Handle ack in synack, write to pcap

hw/super6502_fpga/src/sub/network_processor/sim/cocotb/tb/tb_top.sv

@@ -99,7 +99,7 @@ assign s_regs_axil_rresp    = regs_axil.rresp;
 
 
 network_processor #(
-    .NUM_TCP(8)
+    .NUM_TCP(4)
 ) u_network_processor (
     .i_clk                  (clk),
     .i_rst                  (rst),

hw/super6502_fpga/src/sub/network_processor/sim/cocotb/tests/tcp_test.py

@@ -8,6 +8,8 @@ import struct
 
 from scapy.layers.inet import Ether, IP, TCP
 from scapy.layers.l2 import ARP
+from scapy.utils import PcapWriter
+
 import logging
 
 from decimal import Decimal
@@ -55,6 +57,9 @@ def ip_to_hex(ip: str) -> int:
 
 @cocotb.test()
 async def test_simple(dut):
+    pktdump = PcapWriter("tcp.pcap", append=True, sync=True)
+
+
     tb = TB(dut)
 
     await tb.cycle_reset()
@@ -78,6 +83,7 @@ async def test_simple(dut):
     resp = await tb.mii_phy.tx.recv() # type: GmiiFrame
 
     packet = Ether(resp.get_payload())
+    pktdump.write(packet)
 
     tb.log.info(f"Packet Type: {packet.type:x}")
 
@@ -106,10 +112,15 @@ async def test_simple(dut):
     arp_response /= ARP(op="is-at", hwsrc=tb_mac, hwdst=dut_mac, psrc=tb_ip, pdst=dut_ip)
     arp_response = arp_response.build()
 
+    pktdump.write(arp_response)
+
     await tb.mii_phy.rx.send(GmiiFrame.from_payload(arp_response))
 
+    # 1. DUT sends syn with seq number
+
     resp = await tb.mii_phy.tx.recv() # type: GmiiFrame
     packet = Ether(resp.get_payload())
+    pktdump.write(packet)
     tb.log.info(f"Packet Type: {packet.type:x}")
 
     ip_packet = packet.payload
@@ -129,17 +140,23 @@ async def test_simple(dut):
 
 
     dut_seq = tcp_packet.seq
-    tb_seq = 0x11111111
+    tb_seq = 11111111
+
+    # 2. Send SYNACK with seq as our sequence number, and ACK as their sequence number plus 1
 
     tcp_synack = Ether(dst=dut_mac, src=tb_mac)
     tcp_synack /= IP(src=tb_ip, dst=dut_ip)
     tcp_synack /= TCP(sport=tb_port, dport=dut_port, seq=tb_seq, ack=dut_seq+1, flags="SA")
     tcp_synack = tcp_synack.build()
+    pktdump.write(tcp_synack)
 
     await tb.mii_phy.rx.send(GmiiFrame.from_payload(tcp_synack))
 
+    # 3. Receieve ACK with our sequence number plus 1
+
     resp = await tb.mii_phy.tx.recv() # type: GmiiFrame
     packet = Ether(resp.get_payload())
+    pktdump.write(packet)
     tb.log.info(f"Packet Type: {packet.type:x}")
 
 
@@ -157,3 +174,5 @@ async def test_simple(dut):
     tb.log.info(f"flags: {tcp_packet.flags}")
     tb.log.info(f"window: {tcp_packet.window}")
     tb.log.info(f"Checksum: {tcp_packet.chksum}")
+
+    assert tcp_packet.ack == tb_seq + 1

hw/super6502_fpga/src/sub/network_processor/src/tcp_rx_ctrl.sv

@@ -1,27 +1,42 @@
 import tcp_pkg::*;
 
 module tcp_rx_ctrl (
-    input wire              i_clk,
-    input wire              i_rst,
+    input  logic              i_clk,
+    input  logic              i_rst,
 
     output tcp_pkg::rx_msg_t  o_rx_msg,
     output logic              o_rx_msg_valid,
     input  logic              i_rx_msg_ack,
 
-    input  wire [31:0]      i_seq_number,
-    input  wire [31:0]      i_ack_number,
-    input  wire [15:0]      i_source_port,
-    input  wire [15:0]      i_dest_port,
-    input  wire [7:0]       i_flags,
-    input  wire [15:0]      i_window_size,
-    input  wire             i_hdr_valid
+    input  logic [31:0]       i_seq_number,
+    input  logic [31:0]       i_ack_number,
+    input  logic [15:0]       i_source_port,
+    input  logic [15:0]       i_dest_port,
+    input  logic [7:0]        i_flags,
+    input  logic [15:0]       i_window_size,
+    input  logic              i_hdr_valid,
+
+    output logic [31:0]       o_ack_number
 );
 
+logic [31:0] ack_num, ack_num_next;
+assign o_ack_number = ack_num;
+
 always_ff @(posedge i_clk) begin
+    if (i_rst) begin
+        ack_num <= '0;
+    end else begin
+        ack_num <= ack_num_next;
+    end
+end
+
+always_comb begin
     if (i_hdr_valid) begin
         if (i_flags & 8'h12) begin
             o_rx_msg = RX_MSG_RECV_SYNACK;
             o_rx_msg_valid = '1;
+
+            ack_num_next = i_seq_number + 1;
         end
     end
 end

hw/super6502_fpga/src/sub/network_processor/src/tcp_stream.sv

@@ -178,7 +178,7 @@ tcp_tx_ctrl u_tcp_tx_ctrl (
     .o_tx_ctrl_ack              (tx_ctrl_ack),
 
     .o_seq_number               (w_tx_seq_number),
-    .o_ack_number               (w_tx_ack_number),
+    // .o_ack_number               (w_tx_ack_number),
     .o_flags                    (w_tx_flags),
     .o_window_size              (w_tx_window_size),
     .o_hdr_valid                (w_tx_hdr_valid),
@@ -236,7 +236,9 @@ tcp_rx_ctrl u_tcp_rx_ctrl (
     .i_ack_number               (w_rx_ack_number),
     .i_flags                    (w_rx_flags),
     .i_window_size              (w_rx_window_size),
-    .i_hdr_valid                (w_rx_hdr_valid)
+    .i_hdr_valid                (w_rx_hdr_valid),
+
+    .o_ack_number               (w_tx_ack_number)
 );
 
 // rx buffer