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/waitable/waitable.go

@@ -0,0 +1,196 @@
+// Copyright 2018 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 waitable provides the implementation of data-link layer endpoints
+// that wrap other endpoints, and can wait for inflight calls to WritePacket or
+// DeliverNetworkPacket to finish (and new ones to be prevented).
+//
+// Waitable endpoints can be used in the networking stack by calling New(eID) to
+// create a new endpoint, where eID is the ID of the endpoint being wrapped,
+// and then passing it as an argument to Stack.CreateNIC().
+package waitable
+
+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"
+)
+
+var (
+	_ stack.NetworkDispatcher = (*Endpoint)(nil)
+	_ stack.LinkEndpoint      = (*Endpoint)(nil)
+)
+
+// Endpoint is a waitable link-layer endpoint.
+//
+// +stateify savable
+type Endpoint struct {
+	dispatchGate sync.Gate
+
+	mu endpointRWMutex `state:"nosave"`
+	// +checklocks:mu
+	dispatcher stack.NetworkDispatcher
+
+	writeGate sync.Gate
+	lower     stack.LinkEndpoint
+}
+
+// New creates a new waitable link-layer endpoint. It wraps around another
+// endpoint and allows the caller to block new write/dispatch calls and wait for
+// the inflight ones to finish before returning.
+func New(lower stack.LinkEndpoint) *Endpoint {
+	return &Endpoint{
+		lower: lower,
+	}
+}
+
+// DeliverNetworkPacket implements stack.NetworkDispatcher.DeliverNetworkPacket.
+// It is called by the link-layer endpoint being wrapped when a packet arrives,
+// and only forwards to the actual dispatcher if Wait or WaitDispatch haven't
+// been called.
+func (e *Endpoint) DeliverNetworkPacket(protocol tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) {
+	if !e.dispatchGate.Enter() {
+		return
+	}
+	e.mu.RLock()
+	d := e.dispatcher
+	e.mu.RUnlock()
+	if d != nil {
+		d.DeliverNetworkPacket(protocol, pkt)
+	}
+	e.dispatchGate.Leave()
+}
+
+// DeliverLinkPacket implements stack.NetworkDispatcher.
+func (e *Endpoint) DeliverLinkPacket(protocol tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) {
+	if !e.dispatchGate.Enter() {
+		return
+	}
+	e.mu.RLock()
+	d := e.dispatcher
+	e.mu.RUnlock()
+	if d != nil {
+		d.DeliverLinkPacket(protocol, pkt)
+	}
+	e.dispatchGate.Leave()
+}
+
+// Attach implements stack.LinkEndpoint.Attach. It saves the dispatcher and
+// registers with the lower endpoint as its dispatcher so that "e" is called
+// for inbound packets.
+func (e *Endpoint) Attach(dispatcher stack.NetworkDispatcher) {
+	e.mu.Lock()
+	e.dispatcher = dispatcher
+	e.mu.Unlock()
+	e.lower.Attach(e)
+}
+
+// IsAttached implements stack.LinkEndpoint.IsAttached.
+func (e *Endpoint) IsAttached() bool {
+	e.mu.RLock()
+	defer e.mu.RUnlock()
+	return e.dispatcher != nil
+}
+
+// MTU implements stack.LinkEndpoint.MTU. It just forwards the request to the
+// lower endpoint.
+func (e *Endpoint) MTU() uint32 {
+	return e.lower.MTU()
+}
+
+// SetMTU implements stack.LinkEndpoint.SetMTU. It just forwards the request to
+// the lower endpoint.
+func (e *Endpoint) SetMTU(mtu uint32) {
+	e.lower.SetMTU(mtu)
+}
+
+// Capabilities implements stack.LinkEndpoint.Capabilities. It just forwards the
+// request to the lower endpoint.
+func (e *Endpoint) Capabilities() stack.LinkEndpointCapabilities {
+	return e.lower.Capabilities()
+}
+
+// MaxHeaderLength implements stack.LinkEndpoint.MaxHeaderLength. It just
+// forwards the request to the lower endpoint.
+func (e *Endpoint) MaxHeaderLength() uint16 {
+	return e.lower.MaxHeaderLength()
+}
+
+// LinkAddress implements stack.LinkEndpoint.LinkAddress. It just forwards the
+// request to the lower endpoint.
+func (e *Endpoint) LinkAddress() tcpip.LinkAddress {
+	return e.lower.LinkAddress()
+}
+
+// SetLinkAddress implements stack.LinkEndpoint.SetLinkAddress. It forwards the
+// request to the lower endpoint.
+func (e *Endpoint) SetLinkAddress(addr tcpip.LinkAddress) {
+	e.mu.Lock()
+	defer e.mu.Unlock()
+	e.lower.SetLinkAddress(addr)
+}
+
+// WritePackets implements stack.LinkEndpoint.WritePackets. It is called by
+// higher-level protocols to write packets. It only forwards packets to the
+// lower endpoint if Wait or WaitWrite haven't been called.
+func (e *Endpoint) WritePackets(pkts stack.PacketBufferList) (int, tcpip.Error) {
+	if !e.writeGate.Enter() {
+		return pkts.Len(), nil
+	}
+
+	n, err := e.lower.WritePackets(pkts)
+	e.writeGate.Leave()
+	return n, err
+}
+
+// WaitWrite prevents new calls to WritePacket from reaching the lower endpoint,
+// and waits for inflight ones to finish before returning.
+func (e *Endpoint) WaitWrite() {
+	e.writeGate.Close()
+}
+
+// WaitDispatch prevents new calls to DeliverNetworkPacket from reaching the
+// actual dispatcher, and waits for inflight ones to finish before returning.
+func (e *Endpoint) WaitDispatch() {
+	e.dispatchGate.Close()
+}
+
+// Wait implements stack.LinkEndpoint.Wait.
+func (e *Endpoint) Wait() {}
+
+// ARPHardwareType implements stack.LinkEndpoint.ARPHardwareType.
+func (e *Endpoint) ARPHardwareType() header.ARPHardwareType {
+	return e.lower.ARPHardwareType()
+}
+
+// AddHeader implements stack.LinkEndpoint.AddHeader.
+func (e *Endpoint) AddHeader(pkt *stack.PacketBuffer) {
+	e.lower.AddHeader(pkt)
+}
+
+// ParseHeader implements stack.LinkEndpoint.ParseHeader.
+func (e *Endpoint) ParseHeader(pkt *stack.PacketBuffer) bool {
+	return e.lower.ParseHeader(pkt)
+}
+
+// SetOnCloseAction implements stack.LinkEndpoint.SetOnCloseAction.
+func (e *Endpoint) SetOnCloseAction(action func()) {
+	e.lower.SetOnCloseAction(action)
+}
+
+// Close implements stack.LinkEndpoint.
+func (e *Endpoint) Close() {
+	e.lower.Close()
+}