snapshot: sagernet/gvisor v0.0.0-20250811.0-sing-box-mod.1

Содержимое пина, зафиксированного в go.mod sing-box-lx, одним коммитом
без истории. Полная история SagerNet/gvisor — 1.45 ГБ и клонируется в
каждой CI-джобе; наша дельта — одна вставка в одну функцию, история для
неё не нужна.

Module path github.com/sagernet/gvisor сохранён намеренно: на него
опирается replace-директива суперпроекта.

Патч поверх — отдельным коммитом, чтобы дельта читалась одним git show
и переносилась на новый пин копированием.

SPECS/TASKS/048-GVISOR_HANDSHAKE_NIL_CRASH

pkg/tcpip/link/nested/nested.go

@@ -0,0 +1,185 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package nested provides helpers to implement the pattern of nested
+// stack.LinkEndpoints.
+package nested
+
+import (
+	"github.com/sagernet/gvisor/pkg/sync"
+	"github.com/sagernet/gvisor/pkg/tcpip"
+	"github.com/sagernet/gvisor/pkg/tcpip/header"
+	"github.com/sagernet/gvisor/pkg/tcpip/stack"
+)
+
+// Endpoint is a wrapper around stack.LinkEndpoint and stack.NetworkDispatcher
+// that can be used to implement nesting safely by providing lifecycle
+// concurrency guards.
+//
+// See the tests in this package for example usage.
+//
+// +stateify savable
+type Endpoint struct {
+	child    stack.LinkEndpoint
+	embedder stack.NetworkDispatcher
+
+	// mu protects dispatcher.
+	mu         sync.RWMutex `state:"nosave"`
+	dispatcher stack.NetworkDispatcher
+}
+
+var (
+	_ stack.GSOEndpoint       = (*Endpoint)(nil)
+	_ stack.LinkEndpoint      = (*Endpoint)(nil)
+	_ stack.NetworkDispatcher = (*Endpoint)(nil)
+)
+
+// Init initializes a nested.Endpoint that uses embedder as the dispatcher for
+// child on Attach.
+//
+// See the tests in this package for example usage.
+func (e *Endpoint) Init(child stack.LinkEndpoint, embedder stack.NetworkDispatcher) {
+	e.child = child
+	e.embedder = embedder
+}
+
+// DeliverNetworkPacket implements stack.NetworkDispatcher.
+func (e *Endpoint) DeliverNetworkPacket(protocol tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) {
+	e.mu.RLock()
+	d := e.dispatcher
+	e.mu.RUnlock()
+	if d != nil {
+		d.DeliverNetworkPacket(protocol, pkt)
+	}
+}
+
+// DeliverLinkPacket implements stack.NetworkDispatcher.
+func (e *Endpoint) DeliverLinkPacket(protocol tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) {
+	e.mu.RLock()
+	d := e.dispatcher
+	e.mu.RUnlock()
+	if d != nil {
+		d.DeliverLinkPacket(protocol, pkt)
+	}
+}
+
+// Attach implements stack.LinkEndpoint.
+func (e *Endpoint) Attach(dispatcher stack.NetworkDispatcher) {
+	e.mu.Lock()
+	e.dispatcher = dispatcher
+	e.mu.Unlock()
+	// If we're attaching to a valid dispatcher, pass embedder as the dispatcher
+	// to our child, otherwise detach the child by giving it a nil dispatcher.
+	var pass stack.NetworkDispatcher
+	if dispatcher != nil {
+		pass = e.embedder
+	}
+	e.child.Attach(pass)
+}
+
+// IsAttached implements stack.LinkEndpoint.
+func (e *Endpoint) IsAttached() bool {
+	e.mu.RLock()
+	isAttached := e.dispatcher != nil
+	e.mu.RUnlock()
+	return isAttached
+}
+
+// MTU implements stack.LinkEndpoint.
+func (e *Endpoint) MTU() uint32 {
+	return e.child.MTU()
+}
+
+// SetMTU implements stack.LinkEndpoint.
+func (e *Endpoint) SetMTU(mtu uint32) {
+	e.child.SetMTU(mtu)
+}
+
+// Capabilities implements stack.LinkEndpoint.
+func (e *Endpoint) Capabilities() stack.LinkEndpointCapabilities {
+	return e.child.Capabilities()
+}
+
+// MaxHeaderLength implements stack.LinkEndpoint.
+func (e *Endpoint) MaxHeaderLength() uint16 {
+	return e.child.MaxHeaderLength()
+}
+
+// LinkAddress implements stack.LinkEndpoint.
+func (e *Endpoint) LinkAddress() tcpip.LinkAddress {
+	return e.child.LinkAddress()
+}
+
+// SetLinkAddress implements stack.LinkEndpoint.SetLinkAddress.
+func (e *Endpoint) SetLinkAddress(addr tcpip.LinkAddress) {
+	e.mu.Lock()
+	defer e.mu.Unlock()
+	e.child.SetLinkAddress(addr)
+}
+
+// WritePackets implements stack.LinkEndpoint.
+func (e *Endpoint) WritePackets(pkts stack.PacketBufferList) (int, tcpip.Error) {
+	return e.child.WritePackets(pkts)
+}
+
+// Wait implements stack.LinkEndpoint.
+func (e *Endpoint) Wait() {
+	e.child.Wait()
+}
+
+// GSOMaxSize implements stack.GSOEndpoint.
+func (e *Endpoint) GSOMaxSize() uint32 {
+	if e, ok := e.child.(stack.GSOEndpoint); ok {
+		return e.GSOMaxSize()
+	}
+	return 0
+}
+
+// SupportedGSO implements stack.GSOEndpoint.
+func (e *Endpoint) SupportedGSO() stack.SupportedGSO {
+	if e, ok := e.child.(stack.GSOEndpoint); ok {
+		return e.SupportedGSO()
+	}
+	return stack.GSONotSupported
+}
+
+// ARPHardwareType implements stack.LinkEndpoint.ARPHardwareType
+func (e *Endpoint) ARPHardwareType() header.ARPHardwareType {
+	return e.child.ARPHardwareType()
+}
+
+// AddHeader implements stack.LinkEndpoint.AddHeader.
+func (e *Endpoint) AddHeader(pkt *stack.PacketBuffer) {
+	e.child.AddHeader(pkt)
+}
+
+// ParseHeader implements stack.LinkEndpoint.ParseHeader.
+func (e *Endpoint) ParseHeader(pkt *stack.PacketBuffer) bool {
+	return e.child.ParseHeader(pkt)
+}
+
+// Close implements stack.LinkEndpoint.
+func (e *Endpoint) Close() {
+	e.child.Close()
+}
+
+// SetOnCloseAction implement stack.LinkEndpoints.
+func (e *Endpoint) SetOnCloseAction(action func()) {
+	e.child.SetOnCloseAction(action)
+}
+
+// Child returns the child endpoint.
+func (e *Endpoint) Child() stack.LinkEndpoint {
+	return e.child
+}