From 820c77d5e78787cb7ffb197892d912c9f4c25a22 Mon Sep 17 00:00:00 2001 From: Ghanan Gowripalan Date: Fri, 14 May 2021 16:32:28 -0700 Subject: Validate DAD configs when initializing DAD state Make sure that the initial configurations used by the DAD state is valid. Before this change, an invalid DAD configuration (with a zero-valued retransmit timer) was used so the DAD state would attempt to resolve DAD immediately. This lead to a deadlock in TestDADResolve as when DAD resolves, the stack notifies the NDP dispatcher which would attempt to write to an unbuffered channel while holding a lock. The test goroutine also attempts to obtain a stack.Route (before receiving from the channel) which ends up attempting to take the same lock. Test: stack_test.TestDADResolve PiperOrigin-RevId: 373888540 --- .../internal/ip/duplicate_address_detection.go | 2 ++ pkg/tcpip/stack/ndp_test.go | 21 ++++++++------------- 2 files changed, 10 insertions(+), 13 deletions(-) diff --git a/pkg/tcpip/network/internal/ip/duplicate_address_detection.go b/pkg/tcpip/network/internal/ip/duplicate_address_detection.go index eed49f5d2..5123b7d6a 100644 --- a/pkg/tcpip/network/internal/ip/duplicate_address_detection.go +++ b/pkg/tcpip/network/internal/ip/duplicate_address_detection.go @@ -83,6 +83,8 @@ func (d *DAD) Init(protocolMU sync.Locker, configs stack.DADConfigurations, opts panic(fmt.Sprintf("given a non-zero value for NonceSize (%d) but zero for ExtendDADTransmits", opts.NonceSize)) } + configs.Validate() + *d = DAD{ opts: opts, configs: configs, diff --git a/pkg/tcpip/stack/ndp_test.go b/pkg/tcpip/stack/ndp_test.go index d4ac9e1f8..ac2fa777e 100644 --- a/pkg/tcpip/stack/ndp_test.go +++ b/pkg/tcpip/stack/ndp_test.go @@ -481,13 +481,9 @@ func TestDADResolve(t *testing.T) { } for _, test := range tests { - test := test - t.Run(test.name, func(t *testing.T) { - t.Parallel() - ndpDisp := ndpDispatcher{ - dadC: make(chan ndpDADEvent), + dadC: make(chan ndpDADEvent, 1), } e := channelLinkWithHeaderLength{ @@ -499,7 +495,9 @@ func TestDADResolve(t *testing.T) { var secureRNG bytes.Reader secureRNG.Reset(secureRNGBytes) + clock := faketime.NewManualClock() s := stack.New(stack.Options{ + Clock: clock, SecureRNG: &secureRNG, NetworkProtocols: []stack.NetworkProtocolFactory{ipv6.NewProtocolWithOptions(ipv6.Options{ NDPDisp: &ndpDisp, @@ -529,14 +527,10 @@ func TestDADResolve(t *testing.T) { t.Fatalf("AddAddressWithPrefix(%d, %d, %s) = %s", nicID, header.IPv6ProtocolNumber, addrWithPrefix, err) } - // Address should not be considered bound to the NIC yet (DAD ongoing). - if err := checkGetMainNICAddress(s, nicID, header.IPv6ProtocolNumber, tcpip.AddressWithPrefix{}); err != nil { - t.Fatal(err) - } - // Make sure the address does not resolve before the resolution time has // passed. - time.Sleep(test.expectedRetransmitTimer*time.Duration(test.dupAddrDetectTransmits) - defaultAsyncNegativeEventTimeout) + const delta = time.Nanosecond + clock.Advance(test.expectedRetransmitTimer*time.Duration(test.dupAddrDetectTransmits) - delta) if err := checkGetMainNICAddress(s, nicID, header.IPv6ProtocolNumber, tcpip.AddressWithPrefix{}); err != nil { t.Error(err) } @@ -566,13 +560,14 @@ func TestDADResolve(t *testing.T) { } // Wait for DAD to resolve. + clock.Advance(delta) select { - case <-time.After(defaultAsyncPositiveEventTimeout): - t.Fatal("timed out waiting for DAD resolution") case e := <-ndpDisp.dadC: if diff := checkDADEvent(e, nicID, addr1, &stack.DADSucceeded{}); diff != "" { t.Errorf("DAD event mismatch (-want +got):\n%s", diff) } + default: + t.Fatalf("expected DAD event for %s on NIC(%d)", addr1, nicID) } if err := checkGetMainNICAddress(s, nicID, header.IPv6ProtocolNumber, addrWithPrefix); err != nil { t.Error(err) -- cgit v1.2.3