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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: acl.c,v 1.3 1999/07/27 18:30:53 mdw Exp $ |
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4 | * |
5 | * Access control list handling |
6 | * |
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7 | * (c) 1999 Straylight/Edgeware |
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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 $ |
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32 | * Revision 1.3 1999/07/27 18:30:53 mdw |
33 | * Various minor portability fixes. |
34 | * |
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35 | * Revision 1.2 1999/07/26 23:28:15 mdw |
36 | * Minor modifications for new design. |
37 | * |
38 | * Revision 1.1.1.1 1999/07/01 08:56:23 mdw |
39 | * Initial revision. |
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40 | * |
41 | */ |
42 | |
43 | /*----- Header files ------------------------------------------------------*/ |
44 | |
45 | #include "config.h" |
46 | |
47 | #include <errno.h> |
48 | #include <stdio.h> |
49 | #include <stdlib.h> |
50 | #include <string.h> |
51 | |
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52 | #include <sys/types.h> |
53 | #include <unistd.h> |
54 | |
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55 | #include <sys/socket.h> |
56 | #include <netinet/in.h> |
57 | #include <arpa/inet.h> |
58 | #include <netdb.h> |
59 | |
60 | #include <mLib/sub.h> |
61 | |
62 | #include "acl.h" |
63 | |
64 | /*----- Static variables --------------------------------------------------*/ |
65 | |
66 | static acl_entry *global = 0; |
67 | static acl_entry **gtail = &global; |
68 | |
69 | /*----- Main code ---------------------------------------------------------*/ |
70 | |
71 | /* --- @acl_check@ --- * |
72 | * |
73 | * Arguments: @acl_entry *a@ = pointer to ACL to check against |
74 | * @struct in_addr addr@ = address to check |
75 | * |
76 | * Returns: Nonzero if allowed. |
77 | * |
78 | * Use: Checks an address against an ACL. |
79 | */ |
80 | |
81 | int acl_check(acl_entry *a, struct in_addr addr) |
82 | { |
83 | int act = ACL_ALLOW; |
84 | int i; |
85 | |
86 | for (i = 0; i < 2; i++) { |
87 | for (; a; a = a->next) { |
88 | if ((addr.s_addr & a->mask.s_addr) == a->addr.s_addr) |
89 | return (a->act & ACL_PERM); |
90 | act = (a->act & ACL_PERM) ^ 1; |
91 | } |
92 | a = global; |
93 | } |
94 | |
95 | return (act); |
96 | } |
97 | |
98 | /* --- @acl_dump@ --- * |
99 | * |
100 | * Arguments: @acl_entry *a@ = pointer to ACL to dump |
101 | * @FILE *fp@ = pointer to stream to dump on |
102 | * |
103 | * Returns: --- |
104 | * |
105 | * Use: Dumps an access control list to an output stream. |
106 | */ |
107 | |
108 | void acl_dump(acl_entry *a, FILE *fp) |
109 | { |
110 | if (!a) |
111 | a = global; |
112 | for (; a; a = a->next) { |
113 | fprintf(fp, " %s from ", |
114 | (a->act & ACL_PERM) == ACL_ALLOW ? "allow" : "deny"); |
115 | fputs(inet_ntoa(a->addr), fp); |
116 | fputc('/', fp); |
117 | fputs(inet_ntoa(a->mask), fp); |
118 | fputc('\n', fp); |
119 | } |
120 | } |
121 | |
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122 | /* --- @acl_free@ --- * |
123 | * |
124 | * Arguments: @acl_entry *a@ = pointer to a list of ACLs |
125 | * |
126 | * Returns: --- |
127 | * |
128 | * Use: Frees all of the memory used by an ACL. |
129 | */ |
130 | |
131 | void acl_free(acl_entry *a) |
132 | { |
133 | while (a) { |
134 | acl_entry *aa = a; |
135 | a = a->next; |
136 | DESTROY(aa); |
137 | } |
138 | } |
139 | |
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140 | /* --- @acl_add@ --- * |
141 | * |
142 | * Arguments: @acl_entry ***a@ = address of pointer to list tail |
143 | * @unsigned act@ = what to do with matching addresses |
144 | * @struct in_addr addr, mask@ = address and mask to match |
145 | * |
146 | * Returns: --- |
147 | * |
148 | * Use: Adds an entry to the end of an access control list. |
149 | */ |
150 | |
151 | void acl_add(acl_entry ***a, unsigned act, |
152 | struct in_addr addr, struct in_addr mask) |
153 | { |
154 | acl_entry *aa = CREATE(acl_entry); |
155 | aa->act = act; |
156 | aa->addr.s_addr = addr.s_addr & mask.s_addr; |
157 | aa->mask = mask; |
158 | aa->next = 0; |
159 | if (!a) |
160 | a = >ail; |
161 | **a = aa; |
162 | *a = &aa->next; |
163 | } |
164 | |
165 | /*----- That's all, folks -------------------------------------------------*/ |