echo.c

嵌入式RMON,RMON为Remote monitor的缩写,基于SNMP为网络提供主动监控及错误告警,智能交换路由必备协议

/* Beholder RMON ethernet network monitor,Copyright (C) 1993 DNPAP group */
/* See file COPYING 'GNU General Public Licence' for copyright details   */
#include <chain.h>
#include <udp.h>
#include <ip.h>
#include <timer.h>
#include <dtime.h>
#include "echo.h"




static VOID TimerCallback(TIMER_DESCR *timer, ULONG now, void *parm);
static BOOLEAN UdpCallback(UDP_DESCR *udp, CHAIN *chain,
            UDP_HDR *udpHdr, IP_HDR *ipHdr);



ECHO_DESCR *EchoSend(DWORD addr, ULONG timeout, USHORT length, USHORT seqnr,
                ECHO_CALLBACK callback, VOID *parm)
{
    UDP_DESCR   *udp;
    TIMER_DESCR *timer;
    ECHO_DESCR  *echo;

    CHAIN       *chain; 
    
    UDP_HDR     udpHdr;
    IP_HDR      ipHdr;

    WORD        *p;


  
    echo=DnpapMalloc(sizeof(ECHO_DESCR));
    if (echo==0)
    {
        return 0;
    }
    echo->parm=parm;
    echo->callback=callback;
    echo->seqnr=seqnr;
    echo->length=length;
    echo->start=0;
    echo->timer=0;
    echo->udp=0;



    udp=DnpapMalloc(sizeof(UDP_DESCR));
    if (udp==0)
    {
        DnpapFree(echo);
        return 0;
    }
    udp->Rcve=UdpCallback;
    
#ifdef OS2
    udp->locPort=UdpAnyPort(); 
    udp->locAddr=IpRouteFindSrc(addr);  
#else
    udp->locPort=UDP_PORT_ANY; 
    udp->locAddr=UDP_ADDR_ANY;
#endif
    udp->remPort=7;
    udp->remAddr=addr;
    udp->specific=echo;
    if (!UdpRegister(udp))
    {
        DnpapFree(udp);
        DnpapFree(echo);
        return 0;
    }
    echo->udp=udp;


    
    timer=TimerRegister(TimerCallback, echo, timeout, TIMER_FOREVER, TIMER_TYPE_SKIP);
    if (timer==0)
    {
        UdpRemove(udp);
        DnpapFree(udp);
        DnpapFree(echo);
        return 0;
    }
    echo->timer=timer;


    
    chain = ChainAlloc(0,0,length+32,length,32,0);
    if (chain==0)
    {
        TimerRemove(echo->timer);
        UdpRemove(echo->udp);
        DnpapFree(echo->udp);
        DnpapFree(echo);
        return 0;
    }


    
    p = (WORD *)ChainPush(&chain, 2);
    *p = IpH2NWord(echo->seqnr);



    ipHdr.src=udp->locAddr;
    ipHdr.dst=udp->remAddr;
    ipHdr.options=0;
    ipHdr.iol=0;

    udpHdr.src=udp->locPort;
    udpHdr.dst=udp->remPort;
    
    echo->start=TimeUsec();
    
    if (!UdpSend(chain, &udpHdr, &ipHdr, udp))
    {
        ChainFree(chain);
        TimerRemove(echo->timer);
        UdpRemove(echo->udp);
        DnpapFree(echo->udp);
        DnpapFree(echo);
        return 0;
    }
    
    ChainFree(chain);
    return echo;
}



VOID EchoAbort(ECHO_DESCR *echo)
{
    if (echo==0)
        return;
    
    TimerRemove(echo->timer);
    UdpRemove(echo->udp);
    DnpapFree(echo->udp);
    DnpapFree(echo);
}



static VOID TimerCallback(TIMER_DESCR *timer, ULONG now, void *parm)
{
    ECHO_DESCR *echo;
    
    

    echo = parm;

    echo->callback(echo, -1UL, echo->seqnr, echo->parm);

    EchoAbort(echo);
}


static BOOLEAN UdpCallback(UDP_DESCR *udp, CHAIN *chain,
            UDP_HDR *udpHdr, IP_HDR *ipHdr)
{
    ECHO_DESCR *echo;
    WORD       *p;
    
    echo = udp->specific;

    p = (WORD *)ChainPop(&chain, 2);
    if (IpN2HWord(*p)!=echo->seqnr)
    {
        DnpapMessage(DMC_WARNING, ECHO_ERROR, "Wrong sequence number");
        return TRUE;
    }
    
    if (ChainLength(chain)!=echo->length)
    {
        DnpapMessage(DMC_WARNING, ECHO_ERROR, "Wrong length");
        return TRUE;
    }

    echo->callback(echo, TimeUsec()-echo->start, echo->seqnr, echo->parm);

    EchoAbort(echo);

    return TRUE;
}