netdev - Re: [RFC PATCH bridge 3/5] bridge: Add vlan id to multicast groups

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Date:	Thu, 30 Aug 2012 05:55:33 -0700
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Vlad Yasevich <vyasevic@...hat.com>
Cc:	netdev@...r.kernel.org
Subject: Re: [RFC PATCH bridge 3/5] bridge: Add vlan id to multicast groups

On Thu, 2012-08-23 at 15:29 -0400, Vlad Yasevich wrote:
> Add vlan_id to multicasts groups so that we know which vlan each group belongs
> to and can correctly forward to appropriate vlan.
> 
> Signed-off-by: Vlad Yasevich <vyasevic@...hat.com>
> ---

>  #if IS_ENABLED(CONFIG_IPV6)
>  static inline int __br_ip6_hash(struct net_bridge_mdb_htable *mdb,
> -				const struct in6_addr *ip)
> +				const struct in6_addr *ip,
> +				__u16 vid)
>  {
> -	return jhash2((__force u32 *)ip->s6_addr32, 4, mdb->secret) & (mdb->max - 1);
> +	u32 addr = *(__force u32 *)ip->s6_addr32;
> +	return jhash_2words(addr, vid, mdb->secret) & (mdb->max - 1);
>  }
>  #endif

It seems to me this is wrong.

Hashing only the first 32bits of the IPv6 address is not enough.

We know have ipv6_addr_hash()


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