Test of VSC7511 packet mangling bug

gblox.py

# Run "iperf3 -s" on "Computer 1" and "python3 gblox.py 10000 IP_OF_OTHER_COMPUTER_1" on "Computer 2".

# Run wireshark on Computer 2 and watch the packets arriving on port 5201.
# You will see all IP packets except the first in each UDP transmission have mangled 4 bytes
# near the beginning of their data sections. The test program shoud send repeated patterns of
# 0123456789abcdef, so it should be quite easy to spot. The 00 at position 7 and 8 is always
# there, 69 on the second blue line is also always there, while 87 seems to be randomly changing.

import socket
import sys
from math import ceil

l = 1480
ip = "192.168.88.157"
port = 5201

if len(sys.argv) > 1:
  l = int(sys.argv[1])
if len(sys.argv) > 2:
  ip = sys.argv[2]
if len(sys.argv) > 3:
  port = int(sys.argv[3])


s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

payload = ("0123456789ABCDEF" * int(ceil(l/16)))[0:l]
s.sendto(bytes(payload, "ascii"), (ip, port))