nghttp2/lib/nghttp2_hd.h

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/*
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* nghttp2 - HTTP/2 C Library
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*
* Copyright (c) 2013 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_HD_H
#define NGHTTP2_HD_H
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#ifdef HAVE_CONFIG_H
# include <config.h>
#endif /* HAVE_CONFIG_H */
#include <nghttp2/nghttp2.h>
#include "nghttp2_hd_huffman.h"
#include "nghttp2_buf.h"
#define NGHTTP2_HD_DEFAULT_MAX_BUFFER_SIZE (1 << 12)
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#define NGHTTP2_HD_ENTRY_OVERHEAD 32
/* The maximum value length of name/value pair. This is not specified
by the spec. We just chose the arbitrary size */
#define NGHTTP2_HD_MAX_NAME 256
#define NGHTTP2_HD_MAX_VALUE 8192
#define NGHTTP2_HD_MAX_BUFFER_LENGTH (1 << 15)
/* Default size of maximum table buffer size for encoder. Even if
remote decoder notifies larger buffer size for its decoding,
encoder only uses the memory up to this value. */
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#define NGHTTP2_HD_DEFAULT_MAX_DEFLATE_BUFFER_SIZE (1 << 12)
typedef enum {
NGHTTP2_HD_ROLE_DEFLATE,
NGHTTP2_HD_ROLE_INFLATE
} nghttp2_hd_role;
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typedef enum {
NGHTTP2_HD_FLAG_NONE = 0,
/* Indicates name was dynamically allocated and must be freed */
NGHTTP2_HD_FLAG_NAME_ALLOC = 1,
/* Indicates value was dynamically allocated and must be freed */
NGHTTP2_HD_FLAG_VALUE_ALLOC = 1 << 1,
/* Indicates that the entry is in the reference set */
NGHTTP2_HD_FLAG_REFSET = 1 << 2,
/* Indicates that the entry is emitted in the current header
processing. */
NGHTTP2_HD_FLAG_EMIT = 1 << 3,
NGHTTP2_HD_FLAG_IMPLICIT_EMIT = 1 << 4,
/* Indicates that the name was gifted to the entry and no copying
necessary. */
NGHTTP2_HD_FLAG_NAME_GIFT = 1 << 5,
/* Indicates that the value was gifted to the entry and no copying
necessary. */
NGHTTP2_HD_FLAG_VALUE_GIFT = 1 << 6
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} nghttp2_hd_flags;
typedef struct {
nghttp2_nv nv;
uint32_t name_hash;
uint32_t value_hash;
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/* Reference count */
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uint8_t ref;
uint8_t flags;
} nghttp2_hd_entry;
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typedef struct {
nghttp2_hd_entry ent;
size_t index;
} nghttp2_hd_static_entry;
typedef struct {
nghttp2_hd_entry **buffer;
size_t mask;
size_t first;
size_t len;
} nghttp2_hd_ringbuf;
typedef enum {
NGHTTP2_HD_OPCODE_NONE,
NGHTTP2_HD_OPCODE_INDEXED,
NGHTTP2_HD_OPCODE_NEWNAME,
NGHTTP2_HD_OPCODE_INDNAME
} nghttp2_hd_opcode;
typedef enum {
NGHTTP2_HD_STATE_OPCODE,
NGHTTP2_HD_STATE_CLEAR_REFSET,
NGHTTP2_HD_STATE_READ_TABLE_SIZE,
NGHTTP2_HD_STATE_READ_INDEX,
NGHTTP2_HD_STATE_NEWNAME_CHECK_NAMELEN,
NGHTTP2_HD_STATE_NEWNAME_READ_NAMELEN,
NGHTTP2_HD_STATE_NEWNAME_READ_NAMEHUFF,
NGHTTP2_HD_STATE_NEWNAME_READ_NAME,
NGHTTP2_HD_STATE_CHECK_VALUELEN,
NGHTTP2_HD_STATE_READ_VALUELEN,
NGHTTP2_HD_STATE_READ_VALUEHUFF,
NGHTTP2_HD_STATE_READ_VALUE,
} nghttp2_hd_inflate_state;
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typedef struct {
/* dynamic header table */
nghttp2_hd_ringbuf hd_table;
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/* Abstract buffer size of hd_table as described in the spec. This
is the sum of length of name/value in hd_table +
NGHTTP2_HD_ENTRY_OVERHEAD bytes overhead per each entry. */
size_t hd_table_bufsize;
/* The effective header table size. */
size_t hd_table_bufsize_max;
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/* Role of this context; deflate or infalte */
nghttp2_hd_role role;
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/* If inflate/deflate error occurred, this value is set to 1 and
further invocation of inflate/deflate will fail with
NGHTTP2_ERR_HEADER_COMP. */
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uint8_t bad;
} nghttp2_hd_context;
typedef struct {
nghttp2_hd_context ctx;
/* The upper limit of the header table size the deflater accepts. */
size_t deflate_hd_table_bufsize_max;
/* Set to this nonzero to clear reference set on each deflation each
time. */
uint8_t no_refset;
} nghttp2_hd_deflater;
typedef struct {
nghttp2_hd_context ctx;
/* header name buffer */
nghttp2_bufs namebufs;
/* header value buffer */
nghttp2_bufs valuebufs;
/* Stores current state of huffman decoding */
nghttp2_hd_huff_decode_context huff_decode_ctx;
/* Pointer to the nghttp2_hd_entry which is used current header
emission. This is required because in some cases the
ent_keep->ref == 0 and we have to keep track of it. */
nghttp2_hd_entry *ent_keep;
/* Pointers to the name/value pair which are used current header
emission. They are usually used to keep track of malloc'ed memory
for huffman decoding. */
uint8_t *name_keep, *value_keep;
/* Pointers to the name/value pair which is referred as indexed
name. This entry must be in header table. */
nghttp2_hd_entry *ent_name;
/* The number of bytes to read */
ssize_t left;
/* The index in indexed repr or indexed name */
size_t index;
/* The index of header table to toggle off the entry from reference
set at the end of decompression. */
size_t end_headers_index;
/* The maximum header table size the inflater supports. This is the
same value transmitted in SETTINGS_HEADER_TABLE_SIZE */
size_t settings_hd_table_bufsize_max;
nghttp2_hd_opcode opcode;
nghttp2_hd_inflate_state state;
/* nonzero if string is huffman encoded */
uint8_t huffman_encoded;
/* nonzero if deflater requires that current entry is indexed */
uint8_t index_required;
/* nonzero if deflater requires that current entry must not be
indexed */
uint8_t no_index;
} nghttp2_hd_inflater;
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/*
* Initializes the |ent| members. If NGHTTP2_HD_FLAG_NAME_ALLOC bit
* set in the |flags|, the content pointed by the |name| with length
* |namelen| is copied. Likewise, if NGHTTP2_HD_FLAG_VALUE_ALLOC bit
* set in the |flags|, the content pointed by the |value| with length
* |valuelen| is copied.
*
* This function returns 0 if it succeeds, or one of the following
* negative error codes:
*
* NGHTTP2_ERR_NOMEM
* Out of memory.
*/
int nghttp2_hd_entry_init(nghttp2_hd_entry *ent, uint8_t flags,
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uint8_t *name, uint16_t namelen,
uint8_t *value, uint16_t valuelen);
void nghttp2_hd_entry_free(nghttp2_hd_entry *ent);
/*
* Initializes |deflater| for deflating name/values pairs.
*
* The encoder only uses up to
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* NGHTTP2_HD_DEFAULT_MAX_DEFLATE_BUFFER_SIZE bytes for header table
* even if the larger value is specified later in
* nghttp2_hd_change_table_size().
*
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* This function returns 0 if it succeeds, or one of the following
* negative error codes:
*
* NGHTTP2_ERR_NOMEM
* Out of memory.
*/
int nghttp2_hd_deflate_init(nghttp2_hd_deflater *deflater);
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/*
* Initializes |deflater| for deflating name/values pairs.
*
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* The encoder only uses up to |deflate_hd_table_bufsize_max| bytes
* for header table even if the larger value is specified later in
* nghttp2_hd_change_table_size().
*
* This function returns 0 if it succeeds, or one of the following
* negative error codes:
*
* NGHTTP2_ERR_NOMEM
* Out of memory.
*/
int nghttp2_hd_deflate_init2(nghttp2_hd_deflater *deflater,
size_t deflate_hd_table_bufsize_max);
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/*
* Initializes |inflater| for inflating name/values pairs.
*
* This function returns 0 if it succeeds, or one of the following
* negative error codes:
*
* NGHTTP2_ERR_NOMEM
* Out of memory.
*/
int nghttp2_hd_inflate_init(nghttp2_hd_inflater *inflater);
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/*
* Deallocates any resources allocated for |deflater|.
*/
void nghttp2_hd_deflate_free(nghttp2_hd_deflater *deflater);
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/*
* Deallocates any resources allocated for |inflater|.
*/
void nghttp2_hd_inflate_free(nghttp2_hd_inflater *inflater);
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/*
* Sets the availability of reference set in the |deflater|. If
* |no_refset| is nonzero, the deflater will first emit index=0 in the
* each invocation of nghttp2_hd_deflate_hd() to clear up reference
* set. By default, the deflater uses reference set.
*/
void nghttp2_hd_deflate_set_no_refset(nghttp2_hd_deflater *deflater,
uint8_t no_refset);
/*
* Changes header table size of the |deflater|. This may trigger
* eviction in the dynamic table.
*
* The |settings_hd_table_bufsize_max| should be the value received in
* SETTINGS_HEADER_TABLE_SIZE.
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*
* This function returns 0 if it succeeds, or one of the following
* negative error codes:
*
* NGHTTP2_ERR_NOMEM
* Out of memory.
*/
int nghttp2_hd_deflate_change_table_size(nghttp2_hd_deflater *deflater,
size_t settings_hd_table_bufsize_max);
/*
* Changes header table size in the |inflater|. This may trigger
* eviction in the dynamic table.
*
* The |settings_hd_table_bufsize_max| should be the value transmitted
* in SETTINGS_HEADER_TABLE_SIZE.
*
* This function returns 0 if it succeeds, or one of the following
* negative error codes:
*
* NGHTTP2_ERR_NOMEM
* Out of memory.
*/
int nghttp2_hd_inflate_change_table_size(nghttp2_hd_inflater *inflater,
size_t settings_hd_table_bufsize_max);
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/*
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* Deflates the |nva|, which has the |nvlen| name/value pairs, into
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* the |bufs|.
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*
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* This function expands |bufs| as necessary to store the result. If
* buffers is full and the process still requires more space, this
* funtion fails and returns NGHTTP2_ERR_HEADER_COMP.
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*
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* After this function returns, it is safe to delete the |nva|.
*
* TODO: The rest of the code call nghttp2_hd_end_headers() after this
* call, but it is just a regacy of the first implementation. Now it
* is not required to be called as of now.
*
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* This function returns 0 if it succeeds, or one of the following
* negative error codes:
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*
* NGHTTP2_ERR_NOMEM
* Out of memory.
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* NGHTTP2_ERR_HEADER_COMP
* Deflation process has failed.
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*/
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int nghttp2_hd_deflate_hd(nghttp2_hd_deflater *deflater,
nghttp2_bufs *bufs,
nghttp2_nv *nva, size_t nvlen);
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typedef enum {
NGHTTP2_HD_INFLATE_NONE = 0,
NGHTTP2_HD_INFLATE_FINAL = 1,
NGHTTP2_HD_INFLATE_EMIT = (1 << 1)
} nghttp2_hd_inflate_flag;
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/*
* Inflates name/value block stored in |in| with length |inlen|. This
* function performs decompression. For each successful emission of
* header name/value pair, NGHTTP2_HD_INFLATE_EMIT is set in
* |*inflate_flags| and name/value pair is assigned to the |nv_out|
* and the function returns. The caller must not free the members of
* |nv_out|.
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*
* The |nv_out| may include pointers to the memory region in the
* |in|. The caller must retain the |in| while the |nv_out| is used.
*
* The application should call this function repeatedly until the
* |(*inflate_flags) & NGHTTP2_HD_INFLATE_FINAL| is nonzero and return
* value is non-negative. This means the all input values are
* processed successfully. Then the application must call
* `nghttp2_hd_inflate_end_headers()` to prepare for the next header
* block input.
*
* The caller can feed complete compressed header block. It also can
* feed it in several chunks. The caller must set |in_final| to
* nonzero if the given input is the last block of the compressed
* header.
*
* This function returns the number of bytes processed if it succeeds,
* or one of the following negative error codes:
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*
* NGHTTP2_ERR_NOMEM
* Out of memory.
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* NGHTTP2_ERR_HEADER_COMP
* Inflation process has failed.
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*/
ssize_t nghttp2_hd_inflate_hd(nghttp2_hd_inflater *inflater,
nghttp2_nv *nv_out, int *inflate_flags,
uint8_t *in, size_t inlen, int in_final);
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/*
* Signals the end of decompression for one header block.
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*
* This function returns 0 if it succeeds. Currently this function
* always succeeds.
*/
int nghttp2_hd_inflate_end_headers(nghttp2_hd_inflater *inflater);
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/* For unittesting purpose */
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int nghttp2_hd_emit_indname_block(nghttp2_bufs *bufs, size_t index,
nghttp2_nv *nv, int inc_indexing);
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/* For unittesting purpose */
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int nghttp2_hd_emit_newname_block(nghttp2_bufs *bufs, nghttp2_nv *nv,
int inc_indexing);
/* For unittesting purpose */
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int nghttp2_hd_emit_table_size(nghttp2_bufs *bufs, size_t table_size);
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/* For unittesting purpose */
nghttp2_hd_entry* nghttp2_hd_table_get(nghttp2_hd_context *context,
size_t index);
/* Huffman encoding/decoding functions */
/*
* Counts the required bytes to encode |src| with length |len|.
*
* This function returns the number of required bytes to encode given
* data, including padding of prefix of terminal symbol code. This
* function always succeeds.
*/
size_t nghttp2_hd_huff_encode_count(const uint8_t *src, size_t len);
/*
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* Encodes the given data |src| with length |srclen| to the |bufs|.
* This function expands extra buffers in |bufs| if necessary.
*
* 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.
*/
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int nghttp2_hd_huff_encode(nghttp2_bufs *bufs,
const uint8_t *src, size_t srclen);
void nghttp2_hd_huff_decode_context_init(nghttp2_hd_huff_decode_context *ctx);
/*
* Decodes the given data |src| with length |srclen|. The |ctx| must
* be initialized by nghttp2_hd_huff_decode_context_init(). The result
* will be added to |dest|. This function may expand |dest| as
* needed. The caller is responsible to release the memory of |dest|
* by calling nghttp2_bufs_free() or export its content using
* nghttp2_bufs_remove().
*
* The caller must set the |final| to nonzero if the given input is
* the final block.
*
* This function returns the number of read bytes from the |in|.
*
* If this function fails, it returns one of the following negative
* return codes:
*
* NGHTTP2_ERR_NOMEM
* Out of memory.
* NGHTTP2_ERR_BUFFER_ERROR
* Maximum buffer capacity size exceeded.
* NGHTTP2_ERR_HEADER_COMP
* Decoding process has failed.
*/
ssize_t nghttp2_hd_huff_decode(nghttp2_hd_huff_decode_context *ctx,
nghttp2_bufs *bufs,
const uint8_t *src, size_t srclen, int final);
#endif /* NGHTTP2_HD_H */