fix: 完成 broker 复审 B-03 至 B-12

每连接异步下发与背压、写出后断开、校验当前连接与订阅、生命周期串行、登录条件更新、闲置按在线计、认证超时并发与 Shutdown 0x8B。

cmd/nixmsg/serve.go

@@ -153,7 +153,7 @@ func runServe(ctx context.Context, cfg config.Config) error {
 		Sessions:           sessionTokens,
 		MaxScheduleSeconds: int64(cfg.Limits.MaxScheduleSeconds),
 		Logger:             slog.Default(),
-		ConnControl:        brk,
+		ConnControl:        nil, // B-04：踢线走 Session 钩子，避免 identity 20ms 异步 Disconnect
 		Downlink:           brk,
 		ClientIP: func(r *http.Request) string {
 			return httpx.ClientIP(r, trustedNets)
@@ -310,6 +310,10 @@ func runServe(ctx context.Context, cfg config.Config) error {
 
 	<-ctx.Done()
 	loopCancel()
+	// B-08：先对 MQTT 连接发 0x8B。HTTP Shutdown 与监听器完整停机顺序见 L-03。
+	shutCtx, shutCancel := context.WithTimeout(context.Background(), 5*time.Second)
+	_ = brk.Shutdown(shutCtx)
+	shutCancel()
 	_ = lnSrv.Close()
 	drainCtx, drainCancel := context.WithTimeout(context.Background(), 10*time.Second)
 	defer drainCancel()

cmd/nixmsg/uplink.go

@@ -5,12 +5,14 @@ import (
 	"encoding/json"
 	"errors"
 	"log/slog"
+	"sync"
 
 	"git.asio.asia/nixevol/NixMsg/internal/app/group"
 	"git.asio.asia/nixevol/NixMsg/internal/app/identity"
 	"git.asio.asia/nixevol/NixMsg/internal/app/message"
 	"git.asio.asia/nixevol/NixMsg/internal/app/port"
 	"git.asio.asia/nixevol/NixMsg/internal/app/presence"
+	"git.asio.asia/nixevol/NixMsg/internal/broker"
 	"git.asio.asia/nixevol/NixMsg/internal/metrics"
 	"git.asio.asia/nixevol/NixMsg/internal/protocol"
 )
@@ -25,9 +27,31 @@ type appUplink struct {
 	down     port.Downlink
 	log      *slog.Logger
 	metrics  *metrics.Registry
+
+	lifeMu    sync.Mutex
+	lifeLocks map[string]*sync.Mutex
+	hsMu      sync.Mutex
+	handshake map[port.ConnID]string // 已 hello 的连接代号 → 端编号
+}
+
+func (u *appUplink) epLife(endpointID string) *sync.Mutex {
+	u.lifeMu.Lock()
+	defer u.lifeMu.Unlock()
+	if u.lifeLocks == nil {
+		u.lifeLocks = make(map[string]*sync.Mutex)
+	}
+	m := u.lifeLocks[endpointID]
+	if m == nil {
+		m = &sync.Mutex{}
+		u.lifeLocks[endpointID] = m
+	}
+	return m
 }
 
 func (u *appUplink) OnSessionEstablished(ctx context.Context, conn port.ConnInfo) error {
+	lk := u.epLife(conn.EndpointID)
+	lk.Lock()
+	defer lk.Unlock()
 	u.conns.Set(conn.EndpointID, message.LiveConn{
 		ConnID:        conn.ConnID,
 		MaxPacketSize: conn.MaxPacketSize,
@@ -36,6 +60,15 @@ func (u *appUplink) OnSessionEstablished(ctx context.Context, conn port.ConnInfo
 }
 
 func (u *appUplink) OnHandshakeComplete(ctx context.Context, hs port.HandshakeInfo) error {
+	lk := u.epLife(hs.EndpointID)
+	lk.Lock()
+	defer lk.Unlock()
+	u.hsMu.Lock()
+	if u.handshake == nil {
+		u.handshake = make(map[port.ConnID]string)
+	}
+	u.handshake[hs.ConnID] = hs.EndpointID
+	u.hsMu.Unlock()
 	live := message.LiveConn{
 		ConnID:          hs.ConnID,
 		MaxReceiveBytes: hs.MaxReceiveBytes,
@@ -50,11 +83,18 @@ func (u *appUplink) OnHandshakeComplete(ctx context.Context, hs port.HandshakeIn
 }
 
 func (u *appUplink) OnDisconnect(ctx context.Context, conn port.ConnInfo, reason port.DisconnectReason) {
+	lk := u.epLife(conn.EndpointID)
+	lk.Lock()
+	defer lk.Unlock()
 	if u.presence != nil {
 		u.presence.ClearWatch(conn.ConnID)
 	}
+	u.hsMu.Lock()
+	_, handshook := u.handshake[conn.ConnID]
+	delete(u.handshake, conn.ConnID)
+	u.hsMu.Unlock()
 	live, ok := u.conns.Current(conn.EndpointID)
-	isCurrent := ok && live.ConnID == conn.ConnID
+	isCurrent := ok && live.ConnID == conn.ConnID && handshook
 	if err := u.msg.OnDisconnect(ctx, conn.EndpointID, conn.ConnID, isCurrent); err != nil {
 		u.log.Error("message disconnect", "endpoint", conn.EndpointID, "err", err)
 	}
@@ -280,7 +320,7 @@ func (u *appUplink) publishResp(ctx context.Context, conn port.ConnInfo, resp pr
 		return
 	}
 	if live, ok := u.conns.Current(conn.EndpointID); ok && live.ConnID == conn.ConnID {
-		limit := respPayloadLimit(live.MaxPacketSize, live.MaxReceiveBytes)
+		limit := broker.EffectivePayloadLimit(live.MaxPacketSize, live.MaxReceiveBytes)
 		if limit > 0 && len(b) > limit {
 			tooLarge := protocol.Resp{
 				V:     protocol.Version,
@@ -300,20 +340,6 @@ func (u *appUplink) publishResp(ctx context.Context, conn port.ConnInfo, resp pr
 	}
 }
 
-func respPayloadLimit(maxPacketSize uint32, maxRecvBytes int) int {
-	limit := 0
-	if maxRecvBytes > 0 {
-		limit = maxRecvBytes
-	}
-	if maxPacketSize > 0 {
-		n := int(maxPacketSize)
-		if limit == 0 || n < limit {
-			limit = n
-		}
-	}
-	return limit
-}
-
 func peekRID(payload []byte) string {
 	var peek struct {
 		RID string `json:"rid"`