Campaign N Slice N5 (docs/plans/2026-07-29-network-transport-campaign.md
section 8 rung 3): the permanent removal of the loopback blindness that let
#260 ship. Local ACE never drops a datagram, so every historical connected
gate was structurally incapable of exercising the N1-N4 recovery machinery;
from this slice on, tools/run-connected-loss-gate.ps1 runs the standard
lifecycle route through deterministic seeded loss and passes only on proven
non-zero recovery.
Observability:
- [net-tick] gains resend/s nak-out/s nak-in/s rej-in/s dup-drop/s parked/s
reclaim/s cache= nakset= - TransportStats window deltas mirroring the
acks/s cumulative-delta pattern, plus the two instantaneous depths (the
unbounded-like-retail sent-packet cache watchdog and the inbound NAK set).
TransportStats gains RejectsReceived (inbound RejectRetransmit packets).
Counters increment unconditionally; every string is behind
NetDiagnostics.ProbeNet (Code Structure Rule 5).
- WorldSession.Dispose emits one cumulative [net-final] totals line so the
loss gate asserts exact counters instead of reconstructing them from
rounded per-second rates.
- LinkStatusSnapshot.PacketLossPercentage is deliberately NOT wired: filed
#261 - retail's CLinkStatusAverages formula
(LinkStatusHolder::GetPacketLossPercentage @ 0x00411370) must be located
first; inventing a ratio is forbidden.
N4-review F3 fold-in:
- Fresh reliable sends stamp Header.Iteration = the session iteration
through the same shared retail header build already cited for Time (N3)
and the N4 control packets: FlowQueue::TransmitNewPackets @ 0x00547A60,
the stack build at 0x00547A84/0x00547AA8. The control-header rule now
holds across all three send shapes (fresh reliable, ack, NAK). ACE reads
neither Time nor Iteration inbound (campaign section 3) - wire-safe, and
resends keep the stamp verbatim per the N1 rebuild rule.
Loss injection (Transport/LossyTransportDecorator):
- IWorldSessionTransport wrapper with deterministic seeded per-direction
loss. Config via NetDiagnostics typed env properties read once:
ACDREAM_NET_DROP_PCT (0 = off = default), ACDREAM_NET_DROP_SEED (default
1), ACDREAM_NET_DROP_DIR (out|in|both, default both).
- Arming gate: NOTHING drops in either direction until the decorator has
FORWARDED the first ENCRYPTED outbound datagram - parse-free check on
length > 20 with EncryptedChecksum set in the LE flags word at bytes
4..8. The cleartext handshake always survives and the arming datagram is
never a casualty; handshake-loss testing belongs to N6's ConnectResponse
0.333 s retransmit.
- Structurally absent at 0%: WrapIfConfigured returns the raw transport -
WorldSession's default factory is the only production seam and a normal
run never constructs the decorator.
Root-cause fix the gate immediately exposed:
- The logoff-confirmation wait in Dispose processed inbound datagrams but
never pumped the transport, so a lost S2C logoff confirmation was
gap-detected but its healing NAK never went out. Retail's pump
(Client::UseTime @ 0x00411C40 -> PacketController::UseTime @ 0x005410D0)
runs until LogOffServer; the wait now sweeps per processed datagram,
making the logoff wait the third covered blocking pump (after Tick and
the handshake loops). A lost C2S logoff REQUEST remains unrecoverable by
ACE design (arrival-driven NAK; a quiet client is never NAKed - campaign
section 3 row 1), recorded in the gate header.
Gates:
- tools/run-connected-loss-gate.ps1 (-DropPct 2 -Seed 1): PASS vs local
ACE - the first automated observation of packet loss in project history.
Decorator ledger: dropped out=3 in=10 of forwarded out=183 in=496.
[net-final] resends=2 nak-in=2 nak-out=6 rej-in=0 acks-out=114
acks-in=119 dup-drop=0 sanity-drop=0 cksum-fail=0 parked=9 reclaimed=0
uncached-nak=0 cache=1 nakset=0. Every injected loss healed: both
ACE-driven C2S resend recovery (nak-in=2 -> resends=2) and client-driven
S2C NAK recovery (parked=9 -> nak-out=6) fired on a real connected
route, all six checkpoints validated, graceful logout confirmed, ACE
recorded the transport Disconnect.
- tools/run-connected-world-lifecycle-gate.ps1 (decorator absent): PASS -
zero behavior change on the no-loss baseline; the gate now defensively
clears the drop env vars.
- Core.Net Release: 747/747 (737 + 10 N5: decorator determinism/direction/
arming/structural-absence/env parsing, the 5% seeded WorldSession lossy
lifecycle with zero message loss both ways + ACE Headroom 256, the
[net-tick] field pins, the Iteration stamps).
- Full solution Release: 9,763 passed / 5 skipped / 0 failed.
Test-fixture note: FakeAceTransport gains AutoAdvanceOnBlockingReceive so
virtual time can move during the blocking Connect()/EnterWorld() pumps -
with the clock frozen there, a dropped handshake-window datagram could
never be NAK-healed (a fixture artifact, not a transport property).
Campaign section 9 ledger row added (SHA recorded at N6 kickoff).
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Campaign N Slice N2 (docs/plans/2026-07-29-network-transport-campaign.md
S2.2) - the second fatal #260 fix: the inbound keystream now aligns to
SEQUENCE order instead of arrival order. One lost S2C datagram no longer
desyncs the inbound cipher permanently - the missing id's pre-drawn key
parks in the NAK set, later packets keep decoding, and the retransmission
decodes with the parked key.
New src/AcDream.Core.Net/Transport/InboundSequenceTracker.cs - retail's
ReceiverData inbound half, ported rule for rule:
- Sanity window: drop when seq is wrap-safe newer than
highestIDReceived_ + 0x7FFF (SharedNet::SeqIDSanityCheck @ 0x00543A20;
the boundary itself is accepted).
- Duplicate/late arrival (encrypted, at/below the watermark): NAK-set
hit -> decrypt with the PARKED pre-drawn key; miss -> silent drop at
ZERO keystream cost (SharedNet::ProcessNewSeqNum @ 0x00544690, the
AVL::Remove branch) - the dup-word-burn and double-dispatch bugs close
together.
- Gap walk (SharedNet::ProcessNewestSeqNum @ 0x00541930): one inbound
ISAAC word per missing id, drawn IN SEQUENCE ORDER BEFORE the arriving
packet's own key (landmine #4), parked beside the id
(ReceiverData::AddNakked @ 0x00549240, idempotent; id 0 skipped per
retail's `if (esi_1 != 0)`). Cleartext walks to seq+1 - the borrowed
id itself gets NAKed, so the real encrypted packet at that id can
still decode later.
- Verify-failure re-park: a sequenced encrypted checksum failure parks
the consumed key back beside its id so the retransmission decodes
(SharedNet::ProcessPacket @ 0x00544790 tail, AddNakked(seq, &key)).
- Inbound RejectRetransmit -> silent NAK-set abandonment; parked keys
discarded, alignment holds because the words were already drawn
(SharedNet::HandleEmptyAck @ 0x005448F0).
- NAK set = SortedDictionary<uint,uint> seq -> parked key; ascending
raw-uint enumeration matches retail's AVL walk for N4's <=114-id NAK
emission (ReceiverData::GetNaks @ 0x005490C0).
PacketCodec split (campaign S4, retail's own factoring - the key is an
optional in/out of ReceiverData::Decrypt): TryParseBorrowed is the pure
parse + checksum-summand computation with NO keystream access anywhere;
VerifyChecksum(header, headerHash, payloadHash, uint? key) compares the
additive cleartext form (null) or headerHash + (key ^ payloadHash).
TryDecodeBorrowed(datagram, IsaacRandom?) - the consume-before-compare
site that WAS the bug - is deleted; the owned TryDecode stays
(test-only). RejectRetransmit ids are now exposed on both decoders
(borrowed RejectRetransmitBytes/Count like the Request pair; owned
RejectRetransmits list); the bytes were always inside the hashed span,
so parse-hash coverage is unchanged.
WorldSession: ProcessDatagram head is now parse -> sequence-0 split
(cleartext seq-0 = handshake/control, verified additively and processed
as before; encrypted seq-0 dropped before any keystream access, like
retail's ProcessPacket) -> tracker.Admit -> VerifyChecksum with the
admission key -> failure re-park -> unchanged flag handling, N1
transport consumption, reflex ack, and fragment loop. The
RejectRetransmit flag routes to the tracker beside the N1 NAK/ack
consumption. The handshake Connect loop moved to parse +
cleartext-verify (no tracker exists before ISAAC seeding; the
ConnectRequest is cleartext seq 0). ReliableTransport now takes both
Isaacs and exposes Inbound; the session's _inboundIsaac field is
deleted. No production caller constructed the N1 ctor outside
WorldSession, so no compatibility shape was kept.
TransportStats gains InboundDupsDropped, InboundSanityDrops,
ChecksumFailures, KeysParked (unconditional, like the N1 counters).
Watermark init = 1 is an ACE adaptation, register row AD-50 (watermark
INIT only, not a mechanism change; AD-49 stays reserved for the campaign
S5 blob-layer deferral): retail zero-inits ReceiverData, but ACE never
emits S2C sequence 1 - PacketSequence starts unprimed at uint.MaxValue,
the cleartext ConnectRequest takes NextValue 0, and the first ENCRYPTED
flush re-primes CurrentValue to 1 so the first encrypted sequenced
packet is 2 (ACE NetworkSession.cs:716-717 resolving to
UIntSequence(startingValue: 1), Sequence/UIntSequence.cs:9-13,30-41).
A zero-init watermark would gap-walk the permanent id-1 hole: one
spurious NAK, the first pre-drawn word mis-assigned to id 1, and the
keystream off by one from the first encrypted packet onward. holtburger
seeds the same value (crates/holtburger-session/src/session/api.rs:30,
last_server_seq: 1), mirroring ACE's own C2S-side
lastReceivedPacketSequence = 1 (NetworkSession.cs:57). The N0 model's
dance is pinned by the clean-lifecycle conformance test: min encrypted
S2C sequence == 2, zero NAKs, zero spurious drops.
Tests (+14; Core.Net 702 -> 716): the decisive gap test (10,11,13,14 -
13 and 14 decode with fresh words while 12's key parks with
KeysParked=1/NakCount=1, the late 12 decodes with the parked key, 15
takes the next fresh word - impossible pre-N2), zero-cost duplicate
drop (shadow ISAAC position unchanged), re-park -> byte-identical
retransmission decode, the cleartext borrowed-id rule, cleartext at the
watermark (no NAK/key/watermark change), sanity boundary +0x7FFF
accepted / +0x8000 dropped wrap-safe, skip-id-0 across the 32-bit wrap
with ascending NAK enumeration, RejectRetransmit abandonment with
alignment held, warm zero-alloc Admit; plus four real-WorldSession
conformance runs against the N0 ACE double: clean lifecycle (zero NAKs
at every stage), S2C loss of one packet of a Count=2 fragment set
(later packets STILL decode - the N2 win; late byte-identical
redelivery completes the split message intact), duplicate delivery
dropped BEFORE dispatch, and the seq-0 tracker bypass.
N3/N4 handoff notes are recorded in the campaign S9 N2 row: the interim
per-packet reflex ack acks the arriving sequence even while a gap is
parked (ACE prunes the lost id from its S2C cache before N4 could NAK
it - message recovery needs N3's retail NAK-xor-ack sweep), and ACE's
RejectRetransmit consumes a fresh CLEARTEXT sequence with no keystream
word, an ACE-vs-retail wrinkle N4's design must resolve.
Gates: dotnet build green; AcDream.Core.Net.Tests 716/716;
full-solution Release 9,732 passed / 5 skipped / 0 failed; connected
world-lifecycle gate vs local ACE RESULT=PASS (zero failures, one
pre-existing expected world-edge landblock-miss warning); canonical
nine-stop connected route RESULT=PASS.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Campaign N slice N0 (docs/plans/2026-07-29-network-transport-campaign.md):
the referee that slices N1-N5 are graded against, test-project only, zero
production changes.
- VirtualClock: Stopwatch-shaped deterministic time source (fixed 100 ns
ticks) that N1 will inject behind the production TransportClock.
- AceCryptoModel: verbatim port of ACE CryptoSystem Search/ConsumeKey over
our IsaacRandom - 256-key window, parked-key set, Headroom/OrphanCount
diagnostics (CryptoSystem.cs:8-49 cited per method).
- AceSessionModel: transport-free ACE NetworkSession over raw datagrams,
every rule cited to NetworkSession.cs - CRC-before-everything silent
drop, cleartext-NAK early return (no timeout refresh, :283-308),
60 s timeout refresh (:329-331), exact-equality ack dedup exemption
(:342-347), desired+2 NAK trigger with 1 s limit (:351-363), >window
AbnormalSequenceReceived (:393-397), the :474-476 watermark hole,
ack-value cache prune (:663-673), fragment gate (:532-543), seq>=2
caching (:730), Retransmission-flag resends with the ORIGINAL IssacXor
(:675-686), RejectRetransmit, 2 s cleartext cumulative ack, 20 s
TimeSync, EchoResponse, 120 s cache prune (:251-262). ACE's raw
wrap-unsafe comparisons are modeled bug-for-bug, not fixed.
- LossyLink: deterministic drop/reorder/seeded-loss fault injector, pure
data structure.
- FakeAceTransport: IWorldSessionTransport binding a REAL WorldSession to
the model through the link, with the handshake scripted (ConnectRequest
reusing the negotiation fixture layout, CharacterList, ServerReady,
logoff confirmation) - genuine Connect/EnterWorld/Tick/Dispose with no
sockets.
- 19 new tests pin the double, including
CleartextNonAckAdvancesWatermark_TheAceHole (the self-induced wedge
behind scope rows TS-57/TS-58/AP-125), re-key = permanent orphan,
unrequested-resend window burn, the 115-id NAK cap boundary, and a
full no-socket session lifecycle with both ISAAC streams verified
aligned end-to-end.
Core.Net suite: 678 passed / 0 failed (659 existing + 19 new).
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Erik