On 03/24, Kamil Zaripov wrote:
Hi everyone,
I trying to make a BPF program that can collect per process per interface statistics of network data consumption. Right now most difficult part for me is RX traffic.
I have tried to find some point in the sk_buff's way up to network stack where I can extract info both about the network interface which captured package and the process that will consume this data but failed. So I have to listen events in several points and somehow merge collected data.
The last point I found at which sk_buff still contains information about network device that captured this sk_buff is netif_receive_skb tracepoint. The first point where I can found information about process is protocol's rcv handlers (like tcp_v4_do_rcv). But I have some questions, to finish my program:
1. It seems that sk_buff modifies during handling, so how can I "match" sk_buff with same data in netif_receive_skb and in tcp_v4_do_rcv?
By "modifies" - do you mean the payload/headers? You can probably use the skb pointer address as a unique identifier to connect across different tracepoints?
2. Maybe there is some good point where I can attach listener and where I can extract both process and interface info for each package?
Nothing pops to my mind. But I think that if you store skbaddr=dev from netif_receive_skb, you should be able to look this up at a later point where you know skb->process association?
Regards Zaripov Kamil.
