m_striphdr
int m_striphdr(struct mbuf *m, int skip, int hlen);
m_striphdr(m, 0, ip->ip_hl << 2);
m_striphdr(m, 0, ip->ip_hl << 2);
m_striphdr(m, 0, skip);
m_striphdr(m, 0, skip);
m_striphdr(m, hlen, sizeof(*udp));
error = m_striphdr(m, skip, ahsize);
error = m_striphdr(m, skip, hlen);
error = m_striphdr(m, skip, hlen);