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_regs *regs,
  28                                const struct nft_pktinfo *pkt)
  29 {
  30         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
  31
  32         nft_data_copy(&regs->data[priv->dreg], &priv->data, priv->dlen);
  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         err = nft_data_init(ctx, &priv->data, sizeof(priv->data), &desc,
  53                             tb[NFTA_IMMEDIATE_DATA]);
  54         if (err < 0)
  55                 return err;
  56
  57         if (desc.len > U8_MAX)
  58                 return -ERANGE;
  59
  60         priv->dlen = desc.len;
  61
  62         priv->dreg = nft_parse_register(tb[NFTA_IMMEDIATE_DREG]);
  63         err = nft_validate_register_store(ctx, priv->dreg, &priv->data,
  64                                           desc.type, desc.len);
  65         if (err < 0)
  66                 goto err1;
  67
  68         return 0;
  69
  70 err1:
  71         nft_data_uninit(&priv->data, desc.type);
  72         return err;
  73 }
  74
  75 static void nft_immediate_destroy(const struct nft_ctx *ctx,
  76                                   const struct nft_expr *expr)
  77 {
  78         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
  79         return nft_data_uninit(&priv->data, nft_dreg_to_type(priv->dreg));
  80 }
  81
  82 static int nft_immediate_dump(struct sk_buff *skb, const struct nft_expr *expr)
  83 {
  84         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
  85
  86         if (nft_dump_register(skb, NFTA_IMMEDIATE_DREG, priv->dreg))
  87                 goto nla_put_failure;
  88
  89         return nft_data_dump(skb, NFTA_IMMEDIATE_DATA, &priv->data,
  90                              nft_dreg_to_type(priv->dreg), priv->dlen);
  91
  92 nla_put_failure:
  93         return -1;
  94 }
  95
  96 static int nft_immediate_validate(const struct nft_ctx *ctx,
  97                                   const struct nft_expr *expr,
  98                                   const struct nft_data **data)
  99 {
 100         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
 101
 102         if (priv->dreg == NFT_REG_VERDICT)
 103                 *data = &priv->data;
 104
 105         return 0;
 106 }
 107
 108 static struct nft_expr_type nft_imm_type;
 109 static const struct nft_expr_ops nft_imm_ops = {
 110         .type           = &nft_imm_type,
 111         .size           = NFT_EXPR_SIZE(sizeof(struct nft_immediate_expr)),
 112         .eval           = nft_immediate_eval,
 113         .init           = nft_immediate_init,
 114         .destroy        = nft_immediate_destroy,
 115         .dump           = nft_immediate_dump,
 116         .validate       = nft_immediate_validate,
 117 };
 118
 119 static struct nft_expr_type nft_imm_type __read_mostly = {
 120         .name           = "immediate",
 121         .ops            = &nft_imm_ops,
 122         .policy         = nft_immediate_policy,
 123         .maxattr        = NFTA_IMMEDIATE_MAX,
 124         .owner          = THIS_MODULE,
 125 };
 126
 127 int __init nft_immediate_module_init(void)
 128 {
 129         return nft_register_expr(&nft_imm_type);
 130 }
 131
 132 void nft_immediate_module_exit(void)
 133 {
 134         nft_unregister_expr(&nft_imm_type);
 135 }