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/qdisc/fifo/fifo.go

@@ -0,0 +1,158 @@
+// 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 fifo provides the implementation of FIFO queuing discipline that
+// queues all outbound packets and asynchronously dispatches them to the
+// lower link endpoint in the order that they were queued.
+package fifo
+
+import (
+	"github.com/sagernet/gvisor/pkg/atomicbitops"
+	"github.com/sagernet/gvisor/pkg/sleep"
+	"github.com/sagernet/gvisor/pkg/sync"
+	"github.com/sagernet/gvisor/pkg/tcpip"
+	"github.com/sagernet/gvisor/pkg/tcpip/stack"
+)
+
+var _ stack.QueueingDiscipline = (*discipline)(nil)
+
+const (
+	// BatchSize is the number of packets to write in each syscall. It is 47
+	// because when GVisorGSO is in use then a single 65KB TCP segment can get
+	// split into 46 segments of 1420 bytes and a single 216 byte segment.
+	BatchSize = 47
+
+	qDiscClosed = 1
+)
+
+// discipline represents a QueueingDiscipline which implements a FIFO queue for
+// all outgoing packets. discipline can have 1 or more underlying
+// queueDispatchers. All outgoing packets are consistently hashed to a single
+// underlying queue using the PacketBuffer.Hash if set, otherwise all packets
+// are queued to the first queue to avoid reordering in case of missing hash.
+//
+// +stateify savable
+type discipline struct {
+	wg          sync.WaitGroup `state:"nosave"`
+	dispatchers []queueDispatcher
+
+	closed atomicbitops.Int32
+}
+
+// queueDispatcher is responsible for dispatching all outbound packets in its
+// queue. It will also smartly batch packets when possible and write them
+// through the lower LinkWriter.
+//
+// +stateify savable
+type queueDispatcher struct {
+	lower stack.LinkWriter
+
+	mu queueDispatcherMutex `state:"nosave"`
+	// +checklocks:mu
+	queue packetBufferCircularList
+
+	newPacketWaker sleep.Waker `state:"nosave"`
+	closeWaker     sleep.Waker `state:"nosave"`
+}
+
+// New creates a new fifo queuing discipline with the n queues with maximum
+// capacity of queueLen.
+//
+// +checklocksignore: we don't have to hold locks during initialization.
+func New(lower stack.LinkWriter, n int, queueLen int) stack.QueueingDiscipline {
+	d := &discipline{
+		dispatchers: make([]queueDispatcher, n),
+	}
+	// Create the required dispatchers
+	for i := range d.dispatchers {
+		qd := &d.dispatchers[i]
+		qd.lower = lower
+		qd.queue.init(queueLen)
+
+		d.wg.Add(1)
+		go func() {
+			defer d.wg.Done()
+			qd.dispatchLoop()
+		}()
+	}
+	return d
+}
+
+func (qd *queueDispatcher) dispatchLoop() {
+	s := sleep.Sleeper{}
+	s.AddWaker(&qd.newPacketWaker)
+	s.AddWaker(&qd.closeWaker)
+	defer s.Done()
+
+	var batch stack.PacketBufferList
+	for {
+		switch w := s.Fetch(true); w {
+		case &qd.newPacketWaker:
+		case &qd.closeWaker:
+			qd.mu.Lock()
+			for p := qd.queue.removeFront(); p != nil; p = qd.queue.removeFront() {
+				p.DecRef()
+			}
+			qd.queue.decRef()
+			qd.mu.Unlock()
+			return
+		default:
+			panic("unknown waker")
+		}
+		qd.mu.Lock()
+		for pkt := qd.queue.removeFront(); pkt != nil; pkt = qd.queue.removeFront() {
+			batch.PushBack(pkt)
+			if batch.Len() < BatchSize && !qd.queue.isEmpty() {
+				continue
+			}
+			qd.mu.Unlock()
+			_, _ = qd.lower.WritePackets(batch)
+			batch.Reset()
+			qd.mu.Lock()
+		}
+		qd.mu.Unlock()
+	}
+}
+
+// WritePacket implements stack.QueueingDiscipline.WritePacket.
+//
+// The packet must have the following fields populated:
+//   - pkt.EgressRoute
+//   - pkt.GSOOptions
+//   - pkt.NetworkProtocolNumber
+func (d *discipline) WritePacket(pkt *stack.PacketBuffer) tcpip.Error {
+	if d.closed.Load() == qDiscClosed {
+		return &tcpip.ErrClosedForSend{}
+	}
+	qd := &d.dispatchers[int(pkt.Hash)%len(d.dispatchers)]
+	qd.mu.Lock()
+	haveSpace := qd.queue.hasSpace()
+	if haveSpace {
+		qd.queue.pushBack(pkt.IncRef())
+	}
+	qd.mu.Unlock()
+	if !haveSpace {
+		return &tcpip.ErrNoBufferSpace{}
+	}
+	qd.newPacketWaker.Assert()
+	return nil
+}
+
+func (d *discipline) Close() {
+	d.closed.Store(qDiscClosed)
+	for i := range d.dispatchers {
+		d.dispatchers[i].closeWaker.Assert()
+	}
+	d.wg.Wait()
+}