Join IPv4 all-systems group on NIC enable

Test:
- stack_test.TestJoinLeaveMulticastOnNICEnableDisable
- integration_test.TestIncomingMulticastAndBroadcast
PiperOrigin-RevId: 325185259

3 files changed, 135 insertions, 76 deletions

diff --git a/pkg/tcpip/stack/ndp_test.go b/pkg/tcpip/stack/ndp_test.go
index 644ba7c33..5d286ccbc 100644
--- a/pkg/tcpip/stack/ndp_test.go
+++ b/pkg/tcpip/stack/ndp_test.go
@@ -1689,13 +1689,7 @@ func containsV6Addr(list []tcpip.ProtocolAddress, item tcpip.AddressWithPrefix)
 		AddressWithPrefix: item,
 	}
 
-	for _, i := range list {
-		if i == protocolAddress {
-			return true
-		}
-	}
-
-	return false
+	return containsAddr(list, protocolAddress)
 }
 
 // TestNoAutoGenAddr tests that SLAAC is not performed when configured not to.
diff --git a/pkg/tcpip/stack/nic.go b/pkg/tcpip/stack/nic.go
index ae4d241de..eaaf756cd 100644
--- a/pkg/tcpip/stack/nic.go
+++ b/pkg/tcpip/stack/nic.go
@@ -217,6 +217,11 @@ func (n *NIC) disableLocked() *tcpip.Error {
 	}
 
 	if _, ok := n.stack.networkProtocols[header.IPv4ProtocolNumber]; ok {
+		// The NIC may have already left the multicast group.
+		if err := n.leaveGroupLocked(header.IPv4AllSystems, false /* force */); err != nil && err != tcpip.ErrBadLocalAddress {
+			return err
+		}
+
 		// The address may have already been removed.
 		if err := n.removePermanentAddressLocked(ipv4BroadcastAddr.AddressWithPrefix.Address); err != nil && err != tcpip.ErrBadLocalAddress {
 			return err
@@ -255,6 +260,13 @@ func (n *NIC) enable() *tcpip.Error {
 		if _, err := n.addAddressLocked(ipv4BroadcastAddr, NeverPrimaryEndpoint, permanent, static, false /* deprecated */); err != nil {
 			return err
 		}
+
+		// As per RFC 1122 section 3.3.7, all hosts should join the all-hosts
+		// multicast group. Note, the IANA calls the all-hosts multicast group the
+		// all-systems multicast group.
+		if err := n.joinGroupLocked(header.IPv4ProtocolNumber, header.IPv4AllSystems); err != nil {
+			return err
+		}
 	}
 
 	// Join the IPv6 All-Nodes Multicast group if the stack is configured to
diff --git a/pkg/tcpip/stack/stack_test.go b/pkg/tcpip/stack/stack_test.go
index 63ddbc44e..0b6deda02 100644
--- a/pkg/tcpip/stack/stack_test.go
+++ b/pkg/tcpip/stack/stack_test.go
@@ -277,6 +277,17 @@ func (l *linkEPWithMockedAttach) isAttached() bool {
 	return l.attached
 }
 
+// Checks to see if list contains an address.
+func containsAddr(list []tcpip.ProtocolAddress, item tcpip.ProtocolAddress) bool {
+	for _, i := range list {
+		if i == item {
+			return true
+		}
+	}
+
+	return false
+}
+
 func TestNetworkReceive(t *testing.T) {
 	// Create a stack with the fake network protocol, one nic, and two
 	// addresses attached to it: 1 & 2.
@@ -3089,6 +3100,13 @@ func TestIPv6SourceAddressSelectionScopeAndSameAddress(t *testing.T) {
 
 func TestAddRemoveIPv4BroadcastAddressOnNICEnableDisable(t *testing.T) {
 	const nicID = 1
+	broadcastAddr := tcpip.ProtocolAddress{
+		Protocol: header.IPv4ProtocolNumber,
+		AddressWithPrefix: tcpip.AddressWithPrefix{
+			Address:   header.IPv4Broadcast,
+			PrefixLen: 32,
+		},
+	}
 
 	e := loopback.New()
 	s := stack.New(stack.Options{
@@ -3099,49 +3117,41 @@ func TestAddRemoveIPv4BroadcastAddressOnNICEnableDisable(t *testing.T) {
 		t.Fatalf("CreateNIC(%d, _, %+v) = %s", nicID, nicOpts, err)
 	}
 
-	allStackAddrs := s.AllAddresses()
-	allNICAddrs, ok := allStackAddrs[nicID]
-	if !ok {
-		t.Fatalf("entry for %d missing from allStackAddrs = %+v", nicID, allStackAddrs)
-	}
-	if l := len(allNICAddrs); l != 0 {
-		t.Fatalf("got len(allNICAddrs) = %d, want = 0", l)
+	{
+		allStackAddrs := s.AllAddresses()
+		if allNICAddrs, ok := allStackAddrs[nicID]; !ok {
+			t.Fatalf("entry for %d missing from allStackAddrs = %+v", nicID, allStackAddrs)
+		} else if containsAddr(allNICAddrs, broadcastAddr) {
+			t.Fatalf("got allNICAddrs = %+v, don't want = %+v", allNICAddrs, broadcastAddr)
+		}
 	}
 
 	// Enabling the NIC should add the IPv4 broadcast address.
 	if err := s.EnableNIC(nicID); err != nil {
 		t.Fatalf("s.EnableNIC(%d): %s", nicID, err)
 	}
-	allStackAddrs = s.AllAddresses()
-	allNICAddrs, ok = allStackAddrs[nicID]
-	if !ok {
-		t.Fatalf("entry for %d missing from allStackAddrs = %+v", nicID, allStackAddrs)
-	}
-	if l := len(allNICAddrs); l != 1 {
-		t.Fatalf("got len(allNICAddrs) = %d, want = 1", l)
-	}
-	want := tcpip.ProtocolAddress{
-		Protocol: header.IPv4ProtocolNumber,
-		AddressWithPrefix: tcpip.AddressWithPrefix{
-			Address:   header.IPv4Broadcast,
-			PrefixLen: 32,
-		},
-	}
-	if allNICAddrs[0] != want {
-		t.Fatalf("got allNICAddrs[0] = %+v, want = %+v", allNICAddrs[0], want)
+
+	{
+		allStackAddrs := s.AllAddresses()
+		if allNICAddrs, ok := allStackAddrs[nicID]; !ok {
+			t.Fatalf("entry for %d missing from allStackAddrs = %+v", nicID, allStackAddrs)
+		} else if !containsAddr(allNICAddrs, broadcastAddr) {
+			t.Fatalf("got allNICAddrs = %+v, want = %+v", allNICAddrs, broadcastAddr)
+		}
 	}
 
 	// Disabling the NIC should remove the IPv4 broadcast address.
 	if err := s.DisableNIC(nicID); err != nil {
 		t.Fatalf("s.DisableNIC(%d): %s", nicID, err)
 	}
-	allStackAddrs = s.AllAddresses()
-	allNICAddrs, ok = allStackAddrs[nicID]
-	if !ok {
-		t.Fatalf("entry for %d missing from allStackAddrs = %+v", nicID, allStackAddrs)
-	}
-	if l := len(allNICAddrs); l != 0 {
-		t.Fatalf("got len(allNICAddrs) = %d, want = 0", l)
+
+	{
+		allStackAddrs := s.AllAddresses()
+		if allNICAddrs, ok := allStackAddrs[nicID]; !ok {
+			t.Fatalf("entry for %d missing from allStackAddrs = %+v", nicID, allStackAddrs)
+		} else if containsAddr(allNICAddrs, broadcastAddr) {
+			t.Fatalf("got allNICAddrs = %+v, don't want = %+v", allNICAddrs, broadcastAddr)
+		}
 	}
 }
 
@@ -3189,50 +3199,93 @@ func TestLeaveIPv6SolicitedNodeAddrBeforeAddrRemoval(t *testing.T) {
 	}
 }
 
-func TestJoinLeaveAllNodesMulticastOnNICEnableDisable(t *testing.T) {
+func TestJoinLeaveMulticastOnNICEnableDisable(t *testing.T) {
 	const nicID = 1
 
-	e := loopback.New()
-	s := stack.New(stack.Options{
-		NetworkProtocols: []stack.NetworkProtocol{ipv6.NewProtocol()},
-	})
-	nicOpts := stack.NICOptions{Disabled: true}
-	if err := s.CreateNICWithOptions(nicID, e, nicOpts); err != nil {
-		t.Fatalf("CreateNIC(%d, _, %+v) = %s", nicID, nicOpts, err)
+	tests := []struct {
+		name  string
+		proto tcpip.NetworkProtocolNumber
+		addr  tcpip.Address
+	}{
+		{
+			name:  "IPv6 All-Nodes",
+			proto: header.IPv6ProtocolNumber,
+			addr:  header.IPv6AllNodesMulticastAddress,
+		},
+		{
+			name:  "IPv4 All-Systems",
+			proto: header.IPv4ProtocolNumber,
+			addr:  header.IPv4AllSystems,
+		},
 	}
 
-	// Should not be in the IPv6 all-nodes multicast group yet because the NIC has
-	// not been enabled yet.
-	isInGroup, err := s.IsInGroup(nicID, header.IPv6AllNodesMulticastAddress)
-	if err != nil {
-		t.Fatalf("IsInGroup(%d, %s): %s", nicID, header.IPv6AllNodesMulticastAddress, err)
-	}
-	if isInGroup {
-		t.Fatalf("got IsInGroup(%d, %s) = true, want = false", nicID, header.IPv6AllNodesMulticastAddress)
-	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			e := loopback.New()
+			s := stack.New(stack.Options{
+				NetworkProtocols: []stack.NetworkProtocol{ipv4.NewProtocol(), ipv6.NewProtocol()},
+			})
+			nicOpts := stack.NICOptions{Disabled: true}
+			if err := s.CreateNICWithOptions(nicID, e, nicOpts); err != nil {
+				t.Fatalf("CreateNIC(%d, _, %+v) = %s", nicID, nicOpts, err)
+			}
 
-	// The all-nodes multicast group should be joined when the NIC is enabled.
-	if err := s.EnableNIC(nicID); err != nil {
-		t.Fatalf("s.EnableNIC(%d): %s", nicID, err)
-	}
-	isInGroup, err = s.IsInGroup(nicID, header.IPv6AllNodesMulticastAddress)
-	if err != nil {
-		t.Fatalf("IsInGroup(%d, %s): %s", nicID, header.IPv6AllNodesMulticastAddress, err)
-	}
-	if !isInGroup {
-		t.Fatalf("got IsInGroup(%d, %s) = false, want = true", nicID, header.IPv6AllNodesMulticastAddress)
-	}
+			// Should not be in the multicast group yet because the NIC has not been
+			// enabled yet.
+			if isInGroup, err := s.IsInGroup(nicID, test.addr); err != nil {
+				t.Fatalf("IsInGroup(%d, %s): %s", nicID, test.addr, err)
+			} else if isInGroup {
+				t.Fatalf("got IsInGroup(%d, %s) = true, want = false", nicID, test.addr)
+			}
 
-	// The all-nodes multicast group should be left when the NIC is disabled.
-	if err := s.DisableNIC(nicID); err != nil {
-		t.Fatalf("s.DisableNIC(%d): %s", nicID, err)
-	}
-	isInGroup, err = s.IsInGroup(nicID, header.IPv6AllNodesMulticastAddress)
-	if err != nil {
-		t.Fatalf("IsInGroup(%d, %s): %s", nicID, header.IPv6AllNodesMulticastAddress, err)
-	}
-	if isInGroup {
-		t.Fatalf("got IsInGroup(%d, %s) = true, want = false", nicID, header.IPv6AllNodesMulticastAddress)
+			// The all-nodes multicast group should be joined when the NIC is enabled.
+			if err := s.EnableNIC(nicID); err != nil {
+				t.Fatalf("s.EnableNIC(%d): %s", nicID, err)
+			}
+
+			if isInGroup, err := s.IsInGroup(nicID, test.addr); err != nil {
+				t.Fatalf("IsInGroup(%d, %s): %s", nicID, test.addr, err)
+			} else if !isInGroup {
+				t.Fatalf("got IsInGroup(%d, %s) = false, want = true", nicID, test.addr)
+			}
+
+			// The multicast group should be left when the NIC is disabled.
+			if err := s.DisableNIC(nicID); err != nil {
+				t.Fatalf("s.DisableNIC(%d): %s", nicID, err)
+			}
+
+			if isInGroup, err := s.IsInGroup(nicID, test.addr); err != nil {
+				t.Fatalf("IsInGroup(%d, %s): %s", nicID, test.addr, err)
+			} else if isInGroup {
+				t.Fatalf("got IsInGroup(%d, %s) = true, want = false", nicID, test.addr)
+			}
+
+			// The all-nodes multicast group should be joined when the NIC is enabled.
+			if err := s.EnableNIC(nicID); err != nil {
+				t.Fatalf("s.EnableNIC(%d): %s", nicID, err)
+			}
+
+			if isInGroup, err := s.IsInGroup(nicID, test.addr); err != nil {
+				t.Fatalf("IsInGroup(%d, %s): %s", nicID, test.addr, err)
+			} else if !isInGroup {
+				t.Fatalf("got IsInGroup(%d, %s) = false, want = true", nicID, test.addr)
+			}
+
+			// Leaving the group before disabling the NIC should not cause an error.
+			if err := s.LeaveGroup(test.proto, nicID, test.addr); err != nil {
+				t.Fatalf("s.LeaveGroup(%d, %d, %s): %s", test.proto, nicID, test.addr, err)
+			}
+
+			if err := s.DisableNIC(nicID); err != nil {
+				t.Fatalf("s.DisableNIC(%d): %s", nicID, err)
+			}
+
+			if isInGroup, err := s.IsInGroup(nicID, test.addr); err != nil {
+				t.Fatalf("IsInGroup(%d, %s): %s", nicID, test.addr, err)
+			} else if isInGroup {
+				t.Fatalf("got IsInGroup(%d, %s) = true, want = false", nicID, test.addr)
+			}
+		})
 	}
 }