Re: [RFC 3/3] netfilter: nftables: Return preferably given family expression if any

[Patrick McHardy <kaber@trash.net>]

On Thu, Mar 27, 2014 at 11:19:32AM +0200, Tomasz Bursztyka wrote:
> Currently, when looking up for the proper expression type, what comes
> first is returned. Which might end up to be a non-family tight type.
> Instead, if a specific family type exist, it will be better to return
> this one.

Easier suggestion:

Change nft_register_expr() to appent NFPROTO_UNSPEC to the end of the
list and prepend all others.

> 
> Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>
> ---
>  net/netfilter/nf_tables_api.c | 17 ++++++++++-------
>  1 file changed, 10 insertions(+), 7 deletions(-)
> 
> diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
> index adce01e..83de6c1 100644
> --- a/net/netfilter/nf_tables_api.c
> +++ b/net/netfilter/nf_tables_api.c
> @@ -1117,14 +1117,17 @@ EXPORT_SYMBOL_GPL(nft_unregister_expr);
>  static const struct nft_expr_type *__nft_expr_type_get(u8 family,
>  						       struct nlattr *nla)
>  {
> -	const struct nft_expr_type *type;
> -
> -	list_for_each_entry(type, &nf_tables_expressions, list) {
> -		if (!nla_strcmp(nla, type->name) &&
> -		    (!type->family || type->family == family))
> -			return type;
> +	const struct nft_expr_type *test, *type = NULL;
> +
> +	list_for_each_entry(test, &nf_tables_expressions, list) {
> +		if (!nla_strcmp(nla, test->name)) {
> +			if (test->family == family)
> +				return test;
> +			if (!test->family)
> +				type = test;
> +		}
>  	}
> -	return NULL;
> +	return type;
>  }
>  
>  static const struct nft_expr_type *nft_expr_type_get(u8 family,
> -- 
> 1.8.3.2
> 
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