Merge pull request #165 from jingyuanliang/rf2

Don't set --random-fully if it's not supported even if the flag is true

cmd/ip-masq-agent/ip-masq-agent.go

@@ -61,7 +61,7 @@ var (
 
 	noMasqueradeAllReservedRangesFlag = flag.Bool("nomasq-all-reserved-ranges", false, "Whether to disable masquerade for all IPv4 ranges reserved by RFCs.")
 	enableIPv6                        = flag.Bool("enable-ipv6", false, "Whether to enable IPv6.")
-	randomFully                       = flag.Bool("random-fully", true, "Whether to add --random-fully to the masquerade rule.")
+	randomFully                       = flag.Bool("random-fully", true, "Whether to add --random-fully to the masquerade rule, if the system supports it.")
 )
 
 // MasqConfig object
@@ -337,7 +337,7 @@ func (m *MasqDaemon) syncMasqRules() error {
 	}
 
 	// masquerade all other traffic that is not bound for a --dst-type LOCAL destination
-	writeMasqRules(lines, toPorts)
+	writeMasqRules(lines, m.iptables.HasRandomFully(), toPorts)
 
 	writeLine(lines, "COMMIT")
 	m.logVerbose(lines.String(), logParentID).Infof("IPv4 masquerading rules: %q", lines)
@@ -382,7 +382,7 @@ func (m *MasqDaemon) syncMasqRulesIPv6() error {
 	}
 
 	// masquerade all other traffic that is not bound for a --dst-type LOCAL destination
-	writeMasqRules(lines6, toPorts)
+	writeMasqRules(lines6, m.ip6tables.HasRandomFully(), toPorts)
 
 	writeLine(lines6, "COMMIT")
 	m.logVerbose(lines6.String(), logParentID).Infof("IPv6 masquerading rules: %q", lines6)
@@ -429,9 +429,9 @@ func writeNonMasqRule(lines *bytes.Buffer, cidr string) {
 
 const masqRuleComment = `-m comment --comment "ip-masq-agent: outbound traffic is subject to MASQUERADE (must be last in chain)"`
 
-func writeMasqRules(lines *bytes.Buffer, toPorts interval.Intervals) {
+func writeMasqRules(lines *bytes.Buffer, hasRandomFully bool, toPorts interval.Intervals) {
 	args := []string{masqRuleComment, "-j", "MASQUERADE"}
-	if *randomFully {
+	if hasRandomFully && *randomFully {
 		args = append(args, "--random-fully")
 	}
 

cmd/ip-masq-agent/ip-masq-agent_test.go

@@ -33,6 +33,7 @@ import (
 	iptest "k8s.io/kubernetes/pkg/util/iptables/testing"
 )
 
+var hasRandomFully bool
 var wantRandomFully string
 
 // turn off glog logging during tests to avoid clutter in output
@@ -45,22 +46,34 @@ func TestMain(m *testing.M) {
 
 	for _, tc := range []struct {
 		arg  string
+		has  bool
 		want string
 	}{
+		{},
 		{
+			arg: "false",
+		},
+		{
+			arg: "true",
+		},
+		{
+			has:  true,
 			want: randomFully,
 		},
 		{
 			arg: "false",
+			has: true,
 		},
 		{
 			arg:  "true",
+			has:  true,
 			want: randomFully,
 		},
 	} {
 		if tc.arg != "" {
 			flag.Set("random-fully", tc.arg)
 		}
+		hasRandomFully = tc.has
 		wantRandomFully = tc.want
 
 		ec = max(ec, m.Run())
@@ -72,6 +85,7 @@ func TestMain(m *testing.M) {
 func NewFakeMasqDaemon() *MasqDaemon {
 	masqChain = "IP-MASQ-AGENT"
 	iptables := iptest.NewFake()
+	iptables.SetHasRandomFully(hasRandomFully)
 	iptables.Dump = &iptest.IPTablesDump{
 		Tables: []iptest.Table{
 			{
@@ -83,6 +97,7 @@ func NewFakeMasqDaemon() *MasqDaemon {
 		},
 	}
 	ip6tables := iptest.NewIPv6Fake()
+	ip6tables.SetHasRandomFully(hasRandomFully)
 	ip6tables.Dump = &iptest.IPTablesDump{
 		Tables: []iptest.Table{
 			{
@@ -577,7 +592,7 @@ func TestWriteMasqRules(t *testing.T) {
 			}
 
 			lines := bytes.NewBuffer(nil)
-			writeMasqRules(lines, toPorts)
+			writeMasqRules(lines, hasRandomFully, toPorts)
 
 			s := lines.String()
 			if s != tt.want {