Implement ProbeAsync for AccessPointDiscoveryAgentOperationsNetlink

[abeltrano]

Type

• Bug fix
• Feature addition
• Feature update
• Documentation
• Build Infrastructure

Side Effects

• Breaking change
• Non-functional change

Goals

• Allow the subsystem to detect pre-existing interfaces when the server starts.

Technical Details

• Implement AccessPointDiscoveryAgentOperationsNetlink::ProbeAsync() using the nl80211 NL80211_CMD_GET_INTERFACE command with the dump flag.
• Add Netlink80211Interface helper class to represent nl80211 interfaces.
• Add helper function CreateNl80211Socket to create a socket which is connected with the nl80211 genl protocol.
• Add helper Netlink::Allocate() function to create a new wrapper with a pre-allocated netlink socket.

Test Results

• All existing and new unit tests pass.

Reviewer Focus

• None

Future Work

• Make use of the ProbeAsync function to populate initial interfaces.
• Implement better error signaling (some void functions just return on error, some non-void functions return empty collections, etc.).

Checklist

• Build target all compiles cleanly.
• clang-format and clang-tidy deltas produced no new output.
• Newly added functions include doxygen-style comment block.