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/rtl/vhdl/IPv4_RX.vhd
1,533 → 1,539
----------------------------------------------------------------------------------
-- Company:
-- Engineer: Peter Fall
--
-- Create Date: 16:20:42 06/01/2011
-- Design Name:
-- Module Name: IPv4_RX - Behavioral
-- Project Name:
-- Target Devices:
-- Tool versions:
-- Description:
-- handle simple IP RX
-- doesnt handle reassembly
-- checks and filters for IP protocol
-- checks and filters for IP addr
-- Handle IPv4 protocol
-- Dependencies:
--
-- Revision:
-- Revision 0.01 - File Created
-- Revision 0.02 - Improved error handling
-- Revision 0.03 - Added handling of broadcast address
-- Additional Comments:
--
----------------------------------------------------------------------------------
library IEEE;
use IEEE.STD_LOGIC_1164.all;
use IEEE.NUMERIC_STD.all;
use work.axi.all;
use work.ipv4_types.all;
use work.arp_types.all;
 
entity IPv4_RX is
port (
-- IP Layer signals
ip_rx : out ipv4_rx_type;
ip_rx_start : out std_logic; -- indicates receipt of ip frame.
-- system signals
clk : in std_logic; -- same clock used to clock mac data and ip data
reset : in std_logic;
our_ip_address : in std_logic_vector (31 downto 0);
rx_pkt_count : out std_logic_vector(7 downto 0); -- number of IP pkts received for us
-- MAC layer RX signals
mac_data_in : in std_logic_vector (7 downto 0); -- ethernet frame (from dst mac addr through to last byte of frame)
mac_data_in_valid : in std_logic; -- indicates data_in valid on clock
mac_data_in_last : in std_logic -- indicates last data in frame
);
end IPv4_RX;
 
architecture Behavioral of IPv4_RX is
 
type rx_state_type is (IDLE, ETH_HDR, IP_HDR, USER_DATA, WAIT_END, ERR);
 
type rx_event_type is (NO_EVENT, DATA);
type count_mode_type is (RST, INCR, HOLD);
type settable_count_mode_type is (RST, INCR, SET_VAL, HOLD);
type set_clr_type is (SET, CLR, HOLD);
 
 
-- state variables
signal rx_state : rx_state_type;
signal rx_count : unsigned (15 downto 0);
signal src_ip : std_logic_vector (31 downto 0); -- src IP captured from input
signal dst_ip : std_logic_vector (23 downto 0); -- 1st 3 bytes of dst IP captured from input
signal is_broadcast_reg : std_logic;
signal protocol : std_logic_vector (7 downto 0); -- src protocol captured from input
signal data_len : std_logic_vector (15 downto 0); -- src data length captured from input
signal ip_rx_start_reg : std_logic; -- indicates start of user data
signal hdr_valid_reg : std_logic; -- indicates that hdr data is valid
signal frame_err_cnt : unsigned (7 downto 0); -- number of frame errors
signal error_code_reg : std_logic_vector (3 downto 0);
signal rx_pkt_counter : unsigned (7 downto 0); -- number of rx frames received for us
 
-- rx control signals
signal next_rx_state : rx_state_type;
signal set_rx_state : std_logic;
signal rx_event : rx_event_type;
signal rx_count_mode : settable_count_mode_type;
signal set_dst_ip3 : std_logic;
signal set_dst_ip2 : std_logic;
signal set_dst_ip1 : std_logic;
signal set_ip3 : std_logic;
signal set_ip2 : std_logic;
signal set_ip1 : std_logic;
signal set_ip0 : std_logic;
signal set_protocol : std_logic;
signal set_len_H : std_logic;
signal set_len_L : std_logic;
signal set_ip_rx_start : set_clr_type;
signal set_hdr_valid : set_clr_type;
signal set_frame_err_cnt : count_mode_type;
signal dataval : std_logic_vector (7 downto 0);
signal rx_count_val : unsigned (15 downto 0);
signal set_error_code : std_logic;
signal error_code_val : std_logic_vector (3 downto 0);
signal set_pkt_cnt : count_mode_type;
signal set_data_last : std_logic;
signal dst_ip_rx : std_logic_vector (31 downto 0);
signal set_is_broadcast : set_clr_type;
 
 
-- IP datagram header format
--
-- 0 4 8 16 19 24 31
-- --------------------------------------------------------------------------------------------
-- | Version | *Header | Service Type | Total Length including header |
-- | (4) | Length | (ignored) | (in bytes) |
-- --------------------------------------------------------------------------------------------
-- | Identification | Flags | Fragment Offset |
-- | | | (in 32 bit words) |
-- --------------------------------------------------------------------------------------------
-- | Time To Live | Protocol | Header Checksum |
-- | (ignored) | | |
-- --------------------------------------------------------------------------------------------
-- | Source IP Address |
-- | |
-- --------------------------------------------------------------------------------------------
-- | Destination IP Address |
-- | |
-- --------------------------------------------------------------------------------------------
-- | Options (if any - ignored) | Padding |
-- | | (if needed) |
-- --------------------------------------------------------------------------------------------
-- | Data |
-- | |
-- --------------------------------------------------------------------------------------------
-- | .... |
-- | |
-- --------------------------------------------------------------------------------------------
--
-- * - in 32 bit words
begin
 
-----------------------------------------------------------------------
-- combinatorial process to implement FSM and determine control signals
-----------------------------------------------------------------------
 
rx_combinatorial : process (
-- input signals
mac_data_in, mac_data_in_valid, mac_data_in_last, our_ip_address,
-- state variables
rx_state, rx_count, src_ip, dst_ip, protocol, data_len, ip_rx_start_reg, hdr_valid_reg,
frame_err_cnt, error_code_reg, rx_pkt_counter, is_broadcast_reg,
-- control signals
next_rx_state, set_rx_state, rx_event, rx_count_mode,
set_ip3, set_ip2, set_ip1, set_ip0, set_protocol, set_len_H, set_len_L,
set_dst_ip3, set_dst_ip2, set_dst_ip1,
set_ip_rx_start, set_hdr_valid, set_frame_err_cnt, dataval, rx_count_val,
set_error_code, error_code_val, set_pkt_cnt, set_data_last, dst_ip_rx, set_is_broadcast
)
begin
-- set output followers
ip_rx_start <= ip_rx_start_reg;
ip_rx.hdr.is_valid <= hdr_valid_reg;
ip_rx.hdr.protocol <= protocol;
ip_rx.hdr.data_length <= data_len;
ip_rx.hdr.src_ip_addr <= src_ip;
ip_rx.hdr.num_frame_errors <= std_logic_vector(frame_err_cnt);
ip_rx.hdr.last_error_code <= error_code_reg;
ip_rx.hdr.is_broadcast <= is_broadcast_reg;
rx_pkt_count <= std_logic_vector(rx_pkt_counter);
 
-- transfer data upstream if in user data phase
if rx_state = USER_DATA then
ip_rx.data.data_in <= mac_data_in;
ip_rx.data.data_in_valid <= mac_data_in_valid;
ip_rx.data.data_in_last <= set_data_last;
else
ip_rx.data.data_in <= (others => '0');
ip_rx.data.data_in_valid <= '0';
ip_rx.data.data_in_last <= '0';
end if;
 
-- set signal defaults
next_rx_state <= IDLE;
set_rx_state <= '0';
rx_event <= NO_EVENT;
rx_count_mode <= HOLD;
set_ip3 <= '0';
set_ip2 <= '0';
set_ip1 <= '0';
set_ip0 <= '0';
set_dst_ip3 <= '0';
set_dst_ip2 <= '0';
set_dst_ip1 <= '0';
set_protocol <= '0';
set_len_H <= '0';
set_len_L <= '0';
set_ip_rx_start <= HOLD;
set_hdr_valid <= HOLD;
set_frame_err_cnt <= HOLD;
rx_count_val <= x"0000";
set_error_code <= '0';
error_code_val <= RX_EC_NONE;
set_pkt_cnt <= HOLD;
dataval <= (others => '0');
set_data_last <= '0';
dst_ip_rx <= (others => '0');
set_is_broadcast <= HOLD;
 
-- determine event (if any)
if mac_data_in_valid = '1' then
rx_event <= DATA;
dataval <= mac_data_in;
end if;
 
-- RX FSM
case rx_state is
when IDLE =>
rx_count_mode <= RST;
case rx_event is
when NO_EVENT => -- (nothing to do)
when DATA =>
rx_count_mode <= INCR;
set_hdr_valid <= CLR;
next_rx_state <= ETH_HDR;
set_rx_state <= '1';
end case;
 
when ETH_HDR =>
case rx_event is
when NO_EVENT => -- (nothing to do)
when DATA =>
if rx_count = x"000d" then
rx_count_mode <= RST;
next_rx_state <= IP_HDR;
set_rx_state <= '1';
else
rx_count_mode <= INCR;
end if;
-- handle early frame termination
if mac_data_in_last = '1' then
error_code_val <= RX_EC_ET_ETH;
set_error_code <= '1';
set_frame_err_cnt <= INCR;
set_ip_rx_start <= CLR;
set_data_last <= '1';
next_rx_state <= IDLE;
set_rx_state <= '1';
else
case rx_count is
when x"000c" =>
if mac_data_in /= x"08" then -- ignore pkts that are not type=IP
next_rx_state <= WAIT_END;
set_rx_state <= '1';
end if;
when x"000d" =>
if mac_data_in /= x"00" then -- ignore pkts that are not type=IP
next_rx_state <= WAIT_END;
set_rx_state <= '1';
end if;
when others => -- ignore other bytes in eth header
end case;
end if;
end case;
 
when IP_HDR =>
case rx_event is
when NO_EVENT => -- (nothing to do)
when DATA =>
if rx_count = x"0013" then
rx_count_val <= x"0001"; -- start counter at 1
rx_count_mode <= SET_VAL;
else
rx_count_mode <= INCR;
end if;
-- handle early frame termination
if mac_data_in_last = '1' then
error_code_val <= RX_EC_ET_IP;
set_error_code <= '1';
set_frame_err_cnt <= INCR;
set_ip_rx_start <= CLR;
set_data_last <= '1';
next_rx_state <= IDLE;
set_rx_state <= '1';
else
case rx_count is
when x"0000" =>
if mac_data_in /= x"45" then -- ignore pkts that are not v4 with 5 header words
next_rx_state <= WAIT_END;
set_rx_state <= '1';
end if;
when x"0002" => set_len_H <= '1';
when x"0003" => set_len_L <= '1';
 
when x"0006" =>
if (mac_data_in(7) = '1') or (mac_data_in (4 downto 0) /= "00000") then
-- ignore pkts that require reassembly (MF=1 or frag offst /= 0)
next_rx_state <= WAIT_END;
set_rx_state <= '1';
end if;
when x"0007" =>
if mac_data_in /= x"00" then -- ignore pkts that require reassembly (frag offst /= 0)
next_rx_state <= WAIT_END;
set_rx_state <= '1';
end if;
 
when x"0009" => set_protocol <= '1';
 
when x"000c" => set_ip3 <= '1';
when x"000d" => set_ip2 <= '1';
when x"000e" => set_ip1 <= '1';
when x"000f" => set_ip0 <= '1';
 
when x"0010" => set_dst_ip3 <= '1';
if ((mac_data_in /= our_ip_address(31 downto 24)) and
(mac_data_in /= IP_BC_ADDR(31 downto 24)))then -- ignore pkts that are not addressed to us
next_rx_state <= WAIT_END;
set_rx_state <= '1';
end if;
when x"0011" => set_dst_ip2 <= '1';
if ((mac_data_in /= our_ip_address(23 downto 16)) and
(mac_data_in /= IP_BC_ADDR(23 downto 16)))then -- ignore pkts that are not addressed to us
next_rx_state <= WAIT_END;
set_rx_state <= '1';
end if;
when x"0012" => set_dst_ip1 <= '1';
if ((mac_data_in /= our_ip_address(15 downto 8)) and
(mac_data_in /= IP_BC_ADDR(15 downto 8)))then -- ignore pkts that are not addressed to us
next_rx_state <= WAIT_END;
set_rx_state <= '1';
end if;
 
when x"0013" =>
if ((mac_data_in /= our_ip_address(7 downto 0)) and
(mac_data_in /= IP_BC_ADDR(7 downto 0)))then -- ignore pkts that are not addressed to us
next_rx_state <= WAIT_END;
set_rx_state <= '1';
else
next_rx_state <= USER_DATA;
set_pkt_cnt <= INCR; -- count another pkt
set_rx_state <= '1';
set_ip_rx_start <= SET;
end if;
 
-- now have the dst IP addr
dst_ip_rx <= dst_ip & mac_data_in;
if dst_ip_rx = IP_BC_ADDR then
set_is_broadcast <= SET;
else
set_is_broadcast <= CLR;
end if;
set_hdr_valid <= SET; -- header values are now valid, although the pkt may not be for us
 
--if dst_ip_rx = our_ip_address or dst_ip_rx = IP_BC_ADDR then
-- next_rx_state <= USER_DATA;
-- set_pkt_cnt <= INCR; -- count another pkt received
-- set_rx_state <= '1';
-- set_ip_rx_start <= SET;
--else
-- next_rx_state <= WAIT_END;
-- set_rx_state <= '1';
--end if;
when others => -- ignore other bytes in ip header
end case;
end if;
end case;
when USER_DATA =>
case rx_event is
when NO_EVENT => -- (nothing to do)
when DATA =>
-- note: data gets transfered upstream as part of "output followers" processing
if rx_count = unsigned(data_len) then
set_ip_rx_start <= CLR;
rx_count_mode <= RST;
set_data_last <= '1';
if mac_data_in_last = '1' then
next_rx_state <= IDLE;
set_ip_rx_start <= CLR;
else
next_rx_state <= WAIT_END;
end if;
set_rx_state <= '1';
else
rx_count_mode <= INCR;
-- check for early frame termination
if mac_data_in_last = '1' then
error_code_val <= RX_EC_ET_USER;
set_error_code <= '1';
set_frame_err_cnt <= INCR;
set_ip_rx_start <= CLR;
next_rx_state <= IDLE;
set_rx_state <= '1';
end if;
end if;
end case;
 
when ERR =>
set_frame_err_cnt <= INCR;
set_ip_rx_start <= CLR;
if mac_data_in_last = '0' then
set_data_last <= '1';
next_rx_state <= WAIT_END;
set_rx_state <= '1';
else
next_rx_state <= IDLE;
set_rx_state <= '1';
end if;
 
when WAIT_END =>
case rx_event is
when NO_EVENT => -- (nothing to do)
when DATA =>
if mac_data_in_last = '1' then
set_data_last <= '1';
next_rx_state <= IDLE;
set_rx_state <= '1';
set_ip_rx_start <= CLR;
end if;
end case;
end case;
end process;
 
 
-----------------------------------------------------------------------------
-- sequential process to action control signals and change states and outputs
-----------------------------------------------------------------------------
 
rx_sequential : process (clk)--, reset)
begin
if rising_edge(clk) then
if reset = '1' then
-- reset state variables
rx_state <= IDLE;
rx_count <= x"0000";
src_ip <= (others => '0');
dst_ip <= (others => '0');
protocol <= (others => '0');
data_len <= (others => '0');
ip_rx_start_reg <= '0';
hdr_valid_reg <= '0';
is_broadcast_reg <= '0';
frame_err_cnt <= (others => '0');
error_code_reg <= RX_EC_NONE;
rx_pkt_counter <= x"00";
 
else
-- Next rx_state processing
if set_rx_state = '1' then
rx_state <= next_rx_state;
else
rx_state <= rx_state;
end if;
 
-- rx_count processing
case rx_count_mode is
when RST => rx_count <= x"0000";
when INCR => rx_count <= rx_count + 1;
when SET_VAL => rx_count <= rx_count_val;
when HOLD => rx_count <= rx_count;
end case;
 
-- frame error count processing
case set_frame_err_cnt is
when RST => frame_err_cnt <= x"00";
when INCR => frame_err_cnt <= frame_err_cnt + 1;
when HOLD => frame_err_cnt <= frame_err_cnt;
end case;
 
-- ip pkt processing
case set_pkt_cnt is
when RST => rx_pkt_counter <= x"00";
when INCR => rx_pkt_counter <= rx_pkt_counter + 1;
when HOLD => rx_pkt_counter <= rx_pkt_counter;
end case;
 
-- source ip capture
if (set_ip3 = '1') then src_ip(31 downto 24) <= dataval; end if;
if (set_ip2 = '1') then src_ip(23 downto 16) <= dataval; end if;
if (set_ip1 = '1') then src_ip(15 downto 8) <= dataval; end if;
if (set_ip0 = '1') then src_ip(7 downto 0) <= dataval; end if;
 
-- dst ip capture
if (set_dst_ip3 = '1') then dst_ip(23 downto 16) <= dataval; end if;
if (set_dst_ip2 = '1') then dst_ip(15 downto 8) <= dataval; end if;
if (set_dst_ip1 = '1') then dst_ip(7 downto 0) <= dataval; end if;
 
if (set_protocol = '1') then
protocol <= dataval;
else
protocol <= protocol;
end if;
 
if (set_len_H = '1') then
data_len (15 downto 8) <= dataval;
data_len (7 downto 0) <= x"00";
elsif (set_len_L = '1') then
-- compute data length, taking into account that we need to subtract the header length
data_len <= std_logic_vector(unsigned(data_len(15 downto 8) & dataval) - 20);
else
data_len <= data_len;
end if;
 
case set_ip_rx_start is
when SET => ip_rx_start_reg <= '1';
when CLR => ip_rx_start_reg <= '0';
when HOLD => ip_rx_start_reg <= ip_rx_start_reg;
end case;
 
case set_is_broadcast is
when SET => is_broadcast_reg <= '1';
when CLR => is_broadcast_reg <= '0';
when HOLD => is_broadcast_reg <= is_broadcast_reg;
end case;
 
case set_hdr_valid is
when SET => hdr_valid_reg <= '1';
when CLR => hdr_valid_reg <= '0';
when HOLD => hdr_valid_reg <= hdr_valid_reg;
end case;
 
-- set error code
if set_error_code = '1' then
error_code_reg <= error_code_val;
else
error_code_reg <= error_code_reg;
end if;
end if;
end if;
end process;
 
end Behavioral;
 
----------------------------------------------------------------------------------
-- Company:
-- Engineer: Peter Fall
--
-- Create Date: 16:20:42 06/01/2011
-- Design Name:
-- Module Name: IPv4_RX - Behavioral
-- Project Name:
-- Target Devices:
-- Tool versions:
-- Description:
-- handle simple IP RX
-- doesnt handle reassembly
-- checks and filters for IP protocol
-- checks and filters for IP addr
-- Handle IPv4 protocol
-- Dependencies:
--
-- Revision:
-- Revision 0.01 - File Created
-- Revision 0.02 - Improved error handling
-- Revision 0.03 - Added handling of broadcast address
-- Additional Comments:
--
----------------------------------------------------------------------------------
library IEEE;
use IEEE.STD_LOGIC_1164.all;
use IEEE.NUMERIC_STD.all;
use work.axi.all;
use work.ipv4_types.all;
use work.arp_types.all;
 
entity IPv4_RX is
port (
-- IP Layer signals
ip_rx : out ipv4_rx_type;
ip_rx_start : out std_logic; -- indicates receipt of ip frame.
-- system signals
clk : in std_logic; -- same clock used to clock mac data and ip data
reset : in std_logic;
our_ip_address : in std_logic_vector (31 downto 0);
rx_pkt_count : out std_logic_vector(7 downto 0); -- number of IP pkts received for us
-- MAC layer RX signals
mac_data_in : in std_logic_vector (7 downto 0); -- ethernet frame (from dst mac addr through to last byte of frame)
mac_data_in_valid : in std_logic; -- indicates data_in valid on clock
mac_data_in_last : in std_logic -- indicates last data in frame
);
end IPv4_RX;
 
architecture Behavioral of IPv4_RX is
 
type rx_state_type is (IDLE, ETH_HDR, IP_HDR, USER_DATA, WAIT_END, ERR);
 
type rx_event_type is (NO_EVENT, DATA);
type count_mode_type is (RST, INCR, HOLD);
type settable_count_mode_type is (RST, INCR, SET_VAL, HOLD);
type set_clr_type is (SET, CLR, HOLD);
 
 
-- state variables
signal rx_state : rx_state_type;
signal rx_count : unsigned (15 downto 0);
signal src_ip : std_logic_vector (31 downto 0); -- src IP captured from input
signal dst_ip : std_logic_vector (23 downto 0); -- 1st 3 bytes of dst IP captured from input
signal is_broadcast_reg : std_logic;
signal protocol : std_logic_vector (7 downto 0); -- src protocol captured from input
signal data_len : std_logic_vector (15 downto 0); -- src data length captured from input
signal ip_rx_start_reg : std_logic; -- indicates start of user data
signal hdr_valid_reg : std_logic; -- indicates that hdr data is valid
signal frame_err_cnt : unsigned (7 downto 0); -- number of frame errors
signal error_code_reg : std_logic_vector (3 downto 0);
signal rx_pkt_counter : unsigned (7 downto 0); -- number of rx frames received for us
 
-- rx control signals
signal next_rx_state : rx_state_type;
signal set_rx_state : std_logic;
signal rx_event : rx_event_type;
signal rx_count_mode : settable_count_mode_type;
signal set_dst_ip3 : std_logic;
signal set_dst_ip2 : std_logic;
signal set_dst_ip1 : std_logic;
signal set_ip3 : std_logic;
signal set_ip2 : std_logic;
signal set_ip1 : std_logic;
signal set_ip0 : std_logic;
signal set_protocol : std_logic;
signal set_len_H : std_logic;
signal set_len_L : std_logic;
signal set_ip_rx_start : set_clr_type;
signal set_hdr_valid : set_clr_type;
signal set_frame_err_cnt : count_mode_type;
signal dataval : std_logic_vector (7 downto 0);
signal rx_count_val : unsigned (15 downto 0);
signal set_error_code : std_logic;
signal error_code_val : std_logic_vector (3 downto 0);
signal set_pkt_cnt : count_mode_type;
signal set_data_last : std_logic;
signal dst_ip_rx : std_logic_vector (31 downto 0);
signal set_is_broadcast : set_clr_type;
 
 
-- IP datagram header format
--
-- 0 4 8 16 19 24 31
-- --------------------------------------------------------------------------------------------
-- | Version | *Header | Service Type | Total Length including header |
-- | (4) | Length | (ignored) | (in bytes) |
-- --------------------------------------------------------------------------------------------
-- | Identification | Flags | Fragment Offset |
-- | | | (in 32 bit words) |
-- --------------------------------------------------------------------------------------------
-- | Time To Live | Protocol | Header Checksum |
-- | (ignored) | | |
-- --------------------------------------------------------------------------------------------
-- | Source IP Address |
-- | |
-- --------------------------------------------------------------------------------------------
-- | Destination IP Address |
-- | |
-- --------------------------------------------------------------------------------------------
-- | Options (if any - ignored) | Padding |
-- | | (if needed) |
-- --------------------------------------------------------------------------------------------
-- | Data |
-- | |
-- --------------------------------------------------------------------------------------------
-- | .... |
-- | |
-- --------------------------------------------------------------------------------------------
--
-- * - in 32 bit words
begin
 
-----------------------------------------------------------------------
-- combinatorial process to implement FSM and determine control signals
-----------------------------------------------------------------------
 
rx_combinatorial : process (
-- input signals
mac_data_in, mac_data_in_valid, mac_data_in_last, our_ip_address,
-- state variables
rx_state, rx_count, src_ip, dst_ip, protocol, data_len, ip_rx_start_reg, hdr_valid_reg,
frame_err_cnt, error_code_reg, rx_pkt_counter, is_broadcast_reg,
-- control signals
next_rx_state, set_rx_state, rx_event, rx_count_mode,
set_ip3, set_ip2, set_ip1, set_ip0, set_protocol, set_len_H, set_len_L,
set_dst_ip3, set_dst_ip2, set_dst_ip1,
set_ip_rx_start, set_hdr_valid, set_frame_err_cnt, dataval, rx_count_val,
set_error_code, error_code_val, set_pkt_cnt, set_data_last, dst_ip_rx, set_is_broadcast
)
begin
-- set output followers
ip_rx_start <= ip_rx_start_reg;
ip_rx.hdr.is_valid <= hdr_valid_reg;
ip_rx.hdr.protocol <= protocol;
ip_rx.hdr.data_length <= data_len;
ip_rx.hdr.src_ip_addr <= src_ip;
ip_rx.hdr.num_frame_errors <= std_logic_vector(frame_err_cnt);
ip_rx.hdr.last_error_code <= error_code_reg;
ip_rx.hdr.is_broadcast <= is_broadcast_reg;
rx_pkt_count <= std_logic_vector(rx_pkt_counter);
 
-- transfer data upstream if in user data phase
if rx_state = USER_DATA then
ip_rx.data.data_in <= mac_data_in;
ip_rx.data.data_in_valid <= mac_data_in_valid;
ip_rx.data.data_in_last <= set_data_last;
else
ip_rx.data.data_in <= (others => '0');
ip_rx.data.data_in_valid <= '0';
ip_rx.data.data_in_last <= '0';
end if;
 
-- set signal defaults
next_rx_state <= IDLE;
set_rx_state <= '0';
rx_event <= NO_EVENT;
rx_count_mode <= HOLD;
set_ip3 <= '0';
set_ip2 <= '0';
set_ip1 <= '0';
set_ip0 <= '0';
set_dst_ip3 <= '0';
set_dst_ip2 <= '0';
set_dst_ip1 <= '0';
set_protocol <= '0';
set_len_H <= '0';
set_len_L <= '0';
set_ip_rx_start <= HOLD;
set_hdr_valid <= HOLD;
set_frame_err_cnt <= HOLD;
rx_count_val <= x"0000";
set_error_code <= '0';
error_code_val <= RX_EC_NONE;
set_pkt_cnt <= HOLD;
dataval <= (others => '0');
set_data_last <= '0';
dst_ip_rx <= (others => '0');
set_is_broadcast <= HOLD;
 
-- determine event (if any)
if mac_data_in_valid = '1' then
rx_event <= DATA;
dataval <= mac_data_in;
end if;
 
-- RX FSM
case rx_state is
when IDLE =>
rx_count_mode <= RST;
case rx_event is
when NO_EVENT => -- (nothing to do)
when DATA =>
rx_count_mode <= INCR;
set_hdr_valid <= CLR;
next_rx_state <= ETH_HDR;
set_rx_state <= '1';
end case;
 
when ETH_HDR =>
case rx_event is
when NO_EVENT => -- (nothing to do)
when DATA =>
if rx_count = x"000d" then
rx_count_mode <= RST;
next_rx_state <= IP_HDR;
set_rx_state <= '1';
else
rx_count_mode <= INCR;
end if;
-- handle early frame termination
if mac_data_in_last = '1' then
error_code_val <= RX_EC_ET_ETH;
set_error_code <= '1';
set_frame_err_cnt <= INCR;
set_ip_rx_start <= CLR;
set_data_last <= '1';
next_rx_state <= IDLE;
rx_count_mode <= RST;
set_rx_state <= '1';
else
case rx_count is
when x"000c" =>
if mac_data_in /= x"08" then -- ignore pkts that are not type=IP
next_rx_state <= WAIT_END;
set_rx_state <= '1';
end if;
when x"000d" =>
if mac_data_in /= x"00" then -- ignore pkts that are not type=IP
next_rx_state <= WAIT_END;
set_rx_state <= '1';
end if;
when others => -- ignore other bytes in eth header
end case;
end if;
end case;
 
when IP_HDR =>
case rx_event is
when NO_EVENT => -- (nothing to do)
when DATA =>
if rx_count = x"0013" then
rx_count_val <= x"0001"; -- start counter at 1
rx_count_mode <= SET_VAL;
else
rx_count_mode <= INCR;
end if;
-- handle early frame termination
if mac_data_in_last = '1' then
error_code_val <= RX_EC_ET_IP;
set_error_code <= '1';
set_frame_err_cnt <= INCR;
set_ip_rx_start <= CLR;
set_data_last <= '1';
next_rx_state <= IDLE;
rx_count_mode <= RST;
set_rx_state <= '1';
else
case rx_count is
when x"0000" =>
if mac_data_in /= x"45" then -- ignore pkts that are not v4 with 5 header words
next_rx_state <= WAIT_END;
set_rx_state <= '1';
end if;
when x"0002" => set_len_H <= '1';
when x"0003" => set_len_L <= '1';
 
when x"0006" =>
if (mac_data_in(7) = '1') or (mac_data_in (4 downto 0) /= "00000") then
-- ignore pkts that require reassembly (MF=1 or frag offst /= 0)
next_rx_state <= WAIT_END;
set_rx_state <= '1';
end if;
when x"0007" =>
if mac_data_in /= x"00" then -- ignore pkts that require reassembly (frag offst /= 0)
next_rx_state <= WAIT_END;
set_rx_state <= '1';
end if;
 
when x"0009" => set_protocol <= '1';
 
when x"000c" => set_ip3 <= '1';
when x"000d" => set_ip2 <= '1';
when x"000e" => set_ip1 <= '1';
when x"000f" => set_ip0 <= '1';
 
when x"0010" => set_dst_ip3 <= '1';
if ((mac_data_in /= our_ip_address(31 downto 24)) and
(mac_data_in /= IP_BC_ADDR(31 downto 24)))then -- ignore pkts that are not addressed to us
next_rx_state <= WAIT_END;
set_rx_state <= '1';
end if;
when x"0011" => set_dst_ip2 <= '1';
if ((mac_data_in /= our_ip_address(23 downto 16)) and
(mac_data_in /= IP_BC_ADDR(23 downto 16)))then -- ignore pkts that are not addressed to us
next_rx_state <= WAIT_END;
set_rx_state <= '1';
end if;
when x"0012" => set_dst_ip1 <= '1';
if ((mac_data_in /= our_ip_address(15 downto 8)) and
(mac_data_in /= IP_BC_ADDR(15 downto 8)))then -- ignore pkts that are not addressed to us
next_rx_state <= WAIT_END;
set_rx_state <= '1';
end if;
 
when x"0013" =>
if ((mac_data_in /= our_ip_address(7 downto 0)) and
(mac_data_in /= IP_BC_ADDR(7 downto 0)))then -- ignore pkts that are not addressed to us
next_rx_state <= WAIT_END;
set_rx_state <= '1';
else
next_rx_state <= USER_DATA;
set_pkt_cnt <= INCR; -- count another pkt
set_rx_state <= '1';
set_ip_rx_start <= SET;
end if;
 
-- now have the dst IP addr
dst_ip_rx <= dst_ip & mac_data_in;
if dst_ip_rx = IP_BC_ADDR then
set_is_broadcast <= SET;
else
set_is_broadcast <= CLR;
end if;
set_hdr_valid <= SET; -- header values are now valid, although the pkt may not be for us
 
--if dst_ip_rx = our_ip_address or dst_ip_rx = IP_BC_ADDR then
-- next_rx_state <= USER_DATA;
-- set_pkt_cnt <= INCR; -- count another pkt received
-- set_rx_state <= '1';
-- set_ip_rx_start <= SET;
--else
-- next_rx_state <= WAIT_END;
-- set_rx_state <= '1';
--end if;
when others => -- ignore other bytes in ip header
end case;
end if;
end case;
when USER_DATA =>
case rx_event is
when NO_EVENT => -- (nothing to do)
when DATA =>
-- note: data gets transfered upstream as part of "output followers" processing
if rx_count = unsigned(data_len) then
set_ip_rx_start <= CLR;
rx_count_mode <= RST;
set_data_last <= '1';
if mac_data_in_last = '1' then
next_rx_state <= IDLE;
rx_count_mode <= RST;
set_ip_rx_start <= CLR;
else
next_rx_state <= WAIT_END;
end if;
set_rx_state <= '1';
else
rx_count_mode <= INCR;
-- check for early frame termination
if mac_data_in_last = '1' then
error_code_val <= RX_EC_ET_USER;
set_error_code <= '1';
set_frame_err_cnt <= INCR;
set_ip_rx_start <= CLR;
next_rx_state <= IDLE;
rx_count_mode <= RST;
set_rx_state <= '1';
end if;
end if;
end case;
 
when ERR =>
set_frame_err_cnt <= INCR;
set_ip_rx_start <= CLR;
if mac_data_in_last = '0' then
set_data_last <= '1';
next_rx_state <= WAIT_END;
set_rx_state <= '1';
else
next_rx_state <= IDLE;
rx_count_mode <= RST;
set_rx_state <= '1';
end if;
 
when WAIT_END =>
case rx_event is
when NO_EVENT => -- (nothing to do)
when DATA =>
if mac_data_in_last = '1' then
set_data_last <= '1';
next_rx_state <= IDLE;
rx_count_mode <= RST;
set_rx_state <= '1';
set_ip_rx_start <= CLR;
end if;
end case;
end case;
end process;
 
 
-----------------------------------------------------------------------------
-- sequential process to action control signals and change states and outputs
-----------------------------------------------------------------------------
 
rx_sequential : process (clk)--, reset)
begin
if rising_edge(clk) then
if reset = '1' then
-- reset state variables
rx_state <= IDLE;
rx_count <= x"0000";
src_ip <= (others => '0');
dst_ip <= (others => '0');
protocol <= (others => '0');
data_len <= (others => '0');
ip_rx_start_reg <= '0';
hdr_valid_reg <= '0';
is_broadcast_reg <= '0';
frame_err_cnt <= (others => '0');
error_code_reg <= RX_EC_NONE;
rx_pkt_counter <= x"00";
 
else
-- Next rx_state processing
if set_rx_state = '1' then
rx_state <= next_rx_state;
else
rx_state <= rx_state;
end if;
 
-- rx_count processing
case rx_count_mode is
when RST => rx_count <= x"0000";
when INCR => rx_count <= rx_count + 1;
when SET_VAL => rx_count <= rx_count_val;
when HOLD => rx_count <= rx_count;
end case;
 
-- frame error count processing
case set_frame_err_cnt is
when RST => frame_err_cnt <= x"00";
when INCR => frame_err_cnt <= frame_err_cnt + 1;
when HOLD => frame_err_cnt <= frame_err_cnt;
end case;
 
-- ip pkt processing
case set_pkt_cnt is
when RST => rx_pkt_counter <= x"00";
when INCR => rx_pkt_counter <= rx_pkt_counter + 1;
when HOLD => rx_pkt_counter <= rx_pkt_counter;
end case;
 
-- source ip capture
if (set_ip3 = '1') then src_ip(31 downto 24) <= dataval; end if;
if (set_ip2 = '1') then src_ip(23 downto 16) <= dataval; end if;
if (set_ip1 = '1') then src_ip(15 downto 8) <= dataval; end if;
if (set_ip0 = '1') then src_ip(7 downto 0) <= dataval; end if;
 
-- dst ip capture
if (set_dst_ip3 = '1') then dst_ip(23 downto 16) <= dataval; end if;
if (set_dst_ip2 = '1') then dst_ip(15 downto 8) <= dataval; end if;
if (set_dst_ip1 = '1') then dst_ip(7 downto 0) <= dataval; end if;
 
if (set_protocol = '1') then
protocol <= dataval;
else
protocol <= protocol;
end if;
 
if (set_len_H = '1') then
data_len (15 downto 8) <= dataval;
data_len (7 downto 0) <= x"00";
elsif (set_len_L = '1') then
-- compute data length, taking into account that we need to subtract the header length
data_len <= std_logic_vector(unsigned(data_len(15 downto 8) & dataval) - 20);
else
data_len <= data_len;
end if;
 
case set_ip_rx_start is
when SET => ip_rx_start_reg <= '1';
when CLR => ip_rx_start_reg <= '0';
when HOLD => ip_rx_start_reg <= ip_rx_start_reg;
end case;
 
case set_is_broadcast is
when SET => is_broadcast_reg <= '1';
when CLR => is_broadcast_reg <= '0';
when HOLD => is_broadcast_reg <= is_broadcast_reg;
end case;
 
case set_hdr_valid is
when SET => hdr_valid_reg <= '1';
when CLR => hdr_valid_reg <= '0';
when HOLD => hdr_valid_reg <= hdr_valid_reg;
end case;
 
-- set error code
if set_error_code = '1' then
error_code_reg <= error_code_val;
else
error_code_reg <= error_code_reg;
end if;
end if;
end if;
end process;
 
end Behavioral;
 

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