1 files changed, 138 insertions, 0 deletions
diff --git a/eigrpd/eigrp_metric.c b/eigrpd/eigrp_metric.c
new file mode 100644
index 0000000..1662f48
--- /dev/null
+++ b/eigrpd/eigrp_metric.c
@@ -0,0 +1,138 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * EIGRP Metric Math Functions.
+ * Copyright (C) 2013-2016
+ * Authors:
+ *   Donnie Savage
+ */
+
+#include <zebra.h>
+
+#include "eigrpd/eigrp_structs.h"
+#include "eigrpd/eigrpd.h"
+#include "eigrpd/eigrp_types.h"
+#include "eigrpd/eigrp_metric.h"
+
+eigrp_scaled_t eigrp_bandwidth_to_scaled(eigrp_bandwidth_t bandwidth)
+{
+	eigrp_bandwidth_t scaled = EIGRP_BANDWIDTH_MAX;
+
+	if (bandwidth != EIGRP_BANDWIDTH_MAX) {
+		scaled = (EIGRP_CLASSIC_SCALER * EIGRP_BANDWIDTH_SCALER);
+		scaled = scaled / bandwidth;
+
+		scaled = scaled ? scaled : EIGRP_BANDWIDTH_MIN;
+	}
+
+	scaled = (scaled < EIGRP_METRIC_MAX) ? scaled : EIGRP_METRIC_MAX;
+	return (eigrp_scaled_t)scaled;
+}
+
+eigrp_bandwidth_t eigrp_scaled_to_bandwidth(eigrp_scaled_t scaled)
+{
+	eigrp_bandwidth_t bandwidth = EIGRP_BANDWIDTH_MAX;
+
+	if (scaled != EIGRP_CLASSIC_MAX) {
+		bandwidth = (EIGRP_CLASSIC_SCALER * EIGRP_BANDWIDTH_SCALER);
+		bandwidth = scaled * bandwidth;
+		bandwidth = (bandwidth < EIGRP_METRIC_MAX)
+				    ? bandwidth
+				    : EIGRP_BANDWIDTH_MAX;
+	}
+
+	return bandwidth;
+}
+
+eigrp_scaled_t eigrp_delay_to_scaled(eigrp_delay_t delay)
+{
+	delay = delay ? delay : EIGRP_DELAY_MIN;
+	return delay * EIGRP_CLASSIC_SCALER;
+}
+
+eigrp_delay_t eigrp_scaled_to_delay(eigrp_scaled_t scaled)
+{
+	scaled = scaled / EIGRP_CLASSIC_SCALER;
+	scaled = scaled ? scaled : EIGRP_DELAY_MIN;
+
+	return scaled;
+}
+
+eigrp_metric_t eigrp_calculate_metrics(struct eigrp *eigrp,
+				       struct eigrp_metrics metric)
+{
+	eigrp_metric_t composite = 0;
+
+	if (metric.delay == EIGRP_MAX_METRIC)
+		return EIGRP_METRIC_MAX;
+
+	/*
+	 * EIGRP Composite =
+	 * {K1*BW+[(K2*BW)/(256-load)]+(K3*delay)}*{K5/(reliability+K4)}
+	 */
+
+	if (eigrp->k_values[0])
+		composite += ((eigrp_metric_t)eigrp->k_values[0] *
+			      (eigrp_metric_t)metric.bandwidth);
+	if (eigrp->k_values[1])
+		composite += (((eigrp_metric_t)eigrp->k_values[1] *
+			       (eigrp_metric_t)metric.bandwidth) /
+			      (256 - metric.load));
+	if (eigrp->k_values[2])
+		composite += ((eigrp_metric_t)eigrp->k_values[2] *
+			      (eigrp_metric_t)metric.delay);
+	if (eigrp->k_values[3] && !eigrp->k_values[4])
+		composite *= (eigrp_metric_t)eigrp->k_values[3];
+	if (!eigrp->k_values[3] && eigrp->k_values[4])
+		composite *= ((eigrp_metric_t)eigrp->k_values[4] /
+			      (eigrp_metric_t)metric.reliability);
+	if (eigrp->k_values[3] && eigrp->k_values[4])
+		composite *= (((eigrp_metric_t)eigrp->k_values[4] /
+			       (eigrp_metric_t)metric.reliability) +
+			      (eigrp_metric_t)eigrp->k_values[3]);
+
+	composite =
+		(composite <= EIGRP_METRIC_MAX) ? composite : EIGRP_METRIC_MAX;
+
+	return composite;
+}
+
+eigrp_metric_t
+eigrp_calculate_total_metrics(struct eigrp *eigrp,
+			      struct eigrp_route_descriptor *entry)
+{
+	struct eigrp_interface *ei = entry->ei;
+	eigrp_delay_t temp_delay;
+	eigrp_bandwidth_t bw;
+
+	entry->total_metric = entry->reported_metric;
+	temp_delay = entry->total_metric.delay
+		     + eigrp_delay_to_scaled(ei->params.delay);
+
+	entry->total_metric.delay = temp_delay > EIGRP_METRIC_MAX_CLASSIC
+					    ? EIGRP_METRIC_MAX_CLASSIC
+					    : temp_delay;
+
+	bw = eigrp_bandwidth_to_scaled(ei->params.bandwidth);
+	entry->total_metric.bandwidth = entry->total_metric.bandwidth > bw
+						? bw
+						: entry->total_metric.bandwidth;
+
+	return eigrp_calculate_metrics(eigrp, entry->total_metric);
+}
+
+bool eigrp_metrics_is_same(struct eigrp_metrics metric1,
+			   struct eigrp_metrics metric2)
+{
+	if ((metric1.bandwidth == metric2.bandwidth)
+	    && (metric1.delay == metric2.delay)
+	    && (metric1.hop_count == metric2.hop_count)
+	    && (metric1.load == metric2.load)
+	    && (metric1.reliability == metric2.reliability)
+	    && (metric1.mtu[0] == metric2.mtu[0])
+	    && (metric1.mtu[1] == metric2.mtu[1])
+	    && (metric1.mtu[2] == metric2.mtu[2])) {
+		return true;
+	}
+
+	return false; /* if different */
+}