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![Patrick McHardy](/assets/img/avatar_default.png)
Add helper functions to parse and dump register values in netlink attributes. These helpers will later be changed to take care of translation between the old 128 bit and the new 32 bit register numbers. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
156 lines
4.2 KiB
C
156 lines
4.2 KiB
C
/*
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* Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Development of this code funded by Astaro AG (http://www.astaro.com/)
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/netlink.h>
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#include <linux/netfilter.h>
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#include <linux/netfilter/nf_tables.h>
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#include <net/netfilter/nf_tables_core.h>
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#include <net/netfilter/nf_tables.h>
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static void nft_payload_eval(const struct nft_expr *expr,
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struct nft_regs *regs,
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const struct nft_pktinfo *pkt)
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{
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const struct nft_payload *priv = nft_expr_priv(expr);
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const struct sk_buff *skb = pkt->skb;
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u32 *dest = ®s->data[priv->dreg].data[0];
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int offset;
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switch (priv->base) {
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case NFT_PAYLOAD_LL_HEADER:
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if (!skb_mac_header_was_set(skb))
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goto err;
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offset = skb_mac_header(skb) - skb->data;
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break;
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case NFT_PAYLOAD_NETWORK_HEADER:
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offset = skb_network_offset(skb);
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break;
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case NFT_PAYLOAD_TRANSPORT_HEADER:
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offset = pkt->xt.thoff;
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break;
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default:
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BUG();
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}
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offset += priv->offset;
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if (skb_copy_bits(skb, offset, dest, priv->len) < 0)
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goto err;
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return;
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err:
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regs->verdict.code = NFT_BREAK;
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}
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static const struct nla_policy nft_payload_policy[NFTA_PAYLOAD_MAX + 1] = {
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[NFTA_PAYLOAD_DREG] = { .type = NLA_U32 },
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[NFTA_PAYLOAD_BASE] = { .type = NLA_U32 },
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[NFTA_PAYLOAD_OFFSET] = { .type = NLA_U32 },
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[NFTA_PAYLOAD_LEN] = { .type = NLA_U32 },
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};
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static int nft_payload_init(const struct nft_ctx *ctx,
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const struct nft_expr *expr,
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const struct nlattr * const tb[])
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{
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struct nft_payload *priv = nft_expr_priv(expr);
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priv->base = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_BASE]));
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priv->offset = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_OFFSET]));
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priv->len = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_LEN]));
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priv->dreg = nft_parse_register(tb[NFTA_PAYLOAD_DREG]);
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return nft_validate_register_store(ctx, priv->dreg, NULL,
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NFT_DATA_VALUE, priv->len);
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}
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static int nft_payload_dump(struct sk_buff *skb, const struct nft_expr *expr)
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{
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const struct nft_payload *priv = nft_expr_priv(expr);
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if (nft_dump_register(skb, NFTA_PAYLOAD_DREG, priv->dreg) ||
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nla_put_be32(skb, NFTA_PAYLOAD_BASE, htonl(priv->base)) ||
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nla_put_be32(skb, NFTA_PAYLOAD_OFFSET, htonl(priv->offset)) ||
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nla_put_be32(skb, NFTA_PAYLOAD_LEN, htonl(priv->len)))
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goto nla_put_failure;
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return 0;
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nla_put_failure:
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return -1;
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}
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static struct nft_expr_type nft_payload_type;
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static const struct nft_expr_ops nft_payload_ops = {
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.type = &nft_payload_type,
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.size = NFT_EXPR_SIZE(sizeof(struct nft_payload)),
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.eval = nft_payload_eval,
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.init = nft_payload_init,
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.dump = nft_payload_dump,
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};
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const struct nft_expr_ops nft_payload_fast_ops = {
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.type = &nft_payload_type,
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.size = NFT_EXPR_SIZE(sizeof(struct nft_payload)),
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.eval = nft_payload_eval,
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.init = nft_payload_init,
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.dump = nft_payload_dump,
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};
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static const struct nft_expr_ops *
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nft_payload_select_ops(const struct nft_ctx *ctx,
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const struct nlattr * const tb[])
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{
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enum nft_payload_bases base;
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unsigned int offset, len;
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if (tb[NFTA_PAYLOAD_DREG] == NULL ||
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tb[NFTA_PAYLOAD_BASE] == NULL ||
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tb[NFTA_PAYLOAD_OFFSET] == NULL ||
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tb[NFTA_PAYLOAD_LEN] == NULL)
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return ERR_PTR(-EINVAL);
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base = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_BASE]));
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switch (base) {
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case NFT_PAYLOAD_LL_HEADER:
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case NFT_PAYLOAD_NETWORK_HEADER:
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case NFT_PAYLOAD_TRANSPORT_HEADER:
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break;
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default:
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return ERR_PTR(-EOPNOTSUPP);
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}
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offset = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_OFFSET]));
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len = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_LEN]));
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if (len <= 4 && is_power_of_2(len) && IS_ALIGNED(offset, len) &&
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base != NFT_PAYLOAD_LL_HEADER)
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return &nft_payload_fast_ops;
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else
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return &nft_payload_ops;
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}
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static struct nft_expr_type nft_payload_type __read_mostly = {
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.name = "payload",
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.select_ops = nft_payload_select_ops,
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.policy = nft_payload_policy,
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.maxattr = NFTA_PAYLOAD_MAX,
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.owner = THIS_MODULE,
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};
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int __init nft_payload_module_init(void)
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{
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return nft_register_expr(&nft_payload_type);
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}
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void nft_payload_module_exit(void)
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{
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nft_unregister_expr(&nft_payload_type);
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}
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