2 * Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file acl.c Access control lists for paraslash senders. */
9 #include <netinet/in.h>
10 #include <sys/socket.h>
12 #include <arpa/inet.h>
24 * Describes one entry in the blacklist/whitelist of a paraslash sender.
27 /** The address to be black/whitelisted. */
29 /** The netmask for this entry. */
31 /** The position of this entry in the acl. */
32 struct list_head node;
36 * Return true if addr_1 matches addr_2 in the first `netmask' bits.
38 static int v4_addr_match(uint32_t addr_1, uint32_t addr_2, uint8_t netmask)
43 mask <<= (32 - netmask);
44 return (htonl(addr_1) & mask) == (htonl(addr_2) & mask);
48 * Find out whether the peer name of a given fd belongs to an acl.
50 * \param fd File descriptor.
51 * \param acl The access control list.
53 * \return One if \a fd belongs to \a acl, zero otherwise.
55 static int acl_lookup(int fd, struct list_head *acl)
57 struct access_info *ai, *tmp;
58 struct sockaddr_storage ss;
59 socklen_t sslen = sizeof(ss);
60 struct in_addr v4_addr;
62 if (getpeername(fd, (struct sockaddr *)&ss, &sslen) < 0) {
63 PARA_ERROR_LOG("Can not determine peer address: %s\n", strerror(errno));
66 extract_v4_addr(&ss, &v4_addr);
70 list_for_each_entry_safe(ai, tmp, acl, node)
71 if (v4_addr_match(v4_addr.s_addr, ai->addr.s_addr, ai->netmask))
78 * Add an entry to an access control list.
80 * \param acl The access control list.
81 * \param addr The address to add.
82 * \param netmask The netmask to use for this entry.
84 static void acl_add_entry(struct list_head *acl, char *addr, int netmask)
86 struct access_info *ai = para_malloc(sizeof(struct access_info));
88 inet_pton(AF_INET, addr, &ai->addr);
89 ai->netmask = netmask;
90 PARA_INFO_LOG("adding %s/%i to access list\n", addr, ai->netmask);
91 para_list_add(&ai->node, acl);
95 * Delete an entry from an access control list.
97 * \param acl The access control list.
98 * \param addr The address to delete.
99 * \param netmask The netmask of the entry to be removed from the list.
101 static void acl_del_entry(struct list_head *acl, char *addr, unsigned netmask)
103 struct access_info *ai, *tmp;
104 struct in_addr to_delete;
106 inet_pton(AF_INET, addr, &to_delete);
108 list_for_each_entry_safe(ai, tmp, acl, node) {
110 if (v4_addr_match(to_delete.s_addr, ai->addr.s_addr,
111 PARA_MIN(netmask, ai->netmask))) {
112 PARA_NOTICE_LOG("removing %s/%i from access list\n",
121 * Compute a string containing the contents of an acl.
123 * \param acl The access control list.
125 * \return A string containing the contents of \a acl, or \p NULL
126 * if \a acl is empty.
128 char *acl_get_contents(struct list_head *acl)
130 struct access_info *ai, *tmp_ai;
133 list_for_each_entry_safe(ai, tmp_ai, acl, node) {
134 char *tmp = make_message("%s%s/%d ", ret? ret : "",
135 inet_ntoa(ai->addr), ai->netmask);
143 * Initialize an access control list.
145 * \param acl The list to initialize.
146 * \param acl_info An array of strings of the form ip/netmask.
147 * \param num The number of strings in \a acl_info.
149 void acl_init(struct list_head *acl, char * const *acl_info, int num)
155 for (i = 0; i < num; i++)
156 if (parse_cidr(acl_info[i], addr, sizeof(addr), &mask) == NULL)
157 PARA_CRIT_LOG("ACL syntax error: %s, ignoring\n",
160 acl_add_entry(acl, addr, mask);
164 * Check whether the peer name of a given fd is allowed by an acl.
166 * \param fd File descriptor.
167 * \param acl The access control list.
168 * \param default_deny Whether \a acl is a whitelist.
170 * \return Positive if the peer of \a fd is permitted by \a acl, \p -E_ACL_PERM
173 int acl_check_access(int fd, struct list_head *acl, int default_deny)
175 int match = acl_lookup(fd, acl);
177 return (!match || default_deny) && (match || !default_deny)?
182 * Permit access for a range of IP addresses.
184 * \param addr The address to permit.
185 * \param netmask The netmask of the entry to be permitted.
186 * \param acl The access control list.
187 * \param default_deny Whether \a acl is a whitelist.
189 void acl_allow(char *addr, int netmask,
190 struct list_head *acl, int default_deny)
193 acl_add_entry(acl, addr, netmask);
195 acl_del_entry(acl, addr, netmask);
199 * Deny access for a range of IP addresses.
201 * \param addr The address to deny.
202 * \param netmask The netmask of the entry to be denied.
203 * \param acl The access control list.
204 * \param default_deny Whether \a acl is a whitelist.
206 void acl_deny(char *addr, int netmask,
207 struct list_head *acl, int default_deny)
209 acl_allow(addr, netmask, acl, !default_deny);