Helper functions for processing data streams in libvirtd

Defines the extensions to the remote protocol for generic
data streams. Adds a bunch of helper code to the libvirtd
daemon for working with data streams.

* daemon/Makefile.am: Add stream.c/stream.h to build
* daemon/stream.c, qemud/stream.h: Generic helper functions for
  creating new streams, associating streams with clients, finding
  existing streams for a client and removing/deleting streams.
* src/remote/remote_protocol.x: Add a new 'REMOTE_STREAM' constant
  for the 'enum remote_message_type' for encoding stream data
  in wire messages. Add a new 'REMOTE_CONTINUE' constant to
  'enum remote_message_status' to indicate further data stream
  messsages are expected to follow.  Document how the
  remote_message_header is used to encode data streams
* src/remote/remote_protocol.h: Regenerate
* daemon/dispatch.c: Remove assumption that a error message
  sent to client is always type=REMOTE_REPLY. It may now
  also be type=REMOTE_STREAM. Add convenient method for
  sending outgoing stream data packets. Log and ignore
  non-filtered incoming stream packets. Add a method for
  serializing a stream error message
* daemon/dispatch.h:  Add API for serializing stream errors
  and sending stream data packets
* daemon/qemud.h: Add struct qemud_client_stream for tracking
  active data streams for clients. Tweak filter function
  operation so that it accepts a client object too.
* daemon/qemud.c: Refactor code for free'ing message objects
  which have been fully transmitted into separate method.
  Release all active streams when client shuts down. Change
  filter function to be responsible for queueing the message

daemon/libvirtd.h

@@ -129,26 +129,43 @@ struct qemud_client_message {
     unsigned int bufferLength;
     unsigned int bufferOffset;
 
-    int async : 1;
+    unsigned int async : 1;
 
     remote_message_header hdr;
 
     struct qemud_client_message *next;
 };
 
+struct qemud_client;
+
 /* Allow for filtering of incoming messages to a custom
  * dispatch processing queue, instead of client->dx.
  */
-typedef int (*qemud_client_filter_func)(struct qemud_client_message *msg, void *opaque);
+typedef int (*qemud_client_filter_func)(struct qemud_client *client,
+                                        struct qemud_client_message *msg, void *opaque);
 struct qemud_client_filter {
     qemud_client_filter_func query;
     void *opaque;
 
-    struct qemud_client_message *dx;
-
     struct qemud_client_filter *next;
 };
 
+struct qemud_client_stream {
+    virStreamPtr st;
+    int procedure;
+    int serial;
+
+    unsigned int recvEOF : 1;
+    unsigned int closed : 1;
+
+    struct qemud_client_filter filter;
+
+    struct qemud_client_message *rx;
+    int tx;
+
+    struct qemud_client_stream *next;
+};
+
 /* Stores the per-client connection state */
 struct qemud_client {
     virMutex lock;
@@ -197,6 +214,10 @@ struct qemud_client {
      * end up on the 'dx' queue */
     struct qemud_client_filter *filters;
 
+    /* Data streams */
+    struct qemud_client_stream *streams;
+
+
     /* This is only valid if a remote open call has been made on this
      * connection, otherwise it will be NULL.  Also if remote close is
      * called, it will be set back to NULL if that succeeds.
@@ -275,6 +296,9 @@ qemudClientMessageQueuePush(struct qemud_client_message **queue,
 struct qemud_client_message *
 qemudClientMessageQueueServe(struct qemud_client_message **queue);
 
+void
+qemudClientMessageRelease(struct qemud_client *client,
+                          struct qemud_client_message *msg);
 
 
 #if HAVE_POLKIT