mdw@git.distorted.org.uk Git - fwd/blob - acl.h

   1 /* -*-c-*-
   2  *
   3  * $Id: acl.h,v 1.5 2004/04/08 01:36:25 mdw Exp $
   4  *
   5  * Access control list handling
   6  *
   7  * (c) 1999 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of the `fw' port forwarder.
  13  *
  14  * `fw' is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * `fw' 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 General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with `fw'; if not, write to the Free Software Foundation,
  26  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  27  */
  28
  29 #ifndef ACL_H
  30 #define ACL_H
  31
  32 #ifdef __cplusplus
  33   extern "C" {
  34 #endif
  35
  36 /*----- Header files ------------------------------------------------------*/
  37
  38 #include <stdio.h>
  39
  40 #include <sys/types.h>
  41 #include <sys/socket.h>
  42 #include <netinet/in.h>
  43
  44 /*----- Data structures ---------------------------------------------------*/
  45
  46 /* --- An access control entry --- */
  47
  48 typedef struct acl_entry {
  49   struct acl_entry *next;               /* Next entry in the list */
  50   const struct acl_ops *ops;            /* Operations for the ACL entry */
  51   unsigned act;                         /* What to do with matching hosts */
  52 } acl_entry;
  53
  54 #define ACL_DENY 0                      /* Deny access to matching conns */
  55 #define ACL_ALLOW 1                     /* Allow access to matching conns */
  56 #define ACL_PERM 1u                     /* Bit mask for permission bit */
  57
  58 /* --- Host-based access control --- */
  59
  60 typedef struct acl_host {
  61   acl_entry a;                          /* Base structure */
  62   struct in_addr addr, mask;            /* Address and netmask */
  63 } acl_host;
  64
  65 /* --- ACL methods --- */
  66
  67 typedef struct acl_ops {
  68   int (*check)(void */*a*/, struct in_addr /*addr*/, unsigned /*port*/);
  69   void (*dump)(void */*a*/, FILE */*fp*/);
  70   void (*free)(void */*a*/);
  71 } acl_ops;
  72
  73 /*----- Functions provided ------------------------------------------------*/
  74
  75 /* --- @acl_check@ --- *
  76  *
  77  * Arguments:   @acl_entry *a@ = pointer to ACL to check against
  78  *              @struct in_addr addr@ = address to check
  79  *              @unsigned port@ = port number to check
  80  *              @int *act@ = verdict (should initially be @ACT_ALLOW@)
  81  *
  82  * Returns:     Zero if undecided, nonzero if a rule matched.
  83  *
  84  * Use:         Checks an address against an ACL.
  85  */
  86
  87 extern int acl_check(acl_entry */*a*/,
  88                      struct in_addr /*addr*/, unsigned /*port*/,
  89                      int */*act*/);
  90
  91 /* --- @acl_dump@ --- *
  92  *
  93  * Arguments:   @acl_entry *a@ = pointer to ACL to dump
  94  *              @FILE *fp@ = pointer to stream to dump on
  95  *
  96  * Returns:     ---
  97  *
  98  * Use:         Dumps an access control list to an output stream.
  99  */
 100
 101 extern void acl_dump(acl_entry */*a*/, FILE */*fp*/);
 102
 103 /* --- @acl_free@ --- *
 104  *
 105  * Arguments:   @acl_entry *a@ = pointer to a list of ACLs
 106  *
 107  * Returns:     ---
 108  *
 109  * Use:         Frees all of the memory used by an ACL.
 110  */
 111
 112 extern void acl_free(acl_entry */*a*/);
 113
 114 /* --- @acl_addhost@ --- *
 115  *
 116  * Arguments:   @acl_entry ***a@ = address of pointer to list tail
 117  *              @unsigned act@ = what to do with matching addresses
 118  *              @struct in_addr addr, mask@ = address and mask to match
 119  *
 120  * Returns:     ---
 121  *
 122  * Use:         Adds a host-authentication entry to the end of an access
 123  *              control list.
 124  */
 125
 126 extern void acl_addhost(acl_entry ***/*a*/, unsigned /*act*/,
 127                         struct in_addr /*addr*/, struct in_addr /*mask*/);
 128
 129 /* --- @acl_addpriv@ --- *
 130  *
 131  * Arguments:   @acl_entry ***a@ = address of pointer to list tail
 132  *              @unsigned act@ = what to do with matching addresses
 133  *
 134  * Returns:     ---
 135  *
 136  * Use:         Adds a privileged-port check to the end of an access control
 137  *              list.
 138  */
 139
 140 extern void acl_addpriv(acl_entry ***/*a*/, unsigned /*act*/);
 141
 142 /*----- That's all, folks -------------------------------------------------*/
 143
 144 #ifdef __cplusplus
 145   }
 146 #endif
 147
 148 #endif