net/netfilter/nft_lookup.c

   1 /*
   2  * Copyright (c) 2009 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  * Development of this code funded by Astaro AG (http://www.astaro.com/)
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/init.h>
  13 #include <linux/list.h>
  14 #include <linux/rbtree.h>
  15 #include <linux/netlink.h>
  16 #include <linux/netfilter.h>
  17 #include <linux/netfilter/nf_tables.h>
  18 #include <net/netfilter/nf_tables.h>
  19 #include <net/netfilter/nf_tables_core.h>
  20
  21 struct nft_lookup {
  22         struct nft_set                  *set;
  23         enum nft_registers              sreg:8;
  24         enum nft_registers              dreg:8;
  25         struct nft_set_binding          binding;
  26 };
  27
  28 static void nft_lookup_eval(const struct nft_expr *expr,
  29                             struct nft_data data[NFT_REG_MAX + 1],
  30                             const struct nft_pktinfo *pkt)
  31 {
  32         const struct nft_lookup *priv = nft_expr_priv(expr);
  33         const struct nft_set *set = priv->set;
  34
  35         if (set->ops->lookup(set, &data[priv->sreg], &data[priv->dreg]))
  36                 return;
  37         data[NFT_REG_VERDICT].verdict = NFT_BREAK;
  38 }
  39
  40 static const struct nla_policy nft_lookup_policy[NFTA_LOOKUP_MAX + 1] = {
  41         [NFTA_LOOKUP_SET]       = { .type = NLA_STRING },
  42         [NFTA_LOOKUP_SREG]      = { .type = NLA_U32 },
  43         [NFTA_LOOKUP_DREG]      = { .type = NLA_U32 },
  44 };
  45
  46 static int nft_lookup_init(const struct nft_ctx *ctx,
  47                            const struct nft_expr *expr,
  48                            const struct nlattr * const tb[])
  49 {
  50         struct nft_lookup *priv = nft_expr_priv(expr);
  51         struct nft_set *set;
  52         int err;
  53
  54         if (tb[NFTA_LOOKUP_SET] == NULL ||
  55             tb[NFTA_LOOKUP_SREG] == NULL)
  56                 return -EINVAL;
  57
  58         set = nf_tables_set_lookup(ctx->table, tb[NFTA_LOOKUP_SET]);
  59         if (IS_ERR(set))
  60                 return PTR_ERR(set);
  61
  62         priv->sreg = ntohl(nla_get_be32(tb[NFTA_LOOKUP_SREG]));
  63         err = nft_validate_input_register(priv->sreg);
  64         if (err < 0)
  65                 return err;
  66
  67         if (tb[NFTA_LOOKUP_DREG] != NULL) {
  68                 if (!(set->flags & NFT_SET_MAP))
  69                         return -EINVAL;
  70
  71                 priv->dreg = ntohl(nla_get_be32(tb[NFTA_LOOKUP_DREG]));
  72                 err = nft_validate_output_register(priv->dreg);
  73                 if (err < 0)
  74                         return err;
  75
  76                 if (priv->dreg == NFT_REG_VERDICT) {
  77                         if (set->dtype != NFT_DATA_VERDICT)
  78                                 return -EINVAL;
  79                 } else if (set->dtype == NFT_DATA_VERDICT)
  80                         return -EINVAL;
  81         } else if (set->flags & NFT_SET_MAP)
  82                 return -EINVAL;
  83
  84         err = nf_tables_bind_set(ctx, set, &priv->binding);
  85         if (err < 0)
  86                 return err;
  87
  88         priv->set = set;
  89         return 0;
  90 }
  91
  92 static void nft_lookup_destroy(const struct nft_expr *expr)
  93 {
  94         struct nft_lookup *priv = nft_expr_priv(expr);
  95
  96         nf_tables_unbind_set(NULL, priv->set, &priv->binding);
  97 }
  98
  99 static int nft_lookup_dump(struct sk_buff *skb, const struct nft_expr *expr)
 100 {
 101         const struct nft_lookup *priv = nft_expr_priv(expr);
 102
 103         if (nla_put_string(skb, NFTA_LOOKUP_SET, priv->set->name))
 104                 goto nla_put_failure;
 105         if (nla_put_be32(skb, NFTA_LOOKUP_SREG, htonl(priv->sreg)))
 106                 goto nla_put_failure;
 107         if (priv->set->flags & NFT_SET_MAP)
 108                 if (nla_put_be32(skb, NFTA_LOOKUP_DREG, htonl(priv->dreg)))
 109                         goto nla_put_failure;
 110         return 0;
 111
 112 nla_put_failure:
 113         return -1;
 114 }
 115
 116 static struct nft_expr_type nft_lookup_type;
 117 static const struct nft_expr_ops nft_lookup_ops = {
 118         .type           = &nft_lookup_type,
 119         .size           = NFT_EXPR_SIZE(sizeof(struct nft_lookup)),
 120         .eval           = nft_lookup_eval,
 121         .init           = nft_lookup_init,
 122         .destroy        = nft_lookup_destroy,
 123         .dump           = nft_lookup_dump,
 124 };
 125
 126 static struct nft_expr_type nft_lookup_type __read_mostly = {
 127         .name           = "lookup",
 128         .ops            = &nft_lookup_ops,
 129         .policy         = nft_lookup_policy,
 130         .maxattr        = NFTA_LOOKUP_MAX,
 131         .owner          = THIS_MODULE,
 132 };
 133
 134 int __init nft_lookup_module_init(void)
 135 {
 136         return nft_register_expr(&nft_lookup_type);
 137 }
 138
 139 void nft_lookup_module_exit(void)
 140 {
 141         nft_unregister_expr(&nft_lookup_type);
 142 }