Subject: Re: [RFC PATCH v2] ipv6: fix handling of blackhole and prohibit routes

From: Nicolas Dichtel <[email-masked]>
Date: Wed, 05 Sep 2012 12:03:37 +0200

Please, forget this patch, it's a wrong version.
Sorry for that.

Regards,
Nicolas

Le 05/09/2012 13:34, Nicolas Dichtel a écrit :
> When adding a blackhole or a prohibit route, they were handling like classic
> routes. Moreover, it was only possible to add this kind of routes by specifying
> an interface.
>
> Bug already reported here:
>    http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=498498
>
> Before the patch:
>    $ ip route add blackhole 2001::1/128
>    RTNETLINK answers: No such device
>    $ ip route add blackhole 2001::1/128 dev eth0
>    $ ip -6 route | grep 2001
>    2001::1 dev eth0  metric 1024
>
> After:
>    $ ip route add blackhole 2001::1/128
>    $ ip -6 route | grep 2001
>    blackhole 2001::1 dev lo  metric 1024  error -22
>
> Signed-off-by: Nicolas Dichtel <[email-masked]>
> ---
>   include/net/ip6_fib.h |  1 +
>   net/ipv6/route.c      | 32 ++++++++++++++++++++++++++++----
>   2 files changed, 29 insertions(+), 4 deletions(-)
>
> diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
> index 0fedbd8..cd64cf3 100644
> --- a/include/net/ip6_fib.h
> +++ b/include/net/ip6_fib.h
> @@ -37,6 +37,7 @@ struct fib6_config {
>   	int		fc_ifindex;
>   	u32		fc_flags;
>   	u32		fc_protocol;
> +	u32		fc_type;	/* only 8 bits are used */
>
>   	struct in6_addr	fc_dst;
>   	struct in6_addr	fc_src;
> diff --git a/net/ipv6/route.c b/net/ipv6/route.c
> index 8e80fd2..5642fb5 100644
> --- a/net/ipv6/route.c
> +++ b/net/ipv6/route.c
> @@ -1463,8 +1463,18 @@ int ip6_route_add(struct fib6_config *cfg)
>   		}
>   		rt->dst.output = ip6_pkt_discard_out;
>   		rt->dst.input = ip6_pkt_discard;
> -		rt->dst.error = -ENETUNREACH;
>   		rt->rt6i_flags = RTF_REJECT|RTF_NONEXTHOP;
> +		switch (cfg->fc_type) {
> +		case RTM_BLACKHOLE:
> +			rt->dst.error = -EINVAL;
> +			break;
> +		case RTM_PROHIBIT:
> +			rt->dst.error = -EACCES;
> +			break;
> +		default:
> +			rt->dst.error = -ENETUNREACH;
> +			break;
> +		}
>   		goto install_route;
>   	}
>
> @@ -2261,8 +2271,11 @@ static int rtm_to_fib6_config(struct sk_buff *skb, struct nlmsghdr *nlh,
>   	cfg->fc_src_len = rtm->rtm_src_len;
>   	cfg->fc_flags = RTF_UP;
>   	cfg->fc_protocol = rtm->rtm_protocol;
> +	cfg->type = rtm->rtm_type;
>
> -	if (rtm->rtm_type == RTN_UNREACHABLE)
> +	if (rtm->rtm_type == RTN_UNREACHABLE ||
> +	    rtm->rtm_type == RTN_BLACKHOLE ||
> +	    rtm->rtm_type == RTN_PROHIBIT)
>   		cfg->fc_flags |= RTF_REJECT;
>
>   	if (rtm->rtm_type == RTN_LOCAL)
> @@ -2391,8 +2404,19 @@ static int rt6_fill_node(struct net *net,
>   	rtm->rtm_table = table;
>   	if (nla_put_u32(skb, RTA_TABLE, table))
>   		goto nla_put_failure;
> -	if (rt->rt6i_flags & RTF_REJECT)
> -		rtm->rtm_type = RTN_UNREACHABLE;
> +	if (rt->rt6i_flags & RTF_REJECT) {
> +		switch (rt->dst.error) {
> +		case -EINVAL:
> +			rtm->rtm_type = RTN_BLACKHOLE;
> +			break;
> +		case -EACCES:
> +			rtm->rtm_type = RTN_PROHIBIT;
> +			break;
> +		default:
> +			rtm->rtm_type = RTN_UNREACHABLE;
> +			break;
> +		}
> +	}
>   	else if (rt->rt6i_flags & RTF_LOCAL)
>   		rtm->rtm_type = RTN_LOCAL;
>   	else if (rt->dst.dev && (rt->dst.dev->flags & IFF_LOOPBACK))
>

-- 
Nicolas DICHTEL
6WIND
R&D Engineer

Tel: +33 1 39 30 92 10
Fax: +33 1 39 30 92 11
[email-masked]
www.6wind.com
Twitter: http://twitter.com/6windsoftware
Join the Multicore Packet Processing Forum: www.multicorepacketprocessing.com

Ce courriel ainsi que toutes les pièces jointes, est uniquement destiné à son ou 
ses destinataires. Il contient des informations confidentielles qui sont la 
propriété de 6WIND. Toute révélation, distribution ou copie des informations 
qu'il contient est strictement interdite. Si vous avez reçu ce message par 
erreur, veuillez immédiatement le signaler à l'émetteur et détruire toutes les 
données reçues.

This e-mail message, including any attachments, is for the sole use of the 
intended recipient(s) and contains information that is confidential and 
proprietary to 6WIND. All unauthorized review, use, disclosure or distribution 
is prohibited. If you are not the intended recipient, please contact the sender 
by reply e-mail and destroy all copies of the original message.