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             nla_put_be64(skb, NFTA_COUNTER_PACKETS, cpu_to_be64(total.packets)))
  81                 goto nla_put_failure;
  82         return 0;
  83
  84 nla_put_failure:
  85         return -1;
  86 }
  87
  88 static const struct nla_policy nft_counter_policy[NFTA_COUNTER_MAX + 1] = {
  89         [NFTA_COUNTER_PACKETS]  = { .type = NLA_U64 },
  90         [NFTA_COUNTER_BYTES]    = { .type = NLA_U64 },
  91 };
  92
  93 static int nft_counter_init(const struct nft_ctx *ctx,
  94                             const struct nft_expr *expr,
  95                             const struct nlattr * const tb[])
  96 {
  97         struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
  98         struct nft_counter_percpu __percpu *cpu_stats;
  99         struct nft_counter_percpu *this_cpu;
 100
 101         cpu_stats = netdev_alloc_pcpu_stats(struct nft_counter_percpu);
 102         if (cpu_stats == NULL)
 103                 return ENOMEM;
 104
 105         preempt_disable();
 106         this_cpu = this_cpu_ptr(cpu_stats);
 107         if (tb[NFTA_COUNTER_PACKETS]) {
 108                 this_cpu->counter.packets =
 109                         be64_to_cpu(nla_get_be64(tb[NFTA_COUNTER_PACKETS]));
 110         }
 111         if (tb[NFTA_COUNTER_BYTES]) {
 112                 this_cpu->counter.bytes =
 113                         be64_to_cpu(nla_get_be64(tb[NFTA_COUNTER_BYTES]));
 114         }
 115         preempt_enable();
 116         priv->counter = cpu_stats;
 117         return 0;
 118 }
 119
 120 static void nft_counter_destroy(const struct nft_ctx *ctx,
 121                                 const struct nft_expr *expr)
 122 {
 123         struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
 124
 125         free_percpu(priv->counter);
 126 }
 127
 128 static int nft_counter_clone(struct nft_expr *dst, const struct nft_expr *src)
 129 {
 130         struct nft_counter_percpu_priv *priv = nft_expr_priv(src);
 131         struct nft_counter_percpu_priv *priv_clone = nft_expr_priv(dst);
 132         struct nft_counter_percpu __percpu *cpu_stats;
 133         struct nft_counter_percpu *this_cpu;
 134         struct nft_counter total;
 135
 136         nft_counter_fetch(priv->counter, &total);
 137
 138         cpu_stats = __netdev_alloc_pcpu_stats(struct nft_counter_percpu,
 139                                               GFP_ATOMIC);
 140         if (cpu_stats == NULL)
 141                 return ENOMEM;
 142
 143         preempt_disable();
 144         this_cpu = this_cpu_ptr(cpu_stats);
 145         this_cpu->counter.packets = total.packets;
 146         this_cpu->counter.bytes = total.bytes;
 147         preempt_enable();
 148
 149         priv_clone->counter = cpu_stats;
 150         return 0;
 151 }
 152
 153 static struct nft_expr_type nft_counter_type;
 154 static const struct nft_expr_ops nft_counter_ops = {
 155         .type           = &nft_counter_type,
 156         .size           = NFT_EXPR_SIZE(sizeof(struct nft_counter_percpu_priv)),
 157         .eval           = nft_counter_eval,
 158         .init           = nft_counter_init,
 159         .destroy        = nft_counter_destroy,
 160         .dump           = nft_counter_dump,
 161         .clone          = nft_counter_clone,
 162 };
 163
 164 static struct nft_expr_type nft_counter_type __read_mostly = {
 165         .name           = "counter",
 166         .ops            = &nft_counter_ops,
 167         .policy         = nft_counter_policy,
 168         .maxattr        = NFTA_COUNTER_MAX,
 169         .flags          = NFT_EXPR_STATEFUL,
 170         .owner          = THIS_MODULE,
 171 };
 172
 173 static int __init nft_counter_module_init(void)
 174 {
 175         return nft_register_expr(&nft_counter_type);
 176 }
 177
 178 static void __exit nft_counter_module_exit(void)
 179 {
 180         nft_unregister_expr(&nft_counter_type);
 181 }
 182
 183 module_init(nft_counter_module_init);
 184 module_exit(nft_counter_module_exit);
 185
 186 MODULE_LICENSE("GPL");
 187 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 188 MODULE_ALIAS_NFT_EXPR("counter");