mb_dupcl
mb_dupcl(mr, mb->m_next);
mb_dupcl(m, m0);
mb_dupcl(tail, m0);
mb_dupcl(n, m);
mb_dupcl(n, m);
mb_dupcl(n, m);
mb_dupcl(n, m);
mb_dupcl(n, m);
mb_dupcl(n, m);
mb_dupcl(n, m);
mb_dupcl(n, m);
void mb_dupcl(struct mbuf *, struct mbuf *);