Campaign N slice N4 completes the AckNakScheduler NAK branch and closes
the ACE cleartext-reject keystream hazard - the slice that makes S2C
loss actually RECOVER.
NAK emission (SharedNet::EnqueueNaks @ 0x00543BD0):
- One cleartext exact-flags RequestRetransmit per sweep behind the
STRICT 0.6 s gate on the ONE shared timestamp (the x87 0x41-mask test
at 0x00543C03 proceeds only on strictly-greater; the ack's gate stays
>=). Never an ack in a NAK sweep; a NAK delays the next ack by 2.0 s
and vice versa (landmine #7).
- Body = u32 count + ids ascending, capped at 114 (ReceiverData::GetNaks
@ 0x005490C0, cap 0x72; the m_cbData = 4*count+4 store at 0x00543C3E);
header Sequence borrowed from highestIDSent_ without incrementing;
cleartext or ACE ignores it (landmine #6, NetworkSession.cs:283-284) -
and a NAK never refreshes ACE's 60 s timeout.
- Control-header rule decided once for BOTH ack and NAK: Time = the
interval id, Iteration = the session iteration, matching retail's
shared header build (FlowQueue::TransmitNewPackets @ 0x00547A60, the
stack build at 0x00547A84). ACE reads neither field inbound.
- Gate ticks now round instead of truncate: 0.6 has no exact double
form, and truncation opened the strict gate exactly AT the boundary.
RejectRetransmit reclaim (divergence register AD-51, ACE adaptation):
- ACE's RejectRetransmit consumes a FRESH sequence, cleartext, with NO
keystream word, and is cached (ACE NetworkSession.cs:299-304,
:722-725, :743-748) - the one place ACE breaks retail's gap-walk
invariant that every missing id was word-bearing (retail cleartext
always borrows live sequences). Unhandled, the gap walk parks a word
for the reject's id and the inbound stream runs permanently one word
ahead - the N2 desync class reintroduced through the reject path.
- Fix: on a VALIDATED cleartext reject, InboundSequenceTracker removes
the mis-park, shifts every later-drawn parked word down one position
(per-word draw ordinals; ascending wrap-safe id <=> ascending draw
order), and pools the excess word, consumed lowest-draw-order-first
ahead of fresh ISAAC draws. Exact for any number of interleaved
rejects in ANY arrival order - a plain reclaim FIFO is not: a reject
arriving after a higher encrypted arrival crosses the parked chain,
and two out-of-order rejects pool their excess words out of draw
order (both orderings pinned by tests).
- Reject BODY ids keep N2's discard: word-bearing server-side,
consumed-in-place. The pool is provably empty against retail servers.
N3 advisories folded (all five): honest transitional-state wording (the
empty N3 NAK branch could silently disconnect a loopback session at
ACE's 60 s timeout, witness [net-tick] acks/s=0), the
ReceiverData::SharedInit @ 0x00548EF0 (from Init @ 0x00548FA0)
citation, the FlowQueue::Empty pump-order wording (TransmitNaks ->
TransmitAcks -> TransmitNewPackets with the interval increment LAST @
0x00548A9D; our clock-first Sweep is cosmetic vs ACE), the
Time/Iteration rule above, and the stale WorldSession budget-break
comment rewritten to the sweep reality.
Tests: 737 Core.Net green (14 new in NakEmissionTests + updated N3
pins): strict-gate boundary, shared timestamp both directions,
NAK-xor-ack exclusivity, full wire-shape + 114-cap pins, model-served
retransmission round trip, five tracker reclaim proofs, the 130 s
virtual prune -> fresh-sequence reject system test (victim abandoned,
later traffic decodes, pool drains to zero), 10 s long-loss survival
(NAKs on the gate cadence, zero acks, heal inside the window), and the
capstone soak: 2% seeded bidirectional loss x 10,000 messages -> zero
message loss both ways, ACE crypto headroom 256 at convergence, every
ledger drained (cache at the single watermark entry - retail's Flush
prunes STRICTLY below the ack). Full solution Release: 9,758 passed /
5 skipped. Connected world-lifecycle gate PASS
(logs/connected-world-gate-20260729-150238); canonical nine-stop soak
PASS (logs/connected-r6-soak-20260729-150856).
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>
Erik