1 files changed, 98 insertions, 0 deletions
diff --git a/extras/hs-test/address_allocator.go b/extras/hs-test/address_allocator.go
new file mode 100644
index 00000000000..e05ea76b9bb
--- /dev/null
+++ b/extras/hs-test/address_allocator.go
@@ -0,0 +1,98 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/edwarnicke/exechelper"
+)
+
+type AddressCounter = int
+
+type Ip4AddressAllocator struct {
+	networks    map[int]AddressCounter
+	chosenOctet int
+	assignedIps []string
+}
+
+func (a *Ip4AddressAllocator) AddNetwork(networkNumber int) {
+	a.networks[networkNumber] = 1
+}
+
+func (a *Ip4AddressAllocator) NewIp4InterfaceAddress(inputNetworkNumber ...int) (string, error) {
+	var networkNumber int = 0
+	if len(inputNetworkNumber) > 0 {
+		networkNumber = inputNetworkNumber[0]
+	}
+
+	if _, ok := a.networks[networkNumber]; !ok {
+		a.AddNetwork(networkNumber)
+	}
+
+	numberOfAddresses := a.networks[networkNumber]
+
+	if numberOfAddresses == 254 {
+		return "", fmt.Errorf("no available IPv4 addresses")
+	}
+
+	address, err := a.createIpAddress(networkNumber, numberOfAddresses)
+
+	a.networks[networkNumber] = numberOfAddresses + 1
+
+	return address + "/24", err
+}
+
+// Creates a file every time an IP is assigned: used to keep track of addresses in use.
+// If an address is not in use, 'counter' is then copied to 'chosenOctet' and it is used for the remaining tests.
+// Also checks host IP addresses.
+func (a *Ip4AddressAllocator) createIpAddress(networkNumber int, numberOfAddresses int) (string, error) {
+	hostIps, _ := exechelper.CombinedOutput("ip a")
+	counter := 10
+	var address string
+
+	for {
+		if a.chosenOctet != 0 {
+			address = fmt.Sprintf("10.%v.%v.%v", a.chosenOctet, networkNumber, numberOfAddresses)
+			file, err := os.Create(address)
+			if err != nil {
+				return "", errors.New("unable to create file: " + fmt.Sprint(err))
+			}
+			file.Close()
+			break
+		} else {
+			address = fmt.Sprintf("10.%v.%v.%v", counter, networkNumber, numberOfAddresses)
+			_, err := os.Stat(address)
+			if err == nil || strings.Contains(string(hostIps), address) {
+				counter++
+			} else if os.IsNotExist(err) {
+				file, err := os.Create(address)
+				if err != nil {
+					return "", errors.New("unable to create file: " + fmt.Sprint(err))
+				}
+				file.Close()
+				a.chosenOctet = counter
+				break
+			} else {
+				return "", errors.New("an error occurred while checking if a file exists: " + fmt.Sprint(err))
+			}
+		}
+	}
+
+	a.assignedIps = append(a.assignedIps, address)
+	return address, nil
+}
+
+func (a *Ip4AddressAllocator) deleteIpAddresses() {
+	for ip := range a.assignedIps {
+		os.Remove(a.assignedIps[ip])
+	}
+}
+
+func NewIp4AddressAllocator() *Ip4AddressAllocator {
+	var ip4AddrAllocator = new(Ip4AddressAllocator)
+	ip4AddrAllocator.networks = make(map[int]AddressCounter)
+	ip4AddrAllocator.AddNetwork(0)
+	return ip4AddrAllocator
+}