m_copydata
extern void m_copydata __P((struct mbuf *, int, int, caddr_t));
extern void m_copydata __P((mb_t *, int, int, caddr_t));
extern void m_copydata __P((mb_t *, int, int, caddr_t));
# define COPYDATA m_copydata
extern void m_copydata __P((struct mbuf *, int, int, caddr_t));