net/netfilter/nft_counter.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
   4  *
   5  * Development of this code funded by Astaro AG (http://www.astaro.com/)
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/init.h>
  10 #include <linux/module.h>
  11 #include <linux/seqlock.h>
  12 #include <linux/netlink.h>
  13 #include <linux/netfilter.h>
  14 #include <linux/netfilter/nf_tables.h>
  15 #include <net/netfilter/nf_tables.h>
  16 #include <net/netfilter/nf_tables_core.h>
  17 #include <net/netfilter/nf_tables_offload.h>
  18
  19 struct nft_counter {
  20         s64             bytes;
  21         s64             packets;
  22 };
  23
  24 struct nft_counter_percpu_priv {
  25         struct nft_counter __percpu *counter;
  26 };
  27
  28 static DEFINE_PER_CPU(seqcount_t, nft_counter_seq);
  29
  30 static inline void nft_counter_do_eval(struct nft_counter_percpu_priv *priv,
  31                                        struct nft_regs *regs,
  32                                        const struct nft_pktinfo *pkt)
  33 {
  34         struct nft_counter *this_cpu;
  35         seqcount_t *myseq;
  36
  37         local_bh_disable();
  38         this_cpu = this_cpu_ptr(priv->counter);
  39         myseq = this_cpu_ptr(&nft_counter_seq);
  40
  41         write_seqcount_begin(myseq);
  42
  43         this_cpu->bytes += pkt->skb->len;
  44         this_cpu->packets++;
  45
  46         write_seqcount_end(myseq);
  47         local_bh_enable();
  48 }
  49
  50 static inline void nft_counter_obj_eval(struct nft_object *obj,
  51                                         struct nft_regs *regs,
  52                                         const struct nft_pktinfo *pkt)
  53 {
  54         struct nft_counter_percpu_priv *priv = nft_obj_data(obj);
  55
  56         nft_counter_do_eval(priv, regs, pkt);
  57 }
  58
  59 static int nft_counter_do_init(const struct nlattr * const tb[],
  60                                struct nft_counter_percpu_priv *priv)
  61 {
  62         struct nft_counter __percpu *cpu_stats;
  63         struct nft_counter *this_cpu;
  64
  65         cpu_stats = alloc_percpu_gfp(struct nft_counter, GFP_KERNEL_ACCOUNT);
  66         if (cpu_stats == NULL)
  67                 return -ENOMEM;
  68
  69         preempt_disable();
  70         this_cpu = this_cpu_ptr(cpu_stats);
  71         if (tb[NFTA_COUNTER_PACKETS]) {
  72                 this_cpu->packets =
  73                         be64_to_cpu(nla_get_be64(tb[NFTA_COUNTER_PACKETS]));
  74         }
  75         if (tb[NFTA_COUNTER_BYTES]) {
  76                 this_cpu->bytes =
  77                         be64_to_cpu(nla_get_be64(tb[NFTA_COUNTER_BYTES]));
  78         }
  79         preempt_enable();
  80         priv->counter = cpu_stats;
  81         return 0;
  82 }
  83
  84 static int nft_counter_obj_init(const struct nft_ctx *ctx,
  85                                 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(const struct nft_ctx *ctx,
  99                                     struct nft_object *obj)
 100 {
 101         struct nft_counter_percpu_priv *priv = nft_obj_data(obj);
 102
 103         nft_counter_do_destroy(priv);
 104 }
 105
 106 static void nft_counter_reset(struct nft_counter_percpu_priv *priv,
 107                               struct nft_counter *total)
 108 {
 109         struct nft_counter *this_cpu;
 110
 111         local_bh_disable();
 112         this_cpu = this_cpu_ptr(priv->counter);
 113         this_cpu->packets -= total->packets;
 114         this_cpu->bytes -= total->bytes;
 115         local_bh_enable();
 116 }
 117
 118 static void nft_counter_fetch(struct nft_counter_percpu_priv *priv,
 119                               struct nft_counter *total)
 120 {
 121         struct nft_counter *this_cpu;
 122         const seqcount_t *myseq;
 123         u64 bytes, packets;
 124         unsigned int seq;
 125         int cpu;
 126
 127         memset(total, 0, sizeof(*total));
 128         for_each_possible_cpu(cpu) {
 129                 myseq = per_cpu_ptr(&nft_counter_seq, cpu);
 130                 this_cpu = per_cpu_ptr(priv->counter, cpu);
 131                 do {
 132                         seq     = read_seqcount_begin(myseq);
 133                         bytes   = this_cpu->bytes;
 134                         packets = this_cpu->packets;
 135                 } while (read_seqcount_retry(myseq, seq));
 136
 137                 total->bytes    += bytes;
 138                 total->packets  += packets;
 139         }
 140 }
 141
 142 static int nft_counter_do_dump(struct sk_buff *skb,
 143                                struct nft_counter_percpu_priv *priv,
 144                                bool reset)
 145 {
 146         struct nft_counter total;
 147
 148         nft_counter_fetch(priv, &total);
 149
 150         if (nla_put_be64(skb, NFTA_COUNTER_BYTES, cpu_to_be64(total.bytes),
 151                          NFTA_COUNTER_PAD) ||
 152             nla_put_be64(skb, NFTA_COUNTER_PACKETS, cpu_to_be64(total.packets),
 153                          NFTA_COUNTER_PAD))
 154                 goto nla_put_failure;
 155
 156         if (reset)
 157                 nft_counter_reset(priv, &total);
 158
 159         return 0;
 160
 161 nla_put_failure:
 162         return -1;
 163 }
 164
 165 static int nft_counter_obj_dump(struct sk_buff *skb,
 166                                 struct nft_object *obj, bool reset)
 167 {
 168         struct nft_counter_percpu_priv *priv = nft_obj_data(obj);
 169
 170         return nft_counter_do_dump(skb, priv, reset);
 171 }
 172
 173 static const struct nla_policy nft_counter_policy[NFTA_COUNTER_MAX + 1] = {
 174         [NFTA_COUNTER_PACKETS]  = { .type = NLA_U64 },
 175         [NFTA_COUNTER_BYTES]    = { .type = NLA_U64 },
 176 };
 177
 178 struct nft_object_type nft_counter_obj_type;
 179 static const struct nft_object_ops nft_counter_obj_ops = {
 180         .type           = &nft_counter_obj_type,
 181         .size           = sizeof(struct nft_counter_percpu_priv),
 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 };
 187
 188 struct nft_object_type nft_counter_obj_type __read_mostly = {
 189         .type           = NFT_OBJECT_COUNTER,
 190         .ops            = &nft_counter_obj_ops,
 191         .maxattr        = NFTA_COUNTER_MAX,
 192         .policy         = nft_counter_policy,
 193         .owner          = THIS_MODULE,
 194 };
 195
 196 void nft_counter_eval(const struct nft_expr *expr, struct nft_regs *regs,
 197                       const struct nft_pktinfo *pkt)
 198 {
 199         struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
 200
 201         nft_counter_do_eval(priv, regs, pkt);
 202 }
 203
 204 static int nft_counter_dump(struct sk_buff *skb, const struct nft_expr *expr)
 205 {
 206         struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
 207
 208         return nft_counter_do_dump(skb, priv, false);
 209 }
 210
 211 static int nft_counter_init(const struct nft_ctx *ctx,
 212                             const struct nft_expr *expr,
 213                             const struct nlattr * const tb[])
 214 {
 215         struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
 216
 217         return nft_counter_do_init(tb, priv);
 218 }
 219
 220 static void nft_counter_destroy(const struct nft_ctx *ctx,
 221                                 const struct nft_expr *expr)
 222 {
 223         struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
 224
 225         nft_counter_do_destroy(priv);
 226 }
 227
 228 static int nft_counter_clone(struct nft_expr *dst, const struct nft_expr *src)
 229 {
 230         struct nft_counter_percpu_priv *priv = nft_expr_priv(src);
 231         struct nft_counter_percpu_priv *priv_clone = nft_expr_priv(dst);
 232         struct nft_counter __percpu *cpu_stats;
 233         struct nft_counter *this_cpu;
 234         struct nft_counter total;
 235
 236         nft_counter_fetch(priv, &total);
 237
 238         cpu_stats = alloc_percpu_gfp(struct nft_counter, GFP_ATOMIC);
 239         if (cpu_stats == NULL)
 240                 return -ENOMEM;
 241
 242         preempt_disable();
 243         this_cpu = this_cpu_ptr(cpu_stats);
 244         this_cpu->packets = total.packets;
 245         this_cpu->bytes = total.bytes;
 246         preempt_enable();
 247
 248         priv_clone->counter = cpu_stats;
 249         return 0;
 250 }
 251
 252 static int nft_counter_offload(struct nft_offload_ctx *ctx,
 253                                struct nft_flow_rule *flow,
 254                                const struct nft_expr *expr)
 255 {
 256         /* No specific offload action is needed, but report success. */
 257         return 0;
 258 }
 259
 260 static void nft_counter_offload_stats(struct nft_expr *expr,
 261                                       const struct flow_stats *stats)
 262 {
 263         struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
 264         struct nft_counter *this_cpu;
 265         seqcount_t *myseq;
 266
 267         preempt_disable();
 268         this_cpu = this_cpu_ptr(priv->counter);
 269         myseq = this_cpu_ptr(&nft_counter_seq);
 270
 271         write_seqcount_begin(myseq);
 272         this_cpu->packets += stats->pkts;
 273         this_cpu->bytes += stats->bytes;
 274         write_seqcount_end(myseq);
 275         preempt_enable();
 276 }
 277
 278 void nft_counter_init_seqcount(void)
 279 {
 280         int cpu;
 281
 282         for_each_possible_cpu(cpu)
 283                 seqcount_init(per_cpu_ptr(&nft_counter_seq, cpu));
 284 }
 285
 286 struct nft_expr_type nft_counter_type;
 287 static const struct nft_expr_ops nft_counter_ops = {
 288         .type           = &nft_counter_type,
 289         .size           = NFT_EXPR_SIZE(sizeof(struct nft_counter_percpu_priv)),
 290         .eval           = nft_counter_eval,
 291         .init           = nft_counter_init,
 292         .destroy        = nft_counter_destroy,
 293         .destroy_clone  = nft_counter_destroy,
 294         .dump           = nft_counter_dump,
 295         .clone          = nft_counter_clone,
 296         .reduce         = NFT_REDUCE_READONLY,
 297         .offload        = nft_counter_offload,
 298         .offload_stats  = nft_counter_offload_stats,
 299 };
 300
 301 struct nft_expr_type nft_counter_type __read_mostly = {
 302         .name           = "counter",
 303         .ops            = &nft_counter_ops,
 304         .policy         = nft_counter_policy,
 305         .maxattr        = NFTA_COUNTER_MAX,
 306         .flags          = NFT_EXPR_STATEFUL,
 307         .owner          = THIS_MODULE,
 308 };