3 * Background reverse name resolution
5 * (c) 1999 Straylight/Edgeware
8 /*----- Licensing notice --------------------------------------------------*
10 * This file is part of the mLib utilities library.
12 * mLib is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU Library General Public License as
14 * published by the Free Software Foundation; either version 2 of the
15 * License, or (at your option) any later version.
17 * mLib is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU Library General Public License for more details.
22 * You should have received a copy of the GNU Library General Public
23 * License along with mLib; if not, write to the Free
24 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
35 /*----- Header files ------------------------------------------------------*/
37 #include <sys/types.h>
39 #include <sys/socket.h>
40 #include <netinet/in.h>
41 #include <arpa/inet.h>
56 /*----- Data structures ---------------------------------------------------*/
58 /* --- Client allocated request block --- */
60 typedef struct bres_client {
62 adns_query aq; /* ADNS query handle */
63 adns_answer *a; /* Answer for reverse resolution */
64 struct _unused *_pad1; /* And a spare slot */
66 struct bres_client *next, *prev; /* Queue of waiting resolve jobs */
67 struct bres_server *rs; /* Pointer to attached server */
69 int q; /* Query type (name or address) */
71 struct in_addr addr; /* Address to resolve */
72 char *name; /* Name to resolve */
74 void (*func)(struct hostent */*h*/, void */*p*/); /* Handler function */
75 void *p; /* Argument for handler function */
78 /* --- Server maintained resolver blocks --- */
80 typedef struct bres_server {
81 struct bres_server *next, *prev; /* Doubly-linked list of servers */
82 pid_t kid; /* Process id of server process */
83 int fd; /* File descriptors */
84 struct bres_client *rc; /* Pointer to attached client */
85 sel_timer t; /* Timeout for idle servers */
86 sel_file f; /* Read selector for server */
89 /*----- Functions provided ------------------------------------------------*/
91 /* --- @bres_abort@ --- *
93 * Arguments: @bres_client *rc@ = pointer to client block
97 * Use: Removes a queued job.
100 extern void bres_abort(bres_client */*rc*/);
102 /* --- @bres_byaddr@ --- *
104 * Arguments: @bres_client *rc@ = pointer to client block
105 * @struct in_addr addr@ = address to resolve
106 * @void (*func)(struct hostent *h, void *p)@ = handler function
107 * @void *p@ = argument for handler function
111 * Use: Adds an address lookup job to the queue. The job will be
112 * processed when there's a spare resolver process to deal with
116 extern void bres_byaddr(bres_client */*rc*/, struct in_addr /*addr*/,
117 void (*/*func*/)(struct hostent */*h*/, void */*p*/),
120 /* --- @bres_byname@ --- *
122 * Arguments: @bres_client *rc@ = pointer to client block
123 * @const char *name@ = name to resolve
124 * @void (*func)(struct hostent *h, void *p)@ = handler function
125 * @void *p@ = argument for handler function
129 * Use: Adds a name lookup job to the queue. The job will be
130 * processed when there's a spare resolver process to deal with
134 extern void bres_byname(bres_client */*rc*/, const char */*name*/,
135 void (*/*func*/)(struct hostent */*h*/, void */*p*/),
138 /* --- @bres_exec@ --- *
140 * Arguments: @const char *file@ = file containing server code or null
144 * Use: Makes `bres' use a standalone server rather than copies of
145 * the current process. This can reduce memory consumption for
146 * large processes, at the expense of startup time (which
147 * shouldn't be too bad anyway, because of the resolver design).
148 * If the filename is null, a default set up at install time is
149 * used. It's probably a good idea to leave it alone.
152 extern void bres_exec(const char */*file*/);
154 /* --- @bres_init@ --- *
156 * Arguments: @sel_state *s@ = pointer to select multiplexor
160 * Use: Initializes the background resolver for use.
163 extern void bres_init(sel_state */*s*/);
165 /*----- That's all, folks -------------------------------------------------*/