Merge pull request #10238 from miminar/ephemeral-port-range-allocation

Use system's ephemeral port range for port allocation

daemon/networkdriver/portallocator/portallocator.go

@@ -1,10 +1,24 @@
 package portallocator
 
 import (
+	"bufio"
 	"errors"
 	"fmt"
 	"net"
+	"os"
 	"sync"
+
+	log "github.com/Sirupsen/logrus"
+)
+
+const (
+	DefaultPortRangeStart = 49153
+	DefaultPortRangeEnd   = 65535
+)
+
+var (
+	beginPortRange = DefaultPortRangeStart
+	endPortRange   = DefaultPortRangeEnd
 )
 
 type portMap struct {
@@ -15,7 +29,7 @@ type portMap struct {
 func newPortMap() *portMap {
 	return &portMap{
 		p:    map[int]struct{}{},
-		last: EndPortRange,
+		last: endPortRange,
 	}
 }
 
@@ -30,11 +44,6 @@ func newProtoMap() protoMap {
 
 type ipMapping map[string]protoMap
 
-const (
-	BeginPortRange = 49153
-	EndPortRange   = 65535
-)
-
 var (
 	ErrAllPortsAllocated = errors.New("all ports are allocated")
 	ErrUnknownProtocol   = errors.New("unknown protocol")
@@ -59,6 +68,31 @@ func NewErrPortAlreadyAllocated(ip string, port int) ErrPortAlreadyAllocated {
 	}
 }
 
+func init() {
+	const param = "/proc/sys/net/ipv4/ip_local_port_range"
+
+	file, err := os.Open(param)
+	if err != nil {
+		log.Errorf("Failed to read %s kernel parameter: %s", param, err.Error())
+		return
+	}
+	var start, end int
+	n, err := fmt.Fscanf(bufio.NewReader(file), "%d\t%d", &start, &end)
+	if n != 2 || err != nil {
+		if err == nil {
+			err = fmt.Errorf("unexpected count of parsed numbers (%d)", n)
+		}
+		log.Errorf("Failed to parse port range from %s: %v", param, err)
+		return
+	}
+	beginPortRange = start
+	endPortRange = end
+}
+
+func PortRange() (int, int) {
+	return beginPortRange, endPortRange
+}
+
 func (e ErrPortAlreadyAllocated) IP() string {
 	return e.ip
 }
@@ -137,10 +171,10 @@ func ReleaseAll() error {
 
 func (pm *portMap) findPort() (int, error) {
 	port := pm.last
-	for i := 0; i <= EndPortRange-BeginPortRange; i++ {
+	for i := 0; i <= endPortRange-beginPortRange; i++ {
 		port++
-		if port > EndPortRange {
-			port = BeginPortRange
+		if port > endPortRange {
+			port = beginPortRange
 		}
 
 		if _, ok := pm.p[port]; !ok {

daemon/networkdriver/portallocator/portallocator_test.go

@@ -5,6 +5,11 @@ import (
 	"testing"
 )
 
+func init() {
+	beginPortRange = DefaultPortRangeStart
+	endPortRange = DefaultPortRangeEnd
+}
+
 func reset() {
 	ReleaseAll()
 }
@@ -17,7 +22,7 @@ func TestRequestNewPort(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	if expected := BeginPortRange; port != expected {
+	if expected := beginPortRange; port != expected {
 		t.Fatalf("Expected port %d got %d", expected, port)
 	}
 }
@@ -102,13 +107,13 @@ func TestUnknowProtocol(t *testing.T) {
 func TestAllocateAllPorts(t *testing.T) {
 	defer reset()
 
-	for i := 0; i <= EndPortRange-BeginPortRange; i++ {
+	for i := 0; i <= endPortRange-beginPortRange; i++ {
 		port, err := RequestPort(defaultIP, "tcp", 0)
 		if err != nil {
 			t.Fatal(err)
 		}
 
-		if expected := BeginPortRange + i; port != expected {
+		if expected := beginPortRange + i; port != expected {
 			t.Fatalf("Expected port %d got %d", expected, port)
 		}
 	}
@@ -123,7 +128,7 @@ func TestAllocateAllPorts(t *testing.T) {
 	}
 
 	// release a port in the middle and ensure we get another tcp port
-	port := BeginPortRange + 5
+	port := beginPortRange + 5
 	if err := ReleasePort(defaultIP, "tcp", port); err != nil {
 		t.Fatal(err)
 	}
@@ -153,13 +158,13 @@ func BenchmarkAllocatePorts(b *testing.B) {
 	defer reset()
 
 	for i := 0; i < b.N; i++ {
-		for i := 0; i <= EndPortRange-BeginPortRange; i++ {
+		for i := 0; i <= endPortRange-beginPortRange; i++ {
 			port, err := RequestPort(defaultIP, "tcp", 0)
 			if err != nil {
 				b.Fatal(err)
 			}
 
-			if expected := BeginPortRange + i; port != expected {
+			if expected := beginPortRange + i; port != expected {
 				b.Fatalf("Expected port %d got %d", expected, port)
 			}
 		}
@@ -231,15 +236,15 @@ func TestPortAllocation(t *testing.T) {
 func TestNoDuplicateBPR(t *testing.T) {
 	defer reset()
 
-	if port, err := RequestPort(defaultIP, "tcp", BeginPortRange); err != nil {
+	if port, err := RequestPort(defaultIP, "tcp", beginPortRange); err != nil {
 		t.Fatal(err)
-	} else if port != BeginPortRange {
-		t.Fatalf("Expected port %d got %d", BeginPortRange, port)
+	} else if port != beginPortRange {
+		t.Fatalf("Expected port %d got %d", beginPortRange, port)
 	}
 
 	if port, err := RequestPort(defaultIP, "tcp", 0); err != nil {
 		t.Fatal(err)
-	} else if port == BeginPortRange {
+	} else if port == beginPortRange {
 		t.Fatalf("Acquire(0) allocated the same port twice: %d", port)
 	}
 }

daemon/networkdriver/portmapper/mapper_test.go

@@ -129,7 +129,8 @@ func TestMapAllPortsSingleInterface(t *testing.T) {
 	}()
 
 	for i := 0; i < 10; i++ {
-		for i := portallocator.BeginPortRange; i < portallocator.EndPortRange; i++ {
+		start, end := portallocator.PortRange()
+		for i := start; i < end; i++ {
 			if host, err = Map(srcAddr1, dstIp1, 0); err != nil {
 				t.Fatal(err)
 			}
@@ -137,8 +138,8 @@ func TestMapAllPortsSingleInterface(t *testing.T) {
 			hosts = append(hosts, host)
 		}
 
-		if _, err := Map(srcAddr1, dstIp1, portallocator.BeginPortRange); err == nil {
-			t.Fatalf("Port %d should be bound but is not", portallocator.BeginPortRange)
+		if _, err := Map(srcAddr1, dstIp1, start); err == nil {
+			t.Fatalf("Port %d should be bound but is not", start)
 		}
 
 		for _, val := range hosts {