chore(network): Remove legacy Send Delay

[githubawn]

What this code did:

The SendDelay setting (m_firewallSendDelay) enabled a specialized NAT traversal mode (FIREWALL_TYPE_NETGEAR_BUG) in FirewallHelper.cpp and NAT.cpp:

1. During pre-game connection setup, it inserted artificial delays (m_timeTillNextSend = -1) on outbound UDP STUN/probe packets sent to peer players.
2. In NAT::establishConnectionPaths(), it rearranged player connection slots into special pairs for nodes identified as having the Netgear NAT bug.
3. In NAT::probed() and NAT::gotMangledPort(), it blocked local clients from sending reciprocal NAT probes until the remote peer probed them first.
4. Exposed a "Send Delay" checkbox in the in-game Options Menu GUI and saved/loaded SendDelay = yes/no in Options.ini.

Background & Reason for Removal:

• Historical Workaround: Added in 2003 specifically for early consumer routers (e.g., Netgear WGR614 v1/v2, WGT624) that violated UDP Binding Stability and Endpoint-Independent Mapping per RFC 4787 (their stateful NAT tables prematurely flushed active socket bindings if rapid UDP packets were sent to multiple STUN mangler destinations).
• Hardware Extinction: Global IPv4 Shodan/Censys scans confirm these 20-year-old 802.11b/g routers are extinct.
• Community Confusion: Over the last 20 years, players frequently confused "Send Delay" in the Options GUI with in-game input lag or network ping delays, leading to endless forum troubleshooting guides instructing users to manually set SendDelay = no in Options.ini. In reality, it had zero effect on in-game performance.
• Code Cleanliness: Removing this eliminates non-standard probe delays in NAT.cpp, removes dead code across FirewallHelper, OptionPreferences, and GlobalData, and hides the obsolete setting from the Options GUI.

[greptile-apps]

Greptile Summary

This PR removes the legacy SendDelay / Netgear-bug NAT workaround that was introduced in 2003 for early consumer routers that reset UDP bindings on rapid STUN traffic. With those devices extinct, the code was dead and confused players for decades.

• Core networking (FirewallHelper.cpp, NAT.cpp): All FIREWALL_TYPE_NETGEAR_BUG detection, the special Netgear-pair ordering in establishConnectionPaths(), and the conditional probe-delay logic in probed() / gotMangledPort() are removed; the simplified path now always sends the probe immediately upon receiving the mangled port.
• Data model (GlobalData, OptionPreferences): m_firewallSendDelay field and getSendDelay() are deleted from both the Generals and GeneralsMD code trees; FIREWALL_TYPE_NETGEAR_BUG = 8 is renamed FIREWALL_TYPE_UNUSED = 8 to preserve the bitmask slot.
• GUI (OptionsMenu.cpp, both trees): Static checkSendDelay variables and all save/load/set-defaults calls are removed; the obsolete checkbox is hidden at runtime via #if ENABLE_GUI_HACKS without modifying the .wnd file yet.

Confidence Score: 5/5

Safe to merge — this is a clean removal of a 20-year-old workaround with no surviving callers or side-effects.

Every call site for m_firewallSendDelay, getSendDelay(), and FIREWALL_TYPE_NETGEAR_BUG is consistently removed across both the Generals and GeneralsMD trees. The m_beenProbed field, which might appear orphaned, is still read in connectionUpdate() to stop retrying mangled-port sends after the remote has probed us — so no dead state remains. The gotMangledPort() simplification (always send probe immediately) is the correct unconditional behavior now that the Netgear delay path is gone. The GUI hide-via-winHide approach under ENABLE_GUI_HACKS matches the established pattern in the codebase.

Files Needing Attention: No files require special attention.

Important Files Changed

Filename	Overview
Core/GameEngine/Source/GameNetwork/NAT.cpp	Removes Netgear-pair ordering in establishConnectionPaths(), probe delay in doThisConnectionRound(), and conditional probe suppression in probed()/gotMangledPort(); m_beenProbed is still read in connectionUpdate() to stop retrying mangled-port sends, so it remains live.
Core/GameEngine/Source/GameNetwork/FirewallHelper.cpp	Strips FIREWALL_TYPE_NETGEAR_BUG set-up from detectionBeginUpdate(), removes hardness/retries contributions, and cleans up dead #if(0) block; all remaining logic is unaffected.
Core/GameEngine/Include/GameNetwork/FirewallHelper.h	Renames FIREWALL_TYPE_NETGEAR_BUG to FIREWALL_TYPE_UNUSED (preserving value 8 to avoid future bitmask collisions) and removes both isNetgear() overloads.
Generals/Code/GameEngine/Source/GameClient/GUI/GUICallbacks/Menus/OptionsMenu.cpp	Removes checkSendDelay static variable and all save/load/set-defaults calls; hides the checkbox at runtime via #if ENABLE_GUI_HACKS (always defined to 1) without touching the .wnd file yet.
GeneralsMD/Code/GameEngine/Source/GameClient/GUI/GUICallbacks/Menus/OptionsMenu.cpp	Mirrors the Generals OptionsMenu changes: removes checkSendDelay state and save/load; hides checkbox via #if ENABLE_GUI_HACKS.
Generals/Code/GameEngine/Include/Common/GlobalData.h	Drops m_firewallSendDelay field; no other member changes.
GeneralsMD/Code/GameEngine/Include/Common/GlobalData.h	Mirrors Generals GlobalData.h: drops m_firewallSendDelay field.
Core/GameEngine/Source/Common/OptionPreferences.cpp	Removes getSendDelay() implementation; remaining preference accessors unchanged.
Core/GameEngine/Include/GameNetwork/NAT.h	Removes already-commented-out NATCONNECTIONSTATE_NETGEARDELAY enum value; no other changes.

Sequence Diagram

sequenceDiagram
    participant Local as Local NAT
    participant Mangler as STUN Mangler
    participant Remote as Remote NAT

    Note over Local,Remote: Simplified flow after SendDelay removal

    Local->>Mangler: Probe (STUN request)
    Mangler-->>Local: Mangled port response
    Local->>Remote: gotMangledPort → sendAProbe (immediately, no delay)
    Local->>Remote: notifyTargetOfProbe
    Note over Local: state = WAITINGFORRESPONSE

    Remote->>Local: Probe packet
    Local->>Remote: "probed() → m_beenProbed=TRUE"
    Note over Local: connectionUpdate() stops retrying mangled port sends

    Remote-->>Local: Connection response
    Note over Local,Remote: Connection established (DONE)

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_{Reviews (4): Last reviewed commit: "review feedback" | Re-trigger Greptile}

[bobtista]

Left one question, otherwise this looks good

[bobtista]

Looks good to me

[xezon]

How confident are we that no player never ever needs this delay thing?

[githubawn]

Highly confident.
All the Send Delay discussion I could find online is anecdotal, always bundled with other fixes or tools, never isolated as the actual cause.
That said, it's part of why I split the networking refactor into separate PRs (3 so far, 4 more planned), each one is independently revertible if something like this turns out to matter for someone.

[xezon]

Ok. I am not opposed to removing it.