2 * Copyright (C) 2005-2008 Andre Noll <maan@systemlinux.org>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file acl.c Access control lists for paraslash senders. */
16 * Describes one entry in the blacklist/whitelist of a paraslash sender.
19 /** The address to be black/whitelisted. */
21 /** The netmask for this entry. */
23 /** The position of this entry in the acl. */
24 struct list_head node;
29 * Return true if addr_1 matches addr_2 in the first `netmask' bits.
31 static int v4_addr_match(uint32_t addr_1, uint32_t addr_2, uint8_t netmask)
36 mask <<= (32 - netmask);
37 return (htonl(addr_1) & mask) == (htonl(addr_2) & mask);
41 * Find out whether the peer name of a given fd belongs to an acl.
43 * \param fd File descriptor.
44 * \param acl The access control list.
46 * \return One if \a fd belongs to \a acl, zero otherwise.
48 static int acl_lookup(int fd, struct list_head *acl)
50 struct access_info *ai, *tmp;
51 struct sockaddr_storage ss;
52 socklen_t sslen = sizeof(ss);
53 struct in_addr v4_addr;
55 if (getpeername(fd, (struct sockaddr *)&ss, &sslen) < 0) {
56 PARA_ERROR_LOG("Can not determine peer address: %s\n", strerror(errno));
59 v4_addr = extract_v4_addr(&ss);
63 list_for_each_entry_safe(ai, tmp, acl, node)
64 if (v4_addr_match(v4_addr.s_addr, ai->addr.s_addr, ai->netmask))
71 * Add an entry to an access control list.
73 * \param acl The access control list.
74 * \param addr The address to add.
75 * \param netmask The netmask to use for this entry.
77 static void acl_add_entry(struct list_head *acl, struct in_addr addr,
80 struct access_info *ai = para_malloc(sizeof(struct access_info));
82 ai->netmask = netmask;
83 PARA_INFO_LOG("adding %s/%i to access list\n", inet_ntoa(ai->addr),
85 para_list_add(&ai->node, acl);
90 * Delete an entry from an access control list.
92 * \param acl The access control list.
93 * \param addr The address to delete.
94 * \param netmask The netmask of the entry to be removed from the list.
96 static void acl_del_entry(struct list_head *acl, struct in_addr addr,
99 struct access_info *ai, *tmp;
101 list_for_each_entry_safe(ai, tmp, acl, node) {
102 char *nad = para_strdup(inet_ntoa(ai->addr));
103 if (!strcmp(nad, inet_ntoa(addr)) &&
104 ai->netmask == netmask) {
105 PARA_NOTICE_LOG("removing %s/%i from access list\n",
115 * Compute a string containing the contents of an acl.
117 * \param acl The access control list.
119 * \return A string containing the contents of \a acl, or \p NULL
120 * if \a acl is empty.
122 char *acl_get_contents(struct list_head *acl)
124 struct access_info *ai, *tmp_ai;
127 list_for_each_entry_safe(ai, tmp_ai, acl, node) {
128 char *tmp = make_message("%s%s/%d ", ret? ret : "",
129 inet_ntoa(ai->addr), ai->netmask);
137 * Initialize an access control list.
139 * \param acl The list to initialize.
140 * \param acl_info An array of strings of the form ip/netmask.
141 * \param num The number of strings in \a acl_info.
143 void acl_init(struct list_head *acl, char * const *acl_info, int num)
148 for (i = 0; i < num; i++) {
149 char *arg = para_strdup(acl_info[i]);
150 char *p = strchr(arg, '/');
157 if (!inet_pton(AF_INET, arg, &addr))
160 if (netmask < 0 || netmask > 32)
162 acl_add_entry(acl, addr, netmask);
165 PARA_CRIT_LOG("syntax error: %s\n", acl_info[i]);
174 * Check whether the peer name of a given fd is allowed by an acl.
176 * \param fd File descriptor.
177 * \param acl The access control list.
178 * \param default_deny Whether \a acl is a whitelist.
180 * \return Positive if the peer of \a fd is permitted by \a acl, \p -E_ACL_PERM
183 int acl_check_access(int fd, struct list_head *acl, int default_deny)
185 int match = acl_lookup(fd, acl);
187 return (!match || default_deny) && (match || !default_deny)?
192 * Permit access for a range of IP addresses.
194 * \param addr The address to permit.
195 * \param netmask The netmask of the entry to be permitted.
196 * \param acl The access control list.
197 * \param default_deny Whether \a acl is a whitelist.
199 void acl_allow(struct in_addr addr, int netmask,
200 struct list_head *acl, int default_deny)
203 acl_add_entry(acl, addr, netmask);
205 acl_del_entry(acl, addr, netmask);
209 * Deny access for a range of IP addresses.
211 * \param addr The address to permit.
212 * \param netmask The netmask of the entry to be permitted.
213 * \param acl The access control list.
214 * \param default_deny Whether \a acl is a whitelist.
216 void acl_deny(struct in_addr addr, int netmask,
217 struct list_head *acl, int default_deny)
219 acl_allow(addr, netmask, acl, !default_deny);