struct security_handle;
+/*
+ * Overview
+ *
+ * The Security API consists of handles (also called connections), each of
+ * which represents a connection to a particular host. A handle is implemented
+ * by a driver. Each handle supports a packet-based communication protocol, as
+ * well as an arbitrary number of bidirectional tcp-like streams.
+ */
+
/*
* This is a type that gets passed to the security_recvpkt() and
- * security_connect() callbacks.
- * It details what the status of this callback is.
+ * security_connect() callbacks. It details what the status of this callback
+ * is.
+ */
+typedef enum {
+ S_OK, /* the pkt_t was received fine */
+ S_TIMEOUT, /* no pkt_t was received within the time specified in the
+ * timeout argument to security_recvpkt() */
+ S_ERROR, /* an error occurred during reception. Call security_geterror()
+ * for more information */
+} security_status_t;
+
+/*
+ * Drivers
*/
-typedef enum { S_OK, S_TIMEOUT, S_ERROR } security_status_t;
/*
* This structure defines a security driver. This driver abstracts
* mask this.
*/
typedef struct security_driver {
+
/*
- * The name of this driver, eg, "BSD", "BSDTCP", "KRB5", etc...
+ * The name of this driver, eg, "BSD", "BSDTCP", "KRB5", etc... This is
+ * used by security_getdriver() to associate a name with a driver type.
*/
const char *name;
/*
- * Connects a security handle, for this driver to a remote
- * host.
+ * This is the implementation of security_connect(). It actually sets up
+ * the connection, and then returns a structure describing the connection.
+ * The first element of this structure MUST be a security_handle_t, because
+ * it will be cast to that after it is passed up to the caller.
+ *
+ * The first argument is the host to connect to. The second argument is a
+ * function to call when a connection is made. The third argument is passed
+ * to the callback.
+ *
+ * The callback takes three arguments. The first is the caller supplied
+ * void pointer. The second is a newly allocated security handle. The third
+ * is a security_status_t flag indicating the success or failure of the
+ * operation.
*/
- void (*connect)(const char *,
- char *(*)(char *, void *),
- void (*)(void *, struct security_handle *, security_status_t),
- void *, void *);
+ void (*connect)(const char *, char *(*)(char *, void *),
+ void (*)(void *, struct security_handle *, security_status_t),
+ void *, void *);
/*
- * This form sets up a callback that returns new handles as
- * they are received. It takes an input and output file descriptor.
+ * This form sets up a callback that returns new handles as they are
+ * received. It is passed the input and output file descriptors and a
+ * callback. The callback takes a security handle argument and also an
+ * initial packet received for that handle.
*/
- void (*accept)(const struct security_driver *,
- char *(*)(char *, void *),
- int, int,
- void (*)(struct security_handle *, pkt_t *),
- void *);
+ void (*accept)(const struct security_driver *, char *(*)(char *, void *),
+ int, int, void (*)(struct security_handle *, pkt_t *), void *);
+
+ /* get the remote hostname */
+ char *(*get_authenticated_peer_name)(struct security_handle *handle);
/*
- * Frees up handles allocated by the previous
+ * Frees up handles allocated by the previous methods
*/
void (*close)(void *);
ssize_t (*sendpkt)(void *, pkt_t *);
/*
- * This creates an event in the event handler for receiving pkt_t's
- * on a security_handle. The given callback with the given arg
- * will be called when the driver determines that it has data
- * for that handle. The last argument is a timeout, in seconds.
- * This may be -1 to indicate no timeout.
+ * This creates an event in the event handler for receiving pkt_t's on a
+ * security_handle. The given callback will be called with the given arg
+ * when the driver determines that it has data for that handle. The last
+ * argument is a timeout, in seconds. This may be -1 to indicate no
+ * timeout. This method should assume that the caller will invoke
+ * event_loop
+ *
+ * If there was an error or timeout, this will be indicated in the status
+ * argument.
*
- * If there was an error or timeout, this will be indicated in
- * the status argument.
- *
* Only one recvpkt request can exist per handle.
*/
- void (*recvpkt)(void *, void (*)(void *, pkt_t *,
- security_status_t), void *, int);
+ void (*recvpkt)(void *, void (*)(void *, pkt_t *, security_status_t), void
+ *, int);
/*
- * Cancel an outstanding recvpkt request on a handle.
+ * Cancel an outstanding recvpkt request on a handle. Drivers should allow
+ * this to be run even if no recvpkt was scheduled, or if one was
+ * previously cancelled.
*/
void (*recvpkt_cancel)(void *);
/*
- * Get a stream given a security handle
+ * Get a stream given a security handle. This function returns a object
+ * describing the stream. The first member of this object MUST be a
+ * security_stream_t, because it will be cast to that.
*/
void *(*stream_server)(void *);
int (*stream_accept)(void *);
/*
- * Get a stream and connect it to a remote given a security handle
- * and a stream id.
+ * Get a stream and connect it to a remote given a security handle and a
+ * stream id. This function returns a object describing the stream. The
+ * first member of this object MUST be a security_stream_t, because it will
+ * be cast to that.
*/
void *(*stream_client)(void *, int);
int (*stream_auth)(void *);
/*
- * Return a numeric id for a stream.
+ * Return a numeric id for a stream. This is to be used by stream_client
+ * on the other end of the connection to connect to this stream.
*/
int (*stream_id)(void *);
int (*data_decrypt)(void *, void *, ssize_t, void **, ssize_t *);
} security_driver_t;
+/* Given a security type ("KRB4", "BSD", "SSH", etc), returns a pointer to that
+ * type's security_driver_t, or NULL if no driver exists. */
+const security_driver_t *security_getdriver(const char *);
+
+/*
+ * Handles
+ */
+
/*
* This structure is a handle to a connection to a host for transmission
* of protocol packets (pkt_t's). The underlying security type defines
char *error;
} security_handle_t;
-/*
- * This structure is a handle to a stream connection to a host for
- * transmission of random data such as dumps or index data.
+/* void security_connect(
+ * const security_driver_t *driver,
+ * const char *hostname,
+ * char *(*conf_fn)(char *, void *),
+ * void (*fn)(void *, security_handle_t *, security_status_t),
+ * void *arg,
+ * void *datap);
+ *
+ * Given a security driver, and a hostname, calls back with a security_handle_t
+ * that can be used to communicate with that host. The status arg to the
+ * callback is reflects the success of the request. Error messages can be had
+ * via security_geterror(). The conf_fn is used to determine configuration
+ * information, with its second argument being the datap. If conf_fn is NULL,
+ * no configuration information is available.
*/
-typedef struct security_stream {
- const security_driver_t *driver;
- char *error;
-} security_stream_t;
-
-
-const security_driver_t *security_getdriver(const char *);
-void security_handleinit(security_handle_t *, const security_driver_t *);
-void security_streaminit(security_stream_t *, const security_driver_t *);
-
-/* const char *security_geterror(security_handle_t *); */
-#define security_geterror(handle) ((handle)->error)
-void security_seterror(security_handle_t *, const char *, ...)
- G_GNUC_PRINTF(2,3);
-
-
-/* void security_connect(const security_driver_t *, const char *,
- char *(*)(char *, void *),
- void (*)(void *, security_handle_t *, security_status_t),
- void *,
- void *); */
#define security_connect(driver, hostname, conf_fn, fn, arg, datap) \
(*(driver)->connect)(hostname, conf_fn, fn, arg, datap)
-/* void security_accept(const security_driver_t *,
- char *(*)(char *, void *), int, int,
- void (*)(security_handle_t *, pkt_t *), void *); */
+/* void security_accept(
+ * const security_driver_t *driver,
+ * char *(*conf_fn)(char *, void *),
+ * int in,
+ * int out,
+ * void (*fn)(security_handle_t *, pkt_t *),
+ * void *datap);
+ *
+ * Given a security driver, an input file descriptor, and an output file
+ * descriptor, and a callback, when new connections are detected on the given
+ * file descriptors, the function is called with a newly created security
+ * handle and the initial packet received. This is amandad's interface for
+ * accepting incoming connections from the Amanda server. The file descriptors
+ * are typically 0 and 1 (stdin/stdout). This function uses the event
+ * interface, and only works properly when event_loop() is called later in the
+ * program.
+ */
#define security_accept(driver, conf_fn, in, out, fn, datap) \
(*(driver)->accept)(driver, conf_fn, in, out, fn, datap)
+
+/* char *security_get_authenticated_peer_name(
+ * security_handle_t *handle);
+ *
+ * Returns the fully qualified, authenticated hostname of the peer, or
+ * "localhost" for a local system. The string is statically allocated and need
+ * not be freed. The string will never be NULL, but may be an empty string if
+ * the remote identity is not known, not defined, or could not be
+ * authenticated.
+ */
+#define security_get_authenticated_peer_name(handle) \
+ (*(handle)->driver->get_authenticated_peer_name)(handle)
+
+/* Closes a security stream created by a security_connect() or
+ * security_accept() and frees up resources associated with it. */
void security_close(security_handle_t *);
-/* ssize_t security_sendpkt(security_handle_t *, const pkt_t *); */
+/* ssize_t security_sendpkt(security_handle_t *, const pkt_t *);
+ *
+ * Transmits a pkt_t over a security handle. Returns 0 on success, or negative
+ * on error. A descriptive error message can be obtained via
+ * security_geterror(). */
#define security_sendpkt(handle, pkt) \
(*(handle)->driver->sendpkt)(handle, pkt)
-/* void security_recvpkt(security_handle_t *,
- void (*)(void *, pkt_t *, security_status_t), void *, int); */
+/* void security_recvpkt(
+ * security_handle_t *handle,
+ * void (*fn)(void *, pkt_t *, security_status_t),
+ * void *arg,
+ * int timeout);
+ *
+ * Requests that when incoming packets arrive for this handle, the given
+ * function is called with the given argument, the received packet, and the
+ * status of the reception. If a packet does not arrive within the number of
+ * seconds specified in the 'timeout' argument, RECV_TIMEOUT is passed in the
+ * status argument of the timeout. On receive error, the callback's status
+ * argument will be set to RECV_ERROR. An error message can be retrieved via
+ * security_geterror(). On successful reception, RECV_OK will be passed in the
+ * status argument, and the pkt argument will point to a valid packet. This
+ * function uses the event interface. Callbacks will only be generated when
+ * event_loop() is called. */
#define security_recvpkt(handle, fn, arg, timeout) \
(*(handle)->driver->recvpkt)(handle, fn, arg, timeout)
-/* void security_recvpkt_cancel(security_handle_t *); */
+/* void security_recvpkt_cancel(security_handle_t *);
+ *
+ * Cancels a previous recvpkt request for this handle. */
#define security_recvpkt_cancel(handle) \
(*(handle)->driver->recvpkt_cancel)(handle)
-/* const char *security_stream_geterror(security_stream_t *); */
+/* const char *security_geterror(security_handle_t *);
+ *
+ * Returns a descriptive error message for the last error condition on this
+ * handle. */
+#define security_geterror(handle) ((handle)->error)
+
+/* Sets the string that security_geterror() returns. For use by security
+ * drivers. */
+void security_seterror(security_handle_t *, const char *, ...)
+ G_GNUC_PRINTF(2,3);
+
+/* Initializes a security_handle_t. This is meant to be called only by security
+ * drivers to initialize the common part of a newly allocated
+ * security_handle_t. */
+void security_handleinit(security_handle_t *, const security_driver_t *);
+
+/*
+ * Streams
+ */
+
+/*
+ * This structure is a handle to a stream connection to a host for
+ * transmission of random data such as dumps or index data.
+ */
+typedef struct security_stream {
+ const security_driver_t *driver;
+ char *error;
+} security_stream_t;
+
+/* Initializes a security_stream_t. This is meant to be called only by security
+ * drivers to initialize the common part of a newly allocated
+ * security_stream_t. */
+void security_streaminit(security_stream_t *, const security_driver_t *);
+
+/* const char *security_stream_geterror(security_stream_t *);
+ *
+ * Returns a descriptive error message for the last error condition on this
+ * stream. */
#define security_stream_geterror(stream) ((stream)->error)
+
+/* Sets the string that security_stream_geterror() returns. */
void security_stream_seterror(security_stream_t *, const char *, ...)
G_GNUC_PRINTF(2,3);
-/* security_stream_t *security_stream_server(security_handle_t *); */
+/* security_stream_t *security_stream_server(security_handle_t *);
+ *
+ * Creates the server end of a security stream, and will prepare to receive a
+ * connection from the host on the other end of the security handle passed.
+ * Returns a security_stream_t on success, and NULL on error. Error messages
+ * can be obtained by calling security_geterror() on the security handle
+ * associated with this stream. */
#define security_stream_server(handle) \
(*(handle)->driver->stream_server)(handle)
-/* int security_stream_accept(security_stream_t *); */
+/* int security_stream_accept(security_stream_t *);
+ *
+ * Given a security stream created by security_stream_server, blocks until a
+ * connection is made from the remote end. After calling stream_server,
+ * stream_accept must be called on the stream before it is fully connected.
+ * Returns 0 on success, and -1 on error. Error messages can be obtained by
+ * calling security_stream_geterror().
+ */
#define security_stream_accept(stream) \
(*(stream)->driver->stream_accept)(stream)
-/* security_stream_t *security_stream_client(security_handle_t *, int); */
+/* security_stream_t *security_stream_client(security_handle_t *, int);
+ *
+ * Creates the client end of a security stream, and connects it to the machine
+ * on the other end of the security handle. The 'id' argument identifies which
+ * stream on the other end to connect to, and should have come from
+ * security_stream_id on the other end of the connection. Returns a
+ * security_stream_t on success, and NULL on error. Error messages can be
+ * obtained by calling security_geterror() on the security handle associated
+ * with this stream. */
#define security_stream_client(handle, id) \
(*(handle)->driver->stream_client)(handle, id)
+/* Closes a security stream and frees up resources associated with it. */
void security_stream_close(security_stream_t *);
-/* int security_stream_auth(security_stream_t *); */
+/* int security_stream_auth(security_stream_t *);
+ *
+ * Authenticate a connected security stream. This should be called by the
+ * target after security_stream_accept returns successfully, and by the client
+ * after security_stream_connect returns successfullly. Returns 0 on success,
+ * and -1 on error. Error messages can be obtained by calling
+ * security_stream_geterror().
+ */
#define security_stream_auth(stream) \
(*(stream)->driver->stream_auth)(stream)
-/* int security_stream_id(security_stream_t *); */
+/* int security_stream_id(security_stream_t *);
+ *
+ * Returns an identifier which can be used to connect to this security stream
+ * with security_stream_client(). Typical usage is for one end of a connection
+ * to create a stream with security_stream_server(), and then transmit the id
+ * for that stream to the other side. The other side will then connect to that
+ * id with security_stream_client(). */
#define security_stream_id(stream) \
(*(stream)->driver->stream_id)(stream)
-/* int security_stream_write(security_stream_t *, const void *, size_t); */
+/* int security_stream_write(security_stream_t *, const void *, size_t);
+ *
+ * Writes a chunk of data to the security stream. Returns 0 on success, or
+ * negative on error. Error messages can be obtained by calling
+ * security_stream_geterror().
+ */
#define security_stream_write(stream, buf, size) \
(*(stream)->driver->stream_write)(stream, buf, size)
-/* void security_stream_read(security_stream_t *,
- void (*)(void *, void *, size_t), void *); */
+/* void security_stream_read(
+ * security_stream_t *stream,
+ * void (*fn)(void *, void *, size_t),
+ * void *arg);
+
+ * Requests that when data is ready to be read on this stream, the given
+ * function is called with the given arg, a buffer full of data, and the size
+ * of that buffer. On error, the bufsize will be negative. An error message can
+ * be retrieved by calling security_stream_geterror(). This function uses the
+ * event interface. Callbacks will only be generated while in event_loop(). */
#define security_stream_read(stream, fn, arg) \
(*(stream)->driver->stream_read)(stream, fn, arg)
-/* void security_stream_read_sync(security_stream_t *, void *); */
+/* void security_stream_read_sync(security_stream_t *, void **);
+ *
+ * Return a buffer of data read from the stream. This function will block until
+ * something can be read, but other event will be fired. A pointer to the data
+ * is returned in *buf and the size of the buffer is returned. On error, the
+ * size will be negative. An error message can be retrieved by calling
+ * security_stream_geterror(). This function uses the event interface. */
#define security_stream_read_sync(stream, buf) \
(*(stream)->driver->stream_read_sync)(stream, buf)
-/* void security_stream_read_cancel(security_stream_t *); */
+/* void security_stream_read_cancel(security_stream_t *);
+ *
+ * Cancels a previous read request. */
#define security_stream_read_cancel(stream) \
(*(stream)->driver->stream_read_cancel)(stream)
+/* void security_close_connection(security_handle_t *, hostname *);
+ *
+ * Close a security handle, freeing associated resources. The hostname
+ * argument is ignored. */
#define security_close_connection(handle, hostname) \
(*(handle)->driver->close_connection)(handle, hostname)
+
#endif /* SECURITY_H */
projects / debian / amanda / blobdiff