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Inter-BBS Packet & Node-List Formats (developer reference)

This is the on-disk contract for Immortal Barons' inter-BBS ("interplanetary") play. It is a developer reference, not a player/sysop doc — the door setup guide is docs/door-setup.md.

The clone is an independent reimplementation and does not use BRE's binary packet format. It defines its own JSON packets. The node list reuses BRE's plain-text BRNODES.DAT layout (under the clone's own filename ibnodes.dat).

Transport model (Option A, file-drop)

The game only reads and writes packet files in two directories, set per board in config.json:

  • InboundDir — packets from other boards arrive here.
  • OutboundDir — the game writes packets for other boards here.

Moving files between boards is external to the game (a mailer, a sync tool, scp, a shared mount). RunPlanetary (immortal-barons -planetary, also folded into -maint when IBBS is on) reads and applies inbound packets, launches due group attacks, exports this board's scores, and writes the outbox.

Packet files (*.brp)

Each packet is one JSON file. Filename: <from>-to-<to>-<date>-<n>.brp, where <to> is all for a broadcast. A transport that fans out must copy a broadcast to every other board's inbound.

The JSON is game.Packet:

{
  "FromBoard": "AlphaBBS",
  "ToBoard": "",                 // "" = broadcast to the whole league
  "Date": "2026-07-04",          // ISO; used for observed travel-time display
  "Scores":  [ RemoteScore ],    // score share (feeds IP scores / attack targets)
  "Attacks": [ RemoteAttack ],   // strikes landing on ToBoard
  "Results": [ AttackResult ]    // outcomes returning to the origin
}

Component types:

RemoteScore   { "Empire": "Asgard", "NetWorth": 1281, "Land": 100 }

RemoteAttack  { "ID": 1, "FromBoard": "AlphaBBS", "TargetEmpire": "Victim",
                "Offense": 150000, "Contributors": [ Contribution ] }
                // TargetEmpire "" = whole planet (strongest defender)

Contribution  { "Owner": "andy", "Offense": 100000 }   // for splitting spoils

AttackResult  { "ID": 1, "TargetBoard": "BravoBBS", "TargetEmpire": "Victim",
                "LandTaken": 12, "Won": true }

Processing (World.ApplyPacket): a packet addressed to this board (or a broadcast) is applied — scores import into RemoteBoards; attacks resolve against the named empire (offense vs defense, a capped land bite) and produce an AttackResult returned to the origin; incoming results post to the planetary bulletin. A packet addressed to a different board is left in place for the transport to route onward.

Node list: ibnodes.dat

Plain text, one board per six-line block, blank line between blocks (BRE's BRNODES.DAT layout). Loaded at startup into World.LeagueNodes.

1              node number (1 = League Coordinator)
Avalon         board / planet name
363/277        network address
Orlando        city
FL             state / province
USA            country

Board config: BBS.CFG

Optional, seven lines (store.ParseBoardConfig): sysop name, planet name, node address, inbound-file dir, netmail dir, league number, mailer. The clone's own config.json (BoardID, IBBS, InboundDir, OutboundDir) is the authoritative runtime config; the BBS.CFG parser exists for importing a board's identity from an existing BRE-style setup.

Code map

  • internal/game/ibbs.go — packet types, group attacks, resolution, scores.
  • internal/store/ibbs.go — WriteOutbox, ReadInbound, RunPlanetary.
  • internal/store/league.go — ParseNodeList, ParseBoardConfig.
  • scripts/ibbs-smoke.sh — end-to-end 3-board exchange with the real binary.