通信协议之ICMP协议的FPGA实现
整体的实现框图如下所示
arp_rx.v
module arp_rx
#(
//开发板MAC地址 00-11-22-33-44-55
parameter BOARD_MAC = 48'h00_11_22_33_44_55,
//开发板IP地址 192.168.1.10
parameter BOARD_IP = {
8'd192,8'd168,8'd1,8'd10}
)
(
input clk , //时钟信号
input rst_n , //复位信号，低电平有效
input gmii_rx_dv , //GMII输入数据有效信号
input [7:0] gmii_rxd , //GMII输入数据
output reg arp_rx_done, //ARP接收完成信号
output reg arp_rx_type, //ARP接收类型 0:请求 1:应答
output reg [47:0] src_mac , //接收到的源MAC地址
output reg [31:0] src_ip //接收到的源IP地址
);
//parameter define
localparam st_idle = 5'b0_0001; //初始状态，等待接收前导码
localparam st_preamble = 5'b0_0010; //接收前导码状态
localparam st_eth_head = 5'b0_0100; //接收以太网帧头
localparam st_arp_data = 5'b0_1000; //接收ARP数据
localparam st_rx_end = 5'b1_0000; //接收结束
localparam ETH_TPYE = 16'h0806; //以太网帧类型 ARP
//reg define
reg [4:0] cur_state ;
reg [4:0] next_state;
reg skip_en ; //控制状态跳转使能信号
reg error_en ; //解析错误使能信号
reg [4:0] cnt ; //解析数据计数器
reg [47:0] des_mac_t ; //接收到的目的MAC地址
reg [31:0] des_ip_t ; //接收到的目的IP地址
reg [47:0] src_mac_t ; //接收到的源MAC地址
reg [31:0] src_ip_t ; //接收到的源IP地址
reg [15:0] eth_type ; //以太网类型
reg [15:0] op_data ; //操作码
//*****************************************************
//** main code
//*****************************************************
//(三段式状态机)同步时序描述状态转移
always @(posedge clk or negedge rst_n) begin
if(!rst_n)
cur_state <= st_idle;
else
cur_state <= next_state;
end
//组合逻辑判断状态转移条件
always @(*) begin
next_state = st_idle;
case(cur_state)
st_idle : begin //等待接收前导码
if(skip_en)
next_state = st_preamble;
else
next_state = st_idle;
end
st_preamble : begin //接收前导码
if(skip_en)
next_state = st_eth_head;
else if(error_en)
next_state = st_rx_end;
else
next_state = st_preamble;
end
st_eth_head : begin //接收以太网帧头
if(skip_en)
next_state = st_arp_data;
else if(error_en)
next_state = st_rx_end;
else
next_state = st_eth_head;
end
st_arp_data : begin //接收ARP数据
if(skip_en)
next_state = st_rx_end;
else if(error_en)
next_state = st_rx_end;
else
next_state = st_arp_data;
end
st_rx_end : begin //接收结束
if(skip_en)
next_state = st_idle;
else
next_state = st_rx_end;
end
default : next_state = st_idle;
endcase
end
//时序电路描述状态输出,解析以太网数据
always @(posedge clk or negedge rst_n) begin
if(!rst_n) begin
skip_en <= 1'b0;
error_en <= 1'b0;
cnt <= 5'd0;
des_mac_t <= 48'd0;
des_ip_t <= 32'd0;
src_mac_t <= 48'd0;
src_ip_t <= 32'd0;
eth_type <= 16'd0;
op_data <= 16'd0;
arp_rx_done <= 1'b0;
arp_rx_type <= 1'b0;
src_mac <= 48'd0;
src_ip <= 32'd0;
end
else begin
skip_en <= 1'b0;
error_en <= 1'b0;
arp_rx_done <= 1'b0;
case(next_state)
st_idle : begin //检测到第一个8'h55
if((gmii_rx_dv == 1'b1) && (gmii_rxd == 8'h55))
skip_en <= 1'b1;
else;
end
st_preamble : begin
if(gmii_rx_dv) begin //解析前导码
cnt <= cnt + 5'd1;
if((cnt < 5'd6) && (gmii_rxd != 8'h55)) //7个8'h55
error_en <= 1'b1;
else if(cnt==5'd6) begin
cnt <= 5'd0;
if(gmii_rxd==8'hd5) //1个8'hd5
skip_en <= 1'b1;
else
error_en <= 1'b1;
end
else;
end
else;
end
st_eth_head : begin
if(gmii_rx_dv) begin
cnt <= cnt + 5'b1;
if(cnt < 5'd6)
des_mac_t <= {
des_mac_t[39:0],gmii_rxd};
else if(cnt == 5'd6) begin
//判断MAC地址是否为开发板MAC地址或者公共地址
if((des_mac_t != BOARD_MAC)
&& (des_mac_t != 48'hff_ff_ff_ff_ff_ff))
error_en <= 1'b1;
end
else if(cnt == 5'd12)
eth_type[15:8] <= gmii_rxd; //以太网协议类型
else if(cnt == 5'd13) begin
eth_type[7:0] <= gmii_rxd;
cnt <= 5'd0;
if(eth_type[15:8] == ETH_TPYE[15:8] //判断是否为ARP协议
&& gmii_rxd == ETH_TPYE[7:0])
skip_en <= 1'b1;
else
error_en <= 1'b1;
end
else;
end
else;
end
st_arp_data : begin
if(gmii_rx_dv) begin
cnt <= cnt + 5'd1;
if(cnt == 5'd6)
op_data[15:8] <= gmii_rxd; //操作码
else if(cnt == 5'd7)
op_data[7:0] <= gmii_rxd;
else if(cnt >= 5'd8 && cnt < 5'd14) //源MAC地址
src_mac_t <= {
src_mac_t[39:0],gmii_rxd};
else if(cnt >= 5'd14 && cnt < 5'd18) //源IP地址
src_ip_t<= {
src_ip_t[23:0],gmii_rxd};
else if(cnt >= 5'd24 && cnt < 5'd28) //目标IP地址
des_ip_t <= {
des_ip_t[23:0],gmii_rxd};
else if(cnt == 5'd28) begin
cnt <= 5'd0;
if(des_ip_t == BOARD_IP) begin //判断目的IP地址和操作码
if((op_data == 16'd1) || (op_data == 16'd2)) begin
skip_en <= 1'b1;
arp_rx_done <= 1'b1;
src_mac <= src_mac_t;
src_ip <= src_ip_t;
src_mac_t <= 48'd0;
src_ip_t <= 32'd0;
des_mac_t <= 48'd0;
des_ip_t <= 32'd0;
if(op_data == 16'd1)
arp_rx_type <= 1'b0; //ARP请求
else
arp_rx_type <= 1'b1; //ARP应答
end
else
error_en <= 1'b1;
end
else
error_en <= 1'b1;
end
else;
end
else;
end
st_rx_end : begin
cnt <= 5'd0;
//单包数据接收完成
if(gmii_rx_dv == 1'b0 && skip_en == 1'b0)
skip_en <= 1'b1;
else;
end
default : ;
endcase
end
end
endmodule
arp_tx.v
module arp_tx(
input clk , //时钟信号
input rst_n , //复位信号，低电平有效
input arp_tx_en , //ARP发送使能信号
input arp_tx_type, //ARP发送类型 0:请求 1:应答
input [47:0] des_mac , //发送的目标MAC地址
input [31:0] des_ip , //发送的目标IP地址
input [31:0] crc_data , //CRC校验数据
input [7:0] crc_next , //CRC下次校验完成数据
output reg tx_done , //以太网发送完成信号
output reg gmii_tx_en , //GMII输出数据有效信号
output reg [7:0] gmii_txd , //GMII输出数据
output reg crc_en , //CRC开始校验使能
output reg crc_clr //CRC数据复位信号
);
//parameter define
//开发板MAC地址 00-11-22-33-44-55
parameter BOARD_MAC = 48'h00_11_22_33_44_55;
//开发板IP地址 192.168.1.10
parameter BOARD_IP = {
8'd192,8'd168,8'd1,8'd10};
//目的MAC地址 ff_ff_ff_ff_ff_ff
parameter DES_MAC = 48'hff_ff_ff_ff_ff_ff;
//目的IP地址 192.168.1.102
parameter DES_IP = {
8'd192,8'd168,8'd1,8'd102};
localparam st_idle = 5'b0_0001; //初始状态，等待开始发送信号
localparam st_preamble = 5'b0_0010; //发送前导码+帧起始界定符
localparam st_eth_head = 5'b0_0100; //发送以太网帧头
localparam st_arp_data = 5'b0_1000; //
localparam st_crc = 5'b1_0000; //发送CRC校验值
localparam ETH_TYPE = 16'h0806 ; //以太网帧类型 ARP协议
localparam HD_TYPE = 16'h0001 ; //硬件类型 以太网
localparam PROTOCOL_TYPE= 16'h0800 ; //上层协议为IP协议
//以太网数据最小为46个字节,不足部分填充数据
localparam MIN_DATA_NUM = 16'd46 ;
//reg define
reg [4:0] cur_state ;
reg [4:0] next_state ;
reg [7:0] preamble[7:0] ; //前导码+SFD
reg [7:0] eth_head[13:0]; //以太网首部
reg [7:0] arp_data[27:0]; //ARP数据
reg tx_en_d0 ; //arp_tx_en信号延时
reg tx_en_d1 ;
reg tx_en_d2 ;
reg skip_en ; //控制状态跳转使能信号
reg [5:0] cnt ;
reg [4:0] data_cnt ; //发送数据个数计数器
reg tx_done_t ;
//wire define
wire pos_tx_en ; //arp_tx_en信号上升沿
//*****************************************************
//** main code
//*****************************************************
assign pos_tx_en = (~tx_en_d2) & tx_en_d1;
//对arp_tx_en信号延时打拍两次,用于采arp_tx_en的上升沿
always @(posedge clk or negedge rst_n) begin
if(!rst_n) begin
tx_en_d0 <= 1'b0;
tx_en_d1 <= 1'b0;
tx_en_d2 <= 1'b0;
end
else begin
tx_en_d0 <= arp_tx_en;
tx_en_d1 <= tx_en_d0;
tx_en_d2 <= tx_en_d1;
end
end
//(三段式状态机)同步时序描述状态转移
always @(posedge clk or negedge rst_n) begin
if(!rst_n)
cur_state <= st_idle;
else
cur_state <= next_state;
end
//组合逻辑判断状态转移条件
always @(*) begin
next_state = st_idle;
case(cur_state)
st_idle : begin //空闲状态
if(skip_en)
next_state = st_preamble;
else
next_state = st_idle;
end
st_preamble : begin //发送前导码+帧起始界定符
if(skip_en)
next_state = st_eth_head;
else
next_state = st_preamble;
end
st_eth_head : begin //发送以太网首部
if(skip_en)
next_state = st_arp_data;
else
next_state = st_eth_head;
end
st_arp_data : begin //发送ARP数据
if(skip_en)
next_state = st_crc;
else
next_state = st_arp_data;
end
st_crc: begin //发送CRC校验值
if(skip_en)
next_state = st_idle;
else
next_state = st_crc;
end
default : next_state = st_idle;
endcase
end
//时序电路描述状态输出，发送以太网数据
always @(posedge clk or negedge rst_n) begin
if(!rst_n) begin
skip_en <= 1'b0;
cnt <= 6'd0;
data_cnt <= 5'd0;
crc_en <= 1'b0;
gmii_tx_en <= 1'b0;
gmii_txd <= 8'd0;
tx_done_t <= 1'b0;
//初始化数组
//前导码 7个8'h55 + 1个8'hd5
preamble[0] <= 8'h55;
preamble[1] <= 8'h55;
preamble[2] <= 8'h55;
preamble[3] <= 8'h55;
preamble[4] <= 8'h55;
preamble[5] <= 8'h55;
preamble[6] <= 8'h55;
preamble[7] <= 8'hd5;
//以太网帧头
eth_head[0] <= DES_MAC[47:40]; //目的MAC地址
eth_head[1] <= DES_MAC[39:32];
eth_head[2] <= DES_MAC[31:24];
eth_head[3] <= DES_MAC[23:16];
eth_head[4] <= DES_MAC[15:8];
eth_head[5] <= DES_MAC[7:0];
eth_head[6] <= BOARD_MAC[47:40]; //源MAC地址
eth_head[7] <= BOARD_MAC[39:32];
eth_head[8] <= BOARD_MAC[31:24];
eth_head[9] <= BOARD_MAC[23:16];
eth_head[10] <= BOARD_MAC[15:8];
eth_head[11] <= BOARD_MAC[7:0];
eth_head[12] <= ETH_TYPE[15:8]; //以太网帧类型
eth_head[13] <= ETH_TYPE[7:0];
//ARP数据
arp_data[0] <= HD_TYPE[15:8]; //硬件类型
arp_data[1] <= HD_TYPE[7:0];
arp_data[2] <= PROTOCOL_TYPE[15:8]; //上层协议类型
arp_data[3] <= PROTOCOL_TYPE[7:0];
arp_data[4] <= 8'h06; //硬件地址长度,6
arp_data[5] <= 8'h04; //协议地址长度,4
arp_data[6] <= 8'h00; //OP,操作码 8'h01：ARP请求 8'h02:ARP应答
arp_data[7] <= 8'h01;
arp_data[8] <= BOARD_MAC[47:40]; //发送端(源)MAC地址
arp_data[9] <= BOARD_MAC[39:32];
arp_data[10] <= BOARD_MAC[31:24];
arp_data[11] <= BOARD_MAC[23:16];
arp_data[12] <= BOARD_MAC[15:8];
arp_data[13] <= BOARD_MAC[7:0];
arp_data[14] <= BOARD_IP[31:24]; //发送端(源)IP地址
arp_data[15] <= BOARD_IP[23:16];
arp_data[16] <= BOARD_IP[15:8];
arp_data[17] <= BOARD_IP[7:0];
arp_data[18] <= DES_MAC[47:40]; //接收端(目的)MAC地址
arp_data[19] <= DES_MAC[39:32];
arp_data[20] <= DES_MAC[31:24];
arp_data[21] <= DES_MAC[23:16];
arp_data[22] <= DES_MAC[15:8];
arp_data[23] <= DES_MAC[7:0];
arp_data[24] <= DES_IP[31:24]; //接收端(目的)IP地址
arp_data[25] <= DES_IP[23:16];
arp_data[26] <= DES_IP[15:8];
arp_data[27] <= DES_IP[7:0];
end
else begin
skip_en <= 1'b0;
crc_en <= 1'b0;
gmii_tx_en <= 1'b0;
tx_done_t <= 1'b0;
case(next_state)
st_idle : begin
if(pos_tx_en) begin
skip_en <= 1'b1;
//如果目标MAC地址和IP地址已经更新,则发送正确的地址
if((des_mac != 48'b0) || (des_ip != 32'd0)) begin
eth_head[0] <= des_mac[47:40];
eth_head[1] <= des_mac[39:32];
eth_head[2] <= des_mac[31:24];
eth_head[3] <= des_mac[23:16];
eth_head[4] <= des_mac[15:8];
eth_head[5] <= des_mac[7:0];
arp_data[18] <= des_mac[47:40];
arp_data[19] <= des_mac[39:32];
arp_data[20] <= des_mac[31:24];
arp_data[21] <= des_mac[23:16];
arp_data[22] <= des_mac[15:8];
arp_data[23] <= des_mac[7:0];
arp_data[24] <= des_ip[31:24];
arp_data[25] <= des_ip[23:16];
arp_data[26] <= des_ip[15:8];
arp_data[27] <= des_ip[7:0];
end
else;
if(arp_tx_type == 1'b0)
arp_data[7] <= 8'h01
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