netdev - Re: [PATCH] net: Fix tentative IPv6 address due to DAD looping back

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Message-ID: <1363923575.16608.17.camel@cirrhata>
Date:	Fri, 22 Mar 2013 12:39:35 +0900
From:	YOSHIFUJI Hideaki <yoshfuji@...ux-ipv6.org>
To:	"Meng, Jilin" <Jilin.Meng@....com>
Cc:	"davem@...emloft.net" <davem@...emloft.net>,
	"kuznet@....inr.ac.ru" <kuznet@....inr.ac.ru>,
	"jmorris@...ei.org" <jmorris@...ei.org>,
	"kaber@...sh.net" <kaber@...sh.net>,
	"Sun, Yinglin" <yinglin.sun@....com>,
	"Prithviraj, Lakshmanan" <lakshmanan.prithviraj@....com>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: [PATCH] net: Fix tentative IPv6 address due to DAD looping back

Meng, Jilin wrote:
> we should ignore the looped-back IPv6 DAD packet to avoid configuration failure.
> This occurs when a bonding interface with roundrobin mode is being configured an IPv6 address 
> while the switch side isn't configured bonding/channel yet.
> 
> Signed-off-by: Jilin Meng <jilin.meng@....com>
> Signed-off-by: Yinglin Sun <yinglin.sun@....com>
> Signed-off-by: Lakshmanan Prithviraj <lakshmanan.prithviraj@....com>
> ---
> --- linux/net/ipv6/ndisc.c.orig	2013-03-12 17:16:18.000000000 +0800
> +++ linux/net/ipv6/ndisc.c	2013-03-21 10:37:06.000000000 +0800
> @@ -757,6 +757,24 @@ static void ndisc_recv_ns(struct sk_buff
>  
>  		if (ifp->flags & (IFA_F_TENTATIVE|IFA_F_OPTIMISTIC)) {
>  			if (dad) {
> +				if (dev->type == ARPHRD_ETHER) {
> +					const unsigned char *sadr;
> +					sadr = skb_mac_header(skb);
> +					if (sadr[6] == dev->dev_addr[0] &&
> +					    sadr[7] == dev->dev_addr[1] &&
> +					    sadr[8] == dev->dev_addr[2] &&
> +					    sadr[9] == dev->dev_addr[3] &&
> +					    sadr[10] == dev->dev_addr[4] &&
> +					    sadr[11] == dev->dev_addr[5]) {
> +					/*
> +					 * looped-back to us. This occurs when
> +					 * a bonding interface with roundrobin
> +					 * mode is being configured while the
> +					 * switch side isn't configured yet.
> +					 */
> +						goto out;
> +				}
> +
>  				/*
>  				 * We are colliding with another node
>  				 * who is doing DAD

I would say that it is a configuration error.

--yoshfuji

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