Hi Nayan, This isn't possible as the switch will be at customer site and ports are high premium real estate. A software solution is required. Thx. On Tue, Aug 16, 2016 at 2:39 AM, Gadre Nayan <gadrenayan@gmail.com> wrote:

If you have multiple ports on your system, you may connect a cable directly between two ports and send packets from one port and receive on another.

On Tue, Aug 16, 2016 at 2:41 PM, Alan Liddell <alan.c.liddell@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@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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On Tuesday 16 August 2016 10:42:13 A.M. IST Bhaskar Upadhyayula wrote:

Hi Alan,

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

Thanks.

Well, if you're truly sampling and not just capturing every packet, then in theory there's a nonzero probability that sending the packet back out, addressed to 127.0.0.1 but otherwise unchanged, will not be captured again and then traverse up the kernel's networking stack as usual. Is this not what you want?

On Tue, Aug 16, 2016 at 2:11 AM, Alan Liddell <alan.c.liddell@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@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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-- --ACL