e82f7154 |
1 | /* -*-c-*- |
2 | * |
3 | * $Id: acl.c,v 1.1 1999/07/01 08:56:23 mdw Exp $ |
4 | * |
5 | * Access control list handling |
6 | * |
7 | * (c) 1999 Mark Wooding |
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 | /*----- Revision history --------------------------------------------------* |
30 | * |
31 | * $Log: acl.c,v $ |
32 | * Revision 1.1 1999/07/01 08:56:23 mdw |
33 | * Initial revision |
34 | * |
35 | */ |
36 | |
37 | /*----- Header files ------------------------------------------------------*/ |
38 | |
39 | #include "config.h" |
40 | |
41 | #include <errno.h> |
42 | #include <stdio.h> |
43 | #include <stdlib.h> |
44 | #include <string.h> |
45 | |
46 | #include <sys/socket.h> |
47 | #include <netinet/in.h> |
48 | #include <arpa/inet.h> |
49 | #include <netdb.h> |
50 | |
51 | #include <mLib/sub.h> |
52 | |
53 | #include "acl.h" |
54 | |
55 | /*----- Static variables --------------------------------------------------*/ |
56 | |
57 | static acl_entry *global = 0; |
58 | static acl_entry **gtail = &global; |
59 | |
60 | /*----- Main code ---------------------------------------------------------*/ |
61 | |
62 | /* --- @acl_check@ --- * |
63 | * |
64 | * Arguments: @acl_entry *a@ = pointer to ACL to check against |
65 | * @struct in_addr addr@ = address to check |
66 | * |
67 | * Returns: Nonzero if allowed. |
68 | * |
69 | * Use: Checks an address against an ACL. |
70 | */ |
71 | |
72 | int acl_check(acl_entry *a, struct in_addr addr) |
73 | { |
74 | int act = ACL_ALLOW; |
75 | int i; |
76 | |
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; |
82 | } |
83 | a = global; |
84 | } |
85 | |
86 | return (act); |
87 | } |
88 | |
89 | /* --- @acl_dump@ --- * |
90 | * |
91 | * Arguments: @acl_entry *a@ = pointer to ACL to dump |
92 | * @FILE *fp@ = pointer to stream to dump on |
93 | * |
94 | * Returns: --- |
95 | * |
96 | * Use: Dumps an access control list to an output stream. |
97 | */ |
98 | |
99 | void acl_dump(acl_entry *a, FILE *fp) |
100 | { |
101 | if (!a) |
102 | a = global; |
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); |
107 | fputc('/', fp); |
108 | fputs(inet_ntoa(a->mask), fp); |
109 | fputc('\n', fp); |
110 | } |
111 | } |
112 | |
113 | /* --- @acl_add@ --- * |
114 | * |
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 |
118 | * |
119 | * Returns: --- |
120 | * |
121 | * Use: Adds an entry to the end of an access control list. |
122 | */ |
123 | |
124 | void acl_add(acl_entry ***a, unsigned act, |
125 | struct in_addr addr, struct in_addr mask) |
126 | { |
127 | acl_entry *aa = CREATE(acl_entry); |
128 | aa->act = act; |
129 | aa->addr.s_addr = addr.s_addr & mask.s_addr; |
130 | aa->mask = mask; |
131 | aa->next = 0; |
132 | if (!a) |
133 | a = >ail; |
134 | **a = aa; |
135 | *a = &aa->next; |
136 | } |
137 | |
138 | /*----- That's all, folks -------------------------------------------------*/ |