From 043b7d83bd76c616fa32b815528eec77f2aad5ff Mon Sep 17 00:00:00 2001 From: Ghanan Gowripalan Date: Thu, 30 Apr 2020 10:21:57 -0700 Subject: Prefer temporary addresses Implement rule 7 of Source Address Selection RFC 6724 section 5. This makes temporary (short-lived) addresses preferred over non-temporary addresses when earlier rules are equal. Test: stack_test.TestIPv6SourceAddressSelectionScopeAndSameAddress PiperOrigin-RevId: 309250975 --- pkg/tcpip/stack/nic.go | 7 +++++- pkg/tcpip/stack/stack_test.go | 56 +++++++++++++++++++++++++++++++++++++++---- 2 files changed, 58 insertions(+), 5 deletions(-) (limited to 'pkg/tcpip/stack') diff --git a/pkg/tcpip/stack/nic.go b/pkg/tcpip/stack/nic.go index 25188b4fb..440970a21 100644 --- a/pkg/tcpip/stack/nic.go +++ b/pkg/tcpip/stack/nic.go @@ -452,7 +452,7 @@ type ipv6AddrCandidate struct { // primaryIPv6Endpoint returns an IPv6 endpoint following Source Address // Selection (RFC 6724 section 5). // -// Note, only rules 1-3 are followed. +// Note, only rules 1-3 and 7 are followed. // // remoteAddr must be a valid IPv6 address. func (n *NIC) primaryIPv6Endpoint(remoteAddr tcpip.Address) *referencedNetworkEndpoint { @@ -523,6 +523,11 @@ func (n *NIC) primaryIPv6Endpoint(remoteAddr tcpip.Address) *referencedNetworkEn return sbDep } + // Prefer temporary addresses as per RFC 6724 section 5 rule 7. + if saTemp, sbTemp := sa.ref.configType == slaacTemp, sb.ref.configType == slaacTemp; saTemp != sbTemp { + return saTemp + } + // sa and sb are equal, return the endpoint that is closest to the front of // the primary endpoint list. return i < j diff --git a/pkg/tcpip/stack/stack_test.go b/pkg/tcpip/stack/stack_test.go index c7634ceb1..4a686c891 100644 --- a/pkg/tcpip/stack/stack_test.go +++ b/pkg/tcpip/stack/stack_test.go @@ -2870,14 +2870,25 @@ func TestIPv6SourceAddressSelectionScopeAndSameAddress(t *testing.T) { globalAddr1 = tcpip.Address("\xa0\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01") globalAddr2 = tcpip.Address("\xa0\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02") nicID = 1 + lifetimeSeconds = 9999 ) + prefix1, _, stableGlobalAddr1 := prefixSubnetAddr(0, linkAddr1) + prefix2, _, stableGlobalAddr2 := prefixSubnetAddr(1, linkAddr1) + + var tempIIDHistory [header.IIDSize]byte + header.InitialTempIID(tempIIDHistory[:], nil, nicID) + tempGlobalAddr1 := header.GenerateTempIPv6SLAACAddr(tempIIDHistory[:], stableGlobalAddr1.Address).Address + tempGlobalAddr2 := header.GenerateTempIPv6SLAACAddr(tempIIDHistory[:], stableGlobalAddr2.Address).Address + // Rule 3 is not tested here, and is instead tested by NDP's AutoGenAddr test. tests := []struct { - name string - nicAddrs []tcpip.Address - connectAddr tcpip.Address - expectedLocalAddr tcpip.Address + name string + slaacPrefixForTempAddrBeforeNICAddrAdd tcpip.AddressWithPrefix + nicAddrs []tcpip.Address + slaacPrefixForTempAddrAfterNICAddrAdd tcpip.AddressWithPrefix + connectAddr tcpip.Address + expectedLocalAddr tcpip.Address }{ // Test Rule 1 of RFC 6724 section 5. { @@ -2967,6 +2978,22 @@ func TestIPv6SourceAddressSelectionScopeAndSameAddress(t *testing.T) { expectedLocalAddr: uniqueLocalAddr1, }, + // Test Rule 7 of RFC 6724 section 5. + { + name: "Temp Global most preferred (last address)", + slaacPrefixForTempAddrBeforeNICAddrAdd: prefix1, + nicAddrs: []tcpip.Address{linkLocalAddr1, uniqueLocalAddr1, globalAddr1}, + connectAddr: globalAddr2, + expectedLocalAddr: tempGlobalAddr1, + }, + { + name: "Temp Global most preferred (first address)", + nicAddrs: []tcpip.Address{linkLocalAddr1, uniqueLocalAddr1, globalAddr1}, + slaacPrefixForTempAddrAfterNICAddrAdd: prefix1, + connectAddr: globalAddr2, + expectedLocalAddr: tempGlobalAddr1, + }, + // Test returning the endpoint that is closest to the front when // candidate addresses are "equal" from the perspective of RFC 6724 // section 5. @@ -2988,6 +3015,13 @@ func TestIPv6SourceAddressSelectionScopeAndSameAddress(t *testing.T) { connectAddr: uniqueLocalAddr2, expectedLocalAddr: linkLocalAddr1, }, + { + name: "Temp Global for Global", + slaacPrefixForTempAddrBeforeNICAddrAdd: prefix1, + slaacPrefixForTempAddrAfterNICAddrAdd: prefix2, + connectAddr: globalAddr1, + expectedLocalAddr: tempGlobalAddr2, + }, } for _, test := range tests { @@ -2996,6 +3030,12 @@ func TestIPv6SourceAddressSelectionScopeAndSameAddress(t *testing.T) { s := stack.New(stack.Options{ NetworkProtocols: []stack.NetworkProtocol{ipv6.NewProtocol()}, TransportProtocols: []stack.TransportProtocol{udp.NewProtocol()}, + NDPConfigs: stack.NDPConfigurations{ + HandleRAs: true, + AutoGenGlobalAddresses: true, + AutoGenTempGlobalAddresses: true, + }, + NDPDisp: &ndpDispatcher{}, }) if err := s.CreateNIC(nicID, e); err != nil { t.Fatalf("CreateNIC(%d, _) = %s", nicID, err) @@ -3007,12 +3047,20 @@ func TestIPv6SourceAddressSelectionScopeAndSameAddress(t *testing.T) { }}) s.AddLinkAddress(nicID, llAddr3, linkAddr3) + if test.slaacPrefixForTempAddrBeforeNICAddrAdd != (tcpip.AddressWithPrefix{}) { + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr3, 0, test.slaacPrefixForTempAddrBeforeNICAddrAdd, true, true, lifetimeSeconds, lifetimeSeconds)) + } + for _, a := range test.nicAddrs { if err := s.AddAddress(nicID, ipv6.ProtocolNumber, a); err != nil { t.Errorf("s.AddAddress(%d, %d, %s): %s", nicID, ipv6.ProtocolNumber, a, err) } } + if test.slaacPrefixForTempAddrAfterNICAddrAdd != (tcpip.AddressWithPrefix{}) { + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr3, 0, test.slaacPrefixForTempAddrAfterNICAddrAdd, true, true, lifetimeSeconds, lifetimeSeconds)) + } + if t.Failed() { t.FailNow() } -- cgit v1.2.3