arp1.lst

cf8020+cp2200(网络)的驱动实现

C51 COMPILER V7.09   ARP1                                                                  06/28/2007 09:51:20 PAGE 1   


C51 COMPILER V7.09, COMPILATION OF MODULE ARP1
OBJECT MODULE PLACED IN ARP1.obj
COMPILER INVOKED BY: F:\Keil\C51\BIN\C51.EXE tcp\ARP1.C LARGE BROWSE DEBUG OBJECTEXTEND PRINT(.\ARP1.lst) OBJECT(ARP1.ob
                    -j)

line level    source

   1          //-----------------------------------------------------------------------------
   2          // Copyright (c) 2002 Jim Brady
   3          // Do not use commercially without author's permission
   4          // Last revised August 2002
   5          // Net ARP.C
   6          //
   7          // This module handles ARP messages and ARP resolution and manages
   8          // the ARP cache. Refer to RFC 826 and RFC 1122
   9          //-----------------------------------------------------------------------------
  10          //#include "stdio.h"
  11          
  12          #include "stdlib.h"
  13          #include "net1.h"
  14          #include "eth1.h"
  15          #include "serial1.h"
  16          #include "ip1.h"
  17          #include "arp1.h"
  18          #include "utils.h"
  19          
  20          
  21          extern WAIT  wait;
  22          extern UCHAR  my_hwaddr[];
  23          extern UCHAR  broadcast_hwaddr[]; 
  24          extern ulong  my_ipaddr;
  25          extern ulong  my_subnet;
  26          extern ulong  gateway_ipaddr;
  27          extern UCHAR  debug;
  28          ARP_CACHE  arp_cache[CACHESIZE];
  29          UCHAR waiting_for_arp;
  30          
  31          
  32          void init_arp(void)
  33          {
  34   1              memset(arp_cache, 0, sizeof(arp_cache)); 
  35   1              memset(&wait, 0, sizeof(wait));
  36   1              waiting_for_arp = FALSE;
  37   1      }
  38          
  39          
  40          
  41          
  42          //------------------------------------------------------------------------
  43          //      This is called every 60 seconds to age the ARP cache
  44          // If an entry times out then it is deleted from the cache
  45          // See "TCP/IP Illustrated, Volume 1" Sect 4.3
  46          //------------------------------------------------------------------------
  47          
  48          //每隔60 s刷新一次ARP表. 超过60s未用的记录删掉.
  49          void age_arp_cache(void)
  50          {
  51   1              UCHAR i;
  52   1              
  53   1         for (i=0; i < CACHESIZE; i++)
  54   1         {  //如果ARP cahce表的某一记录的ipaddr和timer不为0,此记录的timer减一．如果减一等于0,　此记录丢弃. 
C51 COMPILER V7.09   ARP1                                                                  06/28/2007 09:51:20 PAGE 2   

  55   2            if ((arp_cache[i].ipaddr != 0) && (arp_cache[i].timer))
  56   2            {
  57   3               arp_cache[i].timer--;
  58   3                      if (arp_cache[i].timer == 0)
  59   3               {
  60   4                                      // Timed out so clear out cache entry
  61   4                                      // Do not need to zero hwaddr
  62   4                                      arp_cache[i].ipaddr = 0;
  63   4      //                              if (debug) serial_send("ARP: Aged out a cache entry\r");
  64   4                              }
  65   3                      }
  66   2         }
  67   1      }
  68          
  69          
  70          
  71          
  72          //------------------------------------------------------------------------
  73          // This allocates memory for the entire outgoing message,
  74          // including eth and ip headers, then builds an outgoing
  75          // ARP response message
  76          // See "TCP/IP Illustrated, Volume 1" Sect 4.4
  77          //------------------------------------------------------------------------
  78          //arp_send(arp->source_hwaddr, arp->source_ipaddr, ARP_RESPONSE);
  79          // UCHAR * hwaddr,  本端硬件地址；
  80          // ulong ipaddr,    对端IP地址；
  81          // UCHAR msg_type,  本端ARP类型为: ARP请求还是ARP应答
  82          
  83          void arp_send(UCHAR * hwaddr, ulong ipaddr, UCHAR msg_type)
  84          {
  85   1              UCHAR  * outbuf;
  86   1              ARP_HEADER  * arp;
  87   1               
  88   1         
  89   1         // Allocate memory for entire outgoing message including
  90   1         // eth header. Always 42 bytes
  91   1         outbuf = (UCHAR  *)malloc(42);
  92   1         if (outbuf == NULL)
  93   1         {
  94   2      //      if (debug) serial_send("ARP: Oops, out of memory\r");
  95   2            return;
  96   2         }      
  97   1           
  98   1         // Allow 14 bytes for the ethernet header
  99   1         arp = (ARP_HEADER  *)(outbuf + 14); //定位ARP头
 100   1              
 101   1         arp->hardware_type = DIX_ETHERNET;   //硬件地址类型: DIX_DIX_ETHERNET
 102   1         
 103   1         arp->protocol_type = IP_PACKET;      //上层协议类型: IP_PACKET
 104   1         
 105   1         arp->hwaddr_len = 6;                 //硬件地址长度: 6
 106   1         arp->ipaddr_len = 4;                 //上层协议长度: 6
 107   1         arp->message_type = (uint)msg_type;  //ARP类型: 请求还是应答
 108   1         
 109   1         // My hardware address and IP addresses 
 110   1         memcpy((char *)arp->source_hwaddr, my_hwaddr, 6);
 111   1         arp->source_ipaddr = my_ipaddr;
 112   1      
 113   1         // Destination hwaddr and dest IP addr
 114   1         if (msg_type == ARP_REQUEST)       //如果是ARP请求,向所有主机(EtherADDR = 0)查询指定IP地址的对应硬件地