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// 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"
)
// 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(error)
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
}
if log.Level == logger.DebugLevel { // for performance reasons - logrus does some processing even if debugs are disabled
log.WithFields(logger.Fields{
"context": chMeta.id,
"msg_id": msgID,
"msg_size": len(data),
}).Debug("Sending a message to VPP.")
}
// send the message
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
pingData, _ := c.codec.EncodeMsg(msgControlPing, 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
}
if log.Level == logger.DebugLevel { // for performance reasons - logrus does some processing even if debugs are disabled
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,
}).Error(error)
return id, error
}
c.msgIDsLock.Lock()
c.msgIDs[msgName+msgCrc] = id
c.msgIDsLock.Unlock()
return id, nil
}
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