[PATCH net] geneve: maximum value of VNI cannot be used

[PATCH net] geneve: maximum value of VNI cannot be used

[Girish Moodalbail]

Geneve's Virtual Network Identifier (VNI) is 24 bit long, so the range
of values for it would be from 0 to 16777215 (2^24 -1).  However, one
cannot create a geneve device with VNI set to 16777215. This patch fixes
this issue.

Signed-off-by: Girish Moodalbail <girish.moodalbail@oracle.com>
---
 drivers/net/geneve.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
index 745d57ae..8b8565d 100644
--- a/drivers/net/geneve.c
+++ b/drivers/net/geneve.c
@@ -1099,7 +1099,7 @@ static int geneve_validate(struct nlattr *tb[], struct nlattr *data[],
 	if (data[IFLA_GENEVE_ID]) {
 		__u32 vni =  nla_get_u32(data[IFLA_GENEVE_ID]);
 
-		if (vni >= GENEVE_VID_MASK)
+		if (vni >= GENEVE_N_VID)
 			return -ERANGE;
 	}
 
-- 
1.8.3.1

Re: [PATCH net] geneve: maximum value of VNI cannot be used

[David Miller]

From: Girish Moodalbail <girish.moodalbail@oracle.com>
Date: Tue,  8 Aug 2017 17:26:24 -0700

> Geneve's Virtual Network Identifier (VNI) is 24 bit long, so the range
> of values for it would be from 0 to 16777215 (2^24 -1).  However, one
> cannot create a geneve device with VNI set to 16777215. This patch fixes
> this issue.
> 
> Signed-off-by: Girish Moodalbail <girish.moodalbail@oracle.com>

I always worry that someone, somewhere, might be using this in some
way and this will break things.

But I'll apply this for now.

Re: [PATCH net] geneve: maximum value of VNI cannot be used

[Girish Moodalbail]

On 8/9/17 10:41 PM, David Miller wrote:
> From: Girish Moodalbail <girish.moodalbail@oracle.com>
> Date: Tue,  8 Aug 2017 17:26:24 -0700
> 
>> Geneve's Virtual Network Identifier (VNI) is 24 bit long, so the range
>> of values for it would be from 0 to 16777215 (2^24 -1).  However, one
>> cannot create a geneve device with VNI set to 16777215. This patch fixes
>> this issue.
>>
>> Signed-off-by: Girish Moodalbail <girish.moodalbail@oracle.com>
> 
> I always worry that someone, somewhere, might be using this in some
> way and this will break things.
> 
> But I'll apply this for now.
> 
Thanks David. As per the output of 'ip link help geneve', 16777215 is a valid 
value. However, due to incorrect check in the kernel that value was not supported.

$ ip link help geneve |egrep -A1 VNI
Usage: ... geneve id VNI
                   remote ADDR