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         u64             bytes;
  22         u64             packets;
  23 };
  24
  25 struct nft_counter_percpu {
  26         struct nft_counter      counter;
  27         struct u64_stats_sync   syncp;
  28 };
  29
  30 struct nft_counter_percpu_priv {
  31         struct nft_counter_percpu __percpu *counter;
  32 };
  33
  34 static void nft_counter_eval(const struct nft_expr *expr,
  35                              struct nft_regs *regs,
  36                              const struct nft_pktinfo *pkt)
  37 {
  38         struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
  39         struct nft_counter_percpu *this_cpu;
  40
  41         local_bh_disable();
  42         this_cpu = this_cpu_ptr(priv->counter);
  43         u64_stats_update_begin(&this_cpu->syncp);
  44         this_cpu->counter.bytes += pkt->skb->len;
  45         this_cpu->counter.packets++;
  46         u64_stats_update_end(&this_cpu->syncp);
  47         local_bh_enable();
  48 }
  49
  50 static void nft_counter_fetch(const struct nft_counter_percpu __percpu *counter,
  51                               struct nft_counter *total)
  52 {
  53         const struct nft_counter_percpu *cpu_stats;
  54         u64 bytes, packets;
  55         unsigned int seq;
  56         int cpu;
  57
  58         memset(total, 0, sizeof(*total));
  59         for_each_possible_cpu(cpu) {
  60                 cpu_stats = per_cpu_ptr(counter, cpu);
  61                 do {
  62                         seq     = u64_stats_fetch_begin_irq(&cpu_stats->syncp);
  63                         bytes   = cpu_stats->counter.bytes;
  64                         packets = cpu_stats->counter.packets;
  65                 } while (u64_stats_fetch_retry_irq(&cpu_stats->syncp, seq));
  66
  67                 total->packets += packets;
  68                 total->bytes += bytes;
  69         }
  70 }
  71
  72 static int nft_counter_dump(struct sk_buff *skb, const struct nft_expr *expr)
  73 {
  74         struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
  75         struct nft_counter total;
  76
  77         nft_counter_fetch(priv->counter, &total);
  78
  79         if (nla_put_be64(skb, NFTA_COUNTER_BYTES, cpu_to_be64(total.bytes),
  80                          NFTA_COUNTER_PAD) ||
  81             nla_put_be64(skb, NFTA_COUNTER_PACKETS, cpu_to_be64(total.packets),
  82                          NFTA_COUNTER_PAD))
  83                 goto nla_put_failure;
  84         return 0;
  85
  86 nla_put_failure:
  87         return -1;
  88 }
  89
  90 static const struct nla_policy nft_counter_policy[NFTA_COUNTER_MAX + 1] = {
  91         [NFTA_COUNTER_PACKETS]  = { .type = NLA_U64 },
  92         [NFTA_COUNTER_BYTES]    = { .type = NLA_U64 },
  93 };
  94
  95 static int nft_counter_init(const struct nft_ctx *ctx,
  96                             const struct nft_expr *expr,
  97                             const struct nlattr * const tb[])
  98 {
  99         struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
 100         struct nft_counter_percpu __percpu *cpu_stats;
 101         struct nft_counter_percpu *this_cpu;
 102
 103         cpu_stats = netdev_alloc_pcpu_stats(struct nft_counter_percpu);
 104         if (cpu_stats == NULL)
 105                 return -ENOMEM;
 106
 107         preempt_disable();
 108         this_cpu = this_cpu_ptr(cpu_stats);
 109         if (tb[NFTA_COUNTER_PACKETS]) {
 110                 this_cpu->counter.packets =
 111                         be64_to_cpu(nla_get_be64(tb[NFTA_COUNTER_PACKETS]));
 112         }
 113         if (tb[NFTA_COUNTER_BYTES]) {
 114                 this_cpu->counter.bytes =
 115                         be64_to_cpu(nla_get_be64(tb[NFTA_COUNTER_BYTES]));
 116         }
 117         preempt_enable();
 118         priv->counter = cpu_stats;
 119         return 0;
 120 }
 121
 122 static void nft_counter_destroy(const struct nft_ctx *ctx,
 123                                 const struct nft_expr *expr)
 124 {
 125         struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
 126
 127         free_percpu(priv->counter);
 128 }
 129
 130 static int nft_counter_clone(struct nft_expr *dst, const struct nft_expr *src)
 131 {
 132         struct nft_counter_percpu_priv *priv = nft_expr_priv(src);
 133         struct nft_counter_percpu_priv *priv_clone = nft_expr_priv(dst);
 134         struct nft_counter_percpu __percpu *cpu_stats;
 135         struct nft_counter_percpu *this_cpu;
 136         struct nft_counter total;
 137
 138         nft_counter_fetch(priv->counter, &total);
 139
 140         cpu_stats = __netdev_alloc_pcpu_stats(struct nft_counter_percpu,
 141                                               GFP_ATOMIC);
 142         if (cpu_stats == NULL)
 143                 return -ENOMEM;
 144
 145         preempt_disable();
 146         this_cpu = this_cpu_ptr(cpu_stats);
 147         this_cpu->counter.packets = total.packets;
 148         this_cpu->counter.bytes = total.bytes;
 149         preempt_enable();
 150
 151         priv_clone->counter = cpu_stats;
 152         return 0;
 153 }
 154
 155 static struct nft_expr_type nft_counter_type;
 156 static const struct nft_expr_ops nft_counter_ops = {
 157         .type           = &nft_counter_type,
 158         .size           = NFT_EXPR_SIZE(sizeof(struct nft_counter_percpu_priv)),
 159         .eval           = nft_counter_eval,
 160         .init           = nft_counter_init,
 161         .destroy        = nft_counter_destroy,
 162         .dump           = nft_counter_dump,
 163         .clone          = nft_counter_clone,
 164 };
 165
 166 static struct nft_expr_type nft_counter_type __read_mostly = {
 167         .name           = "counter",
 168         .ops            = &nft_counter_ops,
 169         .policy         = nft_counter_policy,
 170         .maxattr        = NFTA_COUNTER_MAX,
 171         .flags          = NFT_EXPR_STATEFUL,
 172         .owner          = THIS_MODULE,
 173 };
 174
 175 static int __init nft_counter_module_init(void)
 176 {
 177         return nft_register_expr(&nft_counter_type);
 178 }
 179
 180 static void __exit nft_counter_module_exit(void)
 181 {
 182         nft_unregister_expr(&nft_counter_type);
 183 }
 184
 185 module_init(nft_counter_module_init);
 186 module_exit(nft_counter_module_exit);
 187
 188 MODULE_LICENSE("GPL");
 189 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 190 MODULE_ALIAS_NFT_EXPR("counter");