chksumtest.c

实现在ARM上的ICP/IP功能的源代码。

#include "typedef.h"
#include "utilities.h"
#include "ip.h"

//#define disno
u16_t ncs(u16_t *buf, u16_t len,u32_t insum)
{
#ifdef disno
//for()
u16_t *p=buf,i=0,l=len;
u8_t *b;
#endif

     u32_t sum = insum;
     u16_t *wp = (u16_t *) buf;
     
#ifdef disno
Uart_Printf("\nIP CHECK SUM::\n");
for(b=(BYTE*)buf,i=0;i<len;++i,++b){
if (0==i%10)Uart_Printf("\n");
Uart_Printf("  0x%x",*(u8_t*)b);
}
#endif
    /* Sum up 16 bit values. */
    while (len > 1) {sum += *wp++;len -= 2;}
    if (len) {
#ifdef debug_checksum
Uart_Printf("\nTCPCHECKSUM: there is an odd data...\n");
#endif 
        sum += *(u8_t*) wp;}
    while (sum >> 16) {sum = (u16_t)sum + (sum >> 16);} 
    return ((u16_t)(~sum&0xffff));
}
__packed struct plmm{
u32_t a;//2
u32_t b;//2
u8_t c;//
u8_t d;//1
u16_t e;//1
}pt;

WORD TCPCheckSum(struct SIPHead*pIPHead,WORD TCPSize)
{
    //<<<<<<<<<<<<<<<<<
    u16_t i=0,lend,len=TCPSize ;
    u8_t*b ;
    //>>>>>>>>>>>>>>>>>>
 //   #ifdef disno
    //<<<<<<<<<<<<<<<<<<
    u32_t acc=0 ;
    u16_t*p,*wp ;
    //>>>>>>>>>>>>>>>>>>
  //  #endif 
    pt.a = pIPHead->IPScr ;
    pt.b = pIPHead->IPDest ;
    pt.c = 0 ;
    pt.d = pIPHead->Protocol ;
    pt.e = htons (TCPSize);
    lend = len;
    p=(u16_t*)&pt ;

    acc=0 ;
    for(i=0;i<6;++i)
    acc+=*(u16_t*)p++;
    
    wp=(u16_t*)((u8_t*)pIPHead+IP_HEAD_MIN_LEN);
    while(len>1)
    {
        acc+=*wp++;
        len-=2;
    }
    if(len)
    {
    #ifdef debu_checksum
        Uart_Printf("\nETHNUTCS: there is an odd data...\n");
    #endif 
        acc+=*(u8_t*)wp ;
    }
    while(acc>>16)
    {
        acc=(u16_t)acc+(acc>>16);
    }
#ifdef disno
    ////<<<<<<<<<<<<<<<<<<<
    Uart_Printf("\nfirst::: TCPCheckSum::\n");
    for(b=(BYTE*)((BYTE*)pIPHead+IP_HEAD_MIN_LEN),i=0;i<lend;++i,++b)
    {
        if(0==i%10)Uart_Printf("\n");
        Uart_Printf("  0x%x",*(u8_t*)b);
    }
#endif
    ////>>>>>>>>>>>>>>>>>>>.
     return htons((u16_t)(~acc&0xffff));
}