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 nft_ctx *ctx,
  86                                 const struct nlattr * const tb[],
  87                                 struct nft_object *obj)
  88 {
  89         struct nft_counter_percpu_priv *priv = nft_obj_data(obj);
  90
  91         return nft_counter_do_init(tb, priv);
  92 }
  93
  94 static void nft_counter_do_destroy(struct nft_counter_percpu_priv *priv)
  95 {
  96         free_percpu(priv->counter);
  97 }
  98
  99 static void nft_counter_obj_destroy(const struct nft_ctx *ctx,
 100                                     struct nft_object *obj)
 101 {
 102         struct nft_counter_percpu_priv *priv = nft_obj_data(obj);
 103
 104         nft_counter_do_destroy(priv);
 105 }
 106
 107 static void nft_counter_reset(struct nft_counter_percpu_priv __percpu *priv,
 108                               struct nft_counter *total)
 109 {
 110         struct nft_counter *this_cpu;
 111
 112         local_bh_disable();
 113         this_cpu = this_cpu_ptr(priv->counter);
 114         this_cpu->packets -= total->packets;
 115         this_cpu->bytes -= total->bytes;
 116         local_bh_enable();
 117 }
 118
 119 static void nft_counter_fetch(struct nft_counter_percpu_priv *priv,
 120                               struct nft_counter *total)
 121 {
 122         struct nft_counter *this_cpu;
 123         const seqcount_t *myseq;
 124         u64 bytes, packets;
 125         unsigned int seq;
 126         int cpu;
 127
 128         memset(total, 0, sizeof(*total));
 129         for_each_possible_cpu(cpu) {
 130                 myseq = per_cpu_ptr(&nft_counter_seq, cpu);
 131                 this_cpu = per_cpu_ptr(priv->counter, cpu);
 132                 do {
 133                         seq     = read_seqcount_begin(myseq);
 134                         bytes   = this_cpu->bytes;
 135                         packets = this_cpu->packets;
 136                 } while (read_seqcount_retry(myseq, seq));
 137
 138                 total->bytes    += bytes;
 139                 total->packets  += packets;
 140         }
 141 }
 142
 143 static int nft_counter_do_dump(struct sk_buff *skb,
 144                                struct nft_counter_percpu_priv *priv,
 145                                bool reset)
 146 {
 147         struct nft_counter total;
 148
 149         nft_counter_fetch(priv, &total);
 150
 151         if (nla_put_be64(skb, NFTA_COUNTER_BYTES, cpu_to_be64(total.bytes),
 152                          NFTA_COUNTER_PAD) ||
 153             nla_put_be64(skb, NFTA_COUNTER_PACKETS, cpu_to_be64(total.packets),
 154                          NFTA_COUNTER_PAD))
 155                 goto nla_put_failure;
 156
 157         if (reset)
 158                 nft_counter_reset(priv, &total);
 159
 160         return 0;
 161
 162 nla_put_failure:
 163         return -1;
 164 }
 165
 166 static int nft_counter_obj_dump(struct sk_buff *skb,
 167                                 struct nft_object *obj, bool reset)
 168 {
 169         struct nft_counter_percpu_priv *priv = nft_obj_data(obj);
 170
 171         return nft_counter_do_dump(skb, priv, reset);
 172 }
 173
 174 static const struct nla_policy nft_counter_policy[NFTA_COUNTER_MAX + 1] = {
 175         [NFTA_COUNTER_PACKETS]  = { .type = NLA_U64 },
 176         [NFTA_COUNTER_BYTES]    = { .type = NLA_U64 },
 177 };
 178
 179 static struct nft_object_type nft_counter_obj_type;
 180 static const struct nft_object_ops nft_counter_obj_ops = {
 181         .type           = &nft_counter_obj_type,
 182         .size           = sizeof(struct nft_counter_percpu_priv),
 183         .eval           = nft_counter_obj_eval,
 184         .init           = nft_counter_obj_init,
 185         .destroy        = nft_counter_obj_destroy,
 186         .dump           = nft_counter_obj_dump,
 187 };
 188
 189 static struct nft_object_type nft_counter_obj_type __read_mostly = {
 190         .type           = NFT_OBJECT_COUNTER,
 191         .ops            = &nft_counter_obj_ops,
 192         .maxattr        = NFTA_COUNTER_MAX,
 193         .policy         = nft_counter_policy,
 194         .owner          = THIS_MODULE,
 195 };
 196
 197 static void nft_counter_eval(const struct nft_expr *expr,
 198                              struct nft_regs *regs,
 199                              const struct nft_pktinfo *pkt)
 200 {
 201         struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
 202
 203         nft_counter_do_eval(priv, regs, pkt);
 204 }
 205
 206 static int nft_counter_dump(struct sk_buff *skb, const struct nft_expr *expr)
 207 {
 208         struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
 209
 210         return nft_counter_do_dump(skb, priv, false);
 211 }
 212
 213 static int nft_counter_init(const struct nft_ctx *ctx,
 214                             const struct nft_expr *expr,
 215                             const struct nlattr * const tb[])
 216 {
 217         struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
 218
 219         return nft_counter_do_init(tb, priv);
 220 }
 221
 222 static void nft_counter_destroy(const struct nft_ctx *ctx,
 223                                 const struct nft_expr *expr)
 224 {
 225         struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
 226
 227         nft_counter_do_destroy(priv);
 228 }
 229
 230 static int nft_counter_clone(struct nft_expr *dst, const struct nft_expr *src)
 231 {
 232         struct nft_counter_percpu_priv *priv = nft_expr_priv(src);
 233         struct nft_counter_percpu_priv *priv_clone = nft_expr_priv(dst);
 234         struct nft_counter __percpu *cpu_stats;
 235         struct nft_counter *this_cpu;
 236         struct nft_counter total;
 237
 238         nft_counter_fetch(priv, &total);
 239
 240         cpu_stats = alloc_percpu_gfp(struct nft_counter, GFP_ATOMIC);
 241         if (cpu_stats == NULL)
 242                 return -ENOMEM;
 243
 244         preempt_disable();
 245         this_cpu = this_cpu_ptr(cpu_stats);
 246         this_cpu->packets = total.packets;
 247         this_cpu->bytes = total.bytes;
 248         preempt_enable();
 249
 250         priv_clone->counter = cpu_stats;
 251         return 0;
 252 }
 253
 254 static struct nft_expr_type nft_counter_type;
 255 static const struct nft_expr_ops nft_counter_ops = {
 256         .type           = &nft_counter_type,
 257         .size           = NFT_EXPR_SIZE(sizeof(struct nft_counter_percpu_priv)),
 258         .eval           = nft_counter_eval,
 259         .init           = nft_counter_init,
 260         .destroy        = nft_counter_destroy,
 261         .destroy_clone  = nft_counter_destroy,
 262         .dump           = nft_counter_dump,
 263         .clone          = nft_counter_clone,
 264 };
 265
 266 static struct nft_expr_type nft_counter_type __read_mostly = {
 267         .name           = "counter",
 268         .ops            = &nft_counter_ops,
 269         .policy         = nft_counter_policy,
 270         .maxattr        = NFTA_COUNTER_MAX,
 271         .flags          = NFT_EXPR_STATEFUL,
 272         .owner          = THIS_MODULE,
 273 };
 274
 275 static int __init nft_counter_module_init(void)
 276 {
 277         int cpu, err;
 278
 279         for_each_possible_cpu(cpu)
 280                 seqcount_init(per_cpu_ptr(&nft_counter_seq, cpu));
 281
 282         err = nft_register_obj(&nft_counter_obj_type);
 283         if (err < 0)
 284                 return err;
 285
 286         err = nft_register_expr(&nft_counter_type);
 287         if (err < 0)
 288                 goto err1;
 289
 290         return 0;
 291 err1:
 292         nft_unregister_obj(&nft_counter_obj_type);
 293         return err;
 294 }
 295
 296 static void __exit nft_counter_module_exit(void)
 297 {
 298         nft_unregister_expr(&nft_counter_type);
 299         nft_unregister_obj(&nft_counter_obj_type);
 300 }
 301
 302 module_init(nft_counter_module_init);
 303 module_exit(nft_counter_module_exit);
 304
 305 MODULE_LICENSE("GPL");
 306 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 307 MODULE_ALIAS_NFT_EXPR("counter");
 308 MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_COUNTER);