Ltac prove_in :=
    match goal with
      | [ _ : nwPackets ?net = _,
              _ : In (?p : packet) _ |- _] =>
        assert (In p (nwPackets net)) by (repeat find_rewrite; do_in_app; intuition)
      | [ _ : nwPackets ?net = _,
              _ : pBody ?p = _ |- _] =>
        assert (In p (nwPackets net)) by (repeat find_rewrite; intuition)
    end.

Lemma contiguous_log_property : log_property (fun l => contiguous_range_exact_lo l 0).