[VOL-785,VOL-786,VOL-1315,VOL-1316]
Initial commit of the affinity router's data plane

Change-Id: Iccc93b5526d5d2468b33eff7d8847e22fb88ef2d
diff --git a/afrouter/afrouter/round-robin-router.go b/afrouter/afrouter/round-robin-router.go
new file mode 100644
index 0000000..2ab8421
--- /dev/null
+++ b/afrouter/afrouter/round-robin-router.go
@@ -0,0 +1,131 @@
+/*
+ * Copyright 2018-present Open Networking Foundation
+
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+
+ * http://www.apache.org/licenses/LICENSE-2.0
+
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+// gRPC affinity router with active/active backends
+
+package afrouter
+
+import (
+	"fmt"
+	"errors"
+	"google.golang.org/grpc"
+	"github.com/opencord/voltha-go/common/log"
+)
+
+type RoundRobinRouter struct {
+	name string
+	routerType int // TODO: Likely not needed.
+	grpcService string
+	bkndClstr *backendCluster
+	curBknd **backend
+}
+
+func NewRoundRobinRouter(rconf *RouterConfig, config *RouteConfig) (Router, error) {
+	var err error = nil
+	var rtrn_err bool = false
+	// Validate the configuration
+
+	log.Debug("Creating a new round robin router")
+	// A name must exist
+	if config.Name == "" {
+		log.Error("A router 'name' must be specified")
+		rtrn_err = true
+	}
+
+	if rconf.ProtoPackage == "" {
+		log.Error("A 'package' must be specified")
+		rtrn_err = true
+	}
+
+	if rconf.ProtoService == "" {
+		log.Error("A 'service' must be specified")
+		rtrn_err = true
+	}
+
+	var bptr *backend
+	bptr = nil
+	rr := RoundRobinRouter{
+		name:config.Name,
+		grpcService:rconf.ProtoService,
+		curBknd:&bptr,
+	}
+
+	// This has already been validated bfore this function
+	// is called so just use it.
+	for idx := range(rTypeNames) {
+		if config.Type == rTypeNames[idx] {
+			rr.routerType = idx
+			break
+		}
+	}
+
+	// Create the backend cluster or link to an existing one 
+	ok := true
+	if rr.bkndClstr, ok = bClusters[config.backendCluster.Name]; ok == false {
+		if rr.bkndClstr, err = NewBackendCluster(config.backendCluster); err != nil {
+			log.Errorf("Could not create a backend for router %s", config.Name)
+			rtrn_err = true
+		}
+	}
+
+	if rtrn_err {
+		return rr,errors.New(fmt.Sprintf("Failed to create a new router '%s'",rr.name))
+	}
+
+	return rr,nil
+}
+
+func (rr RoundRobinRouter) GetMetaKeyVal(serverStream grpc.ServerStream) (string,string,error) {
+	return "","",nil
+}
+
+func (rr RoundRobinRouter) BackendCluster(s string, mk string) (*backendCluster,error) {
+	return rr.bkndClstr, nil
+}
+
+func (rr RoundRobinRouter) Name() (string) {
+	return rr.name
+}
+
+func(rr RoundRobinRouter) Route(sel interface{}) (*backend) {
+	var err error
+	switch sl := sel.(type) {
+		case *nbFrame:
+			// Since this is a round robin router just get the next backend
+			if *rr.curBknd, err = rr.bkndClstr.nextBackend(*rr.curBknd,BE_SEQ_RR); err == nil {
+				return *rr.curBknd
+			} else {
+				sl.err = err
+				return nil
+			}
+		default:
+			log.Errorf("Internal: invalid data type in Route call %v", sel);
+			return nil
+	}
+	log.Errorf("Round robin error %v", err);
+	return nil
+}
+
+func (rr RoundRobinRouter) Service() (string) {
+	return rr.grpcService
+}
+
+func (rr RoundRobinRouter) FindBackendCluster(string) (*backendCluster) {
+	return rr.bkndClstr
+}
+
+func (rr RoundRobinRouter) ReplyHandler(sel interface{}) error { // This is a no-op
+	return nil
+}