fix(recv): panic on expired fragment get

gold/link/link.go

@@ -5,7 +5,6 @@ import (
 	"errors"
 	"net"
 	"sync/atomic"
-	"time"
 
 	"github.com/fumiama/WireGold/config"
 	"github.com/fumiama/WireGold/gold/head"
@@ -46,8 +45,8 @@ type Link struct {
 	keys [32]cipher.AEAD
 	// 本机信息
 	me *Me
-	// 最后一次收到报文的时间
-	lastalive *time.Time
+	// 最后一次收到报文的时间 (UnixNano)
+	lastalive atomic.Int64
 	// 是否允许转发
 	allowtrans bool
 	// 是否对数据进行 zstd 压缩

gold/link/nat.go

@@ -2,9 +2,7 @@ package link
 
 import (
 	"encoding/json"
-	"sync/atomic"
 	"time"
-	"unsafe"
 
 	"github.com/sirupsen/logrus"
 
@@ -23,8 +21,8 @@ func (l *Link) keepAlive(dur int64) {
 			if l.me.connections == nil {
 				return
 			}
-			la := (*time.Time)(atomic.LoadPointer((*unsafe.Pointer)(unsafe.Pointer(&l.lastalive))))
-			if la != nil && time.Since(*la) > 10*time.Second*time.Duration(dur) { // 可能已经被阻断， 断开重连
+			la := l.lastalive.Load()
+			if la != 0 && time.Since(time.Unix(0, la)) > 10*time.Second*time.Duration(dur) { // 可能已经被阻断， 断开重连
 				logrus.Warnln(file.Header(), "no response after 10 keep alive tries, re-connecting...")
 				err := l.me.Restart()
 				if err != nil {

gold/link/peer.go

@@ -2,9 +2,7 @@ package link
 
 import (
 	"net"
-	"sync/atomic"
 	"time"
-	"unsafe"
 
 	curve "github.com/fumiama/go-x25519"
 	"github.com/sirupsen/logrus"
@@ -148,7 +146,6 @@ func (m *Me) extractPeer(srcip, dstip net.IP, addr p2p.EndPoint) *Link {
 			p.endpoint = addr
 		}
 	}
-	now := time.Now()
-	atomic.StorePointer((*unsafe.Pointer)(unsafe.Pointer(&p.lastalive)), unsafe.Pointer(&now))
+	p.lastalive.Store(time.Now().UnixNano())
 	return p
 }

gold/link/recv.go

@@ -152,10 +152,18 @@ func (m *Me) wait(data []byte, addr p2p.EndPoint) (h head.PacketBytes) {
 
 	h, got := m.recving.GetOrSet(uint16(seq), header)
 	if got {
-		if h == header {
+		if !h.HasInit() {
+			// GetOrSet found an expired entry: it deleted it and
+			// returned zero-value while reporting got=true, but did
+			// NOT store our header. Re-store it now.
+			m.recving.Set(uint16(seq), header)
+			h = header
+			got = false
+		} else if h == header {
 			panic("unexpected multi-put found")
+		} else {
+			header.ManualDestroy()
 		}
-		header.ManualDestroy()
 	}
 	if config.ShowDebugLog {
 		logrus.Debugln("[recv]", strconv.FormatUint(uint64(seq&0xffff), 16), "get frag part isnew:", !got)