debug_xdp.py

#!/usr/bin/python3
from bcc import BPF
import time

# --- CONFIGURATION ---
device = "wlo1"  # Your Wi-Fi interface

# --- Kernel Code ---
program = """
int hello_packet(struct xdp_md *ctx) {
    // Print this for EVERY packet, no matter what it is
    bpf_trace_printk("I see a packet! Len: %d\\n", ctx->data_end - ctx->data);
    return XDP_PASS;
}
"""

# --- Python Logic ---
print(f"Loading 'Hello World' XDP on {device}...")
b = BPF(text=program)
fn = b.load_func("hello_packet", BPF.XDP)

# Force SKB (Generic) mode. This simulates XDP in software.
# It is slower but works on almost all hardware.
print("Attaching in SKB/Generic Mode...")
try:
    b.attach_xdp(device, fn, flags=BPF.XDP_FLAGS_SKB_MODE)
except Exception as e:
    print(f"Failed to attach: {e}")
    exit()

print("Running! Watch the logs now.")
print("Run this in another terminal: sudo cat /sys/kernel/debug/tracing/trace_pipe")

try:
    while True:
        time.sleep(1)
except KeyboardInterrupt:
    print("\nDetaching...")
    b.remove_xdp(device, 0)