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_regs *regs,
  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        const struct nft_set_ext *ext;
  35
  36        if (set->ops->lookup(set, &regs->data[priv->sreg], &ext)) {
  37                if (set->flags & NFT_SET_MAP)
  38                        nft_data_copy(&regs->data[priv->dreg],
  39                                      nft_set_ext_data(ext), set->dlen);
  40                return;
  41        }
  42        regs->verdict.code = NFT_BREAK;
  43}
  44
  45static const struct nla_policy nft_lookup_policy[NFTA_LOOKUP_MAX + 1] = {
  46        [NFTA_LOOKUP_SET]       = { .type = NLA_STRING },
  47        [NFTA_LOOKUP_SET_ID]    = { .type = NLA_U32 },
  48        [NFTA_LOOKUP_SREG]      = { .type = NLA_U32 },
  49        [NFTA_LOOKUP_DREG]      = { .type = NLA_U32 },
  50};
  51
  52static int nft_lookup_init(const struct nft_ctx *ctx,
  53                           const struct nft_expr *expr,
  54                           const struct nlattr * const tb[])
  55{
  56        struct nft_lookup *priv = nft_expr_priv(expr);
  57        struct nft_set *set;
  58        int err;
  59
  60        if (tb[NFTA_LOOKUP_SET] == NULL ||
  61            tb[NFTA_LOOKUP_SREG] == NULL)
  62                return -EINVAL;
  63
  64        set = nf_tables_set_lookup(ctx->table, tb[NFTA_LOOKUP_SET]);
  65        if (IS_ERR(set)) {
  66                if (tb[NFTA_LOOKUP_SET_ID]) {
  67                        set = nf_tables_set_lookup_byid(ctx->net,
  68                                                        tb[NFTA_LOOKUP_SET_ID]);
  69                }
  70                if (IS_ERR(set))
  71                        return PTR_ERR(set);
  72        }
  73
  74        if (set->flags & NFT_SET_EVAL)
  75                return -EOPNOTSUPP;
  76
  77        priv->sreg = nft_parse_register(tb[NFTA_LOOKUP_SREG]);
  78        err = nft_validate_register_load(priv->sreg, set->klen);
  79        if (err < 0)
  80                return err;
  81
  82        if (tb[NFTA_LOOKUP_DREG] != NULL) {
  83                if (!(set->flags & NFT_SET_MAP))
  84                        return -EINVAL;
  85
  86                priv->dreg = nft_parse_register(tb[NFTA_LOOKUP_DREG]);
  87                err = nft_validate_register_store(ctx, priv->dreg, NULL,
  88                                                  set->dtype, set->dlen);
  89                if (err < 0)
  90                        return err;
  91        } else if (set->flags & NFT_SET_MAP)
  92                return -EINVAL;
  93
  94        priv->binding.flags = set->flags & NFT_SET_MAP;
  95
  96        err = nf_tables_bind_set(ctx, set, &priv->binding);
  97        if (err < 0)
  98                return err;
  99
 100        priv->set = set;
 101        return 0;
 102}
 103
 104static void nft_lookup_destroy(const struct nft_ctx *ctx,
 105                               const struct nft_expr *expr)
 106{
 107        struct nft_lookup *priv = nft_expr_priv(expr);
 108
 109        nf_tables_unbind_set(ctx, priv->set, &priv->binding);
 110}
 111
 112static int nft_lookup_dump(struct sk_buff *skb, const struct nft_expr *expr)
 113{
 114        const struct nft_lookup *priv = nft_expr_priv(expr);
 115
 116        if (nla_put_string(skb, NFTA_LOOKUP_SET, priv->set->name))
 117                goto nla_put_failure;
 118        if (nft_dump_register(skb, NFTA_LOOKUP_SREG, priv->sreg))
 119                goto nla_put_failure;
 120        if (priv->set->flags & NFT_SET_MAP)
 121                if (nft_dump_register(skb, NFTA_LOOKUP_DREG, priv->dreg))
 122                        goto nla_put_failure;
 123        return 0;
 124
 125nla_put_failure:
 126        return -1;
 127}
 128
 129static struct nft_expr_type nft_lookup_type;
 130static const struct nft_expr_ops nft_lookup_ops = {
 131        .type           = &nft_lookup_type,
 132        .size           = NFT_EXPR_SIZE(sizeof(struct nft_lookup)),
 133        .eval           = nft_lookup_eval,
 134        .init           = nft_lookup_init,
 135        .destroy        = nft_lookup_destroy,
 136        .dump           = nft_lookup_dump,
 137};
 138
 139static struct nft_expr_type nft_lookup_type __read_mostly = {
 140        .name           = "lookup",
 141        .ops            = &nft_lookup_ops,
 142        .policy         = nft_lookup_policy,
 143        .maxattr        = NFTA_LOOKUP_MAX,
 144        .owner          = THIS_MODULE,
 145};
 146
 147int __init nft_lookup_module_init(void)
 148{
 149        return nft_register_expr(&nft_lookup_type);
 150}
 151
 152void nft_lookup_module_exit(void)
 153{
 154        nft_unregister_expr(&nft_lookup_type);
 155}
 156