#include "u.h"#include "../port/lib.h"#include "mem.h"#include "dat.h"#include "fns.h"#include "../port/error.h" #include "ip.h" static voidnullbind(Ipifc*, int, char**){} static voidnullunbind(Ipifc*){} static voidnullbwrite(Ipifc*, Block *bp, int, uchar*, Routehint*){	freeb(bp);	error("nullbwrite");} Medium nullmedium ={.maxtu=		64*1024,.name=		"null",.bind=		nullbind,.unbind=	nullunbind,.bwrite=	nullbwrite,}; /* used in ipifc to prevent unbind while bind is in progress */Medium unboundmedium ={.maxtu=		64*1024,.name=		"unbound",.bind=		nullbind,.unbind=	nullunbind,.bwrite=	nullbwrite,}; voidnullmediumlink(void){	addipmedium(&nullmedium);}