netfilter: nf_tables: add compatibility layer for x_tables
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>
diff --git a/net/ipv4/netfilter/nf_tables_ipv4.c b/net/ipv4/netfilter/nf_tables_ipv4.c
index 23525c4..c61cffb 100644
--- a/net/ipv4/netfilter/nf_tables_ipv4.c
+++ b/net/ipv4/netfilter/nf_tables_ipv4.c
@@ -15,6 +15,8 @@
#include <linux/netfilter_ipv4.h>
#include <net/netfilter/nf_tables.h>
#include <net/ip.h>
+#include <net/net_namespace.h>
+#include <net/netfilter/nf_tables_ipv4.h>
static unsigned int nft_ipv4_output(const struct nf_hook_ops *ops,
struct sk_buff *skb,
@@ -22,6 +24,8 @@
const struct net_device *out,
int (*okfn)(struct sk_buff *))
{
+ struct nft_pktinfo pkt;
+
if (unlikely(skb->len < sizeof(struct iphdr) ||
ip_hdr(skb)->ihl < sizeof(struct iphdr) / 4)) {
if (net_ratelimit())
@@ -29,8 +33,9 @@
"packet\n");
return NF_ACCEPT;
}
+ nft_set_pktinfo_ipv4(&pkt, ops, skb, in, out);
- return nft_do_chain(ops, skb, in, out, okfn);
+ return nft_do_chain_pktinfo(&pkt, ops);
}
static struct nft_af_info nft_af_ipv4 __read_mostly = {
@@ -42,6 +47,21 @@
},
};
+
+static unsigned int
+nft_do_chain_ipv4(const struct nf_hook_ops *ops,
+ struct sk_buff *skb,
+ const struct net_device *in,
+ const struct net_device *out,
+ int (*okfn)(struct sk_buff *))
+{
+ struct nft_pktinfo pkt;
+
+ nft_set_pktinfo_ipv4(&pkt, ops, skb, in, out);
+
+ return nft_do_chain_pktinfo(&pkt, ops);
+}
+
static struct nf_chain_type filter_ipv4 = {
.family = NFPROTO_IPV4,
.name = "filter",
@@ -52,11 +72,11 @@
(1 << NF_INET_PRE_ROUTING) |
(1 << NF_INET_POST_ROUTING),
.fn = {
- [NF_INET_LOCAL_IN] = nft_do_chain,
- [NF_INET_LOCAL_OUT] = nft_do_chain,
- [NF_INET_FORWARD] = nft_do_chain,
- [NF_INET_PRE_ROUTING] = nft_do_chain,
- [NF_INET_POST_ROUTING] = nft_do_chain,
+ [NF_INET_LOCAL_IN] = nft_do_chain_ipv4,
+ [NF_INET_LOCAL_OUT] = nft_ipv4_output,
+ [NF_INET_FORWARD] = nft_do_chain_ipv4,
+ [NF_INET_PRE_ROUTING] = nft_do_chain_ipv4,
+ [NF_INET_POST_ROUTING] = nft_do_chain_ipv4,
},
};