#include <lib/root.h>#include <lib/string.h>#include <net/inet/ip.h>#include <net/lib/pkt.h>#include "loop.h"loopnetdev_t *loopnetdev;loopnetdev_t::loopnetdev_t(){	strcpy(name, "lo");	/* hardware address make no sense for loop device */	hwhdrlen = 0;	mtu = ETHMTU;	praddr = mkipaddr(127, 0, 0, 1);	netmask = mkipaddr(255, 0, 0, 0);}loopnetdev_t::~loopnetdev_t(){}int loopnetdev_t::output(pkt_t* pkt, u32_t daddr){	ethhdr_t * eh = (ethhdr_t*) pkt->addhead(sizeof(ethhdr_t));	eh->proto = htons(ETHPIP);	input(pkt);        return 0;}