connection: prevent channel ID overlap

[govpp.git] / core / channel.go

diff --git a/core/channel.go b/core/channel.go
index 1086c36..112c14e 100644 (file)
--- a/core/channel.go
+++ b/core/channel.go
@@ -19,7 +19,6 @@ import (
        "fmt"
        "reflect"
        "strings"
-       "sync/atomic"
        "time"
 
        "github.com/sirupsen/logrus"
@@ -110,11 +109,9 @@ type Channel struct {
        receiveReplyTimeout time.Duration // maximum time that we wait for receiver to consume reply
 }
 
-func (c *Connection) newChannel(reqChanBufSize, replyChanBufSize int) *Channel {
+func (c *Connection) newChannel(reqChanBufSize, replyChanBufSize int) (*Channel, error) {
        // create new channel
-       chID := uint16(atomic.AddUint32(&c.maxChannelID, 1) & 0x7fff)
        channel := &Channel{
-               id:                  chID,
                conn:                c,
                msgCodec:            c.codec,
                msgIdentifier:       c,
@@ -126,10 +123,22 @@ func (c *Connection) newChannel(reqChanBufSize, replyChanBufSize int) *Channel {
 
        // store API channel within the client
        c.channelsLock.Lock()
-       c.channels[chID] = channel
+       if len(c.channels) >= 0x7fff {
+               return nil, errors.New("all channel IDs are used")
+       }
+       for {
+               c.nextChannelID++
+               chID := c.nextChannelID & 0x7fff
+               _, ok := c.channels[chID]
+               if !ok {
+                       channel.id = chID
+                       c.channels[chID] = channel
+                       break
+               }
+       }
        c.channelsLock.Unlock()
 
-       return channel
+       return channel, nil
 }
 
 func (ch *Channel) GetID() uint16 {