netfilter: x_tables: add .check_hooks to matches and targets

Add a new .check_hooks interface for checking if the match/target is
used from the validate hook according to its configuration.

Move existing conditional hook check based on the match/target
configuration from .checkentry to .check_hooks for the following
matches/targets:

- addrtype
- devgroup
- physdev
- policy
- set
- TCPMSS
- SET

This is a preparation patch to fix nft_compat, not functional changes
are intended.

Based on patch from Florian Westphal.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/include/linux/netfilter/x_tables.h b/include/linux/netfilter/x_tables.h
index 77c778d84d4c..a81b46af5118 100644
--- a/include/linux/netfilter/x_tables.h
+++ b/include/linux/netfilter/x_tables.h
@@ -146,6 +146,9 @@ struct xt_match {
 	/* Called when user tries to insert an entry of this type. */
 	int (*checkentry)(const struct xt_mtchk_param *);
 
+	/* Called to validate hooks based on the match configuration. */
+	int (*check_hooks)(const struct xt_mtchk_param *);
+
 	/* Called when entry of this type deleted. */
 	void (*destroy)(const struct xt_mtdtor_param *);
 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
@@ -187,6 +190,9 @@ struct xt_target {
 	/* Should return 0 on success or an error code otherwise (-Exxxx). */
 	int (*checkentry)(const struct xt_tgchk_param *);
 
+	/* Called to validate hooks based on the target configuration. */
+	int (*check_hooks)(const struct xt_tgchk_param *);
+
 	/* Called when entry of this type deleted. */
 	void (*destroy)(const struct xt_tgdtor_param *);
 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
@@ -279,8 +285,10 @@ bool xt_find_jump_offset(const unsigned int *offsets,
 
 int xt_check_proc_name(const char *name, unsigned int size);
 
+int xt_check_hooks_match(struct xt_mtchk_param *par);
 int xt_check_match(struct xt_mtchk_param *, unsigned int size, u16 proto,
 		   bool inv_proto);
+int xt_check_hooks_target(struct xt_tgchk_param *par);
 int xt_check_target(struct xt_tgchk_param *, unsigned int size, u16 proto,
 		    bool inv_proto);