portallocator: un-export PortAllocator.Begin, PortAllocator.End

These values are configured when instantiating the allocator, and not
intended to be mutated externally. They're only used internally with
the exception of a test in the bridge driver that uses it to pick a
port that can be used for testing.

This patch:

- un-exports the Begin and End fields
- introduces a GetPortRange() utility to allow the bridge driver
  to get the port, but marking it as a function for internal use.

Signed-off-by: Sebastiaan van Stijn <[email protected]>

libnetwork/drivers/bridge/port_mapping_linux_test.go

@@ -413,7 +413,7 @@ func TestAddPortMappings(t *testing.T) {
 	ctrIP4 := newIPNet(t, "172.19.0.2/16")
 	ctrIP4Mapped := newIPNet(t, "::ffff:172.19.0.2/112")
 	ctrIP6 := newIPNet(t, "fdf8:b88e:bb5c:3483::2/64")
-	firstEphemPort := uint16(portallocator.Get().Begin)
+	firstEphemPort, _ := portallocator.GetPortRange()
 
 	testcases := []struct {
 		name         string

libnetwork/portallocator/portallocator.go

@@ -64,8 +64,8 @@ type (
 		mutex     sync.Mutex
 		defaultIP net.IP
 		ipMap     ipMapping
-		Begin     int
-		End       int
+		begin     int
+		end       int
 	}
 	portRange struct {
 		begin int
@@ -80,6 +80,15 @@ type (
 	protoMap map[string]*portMap
 )
 
+// GetPortRange returns the PortAllocator's default port range.
+//
+// This function is for internal use in tests, and must not be used
+// for other purposes.
+func GetPortRange() (start, end uint16) {
+	p := Get()
+	return uint16(p.begin), uint16(p.end)
+}
+
 // Get returns the PortAllocator
 func Get() *PortAllocator {
 	// Port Allocator is a singleton
@@ -98,8 +107,8 @@ func newInstance() *PortAllocator {
 	return &PortAllocator{
 		ipMap:     ipMapping{},
 		defaultIP: net.IPv4zero,
-		Begin:     start,
-		End:       end,
+		begin:     start,
+		end:       end,
 	}
 }
 
@@ -148,9 +157,9 @@ func (p *PortAllocator) RequestPortsInRange(ips []net.IP, proto string, portStar
 		ipstr := ip.String()
 		if _, ok := p.ipMap[ipstr]; !ok {
 			p.ipMap[ipstr] = protoMap{
-				"tcp":  newPortMap(p.Begin, p.End),
-				"udp":  newPortMap(p.Begin, p.End),
-				"sctp": newPortMap(p.Begin, p.End),
+				"tcp":  newPortMap(p.begin, p.end),
+				"udp":  newPortMap(p.begin, p.end),
+				"sctp": newPortMap(p.begin, p.end),
 			}
 		}
 		pMaps[i] = p.ipMap[ipstr][proto]

libnetwork/portallocator/portallocator_test.go

@@ -16,7 +16,7 @@ func TestRequestNewPort(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	if expected := p.Begin; port != expected {
+	if expected := p.begin; port != expected {
 		t.Fatalf("Expected port %d got %d", expected, port)
 	}
 }
@@ -101,13 +101,13 @@ func TestUnknowProtocol(t *testing.T) {
 func TestAllocateAllPorts(t *testing.T) {
 	p := newInstance()
 
-	for i := 0; i <= p.End-p.Begin; i++ {
+	for i := 0; i <= p.end-p.begin; i++ {
 		port, err := p.RequestPort(net.IPv4zero, "tcp", 0)
 		if err != nil {
 			t.Fatal(err)
 		}
 
-		if expected := p.Begin + i; port != expected {
+		if expected := p.begin + i; port != expected {
 			t.Fatalf("Expected port %d got %d", expected, port)
 		}
 	}
@@ -122,7 +122,7 @@ func TestAllocateAllPorts(t *testing.T) {
 	}
 
 	// release a port in the middle and ensure we get another tcp port
-	port := p.Begin + 5
+	port := p.begin + 5
 	p.ReleasePort(net.IPv4zero, "tcp", port)
 	newPort, err := p.RequestPort(net.IPv4zero, "tcp", 0)
 	if err != nil {
@@ -148,13 +148,13 @@ func BenchmarkAllocatePorts(b *testing.B) {
 	p := newInstance()
 
 	for i := 0; i < b.N; i++ {
-		for i := 0; i <= p.End-p.Begin; i++ {
+		for i := 0; i <= p.end-p.begin; i++ {
 			port, err := p.RequestPort(net.IPv4zero, "tcp", 0)
 			if err != nil {
 				b.Fatal(err)
 			}
 
-			if expected := p.Begin + i; port != expected {
+			if expected := p.begin + i; port != expected {
 				b.Fatalf("Expected port %d got %d", expected, port)
 			}
 		}
@@ -289,15 +289,15 @@ func TestPortAllocationWithCustomRange(t *testing.T) {
 func TestNoDuplicateBPR(t *testing.T) {
 	p := newInstance()
 
-	if port, err := p.RequestPort(net.IPv4zero, "tcp", p.Begin); err != nil {
+	if port, err := p.RequestPort(net.IPv4zero, "tcp", p.begin); err != nil {
 		t.Fatal(err)
-	} else if port != p.Begin {
-		t.Fatalf("Expected port %d got %d", p.Begin, port)
+	} else if port != p.begin {
+		t.Fatalf("Expected port %d got %d", p.begin, port)
 	}
 
 	if port, err := p.RequestPort(net.IPv4zero, "tcp", 0); err != nil {
 		t.Fatal(err)
-	} else if port == p.Begin {
+	} else if port == p.begin {
 		t.Fatalf("Acquire(0) allocated the same port twice: %d", port)
 	}
 }
@@ -310,7 +310,7 @@ func TestRequestPortForMultipleIPs(t *testing.T) {
 	// Default port range.
 	port, err := p.RequestPortsInRange(addrs, "tcp", 0, 0)
 	assert.Check(t, err)
-	assert.Check(t, is.Equal(port, p.Begin))
+	assert.Check(t, is.Equal(port, p.begin))
 
 	// Single-port range.
 	port, err = p.RequestPortsInRange(addrs, "tcp", 10000, 10000)