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 void nft_dynset_eval(const struct nft_expr *expr,
  66                      struct nft_regs *regs, const struct nft_pktinfo *pkt)
  67 {
  68         const struct nft_dynset *priv = nft_expr_priv(expr);
  69         struct nft_set *set = priv->set;
  70         const struct nft_set_ext *ext;
  71         const struct nft_expr *sexpr;
  72         u64 timeout;
  73
  74         if (set->ops->update(set, &regs->data[priv->sreg_key], nft_dynset_new,
  75                              expr, regs, &ext)) {
  76                 sexpr = NULL;
  77                 if (nft_set_ext_exists(ext, NFT_SET_EXT_EXPR))
  78                         sexpr = nft_set_ext_expr(ext);
  79
  80                 if (priv->op == NFT_DYNSET_OP_UPDATE &&
  81                     nft_set_ext_exists(ext, NFT_SET_EXT_EXPIRATION)) {
  82                         timeout = priv->timeout ? : set->timeout;
  83                         *nft_set_ext_expiration(ext) = get_jiffies_64() + timeout;
  84                 }
  85
  86                 if (sexpr != NULL)
  87                         sexpr->ops->eval(sexpr, regs, pkt);
  88
  89                 if (priv->invert)
  90                         regs->verdict.code = NFT_BREAK;
  91                 return;
  92         }
  93
  94         if (!priv->invert)
  95                 regs->verdict.code = NFT_BREAK;
  96 }
  97
  98 static const struct nla_policy nft_dynset_policy[NFTA_DYNSET_MAX + 1] = {
  99         [NFTA_DYNSET_SET_NAME]  = { .type = NLA_STRING,
 100                                     .len = NFT_SET_MAXNAMELEN - 1 },
 101         [NFTA_DYNSET_SET_ID]    = { .type = NLA_U32 },
 102         [NFTA_DYNSET_OP]        = { .type = NLA_U32 },
 103         [NFTA_DYNSET_SREG_KEY]  = { .type = NLA_U32 },
 104         [NFTA_DYNSET_SREG_DATA] = { .type = NLA_U32 },
 105         [NFTA_DYNSET_TIMEOUT]   = { .type = NLA_U64 },
 106         [NFTA_DYNSET_EXPR]      = { .type = NLA_NESTED },
 107         [NFTA_DYNSET_FLAGS]     = { .type = NLA_U32 },
 108 };
 109
 110 static int nft_dynset_init(const struct nft_ctx *ctx,
 111                            const struct nft_expr *expr,
 112                            const struct nlattr * const tb[])
 113 {
 114         struct nft_dynset *priv = nft_expr_priv(expr);
 115         u8 genmask = nft_genmask_next(ctx->net);
 116         struct nft_set *set;
 117         u64 timeout;
 118         int err;
 119
 120         lockdep_assert_held(&ctx->net->nft.commit_mutex);
 121
 122         if (tb[NFTA_DYNSET_SET_NAME] == NULL ||
 123             tb[NFTA_DYNSET_OP] == NULL ||
 124             tb[NFTA_DYNSET_SREG_KEY] == NULL)
 125                 return -EINVAL;
 126
 127         if (tb[NFTA_DYNSET_FLAGS]) {
 128                 u32 flags = ntohl(nla_get_be32(tb[NFTA_DYNSET_FLAGS]));
 129
 130                 if (flags & ~NFT_DYNSET_F_INV)
 131                         return -EINVAL;
 132                 if (flags & NFT_DYNSET_F_INV)
 133                         priv->invert = true;
 134         }
 135
 136         set = nft_set_lookup_global(ctx->net, ctx->table,
 137                                     tb[NFTA_DYNSET_SET_NAME],
 138                                     tb[NFTA_DYNSET_SET_ID], genmask);
 139         if (IS_ERR(set))
 140                 return PTR_ERR(set);
 141
 142         if (set->ops->update == NULL)
 143                 return -EOPNOTSUPP;
 144
 145         if (set->flags & NFT_SET_CONSTANT)
 146                 return -EBUSY;
 147
 148         priv->op = ntohl(nla_get_be32(tb[NFTA_DYNSET_OP]));
 149         switch (priv->op) {
 150         case NFT_DYNSET_OP_ADD:
 151                 break;
 152         case NFT_DYNSET_OP_UPDATE:
 153                 if (!(set->flags & NFT_SET_TIMEOUT))
 154                         return -EOPNOTSUPP;
 155                 break;
 156         default:
 157                 return -EOPNOTSUPP;
 158         }
 159
 160         timeout = 0;
 161         if (tb[NFTA_DYNSET_TIMEOUT] != NULL) {
 162                 if (!(set->flags & NFT_SET_TIMEOUT))
 163                         return -EINVAL;
 164                 timeout = msecs_to_jiffies(be64_to_cpu(nla_get_be64(
 165                                                 tb[NFTA_DYNSET_TIMEOUT])));
 166         }
 167
 168         priv->sreg_key = nft_parse_register(tb[NFTA_DYNSET_SREG_KEY]);
 169         err = nft_validate_register_load(priv->sreg_key, set->klen);
 170         if (err < 0)
 171                 return err;
 172
 173         if (tb[NFTA_DYNSET_SREG_DATA] != NULL) {
 174                 if (!(set->flags & NFT_SET_MAP))
 175                         return -EINVAL;
 176                 if (set->dtype == NFT_DATA_VERDICT)
 177                         return -EOPNOTSUPP;
 178
 179                 priv->sreg_data = nft_parse_register(tb[NFTA_DYNSET_SREG_DATA]);
 180                 err = nft_validate_register_load(priv->sreg_data, set->dlen);
 181                 if (err < 0)
 182                         return err;
 183         } else if (set->flags & NFT_SET_MAP)
 184                 return -EINVAL;
 185
 186         if (tb[NFTA_DYNSET_EXPR] != NULL) {
 187                 if (!(set->flags & NFT_SET_EVAL))
 188                         return -EINVAL;
 189
 190                 priv->expr = nft_expr_init(ctx, tb[NFTA_DYNSET_EXPR]);
 191                 if (IS_ERR(priv->expr))
 192                         return PTR_ERR(priv->expr);
 193
 194                 err = -EOPNOTSUPP;
 195                 if (!(priv->expr->ops->type->flags & NFT_EXPR_STATEFUL))
 196                         goto err1;
 197
 198                 if (priv->expr->ops->type->flags & NFT_EXPR_GC) {
 199                         if (set->flags & NFT_SET_TIMEOUT)
 200                                 goto err1;
 201                         if (!set->ops->gc_init)
 202                                 goto err1;
 203                         set->ops->gc_init(set);
 204                 }
 205         }
 206
 207         nft_set_ext_prepare(&priv->tmpl);
 208         nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_KEY, set->klen);
 209         if (set->flags & NFT_SET_MAP)
 210                 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_DATA, set->dlen);
 211         if (priv->expr != NULL)
 212                 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_EXPR,
 213                                        priv->expr->ops->size);
 214         if (set->flags & NFT_SET_TIMEOUT) {
 215                 if (timeout || set->timeout)
 216                         nft_set_ext_add(&priv->tmpl, NFT_SET_EXT_EXPIRATION);
 217         }
 218
 219         priv->timeout = timeout;
 220
 221         err = nf_tables_bind_set(ctx, set, &priv->binding);
 222         if (err < 0)
 223                 goto err1;
 224
 225         if (set->size == 0)
 226                 set->size = 0xffff;
 227
 228         priv->set = set;
 229         return 0;
 230
 231 err1:
 232         if (priv->expr != NULL)
 233                 nft_expr_destroy(ctx, priv->expr);
 234         return err;
 235 }
 236
 237 static void nft_dynset_deactivate(const struct nft_ctx *ctx,
 238                                   const struct nft_expr *expr,
 239                                   enum nft_trans_phase phase)
 240 {
 241         struct nft_dynset *priv = nft_expr_priv(expr);
 242
 243         nf_tables_deactivate_set(ctx, priv->set, &priv->binding, phase);
 244 }
 245
 246 static void nft_dynset_activate(const struct nft_ctx *ctx,
 247                                 const struct nft_expr *expr)
 248 {
 249         struct nft_dynset *priv = nft_expr_priv(expr);
 250
 251         priv->set->use++;
 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 };