Files
BT411/context/steam-networking.md
T
CydandClaude Fable 5 75f136e9ff KB: step-4 closeout -- Steam wire documented, live-test procedure, router
docs/GLASS_COCKPIT.md gains the step-4 ledger (seam/transport/lobby + THE
FAKEIP LESSON); NEW context/steam-networking.md topic (+ router row) and
docs/STEAM_TEST.md (the 2-machine live procedure = the step-4 exit criterion
on user hardware).  context/glass-cockpit.md: steps 3+4 status.  Final purity
re-check: pod build clean, forced-walk mission runs, ZERO glass/steam tags in
the pod log.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-18 00:05:51 -05:00

47 lines
2.8 KiB
Markdown

---
id: steam-networking
title: "Steam networking — the BT_STEAM wire (transport + lobby)"
status: living
source_sections: "docs/GLASS_COCKPIT.md §4; docs/STEAM_TEST.md; commits e79e8fa/48ede2f/f703bb1"
related_topics: [glass-cockpit, multiplayer]
key_terms: [PadRIO, miniconsole]
open_questions: ["live 2-account cross-machine session (docs/STEAM_TEST.md) — the step-4 exit criterion"]
---
# Steam networking — the BT_STEAM wire
Internet MP for the glass cockpit (dev tooling; gate `BT_STEAM`, requires `BT_GLASS`).
**Status: CODE COMPLETE 2026-07-18; single-machine verified; live 2-machine test pending.**
## The three layers
1. **The wire seam** (`L4NET.CPP`, always compiled): file-local `BTNetSend/Recv/Accept/Close`
wrappers around the 9 raw Winsock sites — pure code motion when OFF; under `BT_STEAM` each
offers the op to the transport first. Est. delegates: `CheckSocket` (peer address),
`OpenConnection` TCP_OPEN head, `GetMyAddress` (self token).
2. **The transport** (`engine/MUNGA_L4/L4STEAMNET.*`, gated): `ISteamNetworkingSockets`
pseudo-SOCKETs (`0x5EA0xxxx`); engine TCP byte stream over reliable-NoNagle messages with
per-connection reassembly rings (recv: empty→`WSAEWOULDBLOCK`, closed→0); listen channels
console=0 / game=1 (`CreateListenSocketP2P`); install on env `BT_STEAM_NET=1`; degrades to
Winsock at every failure. Pump = `SteamAPI_RunCallbacks` AND sockets `RunCallbacks` (the
general dispatch carries the async results — sockets-only pumping stalls).
3. **The lobby** (`game/glass/btl4lobby.*`, gated): ISteamMatchmaking room (`btl4=1` list
filter); pilots publish name/mech/color; the host's GO mints the roster and signals.
## THE TOKEN MODEL (the FakeIP lesson) [T2]
FakeIP does NOT survive the per-mission process relaunch (live-disproven prior-art assumption:
menu and mission processes got different FakeIPs; the pod timed out dialing its own stale
address). Roster addresses are therefore **opaque ipv4-shaped tokens**`169.254.77.N`, port
1501=console / 1502=game — minted by the HOST at GO and mapped to **Steam identities**;
connections ride `ConnectP2P(identity, channel)`. Handoff to mission processes via env:
`BT_FE_MYFAKE` (own token → `GetMyAddress` self-match) + `BT_FE_STEAMMAP`
(`ip=steamid64;...`). The engine's roster matching, Waterloo swap logic, and self-identification
all run UNCHANGED on tokens.
## Testing
Single-machine (verified): lobby-of-1 GO → token map → egg roster token → mission runs over the
stock console ladder. Live 2-machine procedure + checklist: `docs/STEAM_TEST.md`. AppID 480
(Spacewar) via auto-written gitignored `content/steam_appid.txt`.
## Key Relationships
- Rides: [[glass-cockpit]] miniconsole (marshal has a Steam-wire branch) · Extends:
[[multiplayer]] (the arcade mesh, unchanged above the seam)