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/*
SSSD
Fail over helper functions.
Authors:
Martin Nagy <mnagy@redhat.com>
Copyright (C) Red Hat, Inc 2009
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef __FAIL_OVER_H__
#define __FAIL_OVER_H__
#include <stdbool.h>
#include <talloc.h>
#include "resolv/async_resolv.h"
#define FO_PROTO_TCP "tcp"
#define FO_PROTO_UDP "udp"
#define FO_DEFAULT_SVC_TIMEOUT 10
/* Some forward declarations that don't have to do anything with fail over. */
struct hostent;
struct tevent_context;
struct tevent_req;
enum port_status {
PORT_NEUTRAL, /* We didn't try this port yet. */
PORT_WORKING, /* This port was reported to work. */
PORT_NOT_WORKING /* This port was reported to not work. */
};
enum server_status {
SERVER_NAME_NOT_RESOLVED, /* We didn't yet resolved the host name. */
SERVER_RESOLVING_NAME, /* Name resolving is in progress. */
SERVER_NAME_RESOLVED, /* We resolved the host name but didn't try to connect. */
SERVER_WORKING, /* We successfully connected to the server. */
SERVER_NOT_WORKING /* We tried and failed to connect to the server. */
};
struct fo_ctx;
struct fo_service;
struct fo_server;
/*
* Failover settings.
*
* The 'retry_timeout' member specifies the
* duration in seconds of how long a server or port will be considered
* non-working after being marked as such.
*
* The 'service_resolv_timeout' member specifies how long we wait for
* service resolution. When this timeout is reached, the resolve request
* is cancelled with an error
*
* The 'srv_retry_timeout' member specifies how long a SRV lookup
* is considered valid until we ask the server again.
*
* The family_order member specifies the order of address families to
* try when looking up the service.
*/
struct fo_options {
time_t srv_retry_timeout;
time_t retry_timeout;
int service_resolv_timeout;
enum restrict_family family_order;
};
/*
* Create a new fail over context based on options passed in the
* opts parameter
*/
struct fo_ctx *fo_context_init(TALLOC_CTX *mem_ctx,
struct fo_options *opts);
typedef int (*datacmp_fn)(void*, void*);
/*
* Create a new service structure for 'ctx', saving it to the location pointed
* to by '_service'. The needed memory will be allocated from 'ctx'.
* Service name will be set to 'name'.
*
* Function pointed by user_data_cmp returns 0 if user_data is equal
* or nonzero value if not. Set to NULL if no user data comparison
* is needed in fail over duplicate servers detection.
*/
int fo_new_service(struct fo_ctx *ctx,
const char *name,
datacmp_fn user_data_cmp,
struct fo_service **_service);
/*
* Look up service named 'name' from the 'ctx' service list. Target of
* '_service' will be set to the service if it was found.
*/
int fo_get_service(struct fo_ctx *ctx,
const char *name,
struct fo_service **_service);
/*
* Get number of servers registered for the 'service'.
*/
int fo_get_server_count(struct fo_service *service);
/*
* Adds a server 'name' to the 'service'. Port 'port' will be used for
* connection. If 'name' is NULL, no server resolution will be done.
*/
int fo_add_server(struct fo_service *service,
const char *name, int port,
void *user_data, bool primary);
int fo_add_srv_server(struct fo_service *service,
const char *srv,
const char *discovery_domain,
const char *sssd_domain,
const char *proto,
void *user_data);
/*
* Request the first server from the service's list of servers. It is only
* considered if it is not marked as not working (or the retry interval already
* passed). If the server address wasn't resolved yet, it will be done.
*/
struct tevent_req *fo_resolve_service_send(TALLOC_CTX *mem_ctx,
struct tevent_context *ev,
struct resolv_ctx *resolv,
struct fo_ctx *ctx,
struct fo_service *service);
int fo_resolve_service_recv(struct tevent_req *req,
struct fo_server **server);
/*
* Set feedback about 'server'. Caller should use this to indicate a problem
* with the server itself, not only with the service on that server. This
* should be used, for example, when the IP address of the server can't be
* reached. This setting can affect other services as well, since they can
* share the same server.
*/
void fo_set_server_status(struct fo_server *server,
enum server_status status);
/*
* Set feedback about the port status. This function should be used when
* the server itself is working but the service is not. When status is set
* to PORT_WORKING, 'server' is also marked as an "active server" for its
* service. When the next fo_resolve_service_send() function is called, this
* server will be preferred. This will hold as long as it is not marked as
* not-working.
*/
void fo_set_port_status(struct fo_server *server,
enum port_status status);
/*
* Instruct fail-over to try next server on the next connect attempt.
* Should be used after connection to service was unexpectedly dropped
* but there is no authoritative information on whether active server is down.
*/
void fo_try_next_server(struct fo_service *service);
void *fo_get_server_user_data(struct fo_server *server);
int fo_get_server_port(struct fo_server *server);
const char *fo_get_server_name(struct fo_server *server);
const char *fo_get_server_str_name(struct fo_server *server);
struct resolv_hostent *fo_get_server_hostent(struct fo_server *server);
bool fo_is_server_primary(struct fo_server *server);
time_t fo_get_server_hostname_last_change(struct fo_server *server);
int fo_is_srv_lookup(struct fo_server *s);
time_t fo_get_service_retry_timeout(struct fo_service *svc);
void fo_reset_services(struct fo_ctx *fo_ctx);
bool fo_svc_has_server(struct fo_service *service, struct fo_server *server);
#endif /* !__FAIL_OVER_H__ */
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