基于PLC1850平台的ARP包请求与响应

太过爱你忘了你带给我的痛 2021-12-17 09:51 221阅读 0赞

**一、以太网ARP报文格式**

![1341836-20190326171206585-1825114634.png][]

①、以太网目的地址：占6个字节（接收方的MAC地址，不清楚时发广播地址：FF-FF-FF-FF-FF-FF）

②、以太网源地址：占6个字节（发送方的MAC地址）

③、帧类型：占2个字节（IPv4: 0x0800，ARP:0x0806，PPPoE:0x8864，802.1Q tag: 0x8100，IPV6: 0x86，DDMPLS Label:0x8847）

④、硬件类型：占2个字节（以太网的值为1即：0x0001）

⑤、协议类型：占2个字节（IPv4: 0x0800，ARP:0x0806，PPPoE:0x8864，802.1Q tag: 0x8100，IPV6: 0x86，DDMPLS Label:0x8847）

⑥、硬件地址长度：占1个字节（0x06）

⑦、协议地址长度：占1个字节（0x04）

⑧、操作类型：占2个字节（ARP请求为0x0001，ARP响应为0x0002，RARP请求为0x0003，RARP响应为0x0004）

⑨、发送方硬件地址：占6个字节（发送方的MAC地址）

⑩、发送方IP地址：占4个字节（发送方的IPv4地址）、目标硬件地址：占6个字节（接收方的MAC地址）、目标IP地址：占4个字节（接收方的IPv4地址）

**二、实现ARP请求与响应程序**

主程序：

1 #include "LPC18xx.h"
     2 #include "led.h"
     3 
     4 extern void taskEth (void);
     5 
     6 int main(void)
     7 {
     8     SystemInit();
     9 
    10     ledInit();
    11     SysTick_Config(GetCoreClock() / 1000);
    12 
    13     taskEth();
    14 
    15     while (1);  
    16 }
    17 
    18 void SysTick_Handler(void)
    19 {
    20     static int counter = 0;
    21 
    22     counter++;
    23     if (counter >= 100)
    24     {
    25         counter = 0;
    26         //ledRolling();
    27     }
    28 }

taskEth()函数程序：

1 #include <stdlib.h>
     2 #include <lpc18xx.h>
     3 #include "lpc18xx_emac.h"
     4 #include "lpc18xx_debug.h"
     5 
     6 extern uint32_t ipatol(char * p_input);
     7 extern void ipInit(uint8_t * mac, uint32_t ip);
     8 extern uint32_t ipRcvMacFrame(uint8_t * block, uint32_t frameLen);
     9 extern void arpSndRsp1(uint32_t dstIp,uint32_t resIp, uint8_t *f_mac,uint8_t *mac);
    10 
    11 uint8_t gFlag;
    12 
    13 uint8_t g_emacBuffer[2048];
    14 
    15 uint8_t g_ethMac[6];
    16 
    17 uint8_t F_ethMac[6];
    18 
    19 // EMAC接口接收到的数据，通知应用层回调函数
    20 void ethReadReadyCb()
    21 {
    22     gFlag = 1;
    23 }
    24 
    25 void taskEth (void)
    26 {    
    27     uint32_t len;
    28 
    29    // 板子的MAK地址
    30    g_ethMac[0] = 0x11;
    31    g_ethMac[1] = 0x1F;
    32    g_ethMac[2] = 0xE0;
    33    g_ethMac[3] = 0x12;
    34    g_ethMac[4] = 0x1E;
    35    g_ethMac[5] = 0x0F;
    36     
    37     //广播地址
    38     F_ethMac[0]=0xff;
    39     F_ethMac[1]=0xff;
    40     F_ethMac[2]=0xff;
    41     F_ethMac[3]=0xff;
    42     F_ethMac[4]=0xff;
    43     F_ethMac[5]=0xff;
    44     //串口初始化
    45     debugComInit();
    46     uartPrint("uart init\r\n");
    47 
    48     //以太网初始化
    49   while (ethInit(ethReadReadyCb, g_ethMac) == 0);
    50 
    51     uartPrint("eth init complete\r\n");
    52     // 为以太网接口指定MAC地址和IP地址
    53     ipInit(g_ethMac, 0xBE01A8C0);   // 192.168.1.190
    54     //发送ARP请求函数
    55     arpSndRsp1(0x0201A8C0,0xBE01A8C0,F_ethMac,g_ethMac);
    56   while (1)
    57   {
    58             if (!gFlag)
    59             {
    60                 continue;
    61             }
    62     　　　　　//读取是否接收到报文
    63             len = ethRead(g_emacBuffer, 2048); 
    64         
    65             if(len)
    66             {
    67                 ipRcvMacFrame((uint8_t *)g_emacBuffer, len);  //接收报文  
    68             }        
    69             gFlag=0;        
    70     }
    71 }

arpSndRsp1()、ethRead()和ipRcvMacFrame()函数程序如下：

1 #include <stdint.h>
      2 #include <string.h>
      3 #include <stdlib.h>
      4 #include "lpc18xx_emac.h"
      5 #include "lpc18xx_debug.h"
      6 //#include "shell.h"
      7 
      8 #define MAC_TYPE_IP   0x0800  //ip类型
      9 #define MAC_TYPE_ARP  0x0806  //mac类型
     10 
     11 #define ARP_REQ 0x0001      //ARP请求
     12 #define ARP_RSP 0x0002        //ARP响应
     13 
     14 #define ICMP_ECHO_REQUEST    8                   // message is an echo request
     15 #define ICMP_ECHO_REPLY      0                   // message is an echo reply
     16 
     17 #define PROT_ICMP            1                   // Internet Control Message Protocol
     18 #define PROT_TCP             6                   // Transmission Control Protocol
     19 #define PROT_UDP             17                  // User Datagram Protocol
     20 
     21 #define DONT_FRAGMENT       0x4000 //fragment
     22 #define MORE_FRAGMENT       0x2000
     23 #define FRAGMENT_OFFSET     0x1FFF
     24 
     25 uint8_t PLC_ethMacAddr[6];
     26 uint8_t F_ethMacAddr[6];
     27 
     28 uint8_t g_ethMacAddr[6];
     29 uint32_t g_ethIpAddr;
     30 
     31 uint32_t g_ipSndBuffer[64];
     32 
     33 uint16_t g_ipIdentifier = 0;
     34 
     35 //将字从主机序转为网络序
     36 uint16_t htons(uint16_t word)
     37 {
     38     return ((word >> 8) & 0x00FF) | ((word << 8) & 0xFF00);
     39 }
     40 
     41 //将字从网络序转为主机序
     42 uint16_t ntohs(uint16_t word)
     43 {
     44     return ((word >> 8) & 0x00FF) | ((word << 8) & 0xFF00);
     45 }
     46 
     47 
     48 uint16_t calcChecksum(uint16_t * buffer, uint32_t size)   
     49 {   
     50     uint32_t cksum;   
     51     
     52     cksum = 0;   
     53 
     54     while (size > 1)   
     55     {   
     56         cksum += *buffer++;   
     57         size -= sizeof(uint16_t);         
     58     }   
     59 
     60     if (size)   
     61     {   
     62         cksum += *(uint8_t*)buffer;         
     63     }   
     64 
     65     cksum = (cksum >> 16) + (cksum & 0xffff);   
     66     cksum += (cksum >>16);     
     67     
     68     return (uint16_t)(~cksum);     
     69 }
     70 //发送ARP请求
     71 void arpSndRsp1(uint32_t dstIp,uint32_t resIp, uint8_t *f_mac,uint8_t *mac)
     72 {
     73     uint8_t * block;
     74     //uint32_t blockLen;
     75 
     76     block = (uint8_t *)g_ipSndBuffer;//64
     77 
     78     memcpy(block, mac, 6);//以太网目的广播地址
     79 
     80     memcpy(block + 6, mac, 6);//以太网的源地址，也就是板子的MAC地址 81 
     82     // arp type
     83     *(uint16_t *)&block[12] = htons(MAC_TYPE_ARP);//mac类型
     84 
     85     // --------- ARP 层
     86     
     87     // Hardway type : Ethernet
     88     block[14] = 0x00;
     89     block[15] = 0x01;
     90 
     91     // ip type
     92     *(uint16_t *)&block[16] = htons(MAC_TYPE_IP);//IP类型
     93 
     94     // Hardway size
     95     block[18] = 0x06;//硬件地址长度 96 
     97     // Protocal size
     98     block[19] = 0x04;//协议地址长度
     99 
    100     // arp reply
    101     *(uint16_t *)&block[20] = htons(ARP_REQ);//ARPARP请求
    102 
    103     // Sender MAC address
    104     memcpy(block + 22, mac, 6);//发送者的Mac地址
    105         
    106     memcpy(PLC_ethMacAddr, mac, 6);//复制发送者的mac地址107         
    108     // Sender IP address
    109     *(uint32_t *)&block[28] = resIp;//发送者IP地址110 
    111     // Target MAC address
    112     memcpy(block + 32, f_mac, 6);
    113         
    114     memcpy(F_ethMacAddr, f_mac, 6);//复制目的广播地址115 
    116     // Target IP address : 192.168.0.67
    117     block[38] = (uint8_t)dstIp;
    118     block[39] = (uint8_t)(dstIp >> 8);
    119     block[40] = (uint8_t)(dstIp >> 16);
    120     block[41] = (uint8_t)(dstIp >> 24);
    121 
    122     // 18填充
    123     memset(block + 42, 0, 18);
    124 
    125     ethWrite((uint8_t *)block, 60);
    126         uartPrint("sended ARP\r\n");
    127 }
    128 //发送ARP响应
    129 void arpSndRsp(uint32_t dstIp, uint8_t * mac)
    130 {
    131     uint8_t * block;
    132     //uint32_t blockLen;
    133 
    134     block = (uint8_t *)g_ipSndBuffer;//64
    135 
    136     memcpy(block, mac, 6);
    137 
    138     memcpy(block + 6, g_ethMacAddr, 6);
    139 
    140     // arp type
    141     *(uint16_t *)&block[12] = htons(MAC_TYPE_ARP);
    142 
    143     // --------- ARP 层
    144     
    145     // Hardway type : Ethernet
    146     block[14] = 0x00;
    147     block[15] = 0x01;
    148 
    149     // ip type
    150     *(uint16_t *)&block[16] = htons(MAC_TYPE_IP);
    151 
    152     // Hardway size
    153     block[18] = 0x06;
    154 
    155     // Protocal size
    156     block[19] = 0x04;
    157 
    158     // arp reply
    159     *(uint16_t *)&block[20] = htons(ARP_RSP);
    160 
    161     // Sender MAC address
    162     memcpy(block + 22, g_ethMacAddr, 6);
    163 
    164     // Sender IP address
    165     *(uint32_t *)&block[28] = g_ethIpAddr;
    166 
    167     // Target MAC address
    168     memcpy(block + 32, mac, 6);
    169 
    170     // Target IP address : 192.168.0.67
    171     block[38] = (uint8_t)dstIp;
    172     block[39] = (uint8_t)(dstIp >> 8);
    173     block[40] = (uint8_t)(dstIp >> 16);
    174     block[41] = (uint8_t)(dstIp >> 24);
    175 
    176     // 18个填充字节
    177     memset(block + 42, 0, 18);
    178 
    179     ethWrite((uint8_t *)block, 60);
    181 }
    182 //接收ARP数据包
    183 void arpRcv(uint8_t * block, uint32_t frameLen)
    184 {
    185       uint64_t dstMac;
    186     uint32_t srcIp, dstIp,i;
    187     uint16_t msgType;
    188     
    189     //报文类型，占2个字节
    190     msgType = ntohs(*(uint16_t *)(block+6));   
    191     //源IP
    192     srcIp = (uint32_t)*(uint16_t *)(block + 14);
    193     srcIp|= ((uint32_t)*(uint16_t *)(block + 16)) << 16;
    194         
    195     dstMac=(uint64_t)*(uint16_t *)(block + 18);
    196     dstMac|=((uint64_t)*(uint16_t *)(block + 20)) << 16;
    197     dstMac|=((uint64_t)*(uint16_t *)(block + 22)) << 16;
    198     
    199     //目的IP
    200     dstIp = (uint32_t)*(uint16_t *)(block + 24);
    201     dstIp|= ((uint32_t)*(uint16_t *)(block + 26)) << 16;
    202 
    203     if (dstIp != g_ethIpAddr)
    204     {
    205         return;
    206     }
    207     if (msgType == ARP_RSP)
    208     {
    209             uartPrint("ARP Information:\r\n");
    210             //硬件类型
    211             uartPrint("ar_pro:%x%x\r\n",*(block+2),*(block+3));            
    212             //硬件地址长度
    213             uartPrint("ar_hln:%d\r\n",*(block+4));
    214             //协议地址长度
    215             uartPrint("ar_pln:%d\r\n",*(block+5));
    216             //操作类型
    217             uartPrint(" AR_op:%x\r\n",msgType);
    218             //电脑的MAC地址
    219             uartPrint("ComputerMac:%x.%x.%x.%x.%x.%x\r\n",*(block+8),*(block+9),*(block+10),*(block+11),*(block+12),*(block+13));
    220             //电脑的IP地址
    221             uartPrint("ComputerIp:%d.%d.%d.%d\r\n",*(block+14),*(block+15),*(block+16),*(block+17));
    222             //板子的MAC地址
    223             uartPrint("PLC1850Mac:%x.%x.%x.%x.%x.%x\r\n",*(block+18),*(block+19),*(block+20),*(block+21),*(block+22),*(block+23));
    224             //板子的IP地址
    225             uartPrint("PLC1850Ip:%d.%d.%d.%d",*(block+24),*(block+25),*(block+26),*(block+27));
    226 //      arpSndRsp(srcIp, block + 8);
    227     }
    228 }
    229 
    230 //不管成功与否，都由IP层来释放数据包
    231 void ipSnd(uint32_t dstIp, uint8_t * block, uint32_t len, uint8_t protoType, uint8_t * mac)
    232 {
    233     block-= 20;
    234     len+= 20;
    235     
    236     // ------------ IP 层
    237     
    238     block[0] = 0x45;  // IP V4.  length 20(5*4)
    239     
    240     block[1] = 0x00;  // service
    241     
    242     *(uint16_t *)&block[2] = htons(len);
    243     
    244     *(uint16_t *)&block[4] = htons((uint16_t)g_ipIdentifier++); // identification
    245     
    246     *(uint16_t *)&block[6] = 0x0040; // flag and fragment
    247 
    248     block[8] = 128;  // TTL
    249 
    250     block[9] = protoType;
    251     
    252     *(uint16_t *)&block[10] = 0; // 校验和先填上0
    253     
    254     *(uint16_t *)&block[12] = (uint16_t)g_ethIpAddr;
    255     *(uint16_t *)&block[14] = (uint16_t)(g_ethIpAddr >> 16);
    256 
    257     *(uint16_t *)&block[16] = (uint16_t)dstIp;
    258     *(uint16_t *)&block[18] = (uint16_t)(dstIp >> 16);
    259     
    260     *(uint16_t *)&block[10] = calcChecksum((uint16_t *)block, 20);
    261 
    262     // ------------ MAC 层
    263 
    264     block-= 14;
    265     len+= 14;
    266     
    267     memcpy(block, mac , 6);
    268     
    269     memcpy(block + 6, g_ethMacAddr, 6);
    270 
    271     *(uint16_t *)&block[12] = htons(MAC_TYPE_IP);
    272 
    273     if (len < 60)
    274     {
    275         // MAC帧太短，补到最短长度
    276         memset(block + len, 0, 60 - len);
    277         len = 60;
    278     }
    279 
    280     ethWrite((uint8_t *)block, len);
    281 }
    282 
    283 // ICMP收到请求，需要回响应
    284 void icmpRcvRequest(uint32_t srcIp, uint8_t * icmp, uint32_t len, uint8_t * mac)
    285 {
    286     uint8_t * block;
    287 
    288     block = (uint8_t *)g_ipSndBuffer;
    289 
    290     //留出14(MAC)+20(IP)个字节
    291     block+=(14+20);
    292     
    293     // ----------- ICMP层
    294     memcpy(block, icmp, len);
    295     
    296     block[0] = ICMP_ECHO_REPLY;
    297     block[1] = 0;   // code
    298     
    299     *(uint16_t *)&block[2] = 0;  //校验和先填上0
    300     
    301     *(uint16_t *)&block[2] = calcChecksum((uint16_t *)block, len);
    302 
    303     ipSnd(srcIp, (void *)block, len, PROT_ICMP, mac);
    304 }
    305 
    306 //接收到IP包的处理
    307 void ipRcv(uint8_t * frame, uint32_t frameLen, uint8_t * mac)
    308 {
    309     uint16_t ipLength, flag;
    310     uint32_t srcIp, dstIp;
    311 
    312     if (frameLen < 20)
    313     {
    314         return;
    315     }
    316 
    317     if (calcChecksum((uint16_t *)frame, 20))
    318     {
    319         //校验和不正确
    320         return;
    321     }
    322 
    323     if (frame[0] != 0x45)
    324     {
    325         // IP VERSION应为4，长度应为20（5个bit 32）字节
    326         return;
    327     }
    328 
    329     // ignore Type Of Service
    330     
    331     ipLength = ntohs(*(uint16_t *)&frame[2]);
    332 
    333     // ignore identification
    334 
    335     flag = ntohs(*(uint16_t *)&frame[6]);
    336 
    337     if (!(flag & DONT_FRAGMENT))
    338     {
    339         // IP可以被分包，但只处理不分包情况
    340         
    341         if (flag & MORE_FRAGMENT)
    342         {
    343             // 非最后一包，丢弃
    344             return;
    345         }
    346         
    347         // 是最后一包
    348         
    349         if (flag & FRAGMENT_OFFSET)
    350         {
    351             // 是最后一包，且偏移量不为0，也丢弃
    352             return;
    353         }
    354         
    355         //最后一包，且偏移量为0，是整包，处理
    356     }
    357     
    358     if (frameLen < ipLength)
    359     {
    360         return;
    361     }
    362     
    363     // ignore fragment offset
    364 
    365     //ttl = (uint32_t)frame[8];
    366 
    367     //srcIp = (frame[12] | (frame[13]<< 8) | (frame[14] << 16) | (frame[15] << 24));
    368     //dstIp = (frame[16] | (frame[17]<< 8) | (frame[18] << 16) | (frame[19] << 24));
    369 
    370     srcIp = *(uint16_t *)(frame + 12) | ((uint32_t)*(uint16_t *)(frame + 14) << 16);
    371     dstIp = *(uint16_t *)(frame + 16) | ((uint32_t)*(uint16_t *)(frame + 18) << 16);
    372 
    373     if ((dstIp != g_ethIpAddr) && (dstIp != 0x0100007F) && (dstIp != 0xffffffff))
    374     {
    375         return;
    376     }
    377 
    378     if (frame[9] != PROT_ICMP)
    379     {
    380         // 非ICMP包，暂不处理
    381         return;
    382     }
    383 
    384     if (frame[20] == ICMP_ECHO_REQUEST)
    385     {
    386         icmpRcvRequest(srcIp, frame + 20, ipLength - 20, mac);
    387     }
    388 }
    389 
    390 // IP层接收MAC层数据帧的函数
    391 uint32_t ipRcvMacFrame(uint8_t * block, uint32_t frameLen)
    392 {
    393     uint32_t i;
    394     //判断是否收到ARP响应
    397         if ((memcmp(block, PLC_ethMacAddr, 6) == 0))
    398     {
    399         uartPrint("received\r\n");
    400         //发给本机的
    401         switch (ntohs(*(uint16_t *)(block+12)))
    402         {
    403         case MAC_TYPE_ARP://ARP报文
    405             arpRcv(block + 14, frameLen -14);//去掉针头，从ARP包开始
    406             break;
    407         case MAC_TYPE_IP://IP报文
    408             ipRcv(block + 14, frameLen - 14, block+6);
    409             break;
    410         default:
    411             break;
    412         }
    413     }
    414         else //若没有收到，继续发送ARP请求
    415         {
    416             arpSndRsp1(0x0201A8C0,0xBE01A8C0,F_ethMacAddr,PLC_ethMacAddr);
    417         }
    418     return 1;
    419 }
    420 
    421 void ipInit(uint8_t * mac, uint32_t ip)
    422 {
    423     memcpy(g_ethMacAddr, mac, 6);
    424     g_ethIpAddr = ip;
    425 }

以上代码实现LPC1850对电脑以太网口发起ARP请求以及抓取响应的ARP包。

转载于:https://www.cnblogs.com/chenfeifen/p/10601391.html

[1341836-20190326171206585-1825114634.png]: /images/20211217/ea7171b2fed34f6593dcb8c7ca26415f.png