ip.lst.svn-base

数字广播系统的开发源码

C51 COMPILER V7.06   IP                                                                    07/24/2007 16:32:51 PAGE 1   


C51 COMPILER V7.06, COMPILATION OF MODULE IP
OBJECT MODULE PLACED IN E:\NETBRO~1\TRUNK\NETBRO~1\VW\IP.OBJ
COMPILER INVOKED BY: C:\Keil\C51\BIN\C51.EXE E:\NETBRO~1\TRUNK\NETBRO~1\VW\IP.C DB SB OE

stmt level    source

   1          /*
   2          
   3           */
   4          
   5          #include "GloblDef.h"
   6          #include "TCPIPmem.h"
   7          #include "IP.h"
   8          #include "icmp.h"
   9          #include "Netif.h"
  10          #include "TCP.h"
  11          
  12          /* Check sum calulation. data in buff, size, InSum is initial sum */
  13          unsigned int CheckSum(unsigned int xdata * buff,unsigned int size,unsigned long InSum) reentrant
  14          {
  15   1              /* TO DO:in packet memory high part of short is in low memory. add all data in
  16   1              form of 16 bits get a result of 32 bits, add high 16 bits to low 16 bits two
  17   1              times.  get a 16 bits result then complement it. */
  18   1      
  19   1              unsigned long cksum = InSum;
  20   1      
  21   1              /* sum all unsigned int except the last odd unsigned char(if size is a odd num) */
  22   1              unsigned int xdata * EndBuf = buff + size/2;
  23   1              while(buff < EndBuf)
  24   1              {
  25   2                      /* net order is equeal as host order in mirochip, so no need to change */
  26   2                      cksum += *(buff++);
  27   2              }
  28   1      
  29   1              /**((unsigned int xdata *)CheckSumInParam) = size;
  30   1              *((unsigned int xdata *)(CheckSumInParam+2)) = buff;
  31   1              asmAddCheckSum();
  32   1              cksum = CheckSumOutParm;
  33   1              */
  34   1      
  35   1              /* if has last odd unsigned char. use this unsigned char as the high part of 16 bits, and add. */
  36   1              if((size & 0x0001) != 0)
  37   1                      cksum += (*buff) & 0xff00;
  38   1      
  39   1              cksum = (cksum >> 16) + (cksum & 0xffff);
  40   1              cksum += (cksum >>16);
  41   1              return (unsigned int)(~cksum);
  42   1      }
  43          
  44          /* IP input process */
  45          void IPInput(struct SMemHead xdata *MemHead) reentrant
  46          {
  47   1              struct SIPHead xdata *pIPHead;
  48   1              struct SNetIf  xdata *pNetIf;           /* for search netif list */
  49   1      
  50   1              pIPHead = (struct SIPHead xdata *)(MemHead->pStart);
  51   1      
  52   1              /* check ip version */
  53   1              if(IP_VERSION(pIPHead) != IP_VERSION_4)
  54   1              {
  55   2                      MemFree(MemHead);
C51 COMPILER V7.06   IP                                                                    07/24/2007 16:32:51 PAGE 2   

  56   2                      return;
  57   2              }
  58   1      
  59   1              /* if checksum is ok */
  60   1              if(CheckSum((unsigned int xdata *)pIPHead,(unsigned int)IP_HEAD_LEN(pIPHead),0) != 0)
  61   1              {
  62   2                      MemFree(MemHead);
  63   2                      return;
  64   2              }
  65   1      
  66   1              /* ip packet with options is not supported */
  67   1              if(IP_HEAD_LEN(pIPHead) != IP_HEAD_MIN_LEN)
  68   1              {
  69   2                      MemFree(MemHead);
  70   2                      return;
  71   2              }
  72   1      
  73   1              /* ip packet fragmented is not supported */
  74   1              if((pIPHead->FragmentFlag_Offset & IP_FRAGMENT_OFFSET_MASK)!= 0)
  75   1              {
  76   2                      MemFree(MemHead);
  77   2                      return;
  78   2              }
  79   1      
  80   1      
  81   1              /* if this packet for us. check all the netif. if a host
  82   1              has tow device(tow ip). This packet may come from one device
  83   1              but send for the IP of the other deviec. In this case we should
  84   1              not drop or forward this packet */
  85   1      
  86   1              /* if this packet is not for us. forward it */
  87   1              if((pNetIf = NetIfFindIP(pIPHead->IPDest)) == NULL)
  88   1              {
  89   2                      #ifdef IP_ENABLE_FORWARD        /* if act as a router */
                              /* We should decrease the IPHead->ttl */
                              if(pIPHead->LifeLength != 0)
                              {
                                      pIPHead->LifeLength--;
              
                                      /* recaculate IP head checksum. there is a easy method
                                      to recaculate, leave for later version improvment */
                                      CheckSum((unsigned int xdata *)pIPHead,(unsigned int)IP_HEAD_LEN(pIPHead),0);
              
                                      /* find a rout( a interface ) */
                                      if((pNetIf = NetIfFindRout(pIPHead->IPDest)) != NULL)
                                      {
                                              /* forward. send it through this interface. if return FALSE, we
                                              do not care, the soure of the packet will deel with it. */
                                              pNetIf->output(MemHead,pNetIf,pIPHead->IPDest);
                                      }
                              }
                              #endif
 108   2      
 109   2                      MemFree(MemHead);
 110   2                      return;
 111   2              }
 112   1              else
 113   1              {
 114   2                      /* MemHead->pStart set to point uper layer */
 115   2                      MemHead->pStart += sizeof(struct SIPHead);
 116   2      
 117   2                      /* pass to the uper layer */
C51 COMPILER V7.06   IP                                                                    07/24/2007 16:32:51 PAGE 3   

 118   2                      switch(pIPHead->Protocol)
 119   2                      {
 120   3                      case IP_PROTOCOL_TCP:
 121   3                              //只调试网络驱动和ICMP
 122   3                              //TCPInput(MemHead);
 123   3                              break;
 124   3      #if     ICMP_EN
 125   3                      case IP_PROTOCOL_ICMP:
 126   3                              ICMPInput(MemHead);
 127   3                              break;
 128   3      #endif
 129   3                      default:
 130   3                              MemFree(MemHead);
 131   3                      }
 132   2              }
 133   1      }
 134          
 135          /* out put a ip packet,NOTE:MemHead->pStart point to IPHead.
 136          IPScr IPDest Protocol TotalLen is already filled at uper layer.
 137          To do so TCPCheckSum is easy to generate and pass augument to
 138          IPOutput is easyer.
 139          return :
 140                  TURE: send the packt successful. */
 141          unsigned char IPOutput(struct SMemHead xdata * MemHead) reentrant
 142          {
 143   1              struct SNetIf  xdata *pNetIf;
 144   1              struct SIPHead xdata *pIPHead;
 145   1              unsigned int tCheckSum;
 146   1      
 147   1              pIPHead = (struct SIPHead xdata *)(MemHead->pStart);
 148   1      
 149   1              /* found a rout */
 150   1              if((pNetIf = NetIfFindRout(pIPHead->IPDest)) != NULL)