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[/] [udp_ip_stack/] [tags/] [v2.0/] [rtl/] [vhdl/] [arp_RX.vhd] - Rev 37
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---------------------------------------------------------------------------------- -- Company: -- Engineer: Peter Fall -- -- Create Date: 12:00:04 05/31/2011 -- Design Name: -- Module Name: arp_rx - Behavioral -- Project Name: -- Target Devices: -- Tool versions: -- Description: -- handle receipt of arp pkt -- ignores other types of pkt -- -- When it receives an ARP pkt that is either addressed to our IP or is a global request, -- it outputs for a single clock cycle either recv_who_has or recv_I_have along -- with associated mac or arp entry data. -- -- Note that if recv who_has and we have it, then we also assert I_have so that we can cache the rev lookup -- on the expectation that we will want to reply to this host. -- -- Dependencies: -- -- Revision: -- Revision 0.01 - File Created - refactored from arp v0.02 module -- Additional Comments: -- ---------------------------------------------------------------------------------- library IEEE; use IEEE.STD_LOGIC_1164.ALL; use IEEE.NUMERIC_STD.ALL; use work.arp_types.all; entity arp_rx is Port ( -- MAC layer RX signals data_in : in STD_LOGIC_VECTOR (7 downto 0); -- ethernet frame (from dst mac addr through to last byte of frame) data_in_valid : in STD_LOGIC; -- indicates data_in valid on clock data_in_last : in STD_LOGIC; -- indicates last data in frame -- ARP output signals recv_who_has : out std_logic; -- pulse will be latched arp_entry_for_who_has : out arp_entry_t; -- target for who_has msg (Iie, who to reply to) recv_I_have : out std_logic; -- pulse will be latched arp_entry_for_I_have : out arp_entry_t; -- arp target for I_have msg -- control and status signals req_count : out STD_LOGIC_VECTOR(7 downto 0); -- count of arp pkts received -- system signals our_ip_address : in STD_LOGIC_VECTOR (31 downto 0); rx_clk : in std_logic; reset : in STD_LOGIC ); end arp_rx; architecture Behavioral of arp_rx is type rx_state_t is (IDLE,PARSE,PROCESS_ARP,WAIT_END); type rx_event_t is (NO_EVENT,DATA); type count_mode_t is (RST,INCR,HOLD); type arp_oper_t is (NOP,REQUEST,REPLY); type tx_state_type is (IDLE,WAIT_MAC,SEND); -- state variables signal send_request_needed : std_logic; signal tx_mac_chn_reqd : std_logic; signal rx_state : rx_state_t; signal rx_count : unsigned (7 downto 0); signal arp_operation : arp_oper_t; signal arp_req_count : unsigned (7 downto 0); signal new_arp_entry : arp_entry_t; -- FIXME - remove these debug state signals signal arp_err_data : std_logic_vector (7 downto 0); signal set_err_data : std_logic; attribute keep : string; attribute keep of arp_err_data : signal is "true"; -- rx control signals signal next_rx_state : rx_state_t; signal set_rx_state : std_logic; signal rx_event : rx_event_t; signal rx_count_mode : count_mode_t; signal set_arp_oper : std_logic; signal arp_oper_set_val : arp_oper_t; signal dataval : std_logic_vector (7 downto 0); signal count_arp_rcvd : std_logic; signal set_mac5 : std_logic; signal set_mac4 : std_logic; signal set_mac3 : std_logic; signal set_mac2 : std_logic; signal set_mac1 : std_logic; signal set_mac0 : std_logic; signal set_ip3 : std_logic; signal set_ip2 : std_logic; signal set_ip1 : std_logic; signal set_ip0 : std_logic; -- function to determine whether the rx pkt is an arp pkt and whether we want to process it -- Returns 1 if we should discard -- The following will make us ignore the frame (all values hexadecimal): -- PDU type /= 0806 -- Protocol Type /= 0800 -- Hardware Type /= 1 -- Hardware Length /= 6 -- Protocol Length /= 4 -- Operation /= 1 or 2 -- Target IP /= our IP (i.er. message is not meant for us) -- function not_our_arp(data : STD_LOGIC_VECTOR; count : unsigned; our_ip : std_logic_vector) return std_logic is begin if (count = 12 and data /= x"08") or -- PDU type 0806 : ARP (count = 13 and data /= x"06") or (count = 14 and data /= x"00") or -- HW type 1 : eth (count = 15 and data /= x"01") or (count = 16 and data /= x"08") or -- Protocol 0800 : IP (count = 17 and data /= x"00") or (count = 18 and data /= x"06") or -- HW Length 6 (count = 19 and data /= x"04") or -- protocol length 4 (count = 20 and data /= x"00") or -- operation 1 or 2 (req or reply) (count = 21 and data /= x"01" and data /= x"02") or (count = 38 and data /= our_ip(31 downto 24)) or -- target IP is ours (count = 39 and data /= our_ip(23 downto 16)) or (count = 40 and data /= our_ip(15 downto 8)) or (count = 41 and data /= our_ip(7 downto 0)) then return '1'; else return '0'; end if; end function not_our_arp; begin rx_combinatorial : process ( -- input signals data_in, data_in_valid, data_in_last, our_ip_address, -- state variables rx_state, rx_count, arp_operation, arp_req_count, arp_err_data, new_arp_entry, -- control signals next_rx_state, set_rx_state, rx_event, rx_count_mode, set_arp_oper, arp_oper_set_val, dataval,set_mac5,set_mac4,set_mac3,set_mac2,set_mac1,set_mac0,set_ip3,set_ip2,set_ip1,set_ip0, set_err_data, count_arp_rcvd ) begin -- set output followers req_count <= STD_LOGIC_VECTOR(arp_req_count); -- set defaults for combinatorial outputs recv_who_has <= '0'; arp_entry_for_who_has.ip <= (others => '0'); arp_entry_for_who_has.mac <= (others => '0'); recv_I_have <= '0'; arp_entry_for_I_have.ip <= (others => '0'); arp_entry_for_I_have.mac <= (others => '0'); -- set signal defaults next_rx_state <= IDLE; set_rx_state <= '0'; rx_event <= NO_EVENT; rx_count_mode <= HOLD; set_arp_oper <= '0'; arp_oper_set_val <= NOP; dataval <= (others => '0'); set_mac5 <= '0'; set_mac4 <= '0'; set_mac3 <= '0'; set_mac2 <= '0'; set_mac1 <= '0'; set_mac0 <= '0'; set_ip3 <= '0'; set_ip2 <= '0'; set_ip1 <= '0'; set_ip0 <= '0'; count_arp_rcvd <= '0'; set_err_data <= '0'; -- determine event (if any) if data_in_valid = '1' then rx_event <= DATA; 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 => next_rx_state <= PARSE; set_rx_state <= '1'; rx_count_mode <= INCR; end case; when PARSE => case rx_event is when NO_EVENT => -- (nothing to do) when DATA => rx_count_mode <= INCR; -- handle early frame termination if data_in_last = '1' then next_rx_state <= IDLE; set_rx_state <= '1'; else -- check for end of frame. Also, detect and discard if not our frame if rx_count = 42 then next_rx_state <= PROCESS_ARP; set_rx_state <= '1'; elsif not_our_arp(data_in,rx_count,our_ip_address) = '1' then dataval <= data_in; set_err_data <= '1'; next_rx_state <= WAIT_END; set_rx_state <= '1'; elsif rx_count = 21 then -- capture ARP operation case data_in is when x"01" => arp_oper_set_val <= REQUEST; set_arp_oper <= '1'; when x"02" => arp_oper_set_val <= REPLY; set_arp_oper <= '1'; when others => -- ignore other values end case; -- capture source mac addr elsif rx_count = 22 then set_mac5 <= '1'; dataval <= data_in; elsif rx_count = 23 then set_mac4 <= '1'; dataval <= data_in; elsif rx_count = 24 then set_mac3 <= '1'; dataval <= data_in; elsif rx_count = 25 then set_mac2 <= '1'; dataval <= data_in; elsif rx_count = 26 then set_mac1 <= '1'; dataval <= data_in; elsif rx_count = 27 then set_mac0 <= '1'; dataval <= data_in; -- capture source ip addr elsif rx_count = 28 then set_ip3 <= '1'; dataval <= data_in; elsif rx_count = 29 then set_ip2 <= '1'; dataval <= data_in; elsif rx_count = 30 then set_ip1 <= '1'; dataval <= data_in; elsif rx_count = 31 then set_ip0 <= '1'; dataval <= data_in; end if; end if; end case; when PROCESS_ARP => next_rx_state <= WAIT_END; set_rx_state <= '1'; arp_oper_set_val <= NOP; set_arp_oper <= '1'; case arp_operation is when NOP => -- (nothing to do) when REQUEST => count_arp_rcvd <= '1'; recv_who_has <= '1'; arp_entry_for_who_has <= new_arp_entry; -- setting I_Have as well allows us to cache the remote node's entry immediately recv_I_have <= '1'; arp_entry_for_I_have <= new_arp_entry; when REPLY => count_arp_rcvd <= '1'; recv_I_have <= '1'; arp_entry_for_I_have <= new_arp_entry; end case; when WAIT_END => case rx_event is when NO_EVENT => -- (nothing to do) when DATA => if data_in_last = '1' then next_rx_state <= IDLE; set_rx_state <= '1'; end if; end case; end case; end process; rx_sequential : process (rx_clk) begin if rising_edge(rx_clk) then if reset = '1' then -- reset state variables rx_state <= IDLE; rx_count <= x"00"; arp_operation <= NOP; arp_req_count <= x"00"; arp_err_data <= (others => '0'); 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"00"; when INCR => rx_count <= rx_count + 1; when HOLD => rx_count <= rx_count; end case; -- err data if set_err_data = '1' then arp_err_data <= data_in; else arp_err_data <= arp_err_data; end if; -- arp operation processing if set_arp_oper = '1' then arp_operation <= arp_oper_set_val; else arp_operation <= arp_operation; end if; -- source mac capture if (set_mac5 = '1') then new_arp_entry.mac(47 downto 40) <= dataval; end if; if (set_mac4 = '1') then new_arp_entry.mac(39 downto 32) <= dataval; end if; if (set_mac3 = '1') then new_arp_entry.mac(31 downto 24) <= dataval; end if; if (set_mac2 = '1') then new_arp_entry.mac(23 downto 16) <= dataval; end if; if (set_mac1 = '1') then new_arp_entry.mac(15 downto 8) <= dataval; end if; if (set_mac0 = '1') then new_arp_entry.mac(7 downto 0) <= dataval; end if; -- source ip capture if (set_ip3 = '1') then new_arp_entry.ip(31 downto 24) <= dataval; end if; if (set_ip2 = '1') then new_arp_entry.ip(23 downto 16) <= dataval; end if; if (set_ip1 = '1') then new_arp_entry.ip(15 downto 8) <= dataval; end if; if (set_ip0 = '1') then new_arp_entry.ip(7 downto 0) <= dataval; end if; -- set arp entry request if count_arp_rcvd = '1' then -- count another ARP pkt received arp_req_count <= arp_req_count + 1; else arp_req_count <= arp_req_count; end if; end if; end if; end process; end Behavioral;
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