1 files changed, 345 insertions, 0 deletions
diff --git a/extras/gomemif/memif/memif.go b/extras/gomemif/memif/memif.go
new file mode 100644
index 00000000000..1a7857de03e
--- /dev/null
+++ b/extras/gomemif/memif/memif.go
@@ -0,0 +1,345 @@
+/*
+ *------------------------------------------------------------------
+ * Copyright (c) 2020 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *------------------------------------------------------------------
+ */
+
+package memif
+
+import (
+	"encoding/binary"
+	"fmt"
+	"syscall"
+)
+
+const cookie = 0x3E31F20
+
+// VersionMajor is memif protocols major version
+const VersionMajor = 2
+
+// VersionMinor is memif protocols minor version
+const VersionMinor = 0
+
+// Version is memif protocols version as uint16
+// (M-Major m-minor: MMMMMMMMmmmmmmmm)
+const Version = ((VersionMajor << 8) | VersionMinor)
+
+type msgType uint16
+
+const (
+	msgTypeNone msgType = iota
+	msgTypeAck
+	msgTypeHello
+	msgTypeInit
+	msgTypeAddRegion
+	msgTypeAddRing
+	msgTypeConnect
+	msgTypeConnected
+	msgTypeDisconnect
+)
+
+type interfaceMode uint8
+
+const (
+	interfaceModeEthernet interfaceMode = iota
+	interfaceModeIp
+	interfaceModePuntInject
+)
+
+const msgSize = 128
+const msgTypeSize = 2
+
+const msgAddRingFlagS2M = (1 << 0)
+
+// Descriptor flags
+//
+// next buffer present
+const descFlagNext = (1 << 0)
+
+// Ring flags
+//
+// Interrupt
+const ringFlagInterrupt = 1
+
+func min16(a uint16, b uint16) uint16 {
+	if a < b {
+		return a
+	}
+	return b
+}
+
+func min8(a uint8, b uint8) uint8 {
+	if a < b {
+		return a
+	}
+	return b
+}
+
+type MsgHello struct {
+	// app name
+	Name            [32]byte
+	VersionMin      uint16
+	VersionMax      uint16
+	MaxRegion       uint16
+	MaxRingM2S      uint16
+	MaxRingS2M      uint16
+	MaxLog2RingSize uint8
+}
+
+type MsgInit struct {
+	Version uint16
+	Id      uint32
+	Mode    interfaceMode
+	Secret  [24]byte
+	// app name
+	Name [32]byte
+}
+
+type MsgAddRegion struct {
+	Index uint16
+	Size  uint64
+}
+
+type MsgAddRing struct {
+	Flags          uint16
+	Index          uint16
+	Region         uint16
+	Offset         uint32
+	RingSizeLog2   uint8
+	PrivateHdrSize uint16
+}
+
+type MsgConnect struct {
+	// interface name
+	Name [32]byte
+}
+
+type MsgConnected struct {
+	// interface name
+	Name [32]byte
+}
+
+type MsgDisconnect struct {
+	Code   uint32
+	String [96]byte
+}
+
+/* DESCRIPTOR BEGIN */
+
+const descSize = 16
+
+// desc field offsets
+const descFlagsOffset = 0
+const descRegionOffset = 2
+const descLengthOffset = 4
+const descOffsetOffset = 8
+const descMetadataOffset = 12
+
+// descBuf represents a memif descriptor as array of bytes
+type descBuf []byte
+
+// newDescBuf returns new descriptor buffer
+func newDescBuf() descBuf {
+	return make(descBuf, descSize)
+}
+
+// getDescBuff copies descriptor from shared memory to descBuf
+func (q *Queue) getDescBuf(slot int, db descBuf) {
+	copy(db, q.i.regions[q.ring.region].data[q.ring.offset+ringSize+slot*descSize:])
+}
+
+// putDescBuf copies contents of descriptor buffer into shared memory
+func (q *Queue) putDescBuf(slot int, db descBuf) {
+	copy(q.i.regions[q.ring.region].data[q.ring.offset+ringSize+slot*descSize:], db)
+}
+
+func (db descBuf) getFlags() int {
+	return (int)(binary.LittleEndian.Uint16((db)[descFlagsOffset:]))
+}
+
+func (db descBuf) getRegion() int {
+	return (int)(binary.LittleEndian.Uint16((db)[descRegionOffset:]))
+}
+
+func (db descBuf) getLength() int {
+	return (int)(binary.LittleEndian.Uint32((db)[descLengthOffset:]))
+}
+
+func (db descBuf) getOffset() int {
+	return (int)(binary.LittleEndian.Uint32((db)[descOffsetOffset:]))
+}
+
+func (db descBuf) getMetadata() int {
+	return (int)(binary.LittleEndian.Uint32((db)[descMetadataOffset:]))
+}
+
+func (db descBuf) setFlags(val int) {
+	binary.LittleEndian.PutUint16((db)[descFlagsOffset:], uint16(val))
+}
+
+func (db descBuf) setRegion(val int) {
+	binary.LittleEndian.PutUint16((db)[descRegionOffset:], uint16(val))
+}
+
+func (db descBuf) setLength(val int) {
+	binary.LittleEndian.PutUint32((db)[descLengthOffset:], uint32(val))
+}
+
+func (db descBuf) setOffset(val int) {
+	binary.LittleEndian.PutUint32((db)[descOffsetOffset:], uint32(val))
+}
+
+func (db descBuf) setMetadata(val int) {
+	binary.LittleEndian.PutUint32((db)[descMetadataOffset:], uint32(val))
+}
+
+/* DESCRIPTOR END */
+
+/* RING BEGIN */
+
+type ringType uint8
+
+const (
+	ringTypeS2M ringType = iota
+	ringTypeM2S
+)
+
+const ringSize = 128
+
+// ring field offsets
+const ringCookieOffset = 0
+const ringFlagsOffset = 4
+const ringHeadOffset = 6
+const ringTailOffset = 64
+
+// ringBuf represents a memif ring as array of bytes
+type ringBuf []byte
+
+type ring struct {
+	ringType ringType
+	size     int
+	log2Size int
+	region   int
+	rb       ringBuf
+	offset   int
+}
+
+// newRing returns new memif ring based on data received in msgAddRing (master only)
+func newRing(regionIndex int, ringType ringType, ringOffset int, log2RingSize int) *ring {
+	r := &ring{
+		ringType: ringType,
+		size:     (1 << log2RingSize),
+		log2Size: log2RingSize,
+		rb:       make(ringBuf, ringSize),
+		offset:   ringOffset,
+	}
+
+	return r
+}
+
+// newRing returns a new memif ring
+func (i *Interface) newRing(regionIndex int, ringType ringType, ringIndex int) *ring {
+	r := &ring{
+		ringType: ringType,
+		size:     (1 << i.run.Log2RingSize),
+		log2Size: int(i.run.Log2RingSize),
+		rb:       make(ringBuf, ringSize),
+	}
+
+	rSize := ringSize + descSize*r.size
+	if r.ringType == ringTypeS2M {
+		r.offset = 0
+	} else {
+		r.offset = int(i.run.NumQueuePairs) * rSize
+	}
+	r.offset += ringIndex * rSize
+
+	return r
+}
+
+// putRing put the ring to the shared memory
+func (q *Queue) putRing() {
+	copy(q.i.regions[q.ring.region].data[q.ring.offset:], q.ring.rb)
+}
+
+// updateRing updates ring with data from shared memory
+func (q *Queue) updateRing() {
+	copy(q.ring.rb, q.i.regions[q.ring.region].data[q.ring.offset:])
+}
+
+func (r *ring) getCookie() int {
+	return (int)(binary.LittleEndian.Uint32((r.rb)[ringCookieOffset:]))
+}
+
+// getFlags returns the flags value from ring buffer
+// Use Queue.getFlags in fast-path to avoid updating the whole ring.
+func (r *ring) getFlags() int {
+	return (int)(binary.LittleEndian.Uint16((r.rb)[ringFlagsOffset:]))
+}
+
+// getHead returns the head pointer value from ring buffer.
+// Use readHead in fast-path to avoid updating the whole ring.
+func (r *ring) getHead() int {
+	return (int)(binary.LittleEndian.Uint16((r.rb)[ringHeadOffset:]))
+}
+
+// getTail returns the tail pointer value from ring buffer.
+// Use readTail in fast-path to avoid updating the whole ring.
+func (r *ring) getTail() int {
+	return (int)(binary.LittleEndian.Uint16((r.rb)[ringTailOffset:]))
+}
+
+func (r *ring) setCookie(val int) {
+	binary.LittleEndian.PutUint32((r.rb)[ringCookieOffset:], uint32(val))
+}
+
+func (r *ring) setFlags(val int) {
+	binary.LittleEndian.PutUint16((r.rb)[ringFlagsOffset:], uint16(val))
+}
+
+// setHead set the head pointer value int the ring buffer.
+// Use writeHead in fast-path to avoid putting the whole ring into shared memory.
+func (r *ring) setHead(val int) {
+	binary.LittleEndian.PutUint16((r.rb)[ringHeadOffset:], uint16(val))
+}
+
+// setTail set the tail pointer value int the ring buffer.
+// Use writeTail in fast-path to avoid putting the whole ring into shared memory.
+func (r *ring) setTail(val int) {
+	binary.LittleEndian.PutUint16((r.rb)[ringTailOffset:], uint16(val))
+}
+
+/* RING END */
+
+// isInterrupt returns true if the queue is in interrupt mode
+func (q *Queue) isInterrupt() bool {
+	return (q.getFlags() & ringFlagInterrupt) == 0
+}
+
+// interrupt performs an interrupt if the queue is in interrupt mode
+func (q *Queue) interrupt() error {
+	if q.isInterrupt() {
+		buf := make([]byte, 8)
+		binary.PutUvarint(buf, 1)
+		n, err := syscall.Write(q.interruptFd, buf[:])
+		if err != nil {
+			return err
+		}
+		if n != 8 {
+			return fmt.Errorf("Faild to write to eventfd")
+		}
+	}
+
+	return nil
+}