 const struct nft_limit *priv = nft_expr_priv(expr); 190 191 return nft_limit_dump(skb, priv, NFT_LIMIT_PKT_BYTES); 192 } 193 194 static const struct nft_expr_ops nft_limit_pkt_bytes_ops = { 195 .type = &nft_limit_type, 196 .size = NFT_EXPR_SIZE(sizeof(struct nft_limit)), 197 .eval = nft_limit_pkt_bytes_eval, 198 .init = nft_limit_pkt_bytes_init, 199 .dump = nft_limit_pkt_bytes_dump, 200 }; 201 202 static const struct nft_expr_ops * 203 nft_limit_select_ops(const struct nft_ctx *ctx, 204 const struct nlattr * const tb[]) 205 { 206 if (tb[NFTA_LIMIT_TYPE] == NULL) 207 return &nft_limit_pkts_ops; 208 209 switch (ntohl(nla_get_be32(tb[NFTA_LIMIT_TYPE]))) { 210 case NFT_LIMIT_PKTS: 211 return &nft_limit_pkts_ops; 212 case NFT_LIMIT_PKT_BYTES: 213 return &nft_limit_pkt_bytes_ops; 214 } 215 return ERR_PTR(-EOPNOTSUPP); 216 } 217 218 static struct nft_expr_type nft_limit_type __read_mostly = { 219 .name = "limit", 220 .select_ops = nft_limit_select_ops, 221 .policy = nft_limit_policy, 222 .maxattr = NFTA_LIMIT_MAX, 223 .flags = NFT_EXPR_STATEFUL, 224 .owner = THIS_MODULE, 225 }; 226 227 static int __init nft_limit_module_init(void) 228 { 229 return nft_register_expr(&nft_limit_type); 230 } 231 232 static void __exit nft_limit_module_exit(void) 233 { 234 nft_unregister_expr(&nft_limit_type); 235 } 236 237 module_init(nft_limit_module_init); 238 module_exit(nft_limit_module_exit); 239 240 MODULE_LICENSE("GPL"); 241 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); 242 MODULE_ALIAS_NFT_EXPR("limit"); 243