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![Pablo Neira Ayuso](/assets/img/avatar_default.png)
This patch adds the x_tables compatibility layer. This allows you to use existing x_tables matches and targets from nf_tables. This compatibility later allows us to use existing matches/targets for features that are still missing in nf_tables. We can progressively replace them with native nf_tables extensions. It also provides the userspace compatibility software that allows you to express the rule-set using the iptables syntax but using the nf_tables kernel components. In order to get this compatibility layer working, I've done the following things: * add NFNL_SUBSYS_NFT_COMPAT: this new nfnetlink subsystem is used to query the x_tables match/target revision, so we don't need to use the native x_table getsockopt interface. * emulate xt structures: this required extending the struct nft_pktinfo to include the fragment offset, which is already obtained from ip[6]_tables and that is used by some matches/targets. * add support for default policy to base chains, required to emulate x_tables. * add NFTA_CHAIN_USE attribute to obtain the number of references to chains, required by x_tables emulation. * add chain packet/byte counters using per-cpu. * support 32-64 bits compat. For historical reasons, this patch includes the following patches that were posted in the netfilter-devel mailing list. From Pablo Neira Ayuso: * nf_tables: add default policy to base chains * netfilter: nf_tables: add NFTA_CHAIN_USE attribute * nf_tables: nft_compat: private data of target and matches in contiguous area * nf_tables: validate hooks for compat match/target * nf_tables: nft_compat: release cached matches/targets * nf_tables: x_tables support as a compile time option * nf_tables: fix alias for xtables over nftables module * nf_tables: add packet and byte counters per chain * nf_tables: fix per-chain counter stats if no counters are passed * nf_tables: don't bump chain stats * nf_tables: add protocol and flags for xtables over nf_tables * nf_tables: add ip[6]t_entry emulation * nf_tables: move specific layer 3 compat code to nf_tables_ipv[4|6] * nf_tables: support 32bits-64bits x_tables compat * nf_tables: fix compilation if CONFIG_COMPAT is disabled From Patrick McHardy: * nf_tables: move policy to struct nft_base_chain * nf_tables: send notifications for base chain policy changes From Alexander Primak: * nf_tables: remove the duplicate NF_INET_LOCAL_OUT From Nicolas Dichtel: * nf_tables: fix compilation when nf-netlink is a module Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
160 lines
4.4 KiB
C
160 lines
4.4 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_data data[NFT_REG_MAX + 1],
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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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struct nft_data *dest = &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 = skb_transport_offset(skb);
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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->data, priv->len) < 0)
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goto err;
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return;
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err:
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data[NFT_REG_VERDICT].verdict = 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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int err;
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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 = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_DREG]));
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err = nft_validate_output_register(priv->dreg);
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if (err < 0)
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return err;
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return nft_validate_data_load(ctx, priv->dreg, NULL, NFT_DATA_VALUE);
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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 (nla_put_be32(skb, NFTA_PAYLOAD_DREG, htonl(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 == 0 || len > FIELD_SIZEOF(struct nft_data, data))
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return ERR_PTR(-EINVAL);
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if (len <= 4 && IS_ALIGNED(offset, len) && 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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