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-rw-r--r--extras/gomemif/memif/packet_writer.go95
1 files changed, 95 insertions, 0 deletions
diff --git a/extras/gomemif/memif/packet_writer.go b/extras/gomemif/memif/packet_writer.go
new file mode 100644
index 00000000000..702044f4b49
--- /dev/null
+++ b/extras/gomemif/memif/packet_writer.go
@@ -0,0 +1,95 @@
+/*
+ *------------------------------------------------------------------
+ * 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
+
+// WritePacket writes one packet to the shared memory and
+// returns the number of bytes written
+func (q *Queue) WritePacket(pkt []byte) int {
+ var mask int = q.ring.size - 1
+ var slot int
+ var nFree uint16
+ var packetBufferSize int = int(q.i.run.PacketBufferSize)
+
+ if q.i.args.IsMaster {
+ slot = q.readTail()
+ nFree = uint16(q.readHead() - slot)
+ } else {
+ slot = q.readHead()
+ nFree = uint16(q.ring.size - slot + q.readTail())
+ }
+
+ if nFree == 0 {
+ q.interrupt()
+ return 0
+ }
+
+ // copy descriptor from shm
+ desc := newDescBuf()
+ q.getDescBuf(slot&mask, desc)
+ // reset flags
+ desc.setFlags(0)
+ // reset length
+ if q.i.args.IsMaster {
+ packetBufferSize = desc.getLength()
+ }
+ desc.setLength(0)
+ offset := desc.getOffset()
+
+ // write packet into memif buffer
+ n := copy(q.i.regions[desc.getRegion()].data[offset:offset+packetBufferSize], pkt[:])
+ desc.setLength(n)
+ for n < len(pkt) {
+ nFree--
+ if nFree == 0 {
+ q.interrupt()
+ return 0
+ }
+ desc.setFlags(descFlagNext)
+ q.putDescBuf(slot&mask, desc)
+ slot++
+
+ // copy descriptor from shm
+ q.getDescBuf(slot&mask, desc)
+ // reset flags
+ desc.setFlags(0)
+ // reset length
+ if q.i.args.IsMaster {
+ packetBufferSize = desc.getLength()
+ }
+ desc.setLength(0)
+ offset := desc.getOffset()
+
+ tmp := copy(q.i.regions[desc.getRegion()].data[offset:offset+packetBufferSize], pkt[:])
+ desc.setLength(tmp)
+ n += tmp
+ }
+
+ // copy descriptor to shm
+ q.putDescBuf(slot&mask, desc)
+ slot++
+
+ if q.i.args.IsMaster {
+ q.writeTail(slot)
+ } else {
+ q.writeHead(slot)
+ }
+
+ q.interrupt()
+
+ return n
+}