From debd213da61cf35d7c91346820e93fc87bfa5896 Mon Sep 17 00:00:00 2001 From: Tamir Duberstein Date: Mon, 13 Jan 2020 14:45:31 -0800 Subject: Allow dual stack sockets to operate on AF_INET Fixes #1490 Fixes #1495 PiperOrigin-RevId: 289523250 --- pkg/tcpip/stack/stack.go | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) (limited to 'pkg/tcpip/stack/stack.go') diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go index a47ceba54..113b457fb 100644 --- a/pkg/tcpip/stack/stack.go +++ b/pkg/tcpip/stack/stack.go @@ -547,6 +547,49 @@ type TransportEndpointInfo struct { RegisterNICID tcpip.NICID } +// AddrNetProto unwraps the specified address if it is a V4-mapped V6 address +// and returns the network protocol number to be used to communicate with the +// specified address. It returns an error if the passed address is incompatible +// with the receiver. +func (e *TransportEndpointInfo) AddrNetProto(addr tcpip.FullAddress, v6only bool) (tcpip.FullAddress, tcpip.NetworkProtocolNumber, *tcpip.Error) { + netProto := e.NetProto + switch len(addr.Addr) { + case header.IPv4AddressSize: + netProto = header.IPv4ProtocolNumber + case header.IPv6AddressSize: + if header.IsV4MappedAddress(addr.Addr) { + netProto = header.IPv4ProtocolNumber + addr.Addr = addr.Addr[header.IPv6AddressSize-header.IPv4AddressSize:] + if addr.Addr == header.IPv4Any { + addr.Addr = "" + } + } + } + + switch len(e.ID.LocalAddress) { + case header.IPv4AddressSize: + if len(addr.Addr) == header.IPv6AddressSize { + return tcpip.FullAddress{}, 0, tcpip.ErrInvalidEndpointState + } + case header.IPv6AddressSize: + if len(addr.Addr) == header.IPv4AddressSize { + return tcpip.FullAddress{}, 0, tcpip.ErrNetworkUnreachable + } + } + + switch { + case netProto == e.NetProto: + case netProto == header.IPv4ProtocolNumber && e.NetProto == header.IPv6ProtocolNumber: + if v6only { + return tcpip.FullAddress{}, 0, tcpip.ErrNoRoute + } + default: + return tcpip.FullAddress{}, 0, tcpip.ErrInvalidEndpointState + } + + return addr, netProto, nil +} + // IsEndpointInfo is an empty method to implement the tcpip.EndpointInfo // marker interface. func (*TransportEndpointInfo) IsEndpointInfo() {} -- cgit v1.2.3 From 1ad8381eac108304f7b96162674624b34b95ec7b Mon Sep 17 00:00:00 2001 From: Ghanan Gowripalan Date: Mon, 13 Jan 2020 17:56:44 -0800 Subject: Do Source Address Selection when choosing an IPv6 source address Do Source Address Selection when choosing an IPv6 source address as per RFC 6724 section 5 rules 1-3: 1) Prefer same address 2) Prefer appropriate scope 3) Avoid deprecated addresses. A later change will update Source Address Selection to follow rules 4-8. Tests: Rule 1 & 2: stack.TestIPv6SourceAddressSelectionScopeAndSameAddress, Rule 3: stack.TestAutoGenAddrTimerDeprecation, stack.TestAutoGenAddrDeprecateFromPI PiperOrigin-RevId: 289559373 --- pkg/tcpip/header/ipv6.go | 43 ++++++++++++ pkg/tcpip/header/ipv6_test.go | 96 +++++++++++++++++++++++++- pkg/tcpip/stack/ndp_test.go | 22 ++++-- pkg/tcpip/stack/nic.go | 115 ++++++++++++++++++++++++++++++-- pkg/tcpip/stack/stack.go | 8 +-- pkg/tcpip/stack/stack_test.go | 152 ++++++++++++++++++++++++++++++++++++++++++ 6 files changed, 420 insertions(+), 16 deletions(-) (limited to 'pkg/tcpip/stack/stack.go') diff --git a/pkg/tcpip/header/ipv6.go b/pkg/tcpip/header/ipv6.go index 135a60b12..83425c614 100644 --- a/pkg/tcpip/header/ipv6.go +++ b/pkg/tcpip/header/ipv6.go @@ -333,6 +333,17 @@ func IsV6LinkLocalAddress(addr tcpip.Address) bool { return addr[0] == 0xfe && (addr[1]&0xc0) == 0x80 } +// IsV6UniqueLocalAddress determines if the provided address is an IPv6 +// unique-local address (within the prefix FC00::/7). +func IsV6UniqueLocalAddress(addr tcpip.Address) bool { + if len(addr) != IPv6AddressSize { + return false + } + // According to RFC 4193 section 3.1, a unique local address has the prefix + // FC00::/7. + return (addr[0] & 0xfe) == 0xfc +} + // AppendOpaqueInterfaceIdentifier appends a 64 bit opaque interface identifier // (IID) to buf as outlined by RFC 7217 and returns the extended buffer. // @@ -371,3 +382,35 @@ func LinkLocalAddrWithOpaqueIID(nicName string, dadCounter uint8, secretKey []by return tcpip.Address(AppendOpaqueInterfaceIdentifier(lladdrb[:IIDOffsetInIPv6Address], IPv6LinkLocalPrefix.Subnet(), nicName, dadCounter, secretKey)) } + +// IPv6AddressScope is the scope of an IPv6 address. +type IPv6AddressScope int + +const ( + // LinkLocalScope indicates a link-local address. + LinkLocalScope IPv6AddressScope = iota + + // UniqueLocalScope indicates a unique-local address. + UniqueLocalScope + + // GlobalScope indicates a global address. + GlobalScope +) + +// ScopeForIPv6Address returns the scope for an IPv6 address. +func ScopeForIPv6Address(addr tcpip.Address) (IPv6AddressScope, *tcpip.Error) { + if len(addr) != IPv6AddressSize { + return GlobalScope, tcpip.ErrBadAddress + } + + switch { + case IsV6LinkLocalAddress(addr): + return LinkLocalScope, nil + + case IsV6UniqueLocalAddress(addr): + return UniqueLocalScope, nil + + default: + return GlobalScope, nil + } +} diff --git a/pkg/tcpip/header/ipv6_test.go b/pkg/tcpip/header/ipv6_test.go index 1994003ed..29f54bc57 100644 --- a/pkg/tcpip/header/ipv6_test.go +++ b/pkg/tcpip/header/ipv6_test.go @@ -25,7 +25,13 @@ import ( "gvisor.dev/gvisor/pkg/tcpip/header" ) -const linkAddr = tcpip.LinkAddress("\x02\x02\x03\x04\x05\x06") +const ( + linkAddr = tcpip.LinkAddress("\x02\x02\x03\x04\x05\x06") + linkLocalAddr = tcpip.Address("\xfe\x80\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01") + uniqueLocalAddr1 = tcpip.Address("\xfc\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01") + uniqueLocalAddr2 = tcpip.Address("\xfd\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02") + globalAddr = tcpip.Address("\xa0\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01") +) func TestEthernetAdddressToModifiedEUI64(t *testing.T) { expectedIID := [header.IIDSize]byte{0, 2, 3, 255, 254, 4, 5, 6} @@ -206,3 +212,91 @@ func TestLinkLocalAddrWithOpaqueIID(t *testing.T) { }) } } + +func TestIsV6UniqueLocalAddress(t *testing.T) { + tests := []struct { + name string + addr tcpip.Address + expected bool + }{ + { + name: "Valid Unique 1", + addr: uniqueLocalAddr1, + expected: true, + }, + { + name: "Valid Unique 2", + addr: uniqueLocalAddr1, + expected: true, + }, + { + name: "Link Local", + addr: linkLocalAddr, + expected: false, + }, + { + name: "Global", + addr: globalAddr, + expected: false, + }, + { + name: "IPv4", + addr: "\x01\x02\x03\x04", + expected: false, + }, + } + + for _, test := range tests { + t.Run(test.name, func(t *testing.T) { + if got := header.IsV6UniqueLocalAddress(test.addr); got != test.expected { + t.Errorf("got header.IsV6UniqueLocalAddress(%s) = %t, want = %t", test.addr, got, test.expected) + } + }) + } +} + +func TestScopeForIPv6Address(t *testing.T) { + tests := []struct { + name string + addr tcpip.Address + scope header.IPv6AddressScope + err *tcpip.Error + }{ + { + name: "Unique Local", + addr: uniqueLocalAddr1, + scope: header.UniqueLocalScope, + err: nil, + }, + { + name: "Link Local", + addr: linkLocalAddr, + scope: header.LinkLocalScope, + err: nil, + }, + { + name: "Global", + addr: globalAddr, + scope: header.GlobalScope, + err: nil, + }, + { + name: "IPv4", + addr: "\x01\x02\x03\x04", + scope: header.GlobalScope, + err: tcpip.ErrBadAddress, + }, + } + + for _, test := range tests { + t.Run(test.name, func(t *testing.T) { + got, err := header.ScopeForIPv6Address(test.addr) + if err != test.err { + t.Errorf("got header.IsV6UniqueLocalAddress(%s) = (_, %v), want = (_, %v)", test.addr, err, test.err) + } + if got != test.scope { + t.Errorf("got header.IsV6UniqueLocalAddress(%s) = (%d, _), want = (%d, _)", test.addr, got, test.scope) + } + }) + } +} diff --git a/pkg/tcpip/stack/ndp_test.go b/pkg/tcpip/stack/ndp_test.go index f9bc18c55..d390c6312 100644 --- a/pkg/tcpip/stack/ndp_test.go +++ b/pkg/tcpip/stack/ndp_test.go @@ -1732,9 +1732,11 @@ func stackAndNdpDispatcherWithDefaultRoute(t *testing.T, nicID tcpip.NICID) (*nd return ndpDisp, e, s } -// addrForNewConnection returns the local address used when creating a new -// connection. -func addrForNewConnection(t *testing.T, s *stack.Stack) tcpip.Address { +// addrForNewConnectionTo returns the local address used when creating a new +// connection to addr. +func addrForNewConnectionTo(t *testing.T, s *stack.Stack, addr tcpip.FullAddress) tcpip.Address { + t.Helper() + wq := waiter.Queue{} we, ch := waiter.NewChannelEntry(nil) wq.EventRegister(&we, waiter.EventIn) @@ -1748,8 +1750,8 @@ func addrForNewConnection(t *testing.T, s *stack.Stack) tcpip.Address { if err := ep.SetSockOptBool(tcpip.V6OnlyOption, true); err != nil { t.Fatalf("SetSockOpt(tcpip.V6OnlyOption, true): %s", err) } - if err := ep.Connect(dstAddr); err != nil { - t.Fatalf("ep.Connect(%+v): %s", dstAddr, err) + if err := ep.Connect(addr); err != nil { + t.Fatalf("ep.Connect(%+v): %s", addr, err) } got, err := ep.GetLocalAddress() if err != nil { @@ -1758,9 +1760,19 @@ func addrForNewConnection(t *testing.T, s *stack.Stack) tcpip.Address { return got.Addr } +// addrForNewConnection returns the local address used when creating a new +// connection. +func addrForNewConnection(t *testing.T, s *stack.Stack) tcpip.Address { + t.Helper() + + return addrForNewConnectionTo(t, s, dstAddr) +} + // addrForNewConnectionWithAddr returns the local address used when creating a // new connection with a specific local address. func addrForNewConnectionWithAddr(t *testing.T, s *stack.Stack, addr tcpip.FullAddress) tcpip.Address { + t.Helper() + wq := waiter.Queue{} we, ch := waiter.NewChannelEntry(nil) wq.EventRegister(&we, waiter.EventIn) diff --git a/pkg/tcpip/stack/nic.go b/pkg/tcpip/stack/nic.go index fe557ccbd..abf73fe33 100644 --- a/pkg/tcpip/stack/nic.go +++ b/pkg/tcpip/stack/nic.go @@ -15,6 +15,8 @@ package stack import ( + "log" + "sort" "strings" "sync/atomic" @@ -251,13 +253,17 @@ func (n *NIC) setSpoofing(enable bool) { n.mu.Unlock() } -// primaryEndpoint returns the primary endpoint of n for the given network -// protocol. -// // primaryEndpoint will return the first non-deprecated endpoint if such an -// endpoint exists. If no non-deprecated endpoint exists, the first deprecated -// endpoint will be returned. -func (n *NIC) primaryEndpoint(protocol tcpip.NetworkProtocolNumber) *referencedNetworkEndpoint { +// endpoint exists for the given protocol and remoteAddr. If no non-deprecated +// endpoint exists, the first deprecated endpoint will be returned. +// +// If an IPv6 primary endpoint is requested, Source Address Selection (as +// defined by RFC 6724 section 5) will be performed. +func (n *NIC) primaryEndpoint(protocol tcpip.NetworkProtocolNumber, remoteAddr tcpip.Address) *referencedNetworkEndpoint { + if protocol == header.IPv6ProtocolNumber && remoteAddr != "" { + return n.primaryIPv6Endpoint(remoteAddr) + } + n.mu.RLock() defer n.mu.RUnlock() @@ -296,6 +302,103 @@ func (n *NIC) primaryEndpoint(protocol tcpip.NetworkProtocolNumber) *referencedN return deprecatedEndpoint } +// ipv6AddrCandidate is an IPv6 candidate for Source Address Selection (RFC +// 6724 section 5). +type ipv6AddrCandidate struct { + ref *referencedNetworkEndpoint + scope header.IPv6AddressScope +} + +// primaryIPv6Endpoint returns an IPv6 endpoint following Source Address +// Selection (RFC 6724 section 5). +// +// Note, only rules 1-3 are followed. +// +// remoteAddr must be a valid IPv6 address. +func (n *NIC) primaryIPv6Endpoint(remoteAddr tcpip.Address) *referencedNetworkEndpoint { + n.mu.RLock() + defer n.mu.RUnlock() + + primaryAddrs := n.primary[header.IPv6ProtocolNumber] + + if len(primaryAddrs) == 0 { + return nil + } + + // Create a candidate set of available addresses we can potentially use as a + // source address. + cs := make([]ipv6AddrCandidate, 0, len(primaryAddrs)) + for _, r := range primaryAddrs { + // If r is not valid for outgoing connections, it is not a valid endpoint. + if !r.isValidForOutgoing() { + continue + } + + addr := r.ep.ID().LocalAddress + scope, err := header.ScopeForIPv6Address(addr) + if err != nil { + // Should never happen as we got r from the primary IPv6 endpoint list and + // ScopeForIPv6Address only returns an error if addr is not an IPv6 + // address. + log.Fatalf("header.ScopeForIPv6Address(%s): %s", addr, err) + } + + cs = append(cs, ipv6AddrCandidate{ + ref: r, + scope: scope, + }) + } + + remoteScope, err := header.ScopeForIPv6Address(remoteAddr) + if err != nil { + // primaryIPv6Endpoint should never be called with an invalid IPv6 address. + log.Fatalf("header.ScopeForIPv6Address(%s): %s", remoteAddr, err) + } + + // Sort the addresses as per RFC 6724 section 5 rules 1-3. + // + // TODO(b/146021396): Implement rules 4-8 of RFC 6724 section 5. + sort.Slice(cs, func(i, j int) bool { + sa := cs[i] + sb := cs[j] + + // Prefer same address as per RFC 6724 section 5 rule 1. + if sa.ref.ep.ID().LocalAddress == remoteAddr { + return true + } + if sb.ref.ep.ID().LocalAddress == remoteAddr { + return false + } + + // Prefer appropriate scope as per RFC 6724 section 5 rule 2. + if sa.scope < sb.scope { + return sa.scope >= remoteScope + } else if sb.scope < sa.scope { + return sb.scope < remoteScope + } + + // Avoid deprecated addresses as per RFC 6724 section 5 rule 3. + if saDep, sbDep := sa.ref.deprecated, sb.ref.deprecated; saDep != sbDep { + // If sa is not deprecated, it is preferred over sb. + return sbDep + } + + // sa and sb are equal, return the endpoint that is closest to the front of + // the primary endpoint list. + return i < j + }) + + // Return the most preferred address that can have its reference count + // incremented. + for _, c := range cs { + if r := c.ref; r.tryIncRef() { + return r + } + } + + return nil +} + // hasPermanentAddrLocked returns true if n has a permanent (including currently // tentative) address, addr. func (n *NIC) hasPermanentAddrLocked(addr tcpip.Address) bool { diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go index 113b457fb..f8d89248e 100644 --- a/pkg/tcpip/stack/stack.go +++ b/pkg/tcpip/stack/stack.go @@ -1106,9 +1106,9 @@ func (s *Stack) GetMainNICAddress(id tcpip.NICID, protocol tcpip.NetworkProtocol return nic.primaryAddress(protocol), nil } -func (s *Stack) getRefEP(nic *NIC, localAddr tcpip.Address, netProto tcpip.NetworkProtocolNumber) (ref *referencedNetworkEndpoint) { +func (s *Stack) getRefEP(nic *NIC, localAddr, remoteAddr tcpip.Address, netProto tcpip.NetworkProtocolNumber) (ref *referencedNetworkEndpoint) { if len(localAddr) == 0 { - return nic.primaryEndpoint(netProto) + return nic.primaryEndpoint(netProto, remoteAddr) } return nic.findEndpoint(netProto, localAddr, CanBePrimaryEndpoint) } @@ -1124,7 +1124,7 @@ func (s *Stack) FindRoute(id tcpip.NICID, localAddr, remoteAddr tcpip.Address, n needRoute := !(isBroadcast || isMulticast || header.IsV6LinkLocalAddress(remoteAddr)) if id != 0 && !needRoute { if nic, ok := s.nics[id]; ok { - if ref := s.getRefEP(nic, localAddr, netProto); ref != nil { + if ref := s.getRefEP(nic, localAddr, remoteAddr, netProto); ref != nil { return makeRoute(netProto, ref.ep.ID().LocalAddress, remoteAddr, nic.linkEP.LinkAddress(), ref, s.handleLocal && !nic.isLoopback(), multicastLoop && !nic.isLoopback()), nil } } @@ -1134,7 +1134,7 @@ func (s *Stack) FindRoute(id tcpip.NICID, localAddr, remoteAddr tcpip.Address, n continue } if nic, ok := s.nics[route.NIC]; ok { - if ref := s.getRefEP(nic, localAddr, netProto); ref != nil { + if ref := s.getRefEP(nic, localAddr, remoteAddr, netProto); ref != nil { if len(remoteAddr) == 0 { // If no remote address was provided, then the route // provided will refer to the link local address. diff --git a/pkg/tcpip/stack/stack_test.go b/pkg/tcpip/stack/stack_test.go index 44e5229cc..4b3d18f1b 100644 --- a/pkg/tcpip/stack/stack_test.go +++ b/pkg/tcpip/stack/stack_test.go @@ -35,6 +35,7 @@ import ( "gvisor.dev/gvisor/pkg/tcpip/link/loopback" "gvisor.dev/gvisor/pkg/tcpip/network/ipv6" "gvisor.dev/gvisor/pkg/tcpip/stack" + "gvisor.dev/gvisor/pkg/tcpip/transport/udp" ) const ( @@ -2411,3 +2412,154 @@ func TestNewPEBOnPromotionToPermanent(t *testing.T) { } } } + +func TestIPv6SourceAddressSelectionScopeAndSameAddress(t *testing.T) { + const ( + linkLocalAddr1 = tcpip.Address("\xfe\x80\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01") + linkLocalAddr2 = tcpip.Address("\xfe\x80\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02") + uniqueLocalAddr1 = tcpip.Address("\xfc\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01") + uniqueLocalAddr2 = tcpip.Address("\xfd\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02") + 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 + ) + + // 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 + }{ + // Test Rule 1 of RFC 6724 section 5. + { + name: "Same Global most preferred (last address)", + nicAddrs: []tcpip.Address{linkLocalAddr1, uniqueLocalAddr1, globalAddr1}, + connectAddr: globalAddr1, + expectedLocalAddr: globalAddr1, + }, + { + name: "Same Global most preferred (first address)", + nicAddrs: []tcpip.Address{globalAddr1, linkLocalAddr1, uniqueLocalAddr1}, + connectAddr: globalAddr1, + expectedLocalAddr: globalAddr1, + }, + { + name: "Same Link Local most preferred (last address)", + nicAddrs: []tcpip.Address{globalAddr1, uniqueLocalAddr1, linkLocalAddr1}, + connectAddr: linkLocalAddr1, + expectedLocalAddr: linkLocalAddr1, + }, + { + name: "Same Link Local most preferred (first address)", + nicAddrs: []tcpip.Address{linkLocalAddr1, uniqueLocalAddr1, globalAddr1}, + connectAddr: linkLocalAddr1, + expectedLocalAddr: linkLocalAddr1, + }, + { + name: "Same Unique Local most preferred (last address)", + nicAddrs: []tcpip.Address{uniqueLocalAddr1, globalAddr1, linkLocalAddr1}, + connectAddr: uniqueLocalAddr1, + expectedLocalAddr: uniqueLocalAddr1, + }, + { + name: "Same Unique Local most preferred (first address)", + nicAddrs: []tcpip.Address{globalAddr1, linkLocalAddr1, uniqueLocalAddr1}, + connectAddr: uniqueLocalAddr1, + expectedLocalAddr: uniqueLocalAddr1, + }, + + // Test Rule 2 of RFC 6724 section 5. + { + name: "Global most preferred (last address)", + nicAddrs: []tcpip.Address{linkLocalAddr1, uniqueLocalAddr1, globalAddr1}, + connectAddr: globalAddr2, + expectedLocalAddr: globalAddr1, + }, + { + name: "Global most preferred (first address)", + nicAddrs: []tcpip.Address{globalAddr1, linkLocalAddr1, uniqueLocalAddr1}, + connectAddr: globalAddr2, + expectedLocalAddr: globalAddr1, + }, + { + name: "Link Local most preferred (last address)", + nicAddrs: []tcpip.Address{globalAddr1, uniqueLocalAddr1, linkLocalAddr1}, + connectAddr: linkLocalAddr2, + expectedLocalAddr: linkLocalAddr1, + }, + { + name: "Link Local most preferred (first address)", + nicAddrs: []tcpip.Address{linkLocalAddr1, uniqueLocalAddr1, globalAddr1}, + connectAddr: linkLocalAddr2, + expectedLocalAddr: linkLocalAddr1, + }, + { + name: "Unique Local most preferred (last address)", + nicAddrs: []tcpip.Address{uniqueLocalAddr1, globalAddr1, linkLocalAddr1}, + connectAddr: uniqueLocalAddr2, + expectedLocalAddr: uniqueLocalAddr1, + }, + { + name: "Unique Local most preferred (first address)", + nicAddrs: []tcpip.Address{globalAddr1, linkLocalAddr1, uniqueLocalAddr1}, + connectAddr: uniqueLocalAddr2, + expectedLocalAddr: uniqueLocalAddr1, + }, + + // Test returning the endpoint that is closest to the front when + // candidate addresses are "equal" from the perspective of RFC 6724 + // section 5. + { + name: "Unique Local for Global", + nicAddrs: []tcpip.Address{linkLocalAddr1, uniqueLocalAddr1, uniqueLocalAddr2}, + connectAddr: globalAddr2, + expectedLocalAddr: uniqueLocalAddr1, + }, + { + name: "Link Local for Global", + nicAddrs: []tcpip.Address{linkLocalAddr1, linkLocalAddr2}, + connectAddr: globalAddr2, + expectedLocalAddr: linkLocalAddr1, + }, + { + name: "Link Local for Unique Local", + nicAddrs: []tcpip.Address{linkLocalAddr1, linkLocalAddr2}, + connectAddr: uniqueLocalAddr2, + expectedLocalAddr: linkLocalAddr1, + }, + } + + for _, test := range tests { + t.Run(test.name, func(t *testing.T) { + e := channel.New(0, 1280, linkAddr1) + s := stack.New(stack.Options{ + NetworkProtocols: []stack.NetworkProtocol{ipv6.NewProtocol()}, + TransportProtocols: []stack.TransportProtocol{udp.NewProtocol()}, + }) + if err := s.CreateNIC(nicID, e); err != nil { + t.Fatalf("CreateNIC(%d, _) = %s", nicID, err) + } + s.SetRouteTable([]tcpip.Route{{ + Destination: header.IPv6EmptySubnet, + Gateway: llAddr3, + NIC: nicID, + }}) + s.AddLinkAddress(nicID, llAddr3, linkAddr3) + + 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 t.Failed() { + t.FailNow() + } + + if got := addrForNewConnectionTo(t, s, tcpip.FullAddress{Addr: test.connectAddr, NIC: nicID, Port: 1234}); got != test.expectedLocalAddr { + t.Errorf("got local address = %s, want = %s", got, test.expectedLocalAddr) + } + }) + } +} -- cgit v1.2.3 From 50625cee59aaff834c7968771ab385ad0e7b0e1f Mon Sep 17 00:00:00 2001 From: Tamir Duberstein Date: Tue, 14 Jan 2020 13:31:52 -0800 Subject: Implement {g,s}etsockopt(IP_RECVTOS) for UDP sockets PiperOrigin-RevId: 289718534 --- pkg/sentry/socket/control/control.go | 2 +- pkg/sentry/socket/netstack/netstack.go | 36 +++++++++++++-- pkg/tcpip/checker/checker.go | 16 +++++++ pkg/tcpip/stack/nic.go | 2 +- pkg/tcpip/stack/stack.go | 2 +- pkg/tcpip/tcpip.go | 8 +++- pkg/tcpip/transport/udp/endpoint.go | 40 +++++++++++++++-- pkg/tcpip/transport/udp/udp_test.go | 67 ++++++++++++++++++++++++---- test/syscalls/linux/socket_ip_udp_generic.cc | 40 +++++++++++++++++ test/syscalls/linux/udp_socket_test_cases.cc | 8 ++-- 10 files changed, 197 insertions(+), 24 deletions(-) (limited to 'pkg/tcpip/stack/stack.go') diff --git a/pkg/sentry/socket/control/control.go b/pkg/sentry/socket/control/control.go index 4301b697c..1684dfc24 100644 --- a/pkg/sentry/socket/control/control.go +++ b/pkg/sentry/socket/control/control.go @@ -327,7 +327,7 @@ func PackInq(t *kernel.Task, inq int32, buf []byte) []byte { } // PackTOS packs an IP_TOS socket control message. -func PackTOS(t *kernel.Task, tos int8, buf []byte) []byte { +func PackTOS(t *kernel.Task, tos uint8, buf []byte) []byte { return putCmsgStruct( buf, linux.SOL_IP, diff --git a/pkg/sentry/socket/netstack/netstack.go b/pkg/sentry/socket/netstack/netstack.go index c020c11cb..d2f7e987d 100644 --- a/pkg/sentry/socket/netstack/netstack.go +++ b/pkg/sentry/socket/netstack/netstack.go @@ -1268,11 +1268,11 @@ func getSockOptIPv6(t *kernel.Task, ep commonEndpoint, name, outLen int) (interf if err != nil { return nil, syserr.TranslateNetstackError(err) } - var o uint32 + var o int32 if v { o = 1 } - return int32(o), nil + return o, nil case linux.IPV6_PATHMTU: t.Kernel().EmitUnimplementedEvent(t) @@ -1377,6 +1377,21 @@ func getSockOptIP(t *kernel.Task, ep commonEndpoint, name, outLen int, family in } return int32(v), nil + case linux.IP_RECVTOS: + if outLen < sizeOfInt32 { + return nil, syserr.ErrInvalidArgument + } + + v, err := ep.GetSockOptBool(tcpip.ReceiveTOSOption) + if err != nil { + return nil, syserr.TranslateNetstackError(err) + } + var o int32 + if v { + o = 1 + } + return o, nil + default: emitUnimplementedEventIP(t, name) } @@ -1895,6 +1910,13 @@ func setSockOptIP(t *kernel.Task, ep commonEndpoint, name int, optVal []byte) *s } return syserr.TranslateNetstackError(ep.SetSockOpt(tcpip.IPv4TOSOption(v))) + case linux.IP_RECVTOS: + v, err := parseIntOrChar(optVal) + if err != nil { + return err + } + return syserr.TranslateNetstackError(ep.SetSockOptBool(tcpip.ReceiveTOSOption, v != 0)) + case linux.IP_ADD_SOURCE_MEMBERSHIP, linux.IP_BIND_ADDRESS_NO_PORT, linux.IP_BLOCK_SOURCE, @@ -1915,7 +1937,6 @@ func setSockOptIP(t *kernel.Task, ep commonEndpoint, name int, optVal []byte) *s linux.IP_RECVFRAGSIZE, linux.IP_RECVOPTS, linux.IP_RECVORIGDSTADDR, - linux.IP_RECVTOS, linux.IP_RECVTTL, linux.IP_RETOPTS, linux.IP_TRANSPARENT, @@ -2335,7 +2356,14 @@ func (s *SocketOperations) nonBlockingRead(ctx context.Context, dst usermem.IOSe } func (s *SocketOperations) controlMessages() socket.ControlMessages { - return socket.ControlMessages{IP: tcpip.ControlMessages{HasTimestamp: s.readCM.HasTimestamp && s.sockOptTimestamp, Timestamp: s.readCM.Timestamp}} + return socket.ControlMessages{ + IP: tcpip.ControlMessages{ + HasTimestamp: s.readCM.HasTimestamp && s.sockOptTimestamp, + Timestamp: s.readCM.Timestamp, + HasTOS: s.readCM.HasTOS, + TOS: s.readCM.TOS, + }, + } } // updateTimestamp sets the timestamp for SIOCGSTAMP. It should be called after diff --git a/pkg/tcpip/checker/checker.go b/pkg/tcpip/checker/checker.go index 2f15bf1f1..542abc99d 100644 --- a/pkg/tcpip/checker/checker.go +++ b/pkg/tcpip/checker/checker.go @@ -33,6 +33,9 @@ type NetworkChecker func(*testing.T, []header.Network) // TransportChecker is a function to check a property of a transport packet. type TransportChecker func(*testing.T, header.Transport) +// ControlMessagesChecker is a function to check a property of ancillary data. +type ControlMessagesChecker func(*testing.T, tcpip.ControlMessages) + // IPv4 checks the validity and properties of the given IPv4 packet. It is // expected to be used in conjunction with other network checkers for specific // properties. For example, to check the source and destination address, one @@ -158,6 +161,19 @@ func FragmentFlags(flags uint8) NetworkChecker { } } +// ReceiveTOS creates a checker that checks the TOS field in ControlMessages. +func ReceiveTOS(want uint8) ControlMessagesChecker { + return func(t *testing.T, cm tcpip.ControlMessages) { + t.Helper() + if !cm.HasTOS { + t.Fatalf("got cm.HasTOS = %t, want cm.TOS = %d", cm.HasTOS, want) + } + if got := cm.TOS; got != want { + t.Fatalf("got cm.TOS = %d, want %d", got, want) + } + } +} + // TOS creates a checker that checks the TOS field. func TOS(tos uint8, label uint32) NetworkChecker { return func(t *testing.T, h []header.Network) { diff --git a/pkg/tcpip/stack/nic.go b/pkg/tcpip/stack/nic.go index abf73fe33..071221d5a 100644 --- a/pkg/tcpip/stack/nic.go +++ b/pkg/tcpip/stack/nic.go @@ -763,7 +763,7 @@ func (n *NIC) RemoveAddressRange(subnet tcpip.Subnet) { n.mu.Unlock() } -// Subnets returns the Subnets associated with this NIC. +// AddressRanges returns the Subnets associated with this NIC. func (n *NIC) AddressRanges() []tcpip.Subnet { n.mu.RLock() defer n.mu.RUnlock() diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go index f8d89248e..386eb6eec 100644 --- a/pkg/tcpip/stack/stack.go +++ b/pkg/tcpip/stack/stack.go @@ -912,7 +912,7 @@ func (s *Stack) CheckNIC(id tcpip.NICID) bool { return false } -// NICSubnets returns a map of NICIDs to their associated subnets. +// NICAddressRanges returns a map of NICIDs to their associated subnets. func (s *Stack) NICAddressRanges() map[tcpip.NICID][]tcpip.Subnet { s.mu.RLock() defer s.mu.RUnlock() diff --git a/pkg/tcpip/tcpip.go b/pkg/tcpip/tcpip.go index 4a090ac86..b7813cbc0 100644 --- a/pkg/tcpip/tcpip.go +++ b/pkg/tcpip/tcpip.go @@ -322,7 +322,7 @@ type ControlMessages struct { HasTOS bool // TOS is the IPv4 type of service of the associated packet. - TOS int8 + TOS uint8 // HasTClass indicates whether Tclass is valid/set. HasTClass bool @@ -500,9 +500,13 @@ type WriteOptions struct { type SockOptBool int const ( + // ReceiveTOSOption is used by SetSockOpt/GetSockOpt to specify if the TOS + // ancillary message is passed with incoming packets. + ReceiveTOSOption SockOptBool = iota + // V6OnlyOption is used by {G,S}etSockOptBool to specify whether an IPv6 // socket is to be restricted to sending and receiving IPv6 packets only. - V6OnlyOption SockOptBool = iota + V6OnlyOption ) // SockOptInt represents socket options which values have the int type. diff --git a/pkg/tcpip/transport/udp/endpoint.go b/pkg/tcpip/transport/udp/endpoint.go index 13446f5d9..c9cbed8f4 100644 --- a/pkg/tcpip/transport/udp/endpoint.go +++ b/pkg/tcpip/transport/udp/endpoint.go @@ -31,6 +31,7 @@ type udpPacket struct { senderAddress tcpip.FullAddress data buffer.VectorisedView `state:".(buffer.VectorisedView)"` timestamp int64 + tos uint8 } // EndpointState represents the state of a UDP endpoint. @@ -113,6 +114,10 @@ type endpoint struct { // applied while sending packets. Defaults to 0 as on Linux. sendTOS uint8 + // receiveTOS determines if the incoming IPv4 TOS header field is passed + // as ancillary data to ControlMessages on Read. + receiveTOS bool + // shutdownFlags represent the current shutdown state of the endpoint. shutdownFlags tcpip.ShutdownFlags @@ -243,7 +248,18 @@ func (e *endpoint) Read(addr *tcpip.FullAddress) (buffer.View, tcpip.ControlMess *addr = p.senderAddress } - return p.data.ToView(), tcpip.ControlMessages{HasTimestamp: true, Timestamp: p.timestamp}, nil + cm := tcpip.ControlMessages{ + HasTimestamp: true, + Timestamp: p.timestamp, + } + e.mu.RLock() + receiveTOS := e.receiveTOS + e.mu.RUnlock() + if receiveTOS { + cm.HasTOS = true + cm.TOS = p.tos + } + return p.data.ToView(), cm, nil } // prepareForWrite prepares the endpoint for sending data. In particular, it @@ -458,6 +474,12 @@ func (e *endpoint) Peek([][]byte) (int64, tcpip.ControlMessages, *tcpip.Error) { // SetSockOptBool implements tcpip.Endpoint.SetSockOptBool. func (e *endpoint) SetSockOptBool(opt tcpip.SockOptBool, v bool) *tcpip.Error { switch opt { + case tcpip.ReceiveTOSOption: + e.mu.Lock() + e.receiveTOS = v + e.mu.Unlock() + return nil + case tcpip.V6OnlyOption: // We only recognize this option on v6 endpoints. if e.NetProto != header.IPv6ProtocolNumber { @@ -664,15 +686,21 @@ func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error { // GetSockOptBool implements tcpip.Endpoint.GetSockOptBool. func (e *endpoint) GetSockOptBool(opt tcpip.SockOptBool) (bool, *tcpip.Error) { switch opt { + case tcpip.ReceiveTOSOption: + e.mu.RLock() + v := e.receiveTOS + e.mu.RUnlock() + return v, nil + case tcpip.V6OnlyOption: // We only recognize this option on v6 endpoints. if e.NetProto != header.IPv6ProtocolNumber { return false, tcpip.ErrUnknownProtocolOption } - e.mu.Lock() + e.mu.RLock() v := e.v6only - e.mu.Unlock() + e.mu.RUnlock() return v, nil } @@ -1215,6 +1243,12 @@ func (e *endpoint) HandlePacket(r *stack.Route, id stack.TransportEndpointID, pk e.rcvList.PushBack(packet) e.rcvBufSize += pkt.Data.Size() + // Save any useful information from the network header to the packet. + switch r.NetProto { + case header.IPv4ProtocolNumber: + packet.tos, _ = header.IPv4(pkt.NetworkHeader).TOS() + } + packet.timestamp = e.stack.NowNanoseconds() e.rcvMu.Unlock() diff --git a/pkg/tcpip/transport/udp/udp_test.go b/pkg/tcpip/transport/udp/udp_test.go index 0a82bc4fa..ee9d10555 100644 --- a/pkg/tcpip/transport/udp/udp_test.go +++ b/pkg/tcpip/transport/udp/udp_test.go @@ -56,6 +56,7 @@ const ( multicastAddr = "\xe8\x2b\xd3\xea" multicastV6Addr = "\xff\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" broadcastAddr = header.IPv4Broadcast + testTOS = 0x80 // defaultMTU is the MTU, in bytes, used throughout the tests, except // where another value is explicitly used. It is chosen to match the MTU @@ -453,6 +454,7 @@ func (c *testContext) injectV4Packet(payload []byte, h *header4Tuple, valid bool ip := header.IPv4(buf) ip.Encode(&header.IPv4Fields{ IHL: header.IPv4MinimumSize, + TOS: testTOS, TotalLength: uint16(len(buf)), TTL: 65, Protocol: uint8(udp.ProtocolNumber), @@ -552,8 +554,8 @@ func TestBindToDeviceOption(t *testing.T) { // testReadInternal sends a packet of the given test flow into the stack by // injecting it into the link endpoint. It then attempts to read it from the // UDP endpoint and depending on if this was expected to succeed verifies its -// correctness. -func testReadInternal(c *testContext, flow testFlow, packetShouldBeDropped, expectReadError bool) { +// correctness including any additional checker functions provided. +func testReadInternal(c *testContext, flow testFlow, packetShouldBeDropped, expectReadError bool, checkers ...checker.ControlMessagesChecker) { c.t.Helper() payload := newPayload() @@ -568,12 +570,12 @@ func testReadInternal(c *testContext, flow testFlow, packetShouldBeDropped, expe epstats := c.ep.Stats().(*tcpip.TransportEndpointStats).Clone() var addr tcpip.FullAddress - v, _, err := c.ep.Read(&addr) + v, cm, err := c.ep.Read(&addr) if err == tcpip.ErrWouldBlock { // Wait for data to become available. select { case <-ch: - v, _, err = c.ep.Read(&addr) + v, cm, err = c.ep.Read(&addr) case <-time.After(300 * time.Millisecond): if packetShouldBeDropped { @@ -606,15 +608,21 @@ func testReadInternal(c *testContext, flow testFlow, packetShouldBeDropped, expe if !bytes.Equal(payload, v) { c.t.Fatalf("bad payload: got %x, want %x", v, payload) } + + // Run any checkers against the ControlMessages. + for _, f := range checkers { + f(c.t, cm) + } + c.checkEndpointReadStats(1, epstats, err) } // testRead sends a packet of the given test flow into the stack by injecting it // into the link endpoint. It then reads it from the UDP endpoint and verifies -// its correctness. -func testRead(c *testContext, flow testFlow) { +// its correctness including any additional checker functions provided. +func testRead(c *testContext, flow testFlow, checkers ...checker.ControlMessagesChecker) { c.t.Helper() - testReadInternal(c, flow, false /* packetShouldBeDropped */, false /* expectReadError */) + testReadInternal(c, flow, false /* packetShouldBeDropped */, false /* expectReadError */, checkers...) } // testFailingRead sends a packet of the given test flow into the stack by @@ -1282,7 +1290,7 @@ func TestTOSV4(t *testing.T) { c.createEndpointForFlow(flow) - const tos = 0xC0 + const tos = testTOS var v tcpip.IPv4TOSOption if err := c.ep.GetSockOpt(&v); err != nil { c.t.Errorf("GetSockopt failed: %s", err) @@ -1317,7 +1325,7 @@ func TestTOSV6(t *testing.T) { c.createEndpointForFlow(flow) - const tos = 0xC0 + const tos = testTOS var v tcpip.IPv6TrafficClassOption if err := c.ep.GetSockOpt(&v); err != nil { c.t.Errorf("GetSockopt failed: %s", err) @@ -1344,6 +1352,47 @@ func TestTOSV6(t *testing.T) { } } +func TestReceiveTOSV4(t *testing.T) { + for _, flow := range []testFlow{unicastV4, broadcast} { + t.Run(fmt.Sprintf("flow:%s", flow), func(t *testing.T) { + c := newDualTestContext(t, defaultMTU) + defer c.cleanup() + + c.createEndpointForFlow(flow) + + // Verify that setting and reading the option works. + v, err := c.ep.GetSockOptBool(tcpip.ReceiveTOSOption) + if err != nil { + c.t.Fatal("GetSockOptBool(tcpip.ReceiveTOSOption) failed:", err) + } + // Test for expected default value. + if v != false { + c.t.Errorf("got GetSockOptBool(tcpip.ReceiveTOSOption) = %t, want = %t", v, false) + } + + want := true + if err := c.ep.SetSockOptBool(tcpip.ReceiveTOSOption, want); err != nil { + c.t.Fatalf("SetSockOptBool(tcpip.ReceiveTOSOption, %t) failed: %s", want, err) + } + + got, err := c.ep.GetSockOptBool(tcpip.ReceiveTOSOption) + if err != nil { + c.t.Fatal("GetSockOptBool(tcpip.ReceiveTOSOption) failed:", err) + } + if got != want { + c.t.Fatalf("got GetSockOptBool(tcpip.ReceiveTOSOption) = %t, want = %t", got, want) + } + + // Verify that the correct received TOS is handed through as + // ancillary data to the ControlMessages struct. + if err := c.ep.Bind(tcpip.FullAddress{Port: stackPort}); err != nil { + c.t.Fatal("Bind failed:", err) + } + testRead(c, flow, checker.ReceiveTOS(testTOS)) + }) + } +} + func TestMulticastInterfaceOption(t *testing.T) { for _, flow := range []testFlow{multicastV4, multicastV4in6, multicastV6, multicastV6Only} { t.Run(fmt.Sprintf("flow:%s", flow), func(t *testing.T) { diff --git a/test/syscalls/linux/socket_ip_udp_generic.cc b/test/syscalls/linux/socket_ip_udp_generic.cc index 66eb68857..53290bed7 100644 --- a/test/syscalls/linux/socket_ip_udp_generic.cc +++ b/test/syscalls/linux/socket_ip_udp_generic.cc @@ -209,6 +209,46 @@ TEST_P(UDPSocketPairTest, SetMulticastLoopChar) { EXPECT_EQ(get, kSockOptOn); } +// Ensure that Receiving TOS is off by default. +TEST_P(UDPSocketPairTest, RecvTosDefault) { + auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair()); + + int get = -1; + socklen_t get_len = sizeof(get); + ASSERT_THAT( + getsockopt(sockets->first_fd(), IPPROTO_IP, IP_RECVTOS, &get, &get_len), + SyscallSucceedsWithValue(0)); + EXPECT_EQ(get_len, sizeof(get)); + EXPECT_EQ(get, kSockOptOff); +} + +// Test that setting and getting IP_RECVTOS works as expected. +TEST_P(UDPSocketPairTest, SetRecvTos) { + auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair()); + + ASSERT_THAT(setsockopt(sockets->first_fd(), IPPROTO_IP, IP_RECVTOS, + &kSockOptOff, sizeof(kSockOptOff)), + SyscallSucceeds()); + + int get = -1; + socklen_t get_len = sizeof(get); + ASSERT_THAT( + getsockopt(sockets->first_fd(), IPPROTO_IP, IP_RECVTOS, &get, &get_len), + SyscallSucceedsWithValue(0)); + EXPECT_EQ(get_len, sizeof(get)); + EXPECT_EQ(get, kSockOptOff); + + ASSERT_THAT(setsockopt(sockets->first_fd(), IPPROTO_IP, IP_RECVTOS, + &kSockOptOn, sizeof(kSockOptOn)), + SyscallSucceeds()); + + ASSERT_THAT( + getsockopt(sockets->first_fd(), IPPROTO_IP, IP_RECVTOS, &get, &get_len), + SyscallSucceedsWithValue(0)); + EXPECT_EQ(get_len, sizeof(get)); + EXPECT_EQ(get, kSockOptOn); +} + TEST_P(UDPSocketPairTest, ReuseAddrDefault) { auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair()); diff --git a/test/syscalls/linux/udp_socket_test_cases.cc b/test/syscalls/linux/udp_socket_test_cases.cc index dc35c2f50..68e0a8109 100644 --- a/test/syscalls/linux/udp_socket_test_cases.cc +++ b/test/syscalls/linux/udp_socket_test_cases.cc @@ -1349,8 +1349,9 @@ TEST_P(UdpSocketTest, TimestampIoctlPersistence) { // outgoing packets, and that a receiving socket with IP_RECVTOS or // IPV6_RECVTCLASS will create the corresponding control message. TEST_P(UdpSocketTest, SetAndReceiveTOS) { - // TODO(b/68320120): IP_RECVTOS/IPV6_RECVTCLASS not supported for netstack. - SKIP_IF(IsRunningOnGvisor() && !IsRunningWithHostinet()); + // TODO(b/68320120): IPV6_RECVTCLASS not supported for netstack. + SKIP_IF((GetParam() != AddressFamily::kIpv4) && IsRunningOnGvisor() && + !IsRunningWithHostinet()); ASSERT_THAT(bind(s_, addr_[0], addrlen_), SyscallSucceeds()); ASSERT_THAT(connect(t_, addr_[0], addrlen_), SyscallSucceeds()); @@ -1421,7 +1422,8 @@ TEST_P(UdpSocketTest, SetAndReceiveTOS) { // TOS byte on outgoing packets, and that a receiving socket with IP_RECVTOS or // IPV6_RECVTCLASS will create the corresponding control message. TEST_P(UdpSocketTest, SendAndReceiveTOS) { - // TODO(b/68320120): IP_RECVTOS/IPV6_RECVTCLASS not supported for netstack. + // TODO(b/68320120): IPV6_RECVTCLASS not supported for netstack. + // TODO(b/146661005): Setting TOS via cmsg not supported for netstack. SKIP_IF(IsRunningOnGvisor() && !IsRunningWithHostinet()); ASSERT_THAT(bind(s_, addr_[0], addrlen_), SyscallSucceeds()); ASSERT_THAT(connect(t_, addr_[0], addrlen_), SyscallSucceeds()); -- cgit v1.2.3 From 815df2959a76e4a19f5882e40402b9bbca9e70be Mon Sep 17 00:00:00 2001 From: Ghanan Gowripalan Date: Wed, 15 Jan 2020 16:43:36 -0800 Subject: Solicit IPv6 routers when a NIC becomes enabled as a host This change adds support to send NDP Router Solicitation messages when a NIC becomes enabled as a host, as per RFC 4861 section 6.3.7. Note, Router Solicitations will only be sent when the stack has forwarding disabled. Tests: Unittests to make sure that the initial Router Solicitations are sent as configured. The tests also validate the sent Router Solicitations' fields. PiperOrigin-RevId: 289964095 --- pkg/tcpip/checker/checker.go | 6 + pkg/tcpip/header/BUILD | 1 + pkg/tcpip/header/ipv6.go | 7 ++ pkg/tcpip/header/ndp_router_solicit.go | 36 ++++++ pkg/tcpip/stack/BUILD | 2 +- pkg/tcpip/stack/ndp.go | 175 +++++++++++++++++++++++--- pkg/tcpip/stack/ndp_test.go | 224 +++++++++++++++++++++++++++++++++ pkg/tcpip/stack/nic.go | 73 +++++++---- pkg/tcpip/stack/stack.go | 8 +- 9 files changed, 486 insertions(+), 46 deletions(-) create mode 100644 pkg/tcpip/header/ndp_router_solicit.go (limited to 'pkg/tcpip/stack/stack.go') 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() + } } } -- cgit v1.2.3