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unix_writer.h000064400000005523150422026360007301 0ustar00/*
 * Copyright (c) 2014 by Farsight Security, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */

#ifndef FSTRM_UNIX_WRITER_H
#define FSTRM_UNIX_WRITER_H

/**
 * \defgroup fstrm_unix_writer fstrm_unix_writer
 *
 * `fstrm_unix_writer` is an interface for opening an \ref fstrm_writer object
 * that is backed by I/O on a stream-oriented (`SOCK_STREAM`) Unix socket.
 *
 * @{
 */

/**
 * Initialize an `fstrm_unix_writer_options` object, which is needed to
 * configure the socket path to be opened by the writer.
 *
 * \return
 *	`fstrm_unix_writer_options` object.
 */
struct fstrm_unix_writer_options *
fstrm_unix_writer_options_init(void);

/**
 * Destroy an `fstrm_unix_writer_options` object.
 * 
 * \param uwopt
 *	Pointer to `fstrm_unix_writer_options` object.
 */
void
fstrm_unix_writer_options_destroy(
	struct fstrm_unix_writer_options **uwopt);

/**
 * Set the `socket_path` option. This is a filesystem path that will be
 * connected to as an `AF_UNIX` socket.
 *
 * \param uwopt
 *	`fstrm_unix_writer_options` object.
 * \param socket_path
 *	The filesystem path to the `AF_UNIX` socket.
 */
void
fstrm_unix_writer_options_set_socket_path(
	struct fstrm_unix_writer_options *uwopt,
	const char *socket_path);

/**
 * Initialize the `fstrm_writer` object. Note that the `AF_UNIX` socket will not
 * actually be opened until a subsequent call to fstrm_writer_open().
 *
 * \param uwopt
 *	`fstrm_unix_writer_options` object. Must be non-NULL, and have the
 *	`socket_path` option set.
 * \param wopt
 *	`fstrm_writer_options` object. May be NULL, in which chase default
 *	values will be used.
 *
 * \return
 *	`fstrm_writer` object.
 * \retval
 *	NULL on failure.
 */
struct fstrm_writer *
fstrm_unix_writer_init(
	const struct fstrm_unix_writer_options *uwopt,
	const struct fstrm_writer_options *wopt);

/**@}*/

#endif /* FSTRM_UNIX_WRITER_H */
reader.h000064400000017734150422026360006173 0ustar00/*
 * Copyright (c) 2014 by Farsight Security, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */

#ifndef FSTRM_READER_H
#define FSTRM_READER_H

/**
 * \defgroup fstrm_reader fstrm_reader
 *
 * `fstrm_reader` is an interface for reading Frame Streams data from a byte
 * stream. The underlying byte stream I/O operations are abstracted by the
 * \ref fstrm_rdwr interface. Thus, the `fstrm_reader` interface can be used to
 * read Frame Streams data from any source whose read/write operations are
 * wrapped by an `fstrm_rdwr` object.
 *
 * Some basic `fstrm_reader` implementations are already provided in the `fstrm`
 * library. See fstrm_file_reader_init() to create an `fstrm_reader` object that
 * reads Frame Streams data from a regular file.
 *
 * @{
 */

/**
 * The default `max_frame_size` value.
 */
#define FSTRM_READER_MAX_FRAME_SIZE_DEFAULT	1048576

/**
 * Initialize an `fstrm_reader_options` object.
 *
 * \return
 *	`fstrm_reader_options` object.
 */
struct fstrm_reader_options *
fstrm_reader_options_init(void);

/**
 * Destroy an `fstrm_reader_options` object.
 *
 * \param ropt
 *	Pointer to `fstrm_reader_options` object.
 */
void
fstrm_reader_options_destroy(
	struct fstrm_reader_options **ropt);

/**
 * Add a "Content Type" value to the set of content types accepted by the
 * `fstrm_reader`. This function makes a copy of the provided string. This
 * function may be called multiple times, in which case multiple "Content Type"
 * values will be accepted by the reader.
 *
 * If the reader has no content types set, it will accept any content type.
 *
 * \param ropt
 *	`fstrm_reader_options` object.
 * \param content_type
 *	The "Content Type" string to copy. Note that this string is not
 *	NUL-terminated and may contain embedded NULs.
 * \param len_content_type
 *	The number of bytes in `content_type`.
 *
 * \retval #fstrm_res_success
 *	The "Content Type" field was successfully added.
 * \retval #fstrm_res_failure
 *	The "Content Type" string is too long.
 */
fstrm_res
fstrm_reader_options_add_content_type(
	struct fstrm_reader_options *ropt,
	const void *content_type,
	size_t len_content_type);

/**
 * Set the maximum frame size that the reader is willing to accept. This
 * enforces an upper limit on the amount of memory used to buffer incoming data
 * from the reader's byte stream.
 *
 * If this option is not set, it defaults to
 * #FSTRM_READER_MAX_FRAME_SIZE_DEFAULT.
 *
 * \param ropt
 *	`fstrm_reader_options` object.
 * \param max_frame_size
 *	The maximum frame size value.
 *
 * \retval #fstrm_res_success
 *	The `max_frame_size` value was successfully set.
 * \retval #fstrm_res_failure
 *	The `max_frame_size` value was too large or too small.
 */
fstrm_res
fstrm_reader_options_set_max_frame_size(
	struct fstrm_reader_options *ropt,
	size_t max_frame_size);

/**
 * Initialize a new `fstrm_reader` object based on an underlying `fstrm_rdwr`
 * object and an `fstrm_reader_options` object.
 *
 * The underlying `fstrm_rdwr` object MUST have a `read` method. It MAY
 * optionally have a `write` method, in which case the stream will be treated as
 * a bi-directional, handshaked stream. Otherwise, if there is no `write` method
 * the stream will be treated as a uni-directional stream.
 *
 * This function is useful for implementing functions that return new types of
 * `fstrm_reader` objects, such as fstrm_file_reader_init().
 *
 * After a successful call to this function, the ownership of the `fstrm_rdwr`
 * object passes from the caller to the `fstrm_reader` object. The caller
 * should perform no further calls on the `fstrm_rdwr` object. The `fstrm_rdwr`
 * object will be cleaned up on a call to fstrm_reader_destroy().
 *
 * \param ropt
 *	`fstrm_reader_options` object. May be NULL, in which case default values
 *	will be used.
 *
 * \param rdwr
 *	Pointer to `fstrm_rdwr` object. Must be non-NULL. The `fstrm_rdwr`
 *	object must have a `read` method, and may optionally have a `write`
 *	method.
 *
 * \return
 *	`fstrm_reader` object.
 * \retval
 *	NULL on failure.
 */
struct fstrm_reader *
fstrm_reader_init(
	const struct fstrm_reader_options *ropt,
	struct fstrm_rdwr **rdwr);

/**
 * Destroy an `fstrm_reader` object. This implicitly calls fstrm_reader_close()
 * if necessary.
 *
 * \param r
 *	Pointer to `fstrm_reader` object.
 *
 * \retval #fstrm_res_success
 * \retval #fstrm_res_failure
 */
fstrm_res
fstrm_reader_destroy(struct fstrm_reader **r);

/**
 * Open an `fstrm_reader` object and prepare it to read data.
 *
 * This checks that the content type in the byte stream, if specified, matches
 * one of the content types specified in the `fstrm_reader_options` object used
 * to initialize the `fstrm_reader` object.
 *
 * This function may fail if there was an underlying problem opening the input
 * stream.
 *
 * \param r
 *	`fstrm_reader` object.
 *
 * \retval #fstrm_res_success
 * \retval #fstrm_res_failure
 */
fstrm_res
fstrm_reader_open(struct fstrm_reader *r);

/**
 * Close an `fstrm_reader` object. Once it has been closed, no data frames may
 * subsequently be read.
 *
 * Calling this function is optional; it may be implicitly invoked by a call to
 * fstrm_reader_destroy().
 *
 * \param r
 *	`fstrm_reader` object.
 *
 * \retval #fstrm_res_success
 * \retval #fstrm_res_failure
 */
fstrm_res
fstrm_reader_close(struct fstrm_reader *r);

/**
 * Read a data frame from an `fstrm_reader` object. This frame is held in an
 * internal buffer owned by the `fstrm_reader` object and should not be modified
 * by the caller. The contents of this buffer will be overwritten by a
 * subsequent call to fstrm_reader_read().
 *
 * This function implicitly calls fstrm_reader_open() if necessary.
 *
 * \param r
 *	`fstrm_reader` object.
 * \param[out] data
 *	Pointer to buffer containing the data frame payload.
 * \param[out] len_data
 *	The number of bytes available in `data`.
 *
 * \retval #fstrm_res_success
 *	A data frame was successfully read.
 * \retval #fstrm_res_stop
 *	The end of the stream has been reached.
 * \retval #fstrm_res_failure
 */
fstrm_res
fstrm_reader_read(
	struct fstrm_reader *r,
	const uint8_t **data,
	size_t *len_data);

/**
 * Obtain a pointer to an `fstrm_control` object used during processing. Objects
 * returned by this function are owned by the `fstrm_reader` object and must not
 * be modified by the caller. After a call to fstrm_reader_destroy() these
 * pointers will no longer be valid.
 *
 * For example, this function can be used to obtain a pointer to the START
 * control frame, which can be queried to see which "Content Type" was
 * negotiated during the opening of the reader.
 *
 * This function implicitly calls fstrm_reader_open() if necessary.
 *
 * \param r
 *	`fstrm_reader` object.
 * \param type
 *	Which control frame to return.
 * \param[out] control
 *	The `fstrm_control` object.
 *
 * \retval #fstrm_res_success
 *	If an `fstrm_control` object was returned.
 * \retval #fstrm_res_failure
 */
fstrm_res
fstrm_reader_get_control(
	struct fstrm_reader *r,
	fstrm_control_type type,
	const struct fstrm_control **control);

/**@}*/

#endif /* FSTRM_READER_H */
control.h000064400000050207150422026360006401 0ustar00/*
 * Copyright (c) 2014 by Farsight Security, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */

#ifndef FSTRM_CONTROL_H
#define FSTRM_CONTROL_H

/**
 * \defgroup fstrm_control fstrm_control
 *
 * `fstrm_control` is an interface for encoding and decoding Frame Streams
 * control frames.
 *
 * Two types of frames are possible in a Frame Streams byte stream: **data
 * frames** and **control frames**. Both are variable length byte sequences
 * prefixed by a 32-bit big endian unsigned integer (the **frame length**)
 * specifying the length of the following byte sequence. If this frame length
 * value is greater than zero, the **frame length** specifies the **data frame
 * length**, and a data frame follows it. If the frame length is zero (i.e., it
 * is the four byte sequence `00 00 00 00`), this is an **escape sequence**,
 * which means that a control frame follows. The control frame itself is
 * prefixed by a 32-bit big endian unsigned integer (the **control frame
 * length**) specifying the length of the following **control frame payload**.
 *
 * There are two types of control frames used for uni-directional streams:
 * `START` and `STOP`. These control frame types bracket the stream of data
 * frames. `START` indicates the beginning of the stream and communicates
 * metadata about the stream to follow, and `STOP` indicates the end of the
 * stream.
 *
 * Bi-directional streams make use of three additional control frame types:
 * `READY`, `ACCEPT`, and `FINISH`. These control frame types are used in a
 * simple handshake protocol between sender and receiver.
 *
 * A uni-directional Frame Streams byte stream normally consists of the
 * following:
 *
 * 1. The `START` control frame.
 * 2. A sequence of zero or more data frames or control frames that are not of
 *      the control frame types `START`, `STOP`, `ACCEPT`, `READY`, or
 *      `FINISH`.
 * 3. The `STOP` control frame.
 *
 * The `START` and `STOP` control frames are not optional. The `START` control
 * frame must appear at the beginning of the byte stream, and the `STOP` control
 * frame must appear at the end of the byte stream. (If the byte stream has an
 * end.) `START` control frames must not appear anywhere other than at the
 * beginning of the byte stream, and `STOP` control frames must not appear
 * anywhere other than at the end of the byte stream. Only one `START` control
 * frame and only one `STOP` control frame may appear in a Frame Streams byte
 * stream.
 *
 * Control frames may optionally include zero or more **control frame fields**.
 * There is currently one type of control frame field defined: `CONTENT_TYPE`.
 * This field specifies a variable length byte sequence describing the encoding
 * of data frames that appear in the Frame Streams byte stream. This field is
 * used by cooperating programs to unambiguously identify how to interpret the
 * data frames in a particular Frame Streams byte stream. For instance, this
 * field may specify a particular schema to use to interpret the data frames
 * appearing in the byte stream. Zero, one, or more `CONTENT_TYPE` fields may
 * appear in `READY` or `ACCEPT` control frames. Zero or one `CONTENT_TYPE`
 * fields may appear in `START` control frames. No `CONTENT_TYPE` fields may
 * appear in `STOP` or `FINISH` control frames.
 *
 * A uni-directional Frame Streams encoder would normally produce a byte stream
 * as follows:
 *
 * 1. Write the `START` **control frame**.
 *      + At the start of the byte stream, write the four byte **escape
 *      sequence** `00 00 00 00` that precedes control frames.
 *      + Write the **control frame length** as a 32-bit big endian unsigned
 *      integer.
 *      + Write the **control frame payload**. It must be a `START` control
 *      frame. It may optionally specify a `CONTENT_TYPE` field.
 * 2. Write zero or more **data frames**.
 * 3. Write the `STOP` **control frame**.
 *      + At the start of the byte stream, write the four byte **escape
 *      sequence** `00 00 00 00` that precedes control frames.
 *      + Write the **control frame length** as a 32-bit big endian unsigned
 *      integer.
 *      + Write the **control frame payload**. It must be a `STOP` control
 *      frame.
 *
 * A uni-directional Frame Streams decoder would normally process the byte
 * stream as follows:
 *
 * 1. Read the `START` control frame.
 *      + At the start of the byte stream, read the four byte **escape
 *      sequence** `00 00 00 00` that precedes control frames.
 *      + Read the 32-bit big endian unsigned integer specifying the **control
 *      frame length**.
 *      + Decode the **control frame payload**. It must be a `START` control
 *      frame. It may optionally specify a `CONTENT_TYPE` field.
 * 2. Repeatedly read data frames or control frames following the `START`
 * control frame.
 *      + Read the **frame length**, a 32-bit big endian unsigned integer.
 *      + If the **frame length** is zero, a control frame follows:
 *              + Read the 32-bit big endian unsigned integer specifying the
 *              **control frame length**.
 *              + Decode the **control frame payload**. If it is a `STOP`
 *              control frame, the end of the Frame Streams byte stream has
 *              occurred, and no frames follow. Break out of the decoding loop
 *              and halt processing. (`READY`, `ACCEPT`, `START`, and `FINISH`
 *              may not occur here. For forward compatibility, control frames of
 *              types other than the types `READY`, `ACCEPT`, `START`, `STOP`,
 *              and `FINISH` must be ignored here. No control frames specified
 *              in the future may alter the encoding of succeeding frames.)
 *      + If the **frame length** is non-zero, it specifies the number of bytes
 *      in the following **data frame**. Consume these bytes from the byte
 *      stream.
 *
 * The functions fstrm_control_encode() and fstrm_control_decode() are provided
 * to encode and decode control frames. See the detailed descriptions of those
 * functions for code examples showing their usage.
 *
 * @{
 */

/**
 * The maximum length in bytes of an "Accept", "Start", or "Stop" control frame
 * payload. This excludes the escape sequence and the control frame length.
 */
#define FSTRM_CONTROL_FRAME_LENGTH_MAX			512

/**
 * The maximum length in bytes of a "Content Type" control frame field payload.
 * This excludes the field type and payload length.
 */
#define FSTRM_CONTROL_FIELD_CONTENT_TYPE_LENGTH_MAX	256

/**
 * Control frame types.
 */
typedef enum {
	/** Control frame type value for "Accept" control frames. */
	FSTRM_CONTROL_ACCEPT	= 0x01,

	/** Control frame type value for "Start" control frames. */
	FSTRM_CONTROL_START	= 0x02,

	/** Control frame type value for "Stop" control frames. */
	FSTRM_CONTROL_STOP	= 0x03,

	/** Control frame type value for "Ready" control frames. */
	FSTRM_CONTROL_READY	= 0x04,

	/** Control frame type value for "Finish" control frames. */
	FSTRM_CONTROL_FINISH	= 0x05,
} fstrm_control_type;

/**
 * Control frame field types. These are optional fields that can appear in
 * control frames.
 */
typedef enum {
	/**
	 * Control frame field type value for the "Content Type" control frame
	 * option.
	 */
	FSTRM_CONTROL_FIELD_CONTENT_TYPE	= 0x01,
} fstrm_control_field;

/**
 * Flags for controlling the behavior of the encoding and decoding functions.
 */
typedef enum {
	/**
	 * Set to control whether to include the control frame header in
	 * encoding/decoding operations.
	 *
	 * Causes fstrm_control_encode() and fstrm_control_encoded_size() to
	 * include the control frame header containing the escape sequence and
	 * control frame payload length in the encoded output. Otherwise, only
	 * the control frame payload itself is encoded.
	 *
	 * Tells fstrm_control_decode() that the input buffer to be decoded
	 * begins with the control frame header containing the escape sequence
	 * and control frame payload length. (Note that this requires the caller
	 * to peek at the input buffer to calculate the right buffer length.)
	 * Otherwise, the input buffer begins with the control frame payload.
	 */
	FSTRM_CONTROL_FLAG_WITH_HEADER		= (1 << 0),
} fstrm_control_flag;

/**
 * Convert an `fstrm_control_type` enum value to a string representation.
 * Unknown values are represented as `"FSTRM_CONTROL_UNKNOWN"`.
 *
 * \param type The `fstrm_control_type` enum value.
 * \return The string representation of the enum value. (Always non-NULL.)
 */
const char *
fstrm_control_type_to_str(fstrm_control_type type);

/**
 * Convert an `fstrm_control_field` enum value to a string representation.
 * Unknown values are represented as `"FSTRM_CONTROL_FIELD_UNKNOWN"`.
 *
 * \param f_type The `fstrm_control_field` enum value.
 * \return The string representation of the enum value. (Always non-NULL.)
 */
const char *
fstrm_control_field_type_to_str(fstrm_control_field f_type);

/**
 * Initialize an `fstrm_control` object. This object represents Frame Streams
 * control frames and is used for encoding and decoding control frames.
 *
 * \return
 *	An `fstrm_control` object.
 */
struct fstrm_control *
fstrm_control_init(void);

/**
 * Destroy an `fstrm_control` object.
 *
 * \param[in] c
 *	Pointer to an `fstrm_control` object.
 */
void
fstrm_control_destroy(struct fstrm_control **c);

/**
 * Reinitialize an `fstrm_control` object. This resets the internal state to
 * default values.
 *
 * \param c
 *	`fstrm_control` object.
 */
void
fstrm_control_reset(struct fstrm_control *c);

/**
 * Retrieve the type of the control frame.
 *
 * \param c
 *	`fstrm_control` object.
 * \param[out] type
 *	Type of the control frame.
 *
 * \retval #fstrm_res_success
 * \retval #fstrm_res_failure
 */
fstrm_res
fstrm_control_get_type(
	const struct fstrm_control *c,
	fstrm_control_type *type);

/**
 * Set the type of the control frame.
 *
 * \param c
 *	`fstrm_control` object.
 * \param[in] type
 *	Type of the control frame.
 *
 * \retval #fstrm_res_success
 * \retval #fstrm_res_failure
 */
fstrm_res
fstrm_control_set_type(
	struct fstrm_control *c,
	fstrm_control_type type);

/**
 * Retrieve the number of "Content Type" fields present in the control frame.
 *
 * \param c
 *	`fstrm_control` object.
 * \param[out] n_content_type
 *	The number of "Content Type" fields.
 *
 * \retval #fstrm_res_success
 * \retval #fstrm_res_failure
 */
fstrm_res
fstrm_control_get_num_field_content_type(
	const struct fstrm_control *c,
	size_t *n_content_type);

/**
 * Retrieve a "Content Type" field from the control frame. This function
 * returns a reference which must not be modified. Control frames may contain
 * zero, one, or more "Content Type" fields.
 *
 * \see fstrm_control_get_num_field_content_type()
 *
 * \param c
 *	`fstrm_control` object.
 * \param[in] idx
 *	The index of the "Content Type" field to retrieve.
 * \param[out] content_type
 *	Pointer to where the reference to the "Content Type" string will be
 *	stored. Note that this string is not NUL-terminated and may contain
 *	embedded NULs.
 * \param[out] len_content_type
 *	The number of bytes in `content_type`.
 *
 * \retval #fstrm_res_success
 *	The control frame has a "Content Type" field.
 * \retval #fstrm_res_failure
 *	The control frame does not have a "Content Type" field.
 */
fstrm_res
fstrm_control_get_field_content_type(
	const struct fstrm_control *c,
	const size_t idx,
	const uint8_t **content_type,
	size_t *len_content_type);

/**
 * Add a "Content Type" field to the control frame. This function makes a copy
 * of the provided string. This function may be called multiple times, in which
 * case multiple "Content Type" fields will be added to the control frame.
 *
 * The "Content Type" fields are removed on a call to fstrm_control_reset().
 *
 * \param c
 *	`fstrm_control` object.
 * \param[in] content_type
 *	The "Content Type" string to copy. Note that this string is not
 *	NUL-terminated and may contain embedded NULs.
 * \param[in] len_content_type
 *	The number of bytes in `content_type`.
 *
 * \retval #fstrm_res_success
 *	The "Content Type" field was successfully added.
 * \retval #fstrm_res_failure
 *	The "Content Type" string is too long.
 */
fstrm_res
fstrm_control_add_field_content_type(
	struct fstrm_control *c,
	const uint8_t *content_type,
	size_t len_content_type);

/**
 * Check if the control frame matches a particular content type value. That is,
 * the content type given in the `match` and `len_match` parameters is checked
 * for compatibility with the content types (if any) specified in the control
 * frame.
 *
 * \param c
 *	`fstrm_control` object.
 * \param match
 *	The "Content Type" string to match. Note that this string is not
 *	NUL-terminated and may contain embedded NULs. May be NULL, in which case
 *	the control frame must not have any content type fields in order to
 *	match.
 * \param len_match
 *	The number of bytes in `match`.
 *
 * \retval #fstrm_res_success
 *	A match was found.
 * \retval #fstrm_res_failure
 *	A match was not found.
 */
fstrm_res
fstrm_control_match_field_content_type(
	const struct fstrm_control *c,
	const uint8_t *match,
	const size_t len_match);

/**
 * Decode a control frame from a buffer. The buffer starts with either the
 * escape sequence or the control frame payload depending on whether the
 * `FSTRM_CONTROL_FLAG_WITH_HEADER` flag is set or not. In either case, the
 * 'len_control_frame' parameter must be exact. Underflow or overflow is not
 * permitted.
 *
 * The following code example shows a function that decodes a control frame
 * payload:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
static fstrm_res
decode_control_frame(const void *control_frame, size_t len_control_frame)
{
        fstrm_res res;
        fstrm_control_type c_type;
        struct fstrm_control *c;
        uint32_t flags = 0;

        c = fstrm_control_init();

        res = fstrm_control_decode(c, control_frame, len_control_frame, flags);
        if (res != fstrm_res_success) {
                puts("fstrm_control_decode() failed.");
                fstrm_control_destroy(&c);
                return res;
        }

        res = fstrm_control_get_type(c, &c_type);
        if (res != fstrm_res_success) {
                puts("fstrm_control_get_type() failed.");
                fstrm_control_destroy(&c);
                return res;
        }
        printf("The control frame is of type %s (%u).\n",
               fstrm_control_type_to_str(c_type), c_type);

	size_t n_content_type;
	res = fstrm_control_get_num_field_content_type(c, &n_content_type);
	if (res != fstrm_res_success) {
		puts("fstrm_control_get_num_field_content_type() failed.");
		fstrm_control_destroy(&c);
		return res;
	}

        const uint8_t *content_type;
        size_t len_content_type;
	for (size_t idx = 0; idx < n_content_type; idx++) {
		res = fstrm_control_get_field_content_type(c, idx,
			&content_type, &len_content_type);
		if (res == fstrm_res_success) {
			printf("The control frame has a CONTENT_TYPE field of length %zd.\n",
			       len_content_type);
		}
	}

        fstrm_control_destroy(&c);
        return fstrm_res_success;
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 * \param c
 *	`fstrm_control` object. Its state will be overwritten.
 * \param[in] control_frame
 *	Buffer containing the serialized control frame.
 * \param[in] len_control_frame
 *	The number of bytes in `control_frame`. This parameter must specify the
 *	exact number of bytes in the control frame.
 * \param flags
 *	Flags controlling the decoding process. See #fstrm_control_flag.
 *
 * \retval #fstrm_res_success
 * \retval #fstrm_res_failure
 */
fstrm_res
fstrm_control_decode(
	struct fstrm_control *c,
	const void *control_frame,
	size_t len_control_frame,
	const uint32_t flags);

/**
 * Calculate the number of bytes needed to serialize the control frame.
 *
 * \param c
 *	`fstrm_control` object.
 * \param[out] len_control_frame
 *	The number of bytes needed to encode `c`.
 * \param flags
 *	Flags controlling the encoding process. See #fstrm_control_flag.
 *
 * \retval #fstrm_res_success
 * \retval #fstrm_res_failure
 */
fstrm_res
fstrm_control_encoded_size(
	const struct fstrm_control *c,
	size_t *len_control_frame,
	const uint32_t flags);

/**
 * Encode a control frame into a buffer. Since a Frame Streams control frame is
 * a variable length byte sequence of up to #FSTRM_CONTROL_FRAME_LENGTH_MAX
 * bytes, this function can be used in two different ways. The first way is to
 * call fstrm_control_encoded_size() to obtain the exact number of bytes needed
 * to encode the frame, and then pass a buffer of this exact size to
 * fstrm_control_encode(). The following example shows this usage:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	fstrm_res res;
	struct fstrm_control *c;
	uint8_t *control_frame;
	size_t len_control_frame;
	uint32_t flags = 0;

	c = fstrm_control_init();
	res = fstrm_control_set_type(c, FSTRM_CONTROL_START);
	if (res != fstrm_res_success) {
		// Error handling goes here.
	}

	// Calculate the number of bytes needed.
	res = fstrm_control_encoded_size(c, &len_control_frame, flags);
	if (res != fstrm_res_success) {
		// Error handling goes here.
	}

	// 'len_control_frame' now specifies the number of bytes required for
	// the control frame. Allocate the needed space.
	control_frame = malloc(len_control_frame);
	if (!control_frame) {
		// Error handling goes here.
	}

	// Serialize the control frame into the allocated buffer.
	res = fstrm_control_encode(c, control_frame, &len_control_frame, 0);
	if (res != fstrm_res_success) {
		// Error handling goes here.
	}

	// Do something with 'control_frame' and 'len_control_frame'.

	// Clean up.
	free(control_frame);
	fstrm_control_destroy(&c);
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 * The second way to use fstrm_control_encode() is to allocate a statically
 * sized buffer of #FSTRM_CONTROL_FRAME_LENGTH_MAX bytes. The exact number of
 * bytes serialized by the encoder will be returned in the `len_control_frame`
 * parameter. The following example shows this usage:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	fstrm_res res;
	struct fstrm_control *c;
	uint8_t control_frame[FSTRM_CONTROL_FRAME_LENGTH_MAX];
	size_t len_control_frame = sizeof(control_frame);

	c = fstrm_control_init();
	res = fstrm_control_set_type(c, FSTRM_CONTROL_START);
	if (res != fstrm_res_success) {
		// Error handling.
	}

	// Serialize the control frame.
	res = fstrm_control_encode(c, control_frame, &len_control_frame, 0);
	if (res != fstrm_res_success) {
		// Error handling goes here.
	}

	// Do something with 'control_frame' and 'len_control_frame'.

	// Clean up.
	fstrm_control_destroy(&c);
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 * \param c
 *	`fstrm_control` object.
 * \param[out] control_frame
 *	The buffer in which to serialize the control frame.
 * \param[in,out] len_control_frame
 *	The size in bytes of `control_frame`. On a successful return, contains
 *	the number of bytes actually written into `control_frame`.
 * \param flags
 *	Flags controlling the encoding process. See #fstrm_control_flag.
 *
 * \retval #fstrm_res_success
 * \retval #fstrm_res_failure
 */
fstrm_res
fstrm_control_encode(
	const struct fstrm_control *c,
	void *control_frame,
	size_t *len_control_frame,
	const uint32_t flags);

/**@}*/

#endif /* FSTRM_CONTROL_H */
tcp_writer.h000064400000006370150422026360007105 0ustar00/*
 * Copyright (c) 2014, 2018 by Farsight Security, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */

#ifndef FSTRM_TCP_WRITER_H
#define FSTRM_TCP_WRITER_H

/**
 * \defgroup fstrm_tcp_writer fstrm_tcp_writer
 *
 * `fstrm_tcp_writer` is an interface for opening an \ref fstrm_writer object
 * that is backed by I/O on a TCP socket.
 *
 * @{
 */

/**
 * Initialize an `fstrm_tcp_writer_options` object, which is needed to
 * configure the socket address and socket port to be opened by the writer.
 *
 * \return
 *	`fstrm_tcp_writer_options` object.
 */
struct fstrm_tcp_writer_options *
fstrm_tcp_writer_options_init(void);

/**
 * Destroy an `fstrm_tcp_writer_options` object.
 *
 * \param twopt
 *	Pointer to `fstrm_tcp_writer_options` object.
 */
void
fstrm_tcp_writer_options_destroy(
	struct fstrm_tcp_writer_options **twopt);

/**
 * Set the `socket_address` option. This is the IPv4 or IPv6 address in
 * presentation format to be connected by the TCP socket.
 *
 * \param twopt
 *	`fstrm_tcp_writer_options` object.
 * \param socket_address
 *	The socket address.
 */
void
fstrm_tcp_writer_options_set_socket_address(
	struct fstrm_tcp_writer_options *twopt,
	const char *socket_address);

/**
 * Set the `socket_port` option. This is the TCP port number to be connected by
 * the TCP socket.
 *
 * \param twopt
 *	`fstrm_tcp_writer_options` object.
 * \param socket_port
 *	The TCP socket port number provided as a character string.
 *	(When converted, the maximum allowed unsigned integer is 65535.)
 */
void
fstrm_tcp_writer_options_set_socket_port(
	struct fstrm_tcp_writer_options *twopt,
	const char *socket_port);

/**
 * Initialize the `fstrm_writer` object. Note that the TCP socket will not
 * actually be opened until a subsequent call to fstrm_writer_open().
 *
 * \param twopt
 *	`fstrm_tcp_writer_options` object. Must be non-NULL, and have the
 *	`socket_address` and `socket_port` options set.
 * \param wopt
 *	`fstrm_writer_options` object. May be NULL, in which chase default
 *	values will be used.
 *
 * \return
 *	`fstrm_writer` object.
 * \retval
 *	NULL on failure.
 */
struct fstrm_writer *
fstrm_tcp_writer_init(
	const struct fstrm_tcp_writer_options *twopt,
	const struct fstrm_writer_options *wopt);

/**@}*/

#endif /* FSTRM_TCP_WRITER_H */
rdwr.h000064400000022513150422026360005676 0ustar00/*
 * Copyright (c) 2014 by Farsight Security, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */

#ifndef FSTRM_RDWR_H
#define FSTRM_RDWR_H

/**
 * \defgroup fstrm_rdwr fstrm_rdwr
 *
 * `fstrm_rdwr` is an interface for abstracting the process of reading and
 * writing data to byte streams. It allows extending the `fstrm` library to
 * support reading and writing Frame Streams data to new kinds of byte stream
 * transports. (It also allows building mock interfaces for testing the correct
 * functioning of the library.)
 *
 * `fstrm_rdwr` is a low-level interface that is used in conjunction with the
 * higher level \ref fstrm_reader and \ref fstrm_writer interfaces. The
 * following methods need to be defined for `fstrm_rdwr` implementations:
 *
 * Method name  | Method type                   | Method description
 * ------------ | ----------------------------- | ------------------
 * `destroy`    | #fstrm_rdwr_destroy_func      | Destroys the instance.
 * `open`       | #fstrm_rdwr_open_func         | Opens the stream.
 * `close`      | #fstrm_rdwr_close_func        | Closes the stream.
 * `read`       | #fstrm_rdwr_read_func         | Reads bytes from the stream.
 * `write`      | #fstrm_rdwr_write_func        | Writes bytes to the stream.
 *
 * The `destroy` method is optional. It cleans up any remaining resources
 * associated with the instance.
 *
 * The `open` method is required. It should perform the actual opening of the
 * byte stream and prepare it to read or write data.
 *
 * The `close` method is required. It should perform the actual closing of the
 * byte stream.
 *
 * If the `fstrm_rdwr` object is to be used in an `fstrm_reader` object, it must
 * have a `read` method. If the `fstrm_rdwr` object embedded in an
 * `fstrm_reader` object also has a `write` method, the stream will be
 * considered bi-directional (that is, it supports both reading and writing) and
 * handshaking will be performed. If a `read` method is supplied but a `write`
 * method is not, the reader's stream will instead be considered
 * uni-directional. See \ref fstrm_reader for details.
 *
 * If the `fstrm_rdwr` object is to be used in an `fstrm_writer` object, it must
 * have a `write` method. If the `fstrm_rdwr` object embedded in an
 * `fstrm_writer` object also has a `read` method, the stream will be considered
 * bi-directional and shaking will be performed. If a `write` method is supplied
 * but a `read` method is not, the writer's stream will instead be considered
 * uni-directional. See \ref fstrm_writer for details.
 *
 * An `fstrm_rdwr` instance is created with a call to `fstrm_rdwr_init()`,
 * optionally passing a pointer to some state object associated with the
 * instance. This pointer will be passed as the first argument to each of the
 * methods described above. Then, the various `fstrm_rdwr_set_*()` functions
 * should be used to configure the functions to be used to invoke the methods
 * required for the `fstrm_rdwr` object.
 *
 * @{
 */

/**
 * `destroy` method function type. This method is invoked to deallocate any
 * per-stream resources used by an `fstrm_rdwr` implementation.
 *
 * \see fstrm_rdwr_set_destroy()
 *
 * \param obj
 *      The `obj` value passed to `fstrm_rdwr_init()`.
 *
 * \retval #fstrm_res_success
 * \retval #fstrm_res_failure
 */
typedef fstrm_res
(*fstrm_rdwr_destroy_func)(void *obj);

/**
 * `open` method function type. This method is invoked to open the stream and
 * prepare it for reading or writing. For example, if an `fstrm_rdwr`
 * implementation is backed by file I/O, this method might be responsible for
 * opening a file descriptor.
 *
 * \see fstrm_rdwr_set_open()
 *
 * \param obj
 *      The `obj` value passed to `fstrm_rdwr_init()`.
 *
 * \retval #fstrm_res_success
 * \retval #fstrm_res_failure
 */
typedef fstrm_res
(*fstrm_rdwr_open_func)(void *obj);

/**
 * `close` method function type. This method is invoked to close the stream. For
 * example, if an `fstrm_rdwr` implementation is backed by file I/O, this method
 * might be responsible for closing a file descriptor.
 *
 * \see fstrm_rdwr_set_close()
 *
 * \param obj
 *      The `obj` value passed to `fstrm_rdwr_init()`.
 *
 * \retval #fstrm_res_success
 * \retval #fstrm_res_failure
 */
typedef fstrm_res
(*fstrm_rdwr_close_func)(void *obj);

/**
 * `read` method function type. This method is used to read data from a stream.
 * It must satisfy the full amount of data requested, unless the stream has
 * ended.
 *
 * \see fstrm_rdwr_set_read()
 *
 * \param obj
 *      The `obj` value passed to `fstrm_rdwr_init()`.
 * \param data
 *      The buffer in which to place the data read.
 * \param count
 *      The number of bytes requested.
 *
 * \retval #fstrm_res_success
 *      The data was read successfully.
 * \retval #fstrm_res_failure
 *      An unexpected failure occurred.
 * \retval #fstrm_res_stop
 *      The end of the stream has occurred.
 */
typedef fstrm_res
(*fstrm_rdwr_read_func)(void *obj, void *data, size_t count);

/**
 * `write` method function type. This method is used to write data to a stream.
 * It must perform the full write of all data, unless an error has occurred.
 *
 * \see fstrm_rdwr_set_write()
 *
 * \param obj
 *      The `obj` value passed to `fstrm_rdwr_init()`.
 * \param iov
 *      Array of `struct iovec` objects.
 * \param iovcnt
 *      Number of `struct iovec` objects in `iov`.
 *
 * \return #fstrm_res_success
 * \return #fstrm_res_failure
 */
typedef fstrm_res
(*fstrm_rdwr_write_func)(void *obj, const struct iovec *iov, int iovcnt);

/**
 * Initialize a new `fstrm_rdwr` object.
 *
 * \param obj
 *      Per-object state.
 *
 * \return
 *      `fstrm_rdwr` object.
 * \retval
 *      NULL on failure.
 */
struct fstrm_rdwr *
fstrm_rdwr_init(void *obj);

/**
 * Destroy an `fstrm_rdwr` object. This invokes the underlying `destroy` method
 * as well.
 *
 * \param rdwr
 *      Pointer to an `fstrm_rdwr` object.
 *
 * \return #fstrm_res_success
 * \return #fstrm_res_failure
 */
fstrm_res
fstrm_rdwr_destroy(struct fstrm_rdwr **rdwr);

/**
 * Invoke the `open` method on an `fstrm_rdwr` object.
 *
 * \param rdwr
 *      The `fstrm_rdwr` object.
 *
 * \return #fstrm_res_success
 * \return #fstrm_res_failure
 */
fstrm_res
fstrm_rdwr_open(struct fstrm_rdwr *rdwr);

/**
 * Invoke the `close` method on an `fstrm_rdwr` object.
 *
 * \param rdwr
 *      The `fstrm_rdwr` object.
 *
 * \return #fstrm_res_success
 * \return #fstrm_res_failure
 */
fstrm_res
fstrm_rdwr_close(struct fstrm_rdwr *rdwr);

/**
 * Invoke the `read` method on an `fstrm_rdwr` object.
 *
 * \param rdwr
 *      The `fstrm_rdwr` object.
 * \param data
 *      The buffer in which to place the data read.
 * \param count
 *      The number of bytes to read.
 *
 * \return #fstrm_res_success
 * \return #fstrm_res_failure
 * \return #fstrm_res_stop
 */
fstrm_res
fstrm_rdwr_read(struct fstrm_rdwr *rdwr, void *data, size_t count);

/**
 * Invoke the `write` method on an `fstrm_rdwr` object.
 *
 * \param rdwr
 *      The `fstrm_rdwr` object.
 * \param iov
 *      Array of `struct iovec` objects.
 * \param iovcnt
 *      Number of `struct iovec` objects in `iov`.
 *
 * \return #fstrm_res_success
 * \return #fstrm_res_failure
 */
fstrm_res
fstrm_rdwr_write(struct fstrm_rdwr *rdwr, const struct iovec *iov, int iovcnt);

/**
 * Set the `destroy` method for an `fstrm_rdwr` object.
 *
 * \param rdwr
 *      The `fstrm_rdwr` object.
 * \param fn
 *      Function to use.
 */
void
fstrm_rdwr_set_destroy(
	struct fstrm_rdwr *rdwr,
	fstrm_rdwr_destroy_func fn);

/**
 * Set the `open` method for an `fstrm_rdwr` object.
 *
 * \param rdwr
 *      The `fstrm_rdwr` object.
 * \param fn
 *      Function to use.
 */
void
fstrm_rdwr_set_open(
	struct fstrm_rdwr *rdwr,
	fstrm_rdwr_open_func fn);

/**
 * Set the `close` method for an `fstrm_rdwr` object.
 *
 * \param rdwr
 *      The `fstrm_rdwr` object.
 * \param fn
 *      Function to use.
 */
void
fstrm_rdwr_set_close(
	struct fstrm_rdwr *rdwr,
	fstrm_rdwr_close_func fn);

/**
 * Set the `read` method for an `fstrm_rdwr` object.
 *
 * \param rdwr
 *      The `fstrm_rdwr` object.
 * \param fn
 *      Function to use.
 */
void
fstrm_rdwr_set_read(
	struct fstrm_rdwr *rdwr,
	fstrm_rdwr_read_func fn);

/**
 * Set the `write` method for an `fstrm_rdwr` object.
 *
 * \param rdwr
 *      The `fstrm_rdwr` object.
 * \param fn
 *      Function to use.
 */
void
fstrm_rdwr_set_write(
	struct fstrm_rdwr *rdwr,
	fstrm_rdwr_write_func fn);

/**@}*/

#endif /* FSTRM_RDWR_H */
file.h000064400000006216150422026360005641 0ustar00/*
 * Copyright (c) 2014 by Farsight Security, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */

#ifndef FSTRM_FILE_H
#define FSTRM_FILE_H

/**
 * \defgroup fstrm_file fstrm_file
 *
 * `fstrm_file` contains interfaces for opening \ref fstrm_reader or
 * \ref fstrm_writer objects that are backed by file I/O.
 *
 * @{
 */

/**
 * Initialize an `fstrm_file_options` object, which is needed to configure the
 * file path to be opened by fstrm_file_reader_init() or
 * fstrm_file_writer_init().
 *
 * \return
 *	`fstrm_file_options` object.
 */
struct fstrm_file_options *
fstrm_file_options_init(void);

/**
 * Destroy an `fstrm_file_options` object.
 *
 * \param fopt
 *	Pointer to `fstrm_file_options` object.
 */
void
fstrm_file_options_destroy(struct fstrm_file_options **fopt);

/**
 * Set the `file_path` option. This is a filesystem path to a regular file to be
 * opened for reading or writing.
 *
 * \param fopt
 *	`fstrm_file_options` object.
 * \param file_path
 *	The filesystem path for a regular file.
 */
void
fstrm_file_options_set_file_path(struct fstrm_file_options *fopt,
				 const char *file_path);

/**
 * Open a file containing Frame Streams data for reading.
 *
 * \param fopt
 *	`fstrm_file_options` object. Must be non-NULL, and have the `file_path`
 *	option set.
 * \param ropt
 *	`fstrm_reader_options` object. May be NULL, in which case default values
 *	will be used.
 *
 * \return
 *	`fstrm_reader` object.
 * \retval
 *	NULL on failure.
 */
struct fstrm_reader *
fstrm_file_reader_init(const struct fstrm_file_options *fopt,
		       const struct fstrm_reader_options *ropt);

/**
 * Open a file for writing Frame Streams data. The file will be truncated if it
 * already exists.
 *
 * \param fopt
 *	`fstrm_file_options` object. Must be non-NULL, and have the `file_path`
 *	option set.
 * \param wopt
 *	`fstrm_writer_options` object. May be NULL, in which case default values
 *	will be used.
 *
 * \return
 *	`fstrm_writer` object.
 * \retval
 *	NULL on failure.
 */
struct fstrm_writer *
fstrm_file_writer_init(const struct fstrm_file_options *fopt,
		       const struct fstrm_writer_options *wopt);

/**@}*/

#endif /* FSTRM_FILE_H */
iothr.h000064400000036170150422026360006051 0ustar00/*
 * Copyright (c) 2014 by Farsight Security, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */

#ifndef FSTRM_IOTHR_H
#define FSTRM_IOTHR_H

/**
 * \defgroup fstrm_iothr fstrm_iothr
 *
 * The `fstrm_iothr` interface creates a background I/O thread which writes
 * Frame Streams encapsulated data frames into an output stream specified by an
 * \ref fstrm_writer object. It exposes non-blocking input queues that can be
 * used by worker threads to asynchronously write data frames to the output
 * stream. A deferred deallocation callback is invoked after the I/O thread has
 * disposed of a queued data frame.
 *
 * In order to create an `fstrm_iothr` object, the caller must first configure
 * and instantiate an `fstrm_writer` object and pass this instance to the
 * fstrm_iothr_init() function. The `fstrm_iothr` object then takes ownership of
 * the `fstrm_writer` object. It is responsible for serializing writes and will
 * take care of destroying the captive `fstrm_writer` object at the same time
 * the `fstrm_iothr` object is destroyed. The caller should not perform any
 * operations on the captive `fstrm_writer` object after it has been passed to
 * `fstrm_iothr_init()`.
 *
 * Parameters used to configure the I/O thread are passed through an
 * `fstrm_iothr_options` object. These options have to be specified in advance
 * and are mostly performance knobs which have reasonable defaults.
 *
 * Once the `fstrm_iothr` object has been created, handles to the input queues
 * used to submit data frames can be obtained by calling
 * `fstrm_iothr_get_input_queue()`. This function can be called up to
 * **num_input_queues** times, and can be safely called concurrently. For
 * instance, in an application with a fixed number of worker threads, an input
 * queue can be dedicated to each worker thread by setting the
 * **num_input_queues** option to the number of worker threads, and then calling
 * `fstrm_iothr_get_input_queue()` from each worker thread's startup function to
 * obtain a per-thread input queue.
 *
 * @{
 */

/**
 * Initialize an `fstrm_iothr_options` object. This is needed to pass
 * configuration parameters to fstrm_iothr_init().
 *
 * \return
 *	`fstrm_iothr_options` object.
 */
struct fstrm_iothr_options *
fstrm_iothr_options_init(void);

/**
 * Destroy an `fstrm_iothr_options` object.
 *
 * \param opt
 *	Pointer to `fstrm_iothr_options` object.
 */
void
fstrm_iothr_options_destroy(struct fstrm_iothr_options **opt);

/**
 * Set the `buffer_hint` parameter. This is the threshold number of bytes to
 * accumulate in the output buffer before forcing a buffer flush.
 *
 * \param opt
 *	`fstrm_iothr_options` object.
 * \param buffer_hint
 *	New `buffer_hint` value.
 *
 * \retval #fstrm_res_success
 * \retval #fstrm_res_failure
 */
fstrm_res
fstrm_iothr_options_set_buffer_hint(
	struct fstrm_iothr_options *opt,
	unsigned buffer_hint);

/** Minimum `buffer_hint` value. */
#define FSTRM_IOTHR_BUFFER_HINT_MIN			1024

/** Default `buffer_hint` value. */
#define FSTRM_IOTHR_BUFFER_HINT_DEFAULT			8192

/** Maximum `buffer_hint` value. */
#define FSTRM_IOTHR_BUFFER_HINT_MAX			65536

/**
 * Set the `flush_timeout` parameter. This is the number of seconds to allow
 * unflushed data to remain in the output buffer.
 *
 * \param opt
 *	`fstrm_iothr_options` object.
 * \param flush_timeout
 *	New `flush_timeout` value.
 *
 * \retval #fstrm_res_success
 * \retval #fstrm_res_failure
 */
fstrm_res
fstrm_iothr_options_set_flush_timeout(
	struct fstrm_iothr_options *opt,
	unsigned flush_timeout);

/** Minimum `flush_timeout` value. */
#define FSTRM_IOTHR_FLUSH_TIMEOUT_MIN			1

/** Default `flush_timeout` value. */
#define FSTRM_IOTHR_FLUSH_TIMEOUT_DEFAULT		1

/** Maximum `flush_timeout` value. */
#define FSTRM_IOTHR_FLUSH_TIMEOUT_MAX			600

/**
 * Set the `input_queue_size` parameter. This is the number of queue entries to
 * allocate per each input queue. This option controls the number of outstanding
 * data frames per input queue that can be outstanding for deferred processing
 * by the `fstrm_iothr` object and thus affects performance and memory usage.
 *
 * This parameter must be a power-of-2.
 *
 * \param opt
 *	`fstrm_iothr_options` object.
 * \param input_queue_size
 *	New `input_queue_size` value.
 *
 * \retval #fstrm_res_success
 * \retval #fstrm_res_failure
 */
fstrm_res
fstrm_iothr_options_set_input_queue_size(
	struct fstrm_iothr_options *opt,
	unsigned input_queue_size);

/** Minimum `input_queue_size` value. */
#define FSTRM_IOTHR_INPUT_QUEUE_SIZE_MIN		2

/** Default `input_queue_size` value. */
#define FSTRM_IOTHR_INPUT_QUEUE_SIZE_DEFAULT		512

/** Maximum `input_queue_size` value. */
#define FSTRM_IOTHR_INPUT_QUEUE_SIZE_MAX		16384

/**
 * Set the `num_input_queues` parameter. This is the number of input queues to
 * create and must match the number of times that fstrm_iothr_get_input_queue()
 * is called on the corresponding `fstrm_iothr` object.
 *
 * \param opt
 *	`fstrm_iothr_options` object.
 * \param num_input_queues
 *	New `num_input_queues` value.
 *
 * \retval #fstrm_res_success
 * \retval #fstrm_res_failure
 */
fstrm_res
fstrm_iothr_options_set_num_input_queues(
	struct fstrm_iothr_options *opt,
	unsigned num_input_queues);

/** Minimum `num_input_queues` value. */
#define FSTRM_IOTHR_NUM_INPUT_QUEUES_MIN		1

/** Default `num_input_queues` value. */
#define FSTRM_IOTHR_NUM_INPUT_QUEUES_DEFAULT		1

/**
 * Set the `output_queue_size` parameter. This is the number of queue entries to
 * allocate for the output queue. This option controls the maximum number of
 * data frames that can be accumulated in the output queue before a buffer flush
 * must occur and thus affects performance and memory usage.
 *
 * \param opt
 *	`fstrm_iothr_options` object.
 * \param output_queue_size
 *	New `output_queue_size` value.
 *
 * \retval #fstrm_res_success
 * \retval #fstrm_res_failure
 */
fstrm_res
fstrm_iothr_options_set_output_queue_size(
	struct fstrm_iothr_options *opt,
	unsigned output_queue_size);

/** Minimum `output_queue_size` value. */
#define FSTRM_IOTHR_OUTPUT_QUEUE_SIZE_MIN		2

/** Default `output_queue_size` value. */
#define FSTRM_IOTHR_OUTPUT_QUEUE_SIZE_DEFAULT		64

/** Maximum `output_queue_size` value. */
#define FSTRM_IOTHR_OUTPUT_QUEUE_SIZE_MAX		IOV_MAX

/**
 * Queue models.
 * \see fstrm_iothr_options_set_queue_model()
 */
typedef enum {
	/** Single Producer, Single Consumer. */
	FSTRM_IOTHR_QUEUE_MODEL_SPSC,

	/** Multiple Producer, Single Consumer. */
	FSTRM_IOTHR_QUEUE_MODEL_MPSC,
} fstrm_iothr_queue_model;


/**
 * Set the `queue_model` parameter. This controls what queueing semantics to use
 * for `fstrm_iothr_queue` objects. Single Producer queues
 * (#FSTRM_IOTHR_QUEUE_MODEL_SPSC) may only have a single thread at a time
 * calling fstrm_iothr_submit() on a given `fstrm_iothr_queue` object, while
 * Multiple Producer queues (#FSTRM_IOTHR_QUEUE_MODEL_MPSC) may have multiple
 * threads concurrently calling fstrm_iothr_submit() on a given
 * `fstrm_iothr_queue` object.
 *
 * \param opt
 *	`fstrm_iothr_options` object.
 * \param queue_model
 *	New `queue_model` value.
 *
 * \retval #fstrm_res_success
 * \retval #fstrm_res_failure
 */
fstrm_res
fstrm_iothr_options_set_queue_model(
	struct fstrm_iothr_options *opt,
	fstrm_iothr_queue_model queue_model);

/** Default `queue_model` value. */
#define FSTRM_IOTHR_QUEUE_MODEL_DEFAULT			FSTRM_IOTHR_QUEUE_MODEL_SPSC

/**
 * Set the `queue_notify_threshold` parameter. This controls the number of
 * outstanding queue entries to allow on an input queue before waking the I/O
 * thread, which will cause the outstanding queue entries to begin draining.
 *
 * \param opt
 *	`fstrm_iothr_options` object.
 * \param queue_notify_threshold
 *	New `queue_notify_threshold` value.
 *
 * \retval #fstrm_res_success
 * \retval #fstrm_res_failure
 */
fstrm_res
fstrm_iothr_options_set_queue_notify_threshold(
	struct fstrm_iothr_options *opt,
	unsigned queue_notify_threshold);

/** Minimum `queue_notify_threshold` value. */
#define FSTRM_IOTHR_QUEUE_NOTIFY_THRESHOLD_MIN		1

/** Default `queue_notify_threshold` value. */
#define FSTRM_IOTHR_QUEUE_NOTIFY_THRESHOLD_DEFAULT	32

/**
 * Set the `reopen_interval` parameter. This controls the number of seconds to
 * wait between attempts to reopen a closed `fstrm_writer` output stream.
 *
 * \param opt
 *	`fstrm_iothr_options` object.
 * \param reopen_interval
 *	New `queue_notify_threshold` value.
 *
 * \retval #fstrm_res_success
 * \retval #fstrm_res_failure
 */
fstrm_res
fstrm_iothr_options_set_reopen_interval(
	struct fstrm_iothr_options *opt,
	unsigned reopen_interval);

/** Minimum `reopen_interval` value. */
#define FSTRM_IOTHR_REOPEN_INTERVAL_MIN			1

/** Default `reopen_interval` value. */
#define FSTRM_IOTHR_REOPEN_INTERVAL_DEFAULT		5

/** Maximum `reopen_interval` value. */
#define FSTRM_IOTHR_REOPEN_INTERVAL_MAX			600

/**
 * Initialize an `fstrm_iothr` object. This creates a background I/O thread
 * which asynchronously writes data frames submitted by other threads which call
 * fstrm_iothr_submit().
 *
 * \param opt
 *	`fstrm_iothr_options` object. May be NULL, in which case default values
 *	will be used.
 *
 * \param writer
 *	Pointer to `fstrm_writer` object. Must be non-NULL.
 *
 * \return
 *	`fstrm_iothr` object.
 * \retval
 *	NULL on failure.
 */
struct fstrm_iothr *
fstrm_iothr_init(
	const struct fstrm_iothr_options *opt,
	struct fstrm_writer **writer);

/**
 * Destroy an `fstrm_iothr` object. This signals the background I/O thread to
 * flush or discard any queued data frames and deallocates any resources used
 * internally. This function blocks until the I/O thread has terminated.
 *
 * \param iothr
 *	Pointer to `fstrm_iothr` object.
 */
void
fstrm_iothr_destroy(struct fstrm_iothr **iothr);

/**
 * Obtain an `fstrm_iothr_queue` object for submitting data frames to the
 * `fstrm_iothr` object. `fstrm_iothr_queue` objects are child objects of their
 * parent `fstrm_iothr` object and will be destroyed when fstrm_iothr_destroy()
 * is called on the parent `fstrm_iothr` object.
 *
 * This function is thread-safe and may be called simultaneously from any
 * thread. For example, in a program which employs a fixed number of worker
 * threads to handle requests, fstrm_iothr_get_input_queue() may be called from
 * a thread startup routine without synchronization.
 *
 * `fstrm_iothr` objects allocate a fixed total number of `fstrm_iothr_queue`
 * objects during the call to fstrm_iothr_init(). To adjust this parameter, use
 * fstrm_iothr_options_set_num_input_queues().
 *
 * This function will fail if it is called more than **num_input_queues** times.
 * By default, only one input queue is initialized per `fstrm_iothr` object.
 *
 * For optimum performance in a threaded program, each worker thread submitting
 * data frames should have a dedicated `fstrm_iothr_queue` object. This allows
 * each worker thread to have its own queue which is processed independently by
 * the I/O thread. If the queue model for the `fstrm_iothr` object is set to
 * #FSTRM_IOTHR_QUEUE_MODEL_SPSC, this results in contention-free access to the
 * input queue.
 *
 * \param iothr
 *	`fstrm_iothr` object.
 *
 * \return
 *	`fstrm_iothr_queue` object.
 * \retval
 *	NULL on failure.
 */
struct fstrm_iothr_queue *
fstrm_iothr_get_input_queue(struct fstrm_iothr *iothr);

/**
 * Obtain an `fstrm_iothr_queue` object for submitting data frames to the
 * `fstrm_iothr` object. This function is like fstrm_iothr_get_input_queue()
 * except it indexes into the `fstrm_iothr_queue`'s array of input queues.
 *
 * \param iothr
 *	`fstrm_iothr` object.
 * \param idx
 *	Index of the `fstrm_iothr_queue` object to retrieve. This value is
 *	limited by the **num_input_queues** option.
 *
 * \return
 *	`fstrm_iothr_queue` object.
 * \retval
 *	NULL on failure.
 */
struct fstrm_iothr_queue *
fstrm_iothr_get_input_queue_idx(struct fstrm_iothr *iothr, size_t idx);

/**
 * Submit a data frame to the background I/O thread. If successfully queued and
 * the I/O thread has an active output stream opened, the data frame will be
 * asynchronously written to the output stream.
 *
 * When this function returns #fstrm_res_success, responsibility for
 * deallocating the data frame specified by the `data` parameter passes to the
 * `fstrm` library. The caller **MUST** ensure that the `data` object remains
 * valid after fstrm_iothr_submit() returns. The callback function specified by
 * the `free_func` parameter will be invoked once the data frame is no longer
 * needed by the `fstrm` library. For example, if the data frame is dynamically
 * allocated, the data frame may be deallocated in the callback function.
 *
 * Note that if this function returns #fstrm_res_failure, the responsibility for
 * deallocating the data frame remains with the caller.
 *
 * As a convenience, if `data` is allocated with the system's `malloc()`,
 * `fstrm_free_wrapper` may be provided as the `free_func` parameter with the
 * `free_data` parameter set to `NULL`. This will cause the system's `free()` to
 * be invoked to deallocate `data`.
 *
 * `free_func` may be NULL, in which case no callback function will be invoked
 * to dispose of `buf`. This behavior may be useful if `data` is a global,
 * statically allocated object.
 *
 * \param iothr
 *      `fstrm_iothr` object.
 * \param ioq
 *      `fstrm_iothr_queue` object.
 * \param data
 *      Data frame bytes.
 * \param len
 *      Number of bytes in `data`.
 * \param free_func
 *      Callback function to deallocate the data frame. The `data` and
 *      `free_data` parameters passed to this callback will be the same values
 *      originally supplied in the call to fstrm_iothr_submit().
 * \param free_data
 *      Parameter to pass to `free_func`.
 *
 * \retval #fstrm_res_success
 *      The data frame was successfully queued.
 * \retval #fstrm_res_again
 *      The queue is full.
 * \retval #fstrm_res_failure
 *      Permanent failure.
 */
fstrm_res
fstrm_iothr_submit(
	struct fstrm_iothr *iothr, struct fstrm_iothr_queue *ioq,
	void *data, size_t len,
	void (*free_func)(void *buf, void *free_data), void *free_data);

/**
 * Wrapper function for the system's `free()`, suitable for use as the
 * `free_func` callback for fstrm_iothr_submit().
 *
 * \param data
 *	Object to call `free()` on.
 * \param free_data
 *	Unused.
 */
void
fstrm_free_wrapper(void *data, void *free_data);

/**@}*/

#endif /* FSTRM_IOTHR_H */
writer.h000064400000020426150422026360006235 0ustar00/*
 * Copyright (c) 2014, 2018 by Farsight Security, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */

#ifndef FSTRM_WRITER_H
#define FSTRM_WRITER_H

/**
 * \defgroup fstrm_writer fstrm_writer
 *
 * `fstrm_writer` is an interface for writing Frame Streams data into a byte
 * stream. The underlying byte stream I/O operations are abstracted by the
 * \ref fstrm_rdwr interface. Thus, the `fstrm_writer` interface can be used to
 * write Frame Streams data to any type of output whose read/write operations
 * are wrapped by an `fstrm_rdwr` object.
 *
 * Some basic `fstrm_writer` implementations are already provided in the `fstrm`
 * library. See fstrm_file_writer_init() for an implementation that writes to
 * a regular file, fstrm_tcp_writer_init() for an implementation that writes to
 * a TCP socket, and fstrm_unix_writer_init() for an implementation that writes
 * to a Unix socket.
 *
 * @{
 */

/**
 * Initialize an `fstrm_writer_options` object.
 *
 * \return
 *	`fstrm_writer_options` object.
 */
struct fstrm_writer_options *
fstrm_writer_options_init(void);

/**
 * Destroy an `fstrm_writer_options` object.
 *
 * \param wopt
 *	Pointer to `fstrm_writer_options` object.
 */
void
fstrm_writer_options_destroy(
	struct fstrm_writer_options **wopt);

/**
 * Add a "Content Type" value to the set of content types that can be negotiated
 * by the writer. This function makes a copy of the provided string. This
 * function may be called multiple times, in which case multiple "Content Type"
 * values will be accepted by the reader.
 *
 * For uni-directional streams like regular files, the negotiated content type
 * will simply be the first content type provided to this function. For
 * bi-directional streams like sockets, a handshake occurs and the remote end
 * determines which content type should be sent. In the latter case, after the
 * writer has been successfully opened with a call to fstrm_writer_open(), the
 * fstrm_writer_get_control() function should be called with `type` set to
 * `FSTRM_CONTROL_ACCEPT` and the control frame queried in order to determine
 * the negotiated content type.
 *
 * \param wopt
 *	`fstrm_writer_options` object.
 * \param content_type
 *	The "Content Type" string to copy. Note that this string is not
 *	NUL-terminated and may contain embedded NULs.
 * \param len_content_type
 *	The number of bytes in `content_type`.
 *
 * \retval #fstrm_res_success
 *	The "Content Type" field was successfully added.
 * \retval #fstrm_res_failure
 *	The "Content Type" string is too long.
 */
fstrm_res
fstrm_writer_options_add_content_type(
	struct fstrm_writer_options *wopt,
	const void *content_type,
	size_t len_content_type);

/**
 * Initialize a new `fstrm_writer` object based on an underlying `fstrm_rdwr`
 * object and an `fstrm_writer_options` object.
 *
 * The underlying `fstrm_rdwr` object MUST have a `write` method. It MAY
 * optionally have a `read` method, in which case the stream will be treated as
 * a bi-directional, handshaked stream. Otherwise, if there is no `read` method
 * the stream will be treated as a uni-directional stream.
 *
 * This function is useful for implementing functions that return new types of
 * `fstrm_writer` objects, such as fstrm_file_writer_init() and
 * fstrm_unix_writer_init().
 *
 * After a successful call to this function, the ownership of the `fstrm_rdwr`
 * object passes from the caller to the `fstrm_writer` object. The caller
 * should perform no further calls on the `fstrm_rdwr` object. The `fstrm_rdwr`
 * object will be cleaned up on a call to fstrm_writer_destroy().
 *
 * \param wopt
 *      `fstrm_writer_options` object. May be NULL, in which case default values
 *      will be used.
 *
 * \param rdwr
 *      Pointer to `fstrm_rdwr` object. Must be non-NULL. The `fstrm_rdwr`
 *      object must have a `write` method, and may optionally have a `read`
 *      method.
 *
 * \return
 *      `fstrm_writer` object.
 * \retval
 *      NULL on failure.
 */
struct fstrm_writer *
fstrm_writer_init(
	const struct fstrm_writer_options *wopt,
	struct fstrm_rdwr **rdwr);

/**
 * Destroy an `fstrm_writer` object. This implicitly calls fstrm_writer_close()
 * if necessary.
 *
 * \param w
 *	Pointer to `fstrm_writer` object.
 *
 * \retval #fstrm_res_success
 * \retval #fstrm_res_failure
 */
fstrm_res
fstrm_writer_destroy(struct fstrm_writer **w);

/**
 * Open an `fstrm_writer` object and prepare it to write data. For
 * bi-directional writer implementations, this performs content type
 * negotiation.
 *
 * This function may fail if there was an underlying problem opening the output
 * stream.
 *
 * \param w
 *	`fstrm_writer` object.
 *
 * \retval #fstrm_res_success
 * \retval #fstrm_res_failure
 */
fstrm_res
fstrm_writer_open(struct fstrm_writer *w);

/**
 * Close an `fstrm_writer` object. Open it has been closed, no data frames may
 * subsequently be written.
 *
 * Calling this function is optional; it may be implicitly invoked by a call to
 * fstrm_writer_destroy().
 *
 * \param w
 *	`fstrm_writer` object.
 *
 * \retval #fstrm_res_success
 * \retval #fstrm_res_failure
 */
fstrm_res
fstrm_writer_close(struct fstrm_writer *w);

/**
 * Write a data frame to an `fstrm_writer` object.
 *
 * This function implicitly calls fstrm_writer_open() if necessary.
 *
 * \param w
 *	`fstrm_writer` object.
 * \param[in] data
 *	Buffer containing the data frame payload.
 * \param[in] len_data
 *	The number of bytes in `data`.
 *
 * \retval #fstrm_res_success
 *	The data frame was successfully written.
 * \retval #fstrm_res_failure
 */
fstrm_res
fstrm_writer_write(
	struct fstrm_writer *w,
	const void *data,
	size_t len_data);

/**
 * Write multiple data frames to an `fstrm_writer` object.
 *
 * This function implicitly calls fstrm_writer_open() if necessary.
 * 
 * Data frames are passed similarly to the `writev()` system call, with an array
 * of `struct iovec` objects describing the data frame payloads and their
 * lengths. The complete set of data frames will be written to the output
 * stream after a successful call.
 *
 * \param w
 *	`fstrm_writer` object.
 * \param iov
 *	Array of `struct iovec` objects.
 * \param iovcnt
 *	Number of `struct iovec` objects in `iov`.
 *
 * \retval #fstrm_res_success
 *	The data frames were successfully written.
 * \retval #fstrm_res_failure
 */
fstrm_res
fstrm_writer_writev(
	struct fstrm_writer *w,
	const struct iovec *iov,
	int iovcnt);

/**
 * Obtain a pointer to an `fstrm_control` object used during processing. Objects
 * returned by this function are owned by the `fstrm_reader` object and must not
 * be modified by the caller. After a call to fstrm_reader_destroy() these
 * pointers will no longer be valid.
 *
 * For example, with bi-directional streams this function can be used to obtain
 * a pointer to the ACCEPT control frame, which can be queried to see which
 * "Content Type" was negotiated during the opening of the writer.
 *
 * This function implicitly calls fstrm_writer_open() if necessary.
 *
 * \param w
 *      `fstrm_writer` object.
 * \param type
 *      Which control frame to return.
 * \param[out] control
 *      The `fstrm_control` object.
 *
 * \retval #fstrm_res_success
 *      If an `fstrm_control` object was returned.
 * \retval #fstrm_res_failure
 */
fstrm_res
fstrm_writer_get_control(
	struct fstrm_writer *w,
	fstrm_control_type type,
	struct fstrm_control **control);

/**@}*/

#endif /* FSTRM_WRITER_H */