Track and export socket state.

This is necessary for implementing network diagnostic interfaces like
/proc/net/{tcp,udp,unix} and sock_diag(7).

For pass-through endpoints such as hostinet, we obtain the socket
state from the backend. For netstack, we add explicit tracking of TCP
states.

PiperOrigin-RevId: 251934850

1 files changed, 5 insertions, 0 deletions

diff --git a/pkg/sentry/socket/netlink/socket.go b/pkg/sentry/socket/netlink/socket.go
index afd06ca33..16c79aa33 100644
--- a/pkg/sentry/socket/netlink/socket.go
+++ b/pkg/sentry/socket/netlink/socket.go
@@ -616,3 +616,8 @@ func (s *Socket) Write(ctx context.Context, _ *fs.File, src usermem.IOSequence,
 	n, err := s.sendMsg(ctx, src, nil, 0, socket.ControlMessages{})
 	return int64(n), err.ToError()
 }
+
+// State implements socket.Socket.State.
+func (s *Socket) State() uint32 {
+	return s.ep.State()
+}