haproxy/include/proto/protocols.h

/*
  include/proto/protocols.h
  This file declares generic protocol primitives.

  Copyright (C) 2000-2007 Willy Tarreau - w@1wt.eu
  
  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation, version 2.1
  exclusively.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
*/

#ifndef _PROTO_PROTOCOLS_H
#define _PROTO_PROTOCOLS_H

#include <types/protocols.h>

/* This function adds the specified listener's file descriptor to the polling
 * lists if it is in the LI_LISTEN state. The listener enters LI_READY or
 * LI_FULL state depending on its number of connections.
 */
void enable_listener(struct listener *listener);

/* This function removes the specified listener's file descriptor from the
 * polling lists if it is in the LI_READY or in the LI_FULL state. The listener
 * enters LI_LISTEN.
 */
void disable_listener(struct listener *listener);

/* This function tries to temporarily disable a listener, depending on the OS
 * capabilities. Linux unbinds the listen socket after a SHUT_RD, and ignores
 * SHUT_WR. Solaris refuses either shutdown(). OpenBSD ignores SHUT_RD but
 * closes upon SHUT_WR and refuses to rebind. So a common validation path
 * involves SHUT_WR && listen && SHUT_RD. In case of success, the FD's polling
 * is disabled. It normally returns non-zero, unless an error is reported.
 */
int pause_listener(struct listener *l);

/* This function tries to resume a temporarily disabled listener.
 * The resulting state will either be LI_READY or LI_FULL. 0 is returned
 * in case of failure to resume (eg: dead socket).
 */
int resume_listener(struct listener *l);

/* Marks a ready listener as full so that the session code tries to re-enable
 * it upon next close() using resume_listener().
 */
void listener_full(struct listener *l);

/* This function adds all of the protocol's listener's file descriptors to the
 * polling lists when they are in the LI_LISTEN state. It is intended to be
 * used as a protocol's generic enable_all() primitive, for use after the
 * fork(). It puts the listeners into LI_READY or LI_FULL states depending on
 * their number of connections. It always returns ERR_NONE.
 */
int enable_all_listeners(struct protocol *proto);

/* This function removes all of the protocol's listener's file descriptors from
 * the polling lists when they are in the LI_READY or LI_FULL states. It is
 * intended to be used as a protocol's generic disable_all() primitive. It puts
 * the listeners into LI_LISTEN, and always returns ERR_NONE.
 */
int disable_all_listeners(struct protocol *proto);

/* Marks a ready listener as limited so that we only try to re-enable it when
 * resources are free again. It will be queued into the specified queue.
 */
void limit_listener(struct listener *l, struct list *list);

/* Dequeues all of the listeners waiting for a resource in wait queue <queue>. */
void dequeue_all_listeners(struct list *list);

/* This function closes the listening socket for the specified listener,
 * provided that it's already in a listening state. The listener enters the
 * LI_ASSIGNED state. It always returns ERR_NONE. This function is intended
 * to be used as a generic function for standard protocols.
 */
int unbind_listener(struct listener *listener);

/* This function closes all listening sockets bound to the protocol <proto>,
 * and the listeners end in LI_ASSIGNED state if they were higher. It does not
 * detach them from the protocol. It always returns ERR_NONE.
 */
int unbind_all_listeners(struct protocol *proto);

/* Delete a listener from its protocol's list of listeners. The listener's
 * state is automatically updated from LI_ASSIGNED to LI_INIT. The protocol's
 * number of listeners is updated. Note that the listener must have previously
 * been unbound. This is the generic function to use to remove a listener.
 */
void delete_listener(struct listener *listener);

/* This function is called on a read event from a listening socket, corresponding
 * to an accept. It tries to accept as many connections as possible, and for each
 * calls the listener's accept handler (generally the frontend's accept handler).
 */
int listener_accept(int fd);

/* Registers the protocol <proto> */
void protocol_register(struct protocol *proto);

/* Unregisters the protocol <proto>. Note that all listeners must have
 * previously been unbound.
 */
void protocol_unregister(struct protocol *proto);

/* binds all listeneres of all registered protocols. Returns a composition
 * of ERR_NONE, ERR_RETRYABLE, ERR_FATAL.
 */
int protocol_bind_all(char *errmsg, int errlen);

/* unbinds all listeners of all registered protocols. They are also closed.
 * This must be performed before calling exit() in order to get a chance to
 * remove file-system based sockets and pipes.
 * Returns a composition of ERR_NONE, ERR_RETRYABLE, ERR_FATAL.
 */
int protocol_unbind_all(void);

/* enables all listeners of all registered protocols. This is intended to be
 * used after a fork() to enable reading on all file descriptors. Returns a
 * composition of ERR_NONE, ERR_RETRYABLE, ERR_FATAL.
 */
int protocol_enable_all(void);

/* returns the protocol associated to family <family> or NULL if not found */
struct protocol *protocol_by_family(int family);

#endif /* _PROTO_PROTOCOLS_H */

/*
 * Local variables:
 *  c-indent-level: 8
 *  c-basic-offset: 8
 * End:
 */