IPv4 Socket Surveillance — Tracing using kprobe, kretprobe and maps with BCC
<p>In my previous <a href="https://www.kungfudev.com/blog/2023/10/14/the-beginning-of-my-ebpf-journey-kprobe-bcc" rel="noopener ugc nofollow" target="_blank">article</a>, I explored the fundamentals of eBPF, a technology enabling interaction with the Linux kernel without altering kernel code. I discussed eBPF’s programmable hooks into the kernel, its event-driven nature, and highlighted its utility in system monitoring through syscall hooking. The article also introduced eBPF programming, emphasizing the ease of integrating eBPF programs within Python scripts using BCC. I touched on a simple <code>kprobe</code> example, setting the stage for a deeper dive. This time, I aim to delve further into <code>kprobe</code> and <code>kretprobe</code>, showcasing the versatility of eBPF <code>maps</code> through practical demonstrations, to illuminate eBPF's power in system monitoring and customization, expanding on our prior explorations.</p>
<h1>The probes siblings: kprobe and kretprobe</h1>
<p>The tools <code>kprobe</code> and <code>kretprobe</code> are probing mechanisms within the eBPF ecosystem. <code>kprobe</code> is used to inspect data at the entry of a <code>kernel</code> function, while <code>kretprobe</code> is used at the function's exit. Together, these tools allow us to monitor, analyze, and debug kernel behaviors by capturing both function arguments and return values. Specifically, <code>kretprobe</code>, in particular, is crucial because it captures the return values, showing the result of kernel function calls. This way, we can get a full picture of how functions behave, helping us to understand the system better.</p>
<p><a href="https://douglasmakey.medium.com/ipv4-socket-surveillance-tracing-using-kprobe-kretprobe-and-maps-with-bcc-e865a7bfcda8"><strong>Click Here</strong></a></p>