Pass the NIC-internal name to the NIC name function when generating opaque IIDs

Pass the NIC-internal name to the NIC name function when generating opaque IIDs
so implementations can use the name that was provided when the NIC was created.
Previously, explicit NICID to NIC name resolution was required from the netstack
integrator.

Tests: Test that the name provided when creating a NIC is passed to the NIC name
function when generating opaque IIDs.
PiperOrigin-RevId: 288395359

6 files changed, 72 insertions, 52 deletions

diff --git a/pkg/tcpip/header/ipv6_test.go b/pkg/tcpip/header/ipv6_test.go
index cd1862e42..1994003ed 100644
--- a/pkg/tcpip/header/ipv6_test.go
+++ b/pkg/tcpip/header/ipv6_test.go
@@ -96,7 +96,7 @@ func TestAppendOpaqueInterfaceIdentifier(t *testing.T) {
 			secretKey:  secretKeyBuf[:header.OpaqueIIDSecretKeyMinBytes*2],
 		},
 		{
-			name: "Nil SecretKey",
+			name: "Nil SecretKey and empty nicName",
 			prefix: func() tcpip.Subnet {
 				addrWithPrefix := tcpip.AddressWithPrefix{
 					Address:   "\x01\x02\x03\x05\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
@@ -104,7 +104,7 @@ func TestAppendOpaqueInterfaceIdentifier(t *testing.T) {
 				}
 				return addrWithPrefix.Subnet()
 			}(),
-			nicName:    "eth12",
+			nicName:    "",
 			dadCounter: 3,
 			secretKey:  nil,
 		},
@@ -178,8 +178,8 @@ func TestLinkLocalAddrWithOpaqueIID(t *testing.T) {
 			secretKey:  secretKeyBuf[:header.OpaqueIIDSecretKeyMinBytes*2],
 		},
 		{
-			name:       "Nil SecretKey",
-			nicName:    "eth12",
+			name:       "Nil SecretKey and empty nicName",
+			nicName:    "",
 			dadCounter: 3,
 			secretKey:  nil,
 		},
diff --git a/pkg/tcpip/stack/ndp.go b/pkg/tcpip/stack/ndp.go
index ba6a57e6f..238bc27dc 100644
--- a/pkg/tcpip/stack/ndp.go
+++ b/pkg/tcpip/stack/ndp.go
@@ -1030,7 +1030,7 @@ func (ndp *ndpState) handleAutonomousPrefixInformation(pi header.NDPPrefixInform
 
 	addrBytes := []byte(prefix.ID())
 	if oIID := ndp.nic.stack.opaqueIIDOpts; oIID.NICNameFromID != nil {
-		addrBytes = header.AppendOpaqueInterfaceIdentifier(addrBytes[:header.IIDOffsetInIPv6Address], prefix, oIID.NICNameFromID(ndp.nic.ID()), 0 /* dadCounter */, oIID.SecretKey)
+		addrBytes = header.AppendOpaqueInterfaceIdentifier(addrBytes[:header.IIDOffsetInIPv6Address], prefix, oIID.NICNameFromID(ndp.nic.ID(), ndp.nic.name), 0 /* dadCounter */, oIID.SecretKey)
 	} else {
 		// Only attempt to generate an interface-specific IID if we have a valid
 		// link address.
diff --git a/pkg/tcpip/stack/ndp_test.go b/pkg/tcpip/stack/ndp_test.go
index 8e817e730..9430844d3 100644
--- a/pkg/tcpip/stack/ndp_test.go
+++ b/pkg/tcpip/stack/ndp_test.go
@@ -1918,6 +1918,7 @@ func TestAutoGenAddrWithOpaqueIID(t *testing.T) {
 	t.Parallel()
 
 	const nicID = 1
+	const nicName = "nic1"
 	var secretKeyBuf [header.OpaqueIIDSecretKeyMinBytes]byte
 	secretKey := secretKeyBuf[:]
 	n, err := rand.Read(secretKey)
@@ -1935,12 +1936,12 @@ func TestAutoGenAddrWithOpaqueIID(t *testing.T) {
 	// defined by RFC 7217.
 	addrBytes := []byte(subnet1.ID())
 	addr1 := tcpip.AddressWithPrefix{
-		Address:   tcpip.Address(header.AppendOpaqueInterfaceIdentifier(addrBytes[:header.IIDOffsetInIPv6Address], subnet1, "nic1", 0, secretKey)),
+		Address:   tcpip.Address(header.AppendOpaqueInterfaceIdentifier(addrBytes[:header.IIDOffsetInIPv6Address], subnet1, nicName, 0, secretKey)),
 		PrefixLen: 64,
 	}
 	addrBytes = []byte(subnet2.ID())
 	addr2 := tcpip.AddressWithPrefix{
-		Address:   tcpip.Address(header.AppendOpaqueInterfaceIdentifier(addrBytes[:header.IIDOffsetInIPv6Address], subnet2, "nic1", 0, secretKey)),
+		Address:   tcpip.Address(header.AppendOpaqueInterfaceIdentifier(addrBytes[:header.IIDOffsetInIPv6Address], subnet2, nicName, 0, secretKey)),
 		PrefixLen: 64,
 	}
 
@@ -1956,15 +1957,15 @@ func TestAutoGenAddrWithOpaqueIID(t *testing.T) {
 		},
 		NDPDisp: &ndpDisp,
 		OpaqueIIDOpts: stack.OpaqueInterfaceIdentifierOptions{
-			NICNameFromID: func(nicID tcpip.NICID) string {
-				return fmt.Sprintf("nic%d", nicID)
+			NICNameFromID: func(_ tcpip.NICID, nicName string) string {
+				return nicName
 			},
 			SecretKey: secretKey,
 		},
 	})
 
-	if err := s.CreateNIC(nicID, e); err != nil {
-		t.Fatalf("CreateNIC(%d, _) = %s", nicID, err)
+	if err := s.CreateNamedNIC(nicID, nicName, e); err != nil {
+		t.Fatalf("CreateNamedNIC(%d, %q, _) = %s", nicID, nicName, err)
 	}
 
 	expectAutoGenAddrEvent := func(addr tcpip.AddressWithPrefix, eventType ndpAutoGenAddrEventType) {
diff --git a/pkg/tcpip/stack/nic.go b/pkg/tcpip/stack/nic.go
index 3bed0af3c..044fe5298 100644
--- a/pkg/tcpip/stack/nic.go
+++ b/pkg/tcpip/stack/nic.go
@@ -180,7 +180,7 @@ func (n *NIC) enable() *tcpip.Error {
 
 	var addr tcpip.Address
 	if oIID := n.stack.opaqueIIDOpts; oIID.NICNameFromID != nil {
-		addr = header.LinkLocalAddrWithOpaqueIID(oIID.NICNameFromID(n.ID()), 0, oIID.SecretKey)
+		addr = header.LinkLocalAddrWithOpaqueIID(oIID.NICNameFromID(n.ID(), n.name), 0, oIID.SecretKey)
 	} else {
 		l2addr := n.linkEP.LinkAddress()
 
diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go
index c6e6becf3..ffb379363 100644
--- a/pkg/tcpip/stack/stack.go
+++ b/pkg/tcpip/stack/stack.go
@@ -353,8 +353,13 @@ func (u *uniqueIDGenerator) UniqueID() uint64 {
 }
 
 // NICNameFromID is a function that returns a stable name for the specified NIC,
-// even if the NIC ID changes over time.
-type NICNameFromID func(tcpip.NICID) string
+// even if different NIC IDs are used to refer to the same NIC in different
+// program runs. It is used when generating opaque interface identifiers (IIDs).
+// If the NIC was created with a name, it will be passed to NICNameFromID.
+//
+// NICNameFromID SHOULD return unique NIC names so unique opaque IIDs are
+// generated for the same prefix on differnt NICs.
+type NICNameFromID func(tcpip.NICID, string) string
 
 // OpaqueInterfaceIdentifierOptions holds the options related to the generation
 // of opaque interface indentifiers (IIDs) as defined by RFC 7217.
diff --git a/pkg/tcpip/stack/stack_test.go b/pkg/tcpip/stack/stack_test.go
index e18dfea83..f533949c0 100644
--- a/pkg/tcpip/stack/stack_test.go
+++ b/pkg/tcpip/stack/stack_test.go
@@ -1910,7 +1910,7 @@ func TestNICAutoGenAddr(t *testing.T) {
 			false,
 			linkAddr1,
 			stack.OpaqueInterfaceIdentifierOptions{
-				NICNameFromID: func(nicID tcpip.NICID) string {
+				NICNameFromID: func(nicID tcpip.NICID, _ string) string {
 					return fmt.Sprintf("nic%d", nicID)
 				},
 			},
@@ -2005,6 +2005,8 @@ func TestNICAutoGenAddr(t *testing.T) {
 // always be generated with opaque IIDs if configured to use them, even if the
 // NIC has an invalid MAC address.
 func TestNICAutoGenAddrWithOpaque(t *testing.T) {
+	const nicID = 1
+
 	var secretKey [header.OpaqueIIDSecretKeyMinBytes]byte
 	n, err := rand.Read(secretKey[:])
 	if err != nil {
@@ -2014,54 +2016,61 @@ func TestNICAutoGenAddrWithOpaque(t *testing.T) {
 		t.Fatalf("expected rand.Read to read %d bytes, read %d bytes", header.OpaqueIIDSecretKeyMinBytes, n)
 	}
 
-	iidOpts := stack.OpaqueInterfaceIdentifierOptions{
-		NICNameFromID: func(nicID tcpip.NICID) string {
-			return fmt.Sprintf("nic%d", nicID)
-		},
-		SecretKey: secretKey[:],
-	}
-
 	tests := []struct {
-		name     string
-		autoGen  bool
-		linkAddr tcpip.LinkAddress
+		name      string
+		nicName   string
+		autoGen   bool
+		linkAddr  tcpip.LinkAddress
+		secretKey []byte
 	}{
 		{
-			"Disabled",
-			false,
-			linkAddr1,
+			name:      "Disabled",
+			nicName:   "nic1",
+			autoGen:   false,
+			linkAddr:  linkAddr1,
+			secretKey: secretKey[:],
 		},
 		{
-			"Enabled",
-			true,
-			linkAddr1,
+			name:      "Enabled",
+			nicName:   "nic1",
+			autoGen:   true,
+			linkAddr:  linkAddr1,
+			secretKey: secretKey[:],
 		},
 		// These are all cases where we would not have generated a
 		// link-local address if opaque IIDs were disabled.
 		{
-			"Nil MAC",
-			true,
-			tcpip.LinkAddress([]byte(nil)),
+			name:      "Nil MAC and empty nicName",
+			nicName:   "",
+			autoGen:   true,
+			linkAddr:  tcpip.LinkAddress([]byte(nil)),
+			secretKey: secretKey[:1],
 		},
 		{
-			"Empty MAC",
-			true,
-			tcpip.LinkAddress(""),
+			name:      "Empty MAC and empty nicName",
+			autoGen:   true,
+			linkAddr:  tcpip.LinkAddress(""),
+			secretKey: secretKey[:2],
 		},
 		{
-			"Invalid MAC",
-			true,
-			tcpip.LinkAddress("\x01\x02\x03"),
+			name:      "Invalid MAC",
+			nicName:   "test",
+			autoGen:   true,
+			linkAddr:  tcpip.LinkAddress("\x01\x02\x03"),
+			secretKey: secretKey[:3],
 		},
 		{
-			"Multicast MAC",
-			true,
-			tcpip.LinkAddress("\x01\x02\x03\x04\x05\x06"),
+			name:      "Multicast MAC",
+			nicName:   "test2",
+			autoGen:   true,
+			linkAddr:  tcpip.LinkAddress("\x01\x02\x03\x04\x05\x06"),
+			secretKey: secretKey[:4],
 		},
 		{
-			"Unspecified MAC",
-			true,
-			tcpip.LinkAddress("\x00\x00\x00\x00\x00\x00"),
+			name:     "Unspecified MAC and nil SecretKey",
+			nicName:  "test3",
+			autoGen:  true,
+			linkAddr: tcpip.LinkAddress("\x00\x00\x00\x00\x00\x00"),
 		},
 	}
 
@@ -2069,7 +2078,12 @@ func TestNICAutoGenAddrWithOpaque(t *testing.T) {
 		t.Run(test.name, func(t *testing.T) {
 			opts := stack.Options{
 				NetworkProtocols: []stack.NetworkProtocol{ipv6.NewProtocol()},
-				OpaqueIIDOpts:    iidOpts,
+				OpaqueIIDOpts: stack.OpaqueInterfaceIdentifierOptions{
+					NICNameFromID: func(_ tcpip.NICID, nicName string) string {
+						return nicName
+					},
+					SecretKey: test.secretKey,
+				},
 			}
 
 			if test.autoGen {
@@ -2082,19 +2096,19 @@ func TestNICAutoGenAddrWithOpaque(t *testing.T) {
 
 			e := channel.New(10, 1280, test.linkAddr)
 			s := stack.New(opts)
-			if err := s.CreateNIC(1, e); err != nil {
-				t.Fatalf("CreateNIC(_) = %s", err)
+			if err := s.CreateNamedNIC(nicID, test.nicName, e); err != nil {
+				t.Fatalf("CreateNamedNIC(%d, %q, _) = %s", nicID, test.nicName, err)
 			}
 
-			addr, err := s.GetMainNICAddress(1, header.IPv6ProtocolNumber)
+			addr, err := s.GetMainNICAddress(nicID, header.IPv6ProtocolNumber)
 			if err != nil {
-				t.Fatalf("stack.GetMainNICAddress(_, _) err = %s", err)
+				t.Fatalf("stack.GetMainNICAddress(%d, _) err = %s", nicID, err)
 			}
 
 			if test.autoGen {
 				// Should have auto-generated an address and
 				// resolved immediately (DAD is disabled).
-				if want := (tcpip.AddressWithPrefix{Address: header.LinkLocalAddrWithOpaqueIID("nic1", 0, secretKey[:]), PrefixLen: header.IPv6LinkLocalPrefix.PrefixLen}); addr != want {
+				if want := (tcpip.AddressWithPrefix{Address: header.LinkLocalAddrWithOpaqueIID(test.nicName, 0, test.secretKey), PrefixLen: header.IPv6LinkLocalPrefix.PrefixLen}); addr != want {
 					t.Fatalf("got stack.GetMainNICAddress(_, _) = %s, want = %s", addr, want)
 				}
 			} else {