Return only primary addresses in Stack.NICInfo()

Non-primary addresses are used for endpoints created to accept multicast and
broadcast packets, as well as "helper" endpoints (0.0.0.0) that allow sending
packets when no proper address has been assigned yet (e.g., for DHCP). These
addresses are not real addresses from a user point of view and should not be
part of the NICInfo() value. Also see b/127321246 for more info.

This switches NICInfo() to call a new NIC.PrimaryAddresses() function. To still
allow an option to get all addresses (mostly for testing) I added
Stack.GetAllAddresses() and NIC.AllAddresses().

In addition, the return value for GetMainNICAddress() was changed for the case
where the NIC has no primary address. Instead of returning an error here,
it now returns an empty AddressWithPrefix() value. The rational for this
change is that it is a valid case for a NIC to have no primary addresses.

Lastly, I refactored the code based on the new additions.

PiperOrigin-RevId: 270971764

1 files changed, 36 insertions, 28 deletions

diff --git a/pkg/tcpip/stack/stack_test.go b/pkg/tcpip/stack/stack_test.go
index 0c26c9911..7aa10bce9 100644
--- a/pkg/tcpip/stack/stack_test.go
+++ b/pkg/tcpip/stack/stack_test.go
@@ -930,10 +930,10 @@ func TestSpoofingWithAddress(t *testing.T) {
 		t.Fatal("FindRoute failed:", err)
 	}
 	if r.LocalAddress != nonExistentLocalAddr {
-		t.Errorf("Route has wrong local address: got %v, wanted %v", r.LocalAddress, nonExistentLocalAddr)
+		t.Errorf("Route has wrong local address: got %s, want %s", r.LocalAddress, nonExistentLocalAddr)
 	}
 	if r.RemoteAddress != dstAddr {
-		t.Errorf("Route has wrong remote address: got %v, wanted %v", r.RemoteAddress, dstAddr)
+		t.Errorf("Route has wrong remote address: got %s, want %s", r.RemoteAddress, dstAddr)
 	}
 	// Sending a packet works.
 	testSendTo(t, s, dstAddr, ep, nil)
@@ -945,10 +945,10 @@ func TestSpoofingWithAddress(t *testing.T) {
 		t.Fatal("FindRoute failed:", err)
 	}
 	if r.LocalAddress != localAddr {
-		t.Errorf("Route has wrong local address: got %v, wanted %v", r.LocalAddress, nonExistentLocalAddr)
+		t.Errorf("Route has wrong local address: got %s, want %s", r.LocalAddress, nonExistentLocalAddr)
 	}
 	if r.RemoteAddress != dstAddr {
-		t.Errorf("Route has wrong remote address: got %v, wanted %v", r.RemoteAddress, dstAddr)
+		t.Errorf("Route has wrong remote address: got %s, want %s", r.RemoteAddress, dstAddr)
 	}
 	// Sending a packet using the route works.
 	testSend(t, r, ep, nil)
@@ -992,10 +992,10 @@ func TestSpoofingNoAddress(t *testing.T) {
 		t.Fatal("FindRoute failed:", err)
 	}
 	if r.LocalAddress != nonExistentLocalAddr {
-		t.Errorf("Route has wrong local address: got %v, wanted %v", r.LocalAddress, nonExistentLocalAddr)
+		t.Errorf("Route has wrong local address: got %s, want %s", r.LocalAddress, nonExistentLocalAddr)
 	}
 	if r.RemoteAddress != dstAddr {
-		t.Errorf("Route has wrong remote address: got %v, wanted %v", r.RemoteAddress, dstAddr)
+		t.Errorf("Route has wrong remote address: got %s, want %s", r.RemoteAddress, dstAddr)
 	}
 	// Sending a packet works.
 	// FIXME(b/139841518):Spoofing doesn't work if there is no primary address.
@@ -1400,20 +1400,20 @@ func TestGetMainNICAddressAddPrimaryNonPrimary(t *testing.T) {
 							// Check that GetMainNICAddress returns an address if at least
 							// one primary address was added. In that case make sure the
 							// address/prefixLen matches what we added.
+							gotAddr, err := s.GetMainNICAddress(1, fakeNetNumber)
+							if err != nil {
+								t.Fatal("GetMainNICAddress failed:", err)
+							}
 							if len(primaryAddrAdded) == 0 {
-								// No primary addresses present, expect an error.
-								if _, err := s.GetMainNICAddress(1, fakeNetNumber); err != tcpip.ErrNoLinkAddress {
-									t.Fatalf("got s.GetMainNICAddress(...) = %v, wanted = %s", err, tcpip.ErrNoLinkAddress)
+								// No primary addresses present.
+								if wantAddr := (tcpip.AddressWithPrefix{}); gotAddr != wantAddr {
+									t.Fatalf("GetMainNICAddress: got addr = %s, want = %s", gotAddr, wantAddr)
 								}
 							} else {
-								// At least one primary address was added, expect a valid
-								// address and prefixLen.
-								gotAddressWithPefix, err := s.GetMainNICAddress(1, fakeNetNumber)
-								if err != nil {
-									t.Fatal("GetMainNICAddress failed:", err)
-								}
-								if _, ok := primaryAddrAdded[gotAddressWithPefix]; !ok {
-									t.Fatalf("GetMainNICAddress: got addressWithPrefix = %v, wanted any in {%v}", gotAddressWithPefix, primaryAddrAdded)
+								// At least one primary address was added, verify the returned
+								// address is in the list of primary addresses we added.
+								if _, ok := primaryAddrAdded[gotAddr]; !ok {
+									t.Fatalf("GetMainNICAddress: got = %s, want any in {%v}", gotAddr, primaryAddrAdded)
 								}
 							}
 						})
@@ -1452,19 +1452,25 @@ func TestGetMainNICAddressAddRemove(t *testing.T) {
 			}
 
 			// Check that we get the right initial address and prefix length.
-			if gotAddressWithPrefix, err := s.GetMainNICAddress(1, fakeNetNumber); err != nil {
+			gotAddr, err := s.GetMainNICAddress(1, fakeNetNumber)
+			if err != nil {
 				t.Fatal("GetMainNICAddress failed:", err)
-			} else if gotAddressWithPrefix != protocolAddress.AddressWithPrefix {
-				t.Fatalf("got GetMainNICAddress = %+v, want = %+v", gotAddressWithPrefix, protocolAddress.AddressWithPrefix)
+			}
+			if wantAddr := protocolAddress.AddressWithPrefix; gotAddr != wantAddr {
+				t.Fatalf("got s.GetMainNICAddress(...) = %s, want = %s", gotAddr, wantAddr)
 			}
 
 			if err := s.RemoveAddress(1, protocolAddress.AddressWithPrefix.Address); err != nil {
 				t.Fatal("RemoveAddress failed:", err)
 			}
 
-			// Check that we get an error after removal.
-			if _, err := s.GetMainNICAddress(1, fakeNetNumber); err != tcpip.ErrNoLinkAddress {
-				t.Fatalf("got s.GetMainNICAddress(...) = %v, want = %s", err, tcpip.ErrNoLinkAddress)
+			// Check that we get no address after removal.
+			gotAddr, err = s.GetMainNICAddress(1, fakeNetNumber)
+			if err != nil {
+				t.Fatal("GetMainNICAddress failed:", err)
+			}
+			if wantAddr := (tcpip.AddressWithPrefix{}); gotAddr != wantAddr {
+				t.Fatalf("got GetMainNICAddress(...) = %s, want = %s", gotAddr, wantAddr)
 			}
 		})
 	}
@@ -1479,8 +1485,10 @@ func (g *addressGenerator) next(addrLen int) tcpip.Address {
 }
 
 func verifyAddresses(t *testing.T, expectedAddresses, gotAddresses []tcpip.ProtocolAddress) {
+	t.Helper()
+
 	if len(gotAddresses) != len(expectedAddresses) {
-		t.Fatalf("got len(addresses) = %d, wanted = %d", len(gotAddresses), len(expectedAddresses))
+		t.Fatalf("got len(addresses) = %d, want = %d", len(gotAddresses), len(expectedAddresses))
 	}
 
 	sort.Slice(gotAddresses, func(i, j int) bool {
@@ -1519,7 +1527,7 @@ func TestAddAddress(t *testing.T) {
 		})
 	}
 
-	gotAddresses := s.NICInfo()[nicid].ProtocolAddresses
+	gotAddresses := s.AllAddresses()[nicid]
 	verifyAddresses(t, expectedAddresses, gotAddresses)
 }
 
@@ -1551,7 +1559,7 @@ func TestAddProtocolAddress(t *testing.T) {
 		}
 	}
 
-	gotAddresses := s.NICInfo()[nicid].ProtocolAddresses
+	gotAddresses := s.AllAddresses()[nicid]
 	verifyAddresses(t, expectedAddresses, gotAddresses)
 }
 
@@ -1580,7 +1588,7 @@ func TestAddAddressWithOptions(t *testing.T) {
 		}
 	}
 
-	gotAddresses := s.NICInfo()[nicid].ProtocolAddresses
+	gotAddresses := s.AllAddresses()[nicid]
 	verifyAddresses(t, expectedAddresses, gotAddresses)
 }
 
@@ -1615,7 +1623,7 @@ func TestAddProtocolAddressWithOptions(t *testing.T) {
 		}
 	}
 
-	gotAddresses := s.NICInfo()[nicid].ProtocolAddresses
+	gotAddresses := s.AllAddresses()[nicid]
 	verifyAddresses(t, expectedAddresses, gotAddresses)
 }