Add ParseRouteAttrAsMap helper function

This will allow to parse nl attributes, returning a map
for easy access to each attribute.

Signed-off-by: adrianc <adrianc@nvidia.com>

nl/nl_linux.go

@@ -910,6 +910,22 @@ func ParseRouteAttr(b []byte) ([]syscall.NetlinkRouteAttr, error) {
 	return attrs, nil
 }
 
+// ParseRouteAttrAsMap parses provided buffer that contains raw RtAttrs and returns a map of parsed
+// atttributes indexed by attribute type or error if occured.
+func ParseRouteAttrAsMap(b []byte) (map[uint16]syscall.NetlinkRouteAttr, error) {
+	attrMap := make(map[uint16]syscall.NetlinkRouteAttr)
+
+	attrs, err := ParseRouteAttr(b)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, attr := range attrs {
+		attrMap[attr.Attr.Type] = attr
+	}
+	return attrMap, nil
+}
+
 func netlinkRouteAttrAndValue(b []byte) (*unix.RtAttr, []byte, int, error) {
 	a := (*unix.RtAttr)(unsafe.Pointer(&b[0]))
 	if int(a.Len) < unix.SizeofRtAttr || int(a.Len) > len(b) {

nl/nl_linux_test.go

@@ -130,3 +130,25 @@ func TestCnMsgOpDeserializeSerialize(t *testing.T) {
 	msg := DeserializeCnMsgOp(orig)
 	testDeserializeSerialize(t, orig, safemsg, msg)
 }
+
+func TestParseRouteAttrAsMap(t *testing.T) {
+	attr1 := NewRtAttr(0x1, ZeroTerminated("foo"))
+	attr2 := NewRtAttr(0x2, ZeroTerminated("bar"))
+	raw := make([]byte, 0)
+	raw = append(raw, attr1.Serialize()...)
+	raw = append(raw, attr2.Serialize()...)
+	attrs, err := ParseRouteAttrAsMap(raw)
+	if err != nil {
+		t.Errorf("failed to parse route attributes %s", err)
+	}
+
+	attr, ok := attrs[0x1]
+	if !ok || BytesToString(attr.Value) != "foo" {
+		t.Error("missing/incorrect \"foo\" attribute")
+	}
+
+	attr, ok = attrs[0x2]
+	if !ok || BytesToString(attr.Value) != "bar" {
+		t.Error("missing/incorrect \"bar\" attribute")
+	}
+}