net: add a bit clarified multicast listener tests

Also adds -external flag to allow use of external networks on tests.

R=rsc
CC=golang-dev
https://golang.org/cl/5693043

4 files changed, 120 insertions, 83 deletions

diff --git a/src/pkg/net/dialgoogle_test.go b/src/pkg/net/dialgoogle_test.go
index 81750a3d73..14356da4ce 100644
--- a/src/pkg/net/dialgoogle_test.go
+++ b/src/pkg/net/dialgoogle_test.go
@@ -14,7 +14,7 @@ import (
 )
 
 // If an IPv6 tunnel is running, we can try dialing a real IPv6 address.
-var ipv6 = flag.Bool("ipv6", false, "assume ipv6 tunnel is present")
+var testIPv6 = flag.Bool("ipv6", false, "assume ipv6 tunnel is present")
 
 // fd is already connected to the destination, port 80.
 // Run an HTTP request to fetch the appropriate page.
@@ -130,7 +130,7 @@ func TestDialGoogleIPv6(t *testing.T) {
 		return
 	}
 	// Only run tcp6 if the kernel will take it.
-	if !*ipv6 || !supportsIPv6 {
+	if !*testIPv6 || !supportsIPv6 {
 		return
 	}
 
diff --git a/src/pkg/net/lookup_test.go b/src/pkg/net/lookup_test.go
index 9a39ca8a1e..7b9ea844cd 100644
--- a/src/pkg/net/lookup_test.go
+++ b/src/pkg/net/lookup_test.go
@@ -8,14 +8,14 @@
 package net
 
 import (
-	"runtime"
+	"flag"
 	"testing"
 )
 
-var avoidMacFirewall = runtime.GOOS == "darwin"
+var testExternal = flag.Bool("external", false, "allow use of external networks during test")
 
 func TestGoogleSRV(t *testing.T) {
-	if testing.Short() || avoidMacFirewall {
+	if testing.Short() || !*testExternal {
 		t.Logf("skipping test to avoid external network")
 		return
 	}
@@ -38,7 +38,7 @@ func TestGoogleSRV(t *testing.T) {
 }
 
 func TestGmailMX(t *testing.T) {
-	if testing.Short() || avoidMacFirewall {
+	if testing.Short() || !*testExternal {
 		t.Logf("skipping test to avoid external network")
 		return
 	}
@@ -52,7 +52,7 @@ func TestGmailMX(t *testing.T) {
 }
 
 func TestGmailTXT(t *testing.T) {
-	if testing.Short() || avoidMacFirewall {
+	if testing.Short() || !*testExternal {
 		t.Logf("skipping test to avoid external network")
 		return
 	}
@@ -66,7 +66,7 @@ func TestGmailTXT(t *testing.T) {
 }
 
 func TestGoogleDNSAddr(t *testing.T) {
-	if testing.Short() || avoidMacFirewall {
+	if testing.Short() || !*testExternal {
 		t.Logf("skipping test to avoid external network")
 		return
 	}
diff --git a/src/pkg/net/multicast_test.go b/src/pkg/net/multicast_test.go
index 9727ecdc15..1d760c2105 100644
--- a/src/pkg/net/multicast_test.go
+++ b/src/pkg/net/multicast_test.go
@@ -5,30 +5,46 @@
 package net
 
 import (
+	"errors"
 	"os"
 	"runtime"
+	"syscall"
 	"testing"
 )
 
-var listenMulticastUDPTests = []struct {
+var multicastListenerTests = []struct {
 	net   string
 	gaddr *UDPAddr
 	flags Flags
-	ipv6  bool
+	ipv6  bool // test with underlying AF_INET6 socket
 }{
 	// cf. RFC 4727: Experimental Values in IPv4, IPv6, ICMPv4, ICMPv6, UDP, and TCP Headers
+
 	{"udp", &UDPAddr{IPv4(224, 0, 0, 254), 12345}, FlagUp | FlagLoopback, false},
-	{"udp4", &UDPAddr{IPv4(224, 0, 0, 254), 12345}, FlagUp | FlagLoopback, false},
+	{"udp", &UDPAddr{IPv4(224, 0, 0, 254), 12345}, 0, false},
 	{"udp", &UDPAddr{ParseIP("ff0e::114"), 12345}, FlagUp | FlagLoopback, true},
+	{"udp", &UDPAddr{ParseIP("ff0e::114"), 12345}, 0, true},
+
+	{"udp4", &UDPAddr{IPv4(224, 0, 0, 254), 12345}, FlagUp | FlagLoopback, false},
+	{"udp4", &UDPAddr{IPv4(224, 0, 0, 254), 12345}, 0, false},
+
 	{"udp6", &UDPAddr{ParseIP("ff01::114"), 12345}, FlagUp | FlagLoopback, true},
+	{"udp6", &UDPAddr{ParseIP("ff01::114"), 12345}, 0, true},
 	{"udp6", &UDPAddr{ParseIP("ff02::114"), 12345}, FlagUp | FlagLoopback, true},
+	{"udp6", &UDPAddr{ParseIP("ff02::114"), 12345}, 0, true},
 	{"udp6", &UDPAddr{ParseIP("ff04::114"), 12345}, FlagUp | FlagLoopback, true},
+	{"udp6", &UDPAddr{ParseIP("ff04::114"), 12345}, 0, true},
 	{"udp6", &UDPAddr{ParseIP("ff05::114"), 12345}, FlagUp | FlagLoopback, true},
+	{"udp6", &UDPAddr{ParseIP("ff05::114"), 12345}, 0, true},
 	{"udp6", &UDPAddr{ParseIP("ff08::114"), 12345}, FlagUp | FlagLoopback, true},
+	{"udp6", &UDPAddr{ParseIP("ff08::114"), 12345}, 0, true},
 	{"udp6", &UDPAddr{ParseIP("ff0e::114"), 12345}, FlagUp | FlagLoopback, true},
+	{"udp6", &UDPAddr{ParseIP("ff0e::114"), 12345}, 0, true},
 }
 
-func TestListenMulticastUDP(t *testing.T) {
+// TestMulticastListener tests both single and double listen to a test
+// listener with same address family, same group address and same port.
+func TestMulticastListener(t *testing.T) {
 	switch runtime.GOOS {
 	case "netbsd", "openbsd", "plan9", "windows":
 		return
@@ -38,118 +54,142 @@ func TestListenMulticastUDP(t *testing.T) {
 		}
 	}
 
-	for _, tt := range listenMulticastUDPTests {
+	for _, tt := range multicastListenerTests {
 		if tt.ipv6 && (!supportsIPv6 || os.Getuid() != 0) {
 			continue
 		}
-		ift, err := Interfaces()
+		ifi, err := availMulticastInterface(t, tt.flags)
 		if err != nil {
-			t.Fatalf("Interfaces failed: %v", err)
-		}
-		var ifi *Interface
-		for _, x := range ift {
-			if x.Flags&tt.flags == tt.flags {
-				ifi = &x
-				break
-			}
-		}
-		if ifi == nil {
-			t.Logf("an appropriate multicast interface not found")
-			return
+			continue
 		}
-		c, err := ListenMulticastUDP(tt.net, ifi, tt.gaddr)
+		c1, err := ListenMulticastUDP(tt.net, ifi, tt.gaddr)
 		if err != nil {
-			t.Fatalf("ListenMulticastUDP failed: %v", err)
+			t.Fatalf("First ListenMulticastUDP failed: %v", err)
 		}
-		defer c.Close() // test to listen concurrently across multiple listeners
-		if !tt.ipv6 {
-			testIPv4MulticastSocketOptions(t, c.fd, ifi)
-		} else {
-			testIPv6MulticastSocketOptions(t, c.fd, ifi)
-		}
-		ifmat, err := ifi.MulticastAddrs()
+		checkMulticastListener(t, err, c1, tt.gaddr)
+		c2, err := ListenMulticastUDP(tt.net, ifi, tt.gaddr)
 		if err != nil {
-			t.Fatalf("MulticastAddrs failed: %v", err)
-		}
-		var found bool
-		for _, ifma := range ifmat {
-			if ifma.(*IPAddr).IP.Equal(tt.gaddr.IP) {
-				found = true
-				break
-			}
-		}
-		if !found {
-			t.Fatalf("%q not found in RIB", tt.gaddr.String())
+			t.Fatalf("Second ListenMulticastUDP failed: %v", err)
 		}
-		if c.LocalAddr().String() != tt.gaddr.String() {
-			t.Fatalf("LocalAddr returns %q, expected %q", c.LocalAddr().String(), tt.gaddr.String())
+		checkMulticastListener(t, err, c2, tt.gaddr)
+		c2.Close()
+		switch c1.fd.family {
+		case syscall.AF_INET:
+			testIPv4MulticastSocketOptions(t, c1.fd, ifi)
+		case syscall.AF_INET6:
+			testIPv6MulticastSocketOptions(t, c1.fd, ifi)
 		}
+		c1.Close()
 	}
 }
 
-func TestSimpleListenMulticastUDP(t *testing.T) {
+func TestSimpleMulticastListener(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
 		return
 	}
 
-	for _, tt := range listenMulticastUDPTests {
+	for _, tt := range multicastListenerTests {
 		if tt.ipv6 {
 			continue
 		}
-		tt.flags = FlagUp | FlagMulticast
+		tt.flags = FlagUp | FlagMulticast // for windows testing
+		ifi, err := availMulticastInterface(t, tt.flags)
+		if err != nil {
+			continue
+		}
+		c1, err := ListenMulticastUDP(tt.net, ifi, tt.gaddr)
+		if err != nil {
+			t.Fatalf("First ListenMulticastUDP failed: %v", err)
+		}
+		checkSimpleMulticastListener(t, err, c1, tt.gaddr)
+		c2, err := ListenMulticastUDP(tt.net, ifi, tt.gaddr)
+		if err != nil {
+			t.Fatalf("Second ListenMulticastUDP failed: %v", err)
+		}
+		checkSimpleMulticastListener(t, err, c2, tt.gaddr)
+		c2.Close()
+		c1.Close()
+	}
+}
+
+func checkMulticastListener(t *testing.T, err error, c *UDPConn, gaddr *UDPAddr) {
+	if !multicastRIBContains(t, gaddr.IP) {
+		t.Fatalf("%q not found in RIB", gaddr.String())
+	}
+	if c.LocalAddr().String() != gaddr.String() {
+		t.Fatalf("LocalAddr returns %q, expected %q", c.LocalAddr().String(), gaddr.String())
+	}
+}
+
+func checkSimpleMulticastListener(t *testing.T, err error, c *UDPConn, gaddr *UDPAddr) {
+	if c.LocalAddr().String() != gaddr.String() {
+		t.Fatalf("LocalAddr returns %q, expected %q", c.LocalAddr().String(), gaddr.String())
+	}
+}
+
+func availMulticastInterface(t *testing.T, flags Flags) (*Interface, error) {
+	var ifi *Interface
+	if flags != Flags(0) {
 		ift, err := Interfaces()
 		if err != nil {
 			t.Fatalf("Interfaces failed: %v", err)
 		}
-		var ifi *Interface
 		for _, x := range ift {
-			if x.Flags&tt.flags == tt.flags {
+			if x.Flags&flags == flags {
 				ifi = &x
 				break
 			}
 		}
 		if ifi == nil {
-			t.Logf("an appropriate multicast interface not found")
-			return
+			return nil, errors.New("an appropriate multicast interface not found")
 		}
-		c, err := ListenMulticastUDP(tt.net, ifi, tt.gaddr)
+	}
+	return ifi, nil
+}
+
+func multicastRIBContains(t *testing.T, ip IP) bool {
+	ift, err := Interfaces()
+	if err != nil {
+		t.Fatalf("Interfaces failed: %v", err)
+	}
+	for _, ifi := range ift {
+		ifmat, err := ifi.MulticastAddrs()
 		if err != nil {
-			t.Fatalf("ListenMulticastUDP failed: %v", err)
+			t.Fatalf("MulticastAddrs failed: %v", err)
 		}
-		if c.LocalAddr().String() != tt.gaddr.String() {
-			t.Fatalf("LocalAddr returns %q, expected %q", c.LocalAddr().String(), tt.gaddr.String())
+		for _, ifma := range ifmat {
+			if ifma.(*IPAddr).IP.Equal(ip) {
+				return true
+			}
 		}
-		c.Close()
 	}
+	return false
 }
 
 func testIPv4MulticastSocketOptions(t *testing.T, fd *netFD, ifi *Interface) {
-	ifmc, err := ipv4MulticastInterface(fd)
+	_, err := ipv4MulticastInterface(fd)
 	if err != nil {
 		t.Fatalf("ipv4MulticastInterface failed: %v", err)
 	}
-	t.Logf("IPv4 multicast interface: %v", ifmc)
-	err = setIPv4MulticastInterface(fd, ifi)
-	if err != nil {
-		t.Fatalf("setIPv4MulticastInterface failed: %v", err)
+	if ifi != nil {
+		err = setIPv4MulticastInterface(fd, ifi)
+		if err != nil {
+			t.Fatalf("setIPv4MulticastInterface failed: %v", err)
+		}
 	}
-
-	ttl, err := ipv4MulticastTTL(fd)
+	_, err = ipv4MulticastTTL(fd)
 	if err != nil {
 		t.Fatalf("ipv4MulticastTTL failed: %v", err)
 	}
-	t.Logf("IPv4 multicast TTL: %v", ttl)
 	err = setIPv4MulticastTTL(fd, 1)
 	if err != nil {
 		t.Fatalf("setIPv4MulticastTTL failed: %v", err)
 	}
-
-	loop, err := ipv4MulticastLoopback(fd)
+	_, err = ipv4MulticastLoopback(fd)
 	if err != nil {
 		t.Fatalf("ipv4MulticastLoopback failed: %v", err)
 	}
-	t.Logf("IPv4 multicast loopback: %v", loop)
 	err = setIPv4MulticastLoopback(fd, false)
 	if err != nil {
 		t.Fatalf("setIPv4MulticastLoopback failed: %v", err)
@@ -157,31 +197,28 @@ func testIPv4MulticastSocketOptions(t *testing.T, fd *netFD, ifi *Interface) {
 }
 
 func testIPv6MulticastSocketOptions(t *testing.T, fd *netFD, ifi *Interface) {
-	ifmc, err := ipv6MulticastInterface(fd)
+	_, err := ipv6MulticastInterface(fd)
 	if err != nil {
 		t.Fatalf("ipv6MulticastInterface failed: %v", err)
 	}
-	t.Logf("IPv6 multicast interface: %v", ifmc)
-	err = setIPv6MulticastInterface(fd, ifi)
-	if err != nil {
-		t.Fatalf("setIPv6MulticastInterface failed: %v", err)
+	if ifi != nil {
+		err = setIPv6MulticastInterface(fd, ifi)
+		if err != nil {
+			t.Fatalf("setIPv6MulticastInterface failed: %v", err)
+		}
 	}
-
-	hoplim, err := ipv6MulticastHopLimit(fd)
+	_, err = ipv6MulticastHopLimit(fd)
 	if err != nil {
 		t.Fatalf("ipv6MulticastHopLimit failed: %v", err)
 	}
-	t.Logf("IPv6 multicast hop limit: %v", hoplim)
 	err = setIPv6MulticastHopLimit(fd, 1)
 	if err != nil {
 		t.Fatalf("setIPv6MulticastHopLimit failed: %v", err)
 	}
-
-	loop, err := ipv6MulticastLoopback(fd)
+	_, err = ipv6MulticastLoopback(fd)
 	if err != nil {
 		t.Fatalf("ipv6MulticastLoopback failed: %v", err)
 	}
-	t.Logf("IPv6 multicast loopback: %v", loop)
 	err = setIPv6MulticastLoopback(fd, false)
 	if err != nil {
 		t.Fatalf("setIPv6MulticastLoopback failed: %v", err)
diff --git a/src/pkg/net/server_test.go b/src/pkg/net/server_test.go
index 55691493aa..b986216815 100644
--- a/src/pkg/net/server_test.go
+++ b/src/pkg/net/server_test.go
@@ -95,7 +95,7 @@ func doTest(t *testing.T, network, listenaddr, dialaddr string) {
 	t.Logf("Test %q %q %q", network, listenaddr, dialaddr)
 	switch listenaddr {
 	case "", "0.0.0.0", "[::]", "[::ffff:0.0.0.0]":
-		if testing.Short() || avoidMacFirewall {
+		if testing.Short() || !*testExternal {
 			t.Logf("skip wildcard listen during short test")
 			return
 		}