LXR linux/net/netfilter/nft

   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
  20struct nft_bitwise {
  21        enum nft_registers      sreg:8;
  22        enum nft_registers      dreg:8;
  23        u8                      len;
  24        struct nft_data         mask;
  25        struct nft_data         xor;
  26};
  27
  28static void nft_bitwise_eval(const struct nft_expr *expr,
  29                             struct nft_regs *regs,
  30                             const struct nft_pktinfo *pkt)
  31{
  32        const struct nft_bitwise *priv = nft_expr_priv(expr);
  33        const u32 *src = &regs->data[priv->sreg];
  34        u32 *dst = &regs->data[priv->dreg];
  35        unsigned int i;
  36
  37        for (i = 0; i < DIV_ROUND_UP(priv->len, 4); i++)
  38                dst[i] = (src[i] & priv->mask.data[i]) ^ priv->xor.data[i];
  39}
  40
  41static const struct nla_policy nft_bitwise_policy[NFTA_BITWISE_MAX + 1] = {
  42        [NFTA_BITWISE_SREG]     = { .type = NLA_U32 },
  43        [NFTA_BITWISE_DREG]     = { .type = NLA_U32 },
  44        [NFTA_BITWISE_LEN]      = { .type = NLA_U32 },
  45        [NFTA_BITWISE_MASK]     = { .type = NLA_NESTED },
  46        [NFTA_BITWISE_XOR]      = { .type = NLA_NESTED },
  47};
  48
  49static int nft_bitwise_init(const struct nft_ctx *ctx,
  50                            const struct nft_expr *expr,
  51                            const struct nlattr * const tb[])
  52{
  53        struct nft_bitwise *priv = nft_expr_priv(expr);
  54        struct nft_data_desc d1, d2;
  55        int err;
  56
  57        if (tb[NFTA_BITWISE_SREG] == NULL ||
  58            tb[NFTA_BITWISE_DREG] == NULL ||
  59            tb[NFTA_BITWISE_LEN] == NULL ||
  60            tb[NFTA_BITWISE_MASK] == NULL ||
  61            tb[NFTA_BITWISE_XOR] == NULL)
  62                return -EINVAL;
  63
  64        priv->len  = ntohl(nla_get_be32(tb[NFTA_BITWISE_LEN]));
  65        priv->sreg = nft_parse_register(tb[NFTA_BITWISE_SREG]);
  66        err = nft_validate_register_load(priv->sreg, priv->len);
  67        if (err < 0)
  68                return err;
  69
  70        priv->dreg = nft_parse_register(tb[NFTA_BITWISE_DREG]);
  71        err = nft_validate_register_store(ctx, priv->dreg, NULL,
  72                                          NFT_DATA_VALUE, priv->len);
  73        if (err < 0)
  74                return err;
  75
  76        err = nft_data_init(NULL, &priv->mask, sizeof(priv->mask), &d1,
  77                            tb[NFTA_BITWISE_MASK]);
  78        if (err < 0)
  79                return err;
  80        if (d1.len != priv->len)
  81                return -EINVAL;
  82
  83        err = nft_data_init(NULL, &priv->xor, sizeof(priv->xor), &d2,
  84                            tb[NFTA_BITWISE_XOR]);
  85        if (err < 0)
  86                return err;
  87        if (d2.len != priv->len)
  88                return -EINVAL;
  89
  90        return 0;
  91}
  92
  93static int nft_bitwise_dump(struct sk_buff *skb, const struct nft_expr *expr)
  94{
  95        const struct nft_bitwise *priv = nft_expr_priv(expr);
  96
  97        if (nft_dump_register(skb, NFTA_BITWISE_SREG, priv->sreg))
  98                goto nla_put_failure;
  99        if (nft_dump_register(skb, NFTA_BITWISE_DREG, priv->dreg))
 100                goto nla_put_failure;
 101        if (nla_put_be32(skb, NFTA_BITWISE_LEN, htonl(priv->len)))
 102                goto nla_put_failure;
 103
 104        if (nft_data_dump(skb, NFTA_BITWISE_MASK, &priv->mask,
 105                          NFT_DATA_VALUE, priv->len) < 0)
 106                goto nla_put_failure;
 107
 108        if (nft_data_dump(skb, NFTA_BITWISE_XOR, &priv->xor,
 109                          NFT_DATA_VALUE, priv->len) < 0)
 110                goto nla_put_failure;
 111
 112        return 0;
 113
 114nla_put_failure:
 115        return -1;
 116}
 117
 118static struct nft_expr_type nft_bitwise_type;
 119static const struct nft_expr_ops nft_bitwise_ops = {
 120        .type           = &nft_bitwise_type,
 121        .size           = NFT_EXPR_SIZE(sizeof(struct nft_bitwise)),
 122        .eval           = nft_bitwise_eval,
 123        .init           = nft_bitwise_init,
 124        .dump           = nft_bitwise_dump,
 125};
 126
 127static struct nft_expr_type nft_bitwise_type __read_mostly = {
 128        .name           = "bitwise",
 129        .ops            = &nft_bitwise_ops,
 130        .policy         = nft_bitwise_policy,
 131        .maxattr        = NFTA_BITWISE_MAX,
 132        .owner          = THIS_MODULE,
 133};
 134
 135int __init nft_bitwise_module_init(void)
 136{
 137        return nft_register_expr(&nft_bitwise_type);
 138}
 139
 140void nft_bitwise_module_exit(void)
 141{
 142        nft_unregister_expr(&nft_bitwise_type);
 143}
 144