Refactor faasd and faas-containerd merge

The use of containerd and CNI functions has been refactored to reuse
the same codebase.

Added all network functionality to own directory and package. Removed
netlink and weave library in favor of using CNI plugin result files.

Rename containers handler to functions to clear-up functionality.

Signed-off-by: Carlos de Paula <me@carlosedp.com>

vendor/github.com/vishvananda/netlink/nl/nl_linux.go

@@ -21,7 +21,13 @@ const (
 	FAMILY_ALL  = unix.AF_UNSPEC
 	FAMILY_V4   = unix.AF_INET
 	FAMILY_V6   = unix.AF_INET6
-	FAMILY_MPLS = AF_MPLS
+	FAMILY_MPLS = unix.AF_MPLS
+	// Arbitrary set value (greater than default 4k) to allow receiving
+	// from kernel more verbose messages e.g. for statistics,
+	// tc rules or filters, or other more memory requiring data.
+	RECEIVE_BUFFER_SIZE = 65536
+	// Kernel netlink pid
+	PidKernel uint32 = 0
 )
 
 // SupportedNlFamilies contains the list of netlink families this netlink package supports
@@ -42,7 +48,7 @@ func GetIPFamily(ip net.IP) int {
 
 var nativeEndian binary.ByteOrder
 
-// Get native endianness for the system
+// NativeEndian gets native endianness for the system
 func NativeEndian() binary.ByteOrder {
 	if nativeEndian == nil {
 		var x uint32 = 0x01020304
@@ -271,15 +277,22 @@ func NewRtAttr(attrType int, data []byte) *RtAttr {
 	}
 }
 
-// Create a new RtAttr obj anc add it as a child of an existing object
+// NewRtAttrChild adds an RtAttr as a child to the parent and returns the new attribute
+//
+// Deprecated: Use AddRtAttr() on the parent object
 func NewRtAttrChild(parent *RtAttr, attrType int, data []byte) *RtAttr {
+	return parent.AddRtAttr(attrType, data)
+}
+
+// AddRtAttr adds an RtAttr as a child and returns the new attribute
+func (a *RtAttr) AddRtAttr(attrType int, data []byte) *RtAttr {
 	attr := NewRtAttr(attrType, data)
-	parent.children = append(parent.children, attr)
+	a.children = append(a.children, attr)
 	return attr
 }
 
-// AddChild adds an existing RtAttr as a child.
-func (a *RtAttr) AddChild(attr *RtAttr) {
+// AddChild adds an existing NetlinkRequestData as a child.
+func (a *RtAttr) AddChild(attr NetlinkRequestData) {
 	a.children = append(a.children, attr)
 }
 
@@ -360,16 +373,12 @@ func (req *NetlinkRequest) Serialize() []byte {
 }
 
 func (req *NetlinkRequest) AddData(data NetlinkRequestData) {
-	if data != nil {
-		req.Data = append(req.Data, data)
-	}
+	req.Data = append(req.Data, data)
 }
 
 // AddRawData adds raw bytes to the end of the NetlinkRequest object during serialization
 func (req *NetlinkRequest) AddRawData(data []byte) {
-	if data != nil {
-		req.RawData = append(req.RawData, data...)
-	}
+	req.RawData = append(req.RawData, data...)
 }
 
 // Execute the request against a the given sockType.
@@ -413,10 +422,13 @@ func (req *NetlinkRequest) Execute(sockType int, resType uint16) ([][]byte, erro
 
 done:
 	for {
-		msgs, err := s.Receive()
+		msgs, from, err := s.Receive()
 		if err != nil {
 			return nil, err
 		}
+		if from.Pid != PidKernel {
+			return nil, fmt.Errorf("Wrong sender portid %d, expected %d", from.Pid, PidKernel)
+		}
 		for _, m := range msgs {
 			if m.Header.Seq != req.Seq {
 				if sharedSocket {
@@ -425,7 +437,7 @@ done:
 				return nil, fmt.Errorf("Wrong Seq nr %d, expected %d", m.Header.Seq, req.Seq)
 			}
 			if m.Header.Pid != pid {
-				return nil, fmt.Errorf("Wrong pid %d, expected %d", m.Header.Pid, pid)
+				continue
 			}
 			if m.Header.Type == unix.NLMSG_DONE {
 				break done
@@ -610,21 +622,31 @@ func (s *NetlinkSocket) Send(request *NetlinkRequest) error {
 	return nil
 }
 
-func (s *NetlinkSocket) Receive() ([]syscall.NetlinkMessage, error) {
+func (s *NetlinkSocket) Receive() ([]syscall.NetlinkMessage, *unix.SockaddrNetlink, error) {
 	fd := int(atomic.LoadInt32(&s.fd))
 	if fd < 0 {
-		return nil, fmt.Errorf("Receive called on a closed socket")
+		return nil, nil, fmt.Errorf("Receive called on a closed socket")
 	}
-	rb := make([]byte, unix.Getpagesize())
-	nr, _, err := unix.Recvfrom(fd, rb, 0)
+	var fromAddr *unix.SockaddrNetlink
+	var rb [RECEIVE_BUFFER_SIZE]byte
+	nr, from, err := unix.Recvfrom(fd, rb[:], 0)
 	if err != nil {
-		return nil, err
+		return nil, nil, err
+	}
+	fromAddr, ok := from.(*unix.SockaddrNetlink)
+	if !ok {
+		return nil, nil, fmt.Errorf("Error converting to netlink sockaddr")
 	}
 	if nr < unix.NLMSG_HDRLEN {
-		return nil, fmt.Errorf("Got short response from netlink")
+		return nil, nil, fmt.Errorf("Got short response from netlink")
 	}
-	rb = rb[:nr]
-	return syscall.ParseNetlinkMessage(rb)
+	rb2 := make([]byte, nr)
+	copy(rb2, rb[:nr])
+	nl, err := syscall.ParseNetlinkMessage(rb2)
+	if err != nil {
+		return nil, nil, err
+	}
+	return nl, fromAddr, nil
 }
 
 // SetSendTimeout allows to set a send timeout on the socket