go实现路由表操作

最新推荐文章于 2022-04-11 21:00:47 发布

原创最新推荐文章于 2022-04-11 21:00:47 发布 · 2.4k 阅读

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//源代码
package comrouting

import (
    "fmt"
    "strconv"
    "strings"
)

type CRoute_S struct {
    routeTable map[int]map[int]bool
}

func CreateCRouter() *CRoute_S {
    var route CRoute_S
    route.routeTable = make(map[int]map[int]bool)
    var maskLen int = 0
    for maskLen = 0; maskLen <= 32; maskLen++ {
        route.routeTable[maskLen] = make(map[int]bool)
    }
    return &route
}

func AddCRouteItem(cr *CRoute_S, prefix string, maskLen int) bool {
    if nil == cr || nil == cr.routeTable {
        return false
    }
    rtVal := ipStr2Val(prefix)
    if 0 > rtVal {
        return false
    }
    if maskLen < 0 {
        maskLen = 0
    } else if maskLen > 32 {
        maskLen = 32
    }
    rtVal = ipValMasked(rtVal, maskLen)
    cr.routeTable[maskLen][rtVal] = true
    return true
}

func DelCRouteItem(cr *CRoute_S, prefix string, maskLen int) bool {
    if nil == cr || nil == cr.routeTable {
        return false
    }
    rtVal := ipStr2Val(prefix)
    if 0 > rtVal {
        return false
    }
    if maskLen < 0 {
        maskLen = 0
    } else if maskLen > 32 {
        maskLen = 32
    }
    rtVal = ipValMasked(rtVal, maskLen)
    if _, bExist := cr.routeTable[maskLen][rtVal]; false == bExist {
        return true
    }
    delete(cr.routeTable[maskLen], rtVal)
    return true
}

func SearchCRoute(cr *CRoute_S, ip string) bool {
    if nil == cr || nil == cr.routeTable {
        return false
    }
    rtVal := ipStr2Val(ip)
    if 0 > rtVal {
        return false
    }
    var maskLen int = 0
    for maskLen = 32; maskLen >= 0; maskLen-- {
        tmpVal := ipValMasked(rtVal, maskLen)
        if _, bExist := cr.routeTable[maskLen][tmpVal]; bExist {
            fmt.Printf("SearchCRoute ip=%s match Item %s\n", ip, ipVal2Str(tmpVal))
            return true
        }
    }
    fmt.Printf("SearchCRoute ip=%s match Item fail\n", ip)
    return false
}

func PrintCRoute(cr *CRoute_S) {
    if nil == cr || nil == cr.routeTable {
        return
    }
    var maskLen int = 0
    for maskLen = 32; maskLen >= 0; maskLen-- {
        if 0 == len(cr.routeTable[maskLen]) {
            continue
        }
        fmt.Printf("maskLen=%d List As:\n", maskLen)
        itemSeq := 1
        for ipVal, _ := range cr.routeTable[maskLen] {
            fmt.Printf("%d: %s\n", itemSeq, ipVal2Str(ipVal))
            itemSeq++
        }
    }
}

func ipStr2Val(ip string) int {
    segs := strings.Split(strings.TrimSpace(ip), ".")
    if 4 != len(segs) {
        return -1
    }

    ret := make([]int, 0)
    for _, segx := range segs {
        val, err := strconv.Atoi(segx)
        if nil != err {
            return -1
        }
        ret = append(ret, val)
    }
    rtVal := ret[0]<<24 + ret[1]<<16 + ret[2]<<8 + ret[3]
    return rtVal
}

func ipVal2Str(ipVal int) string {
    s1 := (ipVal & 0xff000000) >> 24
    s2 := (ipVal & 0xff0000) >> 16
    s3 := (ipVal & 0xff00) >> 8
    s4 := (ipVal & 0xff)
    return fmt.Sprintf("%d.%d.%d.%d", s1, s2, s3, s4)
}

func ipValMasked(ipVal int, maskLen int) int {
    rtVal := (ipVal >> uint(32-maskLen)) & 0xffffffff
    rtVal = rtVal << uint(32-maskLen)
    return rtVal
}

//测试代码
package main

import (
    "common/comrouting"
    "fmt"
)

func main() {
    router := comrouting.CreateCRouter()
    comrouting.AddCRouteItem(router, "192.168.0.0", 16)
    comrouting.AddCRouteItem(router, "192.168.1.0", 24)
    comrouting.PrintCRoute(router)
    ret := comrouting.SearchCRoute(router, "192.168.1.0")
    fmt.Printf("ret=%v\n\n", ret)

    comrouting.DelCRouteItem(router, "192.168.1.0", 24)
    comrouting.PrintCRoute(router)
    ret = comrouting.SearchCRoute(router, "192.168.1.0")
    fmt.Printf("ret=%v\n", ret)
}