ICMPV6_PLD_MAXLEN
if (m->m_pkthdr.len >= ICMPV6_PLD_MAXLEN)
m_adj(m, ICMPV6_PLD_MAXLEN - m->m_pkthdr.len);
mcopy = m_copym(m, 0, imin(m->m_pkthdr.len, ICMPV6_PLD_MAXLEN),