Implement access control for the dccp sender.

[paraslash.git] / acl.c

diff --git a/acl.c b/acl.c
index 3a30bd453306cfc65c0dc0605af9e9015b88f1d6..fb9cded668dd15baed93c548dfadc64085f98fc3 100644 (file)
--- a/acl.c
+++ b/acl.c
@@ -37,7 +37,15 @@ static int v4_addr_match(uint32_t addr_1, uint32_t addr_2, uint8_t netmask)
        return (htonl(addr_1) & mask) == (htonl(addr_2) & mask);
 }
 
-int host_in_acl(int fd, struct list_head *acl)
+/**
+ * Find out whether the peer name of a given fd belongs to an acl.
+ *
+ * \param fd File descriptor.
+ * \param acl The access control list.
+ *
+ * \return One if \a fd belongs to \a acl, zero otherwise.
+ */
+static int acl_lookup(int fd, struct list_head *acl)
 {
        struct access_info *ai, *tmp;
        struct sockaddr_storage ss;
@@ -59,7 +67,14 @@ no_match:
        return 0;
 }
 
-void add_acl_entry(struct list_head *acl, struct in_addr addr,
+/**
+ * Add an entry to an access control list.
+ *
+ * \param acl The access control list.
+ * \param addr The address to add.
+ * \param netmask The netmask to use for this entry.
+ */
+static void acl_add_entry(struct list_head *acl, struct in_addr addr,
                int netmask)
 {
        struct access_info *ai = para_malloc(sizeof(struct access_info));
@@ -71,7 +86,14 @@ void add_acl_entry(struct list_head *acl, struct in_addr addr,
 }
 
 
-void del_acl_entry(struct list_head *acl, struct in_addr addr,
+/**
+ * Delete an entry from an access control list.
+ *
+ * \param acl The access control list.
+ * \param addr The address to delete.
+ * \param netmask The netmask of the entry to be removed from the list.
+ */
+static void acl_del_entry(struct list_head *acl, struct in_addr addr,
                int netmask)
 {
        struct access_info *ai, *tmp;
@@ -89,7 +111,15 @@ void del_acl_entry(struct list_head *acl, struct in_addr addr,
        }
 }
 
-char *get_acl_contents(struct list_head *acl)
+/**
+ * Compute a string containing the contents of an acl.
+ *
+ * \param acl The access control list.
+ *
+ * \return A string containing the contents of \a acl, or \p NULL
+ * if \a acl is empty.
+ */
+char *acl_get_contents(struct list_head *acl)
 {
        struct access_info *ai, *tmp_ai;
        char *ret = NULL;
@@ -103,7 +133,14 @@ char *get_acl_contents(struct list_head *acl)
        return ret;
 }
 
-void init_acl(struct list_head *acl, char * const *acl_info, int num)
+/**
+ * Initialize an access control list.
+ *
+ * \param acl The list to initialize.
+ * \param acl_info An array of strings of the form ip/netmask.
+ * \param num The number of strings in \a acl_info.
+ */
+void acl_init(struct list_head *acl, char * const *acl_info, int num)
 {
        int i;
 
@@ -122,7 +159,7 @@ void init_acl(struct list_head *acl, char * const *acl_info, int num)
                netmask = atoi(++p);
                if (netmask < 0 || netmask > 32)
                        goto err;
-               add_acl_entry(acl, addr, netmask);
+               acl_add_entry(acl, addr, netmask);
                goto success;
 err:
                PARA_CRIT_LOG("syntax error: %s\n", acl_info[i]);
@@ -132,3 +169,52 @@ success:
        }
 }
 
+
+/**
+ * Check whether the peer name of a given fd is allowed by an acl.
+ *
+ * \param fd File descriptor.
+ * \param acl The access control list.
+ * \param default_deny Whether \a acl is a whitelist.
+ *
+ * \return Positive if the peer of \a fd is permitted by \a acl, \p -E_ACL_PERM
+ * otherwise.
+ */
+int acl_check_access(int fd, struct list_head *acl, int default_deny)
+{
+       int match = acl_lookup(fd, acl);
+
+       return (!match || default_deny) && (match || !default_deny)?
+               1 : -E_ACL_PERM;
+}
+
+/**
+ * Permit access for a range of IP addresses.
+ *
+ * \param addr The address to permit.
+ * \param netmask The netmask of the entry to be permitted.
+ * \param acl The access control list.
+ * \param default_deny Whether \a acl is a whitelist.
+ */
+void acl_allow(struct in_addr addr, int netmask,
+               struct list_head *acl, int default_deny)
+{
+       if (default_deny)
+               acl_add_entry(acl, addr, netmask);
+       else
+               acl_del_entry(acl, addr, netmask);
+}
+
+/**
+ * Deny access for a range of IP addresses.
+ *
+ * \param addr The address to permit.
+ * \param netmask The netmask of the entry to be permitted.
+ * \param acl The access control list.
+ * \param default_deny Whether \a acl is a whitelist.
+ */
+void acl_deny(struct in_addr addr, int netmask,
+               struct list_head *acl, int default_deny)
+{
+       acl_allow(addr, netmask, acl, !default_deny);
+}