Generate VethName based on podname and namespace in CNI (Azure#143)

* Generate vethname based on podname and namespace

Author: tamilmani1989

cni/network/network.go

@@ -4,6 +4,7 @@
 package network
 
 import (
+"fmt"
 "net"
 "strings"
 
@@ -162,10 +163,23 @@ func (plugin *netPlugin) Add(args *cniSkel.CmdArgs) error {
 
 // Parse Pod arguments.
 podCfg, err := cni.ParseCniArgs(args.Args)
+if err != nil {
+log.Printf("Error while parsing CNI Args %v", err)
+return err
+}
+
 k8sNamespace := string(podCfg.K8S_POD_NAMESPACE)
 if len(k8sNamespace) == 0 {
-err = plugin.Errorf("No k8s pod namespace provided.")
-return err
+errMsg := "Pod Namespace not specified in CNI Args"
+log.Printf(errMsg)
+return plugin.Errorf(errMsg)
+}
+
+k8sPodName := string(podCfg.K8S_POD_NAME)
+if len(k8sPodName) == 0 {
+errMsg := "Pod Name not specified in CNI Args"
+log.Printf(errMsg)
+return plugin.Errorf(errMsg)
 }
 
 // Parse network configuration from stdin.
@@ -334,6 +348,9 @@ func (plugin *netPlugin) Add(args *cniSkel.CmdArgs) error {
 epInfo.Routes = append(epInfo.Routes, network.RouteInfo{Dst: route.Dst, Gw: route.GW})
 }
 
+epInfo.Data = make(map[string]interface{})
+epInfo.Data[network.OptVethName] = fmt.Sprintf("%s.%s", k8sNamespace, k8sPodName)
+
 // Create the endpoint.
 log.Printf("[cni-net] Creating endpoint %v.", epInfo.Id)
 err = plugin.nm.CreateEndpoint(networkId, epInfo)

network/api.go

@@ -17,4 +17,6 @@ var (
 errEndpointNotFound = fmt.Errorf("Endpoint not found")
 errEndpointInUse = fmt.Errorf("Endpoint is already joined to a sandbox")
 errEndpointNotInUse = fmt.Errorf("Endpoint is not joined to a sandbox")
+
+OptVethName = "vethname"
 )

network/endpoint_linux.go

@@ -6,6 +6,8 @@
 package network
 
 import (
+"crypto/sha1"
+"encoding/hex"
 "fmt"
 "net"
 
@@ -19,28 +21,45 @@ const (
 commonInterfacePrefix = "az"
 
 // Prefix for host virtual network interface names.
-hostVEthInterfacePrefix = commonInterfacePrefix + "veth"
+hostVEthInterfacePrefix = commonInterfacePrefix + "v"
 
 // Prefix for container network interface names.
 containerInterfacePrefix = "eth"
 )
 
+func generateVethName(key string) string {
+h := sha1.New()
+h.Write([]byte(key))
+return hex.EncodeToString(h.Sum(nil))[:11]
+}
+
 // newEndpointImpl creates a new endpoint in the network.
 func (nw *network) newEndpointImpl(epInfo *EndpointInfo) (*endpoint, error) {
 var containerIf *net.Interface
 var ns *Namespace
 var ep *endpoint
 var err error
+var hostIfName string
+var contIfName string
 
 if nw.Endpoints[epInfo.Id] != nil {
-log.Printf("[net] Endpoint alreday exists.")
+log.Printf("[net] Endpoint alreday exists.")
 err = errEndpointExists
 return nil, err
 }
 
-// Create a veth pair.
-hostIfName := fmt.Sprintf("%s%s", hostVEthInterfacePrefix, epInfo.Id[:7])
-contIfName := fmt.Sprintf("%s%s-2", hostVEthInterfacePrefix, epInfo.Id[:7])
+if _, ok := epInfo.Data[OptVethName]; ok {
+log.Printf("Generate veth name based on the key provided")
+key := epInfo.Data[OptVethName].(string)
+vethname := generateVethName(key)
+hostIfName = fmt.Sprintf("%s%s", hostVEthInterfacePrefix, vethname)
+contIfName = fmt.Sprintf("%s%s2", hostVEthInterfacePrefix, vethname)
+} else {
+// Create a veth pair.
+log.Printf("Generate veth name based on endpoint id")
+hostIfName = fmt.Sprintf("%s%s", hostVEthInterfacePrefix, epInfo.Id[:7])
+contIfName = fmt.Sprintf("%s%s-2", hostVEthInterfacePrefix, epInfo.Id[:7])
+}
 
 log.Printf("[net] Creating veth pair %v %v.", hostIfName, contIfName)