Function ng_ppp_mp_xmit

freebsd/netgraph/ng_ppp.c:1988–2177

* Deliver a frame out on the bundle, i.e., figure out how to fragment * the frame across the individual PPP links and do so. */

 * the frame across the individual PPP links and do so.
 */
static int
ng_ppp_mp_xmit(node_p node, item_p item, uint16_t proto)
{
	const priv_p priv = NG_NODE_PRIVATE(node);
	const int hdr_len = priv->conf.xmitShortSeq ? 2 : 4;
	int distrib[NG_PPP_MAX_LINKS];
	int firstFragment;
	int activeLinkNum;
	struct mbuf *m;
	int	plen;
	int	frags;
	int32_t	seq;

	/* At least one link must be active */
	if (priv->numActiveLinks == 0) {
		NG_FREE_ITEM(item);
		return (ENETDOWN);
	}

	/* Save length for later stats. */
	plen = NGI_M(item)->m_pkthdr.len;

	if (!priv->conf.enableMultilink) {
		return (ng_ppp_link_xmit(node, item, proto,
		    priv->activeLinks[0], plen));
	}

	/* Check peer's MRRU for this bundle. */
	if (plen > priv->conf.mrru) {
		NG_FREE_ITEM(item);
		return (EMSGSIZE);
	}

	/* Extract mbuf. */
	NGI_GET_M(item, m);

	/* Prepend protocol number, possibly compressed. */
	if ((m = ng_ppp_addproto(m, proto, 1)) == NULL) {
		NG_FREE_ITEM(item);
		return (ENOBUFS);
	}

	/* Clear distribution plan */
	bzero(&distrib, priv->numActiveLinks * sizeof(distrib[0]));

	mtx_lock(&priv->xmtx);

	/* Round-robin strategy */
	if (priv->conf.enableRoundRobin) {
		activeLinkNum = priv->lastLink++ % priv->numActiveLinks;
		distrib[activeLinkNum] = m->m_pkthdr.len;
		goto deliver;
	}

	/* Strategy when all links are equivalent (optimize the common case) */
	if (priv->allLinksEqual) {
		int	numFrags, fraction, remain;
		int	i;