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-rw-r--r--pkg/tcpip/network/ipv6/ndp.go32
-rw-r--r--pkg/tcpip/network/ipv6/ndp_test.go4
-rw-r--r--pkg/tcpip/stack/ndp_test.go111
-rw-r--r--pkg/tcpip/tests/integration/loopback_test.go2
4 files changed, 99 insertions, 50 deletions
diff --git a/pkg/tcpip/network/ipv6/ndp.go b/pkg/tcpip/network/ipv6/ndp.go
index ee36ed254..57d4afd4d 100644
--- a/pkg/tcpip/network/ipv6/ndp.go
+++ b/pkg/tcpip/network/ipv6/ndp.go
@@ -218,7 +218,7 @@ type NDPDispatcher interface {
//
// This function is not permitted to block indefinitely. This function
// is also not permitted to call into the stack.
- OnOffLinkRouteUpdated(tcpip.NICID, tcpip.Subnet, tcpip.Address)
+ OnOffLinkRouteUpdated(tcpip.NICID, tcpip.Subnet, tcpip.Address, header.NDPRoutePreference)
// OnOffLinkRouteInvalidated is called when an off-link route is invalidated.
//
@@ -508,6 +508,8 @@ type ndpState struct {
// defaultRouterState holds data associated with a default router discovered by
// a Router Advertisement (RA).
type defaultRouterState struct {
+ prf header.NDPRoutePreference
+
// Job to invalidate the default router.
//
// Must not be nil.
@@ -726,6 +728,19 @@ func (ndp *ndpState) handleRA(ip tcpip.Address, ra header.NDPRouterAdvert) {
// Is the IPv6 endpoint configured to discover default routers?
if ndp.configs.DiscoverDefaultRouters {
+ prf := ra.DefaultRouterPreference()
+ if prf == header.ReservedRoutePreference {
+ // As per RFC 4191 section 2.2,
+ //
+ // Prf (Default Router Preference)
+ //
+ // If the Reserved (10) value is received, the receiver MUST treat the
+ // value as if it were (00).
+ //
+ // Note that the value 00 is the medium (default) router preference value.
+ prf = header.MediumRoutePreference
+ }
+
rtr, ok := ndp.defaultRouters[ip]
rl := ra.RouterLifetime()
switch {
@@ -735,7 +750,7 @@ func (ndp *ndpState) handleRA(ip tcpip.Address, ra header.NDPRouterAdvert) {
// Only remember it if we currently know about less than
// MaxDiscoveredDefaultRouters routers.
if len(ndp.defaultRouters) < MaxDiscoveredDefaultRouters {
- ndp.rememberDefaultRouter(ip, rl)
+ ndp.rememberDefaultRouter(ip, rl, prf)
}
case ok && rl != 0:
@@ -743,6 +758,14 @@ func (ndp *ndpState) handleRA(ip tcpip.Address, ra header.NDPRouterAdvert) {
// the invalidation job.
rtr.invalidationJob.Cancel()
rtr.invalidationJob.Schedule(rl)
+
+ if prf != rtr.prf {
+ rtr.prf = prf
+
+ // Inform the integrator about router preference updates.
+ ndp.ep.protocol.options.NDPDisp.OnOffLinkRouteUpdated(ndp.ep.nic.ID(), header.IPv6EmptySubnet, ip, prf)
+ }
+
ndp.defaultRouters[ip] = rtr
case ok && rl == 0:
@@ -834,16 +857,17 @@ func (ndp *ndpState) invalidateDefaultRouter(ip tcpip.Address) {
// The router identified by ip MUST NOT already be known by the IPv6 endpoint.
//
// The IPv6 endpoint that ndp belongs to MUST be locked.
-func (ndp *ndpState) rememberDefaultRouter(ip tcpip.Address, rl time.Duration) {
+func (ndp *ndpState) rememberDefaultRouter(ip tcpip.Address, rl time.Duration, prf header.NDPRoutePreference) {
ndpDisp := ndp.ep.protocol.options.NDPDisp
if ndpDisp == nil {
return
}
// Inform the integrator when we discovered a default router.
- ndpDisp.OnOffLinkRouteUpdated(ndp.ep.nic.ID(), header.IPv6EmptySubnet, ip)
+ ndpDisp.OnOffLinkRouteUpdated(ndp.ep.nic.ID(), header.IPv6EmptySubnet, ip, prf)
state := defaultRouterState{
+ prf: prf,
invalidationJob: ndp.ep.protocol.stack.NewJob(&ndp.ep.mu, func() {
ndp.invalidateDefaultRouter(ip)
}),
diff --git a/pkg/tcpip/network/ipv6/ndp_test.go b/pkg/tcpip/network/ipv6/ndp_test.go
index 95d23f200..130438f3b 100644
--- a/pkg/tcpip/network/ipv6/ndp_test.go
+++ b/pkg/tcpip/network/ipv6/ndp_test.go
@@ -42,7 +42,7 @@ type testNDPDispatcher struct {
func (*testNDPDispatcher) OnDuplicateAddressDetectionResult(tcpip.NICID, tcpip.Address, stack.DADResult) {
}
-func (t *testNDPDispatcher) OnOffLinkRouteUpdated(_ tcpip.NICID, _ tcpip.Subnet, addr tcpip.Address) {
+func (t *testNDPDispatcher) OnOffLinkRouteUpdated(_ tcpip.NICID, _ tcpip.Subnet, addr tcpip.Address, _ header.NDPRoutePreference) {
t.addr = addr
}
@@ -93,7 +93,7 @@ func TestStackNDPEndpointInvalidateDefaultRouter(t *testing.T) {
ipv6EP := ep.(*endpoint)
ipv6EP.mu.Lock()
- ipv6EP.mu.ndp.rememberDefaultRouter(lladdr1, time.Hour)
+ ipv6EP.mu.ndp.rememberDefaultRouter(lladdr1, time.Hour, header.MediumRoutePreference)
ipv6EP.mu.Unlock()
if ndpDisp.addr != lladdr1 {
diff --git a/pkg/tcpip/stack/ndp_test.go b/pkg/tcpip/stack/ndp_test.go
index b5c6626d6..1407f497e 100644
--- a/pkg/tcpip/stack/ndp_test.go
+++ b/pkg/tcpip/stack/ndp_test.go
@@ -116,6 +116,7 @@ type ndpOffLinkRouteEvent struct {
nicID tcpip.NICID
subnet tcpip.Subnet
router tcpip.Address
+ prf header.NDPRoutePreference
// true if route was updated, false if invalidated.
updated bool
}
@@ -189,12 +190,13 @@ func (n *ndpDispatcher) OnDuplicateAddressDetectionResult(nicID tcpip.NICID, add
}
// Implements ipv6.NDPDispatcher.OnOffLinkRouteUpdated.
-func (n *ndpDispatcher) OnOffLinkRouteUpdated(nicID tcpip.NICID, subnet tcpip.Subnet, router tcpip.Address) {
+func (n *ndpDispatcher) OnOffLinkRouteUpdated(nicID tcpip.NICID, subnet tcpip.Subnet, router tcpip.Address, prf header.NDPRoutePreference) {
if c := n.offLinkRouteC; c != nil {
c <- ndpOffLinkRouteEvent{
nicID,
subnet,
router,
+ prf,
true,
}
}
@@ -203,10 +205,12 @@ func (n *ndpDispatcher) OnOffLinkRouteUpdated(nicID tcpip.NICID, subnet tcpip.Su
// Implements ipv6.NDPDispatcher.OnOffLinkRouteInvalidated.
func (n *ndpDispatcher) OnOffLinkRouteInvalidated(nicID tcpip.NICID, subnet tcpip.Subnet, router tcpip.Address) {
if c := n.offLinkRouteC; c != nil {
+ var prf header.NDPRoutePreference
c <- ndpOffLinkRouteEvent{
nicID,
subnet,
router,
+ prf,
false,
}
}
@@ -1035,9 +1039,12 @@ func TestSetNDPConfigurations(t *testing.T) {
}
}
-// raBufWithOptsAndDHCPv6 returns a valid NDP Router Advertisement with options
-// and DHCPv6 configurations specified.
-func raBufWithOptsAndDHCPv6(ip tcpip.Address, rl uint16, managedAddress, otherConfigurations bool, optSer header.NDPOptionsSerializer) *stack.PacketBuffer {
+// raBuf returns a valid NDP Router Advertisement with options, router
+// preference and DHCPv6 configurations specified.
+func raBuf(ip tcpip.Address, rl uint16, managedAddress, otherConfigurations bool, prf header.NDPRoutePreference, optSer header.NDPOptionsSerializer) *stack.PacketBuffer {
+ const flagsByte = 1
+ const routerLifetimeOffset = 2
+
icmpSize := header.ICMPv6HeaderSize + header.NDPRAMinimumSize + optSer.Length()
hdr := buffer.NewPrependable(header.IPv6MinimumSize + icmpSize)
pkt := header.ICMPv6(hdr.Prepend(icmpSize))
@@ -1046,19 +1053,19 @@ func raBufWithOptsAndDHCPv6(ip tcpip.Address, rl uint16, managedAddress, otherCo
raPayload := pkt.MessageBody()
ra := header.NDPRouterAdvert(raPayload)
// Populate the Router Lifetime.
- binary.BigEndian.PutUint16(raPayload[2:], rl)
+ binary.BigEndian.PutUint16(raPayload[routerLifetimeOffset:], rl)
// Populate the Managed Address flag field.
if managedAddress {
- // The Managed Addresses flag field is the 7th bit of byte #1 (0-indexing)
- // of the RA payload.
- raPayload[1] |= 1 << 7
+ // The Managed Addresses flag field is the 7th bit of the flags byte.
+ raPayload[flagsByte] |= 1 << 7
}
// Populate the Other Configurations flag field.
if otherConfigurations {
- // The Other Configurations flag field is the 6th bit of byte #1
- // (0-indexing) of the RA payload.
- raPayload[1] |= 1 << 6
+ // The Other Configurations flag field is the 6th bit of the flags byte.
+ raPayload[flagsByte] |= 1 << 6
}
+ // The Prf field is held in the flags byte.
+ raPayload[flagsByte] |= byte(prf) << 3
opts := ra.Options()
opts.Serialize(optSer)
pkt.SetChecksum(header.ICMPv6Checksum(header.ICMPv6ChecksumParams{
@@ -1086,7 +1093,7 @@ func raBufWithOptsAndDHCPv6(ip tcpip.Address, rl uint16, managedAddress, otherCo
// Note, raBufWithOpts does not populate any of the RA fields other than the
// Router Lifetime.
func raBufWithOpts(ip tcpip.Address, rl uint16, optSer header.NDPOptionsSerializer) *stack.PacketBuffer {
- return raBufWithOptsAndDHCPv6(ip, rl, false, false, optSer)
+ return raBuf(ip, rl, false /* managedAddress */, false /* otherConfigurations */, 0 /* prf */, optSer)
}
// raBufWithDHCPv6 returns a valid NDP Router Advertisement with DHCPv6 related
@@ -1094,18 +1101,26 @@ func raBufWithOpts(ip tcpip.Address, rl uint16, optSer header.NDPOptionsSerializ
//
// Note, raBufWithDHCPv6 does not populate any of the RA fields other than the
// DHCPv6 related ones.
-func raBufWithDHCPv6(ip tcpip.Address, managedAddresses, otherConfiguratiosns bool) *stack.PacketBuffer {
- return raBufWithOptsAndDHCPv6(ip, 0, managedAddresses, otherConfiguratiosns, header.NDPOptionsSerializer{})
+func raBufWithDHCPv6(ip tcpip.Address, managedAddresses, otherConfigurations bool) *stack.PacketBuffer {
+ return raBuf(ip, 0, managedAddresses, otherConfigurations, 0 /* prf */, header.NDPOptionsSerializer{})
}
// raBuf returns a valid NDP Router Advertisement.
//
// Note, raBuf does not populate any of the RA fields other than the
// Router Lifetime.
-func raBuf(ip tcpip.Address, rl uint16) *stack.PacketBuffer {
+func raBufSimple(ip tcpip.Address, rl uint16) *stack.PacketBuffer {
return raBufWithOpts(ip, rl, header.NDPOptionsSerializer{})
}
+// raBufWithPrf returns a valid NDP Router Advertisement with a preference.
+//
+// Note, raBufWithPrf does not populate any of the RA fields other than the
+// Router Lifetime and Default Router Preference fields.
+func raBufWithPrf(ip tcpip.Address, rl uint16, prf header.NDPRoutePreference) *stack.PacketBuffer {
+ return raBuf(ip, rl, false /* managedAddress */, false /* otherConfigurations */, prf, header.NDPOptionsSerializer{})
+}
+
// raBufWithPI returns a valid NDP Router Advertisement with a single Prefix
// Information option.
//
@@ -1165,7 +1180,7 @@ func TestDynamicConfigurationsDisabled(t *testing.T) {
config: func(enable bool) ipv6.NDPConfigurations {
return ipv6.NDPConfigurations{DiscoverDefaultRouters: enable}
},
- ra: raBuf(llAddr2, 1000),
+ ra: raBufSimple(llAddr2, 1000),
},
{
name: "No Prefix Discovery",
@@ -1300,10 +1315,8 @@ func boolToUint64(v bool) uint64 {
return 0
}
-// Check e to make sure that the event is for addr on nic with ID 1, and the
-// update flag set to updated.
-func checkOffLinkRouteEvent(e ndpOffLinkRouteEvent, router tcpip.Address, updated bool) string {
- return cmp.Diff(ndpOffLinkRouteEvent{nicID: 1, subnet: header.IPv6EmptySubnet, router: router, updated: updated}, e, cmp.AllowUnexported(e))
+func checkOffLinkRouteEvent(e ndpOffLinkRouteEvent, nicID tcpip.NICID, router tcpip.Address, prf header.NDPRoutePreference, updated bool) string {
+ return cmp.Diff(ndpOffLinkRouteEvent{nicID: nicID, subnet: header.IPv6EmptySubnet, router: router, prf: prf, updated: updated}, e, cmp.AllowUnexported(e))
}
func testWithRAs(t *testing.T, f func(*testing.T, ipv6.HandleRAsConfiguration, bool)) {
@@ -1337,6 +1350,8 @@ func testWithRAs(t *testing.T, f func(*testing.T, ipv6.HandleRAsConfiguration, b
}
func TestRouterDiscovery(t *testing.T) {
+ const nicID = 1
+
testWithRAs(t, func(t *testing.T, handleRAs ipv6.HandleRAsConfiguration, forwarding bool) {
ndpDisp := ndpDispatcher{
offLinkRouteC: make(chan ndpOffLinkRouteEvent, 1),
@@ -1354,12 +1369,12 @@ func TestRouterDiscovery(t *testing.T) {
Clock: clock,
})
- expectOffLinkRouteEvent := func(addr tcpip.Address, updated bool) {
+ expectOffLinkRouteEvent := func(addr tcpip.Address, prf header.NDPRoutePreference, updated bool) {
t.Helper()
select {
case e := <-ndpDisp.offLinkRouteC:
- if diff := checkOffLinkRouteEvent(e, addr, updated); diff != "" {
+ if diff := checkOffLinkRouteEvent(e, nicID, addr, prf, updated); diff != "" {
t.Errorf("off-link route event mismatch (-want +got):\n%s", diff)
}
default:
@@ -1373,7 +1388,8 @@ func TestRouterDiscovery(t *testing.T) {
clock.Advance(timeout)
select {
case e := <-ndpDisp.offLinkRouteC:
- if diff := checkOffLinkRouteEvent(e, addr, false); diff != "" {
+ var prf header.NDPRoutePreference
+ if diff := checkOffLinkRouteEvent(e, nicID, addr, prf, false); diff != "" {
t.Errorf("off-link route event mismatch (-want +got):\n%s", diff)
}
default:
@@ -1385,37 +1401,44 @@ func TestRouterDiscovery(t *testing.T) {
t.Fatalf("SetForwardingDefaultAndAllNICs(%d, %t): %s", ipv6.ProtocolNumber, forwarding, err)
}
- if err := s.CreateNIC(1, e); err != nil {
- t.Fatalf("CreateNIC(1) = %s", err)
+ if err := s.CreateNIC(nicID, e); err != nil {
+ t.Fatalf("CreateNIC(%d, _): %s", nicID, err)
}
// Rx an RA from lladdr2 with zero lifetime. It should not be
// remembered.
- e.InjectInbound(header.IPv6ProtocolNumber, raBuf(llAddr2, 0))
+ e.InjectInbound(header.IPv6ProtocolNumber, raBufSimple(llAddr2, 0))
select {
case <-ndpDisp.offLinkRouteC:
t.Fatal("unexpectedly updated an off-link route with 0 lifetime")
default:
}
- // Rx an RA from lladdr2 with a huge lifetime.
- e.InjectInbound(header.IPv6ProtocolNumber, raBuf(llAddr2, 1000))
- expectOffLinkRouteEvent(llAddr2, true)
+ // Rx an RA from lladdr2 with a huge lifetime and reserved preference value
+ // (which should be interpreted as the default (medium) preference value).
+ e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPrf(llAddr2, 1000, header.ReservedRoutePreference))
+ expectOffLinkRouteEvent(llAddr2, header.MediumRoutePreference, true)
- // Rx an RA from another router (lladdr3) with non-zero lifetime.
+ // Rx an RA from another router (lladdr3) with non-zero lifetime and
+ // non-default preference value.
const l3LifetimeSeconds = 6
- e.InjectInbound(header.IPv6ProtocolNumber, raBuf(llAddr3, l3LifetimeSeconds))
- expectOffLinkRouteEvent(llAddr3, true)
+ e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPrf(llAddr3, l3LifetimeSeconds, header.HighRoutePreference))
+ expectOffLinkRouteEvent(llAddr3, header.HighRoutePreference, true)
- // Rx an RA from lladdr2 with lesser lifetime.
+ // Rx an RA from lladdr2 with lesser lifetime and default (medium)
+ // preference value.
const l2LifetimeSeconds = 2
- e.InjectInbound(header.IPv6ProtocolNumber, raBuf(llAddr2, l2LifetimeSeconds))
+ e.InjectInbound(header.IPv6ProtocolNumber, raBufSimple(llAddr2, l2LifetimeSeconds))
select {
case <-ndpDisp.offLinkRouteC:
t.Fatal("should not receive a off-link route event when updating lifetimes for known routers")
default:
}
+ // Rx an RA from lladdr2 with a different preference.
+ e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPrf(llAddr2, l2LifetimeSeconds, header.LowRoutePreference))
+ expectOffLinkRouteEvent(llAddr2, header.LowRoutePreference, true)
+
// Wait for lladdr2's router invalidation job to execute. The lifetime
// of the router should have been updated to the most recent (smaller)
// lifetime.
@@ -1426,12 +1449,12 @@ func TestRouterDiscovery(t *testing.T) {
expectAsyncOffLinkRouteInvalidationEvent(llAddr2, l2LifetimeSeconds*time.Second)
// Rx an RA from lladdr2 with huge lifetime.
- e.InjectInbound(header.IPv6ProtocolNumber, raBuf(llAddr2, 1000))
- expectOffLinkRouteEvent(llAddr2, true)
+ e.InjectInbound(header.IPv6ProtocolNumber, raBufSimple(llAddr2, 1000))
+ expectOffLinkRouteEvent(llAddr2, header.MediumRoutePreference, true)
// Rx an RA from lladdr2 with zero lifetime. It should be invalidated.
- e.InjectInbound(header.IPv6ProtocolNumber, raBuf(llAddr2, 0))
- expectOffLinkRouteEvent(llAddr2, false)
+ e.InjectInbound(header.IPv6ProtocolNumber, raBufSimple(llAddr2, 0))
+ expectOffLinkRouteEvent(llAddr2, header.MediumRoutePreference, false)
// Wait for lladdr3's router invalidation job to execute. The lifetime
// of the router should have been updated to the most recent (smaller)
@@ -1447,6 +1470,8 @@ func TestRouterDiscovery(t *testing.T) {
// TestRouterDiscoveryMaxRouters tests that only
// ipv6.MaxDiscoveredDefaultRouters discovered routers are remembered.
func TestRouterDiscoveryMaxRouters(t *testing.T) {
+ const nicID = 1
+
ndpDisp := ndpDispatcher{
offLinkRouteC: make(chan ndpOffLinkRouteEvent, 1),
}
@@ -1461,8 +1486,8 @@ func TestRouterDiscoveryMaxRouters(t *testing.T) {
})},
})
- if err := s.CreateNIC(1, e); err != nil {
- t.Fatalf("CreateNIC(1) = %s", err)
+ if err := s.CreateNIC(nicID, e); err != nil {
+ t.Fatalf("CreateNIC(%d, _): %s", nicID, err)
}
// Receive an RA from 2 more than the max number of discovered routers.
@@ -1471,12 +1496,12 @@ func TestRouterDiscoveryMaxRouters(t *testing.T) {
linkAddr[5] = byte(i)
llAddr := header.LinkLocalAddr(tcpip.LinkAddress(linkAddr))
- e.InjectInbound(header.IPv6ProtocolNumber, raBuf(llAddr, 5))
+ e.InjectInbound(header.IPv6ProtocolNumber, raBufSimple(llAddr, 5))
if i <= ipv6.MaxDiscoveredDefaultRouters {
select {
case e := <-ndpDisp.offLinkRouteC:
- if diff := checkOffLinkRouteEvent(e, llAddr, true); diff != "" {
+ if diff := checkOffLinkRouteEvent(e, nicID, llAddr, header.MediumRoutePreference, true); diff != "" {
t.Errorf("off-link route event mismatch (-want +got):\n%s", diff)
}
default:
@@ -4661,7 +4686,7 @@ func TestNoCleanupNDPStateWhenForwardingEnabled(t *testing.T) {
)
select {
case e := <-ndpDisp.offLinkRouteC:
- if diff := checkOffLinkRouteEvent(e, llAddr3, true /* discovered */); diff != "" {
+ if diff := checkOffLinkRouteEvent(e, nicID, llAddr3, header.MediumRoutePreference, true /* discovered */); diff != "" {
t.Errorf("off-link route event mismatch (-want +got):\n%s", diff)
}
default:
diff --git a/pkg/tcpip/tests/integration/loopback_test.go b/pkg/tcpip/tests/integration/loopback_test.go
index b4b2ec723..b2008f0b2 100644
--- a/pkg/tcpip/tests/integration/loopback_test.go
+++ b/pkg/tcpip/tests/integration/loopback_test.go
@@ -44,7 +44,7 @@ type ndpDispatcher struct{}
func (*ndpDispatcher) OnDuplicateAddressDetectionResult(tcpip.NICID, tcpip.Address, stack.DADResult) {
}
-func (*ndpDispatcher) OnOffLinkRouteUpdated(tcpip.NICID, tcpip.Subnet, tcpip.Address) {
+func (*ndpDispatcher) OnOffLinkRouteUpdated(tcpip.NICID, tcpip.Subnet, tcpip.Address, header.NDPRoutePreference) {
}
func (*ndpDispatcher) OnOffLinkRouteInvalidated(tcpip.NICID, tcpip.Subnet, tcpip.Address) {}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-03 13:56:37 +0000