1 // Copyright (c) 2017 Cisco and/or its affiliates.
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at:
7 // http://www.apache.org/licenses/LICENSE-2.0
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
23 "git.fd.io/govpp.git/api"
24 "github.com/lunixbochs/struc"
27 // MsgCodec provides encoding and decoding functionality of `api.Message` structs into/from
28 // binary format as accepted by VPP.
29 type MsgCodec struct{}
31 // VppRequestHeader struct contains header fields implemented by all VPP requests.
32 type VppRequestHeader struct {
38 // VppReplyHeader struct contains header fields implemented by all VPP replies.
39 type VppReplyHeader struct {
44 // VppEventHeader struct contains header fields implemented by all VPP events.
45 type VppEventHeader struct {
50 // VppOtherHeader struct contains header fields implemented by other VPP messages (not requests nor replies).
51 type VppOtherHeader struct {
55 // EncodeMsg encodes provided `Message` structure into its binary-encoded data representation.
56 func (*MsgCodec) EncodeMsg(msg api.Message, msgID uint16) (data []byte, err error) {
58 return nil, errors.New("nil message passed in")
61 // try to recover panic which might possibly occur in struc.Pack call
63 if r := recover(); r != nil {
65 if err, ok = r.(error); !ok {
66 err = fmt.Errorf("%v", r)
68 err = fmt.Errorf("panic occurred: %v", err)
72 var header interface{}
74 // encode message header
75 switch msg.GetMessageType() {
76 case api.RequestMessage:
77 header = &VppRequestHeader{VlMsgID: msgID}
78 case api.ReplyMessage:
79 header = &VppReplyHeader{VlMsgID: msgID}
80 case api.EventMessage:
81 header = &VppEventHeader{VlMsgID: msgID}
83 header = &VppOtherHeader{VlMsgID: msgID}
86 buf := new(bytes.Buffer)
88 // encode message header
89 if err := struc.Pack(buf, header); err != nil {
90 return nil, fmt.Errorf("failed to encode message header: %+v, error: %v", header, err)
93 // encode message content
94 if reflect.TypeOf(msg).Elem().NumField() > 0 {
95 if err := struc.Pack(buf, msg); err != nil {
96 return nil, fmt.Errorf("failed to encode message data: %+v, error: %v", data, err)
100 return buf.Bytes(), nil
103 // DecodeMsg decodes binary-encoded data of a message into provided `Message` structure.
104 func (*MsgCodec) DecodeMsg(data []byte, msg api.Message) error {
106 return errors.New("nil message passed in")
109 var header interface{}
111 // check which header is expected
112 switch msg.GetMessageType() {
113 case api.RequestMessage:
114 header = new(VppRequestHeader)
115 case api.ReplyMessage:
116 header = new(VppReplyHeader)
117 case api.EventMessage:
118 header = new(VppEventHeader)
120 header = new(VppOtherHeader)
123 buf := bytes.NewReader(data)
125 // decode message header
126 if err := struc.Unpack(buf, header); err != nil {
127 return fmt.Errorf("failed to decode message header: %+v, error: %v", header, err)
130 // decode message content
131 if err := struc.Unpack(buf, msg); err != nil {
132 return fmt.Errorf("failed to decode message data: %+v, error: %v", data, err)
138 func (*MsgCodec) DecodeMsgContext(data []byte, msg api.Message) (uint32, error) {
140 return 0, errors.New("nil message passed in")
143 var header interface{}
144 var getContext func() uint32
146 // check which header is expected
147 switch msg.GetMessageType() {
148 case api.RequestMessage:
149 header = new(VppRequestHeader)
150 getContext = func() uint32 { return header.(*VppRequestHeader).Context }
152 case api.ReplyMessage:
153 header = new(VppReplyHeader)
154 getContext = func() uint32 { return header.(*VppReplyHeader).Context }
160 buf := bytes.NewReader(data)
162 // decode message header
163 if err := struc.Unpack(buf, header); err != nil {
164 return 0, fmt.Errorf("decoding message header failed: %v", err)
167 return getContext(), nil