Re: [PATCH] allow DSCP values in ip rules

[Pavel Balaev <mail@void.so>]

On Wed, Nov 14, 2018 at 05:30:37PM +0300, Pavel Balaev wrote:
> Hello, for now IP rules supports only old TOS values and we cannot use
> DSCP.
> 
> This patch adds support for DSCP values in IP rules:
> 
> $ ip r add default via 192.168.0.6 table test
> $ ip ru add tos 0x80 table test
> $ ip ru
> 0:	from all lookup local 
> 32764:	from all tos CS4 lookup test 
> 32766:	from all lookup main 
> 32767:	from all lookup default 
> $ ip r get fibmatch 8.8.8.9 tos 0x80
> default tos CS4 via 192.168.0.6 dev lan table test
> 
> Signed-off-by: Pavel Balaev <mail@void.so>
> ---
>  net/ipv4/fib_rules.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/ipv4/fib_rules.c b/net/ipv4/fib_rules.c
> index f8eb78d0..7a6c5bfe 100644
> --- a/net/ipv4/fib_rules.c
> +++ b/net/ipv4/fib_rules.c
> @@ -220,7 +220,7 @@ static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
>  	int err = -EINVAL;
>  	struct fib4_rule *rule4 = (struct fib4_rule *) rule;
>  
> -	if (frh->tos & ~IPTOS_TOS_MASK) {
> +	if (frh->tos & ~(IPTOS_TOS_MASK | IPTOS_PREC_MASK)) {
>  		NL_SET_ERR_MSG(extack, "Invalid tos");
>  		goto errout;
>  	}
> -- 
> 2.18.1
> 

This patch adds ability to set newer RFC2597 values, they also presents
in /etc/iproute2/rt_dsfield:

0x28	AF11
0x30	AF12
0x38	AF13
0x48	AF21
...


If one tries to apply this values with iproure2 (ip rule add tos 0x28
...) he will get error from netlink: "Invalid tos" for this moment.