[米联客-安路飞龙DR1-FPSOC] UDP通信篇连载-05 ARP层程序设计

标签：ARP arp UDP end cache begin mac 安路

软件版本：Anlogic -TD5.9.1-DR1_ES1.1

操作系统：WIN10 64bit

硬件平台：适用安路(Anlogic)FPGA

实验平台：米联客-MLK-L1-CZ06-DR1M90G开发板

板卡获取平台：https://milianke.tmall.com/

3.4 ARP层

该层具有接收ARP请求、发送ARP回复，和发送ARP请求、接收ARP回复的功能，并将接收到的对端的地址信息存入cache中。

3.4.1 ARP接收模块

该模块通过计数器接收28字节ARP信息字段。信息接收完成后，通过接收到的操作码判断接收到的数据包是ARP请求包还是ARP应答包。如果是应答包，将接收到的地址信息写入cache中；如果是请求包，判断目的IP地址与本地IP地址是否一致，若一致，将地址信息写入cache中，且发送至uiarp_rx模块，若不一致，则过滤该包。

if(OPER == ARP_REQUEST) begin//如果是ARP请求 ARP_REQUEST = 16'h0001（16'h01 ARP请求包； 16'h02 ARP应答）

if(TPA == I_ip_local_addr) begin //比较接收到的ARP包里面的IP地址是否和本地IP地址一致

O_arp_req_ip_addr <= SPA; //发送IP(远端源IP地址)

O_arp_req_mac_addr <= SHA; //发送方MAC(远端源地址MAC)

O_arp_req_valid <= 1'b1; //设置ARP请求有效(通知发送ARP发送模块发送一个ARP应答给远端主机),保存远端主机的IP地址和MAC地址到cache

O_arp_reply_done <= 1'b0;

end

else begin

O_arp_req_ip_addr <= 32'd0;

O_arp_req_mac_addr <= 48'd0;

O_arp_req_valid <= 1'b0;

O_arp_reply_done <= 1'b0;

end

3.4.2 ARP发送模块

该模块对ARP应答和ARP请求同时进行处理，首先对这两种逻辑进行仲裁，以避免发送冲突。如果既没有ARP应答也没有ARP请求，且内部ARP包发送逻辑非忙，则处理缓存的有效信号；如果只有ARP应答，没有ARP请求，且发送逻辑非忙，则请求发送ARP应答包，若发送逻辑忙，则将发送ARP应答包的请求缓存至reply_buffer_valid中，等待非忙时发出；如果只有ARP请求，没有ARP应答，且发送逻辑非忙，则请求发送ARP请求包，若发送逻辑忙，则将发送ARP请求包的请求缓存至request_buffer_valid中，等待非忙时发出；若ARP应答和ARP请求同时为高，则优先发送ARP请求，缓存ARP应答。

case({I_arp_treq_en, I_arp_rreply_en})//本状态机实现了即便是同时有ARP应答或者ARP请求，都能确保完成发送

2'b00:begin

if((!O_arp_treq) && (!O_arp_tvalid)) begin//没有arp_treq请求，并且arp_tvalid为0 代表没有要发送的ARP数据

if(request_buffer_valid) begin//如果有未发送完的ARP请求，则继续发送

OPER <= ARP_REQUEST;

TPA <= ip_request_buffer;

THA <= 48'd0;

request_buffer_valid <= 1'b0;//清除request_buffer_valid

O_arp_treq <= 1'b1;

end

else if(reply_buffer_valid) begin//如果有未发送完的ARP应答，则继续发送

OPER <= ARP_REPLY;

TPA <= ip_reply_buffer;

THA <= mac_reply_buffer;

reply_buffer_valid <= 1'b0;//清除request_buffer_valid

O_arp_treq <= 1'b1;

end

2'b01:begin//发送ARP应答

if((!O_arp_treq) && (!O_arp_tvalid)) begin

OPER <= ARP_REPLY;

TPA <= I_arp_rreply_ip_addr;

THA <= I_arp_rreply_mac_addr;

O_arp_treq <= 1'b1;

end

else begin//需要arp应答

ip_reply_buffer <= I_arp_rreply_ip_addr;//寄存目的地址IP

mac_reply_buffer <= I_arp_rreply_mac_addr;//寄存目的地址MAC

reply_buffer_valid <= 1'b1;//需要发送ARP应答

end

2'b10:begin//发送ARP请求,当ip_arp_tx发送IP包查询MAC没有查询到，执行ARP请求，请求远程主机提供MAC

if((!O_arp_treq) && (!O_arp_tvalid)) begin

OPER <= ARP_REQUEST;

TPA <= I_arp_tip_addr;

THA <= 48'd0;

O_arp_treq <= 1'b1;//ARP 发送

end

else begin//arp请求包

ip_request_buffer <= I_arp_tip_addr;

request_buffer_valid <= 1'b1;//ARP 请求有效标志

end

2'b11:begin//既有ARP请求，又有ARP应答

if((!O_arp_treq) && (!O_arp_tvalid)) begin

OPER <= ARP_REQUEST;

TPA <= I_arp_tip_addr;

THA <= 48'd0;

O_arp_treq <= 1'b1;//ARP 发送

end

else begin

ip_request_buffer <= I_arp_tip_addr;

request_buffer_valid <= 1'b1;//ARP请求有效

end

ip_reply_buffer <= I_arp_rreply_ip_addr;

mac_reply_buffer <= I_arp_rreply_mac_addr;

reply_buffer_valid <= 1'b1; //ARP应答有效

end

endcase

若O_arp_treq和uiip_arp_tx模块发送的I_arp_tbusy完成握手，则开始发送ARP包，并且通过判断ARP包的类型来确定发送的目的地址。通过计数器cnt发送28字节有效数据，再通过计数器pad_cnt在末尾补18个字节的0，即完成发送，开始等待下一次握手。

case(STATE)

WAIT_BUFFER_READY:begin

if(O_arp_treq && I_arp_tbusy) begin

O_arp_tdata <= HTYPE[15:8]; //硬件类型-以太网类型

O_arp_tvalid <= 1'b1; //ARP数据有效

cnt <= cnt + 1'b1;

if(OPER == ARP_REQUEST) begin //如果是ARP请求

O_arp_tdest_mac_addr <= 48'hff_ff_ff_ff_ff_ff; //ARP目的地址为广播地址

O_arp_ttype <= 1'b1; //通知ip_arp_tx ARP类型为ARP请求

end

else begin

O_arp_tdest_mac_addr <= THA;

O_arp_ttype <= 1'b0; //通知ip_arp_tx ARP类型为ARP应答

end

O_arp_treq <= 1'b0;

STATE <= SEND_ARP_PACKET;

end

else

STATE <= WAIT_BUFFER_READY;

end

SEND_ARP_PACKET:begin

case(cnt)

1: begin O_arp_tdata <= HTYPE[7:0]; cnt <= cnt + 1'b1;end

2: begin O_arp_tdata <= PTYPE[15:8]; cnt <= cnt + 1'b1;end

3: begin O_arp_tdata <= PTYPE[7:0]; cnt <= cnt + 1'b1;end

4: begin O_arp_tdata <= HLEN; cnt <= cnt + 1'b1;end

5: begin O_arp_tdata <= PLEN; cnt <= cnt + 1'b1;end

6: begin O_arp_tdata <= OPER[15:8]; cnt <= cnt + 1'b1;end

7: begin O_arp_tdata <= OPER[7:0]; cnt <= cnt + 1'b1;end

8: begin O_arp_tdata <= I_mac_local_addr[47:40]; cnt <= cnt + 1'b1;end

9: begin O_arp_tdata <= I_mac_local_addr[39:32]; cnt <= cnt + 1'b1;end

10: begin O_arp_tdata <= I_mac_local_addr[31:24]; cnt <= cnt + 1'b1;end

11: begin O_arp_tdata <= I_mac_local_addr[23:16]; cnt <= cnt + 1'b1;end

12: begin O_arp_tdata <= I_mac_local_addr[15:8]; cnt <= cnt + 1'b1;end

13: begin O_arp_tdata <= I_mac_local_addr[7:0]; cnt <= cnt + 1'b1;end

14: begin O_arp_tdata <= I_ip_local_addr[31:24]; cnt <= cnt + 1'b1;end

15: begin O_arp_tdata <= I_ip_local_addr[23:16]; cnt <= cnt + 1'b1;end

16: begin O_arp_tdata <= I_ip_local_addr[15:8]; cnt <= cnt + 1'b1;end

17: begin O_arp_tdata <= I_ip_local_addr[7:0]; cnt <= cnt + 1'b1;end

18: begin O_arp_tdata <= THA[47:40]; cnt <= cnt + 1'b1;end

19: begin O_arp_tdata <= THA[39:32]; cnt <= cnt + 1'b1;end

20: begin O_arp_tdata <= THA[31:24]; cnt <= cnt + 1'b1;end

21: begin O_arp_tdata <= THA[23:16]; cnt <= cnt + 1'b1;end

22: begin O_arp_tdata <= THA[15:8]; cnt <= cnt + 1'b1;end

23: begin O_arp_tdata <= THA[7:0]; cnt <= cnt + 1'b1;end

24: begin O_arp_tdata <= TPA[31:24]; cnt <= cnt + 1'b1;end

25: begin O_arp_tdata <= TPA[23:16]; cnt <= cnt + 1'b1;end

26: begin O_arp_tdata <= TPA[15:8]; cnt <= cnt + 1'b1;end

27: begin O_arp_tdata <= TPA[7:0]; cnt <= cnt + 1'b1;end

28: begin

O_arp_tdata <= 8'd0;

if(pad_cnt == 5'd17) begin //通过在末尾添加0以确保数据长度为46

cnt <= cnt + 1'b1;

pad_cnt <= 5'd0;

end

else begin

cnt <= cnt;

pad_cnt <= pad_cnt + 1'b1;

end

29: begin

O_arp_tdata <= 8'd0;

O_arp_tvalid <= 1'b0;

O_arp_tdest_mac_addr <= 48'd0;

O_arp_ttype <= 1'b0;

cnt <= 5'd0;

STATE <= WAIT_BUFFER_READY;

end

default:begin

O_arp_tdata <= 8'd0;

O_arp_tvalid <= 1'b0;

cnt <= 5'd0;

STATE <= WAIT_BUFFER_READY;

end

endcase

end

endcase

end

3.4.3 CACHE模块

mac_cache模块相当于一个RAM，通过IP作为地址，写入或读出MAC地址。写入mac_cache模块的地址信息远程主机发送的ARP应答包或ARP请求包中的地址，在IP层发送UDP数据报文时，需要在mac_cache中读出和IP地址对应的MAC地址。

`timescale 1ns/1ps

module mac_cache

(

input wire I_wclk,

input wire I_reset,

input wire I_wen,

input wire [31:0] I_wip_addr,

input wire [47:0] I_wmac_addr,

input wire I_rclk,

input wire I_ren,

input wire [31:0] I_rip_addr,

output reg [47:0] O_rmac_addr,

output reg O_rmac_done

);

reg mac_cache_flag [0:3];

reg [31:0] ip_address_cache [0:3];

reg [47:0] mac_address_cache [0:3];

reg [1:0] index;

always@(posedge I_wclk or posedge I_reset) begin

if(I_reset) begin

mac_cache_flag[0] <= 1'b0;

ip_address_cache[0] <= 32'd0;

mac_address_cache[0] <= 48'd0;

mac_cache_flag[1] <= 1'b0;

ip_address_cache[1] <= 32'd0;

mac_address_cache[1] <= 48'd0;

mac_cache_flag[2] <= 1'b0;

ip_address_cache[2] <= 32'd0;

mac_address_cache[2] <= 48'd0;

mac_cache_flag[3] <= 1'b0;

ip_address_cache[3] <= 32'd0;

mac_address_cache[3] <= 48'd0;

index <= 2'd0;

end

else begin

if(I_wen) begin

if(mac_cache_flag[0] && ip_address_cache[0] == I_wip_addr)

mac_address_cache[0] <= I_wmac_addr;

else if(mac_cache_flag[1] && ip_address_cache[1] == I_wip_addr)

mac_address_cache[1] <= I_wmac_addr;

else if(mac_cache_flag[2] && ip_address_cache[2] == I_wip_addr)

mac_address_cache[2] <= I_wmac_addr;

else if(mac_cache_flag[3] && ip_address_cache[3] == I_wip_addr)

mac_address_cache[3] <= I_wmac_addr;

else begin

mac_cache_flag[index] <= 1'b1;

ip_address_cache[index] <= I_wip_addr;

mac_address_cache[index] <= I_wmac_addr;

index <= index + 1'b1;

end

else begin

mac_cache_flag[0] <= mac_cache_flag[0];

ip_address_cache[0] <= ip_address_cache[0];

mac_address_cache[0] <= mac_address_cache[0];

mac_cache_flag[1] <= mac_cache_flag[1];

ip_address_cache[1] <= ip_address_cache[1];

mac_address_cache[1] <= mac_address_cache[1];

mac_cache_flag[2] <= mac_cache_flag[2];

ip_address_cache[2] <= ip_address_cache[2];

mac_address_cache[2] <= mac_address_cache[2];

mac_cache_flag[3] <= mac_cache_flag[3];

ip_address_cache[3] <= ip_address_cache[3];

mac_address_cache[3] <= mac_address_cache[3];

end

always@(posedge I_rclk or posedge I_reset) begin

if(I_reset) begin

O_rmac_addr <= 48'd0;

O_rmac_done <= 1'b0;

end

else begin

if(I_ren) begin

O_rmac_done <= 1'b1;

if(mac_cache_flag[0] && I_rip_addr == ip_address_cache[0])

O_rmac_addr <= mac_address_cache[0];

else if(mac_cache_flag[1] && I_rip_addr == ip_address_cache[1])

O_rmac_addr <= mac_address_cache[1];

else if(mac_cache_flag[2] && I_rip_addr == ip_address_cache[2])

O_rmac_addr <= mac_address_cache[2];

else if(mac_cache_flag[3] && I_rip_addr == ip_address_cache[3])

O_rmac_addr <= mac_address_cache[3];

else

O_rmac_addr <= 48'd0;

end

else begin

O_rmac_addr <= O_rmac_addr;

O_rmac_done <= 1'b0;

end

endmodule

标签：ARP,arp,UDP,end,cache,begin,mac,安路
From： https://www.cnblogs.com/milianke/p/18351343

[米联客-安路飞龙DR1-FPSOC] UDP通信篇连载-05 ARP层程序设计

3.4 ARP层

3.4.1 ARP接收模块

3.4.2 ARP发送模块

3.4.3 CACHE模块

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