Introduce proxy for VPP

- proxy server defines RPC service for proxying binapi/stats to VPP
- use cmd/vpp-proxy for proxy server/client

Change-Id: I6e698e166ecf6db7109ae5adf8a93f308d3f3f2a
Signed-off-by: Ondrej Fabry <ofabry@cisco.com>

3 files changed, 389 insertions, 0 deletions

diff --git a/proxy/client.go b/proxy/client.go
new file mode 100644
index 0000000..72ee9e9
--- /dev/null
+++ b/proxy/client.go
@@ -0,0 +1,178 @@
+package proxy
+
+import (
+	"fmt"
+	"log"
+	"net/rpc"
+	"reflect"
+	"time"
+
+	"git.fd.io/govpp.git/api"
+)
+
+type Client struct {
+	serverAddr string
+	rpc        *rpc.Client
+}
+
+// Connect dials remote proxy server on given address and
+// returns new client if successful.
+func Connect(addr string) (*Client, error) {
+	client, err := rpc.DialHTTP("tcp", addr)
+	if err != nil {
+		log.Fatal("Connection error: ", err)
+	}
+	c := &Client{
+		serverAddr: addr,
+		rpc:        client,
+	}
+	return c, nil
+}
+
+// NewStatsClient returns new StatsClient which implements api.StatsProvider.
+func (c *Client) NewStatsClient() (*StatsClient, error) {
+	stats := &StatsClient{
+		rpc: c.rpc,
+	}
+	return stats, nil
+}
+
+// NewBinapiClient returns new BinapiClient which implements api.Channel.
+func (c *Client) NewBinapiClient() (*BinapiClient, error) {
+	binapi := &BinapiClient{
+		rpc: c.rpc,
+	}
+	return binapi, nil
+}
+
+type StatsClient struct {
+	rpc *rpc.Client
+}
+
+func (s *StatsClient) GetSystemStats(sysStats *api.SystemStats) error {
+	req := StatsRequest{StatsType: "system"}
+	resp := StatsResponse{SysStats: sysStats}
+	return s.rpc.Call("StatsRPC.GetStats", req, &resp)
+}
+
+func (s *StatsClient) GetNodeStats(nodeStats *api.NodeStats) error {
+	req := StatsRequest{StatsType: "node"}
+	resp := StatsResponse{NodeStats: nodeStats}
+	return s.rpc.Call("StatsRPC.GetStats", req, &resp)
+}
+
+func (s *StatsClient) GetInterfaceStats(ifaceStats *api.InterfaceStats) error {
+	req := StatsRequest{StatsType: "interface"}
+	resp := StatsResponse{IfaceStats: ifaceStats}
+	return s.rpc.Call("StatsRPC.GetStats", req, &resp)
+}
+
+func (s *StatsClient) GetErrorStats(errStats *api.ErrorStats) error {
+	req := StatsRequest{StatsType: "error"}
+	resp := StatsResponse{ErrStats: errStats}
+	return s.rpc.Call("StatsRPC.GetStats", req, &resp)
+}
+
+func (s *StatsClient) GetBufferStats(bufStats *api.BufferStats) error {
+	req := StatsRequest{StatsType: "buffer"}
+	resp := StatsResponse{BufStats: bufStats}
+	return s.rpc.Call("StatsRPC.GetStats", req, &resp)
+}
+
+type BinapiClient struct {
+	rpc *rpc.Client
+}
+
+func (b *BinapiClient) SendRequest(msg api.Message) api.RequestCtx {
+	req := &requestCtx{
+		rpc: b.rpc,
+		req: msg,
+	}
+	log.Printf("SendRequest: %T %+v", msg, msg)
+	return req
+}
+
+type requestCtx struct {
+	rpc *rpc.Client
+	req api.Message
+}
+
+func (r *requestCtx) ReceiveReply(msg api.Message) error {
+	req := BinapiRequest{
+		Msg:      r.req,
+		ReplyMsg: msg,
+	}
+	resp := BinapiResponse{}
+
+	err := r.rpc.Call("BinapiRPC.Invoke", req, &resp)
+	if err != nil {
+		return fmt.Errorf("RPC call failed: %v", err)
+	}
+
+	// we set the value of msg to the value from response
+	reflect.ValueOf(msg).Elem().Set(reflect.ValueOf(resp.Msg).Elem())
+
+	return nil
+}
+
+func (b *BinapiClient) SendMultiRequest(msg api.Message) api.MultiRequestCtx {
+	req := &multiRequestCtx{
+		rpc: b.rpc,
+		req: msg,
+	}
+	log.Printf("SendMultiRequest: %T %+v", msg, msg)
+	return req
+}
+
+type multiRequestCtx struct {
+	rpc *rpc.Client
+	req api.Message
+
+	index   int
+	replies []api.Message
+}
+
+func (r *multiRequestCtx) ReceiveReply(msg api.Message) (stop bool, err error) {
+	// we call Invoke only on first ReceiveReply
+	if r.index == 0 {
+		req := BinapiRequest{
+			Msg:      r.req,
+			ReplyMsg: msg,
+			IsMulti:  true,
+		}
+		resp := BinapiResponse{}
+
+		err := r.rpc.Call("BinapiRPC.Invoke", req, &resp)
+		if err != nil {
+			return false, fmt.Errorf("RPC call failed: %v", err)
+		}
+
+		r.replies = resp.Msgs
+	}
+
+	if r.index >= len(r.replies) {
+		return true, nil
+	}
+
+	// we set the value of msg to the value from response
+	reflect.ValueOf(msg).Elem().Set(reflect.ValueOf(r.replies[r.index]).Elem())
+	r.index++
+
+	return false, nil
+}
+
+func (b *BinapiClient) SubscribeNotification(notifChan chan api.Message, event api.Message) (api.SubscriptionCtx, error) {
+	panic("implement me")
+}
+
+func (b *BinapiClient) SetReplyTimeout(timeout time.Duration) {
+	panic("implement me")
+}
+
+func (b *BinapiClient) CheckCompatiblity(msgs ...api.Message) error {
+	return nil // TODO: proxy this
+}
+
+func (b *BinapiClient) Close() {
+	b.rpc.Close()
+}
diff --git a/proxy/proxy.go b/proxy/proxy.go
new file mode 100644
index 0000000..1f8f824
--- /dev/null
+++ b/proxy/proxy.go
@@ -0,0 +1,102 @@
+//  Copyright (c) 2019 Cisco and/or its affiliates.
+//
+//  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.
+
+package proxy
+
+import (
+	"log"
+	"net"
+	"net/http"
+	"net/rpc"
+
+	"git.fd.io/govpp.git/adapter"
+	"git.fd.io/govpp.git/core"
+)
+
+// Server defines a proxy server that serves client requests to stats and binapi.
+type Server struct {
+	rpc *rpc.Server
+
+	statsConn  *core.StatsConnection
+	binapiConn *core.Connection
+}
+
+func NewServer() *Server {
+	return &Server{
+		rpc: rpc.NewServer(),
+	}
+}
+
+func (p *Server) ConnectStats(stats adapter.StatsAPI) error {
+	var err error
+	p.statsConn, err = core.ConnectStats(stats)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func (p *Server) DisconnectStats() {
+	if p.statsConn != nil {
+		p.statsConn.Disconnect()
+	}
+}
+
+func (p *Server) ConnectBinapi(binapi adapter.VppAPI) error {
+	var err error
+	p.binapiConn, err = core.Connect(binapi)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func (p *Server) DisconnectBinapi() {
+	if p.binapiConn != nil {
+		p.binapiConn.Disconnect()
+	}
+}
+
+func (p *Server) ListenAndServe(addr string) {
+	if p.statsConn != nil {
+		statsRPC := NewStatsRPC(p.statsConn)
+		if err := p.rpc.Register(statsRPC); err != nil {
+			panic(err)
+		}
+	}
+	if p.binapiConn != nil {
+		ch, err := p.binapiConn.NewAPIChannel()
+		if err != nil {
+			panic(err)
+		}
+		binapiRPC := NewBinapiRPC(ch)
+		if err := p.rpc.Register(binapiRPC); err != nil {
+			panic(err)
+		}
+	}
+
+	p.rpc.HandleHTTP(rpc.DefaultRPCPath, rpc.DefaultDebugPath)
+
+	l, e := net.Listen("tcp", addr)
+	if e != nil {
+		log.Fatal("listen error:", e)
+	}
+	defer l.Close()
+
+	log.Printf("proxy serving on: %v", addr)
+
+	if err := http.Serve(l, nil); err != nil {
+		log.Fatalln(err)
+	}
+}
diff --git a/proxy/server.go b/proxy/server.go
new file mode 100644
index 0000000..df62356
--- /dev/null
+++ b/proxy/server.go
@@ -0,0 +1,109 @@
+package proxy
+
+import (
+	"fmt"
+	"log"
+	"reflect"
+
+	"git.fd.io/govpp.git/api"
+)
+
+type StatsRequest struct {
+	StatsType string
+}
+
+type StatsResponse struct {
+	SysStats   *api.SystemStats
+	NodeStats  *api.NodeStats
+	IfaceStats *api.InterfaceStats
+	ErrStats   *api.ErrorStats
+	BufStats   *api.BufferStats
+}
+
+// StatsRPC is a RPC server for proxying client request to api.StatsProvider.
+type StatsRPC struct {
+	stats api.StatsProvider
+}
+
+// NewStatsRPC returns new StatsRPC to be used as RPC server
+// proxying request to given api.StatsProvider.
+func NewStatsRPC(stats api.StatsProvider) *StatsRPC {
+	return &StatsRPC{stats: stats}
+}
+
+func (s *StatsRPC) GetStats(req StatsRequest, resp *StatsResponse) error {
+	log.Printf("StatsRPC.GetStats - REQ: %+v", req)
+
+	switch req.StatsType {
+	case "system":
+		resp.SysStats = new(api.SystemStats)
+		return s.stats.GetSystemStats(resp.SysStats)
+	case "node":
+		resp.NodeStats = new(api.NodeStats)
+		return s.stats.GetNodeStats(resp.NodeStats)
+	case "interface":
+		resp.IfaceStats = new(api.InterfaceStats)
+		return s.stats.GetInterfaceStats(resp.IfaceStats)
+	case "error":
+		resp.ErrStats = new(api.ErrorStats)
+		return s.stats.GetErrorStats(resp.ErrStats)
+	case "buffer":
+		resp.BufStats = new(api.BufferStats)
+		return s.stats.GetBufferStats(resp.BufStats)
+	default:
+		return fmt.Errorf("unknown stats type: %s", req.StatsType)
+	}
+}
+
+type BinapiRequest struct {
+	Msg      api.Message
+	IsMulti  bool
+	ReplyMsg api.Message
+}
+
+type BinapiResponse struct {
+	Msg  api.Message
+	Msgs []api.Message
+}
+
+// BinapiRPC is a RPC server for proxying client request to api.Channel.
+type BinapiRPC struct {
+	binapi api.Channel
+}
+
+// NewBinapiRPC returns new BinapiRPC to be used as RPC server
+// proxying request to given api.Channel.
+func NewBinapiRPC(binapi api.Channel) *BinapiRPC {
+	return &BinapiRPC{binapi: binapi}
+}
+
+func (s *BinapiRPC) Invoke(req BinapiRequest, resp *BinapiResponse) error {
+	log.Printf("BinapiRPC.Invoke - REQ: %#v", req)
+
+	if req.IsMulti {
+		multi := s.binapi.SendMultiRequest(req.Msg)
+		for {
+			// create new message in response of type ReplyMsg
+			msg := reflect.New(reflect.TypeOf(req.ReplyMsg).Elem()).Interface().(api.Message)
+
+			stop, err := multi.ReceiveReply(msg)
+			if err != nil {
+				return err
+			} else if stop {
+				break
+			}
+
+			resp.Msgs = append(resp.Msgs, msg)
+		}
+	} else {
+		// create new message in response of type ReplyMsg
+		resp.Msg = reflect.New(reflect.TypeOf(req.ReplyMsg).Elem()).Interface().(api.Message)
+
+		err := s.binapi.SendRequest(req.Msg).ReceiveReply(resp.Msg)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}