From 6a1dad0ce21f075f36942feb5fced8258f7ff124 Mon Sep 17 00:00:00 2001
From: Joel May <joel@cloudflare.com>
Date: Thu, 10 Nov 2022 09:09:47 -0800
Subject: [PATCH] ZTC-234: macOS tests

---
 ingress/icmp_darwin.go      |  1 -
 ingress/icmp_darwin_test.go |  8 +++++
 ingress/icmp_linux_test.go  | 13 +++++++
 ingress/icmp_posix_test.go  | 72 +++++++++++++++++++++++++++++++------
 4 files changed, 83 insertions(+), 11 deletions(-)
 create mode 100644 ingress/icmp_linux_test.go

diff --git a/ingress/icmp_darwin.go b/ingress/icmp_darwin.go
index dd03e46b..8f95ee89 100644
--- a/ingress/icmp_darwin.go
+++ b/ingress/icmp_darwin.go
@@ -148,7 +148,6 @@ func (ip *icmpProxy) Request(ctx context.Context, pk *packet.ICMP, responder *pa
 		dstIP:          pk.Dst,
 		originalEchoID: originalEcho.ID,
 	}
-	// TODO: TUN-6744 assign unique flow per (src, echo ID)
 	assignedEchoID, success := ip.echoIDTracker.getOrAssign(echoIDTrackerKey)
 	if !success {
 		err := fmt.Errorf("failed to assign unique echo ID")
diff --git a/ingress/icmp_darwin_test.go b/ingress/icmp_darwin_test.go
index 90b92710..6cfacb9d 100644
--- a/ingress/icmp_darwin_test.go
+++ b/ingress/icmp_darwin_test.go
@@ -8,6 +8,8 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/require"
+
+	"github.com/cloudflare/cloudflared/packet"
 )
 
 func TestSingleEchoIDTracker(t *testing.T) {
@@ -119,3 +121,9 @@ func (eit *echoIDTracker) get(key flow3Tuple) (id uint16, exist bool) {
 	id, exists := eit.mapping[key]
 	return id, exists
 }
+
+func getFunnel(t *testing.T, proxy *icmpProxy, tuple flow3Tuple) (packet.Funnel, bool) {
+	assignedEchoID, success := proxy.echoIDTracker.getOrAssign(tuple)
+	require.True(t, success)
+	return proxy.srcFunnelTracker.Get(echoFunnelID(assignedEchoID))
+}
diff --git a/ingress/icmp_linux_test.go b/ingress/icmp_linux_test.go
new file mode 100644
index 00000000..597b5557
--- /dev/null
+++ b/ingress/icmp_linux_test.go
@@ -0,0 +1,13 @@
+//go:build linux
+
+package ingress
+
+import (
+	"testing"
+
+	"github.com/cloudflare/cloudflared/packet"
+)
+
+func getFunnel(t *testing.T, proxy *icmpProxy, tuple flow3Tuple) (packet.Funnel, bool) {
+	return proxy.srcFunnelTracker.Get(tuple)
+}
diff --git a/ingress/icmp_posix_test.go b/ingress/icmp_posix_test.go
index 2e81a65b..79c6c89a 100644
--- a/ingress/icmp_posix_test.go
+++ b/ingress/icmp_posix_test.go
@@ -52,28 +52,18 @@ func TestFunnelIdleTimeout(t *testing.T) {
 			},
 		},
 	}
-	funnelID := flow3Tuple{
-		srcIP:          pk.Src,
-		dstIP:          pk.Dst,
-		originalEchoID: echoID,
-	}
 	muxer := newMockMuxer(0)
 	responder := packetResponder{
 		datagramMuxer: muxer,
 	}
 	require.NoError(t, proxy.Request(ctx, &pk, &responder))
 	validateEchoFlow(t, <-muxer.cfdToEdge, &pk)
-	funnel1, found := proxy.srcFunnelTracker.Get(funnelID)
-	require.True(t, found)
 
 	// Send second request, should reuse the funnel
 	require.NoError(t, proxy.Request(ctx, &pk, &packetResponder{
 		datagramMuxer: muxer,
 	}))
 	validateEchoFlow(t, <-muxer.cfdToEdge, &pk)
-	funnel2, found := proxy.srcFunnelTracker.Get(funnelID)
-	require.True(t, found)
-	require.Equal(t, funnel1, funnel2)
 
 	time.Sleep(idleTimeout * 2)
 	newMuxer := newMockMuxer(0)
@@ -86,3 +76,65 @@ func TestFunnelIdleTimeout(t *testing.T) {
 	cancel()
 	<-proxyDone
 }
+
+func TestReuseFunnel(t *testing.T) {
+	const (
+		idleTimeout = time.Second
+		echoID      = 42573
+		startSeq    = 8129
+	)
+	logger := zerolog.New(os.Stderr)
+	proxy, err := newICMPProxy(localhostIP, "", &logger, idleTimeout)
+	require.NoError(t, err)
+
+	ctx, cancel := context.WithCancel(context.Background())
+
+	proxyDone := make(chan struct{})
+	go func() {
+		proxy.Serve(ctx)
+		close(proxyDone)
+	}()
+
+	// Send a packet to register the flow
+	pk := packet.ICMP{
+		IP: &packet.IP{
+			Src:      localhostIP,
+			Dst:      localhostIP,
+			Protocol: layers.IPProtocolICMPv4,
+		},
+		Message: &icmp.Message{
+			Type: ipv4.ICMPTypeEcho,
+			Code: 0,
+			Body: &icmp.Echo{
+				ID:   echoID,
+				Seq:  startSeq,
+				Data: []byte(t.Name()),
+			},
+		},
+	}
+	tuple := flow3Tuple{
+		srcIP:          pk.Src,
+		dstIP:          pk.Dst,
+		originalEchoID: echoID,
+	}
+	muxer := newMockMuxer(0)
+	responder := packetResponder{
+		datagramMuxer: muxer,
+	}
+	require.NoError(t, proxy.Request(ctx, &pk, &responder))
+	validateEchoFlow(t, <-muxer.cfdToEdge, &pk)
+	funnel1, found := getFunnel(t, proxy, tuple)
+	require.True(t, found)
+
+	// Send second request, should reuse the funnel
+	require.NoError(t, proxy.Request(ctx, &pk, &packetResponder{
+		datagramMuxer: muxer,
+	}))
+	validateEchoFlow(t, <-muxer.cfdToEdge, &pk)
+	funnel2, found := getFunnel(t, proxy, tuple)
+	require.True(t, found)
+	require.Equal(t, funnel1, funnel2)
+
+	cancel()
+	<-proxyDone
+}