feat: reset packet fifo on bad packet

* This should avoid sending bad ethernet frames

hdl/ccn_pack.vhd

@@ -112,6 +112,7 @@ architecture rtl of ccn_pack is
     signal fifo_tlast               : std_logic;
     signal fifo_tuser               : std_logic_vector(0 downto 0);
     signal fifo_tuser_slv           : std_logic_vector(7 downto 0);
+    signal fifo_err_rst             : std_logic;
 
     -- Some constant for mapping
     constant C_TKEEP_S00            : std_logic_vector(23 downto 0)              := (others => '1');
@@ -291,10 +292,11 @@ begin
     -- FIFO --
     ----------
     fifo_tuser(0) <= or_reduce(fifo_tuser_slv);
+    fifo_err_rst  <= (not fifo_tuser(0)) and aresetn;
 
     inst_fifo: entity work.ccn_axis_fifo_pframe
     port map(
-        s_axis_aresetn => aresetn,
+        s_axis_aresetn => fifo_err_rst,
         s_axis_aclk    => aclk,
         m_axis_aclk    => m_axis_clk,
         s_axis_tvalid  => fifo_tvalid,