From c6aef93ef141b7eba7d682bf3e52cc82b41b926b Mon Sep 17 00:00:00 2001
From: FUJITA Tomonori <fujita.tomonori@gmail.com>
Date: Sat, 23 Mar 2019 20:48:18 +0900
Subject: fix race of peer deletion

Fixed a race bug that causes the unittest failure. Also fixed
StopBgp() to block until all the peers are deleted cleanly.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
---
 pkg/server/fsm.go | 49 ++++++++++++++++++++++++++-----------------------
 1 file changed, 26 insertions(+), 23 deletions(-)

(limited to 'pkg/server/fsm.go')

diff --git a/pkg/server/fsm.go b/pkg/server/fsm.go
index 6eadfa92..e66054c7 100644
--- a/pkg/server/fsm.go
+++ b/pkg/server/fsm.go
@@ -123,13 +123,13 @@ const (
 
 type fsmMsg struct {
 	MsgType     fsmMsgType
+	fsm         *fsm
 	MsgSrc      string
 	MsgData     interface{}
 	StateReason *fsmStateReason
 	PathList    []*table.Path
 	timestamp   time.Time
 	payload     []byte
-	Version     uint
 }
 
 type fsmOutgoingMsg struct {
@@ -169,13 +169,13 @@ type adminStateOperation struct {
 	Communication []byte
 }
 
-var fsmVersion uint
-
 type fsm struct {
 	gConf                *config.Global
 	pConf                *config.Neighbor
 	lock                 sync.RWMutex
 	state                bgp.FSMState
+	outgoingCh           *channels.InfiniteChannel
+	incomingCh           *channels.InfiniteChannel
 	reason               *fsmStateReason
 	conn                 net.Conn
 	connCh               chan net.Conn
@@ -191,8 +191,8 @@ type fsm struct {
 	policy               *table.RoutingPolicy
 	gracefulRestartTimer *time.Timer
 	twoByteAsTrans       bool
-	version              uint
 	marshallingOptions   *bgp.MarshallingOption
+	notification         chan *bgp.BGPMessage
 }
 
 func (fsm *fsm) bgpMessageStateUpdate(MessageType uint8, isIn bool) {
@@ -267,11 +267,12 @@ func newFSM(gConf *config.Global, pConf *config.Neighbor, policy *table.RoutingP
 	}
 	pConf.State.SessionState = config.IntToSessionStateMap[int(bgp.BGP_FSM_IDLE)]
 	pConf.Timers.State.Downtime = time.Now().Unix()
-	fsmVersion++
 	fsm := &fsm{
 		gConf:                gConf,
 		pConf:                pConf,
 		state:                bgp.BGP_FSM_IDLE,
+		outgoingCh:           channels.NewInfiniteChannel(),
+		incomingCh:           channels.NewInfiniteChannel(),
 		connCh:               make(chan net.Conn, 1),
 		opensentHoldTime:     float64(holdtimeOpensent),
 		adminState:           adminState,
@@ -281,7 +282,7 @@ func newFSM(gConf *config.Global, pConf *config.Neighbor, policy *table.RoutingP
 		peerInfo:             table.NewPeerInfo(gConf, pConf),
 		policy:               policy,
 		gracefulRestartTimer: time.NewTimer(time.Hour),
-		version:              fsmVersion,
+		notification:         make(chan *bgp.BGPMessage, 1),
 	}
 	fsm.gracefulRestartTimer.Stop()
 	return fsm
@@ -382,7 +383,6 @@ type fsmHandler struct {
 	msgCh            *channels.InfiniteChannel
 	stateReasonCh    chan fsmStateReason
 	incoming         *channels.InfiniteChannel
-	stateCh          chan *fsmMsg
 	outgoing         *channels.InfiniteChannel
 	holdTimerResetCh chan bool
 	sentNotification *bgp.BGPMessage
@@ -391,13 +391,12 @@ type fsmHandler struct {
 	wg               *sync.WaitGroup
 }
 
-func newFSMHandler(fsm *fsm, incoming *channels.InfiniteChannel, stateCh chan *fsmMsg, outgoing *channels.InfiniteChannel) *fsmHandler {
+func newFSMHandler(fsm *fsm, outgoing *channels.InfiniteChannel) *fsmHandler {
 	ctx, cancel := context.WithCancel(context.Background())
 	h := &fsmHandler{
 		fsm:              fsm,
 		stateReasonCh:    make(chan fsmStateReason, 2),
-		incoming:         incoming,
-		stateCh:          stateCh,
+		incoming:         fsm.incomingCh,
 		outgoing:         outgoing,
 		holdTimerResetCh: make(chan bool, 2),
 		wg:               &sync.WaitGroup{},
@@ -944,10 +943,10 @@ func (h *fsmHandler) recvMessageWithError() (*fsmMsg, error) {
 			"error": err,
 		}).Warn("Session will be reset due to malformed BGP Header")
 		fmsg := &fsmMsg{
+			fsm:     h.fsm,
 			MsgType: fsmMsgBGPMessage,
 			MsgSrc:  h.fsm.pConf.State.NeighborAddress,
 			MsgData: err,
-			Version: h.fsm.version,
 		}
 		h.fsm.lock.RUnlock()
 		return fmsg, err
@@ -977,10 +976,10 @@ func (h *fsmHandler) recvMessageWithError() (*fsmMsg, error) {
 	}
 	h.fsm.lock.RLock()
 	fmsg := &fsmMsg{
+		fsm:       h.fsm,
 		MsgType:   fsmMsgBGPMessage,
 		MsgSrc:    h.fsm.pConf.State.NeighborAddress,
 		timestamp: now,
-		Version:   h.fsm.version,
 	}
 	h.fsm.lock.RUnlock()
 
@@ -1757,6 +1756,13 @@ func (h *fsmHandler) established(ctx context.Context) (bgp.FSMState, *fsmStateRe
 	for {
 		select {
 		case <-ctx.Done():
+			select {
+			case m := <-fsm.notification:
+				b, _ := m.Serialize(h.fsm.marshallingOptions)
+				h.conn.Write(b)
+			default:
+				// nothing to do
+			}
 			h.conn.Close()
 			return -1, newfsmStateReason(fsmDying, nil, nil)
 		case conn, ok := <-fsm.connCh:
@@ -1881,18 +1887,15 @@ func (h *fsmHandler) loop(ctx context.Context, wg *sync.WaitGroup) error {
 	}
 	fsm.lock.RUnlock()
 
-	// under zero means that the context was canceled.
-	if nextState >= bgp.BGP_FSM_IDLE {
-		fsm.lock.RLock()
-		h.stateCh <- &fsmMsg{
-			MsgType:     fsmMsgStateChange,
-			MsgSrc:      fsm.pConf.State.NeighborAddress,
-			MsgData:     nextState,
-			StateReason: reason,
-			Version:     h.fsm.version,
-		}
-		fsm.lock.RUnlock()
+	fsm.lock.RLock()
+	h.incoming.In() <- &fsmMsg{
+		fsm:         fsm,
+		MsgType:     fsmMsgStateChange,
+		MsgSrc:      fsm.pConf.State.NeighborAddress,
+		MsgData:     nextState,
+		StateReason: reason,
 	}
+	fsm.lock.RUnlock()
 	return nil
 }
 
-- 
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