Function ng_ppp_get_packet

freebsd/netgraph/ng_ppp.c:1705–1736

* Pull a completed packet off the head of the incoming fragment queue. * This assumes there is a completed packet there to pull off. */

 * This assumes there is a completed packet there to pull off.
 */
static void
ng_ppp_get_packet(node_p node, struct mbuf **mp)
{
	const priv_p priv = NG_NODE_PRIVATE(node);
	struct ng_ppp_frag *qent, *qnext;
	struct mbuf *m = NULL, *tail;

	qent = TAILQ_FIRST(&priv->frags);
	KASSERT(!TAILQ_EMPTY(&priv->frags) && qent->first,
	    ("%s: no packet", __func__));
	for (tail = NULL; qent != NULL; qent = qnext) {
		qnext = TAILQ_NEXT(qent, f_qent);
		KASSERT(!TAILQ_EMPTY(&priv->frags),
		    ("%s: empty q", __func__));
		TAILQ_REMOVE(&priv->frags, qent, f_qent);
		if (tail == NULL)
			tail = m = qent->data;
		else {
			m->m_pkthdr.len += qent->data->m_pkthdr.len;
			tail->m_next = qent->data;
		}
		while (tail->m_next != NULL)
			tail = tail->m_next;
		if (qent->last) {
			qnext = NULL;
			/* Bump MSEQ if necessary */
			ng_ppp_bump_mseq(node, qent->seq);
		}
		TAILQ_INSERT_HEAD(&priv->fragsfree, qent, f_qent);
	}
	*mp = m;
}

/*
 * Trim fragments from the queue whose packets can never be completed.