Add support for jumbo frames to libmemif

Add support for frames larger than maximum buffer size to libmemif
adapter.

Change-Id: I8b2d9fe7e05328194cd0aafd6e3ab40392ebbfed
Signed-off-by: Tomas Slusny <slusnucky@gmail.com>

3 files changed, 371 insertions, 37 deletions

diff --git a/extras/libmemif/README.md b/extras/libmemif/README.md
index 854aa96..d663fd2 100644
--- a/extras/libmemif/README.md
+++ b/extras/libmemif/README.md
@@ -146,6 +146,12 @@ through each of the 3 queues. The received packets are printed to stdout.
 
 Stop an instance of *raw-data* with an interrupt signal (^C).
 
+#### Jumbo Frames Raw data (libmemif <-> libmemif)
+
+*jumbo-frames* is simple example how to send larger and larger jumbo
+packets with libmemif adapter. This is simple copy of *raw-data* but with
+sending larger packets, so for more information read its code and documentation.
+
 #### ICMP Responder
 
 *icmp-responder* is a simple example showing how to answer APR and ICMP
diff --git a/extras/libmemif/adapter.go b/extras/libmemif/adapter.go
index a74c5cf..d5a1563 100644
--- a/extras/libmemif/adapter.go
+++ b/extras/libmemif/adapter.go
@@ -194,12 +194,20 @@ govpp_get_tx_queue_details (govpp_memif_details_t *md, int index)
 	return md->tx_queues[index];
 }
 
-// Copy packet data into the selected buffer.
+// Copy packet data into the selected buffer with splitting when necessary
 static void
-govpp_copy_packet_data(memif_buffer_t *buffers, int index, void *data, uint16_t size)
+govpp_copy_packet_data(memif_buffer_t *buffers, uint16_t allocated, int bufIndex, void *packetData, uint16_t packetSize)
 {
-	buffers[index].len = (size > buffers[index].len ? buffers[index].len : size);
-	memcpy(buffers[index].data, data, (size_t)buffers[index].len);
+	int dataOffset = 0;
+
+	do {
+		buffers[bufIndex].len = (packetSize > buffers[bufIndex].len ? buffers[bufIndex].len : packetSize);
+		void * curData = (packetData + dataOffset);
+		memcpy(buffers[bufIndex].data, curData, (size_t)buffers[bufIndex].len);
+		dataOffset += buffers[bufIndex].len;
+		bufIndex += 1;
+		packetSize -= buffers[bufIndex].len;
+	} while(packetSize > 0 && bufIndex < allocated && buffers[bufIndex].flags & MEMIF_BUFFER_FLAG_NEXT > 0);
 }
 
 // Get packet data from the selected buffer.
@@ -211,6 +219,26 @@ govpp_get_packet_data(memif_buffer_t *buffers, int index, int *size)
 	return buffers[index].data;
 }
 
+// Checks if memif buffer is chained
+static int
+govpp_is_buffer_chained(memif_buffer_t *buffers, int index)
+{
+    return buffers[index].flags & MEMIF_BUFFER_FLAG_NEXT;
+}
+
+// Allocate memif buffers and return pointer to next free buffer
+static int
+govpp_memif_buffer_alloc(memif_conn_handle_t conn, uint16_t qid,
+			memif_buffer_t * bufs, uint16_t offset, memif_buffer_t ** nextFreeBuf,
+			uint16_t count, uint16_t * count_out, uint16_t size)
+{
+    memif_buffer_t * offsetBufs = (bufs + offset);
+    int err = memif_buffer_alloc(conn, qid, offsetBufs, count, count_out, size);
+    *count_out += offset;
+    *nextFreeBuf = offsetBufs;
+    return err;
+}
+
 */
 import "C"
 
@@ -345,6 +373,7 @@ type Memif struct {
 
 	// Rx/Tx queues
 	ringSize    int              // number of items in each ring
+	bufferSize  int              // max buffer size
 	stopQPollFd int              // event file descriptor used to stop pollRxQueue-s
 	wg          sync.WaitGroup   // wait group for all pollRxQueue-s
 	rxQueueBufs []CPacketBuffers // an array of C-libmemif packet buffers for each RX queue
@@ -388,6 +417,7 @@ type MemifQueueDetails struct {
 type CPacketBuffers struct {
 	buffers *C.memif_buffer_t
 	count   int
+	rxChainBuf []RawPacketData
 }
 
 // Context is a global Go-libmemif runtime context.
@@ -400,6 +430,11 @@ type Context struct {
 	wg sync.WaitGroup /* wait-group for pollEvents() */
 }
 
+type txPacketBuffer struct {
+	packets []RawPacketData
+	size    int
+}
+
 var (
 	// logger used by the adapter.
 	log *logger.Logger
@@ -517,12 +552,18 @@ func CreateInterface(config *MemifConfig, callbacks *MemifCallbacks) (memif *Mem
 		log2RingSize = 10
 	}
 
+	bufferSize := config.BufferSize
+	if bufferSize <= 0 {
+		bufferSize = 2048
+	}
+
 	// Create memif-wrapper for Go-libmemif.
 	memif = &Memif{
-		MemifMeta: config.MemifMeta,
-		callbacks: &MemifCallbacks{},
-		ifIndex:   context.nextMemifIndex,
-		ringSize:  1 << log2RingSize,
+		MemifMeta:  config.MemifMeta,
+		callbacks:  &MemifCallbacks{},
+		ifIndex:    context.nextMemifIndex,
+		ringSize:   1 << log2RingSize,
+		bufferSize: int(bufferSize),
 	}
 
 	// Initialize memif callbacks.
@@ -717,10 +758,6 @@ func (memif *Memif) GetDetails() (details *MemifDetails, err error) {
 // Multiple TxBurst-s can run concurrently provided that each targets a different
 // TX queue.
 func (memif *Memif) TxBurst(queueID uint8, packets []RawPacketData) (count uint16, err error) {
-	var sentCount C.uint16_t
-	var allocated C.uint16_t
-	var bufSize int
-
 	if len(packets) == 0 {
 		return 0, nil
 	}
@@ -729,16 +766,55 @@ func (memif *Memif) TxBurst(queueID uint8, packets []RawPacketData) (count uint1
 		return 0, ErrQueueID
 	}
 
-	// The largest packet in the set determines the packet buffer size.
+	var bufCount int
+	var buffers []*txPacketBuffer
+	cQueueID := C.uint16_t(queueID)
+
 	for _, packet := range packets {
-		if len(packet) > int(bufSize) {
-			bufSize = len(packet)
+		packetLen := len(packet)
+		log.Debugf("%v - preparing packet with len %v", cQueueID, packetLen)
+
+		if packetLen > memif.bufferSize {
+			// Create jumbo buffer
+			buffer := &txPacketBuffer{
+				size:    packetLen,
+				packets: []RawPacketData{packet},
+			}
+
+			buffers = append(buffers, buffer)
+
+			// Increment bufCount by number of splits in this jumbo
+			bufCount += (buffer.size + memif.bufferSize - 1) / memif.bufferSize
+		} else {
+			buffersLen := len(buffers)
+
+			// This is very first buffer so there is no data to append to, prepare empty one
+			if buffersLen == 0 {
+				buffers = []*txPacketBuffer{{}}
+				buffersLen = 1
+			}
+
+			lastBuffer := buffers[buffersLen-1]
+
+			// Last buffer is jumbo buffer, create new buffer
+			if lastBuffer.size > memif.bufferSize {
+				lastBuffer = &txPacketBuffer{}
+				buffers = append(buffers, lastBuffer)
+			}
+
+			// Determine buffer size by max packet size in buffer
+			if packetLen > lastBuffer.size {
+				lastBuffer.size = packetLen
+			}
+
+			lastBuffer.packets = append(lastBuffer.packets, packet)
+			bufCount += 1
 		}
 	}
 
 	// Reallocate Tx buffers if needed to fit the input packets.
-	pb := memif.txQueueBufs[queueID]
-	bufCount := len(packets)
+	log.Debugf("%v - total buffer to allocate count %v", cQueueID, bufCount)
+	pb := &memif.txQueueBufs[queueID]
 	if pb.count < bufCount {
 		newBuffers := C.realloc(unsafe.Pointer(pb.buffers), C.size_t(bufCount*int(C.sizeof_memif_buffer_t)))
 		if newBuffers == nil {
@@ -751,32 +827,79 @@ func (memif *Memif) TxBurst(queueID uint8, packets []RawPacketData) (count uint1
 	}
 
 	// Allocate ring slots.
-	cQueueID := C.uint16_t(queueID)
-	errCode := C.memif_buffer_alloc(memif.cHandle, cQueueID, pb.buffers, C.uint16_t(bufCount),
-		&allocated, C.uint32_t(bufSize))
-	err = getMemifError(int(errCode))
-	if err == ErrNoBufRing {
-		// Not enough ring slots, <count> will be less than bufCount.
-		err = nil
-	}
-	if err != nil {
-		return 0, err
-	}
+	var allocated C.uint16_t
+	var subCount C.uint16_t
+	for _, buffer := range buffers {
+		packetCount := C.uint16_t(len(buffer.packets))
+		isJumbo := buffer.size > memif.bufferSize
+
+		log.Debugf("%v - trying to send max buff size %v, packets len %v, buffer len %v, jumbo %v",
+			cQueueID, buffer.size, len(buffer.packets), packetCount, isJumbo)
+
+		var nextFreeBuff *C.memif_buffer_t
+		startOffset := allocated
+		errCode := C.govpp_memif_buffer_alloc(memif.cHandle, cQueueID, pb.buffers, startOffset, &nextFreeBuff,
+			packetCount, &allocated, C.uint16_t(buffer.size))
+
+		err = getMemifError(int(errCode))
+		endEarly := err == ErrNoBufRing
+		if endEarly {
+			// Not enough ring slots, <count> will be less than packetCount.
+			err = nil
+		}
+		if err != nil {
+			return 0, err
+		}
+
+		// Copy packet data into the buffers.
+		nowAllocated := allocated - startOffset
+		toFill := nowAllocated
+		if !isJumbo {
+			// If this is not jumbo frame, only 1 packet needs to be copied each iteration
+			toFill = 1
+		}
+
+		// Iterate over all packets and try to fill them into allocated buffers
+		// If packet is jumbo frame, continue filling to allocated buffers until no buffer is left
+		for i, packet := range buffer.packets {
+			if i >= int(nowAllocated) {
+				// There was less allocated buffers than actual packet count so exit early
+				break
+			}
+
+			packetData := unsafe.Pointer(&packet[0])
+			C.govpp_copy_packet_data(nextFreeBuff, toFill, C.int(i), packetData, C.uint16_t(len(packet)))
+		}
+
+		if isJumbo && nowAllocated > 0 {
+			// If we successfully allocated required amount of buffers for entire jumbo to be sent
+			// simply sub entire amount of jumbo frame packets and leave only 1 so sender will think
+			// it only sent 1 packet so it does not need to know anything about jumbo frames
+			subCount += nowAllocated - 1
+		}
 
-	// Copy packet data into the buffers.
-	for i := 0; i < int(allocated); i++ {
-		packetData := unsafe.Pointer(&packets[i][0])
-		C.govpp_copy_packet_data(pb.buffers, C.int(i), packetData, C.uint16_t(len(packets[i])))
+		// If we do not have enough buffers left to allocate, simply end here to avoid packet loss and try
+		// to handle it next burst
+		if endEarly {
+			break
+		}
 	}
 
-	errCode = C.memif_tx_burst(memif.cHandle, cQueueID, pb.buffers, allocated, &sentCount)
+	var sentCount C.uint16_t
+	errCode := C.memif_tx_burst(memif.cHandle, cQueueID, pb.buffers, allocated, &sentCount)
 	err = getMemifError(int(errCode))
 	if err != nil {
 		return 0, err
 	}
-	count = uint16(sentCount)
 
-	return count, nil
+	// Prevent negative values
+	realSent := uint16(sentCount) - uint16(subCount)
+	if subCount > sentCount {
+		sentCount = 0
+	}
+
+	log.Debugf("%v - sent %v total allocated buffs %v", cQueueID, sentCount, allocated)
+	return realSent, nil
 }
 
 // RxBurst is used to receive multiple packets in one call from a selected queue.
@@ -799,7 +922,7 @@ func (memif *Memif) RxBurst(queueID uint8, count uint16) (packets []RawPacketDat
 	}
 
 	// Reallocate Rx buffers if needed to fit the output packets.
-	pb := memif.rxQueueBufs[queueID]
+	pb := &memif.rxQueueBufs[queueID]
 	bufCount := int(count)
 	if pb.count < bufCount {
 		newBuffers := C.realloc(unsafe.Pointer(pb.buffers), C.size_t(bufCount*int(C.sizeof_memif_buffer_t)))
@@ -824,11 +947,31 @@ func (memif *Memif) RxBurst(queueID uint8, count uint16) (packets []RawPacketDat
 		return packets, err
 	}
 
+	chained := len(pb.rxChainBuf) > 0
+	if chained {
+		// We had stored data from previous burst because last buffer in previous burst was chained
+		// so we need to continue appending to this data
+		packets = pb.rxChainBuf
+		pb.rxChainBuf = nil
+	}
+
 	// Copy packet data into the instances of RawPacketData.
 	for i := 0; i < int(recvCount); i++ {
 		var packetSize C.int
 		packetData := C.govpp_get_packet_data(pb.buffers, C.int(i), &packetSize)
-		packets = append(packets, C.GoBytes(packetData, packetSize))
+		packetBytes := C.GoBytes(packetData, packetSize)
+
+		if chained {
+			// We have chained buffers, so start merging packet data with last read packet
+			prevPacket := packets[len(packets)-1]
+			packets[len(packets)-1] = append(prevPacket, packetBytes...)
+		} else {
+			packets = append(packets, packetBytes)
+		}
+
+		// Mark last buffer as chained based on property on current buffer so next buffers
+		// will try to append data to this one in case we got jumbo frame
+		chained = C.govpp_is_buffer_chained(pb.buffers, C.int(i)) > 0
 	}
 
 	if recvCount > 0 {
@@ -840,6 +983,15 @@ func (memif *Memif) RxBurst(queueID uint8, count uint16) (packets []RawPacketDat
 		packets = nil
 	}
 
+	if chained {
+		// We did not had enough space to process all chained buffers to the end so simply tell
+		// reader that it should not process any packets here and save them for next burst
+		// to finish reading the buffer chain
+		pb.rxChainBuf = packets
+		packets = nil
+		err = ErrNoBuf
+	}
+
 	return packets, err
 }
 
diff --git a/extras/libmemif/examples/jumbo-frames/jumbo-frames.go b/extras/libmemif/examples/jumbo-frames/jumbo-frames.go
new file mode 100644
index 0000000..1bc943f
--- /dev/null
+++ b/extras/libmemif/examples/jumbo-frames/jumbo-frames.go
@@ -0,0 +1,176 @@
+// jumbo-frames is simple example how to send larger and larger jumbo packets with libmemif adapter. This is simple copy
+// of raw-data but with sending larger packets, so for more information read its code and docs.
+package main
+
+import (
+	"fmt"
+	"os"
+	"os/signal"
+	"sync"
+	"time"
+
+	"git.fd.io/govpp.git/extras/libmemif"
+)
+
+const (
+	Socket             = "/tmp/jumbo-frames-example"
+	Secret             = "secret"
+	ConnectionID       = 1
+	NumQueues    uint8 = 3
+)
+
+var wg sync.WaitGroup
+var stopCh chan struct{}
+
+func OnConnect(memif *libmemif.Memif) (err error) {
+	details, err := memif.GetDetails()
+	if err != nil {
+		fmt.Printf("libmemif.GetDetails() error: %v\n", err)
+	}
+	fmt.Printf("memif %s has been connected: %+v\n", memif.IfName, details)
+
+	stopCh = make(chan struct{})
+	var i uint8
+	for i = 0; i < uint8(len(details.RxQueues)); i++ {
+		wg.Add(1)
+		go ReadAndPrintPackets(memif, i)
+	}
+	for i = 0; i < uint8(len(details.TxQueues)); i++ {
+		wg.Add(1)
+		go SendPackets(memif, i)
+	}
+	return nil
+}
+
+func OnDisconnect(memif *libmemif.Memif) (err error) {
+	fmt.Printf("memif %s has been disconnected\n", memif.IfName)
+	close(stopCh)
+	wg.Wait()
+	return nil
+}
+
+func ReadAndPrintPackets(memif *libmemif.Memif, queueID uint8) {
+	defer wg.Done()
+
+	interruptCh, err := memif.GetQueueInterruptChan(queueID)
+	if err != nil {
+		switch err {
+		case libmemif.ErrQueueID:
+			fmt.Printf("libmemif.Memif.GetQueueInterruptChan() complains about invalid queue id!?")
+		default:
+			fmt.Printf("libmemif.Memif.GetQueueInterruptChan() error: %v\n", err)
+		}
+		return
+	}
+
+	counter := 0
+	for {
+		select {
+		case <-interruptCh:
+			counter++
+			for {
+				packets, err := memif.RxBurst(queueID, 10)
+				if err != nil {
+					fmt.Printf("libmemif.Memif.RxBurst() error: %v\n", err)
+				} else {
+					if len(packets) == 0 {
+						break
+					}
+					for _, packet := range packets {
+						fmt.Printf("Received packet queue=%d: %v in burst %d\n", queueID, len(packet), counter)
+					}
+				}
+			}
+		case <-stopCh:
+			return
+		}
+	}
+}
+
+func SendPackets(memif *libmemif.Memif, queueID uint8) {
+	defer wg.Done()
+
+	counter := 0
+	for {
+		select {
+		case <-time.After(3 * time.Second):
+			counter++
+			packetMul :=  counter % 100 + 1 // Limit max iterations to 100 to not go out of bounds
+			packets := []libmemif.RawPacketData{
+				make([]byte, 128*packetMul),
+				make([]byte, 256*packetMul),
+				make([]byte, 512*packetMul),
+			}
+			sent := 0
+			for {
+				count, err := memif.TxBurst(queueID, packets[sent:])
+				if err != nil {
+					fmt.Printf("libmemif.Memif.TxBurst() error: %v\n", err)
+					break
+				} else {
+					fmt.Printf("libmemif.Memif.TxBurst() has sent %d packets in burst %v.\n", count, counter)
+					sent += int(count)
+					if sent == len(packets) {
+						break
+					}
+				}
+			}
+		case <-stopCh:
+			return
+		}
+	}
+}
+
+func main() {
+	var isMaster = true
+	var appSuffix string
+	if len(os.Args) > 1 && (os.Args[1] == "--slave" || os.Args[1] == "-slave") {
+		isMaster = false
+		appSuffix = "-slave"
+	}
+
+	appName := "jumbo-frames" + appSuffix
+	fmt.Println("Initializing libmemif as ", appName)
+	err := libmemif.Init(appName)
+	if err != nil {
+		fmt.Printf("libmemif.Init() error: %v\n", err)
+		return
+	}
+	defer libmemif.Cleanup()
+
+	memifCallbacks := &libmemif.MemifCallbacks{
+		OnConnect:    OnConnect,
+		OnDisconnect: OnDisconnect,
+	}
+
+	memifConfig := &libmemif.MemifConfig{
+		MemifMeta: libmemif.MemifMeta{
+			IfName:         "memif1",
+			ConnID:         ConnectionID,
+			SocketFilename: Socket,
+			Secret:         Secret,
+			IsMaster:       isMaster,
+			Mode:           libmemif.IfModeEthernet,
+		},
+		MemifShmSpecs: libmemif.MemifShmSpecs{
+			NumRxQueues:  NumQueues,
+			NumTxQueues:  NumQueues,
+			BufferSize:   2048,
+			Log2RingSize: 10,
+		},
+	}
+
+	fmt.Printf("Callbacks: %+v\n", memifCallbacks)
+	fmt.Printf("Config: %+v\n", memifConfig)
+
+	memif, err := libmemif.CreateInterface(memifConfig, memifCallbacks)
+	if err != nil {
+		fmt.Printf("libmemif.CreateInterface() error: %v\n", err)
+		return
+	}
+	defer memif.Close()
+
+	sigChan := make(chan os.Signal, 1)
+	signal.Notify(sigChan, os.Interrupt)
+	<-sigChan
+}