# find-INetworkServerService_IsServerRunning

> Final-guarantee fallback for the find-INetworkServerService_IsServerRunning preprocessor. Recovers INetworkServerService::IsServerRunning (a virtual function of the CNetworkServerService vtable) in CS2 engine2.dll / libengine2.so by decompiling its known predecessor CNetworkGameClientBase__ProcessNetworking and identifying the virtual call on g_pNetworkServerService. Use this skill only when the deterministic/LLM preprocessor (ida_preprocessor_scripts/find-INetworkServerService_IsServerRunning.py) could not resolve the target. Trigger: INetworkServerService_IsServerRunning

- Skill: `hlnd2t/find-inetworkserverservice-isserverrunning` (Agent Skill)
- Install (CLI): `npx skillmds@latest add hlnd2t/find-inetworkserverservice-isserverrunning`
- Raw SKILL.md: https://api.skillmd.com/api/skills/hlnd2t/find-inetworkserverservice-isserverrunning/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: AI & ML
- Author: HLND2T (https://skillmd.com/u/hlnd2t)
- Updated: 2026-09-22
- Page: https://skillmd.com/skills/hlnd2t/find-inetworkserverservice-isserverrunning

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# Find INetworkServerService_IsServerRunning (final-guarantee fallback)

Recover the virtual function `INetworkServerService::IsServerRunning` in CS2 `engine2.dll` /
`libengine2.so` using IDA Pro MCP tools. This is the **Agent fallback** for the
`find-INetworkServerService_IsServerRunning` skill: it runs only when the preprocessor script returned
failure (almost always a transient LLM error, or the predecessor's call structure moved).

## Realworld Function References

Read the platform-relevant reference YAMLs before searching in IDA. They contain the annotated virtual
call site (`; 0x0E8/0x0F0 = ... = INetworkServerService_IsServerRunning`). Treat their addresses as
reference-build values only; verify against the current binary.

- Windows baseline: `ida_preprocessor_scripts/references/engine/CNetworkGameClientBase__ProcessNetworking.windows.yaml`
- Linux baseline: `ida_preprocessor_scripts/references/engine/CNetworkGameClientBase__ProcessNetworking.linux.yaml`

## Step 1. Load and decompile the predecessor

**ALWAYS** Use SKILL `/get-func-from-yaml` with `func_name=CNetworkGameClientBase__ProcessNetworking` to
obtain its `func_va`. If it returns an error, **STOP** and report to user (this fallback cannot run without
the predecessor).

Decompile it:

```
mcp__ida-pro-mcp__decompile addr="<CNetworkGameClientBase__ProcessNetworking.func_va>"
```

## Step 2. Locate the virtual call to the target

`INetworkServerService::IsServerRunning(this)` is an indirect virtual call on the global
`g_pNetworkServerService`. Anchor by its **semantic fingerprint**, not a fixed offset:

- It is the (single) `call qword ptr [reg + <off>]` where `reg = *g_pNetworkServerService` (load the vtable
  from the global, then call through it).
- It returns a boolean (`al`) that is stored/tested to gate the per-tick client networking processing.

Reference build vtable offsets (verify, do not hardcode):

- Windows: `call qword ptr [rax+0E8h]` -> `vfunc_offset = 0xE8` (232), `vfunc_index = 29`
- Linux: `call qword ptr [rax+0F0h]` -> `vfunc_offset = 0xF0` (240), `vfunc_index = 30`

The vtable offset differs per platform; derive it from the located call instruction on the current binary.

## Step 3. Resolve the vfunc body, generate the signature, and write the YAML

1. From the resolved `vfunc_offset`, read the vtable slot of `CNetworkServerService_vtable` to obtain the
   concrete function address, and rename it to `INetworkServerService_IsServerRunning` with
   `mcp__ida-pro-mcp__rename`.
2. **ALWAYS** Use SKILL `/generate-signature-for-vfuncoffset` for the vfunc at the resolved address/offset
   to obtain a validated `vfunc_sig`.
3. **ALWAYS** Use SKILL `/write-vfunc-as-yaml` with:
   - `func_name`: `INetworkServerService_IsServerRunning`
   - `vtable_name`: `CNetworkServerService`
   - `vfunc_sig`: the validated signature from step 2
   - `vfunc_offset` / `vfunc_index`: the resolved values

## Output YAML filenames

Written beside the binary by the writer skill, one file per platform:

- Windows (`engine2.dll`): `INetworkServerService_IsServerRunning.windows.yaml`
- Linux (`libengine2.so`): `INetworkServerService_IsServerRunning.linux.yaml`

## Failure handling

- If the predecessor `CNetworkGameClientBase__ProcessNetworking` YAML is missing → **STOP** and report to
  user.
- If the target virtual call cannot be located even after inspecting the predecessor → **STOP** and report
  so the user can extend the references.