LXR linux/net/netfilter/nft

   1/*
   2 * Copyright (c) 2008 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.h>
  18// FIXME:
  19#include <net/ipv6.h>
  20
  21struct nft_exthdr {
  22        u8                      type;
  23        u8                      offset;
  24        u8                      len;
  25        enum nft_registers      dreg:8;
  26};
  27
  28static void nft_exthdr_eval(const struct nft_expr *expr,
  29                            struct nft_regs *regs,
  30                            const struct nft_pktinfo *pkt)
  31{
  32        struct nft_exthdr *priv = nft_expr_priv(expr);
  33        u32 *dest = &regs->data[priv->dreg];
  34        unsigned int offset = 0;
  35        int err;
  36
  37        err = ipv6_find_hdr(pkt->skb, &offset, priv->type, NULL, NULL);
  38        if (err < 0)
  39                goto err;
  40        offset += priv->offset;
  41
  42        dest[priv->len / NFT_REG32_SIZE] = 0;
  43        if (skb_copy_bits(pkt->skb, offset, dest, priv->len) < 0)
  44                goto err;
  45        return;
  46err:
  47        regs->verdict.code = NFT_BREAK;
  48}
  49
  50static const struct nla_policy nft_exthdr_policy[NFTA_EXTHDR_MAX + 1] = {
  51        [NFTA_EXTHDR_DREG]              = { .type = NLA_U32 },
  52        [NFTA_EXTHDR_TYPE]              = { .type = NLA_U8 },
  53        [NFTA_EXTHDR_OFFSET]            = { .type = NLA_U32 },
  54        [NFTA_EXTHDR_LEN]               = { .type = NLA_U32 },
  55};
  56
  57static int nft_exthdr_init(const struct nft_ctx *ctx,
  58                           const struct nft_expr *expr,
  59                           const struct nlattr * const tb[])
  60{
  61        struct nft_exthdr *priv = nft_expr_priv(expr);
  62        u32 offset, len;
  63
  64        if (tb[NFTA_EXTHDR_DREG] == NULL ||
  65            tb[NFTA_EXTHDR_TYPE] == NULL ||
  66            tb[NFTA_EXTHDR_OFFSET] == NULL ||
  67            tb[NFTA_EXTHDR_LEN] == NULL)
  68                return -EINVAL;
  69
  70        offset = ntohl(nla_get_be32(tb[NFTA_EXTHDR_OFFSET]));
  71        len = ntohl(nla_get_be32(tb[NFTA_EXTHDR_LEN]));
  72
  73        if (offset > U8_MAX || len > U8_MAX)
  74                return -ERANGE;
  75
  76        priv->type   = nla_get_u8(tb[NFTA_EXTHDR_TYPE]);
  77        priv->offset = offset;
  78        priv->len    = len;
  79        priv->dreg   = nft_parse_register(tb[NFTA_EXTHDR_DREG]);
  80
  81        return nft_validate_register_store(ctx, priv->dreg, NULL,
  82                                           NFT_DATA_VALUE, priv->len);
  83}
  84
  85static int nft_exthdr_dump(struct sk_buff *skb, const struct nft_expr *expr)
  86{
  87        const struct nft_exthdr *priv = nft_expr_priv(expr);
  88
  89        if (nft_dump_register(skb, NFTA_EXTHDR_DREG, priv->dreg))
  90                goto nla_put_failure;
  91        if (nla_put_u8(skb, NFTA_EXTHDR_TYPE, priv->type))
  92                goto nla_put_failure;
  93        if (nla_put_be32(skb, NFTA_EXTHDR_OFFSET, htonl(priv->offset)))
  94                goto nla_put_failure;
  95        if (nla_put_be32(skb, NFTA_EXTHDR_LEN, htonl(priv->len)))
  96                goto nla_put_failure;
  97        return 0;
  98
  99nla_put_failure:
 100        return -1;
 101}
 102
 103static struct nft_expr_type nft_exthdr_type;
 104static const struct nft_expr_ops nft_exthdr_ops = {
 105        .type           = &nft_exthdr_type,
 106        .size           = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
 107        .eval           = nft_exthdr_eval,
 108        .init           = nft_exthdr_init,
 109        .dump           = nft_exthdr_dump,
 110};
 111
 112static struct nft_expr_type nft_exthdr_type __read_mostly = {
 113        .name           = "exthdr",
 114        .ops            = &nft_exthdr_ops,
 115        .policy         = nft_exthdr_policy,
 116        .maxattr        = NFTA_EXTHDR_MAX,
 117        .owner          = THIS_MODULE,
 118};
 119
 120static int __init nft_exthdr_module_init(void)
 121{
 122        return nft_register_expr(&nft_exthdr_type);
 123}
 124
 125static void __exit nft_exthdr_module_exit(void)
 126{
 127        nft_unregister_expr(&nft_exthdr_type);
 128}
 129
 130module_init(nft_exthdr_module_init);
 131module_exit(nft_exthdr_module_exit);
 132
 133MODULE_LICENSE("GPL");
 134MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 135MODULE_ALIAS_NFT_EXPR("exthdr");
 136