net/netfilter/nft_lookup.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 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/list.h>
  11 #include <linux/rbtree.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
  18 struct nft_lookup {
  19         struct nft_set                  *set;
  20         u8                              sreg;
  21         u8                              dreg;
  22         bool                            invert;
  23         struct nft_set_binding          binding;
  24 };
  25
  26 #ifdef CONFIG_RETPOLINE
  27 bool nft_set_do_lookup(const struct net *net, const struct nft_set *set,
  28                        const u32 *key, const struct nft_set_ext **ext)
  29 {
  30         if (set->ops == &nft_set_hash_fast_type.ops)
  31                 return nft_hash_lookup_fast(net, set, key, ext);
  32         if (set->ops == &nft_set_hash_type.ops)
  33                 return nft_hash_lookup(net, set, key, ext);
  34
  35         if (set->ops == &nft_set_rhash_type.ops)
  36                 return nft_rhash_lookup(net, set, key, ext);
  37
  38         if (set->ops == &nft_set_bitmap_type.ops)
  39                 return nft_bitmap_lookup(net, set, key, ext);
  40
  41         if (set->ops == &nft_set_pipapo_type.ops)
  42                 return nft_pipapo_lookup(net, set, key, ext);
  43 #if defined(CONFIG_X86_64) && !defined(CONFIG_UML)
  44         if (set->ops == &nft_set_pipapo_avx2_type.ops)
  45                 return nft_pipapo_avx2_lookup(net, set, key, ext);
  46 #endif
  47
  48         if (set->ops == &nft_set_rbtree_type.ops)
  49                 return nft_rbtree_lookup(net, set, key, ext);
  50
  51         WARN_ON_ONCE(1);
  52         return set->ops->lookup(net, set, key, ext);
  53 }
  54 EXPORT_SYMBOL_GPL(nft_set_do_lookup);
  55 #endif
  56
  57 void nft_lookup_eval(const struct nft_expr *expr,
  58                      struct nft_regs *regs,
  59                      const struct nft_pktinfo *pkt)
  60 {
  61         const struct nft_lookup *priv = nft_expr_priv(expr);
  62         const struct nft_set *set = priv->set;
  63         const struct nft_set_ext *ext = NULL;
  64         const struct net *net = nft_net(pkt);
  65         bool found;
  66
  67         found = nft_set_do_lookup(net, set, &regs->data[priv->sreg], &ext) ^
  68                                   priv->invert;
  69         if (!found) {
  70                 ext = nft_set_catchall_lookup(net, set);
  71                 if (!ext) {
  72                         regs->verdict.code = NFT_BREAK;
  73                         return;
  74                 }
  75         }
  76
  77         if (ext) {
  78                 if (set->flags & NFT_SET_MAP)
  79                         nft_data_copy(&regs->data[priv->dreg],
  80                                       nft_set_ext_data(ext), set->dlen);
  81
  82                 nft_set_elem_update_expr(ext, regs, pkt);
  83         }
  84 }
  85
  86 static const struct nla_policy nft_lookup_policy[NFTA_LOOKUP_MAX + 1] = {
  87         [NFTA_LOOKUP_SET]       = { .type = NLA_STRING,
  88                                     .len = NFT_SET_MAXNAMELEN - 1 },
  89         [NFTA_LOOKUP_SET_ID]    = { .type = NLA_U32 },
  90         [NFTA_LOOKUP_SREG]      = { .type = NLA_U32 },
  91         [NFTA_LOOKUP_DREG]      = { .type = NLA_U32 },
  92         [NFTA_LOOKUP_FLAGS]     = { .type = NLA_U32 },
  93 };
  94
  95 static int nft_lookup_init(const struct nft_ctx *ctx,
  96                            const struct nft_expr *expr,
  97                            const struct nlattr * const tb[])
  98 {
  99         struct nft_lookup *priv = nft_expr_priv(expr);
 100         u8 genmask = nft_genmask_next(ctx->net);
 101         struct nft_set *set;
 102         u32 flags;
 103         int err;
 104
 105         if (tb[NFTA_LOOKUP_SET] == NULL ||
 106             tb[NFTA_LOOKUP_SREG] == NULL)
 107                 return -EINVAL;
 108
 109         set = nft_set_lookup_global(ctx->net, ctx->table, tb[NFTA_LOOKUP_SET],
 110                                     tb[NFTA_LOOKUP_SET_ID], genmask);
 111         if (IS_ERR(set))
 112                 return PTR_ERR(set);
 113
 114         err = nft_parse_register_load(tb[NFTA_LOOKUP_SREG], &priv->sreg,
 115                                       set->klen);
 116         if (err < 0)
 117                 return err;
 118
 119         if (tb[NFTA_LOOKUP_FLAGS]) {
 120                 flags = ntohl(nla_get_be32(tb[NFTA_LOOKUP_FLAGS]));
 121
 122                 if (flags & ~NFT_LOOKUP_F_INV)
 123                         return -EINVAL;
 124
 125                 if (flags & NFT_LOOKUP_F_INV) {
 126                         if (set->flags & NFT_SET_MAP)
 127                                 return -EINVAL;
 128                         priv->invert = true;
 129                 }
 130         }
 131
 132         if (tb[NFTA_LOOKUP_DREG] != NULL) {
 133                 if (priv->invert)
 134                         return -EINVAL;
 135                 if (!(set->flags & NFT_SET_MAP))
 136                         return -EINVAL;
 137
 138                 err = nft_parse_register_store(ctx, tb[NFTA_LOOKUP_DREG],
 139                                                &priv->dreg, NULL, set->dtype,
 140                                                set->dlen);
 141                 if (err < 0)
 142                         return err;
 143         } else if (set->flags & NFT_SET_MAP)
 144                 return -EINVAL;
 145
 146         priv->binding.flags = set->flags & NFT_SET_MAP;
 147
 148         err = nf_tables_bind_set(ctx, set, &priv->binding);
 149         if (err < 0)
 150                 return err;
 151
 152         priv->set = set;
 153         return 0;
 154 }
 155
 156 static void nft_lookup_deactivate(const struct nft_ctx *ctx,
 157                                   const struct nft_expr *expr,
 158                                   enum nft_trans_phase phase)
 159 {
 160         struct nft_lookup *priv = nft_expr_priv(expr);
 161
 162         nf_tables_deactivate_set(ctx, priv->set, &priv->binding, phase);
 163 }
 164
 165 static void nft_lookup_activate(const struct nft_ctx *ctx,
 166                                 const struct nft_expr *expr)
 167 {
 168         struct nft_lookup *priv = nft_expr_priv(expr);
 169
 170         nf_tables_activate_set(ctx, priv->set);
 171 }
 172
 173 static void nft_lookup_destroy(const struct nft_ctx *ctx,
 174                                const struct nft_expr *expr)
 175 {
 176         struct nft_lookup *priv = nft_expr_priv(expr);
 177
 178         nf_tables_destroy_set(ctx, priv->set);
 179 }
 180
 181 static int nft_lookup_dump(struct sk_buff *skb,
 182                            const struct nft_expr *expr, bool reset)
 183 {
 184         const struct nft_lookup *priv = nft_expr_priv(expr);
 185         u32 flags = priv->invert ? NFT_LOOKUP_F_INV : 0;
 186
 187         if (nla_put_string(skb, NFTA_LOOKUP_SET, priv->set->name))
 188                 goto nla_put_failure;
 189         if (nft_dump_register(skb, NFTA_LOOKUP_SREG, priv->sreg))
 190                 goto nla_put_failure;
 191         if (priv->set->flags & NFT_SET_MAP)
 192                 if (nft_dump_register(skb, NFTA_LOOKUP_DREG, priv->dreg))
 193                         goto nla_put_failure;
 194         if (nla_put_be32(skb, NFTA_LOOKUP_FLAGS, htonl(flags)))
 195                 goto nla_put_failure;
 196         return 0;
 197
 198 nla_put_failure:
 199         return -1;
 200 }
 201
 202 static int nft_lookup_validate(const struct nft_ctx *ctx,
 203                                const struct nft_expr *expr,
 204                                const struct nft_data **d)
 205 {
 206         const struct nft_lookup *priv = nft_expr_priv(expr);
 207         struct nft_set_iter iter;
 208
 209         if (!(priv->set->flags & NFT_SET_MAP) ||
 210             priv->set->dtype != NFT_DATA_VERDICT)
 211                 return 0;
 212
 213         iter.genmask    = nft_genmask_next(ctx->net);
 214         iter.skip       = 0;
 215         iter.count      = 0;
 216         iter.err        = 0;
 217         iter.fn         = nft_setelem_validate;
 218
 219         priv->set->ops->walk(ctx, priv->set, &iter);
 220         if (!iter.err)
 221                 iter.err = nft_set_catchall_validate(ctx, priv->set);
 222
 223         if (iter.err < 0)
 224                 return iter.err;
 225
 226         return 0;
 227 }
 228
 229 static bool nft_lookup_reduce(struct nft_regs_track *track,
 230                               const struct nft_expr *expr)
 231 {
 232         const struct nft_lookup *priv = nft_expr_priv(expr);
 233
 234         if (priv->set->flags & NFT_SET_MAP)
 235                 nft_reg_track_cancel(track, priv->dreg, priv->set->dlen);
 236
 237         return false;
 238 }
 239
 240 static const struct nft_expr_ops nft_lookup_ops = {
 241         .type           = &nft_lookup_type,
 242         .size           = NFT_EXPR_SIZE(sizeof(struct nft_lookup)),
 243         .eval           = nft_lookup_eval,
 244         .init           = nft_lookup_init,
 245         .activate       = nft_lookup_activate,
 246         .deactivate     = nft_lookup_deactivate,
 247         .destroy        = nft_lookup_destroy,
 248         .dump           = nft_lookup_dump,
 249         .validate       = nft_lookup_validate,
 250         .reduce         = nft_lookup_reduce,
 251 };
 252
 253 struct nft_expr_type nft_lookup_type __read_mostly = {
 254         .name           = "lookup",
 255         .ops            = &nft_lookup_ops,
 256         .policy         = nft_lookup_policy,
 257         .maxattr        = NFTA_LOOKUP_MAX,
 258         .owner          = THIS_MODULE,
 259 };