Merge pull request #7943 from baude/issue7807

prevent unpredictable results with network create|remove

1 files changed, 63 insertions, 0 deletions

diff --git a/libpod/network/devices.go b/libpod/network/devices.go
new file mode 100644
index 000000000..a5d23fae4
--- /dev/null
+++ b/libpod/network/devices.go
@@ -0,0 +1,63 @@
+package network
+
+import (
+	"fmt"
+	"os/exec"
+
+	"github.com/containers/common/pkg/config"
+	"github.com/containers/podman/v2/pkg/util"
+	"github.com/containers/podman/v2/utils"
+	"github.com/sirupsen/logrus"
+)
+
+// GetFreeDeviceName returns a device name that is unused; used when no network
+// name is provided by user
+func GetFreeDeviceName(config *config.Config) (string, error) {
+	var (
+		deviceNum  uint
+		deviceName string
+	)
+	networkNames, err := GetNetworkNamesFromFileSystem(config)
+	if err != nil {
+		return "", err
+	}
+	liveNetworksNames, err := GetLiveNetworkNames()
+	if err != nil {
+		return "", err
+	}
+	bridgeNames, err := GetBridgeNamesFromFileSystem(config)
+	if err != nil {
+		return "", err
+	}
+	for {
+		deviceName = fmt.Sprintf("%s%d", CNIDeviceName, deviceNum)
+		logrus.Debugf("checking if device name %q exists in other cni networks", deviceName)
+		if util.StringInSlice(deviceName, networkNames) {
+			deviceNum++
+			continue
+		}
+		logrus.Debugf("checking if device name %q exists in live networks", deviceName)
+		if util.StringInSlice(deviceName, liveNetworksNames) {
+			deviceNum++
+			continue
+		}
+		logrus.Debugf("checking if device name %q already exists as a bridge name ", deviceName)
+		if !util.StringInSlice(deviceName, bridgeNames) {
+			break
+		}
+		deviceNum++
+	}
+	return deviceName, nil
+}
+
+// RemoveInterface removes an interface by the given name
+func RemoveInterface(interfaceName string) error {
+	// Make sure we have the ip command on the system
+	ipPath, err := exec.LookPath("ip")
+	if err != nil {
+		return err
+	}
+	// Delete the network interface
+	_, err = utils.ExecCmd(ipPath, []string{"link", "del", interfaceName}...)
+	return err
+}