devlink: initial commit

Author: mdlayher

.travis.yml

@@ -0,0 +1,16 @@
+language: go
+go:
+  - 1.x.x
+os:
+  - linux
+sudo: required
+before_install:
+  - go get github.com/golang/lint/golint
+  - go get honnef.co/go/tools/cmd/staticcheck
+  - go get -d ./...
+script:
+  - go build -tags=gofuzz ./...
+  - go vet ./...
+  - staticcheck ./...
+  - golint -set_exit_status ./...
+  - go test -v -race ./...

LICENSE.md

@@ -0,0 +1,10 @@
+MIT License
+===========
+
+Copyright (C) 2018 Matt Layher
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

README.md

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+devlink [![Build Status](https://travis-ci.org/mdlayher/devlink.svg?branch=master)](https://travis-ci.org/mdlayher/devlink) [![GoDoc](https://godoc.org/github.com/mdlayher/devlink?status.svg)](https://godoc.org/github.com/mdlayher/devlink) [![Go Report Card](https://goreportcard.com/badge/github.com/mdlayher/devlink)](https://goreportcard.com/report/github.com/mdlayher/devlink)
+=======
+
+Package `devlink` provides access to Linux's devlink interface.
+
+For more information on devlink, please see https://lwn.net/Articles/674867/.
+
+MIT Licensed.

client.go

@@ -0,0 +1,73 @@
+// Package devlink provides access to Linux's devlink interface.
+package devlink
+
+import (
+	"io"
+)
+
+// A Client provides access to Linux devlink information.
+type Client struct {
+	c osClient
+}
+
+// New creates a new Client.
+func New() (*Client, error) {
+	c, err := newClient()
+	if err != nil {
+		return nil, err
+	}
+
+	return &Client{
+		c: c,
+	}, nil
+}
+
+// Close releases resources used by a Client.
+func (c *Client) Close() error {
+	return c.c.Close()
+}
+
+// Devices retrieves all devlink devices on this system.
+func (c *Client) Devices() ([]*Device, error) {
+	return c.c.Devices()
+}
+
+// Ports retrieves all devlink ports attached to devices on this system.
+func (c *Client) Ports() ([]*Port, error) {
+	return c.c.Ports()
+}
+
+// An osClient is the operating system-specific implementation of Client.
+type osClient interface {
+	io.Closer
+	Devices() ([]*Device, error)
+	Ports() ([]*Port, error)
+}
+
+// A Device is a devlink device.
+type Device struct {
+	Bus    string
+	Device string
+}
+
+//go:generate stringer -type=PortType -output=string.go
+
+// A PortType is the operating mode of a devlink port.
+type PortType int
+
+// Possible PortType values.
+const (
+	Unknown PortType = iota
+	Auto
+	Ethernet
+	InfiniBand
+)
+
+// A Port is a devlink port which is attached to a devlink device.
+type Port struct {
+	Bus    string
+	Device string
+	Port   int
+	Type   PortType
+	Name   string
+}

client_linux.go

@@ -0,0 +1,144 @@
+//+build linux
+
+package devlink
+
+import (
+	"os"
+
+	"github.com/mdlayher/devlink/internal/dlh"
+	"github.com/mdlayher/genetlink"
+	"github.com/mdlayher/netlink"
+	"github.com/mdlayher/netlink/nlenc"
+)
+
+var _ osClient = &client{}
+
+// A client is a Linux-specific devlink client.
+type client struct {
+	c      *genetlink.Conn
+	family genetlink.Family
+}
+
+// newClient opens a connection to the devlink family using generic netlink.
+func newClient() (*client, error) {
+	c, err := genetlink.Dial(nil)
+	if err != nil {
+		return nil, err
+	}
+
+	return initClient(c)
+}
+
+// initClient is the internal client constructor used in some tests.
+func initClient(c *genetlink.Conn) (*client, error) {
+	f, err := c.GetFamily(dlh.GenlName)
+	if err != nil {
+		_ = c.Close()
+		return nil, err
+	}
+
+	return &client{
+		c:      c,
+		family: f,
+	}, nil
+}
+
+// Close implements osClient.
+func (c *client) Close() error {
+	return c.c.Close()
+}
+
+// Devices implements osClient.
+func (c *client) Devices() ([]*Device, error) {
+	msg := genetlink.Message{
+		Header: genetlink.Header{
+			Command: dlh.CmdGet,
+			Version: dlh.GenlVersion,
+		},
+	}
+
+	flags := netlink.HeaderFlagsRequest | netlink.HeaderFlagsDump
+
+	msgs, err := c.c.Execute(msg, c.family.ID, flags)
+	if err != nil {
+		return nil, err
+	}
+
+	return parseDevices(msgs)
+}
+
+// Ports implements osClient.
+func (c *client) Ports() ([]*Port, error) {
+	msg := genetlink.Message{
+		Header: genetlink.Header{
+			Command: dlh.CmdPortGet,
+			Version: dlh.GenlVersion,
+		},
+	}
+
+	flags := netlink.HeaderFlagsRequest | netlink.HeaderFlagsDump
+
+	msgs, err := c.c.Execute(msg, c.family.ID, flags)
+	if err != nil {
+		return nil, err
+	}
+
+	return parsePorts(msgs)
+}
+
+// parseDevices parses Devices from a slice of generic netlink messages.
+func parseDevices(msgs []genetlink.Message) ([]*Device, error) {
+	// It appears that a Device is just a subset of the attributes found in
+	// a Port, so we just call the port parsing function to avoid duplication.
+	ports, err := parsePorts(msgs)
+	if err != nil {
+		return nil, err
+	}
+
+	ds := make([]*Device, 0, len(msgs))
+	for _, p := range ports {
+		ds = append(ds, &Device{
+			Bus:    p.Bus,
+			Device: p.Device,
+		})
+	}
+
+	return ds, nil
+}
+
+// parsePorts parses Ports from a slice of generic netlink messages.
+func parsePorts(msgs []genetlink.Message) ([]*Port, error) {
+	if len(msgs) == 0 {
+		// No devlink response found.
+		return nil, os.ErrNotExist
+	}
+
+	ps := make([]*Port, 0, len(msgs))
+	for _, m := range msgs {
+		attrs, err := netlink.UnmarshalAttributes(m.Data)
+		if err != nil {
+			return nil, err
+		}
+
+		var p Port
+		for _, a := range attrs {
+			switch a.Type {
+			case dlh.AttrBusName:
+				p.Bus = nlenc.String(a.Data)
+			case dlh.AttrDevName:
+				p.Device = nlenc.String(a.Data)
+			case dlh.AttrPortIndex:
+				p.Port = int(nlenc.Uint32(a.Data))
+			case dlh.AttrPortType:
+				p.Type = PortType(nlenc.Uint16(a.Data))
+			// Allow netdev/ibdev name to share the same "Name" field.
+			case dlh.AttrPortNetdevName, dlh.AttrPortIbdevName:
+				p.Name = nlenc.String(a.Data)
+			}
+		}
+
+		ps = append(ps, &p)
+	}
+
+	return ps, nil
+}

client_linux_integration_test.go

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+//+build linux
+
+package devlink_test
+
+import (
+	"testing"
+
+	"github.com/mdlayher/devlink"
+)
+
+func TestLinuxClientIntegration(t *testing.T) {
+	c, err := devlink.New()
+	if err != nil {
+		t.Fatalf("failed to open client: %v", err)
+	}
+	defer c.Close()
+
+	// TODO(mdlayher): expand upon this.
+
+	t.Run("devices", func(t *testing.T) {
+		if _, err := c.Devices(); err != nil {
+			t.Fatalf("failed to get devices: %v", err)
+		}
+	})
+
+	t.Run("ports", func(t *testing.T) {
+		if _, err := c.Ports(); err != nil {
+			t.Fatalf("failed to get devices: %v", err)
+		}
+	})
+}

client_others.go

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+//+build !linux
+
+package devlink
+
+import (
+	"fmt"
+	"runtime"
+)
+
+var (
+	// errUnimplemented is returned by all functions on platforms that
+	// cannot make use of devlink.
+	errUnimplemented = fmt.Errorf("devlink not implemented on %s/%s",
+		runtime.GOOS, runtime.GOARCH)
+)
+
+var _ osClient = &client{}
+
+// A client is an unimplemented devlink client.
+type client struct{}
+
+// newClient always returns an error.
+func newClient() (*client, error) {
+	return nil, errUnimplemented
+}
+
+// Close implements osClient.
+func (c *client) Close() error {
+	return errUnimplemented
+}
+
+// CGroupStats implements osClient.
+func (c *client) Devices() ([]*Device, error) {
+	return nil, errUnimplemented
+}
+
+// PID implements osClient.
+func (c *client) Ports() ([]*Port, error) {
+	return nil, errUnimplemented
+}