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_offload.h>
  17
  18 struct nft_counter {
  19         s64             bytes;
  20         s64             packets;
  21 };
  22
  23 struct nft_counter_percpu_priv {
  24         struct nft_counter __percpu *counter;
  25 };
  26
  27 static DEFINE_PER_CPU(seqcount_t, nft_counter_seq);
  28
  29 static inline void nft_counter_do_eval(struct nft_counter_percpu_priv *priv,
  30                                        struct nft_regs *regs,
  31                                        const struct nft_pktinfo *pkt)
  32 {
  33         struct nft_counter *this_cpu;
  34         seqcount_t *myseq;
  35
  36         local_bh_disable();
  37         this_cpu = this_cpu_ptr(priv->counter);
  38         myseq = this_cpu_ptr(&nft_counter_seq);
  39
  40         write_seqcount_begin(myseq);
  41
  42         this_cpu->bytes += pkt->skb->len;
  43         this_cpu->packets++;
  44
  45         write_seqcount_end(myseq);
  46         local_bh_enable();
  47 }
  48
  49 static inline void nft_counter_obj_eval(struct nft_object *obj,
  50                                         struct nft_regs *regs,
  51                                         const struct nft_pktinfo *pkt)
  52 {
  53         struct nft_counter_percpu_priv *priv = nft_obj_data(obj);
  54
  55         nft_counter_do_eval(priv, regs, pkt);
  56 }
  57
  58 static int nft_counter_do_init(const struct nlattr * const tb[],
  59                                struct nft_counter_percpu_priv *priv)
  60 {
  61         struct nft_counter __percpu *cpu_stats;
  62         struct nft_counter *this_cpu;
  63
  64         cpu_stats = alloc_percpu(struct nft_counter);
  65         if (cpu_stats == NULL)
  66                 return -ENOMEM;
  67
  68         preempt_disable();
  69         this_cpu = this_cpu_ptr(cpu_stats);
  70         if (tb[NFTA_COUNTER_PACKETS]) {
  71                 this_cpu->packets =
  72                         be64_to_cpu(nla_get_be64(tb[NFTA_COUNTER_PACKETS]));
  73         }
  74         if (tb[NFTA_COUNTER_BYTES]) {
  75                 this_cpu->bytes =
  76                         be64_to_cpu(nla_get_be64(tb[NFTA_COUNTER_BYTES]));
  77         }
  78         preempt_enable();
  79         priv->counter = cpu_stats;
  80         return 0;
  81 }
  82
  83 static int nft_counter_obj_init(const struct nft_ctx *ctx,
  84                                 const struct nlattr * const tb[],
  85                                 struct nft_object *obj)
  86 {
  87         struct nft_counter_percpu_priv *priv = nft_obj_data(obj);
  88
  89         return nft_counter_do_init(tb, priv);
  90 }
  91
  92 static void nft_counter_do_destroy(struct nft_counter_percpu_priv *priv)
  93 {
  94         free_percpu(priv->counter);
  95 }
  96
  97 static void nft_counter_obj_destroy(const struct nft_ctx *ctx,
  98                                     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 *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_type;
 178 static const struct nft_object_ops nft_counter_obj_ops = {
 179         .type           = &nft_counter_obj_type,
 180         .size           = sizeof(struct nft_counter_percpu_priv),
 181         .eval           = nft_counter_obj_eval,
 182         .init           = nft_counter_obj_init,
 183         .destroy        = nft_counter_obj_destroy,
 184         .dump           = nft_counter_obj_dump,
 185 };
 186
 187 static struct nft_object_type nft_counter_obj_type __read_mostly = {
 188         .type           = NFT_OBJECT_COUNTER,
 189         .ops            = &nft_counter_obj_ops,
 190         .maxattr        = NFTA_COUNTER_MAX,
 191         .policy         = nft_counter_policy,
 192         .owner          = THIS_MODULE,
 193 };
 194
 195 static void nft_counter_eval(const struct nft_expr *expr,
 196                              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 static struct nft_expr_type nft_counter_type;
 279 static const struct nft_expr_ops nft_counter_ops = {
 280         .type           = &nft_counter_type,
 281         .size           = NFT_EXPR_SIZE(sizeof(struct nft_counter_percpu_priv)),
 282         .eval           = nft_counter_eval,
 283         .init           = nft_counter_init,
 284         .destroy        = nft_counter_destroy,
 285         .destroy_clone  = nft_counter_destroy,
 286         .dump           = nft_counter_dump,
 287         .clone          = nft_counter_clone,
 288         .offload        = nft_counter_offload,
 289         .offload_stats  = nft_counter_offload_stats,
 290 };
 291
 292 static struct nft_expr_type nft_counter_type __read_mostly = {
 293         .name           = "counter",
 294         .ops            = &nft_counter_ops,
 295         .policy         = nft_counter_policy,
 296         .maxattr        = NFTA_COUNTER_MAX,
 297         .flags          = NFT_EXPR_STATEFUL,
 298         .owner          = THIS_MODULE,
 299 };
 300
 301 static int __init nft_counter_module_init(void)
 302 {
 303         int cpu, err;
 304
 305         for_each_possible_cpu(cpu)
 306                 seqcount_init(per_cpu_ptr(&nft_counter_seq, cpu));
 307
 308         err = nft_register_obj(&nft_counter_obj_type);
 309         if (err < 0)
 310                 return err;
 311
 312         err = nft_register_expr(&nft_counter_type);
 313         if (err < 0)
 314                 goto err1;
 315
 316         return 0;
 317 err1:
 318         nft_unregister_obj(&nft_counter_obj_type);
 319         return err;
 320 }
 321
 322 static void __exit nft_counter_module_exit(void)
 323 {
 324         nft_unregister_expr(&nft_counter_type);
 325         nft_unregister_obj(&nft_counter_obj_type);
 326 }
 327
 328 module_init(nft_counter_module_init);
 329 module_exit(nft_counter_module_exit);
 330
 331 MODULE_LICENSE("GPL");
 332 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 333 MODULE_ALIAS_NFT_EXPR("counter");
 334 MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_COUNTER);
 335 MODULE_DESCRIPTION("nftables counter rule support");