Move container attachment from sh to Go

common/utils.go

@@ -2,12 +2,14 @@ package common
 
 import (
 	"fmt"
-	"github.com/vishvananda/netlink"
-	"github.com/vishvananda/netns"
 	"net"
 	"os"
-	"runtime"
 	"strings"
+
+	"github.com/vishvananda/netlink"
+	"github.com/vishvananda/netns"
+
+	weavenet "github.com/weaveworks/weave/net"
 )
 
 // Assert test is true, panic otherwise
@@ -25,25 +27,6 @@ func ErrorMessages(errors []error) string {
 	return strings.Join(result, "\n")
 }
 
-func WithNetNS(ns netns.NsHandle, work func() error) error {
-	runtime.LockOSThread()
-	defer runtime.UnlockOSThread()
-
-	oldNs, err := netns.Get()
-	if err == nil {
-		defer oldNs.Close()
-
-		err = netns.Set(ns)
-		if err == nil {
-			defer netns.Set(oldNs)
-
-			err = work()
-		}
-	}
-
-	return err
-}
-
 type NetDev struct {
 	Name  string
 	MAC   net.HardwareAddr
@@ -63,7 +46,7 @@ func FindNetDevs(processID int, match func(link netlink.Link) bool) ([]NetDev, e
 	}
 	defer ns.Close()
 
-	err = WithNetNS(ns, func() error {
+	err = weavenet.WithNetNS(ns, func() error {
 		return forEachLink(func(link netlink.Link) error {
 			if match(link) {
 				netDev, err := linkToNetDev(link)

common/arp.go → net/arp.go

@@ -1,4 +1,4 @@
-package common
+package net
 
 import "fmt"
 import "io"

net/bridge.go

@@ -0,0 +1,53 @@
+package net
+
+import (
+	"github.com/vishvananda/netlink"
+)
+
+type BridgeType int
+
+const (
+	WeaveBridgeName = "weave"
+	DatapathName    = "datapath"
+
+	None BridgeType = iota
+	Bridge
+	Fastdp
+	BridgedFastdp
+	Inconsistent
+)
+
+func DetectBridgeType(weaveBridgeName, datapathName string) BridgeType {
+	bridge, _ := netlink.LinkByName(weaveBridgeName)
+	datapath, _ := netlink.LinkByName(datapathName)
+
+	switch {
+	case bridge == nil && datapath == nil:
+		return None
+	case isBridge(bridge) && datapath == nil:
+		return Bridge
+	case isDatapath(bridge) && datapath == nil:
+		return Fastdp
+	case isDatapath(datapath) && isBridge(bridge):
+		return BridgedFastdp
+	default:
+		return Inconsistent
+	}
+}
+
+func isBridge(link netlink.Link) bool {
+	_, isBridge := link.(*netlink.Bridge)
+	return isBridge
+}
+
+func isDatapath(link netlink.Link) bool {
+	switch link.(type) {
+	case *netlink.GenericLink:
+		return link.Type() == "openvswitch"
+	case *netlink.Device:
+		// Assume it's our openvswitch device, and the kernel has not been updated to report the kind.
+		return true
+	default:
+		return false
+	}
+}

net/ethtool.go

@@ -0,0 +1,52 @@
+package net
+
+import "fmt"
+import "syscall"
+import "unsafe"
+
+const (
+	SIOCETHTOOL     = 0x8946     // linux/sockios.h
+	ETHTOOL_STXCSUM = 0x00000017 // linux/ethtool.h
+	IFNAMSIZ        = 16         // linux/if.h
+)
+
+// linux/if.h 'struct ifreq'
+type IFReqData struct {
+	Name [IFNAMSIZ]byte
+	Data uintptr
+}
+
+// linux/ethtool.h 'struct ethtool_value'
+type EthtoolValue struct {
+	Cmd  uint32
+	Data uint32
+}
+
+// Disable TX checksum offload on specified interface
+func EthtoolTXOff(name string) error {
+	if len(name)+1 > IFNAMSIZ {
+		return fmt.Errorf("name too long")
+	}
+
+	value := EthtoolValue{ETHTOOL_STXCSUM, 0}
+	request := IFReqData{Data: uintptr(unsafe.Pointer(&value))}
+
+	copy(request.Name[:], name)
+
+	socket, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_DGRAM, 0)
+	if err != nil {
+		return err
+	}
+	defer syscall.Close(socket)
+
+	_, _, errno := syscall.RawSyscall(syscall.SYS_IOCTL,
+		uintptr(socket),
+		uintptr(SIOCETHTOOL),
+		uintptr(unsafe.Pointer(&request)))
+
+	if errno != 0 {
+		return errno
+	}
+
+	return nil
+}

net/netns.go

@@ -0,0 +1,37 @@
+package net
+
+import (
+	"runtime"
+
+	"github.com/vishvananda/netlink"
+	"github.com/vishvananda/netns"
+)
+
+func WithNetNS(ns netns.NsHandle, work func() error) error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	oldNs, err := netns.Get()
+	if err == nil {
+		defer oldNs.Close()
+
+		err = netns.Set(ns)
+		if err == nil {
+			defer netns.Set(oldNs)
+
+			err = work()
+		}
+	}
+
+	return err
+}
+
+func WithNetNSLink(ns netns.NsHandle, ifName string, work func(link netlink.Link) error) error {
+	return WithNetNS(ns, func() error {
+		link, err := netlink.LinkByName(ifName)
+		if err != nil {
+			return err
+		}
+		return work(link)
+	})
+}

net/route.go

@@ -3,6 +3,7 @@ package net
 import (
 	"fmt"
 	"net"
+	"os"
 
 	"github.com/vishvananda/netlink"
 )
@@ -55,3 +56,16 @@ func forEachRoute(ignoreIfaceNames map[string]struct{}, check func(r netlink.Rou
 	}
 	return nil
 }
+
+func AddRoute(link netlink.Link, scope netlink.Scope, dst *net.IPNet, gw net.IP) error {
+	err := netlink.RouteAdd(&netlink.Route{
+		LinkIndex: link.Attrs().Index,
+		Scope:     scope,
+		Dst:       dst,
+		Gw:        gw,
+	})
+	if os.IsExist(err) { // squash duplicate route errors
+		err = nil
+	}
+	return err
+}