#include <u.h>#include <libc.h>#include <ip.h> static char zea[6]; intmyetheraddr(uchar *to, char *dev){	Ipifc *ifclist, *ifc;		ifclist = readipifc(nil, nil, -1);	for(ifc=ifclist; ifc; ifc=ifc->next){		if(dev && strcmp(ifc->dev, dev) != 0)			continue;		if(memcmp(zea, ifc->ether, 6) == 0)			continue;		memmove(to, ifc->ether, 6);		freeipifc(ifclist);		return 0;	}	freeipifc(ifclist);	werrstr("no ethernet devices");	return -1;}