Function get_export9_dgram

freebsd/netgraph/netflow/netflow_v9.c:368–435

* Detach export datagram from fib instance, if there is any. * If there is no, allocate a new one. */

 * If there is no, allocate a new one.
 */
item_p
get_export9_dgram(priv_p priv, fib_export_p fe, struct netflow_v9_packet_opt **tt)
{
	item_p	item = NULL;
	struct netflow_v9_packet_opt *t = NULL;

	mtx_lock(&fe->export9_mtx);
	if (fe->exp.item9 != NULL) {
		item = fe->exp.item9;
		fe->exp.item9 = NULL;
		t = fe->exp.item9_opt;
		fe->exp.item9_opt = NULL;
	}
	mtx_unlock(&fe->export9_mtx);

	if (item == NULL) {
		struct netflow_v9_export_dgram *dgram;
		struct mbuf *m;
		uint16_t mtu = priv->mtu;

		/* Allocate entire packet at once, allowing easy m_append() calls */
		m = m_getm(NULL, mtu, M_NOWAIT, MT_DATA);
		if (m == NULL)
			return (NULL);

		t = malloc(sizeof(struct netflow_v9_packet_opt), M_NETFLOW_GENERAL, M_NOWAIT | M_ZERO);
		if (t == NULL) {
			m_free(m);
			return (NULL);
		}

		item = ng_package_data(m, NG_NOFLAGS);
		if (item == NULL) {
			free(t, M_NETFLOW_GENERAL);
			return (NULL);
		}

		dgram = mtod(m, struct netflow_v9_export_dgram *);
		dgram->header.count = 0;
		dgram->header.version = htons(NETFLOW_V9);
		/* Set mbuf current data length */
		m->m_len = m->m_pkthdr.len = sizeof(struct netflow_v9_header);

		t->count = 0;
		t->mtu = mtu;
		t->flow_header = m->m_len;

		/*
		 * Check if we need to insert templates into packet
		 */
		
		struct netflow_v9_flowset_header	*fl;

		if ((time_uptime >= priv->templ_time + fe->templ_last_ts) ||
				(fe->sent_packets >= priv->templ_packets + fe->templ_last_pkt)) {
			fe->templ_last_ts = time_uptime;
			fe->templ_last_pkt = fe->sent_packets;