Add HID-BPF tutorial and implementation for virtual mouse input modification

- Introduced a comprehensive tutorial in README.md explaining how to fix broken HID devices using eBPF without kernel patches.
- Implemented a userspace program (hid-input-modifier.c) that creates a virtual HID mouse using the uhid interface and sends synthetic mouse events.
- Developed a BPF program (hid-input-modifier.bpf.c) that intercepts HID events and modifies mouse movement data, effectively doubling the X and Y movement.
- Created necessary header files (hid_bpf.h, hid_bpf_defs.h, hid_bpf_helpers.h) to define structures and helper functions for the BPF program.
- Added functionality to find and manage the virtual HID device, ensuring seamless integration with the BPF program.

src/11-bootstrap/README.md

@@ -4,6 +4,8 @@ eBPF (Extended Berkeley Packet Filter) is a powerful network and performance ana
 
 In this tutorial, we will learn how kernel-space and user-space eBPF programs work together. We will also learn how to use the native libbpf to develop user-space programs, package eBPF applications into executable files, and distribute them across different kernel versions.
 
+> The complete source code: <https://github.com/eunomia-bpf/bpf-developer-tutorial/tree/main/src/11-bootstrap>
+
 ## The libbpf Library and Why We Need to Use It
 
 libbpf is a C language library that is distributed with the kernel version to assist in loading and running eBPF programs. It provides a set of C APIs for interacting with the eBPF system, allowing developers to write user-space programs more easily to load and manage eBPF programs. These user-space programs are typically used for system performance analysis, monitoring, or optimization.