1 files changed, 213 insertions, 0 deletions
diff --git a/core/request_handler.go b/core/request_handler.go
new file mode 100644
index 0000000..f4f5e92
--- /dev/null
+++ b/core/request_handler.go
@@ -0,0 +1,213 @@
+// Copyright (c) 2017 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 core
+
+import (
+	"errors"
+	"fmt"
+	"sync/atomic"
+
+	logger "github.com/Sirupsen/logrus"
+
+	"git.fd.io/govpp.git/api"
+	"git.fd.io/govpp.git/core/bin_api/vpe"
+)
+
+// watchRequests watches for requests on the request API channel and forwards them as messages to VPP.
+func (c *Connection) watchRequests(ch *api.Channel, chMeta *channelMetadata) {
+	for {
+		select {
+		case req, ok := <-ch.ReqChan:
+			// new request on the request channel
+			if !ok {
+				// after closing the request channel, release API channel and return
+				c.releaseAPIChannel(ch, chMeta)
+				return
+			}
+			c.processRequest(ch, chMeta, req)
+
+		case req := <-ch.NotifSubsChan:
+			// new request on the notification subscribe channel
+			c.processNotifSubscribeRequest(ch, req)
+		}
+	}
+}
+
+// processRequest processes a single request received on the request channel.
+func (c *Connection) processRequest(ch *api.Channel, chMeta *channelMetadata, req *api.VppRequest) error {
+	// check whether we are connected to VPP
+	if atomic.LoadUint32(&c.connected) == 0 {
+		error := errors.New("not connected to VPP, ignoring the request")
+		log.Error(error)
+		sendReply(ch, &api.VppReply{Error: error})
+		return error
+	}
+
+	// retrieve message ID
+	msgID, err := c.GetMessageID(req.Message)
+	if err != nil {
+		error := fmt.Errorf("unable to retrieve message ID: %v", err)
+		log.WithFields(logger.Fields{
+			"msg_name": req.Message.GetMessageName(),
+			"msg_crc":  req.Message.GetCrcString(),
+		}).Error(err)
+		sendReply(ch, &api.VppReply{Error: error})
+		return error
+	}
+
+	// encode the message into binary
+	data, err := c.codec.EncodeMsg(req.Message, msgID)
+	if err != nil {
+		error := fmt.Errorf("unable to encode the messge: %v", err)
+		log.WithFields(logger.Fields{
+			"context": chMeta.id,
+			"msg_id":  msgID,
+		}).Error(error)
+		sendReply(ch, &api.VppReply{Error: error})
+		return error
+	}
+
+	// send the message
+	log.WithFields(logger.Fields{
+		"context":  chMeta.id,
+		"msg_id":   msgID,
+		"msg_size": len(data),
+	}).Debug("Sending a message to VPP.")
+
+	if req.Multipart {
+		// expect multipart response
+		atomic.StoreUint32(&chMeta.multipart, 1)
+	}
+
+	// send the request to VPP
+	c.vpp.SendMsg(chMeta.id, data)
+
+	if req.Multipart {
+		// send a control ping to determine end of the multipart response
+		ping := &vpe.ControlPing{}
+		pingData, _ := c.codec.EncodeMsg(ping, c.pingReqID)
+
+		log.WithFields(logger.Fields{
+			"context":  chMeta.id,
+			"msg_id":   c.pingReqID,
+			"msg_size": len(pingData),
+		}).Debug("Sending a control ping to VPP.")
+
+		c.vpp.SendMsg(chMeta.id, pingData)
+	}
+
+	return nil
+}
+
+// msgCallback is called whenever any binary API message comes from VPP.
+func msgCallback(context uint32, msgID uint16, data []byte) {
+	connLock.RLock()
+	defer connLock.RUnlock()
+
+	if conn == nil {
+		log.Warn("Already disconnected, ignoring the message.")
+		return
+	}
+
+	log.WithFields(logger.Fields{
+		"context":  context,
+		"msg_id":   msgID,
+		"msg_size": len(data),
+	}).Debug("Received a message from VPP.")
+
+	if context == 0 || conn.isNotificationMessage(msgID) {
+		// process the message as a notification
+		conn.sendNotifications(msgID, data)
+		return
+	}
+
+	// match ch according to the context
+	conn.channelsLock.RLock()
+	ch, ok := conn.channels[context]
+	conn.channelsLock.RUnlock()
+
+	if !ok {
+		log.WithFields(logger.Fields{
+			"context": context,
+			"msg_id":  msgID,
+		}).Error("Context ID not known, ignoring the message.")
+		return
+	}
+
+	chMeta := ch.Metadata().(*channelMetadata)
+	lastReplyReceived := false
+	// if this is a control ping reply and multipart request is being processed, treat this as a last part of the reply
+	if msgID == conn.pingReplyID && atomic.CompareAndSwapUint32(&chMeta.multipart, 1, 0) {
+		lastReplyReceived = true
+	}
+
+	// send the data to the channel
+	sendReply(ch, &api.VppReply{
+		MessageID:         msgID,
+		Data:              data,
+		LastReplyReceived: lastReplyReceived,
+	})
+}
+
+// sendReply sends the reply into the go channel, if it cannot be completed without blocking, otherwise
+// it logs the error and do not send the message.
+func sendReply(ch *api.Channel, reply *api.VppReply) {
+	select {
+	case ch.ReplyChan <- reply:
+		// reply sent successfully
+	default:
+		// unable to write into the channel without blocking
+		log.WithFields(logger.Fields{
+			"channel": ch,
+			"msg_id":  reply.MessageID,
+		}).Warn("Unable to send the reply, reciever end not ready.")
+	}
+}
+
+// GetMessageID returns message identifier of given API message.
+func (c *Connection) GetMessageID(msg api.Message) (uint16, error) {
+	if c == nil {
+		return 0, errors.New("nil connection passed in")
+	}
+	return c.messageNameToID(msg.GetMessageName(), msg.GetCrcString())
+}
+
+// messageNameToID returns message ID of a message identified by its name and CRC.
+func (c *Connection) messageNameToID(msgName string, msgCrc string) (uint16, error) {
+	// try to get the ID from the map
+	c.msgIDsLock.RLock()
+	id, ok := c.msgIDs[msgName+msgCrc]
+	c.msgIDsLock.RUnlock()
+	if ok {
+		return id, nil
+	}
+
+	// get the ID using VPP API
+	id, err := c.vpp.GetMsgID(msgName, msgCrc)
+	if err != nil {
+		error := fmt.Errorf("unable to retrieve message ID: %v", err)
+		log.WithFields(logger.Fields{
+			"msg_name": msgName,
+			"msg_crc":  msgCrc,
+		}).Errorf("unable to retrieve message ID: %v", err)
+		return id, error
+	}
+
+	c.msgIDsLock.Lock()
+	c.msgIDs[msgName+msgCrc] = id
+	c.msgIDsLock.Unlock()
+
+	return id, nil
+}