2 *------------------------------------------------------------------
3 * Copyright (c) 2020 Cisco and/or its affiliates.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at:
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 *------------------------------------------------------------------
18 // Package memif provides the implementation of shared memory interface (memif).
20 // Memif network interfaces communicate using UNIX domain socket. This socket
21 // must be first created using NewSocket(). Then interfaces can be added
22 // to this socket using NewInterface(). To start communication on each socket
23 // socket.StartPolling() must be called. socket.StopPolling() will stop
24 // the communication. When the interface changes link status Connected and
25 // Disconencted callbacks set in Arguments for each interface are called
26 // respectively. Once the interface is connected rx and tx queues can be
27 // aquired using interface.GetRxQueue() and interface.GetTxQueue().
28 // Packets can be transmitted by calling queue.ReadPacket() on rx queues and
29 // queue.WritePacket() on tx queues. If the interface is disconnected
30 // queue.ReadPacket() and queue.WritePacket() MUST not be called.
32 // Data transmission is backed by shared memory. The driver works in
33 // promiscuous mode only.
44 DefaultSocketFilename = "/run/vpp/memif.sock"
45 DefaultNumQueuePairs = 1
46 DefaultLog2RingSize = 10
47 DefaultPacketBufferSize = 2048
50 const mfd_allow_sealing = 2
51 const sys_memfd_create = 319
52 const f_add_seals = 1033
53 const f_seal_shrink = 0x0002
55 const efd_nonblock = 04000
57 // ConnectedFunc is a callback called when an interface is connected
58 type ConnectedFunc func(i *Interface) error
60 // DisconnectedFunc is a callback called when an interface is disconnected
61 type DisconnectedFunc func(i *Interface) error
63 // MemoryConfig represents shared memory configuration
64 type MemoryConfig struct {
65 NumQueuePairs uint16 // number of queue pairs
66 Log2RingSize uint8 // ring size as log2
67 PacketBufferSize uint32 // size of single packet buffer
70 // Arguments represent interface configuration
71 type Arguments struct {
72 Id uint32 // Interface identifier unique across socket. Used to identify peer interface when connecting
73 IsMaster bool // Interface role master/slave
76 Secret [24]byte // optional parameter, secrets of the interfaces must match if they are to connect
77 MemoryConfig MemoryConfig
78 ConnectedFunc ConnectedFunc // callback called when interface changes status to connected
79 DisconnectedFunc DisconnectedFunc // callback called when interface changes status to disconnected
80 PrivateData interface{} // private data used by client program
83 // memoryRegion represents a shared memory mapped file
84 type memoryRegion struct {
88 packetBufferOffset uint32
91 // Queue represents rx or tx queue
100 // Interface represents memif network interface
101 type Interface struct {
104 privateData interface{}
105 listRef *list.Element
110 regions []memoryRegion
115 // IsMaster returns true if the interfaces role is master, else returns false
116 func (i *Interface) IsMaster() bool {
117 return i.args.IsMaster
120 // GetRemoteName returns the name of the application on which the peer
122 func (i *Interface) GetRemoteName() string {
126 // GetPeerName returns peer interfaces name
127 func (i *Interface) GetPeerName() string {
131 // GetName returens interfaces name
132 func (i *Interface) GetName() string {
136 // GetMemoryConfig returns interfaces active memory config.
137 // If interface is not connected the config is invalid.
138 func (i *Interface) GetMemoryConfig() MemoryConfig {
142 // GetRxQueue returns an rx queue specified by queue index
143 func (i *Interface) GetRxQueue(qid int) (*Queue, error) {
144 if qid >= len(i.rxQueues) {
145 return nil, fmt.Errorf("Invalid Queue index")
147 return &i.rxQueues[qid], nil
150 // GetRxQueue returns a tx queue specified by queue index
151 func (i *Interface) GetTxQueue(qid int) (*Queue, error) {
152 if qid >= len(i.txQueues) {
153 return nil, fmt.Errorf("Invalid Queue index")
155 return &i.txQueues[qid], nil
158 // GetEventFd returns queues interrupt event fd
159 func (q *Queue) GetEventFd() (int, error) {
160 return q.interruptFd, nil
163 // GetFilename returns sockets filename
164 func (socket *Socket) GetFilename() string {
165 return socket.filename
168 // close closes the queue
169 func (q *Queue) close() {
170 syscall.Close(q.interruptFd)
173 // IsConnecting returns true if the interface is connecting
174 func (i *Interface) IsConnecting() bool {
181 // IsConnected returns true if the interface is connected
182 func (i *Interface) IsConnected() bool {
183 if i.cc != nil && i.cc.isConnected {
189 // Disconnect disconnects the interface
190 func (i *Interface) Disconnect() (err error) {
192 // close control and disconenct interface
193 return i.cc.close(true, "Interface disconnected")
198 // disconnect finalizes interface disconnection
199 func (i *Interface) disconnect() (err error) {
200 if i.cc == nil { // disconnected
204 err = i.args.DisconnectedFunc(i)
206 return fmt.Errorf("DisconnectedFunc: ", err)
209 for _, q := range i.txQueues {
212 i.txQueues = []Queue{}
214 for _, q := range i.rxQueues {
217 i.rxQueues = []Queue{}
220 for _, r := range i.regions {
221 err = syscall.Munmap(r.data)
225 err = syscall.Close(r.fd)
239 // Delete deletes the interface
240 func (i *Interface) Delete() (err error) {
243 // remove referance on socket
244 i.socket.interfaceList.Remove(i.listRef)
250 // GetSocket returns the socket the interface belongs to
251 func (i *Interface) GetSocket() *Socket {
255 // GetPrivateDate returns interfaces private data
256 func (i *Interface) GetPrivateData() interface{} {
257 return i.args.PrivateData
260 // GetId returns interfaces id
261 func (i *Interface) GetId() uint32 {
265 // RoleToString returns 'Master' if isMaster os true, else returns 'Slave'
266 func RoleToString(isMaster bool) string {
273 // RequestConnection is used by slave interface to connect to a socket and
274 // create a control channel
275 func (i *Interface) RequestConnection() error {
277 return fmt.Errorf("Only slave can request connection")
280 fd, err := syscall.Socket(syscall.AF_UNIX, syscall.SOCK_SEQPACKET, 0)
282 return fmt.Errorf("Failed to create UNIX domain socket: %v", err)
284 usa := &syscall.SockaddrUnix{Name: i.socket.filename}
286 // Connect to listener socket
287 err = syscall.Connect(fd, usa)
289 return fmt.Errorf("Failed to connect socket %s : %v", i.socket.filename, err)
292 // Create control channel
293 i.cc, err = i.socket.addControlChannel(fd, i)
295 return fmt.Errorf("Failed to create control channel: %v", err)
301 // NewInterface returns a new memif network interface. When creating an interface
302 // it's id must be unique across socket with the exception of loopback interface
303 // in which case the id is the same but role differs
304 func (socket *Socket) NewInterface(args *Arguments) (*Interface, error) {
306 // make sure the ID is unique on this socket
307 for elt := socket.interfaceList.Front(); elt != nil; elt = elt.Next() {
308 i, ok := elt.Value.(*Interface)
310 if i.args.Id == args.Id && i.args.IsMaster == args.IsMaster {
311 return nil, fmt.Errorf("Interface with id %u role %s already exists on this socket", args.Id, RoleToString(args.IsMaster))
316 // copy interface configuration
320 // set default values
321 if i.args.MemoryConfig.NumQueuePairs == 0 {
322 i.args.MemoryConfig.NumQueuePairs = DefaultNumQueuePairs
324 if i.args.MemoryConfig.Log2RingSize == 0 {
325 i.args.MemoryConfig.Log2RingSize = DefaultLog2RingSize
327 if i.args.MemoryConfig.PacketBufferSize == 0 {
328 i.args.MemoryConfig.PacketBufferSize = DefaultPacketBufferSize
333 // append interface to the list
334 i.listRef = socket.interfaceList.PushBack(&i)
337 if socket.listener == nil {
338 err = socket.addListener()
340 return nil, fmt.Errorf("Failed to create listener channel: %s", err)
348 // eventFd returns an eventfd (SYS_EVENTFD2)
349 func eventFd() (efd int, err error) {
350 u_efd, _, errno := syscall.Syscall(syscall.SYS_EVENTFD2, uintptr(0), uintptr(efd_nonblock), 0)
352 return -1, os.NewSyscallError("eventfd", errno)
354 return int(u_efd), nil
357 // addRegions creates and adds a new memory region to the interface (slave only)
358 func (i *Interface) addRegion(hasPacketBuffers bool, hasRings bool) (err error) {
362 r.packetBufferOffset = uint32((i.run.NumQueuePairs + i.run.NumQueuePairs) * (ringSize + descSize*(1<<i.run.Log2RingSize)))
364 r.packetBufferOffset = 0
367 if hasPacketBuffers {
368 r.size = uint64(r.packetBufferOffset + i.run.PacketBufferSize*uint32(1<<i.run.Log2RingSize)*uint32(i.run.NumQueuePairs+i.run.NumQueuePairs))
370 r.size = uint64(r.packetBufferOffset)
373 r.fd, err = memfdCreate()
378 _, _, errno := syscall.Syscall(syscall.SYS_FCNTL, uintptr(r.fd), uintptr(f_add_seals), uintptr(f_seal_shrink))
381 return fmt.Errorf("memfdCreate: %s", os.NewSyscallError("fcntl", errno))
384 err = syscall.Ftruncate(r.fd, int64(r.size))
388 return fmt.Errorf("memfdCreate: %s", err)
391 r.data, err = syscall.Mmap(r.fd, 0, int(r.size), syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_SHARED)
393 return fmt.Errorf("addRegion: %s", err)
396 i.regions = append(i.regions, r)
401 // initializeRegions initializes interfaces regions (slave only)
402 func (i *Interface) initializeRegions() (err error) {
404 err = i.addRegion(true, true)
406 return fmt.Errorf("initializeRegions: %s", err)
412 // initializeQueues initializes interfaces queues (slave only)
413 func (i *Interface) initializeQueues() (err error) {
421 desc.setLength(int(i.run.PacketBufferSize))
423 for qid := 0; qid < int(i.run.NumQueuePairs); qid++ {
426 ring: i.newRing(0, ringTypeS2M, qid),
431 q.ring.setCookie(cookie)
433 q.interruptFd, err = eventFd()
438 i.txQueues = append(i.txQueues, *q)
440 for j := 0; j < q.ring.size; j++ {
441 slot = qid*q.ring.size + j
442 desc.setOffset(int(i.regions[0].packetBufferOffset + uint32(slot)*i.run.PacketBufferSize))
443 q.putDescBuf(slot, desc)
446 for qid := 0; qid < int(i.run.NumQueuePairs); qid++ {
449 ring: i.newRing(0, ringTypeM2S, qid),
454 q.ring.setCookie(cookie)
456 q.interruptFd, err = eventFd()
461 i.rxQueues = append(i.rxQueues, *q)
463 for j := 0; j < q.ring.size; j++ {
464 slot = qid*q.ring.size + j
465 desc.setOffset(int(i.regions[0].packetBufferOffset + uint32(slot)*i.run.PacketBufferSize))
466 q.putDescBuf(slot, desc)
473 // connect finalizes interface connection
474 func (i *Interface) connect() (err error) {
475 for rid, _ := range i.regions {
478 r.data, err = syscall.Mmap(r.fd, 0, int(r.size), syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_SHARED)
480 return fmt.Errorf("Mmap: %s", err)
485 for _, q := range i.txQueues {
488 if q.ring.getCookie() != cookie {
489 return fmt.Errorf("Wrong cookie")
496 for _, q := range i.rxQueues {
499 if q.ring.getCookie() != cookie {
500 return fmt.Errorf("Wrong cookie")
507 return i.args.ConnectedFunc(i)