/* icmp_in.c - icmp_in */

#include <conf.h>
#include <kernel.h>
#include <network.h>

/*------------------------------------------------------------------------
 *  icmp_in  -  handle ICMP packet coming in from the network
 *------------------------------------------------------------------------
 */
int icmp_in(pni, pep)
struct	netif	*pni;		/* not used */
struct	ep	*pep;
{
    struct	ip	*pip;
    struct	icmp	*pic;
    int		i, len;

    pip = (struct ip *)pep->ep_data;
    pic = (struct icmp *) pip->ip_data;

#ifdef notdef
    { STATWORD ps;
    kprintf("icmp_in:\n");
    pdump(pep);
    }
#endif
    len = pip->ip_len - IP_HLEN(pip);
    if (cksum(pic, len)) {
	kprintf("icmp_in: BAD CKSUM %X ic_cksum %X len %d\n", cksum(pic, len),
		pic->ic_cksum, len);
	IcmpInErrors++;
	freebuf(pep);
	return SYSERR;
    }
    IcmpInMsgs++;
    switch(pic->ic_type) {
    case ICT_ECHORQ:
	IcmpInEchos++;
	return icmp(ICT_ECHORP, 0, pip->ip_src, pep, 0);
    case ICT_MASKRQ:
	IcmpInAddrMasks++;
	if (!gateway) {
	    freebuf(pep);
	    return OK;
	}
	pic->ic_type = (char) ICT_MASKRP;
	*(IPaddr *)pic->ic_data = netmask(pip->ip_dst);
	break;
    case ICT_MASKRP:
	IcmpInAddrMaskReps++;
	for (i=0; i<Net.nif; ++i)
	    if (nif[i].ni_ip == pip->ip_dst)
		break;
	if (i != Net.nif) {
	    setmask(i, *(IPaddr *)pic->ic_data);
	    send(pic->ic_id, ICT_MASKRP);
	}
	freebuf(pep);
	return OK;
    case ICT_ECHORP:
	IcmpInEchoReps++;
	if (send(pic->ic_id, pep) != OK)
	    freebuf(pep);
	return OK;
    case ICT_REDIRECT:
	IcmpInRedirects++;
	icredirect(pep);
	return OK;
    case ICT_DESTUR: IcmpInDestUnreachs++;	freebuf(pep); return OK;
    case ICT_SRCQ:	 IcmpInSrcQuenchs++;	freebuf(pep); return OK;
    case ICT_TIMEX:	 IcmpInTimeExcds++;	freebuf(pep); return OK;
    case ICT_PARAMP: IcmpInParmProbs++;	freebuf(pep); return OK;
    case ICT_TIMERQ: IcmpInTimestamps++;	freebuf(pep); return OK;
    case ICT_TIMERP: IcmpInTimestampReps++;	freebuf(pep); return OK;
    default:
	IcmpInErrors++;
	freebuf(pep);
	return OK;
    }
    icsetsrc(pip);

    len = pip->ip_len - IP_HLEN(pip);

    pic->ic_cksum = 0;
    pic->ic_cksum = cksum(pic, len);

    IcmpOutMsgs++;
    ipsend(pip->ip_dst, pep, len, IPT_ICMP, IPP_INCTL, IP_TTL);
    return OK;
}