3 * $Id: acl.c,v 1.2 1999/07/26 23:28:15 mdw Exp $
5 * Access control list handling
7 * (c) 1999 Straylight/Edgeware
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 1.2 1999/07/26 23:28:15 mdw
33 * Minor modifications for new design.
35 * Revision 1.1.1.1 1999/07/01 08:56:23 mdw
40 /*----- Header files ------------------------------------------------------*/
49 #include <sys/socket.h>
50 #include <netinet/in.h>
51 #include <arpa/inet.h>
58 /*----- Static variables --------------------------------------------------*/
60 static acl_entry
*global
= 0;
61 static acl_entry
**gtail
= &global
;
63 /*----- Main code ---------------------------------------------------------*/
65 /* --- @acl_check@ --- *
67 * Arguments: @acl_entry *a@ = pointer to ACL to check against
68 * @struct in_addr addr@ = address to check
70 * Returns: Nonzero if allowed.
72 * Use: Checks an address against an ACL.
75 int acl_check(acl_entry
*a
, struct in_addr addr
)
80 for (i
= 0; i
< 2; i
++) {
81 for (; a
; a
= a
->next
) {
82 if ((addr
.s_addr
& a
->mask
.s_addr
) == a
->addr
.s_addr
)
83 return (a
->act
& ACL_PERM
);
84 act
= (a
->act
& ACL_PERM
) ^ 1;
92 /* --- @acl_dump@ --- *
94 * Arguments: @acl_entry *a@ = pointer to ACL to dump
95 * @FILE *fp@ = pointer to stream to dump on
99 * Use: Dumps an access control list to an output stream.
102 void acl_dump(acl_entry
*a
, FILE *fp
)
106 for (; a
; a
= a
->next
) {
107 fprintf(fp
, " %s from ",
108 (a
->act
& ACL_PERM
) == ACL_ALLOW ?
"allow" : "deny");
109 fputs(inet_ntoa(a
->addr
), fp
);
111 fputs(inet_ntoa(a
->mask
), fp
);
116 /* --- @acl_free@ --- *
118 * Arguments: @acl_entry *a@ = pointer to a list of ACLs
122 * Use: Frees all of the memory used by an ACL.
125 void acl_free(acl_entry
*a
)
134 /* --- @acl_add@ --- *
136 * Arguments: @acl_entry ***a@ = address of pointer to list tail
137 * @unsigned act@ = what to do with matching addresses
138 * @struct in_addr addr, mask@ = address and mask to match
142 * Use: Adds an entry to the end of an access control list.
145 void acl_add(acl_entry
***a
, unsigned act
,
146 struct in_addr addr
, struct in_addr mask
)
148 acl_entry
*aa
= CREATE(acl_entry
);
150 aa
->addr
.s_addr
= addr
.s_addr
& mask
.s_addr
;
159 /*----- That's all, folks -------------------------------------------------*/