From 2031cc4701d5bfd21b34d7b0f7dc86920a553385 Mon Sep 17 00:00:00 2001 From: Ghanan Gowripalan Date: Tue, 7 Jan 2020 10:07:59 -0800 Subject: Disable auto-generation of IPv6 link-local addresses for loopback NICs Test: Test that an IPv6 link-local address is not auto-generated for loopback NICs, even when it is enabled for non-loopback NICS. PiperOrigin-RevId: 288519591 --- pkg/tcpip/stack/nic.go | 3 ++- pkg/tcpip/stack/stack.go | 18 +++++++++------- pkg/tcpip/stack/stack_test.go | 49 +++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 61 insertions(+), 9 deletions(-) (limited to 'pkg') diff --git a/pkg/tcpip/stack/nic.go b/pkg/tcpip/stack/nic.go index 044fe5298..523c2a699 100644 --- a/pkg/tcpip/stack/nic.go +++ b/pkg/tcpip/stack/nic.go @@ -174,7 +174,8 @@ func (n *NIC) enable() *tcpip.Error { return err } - if !n.stack.autoGenIPv6LinkLocal { + // Do not auto-generate an IPv6 link-local address for loopback devices. + if !n.stack.autoGenIPv6LinkLocal || n.loopback { return nil } diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go index ffb379363..d4e98f277 100644 --- a/pkg/tcpip/stack/stack.go +++ b/pkg/tcpip/stack/stack.go @@ -444,8 +444,8 @@ type Stack struct { ndpConfigs NDPConfigurations // autoGenIPv6LinkLocal determines whether or not the stack will attempt - // to auto-generate an IPv6 link-local address for newly enabled NICs. - // See the AutoGenIPv6LinkLocal field of Options for more details. + // to auto-generate an IPv6 link-local address for newly enabled non-loopback + // NICs. See the AutoGenIPv6LinkLocal field of Options for more details. autoGenIPv6LinkLocal bool // ndpDisp is the NDP event dispatcher that is used to send the netstack @@ -496,13 +496,15 @@ type Options struct { // before assigning an address to a NIC. NDPConfigs NDPConfigurations - // AutoGenIPv6LinkLocal determins whether or not the stack will attempt - // to auto-generate an IPv6 link-local address for newly enabled NICs. + // AutoGenIPv6LinkLocal determines whether or not the stack will attempt to + // auto-generate an IPv6 link-local address for newly enabled non-loopback + // NICs. + // // Note, setting this to true does not mean that a link-local address - // will be assigned right away, or at all. If Duplicate Address - // Detection is enabled, an address will only be assigned if it - // successfully resolves. If it fails, no further attempt will be made - // to auto-generate an IPv6 link-local address. + // will be assigned right away, or at all. If Duplicate Address Detection + // is enabled, an address will only be assigned if it successfully resolves. + // If it fails, no further attempt will be made to auto-generate an IPv6 + // link-local address. // // The generated link-local address will follow RFC 4291 Appendix A // guidelines. diff --git a/pkg/tcpip/stack/stack_test.go b/pkg/tcpip/stack/stack_test.go index f533949c0..d970a4abb 100644 --- a/pkg/tcpip/stack/stack_test.go +++ b/pkg/tcpip/stack/stack_test.go @@ -2121,6 +2121,55 @@ func TestNICAutoGenAddrWithOpaque(t *testing.T) { } } +// TestNoLinkLocalAutoGenForLoopbackNIC tests that IPv6 link-local addresses are +// not auto-generated for loopback NICs. +func TestNoLinkLocalAutoGenForLoopbackNIC(t *testing.T) { + const nicID = 1 + const nicName = "nicName" + + tests := []struct { + name string + opaqueIIDOpts stack.OpaqueInterfaceIdentifierOptions + }{ + { + name: "IID From MAC", + opaqueIIDOpts: stack.OpaqueInterfaceIdentifierOptions{}, + }, + { + name: "Opaque IID", + opaqueIIDOpts: stack.OpaqueInterfaceIdentifierOptions{ + NICNameFromID: func(_ tcpip.NICID, nicName string) string { + return nicName + }, + }, + }, + } + + for _, test := range tests { + t.Run(test.name, func(t *testing.T) { + opts := stack.Options{ + NetworkProtocols: []stack.NetworkProtocol{ipv6.NewProtocol()}, + AutoGenIPv6LinkLocal: true, + OpaqueIIDOpts: test.opaqueIIDOpts, + } + + e := channel.New(0, 1280, linkAddr1) + s := stack.New(opts) + if err := s.CreateNamedLoopbackNIC(nicID, nicName, e); err != nil { + t.Fatalf("CreateNamedLoopbackNIC(%d, %q, _) = %s", nicID, nicName, err) + } + + addr, err := s.GetMainNICAddress(nicID, header.IPv6ProtocolNumber) + if err != nil { + t.Fatalf("stack.GetMainNICAddress(%d, _) err = %s", nicID, err) + } + if want := (tcpip.AddressWithPrefix{}); addr != want { + t.Errorf("got stack.GetMainNICAddress(%d, _) = %s, want = %s", nicID, addr, want) + } + }) + } +} + // TestNICAutoGenAddrDoesDAD tests that the successful auto-generation of IPv6 // link-local addresses will only be assigned after the DAD process resolves. func TestNICAutoGenAddrDoesDAD(t *testing.T) { -- cgit v1.2.3