nghttp2/lib/nghttp2_frame.h

/*
 * nghttp2 - HTTP/2 C Library
 *
 * Copyright (c) 2012 Tatsuhiro Tsujikawa
 *
 * 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 NGHTTP2_FRAME_H
#define NGHTTP2_FRAME_H

#ifdef HAVE_CONFIG_H
#  include <config.h>
#endif /* HAVE_CONFIG_H */

#include <nghttp2/nghttp2.h>
#include "nghttp2_hd.h"
#include "nghttp2_buf.h"

#define NGHTTP2_FRAME_LENGTH_MASK ((1 << 14) - 1)
#define NGHTTP2_STREAM_ID_MASK ((1u << 31) - 1)
#define NGHTTP2_PRI_GROUP_ID_MASK ((1u << 31) - 1)
#define NGHTTP2_PRIORITY_MASK ((1u << 31) - 1)
#define NGHTTP2_WINDOW_SIZE_INCREMENT_MASK ((1u << 31) - 1)
#define NGHTTP2_SETTINGS_ID_MASK ((1 << 24) - 1)

/* The number of bytes of frame header. */
#define NGHTTP2_FRAME_HDLEN 8

/* The maximum frame and payload length. The spec allows maximum
   payload length up to 16383 bytes. Due to efficient buffer
   allocation, we choose smaller buffer. Actual payload limit offsets
   frame header and possible PAD_HIGH and PAD_LOW to ease
   serialization and save memcopying. */
#define NGHTTP2_MAX_FRAMELEN 8192
#define NGHTTP2_MAX_PAYLOADLEN (NGHTTP2_MAX_FRAMELEN - NGHTTP2_FRAME_HDLEN - 2)

/* The maximum length of DATA frame payload. To fit entire DATA frame
   into 4096K buffer, we use subtract header size (8 bytes) + 2 bytes
   padding. See nghttp2_session_pack_data(). */
#define NGHTTP2_DATA_PAYLOAD_LENGTH (4096 - NGHTTP2_FRAME_HDLEN - 2)

/* The number of bytes for each SETTINGS entry */
#define NGHTTP2_FRAME_SETTINGS_ENTRY_LENGTH 5

/* Category of frames. */
typedef enum {
  /* non-DATA frame */
  NGHTTP2_CAT_CTRL,
  /* DATA frame */
  NGHTTP2_CAT_DATA
} nghttp2_frame_category;

/**
 * @struct
 *
 * The DATA frame used in the library privately. It has the following
 * members:
 */
typedef struct {
  nghttp2_frame_hd hd;
  /**
   * The data to be sent for this DATA frame.
   */
  nghttp2_data_provider data_prd;
  /**
   * The number of bytes added as padding. This includes PAD_HIGH and
   * PAD_LOW.
   */
  size_t padlen;
  /**
   * The flag to indicate whether EOF was reached or not. Initially
   * |eof| is 0. It becomes 1 after all data were read. This is used
   * exclusively by nghttp2 library and not in the spec.
   */
  uint8_t eof;
} nghttp2_private_data;

int nghttp2_frame_is_data_frame(uint8_t *head);

void nghttp2_frame_pack_frame_hd(uint8_t *buf, const nghttp2_frame_hd *hd);

void nghttp2_frame_unpack_frame_hd(nghttp2_frame_hd *hd, const uint8_t* buf);

/**
 * Returns the number of priority field depending on the |flags|.  If
 * |flags| has neither NGHTTP2_FLAG_PRIORITY_GROUP nor
 * NGHTTP2_FLAG_PRIORITY_DEPENDENCY set, return 0.
 */
size_t nghttp2_frame_priority_len(uint8_t flags);

/**
 * Packs the |pri_spec| in |buf|.  This function assumes |buf| has
 * enough space for serialization.
 */
void nghttp2_frame_pack_priority_spec(uint8_t *buf,
                                      const nghttp2_priority_spec *pri_spec);

/**
 * Unpacks the priority specification from payload |payload| of length
 * |payloadlen| to |pri_spec|.  The |flags| is used to determine what
 * kind of priority specification is in |payload|.  This function
 * assumes the |payload| contains whole priority specification.
 */
void nghttp2_frame_unpack_priority_spec(nghttp2_priority_spec *pri_spec,
                                        uint8_t flags,
                                        const uint8_t *payload,
                                        size_t payloadlen);

/*
 * Returns the offset from the HEADERS frame payload where the
 * compressed header block starts. The frame payload does not include
 * frame header.
 */
size_t nghttp2_frame_headers_payload_nv_offset(nghttp2_headers *frame);

/*
 * Packs HEADERS frame |frame| in wire format and store it in |bufs|.
 * This function expands |bufs| as necessary to store frame.
 *
 * The caller must make sure that nghttp2_bufs_reset(bufs) is called
 * before calling this function.
 *
 * frame->hd.length is assigned after length is determined during
 * packing process. CONTINUATION frames are also serialized in this
 * function. This function does not handle padding.
 *
 * This function returns 0 if it succeeds, or returns one of the
 * following negative error codes:
 *
 * NGHTTP2_ERR_HEADER_COMP
 *     The deflate operation failed.
 * NGHTTP2_ERR_FRAME_SIZE_ERROR
 *     The length of the frame is too large.
 * NGHTTP2_ERR_NOMEM
 *     Out of memory.
 */
int nghttp2_frame_pack_headers(nghttp2_bufs *bufs,
                               nghttp2_headers *frame,
                               nghttp2_hd_deflater *deflater);

/*
 * Unpacks HEADERS frame byte sequence into |frame|. This function
 * only unapcks bytes that come before name/value header block.
 *
 * This function returns 0 if it succeeds or one of the following
 * negative error codes:
 *
 * NGHTTP2_ERR_PROTO
 *     TODO END_HEADERS flag is not set
 */
int nghttp2_frame_unpack_headers_payload(nghttp2_headers *frame,
                                         const uint8_t *payload,
                                         size_t payloadlen);

/*
 * Packs PRIORITY frame |frame| in wire format and store it in
 * |bufs|.
 *
 * The caller must make sure that nghttp2_bufs_reset(bufs) is called
 * before calling this function.
 *
 * This function returns 0 if it succeeds or one of the following
 * negative error codes:
 *
 * NGHTTP2_ERR_NOMEM
 *     Out of memory.
 */
int nghttp2_frame_pack_priority(nghttp2_bufs *bufs,
                                nghttp2_priority *frame);

/*
 * Unpacks PRIORITY wire format into |frame|.
 */
void nghttp2_frame_unpack_priority_payload(nghttp2_priority *frame,
                                           const uint8_t *payload,
                                           size_t payloadlen);

/*
 * Packs RST_STREAM frame |frame| in wire frame format and store it in
 * |bufs|.
 *
 * The caller must make sure that nghttp2_bufs_reset(bufs) is called
 * before calling this function.
 *
 * This function returns 0 if it succeeds, or returns one of the
 * following negative error codes:
 *
 * NGHTTP2_ERR_NOMEM
 *     Out of memory.
 */
int nghttp2_frame_pack_rst_stream(nghttp2_bufs *bufs,
                                  nghttp2_rst_stream *frame);

/*
 * Unpacks RST_STREAM frame byte sequence into |frame|.
 */
void nghttp2_frame_unpack_rst_stream_payload(nghttp2_rst_stream *frame,
                                             const uint8_t *payload,
                                             size_t payloadlen);

/*
 * Packs SETTINGS frame |frame| in wire format and store it in
 * |bufs|.
 *
 * The caller must make sure that nghttp2_bufs_reset(bufs) is called
 * before calling this function.
 *
 * This function returns 0 if it succeeds, or returns one of the
 * following negative error codes:
 *
 * NGHTTP2_ERR_NOMEM
 *     Out of memory.
 * NGHTTP2_ERR_FRAME_SIZE_ERROR
 *     The length of the frame is too large.
 */
int nghttp2_frame_pack_settings(nghttp2_bufs *bufs, nghttp2_settings *frame);

/*
 * Packs the |iv|, which includes |niv| entries, in the |buf|,
 * assuming the |buf| has at least 8 * |niv| bytes.
 *
 * Returns the number of bytes written into the |buf|.
 */
size_t nghttp2_frame_pack_settings_payload(uint8_t *buf,
                                           const nghttp2_settings_entry *iv,
                                           size_t niv);

void nghttp2_frame_unpack_settings_entry(nghttp2_settings_entry *iv,
                                         const uint8_t *payload);

/*
 * Makes a copy of |iv| in frame->settings.iv. The |niv| is assigned
 * to frame->settings.niv.
 *
 * This function returns 0 if it succeeds or one of the following
 * negative error codes:
 *
 * NGHTTP2_ERR_NOMEM
 *     Out of memory.
 */
int nghttp2_frame_unpack_settings_payload(nghttp2_settings *frame,
                                          nghttp2_settings_entry *iv,
                                          size_t niv);

/*
 * Unpacks SETTINGS payload into |*iv_ptr|. The number of entries are
 * assigned to the |*niv_ptr|. This function allocates enough memory
 * to store the result in |*iv_ptr|. The caller is responsible to free
 * |*iv_ptr| after its use.
 *
 * This function returns 0 if it succeeds or one of the following
 * negative error codes:
 *
 * NGHTTP2_ERR_NOMEM
 *     Out of memory.
 */
int nghttp2_frame_unpack_settings_payload2(nghttp2_settings_entry **iv_ptr,
                                           size_t *niv_ptr,
                                           const uint8_t *payload,
                                           size_t payloadlen);

/*
 * Packs PUSH_PROMISE frame |frame| in wire format and store it in
 * |bufs|.  This function expands |bufs| as necessary to store
 * frame.
 *
 * The caller must make sure that nghttp2_bufs_reset(bufs) is called
 * before calling this function.
 *
 * frame->hd.length is assigned after length is determined during
 * packing process. CONTINUATION frames are also serialized in this
 * function. This function does not handle padding.
 *
 * This function returns 0 if it succeeds, or returns one of the
 * following negative error codes:
 *
 * NGHTTP2_ERR_HEADER_COMP
 *     The deflate operation failed.
 * NGHTTP2_ERR_FRAME_SIZE_ERROR
 *     The length of the frame is too large.
 * NGHTTP2_ERR_NOMEM
 *     Out of memory.
 */
int nghttp2_frame_pack_push_promise(nghttp2_bufs *bufs,
                                    nghttp2_push_promise *frame,
                                    nghttp2_hd_deflater *deflater);

/*
 * Unpacks PUSH_PROMISE frame byte sequence into |frame|. This function
 * only unapcks bytes that come before name/value header block.
 *
 * This function returns 0 if it succeeds or one of the following
 * negative error codes:
 *
 * NGHTTP2_ERR_PROTO
 *     TODO END_HEADERS flag is not set
 */
int nghttp2_frame_unpack_push_promise_payload(nghttp2_push_promise *frame,
                                              const uint8_t *payload,
                                              size_t payloadlen);

/*
 * Packs PING frame |frame| in wire format and store it in
 * |bufs|.
 *
 * The caller must make sure that nghttp2_bufs_reset(bufs) is called
 * before calling this function.
 *
 * This function returns 0 if it succeeds or one of the following
 * negative error codes:
 *
 * NGHTTP2_ERR_NOMEM
 *     Out of memory.
 */
int nghttp2_frame_pack_ping(nghttp2_bufs *bufs, nghttp2_ping *frame);

/*
 * Unpacks PING wire format into |frame|.
 */
void nghttp2_frame_unpack_ping_payload(nghttp2_ping *frame,
                                       const uint8_t *payload,
                                       size_t payloadlen);

/*
 * Packs GOAWAY frame |frame| in wire format and store it in |bufs|.
 * This function expands |bufs| as necessary to store frame.
 *
 * The caller must make sure that nghttp2_bufs_reset(bufs) is called
 * before calling this function.
 *
 * This function returns 0 if it succeeds or one of the following
 * negative error codes:
 *
 * NGHTTP2_ERR_NOMEM
 *     Out of memory.
 * NGHTTP2_ERR_FRAME_SIZE_ERROR
 *     The length of the frame is too large.
 */
int nghttp2_frame_pack_goaway(nghttp2_bufs *bufs, nghttp2_goaway *frame);

/*
 * Unpacks GOAWAY wire format into |frame|.  The |payload| of length
 * |payloadlen| contains first 8 bytes of payload.  The
 * |var_gift_payload| of length |var_gift_payloadlen| contains
 * remaining payload and its buffer is gifted to the function and then
 * |frame|.  The |var_gift_payloadlen| must be freed by
 * nghttp2_frame_goaway_free().
 */
void nghttp2_frame_unpack_goaway_payload(nghttp2_goaway *frame,
                                         const uint8_t *payload,
                                         size_t payloadlen,
                                         uint8_t *var_gift_payload,
                                         size_t var_gift_payloadlen);

/*
 * Unpacks GOAWAY wire format into |frame|.  This function only exists
 * for unit test.  After allocating buffer for debug data, this
 * function internally calls nghttp2_frame_unpack_goaway_payload().
 *
 * This function returns 0 if it succeeds, or one of the following
 * negative error codes:
 *
 * NGHTTP2_ERR_NOMEM
 *     Out of memory.
 */
int nghttp2_frame_unpack_goaway_payload2(nghttp2_goaway *frame,
                                         const uint8_t *payload,
                                         size_t payloadlen);

/*
 * Packs WINDOW_UPDATE frame |frame| in wire frame format and store it
 * in |bufs|.
 *
 * The caller must make sure that nghttp2_bufs_reset(bufs) is called
 * before calling this function.
 *
 * This function returns 0 if it succeeds, or returns one of the
 * following negative error codes:
 *
 * NGHTTP2_ERR_NOMEM
 *     Out of memory.
 */
int nghttp2_frame_pack_window_update(nghttp2_bufs *bufs,
                                     nghttp2_window_update *frame);

/*
 * Unpacks WINDOW_UPDATE frame byte sequence into |frame|.
 */
void nghttp2_frame_unpack_window_update_payload(nghttp2_window_update *frame,
                                                const uint8_t *payload,
                                                size_t payloadlen);

/*
 * Initializes HEADERS frame |frame| with given values.  |frame| takes
 * ownership of |nva|, so caller must not free it. If |stream_id| is
 * not assigned yet, it must be -1.
 */
void nghttp2_frame_headers_init(nghttp2_headers *frame,
                                uint8_t flags, int32_t stream_id,
                                const nghttp2_priority_spec *pri_spec,
                                nghttp2_nv *nva, size_t nvlen);

void nghttp2_frame_headers_free(nghttp2_headers *frame);


void nghttp2_frame_priority_init(nghttp2_priority *frame, int32_t stream_id,
                                 const nghttp2_priority_spec *pri_spec);

void nghttp2_frame_priority_free(nghttp2_priority *frame);

void nghttp2_frame_rst_stream_init(nghttp2_rst_stream *frame,
                                   int32_t stream_id,
                                   nghttp2_error_code error_code);

void nghttp2_frame_rst_stream_free(nghttp2_rst_stream *frame);

/*
 * Initializes PUSH_PROMISE frame |frame| with given values.  |frame|
 * takes ownership of |nva|, so caller must not free it.
 */
void nghttp2_frame_push_promise_init(nghttp2_push_promise *frame,
                                     uint8_t flags, int32_t stream_id,
                                     int32_t promised_stream_id,
                                     nghttp2_nv *nva, size_t nvlen);

void nghttp2_frame_push_promise_free(nghttp2_push_promise *frame);

/*
 * Initializes SETTINGS frame |frame| with given values. |frame| takes
 * ownership of |iv|, so caller must not free it. The |flags| are
 * bitwise-OR of one or more of nghttp2_settings_flag.
 */
void nghttp2_frame_settings_init(nghttp2_settings *frame, uint8_t flags,
                                 nghttp2_settings_entry *iv, size_t niv);

void nghttp2_frame_settings_free(nghttp2_settings *frame);

/*
 * Initializes PING frame |frame| with given values. If the
 * |opqeue_data| is not NULL, it must point to 8 bytes memory region
 * of data. The data pointed by |opaque_data| is copied. It can be
 * NULL. In this case, 8 bytes NULL is used.
 */
void nghttp2_frame_ping_init(nghttp2_ping *frame, uint8_t flags,
                             const uint8_t *opque_data);

void nghttp2_frame_ping_free(nghttp2_ping *frame);

/*
 * Initializes GOAWAY frame |frame| with given values. On success,
 * this function takes ownership of |opaque_data|, so caller must not
 * free it. If the |opaque_data_len| is 0, opaque_data could be NULL.
 */
void nghttp2_frame_goaway_init(nghttp2_goaway *frame, int32_t last_stream_id,
                               nghttp2_error_code error_code,
                               uint8_t *opaque_data, size_t opaque_data_len);

void nghttp2_frame_goaway_free(nghttp2_goaway *frame);

void nghttp2_frame_window_update_init(nghttp2_window_update *frame,
                                      uint8_t flags,
                                      int32_t stream_id,
                                      int32_t window_size_increment);

void nghttp2_frame_window_update_free(nghttp2_window_update *frame);

void nghttp2_frame_data_init(nghttp2_data *frame, nghttp2_private_data *pdata);

/*
 * Returns the number of padding bytes after payload. The total
 * padding length is given in the |padlen|. The returned value does
 * not include the PAD_HIGH and PAD_LOW.
 */
size_t nghttp2_frame_trail_padlen(nghttp2_frame *frame, size_t padlen);

void nghttp2_frame_private_data_init(nghttp2_private_data *frame,
                                     uint8_t flags,
                                     int32_t stream_id,
                                     const nghttp2_data_provider *data_prd);

void nghttp2_frame_private_data_free(nghttp2_private_data *frame);

/*
 * Makes copy of |iv| and return the copy. The |niv| is the number of
 * entries in |iv|. This function returns the pointer to the copy if
 * it succeeds, or NULL.
 */
nghttp2_settings_entry* nghttp2_frame_iv_copy(const nghttp2_settings_entry *iv,
                                              size_t niv);

/*
 * Sorts the |nva| in ascending order of name and value. If names are
 * equivalent, sort them by value.
 */
void nghttp2_nv_array_sort(nghttp2_nv *nva, size_t nvlen);

/*
 * Copies name/value pairs from |nva|, which contains |nvlen| pairs,
 * to |*nva_ptr|, which is dynamically allocated so that all items can
 * be stored.
 *
 * The |*nva_ptr| must be freed using nghttp2_nv_array_del().
 *
 * This function returns the number of name/value pairs in |*nva_ptr|,
 * or one of the following negative error codes:
 *
 * NGHTTP2_ERR_NOMEM
 *     Out of memory.
 */
ssize_t nghttp2_nv_array_copy(nghttp2_nv **nva_ptr,
                              const nghttp2_nv *nva, size_t nvlen);

/*
 * Returns nonzero if the name/value pair |a| equals to |b|. The name
 * is compared in case-sensitive, because we ensure that this function
 * is called after the name is lower-cased.
 */
int nghttp2_nv_equal(const nghttp2_nv *a, const nghttp2_nv *b);

/*
 * Frees |nva|.
 */
void nghttp2_nv_array_del(nghttp2_nv *nva);

/*
 * Checks that the |iv|, which includes |niv| entries, does not have
 * invalid values.
 *
 * This function returns nonzero if it succeeds, or 0.
 */
int nghttp2_iv_check(const nghttp2_settings_entry *iv, size_t niv);

/*
 * Sets PAD_HIGH and PAD_LOW fields, flags and adjust frame header
 * position of each buffers in |bufs|.  The padding is given in the
 * |padlen|. The |hd| is the frame header for the serialized data.
 * The |type| is used as a frame type when padding requires additional
 * buffers.
 *
 * This function returns 0 if it succeeds, or one of the following
 * negative error codes:
 *
 * NGHTTP2_ERR_NOMEM
 *     Out of memory.
 * NGHTTP2_ERR_BUFFER_ERROR
 *     Out of buffer space. This is not a fatal.
 */
int nghttp2_frame_add_pad(nghttp2_bufs *bufs, nghttp2_frame_hd *hd,
                          size_t padlen, nghttp2_frame_type type);

#endif /* NGHTTP2_FRAME_H */