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arp: Implement ARP requests

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This is still missing timeout in case of no reply.
This needs to be added!
This commit is contained in:
Markus Koch 2022-10-28 18:52:17 +02:00
parent 1a41120afa
commit 4804674d8e
3 changed files with 110 additions and 26 deletions
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115
trashernet/trashernet_arp.vhd
View File

@ -43,11 +43,78 @@ architecture rtl of trashernet_arp is
constant OPER_REQUEST : byte_vector := (x"00", x"01");
constant OPER_REPLY : byte_vector := (x"00", x"02");
signal arp_reply_rq : std_logic; -- Request to transmit an ARP reply
signal arp_reply_tha : mac_addr_t; -- Target MAC to use in reply (SHA in received packet)
signal arp_reply_tpa : ip_addr_t; -- Target IP to use in reply (SPA in received packet)
signal arp_reply_ack : std_logic; -- ARP reply has been latched and is being sent
signal arp_tx_reply_rq : std_logic; -- Request to transmit an ARP reply
signal arp_tx_reply_tha : mac_addr_t; -- Target MAC to use in reply (SHA in received packet)
signal arp_tx_reply_tpa : ip_addr_t; -- Target IP to use in reply (SPA in received packet)
signal arp_tx_reply_ack : std_logic; -- ARP reply has been latched and is being sent
signal arp_tx_request_rq : std_logic; -- Request to transmit an ARP request
signal arp_tx_request_tpa : ip_addr_t; -- IP address that we want to know the MAC address of
signal arp_tx_request_ack : std_logic; -- ARP request has been latched and is being sent
signal arp_rx_reply_stb : std_logic; -- An ARP reply was received (strobe)
signal arp_rx_sha : mac_addr_t; -- The MAC address of the reply sender, valid with arp_rx_reply
signal arp_rx_spa : ip_addr_t; -- The IP address of the reply sender, valid with arp_rx_reply
begin
resolver : block
type resolver_state_t is (IDLE, QUERY_MAC);
signal state : resolver_state_t;
signal query_mac_found : std_logic;
signal query_timeout : std_logic := '0'; -- TODO: Implement
signal replied_ip : ip_addr_t;
signal replied_mac : mac_addr_t;
begin
arp_resolver_main : process(rst, clk) is
begin
if rst then
state <= IDLE;
replied_ip <= (others => x"00"); -- 0.0.0.0
arp_out.arp_ok_stb <= '0';
arp_out.arp_fail_stb <= '0';
arp_tx_request_rq <= '0';
elsif rising_edge(clk) then
arp_out.arp_ok_stb <= '0';
arp_out.arp_fail_stb <= '0';
if arp_rx_reply_stb then
if arp_tx_request_tpa = arp_rx_spa then -- If this reply is actually for our request
replied_mac <= arp_rx_sha;
replied_ip <= arp_rx_spa;
end if;
end if;
case state is
when IDLE =>
if arp_in.arp_query_stb then
if query_mac_found then
arp_out.arp_ok_stb <= '1';
else
arp_tx_request_rq <= '1';
state <= QUERY_MAC;
end if;
end if;
when QUERY_MAC =>
if arp_tx_request_ack then
arp_tx_request_rq <= '0';
end if;
if query_mac_found or query_timeout then
arp_out.arp_ok_stb <= query_mac_found;
arp_out.arp_fail_stb <= not query_mac_found;
state <= IDLE;
end if;
end case;
end if;
end process arp_resolver_main;
query_mac_found <= '1' when (arp_tx_request_tpa = replied_ip) else '0';
arp_out.arp_mac <= replied_mac;
arp_tx_request_tpa <= arp_in.arp_ip;
end block resolver;
rx : block
constant BYTECOUNT_HEAD : integer := 8; -- HTYPE -> OPER
constant BYTECOUNT_ADDRESSES : integer := 20; -- SHA -> TPA
@ -99,8 +166,11 @@ begin
state <= HEAD;
shifted <= '0';
bytecount <= BYTECOUNT_HEAD;
arp_rx_reply_stb <= '0';
elsif rising_edge(clk) then
arp_rx_reply_stb <= '0';
if (ethernet_ii_out.rx_crc_ok or ethernet_ii_out.rx_crc_error) then
state <= HEAD; -- Safe return from any state, may be overridden below
bytecount <= BYTECOUNT_HEAD;
@ -136,13 +206,12 @@ begin
if is_request then
state <= SENDREPLY;
else
report "reply";
null; -- TODO: process response
arp_rx_reply_stb <= '1';
end if;
end if;
when SENDREPLY =>
if arp_reply_ack then
if arp_tx_reply_ack then
bytecount <= BYTECOUNT_HEAD;
state <= HEAD;
end if;
@ -152,14 +221,17 @@ begin
end case;
end if;
end process rx_fsm;
arp_reply_rq <= '1' when state = SENDREPLY else '0';
arp_reply_tha <= sr_addresses_sha;
arp_reply_tpa <= sr_addresses_spa;
arp_tx_reply_rq <= '1' when state = SENDREPLY else '0';
arp_tx_reply_tha <= sr_addresses_sha;
arp_tx_reply_tpa <= sr_addresses_spa;
arp_rx_sha <= sr_addresses_sha;
arp_rx_spa <= sr_addresses_spa;
end block rx;
tx : block
signal sr : byte_vector(0 to 27);
signal arp_reply_preload : byte_vector(sr'range);
signal arp_request_preload : byte_vector(sr'range);
constant BYTECOUNT_MAX : integer := sr'length + 1;
signal bytecount : integer range 0 to BYTECOUNT_MAX;
@ -169,15 +241,21 @@ begin
arp_reply_preload <= HTYPE & PTYPE & HLEN & PLEN & OPER_REPLY & -- Header
mac_config.mac_address & ip_config.ip_address & -- Sender
arp_reply_tha & arp_reply_tpa; -- Target
arp_tx_reply_tha & arp_tx_reply_tpa; -- Target
arp_request_preload <= HTYPE & PTYPE & HLEN & PLEN & OPER_REQUEST & -- Header
mac_config.mac_address & ip_config.ip_address & -- Sender
mac_addr_t'(x"00", x"00", x"00", x"00", x"00", x"00") & arp_tx_request_tpa; -- Target
tx_fsm : process(clk, rst) is
begin
if rst then
arp_reply_ack <= '0';
arp_tx_reply_ack <= '0';
arp_tx_request_ack <= '0';
elsif rising_edge(clk) then
arp_reply_ack <= '0';
arp_tx_reply_ack <= '0';
arp_tx_request_ack <= '0';
if (ethernet_ii_out.tx_data_ack = '1') and (bytecount > 0) then
sr <= sr(sr'low + 1 to sr'high) & x"00";
@ -186,10 +264,16 @@ begin
case state is
when IDLE =>
if arp_reply_rq then
if arp_tx_reply_rq then
state <= TRANSMIT;
arp_reply_ack <= '1';
arp_tx_reply_ack <= '1';
sr <= arp_reply_preload;
ethernet_ii_in.tx_mac_address <= arp_tx_reply_tha;
elsif arp_tx_request_rq then
state <= TRANSMIT;
arp_tx_request_ack <= '1';
sr <= arp_request_preload;
ethernet_ii_in.tx_mac_address <= MAC_ADDR_BROADCAST;
end if;
bytecount <= BYTECOUNT_MAX;
@ -202,7 +286,6 @@ begin
end if;
end process tx_fsm;
ethernet_ii_in.tx_mac_address <= arp_reply_tha;
ethernet_ii_in.tx_en <= '1' when state = TRANSMIT else '0';
ethernet_ii_in.tx_data <= sr(0);

2
trashernet/trashernet_eth.vhd
View File

@ -54,7 +54,7 @@ begin
begin
mac_destination_matches <= '1' when --
((mac_out.rx_header.mac_destination = (x"FF", x"FF", x"FF", x"FF", x"FF", x"FF")) or --
((mac_out.rx_header.mac_destination = MAC_ADDR_BROADCAST) or --
(mac_out.rx_header.mac_destination = config.mac_address)) else
'0';

1
trashernet/trashernet_pkg.vhd
View File

@ -19,6 +19,7 @@ package trashernet_pkg is
-- MAC specific types
subtype mac_addr_t is byte_vector(0 to 5);
constant MAC_ADDR_BROADCAST : mac_addr_t := (others => x"FF");
function mac_to_string(constant mac_address : in mac_addr_t) return string;
subtype ethertype_t is byte_vector(0 to 1);