Fix Huawei WLC AP Parsing crash on offline APs

[JaRo5493]

General information

Affected Device: Huawei AC6508 Wireless LAN Controller (WLC)
Software Version: Huawei NMS Version 2.23.00.100.932
CheckMK Version: MSP 2.3.0p12
Issue Summary: The Huawei AC6508 WLC crashes when an offline Access Point (AP) is reported by the controller. The crash occurs due to an out-of-range access attempt on the aps_info2 list when the AP is no longer available, resulting in a system failure.

Bug reports

Operating System:
Debian 12 running Checkmk MSP 2.3.0p12

Steps to Reproduce:

• Run a device discovery on a Huawei AC6508 WLC Controller with disconnected (offline) Access Points.
• Run the attached string_table against the function parse_huawei_wlc_aps
  test.txt

SNMPWalk
Following File contains a Full SNMPWalk which is redacted.
Huawei AC6508 WLC snmpwalk.txt

Crash Report ID:
ID: 48274138-87a8-11ef-a33a-0050568fc548

Proposed changes

Expected Behavior:
When an AP goes offline, CheckMK should handle it gracefully, avoiding any out-of-range memory access. The system should log appropriate warnings or errors rather than attempting to access data from the unavailable AP.

Proposed Patch Change:
The patch modifies the AP handling logic to skip further parsing of AP information when the AP is not available. This prevents out-of-range access and stabilizes the system.

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[JaRo5493]

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