From 41ecaedb0df0e4a66237facea86fcaf3f440a4c6 Mon Sep 17 00:00:00 2001
From: tamilmani1989 <tamilmani1989@gmail.com>
Date: Wed, 16 May 2018 17:02:09 -0700
Subject: [PATCH] Generate VethName based on podname and namespace in CNI
 (#143)

* Generate vethname based on podname and namespace
---
 cni/network/network.go    | 21 +++++++++++++++++++--
 network/api.go            |  2 ++
 network/endpoint_linux.go | 29 ++++++++++++++++++++++++-----
 3 files changed, 45 insertions(+), 7 deletions(-)

diff --git a/cni/network/network.go b/cni/network/network.go
index 7b1b570973..185e2d4def 100644
--- a/cni/network/network.go
+++ b/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)
diff --git a/network/api.go b/network/api.go
index 4b6b93ba81..9ce77c4dde 100644
--- a/network/api.go
+++ b/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"
 )
diff --git a/network/endpoint_linux.go b/network/endpoint_linux.go
index 0019c370cd..a33c5741cf 100644
--- a/network/endpoint_linux.go
+++ b/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)