Configure network stack to consume data from TAP device, so that application can operate as if the data was intended to it

Aleksandarf

5/30/24, 5:54 PM

I have two devices communicating, A and B over udp.

In between there is a tap device, where C is connected. In order for C to be able to receive the traffic it needs to set the same ip and mac address as A. (1) This works showing the data intended for A (which is sent from B). However when i also add B (to see the incoming traffic from A) everything stops working.

I assume this is due to conflict of dual pairs of ip configured. I guess that internal routing gets prioritised and. So (1) stops working because the B address also resides on the same machine which isn't producing any traffic.

What can i do about this?

Goal is to be able to get nc -v -u -l <IP_from_A_or_B> 2000 | hd

Surely this scenario isn't unusual when tapping data? Instead of writing promiscuous i would love to be able to solve this with configuration. With or without additional nodes in the network.

0 + 2

tap

linux-networking

nftables

vidarlo

5/30/24, 6:07 PM

This is what promiscuous mode is for. Why do you not want to use that?

Aleksandarf

5/30/24, 6:31 PM

Well i like my application to consume traffic as if it was intended to it (in this case it's about decoding data), so I would like to avoid an additional binary which would operate in promiscuous mode.

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Configure network stack to consume data from TAP device, so that application can operate as if the data was intended to it

Post an answer

Most people don’t grasp that asking a lot of questions unlocks learning and improves interpersonal bonding. In Alison’s studies, for example, though people could accurately recall how many questions had been asked in their conversations, they didn’t intuit the link between questions and liking. Across four studies, in which participants were engaged in conversations themselves or read transcripts of others’ conversations, people tended not to realize that question asking would influence—or had influenced—the level of amity between the conversationalists.