mirror of
https://github.com/openziti/ziti.git
synced 2026-09-11 21:38:58 +00:00
Paul Lorenz
106 lines
2.3 KiB
Go
106 lines
2.3 KiB
Go
/*
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Copyright NetFoundry, Inc.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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https://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package network
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import (
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"errors"
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"math"
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)
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func (network *Network) shortestPath(srcR *Router, dstR *Router) ([]*Router, error) {
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if srcR == nil || dstR == nil {
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return nil, errors.New("not routable (!srcR||!dstR)")
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}
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if srcR == dstR {
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return []*Router{srcR}, nil
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}
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dist := make(map[*Router]int64)
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prev := make(map[*Router]*Router)
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unvisited := make(map[*Router]bool)
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for _, r := range network.Routers.allConnected() {
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dist[r] = math.MaxInt32
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unvisited[r] = true
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}
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dist[srcR] = 0
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for len(unvisited) > 0 {
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u := minCost(unvisited, dist)
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delete(unvisited, u)
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neighbors := network.linkController.connectedNeighborsOfRouter(u)
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for _, r := range neighbors {
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if _, found := unvisited[r]; found {
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cost := int64(r.CostFactor)
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if l, found := network.linkController.leastExpensiveLink(r, u); found {
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cost += l.SrcLatency
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cost += l.DstLatency
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}
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alt := dist[u] + cost
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if alt < dist[r] {
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dist[r] = alt
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prev[r] = u
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}
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}
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}
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}
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/*
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* dist: (r2->r1->r0)
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* r0 = 2 <- r1
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* r1 = 1 <- r2
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* r2 = 0 <- nil
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*/
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routerPath := make([]*Router, 0)
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p := prev[dstR]
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for p != nil {
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routerPath = append([]*Router{p}, routerPath...)
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p = prev[p]
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}
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routerPath = append(routerPath, dstR)
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if routerPath[0] != srcR {
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return nil, errors.New("not routable (~srcR)")
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}
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if routerPath[len(routerPath)-1] != dstR {
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return nil, errors.New("not routable (~dstR)")
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}
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return routerPath, nil
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}
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func minCost(q map[*Router]bool, dist map[*Router]int64) *Router {
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if dist == nil || len(dist) < 1 {
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return nil
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}
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min := int64(math.MaxInt64)
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var selected *Router
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for r := range q {
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d := dist[r]
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if d <= min {
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selected = r
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min = d
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}
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}
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return selected
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}
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