5bcae64538
Rwsplit handles ERRACT_NEW_CONNECTION by clearing backend reference, removing callbacks and associating backend reference with new backend server. If it succeeds and the router session can continue, handleError returns true. Otherwise false. When ever false is returned it means that session must be closed. Rwsplit now tolerates backend failures in a way that it searches new backends when monitor, backend, or client operation fails due to backend failure.
150 lines
4.5 KiB
C
150 lines
4.5 KiB
C
#ifndef _SESSION_H
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#define _SESSION_H
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/*
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* This file is distributed as part of the SkySQL Gateway. It is free
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* software: you can redistribute it and/or modify it under the terms of the
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* GNU General Public License as published by the Free Software Foundation,
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* version 2.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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* details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc., 51
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* Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Copyright SkySQL Ab 2013
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*/
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/**
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* @file session.h
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*
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* @verbatim
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* Revision History
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*
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* Date Who Description
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* 01-06-2013 Mark Riddoch Initial implementation
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* 14-06-2013 Massimiliano Pinto Added void *data to session
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* for session specific data
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* 01-07-2013 Massimiliano Pinto Removed backends pointer
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* from struct session
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* 02-09-2013 Massimiliano Pinto Added session ref counter
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* 29-05-2014 Mark Riddoch Support for filter mechanism
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* added
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*
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* @endverbatim
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*/
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#include <time.h>
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#include <atomic.h>
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#include <buffer.h>
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#include <spinlock.h>
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#include <skygw_utils.h>
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struct dcb;
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struct service;
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struct filter_def;
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/**
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* The session statistics structure
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*/
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typedef struct {
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time_t connect; /**< Time when the session was started */
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} SESSION_STATS;
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typedef enum {
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SESSION_STATE_ALLOC, /*< for all sessions */
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SESSION_STATE_READY, /*< for router session */
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SESSION_STATE_ROUTER_READY, /*< for router session */
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SESSION_STATE_STOPPING, /*< session and router are being closed */
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SESSION_STATE_LISTENER, /*< for listener session */
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SESSION_STATE_LISTENER_STOPPED, /*< for listener session */
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SESSION_STATE_FREE /*< for all sessions */
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} session_state_t;
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/**
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* The downstream element in the filter chain. This may refer to
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* another filter or to a router.
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*/
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typedef struct {
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void *instance;
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void *session;
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int (*routeQuery)(void *instance,
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void *router_session, GWBUF *queue);
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} DOWNSTREAM;
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/**
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* The upstream element in the filter chain. This may refer to
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* another filter or to the protocol implementation.
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*/
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typedef struct {
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void *instance;
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void *session;
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int (*write)(void *, void *, GWBUF *);
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int (*error)(void *);
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} UPSTREAM;
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/**
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* Structure used to track the filter instances and sessions of the filters
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* that are in use within a session.
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*/
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typedef struct {
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struct filter_def
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*filter;
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void *instance;
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void *session;
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} SESSION_FILTER;
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/**
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* The session status block
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*
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* A session status block is created for each user (client) connection
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* to the database, it links the descriptors, routing implementation
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* and originating service together for the client session.
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*/
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typedef struct session {
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#if defined(SS_DEBUG)
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skygw_chk_t ses_chk_top;
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#endif
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SPINLOCK ses_lock;
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session_state_t state; /**< Current descriptor state */
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struct dcb *client; /**< The client connection */
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void *data; /**< The session data */
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void *router_session;/**< The router instance data */
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SESSION_STATS stats; /**< Session statistics */
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struct service *service; /**< The service this session is using */
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int n_filters; /**< Number of filter sessions */
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SESSION_FILTER *filters; /**< The filters in use within this session */
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DOWNSTREAM head; /**< Head of the filter chain */
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struct session *next; /**< Linked list of all sessions */
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int refcount; /**< Reference count on the session */
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#if defined(SS_DEBUG)
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skygw_chk_t ses_chk_tail;
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#endif
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} SESSION;
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#define SESSION_PROTOCOL(x, type) DCB_PROTOCOL((x)->client, type)
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/**
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* A convenience macro that can be used by the protocol modules to route
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* the incoming data to the first element in the pipeline of filters and
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* routers.
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*/
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#define SESSION_ROUTE_QUERY(session, buf) \
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((session)->head.routeQuery)((session)->head.instance, \
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(session)->head.session, (buf))
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SESSION *session_alloc(struct service *, struct dcb *);
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bool session_free(SESSION *);
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int session_isvalid(SESSION *);
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void printAllSessions();
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void printSession(SESSION *);
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void dprintAllSessions(struct dcb *);
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void dprintSession(struct dcb *, SESSION *);
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void dListSessions(struct dcb *);
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char *session_state(int);
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bool session_link_dcb(SESSION *, struct dcb *);
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SESSION* get_session_by_router_ses(void* rses);
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#endif
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