From bbcfbd66002c4aa1b2d8fd7e10a71c930b66da49 Mon Sep 17 00:00:00 2001
From: Sergey Matveev <stargrave@stargrave.org>
Date: Sun, 15 Mar 2015 19:04:20 +0300
Subject: [PATCH] Keep TAP listener state and skip sinkReady step if necessary

Signed-off-by: Sergey Matveev <stargrave@stargrave.org>
---
 tap.go       | 22 ++++++++++++----------
 transport.go | 16 +++++++++++-----
 2 files changed, 23 insertions(+), 15 deletions(-)

diff --git a/tap.go b/tap.go
index 85926d7..4fee83a 100644
--- a/tap.go
+++ b/tap.go
@@ -26,11 +26,12 @@ import (
 )
 
 type TAP struct {
-	Name  string
-	dev   io.ReadWriter
-	buf   []byte
-	sink  chan []byte
-	ready chan struct{}
+	Name   string
+	dev    io.ReadWriter
+	buf    []byte
+	sink   chan []byte
+	ready  chan struct{}
+	synced bool
 }
 
 func NewTAP(ifaceName string) (*TAP, error) {
@@ -40,11 +41,12 @@ func NewTAP(ifaceName string) (*TAP, error) {
 		return nil, err
 	}
 	tap := TAP{
-		Name:  ifaceName,
-		dev:   tapRaw,
-		buf:   make([]byte, maxIfacePktSize),
-		sink:  make(chan []byte),
-		ready: make(chan struct{}),
+		Name:   ifaceName,
+		dev:    tapRaw,
+		buf:    make([]byte, maxIfacePktSize),
+		sink:   make(chan []byte),
+		ready:  make(chan struct{}),
+		synced: false,
 	}
 	go func() {
 		var n int
diff --git a/transport.go b/transport.go
index 8c5e8eb..d72fcc1 100644
--- a/transport.go
+++ b/transport.go
@@ -102,6 +102,7 @@ func TAPListen(ifaceName string) (*TAP, chan []byte, chan struct{}, chan struct{
 	sink := make(chan []byte)
 	sinkReady := make(chan struct{})
 	sinkTerminate := make(chan struct{})
+	sinkSkip := make(chan struct{})
 
 	go func() {
 		heartbeat := time.Tick(heartbeatPeriodGet())
@@ -114,12 +115,10 @@ func TAPListen(ifaceName string) (*TAP, chan []byte, chan struct{}, chan struct{
 			case <-heartbeat:
 				go func() { sink <- make([]byte, 0) }()
 				continue
+			case <-sinkSkip:
 			case <-sinkReady:
-				if exists {
-					exists = false
-					break
-				}
 				tap.ready <- struct{}{}
+				tap.synced = true
 			}
 		HeartbeatCatched:
 			select {
@@ -129,12 +128,19 @@ func TAPListen(ifaceName string) (*TAP, chan []byte, chan struct{}, chan struct{
 			case <-sinkTerminate:
 				break ListenCycle
 			case pkt = <-tap.sink:
+				tap.synced = false
 				sink <- pkt
 			}
 		}
 		close(sink)
+		close(sinkReady)
+		close(sinkTerminate)
 	}()
-	sinkReady <- struct{}{}
+	if exists && tap.synced {
+		sinkSkip <- struct{}{}
+	} else {
+		sinkReady <- struct{}{}
+	}
 	return tap, sink, sinkReady, sinkTerminate, nil
 }
 
-- 
2.48.1