mdw@git.distorted.org.uk Git - mLib/blob - sel/bres.h

   1 /* -*-c-*-
   2  *
   3  * Background reverse name resolution
   4  *
   5  * (c) 1999 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of the mLib utilities library.
  11  *
  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.
  16  *
  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.
  21  *
  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,
  25  * MA 02111-1307, USA.
  26  */
  27
  28 #ifndef MLIB_BRES_H
  29 #define MLIB_BRES_H
  30
  31 #ifdef __cplusplus
  32   extern "C" {
  33 #endif
  34
  35 /*----- Header files ------------------------------------------------------*/
  36
  37 #include <sys/types.h>
  38
  39 #include <sys/socket.h>
  40 #include <netinet/in.h>
  41 #include <arpa/inet.h>
  42 #include <netdb.h>
  43
  44 #ifdef HAVE_ADNS
  45 #  include <adns.h>
  46 #endif
  47
  48 #ifndef MLIB_SEL_H
  49 #  include "sel.h"
  50 #endif
  51
  52 #ifndef MLIB_SELBUF_H
  53 #  include "selbuf.h"
  54 #endif
  55
  56 /*----- Data structures ---------------------------------------------------*/
  57
  58 /* --- Client allocated request block --- */
  59
  60 typedef struct bres_client {
  61 #ifdef HAVE_ADNS
  62   adns_query aq;                        /* ADNS query handle */
  63   adns_answer *a;                       /* Answer for reverse resolution */
  64   struct _unused *_pad1;                /* And a spare slot */
  65 #else
  66   struct bres_client *next, *prev;      /* Queue of waiting resolve jobs */
  67   struct bres_server *rs;               /* Pointer to attached server */
  68 #endif
  69   int q;                                /* Query type (name or address) */
  70   union {
  71     struct in_addr addr;                /* Address to resolve */
  72     char *name;                         /* Name to resolve */
  73   } u;
  74   void (*func)(struct hostent */*h*/, void */*p*/); /* Handler function */
  75   void *p;                              /* Argument for handler function */
  76 } bres_client;
  77
  78 /* --- Server maintained resolver blocks --- */
  79
  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 */
  87 } bres_server;
  88
  89 /*----- Functions provided ------------------------------------------------*/
  90
  91 /* --- @bres_abort@ --- *
  92  *
  93  * Arguments:   @bres_client *rc@ = pointer to client block
  94  *
  95  * Returns:     ---
  96  *
  97  * Use:         Removes a queued job.
  98  */
  99
 100 extern void bres_abort(bres_client */*rc*/);
 101
 102 /* --- @bres_byaddr@ --- *
 103  *
 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
 108  *
 109  * Returns:     ---
 110  *
 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
 113  *              it.
 114  */
 115
 116 extern void bres_byaddr(bres_client */*rc*/, struct in_addr /*addr*/,
 117                         void (*/*func*/)(struct hostent */*h*/, void */*p*/),
 118                         void */*p*/);
 119
 120 /* --- @bres_byname@ --- *
 121  *
 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
 126  *
 127  * Returns:     ---
 128  *
 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
 131  *              it.
 132  */
 133
 134 extern void bres_byname(bres_client */*rc*/, const char */*name*/,
 135                         void (*/*func*/)(struct hostent */*h*/, void */*p*/),
 136                         void */*p*/);
 137
 138 /* --- @bres_exec@ --- *
 139  *
 140  * Arguments:   @const char *file@ = file containing server code or null
 141  *
 142  * Returns:     ---
 143  *
 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.
 150  */
 151
 152 extern void bres_exec(const char */*file*/);
 153
 154 /* --- @bres_init@ --- *
 155  *
 156  * Arguments:   @sel_state *s@ = pointer to select multiplexor
 157  *
 158  * Returns:     ---
 159  *
 160  * Use:         Initializes the background resolver for use.
 161  */
 162
 163 extern void bres_init(sel_state */*s*/);
 164
 165 /*----- That's all, folks -------------------------------------------------*/
 166
 167 #ifdef __cplusplus
 168   }
 169 #endif
 170
 171 #endif