diff options
| -rw-r--r-- | pkg/tcpip/header/ipv6.go | 4 | ||||
| -rw-r--r-- | pkg/tcpip/stack/ndp.go | 166 | ||||
| -rw-r--r-- | pkg/tcpip/stack/ndp_test.go | 426 | ||||
| -rw-r--r-- | pkg/tcpip/tcpip.go | 7 |
4 files changed, 586 insertions, 17 deletions
diff --git a/pkg/tcpip/header/ipv6.go b/pkg/tcpip/header/ipv6.go index f1e60911b..0caa51c1e 100644 --- a/pkg/tcpip/header/ipv6.go +++ b/pkg/tcpip/header/ipv6.go @@ -92,7 +92,9 @@ const ( IPv6Any tcpip.Address = "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" ) -// IPv6EmptySubnet is the empty IPv6 subnet. +// IPv6EmptySubnet is the empty IPv6 subnet. It may also be known as the +// catch-all or wildcard subnet. That is, all IPv6 addresses are considered to +// be contained within this subnet. var IPv6EmptySubnet = func() tcpip.Subnet { subnet, err := tcpip.NewSubnet(IPv6Any, tcpip.AddressMask(IPv6Any)) if err != nil { diff --git a/pkg/tcpip/stack/ndp.go b/pkg/tcpip/stack/ndp.go index d5352bb5f..a216242d8 100644 --- a/pkg/tcpip/stack/ndp.go +++ b/pkg/tcpip/stack/ndp.go @@ -67,6 +67,9 @@ const ( // default routers. The stack should stop discovering new routers after // discovering MaxDiscoveredDefaultRouters routers. // + // This value MUST be at minimum 2 as per RFC 4861 section 6.3.4, and + // SHOULD be more. + // // Max = 10. MaxDiscoveredDefaultRouters = 10 ) @@ -85,6 +88,24 @@ type NDPDispatcher interface { // This function is permitted to block indefinitely without interfering // with the stack's operation. OnDuplicateAddressDetectionStatus(nicid tcpip.NICID, addr tcpip.Address, resolved bool, err *tcpip.Error) + + // OnDefaultRouterDiscovered will be called when a new default router is + // discovered. Implementations must return true along with a new valid + // route table if the newly discovered router should be remembered. If + // an implementation returns false, the second return value will be + // ignored. + // + // This function is not permitted to block indefinitely. This function + // is also not permitted to call into the stack. + OnDefaultRouterDiscovered(nicid tcpip.NICID, addr tcpip.Address) (bool, []tcpip.Route) + + // OnDefaultRouterInvalidated will be called when a discovered default + // router is invalidated. Implementers must return a new valid route + // table. + // + // This function is not permitted to block indefinitely. This function + // is also not permitted to call into the stack. + OnDefaultRouterInvalidated(nicid tcpip.NICID, addr tcpip.Address) []tcpip.Route } // NDPConfigurations is the NDP configurations for the netstack. @@ -165,6 +186,22 @@ type dadState struct { // a Router Advertisement. type defaultRouterState struct { invalidationTimer *time.Timer + + // Used to signal the timer not to invalidate the default router (R) in + // a race condition (T1 is a goroutine that handles an RA from R and T2 + // is the goroutine that handles R's invalidation timer firing): + // T1: Receive a new RA from R + // T1: Obtain the NIC's lock before processing the RA + // T2: R's invalidation timer fires, and gets blocked on obtaining the + // NIC's lock + // T1: Refreshes/extends R's lifetime & releases NIC's lock + // T2: Obtains NIC's lock & invalidates R immediately + // + // To resolve this, T1 will check to see if the timer already fired, and + // signal the timer using this channel to not invalidate R, so that once + // T2 obtains the lock, it will see that there is an event on this + // channel and do nothing further. + doNotInvalidateC chan struct{} } // startDuplicateAddressDetection performs Duplicate Address Detection. @@ -361,16 +398,137 @@ func (ndp *ndpState) stopDuplicateAddressDetection(addr tcpip.Address) { } // handleRA handles a Router Advertisement message that arrived on the NIC -// this ndp is for. +// this ndp is for. Does nothing if the NIC is configured to not handle RAs. // -// The NIC that ndp belongs to MUST be locked. +// The NIC that ndp belongs to and its associated stack MUST be locked. func (ndp *ndpState) handleRA(ip tcpip.Address, ra header.NDPRouterAdvert) { // Is the NIC configured to handle RAs at all? - if !ndp.configs.HandleRAs { + // + // Currently, the stack does not determine router interface status on a + // per-interface basis; it is a stack-wide configuration, so we check + // stack's forwarding flag to determine if the NIC is a routing + // interface. + if !ndp.configs.HandleRAs || ndp.nic.stack.forwarding { return } - // TODO(b/140882146): Do Router Discovery. + // Is the NIC configured to discover default routers? + if ndp.configs.DiscoverDefaultRouters { + rtr, ok := ndp.defaultRouters[ip] + rl := ra.RouterLifetime() + switch { + case !ok && rl != 0: + // This is a new default router we are discovering. + // + // Only remember it if we currently know about less than + // MaxDiscoveredDefaultRouters routers. + if len(ndp.defaultRouters) < MaxDiscoveredDefaultRouters { + ndp.rememberDefaultRouter(ip, rl) + } + + case ok && rl != 0: + // This is an already discovered default router. Update + // the invalidation timer. + timer := rtr.invalidationTimer + + // We should ALWAYS have an invalidation timer for a + // discovered router. + if timer == nil { + panic("ndphandlera: RA invalidation timer should not be nil") + } + + if !timer.Stop() { + // If we reach this point, then we know the + // timer fired after we already took the NIC + // lock. Signal the timer so that once it + // obtains the lock, it doesn't actually + // invalidate the router as we just got a new + // RA that refreshes its lifetime to a non-zero + // value. See + // defaultRouterState.doNotInvalidateC for more + // details. + rtr.doNotInvalidateC <- struct{}{} + } + + timer.Reset(rl) + + case ok && rl == 0: + // We know about the router but it is no longer to be + // used as a default router so invalidate it. + ndp.invalidateDefaultRouter(ip) + } + } + // TODO(b/140948104): Do Prefix Discovery. // TODO(b/141556115): Do Parameter Discovery. } + +// invalidateDefaultRouter invalidates a discovered default router. +// +// The NIC that ndp belongs to and its associated stack MUST be locked. +func (ndp *ndpState) invalidateDefaultRouter(ip tcpip.Address) { + rtr, ok := ndp.defaultRouters[ip] + + // Is the router still discovered? + if !ok { + // ...Nope, do nothing further. + return + } + + rtr.invalidationTimer.Stop() + rtr.invalidationTimer = nil + close(rtr.doNotInvalidateC) + rtr.doNotInvalidateC = nil + + delete(ndp.defaultRouters, ip) + + // Let the integrator know a discovered default router is invalidated. + if ndp.nic.stack.ndpDisp != nil { + ndp.nic.stack.routeTable = ndp.nic.stack.ndpDisp.OnDefaultRouterInvalidated(ndp.nic.ID(), ip) + } +} + +// rememberDefaultRouter remembers a newly discovered default router with IPv6 +// link-local address ip with lifetime rl. +// +// The router identified by ip MUST NOT already be known by the NIC. +// +// The NIC that ndp belongs to and its associated stack MUST be locked. +func (ndp *ndpState) rememberDefaultRouter(ip tcpip.Address, rl time.Duration) { + if ndp.nic.stack.ndpDisp == nil { + return + } + + // Inform the integrator when we discovered a default router. + remember, routeTable := ndp.nic.stack.ndpDisp.OnDefaultRouterDiscovered(ndp.nic.ID(), ip) + if !remember { + // Informed by the integrator to not remember the router, do + // nothing further. + return + } + + // Used to signal the timer not to invalidate the default router (R) in + // a race condition. See defaultRouterState.doNotInvalidateC for more + // details. + doNotInvalidateC := make(chan struct{}, 1) + + ndp.defaultRouters[ip] = defaultRouterState{ + invalidationTimer: time.AfterFunc(rl, func() { + ndp.nic.stack.mu.Lock() + defer ndp.nic.stack.mu.Unlock() + ndp.nic.mu.Lock() + defer ndp.nic.mu.Unlock() + + select { + case <-doNotInvalidateC: + return + default: + } + + ndp.invalidateDefaultRouter(ip) + }), + doNotInvalidateC: doNotInvalidateC, + } + + ndp.nic.stack.routeTable = routeTable +} diff --git a/pkg/tcpip/stack/ndp_test.go b/pkg/tcpip/stack/ndp_test.go index cc789b5af..0dbe4da9d 100644 --- a/pkg/tcpip/stack/ndp_test.go +++ b/pkg/tcpip/stack/ndp_test.go @@ -15,9 +15,12 @@ package stack_test import ( + "encoding/binary" + "fmt" "testing" "time" + "github.com/google/go-cmp/cmp" "gvisor.dev/gvisor/pkg/tcpip" "gvisor.dev/gvisor/pkg/tcpip/buffer" "gvisor.dev/gvisor/pkg/tcpip/checker" @@ -29,10 +32,19 @@ import ( ) const ( - addr1 = "\x0a\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01" - addr2 = "\x0a\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02" - addr3 = "\x0a\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x03" - linkAddr1 = "\x02\x02\x03\x04\x05\x06" + addr1 = "\x0a\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01" + addr2 = "\x0a\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02" + addr3 = "\x0a\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x03" + linkAddr1 = "\x02\x02\x03\x04\x05\x06" + linkAddr2 = "\x02\x02\x03\x04\x05\x07" + linkAddr3 = "\x02\x02\x03\x04\x05\x08" + defaultTimeout = 250 * time.Millisecond +) + +var ( + llAddr1 = header.LinkLocalAddr(linkAddr1) + llAddr2 = header.LinkLocalAddr(linkAddr2) + llAddr3 = header.LinkLocalAddr(linkAddr3) ) // TestDADDisabled tests that an address successfully resolves immediately @@ -77,26 +89,86 @@ type ndpDADEvent struct { err *tcpip.Error } +type ndpRouterEvent struct { + nicid tcpip.NICID + addr tcpip.Address + // true if router was discovered, false if invalidated. + discovered bool +} + var _ stack.NDPDispatcher = (*ndpDispatcher)(nil) // ndpDispatcher implements NDPDispatcher so tests can know when various NDP // related events happen for test purposes. type ndpDispatcher struct { - dadC chan ndpDADEvent + dadC chan ndpDADEvent + routerC chan ndpRouterEvent + rememberRouter bool + routeTable []tcpip.Route } // Implements stack.NDPDispatcher.OnDuplicateAddressDetectionStatus. -// -// If the DAD event matches what we are expecting, send signal on n.dadC. func (n *ndpDispatcher) OnDuplicateAddressDetectionStatus(nicid tcpip.NICID, addr tcpip.Address, resolved bool, err *tcpip.Error) { - n.dadC <- ndpDADEvent{ - nicid, - addr, - resolved, - err, + if n.dadC != nil { + n.dadC <- ndpDADEvent{ + nicid, + addr, + resolved, + err, + } } } +// Implements stack.NDPDispatcher.OnDefaultRouterDiscovered. +func (n *ndpDispatcher) OnDefaultRouterDiscovered(nicid tcpip.NICID, addr tcpip.Address) (bool, []tcpip.Route) { + if n.routerC != nil { + n.routerC <- ndpRouterEvent{ + nicid, + addr, + true, + } + } + + if !n.rememberRouter { + return false, nil + } + + rt := append([]tcpip.Route(nil), n.routeTable...) + rt = append(rt, tcpip.Route{ + Destination: header.IPv6EmptySubnet, + Gateway: addr, + NIC: nicid, + }) + n.routeTable = rt + return true, rt +} + +// Implements stack.NDPDispatcher.OnDefaultRouterInvalidated. +func (n *ndpDispatcher) OnDefaultRouterInvalidated(nicid tcpip.NICID, addr tcpip.Address) []tcpip.Route { + if n.routerC != nil { + n.routerC <- ndpRouterEvent{ + nicid, + addr, + false, + } + } + + var rt []tcpip.Route + exclude := tcpip.Route{ + Destination: header.IPv6EmptySubnet, + Gateway: addr, + NIC: nicid, + } + + for _, r := range n.routeTable { + if r != exclude { + rt = append(rt, r) + } + } + n.routeTable = rt + return rt +} + // TestDADResolve tests that an address successfully resolves after performing // DAD for various values of DupAddrDetectTransmits and RetransmitTimer. // Included in the subtests is a test to make sure that an invalid @@ -609,3 +681,333 @@ func TestSetNDPConfigurations(t *testing.T) { }) } } + +// 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) tcpip.PacketBuffer { + icmpSize := header.ICMPv6HeaderSize + header.NDPRAMinimumSize + hdr := buffer.NewPrependable(header.IPv6MinimumSize + icmpSize) + pkt := header.ICMPv6(hdr.Prepend(icmpSize)) + pkt.SetType(header.ICMPv6RouterAdvert) + pkt.SetCode(0) + // Populate the Router Lifetime. + binary.BigEndian.PutUint16(pkt.NDPPayload()[2:], rl) + pkt.SetChecksum(header.ICMPv6Checksum(pkt, ip, header.IPv6AllNodesMulticastAddress, buffer.VectorisedView{})) + payloadLength := hdr.UsedLength() + iph := header.IPv6(hdr.Prepend(header.IPv6MinimumSize)) + iph.Encode(&header.IPv6Fields{ + PayloadLength: uint16(payloadLength), + NextHeader: uint8(icmp.ProtocolNumber6), + HopLimit: header.NDPHopLimit, + SrcAddr: ip, + DstAddr: header.IPv6AllNodesMulticastAddress, + }) + + return tcpip.PacketBuffer{Data: hdr.View().ToVectorisedView()} +} + +// TestNoRouterDiscovery tests that router discovery will not be performed if +// configured not to. +func TestNoRouterDiscovery(t *testing.T) { + // Being configured to discover routers means handle and + // discover are set to true and forwarding is set to false. + // This tests all possible combinations of the configurations, + // except for the configuration where handle = true, discover = + // true and forwarding = false (the required configuration to do + // router discovery) - that will done in other tests. + for i := 0; i < 7; i++ { + handle := i&1 != 0 + discover := i&2 != 0 + forwarding := i&4 == 0 + + t.Run(fmt.Sprintf("HandleRAs(%t), DiscoverDefaultRouters(%t), Forwarding(%t)", handle, discover, forwarding), func(t *testing.T) { + ndpDisp := ndpDispatcher{ + routerC: make(chan ndpRouterEvent, 10), + } + e := channel.New(10, 1280, linkAddr1) + s := stack.New(stack.Options{ + NetworkProtocols: []stack.NetworkProtocol{ipv6.NewProtocol()}, + NDPConfigs: stack.NDPConfigurations{ + HandleRAs: handle, + DiscoverDefaultRouters: discover, + }, + NDPDisp: &ndpDisp, + }) + s.SetForwarding(forwarding) + + if err := s.CreateNIC(1, e); err != nil { + t.Fatalf("CreateNIC(1) = %s", err) + } + + // Rx an RA with non-zero lifetime. + e.InjectInbound(header.IPv6ProtocolNumber, raBuf(llAddr2, 1000)) + select { + case <-ndpDisp.routerC: + t.Fatal("unexpectedly discovered a router when configured not to") + case <-time.After(defaultTimeout): + } + }) + } +} + +// TestRouterDiscoveryDispatcherNoRemember tests that the stack does not +// remember a discovered router when the dispatcher asks it not to. +func TestRouterDiscoveryDispatcherNoRemember(t *testing.T) { + ndpDisp := ndpDispatcher{ + routerC: make(chan ndpRouterEvent, 10), + } + e := channel.New(10, 1280, linkAddr1) + s := stack.New(stack.Options{ + NetworkProtocols: []stack.NetworkProtocol{ipv6.NewProtocol()}, + NDPConfigs: stack.NDPConfigurations{ + HandleRAs: true, + DiscoverDefaultRouters: true, + }, + NDPDisp: &ndpDisp, + }) + + if err := s.CreateNIC(1, e); err != nil { + t.Fatalf("CreateNIC(1) = %s", err) + } + + routeTable := []tcpip.Route{ + { + header.IPv6EmptySubnet, + llAddr3, + 1, + }, + } + s.SetRouteTable(routeTable) + + // Rx an RA with short lifetime. + lifetime := time.Duration(1) + e.InjectInbound(header.IPv6ProtocolNumber, raBuf(llAddr2, uint16(lifetime))) + select { + case r := <-ndpDisp.routerC: + if r.nicid != 1 { + t.Fatalf("got r.nicid = %d, want = 1", r.nicid) + } + if r.addr != llAddr2 { + t.Fatalf("got r.addr = %s, want = %s", r.addr, llAddr2) + } + if !r.discovered { + t.Fatal("got r.discovered = false, want = true") + } + case <-time.After(defaultTimeout): + t.Fatal("timeout waiting for router discovery event") + } + + // Original route table should not have been modified. + if got := s.GetRouteTable(); !cmp.Equal(got, routeTable) { + t.Fatalf("got GetRouteTable = %v, want = %v", got, routeTable) + } + + // Wait for the normal invalidation time plus an extra second to + // make sure we do not actually receive any invalidation events as + // we should not have remembered the router in the first place. + select { + case <-ndpDisp.routerC: + t.Fatal("should not have received any router events") + case <-time.After(lifetime*time.Second + defaultTimeout): + } + + // Original route table should not have been modified. + if got := s.GetRouteTable(); !cmp.Equal(got, routeTable) { + t.Fatalf("got GetRouteTable = %v, want = %v", got, routeTable) + } +} + +func TestRouterDiscovery(t *testing.T) { + ndpDisp := ndpDispatcher{ + routerC: make(chan ndpRouterEvent, 10), + rememberRouter: true, + } + e := channel.New(10, 1280, linkAddr1) + s := stack.New(stack.Options{ + NetworkProtocols: []stack.NetworkProtocol{ipv6.NewProtocol()}, + NDPConfigs: stack.NDPConfigurations{ + HandleRAs: true, + DiscoverDefaultRouters: true, + }, + NDPDisp: &ndpDisp, + }) + + waitForEvent := func(addr tcpip.Address, discovered bool, timeout time.Duration) { + t.Helper() + + select { + case r := <-ndpDisp.routerC: + if r.nicid != 1 { + t.Fatalf("got r.nicid = %d, want = 1", r.nicid) + } + if r.addr != addr { + t.Fatalf("got r.addr = %s, want = %s", r.addr, addr) + } + if r.discovered != discovered { + t.Fatalf("got r.discovered = %t, want = %t", r.discovered, discovered) + } + case <-time.After(timeout): + t.Fatal("timeout waiting for router discovery event") + } + } + + if err := s.CreateNIC(1, e); err != nil { + t.Fatalf("CreateNIC(1) = %s", err) + } + + // Rx an RA from lladdr2 with zero lifetime. It should not be + // remembered. + e.InjectInbound(header.IPv6ProtocolNumber, raBuf(llAddr2, 0)) + select { + case <-ndpDisp.routerC: + t.Fatal("unexpectedly discovered a router with 0 lifetime") + case <-time.After(defaultTimeout): + } + + // Rx an RA from lladdr2 with a huge lifetime. + e.InjectInbound(header.IPv6ProtocolNumber, raBuf(llAddr2, 1000)) + waitForEvent(llAddr2, true, defaultTimeout) + + // Should have a default route through the discovered router. + if got, want := s.GetRouteTable(), []tcpip.Route{{header.IPv6EmptySubnet, llAddr2, 1}}; !cmp.Equal(got, want) { + t.Fatalf("got GetRouteTable = %v, want = %v", got, want) + } + + // Rx an RA from another router (lladdr3) with non-zero lifetime. + l3Lifetime := time.Duration(6) + e.InjectInbound(header.IPv6ProtocolNumber, raBuf(llAddr3, uint16(l3Lifetime))) + waitForEvent(llAddr3, true, defaultTimeout) + + // Should have default routes through the discovered routers. + if got, want := s.GetRouteTable(), []tcpip.Route{{header.IPv6EmptySubnet, llAddr2, 1}, {header.IPv6EmptySubnet, llAddr3, 1}}; !cmp.Equal(got, want) { + t.Fatalf("got GetRouteTable = %v, want = %v", got, want) + } + + // Rx an RA from lladdr2 with lesser lifetime. + l2Lifetime := time.Duration(2) + e.InjectInbound(header.IPv6ProtocolNumber, raBuf(llAddr2, uint16(l2Lifetime))) + select { + case <-ndpDisp.routerC: + t.Fatal("Should not receive a router event when updating lifetimes for known routers") + case <-time.After(defaultTimeout): + } + + // Should still have a default route through the discovered routers. + if got, want := s.GetRouteTable(), []tcpip.Route{{header.IPv6EmptySubnet, llAddr2, 1}, {header.IPv6EmptySubnet, llAddr3, 1}}; !cmp.Equal(got, want) { + t.Fatalf("got GetRouteTable = %v, want = %v", got, want) + } + + // Wait for lladdr2's router invalidation timer to fire. The lifetime + // of the router should have been updated to the most recent (smaller) + // lifetime. + // + // Wait for the normal lifetime plus an extra bit for the + // router to get invalidated. If we don't get an invalidation + // event after this time, then something is wrong. + waitForEvent(llAddr2, false, l2Lifetime*time.Second+defaultTimeout) + + // Should no longer have the default route through lladdr2. + if got, want := s.GetRouteTable(), []tcpip.Route{{header.IPv6EmptySubnet, llAddr3, 1}}; !cmp.Equal(got, want) { + t.Fatalf("got GetRouteTable = %v, want = %v", got, want) + } + + // Rx an RA from lladdr2 with huge lifetime. + e.InjectInbound(header.IPv6ProtocolNumber, raBuf(llAddr2, 1000)) + waitForEvent(llAddr2, true, defaultTimeout) + + // Should have a default route through the discovered routers. + if got, want := s.GetRouteTable(), []tcpip.Route{{header.IPv6EmptySubnet, llAddr3, 1}, {header.IPv6EmptySubnet, llAddr2, 1}}; !cmp.Equal(got, want) { + t.Fatalf("got GetRouteTable = %v, want = %v", got, want) + } + + // Rx an RA from lladdr2 with zero lifetime. It should be invalidated. + e.InjectInbound(header.IPv6ProtocolNumber, raBuf(llAddr2, 0)) + waitForEvent(llAddr2, false, defaultTimeout) + + // Should have deleted the default route through the router that just + // got invalidated. + if got, want := s.GetRouteTable(), []tcpip.Route{{header.IPv6EmptySubnet, llAddr3, 1}}; !cmp.Equal(got, want) { + t.Fatalf("got GetRouteTable = %v, want = %v", got, want) + } + + // Wait for lladdr3's router invalidation timer to fire. The lifetime + // of the router should have been updated to the most recent (smaller) + // lifetime. + // + // Wait for the normal lifetime plus an extra bit for the + // router to get invalidated. If we don't get an invalidation + // event after this time, then something is wrong. + waitForEvent(llAddr3, false, l3Lifetime*time.Second+defaultTimeout) + + // Should not have any routes now that all discovered routers have been + // invalidated. + if got := len(s.GetRouteTable()); got != 0 { + t.Fatalf("got len(s.GetRouteTable()) = %d, want = 0", got) + } +} + +// TestRouterDiscoveryMaxRouters tests that only +// stack.MaxDiscoveredDefaultRouters discovered routers are remembered. +func TestRouterDiscoveryMaxRouters(t *testing.T) { + ndpDisp := ndpDispatcher{ + routerC: make(chan ndpRouterEvent, 10), + rememberRouter: true, + } + e := channel.New(10, 1280, linkAddr1) + s := stack.New(stack.Options{ + NetworkProtocols: []stack.NetworkProtocol{ipv6.NewProtocol()}, + NDPConfigs: stack.NDPConfigurations{ + HandleRAs: true, + DiscoverDefaultRouters: true, + }, + NDPDisp: &ndpDisp, + }) + + if err := s.CreateNIC(1, e); err != nil { + t.Fatalf("CreateNIC(1) = %s", err) + } + + expectedRt := [stack.MaxDiscoveredDefaultRouters]tcpip.Route{} + + // Receive an RA from 2 more than the max number of discovered routers. + for i := 1; i <= stack.MaxDiscoveredDefaultRouters+2; i++ { + linkAddr := []byte{2, 2, 3, 4, 5, 0} + linkAddr[5] = byte(i) + llAddr := header.LinkLocalAddr(tcpip.LinkAddress(linkAddr)) + + e.InjectInbound(header.IPv6ProtocolNumber, raBuf(llAddr, 5)) + + if i <= stack.MaxDiscoveredDefaultRouters { + expectedRt[i-1] = tcpip.Route{header.IPv6EmptySubnet, llAddr, 1} + select { + case r := <-ndpDisp.routerC: + if r.nicid != 1 { + t.Fatalf("got r.nicid = %d, want = 1", r.nicid) + } + if r.addr != llAddr { + t.Fatalf("got r.addr = %s, want = %s", r.addr, llAddr) + } + if !r.discovered { + t.Fatal("got r.discovered = false, want = true") + } + case <-time.After(defaultTimeout): + t.Fatal("timeout waiting for router discovery event") + } + + } else { + select { + case <-ndpDisp.routerC: + t.Fatal("should not have discovered a new router after we already discovered the max number of routers") + case <-time.After(defaultTimeout): + } + } + } + + // Should only have default routes for the first + // stack.MaxDiscoveredDefaultRouters discovered routers. + if got := s.GetRouteTable(); !cmp.Equal(got, expectedRt[:]) { + t.Fatalf("got GetRouteTable = %v, want = %v", got, expectedRt) + } +} diff --git a/pkg/tcpip/tcpip.go b/pkg/tcpip/tcpip.go index 03be7d3d4..3edb513d4 100644 --- a/pkg/tcpip/tcpip.go +++ b/pkg/tcpip/tcpip.go @@ -231,6 +231,13 @@ func (s *Subnet) Broadcast() Address { return Address(addr) } +// Equal returns true if s equals o. +// +// Needed to use cmp.Equal on Subnet as its fields are unexported. +func (s Subnet) Equal(o Subnet) bool { + return s == o +} + // NICID is a number that uniquely identifies a NIC. type NICID int32 |