+/* Copyright (c) 2008 The Board of Trustees of The Leland Stanford
+ * Junior University
+ *
+ * We are making the OpenFlow specification and associated documentation
+ * (Software) available for public use and benefit with the expectation
+ * that others will use, modify and enhance the Software and contribute
+ * those enhancements back to the community. However, since we would
+ * like to make the Software available for broadest use, with as few
+ * restrictions as possible permission is hereby granted, free of
+ * charge, to any person obtaining a copy of this Software to deal in
+ * the Software under the copyrights without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * The name and trademarks of copyright holder(s) may NOT be used in
+ * advertising or publicity pertaining to the Software or any
+ * derivatives without specific, written prior permission.
+ */
+
+#ifndef VCONN_PROVIDER_H
+#define VCONN_PROVIDER_H 1
+
+/* Provider interface, which provide a virtual connection to an OpenFlow
+ * device. */
+
+#include "vconn.h"
+
+/* Virtual connection to an OpenFlow device. */
+struct vconn {
+ struct vconn_class *class;
+ int connect_status;
+ uint32_t ip;
+ char *name;
+};
+
+void vconn_init(struct vconn *, struct vconn_class *, int connect_status,
+ uint32_t ip, const char *name);
+
+struct vconn_class {
+ /* Prefix for connection names, e.g. "nl", "tcp". */
+ const char *name;
+
+ /* Attempts to connect to an OpenFlow device. 'name' is the full
+ * connection name provided by the user, e.g. "nl:0", "tcp:1.2.3.4". This
+ * name is useful for error messages but must not be modified.
+ *
+ * 'suffix' is a copy of 'name' following the colon and may be modified.
+ *
+ * Returns 0 if successful, otherwise a positive errno value. If
+ * successful, stores a pointer to the new connection in '*vconnp'.
+ *
+ * The open function must not block waiting for a connection to complete.
+ * If the connection cannot be completed immediately, it should return
+ * EAGAIN (not EINPROGRESS, as returned by the connect system call) and
+ * continue the connection in the background. */
+ int (*open)(const char *name, char *suffix, struct vconn **vconnp);
+
+ /* Closes 'vconn' and frees associated memory. */
+ void (*close)(struct vconn *vconn);
+
+ /* Tries to complete the connection on 'vconn', which must be an active
+ * vconn. If 'vconn''s connection is complete, returns 0 if the connection
+ * was successful or a positive errno value if it failed. If the
+ * connection is still in progress, returns EAGAIN.
+ *
+ * The connect function must not block waiting for the connection to
+ * complete; instead, it should return EAGAIN immediately. */
+ int (*connect)(struct vconn *vconn);
+
+ /* Tries to accept a new connection on 'vconn', which must be a passive
+ * vconn. If successful, stores the new connection in '*new_vconnp' and
+ * returns 0. Otherwise, returns a positive errno value.
+ *
+ * The accept function must not block waiting for a connection. If no
+ * connection is ready to be accepted, it should return EAGAIN.
+ *
+ * Nonnull iff this is a passive vconn (one that accepts connections and
+ * does not transfer data). */
+ int (*accept)(struct vconn *vconn, struct vconn **new_vconnp);
+
+ /* Tries to receive an OpenFlow message from 'vconn', which must be an
+ * active vconn. If successful, stores the received message into '*msgp'
+ * and returns 0. The caller is responsible for destroying the message
+ * with buffer_delete(). On failure, returns a positive errno value and
+ * stores a null pointer into '*msgp'.
+ *
+ * If the connection has been closed in the normal fashion, returns EOF.
+ *
+ * The recv function must not block waiting for a packet to arrive. If no
+ * packets have been received, it should return EAGAIN.
+ *
+ * Nonnull iff this is an active vconn (one that transfers data and does
+ * not accept connections). */
+ int (*recv)(struct vconn *vconn, struct buffer **msgp);
+
+ /* Tries to queue 'msg' for transmission on 'vconn', which must be an
+ * active vconn. If successful, returns 0, in which case ownership of
+ * 'msg' is transferred to the vconn. Success does not guarantee that
+ * 'msg' has been or ever will be delivered to the peer, only that it has
+ * been queued for transmission.
+ *
+ * Returns a positive errno value on failure, in which case the caller
+ * retains ownership of 'msg'.
+ *
+ * The send function must not block. If 'msg' cannot be immediately
+ * accepted for transmission, it should return EAGAIN.
+ *
+ * Nonnull iff this is an active vconn (one that transfers data and does
+ * not accept connections). */
+ int (*send)(struct vconn *vconn, struct buffer *msg);
+
+ void (*wait)(struct vconn *vconn, enum vconn_wait_type);
+};
+
+#endif /* vconn-provider.h */