net/netfilter/nft_counter.c

   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/seqlock.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 struct nft_counter {
  21         s64             bytes;
  22         s64             packets;
  23 };
  24
  25 struct nft_counter_percpu_priv {
  26         struct nft_counter __percpu *counter;
  27 };
  28
  29 static DEFINE_PER_CPU(seqcount_t, nft_counter_seq);
  30
  31 static inline void nft_counter_do_eval(struct nft_counter_percpu_priv *priv,
  32                                        struct nft_regs *regs,
  33                                        const struct nft_pktinfo *pkt)
  34 {
  35         struct nft_counter *this_cpu;
  36         seqcount_t *myseq;
  37
  38         local_bh_disable();
  39         this_cpu = this_cpu_ptr(priv->counter);
  40         myseq = this_cpu_ptr(&nft_counter_seq);
  41
  42         write_seqcount_begin(myseq);
  43
  44         this_cpu->bytes += pkt->skb->len;
  45         this_cpu->packets++;
  46
  47         write_seqcount_end(myseq);
  48         local_bh_enable();
  49 }
  50
  51 static inline void nft_counter_obj_eval(struct nft_object *obj,
  52                                         struct nft_regs *regs,
  53                                         const struct nft_pktinfo *pkt)
  54 {
  55         struct nft_counter_percpu_priv *priv = nft_obj_data(obj);
  56
  57         nft_counter_do_eval(priv, regs, pkt);
  58 }
  59
  60 static int nft_counter_do_init(const struct nlattr * const tb[],
  61                                struct nft_counter_percpu_priv *priv)
  62 {
  63         struct nft_counter __percpu *cpu_stats;
  64         struct nft_counter *this_cpu;
  65
  66         cpu_stats = alloc_percpu(struct nft_counter);
  67         if (cpu_stats == NULL)
  68                 return -ENOMEM;
  69
  70         preempt_disable();
  71         this_cpu = this_cpu_ptr(cpu_stats);
  72         if (tb[NFTA_COUNTER_PACKETS]) {
  73                 this_cpu->packets =
  74                         be64_to_cpu(nla_get_be64(tb[NFTA_COUNTER_PACKETS]));
  75         }
  76         if (tb[NFTA_COUNTER_BYTES]) {
  77                 this_cpu->bytes =
  78                         be64_to_cpu(nla_get_be64(tb[NFTA_COUNTER_BYTES]));
  79         }
  80         preempt_enable();
  81         priv->counter = cpu_stats;
  82         return 0;
  83 }
  84
  85 static int nft_counter_obj_init(const struct nlattr * const tb[],
  86                                 struct nft_object *obj)
  87 {
  88         struct nft_counter_percpu_priv *priv = nft_obj_data(obj);
  89
  90         return nft_counter_do_init(tb, priv);
  91 }
  92
  93 static void nft_counter_do_destroy(struct nft_counter_percpu_priv *priv)
  94 {
  95         free_percpu(priv->counter);
  96 }
  97
  98 static void nft_counter_obj_destroy(struct nft_object *obj)
  99 {
 100         struct nft_counter_percpu_priv *priv = nft_obj_data(obj);
 101
 102         nft_counter_do_destroy(priv);
 103 }
 104
 105 static void nft_counter_reset(struct nft_counter_percpu_priv __percpu *priv,
 106                               struct nft_counter *total)
 107 {
 108         struct nft_counter *this_cpu;
 109
 110         local_bh_disable();
 111         this_cpu = this_cpu_ptr(priv->counter);
 112         this_cpu->packets -= total->packets;
 113         this_cpu->bytes -= total->bytes;
 114         local_bh_enable();
 115 }
 116
 117 static void nft_counter_fetch(struct nft_counter_percpu_priv *priv,
 118                               struct nft_counter *total)
 119 {
 120         struct nft_counter *this_cpu;
 121         const seqcount_t *myseq;
 122         u64 bytes, packets;
 123         unsigned int seq;
 124         int cpu;
 125
 126         memset(total, 0, sizeof(*total));
 127         for_each_possible_cpu(cpu) {
 128                 myseq = per_cpu_ptr(&nft_counter_seq, cpu);
 129                 this_cpu = per_cpu_ptr(priv->counter, cpu);
 130                 do {
 131                         seq     = read_seqcount_begin(myseq);
 132                         bytes   = this_cpu->bytes;
 133                         packets = this_cpu->packets;
 134                 } while (read_seqcount_retry(myseq, seq));
 135
 136                 total->bytes    += bytes;
 137                 total->packets  += packets;
 138         }
 139 }
 140
 141 static int nft_counter_do_dump(struct sk_buff *skb,
 142                                struct nft_counter_percpu_priv *priv,
 143                                bool reset)
 144 {
 145         struct nft_counter total;
 146
 147         nft_counter_fetch(priv, &total);
 148
 149         if (nla_put_be64(skb, NFTA_COUNTER_BYTES, cpu_to_be64(total.bytes),
 150                          NFTA_COUNTER_PAD) ||
 151             nla_put_be64(skb, NFTA_COUNTER_PACKETS, cpu_to_be64(total.packets),
 152                          NFTA_COUNTER_PAD))
 153                 goto nla_put_failure;
 154
 155         if (reset)
 156                 nft_counter_reset(priv, &total);
 157
 158         return 0;
 159
 160 nla_put_failure:
 161         return -1;
 162 }
 163
 164 static int nft_counter_obj_dump(struct sk_buff *skb,
 165                                 struct nft_object *obj, bool reset)
 166 {
 167         struct nft_counter_percpu_priv *priv = nft_obj_data(obj);
 168
 169         return nft_counter_do_dump(skb, priv, reset);
 170 }
 171
 172 static const struct nla_policy nft_counter_policy[NFTA_COUNTER_MAX + 1] = {
 173         [NFTA_COUNTER_PACKETS]  = { .type = NLA_U64 },
 174         [NFTA_COUNTER_BYTES]    = { .type = NLA_U64 },
 175 };
 176
 177 static struct nft_object_type nft_counter_obj __read_mostly = {
 178         .type           = NFT_OBJECT_COUNTER,
 179         .size           = sizeof(struct nft_counter_percpu_priv),
 180         .maxattr        = NFTA_COUNTER_MAX,
 181         .policy         = nft_counter_policy,
 182         .eval           = nft_counter_obj_eval,
 183         .init           = nft_counter_obj_init,
 184         .destroy        = nft_counter_obj_destroy,
 185         .dump           = nft_counter_obj_dump,
 186         .owner          = THIS_MODULE,
 187 };
 188
 189 static void nft_counter_eval(const struct nft_expr *expr,
 190                              struct nft_regs *regs,
 191                              const struct nft_pktinfo *pkt)
 192 {
 193         struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
 194
 195         nft_counter_do_eval(priv, regs, pkt);
 196 }
 197
 198 static int nft_counter_dump(struct sk_buff *skb, const struct nft_expr *expr)
 199 {
 200         struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
 201
 202         return nft_counter_do_dump(skb, priv, false);
 203 }
 204
 205 static int nft_counter_init(const struct nft_ctx *ctx,
 206                             const struct nft_expr *expr,
 207                             const struct nlattr * const tb[])
 208 {
 209         struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
 210
 211         return nft_counter_do_init(tb, priv);
 212 }
 213
 214 static void nft_counter_destroy(const struct nft_ctx *ctx,
 215                                 const struct nft_expr *expr)
 216 {
 217         struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
 218
 219         nft_counter_do_destroy(priv);
 220 }
 221
 222 static int nft_counter_clone(struct nft_expr *dst, const struct nft_expr *src)
 223 {
 224         struct nft_counter_percpu_priv *priv = nft_expr_priv(src);
 225         struct nft_counter_percpu_priv *priv_clone = nft_expr_priv(dst);
 226         struct nft_counter __percpu *cpu_stats;
 227         struct nft_counter *this_cpu;
 228         struct nft_counter total;
 229
 230         nft_counter_fetch(priv, &total);
 231
 232         cpu_stats = alloc_percpu_gfp(struct nft_counter, GFP_ATOMIC);
 233         if (cpu_stats == NULL)
 234                 return -ENOMEM;
 235
 236         preempt_disable();
 237         this_cpu = this_cpu_ptr(cpu_stats);
 238         this_cpu->packets = total.packets;
 239         this_cpu->bytes = total.bytes;
 240         preempt_enable();
 241
 242         priv_clone->counter = cpu_stats;
 243         return 0;
 244 }
 245
 246 static struct nft_expr_type nft_counter_type;
 247 static const struct nft_expr_ops nft_counter_ops = {
 248         .type           = &nft_counter_type,
 249         .size           = NFT_EXPR_SIZE(sizeof(struct nft_counter_percpu_priv)),
 250         .eval           = nft_counter_eval,
 251         .init           = nft_counter_init,
 252         .destroy        = nft_counter_destroy,
 253         .dump           = nft_counter_dump,
 254         .clone          = nft_counter_clone,
 255 };
 256
 257 static struct nft_expr_type nft_counter_type __read_mostly = {
 258         .name           = "counter",
 259         .ops            = &nft_counter_ops,
 260         .policy         = nft_counter_policy,
 261         .maxattr        = NFTA_COUNTER_MAX,
 262         .flags          = NFT_EXPR_STATEFUL,
 263         .owner          = THIS_MODULE,
 264 };
 265
 266 static int __init nft_counter_module_init(void)
 267 {
 268         int cpu, err;
 269
 270         for_each_possible_cpu(cpu)
 271                 seqcount_init(per_cpu_ptr(&nft_counter_seq, cpu));
 272
 273         err = nft_register_obj(&nft_counter_obj);
 274         if (err < 0)
 275                 return err;
 276
 277         err = nft_register_expr(&nft_counter_type);
 278         if (err < 0)
 279                 goto err1;
 280
 281         return 0;
 282 err1:
 283         nft_unregister_obj(&nft_counter_obj);
 284         return err;
 285 }
 286
 287 static void __exit nft_counter_module_exit(void)
 288 {
 289         nft_unregister_expr(&nft_counter_type);
 290         nft_unregister_obj(&nft_counter_obj);
 291 }
 292
 293 module_init(nft_counter_module_init);
 294 module_exit(nft_counter_module_exit);
 295
 296 MODULE_LICENSE("GPL");
 297 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 298 MODULE_ALIAS_NFT_EXPR("counter");
 299 MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_COUNTER);