1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
|
/*
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"
/* 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 '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;
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);
/*
* 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'.
*/
int fo_new_service(struct fo_ctx *ctx,
const char *name,
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);
/*
* 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);
int fo_add_srv_server(struct fo_service *service,
const char *srv,
const char *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);
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);
struct hostent *fo_get_server_hostent(struct fo_server *server);
int fo_is_srv_lookup(struct fo_server *s);
#endif /* !__FAIL_OVER_H__ */
|
