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/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index 779cf95..1563875 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -115,7 +115,10 @@
* @NFTA_CHAIN_HANDLE: numeric handle of the chain (NLA_U64)
* @NFTA_CHAIN_NAME: name of the chain (NLA_STRING)
* @NFTA_CHAIN_HOOK: hook specification for basechains (NLA_NESTED: nft_hook_attributes)
+ * @NFTA_CHAIN_POLICY: numeric policy of the chain (NLA_U32)
+ * @NFTA_CHAIN_USE: number of references to this chain (NLA_U32)
* @NFTA_CHAIN_TYPE: type name of the string (NLA_NUL_STRING)
+ * @NFTA_CHAIN_COUNTERS: counter specification of the chain (NLA_NESTED: nft_counter_attributes)
*/
enum nft_chain_attributes {
NFTA_CHAIN_UNSPEC,
@@ -123,7 +126,10 @@
NFTA_CHAIN_HANDLE,
NFTA_CHAIN_NAME,
NFTA_CHAIN_HOOK,
+ NFTA_CHAIN_POLICY,
+ NFTA_CHAIN_USE,
NFTA_CHAIN_TYPE,
+ NFTA_CHAIN_COUNTERS,
__NFTA_CHAIN_MAX
};
#define NFTA_CHAIN_MAX (__NFTA_CHAIN_MAX - 1)
@@ -135,6 +141,7 @@
* @NFTA_RULE_CHAIN: name of the chain containing the rule (NLA_STRING)
* @NFTA_RULE_HANDLE: numeric handle of the rule (NLA_U64)
* @NFTA_RULE_EXPRESSIONS: list of expressions (NLA_NESTED: nft_expr_attributes)
+ * @NFTA_RULE_COMPAT: compatibility specifications of the rule (NLA_NESTED: nft_rule_compat_attributes)
*/
enum nft_rule_attributes {
NFTA_RULE_UNSPEC,
@@ -142,11 +149,36 @@
NFTA_RULE_CHAIN,
NFTA_RULE_HANDLE,
NFTA_RULE_EXPRESSIONS,
+ NFTA_RULE_COMPAT,
__NFTA_RULE_MAX
};
#define NFTA_RULE_MAX (__NFTA_RULE_MAX - 1)
/**
+ * enum nft_rule_compat_flags - nf_tables rule compat flags
+ *
+ * @NFT_RULE_COMPAT_F_INV: invert the check result
+ */
+enum nft_rule_compat_flags {
+ NFT_RULE_COMPAT_F_INV = (1 << 1),
+ NFT_RULE_COMPAT_F_MASK = NFT_RULE_COMPAT_F_INV,
+};
+
+/**
+ * enum nft_rule_compat_attributes - nf_tables rule compat attributes
+ *
+ * @NFTA_RULE_COMPAT_PROTO: numerice value of handled protocol (NLA_U32)
+ * @NFTA_RULE_COMPAT_FLAGS: bitmask of enum nft_rule_compat_flags (NLA_U32)
+ */
+enum nft_rule_compat_attributes {
+ NFTA_RULE_COMPAT_UNSPEC,
+ NFTA_RULE_COMPAT_PROTO,
+ NFTA_RULE_COMPAT_FLAGS,
+ __NFTA_RULE_COMPAT_MAX
+};
+#define NFTA_RULE_COMPAT_MAX (__NFTA_RULE_COMPAT_MAX - 1)
+
+/**
* enum nft_set_flags - nf_tables set flags
*
* @NFT_SET_ANONYMOUS: name allocation, automatic cleanup on unlink