diff options
| author | Ghanan Gowripalan <ghanan@google.com> | 2020-09-15 11:51:17 -0700 |
|---|---|---|
| committer | gVisor bot <gvisor-bot@google.com> | 2020-09-15 11:53:00 -0700 |
| commit | d3880b76cbeaa1cadc38388d5684e00172566376 (patch) | |
| tree | ae707e967a334a1f4c4652df4ee138362f762e5f /pkg/tcpip/stack/stack.go | |
| parent | 52ffeb2d6475fa2e427daf246abdd32e4825f3f8 (diff) | |
Don't conclude broadcast from route destination
The routing table (in its current) form should not be used to make
decisions about whether a remote address is a broadcast address or
not (for IPv4).
Note, a destination subnet does not always map to a network.
E.g. RouterA may have a route to 192.168.0.0/22 through RouterB,
but RouterB may be configured with 4x /24 subnets on 4 different
interfaces.
See https://github.com/google/gvisor/issues/3938.
PiperOrigin-RevId: 331819868
Diffstat (limited to 'pkg/tcpip/stack/stack.go')
| -rw-r--r-- | pkg/tcpip/stack/stack.go | 4 |
1 files changed, 1 insertions, 3 deletions
diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go index def8b0b43..6a683545d 100644 --- a/pkg/tcpip/stack/stack.go +++ b/pkg/tcpip/stack/stack.go @@ -1311,13 +1311,11 @@ func (s *Stack) FindRoute(id tcpip.NICID, localAddr, remoteAddr tcpip.Address, n } r := makeRoute(netProto, ref.address(), remoteAddr, nic.linkEP.LinkAddress(), ref, s.handleLocal && !nic.isLoopback(), multicastLoop && !nic.isLoopback()) - r.directedBroadcast = route.Destination.IsBroadcast(remoteAddr) - if len(route.Gateway) > 0 { if needRoute { r.NextHop = route.Gateway } - } else if r.directedBroadcast { + } else if subnet := ref.addrWithPrefix().Subnet(); subnet.IsBroadcast(remoteAddr) { r.RemoteLinkAddress = header.EthernetBroadcastAddress } |