Patchwork net: Fix tentative IPv6 address due to DAD looping back

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Submitter Meng, Jilin
Date March 22, 2013, 3:20 a.m.
Message ID <D6EA916C7149064CB4D5C686612478A3183E2D27D1@MX34A.corp.emc.com>
Download mbox | patch
Permalink /patch/229875/
State Rejected
Delegated to: David Miller
Headers show

Comments

Meng, Jilin - March 22, 2013, 3:20 a.m.
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@emc.com>
Signed-off-by: Yinglin Sun <yinglin.sun@emc.com>
Signed-off-by: Lakshmanan Prithviraj <lakshmanan.prithviraj@emc.com>
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YOSHIFUJI Hideaki / 吉藤英明 - March 22, 2013, 3:39 a.m.
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@emc.com>
> Signed-off-by: Yinglin Sun <yinglin.sun@emc.com>
> Signed-off-by: Lakshmanan Prithviraj <lakshmanan.prithviraj@emc.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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Sergei Shtylyov - March 22, 2013, 2:37 p.m.
Hello.

On 22-03-2013 7:20, 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@emc.com>
> Signed-off-by: Yinglin Sun <yinglin.sun@emc.com>
> Signed-off-by: Lakshmanan Prithviraj <lakshmanan.prithviraj@emc.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;

    Empty line after declaration wouldn't hurt.

> +					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]) {

    Don't we have memcmp() in Linux?

WBR, Sergei

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Eric Dumazet - March 22, 2013, 2:47 p.m.
On Fri, 2013-03-22 at 18:37 +0400, Sergei Shtylyov wrote:

>     Don't we have memcmp() in Linux?
> 

Dont use slow memcmp() in this context but fast
ether_addr_equal_64bits()



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Meng, Jilin - April 11, 2013, 3:11 a.m.
Yoshfuji,

Partially you are correct. 
But at least this fix removes the limitation that we must configure the switch for bonding first then host in this case.

-Jilin

-----Original Message-----
From: YOSHIFUJI Hideaki [mailto:yoshfuji@linux-ipv6.org] 
Sent: Friday, March 22, 2013 11:40 AM
To: Meng, Jilin
Cc: davem@davemloft.net; kuznet@ms2.inr.ac.ru; jmorris@namei.org; kaber@trash.net; Sun, Yinglin; Prithviraj, Lakshmanan; netdev@vger.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@emc.com>
> Signed-off-by: Yinglin Sun <yinglin.sun@emc.com>
> Signed-off-by: Lakshmanan Prithviraj <lakshmanan.prithviraj@emc.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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Meng, Jilin - April 11, 2013, 3:13 a.m.
Thanks Sergei for introducing a fast function.

-----Original Message-----
From: netdev-owner@vger.kernel.org [mailto:netdev-owner@vger.kernel.org] On Behalf Of Eric Dumazet

Sent: Friday, March 22, 2013 10:48 PM
To: Sergei Shtylyov
Cc: Meng, Jilin; davem@davemloft.net; kuznet@ms2.inr.ac.ru; jmorris@namei.org; yoshfuji@linux-ipv6.org; kaber@trash.net; Sun, Yinglin; Prithviraj, Lakshmanan; netdev@vger.kernel.org
Subject: Re: [PATCH] net: Fix tentative IPv6 address due to DAD looping back

On Fri, 2013-03-22 at 18:37 +0400, Sergei Shtylyov wrote:

>     Don't we have memcmp() in Linux?

> 


Dont use slow memcmp() in this context but fast
ether_addr_equal_64bits()



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David Miller - April 11, 2013, 3:16 a.m.
From: "Meng, Jilin" <Jilin.Meng@emc.com>
Date: Thu, 11 Apr 2013 03:13:42 +0000

> Thanks Sergei for introducing a fast function.

Do not top post.

Quote the email you are responding to, and then put your response
after the quoted content, not before.
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Patch

--- 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