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1 | /* | |
2 | * EIGRP Metric Math Functions. | |
3 | * Copyright (C) 2013-2016 | |
4 | * Authors: | |
5 | * Donnie Savage | |
6 | * | |
7 | * This file is part of GNU Zebra. | |
8 | * | |
9 | * GNU Zebra is free software; you can redistribute it and/or modify it | |
10 | * under the terms of the GNU General Public License as published by the | |
11 | * Free Software Foundation; either version 2, or (at your option) any | |
12 | * later version. | |
13 | * | |
14 | * GNU Zebra is distributed in the hope that it will be useful, but | |
15 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
17 | * General Public License for more details. | |
18 | * | |
19 | * You should have received a copy of the GNU General Public License along | |
20 | * with this program; see the file COPYING; if not, write to the Free Software | |
21 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
22 | */ | |
23 | ||
24 | #include "eigrpd/eigrp_structs.h" | |
25 | #include "eigrpd/eigrpd.h" | |
26 | #include "eigrpd/eigrp_types.h" | |
27 | #include "eigrpd/eigrp_metric.h" | |
28 | ||
29 | eigrp_scaled_t eigrp_bandwidth_to_scaled(eigrp_bandwidth_t bandwidth) | |
30 | { | |
31 | eigrp_bandwidth_t scaled = EIGRP_BANDWIDTH_MAX; | |
32 | ||
33 | if (bandwidth != EIGRP_BANDWIDTH_MAX) { | |
34 | scaled = (EIGRP_CLASSIC_SCALER * EIGRP_BANDWIDTH_SCALER); | |
35 | scaled = scaled / bandwidth; | |
36 | ||
37 | scaled = scaled ? scaled : EIGRP_BANDWIDTH_MIN; | |
38 | } | |
39 | ||
40 | scaled = (scaled < EIGRP_METRIC_MAX) ? scaled : EIGRP_METRIC_MAX; | |
41 | return (eigrp_scaled_t)scaled; | |
42 | } | |
43 | ||
44 | eigrp_bandwidth_t eigrp_scaled_to_bandwidth(eigrp_scaled_t scaled) | |
45 | { | |
46 | eigrp_bandwidth_t bandwidth = EIGRP_BANDWIDTH_MAX; | |
47 | ||
48 | if (scaled != EIGRP_CLASSIC_MAX) { | |
49 | bandwidth = (EIGRP_CLASSIC_SCALER * EIGRP_BANDWIDTH_SCALER); | |
50 | bandwidth = scaled * bandwidth; | |
51 | bandwidth = (bandwidth < EIGRP_METRIC_MAX) | |
52 | ? bandwidth | |
53 | : EIGRP_BANDWIDTH_MAX; | |
54 | } | |
55 | ||
56 | return bandwidth; | |
57 | } | |
58 | ||
59 | eigrp_scaled_t eigrp_delay_to_scaled(eigrp_delay_t delay) | |
60 | { | |
61 | delay = delay ? delay : EIGRP_DELAY_MIN; | |
62 | return delay * EIGRP_CLASSIC_SCALER; | |
63 | } | |
64 | ||
65 | eigrp_delay_t eigrp_scaled_to_delay(eigrp_scaled_t scaled) | |
66 | { | |
67 | scaled = scaled / EIGRP_CLASSIC_SCALER; | |
68 | scaled = scaled ? scaled : EIGRP_DELAY_MIN; | |
69 | ||
70 | return scaled; | |
71 | } | |
72 | ||
73 | eigrp_metric_t eigrp_calculate_metrics(struct eigrp *eigrp, | |
74 | struct eigrp_metrics metric) | |
75 | { | |
76 | eigrp_metric_t composite = 0; | |
77 | ||
78 | if (metric.delay == EIGRP_MAX_METRIC) | |
79 | return EIGRP_METRIC_MAX; | |
80 | ||
81 | /* | |
82 | * EIGRP Composite = | |
83 | * {K1*BW+[(K2*BW)/(256-load)]+(K3*delay)}*{K5/(reliability+K4)} | |
84 | */ | |
85 | ||
86 | if (eigrp->k_values[0]) | |
87 | composite += (eigrp->k_values[0] * metric.bandwidth); | |
88 | if (eigrp->k_values[1]) | |
89 | composite += ((eigrp->k_values[1] * metric.bandwidth) | |
90 | / (256 - metric.load)); | |
91 | if (eigrp->k_values[2]) | |
92 | composite += (eigrp->k_values[2] * metric.delay); | |
93 | if (eigrp->k_values[3] && !eigrp->k_values[4]) | |
94 | composite *= eigrp->k_values[3]; | |
95 | if (!eigrp->k_values[3] && eigrp->k_values[4]) | |
96 | composite *= (eigrp->k_values[4] / metric.reliability); | |
97 | if (eigrp->k_values[3] && eigrp->k_values[4]) | |
98 | composite *= ((eigrp->k_values[4] / metric.reliability) | |
99 | + eigrp->k_values[3]); | |
100 | ||
101 | composite = | |
102 | (composite <= EIGRP_METRIC_MAX) ? composite : EIGRP_METRIC_MAX; | |
103 | ||
104 | return composite; | |
105 | } | |
106 | ||
107 | eigrp_metric_t | |
108 | eigrp_calculate_total_metrics(struct eigrp *eigrp, | |
109 | struct eigrp_route_descriptor *entry) | |
110 | { | |
111 | struct eigrp_interface *ei = entry->ei; | |
112 | eigrp_delay_t temp_delay; | |
113 | eigrp_bandwidth_t bw; | |
114 | ||
115 | entry->total_metric = entry->reported_metric; | |
116 | temp_delay = entry->total_metric.delay | |
117 | + eigrp_delay_to_scaled(ei->params.delay); | |
118 | ||
119 | entry->total_metric.delay = temp_delay > EIGRP_METRIC_MAX_CLASSIC | |
120 | ? EIGRP_METRIC_MAX_CLASSIC | |
121 | : temp_delay; | |
122 | ||
123 | bw = eigrp_bandwidth_to_scaled(ei->params.bandwidth); | |
124 | entry->total_metric.bandwidth = entry->total_metric.bandwidth > bw | |
125 | ? bw | |
126 | : entry->total_metric.bandwidth; | |
127 | ||
128 | return eigrp_calculate_metrics(eigrp, entry->total_metric); | |
129 | } | |
130 | ||
131 | bool eigrp_metrics_is_same(struct eigrp_metrics metric1, | |
132 | struct eigrp_metrics metric2) | |
133 | { | |
134 | if ((metric1.bandwidth == metric2.bandwidth) | |
135 | && (metric1.delay == metric2.delay) | |
136 | && (metric1.hop_count == metric2.hop_count) | |
137 | && (metric1.load == metric2.load) | |
138 | && (metric1.reliability == metric2.reliability) | |
139 | && (metric1.mtu[0] == metric2.mtu[0]) | |
140 | && (metric1.mtu[1] == metric2.mtu[1]) | |
141 | && (metric1.mtu[2] == metric2.mtu[2])) { | |
142 | return true; | |
143 | } | |
144 | ||
145 | return false; /* if different */ | |
146 | } |