Re: [PATCH] Allow userspace code to use flag IFA_F_SECONDARY tospecify an ip address to be primary or secondary ip on an interface

From: Vincent Li
Date: Tue Sep 24 2013 - 16:46:50 EST

Ok, I will resend the patch with your suggestions.


On Tue, Sep 24, 2013 at 12:28 PM, David Miller <davem@xxxxxxxxxx> wrote:
> From: Vincent Li <>
> Date: Tue, 24 Sep 2013 11:11:21 -0700
>> the current behavior is when an IP is added to an interface, the primary
>> or secondary attributes is depending on the order of ip added to the interface
>> the first IP will be primary and second, third,... or alias IP will be secondary
>> if the IP subnet matches
>> this patch add the flexiblity to allow user to specify an argument 'primary' or 'secondary'
>> (use 'ip addr add ip/mask primary|secondary dev ethX ' from iproute2 for example) to specify
>> an IP address to be primary or secondary.
>> the reason for this patch is that we have a multi blade cluster platform sharing 'floating management ip'
>> and also that each blade has its own management ip on the management interface, so whichever blade in the
>> cluster becomes primary blade, the 'floating mangaement ip' follows it, and we want any of our traffic
>> originated from the primary blade source from the 'floating management ip' for consistency. but in this
>> case, since the local blade management ip is always the primary ip on the mangaement interface and 'floating
>> management ip' is always secondary, kernel always choose the primary ip as source ip address. thus we would
>> like to add the flexibility in kernel to allow us to specify which ip to be primary or secondary.
>> Signed-off-by: Vincent Li <>
> When submitting a patch, please:
> 1) Specify an appropriate prefix for your subject line, indicating the
> subsystem. "ipv4: " might be appropriate here.
> 2) Format your commit message so that lines do not exceed 80 columns.
> People will read using ASCII text based tools in 80 column
> terminals.
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