Send packets from userspace program to kernel interface

[Bhaskar Upadhyayula]

Hi Alan,

I am not sure how this will achieve what I want. Can you please
explain a bit more?

Thanks.

On Tue, Aug 16, 2016 at 2:11 AM, Alan Liddell <alan.c.liddell at gmail.com> wrote:
> Would sending the packet back out through the loopback address accomplish
> what you're looking to do?
>
>
> On Aug 16, 2016 7:51 AM, "Bhaskar Upadhyayula" <bu.kernel at gmail.com> wrote:
>>
>> Hello All,
>>
>> Summary:
>> ===
>> If a userspace program has a well crafted packet (ethernet or IPv4 or
>> other protocol packet), is there a way for it to send the packet to
>> kernel's network interface, simulating the behavior that the packet
>> ingress'ed on that interface? Is this possible?
>>
>>
>> Detailed Problem Description:
>> ===
>> I am working on packet sampling feature (sFlow) on OpenSwitch
>> (www.openswitch.net) Network OS. Currently, this OS is supported on
>> few Accton switches that has Broadcom's Trident2 chipset. When we
>> enable packet sampling, the sampled packets are sent to a userspace
>> program, by passing the kernel network stack. This is a problem if the
>> packet was supposed to go up the network stack.
>>
>> I am investigating options to re-send the packet back to kernel
>> interface on which packet arrived on the switch. Hence this question.
>>
>> A colleague suggested looking at Tuntap interfaces. I did a quick
>> research and it did not appear that can be done.
>>
>> Any suggestions or pointers for further reading will be very helpful.
>>
>>
>> Thanks.
>>
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