net/netfilter/nft_dynset.c

   1 /*
   2  * Copyright (c) 2015 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  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/init.h>
  13 #include <linux/netlink.h>
  14 #include <linux/netfilter.h>
  15 #include <linux/netfilter/nf_tables.h>
  16 #include <net/netfilter/nf_tables.h>
  17 #include <net/netfilter/nf_tables_core.h>
  18
  19 struct nft_dynset {
  20         struct nft_set                  *set;
  21         struct nft_set_ext_tmpl         tmpl;
  22         enum nft_dynset_ops             op:8;
  23         enum nft_registers              sreg_key:8;
  24         enum nft_registers              sreg_data:8;
  25         bool                            invert;
  26         u64                             timeout;
  27         struct nft_expr                 *expr;
  28         struct nft_set_binding          binding;
  29 };
  30
  31 static void *nft_dynset_new(struct nft_set *set, const struct nft_expr *expr,
  32                             struct nft_regs *regs)
  33 {
  34         const struct nft_dynset *priv = nft_expr_priv(expr);
  35         struct nft_set_ext *ext;
  36         u64 timeout;
  37         void *elem;
  38
  39         if (!atomic_add_unless(&set->nelems, 1, set->size))
  40                 return NULL;
  41
  42         timeout = priv->timeout ? : set->timeout;
  43         elem = nft_set_elem_init(set, &priv->tmpl,
  44                                  &regs->data[priv->sreg_key],
  45                                  &regs->data[priv->sreg_data],
  46                                  timeout, GFP_ATOMIC);
  47         if (elem == NULL)
  48                 goto err1;
  49
  50         ext = nft_set_elem_ext(set, elem);
  51         if (priv->expr != NULL &&
  52             nft_expr_clone(nft_set_ext_expr(ext), priv->expr) < 0)
  53                 goto err2;
  54
  55         return elem;
  56
  57 err2:
  58         nft_set_elem_destroy(set, elem, false);
  59 err1:
  60         if (set->size)
  61                 atomic_dec(&set->nelems);
  62         return NULL;
  63 }
  64
  65 static void nft_dynset_eval(const struct nft_expr *expr,
  66                             struct nft_regs *regs,
  67                             const struct nft_pktinfo *pkt)
  68 {
  69         const struct nft_dynset *priv = nft_expr_priv(expr);
  70         struct nft_set *set = priv->set;
  71         const struct nft_set_ext *ext;
  72         const struct nft_expr *sexpr;
  73         u64 timeout;
  74
  75         if (set->ops->update(set, &regs->data[priv->sreg_key], nft_dynset_new,
  76                              expr, regs, &ext)) {
  77                 sexpr = NULL;
  78                 if (nft_set_ext_exists(ext, NFT_SET_EXT_EXPR))
  79                         sexpr = nft_set_ext_expr(ext);
  80
  81                 if (priv->op == NFT_DYNSET_OP_UPDATE &&
  82                     nft_set_ext_exists(ext, NFT_SET_EXT_EXPIRATION)) {
  83                         timeout = priv->timeout ? : set->timeout;
  84                         *nft_set_ext_expiration(ext) = get_jiffies_64() + timeout;
  85                 }
  86
  87                 if (sexpr != NULL)
  88                         sexpr->ops->eval(sexpr, regs, pkt);
  89
  90                 if (priv->invert)
  91                         regs->verdict.code = NFT_BREAK;
  92                 return;
  93         }
  94
  95         if (!priv->invert)
  96                 regs->verdict.code = NFT_BREAK;
  97 }
  98
  99 static const struct nla_policy nft_dynset_policy[NFTA_DYNSET_MAX + 1] = {
 100         [NFTA_DYNSET_SET_NAME]  = { .type = NLA_STRING,
 101                                     .len = NFT_SET_MAXNAMELEN - 1 },
 102         [NFTA_DYNSET_SET_ID]    = { .type = NLA_U32 },
 103         [NFTA_DYNSET_OP]        = { .type = NLA_U32 },
 104         [NFTA_DYNSET_SREG_KEY]  = { .type = NLA_U32 },
 105         [NFTA_DYNSET_SREG_DATA] = { .type = NLA_U32 },
 106         [NFTA_DYNSET_TIMEOUT]   = { .type = NLA_U64 },
 107         [NFTA_DYNSET_EXPR]      = { .type = NLA_NESTED },
 108         [NFTA_DYNSET_FLAGS]     = { .type = NLA_U32 },
 109 };
 110
 111 static int nft_dynset_init(const struct nft_ctx *ctx,
 112                            const struct nft_expr *expr,
 113                            const struct nlattr * const tb[])
 114 {
 115         struct nft_dynset *priv = nft_expr_priv(expr);
 116         u8 genmask = nft_genmask_next(ctx->net);
 117         struct nft_set *set;
 118         u64 timeout;
 119         int err;
 120
 121         lockdep_assert_held(&ctx->net->nft.commit_mutex);
 122
 123         if (tb[NFTA_DYNSET_SET_NAME] == NULL ||
 124             tb[NFTA_DYNSET_OP] == NULL ||
 125             tb[NFTA_DYNSET_SREG_KEY] == NULL)
 126                 return -EINVAL;
 127
 128         if (tb[NFTA_DYNSET_FLAGS]) {
 129                 u32 flags = ntohl(nla_get_be32(tb[NFTA_DYNSET_FLAGS]));
 130
 131                 if (flags & ~NFT_DYNSET_F_INV)
 132                         return -EINVAL;
 133                 if (flags & NFT_DYNSET_F_INV)
 134                         priv->invert = true;
 135         }
 136
 137         set = nft_set_lookup_global(ctx->net, ctx->table,
 138                                     tb[NFTA_DYNSET_SET_NAME],
 139                                     tb[NFTA_DYNSET_SET_ID], genmask);
 140         if (IS_ERR(set))
 141                 return PTR_ERR(set);
 142
 143         if (set->ops->update == NULL)
 144                 return -EOPNOTSUPP;
 145
 146         if (set->flags & NFT_SET_CONSTANT)
 147                 return -EBUSY;
 148
 149         priv->op = ntohl(nla_get_be32(tb[NFTA_DYNSET_OP]));
 150         switch (priv->op) {
 151         case NFT_DYNSET_OP_ADD:
 152                 break;
 153         case NFT_DYNSET_OP_UPDATE:
 154                 if (!(set->flags & NFT_SET_TIMEOUT))
 155                         return -EOPNOTSUPP;
 156                 break;
 157         default:
 158                 return -EOPNOTSUPP;
 159         }
 160
 161         timeout = 0;
 162         if (tb[NFTA_DYNSET_TIMEOUT] != NULL) {
 163                 if (!(set->flags & NFT_SET_TIMEOUT))
 164                         return -EINVAL;
 165                 timeout = msecs_to_jiffies(be64_to_cpu(nla_get_be64(
 166                                                 tb[NFTA_DYNSET_TIMEOUT])));
 167         }
 168
 169         priv->sreg_key = nft_parse_register(tb[NFTA_DYNSET_SREG_KEY]);
 170         err = nft_validate_register_load(priv->sreg_key, set->klen);
 171         if (err < 0)
 172                 return err;
 173
 174         if (tb[NFTA_DYNSET_SREG_DATA] != NULL) {
 175                 if (!(set->flags & NFT_SET_MAP))
 176                         return -EINVAL;
 177                 if (set->dtype == NFT_DATA_VERDICT)
 178                         return -EOPNOTSUPP;
 179
 180                 priv->sreg_data = nft_parse_register(tb[NFTA_DYNSET_SREG_DATA]);
 181                 err = nft_validate_register_load(priv->sreg_data, set->dlen);
 182                 if (err < 0)
 183                         return err;
 184         } else if (set->flags & NFT_SET_MAP)
 185                 return -EINVAL;
 186
 187         if (tb[NFTA_DYNSET_EXPR] != NULL) {
 188                 if (!(set->flags & NFT_SET_EVAL))
 189                         return -EINVAL;
 190
 191                 priv->expr = nft_expr_init(ctx, tb[NFTA_DYNSET_EXPR]);
 192                 if (IS_ERR(priv->expr))
 193                         return PTR_ERR(priv->expr);
 194
 195                 err = -EOPNOTSUPP;
 196                 if (!(priv->expr->ops->type->flags & NFT_EXPR_STATEFUL))
 197                         goto err1;
 198
 199                 if (priv->expr->ops->type->flags & NFT_EXPR_GC) {
 200                         if (set->flags & NFT_SET_TIMEOUT)
 201                                 goto err1;
 202                         if (!set->ops->gc_init)
 203                                 goto err1;
 204                         set->ops->gc_init(set);
 205                 }
 206         }
 207
 208         nft_set_ext_prepare(&priv->tmpl);
 209         nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_KEY, set->klen);
 210         if (set->flags & NFT_SET_MAP)
 211                 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_DATA, set->dlen);
 212         if (priv->expr != NULL)
 213                 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_EXPR,
 214                                        priv->expr->ops->size);
 215         if (set->flags & NFT_SET_TIMEOUT) {
 216                 if (timeout || set->timeout)
 217                         nft_set_ext_add(&priv->tmpl, NFT_SET_EXT_EXPIRATION);
 218         }
 219
 220         priv->timeout = timeout;
 221
 222         err = nf_tables_bind_set(ctx, set, &priv->binding);
 223         if (err < 0)
 224                 goto err1;
 225
 226         if (set->size == 0)
 227                 set->size = 0xffff;
 228
 229         priv->set = set;
 230         return 0;
 231
 232 err1:
 233         if (priv->expr != NULL)
 234                 nft_expr_destroy(ctx, priv->expr);
 235         return err;
 236 }
 237
 238 static void nft_dynset_activate(const struct nft_ctx *ctx,
 239                                 const struct nft_expr *expr)
 240 {
 241         struct nft_dynset *priv = nft_expr_priv(expr);
 242
 243         nf_tables_rebind_set(ctx, priv->set, &priv->binding);
 244 }
 245
 246 static void nft_dynset_deactivate(const struct nft_ctx *ctx,
 247                                   const struct nft_expr *expr)
 248 {
 249         struct nft_dynset *priv = nft_expr_priv(expr);
 250
 251         nf_tables_unbind_set(ctx, priv->set, &priv->binding);
 252 }
 253
 254 static void nft_dynset_destroy(const struct nft_ctx *ctx,
 255                                const struct nft_expr *expr)
 256 {
 257         struct nft_dynset *priv = nft_expr_priv(expr);
 258
 259         if (priv->expr != NULL)
 260                 nft_expr_destroy(ctx, priv->expr);
 261
 262         nf_tables_destroy_set(ctx, priv->set);
 263 }
 264
 265 static int nft_dynset_dump(struct sk_buff *skb, const struct nft_expr *expr)
 266 {
 267         const struct nft_dynset *priv = nft_expr_priv(expr);
 268         u32 flags = priv->invert ? NFT_DYNSET_F_INV : 0;
 269
 270         if (nft_dump_register(skb, NFTA_DYNSET_SREG_KEY, priv->sreg_key))
 271                 goto nla_put_failure;
 272         if (priv->set->flags & NFT_SET_MAP &&
 273             nft_dump_register(skb, NFTA_DYNSET_SREG_DATA, priv->sreg_data))
 274                 goto nla_put_failure;
 275         if (nla_put_be32(skb, NFTA_DYNSET_OP, htonl(priv->op)))
 276                 goto nla_put_failure;
 277         if (nla_put_string(skb, NFTA_DYNSET_SET_NAME, priv->set->name))
 278                 goto nla_put_failure;
 279         if (nla_put_be64(skb, NFTA_DYNSET_TIMEOUT,
 280                          cpu_to_be64(jiffies_to_msecs(priv->timeout)),
 281                          NFTA_DYNSET_PAD))
 282                 goto nla_put_failure;
 283         if (priv->expr && nft_expr_dump(skb, NFTA_DYNSET_EXPR, priv->expr))
 284                 goto nla_put_failure;
 285         if (nla_put_be32(skb, NFTA_DYNSET_FLAGS, htonl(flags)))
 286                 goto nla_put_failure;
 287         return 0;
 288
 289 nla_put_failure:
 290         return -1;
 291 }
 292
 293 static const struct nft_expr_ops nft_dynset_ops = {
 294         .type           = &nft_dynset_type,
 295         .size           = NFT_EXPR_SIZE(sizeof(struct nft_dynset)),
 296         .eval           = nft_dynset_eval,
 297         .init           = nft_dynset_init,
 298         .destroy        = nft_dynset_destroy,
 299         .activate       = nft_dynset_activate,
 300         .deactivate     = nft_dynset_deactivate,
 301         .dump           = nft_dynset_dump,
 302 };
 303
 304 struct nft_expr_type nft_dynset_type __read_mostly = {
 305         .name           = "dynset",
 306         .ops            = &nft_dynset_ops,
 307         .policy         = nft_dynset_policy,
 308         .maxattr        = NFTA_DYNSET_MAX,
 309         .owner          = THIS_MODULE,
 310 };