[PATCH net] vxlan: fix incorrect initializer in union vxlan_addr

[PATCH net] vxlan: fix incorrect initializer in union vxlan_addr

[Gerhard Stenzel]

The first initializer in the following

		union vxlan_addr ipa = {
			.sin.sin_addr.s_addr = tip,
			.sa.sa_family = AF_INET,
		};

is optimised away by the compiler, due to the second initializer,
therefore initialising .sin.sin_addr.s_addr always to 0.
This results in netlink messages indicating a L3 miss never contain the
missed IP address. This was observed with GCC 4.8 and 4.9. I do not know 
about previous versions.
The problem affects user space programs relying on an IP address being
sent as part of a netlink message indicating a L3 miss.

Changing
			.sa.sa_family = AF_INET,
to
			.sin.sin_family = AF_INET,
fixes the problem.

     Signed-off-by: Gerhard Stenzel <gerhard.stenzel@de.ibm.com>

---

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 1fb7b37..beb377b 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -1327,7 +1327,7 @@ static int arp_reduce(struct net_device *dev,
struct sk_buff *skb)
  	} else if (vxlan->flags & VXLAN_F_L3MISS) {
  		union vxlan_addr ipa = {
  			.sin.sin_addr.s_addr = tip,
-			.sa.sa_family = AF_INET,
+			.sin.sin_family = AF_INET,
  		};

  		vxlan_ip_miss(dev, &ipa);
@@ -1488,7 +1488,7 @@ static int neigh_reduce(struct net_device *dev,
struct sk_buff *skb)
  	} else if (vxlan->flags & VXLAN_F_L3MISS) {
  		union vxlan_addr ipa = {
  			.sin6.sin6_addr = msg->target,
-			.sa.sa_family = AF_INET6,
+			.sin6.sin6_family = AF_INET6,
  		};

  		vxlan_ip_miss(dev, &ipa);
@@ -1521,7 +1521,7 @@ static bool route_shortcircuit(struct net_device
*dev, struct sk_buff *skb)
  		if (!n && (vxlan->flags & VXLAN_F_L3MISS)) {
  			union vxlan_addr ipa = {
  				.sin.sin_addr.s_addr = pip->daddr,
-				.sa.sa_family = AF_INET,
+				.sin.sin_family = AF_INET,
  			};

  			vxlan_ip_miss(dev, &ipa);
@@ -1542,7 +1542,7 @@ static bool route_shortcircuit(struct net_device
*dev, struct sk_buff *skb)
  		if (!n && (vxlan->flags & VXLAN_F_L3MISS)) {
  			union vxlan_addr ipa = {
  				.sin6.sin6_addr = pip6->daddr,
-				.sa.sa_family = AF_INET6,
+				.sin6.sin6_family = AF_INET6,
  			};

  			vxlan_ip_miss(dev, &ipa);

Re: [PATCH net] vxlan: fix incorrect initializer in union vxlan_addr

[Cong Wang]

On Fri, Aug 15, 2014 at 2:03 AM, Gerhard Stenzel
<gstenzel@linux.vnet.ibm.com> wrote:
>
> The first initializer in the following
>
>                 union vxlan_addr ipa = {
>                         .sin.sin_addr.s_addr = tip,
>                         .sa.sa_family = AF_INET,
>                 };
>
> is optimised away by the compiler, due to the second initializer,
> therefore initialising .sin.sin_addr.s_addr always to 0.
> This results in netlink messages indicating a L3 miss never contain the
> missed IP address. This was observed with GCC 4.8 and 4.9. I do not know
> about previous versions.
> The problem affects user space programs relying on an IP address being
> sent as part of a netlink message indicating a L3 miss.
>
> Changing
>                         .sa.sa_family = AF_INET,
> to
>                         .sin.sin_family = AF_INET,
> fixes the problem.

So GCC can't figure out we are initializing different parts of this
union through
different members... Or maybe we should not use initializer at all.

Anyway,

Acked-by: Cong Wang <cwang@twopensource.com>

Re: [PATCH net] vxlan: fix incorrect initializer in union vxlan_addr

[David Miller]

From: Gerhard Stenzel <gstenzel@linux.vnet.ibm.com>
Date: Fri, 15 Aug 2014 11:03:58 +0200

> 
> The first initializer in the following
> 
> 		union vxlan_addr ipa = {
> 			.sin.sin_addr.s_addr = tip,
> 			.sa.sa_family = AF_INET,
> 		};
> 
> is optimised away by the compiler, due to the second initializer,
> therefore initialising .sin.sin_addr.s_addr always to 0.
> This results in netlink messages indicating a L3 miss never contain
> the
> missed IP address. This was observed with GCC 4.8 and 4.9. I do not
> know about previous versions.
> The problem affects user space programs relying on an IP address being
> sent as part of a netlink message indicating a L3 miss.
> 
> Changing
> 			.sa.sa_family = AF_INET,
> to
> 			.sin.sin_family = AF_INET,
> fixes the problem.
> 
>     Signed-off-by: Gerhard Stenzel <gerhard.stenzel@de.ibm.com>

Your patch was corrupted by your email client, also please do not
indent your signoff.

THanks.

Re: [PATCH net] vxlan: fix incorrect initializer in union vxlan_addr

[Gerhard Stenzel]

Trying again ... 

On 08/18/2014 07:11 PM, David Miller wrote:
...
> 
> Your patch was corrupted by your email client, also please do not
> indent your signoff.
> 
> THanks.
> 


The first initializer in the following

        union vxlan_addr ipa = {
            .sin.sin_addr.s_addr = tip,
            .sa.sa_family = AF_INET,
        };

is optimised away by the compiler, due to the second initializer,
therefore initialising .sin.sin_addr.s_addr always to 0.
This results in netlink messages indicating a L3 miss never contain the
missed IP address. This was observed with GCC 4.8 and 4.9. I do not know about previous versions.
The problem affects user space programs relying on an IP address being
sent as part of a netlink message indicating a L3 miss.

Changing
            .sa.sa_family = AF_INET,
to
            .sin.sin_family = AF_INET,
fixes the problem.

Signed-off-by: Gerhard Stenzel <gerhard.stenzel@de.ibm.com>

--- 

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 1fb7b37..beb377b 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -1327,7 +1327,7 @@ static int arp_reduce(struct net_device *dev, struct sk_buff *skb)
 	} else if (vxlan->flags & VXLAN_F_L3MISS) {
 		union vxlan_addr ipa = {
 			.sin.sin_addr.s_addr = tip,
-			.sa.sa_family = AF_INET,
+			.sin.sin_family = AF_INET,
 		};
 
 		vxlan_ip_miss(dev, &ipa);
@@ -1488,7 +1488,7 @@ static int neigh_reduce(struct net_device *dev, struct sk_buff *skb)
 	} else if (vxlan->flags & VXLAN_F_L3MISS) {
 		union vxlan_addr ipa = {
 			.sin6.sin6_addr = msg->target,
-			.sa.sa_family = AF_INET6,
+			.sin6.sin6_family = AF_INET6,
 		};
 
 		vxlan_ip_miss(dev, &ipa);
@@ -1521,7 +1521,7 @@ static bool route_shortcircuit(struct net_device *dev, struct sk_buff *skb)
 		if (!n && (vxlan->flags & VXLAN_F_L3MISS)) {
 			union vxlan_addr ipa = {
 				.sin.sin_addr.s_addr = pip->daddr,
-				.sa.sa_family = AF_INET,
+				.sin.sin_family = AF_INET,
 			};
 
 			vxlan_ip_miss(dev, &ipa);
@@ -1542,7 +1542,7 @@ static bool route_shortcircuit(struct net_device *dev, struct sk_buff *skb)
 		if (!n && (vxlan->flags & VXLAN_F_L3MISS)) {
 			union vxlan_addr ipa = {
 				.sin6.sin6_addr = pip6->daddr,
-				.sa.sa_family = AF_INET6,
+				.sin6.sin6_family = AF_INET6,
 			};
 
 			vxlan_ip_miss(dev, &ipa);

Re: [PATCH net] vxlan: fix incorrect initializer in union vxlan_addr

[David Miller]

From: Gerhard Stenzel <gstenzel@linux.vnet.ibm.com>
Date: Tue, 19 Aug 2014 22:36:43 +0200

> Trying again ... 

This is not the correct way to resubmit a patch properly.

Do not ever submit a new copy of a patch as a reply to a discussion
thread, quoting unrelated material, etc.

Instead, make a new, fresh, mailing list posting as if you were
posting the patch for the first time.  Except you add
"[PATCH v2 net]" or similar to indicate this is a new submission
of the patch.