gomemif: introduce gomemif

golang native memif driver

Type: feature

Signed-off-by: Jakub Grajciar <jgrajcia@cisco.com>
Change-Id: I693156a44011c80025245d25134f5bf5db6eba82
Signed-off-by: Jakub Grajciar <jgrajcia@cisco.com>

1 files changed, 60 insertions, 0 deletions

diff --git a/extras/gomemif/memif/control_channel_unsafe.go b/extras/gomemif/memif/control_channel_unsafe.go
new file mode 100644
index 00000000000..9e91297b160
--- /dev/null
+++ b/extras/gomemif/memif/control_channel_unsafe.go
@@ -0,0 +1,60 @@
+/*
+ *------------------------------------------------------------------
+ * 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 (
+	"fmt"
+	"os"
+	"syscall"
+	"unsafe"
+)
+
+// sendMsg sends a control message from contorl channels message queue
+func (cc *controlChannel) sendMsg() (err error) {
+	if len(cc.msgQueue) < 1 {
+		return nil
+	}
+	// Get message buffer
+	msg := cc.msgQueue[0]
+	// Dequeue
+	cc.msgQueue = cc.msgQueue[1:]
+
+	iov := &syscall.Iovec{
+		Base: &msg.Buffer.Bytes()[0],
+		Len:  msgSize,
+	}
+
+	msgh := syscall.Msghdr{
+		Iov:    iov,
+		Iovlen: 1,
+	}
+
+	if msg.Fd > 0 {
+		oob := syscall.UnixRights(msg.Fd)
+		msgh.Control = &oob[0]
+		msgh.Controllen = uint64(syscall.CmsgSpace(4))
+	}
+
+	_, _, errno := syscall.Syscall(syscall.SYS_SENDMSG, uintptr(cc.event.Fd), uintptr(unsafe.Pointer(&msgh)), uintptr(0))
+	if errno != 0 {
+		err = os.NewSyscallError("sendmsg", errno)
+		return fmt.Errorf("SYS_SENDMSG: %s", errno)
+	}
+
+	return nil
+}