Addition of example filter to set routing hint to route to a named server
based on a regular expression match within the query text.
This commit is contained in:
Mark Riddoch
parent
113ea8381b
commit
41bc0ddd24
@ -28,6 +28,10 @@ add_library(fwfilter SHARED fwfilter.c)
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target_link_libraries(fwfilter log_manager utils query_classifier)
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install(TARGETS fwfilter DESTINATION modules)
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add_library(namedserverfilter SHARED namedserverfilter.c)
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target_link_libraries(namedserverfilter log_manager utils)
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install(TARGETS namedserverfilter DESTINATION modules)
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add_subdirectory(hint)
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381
server/modules/filter/namedserverfilter.c
Normal file
381
server/modules/filter/namedserverfilter.c
Normal file
@ -0,0 +1,381 @@
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/*
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* This file is distributed as part of MaxScale by MariaDB Corporation. 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 MariaDB Corporation Ab 2014
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*/
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#include <stdio.h>
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#include <filter.h>
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#include <modinfo.h>
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#include <modutil.h>
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#include <skygw_utils.h>
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#include <log_manager.h>
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#include <string.h>
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#include <regex.h>
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#include <hint.h>
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/** Defined in log_manager.cc */
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extern int lm_enabled_logfiles_bitmask;
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extern size_t log_ses_count[];
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extern __thread log_info_t tls_log_info;
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/**
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* @file namedserverfilter.c - a very simple regular expression based filter
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* that routes to a named server if a regular expression match is found.
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* @verbatim
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*
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* A simple regular expression query rewrite filter.
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* Two parameters should be defined in the filter configuration
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* match=<regular expression>
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* server=<server to route statement to>
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* Two optional parameters
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* source=<source address to limit filter>
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* user=<username to limit filter>
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*
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* Date Who Description
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* 22/01/2015 Mark Riddoch Written as example based on regex filter
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* @endverbatim
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*/
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MODULE_INFO info = {
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MODULE_API_FILTER,
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MODULE_GA,
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FILTER_VERSION,
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"A routing hint filter that uses regular expressions to direct queries"
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};
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static char *version_str = "V1.1.0";
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static FILTER *createInstance(char **options, FILTER_PARAMETER **params);
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static void *newSession(FILTER *instance, SESSION *session);
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static void closeSession(FILTER *instance, void *session);
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static void freeSession(FILTER *instance, void *session);
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static void setDownstream(FILTER *instance, void *fsession, DOWNSTREAM *downstream);
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static int routeQuery(FILTER *instance, void *fsession, GWBUF *queue);
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static void diagnostic(FILTER *instance, void *fsession, DCB *dcb);
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static FILTER_OBJECT MyObject = {
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createInstance,
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newSession,
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closeSession,
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freeSession,
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setDownstream,
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NULL, // No Upstream requirement
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routeQuery,
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NULL,
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diagnostic,
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};
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/**
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* Instance structure
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*/
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typedef struct {
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char *source; /* Source address to restrict matches */
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char *user; /* User name to restrict matches */
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char *match; /* Regular expression to match */
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char *server; /* Server to route to */
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int cflags; /* Regexec compile flags */
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regex_t re; /* Compiled regex text */
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} REGEXHINT_INSTANCE;
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/**
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* The session structuee for this regex filter
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*/
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typedef struct {
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DOWNSTREAM down; /* The downstream filter */
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int n_diverted; /* No. of statements diverted */
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int n_undiverted; /* No. of statements not diverted */
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int active; /* Is filter active */
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} REGEXHINT_SESSION;
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/**
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* Implementation of the mandatory version entry point
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*
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* @return version string of the module
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*/
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char *
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version()
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{
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return version_str;
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}
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/**
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* The module initialisation routine, called when the module
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* is first loaded.
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*/
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void
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ModuleInit()
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{
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}
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/**
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* The module entry point routine. It is this routine that
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* must populate the structure that is referred to as the
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* "module object", this is a structure with the set of
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* external entry points for this module.
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*
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* @return The module object
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*/
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FILTER_OBJECT *
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GetModuleObject()
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{
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return &MyObject;
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}
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/**
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* Create an instance of the filter for a particular service
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* within MaxScale.
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*
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* @param options The options for this filter
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* @param params The array of name/value pair parameters for the filter
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*
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* @return The instance data for this new instance
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*/
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static FILTER *
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createInstance(char **options, FILTER_PARAMETER **params)
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{
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REGEXHINT_INSTANCE *my_instance;
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int i, cflags = REG_ICASE;
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if ((my_instance = calloc(1, sizeof(REGEXHINT_INSTANCE))) != NULL)
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{
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my_instance->match = NULL;
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my_instance->server = NULL;
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for (i = 0; params && params[i]; i++)
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{
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if (!strcmp(params[i]->name, "match"))
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my_instance->match = strdup(params[i]->value);
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else if (!strcmp(params[i]->name, "server"))
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my_instance->server = strdup(params[i]->value);
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else if (!strcmp(params[i]->name, "source"))
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my_instance->source = strdup(params[i]->value);
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else if (!strcmp(params[i]->name, "user"))
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my_instance->user = strdup(params[i]->value);
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else if (!filter_standard_parameter(params[i]->name))
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{
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LOGIF(LE, (skygw_log_write_flush(
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LOGFILE_ERROR,
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"namedserverfilter: Unexpected parameter '%s'.\n",
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params[i]->name)));
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}
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}
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if (options)
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{
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for (i = 0; options[i]; i++)
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{
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if (!strcasecmp(options[i], "ignorecase"))
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{
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cflags |= REG_ICASE;
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}
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else if (!strcasecmp(options[i], "case"))
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{
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cflags &= ~REG_ICASE;
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}
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else
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{
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LOGIF(LE, (skygw_log_write_flush(
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LOGFILE_ERROR,
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"namedserverfilter: unsupported option '%s'.\n",
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options[i])));
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}
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}
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}
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my_instance->cflags = cflags;
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if (my_instance->match == NULL || my_instance->server == NULL)
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{
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LOGIF(LE, (skygw_log_write_flush(
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LOGFILE_ERROR,
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"namedserverfilter: Missing required configured"
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" option. You must specify a match and server "
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"option as a minimum.")));
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free(my_instance);
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return NULL;
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}
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if (regcomp(&my_instance->re, my_instance->match,
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my_instance->cflags))
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{
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LOGIF(LE, (skygw_log_write_flush(LOGFILE_ERROR,
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"namedserverfilter: Invalid regular expression '%s'.\n",
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my_instance->match)));
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free(my_instance->match);
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free(my_instance->server);
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free(my_instance);
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return NULL;
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}
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}
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return (FILTER *)my_instance;
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}
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/**
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* Associate a new session with this instance of the filter.
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*
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* @param instance The filter instance data
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* @param session The session itself
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* @return Session specific data for this session
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*/
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static void *
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newSession(FILTER *instance, SESSION *session)
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{
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REGEXHINT_INSTANCE *my_instance = (REGEXHINT_INSTANCE *)instance;
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REGEXHINT_SESSION *my_session;
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char *remote, *user;
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if ((my_session = calloc(1, sizeof(REGEXHINT_SESSION))) != NULL)
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{
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my_session->n_diverted = 0;
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my_session->n_undiverted = 0;
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my_session->active = 1;
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if (my_instance->source
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&& (remote = session_get_remote(session)) != NULL)
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{
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if (strcmp(remote, my_instance->source))
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my_session->active = 0;
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}
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if (my_instance->user && (user = session_getUser(session))
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&& strcmp(user, my_instance->user))
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{
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my_session->active = 0;
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}
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}
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return my_session;
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}
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/**
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* Close a session with the filter, this is the mechanism
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* by which a filter may cleanup data structure etc.
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*
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* @param instance The filter instance data
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* @param session The session being closed
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*/
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static void
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closeSession(FILTER *instance, void *session)
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{
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}
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/**
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* Free the memory associated with this filter session.
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*
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* @param instance The filter instance data
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* @param session The session being closed
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*/
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static void
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freeSession(FILTER *instance, void *session)
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{
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free(session);
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return;
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}
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/**
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* Set the downstream component for this filter.
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*
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* @param instance The filter instance data
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* @param session The session being closed
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* @param downstream The downstream filter or router
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*/
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static void
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setDownstream(FILTER *instance, void *session, DOWNSTREAM *downstream)
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{
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REGEXHINT_SESSION *my_session = (REGEXHINT_SESSION *)session;
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my_session->down = *downstream;
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}
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/**
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* The routeQuery entry point. This is passed the query buffer
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* to which the filter should be applied. Once applied the
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* query should normally be passed to the downstream component
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* (filter or router) in the filter chain.
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*
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* If the regular expressed configured in the match parameter of the
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* filter definition matches the SQL text then add the hint
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* "Route to named server" with the name defined in the server parameter
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*
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* @param instance The filter instance data
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* @param session The filter session
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* @param queue The query data
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*/
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static int
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routeQuery(FILTER *instance, void *session, GWBUF *queue)
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{
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REGEXHINT_INSTANCE *my_instance = (REGEXHINT_INSTANCE *)instance;
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REGEXHINT_SESSION *my_session = (REGEXHINT_SESSION *)session;
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char *sql;
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if (modutil_is_SQL(queue))
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{
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if (queue->next != NULL)
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{
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queue = gwbuf_make_contiguous(queue);
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}
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if ((sql = modutil_get_SQL(queue)) != NULL)
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{
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if (regexec(&my_instance->re,sql,0,NULL, 0) == 0)
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{
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queue->hint = hint_create_route(queue->hint,
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HINT_ROUTE_TO_NAMED_SERVER,
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my_instance->server);
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my_session->n_diverted++;
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}
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else
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my_session->n_undiverted++;
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free(sql);
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}
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}
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return my_session->down.routeQuery(my_session->down.instance,
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my_session->down.session, queue);
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}
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/**
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* Diagnostics routine
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*
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* If fsession is NULL then print diagnostics on the filter
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* instance as a whole, otherwise print diagnostics for the
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* particular session.
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*
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* @param instance The filter instance
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* @param fsession Filter session, may be NULL
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* @param dcb The DCB for diagnostic output
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*/
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static void
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diagnostic(FILTER *instance, void *fsession, DCB *dcb)
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{
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REGEXHINT_INSTANCE *my_instance = (REGEXHINT_INSTANCE *)instance;
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REGEXHINT_SESSION *my_session = (REGEXHINT_SESSION *)fsession;
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dcb_printf(dcb, "\t\tMatch and route: /%s/ -> %s\n",
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my_instance->match, my_instance->server);
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if (my_session)
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{
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dcb_printf(dcb, "\t\tNo. of queries diverted by filter: %d\n",
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my_session->n_diverted);
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dcb_printf(dcb, "\t\tNo. of queries not diverted by filter: %d\n",
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my_session->n_undiverted);
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}
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if (my_instance->source)
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dcb_printf(dcb,
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"\t\tReplacement limited to connections from %s\n",
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my_instance->source);
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if (my_instance->user)
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dcb_printf(dcb,
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"\t\tReplacement limit to user %s\n",
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my_instance->user);
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}
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