icmp.c

实现在ARM上的ICP/IP功能的源代码。

#include "debug.h"
#include "true_false.h"
#include "stdlib.h"
#include "typedef.h"
#include "mem_man.h"
#include "rtl8019.h"
#include "netif.h"
#include "etherif.h"
#include "ip.h"
#include "arp.h"
#include "utilities.h"
#include "tcp.h"
#include "icmp.h"

static u16_t GlobalID=0;
static u8_t state=PING_OK;
/* MemHead->pStart is point to ICMP hea */
void ICMPInput(struct SMemHead*MemHead)
{
    IP_ADDR ipaddr ;
    struct SIPHead*pIPHead ;
    struct SICMPEchoHead*pICMPHead ;
    /* which type of icmp */
    switch(((struct SICMPEchoHead*)(MemHead->pStart))->type)
    {
        case ICMP_TYPE_QUERY :
        
        /* chage type */
        ((struct SICMPEchoHead*)(MemHead->pStart))->type=ICMP_TYPE_REPLY ;
        
        /* adjust checksum. refer to lwip: if change type from 8 to 0,
                		for checksum, that is increasing 0x8000 and add flowed hight bit
                		to bit 0.*/
        if(((struct SICMPEchoHead*)(MemHead->pStart))->CheckSum>=htons(0xffff-(((WORD)ICMP_TYPE_QUERY)<<8)))
        ((struct SICMPEchoHead*)(MemHead->pStart))->CheckSum+=htons(((WORD)ICMP_TYPE_QUERY)<<8)+1 ;
        else 
        ((struct SICMPEchoHead*)(MemHead->pStart))->CheckSum+=htons(((WORD)ICMP_TYPE_QUERY)<<8);
        
        /*
                		 *send this packet back, first fill some of IPHead field
                		 */
        
        /* dec pStart and get ip head */
        pIPHead=(struct SIPHead*)(MemHead->pStart-=IP_HEAD_MIN_LEN);
        
        /* exchange ipdest and ipscr */
        ipaddr=pIPHead->IPDest ;
        pIPHead->IPDest=pIPHead->IPScr ;
        pIPHead->IPScr=ipaddr ;
        
        /* ip total length not change */
        
        /* protocol */
        pIPHead->Protocol=IP_PROTOCOL_ICMP ;
        
        IPOutput(MemHead);
        
        /* whether send success or not free this packet */
        MemFree(MemHead);
        
        break ;
        case ICMP_TYPE_REPLY :
        /*ICMP校验和只覆盖ICMP报文*/
        pICMPHead=(struct SICMPEchoHead*)(MemHead->pStart) ;
        if(CheckSum((u16_t*)pICMPHead,MemHead->pEnd-MemHead->pStart,0)!=0)
        {
        #ifdef debug_icmp
            Uart_Printf("ICMP:RCV A REPLY FRAME BUT CHECKSUM IS ERROR!\n");
        #endif 
        }
        else 
        {
        #ifdef debug_icmp
           Uart_Printf("globalid =%d seq=%d\n",GlobalID,ntohs(pICMPHead->seq));
        #endif	
        	if(GlobalID==ntohs(pICMPHead->seq))
        	{
          		if(state==PING_WAIT)
            	state=PING_OK;
        		/*the ringht ping_reply we are look for*/
        	}
        }
        MemFree(MemHead);
        break ;
        default :
        MemFree(MemHead);
    }
}

BOOL PINGOut(IP_ADDR IPScr,IP_ADDR IPDest,u16_t len)
{
    struct SMemHead*MemHead ;
    struct SIPHead*pIPHead ;
    struct SICMPEchoHead*pICMPHead ;
    BOOL ret=FALSE;
    if (len>1450) len=1450;
    /*alloate some memory for the ping packet*/
    MemHead=MemAllocate(len+ICMP_HEAD_MIN_LEN+IP_HEAD_MIN_LEN+NETIF_HEAD_MAX_LEN);
    if(MemHead==NULL) return FALSE ;
    /*fill icmp head*/
    pICMPHead=(struct SICMPEchoHead*)
    (MemHead->pStart+IP_HEAD_MIN_LEN+NETIF_HEAD_MAX_LEN);
    
    pICMPHead->type=ICMP_TYPE_QUERY ;
    pICMPHead->ICMPCode=0 ;
    pICMPHead->CheckSum=0 ;
    pICMPHead->id=htons(512) ;
    pICMPHead->seq=htons(++GlobalID);
    pICMPHead->CheckSum=CheckSum((u16_t*)(u8_t*)pICMPHead,
    MemHead->pEnd-MemHead->pStart-IP_HEAD_MIN_LEN-NETIF_HEAD_MAX_LEN,
    0);
    /*fill ip head*/
    pIPHead=(struct SIPHead*)(MemHead->pStart+NETIF_HEAD_MAX_LEN);
    pIPHead->IPDest=htonl(IPDest) ;
    pIPHead->IPScr=htonl(IPScr) ;
    pIPHead->TotalLen=htons(MemHead->pEnd-MemHead->pStart-NETIF_HEAD_MAX_LEN);
    pIPHead->Protocol=IP_PROTOCOL_ICMP ;
    
    MemHead->pStart=(BYTE*)pIPHead ;
	state=PING_WAIT;
    ret=IPOutput(MemHead);
            /* whether send success or not free this packet */
    MemFree(MemHead);
    return ret;
} 

u8_t get_state(){
return state;
}