Networking And Public Variables

Networking And Public Variables

Arma 2 OA networking here is built around public variables, public-variable event handlers and wrapper functions that dispatch named PVF commands.

Central PVF Registration

Common/Init/Init_PublicVariables.sqf creates two command lists:

Server PVF commands:

• RequestVehicleLock
• RequestOnUnitKilled
• RequestChangeScore
• RequestCommanderVote
• RequestNewCommander
• RequestStructure
• RequestDefense
• RequestJoin
• RequestMHQRepair
• RequestSpecial
• RequestTeamUpdate
• RequestUpgrade
• RequestAutoWallConstructinChange

Client PVF commands:

• AllCampsCaptured
• AwardBounty
• AwardBountyPlayer
• CampCaptured
• ChangeScore
• HandleSpecial
• LocalizeMessage
• SetTask
• SetVehicleLock
• TownCaptured
• SetMHQLock
• Available
• RequestBaseArea
• NukeIncoming

Each command is compiled into either SRVFNC... or CLTFNC..., and WFBE_PVF_<Command> receives an event handler that passes payloads to Server_HandlePVF or Client_HandlePVF.

Network Helper Layer

• Common_SendToServer: sends a server PVF; uses optimized publicVariableServer outside vanilla mode.
• Common_SendToClients: broadcasts client PVF to all clients.
• Common_SendToClient: targets one client where supported.

These wrappers are preferred over hand-coded public variable dispatch for new features.

Direct Public Variables

Some systems use explicit public-variable channels outside the generic PVF list. The canonical inventory is Public variable channel index, including registered WFBE_PVF_* commands, direct channels, source anchors and notable findings.

Why this matters: direct channels such as ATTACK_WAVE_INIT, supply mission PVs, side-supply temp variables, MASH marker channels, HQ marker/state broadcasts, AntiStack compensation, server FPS and AFK kick are not automatically covered by a future PVF dispatcher fix. Treat them as separate review targets when hardening the network layer.

Direct PV Hardening Order

1. Fix PVF dispatcher command resolution first (DR-1), because that closes arbitrary command-string execution.
2. Harden registered high-impact handlers next: construction, upgrades, score, vehicle lock, commander/team changes.
3. Review the direct channels above separately, because they will not be protected by a WFBE_PVF_* allow-list.
4. Design BattlEye publicvariable.txt from both lists: registered WFBE_PVF_* channels plus explicit direct channels such as kickAFK, supply mission PVs, day/night, HQ markers, attack waves and AntiStack compensation.

Replay/JIP rule of thumb: late players receive retained object/global state and the next heartbeat, not a replay of old publicVariable events. For revived event-only channels such as MASH marker relays, add a server-held list and explicit JIP re-send plan rather than assuming event replay.

Safety Notes

• Keep payloads small and structured; Arma 2 public-variable traffic can be expensive.
• Prefer server authority for state changes. Client scripts should request, not mutate, team/base/economy state directly.
• When adding a PVF command, update both the registration list and the target Client/PVFunctions or Server/PVFunctions file.
• Hosted-server paths often call the handler locally in addition to broadcasting. Preserve those branches when modernizing code.

PVF Dispatch Internals

Claude independently deep-read the dispatch path and confirmed these runtime details. Paths are relative to Missions/[55-2hc]warfarev2_073v48co.chernarus/.

One PV Variable Per Command

Common/Init/Init_PublicVariables.sqf:43-51 creates one public-variable name per command, such as WFBE_PVF_RequestJoin and WFBE_PVF_TownCaptured, each with its own addPublicVariableEventHandler. This is not one numeric multiplexed protocol channel. Client handlers register under if (!isServer || local player); server handlers register under if (isServer).

Client-Side Index-0 Routing

Client/Functions/Client_HandlePVF.sqf uses payload element 0 as the destination filter:

Element 0	Client behavior
nil	Run on all clients.
SIDE	Run only if sideJoined == destination.
STRING	Run only if getPlayerUID player == destination.

The actual function name comes from element 1 (CLTFNC<Command>) and is executed with _parameters Spawn (Call Compile _script). Server/Functions/Server_HandlePVF.sqf is simpler: it resolves SRVFNC<Command> and spawns it with no destination filtering.

Wrapper To Engine Primitive Map

Wrapper	Direction	Engine primitive	Destination handling
Common_SendToServer / optimized variant	client -> server	publicVariable or publicVariableServer	Server PVF receives command payload.
Common_SendToClients	server -> clients	publicVariable	Payload element 0 is nil, side, or UID.
Common_SendToClient	server -> one client	publicVariableClient to owner _player	Player object is rewritten to UID for the client filter.

Second-Level Multiplexers

Some registered commands are broad routers:

• Client/PVFunctions/HandleSpecial.sqf switches over tags such as join-answer, attack-wave, commander-vote and endgame.
• Client/PVFunctions/LocalizeMessage.sqf switches over message keys such as Teamkill, FundsTransfer and AttackModeActivated.

When tracing one feature, grep the string tag as well as the PVF command name.

Gotchas

• UID-targeted SendToClients still broadcasts to every client and lets non-matching clients discard locally. Use SendToClient for true unicast when possible.
• PVF handlers use Spawn, so rapid messages that mutate shared state have no strict ordering guarantee.
• Both dispatchers use Call Compile on the generated function-name string per dispatch. DR-38 notes this is redundant as well as unsafe: Init_PublicVariables.sqf already precompiles SRVFNC* / CLTFNC* globals at init, so a validated missionNamespace getVariable lookup removes per-message recompilation and closes the DR-1 RCE with the same change.
• Some bare PV channels are copied per side, such as wfbe_supply_temp_west and wfbe_supply_temp_east; there is no resistance-side handler in that path.
• A real BattlEye PV filter must include direct non-PVF channels as well as WFBE_PVF_*; the current repo filter only contains kickAFK.
• The master/Chernarus branch documented here does not ship PR #1 supply-helicopter source; it has the older truck supply mission path plus direct support/supply/ICBM channels. Treat supply-heli mechanics as PR-only until the branch is merged.

Security: the Call Compile trust boundary

Server_HandlePVF.sqf / Client_HandlePVF.sqf run Call Compile on the function-name string taken from the value a remote machine broadcast (select 0 / select 1), with no check that it names a registered command — and the shipped BattlEyeFilter/publicvariable.txt only carries the kickAFK feature rule, not a security filter. Validate the command string against the known SRVFNC*/CLTFNC* set before compiling, and add a real BattlEye PV filter (restrictive default + whitelist of WFBE_PVF_* and the direct channels, keeping kickAFK). Full analysis and remediation playbook: Deep-review findings DR-1.

Residual Authority Risks After Dispatch Hardening

Replacing Call Compile with mission-namespace lookup closes arbitrary code execution from forged function-name strings, but it does not make registered commands authoritative. Hilbert's PV boundary pass found several handlers that still need per-handler sender and payload validation:

Handler	Trust issue	Evidence
RequestChangeScore	Client payload can overwrite score and broadcast the result.	Server/PVFunctions/RequestChangeScore.sqf:3-13
RequestStructure / RequestDefense	Server side mostly checks class existence, then trusts side, position, direction and manning.	Server/PVFunctions/RequestStructure.sqf:3-21, RequestDefense.sqf:2-10
RequestUpgrade	Directly spawns upgrade processing; handler itself does not show commander/funds validation.	Server/PVFunctions/RequestUpgrade.sqf:5, Server/Functions/Server_ProcessUpgrade.sqf:40-43
RequestVehicleLock	Locks the payload vehicle without visible owner/side/range check.	Server/PVFunctions/RequestVehicleLock.sqf:3-8
RequestTeamUpdate	Accepts array or side and mutates group behavior/combat/formation/speed.	Server/PVFunctions/RequestTeamUpdate.sqf:3-26
RequestSpecial	Broad router for paratroops, support, ICBM, camp repair, teamleader update and HC registration. Claude DR-27 found the "ICBM" branch can be forged to server-spawn NukeDammage at a client-chosen position with no upgrade/commander/funds validation.	Client/Module/Nuke/nukeincoming.sqf:23, Server/PVFunctions/RequestSpecial.sqf:1, Server/Functions/Server_HandleSpecial.sqf:97-112

Highest-Priority Registered Command: ICBM / Nuke

DR-27 makes RequestSpecial the highest-priority registered-command hardening target discovered so far. The Tactical menu does client-side ICBM gating and the client sends ["RequestSpecial", ["ICBM", side, baseObj, cruiseObj, team]]; the server's HandleSpecial "ICBM" case trusts the payload and spawns nuke damage from it. A forged PV therefore becomes a server-applied map-wide kill. Fixes belong server-side in the "ICBM" branch, paired with BattlEye restrictions around RequestSpecial.

Direct Channel Authority: Attack Waves

McClintock's 2026-06-02 PV scout found one direct-channel authority issue outside the generic PVF dispatcher, and Claude DR-41 source-verified it as high risk:

• Client/FSM/updateclient.sqf:240 gates the action with a client-side GetSideSupply >= 25000 condition.
• Common/Functions/Common_AttackWaveActivate.sqf:3-8 sends ATTACK_WAVE_INIT = [_supply, _side] via publicVariableServer.
• Server/Functions/Server_AttackWave.sqf:5-15 takes both values directly from the payload and computes ATTACK_WAVE_PRICE_MODIFIER.
• WFBE_C_ECONOMY_SUPPLY_MAX_TEAM_LIMIT = 50000 at Common/Init/Init_CommonConstants.sqf:166, so a forged _supply >= 70000 can drive the side-wide unit price modifier to zero; larger values can make it negative.
• The repo's BattlEyeFilter/publicvariable.txt does not cover ATTACK_WAVE_INIT.

A PVF lookup hardening patch does not touch this path. The forgery class has two surfaces: registered PVF commands and direct publicVariableServer channels. The attack-wave fix should treat ATTACK_WAVE_INIT as a request, re-derive real side supply and permissions server-side, deduct any intended cost server-side, clamp the resulting modifier and ignore client-supplied economic fields. Implementation detail is captured in Attack-wave authority playbook.

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