3 * $Id: bres.h,v 1.5 2004/04/08 01:36:11 mdw Exp $
5 * Background reverse name resolution
7 * (c) 1999 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of the mLib utilities library.
14 * mLib is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU Library General Public License as
16 * published by the Free Software Foundation; either version 2 of the
17 * License, or (at your option) any later version.
19 * mLib is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU Library General Public License for more details.
24 * You should have received a copy of the GNU Library General Public
25 * License along with mLib; if not, write to the Free
26 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
37 /*----- Header files ------------------------------------------------------*/
39 #include <sys/types.h>
41 #include <sys/socket.h>
42 #include <netinet/in.h>
43 #include <arpa/inet.h>
53 /*----- Data structures ---------------------------------------------------*/
55 /* --- Client allocated request block --- */
57 typedef struct bres_client {
59 adns_query aq; /* ADNS query handle */
60 adns_answer *a; /* Answer for reverse resolution */
61 struct _unused *_pad1; /* And a spare slot */
63 struct bres_client *next, *prev; /* Queue of waiting resolve jobs */
64 struct bres_server *rs; /* Pointer to attached server */
66 int q; /* Query type (name or address) */
68 struct in_addr addr; /* Address to resolve */
69 char *name; /* Name to resolve */
71 void (*func)(struct hostent */*h*/, void */*p*/); /* Handler function */
72 void *p; /* Argument for handler function */
75 /* --- Server maintained resolver blocks --- */
77 typedef struct bres_server {
78 struct bres_server *next, *prev; /* Doubly-linked list of servers */
79 pid_t kid; /* Process id of server process */
80 int fd; /* File descriptors */
81 struct bres_client *rc; /* Pointer to attached client */
82 sel_timer t; /* Timeout for idle servers */
83 sel_file f; /* Read selector for server */
86 /*----- Functions provided ------------------------------------------------*/
88 /* --- @bres_abort@ --- *
90 * Arguments: @bres_client *rc@ = pointer to client block
94 * Use: Removes a queued job.
97 extern void bres_abort(bres_client */*rc*/);
99 /* --- @bres_byaddr@ --- *
101 * Arguments: @bres_client *rc@ = pointer to client block
102 * @struct in_addr addr@ = address to resolve
103 * @void (*func)(struct hostent *h, void *p)@ = handler function
104 * @void *p@ = argument for handler function
108 * Use: Adds an address lookup job to the queue. The job will be
109 * processed when there's a spare resolver process to deal with
113 extern void bres_byaddr(bres_client */*rc*/, struct in_addr /*addr*/,
114 void (*/*func*/)(struct hostent */*h*/, void */*p*/),
117 /* --- @bres_byname@ --- *
119 * Arguments: @bres_client *rc@ = pointer to client block
120 * @const char *name@ = name to resolve
121 * @void (*func)(struct hostent *h, void *p)@ = handler function
122 * @void *p@ = argument for handler function
126 * Use: Adds a name lookup job to the queue. The job will be
127 * processed when there's a spare resolver process to deal with
131 extern void bres_byname(bres_client */*rc*/, const char */*name*/,
132 void (*/*func*/)(struct hostent */*h*/, void */*p*/),
135 /* --- @bres_exec@ --- *
137 * Arguments: @const char *file@ = file containing server code or null
141 * Use: Makes `bres' use a standalone server rather than copies of
142 * the current process. This can reduce memory consumption for
143 * large processes, at the expense of startup time (which
144 * shouldn't be too bad anyway, because of the resolver design).
145 * If the filename is null, a default set up at install time is
146 * used. It's probably a good idea to leave it alone.
149 extern void bres_exec(const char */*file*/);
151 /* --- @bres_init@ --- *
153 * Arguments: @sel_state *s@ = pointer to select multiplexor
157 * Use: Initializes the background resolver for use.
160 extern void bres_init(sel_state */*s*/);
162 /*----- That's all, folks -------------------------------------------------*/