m_prepend
m = m_prepend(m, txd_len, M_DONTWAIT);
m = m_prepend(m, sizeof(uint32_t), M_DONTWAIT);
m = m_prepend(m, sizeof(*hdr), M_DONTWAIT);
m = m_prepend(m, sizeof(*eh), M_DONTWAIT);
m = m_prepend(m, hlen, M_DONTWAIT);
m = m_prepend(m, ETHER_ALIGN + sizeof(*eh), M_NOWAIT);
m = m_prepend(m, ETHER_ALIGN + sizeof(eh), M_DONTWAIT);
m = m_prepend(m, sizeof(*ip), M_DONTWAIT);
m = m_prepend(m, sizeof(*ip6), M_DONTWAIT);
m = m_prepend(m, hlen, M_DONTWAIT);
m = m_prepend(m, sizeof(*ip), M_DONTWAIT);
m = m_prepend(m, sizeof(*ip6), M_DONTWAIT);
m = m_prepend(m, sizeof(*gh) + sizeof(*eoiph), M_DONTWAIT);
m = m_prepend(m, sizeof(*gh) + sizeof(*seqh) + sizeof(*erspanh),
m = m_prepend(m, sizeof(shim), M_NOWAIT);
m = m_prepend(m, sizeof(shim), M_NOWAIT);
m = m_prepend(m, sizeof(shim), M_NOWAIT);
m = m_prepend(m, sizeof(shim), M_NOWAIT);
m0 = m_prepend(m0, sizeof(*shim), M_NOWAIT);
m0 = m_prepend(m0, sizeof(*shim), M_NOWAIT);
m0 = m_prepend(m0, sizeof(*shim), M_NOWAIT);
m = m_prepend(m, sizeof(*ur), M_DONTWAIT);
m = m_prepend(m, sizeof(*subh), M_DONTWAIT);
m = m_prepend(m, sizeof(*h), M_DONTWAIT);
m = m_prepend(m, sizeof(uint32_t), M_DONTWAIT);
m = m_prepend(m, sizeof(*eh), M_DONTWAIT);
m = m_prepend(m, hlen, M_DONTWAIT);
m = m_prepend(m0, sizeof(*vh), M_DONTWAIT);
m = m_prepend(m, sizeof(*uh), M_DONTWAIT);
m = m_prepend(m, sizeof(*ip), M_DONTWAIT);
m = m_prepend(m, sizeof(*ip6), M_DONTWAIT);
m = m_prepend(m, sizeof(struct ip), M_DONTWAIT);
(m) = m_prepend((m), (plen), (how))
struct mbuf *m_prepend(struct mbuf *, int, int);