/* 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 to vconns, which provide a virtual connection to an
 * OpenFlow device. */

#include <assert.h>
#include "vconn.h"

/* Active virtual connection to an OpenFlow device. */

/* Active virtual connection to an OpenFlow device.
 *
 * This structure should be treated as opaque by vconn implementations. */
struct vconn {
    struct vconn_class *class;
    int state;
    int error;
    int min_version;
    int version;
    uint32_t ip;
    char *name;
};

void vconn_init(struct vconn *, struct vconn_class *, int connect_status,
                uint32_t ip, const char *name);
static inline void vconn_assert_class(const struct vconn *vconn,
                                      const struct vconn_class *class)
{
    assert(vconn->class == class);
}

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'.  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 receive an OpenFlow message from 'vconn'.  If successful,
     * stores the received message into '*msgp' and returns 0.  The caller is
     * responsible for destroying the message with ofpbuf_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. */
    int (*recv)(struct vconn *vconn, struct ofpbuf **msgp);

    /* Tries to queue 'msg' for transmission on '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. */
    int (*send)(struct vconn *vconn, struct ofpbuf *msg);

    /* Arranges for the poll loop to wake up when 'vconn' is ready to take an
     * action of the given 'type'. */
    void (*wait)(struct vconn *vconn, enum vconn_wait_type type);
};

/* Passive virtual connection to an OpenFlow device.
 *
 * This structure should be treated as opaque by vconn implementations. */
struct pvconn {
    struct pvconn_class *class;
    char *name;
};

void pvconn_init(struct pvconn *, struct pvconn_class *, const char *name);
static inline void pvconn_assert_class(const struct pvconn *pvconn,
                                       const struct pvconn_class *class)
{
    assert(pvconn->class == class);
}

struct pvconn_class {
    /* Prefix for connection names, e.g. "ptcp", "pssl". */
    const char *name;

    /* Attempts to start listening for OpenFlow connections.  '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 '*pvconnp'.
     *
     * The listen function must not block.  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 (*listen)(const char *name, char *suffix, struct pvconn **pvconnp);

    /* Closes 'pvconn' and frees associated memory. */
    void (*close)(struct pvconn *pvconn);

    /* Tries to accept a new connection on 'pvconn'.  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. */
    int (*accept)(struct pvconn *pvconn, struct vconn **new_vconnp);

    /* Arranges for the poll loop to wake up when a connection is ready to be
     * accepted on 'pvconn'. */
    void (*wait)(struct pvconn *pvconn);
};

/* Active and passive vconn classes. */
extern struct vconn_class tcp_vconn_class;
extern struct pvconn_class ptcp_pvconn_class;
extern struct vconn_class unix_vconn_class;
extern struct pvconn_class punix_pvconn_class;
#ifdef HAVE_OPENSSL
extern struct vconn_class ssl_vconn_class;
extern struct pvconn_class pssl_pvconn_class;
#endif
#ifdef HAVE_NETLINK
extern struct vconn_class netlink_vconn_class;
#endif

#endif /* vconn-provider.h */