m_pktdat
KASSERT(m->m_pktdat <= m->m_data
&& m->m_data <= &m->m_pktdat[MHLEN - m->m_len]);
size_t oldoff = m->m_data - m->m_pktdat;
memmove(&m->m_pktdat[off], m->m_data, m->m_len);
m->m_data = &m->m_pktdat[off];
memmove(m->m_pktdat + sizeof(fcb), m->m_data, m->m_len);
m->m_data = m->m_pktdat;
m->m_data = m->m_pktdat;
#define mtomv(m) ((struct mbuf_vec *)((m)->m_pktdat))
mv = (struct mbuf_vec *)((m)->m_pktdat);
m_new->m_data = m_new->m_pktdat;
if ((void *)m->m_pktdat == (void *)p) {
memmove(m->m_pktdat, m->m_data, m->m_len);
m->m_data = m->m_pktdat;
to->m_data = to->m_pktdat;
to->m_data = to->m_pktdat;
m->m_data = m->m_pktdat;
m->m_data - sizeof(struct ip) < m->m_pktdat)
#define MHLEN ((int)(MSIZE - offsetof(struct _mbuf_dummy, m_pktdat)))
((m)->m_flags & M_PKTHDR) ? (m)->m_pktdat : (m)->m_dat)
offsetof(struct mbuf, m_pktdat) : offsetof(struct mbuf, m_dat))