Revert "DHCP DoS Logger for DHCP DoS Mitigation Feature (#18947)"

[yaqiangz]

This reverts commit b00a8d6.

Why I did it

Revert PR #18947 because below 2 issues, it would block PR check

1. dhcp_dos_logger fail to start due to permission issue

admin@sonic:/usr/lib/systemd/system$ sudo systemctl status dhcp_dos_logger.service
× dhcp_dos_logger.service - Log DHCP rate limit violations
     Loaded: loaded (/lib/systemd/system/dhcp_dos_logger.service; enabled-runtime; preset: enabled)
     Active: failed (Result: exit-code) since Tue 2025-06-03 05:26:49 UTC; 4s ago
   Duration: 1ms
    Process: 9932 ExecStart=/usr/bin/dhcp_dos_logger.py (code=exited, status=203/EXEC)
   Main PID: 9932 (code=exited, status=203/EXEC)

Jun 03 05:26:49 sonic systemd[1]: Started dhcp_dos_logger.service - Log DHCP rate limit violations.
Jun 03 05:26:49 sonic (ogger.py)[9932]: dhcp_dos_logger.service: Failed to locate executable /usr/bin/dhcp_dos_logger.py: Permission denied
Jun 03 05:26:49 sonic (ogger.py)[9932]: dhcp_dos_logger.service: Failed at step EXEC spawning /usr/bin/dhcp_dos_logger.py: Permission denied
Jun 03 05:26:49 sonic systemd[1]: dhcp_dos_logger.service: Main process exited, code=exited, status=203/EXEC
Jun 03 05:26:49 sonic systemd[1]: dhcp_dos_logger.service: Failed with result 'exit-code'.

2. Even if grant permission to this file, it would still fail with below error

admin@sonic:/usr/bin$ sudo chmod 755 dhcp_dos_logger.py 
admin@sonic:/usr/bin$
admin@sonic:/usr/bin$ sudo systemctl restart dhcp_dos_logger.service 
admin@sonic:/usr/bin$ sudo systemctl status dhcp_dos_logger.service 
× dhcp_dos_logger.service - Log DHCP rate limit violations
     Loaded: loaded (/lib/systemd/system/dhcp_dos_logger.service; enabled-runtime; preset: enabled)
     Active: failed (Result: exit-code) since Tue 2025-06-03 05:29:38 UTC; 4s ago
   Duration: 85ms
    Process: 11312 ExecStart=/usr/bin/dhcp_dos_logger.py (code=exited, status=1/FAILURE)
   Main PID: 11312 (code=exited, status=1/FAILURE)

Jun 03 05:29:38 sonic dhcp_dos_logger.py[11312]:     handler()
Jun 03 05:29:38 sonic dhcp_dos_logger.py[11312]:   File "/usr/bin/dhcp_dos_logger.py", line 39, in handler
Jun 03 05:29:38 sonic dhcp_dos_logger.py[11312]:     match = re.search(r'dropped (\d+)', output.stdout)
Jun 03 05:29:38 sonic dhcp_dos_logger.py[11312]:             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Jun 03 05:29:38 sonic dhcp_dos_logger.py[11312]:   File "/usr/lib/python3.11/re/__init__.py", line 176, in search
Jun 03 05:29:38 sonic dhcp_dos_logger.py[11312]:     return _compile(pattern, flags).search(string)
Jun 03 05:29:38 sonic dhcp_dos_logger.py[11312]:            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Jun 03 05:29:38 sonic dhcp_dos_logger.py[11312]: TypeError: cannot use a string pattern on a bytes-like object
Jun 03 05:29:38 sonic systemd[1]: dhcp_dos_logger.service: Main process exited, code=exited, status=1/FAILURE
Jun 03 05:29:38 sonic systemd[1]: dhcp_dos_logger.service: Failed with result 'exit-code'.
admin@sonic:/usr/bin$ 

Work item tracking

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How I did it

Revert PR

How to verify it

Which release branch to backport (provide reason below if selected)

• 202205
• 202211
• 202305
• 202311
• 202405
• 202411
• 202505

Tested branch (Please provide the tested image version)

Description for the changelog

Link to config_db schema for YANG module changes

A picture of a cute animal (not mandatory but encouraged)

[yaqiangz]

/azpw run Azure.sonic-buildimage

[mssonicbld]

/azp run

[azure-pipelines]

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[StormLiangMS]

LGTM