diff options
Diffstat (limited to 'pkg')
| -rw-r--r-- | pkg/tcpip/checker/checker.go | 6 | ||||
| -rw-r--r-- | pkg/tcpip/header/BUILD | 1 | ||||
| -rw-r--r-- | pkg/tcpip/header/ipv6.go | 7 | ||||
| -rw-r--r-- | pkg/tcpip/header/ndp_router_solicit.go | 36 | ||||
| -rw-r--r-- | pkg/tcpip/stack/BUILD | 2 | ||||
| -rw-r--r-- | pkg/tcpip/stack/ndp.go | 175 | ||||
| -rw-r--r-- | pkg/tcpip/stack/ndp_test.go | 224 | ||||
| -rw-r--r-- | pkg/tcpip/stack/nic.go | 73 | ||||
| -rw-r--r-- | pkg/tcpip/stack/stack.go | 8 |
9 files changed, 486 insertions, 46 deletions
diff --git a/pkg/tcpip/checker/checker.go b/pkg/tcpip/checker/checker.go index 542abc99d..885d773b0 100644 --- a/pkg/tcpip/checker/checker.go +++ b/pkg/tcpip/checker/checker.go @@ -770,3 +770,9 @@ func NDPNSTargetAddress(want tcpip.Address) TransportChecker { } } } + +// NDPRS creates a checker that checks that the packet contains a valid NDP +// Router Solicitation message (as per the raw wire format). +func NDPRS() NetworkChecker { + return NDP(header.ICMPv6RouterSolicit, header.NDPRSMinimumSize) +} diff --git a/pkg/tcpip/header/BUILD b/pkg/tcpip/header/BUILD index f2061c778..cd747d100 100644 --- a/pkg/tcpip/header/BUILD +++ b/pkg/tcpip/header/BUILD @@ -20,6 +20,7 @@ go_library( "ndp_neighbor_solicit.go", "ndp_options.go", "ndp_router_advert.go", + "ndp_router_solicit.go", "tcp.go", "udp.go", ], diff --git a/pkg/tcpip/header/ipv6.go b/pkg/tcpip/header/ipv6.go index 83425c614..70e6ce095 100644 --- a/pkg/tcpip/header/ipv6.go +++ b/pkg/tcpip/header/ipv6.go @@ -84,6 +84,13 @@ const ( // The address is ff02::1. IPv6AllNodesMulticastAddress tcpip.Address = "\xff\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01" + // IPv6AllRoutersMulticastAddress is a link-local multicast group that + // all IPv6 routers MUST join, as per RFC 4291, section 2.8. Packets + // destined to this address will reach all routers on a link. + // + // The address is ff02::2. + IPv6AllRoutersMulticastAddress tcpip.Address = "\xff\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02" + // IPv6MinimumMTU is the minimum MTU required by IPv6, per RFC 2460, // section 5. IPv6MinimumMTU = 1280 diff --git a/pkg/tcpip/header/ndp_router_solicit.go b/pkg/tcpip/header/ndp_router_solicit.go new file mode 100644 index 000000000..9e67ba95d --- /dev/null +++ b/pkg/tcpip/header/ndp_router_solicit.go @@ -0,0 +1,36 @@ +// Copyright 2019 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package header + +// NDPRouterSolicit is an NDP Router Solicitation message. It will only contain +// the body of an ICMPv6 packet. +// +// See RFC 4861 section 4.1 for more details. +type NDPRouterSolicit []byte + +const ( + // NDPRSMinimumSize is the minimum size of a valid NDP Router + // Solicitation message (body of an ICMPv6 packet). + NDPRSMinimumSize = 4 + + // ndpRSOptionsOffset is the start of the NDP options in an + // NDPRouterSolicit. + ndpRSOptionsOffset = 4 +) + +// Options returns an NDPOptions of the the options body. +func (b NDPRouterSolicit) Options() NDPOptions { + return NDPOptions(b[ndpRSOptionsOffset:]) +} diff --git a/pkg/tcpip/stack/BUILD b/pkg/tcpip/stack/BUILD index 705e984c1..783351a69 100644 --- a/pkg/tcpip/stack/BUILD +++ b/pkg/tcpip/stack/BUILD @@ -51,7 +51,7 @@ go_library( go_test( name = "stack_x_test", - size = "small", + size = "medium", srcs = [ "ndp_test.go", "stack_test.go", diff --git a/pkg/tcpip/stack/ndp.go b/pkg/tcpip/stack/ndp.go index a9dd322db..acefc356a 100644 --- a/pkg/tcpip/stack/ndp.go +++ b/pkg/tcpip/stack/ndp.go @@ -17,6 +17,7 @@ package stack import ( "fmt" "log" + "math/rand" "time" "gvisor.dev/gvisor/pkg/tcpip" @@ -38,24 +39,36 @@ const ( // Default = 1s (from RFC 4861 section 10). defaultRetransmitTimer = time.Second + // defaultMaxRtrSolicitations is the default number of Router + // Solicitation messages to send when a NIC becomes enabled. + // + // Default = 3 (from RFC 4861 section 10). + defaultMaxRtrSolicitations = 3 + + // defaultRtrSolicitationInterval is the default amount of time between + // sending Router Solicitation messages. + // + // Default = 4s (from 4861 section 10). + defaultRtrSolicitationInterval = 4 * time.Second + + // defaultMaxRtrSolicitationDelay is the default maximum amount of time + // to wait before sending the first Router Solicitation message. + // + // Default = 1s (from 4861 section 10). + defaultMaxRtrSolicitationDelay = time.Second + // defaultHandleRAs is the default configuration for whether or not to // handle incoming Router Advertisements as a host. - // - // Default = true. defaultHandleRAs = true // defaultDiscoverDefaultRouters is the default configuration for // whether or not to discover default routers from incoming Router // Advertisements, as a host. - // - // Default = true. defaultDiscoverDefaultRouters = true // defaultDiscoverOnLinkPrefixes is the default configuration for // whether or not to discover on-link prefixes from incoming Router // Advertisements' Prefix Information option, as a host. - // - // Default = true. defaultDiscoverOnLinkPrefixes = true // defaultAutoGenGlobalAddresses is the default configuration for @@ -74,26 +87,31 @@ const ( // value of 0 means unspecified, so the smallest valid value is 1. // Note, the unit of the RetransmitTimer field in the Router // Advertisement is milliseconds. - // - // Min = 1ms. minimumRetransmitTimer = time.Millisecond + // minimumRtrSolicitationInterval is the minimum amount of time to wait + // between sending Router Solicitation messages. This limit is imposed + // to make sure that Router Solicitation messages are not sent all at + // once, defeating the purpose of sending the initial few messages. + minimumRtrSolicitationInterval = 500 * time.Millisecond + + // minimumMaxRtrSolicitationDelay is the minimum amount of time to wait + // before sending the first Router Solicitation message. It is 0 because + // we cannot have a negative delay. + minimumMaxRtrSolicitationDelay = 0 + // MaxDiscoveredDefaultRouters is the maximum number of discovered // 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 // MaxDiscoveredOnLinkPrefixes is the maximum number of discovered // on-link prefixes. The stack should stop discovering new on-link // prefixes after discovering MaxDiscoveredOnLinkPrefixes on-link // prefixes. - // - // Max = 10. MaxDiscoveredOnLinkPrefixes = 10 // validPrefixLenForAutoGen is the expected prefix length that an @@ -245,9 +263,24 @@ type NDPConfigurations struct { // The amount of time to wait between sending Neighbor solicitation // messages. // - // Must be greater than 0.5s. + // Must be greater than or equal to 1ms. RetransmitTimer time.Duration + // The number of Router Solicitation messages to send when the NIC + // becomes enabled. + MaxRtrSolicitations uint8 + + // The amount of time between transmitting Router Solicitation messages. + // + // Must be greater than or equal to 0.5s. + RtrSolicitationInterval time.Duration + + // The maximum amount of time before transmitting the first Router + // Solicitation message. + // + // Must be greater than or equal to 0s. + MaxRtrSolicitationDelay time.Duration + // HandleRAs determines whether or not Router Advertisements will be // processed. HandleRAs bool @@ -278,12 +311,15 @@ type NDPConfigurations struct { // default values. func DefaultNDPConfigurations() NDPConfigurations { return NDPConfigurations{ - DupAddrDetectTransmits: defaultDupAddrDetectTransmits, - RetransmitTimer: defaultRetransmitTimer, - HandleRAs: defaultHandleRAs, - DiscoverDefaultRouters: defaultDiscoverDefaultRouters, - DiscoverOnLinkPrefixes: defaultDiscoverOnLinkPrefixes, - AutoGenGlobalAddresses: defaultAutoGenGlobalAddresses, + DupAddrDetectTransmits: defaultDupAddrDetectTransmits, + RetransmitTimer: defaultRetransmitTimer, + MaxRtrSolicitations: defaultMaxRtrSolicitations, + RtrSolicitationInterval: defaultRtrSolicitationInterval, + MaxRtrSolicitationDelay: defaultMaxRtrSolicitationDelay, + HandleRAs: defaultHandleRAs, + DiscoverDefaultRouters: defaultDiscoverDefaultRouters, + DiscoverOnLinkPrefixes: defaultDiscoverOnLinkPrefixes, + AutoGenGlobalAddresses: defaultAutoGenGlobalAddresses, } } @@ -292,10 +328,24 @@ func DefaultNDPConfigurations() NDPConfigurations { // // If RetransmitTimer is less than minimumRetransmitTimer, then a value of // defaultRetransmitTimer will be used. +// +// If RtrSolicitationInterval is less than minimumRtrSolicitationInterval, then +// a value of defaultRtrSolicitationInterval will be used. +// +// If MaxRtrSolicitationDelay is less than minimumMaxRtrSolicitationDelay, then +// a value of defaultMaxRtrSolicitationDelay will be used. func (c *NDPConfigurations) validate() { if c.RetransmitTimer < minimumRetransmitTimer { c.RetransmitTimer = defaultRetransmitTimer } + + if c.RtrSolicitationInterval < minimumRtrSolicitationInterval { + c.RtrSolicitationInterval = defaultRtrSolicitationInterval + } + + if c.MaxRtrSolicitationDelay < minimumMaxRtrSolicitationDelay { + c.MaxRtrSolicitationDelay = defaultMaxRtrSolicitationDelay + } } // ndpState is the per-interface NDP state. @@ -316,6 +366,10 @@ type ndpState struct { // Information option. onLinkPrefixes map[tcpip.Subnet]onLinkPrefixState + // The timer used to send the next router solicitation message. + // If routers are being solicited, rtrSolicitTimer MUST NOT be nil. + rtrSolicitTimer *time.Timer + // The addresses generated by SLAAC. autoGenAddresses map[tcpip.Address]autoGenAddressState @@ -501,10 +555,12 @@ func (ndp *ndpState) doDuplicateAddressDetection(addr tcpip.Address, remaining u // address. panic(fmt.Sprintf("ndpdad: NIC(%d) is not in the solicited-node multicast group (%s) but it has addr %s", ndp.nic.ID(), snmc, addr)) } + snmcRef.incRef() // Use the unspecified address as the source address when performing // DAD. r := makeRoute(header.IPv6ProtocolNumber, header.IPv6Any, snmc, ndp.nic.linkEP.LinkAddress(), snmcRef, false, false) + defer r.Release() hdr := buffer.NewPrependable(int(r.MaxHeaderLength()) + header.ICMPv6NeighborSolicitMinimumSize) pkt := header.ICMPv6(hdr.Prepend(header.ICMPv6NeighborSolicitMinimumSize)) @@ -1132,3 +1188,84 @@ func (ndp *ndpState) cleanupHostOnlyState() { log.Fatalf("ndp: still have discovered default routers after cleaning up, found = %d", got) } } + +// startSolicitingRouters starts soliciting routers, as per RFC 4861 section +// 6.3.7. If routers are already being solicited, this function does nothing. +// +// The NIC ndp belongs to MUST be locked. +func (ndp *ndpState) startSolicitingRouters() { + if ndp.rtrSolicitTimer != nil { + // We are already soliciting routers. + return + } + + remaining := ndp.configs.MaxRtrSolicitations + if remaining == 0 { + return + } + + // Calculate the random delay before sending our first RS, as per RFC + // 4861 section 6.3.7. + var delay time.Duration + if ndp.configs.MaxRtrSolicitationDelay > 0 { + delay = time.Duration(rand.Int63n(int64(ndp.configs.MaxRtrSolicitationDelay))) + } + + ndp.rtrSolicitTimer = time.AfterFunc(delay, func() { + // Send an RS message with the unspecified source address. + ref := ndp.nic.getRefOrCreateTemp(header.IPv6ProtocolNumber, header.IPv6Any, NeverPrimaryEndpoint, true) + r := makeRoute(header.IPv6ProtocolNumber, header.IPv6Any, header.IPv6AllRoutersMulticastAddress, ndp.nic.linkEP.LinkAddress(), ref, false, false) + defer r.Release() + + payloadSize := header.ICMPv6HeaderSize + header.NDPRSMinimumSize + hdr := buffer.NewPrependable(header.IPv6MinimumSize + payloadSize) + pkt := header.ICMPv6(hdr.Prepend(payloadSize)) + pkt.SetType(header.ICMPv6RouterSolicit) + pkt.SetChecksum(header.ICMPv6Checksum(pkt, r.LocalAddress, r.RemoteAddress, buffer.VectorisedView{})) + + sent := r.Stats().ICMP.V6PacketsSent + if err := r.WritePacket(nil, + NetworkHeaderParams{ + Protocol: header.ICMPv6ProtocolNumber, + TTL: header.NDPHopLimit, + TOS: DefaultTOS, + }, tcpip.PacketBuffer{Header: hdr}, + ); err != nil { + sent.Dropped.Increment() + log.Printf("startSolicitingRouters: error writing NDP router solicit message on NIC(%d); err = %s", ndp.nic.ID(), err) + // Don't send any more messages if we had an error. + remaining = 0 + } else { + sent.RouterSolicit.Increment() + remaining-- + } + + ndp.nic.mu.Lock() + defer ndp.nic.mu.Unlock() + if remaining == 0 { + ndp.rtrSolicitTimer = nil + } else if ndp.rtrSolicitTimer != nil { + // Note, we need to explicitly check to make sure that + // the timer field is not nil because if it was nil but + // we still reached this point, then we know the NIC + // was requested to stop soliciting routers so we don't + // need to send the next Router Solicitation message. + ndp.rtrSolicitTimer.Reset(ndp.configs.RtrSolicitationInterval) + } + }) + +} + +// stopSolicitingRouters stops soliciting routers. If routers are not currently +// being solicited, this function does nothing. +// +// The NIC ndp belongs to MUST be locked. +func (ndp *ndpState) stopSolicitingRouters() { + if ndp.rtrSolicitTimer == nil { + // Nothing to do. + return + } + + ndp.rtrSolicitTimer.Stop() + ndp.rtrSolicitTimer = nil +} diff --git a/pkg/tcpip/stack/ndp_test.go b/pkg/tcpip/stack/ndp_test.go index d390c6312..7c68e8ed4 100644 --- a/pkg/tcpip/stack/ndp_test.go +++ b/pkg/tcpip/stack/ndp_test.go @@ -3098,3 +3098,227 @@ func TestDHCPv6ConfigurationFromNDPDA(t *testing.T) { e.InjectInbound(header.IPv6ProtocolNumber, raBufWithDHCPv6(llAddr2, false, true)) expectNoDHCPv6Event() } + +// TestRouterSolicitation tests the initial Router Solicitations that are sent +// when a NIC newly becomes enabled. +func TestRouterSolicitation(t *testing.T) { + t.Parallel() + + tests := []struct { + name string + maxRtrSolicit uint8 + rtrSolicitInt time.Duration + effectiveRtrSolicitInt time.Duration + maxRtrSolicitDelay time.Duration + effectiveMaxRtrSolicitDelay time.Duration + }{ + { + name: "Single RS with delay", + maxRtrSolicit: 1, + rtrSolicitInt: time.Second, + effectiveRtrSolicitInt: time.Second, + maxRtrSolicitDelay: time.Second, + effectiveMaxRtrSolicitDelay: time.Second, + }, + { + name: "Two RS with delay", + maxRtrSolicit: 2, + rtrSolicitInt: time.Second, + effectiveRtrSolicitInt: time.Second, + maxRtrSolicitDelay: 500 * time.Millisecond, + effectiveMaxRtrSolicitDelay: 500 * time.Millisecond, + }, + { + name: "Single RS without delay", + maxRtrSolicit: 1, + rtrSolicitInt: time.Second, + effectiveRtrSolicitInt: time.Second, + maxRtrSolicitDelay: 0, + effectiveMaxRtrSolicitDelay: 0, + }, + { + name: "Two RS without delay and invalid zero interval", + maxRtrSolicit: 2, + rtrSolicitInt: 0, + effectiveRtrSolicitInt: 4 * time.Second, + maxRtrSolicitDelay: 0, + effectiveMaxRtrSolicitDelay: 0, + }, + { + name: "Three RS without delay", + maxRtrSolicit: 3, + rtrSolicitInt: 500 * time.Millisecond, + effectiveRtrSolicitInt: 500 * time.Millisecond, + maxRtrSolicitDelay: 0, + effectiveMaxRtrSolicitDelay: 0, + }, + { + name: "Two RS with invalid negative delay", + maxRtrSolicit: 2, + rtrSolicitInt: time.Second, + effectiveRtrSolicitInt: time.Second, + maxRtrSolicitDelay: -3 * time.Second, + effectiveMaxRtrSolicitDelay: time.Second, + }, + } + + // This Run will not return until the parallel tests finish. + // + // We need this because we need to do some teardown work after the + // parallel tests complete. + // + // See https://godoc.org/testing#hdr-Subtests_and_Sub_benchmarks for + // more details. + t.Run("group", func(t *testing.T) { + for _, test := range tests { + test := test + + t.Run(test.name, func(t *testing.T) { + t.Parallel() + e := channel.New(int(test.maxRtrSolicit), 1280, linkAddr1) + waitForPkt := func(timeout time.Duration) { + t.Helper() + select { + case p := <-e.C: + if p.Proto != header.IPv6ProtocolNumber { + t.Fatalf("got Proto = %d, want = %d", p.Proto, header.IPv6ProtocolNumber) + } + checker.IPv6(t, + p.Pkt.Header.View(), + checker.SrcAddr(header.IPv6Any), + checker.DstAddr(header.IPv6AllRoutersMulticastAddress), + checker.TTL(header.NDPHopLimit), + checker.NDPRS(), + ) + + case <-time.After(timeout): + t.Fatal("timed out waiting for packet") + } + } + waitForNothing := func(timeout time.Duration) { + t.Helper() + select { + case <-e.C: + t.Fatal("unexpectedly got a packet") + case <-time.After(timeout): + } + } + s := stack.New(stack.Options{ + NetworkProtocols: []stack.NetworkProtocol{ipv6.NewProtocol()}, + NDPConfigs: stack.NDPConfigurations{ + MaxRtrSolicitations: test.maxRtrSolicit, + RtrSolicitationInterval: test.rtrSolicitInt, + MaxRtrSolicitationDelay: test.maxRtrSolicitDelay, + }, + }) + if err := s.CreateNIC(1, e); err != nil { + t.Fatalf("CreateNIC(1) = %s", err) + } + + // Make sure each RS got sent at the right + // times. + remaining := test.maxRtrSolicit + if remaining > 0 { + waitForPkt(test.effectiveMaxRtrSolicitDelay + defaultTimeout) + remaining-- + } + for ; remaining > 0; remaining-- { + waitForNothing(test.effectiveRtrSolicitInt - defaultTimeout) + waitForPkt(2 * defaultTimeout) + } + + // Make sure no more RS. + if test.effectiveRtrSolicitInt > test.effectiveMaxRtrSolicitDelay { + waitForNothing(test.effectiveRtrSolicitInt + defaultTimeout) + } else { + waitForNothing(test.effectiveMaxRtrSolicitDelay + defaultTimeout) + } + + // Make sure the counter got properly + // incremented. + if got, want := s.Stats().ICMP.V6PacketsSent.RouterSolicit.Value(), uint64(test.maxRtrSolicit); got != want { + t.Fatalf("got sent RouterSolicit = %d, want = %d", got, want) + } + }) + } + }) +} + +// TestStopStartSolicitingRouters tests that when forwarding is enabled or +// disabled, router solicitations are stopped or started, respecitively. +func TestStopStartSolicitingRouters(t *testing.T) { + t.Parallel() + + const interval = 500 * time.Millisecond + const delay = time.Second + const maxRtrSolicitations = 3 + e := channel.New(maxRtrSolicitations, 1280, linkAddr1) + waitForPkt := func(timeout time.Duration) { + t.Helper() + select { + case p := <-e.C: + if p.Proto != header.IPv6ProtocolNumber { + t.Fatalf("got Proto = %d, want = %d", p.Proto, header.IPv6ProtocolNumber) + } + checker.IPv6(t, p.Pkt.Header.View(), + checker.SrcAddr(header.IPv6Any), + checker.DstAddr(header.IPv6AllRoutersMulticastAddress), + checker.TTL(header.NDPHopLimit), + checker.NDPRS()) + + case <-time.After(timeout): + t.Fatal("timed out waiting for packet") + } + } + s := stack.New(stack.Options{ + NetworkProtocols: []stack.NetworkProtocol{ipv6.NewProtocol()}, + NDPConfigs: stack.NDPConfigurations{ + MaxRtrSolicitations: maxRtrSolicitations, + RtrSolicitationInterval: interval, + MaxRtrSolicitationDelay: delay, + }, + }) + if err := s.CreateNIC(1, e); err != nil { + t.Fatalf("CreateNIC(1) = %s", err) + } + + // Enable forwarding which should stop router solicitations. + s.SetForwarding(true) + select { + case <-e.C: + // A single RS may have been sent before forwarding was enabled. + select { + case <-e.C: + t.Fatal("Should not have sent more than one RS message") + case <-time.After(interval + defaultTimeout): + } + case <-time.After(delay + defaultTimeout): + } + + // Enabling forwarding again should do nothing. + s.SetForwarding(true) + select { + case <-e.C: + t.Fatal("unexpectedly got a packet after becoming a router") + case <-time.After(delay + defaultTimeout): + } + + // Disable forwarding which should start router solicitations. + s.SetForwarding(false) + waitForPkt(delay + defaultTimeout) + waitForPkt(interval + defaultTimeout) + waitForPkt(interval + defaultTimeout) + select { + case <-e.C: + t.Fatal("unexpectedly got an extra packet after sending out the expected RSs") + case <-time.After(interval + defaultTimeout): + } + + // Disabling forwarding again should do nothing. + s.SetForwarding(false) + select { + case <-e.C: + t.Fatal("unexpectedly got a packet after becoming a router") + case <-time.After(delay + defaultTimeout): + } +} diff --git a/pkg/tcpip/stack/nic.go b/pkg/tcpip/stack/nic.go index 071221d5a..1089fdf35 100644 --- a/pkg/tcpip/stack/nic.go +++ b/pkg/tcpip/stack/nic.go @@ -177,49 +177,72 @@ func (n *NIC) enable() *tcpip.Error { } // Do not auto-generate an IPv6 link-local address for loopback devices. - if !n.stack.autoGenIPv6LinkLocal || n.isLoopback() { - return nil - } + if n.stack.autoGenIPv6LinkLocal && !n.isLoopback() { + var addr tcpip.Address + if oIID := n.stack.opaqueIIDOpts; oIID.NICNameFromID != nil { + addr = header.LinkLocalAddrWithOpaqueIID(oIID.NICNameFromID(n.ID(), n.name), 0, oIID.SecretKey) + } else { + l2addr := n.linkEP.LinkAddress() - var addr tcpip.Address - if oIID := n.stack.opaqueIIDOpts; oIID.NICNameFromID != nil { - addr = header.LinkLocalAddrWithOpaqueIID(oIID.NICNameFromID(n.ID(), n.name), 0, oIID.SecretKey) - } else { - l2addr := n.linkEP.LinkAddress() + // Only attempt to generate the link-local address if we have a valid MAC + // address. + // + // TODO(b/141011931): Validate a LinkEndpoint's link address (provided by + // LinkEndpoint.LinkAddress) before reaching this point. + if !header.IsValidUnicastEthernetAddress(l2addr) { + return nil + } - // Only attempt to generate the link-local address if we have a valid MAC - // address. - // - // TODO(b/141011931): Validate a LinkEndpoint's link address (provided by - // LinkEndpoint.LinkAddress) before reaching this point. - if !header.IsValidUnicastEthernetAddress(l2addr) { - return nil + addr = header.LinkLocalAddr(l2addr) } - addr = header.LinkLocalAddr(l2addr) + if _, err := n.addPermanentAddressLocked(tcpip.ProtocolAddress{ + Protocol: header.IPv6ProtocolNumber, + AddressWithPrefix: tcpip.AddressWithPrefix{ + Address: addr, + PrefixLen: header.IPv6LinkLocalPrefix.PrefixLen, + }, + }, CanBePrimaryEndpoint); err != nil { + return err + } } - _, err := n.addPermanentAddressLocked(tcpip.ProtocolAddress{ - Protocol: header.IPv6ProtocolNumber, - AddressWithPrefix: tcpip.AddressWithPrefix{ - Address: addr, - PrefixLen: header.IPv6LinkLocalPrefix.PrefixLen, - }, - }, CanBePrimaryEndpoint) + // If we are operating as a router, then do not solicit routers since we + // won't process the RAs anyways. + // + // Routers do not process Router Advertisements (RA) the same way a host + // does. That is, routers do not learn from RAs (e.g. on-link prefixes + // and default routers). Therefore, soliciting RAs from other routers on + // a link is unnecessary for routers. + if !n.stack.forwarding { + n.ndp.startSolicitingRouters() + } - return err + return nil } // becomeIPv6Router transitions n into an IPv6 router. // // When transitioning into an IPv6 router, host-only state (NDP discovered // routers, discovered on-link prefixes, and auto-generated addresses) will -// be cleaned up/invalidated. +// be cleaned up/invalidated and NDP router solicitations will be stopped. func (n *NIC) becomeIPv6Router() { n.mu.Lock() defer n.mu.Unlock() n.ndp.cleanupHostOnlyState() + n.ndp.stopSolicitingRouters() +} + +// becomeIPv6Host transitions n into an IPv6 host. +// +// When transitioning into an IPv6 host, NDP router solicitations will be +// started. +func (n *NIC) becomeIPv6Host() { + n.mu.Lock() + defer n.mu.Unlock() + + n.ndp.startSolicitingRouters() } // attachLinkEndpoint attaches the NIC to the endpoint, which will enable it diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go index 386eb6eec..fc56a6d79 100644 --- a/pkg/tcpip/stack/stack.go +++ b/pkg/tcpip/stack/stack.go @@ -750,7 +750,9 @@ func (s *Stack) Stats() tcpip.Stats { // SetForwarding enables or disables the packet forwarding between NICs. // // When forwarding becomes enabled, any host-only state on all NICs will be -// cleaned up. +// cleaned up and if IPv6 is enabled, NDP Router Solicitations will be started. +// When forwarding becomes disabled and if IPv6 is enabled, NDP Router +// Solicitations will be stopped. func (s *Stack) SetForwarding(enable bool) { // TODO(igudger, bgeffon): Expose via /proc/sys/net/ipv4/ip_forward. s.mu.Lock() @@ -772,6 +774,10 @@ func (s *Stack) SetForwarding(enable bool) { for _, nic := range s.nics { nic.becomeIPv6Router() } + } else { + for _, nic := range s.nics { + nic.becomeIPv6Host() + } } } |