Commit c97d22e6 authored by Pablo Neira Ayuso's avatar Pablo Neira Ayuso

netfilter: nf_tables: add stateful object reference expression

This new expression allows us to refer to existing stateful objects from
rules.
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 173705d9
......@@ -1137,6 +1137,20 @@ enum nft_fwd_attributes {
};
#define NFTA_FWD_MAX (__NFTA_FWD_MAX - 1)
/**
* enum nft_objref_attributes - nf_tables stateful object expression netlink attributes
*
* @NFTA_OBJREF_IMM_TYPE: object type for immediate reference (NLA_U32: nft_register)
* @NFTA_OBJREF_IMM_NAME: object name for immediate reference (NLA_STRING)
*/
enum nft_objref_attributes {
NFTA_OBJREF_UNSPEC,
NFTA_OBJREF_IMM_TYPE,
NFTA_OBJREF_IMM_NAME,
__NFTA_OBJREF_MAX
};
#define NFTA_OBJREF_MAX (__NFTA_OBJREF_MAX - 1)
/**
* enum nft_gen_attributes - nf_tables ruleset generation attributes
*
......
......@@ -551,6 +551,12 @@ config NFT_NAT
This option adds the "nat" expression that you can use to perform
typical Network Address Translation (NAT) packet transformations.
config NFT_OBJREF
tristate "Netfilter nf_tables stateful object reference module"
help
This option adds the "objref" expression that allows you to refer to
stateful objects, such as counters and quotas.
config NFT_QUEUE
depends on NETFILTER_NETLINK_QUEUE
tristate "Netfilter nf_tables queue module"
......
......@@ -88,6 +88,7 @@ obj-$(CONFIG_NFT_NUMGEN) += nft_numgen.o
obj-$(CONFIG_NFT_CT) += nft_ct.o
obj-$(CONFIG_NFT_LIMIT) += nft_limit.o
obj-$(CONFIG_NFT_NAT) += nft_nat.o
obj-$(CONFIG_NFT_OBJREF) += nft_objref.o
obj-$(CONFIG_NFT_QUEUE) += nft_queue.o
obj-$(CONFIG_NFT_QUOTA) += nft_quota.o
obj-$(CONFIG_NFT_REJECT) += nft_reject.o
......
/*
* Copyright (c) 2012-2016 Pablo Neira Ayuso <pablo@netfilter.org>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables.h>
#define nft_objref_priv(expr) *((struct nft_object **)nft_expr_priv(expr))
static void nft_objref_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
struct nft_object *obj = nft_objref_priv(expr);
obj->type->eval(obj, regs, pkt);
}
static int nft_objref_init(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nlattr * const tb[])
{
struct nft_object *obj = nft_objref_priv(expr);
u8 genmask = nft_genmask_next(ctx->net);
u32 objtype;
if (!tb[NFTA_OBJREF_IMM_NAME] ||
!tb[NFTA_OBJREF_IMM_TYPE])
return -EINVAL;
objtype = ntohl(nla_get_be32(tb[NFTA_OBJREF_IMM_TYPE]));
obj = nf_tables_obj_lookup(ctx->table, tb[NFTA_OBJREF_IMM_NAME], objtype,
genmask);
if (IS_ERR(obj))
return -ENOENT;
nft_objref_priv(expr) = obj;
obj->use++;
return 0;
}
static int nft_objref_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
const struct nft_object *obj = nft_objref_priv(expr);
if (nla_put_string(skb, NFTA_OBJREF_IMM_NAME, obj->name) ||
nla_put_be32(skb, NFTA_OBJREF_IMM_TYPE, htonl(obj->type->type)))
goto nla_put_failure;
return 0;
nla_put_failure:
return -1;
}
static void nft_objref_destroy(const struct nft_ctx *ctx,
const struct nft_expr *expr)
{
struct nft_object *obj = nft_objref_priv(expr);
obj->use--;
}
static struct nft_expr_type nft_objref_type;
static const struct nft_expr_ops nft_objref_ops = {
.type = &nft_objref_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_object *)),
.eval = nft_objref_eval,
.init = nft_objref_init,
.destroy = nft_objref_destroy,
.dump = nft_objref_dump,
};
static const struct nla_policy nft_objref_policy[NFTA_OBJREF_MAX + 1] = {
[NFTA_OBJREF_IMM_NAME] = { .type = NLA_STRING },
[NFTA_OBJREF_IMM_TYPE] = { .type = NLA_U32 },
};
static struct nft_expr_type nft_objref_type __read_mostly = {
.name = "objref",
.ops = &nft_objref_ops,
.policy = nft_objref_policy,
.maxattr = NFTA_OBJREF_MAX,
.owner = THIS_MODULE,
};
static int __init nft_objref_module_init(void)
{
return nft_register_expr(&nft_objref_type);
}
static void __exit nft_objref_module_exit(void)
{
nft_unregister_expr(&nft_objref_type);
}
module_init(nft_objref_module_init);
module_exit(nft_objref_module_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
MODULE_ALIAS_NFT_EXPR("objref");
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