Problem

When starting bitcoind with -networkactive=0, the node still performs various network activities despite the user explicitly requesting that the P2P network be inactive. This results in unnecessary log messages and network overhead:

• [addrman] Selected IP:PORT from tried - Address manager selections
• [net:error] Could not get best interface for default route - Gateway detection attempts
• [tor] Error connecting to Tor control socket - Tor control connection attempts
• [tor] Not connected to Tor control port - Tor reconnection attempts
• [net] portmap: Could not determine IPv4/IPv6 default gateway - UPnP/NAT-PMP attempts

This defeats the purpose of the -networkactive flag, which is documented as "Enable all P2P network activity (default: 1)".

Steps to Reproduce

1. Start bitcoind with bitcoind.exe -networkactive=0
2. Observe logs - despite the flag being set to disable network activity, addrman selections and network-related errors are logged

Expected Behavior

No network activity should occur when -networkactive=0 is set at startup. The node should remain idle until network is activated via RPC command setnetworkactive true.

Solution

This PR ensures that when networkactive=0, no network initialization or activity occurs by:

1. ThreadOpenConnections (src/net.cpp)

Added a check at the beginning of the main while loop to pause all outbound connection logic when fNetworkActive is false. This prevents:

• Address selection from addrman
• Connection attempts to peers
• Feeler connections
• Block relay connection attempts

This check follows the existing pattern used for DNS seed querying (lines 2345-2349) and uses the same synchronization mechanism (fNetworkActive atomic flag and sleep_for with interruption support).

2. StartMapPort (src/init.cpp)

Made NAT-PMP port mapping startup conditional on -networkactive being true. This prevents:

• Port mapping initialization
• Gateway detection attempts
• Related network errors and log spam

3. StartTorControl (src/init.cpp)

Made Tor control thread startup conditional on -networkactive being true. This prevents:

• Tor control socket connection attempts
• Tor-related error logs
• Unnecessary event loop setup

Testing

The fix has been verified to:

• Compile without errors or warnings
• Follow existing code patterns and conventions used in the same functions
• Use the same argument parsing method as existing code (args.GetBoolArg("-networkactive", true))
• Respect the interruption mechanism used throughout the codebase

Manual Testing

# Start with networkactive=0 - should see no network activity logs
bitcoind -networkactive=0

# Start with networkactive=1 (default) - normal behavior
bitcoind

Affected Code Paths
src/net.cpp: CConnman::ThreadOpenConnections() - Main connection management loop
src/init.cpp Bitcoin Core initialization - MapPort and TorControl startup

Notes
This change is backward compatible - default behavior (networkactive=1) is unchanged
Dynamic network activation via setnetworkactive true RPC will resume ThreadOpenConnections activity
MapPort and TorControl remain stopped if started with networkactive=0 (can be addressed in follow-up if needed for dynamic activation)

Fixes #34190