LXR linux/net/netfilter/nft

   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
  21struct 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
  28static 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
  40static 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
  46static 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                if (tb[NFTA_LOOKUP_SET_ID]) {
  61                        set = nf_tables_set_lookup_byid(ctx->net,
  62                                                        tb[NFTA_LOOKUP_SET_ID]);
  63                }
  64                if (IS_ERR(set))
  65                        return PTR_ERR(set);
  66        }
  67
  68        priv->sreg = ntohl(nla_get_be32(tb[NFTA_LOOKUP_SREG]));
  69        err = nft_validate_input_register(priv->sreg);
  70        if (err < 0)
  71                return err;
  72
  73        if (tb[NFTA_LOOKUP_DREG] != NULL) {
  74                if (!(set->flags & NFT_SET_MAP))
  75                        return -EINVAL;
  76
  77                priv->dreg = ntohl(nla_get_be32(tb[NFTA_LOOKUP_DREG]));
  78                err = nft_validate_output_register(priv->dreg);
  79                if (err < 0)
  80                        return err;
  81
  82                if (priv->dreg == NFT_REG_VERDICT) {
  83                        if (set->dtype != NFT_DATA_VERDICT)
  84                                return -EINVAL;
  85                } else if (set->dtype == NFT_DATA_VERDICT)
  86                        return -EINVAL;
  87        } else if (set->flags & NFT_SET_MAP)
  88                return -EINVAL;
  89
  90        err = nf_tables_bind_set(ctx, set, &priv->binding);
  91        if (err < 0)
  92                return err;
  93
  94        priv->set = set;
  95        return 0;
  96}
  97
  98static void nft_lookup_destroy(const struct nft_ctx *ctx,
  99                               const struct nft_expr *expr)
 100{
 101        struct nft_lookup *priv = nft_expr_priv(expr);
 102
 103        nf_tables_unbind_set(ctx, priv->set, &priv->binding);
 104}
 105
 106static int nft_lookup_dump(struct sk_buff *skb, const struct nft_expr *expr)
 107{
 108        const struct nft_lookup *priv = nft_expr_priv(expr);
 109
 110        if (nla_put_string(skb, NFTA_LOOKUP_SET, priv->set->name))
 111                goto nla_put_failure;
 112        if (nla_put_be32(skb, NFTA_LOOKUP_SREG, htonl(priv->sreg)))
 113                goto nla_put_failure;
 114        if (priv->set->flags & NFT_SET_MAP)
 115                if (nla_put_be32(skb, NFTA_LOOKUP_DREG, htonl(priv->dreg)))
 116                        goto nla_put_failure;
 117        return 0;
 118
 119nla_put_failure:
 120        return -1;
 121}
 122
 123static struct nft_expr_type nft_lookup_type;
 124static const struct nft_expr_ops nft_lookup_ops = {
 125        .type           = &nft_lookup_type,
 126        .size           = NFT_EXPR_SIZE(sizeof(struct nft_lookup)),
 127        .eval           = nft_lookup_eval,
 128        .init           = nft_lookup_init,
 129        .destroy        = nft_lookup_destroy,
 130        .dump           = nft_lookup_dump,
 131};
 132
 133static struct nft_expr_type nft_lookup_type __read_mostly = {
 134        .name           = "lookup",
 135        .ops            = &nft_lookup_ops,
 136        .policy         = nft_lookup_policy,
 137        .maxattr        = NFTA_LOOKUP_MAX,
 138        .owner          = THIS_MODULE,
 139};
 140
 141int __init nft_lookup_module_init(void)
 142{
 143        return nft_register_expr(&nft_lookup_type);
 144}
 145
 146void nft_lookup_module_exit(void)
 147{
 148        nft_unregister_expr(&nft_lookup_type);
 149}
 150