3 * $Id: acl.c,v 1.1 1999/07/01 08:56:23 mdw Exp $
5 * Access control list handling
7 * (c) 1999 Mark Wooding
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of the `fw' port forwarder.
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.
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.
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.
29 /*----- Revision history --------------------------------------------------*
32 * Revision 1.1 1999/07/01 08:56:23 mdw
37 /*----- Header files ------------------------------------------------------*/
46 #include <sys/socket.h>
47 #include <netinet/in.h>
48 #include <arpa/inet.h>
55 /*----- Static variables --------------------------------------------------*/
57 static acl_entry
*global
= 0;
58 static acl_entry
**gtail
= &global
;
60 /*----- Main code ---------------------------------------------------------*/
62 /* --- @acl_check@ --- *
64 * Arguments: @acl_entry *a@ = pointer to ACL to check against
65 * @struct in_addr addr@ = address to check
67 * Returns: Nonzero if allowed.
69 * Use: Checks an address against an ACL.
72 int acl_check(acl_entry
*a
, struct in_addr addr
)
77 for (i
= 0; i
< 2; i
++) {
78 for (; a
; a
= a
->next
) {
79 if ((addr
.s_addr
& a
->mask
.s_addr
) == a
->addr
.s_addr
)
80 return (a
->act
& ACL_PERM
);
81 act
= (a
->act
& ACL_PERM
) ^ 1;
89 /* --- @acl_dump@ --- *
91 * Arguments: @acl_entry *a@ = pointer to ACL to dump
92 * @FILE *fp@ = pointer to stream to dump on
96 * Use: Dumps an access control list to an output stream.
99 void acl_dump(acl_entry
*a
, FILE *fp
)
103 for (; a
; a
= a
->next
) {
104 fprintf(fp
, " %s from ",
105 (a
->act
& ACL_PERM
) == ACL_ALLOW ?
"allow" : "deny");
106 fputs(inet_ntoa(a
->addr
), fp
);
108 fputs(inet_ntoa(a
->mask
), fp
);
113 /* --- @acl_add@ --- *
115 * Arguments: @acl_entry ***a@ = address of pointer to list tail
116 * @unsigned act@ = what to do with matching addresses
117 * @struct in_addr addr, mask@ = address and mask to match
121 * Use: Adds an entry to the end of an access control list.
124 void acl_add(acl_entry
***a
, unsigned act
,
125 struct in_addr addr
, struct in_addr mask
)
127 acl_entry
*aa
= CREATE(acl_entry
);
129 aa
->addr
.s_addr
= addr
.s_addr
& mask
.s_addr
;
138 /*----- That's all, folks -------------------------------------------------*/