fix(mtprotoedge): sync admit nested gzip RPC envelopes

go.mod

@@ -9,7 +9,7 @@ require (
 	github.com/golang-migrate/migrate/v4 v4.19.1
 	github.com/gotd/ige v0.3.0
 	github.com/gotd/log/logzap v0.1.1
-	github.com/iamxvbaba/td v1.1.5
+	github.com/iamxvbaba/td v1.2.0
 	github.com/jackc/pgerrcode v0.0.0-20220416144525-469b46aa5efa
 	github.com/jackc/pgx/v5 v5.9.2
 	github.com/lestrrat-go/jwx/v3 v3.1.1

go.sum

@@ -81,8 +81,8 @@ github.com/hashicorp/errwrap v1.1.0 h1:OxrOeh75EUXMY8TBjag2fzXGZ40LB6IKw45YeGUDY
 github.com/hashicorp/errwrap v1.1.0/go.mod h1:YH+1FKiLXxHSkmPseP+kNlulaMuP3n2brvKWEqk/Jc4=
 github.com/hashicorp/go-multierror v1.1.0 h1:B9UzwGQJehnUY1yNrnwREHc3fGbC2xefo8g4TbElacI=
 github.com/hashicorp/go-multierror v1.1.0/go.mod h1:spPvp8C1qA32ftKqdAHm4hHTbPw+vmowP0z+KUhOZdA=
-github.com/iamxvbaba/td v1.1.5 h1:fy6wWQIMzKKOXBwBRcnDaLFhiHyQazJt9eMOrdhl22E=
+github.com/iamxvbaba/td v1.2.0 h1:3RqZir1Yk2uEkECh8JKhXW8cW+dYIGa/21+Q7FtsHnE=
-github.com/iamxvbaba/td v1.1.5/go.mod h1:INkZJi18XbXtVOrldDnPtmQCJvIXhgDZdbo9MV/NY7M=
+github.com/iamxvbaba/td v1.2.0/go.mod h1:INkZJi18XbXtVOrldDnPtmQCJvIXhgDZdbo9MV/NY7M=
 github.com/jackc/pgerrcode v0.0.0-20220416144525-469b46aa5efa h1:s+4MhCQ6YrzisK6hFJUX53drDT4UsSW3DEhKn0ifuHw=
 github.com/jackc/pgerrcode v0.0.0-20220416144525-469b46aa5efa/go.mod h1:a/s9Lp5W7n/DD0VrVoyJ00FbP2ytTPDVOivvn2bMlds=
 github.com/jackc/pgpassfile v1.0.0 h1:/6Hmqy13Ss2zCq62VdNG8tM1wchn8zjSGOBJ6icpsIM=

internal/mtprotoedge/encrypted.go

@@ -349,6 +349,35 @@ func (e *dispatchBadMsgError) Error() string {
 	return fmt.Sprintf("bad client message %d/%d: code %d", e.msgID, e.seqNo, e.code)
 }
 
+var errGZIPExpansionLimit = errors.New("gzip expansion limit exceeded")
+
+type gzipExpansionWorkError struct {
+	expanded int
+	cause    error
+}
+
+func (e *gzipExpansionWorkError) Error() string {
+	if e == nil || e.cause == nil {
+		return "gzip expansion failed"
+	}
+	return e.cause.Error()
+}
+
+func (e *gzipExpansionWorkError) Unwrap() error {
+	if e == nil {
+		return nil
+	}
+	return e.cause
+}
+
+func gzipExpansionWork(err error) int {
+	var work *gzipExpansionWorkError
+	if errors.As(err, &work) && work.expanded > 0 {
+		return work.expanded
+	}
+	return 0
+}
+
 // decodeGZIPWithGlobalBudget reserves the maximum single-wrapper output before
 // decompression starts. Once the actual size is known the excess reservation is
 // returned, while the actual output remains charged until the inbound plan is
@@ -356,6 +385,16 @@ func (e *dispatchBadMsgError) Error() string {
 // This closes the gap where every connection read goroutine could otherwise hold
 // an unaccounted 10 MiB expansion before the shared RPC scheduler saw the body.
 func (s *Server) decodeGZIPWithGlobalBudget(b *bin.Buffer) ([]byte, func(), error) {
+	return s.decodeGZIPWithGlobalBudgetLimit(b, maxSingleGZIPExpandedBytes)
+}
+
+// decodeGZIPWithGlobalBudgetLimit is the caller-bounded form used by exact
+// Layer admission. limit is also capped by the protocol's single-wrapper
+// ceiling; the returned bytes remain charged until release is called.
+func (s *Server) decodeGZIPWithGlobalBudgetLimit(b *bin.Buffer, limit int) ([]byte, func(), error) {
+	if limit <= 0 || limit > maxSingleGZIPExpandedBytes {
+		return nil, func() {}, fmt.Errorf("invalid gzip expansion limit %d", limit)
+	}
 	compressed, err := gzipPackedBytesView(b)
 	if err != nil {
 		return nil, func() {}, err
@@ -368,7 +407,7 @@ func (s *Server) decodeGZIPWithGlobalBudget(b *bin.Buffer) ([]byte, func(), erro
 		}
 	}
 	if s.frameBudget != nil {
-		reserved, err = s.frameBudget.reserve(maxSingleGZIPExpandedBytes, 0)
+		reserved, err = s.frameBudget.reserve(int64(limit), 0)
 		if err != nil {
 			return nil, func() {}, err
 		}
@@ -379,19 +418,22 @@ func (s *Server) decodeGZIPWithGlobalBudget(b *bin.Buffer) ([]byte, func(), erro
 		release()
 		return nil, func() {}, err
 	}
-	data, readErr := io.ReadAll(io.LimitReader(r, maxSingleGZIPExpandedBytes+1))
+	data, readErr := io.ReadAll(io.LimitReader(r, int64(limit)+1))
 	closeErr := r.Close()
 	if readErr != nil {
 		release()
-		return nil, func() {}, readErr
+		return nil, func() {}, &gzipExpansionWorkError{expanded: len(data), cause: readErr}
 	}
 	if closeErr != nil {
 		release()
-		return nil, func() {}, closeErr
+		return nil, func() {}, &gzipExpansionWorkError{expanded: len(data), cause: closeErr}
 	}
-	if len(data) > maxSingleGZIPExpandedBytes {
+	if len(data) > limit {
 		release()
-		return nil, func() {}, fmt.Errorf("gzip expansion %d exceeds %d", len(data), maxSingleGZIPExpandedBytes)
+		return nil, func() {}, &gzipExpansionWorkError{
+			expanded: len(data),
+			cause:    fmt.Errorf("%w: expansion %d exceeds %d", errGZIPExpansionLimit, len(data), limit),
+		}
 	}
 	if reserved > int64(len(data)) {
 		s.frameBudget.release(reserved - int64(len(data)))

internal/mtprotoedge/inbound_layer_rpc.go

@@ -25,6 +25,8 @@ var inboundLayerDecodeLimits = tlprofile.Limits{
 }
 
 var errDefaultLayerAdmission = errors.New("selected layer profile rejected naked RPC")
+var errLayerRPCGZIPCapacity = errors.New("exact layer gzip admission capacity exhausted")
+var errLayerRPCAdmissionCapability = errors.New("exact layer RPC admission capability unavailable")
 
 const (
 	maxLayerRPCDependencyIDs = 128
@@ -172,6 +174,68 @@ func layerRPCAdmissionReservationSize(wireBytes int) int {
 	return wireBytes*layerRPCAdmissionWireFactor + layerRPCAdmissionGraphSlack
 }
 
+// layerRPCGZIPExpansionBudget bridges transient process-wide expansion memory
+// to the durable scheduler charge of one exact typed request. sourceBytes is
+// conservative: it retains the original compressed wire plus every successful
+// expansion seen across nested envelopes or an authoritative-profile re-decode.
+type layerRPCGZIPExpansionBudget struct {
+	server               *Server
+	plan                 *inboundPlan
+	reservation          *inboundRPCBatchReservation
+	entry                int
+	baseSourceBytes      int
+	attemptExpandedBytes int
+	chargedSourceBytes   int
+}
+
+func (b *layerRPCGZIPExpansionBudget) beginAttempt() {
+	if b != nil {
+		b.attemptExpandedBytes = 0
+	}
+}
+
+func (b *layerRPCGZIPExpansionBudget) expand(wire []byte, admissionLimit int) ([]byte, func(), error) {
+	noop := func() {}
+	if b == nil || b.server == nil || b.plan == nil || b.reservation == nil {
+		return nil, noop, errors.New("invalid exact layer gzip expansion budget")
+	}
+	frameRemaining := maxDispatchExpandedBytes - b.plan.gzipExpandedBytes
+	limit := min(admissionLimit, frameRemaining)
+	if limit <= 0 {
+		return nil, noop, errors.Join(
+			errLayerRPCGZIPCapacity,
+			fmt.Errorf("cumulative gzip expansion reached %d bytes", maxDispatchExpandedBytes),
+		)
+	}
+	data, release, err := b.server.decodeGZIPWithGlobalBudgetLimit(&bin.Buffer{Buf: wire}, limit)
+	if err != nil {
+		if work := gzipExpansionWork(err); work > 0 {
+			b.plan.gzipExpandedBytes += work
+		}
+		if errors.Is(err, ErrInboundFrameBudgetExceeded) {
+			return nil, release, errors.Join(errLayerRPCGZIPCapacity, err)
+		}
+		if limit < admissionLimit && errors.Is(err, errGZIPExpansionLimit) {
+			return nil, release, errors.Join(errLayerRPCGZIPCapacity, err)
+		}
+		return nil, release, err
+	}
+	b.plan.gzipExpandedBytes += len(data)
+	b.attemptExpandedBytes += len(data)
+	targetSourceBytes := b.baseSourceBytes + b.attemptExpandedBytes
+	targetCharge := layerRPCAdmissionReservationSize(targetSourceBytes)
+	if targetSourceBytes > b.chargedSourceBytes {
+		if err := b.reservation.growEntry(b.entry, targetCharge); err != nil {
+			if errors.Is(err, ErrInboundRPCQueueFull) {
+				return nil, release, errors.Join(errLayerRPCGZIPCapacity, err)
+			}
+			return nil, release, err
+		}
+		b.chargedSourceBytes = targetSourceBytes
+	}
+	return data, release, nil
+}
+
 // prepareInboundLayerRPCBatch is the production API path. The whole container
 // reserves conservative task/materialization capacity before the first exact
 // decoder callback. Admission then classifies every request; fresh owners keep
@@ -217,15 +281,38 @@ func (s *Server) prepareInboundLayerRPCBatch(ctx context.Context, c *Conn, plan
 		return err
 	}
 	evidence := make([]layerRPCProfileEvidence, len(plan.items))
-	for _, index := range candidateItems {
+	decodeOptions := make([]tlprofile.AdmissionOptions, len(candidateItems))
+	expansionBudgets := make([]*layerRPCGZIPExpansionBudget, len(candidateItems))
+	materializationCapacity := false
+	for reservationIndex, index := range candidateItems {
 		item := &plan.items[index]
 		itemState := admissionCursor.state
 		existingProfile, existing := s.rpcResults.ExactAdmissionProfile(c.authKeyID, c.sessionID, item.msgID)
 		if existing {
 			itemState = LayerProfileSnapshot{Profile: existingProfile, Origin: LayerProfileExplicit}
 		}
-		admitted, method, err := s.decodeInboundLayerRPC(itemState, item.body)
+		expansionBudget := &layerRPCGZIPExpansionBudget{
+			server: s, plan: plan, reservation: reservation,
+			entry: reservationIndex, baseSourceBytes: len(item.body), chargedSourceBytes: len(item.body),
+		}
+		expansionBudgets[reservationIndex] = expansionBudget
+		options := tlprofile.AdmissionOptions{
+			Limits:     inboundLayerDecodeLimits,
+			ExpandGZIP: expansionBudget.expand,
+		}
+		decodeOptions[reservationIndex] = options
+		admitted, method, err := s.decodeInboundLayerRPCWithOptions(itemState, item.body, options)
 		if err != nil {
+			if errors.Is(err, errLayerRPCGZIPCapacity) {
+				materializationCapacity = true
+				break
+			}
+			if errors.Is(err, ErrConnClosed) || errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
+				return err
+			}
+			if errors.Is(err, errLayerRPCAdmissionCapability) {
+				return err
+			}
 			if terminal, recognized := wrappedDestroyAuthKeyTerminal(err); recognized {
 				if terminal.WireSize != bin.Word || !validWrappedDestroyAuthKeyChain(terminal) {
 					s.log.Debug("Wrapped destroy_auth_key terminal rejected",
@@ -278,6 +365,19 @@ func (s *Server) prepareInboundLayerRPCBatch(ctx context.Context, c *Conn, plan
 			}
 		}
 	}
+	if materializationCapacity {
+		for _, index := range candidateItems {
+			item := &plan.items[index]
+			item.kind = inboundItemCapacityError
+			item.admitted = tlprofile.Admission{}
+			c.metrics.InboundRPCDropped(s.typeName(item.typeID), "materialization_capacity")
+		}
+		if err := reservation.retain(nil, nil); err != nil {
+			return err
+		}
+		plan.rpcReservation = nil
+		return nil
+	}
 
 	var indices []int
 	var reservationIndices []int
@@ -304,7 +404,16 @@ func (s *Server) prepareInboundLayerRPCBatch(ctx context.Context, c *Conn, plan
 				item.admitted.Prepared().SemanticIdentity(),
 				item.admitted.Call().Identity(),
 			); candidate != nil {
-				claim, err := s.acquireAdmittedLayerRPC(c, item, &evidence[index])
+				claim, err := s.acquireAdmittedLayerRPC(
+					c, item, &evidence[index], decodeOptions[reservationIndex], expansionBudgets[reservationIndex],
+				)
+				if errors.Is(err, errLayerRPCGZIPCapacity) {
+					s.rpcRewrap.release(candidate)
+					c.metrics.InboundRPCDropped(candidate.method, "materialization_capacity")
+					flightCapacity = true
+					item.kind = inboundItemCapacityError
+					continue
+				}
 				if errors.Is(err, ErrRPCResultFlightCapacity) {
 					s.rpcRewrap.release(candidate)
 					c.metrics.InboundRPCDropped(candidate.method, "flight_capacity")
@@ -387,7 +496,15 @@ func (s *Server) prepareInboundLayerRPCBatch(ctx context.Context, c *Conn, plan
 			clearedPostInitCandidates = true
 		}
 
-		claim, err := s.acquireAdmittedLayerRPC(c, item, &evidence[index])
+		claim, err := s.acquireAdmittedLayerRPC(
+			c, item, &evidence[index], decodeOptions[reservationIndex], expansionBudgets[reservationIndex],
+		)
+		if errors.Is(err, errLayerRPCGZIPCapacity) {
+			c.metrics.InboundRPCDropped(method, "materialization_capacity")
+			flightCapacity = true
+			item.kind = inboundItemCapacityError
+			continue
+		}
 		if errors.Is(err, ErrRPCResultFlightCapacity) {
 			c.metrics.InboundRPCDropped(method, "flight_capacity")
 			flightCapacity = true
@@ -624,6 +741,8 @@ func (s *Server) acquireAdmittedLayerRPC(
 	c *Conn,
 	item *inboundItem,
 	evidence *layerRPCProfileEvidence,
+	options tlprofile.AdmissionOptions,
+	expansionBudget *layerRPCGZIPExpansionBudget,
 ) (rpcResultAcquire, error) {
 	if s == nil || c == nil || item == nil {
 		return rpcResultAcquire{}, ErrRPCResultFlightInvalid
@@ -652,9 +771,17 @@ func (s *Server) acquireAdmittedLayerRPC(
 		// mutation, not an inherited-default race.
 		return rpcResultAcquire{}, err
 	}
-	redecoded, method, decodeErr := s.decodeInboundLayerRPC(
+	// Drop the losing typed graph before materializing its authoritative-profile
+	// replacement. The grown reservation therefore needs to cover the larger
+	// graph, not two simultaneous copies.
+	item.admitted = tlprofile.Admission{}
+	if expansionBudget != nil {
+		expansionBudget.beginAttempt()
+	}
+	redecoded, method, decodeErr := s.decodeInboundLayerRPCWithOptions(
 		LayerProfileSnapshot{Profile: winnerProfile, Origin: LayerProfileExplicit},
 		item.body,
+		options,
 	)
 	if decodeErr != nil {
 		return rpcResultAcquire{}, decodeErr
@@ -786,6 +913,14 @@ func layerRPCAdmissionHasExplicitSelector(body []byte, admissionErr error) bool
 // evidence only after the full request identity has acquired an owner (or a
 // genuine new-msg_id rewrap alias).
 func (s *Server) decodeInboundLayerRPC(state LayerProfileSnapshot, body []byte) (tlprofile.Admission, string, error) {
+	return s.decodeInboundLayerRPCWithLimits(state, body, inboundLayerDecodeLimits)
+}
+
+func (s *Server) decodeInboundLayerRPCWithLimits(state LayerProfileSnapshot, body []byte, limits tlprofile.Limits) (tlprofile.Admission, string, error) {
+	return s.decodeInboundLayerRPCWithOptions(state, body, tlprofile.AdmissionOptions{Limits: limits})
+}
+
+func (s *Server) decodeInboundLayerRPCWithOptions(state LayerProfileSnapshot, body []byte, options tlprofile.AdmissionOptions) (tlprofile.Admission, string, error) {
 	if s == nil || s.layerRPC == nil || len(body) < bin.Word {
 		return tlprofile.Admission{}, "unknown", fmt.Errorf("invalid exact RPC admission input")
 	}
@@ -795,15 +930,30 @@ func (s *Server) decodeInboundLayerRPC(state LayerProfileSnapshot, body []byte)
 		err     error
 	)
 	if state.Origin != LayerProfileUnknown {
-		if admitter, ok := s.layerRPC.(LayerRPCDefaultProfileAdmitter); ok {
+		if admitter, ok := s.layerRPC.(LayerRPCDefaultProfileOptionsAdmitter); ok {
-			request, err = admitter.AdmitDefaultLayer(state.Profile, b, inboundLayerDecodeLimits)
+			request, err = admitter.AdmitDefaultLayerWithOptions(state.Profile, b, options)
+		} else if admitter, ok := s.layerRPC.(LayerRPCDefaultProfileAdmitter); ok {
+			// Preserve the stable pre-options capability first: unlike strict
+			// exact admission, default admission lets an explicit invokeWithLayer
+			// correct inherited or restored profile evidence.
+			request, err = admitter.AdmitDefaultLayer(state.Profile, b, options.Limits)
+		} else if admitter, ok := s.layerRPC.(LayerRPCOptionsAdmitter); ok {
+			request, err = admitter.AdmitLayerWithOptions(state.Profile, b, options)
 		} else {
-			// Compatibility fallback for old package tests/mocks. Production Router
+			request, err = s.layerRPC.AdmitLayer(state.Profile, b, options.Limits)
-			// implements default admission so explicit invokeWithLayer can correct.
-			request, err = s.layerRPC.AdmitLayer(state.Profile, b, inboundLayerDecodeLimits)
 		}
+	} else if admitter, ok := s.layerRPC.(LayerRPCOptionsAdmitter); ok {
+		request, err = admitter.AdmitUnprofiledWithOptions(b, options)
 	} else {
-		request, err = s.layerRPC.AdmitUnprofiled(b, inboundLayerDecodeLimits)
+		request, err = s.layerRPC.AdmitUnprofiled(b, options.Limits)
+	}
+	if err != nil && options.ExpandGZIP != nil && errors.Is(err, tlprofile.ErrGZIPExpanderMissing) {
+		// A handler compiled against the stable Limits-only boundary remains
+		// valid for plain requests. Encountering gzip_packed without the optional
+		// capability is instead a server wiring/programming error: returning the
+		// generated error as INPUT_REQUEST_INVALID would silently blame a valid
+		// client envelope and make recovery impossible.
+		err = fmt.Errorf("%w: handler cannot use caller-owned bounded gzip expansion: %w", errLayerRPCAdmissionCapability, err)
 	}
 	method := "unknown"
 	if err == nil {
@@ -847,6 +997,10 @@ func (s *Server) decodeInboundLayerRPC(state LayerProfileSnapshot, body []byte)
 			method = s.typeName(codecErr.WireID)
 		}
 	}
+	var unknownTerminal *tlprofile.UnknownTerminalError
+	if errors.As(err, &unknownTerminal) && unknownTerminal.WireID != 0 {
+		method = s.typeName(unknownTerminal.WireID)
+	}
 	if errors.Is(err, tlprofile.ErrUnknownRPCMethod) && s.log != nil {
 		if terminal, recognized := wrappedDestroyAuthKeyTerminal(err); recognized {
 			method = "destroy_auth_key"

internal/mtprotoedge/inbound_layer_rpc_test.go

@@ -1,6 +1,7 @@
 package mtprotoedge
 
 import (
+	"bytes"
 	"context"
 	"errors"
 	"fmt"
@@ -46,6 +47,14 @@ type admissionOnlyLayerRPC struct {
 	published  []publishedLayerEvidence
 }
 
+// legacyAdmissionOnlyLayerRPC intentionally exposes only the original
+// Limits-based admission interfaces. It guards source and runtime compatibility
+// for implementations compiled before caller-owned AdmissionOptions existed.
+type legacyAdmissionOnlyLayerRPC struct {
+	dispatcher    *tlprofile.Dispatcher
+	lastRemaining int
+}
+
 type orderedAdmissionOnlyLayerRPC struct {
 	*admissionOnlyLayerRPC
 	exactMu sync.Mutex
@@ -221,6 +230,10 @@ func newAdmissionOnlyLayerRPC() *admissionOnlyLayerRPC {
 	return &admissionOnlyLayerRPC{dispatcher: tlprofile.NewDispatcher()}
 }
 
+func newLegacyAdmissionOnlyLayerRPC() *legacyAdmissionOnlyLayerRPC {
+	return &legacyAdmissionOnlyLayerRPC{dispatcher: tlprofile.NewDispatcher()}
+}
+
 func newOrderedAdmissionOnlyLayerRPC() *orderedAdmissionOnlyLayerRPC {
 	return &orderedAdmissionOnlyLayerRPC{
 		admissionOnlyLayerRPC: newAdmissionOnlyLayerRPC(),
@@ -265,14 +278,48 @@ func (h *admissionOnlyLayerRPC) AdmitLayer(profile tlprofile.Profile, b *bin.Buf
 	return h.dispatcher.Admit(profile, b, limits)
 }
 
+func (h *admissionOnlyLayerRPC) AdmitLayerWithOptions(profile tlprofile.Profile, b *bin.Buffer, options tlprofile.AdmissionOptions) (tlprofile.Admission, error) {
+	return h.dispatcher.AdmitWithOptions(profile, b, options)
+}
+
 func (h *admissionOnlyLayerRPC) AdmitDefaultLayer(profile tlprofile.Profile, b *bin.Buffer, limits tlprofile.Limits) (tlprofile.Admission, error) {
 	return h.dispatcher.AdmitDefault(profile, b, limits)
 }
 
+func (h *admissionOnlyLayerRPC) AdmitDefaultLayerWithOptions(profile tlprofile.Profile, b *bin.Buffer, options tlprofile.AdmissionOptions) (tlprofile.Admission, error) {
+	return h.dispatcher.AdmitDefaultWithOptions(profile, b, options)
+}
+
 func (h *admissionOnlyLayerRPC) AdmitUnprofiled(b *bin.Buffer, limits tlprofile.Limits) (tlprofile.Admission, error) {
 	return h.dispatcher.AdmitUnprofiled(b, limits)
 }
 
+func (h *admissionOnlyLayerRPC) AdmitUnprofiledWithOptions(b *bin.Buffer, options tlprofile.AdmissionOptions) (tlprofile.Admission, error) {
+	return h.dispatcher.AdmitUnprofiledWithOptions(b, options)
+}
+
+func (h *legacyAdmissionOnlyLayerRPC) AdmitLayer(profile tlprofile.Profile, b *bin.Buffer, limits tlprofile.Limits) (tlprofile.Admission, error) {
+	request, err := h.dispatcher.Admit(profile, b, limits)
+	h.lastRemaining = b.Len()
+	return request, err
+}
+
+func (h *legacyAdmissionOnlyLayerRPC) AdmitDefaultLayer(profile tlprofile.Profile, b *bin.Buffer, limits tlprofile.Limits) (tlprofile.Admission, error) {
+	request, err := h.dispatcher.AdmitDefault(profile, b, limits)
+	h.lastRemaining = b.Len()
+	return request, err
+}
+
+func (h *legacyAdmissionOnlyLayerRPC) AdmitUnprofiled(b *bin.Buffer, limits tlprofile.Limits) (tlprofile.Admission, error) {
+	request, err := h.dispatcher.AdmitUnprofiled(b, limits)
+	h.lastRemaining = b.Len()
+	return request, err
+}
+
+func (*legacyAdmissionOnlyLayerRPC) DispatchAdmitted(context.Context, [8]byte, int64, int64, uint64, tlprofile.Admission) (tlprofile.Result, string, error) {
+	return nil, "", fmt.Errorf("admission-only handler")
+}
+
 func (*admissionOnlyLayerRPC) DispatchAdmitted(context.Context, [8]byte, int64, int64, uint64, tlprofile.Admission) (tlprofile.Result, string, error) {
 	return nil, "", fmt.Errorf("admission-only handler")
 }
@@ -301,6 +348,99 @@ func (h *admissionOnlyLayerRPC) publications() []publishedLayerEvidence {
 	return append([]publishedLayerEvidence(nil), h.published...)
 }
 
+func TestLegacyLayerRPCAdmissionInterfacesRemainCompatible(t *testing.T) {
+	t.Run("inherited default accepts explicit correction", func(t *testing.T) {
+		handler := newLegacyAdmissionOnlyLayerRPC()
+		s := New(Options{DC: 2, LayerRPC: handler})
+		body := exactLayerRPCBody(t, &tg.InvokeWithLayerRequest{
+			Layer: 225,
+			Query: &tg.HelpGetConfigRequest{},
+		})
+
+		request, method, err := s.decodeInboundLayerRPCWithOptions(
+			LayerProfileSnapshot{Profile: tlprofile.Profile228, Origin: LayerProfileInherited},
+			body,
+			tlprofile.AdmissionOptions{
+				Limits: inboundLayerDecodeLimits,
+				ExpandGZIP: func([]byte, int) ([]byte, func(), error) {
+					t.Fatal("plain legacy admission unexpectedly requested gzip expansion")
+					return nil, nil, nil
+				},
+			},
+		)
+		if err != nil {
+			t.Fatalf("legacy default admission: %v", err)
+		}
+		if method != "help.getConfig" {
+			t.Fatalf("method = %q, want help.getConfig", method)
+		}
+		if request.Call().Profile() != tlprofile.Profile225 {
+			t.Fatalf("call profile = %d, want 225", request.Call().Profile())
+		}
+		if profile, ok := request.ProfileEvidence(); !ok || profile != tlprofile.Profile225 {
+			t.Fatalf("profile evidence = %d/%v, want 225/true", profile, ok)
+		}
+		if handler.lastRemaining != 0 {
+			t.Fatalf("successful legacy admission left %d bytes", handler.lastRemaining)
+		}
+	})
+
+	t.Run("unprofiled selector remains supported", func(t *testing.T) {
+		handler := newLegacyAdmissionOnlyLayerRPC()
+		s := New(Options{DC: 2, LayerRPC: handler})
+		body := exactLayerRPCBody(t, &tg.InvokeWithLayerRequest{
+			Layer: 225,
+			Query: &tg.HelpGetNearestDCRequest{},
+		})
+
+		request, method, err := s.decodeInboundLayerRPCWithOptions(
+			LayerProfileSnapshot{},
+			body,
+			tlprofile.AdmissionOptions{Limits: inboundLayerDecodeLimits},
+		)
+		if err != nil {
+			t.Fatalf("legacy unprofiled admission: %v", err)
+		}
+		if method != "help.getNearestDc" {
+			t.Fatalf("method = %q, want help.getNearestDc", method)
+		}
+		if request.Call().Profile() != tlprofile.Profile225 {
+			t.Fatalf("call profile = %d, want 225", request.Call().Profile())
+		}
+	})
+
+	t.Run("nested gzip requires explicit optional capability", func(t *testing.T) {
+		handler := newLegacyAdmissionOnlyLayerRPC()
+		s := New(Options{DC: 2, LayerRPC: handler})
+		body, _ := tdlibNestedGZIPBody(t, tlprofile.Profile228, &tg.HelpGetConfigRequest{})
+		original := append([]byte(nil), body...)
+
+		_, _, err := s.decodeInboundLayerRPCWithOptions(
+			LayerProfileSnapshot{},
+			body,
+			tlprofile.AdmissionOptions{
+				Limits: inboundLayerDecodeLimits,
+				ExpandGZIP: func([]byte, int) ([]byte, func(), error) {
+					t.Fatal("legacy handler unexpectedly received options-only gzip expander")
+					return nil, nil, nil
+				},
+			},
+		)
+		if !errors.Is(err, errLayerRPCAdmissionCapability) {
+			t.Fatalf("nested gzip error = %v, want admission capability error", err)
+		}
+		if !errors.Is(err, tlprofile.ErrGZIPExpanderMissing) {
+			t.Fatalf("nested gzip error = %v, want generated missing-expander cause", err)
+		}
+		if handler.lastRemaining != len(body) {
+			t.Fatalf("failed legacy admission retained %d/%d input bytes", handler.lastRemaining, len(body))
+		}
+		if !bytes.Equal(body, original) {
+			t.Fatal("failed legacy admission mutated caller wire bytes")
+		}
+	})
+}
+
 func TestNestedExplicitLayerAdmissionErrorsAreNotDefaultFailures(t *testing.T) {
 	handler := newAdmissionOnlyLayerRPC()
 	s := New(Options{DC: 2, LayerRPC: handler})
@@ -833,11 +973,12 @@ func TestSameMsgIDNakedReplayUsesWinnerAdmissionProfile(t *testing.T) {
 	}
 	c220 := &Conn{authKeyID: authKeyID, sessionID: sessionID}
 	c227 := &Conn{authKeyID: authKeyID, sessionID: sessionID}
-	winner, err := s.acquireAdmittedLayerRPC(c220, &item220, nil)
+	options := tlprofile.AdmissionOptions{Limits: inboundLayerDecodeLimits}
+	winner, err := s.acquireAdmittedLayerRPC(c220, &item220, nil, options, nil)
 	if err != nil || winner.state != rpcResultAcquireOwner || winner.owner == nil {
 		t.Fatalf("winner = state:%d err:%v", winner.state, err)
 	}
-	loser, err := s.acquireAdmittedLayerRPC(c227, &item227, nil)
+	loser, err := s.acquireAdmittedLayerRPC(c227, &item227, nil, options, nil)
 	if err != nil || loser.state != rpcResultAcquirePending || loser.admissionSeq != winner.admissionSeq {
 		t.Fatalf("loser join = state:%d seq:%d err:%v, winner seq:%d", loser.state, loser.admissionSeq, err, winner.admissionSeq)
 	}
@@ -852,7 +993,7 @@ func TestSameMsgIDNakedReplayUsesWinnerAdmissionProfile(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if _, err := s.acquireAdmittedLayerRPC(c220, &changed, nil); !errors.Is(err, ErrRPCResultIdentityMismatch) {
+	if _, err := s.acquireAdmittedLayerRPC(c220, &changed, nil, options, nil); !errors.Is(err, ErrRPCResultIdentityMismatch) {
 		t.Fatalf("same-msg_id changed body err=%v, want identity mismatch", err)
 	}
 	winner.owner.Abort()

internal/mtprotoedge/inbound_preflight.go

@@ -92,6 +92,11 @@ type inboundPlan struct {
 	ackIDs     []int64
 	logicalMin int64
 	releases   []func()
+	// gzipExpandedBytes is the non-refundable per-frame decompression work
+	// already performed by outer and exact-layer nested gzip envelopes. Memory
+	// reservations are released when their buffers die, but this cumulative
+	// counter prevents sibling RPCs from recycling the same CPU budget.
+	gzipExpandedBytes int
 
 	rpcReservation *inboundRPCBatchReservation
 	rpcTasks       []inboundRPC
@@ -314,6 +319,7 @@ func (s *Server) preflightInbound(cs *connState, msgID int64, seqNo int32, body
 		plan.close()
 		return nil, err
 	}
+	plan.gzipExpandedBytes = budget.expanded
 	plan.staged = overlay.staged
 	if plan.logicalMin == 0 {
 		plan.close()

internal/mtprotoedge/inbound_rpc.go

@@ -4,6 +4,7 @@ import (
 	"container/list"
 	"context"
 	"errors"
+	"fmt"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -544,6 +545,60 @@ func (c *Conn) dropInboundRPCSpecs(specs []inboundRPCSpec, reason string) {
 	}
 }
 
+// growEntry raises one provisional task's materialization charge without a
+// release/reacquire window. Exact gzip admission calls this after the expanded
+// size is known but before the generated typed decoder can allocate the request
+// graph. A failure leaves every existing reservation unchanged so the caller
+// can reject and abort the whole container atomically.
+func (r *inboundRPCBatchReservation) growEntry(index, targetSize int) error {
+	if r == nil || index < 0 || index >= len(r.entries) || targetSize < 0 {
+		return errInboundRPCBatchSelection
+	}
+	entry := &r.entries[index]
+	if targetSize <= entry.size {
+		return nil
+	}
+	if entry.global == nil || entry.global.scheduler == nil || entry.global.released.Load() {
+		return ErrConnClosed
+	}
+	delta := int64(targetSize) - int64(entry.size)
+	scheduler := entry.global.scheduler
+	conn := r.conn
+
+	// Match initial admission's lock order: global scheduler budget, then the
+	// connection queue budget. Release paths never hold rpcMu while acquiring
+	// budgetMu, so this cannot invert task completion or close.
+	scheduler.budgetMu.Lock()
+	defer scheduler.budgetMu.Unlock()
+	select {
+	case <-scheduler.stopCh:
+		return ErrConnClosed
+	default:
+	}
+	if delta > scheduler.maxBytes-scheduler.bytes {
+		return fmt.Errorf("%w: grow exact admission global byte budget by %d", ErrInboundRPCQueueFull, delta)
+	}
+
+	conn.rpcMu.Lock()
+	defer conn.rpcMu.Unlock()
+	if err := r.ctx.Err(); err != nil {
+		return err
+	}
+	if conn.rpcClosed || conn.isRetired() {
+		return ErrConnClosed
+	}
+	if delta > int64(maxInflightRPCBytes)-conn.inflightRPCBytes.Load() {
+		return fmt.Errorf("%w: grow exact admission connection byte budget by %d", ErrInboundRPCQueueFull, delta)
+	}
+
+	scheduler.bytes += delta
+	entry.global.size += delta
+	entry.size = targetSize
+	r.totalSize += delta
+	conn.inflightRPCBytes.Add(delta)
+	return nil
+}
+
 // retain keeps a subset of a provisional batch on the original connection and
 // global reservations. Exact-layer admission uses this after typed decode has
 // classified completed replays, pending joins, admission errors, and fresh

internal/mtprotoedge/inbound_rpc_batch_test.go

@@ -130,6 +130,80 @@ func TestInboundRPCBatchAbortReturnsEveryReservationExactlyOnce(t *testing.T) {
 	}
 }
 
+func TestInboundRPCBatchReservationGrowTransfersBudgetAtomically(t *testing.T) {
+	scheduler := newInboundRPCScheduler(1, 8, 1<<20)
+	c := newInboundTestConn(scheduler, 1, 4, time.Second)
+	defer func() {
+		c.closeInboundRPCScheduler()
+		scheduler.stop(time.Second)
+	}()
+
+	reservation, err := c.reserveInboundRPCBatch(context.Background(), []inboundRPCSpec{
+		{method: "one", size: 3},
+		{method: "two", size: 5},
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := reservation.growEntry(0, 11); err != nil {
+		t.Fatal(err)
+	}
+	if tasks, bytes := scheduler.budgetSnapshot(); tasks != 2 || bytes != 16 {
+		t.Fatalf("grown global budget = %d/%d, want 2/16", tasks, bytes)
+	}
+	if got := c.inflightRPCBytes.Load(); got != 16 {
+		t.Fatalf("grown connection budget = %d, want 16", got)
+	}
+	if reservation.entries[0].size != 11 || reservation.totalSize != 16 {
+		t.Fatalf("grown reservation entry/total = %d/%d", reservation.entries[0].size, reservation.totalSize)
+	}
+	reservation.abort()
+	if tasks, bytes := scheduler.budgetSnapshot(); tasks != 0 || bytes != 0 {
+		t.Fatalf("grown reservation abort leaked global budget %d/%d", tasks, bytes)
+	}
+	if got := c.inflightRPCBytes.Load(); got != 0 {
+		t.Fatalf("grown reservation abort leaked connection budget %d", got)
+	}
+}
+
+func TestInboundRPCBatchReservationGrowFailureKeepsOriginalBudget(t *testing.T) {
+	for _, test := range []struct {
+		name       string
+		globalMax  int64
+		targetSize int
+	}{
+		{name: "global", globalMax: 5, targetSize: 6},
+		{name: "connection", globalMax: int64(maxInflightRPCBytes) * 2, targetSize: maxInflightRPCBytes + 1},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			scheduler := newInboundRPCScheduler(1, 8, test.globalMax)
+			c := newInboundTestConn(scheduler, 1, 4, time.Second)
+			defer func() {
+				c.closeInboundRPCScheduler()
+				scheduler.stop(time.Second)
+			}()
+
+			reservation, err := c.reserveInboundRPCBatch(context.Background(), []inboundRPCSpec{{method: "one", size: 3}})
+			if err != nil {
+				t.Fatal(err)
+			}
+			if err := reservation.growEntry(0, test.targetSize); !errors.Is(err, ErrInboundRPCQueueFull) {
+				t.Fatalf("grow error = %v, want ErrInboundRPCQueueFull", err)
+			}
+			if tasks, bytes := scheduler.budgetSnapshot(); tasks != 1 || bytes != 3 {
+				t.Fatalf("failed grow changed global budget %d/%d", tasks, bytes)
+			}
+			if got := c.inflightRPCBytes.Load(); got != 3 {
+				t.Fatalf("failed grow changed connection budget %d", got)
+			}
+			if reservation.entries[0].size != 3 || reservation.totalSize != 3 {
+				t.Fatalf("failed grow changed reservation entry/total = %d/%d", reservation.entries[0].size, reservation.totalSize)
+			}
+			reservation.abort()
+		})
+	}
+}
+
 func TestInboundRPCBatchCommitAppendsAllAndSchedulesAtomically(t *testing.T) {
 	scheduler := newInboundRPCScheduler(1, 8, 1<<20)
 	c := newInboundTestConn(scheduler, 1, 4, time.Second)

internal/mtprotoedge/layer_admission_budget_test.go

@@ -11,6 +11,7 @@ import (
 
 	"github.com/iamxvbaba/td/bin"
 	"github.com/iamxvbaba/td/clock"
+	"github.com/iamxvbaba/td/proto"
 	"github.com/iamxvbaba/td/tg"
 	"go.uber.org/zap/zaptest"
 
@@ -113,11 +114,27 @@ func (h *countingLayerRPCAdmission) AdmitLayer(profile tlprofile.Profile, b *bin
 	return h.LayerRPCHandler.AdmitLayer(profile, b, limits)
 }
 
+func (h *countingLayerRPCAdmission) AdmitLayerWithOptions(profile tlprofile.Profile, b *bin.Buffer, options tlprofile.AdmissionOptions) (tlprofile.Admission, error) {
+	h.decodeCalls.Add(1)
+	if admitter, ok := h.LayerRPCHandler.(LayerRPCOptionsAdmitter); ok {
+		return admitter.AdmitLayerWithOptions(profile, b, options)
+	}
+	return h.LayerRPCHandler.AdmitLayer(profile, b, options.Limits)
+}
+
 func (h *countingLayerRPCAdmission) AdmitUnprofiled(b *bin.Buffer, limits tlprofile.Limits) (tlprofile.Admission, error) {
 	h.decodeCalls.Add(1)
 	return h.LayerRPCHandler.AdmitUnprofiled(b, limits)
 }
 
+func (h *countingLayerRPCAdmission) AdmitUnprofiledWithOptions(b *bin.Buffer, options tlprofile.AdmissionOptions) (tlprofile.Admission, error) {
+	h.decodeCalls.Add(1)
+	if admitter, ok := h.LayerRPCHandler.(LayerRPCOptionsAdmitter); ok {
+		return admitter.AdmitUnprofiledWithOptions(b, options)
+	}
+	return h.LayerRPCHandler.AdmitUnprofiled(b, options.Limits)
+}
+
 func TestLayerRPCAdmissionCapacityRejectsBeforeDecoder(t *testing.T) {
 	for _, test := range []struct {
 		name       string
@@ -162,6 +179,209 @@ func TestLayerRPCAdmissionCapacityRejectsBeforeDecoder(t *testing.T) {
 	}
 }
 
+func TestLayerRPCAdmissionExpandsTDLibNestedGZIPUnderTransferredBudget(t *testing.T) {
+	router := rpc.New(rpc.Config{DC: 2}, rpc.Deps{}, zaptest.NewLogger(t), clock.System)
+	s := New(Options{DC: 2, LayerRPC: router, Logger: zaptest.NewLogger(t)})
+	c := &Conn{authKeyID: [8]byte{8, 21}, sessionID: 821, metrics: NopMetrics{}}
+	c.startInboundRPCScheduler(s.rpcScheduler, 1, 4, time.Second)
+	defer func() {
+		c.closeInboundRPCScheduler()
+		s.rpcScheduler.stop(time.Second)
+	}()
+
+	body, expandedBytes := tdlibNestedGZIPBody(t, tlprofile.Profile228, &tg.HelpGetConfigRequest{})
+	plan := &inboundPlan{items: []inboundItem{{kind: inboundItemRPC, msgID: 100, body: body}}}
+	defer plan.close()
+	if err := s.prepareInboundLayerRPCBatch(context.Background(), c, plan); err != nil {
+		t.Fatal(err)
+	}
+	if plan.items[0].kind != inboundItemRPC || plan.rpcReservation == nil || len(plan.rpcTasks) != 1 {
+		t.Fatalf("admitted nested gzip plan = kind:%d reservation:%v tasks:%d", plan.items[0].kind, plan.rpcReservation != nil, len(plan.rpcTasks))
+	}
+	wantCharge := int64(layerRPCAdmissionReservationSize(len(body) + expandedBytes))
+	if got := c.inflightRPCBytes.Load(); got != wantCharge {
+		t.Fatalf("nested gzip connection charge = %d, want %d", got, wantCharge)
+	}
+	if got := plan.rpcReservation.entries[0].size; int64(got) != wantCharge {
+		t.Fatalf("nested gzip reservation charge = %d, want %d", got, wantCharge)
+	}
+	if got := plan.gzipExpandedBytes; got != expandedBytes {
+		t.Fatalf("nested gzip cumulative expansion = %d, want %d", got, expandedBytes)
+	}
+	if got := s.frameBudget.usedBytes(); got != 0 {
+		t.Fatalf("nested gzip temporary frame budget retained after materialization: %d", got)
+	}
+}
+
+func TestLayerRPCAdmissionNestedGZIPGrowFailureRejectsWholeBatch(t *testing.T) {
+	router := rpc.New(rpc.Config{DC: 2}, rpc.Deps{}, zaptest.NewLogger(t), clock.System)
+	s := New(Options{DC: 2, LayerRPC: router, Logger: zaptest.NewLogger(t)})
+	first, _ := tdlibNestedGZIPBody(t, tlprofile.Profile228, &tg.HelpGetConfigRequest{})
+	second, _ := tdlibNestedGZIPBody(t, tlprofile.Profile228, &tg.HelpGetNearestDCRequest{})
+	initialCharge := int64(layerRPCAdmissionReservationSize(len(first)) + layerRPCAdmissionReservationSize(len(second)))
+	s.rpcScheduler = newInboundRPCScheduler(1, 4, initialCharge)
+	c := &Conn{authKeyID: [8]byte{8, 22}, sessionID: 822, metrics: NopMetrics{}}
+	c.startInboundRPCScheduler(s.rpcScheduler, 1, 4, time.Second)
+	defer func() {
+		c.closeInboundRPCScheduler()
+		s.rpcScheduler.stop(time.Second)
+	}()
+
+	plan := &inboundPlan{items: []inboundItem{
+		{kind: inboundItemRPC, msgID: 100, body: first},
+		{kind: inboundItemRPC, msgID: 104, body: second},
+	}}
+	defer plan.close()
+	if err := s.prepareInboundLayerRPCBatch(context.Background(), c, plan); err != nil {
+		t.Fatal(err)
+	}
+	for index := range plan.items {
+		if plan.items[index].kind != inboundItemCapacityError {
+			t.Fatalf("item %d kind = %d, want capacity error", index, plan.items[index].kind)
+		}
+	}
+	if plan.rpcReservation != nil || len(plan.rpcTasks) != 0 {
+		t.Fatalf("capacity plan retained reservation/tasks = %v/%d", plan.rpcReservation != nil, len(plan.rpcTasks))
+	}
+	if got := c.inflightRPCBytes.Load(); got != 0 {
+		t.Fatalf("grow failure leaked connection charge %d", got)
+	}
+	if tasks, bytes := s.rpcScheduler.budgetSnapshot(); tasks != 0 || bytes != 0 {
+		t.Fatalf("grow failure leaked global budget %d/%d", tasks, bytes)
+	}
+	if got := s.frameBudget.usedBytes(); got != 0 {
+		t.Fatalf("grow failure leaked temporary frame budget %d", got)
+	}
+}
+
+func TestLayerRPCAdmissionNestedGZIPSiblingsShareFrameExpansionLimit(t *testing.T) {
+	router := rpc.New(rpc.Config{DC: 2}, rpc.Deps{}, zaptest.NewLogger(t), clock.System)
+	s := New(Options{DC: 2, LayerRPC: router, Logger: zaptest.NewLogger(t)})
+	c := &Conn{authKeyID: [8]byte{8, 23}, sessionID: 823, metrics: NopMetrics{}}
+	c.startInboundRPCScheduler(s.rpcScheduler, 1, 4, time.Second)
+	defer func() {
+		c.closeInboundRPCScheduler()
+		s.rpcScheduler.stop(time.Second)
+	}()
+
+	first, expandedBytes := tdlibNestedGZIPBody(t, tlprofile.Profile228, &tg.HelpGetConfigRequest{})
+	second, _ := tdlibNestedGZIPBody(t, tlprofile.Profile228, &tg.HelpGetNearestDCRequest{})
+	plan := &inboundPlan{
+		gzipExpandedBytes: maxDispatchExpandedBytes - expandedBytes,
+		items: []inboundItem{
+			{kind: inboundItemRPC, msgID: 100, body: first},
+			{kind: inboundItemRPC, msgID: 104, body: second},
+		},
+	}
+	defer plan.close()
+	if err := s.prepareInboundLayerRPCBatch(context.Background(), c, plan); err != nil {
+		t.Fatal(err)
+	}
+	for index := range plan.items {
+		if plan.items[index].kind != inboundItemCapacityError {
+			t.Fatalf("item %d kind = %d, want capacity error", index, plan.items[index].kind)
+		}
+	}
+	if got := plan.gzipExpandedBytes; got != maxDispatchExpandedBytes {
+		t.Fatalf("shared cumulative expansion = %d, want %d", got, maxDispatchExpandedBytes)
+	}
+	if got := c.inflightRPCBytes.Load(); got != 0 {
+		t.Fatalf("shared-limit rejection leaked connection charge %d", got)
+	}
+	if got := s.frameBudget.usedBytes(); got != 0 {
+		t.Fatalf("shared-limit rejection leaked temporary frame budget %d", got)
+	}
+}
+
+func TestLayerRPCAdmissionNestedGZIPReDecodeReusesMaterializationCharge(t *testing.T) {
+	handler := newAdmissionOnlyLayerRPC()
+	s := New(Options{DC: 2, LayerRPC: handler, Logger: zaptest.NewLogger(t)})
+	s.rpcResults = newRPCResultCacheWithFlightLimit(time.Now, 8)
+	scheduler := newInboundRPCScheduler(1, 4, 1<<30)
+	s.rpcScheduler = scheduler
+	authKeyID := [8]byte{8, 24}
+	const sessionID = int64(824)
+	c225 := &Conn{authKeyID: authKeyID, sessionID: sessionID, metrics: NopMetrics{}}
+	c227 := &Conn{authKeyID: authKeyID, sessionID: sessionID, metrics: NopMetrics{}}
+	c225.startInboundRPCScheduler(scheduler, 1, 2, time.Second)
+	c227.startInboundRPCScheduler(scheduler, 1, 2, time.Second)
+	defer func() {
+		c225.closeInboundRPCScheduler()
+		c227.closeInboundRPCScheduler()
+		scheduler.stop(time.Second)
+	}()
+
+	terminal := exactOutboundLayerRPCBody(t, tlprofile.Profile225, &tg.MessagesGetHistoryRequest{
+		Peer: &tg.InputPeerSelf{}, Limit: 1,
+	})
+	body := exactLayerRPCBody(t, &tg.InvokeWithoutUpdatesRequest{Query: &proto.GZIP{Data: terminal}})
+	initialCharge := layerRPCAdmissionReservationSize(len(body))
+	reservation225, err := c225.reserveInboundRPCBatch(context.Background(), []inboundRPCSpec{{method: "messages.getHistory", size: initialCharge}})
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer reservation225.abort()
+	reservation227, err := c227.reserveInboundRPCBatch(context.Background(), []inboundRPCSpec{{method: "messages.getHistory", size: initialCharge}})
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer reservation227.abort()
+
+	plan225 := &inboundPlan{}
+	budget225 := &layerRPCGZIPExpansionBudget{
+		server: s, plan: plan225, reservation: reservation225,
+		baseSourceBytes: len(body), chargedSourceBytes: len(body),
+	}
+	options225 := tlprofile.AdmissionOptions{Limits: inboundLayerDecodeLimits, ExpandGZIP: budget225.expand}
+	item225 := inboundItem{msgID: 100, body: body}
+	item225.admitted, item225.method, err = s.decodeInboundLayerRPCWithOptions(
+		LayerProfileSnapshot{Profile: tlprofile.Profile225, Origin: LayerProfileInherited}, body, options225,
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	plan227 := &inboundPlan{}
+	budget227 := &layerRPCGZIPExpansionBudget{
+		server: s, plan: plan227, reservation: reservation227,
+		baseSourceBytes: len(body), chargedSourceBytes: len(body),
+	}
+	options227 := tlprofile.AdmissionOptions{Limits: inboundLayerDecodeLimits, ExpandGZIP: budget227.expand}
+	item227 := inboundItem{msgID: 100, body: body}
+	item227.admitted, item227.method, err = s.decodeInboundLayerRPCWithOptions(
+		LayerProfileSnapshot{Profile: tlprofile.Profile227, Origin: LayerProfileInherited}, body, options227,
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if item225.admitted.Prepared().Identity() == item227.admitted.Prepared().Identity() {
+		t.Fatal("test request identity is invariant; need authoritative-profile re-decode")
+	}
+
+	winner, err := s.acquireAdmittedLayerRPC(c225, &item225, nil, options225, budget225)
+	if err != nil || winner.state != rpcResultAcquireOwner || winner.owner == nil {
+		t.Fatalf("winner = state:%d err:%v", winner.state, err)
+	}
+	defer winner.owner.Abort()
+	loser, err := s.acquireAdmittedLayerRPC(c227, &item227, nil, options227, budget227)
+	if err != nil || loser.state != rpcResultAcquirePending {
+		t.Fatalf("loser = state:%d err:%v", loser.state, err)
+	}
+	if got := item227.admitted.Call().Profile(); got != tlprofile.Profile225 {
+		t.Fatalf("loser re-admitted profile = %d, want 225", got)
+	}
+	wantCharge := layerRPCAdmissionReservationSize(len(body) + len(terminal))
+	if got := reservation227.entries[0].size; got != wantCharge {
+		t.Fatalf("re-decode reservation charge = %d, want single-graph maximum %d", got, wantCharge)
+	}
+	if got := plan227.gzipExpandedBytes; got != 2*len(terminal) {
+		t.Fatalf("re-decode cumulative work = %d, want %d", got, 2*len(terminal))
+	}
+	if got := s.frameBudget.usedBytes(); got != 0 {
+		t.Fatalf("re-decode leaked temporary frame budget %d", got)
+	}
+}
+
 func TestLayerRPCAdmissionTransfersOriginalReservationToFreshOwner(t *testing.T) {
 	router := rpc.New(rpc.Config{DC: 2}, rpc.Deps{}, zaptest.NewLogger(t), clock.System)
 	s := New(Options{DC: 2, LayerRPC: router})
@@ -207,6 +427,25 @@ func TestLayerRPCAdmissionTransfersOriginalReservationToFreshOwner(t *testing.T)
 	}
 }
 
+func tdlibNestedGZIPBody(t *testing.T, profile tlprofile.Profile, terminal bin.Object) ([]byte, int) {
+	t.Helper()
+	terminalWire := exactOutboundLayerRPCBody(t, profile, terminal)
+	request := &tg.InvokeWithLayerRequest{
+		Layer: int(profile),
+		Query: &tg.InitConnectionRequest{
+			APIID:          1,
+			DeviceModel:    "android",
+			SystemVersion:  "test",
+			AppVersion:     "1.0",
+			SystemLangCode: "en",
+			LangPack:       "",
+			LangCode:       "en",
+			Query:          &proto.GZIP{Data: terminalWire},
+		},
+	}
+	return exactLayerRPCBody(t, request), len(terminalWire)
+}
+
 func TestLayerRPCAdmissionPendingReplayReleasesProvisionalEntry(t *testing.T) {
 	router := rpc.New(rpc.Config{DC: 2}, rpc.Deps{}, zaptest.NewLogger(t), clock.System)
 	s := New(Options{DC: 2, LayerRPC: router})

internal/mtprotoedge/server.go

@@ -70,6 +70,14 @@ type LayerRPCHandler interface {
 	) (tlprofile.Result, string, error)
 }
 
+// LayerRPCOptionsAdmitter extends the stable handler boundary with
+// caller-owned admission capabilities. Implementations that do not expose it
+// remain usable for requests that need only Limits.
+type LayerRPCOptionsAdmitter interface {
+	AdmitLayerWithOptions(profile tlprofile.Profile, b *bin.Buffer, options tlprofile.AdmissionOptions) (tlprofile.Admission, error)
+	AdmitUnprofiledWithOptions(b *bin.Buffer, options tlprofile.AdmissionOptions) (tlprofile.Admission, error)
+}
+
 // LayerRPCDefaultProfileAdmitter decodes with a recoverable inherited/default
 // profile. Production handlers should implement it with the same sparse
 // tlprofile dispatcher and semantic adapter registry used by AdmitLayer. The split keeps old
@@ -79,6 +87,12 @@ type LayerRPCDefaultProfileAdmitter interface {
 	AdmitDefaultLayer(profile tlprofile.Profile, b *bin.Buffer, limits tlprofile.Limits) (tlprofile.Admission, error)
 }
 
+// LayerRPCDefaultProfileOptionsAdmitter is the capability-aware form used when
+// exact admission needs caller-owned resources such as bounded gzip expansion.
+type LayerRPCDefaultProfileOptionsAdmitter interface {
+	AdmitDefaultLayerWithOptions(profile tlprofile.Profile, b *bin.Buffer, options tlprofile.AdmissionOptions) (tlprofile.Admission, error)
+}
+
 // LayerRPCSessionProfileResolver may restore an exact profile only when it was
 // previously proven for this same (auth_key_id, session_id). Auth-key-wide
 // device metadata is intentionally ineligible: a client upgrade can reuse its

internal/mtprotoedge/structural_limits_test.go

@@ -664,4 +664,24 @@ func TestGZIPExpansionUsesProcessBudgetBeforeDecode(t *testing.T) {
 	if got := s.frameBudget.usedBytes(); got != 0 {
 		t.Fatalf("released expansion budget = %d, want zero", got)
 	}
+
+	s.frameBudget = newInboundFrameBudget(2 * maxSingleGZIPExpandedBytes)
+	if _, release, err := s.decodeGZIPWithGlobalBudgetLimit(&wrapped, len(payload)-1); err == nil {
+		release()
+		t.Fatal("caller-bounded gzip decode accepted an oversized expansion")
+	} else if got := gzipExpansionWork(err); got != len(payload) {
+		t.Fatalf("caller-bounded rejected expansion work = %d, want %d", got, len(payload))
+	}
+	if got := s.frameBudget.usedBytes(); got != 0 {
+		t.Fatalf("caller-bounded rejection leaked %d bytes", got)
+	}
+
+	s.frameBudget = newInboundFrameBudget(int64(len(payload) - 1))
+	if _, release, err := s.decodeGZIPWithGlobalBudgetLimit(&wrapped, len(payload)); !errors.Is(err, ErrInboundFrameBudgetExceeded) {
+		release()
+		t.Fatalf("caller-bounded process budget error = %v, want ErrInboundFrameBudgetExceeded", err)
+	}
+	if got := s.frameBudget.usedBytes(); got != 0 {
+		t.Fatalf("caller-bounded reservation failure leaked %d bytes", got)
+	}
 }

internal/rpc/layer_dispatch.go

@@ -57,13 +57,17 @@ const layerRPCReplayRestoreTimeout = 5 * time.Second
 // touching auth/session stores. The MTProto edge must call it before acquiring
 // an RPC flight/cache slot or scheduling business work.
 func (r *Router) AdmitLayer(profile tlprofile.Profile, b *bin.Buffer, limits tlprofile.Limits) (tlprofile.Admission, error) {
+	return r.AdmitLayerWithOptions(profile, b, tlprofile.AdmissionOptions{Limits: limits})
+}
+
+func (r *Router) AdmitLayerWithOptions(profile tlprofile.Profile, b *bin.Buffer, options tlprofile.AdmissionOptions) (tlprofile.Admission, error) {
 	if r == nil || r.dispatcher == nil {
 		return tlprofile.Admission{}, internalErr()
 	}
 	if b == nil {
 		return tlprofile.Admission{}, inputRequestInvalidErr()
 	}
-	return r.dispatcher.Admit(profile, b, limits)
+	return r.dispatcher.AdmitWithOptions(profile, b, options)
 }
 
 // AdmitDefaultLayer admits a request using an inherited auth-key profile as
@@ -71,13 +75,17 @@ func (r *Router) AdmitLayer(profile tlprofile.Profile, b *bin.Buffer, limits tlp
 // same wrapper chain to correct that default. Generated admission preserves
 // the distinction through EffectiveProfile and ProfileEvidence.
 func (r *Router) AdmitDefaultLayer(profile tlprofile.Profile, b *bin.Buffer, limits tlprofile.Limits) (tlprofile.Admission, error) {
+	return r.AdmitDefaultLayerWithOptions(profile, b, tlprofile.AdmissionOptions{Limits: limits})
+}
+
+func (r *Router) AdmitDefaultLayerWithOptions(profile tlprofile.Profile, b *bin.Buffer, options tlprofile.AdmissionOptions) (tlprofile.Admission, error) {
 	if r == nil || r.dispatcher == nil {
 		return tlprofile.Admission{}, internalErr()
 	}
 	if b == nil {
 		return tlprofile.Admission{}, inputRequestInvalidErr()
 	}
-	return r.dispatcher.AdmitDefault(profile, b, limits)
+	return r.dispatcher.AdmitDefaultWithOptions(profile, b, options)
 }
 
 // registerAndroidLayerRPCAdapter installs the only client-private schema seam.
@@ -191,10 +199,14 @@ func (r *Router) PrepareAdmittedReplay(
 // a closed terminal whose complete request and result wire graphs were proven
 // invariant across every generated profile. The latter never freezes a layer.
 func (r *Router) AdmitUnprofiled(b *bin.Buffer, limits tlprofile.Limits) (tlprofile.Admission, error) {
+	return r.AdmitUnprofiledWithOptions(b, tlprofile.AdmissionOptions{Limits: limits})
+}
+
+func (r *Router) AdmitUnprofiledWithOptions(b *bin.Buffer, options tlprofile.AdmissionOptions) (tlprofile.Admission, error) {
 	if r == nil || r.dispatcher == nil {
 		return tlprofile.Admission{}, internalErr()
 	}
-	return r.dispatcher.AdmitUnprofiled(b, limits)
+	return r.dispatcher.AdmitUnprofiledWithOptions(b, options)
 }
 
 // DispatchAdmitted executes one generated admission lease. invokeAfterMsg(s)