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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: acl.h,v 1.5 2004/04/08 01:36:25 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 | |
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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 | |
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40 | #include <sys/types.h> |
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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 */ |
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50 | const struct acl_ops *ops; /* Operations for the ACL entry */ |
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51 | unsigned act; /* What to do with matching hosts */ |
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52 | } acl_entry; |
53 | |
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54 | #define ACL_DENY 0 /* Deny access to matching conns */ |
55 | #define ACL_ALLOW 1 /* Allow access to matching conns */ |
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56 | #define ACL_PERM 1u /* Bit mask for permission bit */ |
57 | |
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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 | |
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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 |
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79 | * @unsigned port@ = port number to check |
80 | * @int *act@ = verdict (should initially be @ACT_ALLOW@) |
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81 | * |
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82 | * Returns: Zero if undecided, nonzero if a rule matched. |
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83 | * |
84 | * Use: Checks an address against an ACL. |
85 | */ |
86 | |
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87 | extern int acl_check(acl_entry */*a*/, |
88 | struct in_addr /*addr*/, unsigned /*port*/, |
89 | int */*act*/); |
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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 | |
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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 | |
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114 | /* --- @acl_addhost@ --- * |
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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 | * |
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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. |
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138 | */ |
139 | |
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140 | extern void acl_addpriv(acl_entry ***/*a*/, unsigned /*act*/); |
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141 | |
142 | /*----- That's all, folks -------------------------------------------------*/ |
143 | |
144 | #ifdef __cplusplus |
145 | } |
146 | #endif |
147 | |
148 | #endif |