4677d920c0
- most functions and vars now start with a capital letter: needed to access them outside the package that declares them - updated README.md - very minor changes in MAKEFILE Type: test Change-Id: I4b5a194f08f09d59e372e57da6451fbb5a1de4da Signed-off-by: Adrian Villin <avillin@cisco.com>
99 lines
2.5 KiB
Go
99 lines
2.5 KiB
Go
package hst
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import (
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"errors"
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"fmt"
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"os"
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"strings"
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"github.com/edwarnicke/exechelper"
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)
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type AddressCounter = int
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type Ip4AddressAllocator struct {
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networks map[int]AddressCounter
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chosenOctet int
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assignedIps []string
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}
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func (a *Ip4AddressAllocator) AddNetwork(networkNumber int) {
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a.networks[networkNumber] = 1
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}
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func (a *Ip4AddressAllocator) NewIp4InterfaceAddress(inputNetworkNumber ...int) (string, error) {
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var networkNumber int = 0
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if len(inputNetworkNumber) > 0 {
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networkNumber = inputNetworkNumber[0]
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}
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if _, ok := a.networks[networkNumber]; !ok {
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a.AddNetwork(networkNumber)
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}
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numberOfAddresses := a.networks[networkNumber]
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if numberOfAddresses == 254 {
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return "", fmt.Errorf("no available IPv4 addresses")
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}
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address, err := a.createIpAddress(networkNumber, numberOfAddresses)
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a.networks[networkNumber] = numberOfAddresses + 1
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return address + "/24", err
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}
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// Creates a file every time an IP is assigned: used to keep track of addresses in use.
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// If an address is not in use, 'counter' is then copied to 'chosenOctet' and it is used for the remaining tests.
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// Also checks host IP addresses.
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func (a *Ip4AddressAllocator) createIpAddress(networkNumber int, numberOfAddresses int) (string, error) {
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hostIps, _ := exechelper.CombinedOutput("ip a")
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counter := 10
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var address string
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for {
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if a.chosenOctet != 0 {
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address = fmt.Sprintf("10.%v.%v.%v", a.chosenOctet, networkNumber, numberOfAddresses)
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file, err := os.Create(address)
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if err != nil {
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return "", errors.New("unable to create file: " + fmt.Sprint(err))
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}
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file.Close()
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break
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} else {
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address = fmt.Sprintf("10.%v.%v.%v", counter, networkNumber, numberOfAddresses)
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_, err := os.Stat(address)
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if err == nil || strings.Contains(string(hostIps), address) {
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counter++
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} else if os.IsNotExist(err) {
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file, err := os.Create(address)
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if err != nil {
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return "", errors.New("unable to create file: " + fmt.Sprint(err))
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}
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file.Close()
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a.chosenOctet = counter
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break
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} else {
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return "", errors.New("an error occurred while checking if a file exists: " + fmt.Sprint(err))
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}
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}
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}
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a.assignedIps = append(a.assignedIps, address)
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return address, nil
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}
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func (a *Ip4AddressAllocator) DeleteIpAddresses() {
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for ip := range a.assignedIps {
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os.Remove(a.assignedIps[ip])
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}
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}
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func NewIp4AddressAllocator() *Ip4AddressAllocator {
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var ip4AddrAllocator = new(Ip4AddressAllocator)
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ip4AddrAllocator.networks = make(map[int]AddressCounter)
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ip4AddrAllocator.AddNetwork(0)
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return ip4AddrAllocator
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}
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