arp.lst

一个通过8051来控制8019上网的程序 该程序已经通过并成功用于键盘

C51 COMPILER V7.06   ARP                                                                   06/26/2004 13:41:25 PAGE 1   


C51 COMPILER V7.06, COMPILATION OF MODULE ARP
OBJECT MODULE PLACED IN ARP.OBJ
COMPILER INVOKED BY: C:\Keil\C51\BIN\C51.EXE ARP.C LARGE BROWSE DEBUG OBJECTEXTEND

stmt level    source

   1          //-----------------------------------------------------------------------------
   2          // Net ARP.C
   3          //
   4          // This module handles ARP messages and ARP resolution and manages
   5          // the ARP cache. Refer to RFC 826 and RFC 1122
   6          //-----------------------------------------------------------------------------
   7          #include <string.h>
   8          #include <stdlib.h>
   9          #include <stdio.h>
  10          #include <reg89C58.h>
  11          #include "net.h"
  12          #include "eth.h"
  13          #include "ip.h"
  14          #include "arp.h"
  15          
  16          
  17          
  18          extern WAIT xdata wait;
  19          extern UCHAR data my_hwaddr[];
  20          extern UCHAR code broadcast_hwaddr[]; 
  21          extern ULONG data my_ipaddr;
  22          extern ULONG idata my_subnet;
  23          extern ULONG idata gateway_ipaddr;
  24          extern UCHAR idata debug;
  25          ARP_CACHE xdata arp_cache[CACHESIZE];
  26          UCHAR waiting_for_arp;
  27          
  28          
  29          
  30          void init_arp(void)
  31          {
  32   1              memset(arp_cache, 0, sizeof(arp_cache)); 
  33   1              memset(&wait, 0, sizeof(wait));
  34   1              waiting_for_arp = FALSE;
  35   1      }
  36          
  37          
  38          
  39          
  40          //------------------------------------------------------------------------
  41          //      This is called every 60 seconds to age the ARP cache
  42          // If an entry times out then it is deleted from the cache
  43          // See "TCP/IP Illustrated, Volume 1" Sect 4.3
  44          //------------------------------------------------------------------------
  45          void age_arp_cache(void)
  46          {
  47   1              UCHAR i;
  48   1              
  49   1         for (i=0; i < CACHESIZE; i++)
  50   1         {
  51   2            if ((arp_cache[i].ipaddr != 0) && (arp_cache[i].timer))
  52   2            {
  53   3               arp_cache[i].timer--;
  54   3                              if (arp_cache[i].timer == 0)
  55   3               {
C51 COMPILER V7.06   ARP                                                                   06/26/2004 13:41:25 PAGE 2   

  56   4                                      // Timed out so clear out cache entry
  57   4                                      // Do not need to zero hwaddr
  58   4                                      arp_cache[i].ipaddr = 0;
  59   4         //         if (debug) printf("ARP: Aged out a cache entry\n");
  60   4                              }
  61   3                      }
  62   2         }
  63   1      }
  64          
  65          
  66          
  67          
  68          //------------------------------------------------------------------------
  69          // This allocates memory for the entire outgoing message,
  70          // including eth and ip headers, then builds an outgoing
  71          // ARP response message
  72          // See "TCP/IP Illustrated, Volume 1" Sect 4.4
  73          //------------------------------------------------------------------------
  74          void arp_send(UCHAR * hwaddr, ULONG ipaddr, UCHAR msg_type)
  75          {
  76   1              UCHAR xdata * outbuf;
  77   1              ARP_HEADER xdata * arp;
  78   1               
  79   1         
  80   1         // Allocate memory for entire outgoing message including
  81   1         // eth header. Always 42 bytes
  82   1         outbuf = (UCHAR xdata *)malloc(42);
  83   1         if (outbuf == NULL)
  84   1         {
  85   2        //    if (debug) printf("ARP: Oops, out of memory\r");
  86   2            return;
  87   2         }      
  88   1           
  89   1         // Allow 14 bytes for the ethernet header
  90   1         arp = (ARP_HEADER xdata *)(outbuf + 14);
  91   1              
  92   1              arp->hardware_type = DIX_ETHERNET; 
  93   1         arp->protocol_type = IP_PACKET;
  94   1         arp->hwaddr_len = 6;
  95   1              arp->ipaddr_len = 4;               
  96   1         arp->message_type = (UINT)msg_type;
  97   1         
  98   1         // My hardware address and IP addresses 
  99   1         memcpy(arp->source_hwaddr, my_hwaddr, 6);
 100   1         arp->source_ipaddr = my_ipaddr;
 101   1      
 102   1         // Destination hwaddr and dest IP addr
 103   1         if (msg_type == ARP_REQUEST) memset(arp->dest_hwaddr, 0, 6);
 104   1         else memcpy(arp->dest_hwaddr, hwaddr, 6);
 105   1         
 106   1         arp->dest_ipaddr = ipaddr;
 107   1            
 108   1         // If request then the message is a brodcast, if a response then
 109   1         // send to specified hwaddr
 110   1         // ARP payload size is always 28 bytes
 111   1              if (msg_type == ARP_REQUEST) eth_send(outbuf, broadcast_hwaddr, ARP_PACKET, 28);
 112   1         else eth_send(outbuf, hwaddr, ARP_PACKET, 28);
 113   1      }
 114          
 115          
 116          
 117          //------------------------------------------------------------------------
C51 COMPILER V7.06   ARP                                                                   06/26/2004 13:41:25 PAGE 3   

 118          // This re-sends an ARP request if there was no response to
 119          // the first one.        It is called every 0.5 seconds.  If there
 120          // is no response after 2 re-tries, the datagram that IP was 
 121          // trying to send is deleted
 122          //-----------------------------------------------------------------------
 123          void arp_retransmit(void)
 124          {
 125   1              static UCHAR idata retries = 0; 
 126   1              
 127   1              if ((waiting_for_arp) && (wait.timer))
 128   1              {
 129   2                      wait.timer--;
 130   2                      if (wait.timer == 0)
 131   2                      {
 132   3                              retries++;
 133   3                              if (retries <= 2)
 134   3                              {
 135   4                      //              if (debug) printf("ARP: Re-sending ARP broadcast\n");
 136   4                                      arp_send(NULL, wait.ipaddr, ARP_REQUEST);
 137   4                                      wait.timer = ARP_TIMEOUT;
 138   4                              }
 139   3                              else
 140   3                              {       
 141   4              //                      if (debug) printf("ARP: Gave up waiting for response\n");
 142   4                                      wait.timer = 0;
 143   4                                      waiting_for_arp = 0;
 144   4                                      free(wait.buf);
 145   4                              }
 146   3                      }
 147   2              }
 148   1      }
 149          
 150          
 151          
 152          
 153          //------------------------------------------------------------------------
 154          // Find the ethernet hardware address for the given ip address