Re: [PATCH v4 1/2] netfilter: Introduce new 64-bit helper functions

[Pablo Neira Ayuso <pablo@netfilter.org>]

On Tue, Aug 13, 2019 at 08:38:19PM +0200, Ander Juaristi wrote:
[...]
> diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h
> index 9b624566b82d..aa33ada8728a 100644
> --- a/include/net/netfilter/nf_tables.h
> +++ b/include/net/netfilter/nf_tables.h
> @@ -2,6 +2,7 @@
>  #ifndef _NET_NF_TABLES_H
>  #define _NET_NF_TABLES_H
>  
> +#include <asm/unaligned.h>
>  #include <linux/list.h>
>  #include <linux/netfilter.h>
>  #include <linux/netfilter/nfnetlink.h>
> @@ -119,6 +120,16 @@ static inline void nft_reg_store8(u32 *dreg, u8 val)
>  	*(u8 *)dreg = val;
>  }
>  
> +static inline void nft_reg_store64(u32 *dreg, u64 val)
> +{
> +	put_unaligned(val, (u64 *)dreg);
> +}
> +
> +static inline u64 nft_reg_load64(u32 *sreg)
> +{
> +	return get_unaligned((u64 *)sreg);
> +}

Please, add these function definition below _load16() and _store16().
> +
>  static inline u16 nft_reg_load16(u32 *sreg)
>  {
>  	return *(u16 *)sreg;
> diff --git a/net/netfilter/nft_byteorder.c b/net/netfilter/nft_byteorder.c
> index e06318428ea0..a25a222d94c8 100644
> --- a/net/netfilter/nft_byteorder.c
> +++ b/net/netfilter/nft_byteorder.c
> @@ -43,14 +43,14 @@ void nft_byteorder_eval(const struct nft_expr *expr,
>  		switch (priv->op) {
>  		case NFT_BYTEORDER_NTOH:

This is network-to-host byteorder.

>  			for (i = 0; i < priv->len / 8; i++) {
> -				src64 = get_unaligned((u64 *)&src[i]);
> -				put_unaligned_be64(src64, &dst[i]);
> +				src64 = nft_reg_load64(&src[i]);
> +				nft_reg_store64(&dst[i], cpu_to_be64(src64));

This looks inverted, this should be:

				nft_reg_store64(&dst[i], be64_to_cpu(src64));

right?

>  			}
>  			break;
>  		case NFT_BYTEORDER_HTON:

Here, network-to-host byteorder:

>  			for (i = 0; i < priv->len / 8; i++) {
> -				src64 = get_unaligned_be64(&src[i]);
> -				put_unaligned(src64, (u64 *)&dst[i]);
> +				src64 = be64_to_cpu(nft_reg_load64(&src[i]));

and this:

                                src64 = (__force __u64)
                                        cpu_to_be64(nft_reg_load64(&src[i]));

The (__force __u64) just makes 'sparse' happy [1].

[1] https://www.kernel.org/doc/html/v4.12/dev-tools/sparse.html