Fix chain elements init function

pkg/networkservice/mechanisms/vxlan/mtu/client.go

@@ -1,4 +1,4 @@
-// Copyright (c) 2021 Cisco and/or its affiliates.
+// Copyright (c) 2021-2022 Cisco and/or its affiliates.
 //
 // SPDX-License-Identifier: Apache-2.0
 //
@@ -20,12 +20,14 @@ import (
 	"context"
 	"net"
 	"sync"
+	"sync/atomic"
 
 	"git.fd.io/govpp.git/api"
-	"github.com/networkservicemesh/sdk/pkg/networkservice/core/next"
 	"google.golang.org/grpc"
 	"google.golang.org/protobuf/types/known/emptypb"
 
+	"github.com/networkservicemesh/sdk/pkg/networkservice/core/next"
+
 	"github.com/networkservicemesh/api/pkg/api/networkservice"
 	"github.com/networkservicemesh/api/pkg/api/networkservice/mechanisms/vxlan"
 )
@@ -34,8 +36,9 @@ type mtuClient struct {
 	vppConn  api.Connection
 	tunnelIP net.IP
 	mtu      uint32
-	initOnce sync.Once
-	err      error
+
+	inited    uint32
+	initMutex sync.Mutex
 }
 
 // NewClient - returns client chain element to manage vxlan MTU
@@ -70,8 +73,19 @@ func (m *mtuClient) Close(ctx context.Context, conn *networkservice.Connection,
 }
 
 func (m *mtuClient) init(ctx context.Context) error {
-	m.initOnce.Do(func() {
-		m.mtu, m.err = setMTU(ctx, m.vppConn, m.tunnelIP)
-	})
-	return m.err
+	if atomic.LoadUint32(&m.inited) > 0 {
+		return nil
+	}
+	m.initMutex.Lock()
+	defer m.initMutex.Unlock()
+	if atomic.LoadUint32(&m.inited) > 0 {
+		return nil
+	}
+
+	var err error
+	m.mtu, err = getMTU(ctx, m.vppConn, m.tunnelIP)
+	if err == nil {
+		atomic.StoreUint32(&m.inited, 1)
+	}
+	return err
 }

pkg/networkservice/mechanisms/vxlan/mtu/common.go

@@ -1,4 +1,4 @@
-// Copyright (c) 2020-2021 Cisco and/or its affiliates.
+// Copyright (c) 2020-2022 Cisco and/or its affiliates.
 //
 // SPDX-License-Identifier: Apache-2.0
 //
@@ -34,7 +34,7 @@ const (
 	overhead = 50
 )
 
-func setMTU(ctx context.Context, vppConn api.Connection, tunnelIP net.IP) (uint32, error) {
+func getMTU(ctx context.Context, vppConn api.Connection, tunnelIP net.IP) (uint32, error) {
 	client, err := interfaces.NewServiceClient(vppConn).SwInterfaceDump(ctx, &interfaces.SwInterfaceDump{})
 	if err != nil {
 		return 0, errors.Wrapf(err, "error attempting to get interface dump client to determine MTU for tunnelIP %q", tunnelIP)

pkg/networkservice/mechanisms/vxlan/mtu/server.go

@@ -1,4 +1,4 @@
-// Copyright (c) 2021 Cisco and/or its affiliates.
+// Copyright (c) 2021-2022 Cisco and/or its affiliates.
 //
 // SPDX-License-Identifier: Apache-2.0
 //
@@ -20,11 +20,13 @@ import (
 	"context"
 	"net"
 	"sync"
+	"sync/atomic"
 
 	"git.fd.io/govpp.git/api"
-	"github.com/networkservicemesh/sdk/pkg/networkservice/core/next"
 	"google.golang.org/protobuf/types/known/emptypb"
 
+	"github.com/networkservicemesh/sdk/pkg/networkservice/core/next"
+
 	"github.com/networkservicemesh/api/pkg/api/networkservice"
 	"github.com/networkservicemesh/api/pkg/api/networkservice/mechanisms/vxlan"
 )
@@ -33,8 +35,9 @@ type mtuServer struct {
 	vppConn  api.Connection
 	tunnelIP net.IP
 	mtu      uint32
-	initOnce sync.Once
-	err      error
+
+	inited    uint32
+	initMutex sync.Mutex
 }
 
 // NewServer - server chain element to manage vxlan MTU
@@ -76,8 +79,19 @@ func (m *mtuServer) Close(ctx context.Context, conn *networkservice.Connection)
 }
 
 func (m *mtuServer) init(ctx context.Context) error {
-	m.initOnce.Do(func() {
-		m.mtu, m.err = setMTU(ctx, m.vppConn, m.tunnelIP)
-	})
-	return m.err
+	if atomic.LoadUint32(&m.inited) > 0 {
+		return nil
+	}
+	m.initMutex.Lock()
+	defer m.initMutex.Unlock()
+	if atomic.LoadUint32(&m.inited) > 0 {
+		return nil
+	}
+
+	var err error
+	m.mtu, err = getMTU(ctx, m.vppConn, m.tunnelIP)
+	if err == nil {
+		atomic.StoreUint32(&m.inited, 1)
+	}
+	return err
 }

pkg/networkservice/mechanisms/wireguard/mtu/client.go

@@ -1,4 +1,4 @@
-// Copyright (c) 2021 Cisco and/or its affiliates.
+// Copyright (c) 2021-2022 Cisco and/or its affiliates.
 //
 // SPDX-License-Identifier: Apache-2.0
 //
@@ -20,6 +20,7 @@ import (
 	"context"
 	"net"
 	"sync"
+	"sync/atomic"
 
 	"git.fd.io/govpp.git/api"
 	"google.golang.org/grpc"
@@ -35,8 +36,9 @@ type mtuClient struct {
 	vppConn  api.Connection
 	tunnelIP net.IP
 	mtu      uint32
-	initOnce sync.Once
-	err      error
+
+	inited    uint32
+	initMutex sync.Mutex
 }
 
 // NewClient - returns client chain element to manage wireguard MTU
@@ -71,8 +73,19 @@ func (m *mtuClient) Close(ctx context.Context, conn *networkservice.Connection,
 }
 
 func (m *mtuClient) init(ctx context.Context) error {
-	m.initOnce.Do(func() {
-		m.mtu, m.err = setMTU(ctx, m.vppConn, m.tunnelIP)
-	})
-	return m.err
+	if atomic.LoadUint32(&m.inited) > 0 {
+		return nil
+	}
+	m.initMutex.Lock()
+	defer m.initMutex.Unlock()
+	if atomic.LoadUint32(&m.inited) > 0 {
+		return nil
+	}
+
+	var err error
+	m.mtu, err = getMTU(ctx, m.vppConn, m.tunnelIP)
+	if err == nil {
+		atomic.StoreUint32(&m.inited, 1)
+	}
+	return err
 }

pkg/networkservice/mechanisms/wireguard/mtu/common.go

@@ -1,4 +1,4 @@
-// Copyright (c) 2020-2021 Cisco and/or its affiliates.
+// Copyright (c) 2020-2022 Cisco and/or its affiliates.
 //
 // SPDX-License-Identifier: Apache-2.0
 //
@@ -34,7 +34,7 @@ const (
 	overhead = 80
 )
 
-func setMTU(ctx context.Context, vppConn api.Connection, tunnelIP net.IP) (uint32, error) {
+func getMTU(ctx context.Context, vppConn api.Connection, tunnelIP net.IP) (uint32, error) {
 	client, err := interfaces.NewServiceClient(vppConn).SwInterfaceDump(ctx, &interfaces.SwInterfaceDump{})
 	if err != nil {
 		return 0, errors.Wrapf(err, "error attempting to get interface dump client to determine MTU for tunnelIP %q", tunnelIP)

pkg/networkservice/mechanisms/wireguard/mtu/server.go

@@ -1,4 +1,4 @@
-// Copyright (c) 2021 Cisco and/or its affiliates.
+// Copyright (c) 2021-2022 Cisco and/or its affiliates.
 //
 // SPDX-License-Identifier: Apache-2.0
 //
@@ -20,6 +20,7 @@ import (
 	"context"
 	"net"
 	"sync"
+	"sync/atomic"
 
 	"git.fd.io/govpp.git/api"
 	"google.golang.org/protobuf/types/known/emptypb"
@@ -34,8 +35,9 @@ type mtuServer struct {
 	vppConn  api.Connection
 	tunnelIP net.IP
 	mtu      uint32
-	initOnce sync.Once
-	err      error
+
+	inited    uint32
+	initMutex sync.Mutex
 }
 
 // NewServer - server chain element to manage wireguard MTU
@@ -77,8 +79,19 @@ func (m *mtuServer) Close(ctx context.Context, conn *networkservice.Connection)
 }
 
 func (m *mtuServer) init(ctx context.Context) error {
-	m.initOnce.Do(func() {
-		m.mtu, m.err = setMTU(ctx, m.vppConn, m.tunnelIP)
-	})
-	return m.err
+	if atomic.LoadUint32(&m.inited) > 0 {
+		return nil
+	}
+	m.initMutex.Lock()
+	defer m.initMutex.Unlock()
+	if atomic.LoadUint32(&m.inited) > 0 {
+		return nil
+	}
+
+	var err error
+	m.mtu, err = getMTU(ctx, m.vppConn, m.tunnelIP)
+	if err == nil {
+		atomic.StoreUint32(&m.inited, 1)
+	}
+	return err
 }

pkg/networkservice/up/client.go

@@ -1,4 +1,4 @@
-// Copyright (c) 2020-2021 Cisco and/or its affiliates.
+// Copyright (c) 2020-2022 Cisco and/or its affiliates.
 //
 // SPDX-License-Identifier: Apache-2.0
 //
@@ -20,6 +20,7 @@ package up
 import (
 	"context"
 	"sync"
+	"sync/atomic"
 
 	"github.com/golang/protobuf/ptypes/empty"
 	"github.com/pkg/errors"
@@ -36,12 +37,12 @@ import (
 )
 
 type upClient struct {
-	ctx     context.Context
-	vppConn Connection
-	sync.Once
-	initErr error
-
+	ctx         context.Context
+	vppConn     Connection
 	loadIfIndex ifIndexFunc
+
+	inited    uint32
+	initMutex sync.Mutex
 }
 
 // NewClient provides a NetworkServiceClient chain elements that 'up's the swIfIndex
@@ -94,8 +95,18 @@ func (u *upClient) Close(ctx context.Context, conn *networkservice.Connection, o
 }
 
 func (u *upClient) init(ctx context.Context) error {
-	u.Do(func() {
-		u.initErr = initFunc(ctx, u.vppConn)
-	})
-	return u.initErr
+	if atomic.LoadUint32(&u.inited) > 0 {
+		return nil
+	}
+	u.initMutex.Lock()
+	defer u.initMutex.Unlock()
+	if atomic.LoadUint32(&u.inited) > 0 {
+		return nil
+	}
+
+	err := initFunc(ctx, u.vppConn)
+	if err == nil {
+		atomic.StoreUint32(&u.inited, 1)
+	}
+	return err
 }

pkg/networkservice/up/peerup/client.go

@@ -1,4 +1,4 @@
-// Copyright (c) 2021 Doc.ai and/or its affiliates.
+// Copyright (c) 2021-2022 Doc.ai and/or its affiliates.
 //
 // SPDX-License-Identifier: Apache-2.0
 //
@@ -19,7 +19,6 @@ package peerup
 
 import (
 	"context"
-	"sync"
 
 	"github.com/golang/protobuf/ptypes/empty"
 	"github.com/pkg/errors"
@@ -35,7 +34,6 @@ import (
 type peerupClient struct {
 	ctx     context.Context
 	vppConn Connection
-	sync.Once
 }
 
 // NewClient provides a NetworkServiceClient chain elements that 'up's the peer

pkg/networkservice/up/server.go

@@ -1,4 +1,4 @@
-// Copyright (c) 2020-2021 Cisco and/or its affiliates.
+// Copyright (c) 2020-2022 Cisco and/or its affiliates.
 //
 // SPDX-License-Identifier: Apache-2.0
 //
@@ -19,6 +19,7 @@ package up
 import (
 	"context"
 	"sync"
+	"sync/atomic"
 
 	"github.com/golang/protobuf/ptypes/empty"
 	"github.com/pkg/errors"
@@ -32,12 +33,12 @@ import (
 )
 
 type upServer struct {
-	ctx     context.Context
-	vppConn Connection
-	sync.Once
-	initErr error
-
+	ctx         context.Context
+	vppConn     Connection
 	loadIfIndex ifIndexFunc
+
+	inited    uint32
+	initMutex sync.Mutex
 }
 
 // NewServer provides a NetworkServiceServer chain elements that 'up's the swIfIndex
@@ -99,8 +100,18 @@ func (u *upServer) Close(ctx context.Context, conn *networkservice.Connection) (
 }
 
 func (u *upServer) init(ctx context.Context) error {
-	u.Do(func() {
-		u.initErr = initFunc(ctx, u.vppConn)
-	})
-	return u.initErr
+	if atomic.LoadUint32(&u.inited) > 0 {
+		return nil
+	}
+	u.initMutex.Lock()
+	defer u.initMutex.Unlock()
+	if atomic.LoadUint32(&u.inited) > 0 {
+		return nil
+	}
+
+	err := initFunc(ctx, u.vppConn)
+	if err == nil {
+		atomic.StoreUint32(&u.inited, 1)
+	}
+	return err
 }