Add support for setting Protinfo fields

Added new `Protinfo` datastructure, which contains fields from
`IFLA_PROTINFO | NLA_F_NESTED`. It is not embedded to `LinkAttrs`
because we need to use `NLM_F_DUMP` requests to get that info.

Signed-off-by: Alexander Morozov <lk4d4@docker.com>

protinfo.go

@@ -0,0 +1,110 @@
+package netlink
+
+import (
+	"fmt"
+	"syscall"
+
+	"github.com/vishvananda/netlink/nl"
+)
+
+type Protinfo struct {
+	Hairpin   bool
+	Guard     bool
+	FastLeave bool
+	RootBlock bool
+	Learning  bool
+	Flood     bool
+}
+
+func boolToByte(x bool) []byte {
+	if x {
+		return []byte{1}
+	}
+	return []byte{0}
+}
+
+func byteToBool(x byte) bool {
+	if uint8(x) != 0 {
+		return true
+	}
+	return false
+}
+
+func LinkGetProtinfo(link Link) (Protinfo, error) {
+	base := link.Attrs()
+	ensureIndex(base)
+	var pi Protinfo
+	req := nl.NewNetlinkRequest(syscall.RTM_GETLINK, syscall.NLM_F_DUMP)
+	msg := nl.NewIfInfomsg(syscall.AF_BRIDGE)
+	req.AddData(msg)
+	msgs, err := req.Execute(syscall.NETLINK_ROUTE, 0)
+	if err != nil {
+		return pi, err
+	}
+
+	for _, m := range msgs {
+		ans := nl.DeserializeIfInfomsg(m)
+		if int(ans.Index) != base.Index {
+			continue
+		}
+		attrs, err := nl.ParseRouteAttr(m[ans.Len():])
+		if err != nil {
+			return pi, err
+		}
+		for _, attr := range attrs {
+			if attr.Attr.Type != syscall.IFLA_PROTINFO|syscall.NLA_F_NESTED {
+				continue
+			}
+			infos, err := nl.ParseRouteAttr(attr.Value)
+			if err != nil {
+				return pi, err
+			}
+			var pi Protinfo
+			for _, info := range infos {
+				switch info.Attr.Type {
+				case nl.IFLA_BRPORT_MODE:
+					pi.Hairpin = byteToBool(info.Value[0])
+				case nl.IFLA_BRPORT_GUARD:
+					pi.Guard = byteToBool(info.Value[0])
+				case nl.IFLA_BRPORT_FAST_LEAVE:
+					pi.FastLeave = byteToBool(info.Value[0])
+				case nl.IFLA_BRPORT_PROTECT:
+					pi.RootBlock = byteToBool(info.Value[0])
+				case nl.IFLA_BRPORT_LEARNING:
+					pi.Learning = byteToBool(info.Value[0])
+				case nl.IFLA_BRPORT_UNICAST_FLOOD:
+					pi.Flood = byteToBool(info.Value[0])
+				}
+			}
+			return pi, nil
+		}
+	}
+	return pi, fmt.Errorf("Device with index %d not found", base.Index)
+}
+
+func LinkSetProtinfo(link Link, p Protinfo) error {
+	base := link.Attrs()
+	ensureIndex(base)
+	req := nl.NewNetlinkRequest(syscall.RTM_SETLINK, syscall.NLM_F_ACK)
+
+	msg := nl.NewIfInfomsg(syscall.AF_BRIDGE)
+	msg.Type = syscall.RTM_SETLINK
+	msg.Flags = syscall.NLM_F_REQUEST
+	msg.Index = int32(base.Index)
+	msg.Change = nl.DEFAULT_CHANGE
+	req.AddData(msg)
+
+	br := nl.NewRtAttr(syscall.IFLA_PROTINFO|syscall.NLA_F_NESTED, nil)
+	nl.NewRtAttrChild(br, nl.IFLA_BRPORT_MODE, boolToByte(p.Hairpin))
+	nl.NewRtAttrChild(br, nl.IFLA_BRPORT_GUARD, boolToByte(p.Guard))
+	nl.NewRtAttrChild(br, nl.IFLA_BRPORT_FAST_LEAVE, boolToByte(p.FastLeave))
+	nl.NewRtAttrChild(br, nl.IFLA_BRPORT_PROTECT, boolToByte(p.RootBlock))
+	nl.NewRtAttrChild(br, nl.IFLA_BRPORT_LEARNING, boolToByte(p.Learning))
+	nl.NewRtAttrChild(br, nl.IFLA_BRPORT_UNICAST_FLOOD, boolToByte(p.Flood))
+	req.AddData(br)
+	_, err := req.Execute(syscall.NETLINK_ROUTE, 0)
+	if err != nil {
+		return err
+	}
+	return nil
+}

protinfo_test.go

@@ -0,0 +1,76 @@
+package netlink
+
+import "testing"
+
+func TestProtinfo(t *testing.T) {
+	tearDown := setUpNetlinkTest(t)
+	defer tearDown()
+	master := &Bridge{LinkAttrs{Name: "foo"}}
+	if err := LinkAdd(master); err != nil {
+		t.Fatal(err)
+	}
+	iface1 := &Dummy{LinkAttrs{Name: "bar1", MasterIndex: master.Index}}
+	iface2 := &Dummy{LinkAttrs{Name: "bar2", MasterIndex: master.Index}}
+	iface3 := &Dummy{LinkAttrs{Name: "bar3"}}
+
+	if err := LinkAdd(iface1); err != nil {
+		t.Fatal(err)
+	}
+	if err := LinkAdd(iface2); err != nil {
+		t.Fatal(err)
+	}
+	if err := LinkAdd(iface3); err != nil {
+		t.Fatal(err)
+	}
+
+	pi1 := Protinfo{
+		Hairpin:   true,
+		RootBlock: true,
+	}
+
+	pi2 := Protinfo{
+		Guard:    true,
+		Learning: false,
+	}
+
+	pi3 := Protinfo{}
+
+	if err := LinkSetProtinfo(iface1, pi1); err != nil {
+		t.Fatal(err)
+	}
+
+	gpi1, err := LinkGetProtinfo(iface1)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !gpi1.Hairpin {
+		t.Fatalf("Hairpin mode is not enabled for %s, but should", iface1.Name)
+	}
+
+	if !gpi1.RootBlock {
+		t.Fatalf("RootBlock is not enabled for %s, but should", iface1.Name)
+	}
+
+	if err := LinkSetProtinfo(iface2, pi2); err != nil {
+		t.Fatal(err)
+	}
+	gpi2, err := LinkGetProtinfo(iface2)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if gpi2.Hairpin {
+		t.Fatalf("Hairpin mode is enabled for %s, but shouldn't", iface2.Name)
+	}
+
+	if !gpi2.Guard {
+		t.Fatalf("Guard is not enabled for %s, but should", iface2.Name)
+	}
+
+	if gpi2.Learning {
+		t.Fatalf("Learning is enabled for %s, but shouldn't", iface2.Name)
+	}
+
+	if err := LinkSetProtinfo(iface3, pi3); err == nil || err.Error() != "operation not supported" {
+		t.Fatal("Set protinfo for link without master is not supported, but err: %s", err)
+	}
+}