Adding upstream version 0.8.0.upstream/0.8.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

4 files changed, 2722 insertions, 0 deletions

diff --git a/lib/includes/CMakeLists.txt b/lib/includes/CMakeLists.txt
new file mode 100644
index 0000000..76d7364
--- /dev/null
+++ b/lib/includes/CMakeLists.txt
@@ -0,0 +1,4 @@
+install(FILES
+    nghttp3/nghttp3.h
+    "${CMAKE_CURRENT_BINARY_DIR}/nghttp3/version.h"
+  DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/nghttp3")
diff --git a/lib/includes/Makefile.am b/lib/includes/Makefile.am
new file mode 100644
index 0000000..b69d2fc
--- /dev/null
+++ b/lib/includes/Makefile.am
@@ -0,0 +1,26 @@
+# nghttp3
+#
+# Copyright (c) 2019 nghttp3 contributors
+# Copyright (c) 2016 ngtcp2 contributors
+#
+# 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.
+EXTRA_DIST = CMakeLists.txt
+
+nobase_include_HEADERS = nghttp3/nghttp3.h nghttp3/version.h
diff --git a/lib/includes/nghttp3/nghttp3.h b/lib/includes/nghttp3/nghttp3.h
new file mode 100644
index 0000000..7986ea8
--- /dev/null
+++ b/lib/includes/nghttp3/nghttp3.h
@@ -0,0 +1,2646 @@
+/*
+ * nghttp3
+ *
+ * Copyright (c) 2018 nghttp3 contributors
+ * Copyright (c) 2017 ngtcp2 contributors
+ * Copyright (c) 2017 nghttp2 contributors
+ *
+ * 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 NGHTTP3_H
+#define NGHTTP3_H
+
+/* Define WIN32 when build target is Win32 API (borrowed from
+   libcurl) */
+#if (defined(_WIN32) || defined(__WIN32__)) && !defined(WIN32)
+#  define WIN32
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdlib.h>
+#if defined(_MSC_VER) && (_MSC_VER < 1800)
+/* MSVC < 2013 does not have inttypes.h because it is not C99
+   compliant.  See compiler macros and version number in
+   https://sourceforge.net/p/predef/wiki/Compilers/ */
+#  include <stdint.h>
+#else /* !defined(_MSC_VER) || (_MSC_VER >= 1800) */
+#  include <inttypes.h>
+#endif /* !defined(_MSC_VER) || (_MSC_VER >= 1800) */
+#include <sys/types.h>
+#include <stdarg.h>
+#include <stddef.h>
+
+#include <nghttp3/version.h>
+
+#ifdef NGHTTP3_STATICLIB
+#  define NGHTTP3_EXTERN
+#elif defined(WIN32)
+#  ifdef BUILDING_NGHTTP3
+#    define NGHTTP3_EXTERN __declspec(dllexport)
+#  else /* !BUILDING_NGHTTP3 */
+#    define NGHTTP3_EXTERN __declspec(dllimport)
+#  endif /* !BUILDING_NGHTTP3 */
+#else    /* !defined(WIN32) */
+#  ifdef BUILDING_NGHTTP3
+#    define NGHTTP3_EXTERN __attribute__((visibility("default")))
+#  else /* !BUILDING_NGHTTP3 */
+#    define NGHTTP3_EXTERN
+#  endif /* !BUILDING_NGHTTP3 */
+#endif   /* !defined(WIN32) */
+
+/**
+ * @typedef
+ *
+ * :type:`nghttp3_ssize` is signed counterpart of size_t.
+ */
+typedef ptrdiff_t nghttp3_ssize;
+
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_ALPN_H3` is a serialized form of HTTP/3 ALPN
+ * protocol identifier this library supports.  Notice that the first
+ * byte is the length of the following protocol identifier.
+ */
+#define NGHTTP3_ALPN_H3 "\x2h3"
+
+/**
+ * @macrosection
+ *
+ * nghttp3 library error codes
+ */
+
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_ERR_INVALID_ARGUMENT` indicates that a passed
+ * argument is invalid.
+ */
+#define NGHTTP3_ERR_INVALID_ARGUMENT -101
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_ERR_NOBUF` indicates that a provided buffer does
+ * not have enough space to store data.
+ */
+#define NGHTTP3_ERR_NOBUF -102
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_ERR_INVALID_STATE` indicates that a requested
+ * operation is not allowed at the current connection state.
+ */
+#define NGHTTP3_ERR_INVALID_STATE -103
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_ERR_WOULDBLOCK` indicates that an operation might
+ * block.
+ */
+#define NGHTTP3_ERR_WOULDBLOCK -104
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_ERR_STREAM_IN_USE` indicates that a stream ID is
+ * already in use.
+ */
+#define NGHTTP3_ERR_STREAM_IN_USE -105
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_ERR_MALFORMED_HTTP_HEADER` indicates that an HTTP
+ * header field is malformed.
+ */
+#define NGHTTP3_ERR_MALFORMED_HTTP_HEADER -107
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_ERR_REMOVE_HTTP_HEADER` indicates that an HTTP
+ * header field is discarded.
+ */
+#define NGHTTP3_ERR_REMOVE_HTTP_HEADER -108
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_ERR_MALFORMED_HTTP_MESSAGING` indicates that HTTP
+ * messaging is malformed.
+ */
+#define NGHTTP3_ERR_MALFORMED_HTTP_MESSAGING -109
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_ERR_QPACK_FATAL` indicates that a fatal error is
+ * occurred during QPACK processing and it cannot be recoverable.
+ */
+#define NGHTTP3_ERR_QPACK_FATAL -111
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_ERR_QPACK_HEADER_TOO_LARGE` indicates that a header
+ * field is too large to process.
+ */
+#define NGHTTP3_ERR_QPACK_HEADER_TOO_LARGE -112
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_ERR_STREAM_NOT_FOUND` indicates that a stream is
+ * not found.
+ */
+#define NGHTTP3_ERR_STREAM_NOT_FOUND -114
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_ERR_CONN_CLOSING` indicates that a connection is
+ * closing state.
+ */
+#define NGHTTP3_ERR_CONN_CLOSING -116
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_ERR_STREAM_DATA_OVERFLOW` indicates that the length
+ * of stream data is too long and causes overflow.
+ */
+#define NGHTTP3_ERR_STREAM_DATA_OVERFLOW -117
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_ERR_QPACK_DECOMPRESSION_FAILED` indicates that a
+ * QPACK decompression failed.
+ */
+#define NGHTTP3_ERR_QPACK_DECOMPRESSION_FAILED -402
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_ERR_QPACK_ENCODER_STREAM_ERROR` indicates that an
+ * error occurred while reading QPACK encoder stream.
+ */
+#define NGHTTP3_ERR_QPACK_ENCODER_STREAM_ERROR -403
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_ERR_QPACK_DECODER_STREAM_ERROR` indicates that an
+ * error occurred while reading QPACK decoder stream.
+ */
+#define NGHTTP3_ERR_QPACK_DECODER_STREAM_ERROR -404
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_ERR_H3_FRAME_UNEXPECTED` indicates that an
+ * unexpected HTTP/3 frame is received.
+ */
+#define NGHTTP3_ERR_H3_FRAME_UNEXPECTED -408
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_ERR_H3_FRAME_ERROR` indicates that an HTTP/3 frame
+ * is malformed.
+ */
+#define NGHTTP3_ERR_H3_FRAME_ERROR -409
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_ERR_H3_MISSING_SETTINGS` indicates that an HTTP/3
+ * SETTINGS frame is missing.
+ */
+#define NGHTTP3_ERR_H3_MISSING_SETTINGS -665
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_ERR_H3_INTERNAL_ERROR` indicates an internal error.
+ */
+#define NGHTTP3_ERR_H3_INTERNAL_ERROR -667
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_ERR_H3_CLOSED_CRITICAL_STREAM` indicates that a
+ * critical stream is closed.
+ */
+#define NGHTTP3_ERR_H3_CLOSED_CRITICAL_STREAM -668
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_ERR_H3_GENERAL_PROTOCOL_ERROR` indicates a general
+ * protocol error.  This is typically a catch-all error.
+ */
+#define NGHTTP3_ERR_H3_GENERAL_PROTOCOL_ERROR -669
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_ERR_H3_ID_ERROR` indicates that an ID related error
+ * occurred.
+ */
+#define NGHTTP3_ERR_H3_ID_ERROR -670
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_ERR_H3_SETTINGS_ERROR` indicates that an HTTP/3
+ * SETTINGS frame is malformed.
+ */
+#define NGHTTP3_ERR_H3_SETTINGS_ERROR -671
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_ERR_H3_STREAM_CREATION_ERROR` indicates that a
+ * remote endpoint attempts to create a new stream which is not
+ * allowed.
+ */
+#define NGHTTP3_ERR_H3_STREAM_CREATION_ERROR -672
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_ERR_FATAL` indicates that error codes less than
+ * this value is fatal error.  When this error is returned, an
+ * endpoint should drop connection immediately.
+ */
+#define NGHTTP3_ERR_FATAL -900
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_ERR_NOMEM` indicates out of memory.
+ */
+#define NGHTTP3_ERR_NOMEM -901
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_ERR_CALLBACK_FAILURE` indicates that user defined
+ * callback function failed.
+ */
+#define NGHTTP3_ERR_CALLBACK_FAILURE -902
+
+/**
+ * @macrosection
+ *
+ * HTTP/3 application error code
+ */
+
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_H3_NO_ERROR` is HTTP/3 application error code
+ * ``H3_NO_ERROR``.
+ */
+#define NGHTTP3_H3_NO_ERROR 0x0100
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_H3_GENERAL_PROTOCOL_ERROR` is HTTP/3 application
+ * error code ``H3_GENERAL_PROTOCOL_ERROR``.
+ */
+#define NGHTTP3_H3_GENERAL_PROTOCOL_ERROR 0x0101
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_H3_INTERNAL_ERROR` is HTTP/3 application error code
+ * ``H3_INTERNAL_ERROR``.
+ */
+#define NGHTTP3_H3_INTERNAL_ERROR 0x0102
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_H3_STREAM_CREATION_ERROR` is HTTP/3 application
+ * error code ``H3_STREAM_CREATION_ERROR``.
+ */
+#define NGHTTP3_H3_STREAM_CREATION_ERROR 0x0103
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_H3_CLOSED_CRITICAL_STREAM` is HTTP/3 application
+ * error code ``H3_CLOSED_CRITICAL_STREAM``.
+ */
+#define NGHTTP3_H3_CLOSED_CRITICAL_STREAM 0x0104
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_H3_FRAME_UNEXPECTED` is HTTP/3 application error
+ * code ``H3_FRAME_UNEXPECTED``.
+ */
+#define NGHTTP3_H3_FRAME_UNEXPECTED 0x0105
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_H3_FRAME_ERROR` is HTTP/3 application error code
+ * ``H3_FRAME_ERROR``.
+ */
+#define NGHTTP3_H3_FRAME_ERROR 0x0106
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_H3_EXCESSIVE_LOAD` is HTTP/3 application error code
+ * ``H3_EXCESSIVE_LOAD``.
+ */
+#define NGHTTP3_H3_EXCESSIVE_LOAD 0x0107
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_H3_ID_ERROR` is HTTP/3 application error code
+ * ``H3_ID_ERROR``.
+ */
+#define NGHTTP3_H3_ID_ERROR 0x0108
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_H3_SETTINGS_ERROR` is HTTP/3 application error code
+ * ``H3_SETTINGS_ERROR``.
+ */
+#define NGHTTP3_H3_SETTINGS_ERROR 0x0109
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_H3_MISSING_SETTINGS` is HTTP/3 application error
+ * code ``H3_MISSING_SETTINGS``.
+ */
+#define NGHTTP3_H3_MISSING_SETTINGS 0x010a
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_H3_REQUEST_REJECTED` is HTTP/3 application error
+ * code ``H3_REQUEST_REJECTED``.
+ */
+#define NGHTTP3_H3_REQUEST_REJECTED 0x010b
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_H3_REQUEST_CANCELLED` is HTTP/3 application error
+ * code ``H3_REQUEST_CANCELLED``.
+ */
+#define NGHTTP3_H3_REQUEST_CANCELLED 0x010c
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_H3_REQUEST_INCOMPLETE` is HTTP/3 application error
+ * code ``H3_REQUEST_INCOMPLETE``.
+ */
+#define NGHTTP3_H3_REQUEST_INCOMPLETE 0x010d
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_H3_MESSAGE_ERROR` is HTTP/3 application error code
+ * ``H3_MESSAGE_ERROR``.
+ */
+#define NGHTTP3_H3_MESSAGE_ERROR 0x010e
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_H3_CONNECT_ERROR` is HTTP/3 application error code
+ * ``H3_CONNECT_ERROR``.
+ */
+#define NGHTTP3_H3_CONNECT_ERROR 0x010f
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_H3_VERSION_FALLBACK` is HTTP/3 application error
+ * code ``H3_VERSION_FALLBACK``.
+ */
+#define NGHTTP3_H3_VERSION_FALLBACK 0x0110
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_QPACK_DECOMPRESSION_FAILED` is HTTP/3 application
+ * error code ``QPACK_DECOMPRESSION_FAILED``.
+ */
+#define NGHTTP3_QPACK_DECOMPRESSION_FAILED 0x0200
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_QPACK_ENCODER_STREAM_ERROR` is HTTP/3 application
+ * error code ``QPACK_ENCODER_STREAM_ERROR``.
+ */
+#define NGHTTP3_QPACK_ENCODER_STREAM_ERROR 0x0201
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_QPACK_DECODER_STREAM_ERROR` is HTTP/3 application
+ * error code ``QPACK_DECODER_STREAM_ERROR``.
+ */
+#define NGHTTP3_QPACK_DECODER_STREAM_ERROR 0x0202
+
+/**
+ * @functypedef
+ *
+ * :type:`nghttp3_malloc` is a custom memory allocator to replace
+ * :manpage:`malloc(3)`.  The |user_data| is the
+ * :member:`nghttp3_mem.user_data`.
+ */
+typedef void *(*nghttp3_malloc)(size_t size, void *user_data);
+
+/**
+ * @functypedef
+ *
+ * :type:`nghttp3_free` is a custom memory allocator to replace
+ * :manpage:`free(3)`.  The |user_data| is the
+ * :member:`nghttp3_mem.user_data`.
+ */
+typedef void (*nghttp3_free)(void *ptr, void *user_data);
+
+/**
+ * @functypedef
+ *
+ * :type:`nghttp3_calloc` is a custom memory allocator to replace
+ * :manpage:`calloc(3)`.  The |user_data| is the
+ * :member:`nghttp3_mem.user_data`.
+ */
+typedef void *(*nghttp3_calloc)(size_t nmemb, size_t size, void *user_data);
+
+/**
+ * @functypedef
+ *
+ * :type:`nghttp3_realloc` is a custom memory allocator to replace
+ * :manpage:`realloc(3)`.  The |user_data| is the
+ * :member:`nghttp3_mem.user_data`.
+ */
+typedef void *(*nghttp3_realloc)(void *ptr, size_t size, void *user_data);
+
+/**
+ * @struct
+ *
+ * :type:`nghttp3_mem` is a custom memory allocator functions and user
+ * defined pointer.  The :member:`user_data` field is passed to each
+ * allocator function.  This can be used, for example, to achieve
+ * per-session memory pool.
+ *
+ * In the following example code, ``my_malloc``, ``my_free``,
+ * ``my_calloc`` and ``my_realloc`` are the replacement of the
+ * standard allocators :manpage:`malloc(3)`, :manpage:`free(3)`,
+ * :manpage:`calloc(3)` and :manpage:`realloc(3)` respectively::
+ *
+ *     void *my_malloc_cb(size_t size, void *user_data) {
+ *       (void)user_data;
+ *       return my_malloc(size);
+ *     }
+ *
+ *     void my_free_cb(void *ptr, void *user_data) {
+ *       (void)user_data;
+ *       my_free(ptr);
+ *     }
+ *
+ *     void *my_calloc_cb(size_t nmemb, size_t size, void *user_data) {
+ *       (void)user_data;
+ *       return my_calloc(nmemb, size);
+ *     }
+ *
+ *     void *my_realloc_cb(void *ptr, size_t size, void *user_data) {
+ *       (void)user_data;
+ *       return my_realloc(ptr, size);
+ *     }
+ *
+ *     void conn_new() {
+ *       nghttp3_mem mem = {NULL, my_malloc_cb, my_free_cb, my_calloc_cb,
+ *                          my_realloc_cb};
+ *
+ *       ...
+ *     }
+ */
+typedef struct nghttp3_mem {
+  /**
+   * :member:`user_data` is an arbitrary user supplied data.  This
+   * is passed to each allocator function.
+   */
+  void *user_data;
+  /**
+   * :member:`malloc` is a custom allocator function to replace
+   * :manpage:`malloc(3)`.
+   */
+  nghttp3_malloc malloc;
+  /**
+   * :member:`free` is a custom allocator function to replace
+   * :manpage:`free(3)`.
+   */
+  nghttp3_free free;
+  /**
+   * :member:`calloc` is a custom allocator function to replace
+   * :manpage:`calloc(3)`.
+   */
+  nghttp3_calloc calloc;
+  /**
+   * :member:`realloc` is a custom allocator function to replace
+   * :manpage:`realloc(3)`.
+   */
+  nghttp3_realloc realloc;
+} nghttp3_mem;
+
+/**
+ * @function
+ *
+ * `nghttp3_mem_default` returns the default memory allocator which
+ * uses malloc/calloc/realloc/free.
+ */
+NGHTTP3_EXTERN const nghttp3_mem *nghttp3_mem_default(void);
+
+/**
+ * @struct
+ *
+ * :type:`nghttp3_vec` is ``struct iovec`` compatible structure to
+ * reference arbitrary array of bytes.
+ */
+typedef struct nghttp3_vec {
+  /**
+   * :member:`base` points to the data.
+   */
+  uint8_t *base;
+  /**
+   * :member:`len` is the number of bytes which the buffer pointed by
+   * base contains.
+   */
+  size_t len;
+} nghttp3_vec;
+
+/**
+ * @struct
+ *
+ * :type:`nghttp3_rcbuf` is the object representing reference counted
+ * buffer.  The details of this structure are intentionally hidden
+ * from the public API.
+ */
+typedef struct nghttp3_rcbuf nghttp3_rcbuf;
+
+/**
+ * @function
+ *
+ * `nghttp3_rcbuf_incref` increments the reference count of |rcbuf| by
+ * 1.
+ */
+NGHTTP3_EXTERN void nghttp3_rcbuf_incref(nghttp3_rcbuf *rcbuf);
+
+/**
+ * @function
+ *
+ * `nghttp3_rcbuf_decref` decrements the reference count of |rcbuf| by
+ * 1.  If the reference count becomes zero, the object pointed by
+ * |rcbuf| will be freed.  In this case, application must not use
+ * |rcbuf| again.
+ */
+NGHTTP3_EXTERN void nghttp3_rcbuf_decref(nghttp3_rcbuf *rcbuf);
+
+/**
+ * @function
+ *
+ * `nghttp3_rcbuf_get_buf` returns the underlying buffer managed by
+ * |rcbuf|.
+ */
+NGHTTP3_EXTERN nghttp3_vec nghttp3_rcbuf_get_buf(const nghttp3_rcbuf *rcbuf);
+
+/**
+ * @function
+ *
+ * `nghttp3_rcbuf_is_static` returns nonzero if the underlying buffer
+ * is statically allocated, and 0 otherwise. This can be useful for
+ * language bindings that wish to avoid creating duplicate strings for
+ * these buffers.
+ */
+NGHTTP3_EXTERN int nghttp3_rcbuf_is_static(const nghttp3_rcbuf *rcbuf);
+
+/**
+ * @struct
+ *
+ * :type:`nghttp3_buf` is the variable size buffer.
+ */
+typedef struct nghttp3_buf {
+  /**
+   * :member:`begin` points to the beginning of the buffer.
+   */
+  uint8_t *begin;
+  /**
+   * :member:`end` points to the one beyond of the last byte of the
+   * buffer
+   */
+  uint8_t *end;
+  /**
+   * :member:`pos` pointers to the start of data.  Typically, this
+   * points to the point that next data should be read.  Initially, it
+   * points to :member:`begin`.
+   */
+  uint8_t *pos;
+  /**
+   * :member:`last` points to the one beyond of the last data of the
+   * buffer.  Typically, new data is written at this point.
+   * Initially, it points to :member:`begin`.
+   */
+  uint8_t *last;
+} nghttp3_buf;
+
+/**
+ * @function
+ *
+ * `nghttp3_buf_init` initializes empty |buf|.
+ */
+NGHTTP3_EXTERN void nghttp3_buf_init(nghttp3_buf *buf);
+
+/**
+ * @function
+ *
+ * `nghttp3_buf_free` frees resources allocated for |buf| using |mem|
+ * as memory allocator.  :member:`buf->begin <nghttp3_buf.begin>` must
+ * be a heap buffer allocated by |mem|.
+ */
+NGHTTP3_EXTERN void nghttp3_buf_free(nghttp3_buf *buf, const nghttp3_mem *mem);
+
+/**
+ * @function
+ *
+ * `nghttp3_buf_left` returns the number of additional bytes which can
+ * be written to the underlying buffer.  In other words, it returns
+ * :member:`buf->end <nghttp3_buf.end>` - :member:`buf->last
+ * <nghttp3_buf.last>`.
+ */
+NGHTTP3_EXTERN size_t nghttp3_buf_left(const nghttp3_buf *buf);
+
+/**
+ * @function
+ *
+ * `nghttp3_buf_len` returns the number of bytes left to read.  In
+ * other words, it returns :member:`buf->last <nghttp3_buf.last>` -
+ * :member:`buf->pos <nghttp3_buf.pos>`.
+ */
+NGHTTP3_EXTERN size_t nghttp3_buf_len(const nghttp3_buf *buf);
+
+/**
+ * @function
+ *
+ * `nghttp3_buf_reset` sets :member:`buf->pos <nghttp3_buf.pos>` and
+ * :member:`buf->last <nghttp3_buf.last>` to :member:`buf->begin
+ * <nghttp3_buf.begin>`.
+ */
+NGHTTP3_EXTERN void nghttp3_buf_reset(nghttp3_buf *buf);
+
+/**
+ * @macrosection
+ *
+ * Flags for header field name/value pair
+ */
+
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_NV_FLAG_NONE` indicates no flag set.
+ */
+#define NGHTTP3_NV_FLAG_NONE 0x00u
+
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_NV_FLAG_NEVER_INDEX` indicates that this name/value
+ * pair must not be indexed.  Other implementation calls this bit as
+ * "sensitive".
+ */
+#define NGHTTP3_NV_FLAG_NEVER_INDEX 0x01u
+
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_NV_FLAG_NO_COPY_NAME` is set solely by application.
+ * If this flag is set, the library does not make a copy of header
+ * field name.  This could improve performance.
+ */
+#define NGHTTP3_NV_FLAG_NO_COPY_NAME 0x02u
+
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_NV_FLAG_NO_COPY_VALUE` is set solely by
+ * application.  If this flag is set, the library does not make a copy
+ * of header field value.  This could improve performance.
+ */
+#define NGHTTP3_NV_FLAG_NO_COPY_VALUE 0x04u
+
+/**
+ * @struct
+ *
+ * :type:`nghttp3_nv` is the name/value pair, which mainly used to
+ * represent header fields.
+ */
+typedef struct nghttp3_nv {
+  /**
+   * :member:`name` is the header field name.
+   */
+  uint8_t *name;
+  /**
+   * :member:`value` is the header field value.
+   */
+  uint8_t *value;
+  /**
+   * :member:`namelen` is the length of the |name|, excluding
+   * terminating NULL.
+   */
+  size_t namelen;
+  /**
+   * :member:`valuelen` is the length of the |value|, excluding
+   * terminating NULL.
+   */
+  size_t valuelen;
+  /**
+   * :member:`flags` is bitwise OR of one or more of
+   * :macro:`NGHTTP3_NV_FLAG_* <NGHTTP3_NV_FLAG_NONE>`.
+   */
+  uint8_t flags;
+} nghttp3_nv;
+
+/* Generated by mkstatichdtbl.py */
+/**
+ * @enum
+ *
+ * :type:`nghttp3_qpack_token` defines HTTP header field name tokens
+ * to identify field name quickly.  It appears in
+ * :member:`nghttp3_qpack_nv.token`.
+ */
+typedef enum nghttp3_qpack_token {
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN__AUTHORITY` is a token for
+   * ``:authority``.
+   */
+  NGHTTP3_QPACK_TOKEN__AUTHORITY = 0,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN__PATH` is a token for ``:path``.
+   */
+  NGHTTP3_QPACK_TOKEN__PATH = 8,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_AGE` is a token for ``age``.
+   */
+  NGHTTP3_QPACK_TOKEN_AGE = 43,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_CONTENT_DISPOSITION` is a token for
+   * ``content-disposition``.
+   */
+  NGHTTP3_QPACK_TOKEN_CONTENT_DISPOSITION = 52,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_CONTENT_LENGTH` is a token for
+   * ``content-length``.
+   */
+  NGHTTP3_QPACK_TOKEN_CONTENT_LENGTH = 55,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_COOKIE` is a token for ``cookie``.
+   */
+  NGHTTP3_QPACK_TOKEN_COOKIE = 68,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_DATE` is a token for ``date``.
+   */
+  NGHTTP3_QPACK_TOKEN_DATE = 69,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_ETAG` is a token for ``etag``.
+   */
+  NGHTTP3_QPACK_TOKEN_ETAG = 71,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_IF_MODIFIED_SINCE` is a token for
+   * ``if-modified-since``.
+   */
+  NGHTTP3_QPACK_TOKEN_IF_MODIFIED_SINCE = 74,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_IF_NONE_MATCH` is a token for
+   * ``if-none-match``.
+   */
+  NGHTTP3_QPACK_TOKEN_IF_NONE_MATCH = 75,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_LAST_MODIFIED` is a token for
+   * ``last-modified``.
+   */
+  NGHTTP3_QPACK_TOKEN_LAST_MODIFIED = 77,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_LINK` is a token for ``link``.
+   */
+  NGHTTP3_QPACK_TOKEN_LINK = 78,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_LOCATION` is a token for ``location``.
+   */
+  NGHTTP3_QPACK_TOKEN_LOCATION = 79,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_REFERER` is a token for ``referer``.
+   */
+  NGHTTP3_QPACK_TOKEN_REFERER = 83,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_SET_COOKIE` is a token for
+   * ``set-cookie``.
+   */
+  NGHTTP3_QPACK_TOKEN_SET_COOKIE = 85,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN__METHOD` is a token for ``:method``.
+   */
+  NGHTTP3_QPACK_TOKEN__METHOD = 1,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN__SCHEME` is a token for ``:scheme``.
+   */
+  NGHTTP3_QPACK_TOKEN__SCHEME = 9,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN__STATUS` is a token for ``:status``.
+   */
+  NGHTTP3_QPACK_TOKEN__STATUS = 11,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_ACCEPT` is a token for ``accept``.
+   */
+  NGHTTP3_QPACK_TOKEN_ACCEPT = 25,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_ACCEPT_ENCODING` is a token for
+   * ``accept-encoding``.
+   */
+  NGHTTP3_QPACK_TOKEN_ACCEPT_ENCODING = 27,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_ACCEPT_RANGES` is a token for
+   * ``accept-ranges``.
+   */
+  NGHTTP3_QPACK_TOKEN_ACCEPT_RANGES = 29,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_ACCESS_CONTROL_ALLOW_HEADERS` is a
+   * token for ``access-control-allow-headers``.
+   */
+  NGHTTP3_QPACK_TOKEN_ACCESS_CONTROL_ALLOW_HEADERS = 32,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_ACCESS_CONTROL_ALLOW_ORIGIN` is a
+   * token for ``access-control-allow-origin``.
+   */
+  NGHTTP3_QPACK_TOKEN_ACCESS_CONTROL_ALLOW_ORIGIN = 38,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_CACHE_CONTROL` is a token for
+   * ``cache-control``.
+   */
+  NGHTTP3_QPACK_TOKEN_CACHE_CONTROL = 46,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_CONTENT_ENCODING` is a token for
+   * ``content-encoding``.
+   */
+  NGHTTP3_QPACK_TOKEN_CONTENT_ENCODING = 53,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_CONTENT_TYPE` is a token for
+   * ``content-type``.
+   */
+  NGHTTP3_QPACK_TOKEN_CONTENT_TYPE = 57,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_RANGE` is a token for ``range``.
+   */
+  NGHTTP3_QPACK_TOKEN_RANGE = 82,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_STRICT_TRANSPORT_SECURITY` is a token
+   * for ``strict-transport-security``.
+   */
+  NGHTTP3_QPACK_TOKEN_STRICT_TRANSPORT_SECURITY = 86,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_VARY` is a token for ``vary``.
+   */
+  NGHTTP3_QPACK_TOKEN_VARY = 92,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_X_CONTENT_TYPE_OPTIONS` is a token for
+   * ``x-content-type-options``.
+   */
+  NGHTTP3_QPACK_TOKEN_X_CONTENT_TYPE_OPTIONS = 94,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_X_XSS_PROTECTION` is a token for
+   * ``x-xss-protection``.
+   */
+  NGHTTP3_QPACK_TOKEN_X_XSS_PROTECTION = 98,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_ACCEPT_LANGUAGE` is a token for
+   * ``accept-language``.
+   */
+  NGHTTP3_QPACK_TOKEN_ACCEPT_LANGUAGE = 28,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_ACCESS_CONTROL_ALLOW_CREDENTIALS` is a
+   * token for ``access-control-allow-credentials``.
+   */
+  NGHTTP3_QPACK_TOKEN_ACCESS_CONTROL_ALLOW_CREDENTIALS = 30,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_ACCESS_CONTROL_ALLOW_METHODS` is a
+   * token for ``access-control-allow-methods``.
+   */
+  NGHTTP3_QPACK_TOKEN_ACCESS_CONTROL_ALLOW_METHODS = 35,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_ACCESS_CONTROL_EXPOSE_HEADERS` is a
+   * token for ``access-control-expose-headers``.
+   */
+  NGHTTP3_QPACK_TOKEN_ACCESS_CONTROL_EXPOSE_HEADERS = 39,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_ACCESS_CONTROL_REQUEST_HEADERS` is a
+   * token for ``access-control-request-headers``.
+   */
+  NGHTTP3_QPACK_TOKEN_ACCESS_CONTROL_REQUEST_HEADERS = 40,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_ACCESS_CONTROL_REQUEST_METHOD` is a
+   * token for ``access-control-request-method``.
+   */
+  NGHTTP3_QPACK_TOKEN_ACCESS_CONTROL_REQUEST_METHOD = 41,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_ALT_SVC` is a token for ``alt-svc``.
+   */
+  NGHTTP3_QPACK_TOKEN_ALT_SVC = 44,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_AUTHORIZATION` is a token for
+   * ``authorization``.
+   */
+  NGHTTP3_QPACK_TOKEN_AUTHORIZATION = 45,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_CONTENT_SECURITY_POLICY` is a token
+   * for ``content-security-policy``.
+   */
+  NGHTTP3_QPACK_TOKEN_CONTENT_SECURITY_POLICY = 56,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_EARLY_DATA` is a token for
+   * ``early-data``.
+   */
+  NGHTTP3_QPACK_TOKEN_EARLY_DATA = 70,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_EXPECT_CT` is a token for
+   * ``expect-ct``.
+   */
+  NGHTTP3_QPACK_TOKEN_EXPECT_CT = 72,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_FORWARDED` is a token for
+   * ``forwarded``.
+   */
+  NGHTTP3_QPACK_TOKEN_FORWARDED = 73,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_IF_RANGE` is a token for ``if-range``.
+   */
+  NGHTTP3_QPACK_TOKEN_IF_RANGE = 76,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_ORIGIN` is a token for ``origin``.
+   */
+  NGHTTP3_QPACK_TOKEN_ORIGIN = 80,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_PURPOSE` is a token for ``purpose``.
+   */
+  NGHTTP3_QPACK_TOKEN_PURPOSE = 81,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_SERVER` is a token for ``server``.
+   */
+  NGHTTP3_QPACK_TOKEN_SERVER = 84,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_TIMING_ALLOW_ORIGIN` is a token for
+   * ``timing-allow-origin``.
+   */
+  NGHTTP3_QPACK_TOKEN_TIMING_ALLOW_ORIGIN = 89,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_UPGRADE_INSECURE_REQUESTS` is a token
+   * for ``upgrade-insecure-requests``.
+   */
+  NGHTTP3_QPACK_TOKEN_UPGRADE_INSECURE_REQUESTS = 90,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_USER_AGENT` is a token for
+   * ``user-agent``.
+   */
+  NGHTTP3_QPACK_TOKEN_USER_AGENT = 91,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_X_FORWARDED_FOR` is a token for
+   * ``x-forwarded-for``.
+   */
+  NGHTTP3_QPACK_TOKEN_X_FORWARDED_FOR = 95,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_X_FRAME_OPTIONS` is a token for
+   * ``x-frame-options``.
+   */
+  NGHTTP3_QPACK_TOKEN_X_FRAME_OPTIONS = 96,
+
+  /* Additional header fields for HTTP messaging validation */
+
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_HOST` is a token for ``host``.
+   */
+  NGHTTP3_QPACK_TOKEN_HOST = 1000,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_CONNECTION` is a token for
+   * ``connection``.
+   */
+  NGHTTP3_QPACK_TOKEN_CONNECTION,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_KEEP_ALIVE` is a token for
+   * ``keep-alive``.
+   */
+  NGHTTP3_QPACK_TOKEN_KEEP_ALIVE,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_PROXY_CONNECTION` is a token for
+   * ``proxy-connection``.
+   */
+  NGHTTP3_QPACK_TOKEN_PROXY_CONNECTION,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_TRANSFER_ENCODING` is a token for
+   * ``transfer-encoding``.
+   */
+  NGHTTP3_QPACK_TOKEN_TRANSFER_ENCODING,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_UPGRADE` is a token for ``upgrade``.
+   */
+  NGHTTP3_QPACK_TOKEN_UPGRADE,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_TE` is a token for ``te``.
+   */
+  NGHTTP3_QPACK_TOKEN_TE,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN__PROTOCOL` is a token for
+   * ``:protocol``.
+   */
+  NGHTTP3_QPACK_TOKEN__PROTOCOL,
+  /**
+   * :enum:`NGHTTP3_QPACK_TOKEN_PRIORITY` is a token for ``priority``.
+   */
+  NGHTTP3_QPACK_TOKEN_PRIORITY
+} nghttp3_qpack_token;
+
+/**
+ * @struct
+ *
+ * :type:`nghttp3_qpack_nv` represents header field name/value pair
+ * just like :type:`nghttp3_nv`.  It is an extended version of
+ * :type:`nghttp3_nv` and has reference counted buffers and tokens
+ * which might be useful for applications.
+ */
+typedef struct nghttp3_qpack_nv {
+  /**
+   * :member:`name` is the buffer containing header field name.
+   * NULL-termination is guaranteed.
+   */
+  nghttp3_rcbuf *name;
+  /**
+   * :member:`value` is the buffer containing header field value.
+   * NULL-termination is guaranteed.
+   */
+  nghttp3_rcbuf *value;
+  /**
+   * :member:`token` is :type:`nghttp3_qpack_token` value of
+   *  :member:`name`.  It could be -1 if we have no token for that
+   *  header field name.
+   */
+  int32_t token;
+  /**
+   * :member:`flags` is a bitwise OR of one or more of
+   * :macro:`NGHTTP3_NV_FLAG_* <NGHTTP3_NV_FLAG_NONE>`.
+   */
+  uint8_t flags;
+} nghttp3_qpack_nv;
+
+/**
+ * @struct
+ *
+ * :type:`nghttp3_qpack_encoder` is QPACK encoder.
+ */
+typedef struct nghttp3_qpack_encoder nghttp3_qpack_encoder;
+
+/**
+ * @function
+ *
+ * `nghttp3_qpack_encoder_new` initializes QPACK encoder.  |pencoder|
+ * must be non-NULL pointer.  |hard_max_dtable_capacity| is the upper
+ * bound of the dynamic table capacity.  |mem| is a memory allocator.
+ * This function allocates memory for :type:`nghttp3_qpack_encoder`
+ * itself and assigns its pointer to |*pencoder| if it succeeds.
+ *
+ * The maximum dynamic table capacity is still 0.  In order to change
+ * the maximum dynamic table capacity, call
+ * `nghttp3_qpack_encoder_set_max_dtable_capacity`.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * :macro:`NGHTTP3_ERR_NOMEM`
+ *     Out of memory.
+ */
+NGHTTP3_EXTERN int nghttp3_qpack_encoder_new(nghttp3_qpack_encoder **pencoder,
+                                             size_t hard_max_dtable_capacity,
+                                             const nghttp3_mem *mem);
+
+/**
+ * @function
+ *
+ * `nghttp3_qpack_encoder_del` frees memory allocated for |encoder|.
+ * This function frees memory pointed by |encoder| itself.
+ */
+NGHTTP3_EXTERN void nghttp3_qpack_encoder_del(nghttp3_qpack_encoder *encoder);
+
+/**
+ * @function
+ *
+ * `nghttp3_qpack_encoder_encode` encodes the list of header fields
+ * |nva|.  |nvlen| is the length of |nva|.  |stream_id| is the
+ * identifier of the stream which this header fields belong to.  This
+ * function writes header block prefix, encoded header fields, and
+ * encoder stream to |pbuf|, |rbuf|, and |ebuf| respectively.  The
+ * :member:`nghttp3_buf.last` will be adjusted when data is written.
+ * An application should write |pbuf| and |rbuf| to the request stream
+ * in this order.
+ *
+ * The buffer pointed by |pbuf|, |rbuf|, and |ebuf| can be empty
+ * buffer.  It is fine to pass a buffer initialized by
+ * `nghttp3_buf_init(buf) <nghttp3_buf_init>`.  This function
+ * allocates memory for these buffers as necessary.  In particular, it
+ * frees and expands buffer if the current capacity of buffer is not
+ * enough.  If :member:`nghttp3_buf.begin` of any buffer is not NULL,
+ * it must be allocated by the same memory allocator passed to
+ * `nghttp3_qpack_encoder_new()`.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * :macro:`NGHTTP3_ERR_NOMEM`
+ *     Out of memory
+ * :macro:`NGHTTP3_ERR_QPACK_FATAL`
+ *      |encoder| is in unrecoverable error state and cannot be used
+ *      anymore.
+ */
+NGHTTP3_EXTERN int nghttp3_qpack_encoder_encode(
+    nghttp3_qpack_encoder *encoder, nghttp3_buf *pbuf, nghttp3_buf *rbuf,
+    nghttp3_buf *ebuf, int64_t stream_id, const nghttp3_nv *nva, size_t nvlen);
+
+/**
+ * @function
+ *
+ * `nghttp3_qpack_encoder_read_decoder` reads decoder stream.  The
+ * buffer pointed by |src| of length |srclen| contains decoder stream.
+ *
+ * This function returns the number of bytes read, or one of the
+ * following negative error codes:
+ *
+ * :macro:`NGHTTP3_ERR_NOMEM`
+ *     Out of memory
+ * :macro:`NGHTTP3_ERR_QPACK_FATAL`
+ *     |encoder| is in unrecoverable error state and cannot be used
+ *     anymore.
+ * :macro:`NGHTTP3_ERR_QPACK_DECODER_STREAM`
+ *     |encoder| is unable to process input because it is malformed.
+ */
+NGHTTP3_EXTERN nghttp3_ssize nghttp3_qpack_encoder_read_decoder(
+    nghttp3_qpack_encoder *encoder, const uint8_t *src, size_t srclen);
+
+/**
+ * @function
+ *
+ * `nghttp3_qpack_encoder_set_max_dtable_capacity` sets max dynamic
+ * table capacity to |max_dtable_capacity|.  If |max_dtable_capacity| is
+ * larger than ``hard_max_dtable_capacity`` parameter of
+ * `nghttp3_qpack_encoder_new`, it is truncated to the latter.
+ */
+NGHTTP3_EXTERN void
+nghttp3_qpack_encoder_set_max_dtable_capacity(nghttp3_qpack_encoder *encoder,
+                                              size_t max_dtable_capacity);
+
+/**
+ * @function
+ *
+ * `nghttp3_qpack_encoder_set_max_blocked_streams` sets the number of
+ * streams which can be blocked to |max_blocked_streams|.
+ */
+NGHTTP3_EXTERN void
+nghttp3_qpack_encoder_set_max_blocked_streams(nghttp3_qpack_encoder *encoder,
+                                              size_t max_blocked_streams);
+
+/**
+ * @function
+ *
+ * `nghttp3_qpack_encoder_ack_everything` tells |encoder| that all
+ * encoded header blocks are acknowledged.  This function is provided
+ * for debugging purpose only.  In HTTP/3, |encoder| knows this by
+ * reading decoder stream with `nghttp3_qpack_encoder_read_decoder()`.
+ */
+NGHTTP3_EXTERN void
+nghttp3_qpack_encoder_ack_everything(nghttp3_qpack_encoder *encoder);
+
+/**
+ * @function
+ *
+ * `nghttp3_qpack_encoder_get_num_blocked_streams` returns the number
+ * of streams which are potentially blocked at decoder side.
+ */
+NGHTTP3_EXTERN size_t
+nghttp3_qpack_encoder_get_num_blocked_streams(nghttp3_qpack_encoder *encoder);
+
+/**
+ * @struct
+ *
+ * :type:`nghttp3_qpack_stream_context` is a decoder context for an
+ * individual stream.  Its state is per header block.  In order to
+ * reuse this object for another header block, call
+ * `nghttp3_qpack_stream_context_reset`.
+ */
+typedef struct nghttp3_qpack_stream_context nghttp3_qpack_stream_context;
+
+/**
+ * @function
+ *
+ * `nghttp3_qpack_stream_context_new` initializes stream context.
+ * |psctx| must be non-NULL pointer.  |stream_id| is stream ID.  |mem|
+ * is a memory allocator.  This function allocates memory for
+ * :type:`nghttp3_qpack_stream_context` itself and assigns its pointer
+ * to |*psctx| if it succeeds.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * :macro:`NGHTTP3_ERR_NOMEM`
+ *     Out of memory.
+ */
+NGHTTP3_EXTERN int
+nghttp3_qpack_stream_context_new(nghttp3_qpack_stream_context **psctx,
+                                 int64_t stream_id, const nghttp3_mem *mem);
+
+/**
+ * @function
+ *
+ * `nghttp3_qpack_stream_context_del` frees memory allocated for
+ * |sctx|.  This function frees memory pointed by |sctx| itself.
+ */
+NGHTTP3_EXTERN void
+nghttp3_qpack_stream_context_del(nghttp3_qpack_stream_context *sctx);
+
+/**
+ * @function
+ *
+ * `nghttp3_qpack_stream_context_get_ricnt` returns required insert
+ * count.
+ */
+NGHTTP3_EXTERN uint64_t
+nghttp3_qpack_stream_context_get_ricnt(nghttp3_qpack_stream_context *sctx);
+
+/**
+ * @function
+ *
+ * `nghttp3_qpack_stream_context_reset` resets the state of |sctx|.
+ * Then it can be reused for an another header block in the same
+ * stream.
+ */
+NGHTTP3_EXTERN
+void nghttp3_qpack_stream_context_reset(nghttp3_qpack_stream_context *sctx);
+
+/**
+ * @struct
+ *
+ * :type:`nghttp3_qpack_decoder` is QPACK decoder.
+ */
+typedef struct nghttp3_qpack_decoder nghttp3_qpack_decoder;
+
+/**
+ * @function
+ *
+ * `nghttp3_qpack_decoder_new` initializes QPACK decoder.  |pdecoder|
+ * must be non-NULL pointer.  |hard_max_dtable_capacity| is the upper
+ * bound of the dynamic table capacity.  |max_blocked_streams| is the
+ * maximum number of streams which can be blocked.  |mem| is a memory
+ * allocator.  This function allocates memory for
+ * :type:`nghttp3_qpack_decoder` itself and assigns its pointer to
+ * |*pdecoder| if it succeeds.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * :macro:`NGHTTP3_ERR_NOMEM`
+ *     Out of memory.
+ */
+NGHTTP3_EXTERN int nghttp3_qpack_decoder_new(nghttp3_qpack_decoder **pdecoder,
+                                             size_t hard_max_dtable_capacity,
+                                             size_t max_blocked_streams,
+                                             const nghttp3_mem *mem);
+
+/**
+ * @function
+ *
+ * `nghttp3_qpack_decoder_del` frees memory allocated for |decoder|.
+ * This function frees memory pointed by |decoder| itself.
+ */
+NGHTTP3_EXTERN void nghttp3_qpack_decoder_del(nghttp3_qpack_decoder *decoder);
+
+/**
+ * @function
+ *
+ * `nghttp3_qpack_decoder_read_encoder` reads encoder stream.  The
+ * buffer pointed by |src| of length |srclen| contains encoder stream.
+ *
+ * This function returns the number of bytes read, or one of the
+ * following negative error codes:
+ *
+ * :macro:`NGHTTP3_ERR_NOMEM`
+ *     Out of memory.
+ * :macro:`NGHTTP3_ERR_QPACK_FATAL`
+ *     |decoder| is in unrecoverable error state and cannot be used
+ *     anymore.
+ * :macro:`NGHTTP3_ERR_QPACK_ENCODER_STREAM`
+ *     Could not interpret encoder stream instruction.
+ */
+NGHTTP3_EXTERN nghttp3_ssize nghttp3_qpack_decoder_read_encoder(
+    nghttp3_qpack_decoder *decoder, const uint8_t *src, size_t srclen);
+
+/**
+ * @function
+ *
+ * `nghttp3_qpack_decoder_get_icnt` returns insert count.
+ */
+NGHTTP3_EXTERN uint64_t
+nghttp3_qpack_decoder_get_icnt(const nghttp3_qpack_decoder *decoder);
+
+/**
+ * @macrosection
+ *
+ * Flags for QPACK decoder
+ */
+
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_QPACK_DECODE_FLAG_NONE` indicates that no flag set.
+ */
+#define NGHTTP3_QPACK_DECODE_FLAG_NONE 0x00u
+
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_QPACK_DECODE_FLAG_EMIT` indicates that a header
+ * field is successfully decoded.
+ */
+#define NGHTTP3_QPACK_DECODE_FLAG_EMIT 0x01u
+
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_QPACK_DECODE_FLAG_FINAL` indicates that all header
+ * fields have been decoded.
+ */
+#define NGHTTP3_QPACK_DECODE_FLAG_FINAL 0x02u
+
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_QPACK_DECODE_FLAG_BLOCKED` indicates that decoding
+ * has been blocked.
+ */
+#define NGHTTP3_QPACK_DECODE_FLAG_BLOCKED 0x04u
+
+/**
+ * @function
+ *
+ * `nghttp3_qpack_decoder_read_request` reads request stream.  The
+ * request stream is given as the buffer pointed by |src| of length
+ * |srclen|.  |sctx| is the stream context and it must be created by
+ * `nghttp3_qpack_stream_context_new()`.  |*pflags| must be non-NULL
+ * pointer.  |nv| must be non-NULL pointer.
+ *
+ * If this function succeeds, it assigns flags to |*pflags|.  If
+ * |*pflags| has :macro:`NGHTTP3_QPACK_DECODE_FLAG_EMIT` set, a
+ * decoded header field is assigned to |nv|.  If |*pflags| has
+ * :macro:`NGHTTP3_QPACK_DECODE_FLAG_FINAL` set, all header fields
+ * have been successfully decoded.  If |*pflags| has
+ * :macro:`NGHTTP3_QPACK_DECODE_FLAG_BLOCKED` set, decoding is blocked
+ * due to required insert count.
+ *
+ * When a header field is decoded, an application receives it in |nv|.
+ * :member:`nv->name <nghttp3_qpack_nv.name>` and :member:`nv->value
+ * <nghttp3_qpack_nv.value>` are reference counted buffer, and their
+ * reference counts are already incremented for application use.
+ * Therefore, when application finishes processing the header field,
+ * it must call `nghttp3_rcbuf_decref(nv->name)
+ * <nghttp3_rcbuf_decref>` and `nghttp3_rcbuf_decref(nv->value)
+ * <nghttp3_rcbuf_decref>` or memory leak might occur.  These
+ * :type:`nghttp3_rcbuf` objects hold the pointer to
+ * :type:`nghttp3_mem` that is passed to `nghttp3_qpack_decoder_new`
+ * (or either `nghttp3_conn_client_new` or `nghttp3_conn_server_new`
+ * if it is used indirectly).  As long as these objects are alive, the
+ * pointed :type:`nghttp3_mem` object must be available.  Otherwise,
+ * `nghttp3_rcbuf_decref` will cause undefined behavior.
+ *
+ * This function returns the number of bytes read, or one of the
+ * following negative error codes:
+ *
+ * :macro:`NGHTTP3_ERR_NOMEM`
+ *     Out of memory.
+ * :macro:`NGHTTP3_ERR_QPACK_FATAL`
+ *     |decoder| is in unrecoverable error state and cannot be used
+ *     anymore.
+ * :macro:`NGHTTP3_ERR_QPACK_DECOMPRESSION_FAILED`
+ *     Could not interpret header block instruction.
+ * :macro:`NGHTTP3_ERR_QPACK_HEADER_TOO_LARGE`
+ *     Header field is too large.
+ */
+NGHTTP3_EXTERN nghttp3_ssize nghttp3_qpack_decoder_read_request(
+    nghttp3_qpack_decoder *decoder, nghttp3_qpack_stream_context *sctx,
+    nghttp3_qpack_nv *nv, uint8_t *pflags, const uint8_t *src, size_t srclen,
+    int fin);
+
+/**
+ * @function
+ *
+ * `nghttp3_qpack_decoder_write_decoder` writes decoder stream into
+ * |dbuf|.
+ *
+ * The caller must ensure that `nghttp3_buf_left(dbuf)
+ * <nghttp3_buf_left>` >=
+ * `nghttp3_qpack_decoder_get_decoder_streamlen(decoder)
+ * <nghttp3_qpack_decoder_get_decoder_streamlen>`.
+ */
+NGHTTP3_EXTERN void
+nghttp3_qpack_decoder_write_decoder(nghttp3_qpack_decoder *decoder,
+                                    nghttp3_buf *dbuf);
+
+/**
+ * @function
+ *
+ * `nghttp3_qpack_decoder_get_decoder_streamlen` returns the length of
+ * decoder stream.
+ */
+NGHTTP3_EXTERN size_t
+nghttp3_qpack_decoder_get_decoder_streamlen(nghttp3_qpack_decoder *decoder);
+
+/**
+ * @function
+ *
+ * `nghttp3_qpack_decoder_cancel_stream` cancels header decoding for
+ * stream denoted by |stream_id|.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * :macro:`NGHTTP3_ERR_NOMEM`
+ *     Out of memory.
+ * :macro:`NGHTTP3_ERR_QPACK_FATAL`
+ *     Decoder stream overflow.
+ */
+NGHTTP3_EXTERN int
+nghttp3_qpack_decoder_cancel_stream(nghttp3_qpack_decoder *decoder,
+                                    int64_t stream_id);
+
+/**
+ * @function
+ *
+ * `nghttp3_qpack_decoder_set_max_dtable_capacity` sets
+ * |max_dtable_capacity| as maximum dynamic table size.
+ * |max_dtable_capacity| must be equal to or smaller than
+ * ``hard_max_dtable_capacity`` parameter of
+ * `nghttp3_qpack_decoder_new`.  Normally, the maximum capacity is
+ * communicated in encoder stream.  This function is provided for
+ * debugging and testing purpose.
+ *
+ * This function returns 0 if it succeeds, or one of the
+ * following negative error codes:
+ *
+ * :macro:`NGHTTP3_ERR_INVALID_ARGUMENT`
+ *     |max_dtable_capacity| exceeds the upper bound of the dynamic
+ *     table capacity.
+ */
+NGHTTP3_EXTERN int
+nghttp3_qpack_decoder_set_max_dtable_capacity(nghttp3_qpack_decoder *decoder,
+                                              size_t max_dtable_capacity);
+
+/**
+ * @function
+ *
+ * `nghttp3_qpack_decoder_set_max_concurrent_streams` tells |decoder|
+ * the maximum number of concurrent streams that a remote endpoint can
+ * open, including both bidirectional and unidirectional streams which
+ * potentially receive QPACK encoded HEADERS frame.  This value is
+ * used as a hint to limit the length of decoder stream.
+ */
+NGHTTP3_EXTERN void
+nghttp3_qpack_decoder_set_max_concurrent_streams(nghttp3_qpack_decoder *decoder,
+                                                 size_t max_concurrent_streams);
+
+/**
+ * @function
+ *
+ * `nghttp3_strerror` returns textual representation of |liberr|.
+ */
+NGHTTP3_EXTERN const char *nghttp3_strerror(int liberr);
+
+/**
+ * @function
+ *
+ * `nghttp3_err_infer_quic_app_error_code` returns a QUIC application
+ * error code which corresponds to |liberr|.
+ */
+NGHTTP3_EXTERN uint64_t nghttp3_err_infer_quic_app_error_code(int liberr);
+
+/**
+ * @functypedef
+ *
+ * :type:`nghttp3_debug_vprintf_callback` is a callback function
+ * invoked when the library outputs debug logging.  The function is
+ * called with arguments suitable for :manpage:`vfprintf(3)`.
+ *
+ * The debug output is only enabled if the library is built with
+ * :macro:`DEBUGBUILD` macro defined.
+ */
+typedef void (*nghttp3_debug_vprintf_callback)(const char *format,
+                                               va_list args);
+
+/**
+ * @function
+ *
+ * `nghttp3_set_debug_vprintf_callback` sets a debug output callback
+ * called by the library when built with :macro:`DEBUGBUILD` macro
+ * defined.  If this option is not used, debug log is written into
+ * standard error output.
+ *
+ * For builds without :macro:`DEBUGBUILD` macro defined, this function
+ * is noop.
+ *
+ * Note that building with :macro:`DEBUGBUILD` may cause significant
+ * performance penalty to libnghttp3 because of extra processing.  It
+ * should be used for debugging purpose only.
+ *
+ * .. Warning::
+ *
+ *   Building with :macro:`DEBUGBUILD` may cause significant
+ *   performance penalty to libnghttp3 because of extra processing.
+ *   It should be used for debugging purpose only.  We write this two
+ *   times because this is important.
+ */
+NGHTTP3_EXTERN void nghttp3_set_debug_vprintf_callback(
+    nghttp3_debug_vprintf_callback debug_vprintf_callback);
+
+/**
+ * @macrosection
+ *
+ * Shutdown related constants
+ */
+
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_SHUTDOWN_NOTICE_STREAM_ID` specifies stream id sent
+ * by a server when it initiates graceful shutdown of the connection
+ * via `nghttp3_conn_submit_shutdown_notice`.
+ */
+#define NGHTTP3_SHUTDOWN_NOTICE_STREAM_ID ((1ull << 62) - 4)
+
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_SHUTDOWN_NOTICE_PUSH_ID` specifies push id sent
+ * by a client when it initiates graceful shutdown of the connection
+ * via `nghttp3_conn_submit_shutdown_notice`.
+ */
+#define NGHTTP3_SHUTDOWN_NOTICE_PUSH_ID ((1ull << 62) - 1)
+
+/**
+ * @struct
+ *
+ * :type:`nghttp3_conn` represents a single HTTP/3 connection.
+ */
+typedef struct nghttp3_conn nghttp3_conn;
+
+/**
+ * @functypedef
+ *
+ * :type:`nghttp3_acked_stream_data` is a callback function which is
+ * invoked when data sent on stream denoted by |stream_id| supplied
+ * from application is acknowledged by remote endpoint.  The number of
+ * bytes acknowledged is given in |datalen|.
+ *
+ * The implementation of this callback must return 0 if it succeeds.
+ * Returning :macro:`NGHTTP3_ERR_CALLBACK_FAILURE` will return to the
+ * caller immediately.  Any values other than 0 is treated as
+ * :macro:`NGHTTP3_ERR_CALLBACK_FAILURE`.
+ */
+typedef int (*nghttp3_acked_stream_data)(nghttp3_conn *conn, int64_t stream_id,
+                                         uint64_t datalen, void *conn_user_data,
+                                         void *stream_user_data);
+
+/**
+ * @functypedef
+ *
+ * :type:`nghttp3_conn_stream_close` is a callback function which is
+ * invoked when a stream identified by |stream_id| is closed.
+ * |app_error_code| indicates the reason of this closure.
+ *
+ * The implementation of this callback must return 0 if it succeeds.
+ * Returning :macro:`NGHTTP3_ERR_CALLBACK_FAILURE` will return to the
+ * caller immediately.  Any values other than 0 is treated as
+ * :macro:`NGHTTP3_ERR_CALLBACK_FAILURE`.
+ */
+typedef int (*nghttp3_stream_close)(nghttp3_conn *conn, int64_t stream_id,
+                                    uint64_t app_error_code,
+                                    void *conn_user_data,
+                                    void *stream_user_data);
+
+/**
+ * @functypedef
+ *
+ * :type:`nghttp3_recv_data` is a callback function which is invoked
+ * when a part of request or response body on stream identified by
+ * |stream_id| is received.  |data| points to the received data and
+ * its length is |datalen|.
+ *
+ * The application is responsible for increasing flow control credit
+ * by |datalen| bytes.
+ *
+ * The implementation of this callback must return 0 if it succeeds.
+ * Returning :macro:`NGHTTP3_ERR_CALLBACK_FAILURE` will return to the
+ * caller immediately.  Any values other than 0 is treated as
+ * :macro:`NGHTTP3_ERR_CALLBACK_FAILURE`.
+ */
+typedef int (*nghttp3_recv_data)(nghttp3_conn *conn, int64_t stream_id,
+                                 const uint8_t *data, size_t datalen,
+                                 void *conn_user_data, void *stream_user_data);
+
+/**
+ * @functypedef
+ *
+ * :type:`nghttp3_deferred_consume` is a callback function which is
+ * invoked when the library consumed |consumed| bytes for a stream
+ * identified by |stream_id|.  This callback is used to notify the
+ * consumed bytes for stream blocked by QPACK decoder.  The
+ * application is responsible for increasing flow control credit by
+ * |consumed| bytes.
+ *
+ * The implementation of this callback must return 0 if it succeeds.
+ * Returning :macro:`NGHTTP3_ERR_CALLBACK_FAILURE` will return to the
+ * caller immediately.  Any values other than 0 is treated as
+ * :macro:`NGHTTP3_ERR_CALLBACK_FAILURE`.
+ */
+typedef int (*nghttp3_deferred_consume)(nghttp3_conn *conn, int64_t stream_id,
+                                        size_t consumed, void *conn_user_data,
+                                        void *stream_user_data);
+
+/**
+ * @functypedef
+ *
+ * :type:`nghttp3_begin_headers` is a callback function which is
+ * invoked when an incoming header block section is started on a
+ * stream denoted by |stream_id|.  Each header field is passed to
+ * application by :type:`nghttp3_recv_header` callback.  And then
+ * :type:`nghttp3_end_headers` is called when a whole header block is
+ * processed.
+ *
+ * The implementation of this callback must return 0 if it succeeds.
+ * Returning :macro:`NGHTTP3_ERR_CALLBACK_FAILURE` will return to the
+ * caller immediately.  Any values other than 0 is treated as
+ * :macro:`NGHTTP3_ERR_CALLBACK_FAILURE`.
+ */
+typedef int (*nghttp3_begin_headers)(nghttp3_conn *conn, int64_t stream_id,
+                                     void *conn_user_data,
+                                     void *stream_user_data);
+
+/**
+ * @functypedef
+ *
+ * :type:`nghttp3_recv_header` is a callback function which is invoked
+ * when a header field is received on a stream denoted by |stream_id|.
+ * |name| contains a field name and |value| contains a field value.
+ * |token| is one of token defined in :type:`nghttp3_qpack_token` or
+ * -1 if no token is defined for |name|.  |flags| is bitwise OR of
+ * zero or more of :macro:`NGHTTP3_NV_FLAG_* <NGHTTP3_NV_FLAG_NONE>`.
+ *
+ * The buffers for |name| and |value| are reference counted. If
+ * application needs to keep them, increment the reference count with
+ * `nghttp3_rcbuf_incref`.  When they are no longer used, call
+ * `nghttp3_rcbuf_decref`.
+ *
+ * The implementation of this callback must return 0 if it succeeds.
+ * Returning :macro:`NGHTTP3_ERR_CALLBACK_FAILURE` will return to the
+ * caller immediately.  Any values other than 0 is treated as
+ * :macro:`NGHTTP3_ERR_CALLBACK_FAILURE`.
+ */
+typedef int (*nghttp3_recv_header)(nghttp3_conn *conn, int64_t stream_id,
+                                   int32_t token, nghttp3_rcbuf *name,
+                                   nghttp3_rcbuf *value, uint8_t flags,
+                                   void *conn_user_data,
+                                   void *stream_user_data);
+
+/**
+ * @functypedef
+ *
+ * :type:`nghttp3_end_headers` is a callback function which is invoked
+ * when an incoming header block has ended.
+ *
+ * If the stream ends with this header block, |fin| is set to nonzero.
+ *
+ * The implementation of this callback must return 0 if it succeeds.
+ * Returning :macro:`NGHTTP3_ERR_CALLBACK_FAILURE` will return to the
+ * caller immediately.  Any values other than 0 is treated as
+ * :macro:`NGHTTP3_ERR_CALLBACK_FAILURE`.
+ */
+typedef int (*nghttp3_end_headers)(nghttp3_conn *conn, int64_t stream_id,
+                                   int fin, void *conn_user_data,
+                                   void *stream_user_data);
+
+/**
+ * @functypedef
+ *
+ * :type:`nghttp3_end_stream` is a callback function which is invoked
+ * when the receiving side of stream is closed.  For server, this
+ * callback function is invoked when HTTP request is received
+ * completely.  For client, this callback function is invoked when
+ * HTTP response is received completely.
+ *
+ * The implementation of this callback must return 0 if it succeeds.
+ * Returning :macro:`NGHTTP3_ERR_CALLBACK_FAILURE` will return to the
+ * caller immediately.  Any values other than 0 is treated as
+ * :macro:`NGHTTP3_ERR_CALLBACK_FAILURE`.
+ */
+typedef int (*nghttp3_end_stream)(nghttp3_conn *conn, int64_t stream_id,
+                                  void *conn_user_data, void *stream_user_data);
+
+/**
+ * @functypedef
+ *
+ * :type:`nghttp3_stop_sending` is a callback function which is
+ * invoked when the library asks application to send STOP_SENDING to
+ * the stream identified by |stream_id|.  |app_error_code| indicates
+ * the reason for this action.
+ *
+ * The implementation of this callback must return 0 if it succeeds.
+ * Returning :macro:`NGHTTP3_ERR_CALLBACK_FAILURE` will return to the
+ * caller immediately.  Any values other than 0 is treated as
+ * :macro:`NGHTTP3_ERR_CALLBACK_FAILURE`.
+ */
+typedef int (*nghttp3_stop_sending)(nghttp3_conn *conn, int64_t stream_id,
+                                    uint64_t app_error_code,
+                                    void *conn_user_data,
+                                    void *stream_user_data);
+
+/**
+ * @functypedef
+ *
+ * :type:`nghttp3_reset_stream` is a callback function which is
+ * invoked when the library asks application to reset stream
+ * identified by |stream_id|.  |app_error_code| indicates the reason
+ * for this action.
+ *
+ * The implementation of this callback must return 0 if it succeeds.
+ * Returning :macro:`NGHTTP3_ERR_CALLBACK_FAILURE` will return to the
+ * caller immediately.  Any values other than 0 is treated as
+ * :macro:`NGHTTP3_ERR_CALLBACK_FAILURE`.
+ */
+typedef int (*nghttp3_reset_stream)(nghttp3_conn *conn, int64_t stream_id,
+                                    uint64_t app_error_code,
+                                    void *conn_user_data,
+                                    void *stream_user_data);
+
+/**
+ * @functypedef
+ *
+ * :type:`nghttp3_shutdown` is a callback function which is invoked
+ * when a shutdown is initiated by the remote endpoint. For client,
+ * |id| contains a stream id of a client initiated stream, for server,
+ * it contains a push id. All client streams with stream id or pushes
+ * with push id equal to or larger than |id| are guaranteed to not be
+ * processed by the remote endpoint.
+ *
+ * Parameter |id| for client can contain a special value
+ * :macro:`NGHTTP3_SHUTDOWN_NOTICE_STREAM_ID` and for server it can
+ * contain special value
+ * :macro:`NGHTTP3_SHUTDOWN_NOTICE_PUSH_ID`. These values signal
+ * request for graceful shutdown of the connection, triggered by
+ * remote endpoint's invocation of
+ * `nghttp3_conn_submit_shutdown_notice`.
+ *
+ * It is possible that this callback is invoked multiple times on a
+ * single connection, however the |id| can only stay the same or
+ * decrease, never increase.
+ *
+ * The implementation of this callback must return 0 if it succeeds.
+ * Returning :macro:`NGHTTP3_ERR_CALLBACK_FAILURE` will return to the
+ * caller immediately.  Any values other than 0 is treated as
+ * :macro:`NGHTTP3_ERR_CALLBACK_FAILURE`.
+ */
+typedef int (*nghttp3_shutdown)(nghttp3_conn *conn, int64_t id,
+                                void *conn_user_data);
+
+#define NGHTTP3_CALLBACKS_VERSION_V1 1
+#define NGHTTP3_CALLBACKS_VERSION NGHTTP3_CALLBACKS_VERSION_V1
+
+/**
+ * @struct
+ *
+ * :type:`nghttp3_callbacks` holds a set of callback functions.
+ */
+typedef struct nghttp3_callbacks {
+  /**
+   * :member:`acked_stream_data` is a callback function which is
+   * invoked when data sent on a particular stream have been
+   * acknowledged by a remote endpoint.
+   */
+  nghttp3_acked_stream_data acked_stream_data;
+  /**
+   * :member:`stream_close` is a callback function which is invoked
+   * when a particular stream has closed.
+   */
+  nghttp3_stream_close stream_close;
+  /**
+   * :member:`recv_data` is a callback function which is invoked when
+   * stream data is received.
+   */
+  nghttp3_recv_data recv_data;
+  /**
+   * :member:`deferred_consume` is a callback function which is
+   * invoked when the library consumed data for a particular stream
+   * which had been blocked for synchronization between streams.
+   */
+  nghttp3_deferred_consume deferred_consume;
+  /**
+   * :member:`begin_headers` is a callback function which is invoked
+   * when a header block has started on a particular stream.
+   */
+  nghttp3_begin_headers begin_headers;
+  /**
+   * :member:`recv_header` is a callback function which is invoked
+   * when a single header field is received on a particular stream.
+   */
+  nghttp3_recv_header recv_header;
+  /**
+   * :member:`end_headers` is a callback function which is invoked
+   * when a header block has ended on a particular stream.
+   */
+  nghttp3_end_headers end_headers;
+  /**
+   * :member:`begin_trailers` is a callback function which is invoked
+   * when a trailer block has started on a particular stream.
+   */
+  nghttp3_begin_headers begin_trailers;
+  /**
+   * :member:`recv_trailer` is a callback function which is invoked
+   * when a single trailer field is received on a particular stream.
+   */
+  nghttp3_recv_header recv_trailer;
+  /**
+   * :member:`end_trailers` is a callback function which is invoked
+   * when a trailer block has ended on a particular stream.
+   */
+  nghttp3_end_headers end_trailers;
+  /**
+   * :member:`stop_sending` is a callback function which is invoked
+   * when the library asks application to send STOP_SENDING to a
+   * particular stream.
+   */
+  nghttp3_stop_sending stop_sending;
+  /**
+   * :member:`end_stream` is a callback function which is invoked when
+   * a receiving side of stream has been closed.
+   */
+  nghttp3_end_stream end_stream;
+  /**
+   * :member:`reset_stream` is a callback function which is invoked
+   * when the library asks application to reset stream (by sending
+   * RESET_STREAM).
+   */
+  nghttp3_reset_stream reset_stream;
+  /**
+   * :member:`shutdown` is a callback function which is invoked when
+   * the remote endpoint has signalled initiation of connection shutdown.
+   */
+  nghttp3_shutdown shutdown;
+} nghttp3_callbacks;
+
+#define NGHTTP3_SETTINGS_VERSION_V1 1
+#define NGHTTP3_SETTINGS_VERSION NGHTTP3_SETTINGS_VERSION_V1
+
+/**
+ * @struct
+ *
+ * :type:`nghttp3_settings` defines HTTP/3 settings.
+ */
+typedef struct nghttp3_settings {
+  /**
+   * :member:`max_field_section_size` specifies the maximum header
+   * section (block) size.
+   */
+  uint64_t max_field_section_size;
+  /**
+   * :member:`qpack_max_dtable_capacity` is the maximum size of QPACK
+   * dynamic table.
+   */
+  size_t qpack_max_dtable_capacity;
+  /**
+   * :member:`qpack_encoder_max_dtable_capacity` is the upper bound of
+   * QPACK dynamic table capacity that the QPACK encoder is willing to
+   * use.  The effective maximum dynamic table capacity is the minimum
+   * of this field and the value of the received
+   * SETTINGS_QPACK_MAX_TABLE_CAPACITY.  If this field is set to 0,
+   * the encoder does not use the dynamic table.
+   */
+  size_t qpack_encoder_max_dtable_capacity;
+  /**
+   * :member:`qpack_blocked_streams` is the maximum number of streams
+   * which can be blocked while they are being decoded.
+   */
+  size_t qpack_blocked_streams;
+  /**
+   * :member:`enable_connect_protocol`, if set to nonzero, enables
+   * Extended CONNECT Method (see
+   * https://datatracker.ietf.org/doc/html/rfc9220).  Client ignores
+   * this field.
+   */
+  int enable_connect_protocol;
+} nghttp3_settings;
+
+/**
+ * @function
+ *
+ * `nghttp3_settings_default` fills |settings| with the default
+ * values.
+ *
+ * - :member:`max_field_section_size
+ *   <nghttp3_settings.max_field_section_size>` = :expr:`((1ull << 62) - 1)`
+ * - :member:`qpack_max_dtable_capacity
+ *   <nghttp3_settings.qpack_max_dtable_capacity>` = 0
+ * - :member:`qpack_encoder_max_dtable_capacity
+ *   <nghttp3_settings.qpack_encoder_max_dtable_capacity>` = 4096
+ * - :member:`qpack_blocked_streams
+ *   <nghttp3_settings.qpack_blocked_streams>` = 0
+ * - :member:`enable_connect_protocol
+ *   <nghttp3_settings.enable_connect_protocol>` = 0
+ */
+NGHTTP3_EXTERN void
+nghttp3_settings_default_versioned(int settings_version,
+                                   nghttp3_settings *settings);
+
+/**
+ * @function
+ *
+ * `nghttp3_conn_client_new` creates :type:`nghttp3_conn` and
+ * initializes it for client use.  The pointer to the object is stored
+ * in |*pconn|.  If |mem| is ``NULL``, the memory allocator returned
+ * by `nghttp3_mem_default` is used.
+ */
+NGHTTP3_EXTERN int
+nghttp3_conn_client_new_versioned(nghttp3_conn **pconn, int callbacks_version,
+                                  const nghttp3_callbacks *callbacks,
+                                  int settings_version,
+                                  const nghttp3_settings *settings,
+                                  const nghttp3_mem *mem, void *conn_user_data);
+
+/**
+ * @function
+ *
+ * `nghttp3_conn_server_new` creates :type:`nghttp3_conn` and
+ * initializes it for server use.  The pointer to the object is stored
+ * in |*pconn|.  If |mem| is ``NULL``, the memory allocator returned
+ * by `nghttp3_mem_default` is used.
+ */
+NGHTTP3_EXTERN int
+nghttp3_conn_server_new_versioned(nghttp3_conn **pconn, int callbacks_version,
+                                  const nghttp3_callbacks *callbacks,
+                                  int settings_version,
+                                  const nghttp3_settings *settings,
+                                  const nghttp3_mem *mem, void *conn_user_data);
+
+/**
+ * @function
+ *
+ * `nghttp3_conn_del` frees resources allocated for |conn|.
+ */
+NGHTTP3_EXTERN void nghttp3_conn_del(nghttp3_conn *conn);
+
+/**
+ * @function
+ *
+ * `nghttp3_conn_bind_control_stream` binds stream denoted by
+ * |stream_id| to outgoing unidirectional control stream.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * :macro:`NGHTTP3_ERR_INVALID_STATE`
+ *     Control stream has already corresponding stream ID.
+ *
+ * TBD
+ */
+NGHTTP3_EXTERN int nghttp3_conn_bind_control_stream(nghttp3_conn *conn,
+                                                    int64_t stream_id);
+
+/**
+ * @function
+ *
+ * `nghttp3_conn_bind_qpack_streams` binds stream denoted by
+ * |qenc_stream_id| to outgoing QPACK encoder stream and stream
+ * denoted by |qdec_stream_id| to outgoing QPACK encoder stream.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * :macro:`NGHTTP3_ERR_INVALID_STATE`
+ *     QPACK encoder/decoder stream have already corresponding stream
+ *     IDs.
+ *
+ * TBD
+ */
+NGHTTP3_EXTERN int nghttp3_conn_bind_qpack_streams(nghttp3_conn *conn,
+                                                   int64_t qenc_stream_id,
+                                                   int64_t qdec_stream_id);
+
+/**
+ * @function
+ *
+ * `nghttp3_conn_read_stream` reads data |src| of length |srclen| on
+ * stream identified by |stream_id|.  It returns the number of bytes
+ * consumed.  The "consumed" means that application can increase flow
+ * control credit (both stream and connection) of underlying QUIC
+ * connection by that amount.  It does not include the amount of data
+ * carried by DATA frame which contains application data (excluding
+ * any control or QPACK unidirectional streams) .  See
+ * :type:`nghttp3_recv_data` to handle those bytes.  If |fin| is
+ * nonzero, this is the last data from remote endpoint in this stream.
+ */
+NGHTTP3_EXTERN nghttp3_ssize nghttp3_conn_read_stream(nghttp3_conn *conn,
+                                                      int64_t stream_id,
+                                                      const uint8_t *src,
+                                                      size_t srclen, int fin);
+
+/**
+ * @function
+ *
+ * `nghttp3_conn_writev_stream` stores stream data to send to |vec| of
+ * length |veccnt| and returns the number of nghttp3_vec object in
+ * which it stored data.  It stores stream ID to |*pstream_id|.  An
+ * application has to call `nghttp3_conn_add_write_offset` to inform
+ * |conn| of the actual number of bytes that underlying QUIC stack
+ * accepted.  |*pfin| will be nonzero if this is the last data to
+ * send.  If there is no stream to write data or send fin, this
+ * function returns 0, and -1 is assigned to |*pstream_id|.  This
+ * function may return 0 and |*pstream_id| is not -1 and |*pfin| is
+ * nonzero.  It means 0 length data to |*pstream_id| and it is the
+ * last data to the stream.  They must be passed to QUIC stack, and
+ * they are accepted, the application has to call
+ * `nghttp3_conn_add_write_offset`.
+ */
+NGHTTP3_EXTERN nghttp3_ssize nghttp3_conn_writev_stream(nghttp3_conn *conn,
+                                                        int64_t *pstream_id,
+                                                        int *pfin,
+                                                        nghttp3_vec *vec,
+                                                        size_t veccnt);
+
+/**
+ * @function
+ *
+ * `nghttp3_conn_add_write_offset` tells |conn| the number of bytes
+ * |n| for stream denoted by |stream_id| QUIC stack accepted.
+ *
+ * If stream has no data to send but just sends fin (closing the write
+ * side of a stream), the number of bytes sent is 0.  It is important
+ * to call this function even if |n| is 0 in this case.  It is safe to
+ * call this function if |n| is 0.
+ *
+ * `nghttp3_conn_writev_stream` must be called before calling this
+ * function to get data to send, and those data must be fed into QUIC
+ * stack.
+ */
+NGHTTP3_EXTERN int nghttp3_conn_add_write_offset(nghttp3_conn *conn,
+                                                 int64_t stream_id, size_t n);
+
+/**
+ * @function
+ *
+ * `nghttp3_conn_add_ack_offset` tells |conn| the number of bytes |n|
+ * for stream denoted by |stream_id| QUIC stack has acknowledged.
+ */
+NGHTTP3_EXTERN int nghttp3_conn_add_ack_offset(nghttp3_conn *conn,
+                                               int64_t stream_id, uint64_t n);
+
+/**
+ * @function
+ *
+ * `nghttp3_conn_block_stream` tells the library that stream
+ * identified by |stream_id| is blocked due to QUIC flow control.
+ */
+NGHTTP3_EXTERN void nghttp3_conn_block_stream(nghttp3_conn *conn,
+                                              int64_t stream_id);
+
+/**
+ * @function
+ *
+ * `nghttp3_conn_unblock_stream` tells the library that stream
+ * identified by |stream_id| which was blocked by QUIC flow control is
+ * unblocked.
+ */
+NGHTTP3_EXTERN int nghttp3_conn_unblock_stream(nghttp3_conn *conn,
+                                               int64_t stream_id);
+
+/**
+ * @function
+ *
+ * `nghttp3_conn_is_stream_writable` returns nonzero if a stream
+ * identified by |stream_id| is writable.  It is not writable if:
+ *
+ * - the stream does not exist; or,
+ * - the stream is closed (e.g., `nghttp3_conn_close_stream` is
+ *   called); or,
+ * - the stream is QUIC flow control blocked (e.g.,
+ *   `nghttp3_conn_block_stream` is called); or,
+ * - the stream is input data blocked (e.g.,
+ *   :macro:`NGHTTP3_ERR_WOULDBLOCK` is returned from
+ *   :type:`nghttp3_read_data_callback`); or,
+ * - the stream is half-closed local (e.g.,
+ *   `nghttp3_conn_shutdown_stream_write` is called).
+ */
+NGHTTP3_EXTERN int nghttp3_conn_is_stream_writable(nghttp3_conn *conn,
+                                                   int64_t stream_id);
+
+/**
+ * @function
+ *
+ * `nghttp3_conn_shutdown_stream_write` tells the library that any
+ * further write operation to stream identified by |stream_id| is
+ * prohibited.  This works like `nghttp3_conn_block_stream`, but it
+ * cannot be unblocked by `nghttp3_conn_unblock_stream`.
+ */
+NGHTTP3_EXTERN void nghttp3_conn_shutdown_stream_write(nghttp3_conn *conn,
+                                                       int64_t stream_id);
+
+/**
+ * @function
+ *
+ * `nghttp3_conn_shutdown_stream_read` tells the library that
+ * read-side of stream denoted by |stream_id| is abruptly closed and
+ * any further incoming data and pending stream data should be
+ * discarded.
+ */
+NGHTTP3_EXTERN int nghttp3_conn_shutdown_stream_read(nghttp3_conn *conn,
+                                                     int64_t stream_id);
+
+/**
+ * @function
+ *
+ * `nghttp3_conn_resume_stream` resumes stream identified by
+ * |stream_id| which was previously unable to provide data.
+ */
+NGHTTP3_EXTERN int nghttp3_conn_resume_stream(nghttp3_conn *conn,
+                                              int64_t stream_id);
+
+/**
+ * @function
+ *
+ * `nghttp3_conn_close_stream` closes stream identified by
+ * |stream_id|.  |app_error_code| is the reason of the closure.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * :macro:`NGHTTP3_ERR_STREAM_NOT_FOUND`
+ *     Stream not found.
+ * :macro:`NGHTTP3_ERR_H3_CLOSED_CRITICAL_STREAM`
+ *     A critical stream is closed.
+ * :macro:`NGHTTP3_ERR_CALLBACK_FAILURE`
+ *     User callback failed
+ */
+NGHTTP3_EXTERN int nghttp3_conn_close_stream(nghttp3_conn *conn,
+                                             int64_t stream_id,
+                                             uint64_t app_error_code);
+
+/**
+ * @macrosection
+ *
+ * Data flags
+ */
+
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_DATA_FLAG_NONE` indicates no flag set.
+ */
+#define NGHTTP3_DATA_FLAG_NONE 0x00u
+
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_DATA_FLAG_EOF` indicates that all request or
+ * response body has been provided to the library.  It also indicates
+ * that sending side of stream is closed unless
+ * :macro:`NGHTTP3_DATA_FLAG_NO_END_STREAM` is given at the same time.
+ */
+#define NGHTTP3_DATA_FLAG_EOF 0x01u
+
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_DATA_FLAG_NO_END_STREAM` indicates that sending
+ * side of stream is not closed even if :macro:`NGHTTP3_DATA_FLAG_EOF`
+ * is set.  Usually this flag is used to send trailer fields with
+ * `nghttp3_conn_submit_trailers()`.  If
+ * `nghttp3_conn_submit_trailers()` has been called, regardless of
+ * this flag, the submitted trailer fields are sent.
+ */
+#define NGHTTP3_DATA_FLAG_NO_END_STREAM 0x02u
+
+/**
+ * @function
+ *
+ * `nghttp3_conn_set_max_client_streams_bidi` tells |conn| the
+ * cumulative number of bidirectional streams that client can open.
+ */
+NGHTTP3_EXTERN void
+nghttp3_conn_set_max_client_streams_bidi(nghttp3_conn *conn,
+                                         uint64_t max_streams);
+
+/**
+ * @function
+ *
+ * `nghttp3_conn_set_max_concurrent_streams` tells |conn| the maximum
+ * number of concurrent streams that a remote endpoint can open,
+ * including both bidirectional and unidirectional streams which
+ * potentially receive QPACK encoded HEADERS frame.  This value is
+ * used as a hint to limit the internal resource consumption.
+ */
+NGHTTP3_EXTERN void
+nghttp3_conn_set_max_concurrent_streams(nghttp3_conn *conn,
+                                        size_t max_concurrent_streams);
+
+/**
+ * @functypedef
+ *
+ * :type:`nghttp3_read_data_callback` is a callback function invoked
+ * when the library asks an application to provide stream data for a
+ * stream denoted by |stream_id|.
+ *
+ * The library provides |vec| of length |veccnt| to the application.
+ * The application should fill data and its length to |vec|.  It has
+ * to return the number of the filled objects.  The application must
+ * retain data until they are safe to free.  It is notified by
+ * :type:`nghttp3_acked_stream_data` callback.
+ *
+ * If this is the last data to send (or there is no data to send
+ * because all data have been sent already), set
+ * :macro:`NGHTTP3_DATA_FLAG_EOF` to |*pflags|.
+ *
+ * If the application is unable to provide data temporarily, return
+ * :macro:`NGHTTP3_ERR_WOULDBLOCK`.  When it is ready to provide
+ * data, call `nghttp3_conn_resume_stream()`.
+ *
+ * The callback should return the number of objects in |vec| that the
+ * application filled if it succeeds, or
+ * :macro:`NGHTTP3_ERR_CALLBACK_FAILURE`.
+ *
+ * TODO Add NGHTTP3_ERR_TEMPORAL_CALLBACK_FAILURE to reset just this
+ * stream.
+ */
+typedef nghttp3_ssize (*nghttp3_read_data_callback)(
+    nghttp3_conn *conn, int64_t stream_id, nghttp3_vec *vec, size_t veccnt,
+    uint32_t *pflags, void *conn_user_data, void *stream_user_data);
+
+/**
+ * @struct
+ *
+ * :type:`nghttp3_data_reader` specifies the way how to generate
+ * request or response body.
+ */
+typedef struct nghttp3_data_reader {
+  /**
+   * :member:`read_data` is a callback function to generate body.
+   */
+  nghttp3_read_data_callback read_data;
+} nghttp3_data_reader;
+
+/**
+ * @function
+ *
+ * `nghttp3_conn_submit_request` submits HTTP request header fields
+ * and body on the stream identified by |stream_id|.  |stream_id| must
+ * be a client initiated bidirectional stream.  Only client can submit
+ * HTTP request.  |nva| of length |nvlen| specifies HTTP request
+ * header fields.  |dr| specifies a request body.  If there is no
+ * request body, specify NULL.  If |dr| is NULL, it implies the end of
+ * stream.  |stream_user_data| is an opaque pointer attached to the
+ * stream.
+ */
+NGHTTP3_EXTERN int nghttp3_conn_submit_request(
+    nghttp3_conn *conn, int64_t stream_id, const nghttp3_nv *nva, size_t nvlen,
+    const nghttp3_data_reader *dr, void *stream_user_data);
+
+/**
+ * @function
+ *
+ * `nghttp3_conn_submit_info` submits HTTP non-final response header
+ * fields on the stream identified by |stream_id|.  |nva| of length
+ * |nvlen| specifies HTTP response header fields.
+ */
+NGHTTP3_EXTERN int nghttp3_conn_submit_info(nghttp3_conn *conn,
+                                            int64_t stream_id,
+                                            const nghttp3_nv *nva,
+                                            size_t nvlen);
+
+/**
+ * @function
+ *
+ * `nghttp3_conn_submit_response` submits HTTP response header fields
+ * and body on the stream identified by |stream_id|.  |nva| of length
+ * |nvlen| specifies HTTP response header fields.  |dr| specifies a
+ * response body.  If there is no response body, specify NULL.  If
+ * |dr| is NULL, it implies the end of stream.
+ */
+NGHTTP3_EXTERN int nghttp3_conn_submit_response(nghttp3_conn *conn,
+                                                int64_t stream_id,
+                                                const nghttp3_nv *nva,
+                                                size_t nvlen,
+                                                const nghttp3_data_reader *dr);
+
+/**
+ * @function
+ *
+ * `nghttp3_conn_submit_trailers` submits HTTP trailer fields on the
+ * stream identified by |stream_id|.  |nva| of length |nvlen|
+ * specifies HTTP trailer fields.  Calling this function implies the
+ * end of stream.
+ */
+NGHTTP3_EXTERN int nghttp3_conn_submit_trailers(nghttp3_conn *conn,
+                                                int64_t stream_id,
+                                                const nghttp3_nv *nva,
+                                                size_t nvlen);
+
+/**
+ * @function
+ *
+ * `nghttp3_conn_submit_shutdown_notice` notifies the other endpoint
+ * to stop creating new stream.  After a couple of RTTs later, call
+ * `nghttp3_conn_shutdown` to start graceful shutdown.
+ */
+NGHTTP3_EXTERN int nghttp3_conn_submit_shutdown_notice(nghttp3_conn *conn);
+
+/**
+ * @function
+ *
+ * `nghttp3_conn_shutdown` starts graceful shutdown.  It should be
+ * called after `nghttp3_conn_submit_shutdown_notice` and a couple of
+ * RTT.  After calling this function, the local endpoint starts
+ * rejecting new incoming streams.  The existing streams are processed
+ * normally.
+ */
+NGHTTP3_EXTERN int nghttp3_conn_shutdown(nghttp3_conn *conn);
+
+/**
+ * @function
+ *
+ * `nghttp3_conn_set_stream_user_data` sets |stream_user_data| to the
+ * stream identified by |stream_id|.
+ */
+NGHTTP3_EXTERN int nghttp3_conn_set_stream_user_data(nghttp3_conn *conn,
+                                                     int64_t stream_id,
+                                                     void *stream_user_data);
+
+/**
+ * @function
+ *
+ * `nghttp3_conn_get_frame_payload_left` returns the number of bytes
+ * left to read current frame payload for a stream denoted by
+ * |stream_id|.  If no such stream is found, it returns 0.
+ */
+NGHTTP3_EXTERN uint64_t nghttp3_conn_get_frame_payload_left(nghttp3_conn *conn,
+                                                            int64_t stream_id);
+
+/**
+ * @macrosection
+ *
+ * HTTP stream priority flags
+ */
+
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_DEFAULT_URGENCY` is the default urgency level.
+ */
+#define NGHTTP3_DEFAULT_URGENCY 3
+
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_URGENCY_HIGH` is the highest urgency level.
+ */
+#define NGHTTP3_URGENCY_HIGH 0
+
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_URGENCY_LOW` is the lowest urgency level.
+ */
+#define NGHTTP3_URGENCY_LOW 7
+
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_URGENCY_LEVELS` is the number of urgency levels.
+ */
+#define NGHTTP3_URGENCY_LEVELS (NGHTTP3_URGENCY_LOW + 1)
+
+/**
+ * @struct
+ *
+ * :type:`nghttp3_pri` represents HTTP priority.
+ */
+typedef struct nghttp3_pri {
+  /**
+   * :member:`urgency` is the urgency of a stream, it must be in
+   * [:macro:`NGHTTP3_URGENCY_HIGH`, :macro:`NGHTTP3_URGENCY_LOW`],
+   * inclusive, and 0 is the highest urgency.
+   */
+  uint32_t urgency;
+  /**
+   * :member:`inc` indicates that a content can be processed
+   * incrementally or not.  If inc is 0, it cannot be processed
+   * incrementally.  If inc is 1, it can be processed incrementally.
+   * Other value is not permitted.
+   */
+  int inc;
+} nghttp3_pri;
+
+/**
+ * @function
+ *
+ * `nghttp3_conn_get_stream_priority` stores stream priority of a
+ * stream denoted by |stream_id| into |*dest|.  |stream_id| must
+ * identify client initiated bidirectional stream.  Only server can
+ * use this function.
+ *
+ * This function must not be called if |conn| is initialized as
+ * client.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * :macro:`NGHTTP3_ERR_STREAM_NOT_FOUND`
+ *     Stream not found.
+ */
+NGHTTP3_EXTERN int nghttp3_conn_get_stream_priority(nghttp3_conn *conn,
+                                                    nghttp3_pri *dest,
+                                                    int64_t stream_id);
+
+/**
+ * @function
+ *
+ * `nghttp3_conn_set_stream_priority` updates priority of a stream
+ * denoted by |stream_id| with the value pointed by |pri|.
+ * |stream_id| must identify client initiated bidirectional stream.
+ *
+ * Both client and server can update stream priority with this
+ * function.
+ *
+ * If server updates stream priority with this function, it completely
+ * overrides stream priority set by client and the attempts to update
+ * priority by client are ignored.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * :macro:`NGHTTP3_ERR_INVALID_ARGUMENT`
+ *     |stream_id| is not a client initiated bidirectional stream ID.
+ * :macro:`NGHTTP3_ERR_STREAM_NOT_FOUND`
+ *     Stream not found.
+ * :macro:`NGHTTP3_ERR_NOMEM`
+ *     Out of memory.
+ */
+NGHTTP3_EXTERN int nghttp3_conn_set_stream_priority(nghttp3_conn *conn,
+                                                    int64_t stream_id,
+                                                    const nghttp3_pri *pri);
+
+/**
+ * @function
+ *
+ * `nghttp3_conn_is_remote_qpack_encoder_stream` returns nonzero if a
+ * stream denoted by |stream_id| is QPACK encoder stream of a remote
+ * endpoint.
+ */
+NGHTTP3_EXTERN int
+nghttp3_conn_is_remote_qpack_encoder_stream(nghttp3_conn *conn,
+                                            int64_t stream_id);
+
+/**
+ * @function
+ *
+ * `nghttp3_vec_len` returns the sum of length in |vec| of |cnt|
+ * elements.
+ */
+NGHTTP3_EXTERN uint64_t nghttp3_vec_len(const nghttp3_vec *vec, size_t cnt);
+
+/**
+ * @function
+ *
+ * `nghttp3_check_header_name` returns nonzero if HTTP header field
+ * name |name| of length |len| is valid according to
+ * :rfc:`7230#section-3.2`.
+ *
+ * Because this is a header field name in HTTP/3, the upper cased
+ * alphabet is treated as error.
+ */
+NGHTTP3_EXTERN int nghttp3_check_header_name(const uint8_t *name, size_t len);
+
+/**
+ * @function
+ *
+ * `nghttp3_check_header_value` returns nonzero if HTTP header field
+ * value |value| of length |len| is valid according to
+ * :rfc:`7230#section-3.2`.
+ */
+NGHTTP3_EXTERN int nghttp3_check_header_value(const uint8_t *value, size_t len);
+
+/**
+ * @function
+ *
+ * `nghttp3_http_parse_priority` parses priority HTTP header field
+ * stored in the buffer pointed by |value| of length |len|.  If it
+ * successfully processed header field value, it stores the result
+ * into |*dest|.  This function just overwrites what it sees in the
+ * header field value and does not initialize any field in |*dest|.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * :macro:`NGHTTP3_ERR_INVALID_ARGUMENT`
+ *     The function could not parse the provided value.
+ */
+NGHTTP3_EXTERN int nghttp3_http_parse_priority(nghttp3_pri *dest,
+                                               const uint8_t *value,
+                                               size_t len);
+
+/**
+ * @macrosection
+ *
+ * nghttp3_info flags
+ */
+
+/**
+ * @macro
+ *
+ * :macro:`NGHTTP3_VERSION_AGE` is the age of :type:`nghttp3_info`.
+ */
+#define NGHTTP3_VERSION_AGE 1
+
+/**
+ * @struct
+ *
+ * :type:`nghttp3_info` is what `nghttp3_version()` returns.  It holds
+ * information about the particular nghttp3 version.
+ */
+typedef struct nghttp3_info {
+  /**
+   * :member:`age` is the age of this struct.  This instance of
+   * nghttp3 sets it to :macro:`NGHTTP3_VERSION_AGE` but a future
+   * version may bump it and add more struct fields at the bottom
+   */
+  int age;
+  /**
+   * :member:`version_num` is the :macro:`NGHTTP3_VERSION_NUM` number
+   * (since age ==1)
+   */
+  int version_num;
+  /**
+   * :member:`version_str` points to the :macro:`NGHTTP3_VERSION`
+   * string (since age ==1)
+   */
+  const char *version_str;
+  /* -------- the above fields all exist when age == 1 */
+} nghttp3_info;
+
+/**
+ * @function
+ *
+ * `nghttp3_version` returns a pointer to a :type:`nghttp3_info`
+ * struct with version information about the run-time library in use.
+ * The |least_version| argument can be set to a 24 bit numerical value
+ * for the least accepted version number and if the condition is not
+ * met, this function will return a ``NULL``.  Pass in 0 to skip the
+ * version checking.
+ */
+NGHTTP3_EXTERN const nghttp3_info *nghttp3_version(int least_version);
+
+/**
+ * @function
+ *
+ * `nghttp3_err_is_fatal` returns nonzero if |liberr| is a fatal
+ * error.  |liberr| must be one of nghttp3 library error codes (which
+ * is defined as NGHTTP3_ERR_* macro, such as
+ * :macro:`NGHTTP3_ERR_NOMEM`).
+ */
+NGHTTP3_EXTERN int nghttp3_err_is_fatal(int liberr);
+
+/*
+ * Versioned function wrappers
+ */
+
+/*
+ * `nghttp3_settings_default` is a wrapper around
+ * `nghttp3_settings_default_versioned` to set the correct struct
+ * version.
+ */
+#define nghttp3_settings_default(SETTINGS)                                     \
+  nghttp3_settings_default_versioned(NGHTTP3_SETTINGS_VERSION, (SETTINGS))
+
+/*
+ * `nghttp3_conn_client_new` is a wrapper around
+ * `nghttp3_conn_client_new_versioned` to set the correct struct
+ * version.
+ */
+#define nghttp3_conn_client_new(PCONN, CALLBACKS, SETTINGS, MEM, USER_DATA)    \
+  nghttp3_conn_client_new_versioned((PCONN), NGHTTP3_CALLBACKS_VERSION,        \
+                                    (CALLBACKS), NGHTTP3_SETTINGS_VERSION,     \
+                                    (SETTINGS), (MEM), (USER_DATA))
+
+/*
+ * `nghttp3_conn_server_new` is a wrapper around
+ * `nghttp3_conn_server_new_versioned` to set the correct struct
+ * version.
+ */
+#define nghttp3_conn_server_new(PCONN, CALLBACKS, SETTINGS, MEM, USER_DATA)    \
+  nghttp3_conn_server_new_versioned((PCONN), NGHTTP3_CALLBACKS_VERSION,        \
+                                    (CALLBACKS), NGHTTP3_SETTINGS_VERSION,     \
+                                    (SETTINGS), (MEM), (USER_DATA))
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* NGHTTP3_H */
diff --git a/lib/includes/nghttp3/version.h.in b/lib/includes/nghttp3/version.h.in
new file mode 100644
index 0000000..1d86147
--- /dev/null
+++ b/lib/includes/nghttp3/version.h.in
@@ -0,0 +1,46 @@
+/*
+ * nghttp3
+ *
+ * Copyright (c) 2019 nghttp3 contributors
+ * Copyright (c) 2016 ngtcp2 contributors
+ *
+ * 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 NGHTTP3_VERSION_H
+#define NGHTTP3_VERSION_H
+
+/**
+ * @macro
+ *
+ * Version number of the nghttp3 library release.
+ */
+#define NGHTTP3_VERSION "@PACKAGE_VERSION@"
+
+/**
+ * @macro
+ *
+ * Numerical representation of the version number of the nghttp3
+ * library release. This is a 24 bit number with 8 bits for major
+ * number, 8 bits for minor and 8 bits for patch. Version 1.2.3
+ * becomes 0x010203.
+ */
+#define NGHTTP3_VERSION_NUM @PACKAGE_VERSION_NUM@
+
+#endif /* NGHTTP3_VERSION_H */