Nettrace is a new kernel module for network packet capture and tracking.
It can capture packets from common protocol stacks and various points within
the kernel, detect abnormal packets, and print kernel and user-mode stacks
at tracepoints. It is designed to be scalable and to have minimal impact
on system performance.

What can this do?
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1) Packet Capture in kernel network stack

 * Capable of capturing packets at various layers of the kernel network stack,
   such as the link layer (L2), IP layer (L3), UDP/TCP modules (L4), and socket
   layer.

 * Enables network troubleshooting by tracing the path of packets through the
   protocol stack.

2) support saved as pcap file like tcpdump

 * Supports capturing network packets at multiple points in the kernel and saving
   them in PCAP format.

3) insmod nettrace.ko without any parameter, which will print more
   detailed usage in kernel dmesg.