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.
15 // +build !windows,!darwin
17 // Package vppapiclient is the default VPP adapter being used for the connection with VPP via shared memory.
18 // It is based on the communication with the vppapiclient VPP library written in C via CGO.
22 #cgo CFLAGS: -DPNG_DEBUG=1
23 #cgo LDFLAGS: -lvppapiclient
28 #include <arpa/inet.h>
29 #include <vpp-api/client/vppapiclient.h>
31 extern void go_msg_callback(uint16_t msg_id, void* data, size_t size);
33 typedef struct __attribute__((__packed__)) _req_header {
35 uint32_t client_index;
39 typedef struct __attribute__((__packed__)) _reply_header {
44 govpp_msg_callback (unsigned char *data, int size)
46 reply_header_t *header = ((reply_header_t *)data);
47 go_msg_callback(ntohs(header->msg_id), data, size);
51 govpp_send(uint32_t context, void *data, size_t size)
53 req_header_t *header = ((req_header_t *)data);
54 header->context = htonl(context);
55 return vac_write(data, size);
59 govpp_connect (char *shm)
61 return vac_connect("govpp", shm, govpp_msg_callback, 32);
67 return vac_disconnect();
71 govpp_get_msg_index(char *name_and_crc)
73 return vac_get_msg_index(name_and_crc);
85 "git.fd.io/govpp.git/adapter"
86 "github.com/fsnotify/fsnotify"
90 // watchedFolder is a folder where vpp's shared memory is supposed to be created.
91 // File system events are monitored in this folder.
92 watchedFolder = "/dev/shm/"
93 // watchedFile is a default name of the file in the watchedFolder. Once the file is present,
94 // the vpp is ready to accept a new connection.
95 watchedFile = "vpe-api"
98 // vppAPIClientAdapter is the opaque context of the adapter.
99 type vppAPIClientAdapter struct {
101 callback adapter.MsgCallback
104 var vppClient *vppAPIClientAdapter // global vpp API client adapter context
106 // NewVppAdapter returns a new vpp API client adapter.
107 func NewVppAdapter(shmPrefix string) adapter.VppAdapter {
108 return &vppAPIClientAdapter{
109 shmPrefix: shmPrefix,
113 // Connect connects the process to VPP.
114 func (a *vppAPIClientAdapter) Connect() error {
117 if a.shmPrefix == "" {
118 rc = C.govpp_connect(nil)
120 shm := C.CString(a.shmPrefix)
121 rc = C.govpp_connect(shm)
124 return fmt.Errorf("unable to connect to VPP (error=%d)", rc)
129 // Disconnect disconnects the process from VPP.
130 func (a *vppAPIClientAdapter) Disconnect() {
134 // GetMsgID returns a runtime message ID for the given message name and CRC.
135 func (a *vppAPIClientAdapter) GetMsgID(msgName string, msgCrc string) (uint16, error) {
136 nameAndCrc := C.CString(msgName + "_" + msgCrc)
137 defer C.free(unsafe.Pointer(nameAndCrc))
139 msgID := uint16(C.govpp_get_msg_index(nameAndCrc))
140 if msgID == ^uint16(0) {
141 // VPP does not know this message
142 return msgID, fmt.Errorf("unknown message: %v (crc: %v)", msgName, msgCrc)
148 // SendMsg sends a binary-encoded message to VPP.
149 func (a *vppAPIClientAdapter) SendMsg(context uint32, data []byte) error {
150 rc := C.govpp_send(C.uint32_t(context), unsafe.Pointer(&data[0]), C.size_t(len(data)))
152 return fmt.Errorf("unable to send the message (error=%d)", rc)
157 // SetMsgCallback sets a callback function that will be called by the adapter whenever a message comes from VPP.
158 func (a *vppAPIClientAdapter) SetMsgCallback(cb adapter.MsgCallback) {
162 // WaitReady blocks until shared memory for sending
163 // binary api calls is present on the file system.
164 func (a *vppAPIClientAdapter) WaitReady() error {
165 // Path to the shared memory segment
167 if a.shmPrefix == "" {
168 path = filepath.Join(watchedFolder, watchedFile)
170 path = filepath.Join(watchedFolder, a.shmPrefix+"-"+watchedFile)
173 // Watch folder if file does not exist yet
174 if !fileExists(path) {
175 watcher, err := fsnotify.NewWatcher()
179 defer watcher.Close()
181 if err := watcher.Add(watchedFolder); err != nil {
186 ev := <-watcher.Events
187 if ev.Name == path && (ev.Op&fsnotify.Create) == fsnotify.Create {
196 func fileExists(name string) bool {
197 if _, err := os.Stat(name); err != nil {
198 if os.IsNotExist(err) {
205 //export go_msg_callback
206 func go_msg_callback(msgID C.uint16_t, data unsafe.Pointer, size C.size_t) {
207 // convert unsafe.Pointer to byte slice
208 slice := &reflect.SliceHeader{Data: uintptr(data), Len: int(size), Cap: int(size)}
209 byteArr := *(*[]byte)(unsafe.Pointer(slice))
211 vppClient.callback(uint16(msgID), byteArr)