mdw@git.distorted.org.uk Git - mLib/blob - 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_RES_H
  29 #define MLIB_RES_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 #include "sel.h"
  49 #include "selbuf.h"
  50
  51 /*----- Data structures ---------------------------------------------------*/
  52
  53 /* --- Client allocated request block --- */
  54
  55 typedef struct bres_client {
  56 #ifdef HAVE_ADNS
  57   adns_query aq;                        /* ADNS query handle */
  58   adns_answer *a;                       /* Answer for reverse resolution */
  59   struct _unused *_pad1;                /* And a spare slot */
  60 #else
  61   struct bres_client *next, *prev;      /* Queue of waiting resolve jobs */
  62   struct bres_server *rs;               /* Pointer to attached server */
  63 #endif
  64   int q;                                /* Query type (name or address) */
  65   union {
  66     struct in_addr addr;                /* Address to resolve */
  67     char *name;                         /* Name to resolve */
  68   } u;
  69   void (*func)(struct hostent */*h*/, void */*p*/); /* Handler function */
  70   void *p;                              /* Argument for handler function */
  71 } bres_client;
  72
  73 /* --- Server maintained resolver blocks --- */
  74
  75 typedef struct bres_server {
  76   struct bres_server *next, *prev;      /* Doubly-linked list of servers */
  77   pid_t kid;                            /* Process id of server process */
  78   int fd;                               /* File descriptors */
  79   struct bres_client *rc;               /* Pointer to attached client */
  80   sel_timer t;                          /* Timeout for idle servers */
  81   sel_file f;                           /* Read selector for server */
  82 } bres_server;
  83
  84 /*----- Functions provided ------------------------------------------------*/
  85
  86 /* --- @bres_abort@ --- *
  87  *
  88  * Arguments:   @bres_client *rc@ = pointer to client block
  89  *
  90  * Returns:     ---
  91  *
  92  * Use:         Removes a queued job.
  93  */
  94
  95 extern void bres_abort(bres_client */*rc*/);
  96
  97 /* --- @bres_byaddr@ --- *
  98  *
  99  * Arguments:   @bres_client *rc@ = pointer to client block
 100  *              @struct in_addr addr@ = address to resolve
 101  *              @void (*func)(struct hostent *h, void *p)@ = handler function
 102  *              @void *p@ = argument for handler function
 103  *
 104  * Returns:     ---
 105  *
 106  * Use:         Adds an address lookup job to the queue.  The job will be
 107  *              processed when there's a spare resolver process to deal with
 108  *              it.
 109  */
 110
 111 extern void bres_byaddr(bres_client */*rc*/, struct in_addr /*addr*/,
 112                         void (*/*func*/)(struct hostent */*h*/, void */*p*/),
 113                         void */*p*/);
 114
 115 /* --- @bres_byname@ --- *
 116  *
 117  * Arguments:   @bres_client *rc@ = pointer to client block
 118  *              @const char *name@ = name to resolve
 119  *              @void (*func)(struct hostent *h, void *p)@ = handler function
 120  *              @void *p@ = argument for handler function
 121  *
 122  * Returns:     ---
 123  *
 124  * Use:         Adds a name lookup job to the queue.  The job will be
 125  *              processed when there's a spare resolver process to deal with
 126  *              it.
 127  */
 128
 129 extern void bres_byname(bres_client */*rc*/, const char */*name*/,
 130                         void (*/*func*/)(struct hostent */*h*/, void */*p*/),
 131                         void */*p*/);
 132
 133 /* --- @bres_exec@ --- *
 134  *
 135  * Arguments:   @const char *file@ = file containing server code or null
 136  *
 137  * Returns:     ---
 138  *
 139  * Use:         Makes `bres' use a standalone server rather than copies of
 140  *              the current process.  This can reduce memory consumption for
 141  *              large processes, at the expense of startup time (which
 142  *              shouldn't be too bad anyway, because of the resolver design).
 143  *              If the filename is null, a default set up at install time is
 144  *              used.  It's probably a good idea to leave it alone.
 145  */
 146
 147 extern void bres_exec(const char */*file*/);
 148
 149 /* --- @bres_init@ --- *
 150  *
 151  * Arguments:   @sel_state *s@ = pointer to select multiplexor
 152  *
 153  * Returns:     ---
 154  *
 155  * Use:         Initializes the background resolver for use.
 156  */
 157
 158 extern void bres_init(sel_state */*s*/);
 159
 160 /*----- That's all, folks -------------------------------------------------*/
 161
 162 #ifdef __cplusplus
 163   }
 164 #endif
 165
 166 #endif