Merge pull request #120 from rosenhouse/get-peer

Adds GetVethPeerIfindex library function

Godeps/Godeps.json

@@ -226,6 +226,10 @@
 			"Comment": "v1.0-71-g2152b45",
 			"Rev": "2152b45fa28a361beba9aab0885972323a444e28"
 		},
+		{
+			"ImportPath": "github.com/safchain/ethtool",
+			"Rev": "7ff1ba29eca231991280817541cb3903f6be15d1"
+		},
 		{
 			"ImportPath": "github.com/vishvananda/netlink",
 			"Rev": "6e453822d85ef5721799774b654d4d02fed62afb"

pkg/ip/link_linux.go

@@ -23,6 +23,7 @@ import (
 
 	"github.com/containernetworking/plugins/pkg/ns"
 	"github.com/containernetworking/plugins/pkg/utils/hwaddr"
+	"github.com/safchain/ethtool"
 	"github.com/vishvananda/netlink"
 )
 
@@ -226,3 +227,43 @@ func SetHWAddrByIP(ifName string, ip4 net.IP, ip6 net.IP) error {
 
 	return nil
 }
+
+// GetVethPeerIfindex returns the veth link object, the peer ifindex of the
+// veth, or an error. This peer ifindex will only be valid in the peer's
+// network namespace.
+func GetVethPeerIfindex(ifName string) (netlink.Link, int, error) {
+	link, err := netlink.LinkByName(ifName)
+	if err != nil {
+		return nil, -1, fmt.Errorf("could not look up %q: %v", ifName, err)
+	}
+	if _, ok := link.(*netlink.Veth); !ok {
+		return nil, -1, fmt.Errorf("interface %q was not a veth interface", ifName)
+	}
+
+	// veth supports IFLA_LINK (what vishvananda/netlink calls ParentIndex)
+	// on 4.1 and higher kernels
+	peerIndex := link.Attrs().ParentIndex
+	if peerIndex <= 0 {
+		// Fall back to ethtool for 4.0 and earlier kernels
+		e, err := ethtool.NewEthtool()
+		if err != nil {
+			return nil, -1, fmt.Errorf("failed to initialize ethtool: %v", err)
+		}
+		defer e.Close()
+
+		stats, err := e.Stats(link.Attrs().Name)
+		if err != nil {
+			return nil, -1, fmt.Errorf("failed to request ethtool stats: %v", err)
+		}
+		n, ok := stats["peer_ifindex"]
+		if !ok {
+			return nil, -1, fmt.Errorf("failed to find 'peer_ifindex' in ethtool stats")
+		}
+		if n > 32767 || n == 0 {
+			return nil, -1, fmt.Errorf("invalid 'peer_ifindex' %d", n)
+		}
+		peerIndex = int(n)
+	}
+
+	return link, peerIndex, nil
+}

pkg/ip/link_linux_test.go

@@ -91,6 +91,46 @@ var _ = Describe("Link", func() {
 		rand.Reader = originalRandReader
 	})
 
+	Describe("GetVethPeerIfindex", func() {
+		It("returns the link and peer index of the named interface", func() {
+			By("looking up the container veth index using the host veth name")
+			_ = hostNetNS.Do(func(ns.NetNS) error {
+				defer GinkgoRecover()
+
+				gotHostLink, gotContainerIndex, err := ip.GetVethPeerIfindex(hostVethName)
+				Expect(err).NotTo(HaveOccurred())
+
+				By("checking we got back the host link")
+				attrs := gotHostLink.Attrs()
+				Expect(attrs.Index).To(Equal(hostVeth.Index))
+				Expect(attrs.Name).To(Equal(hostVeth.Name))
+
+				By("checking we got back the container veth index")
+				Expect(gotContainerIndex).To(Equal(containerVeth.Index))
+
+				return nil
+			})
+
+			By("looking up the host veth index using the container veth name")
+			_ = containerNetNS.Do(func(ns.NetNS) error {
+				defer GinkgoRecover()
+
+				gotContainerLink, gotHostIndex, err := ip.GetVethPeerIfindex(containerVethName)
+				Expect(err).NotTo(HaveOccurred())
+
+				By("checking we got back the container link")
+				attrs := gotContainerLink.Attrs()
+				Expect(attrs.Index).To(Equal(containerVeth.Index))
+				Expect(attrs.Name).To(Equal(containerVeth.Name))
+
+				By("checking we got back the host veth index")
+				Expect(gotHostIndex).To(Equal(hostVeth.Index))
+
+				return nil
+			})
+		})
+	})
+
 	It("SetupVeth must put the veth endpoints into the separate namespaces", func() {
 		_ = containerNetNS.Do(func(ns.NetNS) error {
 			defer GinkgoRecover()

vendor/github.com/safchain/ethtool/ethtool.go

@@ -0,0 +1,240 @@
+/*
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 ethtool  aims to provide a library giving a simple access to the
+// Linux SIOCETHTOOL ioctl operations. It can be used to retrieve informations
+// from a network device like statistics, driver related informations or
+// even the peer of a VETH interface.
+package ethtool
+
+import (
+	"bytes"
+	"fmt"
+	"syscall"
+	"unsafe"
+)
+
+// Maximum size of an interface name
+const (
+	IFNAMSIZ = 16
+)
+
+// ioctl ethtool request
+const (
+	SIOCETHTOOL = 0x8946
+)
+
+// ethtool stats related constants.
+const (
+	ETH_GSTRING_LEN  = 32
+	ETH_SS_STATS     = 1
+	ETHTOOL_GDRVINFO = 0x00000003
+	ETHTOOL_GSTRINGS = 0x0000001b
+	ETHTOOL_GSTATS   = 0x0000001d
+	// other CMDs from ethtool-copy.h of ethtool-3.5 package
+	ETHTOOL_GSET    = 0x00000001 /* Get settings. */
+	ETHTOOL_SSET    = 0x00000002 /* Set settings. */
+	ETHTOOL_GMSGLVL = 0x00000007 /* Get driver message level */
+	ETHTOOL_SMSGLVL = 0x00000008 /* Set driver msg level. */
+)
+
+// MAX_GSTRINGS maximum number of stats entries that ethtool can
+// retrieve currently.
+const (
+	MAX_GSTRINGS = 1000
+)
+
+type ifreq struct {
+	ifr_name [IFNAMSIZ]byte
+	ifr_data uintptr
+}
+
+type ethtoolDrvInfo struct {
+	cmd          uint32
+	driver       [32]byte
+	version      [32]byte
+	fw_version   [32]byte
+	bus_info     [32]byte
+	erom_version [32]byte
+	reserved2    [12]byte
+	n_priv_flags uint32
+	n_stats      uint32
+	testinfo_len uint32
+	eedump_len   uint32
+	regdump_len  uint32
+}
+
+type ethtoolGStrings struct {
+	cmd        uint32
+	string_set uint32
+	len        uint32
+	data       [MAX_GSTRINGS * ETH_GSTRING_LEN]byte
+}
+
+type ethtoolStats struct {
+	cmd     uint32
+	n_stats uint32
+	data    [MAX_GSTRINGS]uint64
+}
+
+type Ethtool struct {
+	fd int
+}
+
+// DriverName returns the driver name of the given interface.
+func (e *Ethtool) DriverName(intf string) (string, error) {
+	info, err := e.getDriverInfo(intf)
+	if err != nil {
+		return "", err
+	}
+	return string(bytes.Trim(info.driver[:], "\x00")), nil
+}
+
+// BusInfo returns the bus info of the given interface.
+func (e *Ethtool) BusInfo(intf string) (string, error) {
+	info, err := e.getDriverInfo(intf)
+	if err != nil {
+		return "", err
+	}
+	return string(bytes.Trim(info.bus_info[:], "\x00")), nil
+}
+
+func (e *Ethtool) getDriverInfo(intf string) (ethtoolDrvInfo, error) {
+	drvinfo := ethtoolDrvInfo{
+		cmd: ETHTOOL_GDRVINFO,
+	}
+
+	var name [IFNAMSIZ]byte
+	copy(name[:], []byte(intf))
+
+	ifr := ifreq{
+		ifr_name: name,
+		ifr_data: uintptr(unsafe.Pointer(&drvinfo)),
+	}
+
+	_, _, ep := syscall.Syscall(syscall.SYS_IOCTL, uintptr(e.fd), SIOCETHTOOL, uintptr(unsafe.Pointer(&ifr)))
+	if ep != 0 {
+		return ethtoolDrvInfo{}, syscall.Errno(ep)
+	}
+
+	return drvinfo, nil
+}
+
+// Stats retrieves stats of the given interface name.
+func (e *Ethtool) Stats(intf string) (map[string]uint64, error) {
+	drvinfo := ethtoolDrvInfo{
+		cmd: ETHTOOL_GDRVINFO,
+	}
+
+	var name [IFNAMSIZ]byte
+	copy(name[:], []byte(intf))
+
+	ifr := ifreq{
+		ifr_name: name,
+		ifr_data: uintptr(unsafe.Pointer(&drvinfo)),
+	}
+
+	_, _, ep := syscall.Syscall(syscall.SYS_IOCTL, uintptr(e.fd), SIOCETHTOOL, uintptr(unsafe.Pointer(&ifr)))
+	if ep != 0 {
+		return nil, syscall.Errno(ep)
+	}
+
+	if drvinfo.n_stats*ETH_GSTRING_LEN > MAX_GSTRINGS*ETH_GSTRING_LEN {
+		return nil, fmt.Errorf("ethtool currently doesn't support more than %d entries, received %d", MAX_GSTRINGS, drvinfo.n_stats)
+	}
+
+	gstrings := ethtoolGStrings{
+		cmd:        ETHTOOL_GSTRINGS,
+		string_set: ETH_SS_STATS,
+		len:        drvinfo.n_stats,
+		data:       [MAX_GSTRINGS * ETH_GSTRING_LEN]byte{},
+	}
+	ifr.ifr_data = uintptr(unsafe.Pointer(&gstrings))
+
+	_, _, ep = syscall.Syscall(syscall.SYS_IOCTL, uintptr(e.fd), SIOCETHTOOL, uintptr(unsafe.Pointer(&ifr)))
+	if ep != 0 {
+		return nil, syscall.Errno(ep)
+	}
+
+	stats := ethtoolStats{
+		cmd:     ETHTOOL_GSTATS,
+		n_stats: drvinfo.n_stats,
+		data:    [MAX_GSTRINGS]uint64{},
+	}
+
+	ifr.ifr_data = uintptr(unsafe.Pointer(&stats))
+
+	_, _, ep = syscall.Syscall(syscall.SYS_IOCTL, uintptr(e.fd), SIOCETHTOOL, uintptr(unsafe.Pointer(&ifr)))
+	if ep != 0 {
+		return nil, syscall.Errno(ep)
+	}
+
+	var result = make(map[string]uint64)
+	for i := 0; i != int(drvinfo.n_stats); i++ {
+		b := gstrings.data[i*ETH_GSTRING_LEN : i*ETH_GSTRING_LEN+ETH_GSTRING_LEN]
+		key := string(bytes.Trim(b, "\x00"))
+		result[key] = stats.data[i]
+	}
+
+	return result, nil
+}
+
+func (e *Ethtool) Close() {
+	syscall.Close(e.fd)
+}
+
+func NewEthtool() (*Ethtool, error) {
+	fd, _, err := syscall.RawSyscall(syscall.SYS_SOCKET, syscall.AF_INET, syscall.SOCK_DGRAM, syscall.IPPROTO_IP)
+	if err != 0 {
+		return nil, syscall.Errno(err)
+	}
+
+	return &Ethtool{
+		fd: int(fd),
+	}, nil
+}
+
+func BusInfo(intf string) (string, error) {
+	e, err := NewEthtool()
+	if err != nil {
+		return "", err
+	}
+	defer e.Close()
+	return e.BusInfo(intf)
+}
+
+func DriverName(intf string) (string, error) {
+	e, err := NewEthtool()
+	if err != nil {
+		return "", err
+	}
+	defer e.Close()
+	return e.DriverName(intf)
+}
+
+func Stats(intf string) (map[string]uint64, error) {
+	e, err := NewEthtool()
+	if err != nil {
+		return nil, err
+	}
+	defer e.Close()
+	return e.Stats(intf)
+}