text: /*
   * 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_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 9
  
  #define NGHTTP2_MAX_FRAME_SIZE_MAX ((1 << 24) - 1)
  #define NGHTTP2_MAX_FRAME_SIZE_MIN (1 << 14)
  
  #define NGHTTP2_MAX_PAYLOADLEN 16384
  /* The one frame buffer length for tranmission.  We may use several of
     them to support CONTINUATION.  To account for Pad Length field, we
     allocate extra 1 byte, which saves extra large memcopying. */
  #define NGHTTP2_FRAMEBUF_CHUNKLEN                                              \
    (NGHTTP2_FRAME_HDLEN + 1 + NGHTTP2_MAX_PAYLOADLEN)
  
  /* The default length of DATA frame payload. */
  #define NGHTTP2_DATA_PAYLOADLEN NGHTTP2_MAX_FRAME_SIZE_MIN
  
  /* Maximum headers block size to send, calculated using
     nghttp2_hd_deflate_bound().  This is the default value, and can be
     overridden by nghttp2_option_set_max_send_header_block_size(). */
  #define NGHTTP2_MAX_HEADERSLEN 65536
  
  /* The number of bytes for each SETTINGS entry */
  #define NGHTTP2_FRAME_SETTINGS_ENTRY_LENGTH 6
  
  /* Length of priority related fields in HEADERS/PRIORITY frames */
  #define NGHTTP2_PRIORITY_SPECLEN 5
  
  /* Maximum length of padding in bytes. */
  #define NGHTTP2_MAX_PADLEN 256
  
  /* Union of extension frame payload */
  typedef union {
    nghttp2_ext_altsvc altsvc;
  } nghttp2_ext_frame_payload;
  
  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);
  
  /**
   * Initializes frame header |hd| with given parameters.  Reserved bit
   * is set to 0.
   */
  void nghttp2_frame_hd_init(nghttp2_frame_hd *hd, size_t length, uint8_t type,
                             uint8_t flags, int32_t stream_id);
  
  /**
   * 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,
                                          const uint8_t *payload);
  
  /*
   * 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_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 and
   * after possible Pad Length field.
   *
   * This function always succeeds and returns 0.
   */
  int nghttp2_frame_unpack_headers_payload(nghttp2_headers *frame,
                                           const uint8_t *payload);
  
  /*
   * 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 always succeeds and returns 0.
   */
  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);
  
  /*
   * 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 always succeeds and returns 0.
   */
  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);
  
  /*
   * 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_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);
  
  /*
   * Initializes payload of frame->settings.  The |frame| takes
   * ownership of |iv|.
   */
  void 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, nghttp2_mem *mem);
  
  /*
   * 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_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 and after possible Pad Length field.
   *
   * 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);
  
  /*
   * 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 always succeeds and returns 0.
   */
  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);
  
  /*
   * 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,
                                           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, nghttp2_mem *mem);
  
  /*
   * 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 always succeeds and returns 0.
   */
  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);
  
  /*
   * Packs ALTSVC 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 always succeeds and returns 0.
   */
  int nghttp2_frame_pack_altsvc(nghttp2_bufs *bufs, nghttp2_extension *ext);
  
  /*
   * Unpacks ALTSVC wire format into |frame|.  The |payload| of
   * |payloadlen| bytes contains frame payload.  This function assumes
   * that frame->payload points to the nghttp2_ext_altsvc object.
   *
   * This function always succeeds and returns 0.
   */
  void nghttp2_frame_unpack_altsvc_payload(nghttp2_extension *frame,
                                           size_t origin_len, uint8_t *payload,
                                           size_t payloadlen);
  
  /*
   * Unpacks ALTSVC wire format into |frame|.  This function only exists
   * for unit test.  After allocating buffer for fields, this function
   * internally calls nghttp2_frame_unpack_altsvc_payload().
   *
   * 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 payload is too small.
   */
  int nghttp2_frame_unpack_altsvc_payload2(nghttp2_extension *frame,
                                           const uint8_t *payload,
                                           size_t payloadlen, nghttp2_mem *mem);
  
  /*
   * 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, nghttp2_headers_category cat,
                                  const nghttp2_priority_spec *pri_spec,
                                  nghttp2_nv *nva, size_t nvlen);
  
  void nghttp2_frame_headers_free(nghttp2_headers *frame, nghttp2_mem *mem);
  
  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,
                                     uint32_t 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,
                                       nghttp2_mem *mem);
  
  /*
   * 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, nghttp2_mem *mem);
  
  /*
   * 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,
                                 uint32_t error_code, uint8_t *opaque_data,
                                 size_t opaque_data_len);
  
  void nghttp2_frame_goaway_free(nghttp2_goaway *frame, nghttp2_mem *mem);
  
  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_extension_init(nghttp2_extension *frame, uint8_t type,
                                    uint8_t flags, int32_t stream_id,
                                    void *payload);
  
  void nghttp2_frame_extension_free(nghttp2_extension *frame);
  
  /*
   * Initializes ALTSVC frame |frame| with given values.  This function
   * assumes that frame->payload points to nghttp2_ext_altsvc object.
   * Also |origin| and |field_value| are allocated in single buffer,
   * starting |origin|.  On success, this function takes ownership of
   * |origin|, so caller must not free it.
   */
  void nghttp2_frame_altsvc_init(nghttp2_extension *frame, int32_t stream_id,
                                 uint8_t *origin, size_t origin_len,
                                 uint8_t *field_value, size_t field_value_len);
  
  /*
   * Frees up resources under |frame|.  This function does not free
   * nghttp2_ext_altsvc object pointed by frame->payload.  This function
   * only frees origin pointed by nghttp2_ext_altsvc.origin.  Therefore,
   * other fields must be allocated in the same buffer with origin.
   */
  void nghttp2_frame_altsvc_free(nghttp2_extension *frame, nghttp2_mem *mem);
  
  /*
   * 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 Length field.  If |padlen| is 0, this function
   * returns 0, regardless of frame->hd.flags.
   */
  size_t nghttp2_frame_trail_padlen(nghttp2_frame *frame, size_t padlen);
  
  void nghttp2_frame_data_init(nghttp2_data *frame, uint8_t flags,
                               int32_t stream_id);
  
  void nghttp2_frame_data_free(nghttp2_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, nghttp2_mem *mem);
  
  /*
   * 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 resultant name and value in nghttp2_nv are
   * guaranteed to be NULL-terminated even if the input is not
   * null-terminated.
   *
   * The |*nva_ptr| must be freed using nghttp2_nv_array_del().
   *
   * This function returns 0 if it succeeds or one of the following
   * negative error codes:
   *
   * NGHTTP2_ERR_NOMEM
   *     Out of memory.
   */
  int nghttp2_nv_array_copy(nghttp2_nv **nva_ptr, const nghttp2_nv *nva,
                            size_t nvlen, nghttp2_mem *mem);
  
  /*
   * 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, nghttp2_mem *mem);
  
  /*
   * 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 Length field and flags and adjusts frame header position
   * of each buffers in |bufs|.  The number of padding is given in the
   * |padlen| including Pad Length field.  The |hd| is the frame header
   * for the serialized data.  This function fills zeros padding region
   * unless framehd_only is nonzero.
   *
   * 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 resulting frame is too large.
   */
  int nghttp2_frame_add_pad(nghttp2_bufs *bufs, nghttp2_frame_hd *hd,
                            size_t padlen, int framehd_only);
  
  #endif /* NGHTTP2_FRAME_H */
  