net/netfilter/nft_lookup.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Copyright (c) 2009 Patrick McHardy <kaber@trash.net>
0004  *
0005  * Development of this code funded by Astaro AG (http://www.astaro.com/)
0006  */
0007
0008 #include <linux/kernel.h>
0009 #include <linux/init.h>
0010 #include <linux/list.h>
0011 #include <linux/rbtree.h>
0012 #include <linux/netlink.h>
0013 #include <linux/netfilter.h>
0014 #include <linux/netfilter/nf_tables.h>
0015 #include <net/netfilter/nf_tables.h>
0016 #include <net/netfilter/nf_tables_core.h>
0017
0018 struct nft_lookup {
0019     struct nft_set          *set;
0020     u8              sreg;
0021     u8              dreg;
0022     bool                invert;
0023     struct nft_set_binding      binding;
0024 };
0025
0026 #ifdef CONFIG_RETPOLINE
0027 bool nft_set_do_lookup(const struct net *net, const struct nft_set *set,
0028                const u32 *key, const struct nft_set_ext **ext)
0029 {
0030     if (set->ops == &nft_set_hash_fast_type.ops)
0031         return nft_hash_lookup_fast(net, set, key, ext);
0032     if (set->ops == &nft_set_hash_type.ops)
0033         return nft_hash_lookup(net, set, key, ext);
0034
0035     if (set->ops == &nft_set_rhash_type.ops)
0036         return nft_rhash_lookup(net, set, key, ext);
0037
0038     if (set->ops == &nft_set_bitmap_type.ops)
0039         return nft_bitmap_lookup(net, set, key, ext);
0040
0041     if (set->ops == &nft_set_pipapo_type.ops)
0042         return nft_pipapo_lookup(net, set, key, ext);
0043 #if defined(CONFIG_X86_64) && !defined(CONFIG_UML)
0044     if (set->ops == &nft_set_pipapo_avx2_type.ops)
0045         return nft_pipapo_avx2_lookup(net, set, key, ext);
0046 #endif
0047
0048     if (set->ops == &nft_set_rbtree_type.ops)
0049         return nft_rbtree_lookup(net, set, key, ext);
0050
0051     WARN_ON_ONCE(1);
0052     return set->ops->lookup(net, set, key, ext);
0053 }
0054 EXPORT_SYMBOL_GPL(nft_set_do_lookup);
0055 #endif
0056
0057 void nft_lookup_eval(const struct nft_expr *expr,
0058              struct nft_regs *regs,
0059              const struct nft_pktinfo *pkt)
0060 {
0061     const struct nft_lookup *priv = nft_expr_priv(expr);
0062     const struct nft_set *set = priv->set;
0063     const struct nft_set_ext *ext = NULL;
0064     const struct net *net = nft_net(pkt);
0065     bool found;
0066
0067     found = nft_set_do_lookup(net, set, &regs->data[priv->sreg], &ext) ^
0068                   priv->invert;
0069     if (!found) {
0070         ext = nft_set_catchall_lookup(net, set);
0071         if (!ext) {
0072             regs->verdict.code = NFT_BREAK;
0073             return;
0074         }
0075     }
0076
0077     if (ext) {
0078         if (set->flags & NFT_SET_MAP)
0079             nft_data_copy(&regs->data[priv->dreg],
0080                       nft_set_ext_data(ext), set->dlen);
0081
0082         nft_set_elem_update_expr(ext, regs, pkt);
0083     }
0084 }
0085
0086 static const struct nla_policy nft_lookup_policy[NFTA_LOOKUP_MAX + 1] = {
0087     [NFTA_LOOKUP_SET]   = { .type = NLA_STRING,
0088                     .len = NFT_SET_MAXNAMELEN - 1 },
0089     [NFTA_LOOKUP_SET_ID]    = { .type = NLA_U32 },
0090     [NFTA_LOOKUP_SREG]  = { .type = NLA_U32 },
0091     [NFTA_LOOKUP_DREG]  = { .type = NLA_U32 },
0092     [NFTA_LOOKUP_FLAGS] = { .type = NLA_U32 },
0093 };
0094
0095 static int nft_lookup_init(const struct nft_ctx *ctx,
0096                const struct nft_expr *expr,
0097                const struct nlattr * const tb[])
0098 {
0099     struct nft_lookup *priv = nft_expr_priv(expr);
0100     u8 genmask = nft_genmask_next(ctx->net);
0101     struct nft_set *set;
0102     u32 flags;
0103     int err;
0104
0105     if (tb[NFTA_LOOKUP_SET] == NULL ||
0106         tb[NFTA_LOOKUP_SREG] == NULL)
0107         return -EINVAL;
0108
0109     set = nft_set_lookup_global(ctx->net, ctx->table, tb[NFTA_LOOKUP_SET],
0110                     tb[NFTA_LOOKUP_SET_ID], genmask);
0111     if (IS_ERR(set))
0112         return PTR_ERR(set);
0113
0114     err = nft_parse_register_load(tb[NFTA_LOOKUP_SREG], &priv->sreg,
0115                       set->klen);
0116     if (err < 0)
0117         return err;
0118
0119     if (tb[NFTA_LOOKUP_FLAGS]) {
0120         flags = ntohl(nla_get_be32(tb[NFTA_LOOKUP_FLAGS]));
0121
0122         if (flags & ~NFT_LOOKUP_F_INV)
0123             return -EINVAL;
0124
0125         if (flags & NFT_LOOKUP_F_INV) {
0126             if (set->flags & NFT_SET_MAP)
0127                 return -EINVAL;
0128             priv->invert = true;
0129         }
0130     }
0131
0132     if (tb[NFTA_LOOKUP_DREG] != NULL) {
0133         if (priv->invert)
0134             return -EINVAL;
0135         if (!(set->flags & NFT_SET_MAP))
0136             return -EINVAL;
0137
0138         err = nft_parse_register_store(ctx, tb[NFTA_LOOKUP_DREG],
0139                            &priv->dreg, NULL, set->dtype,
0140                            set->dlen);
0141         if (err < 0)
0142             return err;
0143     } else if (set->flags & NFT_SET_MAP)
0144         return -EINVAL;
0145
0146     priv->binding.flags = set->flags & NFT_SET_MAP;
0147
0148     err = nf_tables_bind_set(ctx, set, &priv->binding);
0149     if (err < 0)
0150         return err;
0151
0152     priv->set = set;
0153     return 0;
0154 }
0155
0156 static void nft_lookup_deactivate(const struct nft_ctx *ctx,
0157                   const struct nft_expr *expr,
0158                   enum nft_trans_phase phase)
0159 {
0160     struct nft_lookup *priv = nft_expr_priv(expr);
0161
0162     nf_tables_deactivate_set(ctx, priv->set, &priv->binding, phase);
0163 }
0164
0165 static void nft_lookup_activate(const struct nft_ctx *ctx,
0166                 const struct nft_expr *expr)
0167 {
0168     struct nft_lookup *priv = nft_expr_priv(expr);
0169
0170     priv->set->use++;
0171 }
0172
0173 static void nft_lookup_destroy(const struct nft_ctx *ctx,
0174                    const struct nft_expr *expr)
0175 {
0176     struct nft_lookup *priv = nft_expr_priv(expr);
0177
0178     nf_tables_destroy_set(ctx, priv->set);
0179 }
0180
0181 static int nft_lookup_dump(struct sk_buff *skb, const struct nft_expr *expr)
0182 {
0183     const struct nft_lookup *priv = nft_expr_priv(expr);
0184     u32 flags = priv->invert ? NFT_LOOKUP_F_INV : 0;
0185
0186     if (nla_put_string(skb, NFTA_LOOKUP_SET, priv->set->name))
0187         goto nla_put_failure;
0188     if (nft_dump_register(skb, NFTA_LOOKUP_SREG, priv->sreg))
0189         goto nla_put_failure;
0190     if (priv->set->flags & NFT_SET_MAP)
0191         if (nft_dump_register(skb, NFTA_LOOKUP_DREG, priv->dreg))
0192             goto nla_put_failure;
0193     if (nla_put_be32(skb, NFTA_LOOKUP_FLAGS, htonl(flags)))
0194         goto nla_put_failure;
0195     return 0;
0196
0197 nla_put_failure:
0198     return -1;
0199 }
0200
0201 static int nft_lookup_validate_setelem(const struct nft_ctx *ctx,
0202                        struct nft_set *set,
0203                        const struct nft_set_iter *iter,
0204                        struct nft_set_elem *elem)
0205 {
0206     const struct nft_set_ext *ext = nft_set_elem_ext(set, elem->priv);
0207     struct nft_ctx *pctx = (struct nft_ctx *)ctx;
0208     const struct nft_data *data;
0209     int err;
0210
0211     if (nft_set_ext_exists(ext, NFT_SET_EXT_FLAGS) &&
0212         *nft_set_ext_flags(ext) & NFT_SET_ELEM_INTERVAL_END)
0213         return 0;
0214
0215     data = nft_set_ext_data(ext);
0216     switch (data->verdict.code) {
0217     case NFT_JUMP:
0218     case NFT_GOTO:
0219         pctx->level++;
0220         err = nft_chain_validate(ctx, data->verdict.chain);
0221         if (err < 0)
0222             return err;
0223         pctx->level--;
0224         break;
0225     default:
0226         break;
0227     }
0228
0229     return 0;
0230 }
0231
0232 static int nft_lookup_validate(const struct nft_ctx *ctx,
0233                    const struct nft_expr *expr,
0234                    const struct nft_data **d)
0235 {
0236     const struct nft_lookup *priv = nft_expr_priv(expr);
0237     struct nft_set_iter iter;
0238
0239     if (!(priv->set->flags & NFT_SET_MAP) ||
0240         priv->set->dtype != NFT_DATA_VERDICT)
0241         return 0;
0242
0243     iter.genmask    = nft_genmask_next(ctx->net);
0244     iter.skip   = 0;
0245     iter.count  = 0;
0246     iter.err    = 0;
0247     iter.fn     = nft_lookup_validate_setelem;
0248
0249     priv->set->ops->walk(ctx, priv->set, &iter);
0250     if (iter.err < 0)
0251         return iter.err;
0252
0253     return 0;
0254 }
0255
0256 static bool nft_lookup_reduce(struct nft_regs_track *track,
0257                   const struct nft_expr *expr)
0258 {
0259     const struct nft_lookup *priv = nft_expr_priv(expr);
0260
0261     if (priv->set->flags & NFT_SET_MAP)
0262         nft_reg_track_cancel(track, priv->dreg, priv->set->dlen);
0263
0264     return false;
0265 }
0266
0267 static const struct nft_expr_ops nft_lookup_ops = {
0268     .type       = &nft_lookup_type,
0269     .size       = NFT_EXPR_SIZE(sizeof(struct nft_lookup)),
0270     .eval       = nft_lookup_eval,
0271     .init       = nft_lookup_init,
0272     .activate   = nft_lookup_activate,
0273     .deactivate = nft_lookup_deactivate,
0274     .destroy    = nft_lookup_destroy,
0275     .dump       = nft_lookup_dump,
0276     .validate   = nft_lookup_validate,
0277     .reduce     = nft_lookup_reduce,
0278 };
0279
0280 struct nft_expr_type nft_lookup_type __read_mostly = {
0281     .name       = "lookup",
0282     .ops        = &nft_lookup_ops,
0283     .policy     = nft_lookup_policy,
0284     .maxattr    = NFTA_LOOKUP_MAX,
0285     .owner      = THIS_MODULE,
0286 };