net/netfilter/nft_immediate.c

   1 /*
   2  * Copyright (c) 2008-2009 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/module.h>
  14 #include <linux/netlink.h>
  15 #include <linux/netfilter.h>
  16 #include <linux/netfilter/nf_tables.h>
  17 #include <net/netfilter/nf_tables_core.h>
  18 #include <net/netfilter/nf_tables.h>
  19
  20 struct nft_immediate_expr {
  21         struct nft_data         data;
  22         enum nft_registers      dreg:8;
  23         u8                      dlen;
  24 };
  25
  26 static void nft_immediate_eval(const struct nft_expr *expr,
  27                                struct nft_data data[NFT_REG_MAX + 1],
  28                                const struct nft_pktinfo *pkt)
  29 {
  30         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
  31
  32         nft_data_copy(&data[priv->dreg], &priv->data);
  33 }
  34
  35 static const struct nla_policy nft_immediate_policy[NFTA_IMMEDIATE_MAX + 1] = {
  36         [NFTA_IMMEDIATE_DREG]   = { .type = NLA_U32 },
  37         [NFTA_IMMEDIATE_DATA]   = { .type = NLA_NESTED },
  38 };
  39
  40 static int nft_immediate_init(const struct nft_ctx *ctx,
  41                               const struct nft_expr *expr,
  42                               const struct nlattr * const tb[])
  43 {
  44         struct nft_immediate_expr *priv = nft_expr_priv(expr);
  45         struct nft_data_desc desc;
  46         int err;
  47
  48         if (tb[NFTA_IMMEDIATE_DREG] == NULL ||
  49             tb[NFTA_IMMEDIATE_DATA] == NULL)
  50                 return -EINVAL;
  51
  52         priv->dreg = ntohl(nla_get_be32(tb[NFTA_IMMEDIATE_DREG]));
  53         err = nft_validate_output_register(priv->dreg);
  54         if (err < 0)
  55                 return err;
  56
  57         err = nft_data_init(ctx, &priv->data, &desc, tb[NFTA_IMMEDIATE_DATA]);
  58         if (err < 0)
  59                 return err;
  60         priv->dlen = desc.len;
  61
  62         err = nft_validate_data_load(ctx, priv->dreg, &priv->data, desc.type);
  63         if (err < 0)
  64                 goto err1;
  65
  66         return 0;
  67
  68 err1:
  69         nft_data_uninit(&priv->data, desc.type);
  70         return err;
  71 }
  72
  73 static void nft_immediate_destroy(const struct nft_expr *expr)
  74 {
  75         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
  76         return nft_data_uninit(&priv->data, nft_dreg_to_type(priv->dreg));
  77 }
  78
  79 static int nft_immediate_dump(struct sk_buff *skb, const struct nft_expr *expr)
  80 {
  81         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
  82
  83         if (nla_put_be32(skb, NFTA_IMMEDIATE_DREG, htonl(priv->dreg)))
  84                 goto nla_put_failure;
  85
  86         return nft_data_dump(skb, NFTA_IMMEDIATE_DATA, &priv->data,
  87                              nft_dreg_to_type(priv->dreg), priv->dlen);
  88
  89 nla_put_failure:
  90         return -1;
  91 }
  92
  93 static int nft_immediate_validate(const struct nft_ctx *ctx,
  94                                   const struct nft_expr *expr,
  95                                   const struct nft_data **data)
  96 {
  97         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
  98
  99         if (priv->dreg == NFT_REG_VERDICT)
 100                 *data = &priv->data;
 101
 102         return 0;
 103 }
 104
 105 static struct nft_expr_type nft_imm_type;
 106 static const struct nft_expr_ops nft_imm_ops = {
 107         .type           = &nft_imm_type,
 108         .size           = NFT_EXPR_SIZE(sizeof(struct nft_immediate_expr)),
 109         .eval           = nft_immediate_eval,
 110         .init           = nft_immediate_init,
 111         .destroy        = nft_immediate_destroy,
 112         .dump           = nft_immediate_dump,
 113         .validate       = nft_immediate_validate,
 114 };
 115
 116 static struct nft_expr_type nft_imm_type __read_mostly = {
 117         .name           = "immediate",
 118         .ops            = &nft_imm_ops,
 119         .policy         = nft_immediate_policy,
 120         .maxattr        = NFTA_IMMEDIATE_MAX,
 121         .owner          = THIS_MODULE,
 122 };
 123
 124 int __init nft_immediate_module_init(void)
 125 {
 126         return nft_register_expr(&nft_imm_type);
 127 }
 128
 129 void nft_immediate_module_exit(void)
 130 {
 131         nft_unregister_expr(&nft_imm_type);
 132 }