diff options
-rw-r--r-- | pkg/tcpip/network/ipv4/icmp.go | 20 | ||||
-rw-r--r-- | pkg/tcpip/network/ipv6/icmp.go | 20 | ||||
-rw-r--r-- | pkg/tcpip/stack/BUILD | 1 | ||||
-rw-r--r-- | pkg/tcpip/stack/route.go | 24 | ||||
-rw-r--r-- | pkg/tcpip/stack/stack_test.go | 48 | ||||
-rw-r--r-- | pkg/tcpip/tests/integration/BUILD | 1 | ||||
-rw-r--r-- | pkg/tcpip/tests/integration/multicast_broadcast_test.go | 208 | ||||
-rw-r--r-- | pkg/tcpip/transport/udp/endpoint.go | 2 |
8 files changed, 299 insertions, 25 deletions
diff --git a/pkg/tcpip/network/ipv4/icmp.go b/pkg/tcpip/network/ipv4/icmp.go index 83e71cb8c..94803a359 100644 --- a/pkg/tcpip/network/ipv4/icmp.go +++ b/pkg/tcpip/network/ipv4/icmp.go @@ -96,6 +96,26 @@ func (e *endpoint) handleICMP(r *stack.Route, pkt *stack.PacketBuffer) { NetworkHeader: append(buffer.View(nil), pkt.NetworkHeader...), }) + remoteLinkAddr := r.RemoteLinkAddress + + // As per RFC 1122 section 3.2.1.3, when a host sends any datagram, the IP + // source address MUST be one of its own IP addresses (but not a broadcast + // or multicast address). + localAddr := r.LocalAddress + if r.IsInboundBroadcast() || header.IsV4MulticastAddress(r.LocalAddress) { + localAddr = "" + } + + r, err := r.Stack().FindRoute(e.NICID(), localAddr, r.RemoteAddress, ProtocolNumber, false /* multicastLoop */) + if err != nil { + // If we cannot find a route to the destination, silently drop the packet. + return + } + defer r.Release() + + // Use the remote link address from the incoming packet. + r.ResolveWith(remoteLinkAddr) + vv := pkt.Data.Clone(nil) vv.TrimFront(header.ICMPv4MinimumSize) hdr := buffer.NewPrependable(int(r.MaxHeaderLength()) + header.ICMPv4MinimumSize) diff --git a/pkg/tcpip/network/ipv6/icmp.go b/pkg/tcpip/network/ipv6/icmp.go index 24600d877..ded91d83a 100644 --- a/pkg/tcpip/network/ipv6/icmp.go +++ b/pkg/tcpip/network/ipv6/icmp.go @@ -389,6 +389,26 @@ func (e *endpoint) handleICMP(r *stack.Route, pkt *stack.PacketBuffer, hasFragme received.Invalid.Increment() return } + + remoteLinkAddr := r.RemoteLinkAddress + + // As per RFC 4291 section 2.7, multicast addresses must not be used as + // source addresses in IPv6 packets. + localAddr := r.LocalAddress + if header.IsV6MulticastAddress(r.LocalAddress) { + localAddr = "" + } + + r, err := r.Stack().FindRoute(e.NICID(), localAddr, r.RemoteAddress, ProtocolNumber, false /* multicastLoop */) + if err != nil { + // If we cannot find a route to the destination, silently drop the packet. + return + } + defer r.Release() + + // Use the link address from the source of the original packet. + r.ResolveWith(remoteLinkAddr) + pkt.Data.TrimFront(header.ICMPv6EchoMinimumSize) hdr := buffer.NewPrependable(int(r.MaxHeaderLength()) + header.ICMPv6EchoMinimumSize) packet := header.ICMPv6(hdr.Prepend(header.ICMPv6EchoMinimumSize)) diff --git a/pkg/tcpip/stack/BUILD b/pkg/tcpip/stack/BUILD index 1c58bed2d..bfc7a0c7c 100644 --- a/pkg/tcpip/stack/BUILD +++ b/pkg/tcpip/stack/BUILD @@ -121,6 +121,7 @@ go_test( "//pkg/tcpip/header", "//pkg/tcpip/link/channel", "//pkg/tcpip/link/loopback", + "//pkg/tcpip/network/arp", "//pkg/tcpip/network/ipv4", "//pkg/tcpip/network/ipv6", "//pkg/tcpip/ports", diff --git a/pkg/tcpip/stack/route.go b/pkg/tcpip/stack/route.go index 91e0110f1..9ce0a2c22 100644 --- a/pkg/tcpip/stack/route.go +++ b/pkg/tcpip/stack/route.go @@ -110,6 +110,12 @@ func (r *Route) GSOMaxSize() uint32 { return 0 } +// ResolveWith immediately resolves a route with the specified remote link +// address. +func (r *Route) ResolveWith(addr tcpip.LinkAddress) { + r.RemoteLinkAddress = addr +} + // Resolve attempts to resolve the link address if necessary. Returns ErrWouldBlock in // case address resolution requires blocking, e.g. wait for ARP reply. Waker is // notified when address resolution is complete (success or not). @@ -279,12 +285,26 @@ func (r *Route) Stack() *Stack { return r.ref.stack() } -// IsBroadcast returns true if the route is to send a broadcast packet. -func (r *Route) IsBroadcast() bool { +// IsOutboundBroadcast returns true if the route is for an outbound broadcast +// packet. +func (r *Route) IsOutboundBroadcast() bool { // Only IPv4 has a notion of broadcast. return r.directedBroadcast || r.RemoteAddress == header.IPv4Broadcast } +// IsInboundBroadcast returns true if the route is for an inbound broadcast +// packet. +func (r *Route) IsInboundBroadcast() bool { + // Only IPv4 has a notion of broadcast. + if r.LocalAddress == header.IPv4Broadcast { + return true + } + + addr := r.ref.addrWithPrefix() + subnet := addr.Subnet() + return subnet.IsBroadcast(r.LocalAddress) +} + // ReverseRoute returns new route with given source and destination address. func (r *Route) ReverseRoute(src tcpip.Address, dst tcpip.Address) Route { return Route{ diff --git a/pkg/tcpip/stack/stack_test.go b/pkg/tcpip/stack/stack_test.go index 0b6deda02..fe1c1b8a4 100644 --- a/pkg/tcpip/stack/stack_test.go +++ b/pkg/tcpip/stack/stack_test.go @@ -21,6 +21,7 @@ import ( "bytes" "fmt" "math" + "net" "sort" "strings" "testing" @@ -34,6 +35,7 @@ import ( "gvisor.dev/gvisor/pkg/tcpip/header" "gvisor.dev/gvisor/pkg/tcpip/link/channel" "gvisor.dev/gvisor/pkg/tcpip/link/loopback" + "gvisor.dev/gvisor/pkg/tcpip/network/arp" "gvisor.dev/gvisor/pkg/tcpip/network/ipv4" "gvisor.dev/gvisor/pkg/tcpip/network/ipv6" "gvisor.dev/gvisor/pkg/tcpip/stack" @@ -3694,3 +3696,49 @@ func TestOutgoingSubnetBroadcast(t *testing.T) { }) } } + +func TestResolveWith(t *testing.T) { + const ( + unspecifiedNICID = 0 + nicID = 1 + ) + + s := stack.New(stack.Options{ + NetworkProtocols: []stack.NetworkProtocol{ipv4.NewProtocol(), arp.NewProtocol()}, + }) + ep := channel.New(0, defaultMTU, "") + ep.LinkEPCapabilities |= stack.CapabilityResolutionRequired + if err := s.CreateNIC(nicID, ep); err != nil { + t.Fatalf("CreateNIC(%d, _): %s", nicID, err) + } + addr := tcpip.ProtocolAddress{ + Protocol: header.IPv4ProtocolNumber, + AddressWithPrefix: tcpip.AddressWithPrefix{ + Address: tcpip.Address(net.ParseIP("192.168.1.58").To4()), + PrefixLen: 24, + }, + } + if err := s.AddProtocolAddress(nicID, addr); err != nil { + t.Fatalf("AddProtocolAddress(%d, %+v): %s", nicID, addr, err) + } + + s.SetRouteTable([]tcpip.Route{{Destination: header.IPv4EmptySubnet, NIC: nicID}}) + + remoteAddr := tcpip.Address(net.ParseIP("192.168.1.59").To4()) + r, err := s.FindRoute(unspecifiedNICID, "" /* localAddr */, remoteAddr, header.IPv4ProtocolNumber, false /* multicastLoop */) + if err != nil { + t.Fatalf("FindRoute(%d, '', %s, %d): %s", unspecifiedNICID, remoteAddr, header.IPv4ProtocolNumber, err) + } + defer r.Release() + + // Should initially require resolution. + if !r.IsResolutionRequired() { + t.Fatal("got r.IsResolutionRequired() = false, want = true") + } + + // Manually resolving the route should no longer require resolution. + r.ResolveWith("\x01") + if r.IsResolutionRequired() { + t.Fatal("got r.IsResolutionRequired() = true, want = false") + } +} diff --git a/pkg/tcpip/tests/integration/BUILD b/pkg/tcpip/tests/integration/BUILD index 7fff30462..6d52af98a 100644 --- a/pkg/tcpip/tests/integration/BUILD +++ b/pkg/tcpip/tests/integration/BUILD @@ -14,6 +14,7 @@ go_test( "//pkg/tcpip/network/ipv4", "//pkg/tcpip/network/ipv6", "//pkg/tcpip/stack", + "//pkg/tcpip/transport/icmp", "//pkg/tcpip/transport/udp", "//pkg/waiter", "@com_github_google_go_cmp//cmp:go_default_library", diff --git a/pkg/tcpip/tests/integration/multicast_broadcast_test.go b/pkg/tcpip/tests/integration/multicast_broadcast_test.go index d9b2d147a..0ff3a2b89 100644 --- a/pkg/tcpip/tests/integration/multicast_broadcast_test.go +++ b/pkg/tcpip/tests/integration/multicast_broadcast_test.go @@ -15,6 +15,7 @@ package integration_test import ( + "net" "testing" "github.com/google/go-cmp/cmp" @@ -25,11 +26,195 @@ import ( "gvisor.dev/gvisor/pkg/tcpip/network/ipv4" "gvisor.dev/gvisor/pkg/tcpip/network/ipv6" "gvisor.dev/gvisor/pkg/tcpip/stack" + "gvisor.dev/gvisor/pkg/tcpip/transport/icmp" "gvisor.dev/gvisor/pkg/tcpip/transport/udp" "gvisor.dev/gvisor/pkg/waiter" ) -const defaultMTU = 1280 +const ( + defaultMTU = 1280 + ttl = 255 +) + +var ( + ipv4Addr = tcpip.AddressWithPrefix{ + Address: tcpip.Address(net.ParseIP("192.168.1.58").To4()), + PrefixLen: 24, + } + ipv4Subnet = ipv4Addr.Subnet() + ipv4SubnetBcast = ipv4Subnet.Broadcast() + + ipv6Addr = tcpip.AddressWithPrefix{ + Address: tcpip.Address(net.ParseIP("200a::1").To16()), + PrefixLen: 64, + } + ipv6Subnet = ipv6Addr.Subnet() + ipv6SubnetBcast = ipv6Subnet.Broadcast() + + // Remote addrs. + remoteIPv4Addr = tcpip.Address(net.ParseIP("10.0.0.1").To4()) + remoteIPv6Addr = tcpip.Address(net.ParseIP("200b::1").To16()) +) + +// TestPingMulticastBroadcast tests that responding to an Echo Request destined +// to a multicast or broadcast address uses a unicast source address for the +// reply. +func TestPingMulticastBroadcast(t *testing.T) { + const nicID = 1 + + rxIPv4ICMP := func(e *channel.Endpoint, dst tcpip.Address) { + totalLen := header.IPv4MinimumSize + header.ICMPv4MinimumSize + hdr := buffer.NewPrependable(totalLen) + pkt := header.ICMPv4(hdr.Prepend(header.ICMPv4MinimumSize)) + pkt.SetType(header.ICMPv4Echo) + pkt.SetCode(0) + pkt.SetChecksum(0) + pkt.SetChecksum(^header.Checksum(pkt, 0)) + ip := header.IPv4(hdr.Prepend(header.IPv4MinimumSize)) + ip.Encode(&header.IPv4Fields{ + IHL: header.IPv4MinimumSize, + TotalLength: uint16(totalLen), + Protocol: uint8(icmp.ProtocolNumber4), + TTL: ttl, + SrcAddr: remoteIPv4Addr, + DstAddr: dst, + }) + + e.InjectInbound(header.IPv4ProtocolNumber, &stack.PacketBuffer{ + Data: hdr.View().ToVectorisedView(), + }) + } + + rxIPv6ICMP := func(e *channel.Endpoint, dst tcpip.Address) { + totalLen := header.IPv6MinimumSize + header.ICMPv6MinimumSize + hdr := buffer.NewPrependable(totalLen) + pkt := header.ICMPv6(hdr.Prepend(header.ICMPv6MinimumSize)) + pkt.SetType(header.ICMPv6EchoRequest) + pkt.SetCode(0) + pkt.SetChecksum(0) + pkt.SetChecksum(header.ICMPv6Checksum(pkt, remoteIPv6Addr, dst, buffer.VectorisedView{})) + ip := header.IPv6(hdr.Prepend(header.IPv6MinimumSize)) + ip.Encode(&header.IPv6Fields{ + PayloadLength: header.ICMPv6MinimumSize, + NextHeader: uint8(icmp.ProtocolNumber6), + HopLimit: ttl, + SrcAddr: remoteIPv6Addr, + DstAddr: dst, + }) + + e.InjectInbound(header.IPv6ProtocolNumber, &stack.PacketBuffer{ + Data: hdr.View().ToVectorisedView(), + }) + } + + tests := []struct { + name string + dstAddr tcpip.Address + }{ + { + name: "IPv4 unicast", + dstAddr: ipv4Addr.Address, + }, + { + name: "IPv4 directed broadcast", + dstAddr: ipv4SubnetBcast, + }, + { + name: "IPv4 broadcast", + dstAddr: header.IPv4Broadcast, + }, + { + name: "IPv4 all-systems multicast", + dstAddr: header.IPv4AllSystems, + }, + { + name: "IPv6 unicast", + dstAddr: ipv6Addr.Address, + }, + { + name: "IPv6 all-nodes multicast", + dstAddr: header.IPv6AllNodesMulticastAddress, + }, + } + + for _, test := range tests { + t.Run(test.name, func(t *testing.T) { + ipv4Proto := ipv4.NewProtocol() + ipv6Proto := ipv6.NewProtocol() + s := stack.New(stack.Options{ + NetworkProtocols: []stack.NetworkProtocol{ipv4Proto, ipv6Proto}, + TransportProtocols: []stack.TransportProtocol{icmp.NewProtocol4(), icmp.NewProtocol6()}, + }) + // We only expect a single packet in response to our ICMP Echo Request. + e := channel.New(1, defaultMTU, "") + if err := s.CreateNIC(nicID, e); err != nil { + t.Fatalf("CreateNIC(%d, _): %s", nicID, err) + } + ipv4ProtoAddr := tcpip.ProtocolAddress{Protocol: header.IPv4ProtocolNumber, AddressWithPrefix: ipv4Addr} + if err := s.AddProtocolAddress(nicID, ipv4ProtoAddr); err != nil { + t.Fatalf("AddProtocolAddress(%d, %+v): %s", nicID, ipv4ProtoAddr, err) + } + ipv6ProtoAddr := tcpip.ProtocolAddress{Protocol: header.IPv6ProtocolNumber, AddressWithPrefix: ipv6Addr} + if err := s.AddProtocolAddress(nicID, ipv6ProtoAddr); err != nil { + t.Fatalf("AddProtocolAddress(%d, %+v): %s", nicID, ipv6ProtoAddr, err) + } + + // Default routes for IPv4 and IPv6 so ICMP can find a route to the remote + // node when attempting to send the ICMP Echo Reply. + s.SetRouteTable([]tcpip.Route{ + tcpip.Route{ + Destination: header.IPv6EmptySubnet, + NIC: nicID, + }, + tcpip.Route{ + Destination: header.IPv4EmptySubnet, + NIC: nicID, + }, + }) + + var rxICMP func(*channel.Endpoint, tcpip.Address) + var expectedSrc tcpip.Address + var expectedDst tcpip.Address + var proto stack.NetworkProtocol + switch l := len(test.dstAddr); l { + case header.IPv4AddressSize: + rxICMP = rxIPv4ICMP + expectedSrc = ipv4Addr.Address + expectedDst = remoteIPv4Addr + proto = ipv4Proto + case header.IPv6AddressSize: + rxICMP = rxIPv6ICMP + expectedSrc = ipv6Addr.Address + expectedDst = remoteIPv6Addr + proto = ipv6Proto + default: + t.Fatalf("got unexpected address length = %d bytes", l) + } + + rxICMP(e, test.dstAddr) + pkt, ok := e.Read() + if !ok { + t.Fatal("expected ICMP response") + } + + if pkt.Route.LocalAddress != expectedSrc { + t.Errorf("got pkt.Route.LocalAddress = %s, want = %s", pkt.Route.LocalAddress, expectedSrc) + } + if pkt.Route.RemoteAddress != expectedDst { + t.Errorf("got pkt.Route.RemoteAddress = %s, want = %s", pkt.Route.RemoteAddress, expectedDst) + } + + src, dst := proto.ParseAddresses(pkt.Pkt.NetworkHeader) + if src != expectedSrc { + t.Errorf("got pkt source = %s, want = %s", src, expectedSrc) + } + if dst != expectedDst { + t.Errorf("got pkt destination = %s, want = %s", dst, expectedDst) + } + }) + } + +} // TestIncomingMulticastAndBroadcast tests receiving a packet destined to some // multicast or broadcast address. @@ -38,31 +223,10 @@ func TestIncomingMulticastAndBroadcast(t *testing.T) { nicID = 1 remotePort = 5555 localPort = 80 - ttl = 255 ) data := []byte{1, 2, 3, 4} - // Local IPv4 subnet: 192.168.1.58/24 - ipv4Addr := tcpip.AddressWithPrefix{ - Address: "\xc0\xa8\x01\x3a", - PrefixLen: 24, - } - ipv4Subnet := ipv4Addr.Subnet() - ipv4SubnetBcast := ipv4Subnet.Broadcast() - - // Local IPv6 subnet: 200a::1/64 - ipv6Addr := tcpip.AddressWithPrefix{ - Address: "\x20\x0a\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01", - PrefixLen: 64, - } - ipv6Subnet := ipv6Addr.Subnet() - ipv6SubnetBcast := ipv6Subnet.Broadcast() - - // Remote addrs. - remoteIPv4Addr := tcpip.Address("\x64\x0a\x7b\x18") - remoteIPv6Addr := tcpip.Address("\x20\x0b\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02") - rxIPv4UDP := func(e *channel.Endpoint, dst tcpip.Address) { payloadLen := header.UDPMinimumSize + len(data) totalLen := header.IPv4MinimumSize + payloadLen diff --git a/pkg/tcpip/transport/udp/endpoint.go b/pkg/tcpip/transport/udp/endpoint.go index b7d735889..444b5b01c 100644 --- a/pkg/tcpip/transport/udp/endpoint.go +++ b/pkg/tcpip/transport/udp/endpoint.go @@ -499,7 +499,7 @@ func (e *endpoint) write(p tcpip.Payloader, opts tcpip.WriteOptions) (int64, <-c resolve = route.Resolve } - if !e.broadcast && route.IsBroadcast() { + if !e.broadcast && route.IsOutboundBroadcast() { return 0, nil, tcpip.ErrBroadcastDisabled } |