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-rw-r--r--pkg/tcpip/stack/BUILD1
-rw-r--r--pkg/tcpip/stack/route.go10
-rw-r--r--pkg/tcpip/stack/stack.go15
-rw-r--r--pkg/tcpip/stack/stack_test.go223
4 files changed, 245 insertions, 4 deletions
diff --git a/pkg/tcpip/stack/BUILD b/pkg/tcpip/stack/BUILD
index 6b9a6b316..2b4455318 100644
--- a/pkg/tcpip/stack/BUILD
+++ b/pkg/tcpip/stack/BUILD
@@ -110,6 +110,7 @@ go_test(
"//pkg/tcpip/transport/udp",
"//pkg/waiter",
"@com_github_google_go_cmp//cmp:go_default_library",
+ "@com_github_google_go_cmp//cmp/cmpopts:go_default_library",
],
)
diff --git a/pkg/tcpip/stack/route.go b/pkg/tcpip/stack/route.go
index d65f8049e..91e0110f1 100644
--- a/pkg/tcpip/stack/route.go
+++ b/pkg/tcpip/stack/route.go
@@ -48,6 +48,10 @@ type Route struct {
// Loop controls where WritePacket should send packets.
Loop PacketLooping
+
+ // directedBroadcast indicates whether this route is sending a directed
+ // broadcast packet.
+ directedBroadcast bool
}
// makeRoute initializes a new route. It takes ownership of the provided
@@ -275,6 +279,12 @@ 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 {
+ // Only IPv4 has a notion of broadcast.
+ return r.directedBroadcast || r.RemoteAddress == header.IPv4Broadcast
+}
+
// 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.go b/pkg/tcpip/stack/stack.go
index a6faa22c2..36626e051 100644
--- a/pkg/tcpip/stack/stack.go
+++ b/pkg/tcpip/stack/stack.go
@@ -1284,9 +1284,9 @@ func (s *Stack) FindRoute(id tcpip.NICID, localAddr, remoteAddr tcpip.Address, n
s.mu.RLock()
defer s.mu.RUnlock()
- isBroadcast := remoteAddr == header.IPv4Broadcast
+ isLocalBroadcast := remoteAddr == header.IPv4Broadcast
isMulticast := header.IsV4MulticastAddress(remoteAddr) || header.IsV6MulticastAddress(remoteAddr)
- needRoute := !(isBroadcast || isMulticast || header.IsV6LinkLocalAddress(remoteAddr))
+ needRoute := !(isLocalBroadcast || isMulticast || header.IsV6LinkLocalAddress(remoteAddr))
if id != 0 && !needRoute {
if nic, ok := s.nics[id]; ok && nic.enabled() {
if ref := s.getRefEP(nic, localAddr, remoteAddr, netProto); ref != nil {
@@ -1307,9 +1307,16 @@ func (s *Stack) FindRoute(id tcpip.NICID, localAddr, remoteAddr tcpip.Address, n
}
r := makeRoute(netProto, ref.ep.ID().LocalAddress, remoteAddr, nic.linkEP.LinkAddress(), ref, s.handleLocal && !nic.isLoopback(), multicastLoop && !nic.isLoopback())
- if needRoute {
- r.NextHop = route.Gateway
+ r.directedBroadcast = route.Destination.IsBroadcast(remoteAddr)
+
+ if len(route.Gateway) > 0 {
+ if needRoute {
+ r.NextHop = route.Gateway
+ }
+ } else if r.directedBroadcast {
+ r.RemoteLinkAddress = header.EthernetBroadcastAddress
}
+
return r, nil
}
}
diff --git a/pkg/tcpip/stack/stack_test.go b/pkg/tcpip/stack/stack_test.go
index 101ca2206..f22062889 100644
--- a/pkg/tcpip/stack/stack_test.go
+++ b/pkg/tcpip/stack/stack_test.go
@@ -27,6 +27,7 @@ import (
"time"
"github.com/google/go-cmp/cmp"
+ "github.com/google/go-cmp/cmp/cmpopts"
"gvisor.dev/gvisor/pkg/rand"
"gvisor.dev/gvisor/pkg/tcpip"
"gvisor.dev/gvisor/pkg/tcpip/buffer"
@@ -3418,3 +3419,225 @@ func TestStackSendBufferSizeOption(t *testing.T) {
})
}
}
+
+func TestOutgoingSubnetBroadcast(t *testing.T) {
+ const (
+ unspecifiedNICID = 0
+ nicID1 = 1
+ )
+
+ defaultAddr := tcpip.AddressWithPrefix{
+ Address: header.IPv4Any,
+ PrefixLen: 0,
+ }
+ defaultSubnet := defaultAddr.Subnet()
+ ipv4Addr := tcpip.AddressWithPrefix{
+ Address: "\xc0\xa8\x01\x3a",
+ PrefixLen: 24,
+ }
+ ipv4Subnet := ipv4Addr.Subnet()
+ ipv4SubnetBcast := ipv4Subnet.Broadcast()
+ ipv4Gateway := tcpip.Address("\xc0\xa8\x01\x01")
+ ipv4AddrPrefix31 := tcpip.AddressWithPrefix{
+ Address: "\xc0\xa8\x01\x3a",
+ PrefixLen: 31,
+ }
+ ipv4Subnet31 := ipv4AddrPrefix31.Subnet()
+ ipv4Subnet31Bcast := ipv4Subnet31.Broadcast()
+ ipv4AddrPrefix32 := tcpip.AddressWithPrefix{
+ Address: "\xc0\xa8\x01\x3a",
+ PrefixLen: 32,
+ }
+ ipv4Subnet32 := ipv4AddrPrefix32.Subnet()
+ ipv4Subnet32Bcast := ipv4Subnet32.Broadcast()
+ 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()
+ remNetAddr := tcpip.AddressWithPrefix{
+ Address: "\x64\x0a\x7b\x18",
+ PrefixLen: 24,
+ }
+ remNetSubnet := remNetAddr.Subnet()
+ remNetSubnetBcast := remNetSubnet.Broadcast()
+
+ tests := []struct {
+ name string
+ nicAddr tcpip.ProtocolAddress
+ routes []tcpip.Route
+ remoteAddr tcpip.Address
+ expectedRoute stack.Route
+ }{
+ // Broadcast to a locally attached subnet populates the broadcast MAC.
+ {
+ name: "IPv4 Broadcast to local subnet",
+ nicAddr: tcpip.ProtocolAddress{
+ Protocol: header.IPv4ProtocolNumber,
+ AddressWithPrefix: ipv4Addr,
+ },
+ routes: []tcpip.Route{
+ {
+ Destination: ipv4Subnet,
+ NIC: nicID1,
+ },
+ },
+ remoteAddr: ipv4SubnetBcast,
+ expectedRoute: stack.Route{
+ LocalAddress: ipv4Addr.Address,
+ RemoteAddress: ipv4SubnetBcast,
+ RemoteLinkAddress: header.EthernetBroadcastAddress,
+ NetProto: header.IPv4ProtocolNumber,
+ Loop: stack.PacketOut,
+ },
+ },
+ // Broadcast to a locally attached /31 subnet does not populate the
+ // broadcast MAC.
+ {
+ name: "IPv4 Broadcast to local /31 subnet",
+ nicAddr: tcpip.ProtocolAddress{
+ Protocol: header.IPv4ProtocolNumber,
+ AddressWithPrefix: ipv4AddrPrefix31,
+ },
+ routes: []tcpip.Route{
+ {
+ Destination: ipv4Subnet31,
+ NIC: nicID1,
+ },
+ },
+ remoteAddr: ipv4Subnet31Bcast,
+ expectedRoute: stack.Route{
+ LocalAddress: ipv4AddrPrefix31.Address,
+ RemoteAddress: ipv4Subnet31Bcast,
+ NetProto: header.IPv4ProtocolNumber,
+ Loop: stack.PacketOut,
+ },
+ },
+ // Broadcast to a locally attached /32 subnet does not populate the
+ // broadcast MAC.
+ {
+ name: "IPv4 Broadcast to local /32 subnet",
+ nicAddr: tcpip.ProtocolAddress{
+ Protocol: header.IPv4ProtocolNumber,
+ AddressWithPrefix: ipv4AddrPrefix32,
+ },
+ routes: []tcpip.Route{
+ {
+ Destination: ipv4Subnet32,
+ NIC: nicID1,
+ },
+ },
+ remoteAddr: ipv4Subnet32Bcast,
+ expectedRoute: stack.Route{
+ LocalAddress: ipv4AddrPrefix32.Address,
+ RemoteAddress: ipv4Subnet32Bcast,
+ NetProto: header.IPv4ProtocolNumber,
+ Loop: stack.PacketOut,
+ },
+ },
+ // IPv6 has no notion of a broadcast.
+ {
+ name: "IPv6 'Broadcast' to local subnet",
+ nicAddr: tcpip.ProtocolAddress{
+ Protocol: header.IPv6ProtocolNumber,
+ AddressWithPrefix: ipv6Addr,
+ },
+ routes: []tcpip.Route{
+ {
+ Destination: ipv6Subnet,
+ NIC: nicID1,
+ },
+ },
+ remoteAddr: ipv6SubnetBcast,
+ expectedRoute: stack.Route{
+ LocalAddress: ipv6Addr.Address,
+ RemoteAddress: ipv6SubnetBcast,
+ NetProto: header.IPv6ProtocolNumber,
+ Loop: stack.PacketOut,
+ },
+ },
+ // Broadcast to a remote subnet in the route table is send to the next-hop
+ // gateway.
+ {
+ name: "IPv4 Broadcast to remote subnet",
+ nicAddr: tcpip.ProtocolAddress{
+ Protocol: header.IPv4ProtocolNumber,
+ AddressWithPrefix: ipv4Addr,
+ },
+ routes: []tcpip.Route{
+ {
+ Destination: remNetSubnet,
+ Gateway: ipv4Gateway,
+ NIC: nicID1,
+ },
+ },
+ remoteAddr: remNetSubnetBcast,
+ expectedRoute: stack.Route{
+ LocalAddress: ipv4Addr.Address,
+ RemoteAddress: remNetSubnetBcast,
+ NextHop: ipv4Gateway,
+ NetProto: header.IPv4ProtocolNumber,
+ Loop: stack.PacketOut,
+ },
+ },
+ // Broadcast to an unknown subnet follows the default route. Note that this
+ // is essentially just routing an unknown destination IP, because w/o any
+ // subnet prefix information a subnet broadcast address is just a normal IP.
+ {
+ name: "IPv4 Broadcast to unknown subnet",
+ nicAddr: tcpip.ProtocolAddress{
+ Protocol: header.IPv4ProtocolNumber,
+ AddressWithPrefix: ipv4Addr,
+ },
+ routes: []tcpip.Route{
+ {
+ Destination: defaultSubnet,
+ Gateway: ipv4Gateway,
+ NIC: nicID1,
+ },
+ },
+ remoteAddr: remNetSubnetBcast,
+ expectedRoute: stack.Route{
+ LocalAddress: ipv4Addr.Address,
+ RemoteAddress: remNetSubnetBcast,
+ NextHop: ipv4Gateway,
+ NetProto: header.IPv4ProtocolNumber,
+ Loop: stack.PacketOut,
+ },
+ },
+ }
+
+ for _, test := range tests {
+ t.Run(test.name, func(t *testing.T) {
+ s := stack.New(stack.Options{
+ NetworkProtocols: []stack.NetworkProtocol{ipv4.NewProtocol(), ipv6.NewProtocol()},
+ })
+ ep := channel.New(0, defaultMTU, "")
+ if err := s.CreateNIC(nicID1, ep); err != nil {
+ t.Fatalf("CreateNIC(%d, _): %s", nicID1, err)
+ }
+ if err := s.AddProtocolAddress(nicID1, test.nicAddr); err != nil {
+ t.Fatalf("AddProtocolAddress(%d, %+v): %s", nicID1, test.nicAddr, err)
+ }
+
+ s.SetRouteTable(test.routes)
+
+ var netProto tcpip.NetworkProtocolNumber
+ switch l := len(test.remoteAddr); l {
+ case header.IPv4AddressSize:
+ netProto = header.IPv4ProtocolNumber
+ case header.IPv6AddressSize:
+ netProto = header.IPv6ProtocolNumber
+ default:
+ t.Fatalf("got unexpected address length = %d bytes", l)
+ }
+
+ if r, err := s.FindRoute(unspecifiedNICID, "" /* localAddr */, test.remoteAddr, netProto, false /* multicastLoop */); err != nil {
+ t.Fatalf("FindRoute(%d, '', %s, %d): %s", unspecifiedNICID, test.remoteAddr, netProto, err)
+ } else if diff := cmp.Diff(r, test.expectedRoute, cmpopts.IgnoreUnexported(r)); diff != "" {
+ t.Errorf("route mismatch (-want +got):\n%s", diff)
+ }
+ })
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-02 11:01:21 +0000