Merge pull request #3 from digitalocean/mdl-ovsnl-client

ovsnl: initial commit of Client

Author: mdlayher

ovsnl/client.go

@@ -0,0 +1,109 @@
+// Copyright 2017 DigitalOcean.
+//
+// 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 ovsnl
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/digitalocean/go-openvswitch/ovsnl/internal/ovsh"
+	"github.com/mdlayher/genetlink"
+)
+
+// A Client is a Linux Open vSwitch generic netlink client.
+type Client struct {
+	c *genetlink.Conn
+}
+
+// New creates a new Linux Open vSwitch generic netlink client.
+//
+// If no OvS generic netlink families are available on this system, an
+// error will be returned which can be checked using os.IsNotExist.
+func New() (*Client, error) {
+	c, err := genetlink.Dial(nil)
+	if err != nil {
+		return nil, err
+	}
+
+	return newClient(c)
+}
+
+// newClient is the internal Client constructor, used in tests.
+func newClient(c *genetlink.Conn) (*Client, error) {
+	// Must ensure that the generic netlink connection is closed on any errors
+	// that occur before it is returned to the caller.
+
+	families, err := c.ListFamilies()
+	if err != nil {
+		_ = c.Close()
+		return nil, err
+	}
+
+	client := &Client{c: c}
+	if err := client.init(families); err != nil {
+		_ = c.Close()
+		return nil, err
+	}
+
+	return client, nil
+}
+
+// Close closes the Client's generic netlink connection.
+func (c *Client) Close() error {
+	return c.c.Close()
+}
+
+// init initializes the generic netlink family service of Client.
+func (c *Client) init(families []genetlink.Family) error {
+	// Assume 4 families present.
+	var gotf int
+	const wantf = 4
+
+	for _, f := range families {
+		// Ignore any families without the OVS prefix.
+		if !strings.HasPrefix(f.Name, "ovs_") {
+			continue
+		}
+
+		gotf++
+		if err := c.initFamily(f); err != nil {
+			return err
+		}
+	}
+
+	// No families; return error for os.IsNotExist check.
+	if gotf == 0 {
+		return os.ErrNotExist
+	}
+
+	if gotf != wantf {
+		return fmt.Errorf("expected %d OVS generic netlink families, but found %d",
+			wantf, gotf)
+	}
+
+	return nil
+}
+
+// initFamily initializes a single generic netlink family service.
+func (c *Client) initFamily(f genetlink.Family) error {
+	switch f.Name {
+	case ovsh.DatapathFamily, ovsh.FlowFamily, ovsh.PacketFamily, ovsh.VportFamily:
+		// TODO(mdlayher): populate.
+		return nil
+	}
+
+	return fmt.Errorf("unrecognized OVS generic netlink family: %q", f.Name)
+}

ovsnl/client_linux_integration_test.go

@@ -0,0 +1,39 @@
+// Copyright 2017 DigitalOcean.
+//
+// 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.
+
+//+build linux
+
+package ovsnl_test
+
+import (
+	"os"
+	"testing"
+
+	"github.com/digitalocean/go-openvswitch/ovsnl"
+)
+
+func TestLinuxClientIntegration(t *testing.T) {
+	c, err := ovsnl.New()
+	if err != nil {
+		if os.IsNotExist(err) {
+			t.Skipf("generic netlink OVS families not found: %v", err)
+		}
+
+		t.Fatalf("failed to create client %v", err)
+	}
+	defer c.Close()
+
+	// TODO(mdlayher): fill in after Client has more methods.
+	_ = c
+}

ovsnl/client_linux_test.go

@@ -0,0 +1,127 @@
+// Copyright 2017 DigitalOcean.
+//
+// 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.
+
+//+build linux
+
+package ovsnl
+
+import (
+	"fmt"
+	"os"
+	"testing"
+
+	"github.com/digitalocean/go-openvswitch/ovsnl/internal/ovsh"
+	"github.com/mdlayher/genetlink"
+	"github.com/mdlayher/genetlink/genltest"
+	"github.com/mdlayher/netlink"
+	"github.com/mdlayher/netlink/nlenc"
+	"golang.org/x/sys/unix"
+)
+
+func TestClientNoFamiliesIsNotExist(t *testing.T) {
+	conn := genltest.Dial(func(greq genetlink.Message, nreq netlink.Message) ([]genetlink.Message, error) {
+		// Unrelated generic netlink families.
+		return familyMessages([]string{
+			"TASKSTATS",
+			"nl80211",
+		}), nil
+	})
+
+	_, err := newClient(conn)
+	if !os.IsNotExist(err) {
+		t.Fatalf("expected is not exist error, but got: %v", err)
+	}
+
+	t.Logf("OK error: %v", err)
+}
+
+func TestClientInvalidFamily(t *testing.T) {
+	conn := genltest.Dial(func(greq genetlink.Message, nreq netlink.Message) ([]genetlink.Message, error) {
+		return familyMessages([]string{
+			"ovs_foo",
+		}), nil
+	})
+
+	_, err := newClient(conn)
+	if err == nil {
+		t.Fatalf("expected an error, but none occurred")
+	}
+
+	t.Logf("OK error: %v", err)
+}
+
+func TestClientMissingFamilies(t *testing.T) {
+	conn := genltest.Dial(func(greq genetlink.Message, nreq netlink.Message) ([]genetlink.Message, error) {
+		// Too few OVS families.
+		return familyMessages([]string{
+			ovsh.DatapathFamily,
+		}), nil
+	})
+
+	_, err := newClient(conn)
+	if err == nil {
+		t.Fatalf("expected an error, but none occurred")
+	}
+
+	t.Logf("OK error: %v", err)
+}
+
+func TestClientOK(t *testing.T) {
+	conn := genltest.Dial(func(greq genetlink.Message, nreq netlink.Message) ([]genetlink.Message, error) {
+		return familyMessages([]string{
+			ovsh.DatapathFamily,
+			ovsh.FlowFamily,
+			ovsh.PacketFamily,
+			ovsh.VportFamily,
+		}), nil
+	})
+
+	_, err := newClient(conn)
+	if err != nil {
+		t.Fatalf("failed to create client: %v", err)
+	}
+}
+
+func familyMessages(families []string) []genetlink.Message {
+	msgs := make([]genetlink.Message, 0, len(families))
+
+	var id uint16
+	for _, f := range families {
+		msgs = append(msgs, genetlink.Message{
+			Data: mustMarshalAttributes([]netlink.Attribute{
+				{
+					Type: unix.CTRL_ATTR_FAMILY_ID,
+					Data: nlenc.Uint16Bytes(id),
+				},
+				{
+					Type: unix.CTRL_ATTR_FAMILY_NAME,
+					Data: nlenc.Bytes(f),
+				},
+			}),
+		})
+
+		id++
+	}
+
+	return msgs
+}
+
+func mustMarshalAttributes(attrs []netlink.Attribute) []byte {
+	b, err := netlink.MarshalAttributes(attrs)
+	if err != nil {
+		panic(fmt.Sprintf("failed to marshal attributes: %v", err))
+	}
+
+	return b
+}