/* * ensure that [off, off + len) is contiguous on the mbuf chain "m". * packet chain before "off" is kept untouched. * if offp == NULL, the target will start at <retval, 0> on resulting chain. * if offp != NULL, the target will start at <retval, *offp> on resulting chain. * * on error return (NULL return value), original "m" will be freed. * * XXX M_TRAILINGSPACE/M_LEADINGSPACE on shared cluster (sharedcluster) */