Parse IFLA_PROTINFO in LinkDeserialize

Extract and parse IFLA_PROTINFO fields from RTM_NEWLINK AF_BRIDGE
netlink messages.

link.go

@@ -35,6 +35,7 @@ type LinkAttrs struct {
 	Promisc      int
 	Xdp          *LinkXdp
 	EncapType    string
+	Protinfo     *Protinfo
 }
 
 // NewLinkAttrs returns LinkAttrs structure filled with default values

link_linux.go

@@ -953,7 +953,7 @@ func execGetLink(req *nl.NetlinkRequest) (Link, error) {
 		return nil, fmt.Errorf("Link not found")
 
 	case len(msgs) == 1:
-		return LinkDeserialize(msgs[0])
+		return LinkDeserialize(nil, msgs[0])
 
 	default:
 		return nil, fmt.Errorf("More than one link found")
@@ -962,7 +962,7 @@ func execGetLink(req *nl.NetlinkRequest) (Link, error) {
 
 // linkDeserialize deserializes a raw message received from netlink into
 // a link object.
-func LinkDeserialize(m []byte) (Link, error) {
+func LinkDeserialize(hdr *syscall.NlMsghdr, m []byte) (Link, error) {
 	msg := nl.DeserializeIfInfomsg(m)
 
 	attrs, err := nl.ParseRouteAttr(m[msg.Len():])
@@ -1074,6 +1074,15 @@ func LinkDeserialize(m []byte) (Link, error) {
 				return nil, err
 			}
 			base.Xdp = xdp
+		case syscall.IFLA_PROTINFO | syscall.NLA_F_NESTED:
+			if hdr != nil && hdr.Type == syscall.RTM_NEWLINK &&
+				msg.Family == syscall.AF_BRIDGE {
+				attrs, err := nl.ParseRouteAttr(attr.Value[:])
+				if err != nil {
+					return nil, err
+				}
+				base.Protinfo = parseProtinfo(attrs)
+			}
 		}
 	}
 	// Links that don't have IFLA_INFO_KIND are hardware devices
@@ -1108,7 +1117,7 @@ func (h *Handle) LinkList() ([]Link, error) {
 
 	var res []Link
 	for _, m := range msgs {
-		link, err := LinkDeserialize(m)
+		link, err := LinkDeserialize(nil, m)
 		if err != nil {
 			return nil, err
 		}
@@ -1157,7 +1166,7 @@ func linkSubscribe(newNs, curNs netns.NsHandle, ch chan<- LinkUpdate, done <-cha
 			}
 			for _, m := range msgs {
 				ifmsg := nl.DeserializeIfInfomsg(m.Data)
-				link, err := LinkDeserialize(m.Data)
+				link, err := LinkDeserialize(&m.Header, m.Data)
 				if err != nil {
 					return
 				}

link_test.go

@@ -1006,3 +1006,55 @@ func TestLinkAddDelVti(t *testing.T) {
 		Local:     net.IPv4(127, 0, 0, 1),
 		Remote:    net.IPv4(127, 0, 0, 1)})
 }
+
+func TestLinkSubscribeWithProtinfo(t *testing.T) {
+	tearDown := setUpNetlinkTest(t)
+	defer tearDown()
+
+	master := &Bridge{LinkAttrs{Name: "foo"}}
+	if err := LinkAdd(master); err != nil {
+		t.Fatal(err)
+	}
+
+	slave := &Veth{
+		LinkAttrs: LinkAttrs{
+			Name:        "bar",
+			TxQLen:      testTxQLen,
+			MTU:         1400,
+			MasterIndex: master.Attrs().Index,
+		},
+		PeerName: "bar-peer",
+	}
+	if err := LinkAdd(slave); err != nil {
+		t.Fatal(err)
+	}
+
+	ch := make(chan LinkUpdate)
+	done := make(chan struct{})
+	defer close(done)
+	if err := LinkSubscribe(ch, done); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := LinkSetHairpin(slave, true); err != nil {
+		t.Fatal(err)
+	}
+
+	select {
+	case update := <-ch:
+		if !(update.Attrs().Name == "bar" && update.Attrs().Protinfo != nil &&
+			update.Attrs().Protinfo.Hairpin) {
+			t.Fatal("Hairpin update not received as expected")
+		}
+	case <-time.After(time.Minute):
+		t.Fatal("Hairpin update timed out")
+	}
+
+	if err := LinkDel(slave); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := LinkDel(master); err != nil {
+		t.Fatal(err)
+	}
+}

protinfo_linux.go

@@ -40,6 +40,15 @@ func (h *Handle) LinkGetProtinfo(link Link) (Protinfo, error) {
 			if err != nil {
 				return pi, err
 			}
+			pi = *parseProtinfo(infos)
+
+			return pi, nil
+		}
+	}
+	return pi, fmt.Errorf("Device with index %d not found", base.Index)
+}
+
+func parseProtinfo(infos []syscall.NetlinkRouteAttr) *Protinfo {
 	var pi Protinfo
 	for _, info := range infos {
 		switch info.Attr.Type {
@@ -57,8 +66,5 @@ func (h *Handle) LinkGetProtinfo(link Link) (Protinfo, error) {
 			pi.Flood = byteToBool(info.Value[0])
 		}
 	}
-			return pi, nil
+	return &pi
-		}
-	}
-	return pi, fmt.Errorf("Device with index %d not found", base.Index)
 }