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        u32 len;
  56        int err;
  57
  58        if (tb[NFTA_BITWISE_SREG] == NULL ||
  59            tb[NFTA_BITWISE_DREG] == NULL ||
  60            tb[NFTA_BITWISE_LEN] == NULL ||
  61            tb[NFTA_BITWISE_MASK] == NULL ||
  62            tb[NFTA_BITWISE_XOR] == NULL)
  63                return -EINVAL;
  64
  65        err = nft_parse_u32_check(tb[NFTA_BITWISE_LEN], U8_MAX, &len);
  66        if (err < 0)
  67                return err;
  68
  69        priv->len = len;
  70
  71        priv->sreg = nft_parse_register(tb[NFTA_BITWISE_SREG]);
  72        err = nft_validate_register_load(priv->sreg, priv->len);
  73        if (err < 0)
  74                return err;
  75
  76        priv->dreg = nft_parse_register(tb[NFTA_BITWISE_DREG]);
  77        err = nft_validate_register_store(ctx, priv->dreg, NULL,
  78                                          NFT_DATA_VALUE, priv->len);
  79        if (err < 0)
  80                return err;
  81
  82        err = nft_data_init(NULL, &priv->mask, sizeof(priv->mask), &d1,
  83                            tb[NFTA_BITWISE_MASK]);
  84        if (err < 0)
  85                return err;
  86        if (d1.len != priv->len) {
  87                err = -EINVAL;
  88                goto err1;
  89        }
  90
  91        err = nft_data_init(NULL, &priv->xor, sizeof(priv->xor), &d2,
  92                            tb[NFTA_BITWISE_XOR]);
  93        if (err < 0)
  94                goto err1;
  95        if (d2.len != priv->len) {
  96                err = -EINVAL;
  97                goto err2;
  98        }
  99
 100        return 0;
 101err2:
 102        nft_data_release(&priv->xor, d2.type);
 103err1:
 104        nft_data_release(&priv->mask, d1.type);
 105        return err;
 106}
 107
 108static int nft_bitwise_dump(struct sk_buff *skb, const struct nft_expr *expr)
 109{
 110        const struct nft_bitwise *priv = nft_expr_priv(expr);
 111
 112        if (nft_dump_register(skb, NFTA_BITWISE_SREG, priv->sreg))
 113                goto nla_put_failure;
 114        if (nft_dump_register(skb, NFTA_BITWISE_DREG, priv->dreg))
 115                goto nla_put_failure;
 116        if (nla_put_be32(skb, NFTA_BITWISE_LEN, htonl(priv->len)))
 117                goto nla_put_failure;
 118
 119        if (nft_data_dump(skb, NFTA_BITWISE_MASK, &priv->mask,
 120                          NFT_DATA_VALUE, priv->len) < 0)
 121                goto nla_put_failure;
 122
 123        if (nft_data_dump(skb, NFTA_BITWISE_XOR, &priv->xor,
 124                          NFT_DATA_VALUE, priv->len) < 0)
 125                goto nla_put_failure;
 126
 127        return 0;
 128
 129nla_put_failure:
 130        return -1;
 131}
 132
 133static const struct nft_expr_ops nft_bitwise_ops = {
 134        .type           = &nft_bitwise_type,
 135        .size           = NFT_EXPR_SIZE(sizeof(struct nft_bitwise)),
 136        .eval           = nft_bitwise_eval,
 137        .init           = nft_bitwise_init,
 138        .dump           = nft_bitwise_dump,
 139};
 140
 141struct nft_expr_type nft_bitwise_type __read_mostly = {
 142        .name           = "bitwise",
 143        .ops            = &nft_bitwise_ops,
 144        .policy         = nft_bitwise_policy,
 145        .maxattr        = NFTA_BITWISE_MAX,
 146        .owner          = THIS_MODULE,
 147};
 148