#

#include	"../h/param.h"
#include	"../h/user.h"

#include	"../h/pkts.h"
#include	"../h/net.h"

#define	NHOST	16

long		mymach = 0x0a120800;
int		mygate = 5;

struct gt_host	hostgates[NHOST];

/* mk_net  put local net hdr on packet
* If packet's foreign inet host equals net
*  connection foreign host, have saved
*  best first hop local dest. in nt_rte
*  (unless first local hop is default
*  gateway); so fill local dest from
*  nt_rte unless nt_rte is NULL.
* Otherwise use net routing routine
*  to decide if better route than
*  via default gateway.
*/  
mk_net(ppkt, nip)
register struct pkt	*ppkt;
register struct netino	*nip;
{
	register short	ldest;

	if (ppkt->pk_inet.ip_dest == nip->nt_fhost.nt_lhost) {
		if (nip->nt_rte != NULL)
			ldest = nip->nt_rte;
		else
			ldest = mygate;
		}
	else {
		ldest = net_rte(ppkt->pk_inet.ip_dest);
		if (ldest == NULL) ldest = mygate;
		}

	if (ldest == NULL) return(ERR);

	ppkt->pk_net.v2_dest = ldest;
	ppkt->pk_net.v2_prot1 = MPHWPROT;
	ppkt->pk_net.v2_prot2 = INETPROT;
	ppkt->pk_net.v2_zero = 0;
}

ch_net(rp)
register struct rcvpkt	*rp;
{
	register struct pkt	*ppkt;

	if ((rp->rp_len < (NETHSIZ + IPHSIZ)) ||
		(rp->rp_len > NETBYTES) ) {
		neterrt(ENETLEN);
		return(FALSE);
		}

	ppkt = &rp->rp_net;
	if ((ppkt->pk_net.v2_prot1 != MPHWPROT) ||
		(ppkt->pk_net.v2_prot2 != INETPROT) ) {
		neterrt(ENETPROT);
		return(FALSE);
		}

	return(TRUE);
}

/* net_rte  compute best first hop local dest.
* Routing rules to foreign host are:
* 1) If foreign host's net/subnet is same as
*    mymach's, send packet directly to host
* 2) If foreign host is exact match w. host
*    in host gate table, send to gate specified
*    in table entry.
* 3) Otherwise, send packet to default gateway.
*/
net_rte(fhost)
long	fhost;
{
	register struct in_name	*pfhost;
	struct in_name		*pmymach;
	register struct gt_host	*hgp, *hgpe;

	if (fhost == NULL) return(NULL);

	pfhost = &fhost;
	pmymach = &mymach;

	if ((pfhost->in_net == pmymach->in_net) &&
		(pfhost->in_snet == pmymach->in_snet))
		return(pfhost->in_host);

	for (hgp = &hostgates[0], hgpe = &hostgates[NHOST];
		hgp < hgpe; hgp++) 
		if (hgp->gt_fhost == fhost)
			return(hgp->gt_gate);

	return(NULL);
}

/* clr_hgate  clear host gateway table and
* recompute first hop local dest. for
* all net inodes
*/
clr_hgate()
{
	register struct gt_host	*hgp, *hgpe;
	register struct netino	*nip;
	register struct in_name	*pmymach;

	for (hgp = &hostgates[0], hgpe = &hostgates[NHOST];
		hgp < hgpe; hgp++) {
		hgp->gt_fhost = NULL;
		hgp->gt_gate = NULL;
		}

	pmymach = &mymach;
	for (nip = neti_que.q_head; nip != NULL;
		nip = nip->nt_forw)
		if ((nip->nt_fhost.nt_inhost.in_net == pmymach->in_net) &&
			(nip->nt_fhost.nt_inhost.in_snet == pmymach->in_snet))
			nip->nt_rte = nip->nt_fhost.nt_inhost.in_host;
		else
			nip->nt_rte = NULL;
}

/* add_hgate  add a host and its gate to host gate table
* if new entry has NULL host or gate or is same
* net/subnet as this machine, return error
* if no free slot try to drop host which is not
* in net inode list
* search net inodes for host, if match update nt_rte
*/
add_hgate(hgatep)
register struct gt_host	*hgatep;
{
	register struct gt_host	*hgp;
	struct gt_host		*hgpe, *hgpsv;
	register struct netino	*nip;
	struct in_name		*pfhost, *pmymach;
	static int		rephost = 0;

	if ((hgatep->gt_fhost == NULL) ||
		(hgatep->gt_gate == NULL))
		return( netu_err(EINVAL) );

	pfhost = &hgatep->gt_fhost;
	pmymach = &mymach;
	if ((pfhost->in_net == pmymach->in_net) &&
		(pfhost->in_snet == pmymach->in_snet))
		return( netu_err(EINVAL) );

	hgpsv = NULL;
	for (hgp = &hostgates[0], hgpe = &hostgates[NHOST];
		hgp < hgpe; hgp++) {
		if (hgp->gt_fhost == hgatep->gt_fhost) {
			hgpsv = hgp;
			break;
			}
		if ( (hgp->gt_fhost == NULL) &&
			(hgpsv == NULL) ) hgpsv = hgp;
		}

	if (hgpsv == NULL) {
		for (hgp = &hostgates[0], hgpe = &hostgates[NHOST];
			hgp < hgpe; hgp++) {
			for (nip = neti_que.q_head; nip != NULL;
				nip = nip->nt_forw)
				if (nip->nt_fhost.nt_lhost ==
					hgp->gt_fhost) break;
			if (nip == NULL) {
				hgpsv = hgp;
				break;
				}
			}
		}

	if (hgpsv == NULL) {
		hgpsv = &hostgates[rephost];
		if (++rephost >= NHOST) rephost = 0;
		}

	hgpsv->gt_fhost = hgatep->gt_fhost;
	hgpsv->gt_gate = hgatep->gt_gate;

	for (nip = neti_que.q_head; nip != NULL;
		nip = nip->nt_forw)
		if (hgatep->gt_fhost == nip->nt_fhost.nt_lhost)
			nip->nt_rte = hgatep->gt_gate;
}

/* def_gate  define default gateway
*/
def_gate(gate)
int	gate;
{
	mygate = gate;
}

/* del_gate  delete a gateway
* if same as default gateway, NULL default gateway
* search host gate table for hosts which use this
*  gate, NULL these entries
* search net inodes for connections which use this
*  gate, NULL nt_rte (unless foreign host is on
*  our net/subnet - a local host can be both a
*  dest. host and a gateway
*/
del_gate(gate)
register int	gate;
{
	register struct gt_host	*hgp;
	struct gt_host		*hgpe;
	register struct netino	*nip;
	struct in_name		*pmymach;

	if (gate == mygate) mygate = NULL;

	for (hgp = &hostgates[0], hgpe = &hostgates[NHOST];
		hgp < hgpe; hgp++) 
		if (hgp->gt_gate == gate) {
			hgp->gt_fhost = NULL;
			hgp->gt_gate = NULL;
			}

	pmymach = &mymach;
	for (nip = neti_que.q_head; nip != NULL;
		nip = nip->nt_forw)
		if (nip->nt_rte == gate) {
			if ((nip->nt_fhost.nt_inhost.in_net == pmymach->in_net) &&
				(nip->nt_fhost.nt_inhost.in_snet == pmymach->in_snet))
				nip->nt_rte = nip->nt_fhost.nt_inhost.in_host;
			else
				nip->nt_rte = NULL;
			}
}