1 /* Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
3 /** \file acl.c Access control lists for paraslash senders. */
5 #include <netinet/in.h>
6 #include <sys/socket.h>
20 * Describes one entry in the blacklist/whitelist of a paraslash sender.
23 /** The address to be black/whitelisted. */
25 /** The netmask for this entry. */
27 /** The position of this entry in the acl. */
28 struct list_head node
;
32 * Return true if addr_1 matches addr_2 in the first `netmask' bits.
34 static bool v4_addr_match(uint32_t addr_1
, uint32_t addr_2
, uint8_t netmask
)
38 if (netmask
== 0) /* avoid 32-bit shift, which is undefined in C. */
41 mask
<<= (32 - netmask
);
42 return (htonl(addr_1
) & mask
) == (htonl(addr_2
) & mask
);
46 * Find out whether the peer name of a given fd belongs to an acl.
48 * \param fd File descriptor.
49 * \param acl The access control list.
51 * \return One if \a fd belongs to \a acl, zero otherwise.
53 static int acl_lookup(int fd
, struct list_head
*acl
)
55 struct access_info
*ai
, *tmp
;
56 struct sockaddr_storage ss
;
57 socklen_t sslen
= sizeof(ss
);
58 struct in_addr v4_addr
;
60 if (getpeername(fd
, (struct sockaddr
*)&ss
, &sslen
) < 0) {
61 PARA_ERROR_LOG("Can not determine peer address: %s\n", strerror(errno
));
64 extract_v4_addr(&ss
, &v4_addr
);
68 list_for_each_entry_safe(ai
, tmp
, acl
, node
)
69 if (v4_addr_match(v4_addr
.s_addr
, ai
->addr
.s_addr
, ai
->netmask
))
76 * Add an entry to an access control list.
78 * \param acl The access control list.
79 * \param addr The address to add.
80 * \param netmask The netmask to use for this entry.
82 void acl_add_entry(struct list_head
*acl
, char *addr
, int netmask
)
84 struct access_info
*ai
= alloc(sizeof(struct access_info
));
86 inet_pton(AF_INET
, addr
, &ai
->addr
);
87 ai
->netmask
= netmask
;
88 PARA_INFO_LOG("adding %s/%u to access list\n", addr
, ai
->netmask
);
89 para_list_add(&ai
->node
, acl
);
93 * Delete an entry from an access control list.
95 * \param acl The access control list.
96 * \param addr The address to delete.
97 * \param netmask The netmask of the entry to be removed from the list.
99 static void acl_del_entry(struct list_head
*acl
, char *addr
, unsigned netmask
)
101 struct access_info
*ai
, *tmp
;
102 struct in_addr to_delete
;
104 PARA_INFO_LOG("removing entries matching %s/%u\n", addr
, netmask
);
105 inet_pton(AF_INET
, addr
, &to_delete
);
107 list_for_each_entry_safe(ai
, tmp
, acl
, node
) {
108 if (v4_addr_match(to_delete
.s_addr
, ai
->addr
.s_addr
,
109 PARA_MIN(netmask
, ai
->netmask
))) {
110 char dst
[INET_ADDRSTRLEN
+ 1];
111 const char *p
= inet_ntop(AF_INET
, &ai
->addr
.s_addr
,
114 PARA_DEBUG_LOG("removing %s/%u\n", p
,
123 * Compute a string containing the contents of an acl.
125 * \param acl The access control list.
127 * \return A string containing the contents of \a acl, or \p NULL
128 * if \a acl is empty.
130 char *acl_get_contents(struct list_head
*acl
)
132 struct access_info
*ai
, *tmp_ai
;
135 list_for_each_entry_safe(ai
, tmp_ai
, acl
, node
) {
136 char *tmp
= make_message("%s%s/%u ", ret
? ret
: "",
137 inet_ntoa(ai
->addr
), ai
->netmask
);
145 * Check whether the peer name of a given fd is allowed by an acl.
147 * \param fd File descriptor.
148 * \param acl The access control list.
149 * \param default_deny Whether \a acl is a whitelist.
151 * \return Positive if the peer of \a fd is permitted by \a acl, \p -E_ACL_PERM
154 int acl_check_access(int fd
, struct list_head
*acl
, int default_deny
)
156 int match
= acl_lookup(fd
, acl
);
158 return (!match
|| default_deny
) && (match
|| !default_deny
)?
163 * Permit access for a range of IP addresses.
165 * \param addr The address to permit.
166 * \param netmask The netmask of the entry to be permitted.
167 * \param acl The access control list.
168 * \param default_deny Whether \a acl is a whitelist.
170 void acl_allow(char *addr
, int netmask
,
171 struct list_head
*acl
, int default_deny
)
174 acl_add_entry(acl
, addr
, netmask
);
176 acl_del_entry(acl
, addr
, netmask
);
180 * Deny access for a range of IP addresses.
182 * \param addr The address to deny.
183 * \param netmask The netmask of the entry to be denied.
184 * \param acl The access control list.
185 * \param default_deny Whether \a acl is a whitelist.
187 void acl_deny(char *addr
, int netmask
,
188 struct list_head
*acl
, int default_deny
)
190 acl_allow(addr
, netmask
, acl
, !default_deny
);