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![Patrick McHardy](/assets/img/avatar_default.png)
Switch the nf_tables registers from 128 bit addressing to 32 bit addressing to support so called concatenations, where multiple values can be concatenated over multiple registers for O(1) exact matches of multiple dimensions using sets. The old register values are mapped to areas of 128 bits for compatibility. When dumping register numbers, values are expressed using the old values if they refer to the beginning of a 128 bit area for compatibility. To support concatenations, register loads of less than a full 32 bit value need to be padded. This mainly affects the payload and exthdr expressions, which both unconditionally zero the last word before copying the data. Userspace fully passes the testsuite using both old and new register addressing. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
157 lines
4.2 KiB
C
157 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];
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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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dest[priv->len / NFT_REG32_SIZE] = 0;
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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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