Networking WORKS: real console <-> real pod over the emulated wire
The emulated SheepShaver console and DOSBox pod now exchange the live console protocol on TCP 1501. Required chain: rebuild the DOSBox pcap backend + launch with C:\Windows\System32\Npcap on PATH (npcap DLL location); a two-TAP Windows bridge (single shared TAP fails); TAP2 MediaStatus=Always-Connected; and binding the pod's pcap to the BRIDGE MINIPORT (not a member TAP -- member-injected frames aren't re-forwarded), via realnic=DB5521D (letter-leading GUID fragment; leading-digit is parsed as an interface index). Captured + decoded the real protocol values (StateResponse clientID=5/flags=1/host=0/state=1/app=1=BattleTech), which corrects the earlier synthetic guesses. Full writeup in NET-NOTES.md. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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Claude Fable 5
@@ -292,6 +292,54 @@ same TAP/bridge (200.0.0.113 already via WATTCP). Then the console's
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outbound TCP to 200.0.0.113:1501 reaches the pod and we capture the egg
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exchange (resolves the framing + endianness caveats above).
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## MILESTONE: real console <-> real pod talking over the wire (2026-07-05)
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The emulated SheepShaver console and the emulated DOSBox pod now exchange
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the live console protocol on TCP 1501. Hard-won setup (all required):
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1. **DOSBox-X pcap backend had to be rebuilt + npcap DLL path.** config.h
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had `C_PCAP 1` but the stale `ethernet.o` predated it; force-recompile
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(`rm src/misc/ethernet.o ethernet_pcap.o; make`). Runtime: npcap installs
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its DLLs in `C:\Windows\System32\Npcap\` (npcap-only mode), NOT System32,
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so DOSBox couldn't load wpcap.dll -> **launch dosbox-x.exe with
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`C:\Windows\System32\Npcap` prepended to PATH.**
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2. **Two-TAP Windows bridge** (single shared TAP fails: SheepShaver holds the
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user-mode handle, DOSBox rides NDIS, frames don't cross). Console
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SheepShaver -> TAP1 (`ether tap` + etherguid); pod -> TAP2; both bridged.
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3. **TAP2 media status = Always-Connected** (registry MediaStatus=1 on the
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TAP2 class key, needs elevation; the GUI toggle didn't persist). Without
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it TAP2 reports "unplugged" and the bridge won't forward to it.
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4. **Pod pcap binds to the BRIDGE MINIPORT, not a member TAP.** Injecting on
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a bridge *member* (TAP2) isn't re-forwarded by the bridge (the pod TX'd
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but the console never saw it). Bind DOSBox `realnic` to the bridge
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miniport = "Microsoft Network Adapter Multiplexor Driver". GOTCHA: DOSBox
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`realnic` matches a substring of the pcap device NAME (`\Device\NPF_{GUID}`)
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and parses a *leading-digit* value as an interface index -- the bridge
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GUID `5DB5521D...` starts with 5 -> picked iface #5 (Bluetooth!). Use a
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letter-leading fragment: `realnic=DB5521D`.
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5. Diagnostics: added `PCAP TX/RX` counters to `ethernet_pcap.cpp`
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(SendPacket/GetPackets) -- confirmed the pod WAS transmitting all along;
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the bridge forwarding was the only gap. Capture the wire with
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`dumpcap -i <bridge#> -f "arp or tcp port 1501" -w cap.pcapng`.
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**Verified protocol on the wire (little-endian, matches the source decode):**
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- Console->pod **StateQuery** (32B): hdr clientID=4(App) gameID=0 fromHost=1
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ts=.. ; msg len=16 id=3 flags=0 ; body requestingHost=1.
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- Pod->console **StateResponse** (40B): hdr **clientID=5 (ConsoleClientID)**
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gameID=0 fromHost=0 ts=.. ; msg len=24 id=1 **flags=1 (Reliable)** ; body
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respondingHostID=0, **applicationState=1**, application=1 (BTL4/BattleTech).
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(My earlier synthetic guess had clientID=4/flags=0/host=1/state=0 -- all
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wrong, which is why the real console rejected the stand-in. These are the
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correct values for pod_responder.py.)
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- Console polls StateQuery ~every 2s; pod ACKs + StateResponse each time.
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Clean 3-way handshake; zero-length "dup ACKs" are benign keepalives.
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OPEN: with this working, the console still hadn't enabled mission-send in
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the stripped-down (keyboard-only, no-RIO, no-sound) pod boot -- retrying
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with a full RIO+sound boot (`net_full.conf`) so the pod presents its normal
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state (applicationState may change when fully booted). Need the console UI
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readout to know what state it wants before it will send the mission egg.
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## Open questions / notes
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- Exact TCP listen port(s) — not in the source grep; get from NETNUB.EXE
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or a capture at milestone 3.
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@@ -0,0 +1,129 @@
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#!/usr/bin/env python3
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"""Minimal stand-in POD: answer the 4.10 console's StateQuery so it unlocks
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mission-send, then capture the mission-egg delivery.
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Protocol (decoded from CODE/RP/MUNGA/{APPMSG,CONSOLE,NETWORK}.HPP):
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- Console TCP-connects to the pod (port 1501) and repeatedly sends an
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Application StateQueryMessage (clientID=4 App, wire messageID=3) until
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the pod answers, THEN it lets the operator send a mission.
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- The pod answers with a ConsoleApplicationStateResponseMessage
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(messageID=1, size 24: respondingHostID, applicationState, application).
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application = BTL4 = 1 (Puck runs BattleTech).
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- Wire is LITTLE-ENDIAN (Mac console byte-swaps via LEDWORD; confirmed by
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capture). Every packet = NetworkPacketHeader(16) + Receiver::Message.
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A few values (the "ready" applicationState code, host-ID routing, clientID)
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are inferred; tweak the TUNE block and re-run if the console doesn't accept
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the response. Once it does, send a mission from the console and this logs +
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reassembles the ReceiveEggFileMessage chunks (the egg).
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Usage: python pod_responder.py [port]
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"""
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import socket, struct, sys, time
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PORT = int(sys.argv[1]) if len(sys.argv) > 1 else 1501
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# ---- TUNE: values inferred from headers; adjust if the console rejects ----
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RESP_CLIENT_ID = 4 # ClientID in the response header (query used 4=App)
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RESP_FROM_HOST = 1 # header.fromHost of our response
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RESP_HOST_ID = 1 # respondingHostID (echo the query's requestingHost)
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APP_STATE = 0 # applicationState: 0 = idle/ready (best guess)
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APP_ID = 1 # ApplicationID: RPL4=0, BTL4=1, BTW4=2 -> Puck=BT
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STATE_RESP_MSGID = 1 # ConsoleApplicationStateResponseMessageID
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# ---------------------------------------------------------------------------
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RAW = f"pod_responder_{int(time.time())}.bin"
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def le(*vals):
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return b"".join(struct.pack("<i", v) for v in vals)
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def packet(client_id, game_id, from_host, ts, msg_id, msg_flags, body=b""):
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"""NetworkPacketHeader(16) + Receiver::Message(12 + body)."""
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hdr = le(client_id, game_id, from_host, ts)
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msg_len = 12 + len(body)
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msg = struct.pack("<Iii", msg_len, msg_id, msg_flags) + body
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return hdr + msg
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def state_response():
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body = le(RESP_HOST_ID, APP_STATE, APP_ID) # 12 bytes
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return packet(RESP_CLIENT_ID, 0, RESP_FROM_HOST,
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int(time.time()) & 0x7fffffff,
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STATE_RESP_MSGID, 0, body) # -> 40-byte packet
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def parse_hdr(buf):
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if len(buf) < 28:
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return None
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cid, gid, fh, ts = struct.unpack("<iiii", buf[0:16])
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mlen, mid, mfl = struct.unpack("<Iii", buf[16:28])
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return dict(clientID=cid, gameID=gid, fromHost=fh, ts=ts,
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msgLen=mlen, msgID=mid, msgFlags=mfl)
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def hexdump(b, n=64):
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out = []
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for i in range(0, min(len(b), n), 16):
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c = b[i:i+16]
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out.append(f" {i:04X} " +
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" ".join(f"{x:02X}" for x in c).ljust(48) + " " +
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"".join(chr(x) if 32 <= x < 127 else "." for x in c))
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if len(b) > n:
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out.append(f" ... (+{len(b)-n})")
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return "\n".join(out)
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def main():
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srv = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
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srv.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
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srv.bind(("0.0.0.0", PORT)); srv.listen(1)
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print(f"pod_responder: listening on 0.0.0.0:{PORT} (raw -> {RAW})")
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print(f" reply = StateResponse(host={RESP_HOST_ID}, state={APP_STATE}, "
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f"app={APP_ID}) clientID={RESP_CLIENT_ID}")
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raw = open(RAW, "wb")
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egg = bytearray() # reassembled egg
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egg_total = None
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while True:
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conn, addr = srv.accept()
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print(f"\n=== connection from {addr} ===")
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buf = b""; queries = 0
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conn.settimeout(30)
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try:
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while True:
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chunk = conn.recv(4096)
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if not chunk:
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break
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raw.write(chunk); raw.flush(); buf += chunk
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# frame out concatenated packets: 16B hdr + msgLen body
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while len(buf) >= 28:
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h = parse_hdr(buf)
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total = 16 + h["msgLen"]
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if h["msgLen"] < 12 or h["msgLen"] > 2000:
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print(" ! bad msgLen, dumping:\n" + hexdump(buf))
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buf = b""; break
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if len(buf) < total:
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break # wait for the rest
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pkt, buf = buf[:total], buf[total:]
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print(f"\n<- pkt {total}B {h}")
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print(hexdump(pkt))
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if h["msgID"] == 3: # StateQuery
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queries += 1
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r = state_response()
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conn.sendall(r)
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print(f"-> StateResponse ({len(r)}B) [query #{queries}]")
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elif h["msgLen"] == 1024: # ReceiveEggFileMessage
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seq, flen, tlen = struct.unpack("<iii", pkt[28:40])
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data = pkt[40:40+tlen]
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egg.extend(data)
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print(f" EGG chunk seq={seq} total={flen} "
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f"this={tlen} (have {len(egg)})")
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globals()['egg_total'] = flen
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if flen and len(egg) >= flen:
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fn = f"received_egg_{int(time.time())}.egg"
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open(fn, "wb").write(egg)
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print(f" *** EGG COMPLETE -> {fn} ({len(egg)}B)")
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else:
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print(f" (msgID={h['msgID']} — not handled)")
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except socket.timeout:
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print("(idle 30s)")
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print("=== closed ===")
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conn.close()
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if __name__ == "__main__":
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main()
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