Merging upstream version 1.44.3.

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

1 files changed, 2116 insertions, 0 deletions

diff --git a/web/server/h2o/libh2o/include/h2o.h b/web/server/h2o/libh2o/include/h2o.h
new file mode 100644
index 000000000..57877bd12
--- /dev/null
+++ b/web/server/h2o/libh2o/include/h2o.h
@@ -0,0 +1,2116 @@
+/*
+ * Copyright (c) 2014-2016 DeNA Co., Ltd., Kazuho Oku, Fastly, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+#ifndef h2o_h
+#define h2o_h
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <assert.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+#include <stdlib.h>
+#include <sys/time.h>
+#include <sys/socket.h>
+#include <time.h>
+#include <unistd.h>
+#include <openssl/ssl.h>
+#include "h2o/filecache.h"
+#include "h2o/hostinfo.h"
+#include "h2o/memcached.h"
+#include "h2o/linklist.h"
+#include "h2o/http1client.h"
+#include "h2o/memory.h"
+#include "h2o/multithread.h"
+#include "h2o/rand.h"
+#include "h2o/socket.h"
+#include "h2o/string_.h"
+#include "h2o/time_.h"
+#include "h2o/timeout.h"
+#include "h2o/url.h"
+#include "h2o/version.h"
+
+#ifndef H2O_USE_BROTLI
+/* disabled for all but the standalone server, since the encoder is written in C++ */
+#define H2O_USE_BROTLI 0
+#endif
+
+#ifndef H2O_MAX_HEADERS
+#define H2O_MAX_HEADERS 100
+#endif
+#ifndef H2O_MAX_REQLEN
+#define H2O_MAX_REQLEN (8192 + 4096 * (H2O_MAX_HEADERS))
+#endif
+
+#ifndef H2O_MAX_TOKENS
+#define H2O_MAX_TOKENS 100
+#endif
+
+#ifndef H2O_SOMAXCONN
+/* simply use a large value, and let the kernel clip it to the internal max */
+#define H2O_SOMAXCONN 65535
+#endif
+
+#define H2O_DEFAULT_MAX_REQUEST_ENTITY_SIZE (1024 * 1024 * 1024)
+#define H2O_DEFAULT_MAX_DELEGATIONS 5
+#define H2O_DEFAULT_HANDSHAKE_TIMEOUT_IN_SECS 10
+#define H2O_DEFAULT_HANDSHAKE_TIMEOUT (H2O_DEFAULT_HANDSHAKE_TIMEOUT_IN_SECS * 1000)
+#define H2O_DEFAULT_HTTP1_REQ_TIMEOUT_IN_SECS 10
+#define H2O_DEFAULT_HTTP1_REQ_TIMEOUT (H2O_DEFAULT_HTTP1_REQ_TIMEOUT_IN_SECS * 1000)
+#define H2O_DEFAULT_HTTP1_UPGRADE_TO_HTTP2 1
+#define H2O_DEFAULT_HTTP2_IDLE_TIMEOUT_IN_SECS 10
+#define H2O_DEFAULT_HTTP2_IDLE_TIMEOUT (H2O_DEFAULT_HTTP2_IDLE_TIMEOUT_IN_SECS * 1000)
+#define H2O_DEFAULT_HTTP2_GRACEFUL_SHUTDOWN_TIMEOUT_IN_SECS 0 /* no timeout */
+#define H2O_DEFAULT_HTTP2_GRACEFUL_SHUTDOWN_TIMEOUT (H2O_DEFAULT_HTTP2_GRACEFUL_SHUTDOWN_TIMEOUT_IN_SECS * 1000)
+#define H2O_DEFAULT_PROXY_IO_TIMEOUT_IN_SECS 30
+#define H2O_DEFAULT_PROXY_IO_TIMEOUT (H2O_DEFAULT_PROXY_IO_TIMEOUT_IN_SECS * 1000)
+#define H2O_DEFAULT_PROXY_WEBSOCKET_TIMEOUT_IN_SECS 300
+#define H2O_DEFAULT_PROXY_WEBSOCKET_TIMEOUT (H2O_DEFAULT_PROXY_WEBSOCKET_TIMEOUT_IN_SECS * 1000)
+#define H2O_DEFAULT_PROXY_SSL_SESSION_CACHE_CAPACITY 4096
+#define H2O_DEFAULT_PROXY_SSL_SESSION_CACHE_DURATION 86400000 /* 24 hours */
+
+typedef struct st_h2o_conn_t h2o_conn_t;
+typedef struct st_h2o_context_t h2o_context_t;
+typedef struct st_h2o_req_t h2o_req_t;
+typedef struct st_h2o_ostream_t h2o_ostream_t;
+typedef struct st_h2o_configurator_command_t h2o_configurator_command_t;
+typedef struct st_h2o_configurator_t h2o_configurator_t;
+typedef struct st_h2o_hostconf_t h2o_hostconf_t;
+typedef struct st_h2o_globalconf_t h2o_globalconf_t;
+typedef struct st_h2o_mimemap_t h2o_mimemap_t;
+typedef struct st_h2o_logconf_t h2o_logconf_t;
+typedef struct st_h2o_headers_command_t h2o_headers_command_t;
+
+/**
+ * a predefined, read-only, fast variant of h2o_iovec_t, defined in h2o/token.h
+ */
+typedef struct st_h2o_token_t {
+    h2o_iovec_t buf;
+    char http2_static_table_name_index; /* non-zero if any */
+    unsigned char proxy_should_drop_for_req : 1;
+    unsigned char proxy_should_drop_for_res : 1;
+    unsigned char is_init_header_special : 1;
+    unsigned char http2_should_reject : 1;
+    unsigned char copy_for_push_request : 1;
+    unsigned char dont_compress : 1;
+} h2o_token_t;
+
+#include "h2o/token.h"
+
+/**
+ * basic structure of a handler (an object that MAY generate a response)
+ * The handlers should register themselves to h2o_context_t::handlers.
+ */
+typedef struct st_h2o_handler_t {
+    size_t _config_slot;
+    void (*on_context_init)(struct st_h2o_handler_t *self, h2o_context_t *ctx);
+    void (*on_context_dispose)(struct st_h2o_handler_t *self, h2o_context_t *ctx);
+    void (*dispose)(struct st_h2o_handler_t *self);
+    int (*on_req)(struct st_h2o_handler_t *self, h2o_req_t *req);
+} h2o_handler_t;
+
+/**
+ * basic structure of a filter (an object that MAY modify a response)
+ * The filters should register themselves to h2o_context_t::filters.
+ */
+typedef struct st_h2o_filter_t {
+    size_t _config_slot;
+    void (*on_context_init)(struct st_h2o_filter_t *self, h2o_context_t *ctx);
+    void (*on_context_dispose)(struct st_h2o_filter_t *self, h2o_context_t *ctx);
+    void (*dispose)(struct st_h2o_filter_t *self);
+    void (*on_setup_ostream)(struct st_h2o_filter_t *self, h2o_req_t *req, h2o_ostream_t **slot);
+} h2o_filter_t;
+
+/**
+ * basic structure of a logger (an object that MAY log a request)
+ * The loggers should register themselves to h2o_context_t::loggers.
+ */
+typedef struct st_h2o_logger_t {
+    size_t _config_slot;
+    void (*on_context_init)(struct st_h2o_logger_t *self, h2o_context_t *ctx);
+    void (*on_context_dispose)(struct st_h2o_logger_t *self, h2o_context_t *ctx);
+    void (*dispose)(struct st_h2o_logger_t *self);
+    void (*log_access)(struct st_h2o_logger_t *self, h2o_req_t *req);
+} h2o_logger_t;
+
+/**
+ * contains stringified representations of a timestamp
+ */
+typedef struct st_h2o_timestamp_string_t {
+    char rfc1123[H2O_TIMESTR_RFC1123_LEN + 1];
+    char log[H2O_TIMESTR_LOG_LEN + 1];
+} h2o_timestamp_string_t;
+
+/**
+ * a timestamp.
+ * Applications should call h2o_get_timestamp to obtain a timestamp.
+ */
+typedef struct st_h2o_timestamp_t {
+    struct timeval at;
+    h2o_timestamp_string_t *str;
+} h2o_timestamp_t;
+
+typedef struct st_h2o_casper_conf_t {
+    /**
+     * capacity bits (0 to disable casper)
+     */
+    unsigned capacity_bits;
+    /**
+     * whether if all type of files should be tracked (or only the blocking assets)
+     */
+    int track_all_types;
+} h2o_casper_conf_t;
+
+typedef struct st_h2o_envconf_t {
+    /**
+     * parent
+     */
+    struct st_h2o_envconf_t *parent;
+    /**
+     * list of names to be unset
+     */
+    h2o_iovec_vector_t unsets;
+    /**
+     * list of name-value pairs to be set
+     */
+    h2o_iovec_vector_t sets;
+} h2o_envconf_t;
+
+typedef struct st_h2o_pathconf_t {
+    /**
+     * globalconf to which the pathconf belongs
+     */
+    h2o_globalconf_t *global;
+    /**
+     * pathname in lower case, may or may not have "/" at last, NULL terminated, or is {NULL,0} if is fallback or extension-level
+     */
+    h2o_iovec_t path;
+    /**
+     * list of handlers
+     */
+    H2O_VECTOR(h2o_handler_t *) handlers;
+    /**
+     * list of filters
+     */
+    H2O_VECTOR(h2o_filter_t *) filters;
+    /**
+     * list of loggers (h2o_logger_t)
+     */
+    H2O_VECTOR(h2o_logger_t *) loggers;
+    /**
+     * mimemap
+     */
+    h2o_mimemap_t *mimemap;
+    /**
+     * env
+     */
+    h2o_envconf_t *env;
+    /**
+     * error-log
+     */
+    struct {
+        /**
+         * if request-level errors should be emitted to stderr
+         */
+        unsigned emit_request_errors : 1;
+    } error_log;
+} h2o_pathconf_t;
+
+struct st_h2o_hostconf_t {
+    /**
+     * reverse reference to the global configuration
+     */
+    h2o_globalconf_t *global;
+    /**
+     * host and port
+     */
+    struct {
+        /**
+         * host and port (in lower-case; base is NULL-terminated)
+         */
+        h2o_iovec_t hostport;
+        /**
+         *  in lower-case; base is NULL-terminated
+         */
+        h2o_iovec_t host;
+        /**
+         * port number (or 65535 if default)
+         */
+        uint16_t port;
+    } authority;
+    /**
+     * list of path configurations
+     */
+    H2O_VECTOR(h2o_pathconf_t) paths;
+    /**
+     * catch-all path configuration
+     */
+    h2o_pathconf_t fallback_path;
+    /**
+     * mimemap
+     */
+    h2o_mimemap_t *mimemap;
+    /**
+     * http2
+     */
+    struct {
+        /**
+         * whether if blocking assets being pulled should be given highest priority in case of clients that do not implement
+         * dependency-based prioritization
+         */
+        unsigned reprioritize_blocking_assets : 1;
+        /**
+         * if server push should be used
+         */
+        unsigned push_preload : 1;
+        /**
+         * casper settings
+         */
+        h2o_casper_conf_t casper;
+    } http2;
+};
+
+typedef struct st_h2o_protocol_callbacks_t {
+    void (*request_shutdown)(h2o_context_t *ctx);
+    int (*foreach_request)(h2o_context_t *ctx, int (*cb)(h2o_req_t *req, void *cbdata), void *cbdata);
+} h2o_protocol_callbacks_t;
+
+typedef h2o_iovec_t (*final_status_handler_cb)(void *ctx, h2o_globalconf_t *gconf, h2o_req_t *req);
+typedef struct st_h2o_status_handler_t {
+    h2o_iovec_t name;
+    void *(*init)(void); /* optional callback, allocates a context that will be passed to per_thread() */
+    void (*per_thread)(void *priv, h2o_context_t *ctx); /* optional callback, will be called for each thread */
+    h2o_iovec_t (* final)(void *ctx, h2o_globalconf_t *gconf, h2o_req_t *req); /* mandatory, will be passed the optional context */
+} h2o_status_handler_t;
+
+typedef H2O_VECTOR(h2o_status_handler_t) h2o_status_callbacks_t;
+struct st_h2o_globalconf_t {
+    /**
+     * a NULL-terminated list of host contexts (h2o_hostconf_t)
+     */
+    h2o_hostconf_t **hosts;
+    /**
+     * list of configurators
+     */
+    h2o_linklist_t configurators;
+    /**
+     * name of the server (not the hostname)
+     */
+    h2o_iovec_t server_name;
+    /**
+     * maximum size of the accepted request entity (e.g. POST data)
+     */
+    size_t max_request_entity_size;
+    /**
+     * maximum count for delegations
+     */
+    unsigned max_delegations;
+    /**
+     * setuid user (or NULL)
+     */
+    char *user;
+
+    /**
+     * SSL handshake timeout
+     */
+    uint64_t handshake_timeout;
+
+    struct {
+        /**
+         * request timeout (in milliseconds)
+         */
+        uint64_t req_timeout;
+        /**
+         * a boolean value indicating whether or not to upgrade to HTTP/2
+         */
+        int upgrade_to_http2;
+        /**
+         * list of callbacks
+         */
+        h2o_protocol_callbacks_t callbacks;
+    } http1;
+
+    struct {
+        /**
+         * idle timeout (in milliseconds)
+         */
+        uint64_t idle_timeout;
+        /**
+         * graceful shutdown timeout (in milliseconds)
+         */
+        uint64_t graceful_shutdown_timeout;
+        /**
+         * maximum number of HTTP2 requests (per connection) to be handled simultaneously internally.
+         * H2O accepts at most 256 requests over HTTP/2, but internally limits the number of in-flight requests to the value
+         * specified by this property in order to limit the resources allocated to a single connection.
+         */
+        size_t max_concurrent_requests_per_connection;
+        /**
+         * maximum nuber of streams (per connection) to be allowed in IDLE / CLOSED state (used for tracking dependencies).
+         */
+        size_t max_streams_for_priority;
+        /**
+         * conditions for latency optimization
+         */
+        h2o_socket_latency_optimization_conditions_t latency_optimization;
+        /**
+         * list of callbacks
+         */
+        h2o_protocol_callbacks_t callbacks;
+    } http2;
+
+    struct {
+        /**
+         * io timeout (in milliseconds)
+         */
+        uint64_t io_timeout;
+        /**
+         * SSL context for connections initiated by the proxy (optional, governed by the application)
+         */
+        SSL_CTX *ssl_ctx;
+        /**
+         * a boolean flag if set to true, instructs the proxy to preserve the x-forwarded-proto header passed by the client
+         */
+        unsigned preserve_x_forwarded_proto : 1;
+        /**
+         * a boolean flag if set to true, instructs the proxy to preserve the server header passed by the origin
+         */
+        unsigned preserve_server_header : 1;
+        /**
+         * a boolean flag if set to true, instructs the proxy to emit x-forwarded-proto and x-forwarded-for headers
+         */
+        unsigned emit_x_forwarded_headers : 1;
+        /**
+         * a boolean flag if set to true, instructs the proxy to emit a via header
+         */
+        unsigned emit_via_header : 1;
+    } proxy;
+
+    /**
+     * mimemap
+     */
+    h2o_mimemap_t *mimemap;
+
+    /**
+     * filecache
+     */
+    struct {
+        /* capacity of the filecache */
+        size_t capacity;
+    } filecache;
+
+    /* status */
+    h2o_status_callbacks_t statuses;
+
+    size_t _num_config_slots;
+};
+
+enum {
+    H2O_COMPRESS_HINT_AUTO = 0, /* default: let h2o negociate compression based on the configuration */
+    H2O_COMPRESS_HINT_DISABLE,  /* compression was explicitely disabled for this request */
+    H2O_COMPRESS_HINT_ENABLE,   /* compression was explicitely enabled for this request */
+};
+
+/**
+ * holds various attributes related to the mime-type
+ */
+typedef struct st_h2o_mime_attributes_t {
+    /**
+     * whether if the content can be compressed by using gzip
+     */
+    char is_compressible;
+    /**
+     * how the resource should be prioritized
+     */
+    enum { H2O_MIME_ATTRIBUTE_PRIORITY_NORMAL = 0, H2O_MIME_ATTRIBUTE_PRIORITY_HIGHEST } priority;
+} h2o_mime_attributes_t;
+
+extern h2o_mime_attributes_t h2o_mime_attributes_as_is;
+
+/**
+ * represents either a mime-type (and associated info), or contains pathinfo in case of a dynamic type (e.g. .php files)
+ */
+typedef struct st_h2o_mimemap_type_t {
+    enum { H2O_MIMEMAP_TYPE_MIMETYPE = 0, H2O_MIMEMAP_TYPE_DYNAMIC = 1 } type;
+    union {
+        struct {
+            h2o_iovec_t mimetype;
+            h2o_mime_attributes_t attr;
+        };
+        struct {
+            h2o_pathconf_t pathconf;
+        } dynamic;
+    } data;
+} h2o_mimemap_type_t;
+
+/* defined as negated form of the error codes defined in HTTP2-spec section 7 */
+#define H2O_HTTP2_ERROR_NONE 0
+#define H2O_HTTP2_ERROR_PROTOCOL -1
+#define H2O_HTTP2_ERROR_INTERNAL -2
+#define H2O_HTTP2_ERROR_FLOW_CONTROL -3
+#define H2O_HTTP2_ERROR_SETTINGS_TIMEOUT -4
+#define H2O_HTTP2_ERROR_STREAM_CLOSED -5
+#define H2O_HTTP2_ERROR_FRAME_SIZE -6
+#define H2O_HTTP2_ERROR_REFUSED_STREAM -7
+#define H2O_HTTP2_ERROR_CANCEL -8
+#define H2O_HTTP2_ERROR_COMPRESSION -9
+#define H2O_HTTP2_ERROR_CONNECT -10
+#define H2O_HTTP2_ERROR_ENHANCE_YOUR_CALM -11
+#define H2O_HTTP2_ERROR_INADEQUATE_SECURITY -12
+#define H2O_HTTP2_ERROR_MAX 13
+/* end of the HTT2-spec defined errors */
+#define H2O_HTTP2_ERROR_INVALID_HEADER_CHAR                                                                                        \
+    -254 /* an internal value indicating that invalid characters were found in the header name or value */
+#define H2O_HTTP2_ERROR_INCOMPLETE -255 /* an internal value indicating that all data is not ready */
+#define H2O_HTTP2_ERROR_PROTOCOL_CLOSE_IMMEDIATELY -256
+
+enum {
+    /* http1 protocol errors */
+    H2O_STATUS_ERROR_400 = 0,
+    H2O_STATUS_ERROR_403,
+    H2O_STATUS_ERROR_404,
+    H2O_STATUS_ERROR_405,
+    H2O_STATUS_ERROR_413,
+    H2O_STATUS_ERROR_416,
+    H2O_STATUS_ERROR_417,
+    H2O_STATUS_ERROR_500,
+    H2O_STATUS_ERROR_502,
+    H2O_STATUS_ERROR_503,
+    H2O_STATUS_ERROR_MAX,
+};
+
+/**
+ * holds various data related to the context
+ */
+typedef struct st_h2o_context_storage_item_t {
+    void (*dispose)(void *data);
+    void *data;
+} h2o_context_storage_item_t;
+
+typedef H2O_VECTOR(h2o_context_storage_item_t) h2o_context_storage_t;
+
+/**
+ * context of the http server.
+ */
+struct st_h2o_context_t {
+    /**
+     * points to the loop (either uv_loop_t or h2o_evloop_t, depending on the value of H2O_USE_LIBUV)
+     */
+    h2o_loop_t *loop;
+    /**
+     * timeout structure to be used for registering deferred callbacks
+     */
+    h2o_timeout_t zero_timeout;
+    /**
+     * timeout structure to be used for registering 1-second timeout callbacks
+     */
+    h2o_timeout_t one_sec_timeout;
+    /**
+     * timeout structrue to be used for registering 100-milisecond timeout callbacks
+     */
+    h2o_timeout_t hundred_ms_timeout;
+    /**
+     * pointer to the global configuration
+     */
+    h2o_globalconf_t *globalconf;
+    /**
+     * queue for receiving messages from other contexts
+     */
+    h2o_multithread_queue_t *queue;
+    /**
+     * receivers
+     */
+    struct {
+        h2o_multithread_receiver_t hostinfo_getaddr;
+    } receivers;
+    /**
+     * open file cache
+     */
+    h2o_filecache_t *filecache;
+    /**
+     * context scope storage for general use
+     */
+    h2o_context_storage_t storage;
+    /**
+     * flag indicating if shutdown has been requested
+     */
+    int shutdown_requested;
+
+    /**
+     * SSL handshake timeout
+     */
+    h2o_timeout_t handshake_timeout;
+
+    struct {
+        /**
+         * request timeout
+         */
+        h2o_timeout_t req_timeout;
+        /**
+         * link-list of h2o_http1_conn_t
+         */
+        h2o_linklist_t _conns;
+    } http1;
+
+    struct {
+        /**
+         * idle timeout
+         */
+        h2o_timeout_t idle_timeout;
+        /**
+         * link-list of h2o_http2_conn_t
+         */
+        h2o_linklist_t _conns;
+        /**
+         * graceful shutdown timeout
+         */
+        h2o_timeout_t graceful_shutdown_timeout;
+        /**
+         * timeout entry used for graceful shutdown
+         */
+        h2o_timeout_entry_t _graceful_shutdown_timeout;
+        struct {
+            /**
+             * counter for http2 errors internally emitted by h2o
+             */
+            uint64_t protocol_level_errors[H2O_HTTP2_ERROR_MAX];
+            /**
+             * premature close on read
+             */
+            uint64_t read_closed;
+            /**
+             * premature close on write
+             */
+            uint64_t write_closed;
+        } events;
+    } http2;
+
+    struct {
+        /**
+         * the default client context for proxy
+         */
+        h2o_http1client_ctx_t client_ctx;
+        /**
+         * timeout handler used by the default client context
+         */
+        h2o_timeout_t io_timeout;
+    } proxy;
+
+    /**
+     * pointer to per-module configs
+     */
+    void **_module_configs;
+
+    struct {
+        uint64_t uv_now_at;
+        struct timeval tv_at;
+        h2o_timestamp_string_t *value;
+    } _timestamp_cache;
+
+    /**
+     * counter for http1 error status internally emitted by h2o
+     */
+    uint64_t emitted_error_status[H2O_STATUS_ERROR_MAX];
+
+    H2O_VECTOR(h2o_pathconf_t *) _pathconfs_inited;
+};
+
+/**
+ * represents a HTTP header
+ */
+typedef struct st_h2o_header_t {
+    /**
+     * name of the header (may point to h2o_token_t which is an optimized subclass of h2o_iovec_t)
+     */
+    h2o_iovec_t *name;
+    /**
+     * The name of the header as originally received from the client, same length as `name`
+     */
+    const char *orig_name;
+    /**
+     * value of the header
+     */
+    h2o_iovec_t value;
+} h2o_header_t;
+
+/**
+ * list of headers
+ */
+typedef H2O_VECTOR(h2o_header_t) h2o_headers_t;
+
+/**
+ * an object that generates a response.
+ * The object is typically constructed by handlers calling the h2o_start_response function.
+ */
+typedef struct st_h2o_generator_t {
+    /**
+     * called by the core to request new data to be pushed via the h2o_send function.
+     */
+    void (*proceed)(struct st_h2o_generator_t *self, h2o_req_t *req);
+    /**
+     * called by the core when there is a need to terminate the response abruptly
+     */
+    void (*stop)(struct st_h2o_generator_t *self, h2o_req_t *req);
+} h2o_generator_t;
+
+typedef enum h2o_send_state {
+    H2O_SEND_STATE_IN_PROGRESS,
+    H2O_SEND_STATE_FINAL,
+    H2O_SEND_STATE_ERROR,
+} h2o_send_state_t;
+
+typedef h2o_send_state_t (*h2o_ostream_pull_cb)(h2o_generator_t *generator, h2o_req_t *req, h2o_iovec_t *buf);
+
+static inline int h2o_send_state_is_in_progress(h2o_send_state_t s)
+{
+    return s == H2O_SEND_STATE_IN_PROGRESS;
+}
+/**
+ * an output stream that may alter the output.
+ * The object is typically constructed by filters calling the h2o_prepend_ostream function.
+ */
+struct st_h2o_ostream_t {
+    /**
+     * points to the next output stream
+     */
+    struct st_h2o_ostream_t *next;
+    /**
+     * called by the core to send output.
+     * Intermediary output streams should process the given output and call the h2o_ostream_send_next function if any data can be
+     * sent.
+     */
+    void (*do_send)(struct st_h2o_ostream_t *self, h2o_req_t *req, h2o_iovec_t *bufs, size_t bufcnt, h2o_send_state_t state);
+    /**
+     * called by the core when there is a need to terminate the response abruptly
+     */
+    void (*stop)(struct st_h2o_ostream_t *self, h2o_req_t *req);
+    /**
+     * whether if the ostream supports "pull" interface
+     */
+    void (*start_pull)(struct st_h2o_ostream_t *self, h2o_ostream_pull_cb cb);
+};
+
+/**
+ * a HTTP response
+ */
+typedef struct st_h2o_res_t {
+    /**
+     * status code
+     */
+    int status;
+    /**
+     * reason phrase
+     */
+    const char *reason;
+    /**
+     * length of the content (that is sent as the Content-Length header).
+     * The default value is SIZE_MAX, which means that the length is indeterminate.
+     * Generators should set this value whenever possible.
+     */
+    size_t content_length;
+    /**
+     * list of response headers
+     */
+    h2o_headers_t headers;
+    /**
+     * mime-related attributes (may be NULL)
+     */
+    h2o_mime_attributes_t *mime_attr;
+    /**
+     * retains the original response header before rewritten by ostream filters
+     */
+    struct {
+        int status;
+        h2o_headers_t headers;
+    } original;
+} h2o_res_t;
+
+/**
+ * debug state (currently only for HTTP/2)
+ */
+typedef struct st_h2o_http2_debug_state_t {
+    h2o_iovec_vector_t json;
+    ssize_t conn_flow_in;
+    ssize_t conn_flow_out;
+} h2o_http2_debug_state_t;
+
+typedef struct st_h2o_conn_callbacks_t {
+    /**
+     * getsockname (return size of the obtained address, or 0 if failed)
+     */
+    socklen_t (*get_sockname)(h2o_conn_t *conn, struct sockaddr *sa);
+    /**
+     * getpeername (return size of the obtained address, or 0 if failed)
+     */
+    socklen_t (*get_peername)(h2o_conn_t *conn, struct sockaddr *sa);
+    /**
+     * callback for server push (may be NULL)
+     */
+    void (*push_path)(h2o_req_t *req, const char *abspath, size_t abspath_len);
+    /**
+     * Return the underlying socket struct
+     */
+    h2o_socket_t *(*get_socket)(h2o_conn_t *_conn);
+    /**
+     * debug state callback (may be NULL)
+     */
+    h2o_http2_debug_state_t *(*get_debug_state)(h2o_req_t *req, int hpack_enabled);
+    /**
+     * logging callbacks (may be NULL)
+     */
+    union {
+        struct {
+            struct {
+                h2o_iovec_t (*protocol_version)(h2o_req_t *req);
+                h2o_iovec_t (*session_reused)(h2o_req_t *req);
+                h2o_iovec_t (*cipher)(h2o_req_t *req);
+                h2o_iovec_t (*cipher_bits)(h2o_req_t *req);
+                h2o_iovec_t (*session_id)(h2o_req_t *req);
+            } ssl;
+            struct {
+                h2o_iovec_t (*request_index)(h2o_req_t *req);
+            } http1;
+            struct {
+                h2o_iovec_t (*stream_id)(h2o_req_t *req);
+                h2o_iovec_t (*priority_received)(h2o_req_t *req);
+                h2o_iovec_t (*priority_received_exclusive)(h2o_req_t *req);
+                h2o_iovec_t (*priority_received_parent)(h2o_req_t *req);
+                h2o_iovec_t (*priority_received_weight)(h2o_req_t *req);
+                h2o_iovec_t (*priority_actual)(h2o_req_t *req);
+                h2o_iovec_t (*priority_actual_parent)(h2o_req_t *req);
+                h2o_iovec_t (*priority_actual_weight)(h2o_req_t *req);
+            } http2;
+        };
+        h2o_iovec_t (*callbacks[1])(h2o_req_t *req);
+    } log_;
+} h2o_conn_callbacks_t;
+
+/**
+ * basic structure of an HTTP connection (HTTP/1, HTTP/2, etc.)
+ */
+struct st_h2o_conn_t {
+    /**
+     * the context of the server
+     */
+    h2o_context_t *ctx;
+    /**
+     * NULL-terminated list of hostconfs bound to the connection
+     */
+    h2o_hostconf_t **hosts;
+    /**
+     * time when the connection was established
+     */
+    struct timeval connected_at;
+    /**
+     * connection id
+     */
+    uint64_t id;
+    /**
+     * callbacks
+     */
+    const h2o_conn_callbacks_t *callbacks;
+};
+
+/**
+ * filter used for capturing a response (can be used to implement subreq)
+ */
+typedef struct st_h2o_req_prefilter_t {
+    struct st_h2o_req_prefilter_t *next;
+    void (*on_setup_ostream)(struct st_h2o_req_prefilter_t *self, h2o_req_t *req, h2o_ostream_t **slot);
+} h2o_req_prefilter_t;
+
+typedef struct st_h2o_req_overrides_t {
+    /**
+     * specific client context (or NULL)
+     */
+    h2o_http1client_ctx_t *client_ctx;
+    /**
+     * socketpool to be used when connecting to upstream (or NULL)
+     */
+    h2o_socketpool_t *socketpool;
+    /**
+     * upstream host:port to connect to (or host.base == NULL)
+     */
+    struct {
+        h2o_iovec_t host;
+        uint16_t port;
+    } hostport;
+    /**
+     * parameters for rewriting the `Location` header (only used if match.len != 0)
+     */
+    struct {
+        /**
+         * if the prefix of the location header matches the url, then the header will be rewritten
+         */
+        h2o_url_t *match;
+        /**
+         * path prefix to be inserted upon rewrite
+         */
+        h2o_iovec_t path_prefix;
+    } location_rewrite;
+    /**
+     * whether if the PROXY header should be sent
+     */
+    unsigned use_proxy_protocol : 1;
+    /**
+     * headers rewrite commands to be used when sending requests to upstream (or NULL)
+     */
+    h2o_headers_command_t *headers_cmds;
+} h2o_req_overrides_t;
+
+/**
+ * additional information for extension-based dynamic content
+ */
+typedef struct st_h2o_filereq_t {
+    h2o_iovec_t script_name;
+    h2o_iovec_t path_info;
+    h2o_iovec_t local_path;
+} h2o_filereq_t;
+
+/**
+ * error message associated to a request
+ */
+typedef struct st_h2o_req_error_log_t {
+    const char *module;
+    h2o_iovec_t msg;
+} h2o_req_error_log_t;
+
+/**
+ * a HTTP request
+ */
+struct st_h2o_req_t {
+    /**
+     * the underlying connection
+     */
+    h2o_conn_t *conn;
+    /**
+     * the request sent by the client (as is)
+     */
+    struct {
+        /**
+         * scheme (http, https, etc.)
+         */
+        const h2o_url_scheme_t *scheme;
+        /**
+         * authority (a.k.a. the Host header; the value is supplemented if missing before the handlers are being called)
+         */
+        h2o_iovec_t authority;
+        /**
+         * method
+         */
+        h2o_iovec_t method;
+        /**
+         * abs-path of the request (unmodified)
+         */
+        h2o_iovec_t path;
+        /**
+         * offset of '?' within path, or SIZE_MAX if not found
+         */
+        size_t query_at;
+    } input;
+    /**
+     * the host context
+     */
+    h2o_hostconf_t *hostconf;
+    /**
+     * the path context
+     */
+    h2o_pathconf_t *pathconf;
+    /**
+     * scheme (http, https, etc.)
+     */
+    const h2o_url_scheme_t *scheme;
+    /**
+     * authority (of the processing request)
+     */
+    h2o_iovec_t authority;
+    /**
+     * method (of the processing request)
+     */
+    h2o_iovec_t method;
+    /**
+     * abs-path of the processing request
+     */
+    h2o_iovec_t path;
+    /**
+     * offset of '?' within path, or SIZE_MAX if not found
+     */
+    size_t query_at;
+    /**
+     * normalized path of the processing request (i.e. no "." or "..", no query)
+     */
+    h2o_iovec_t path_normalized;
+    /**
+     * Map of indexes of `path_normalized` into the next character in `path`; built only if `path` required normalization
+     */
+    size_t *norm_indexes;
+    /**
+     * filters assigned per request
+     */
+    h2o_req_prefilter_t *prefilters;
+    /**
+     * additional information (becomes available for extension-based dynamic content)
+     */
+    h2o_filereq_t *filereq;
+    /**
+     * overrides (maybe NULL)
+     */
+    h2o_req_overrides_t *overrides;
+    /**
+     * the HTTP version (represented as 0xMMmm (M=major, m=minor))
+     */
+    int version;
+    /**
+     * list of request headers
+     */
+    h2o_headers_t headers;
+    /**
+     * the request entity (base == NULL if none)
+     */
+    h2o_iovec_t entity;
+    /**
+     * timestamp when the request was processed
+     */
+    h2o_timestamp_t processed_at;
+    /**
+     * additional timestamps
+     */
+    struct {
+        struct timeval request_begin_at;
+        struct timeval request_body_begin_at;
+        struct timeval response_start_at;
+        struct timeval response_end_at;
+    } timestamps;
+    /**
+     * the response
+     */
+    h2o_res_t res;
+    /**
+     * number of bytes sent by the generator (excluding headers)
+     */
+    size_t bytes_sent;
+    /**
+     * counts the number of times the request has been reprocessed (excluding delegation)
+     */
+    unsigned num_reprocessed;
+    /**
+     * counts the number of times the request has been delegated
+     */
+    unsigned num_delegated;
+
+    /**
+     * environment variables
+     */
+    h2o_iovec_vector_t env;
+
+    /**
+     * error logs
+     */
+    H2O_VECTOR(h2o_req_error_log_t) error_logs;
+
+    /* flags */
+
+    /**
+     * whether or not the connection is persistent.
+     * Applications should set this flag to zero in case the connection cannot be kept keep-alive (due to an error etc.)
+     */
+    unsigned char http1_is_persistent : 1;
+    /**
+     * whether if the response has been delegated (i.e. reproxied).
+     * For delegated responses, redirect responses would be handled internally.
+     */
+    unsigned char res_is_delegated : 1;
+    /**
+     * whether if the bytes sent is counted by ostreams other than final ostream
+     */
+    unsigned char bytes_counted_by_ostream : 1;
+
+    /**
+     * Whether the producer of the response has explicitely disabled or
+     * enabled compression. One of H2O_COMPRESS_HINT_*
+     */
+    char compress_hint;
+
+    /**
+     * the Upgrade request header (or { NULL, 0 } if not available)
+     */
+    h2o_iovec_t upgrade;
+
+    /**
+     * preferred chunk size by the ostream
+     */
+    size_t preferred_chunk_size;
+
+    /* internal structure */
+    h2o_generator_t *_generator;
+    h2o_ostream_t *_ostr_top;
+    size_t _next_filter_index;
+    h2o_timeout_entry_t _timeout_entry;
+    /* per-request memory pool (placed at the last since the structure is large) */
+    h2o_mem_pool_t pool;
+};
+
+typedef struct st_h2o_accept_ctx_t {
+    h2o_context_t *ctx;
+    h2o_hostconf_t **hosts;
+    SSL_CTX *ssl_ctx;
+    int expect_proxy_line;
+    h2o_multithread_receiver_t *libmemcached_receiver;
+} h2o_accept_ctx_t;
+
+typedef struct st_h2o_doublebuffer_t {
+    h2o_buffer_t *buf;
+    size_t bytes_inflight;
+} h2o_doublebuffer_t;
+
+static void h2o_doublebuffer_init(h2o_doublebuffer_t *db, h2o_buffer_prototype_t *prototype);
+static void h2o_doublebuffer_dispose(h2o_doublebuffer_t *db);
+static h2o_iovec_t h2o_doublebuffer_prepare(h2o_doublebuffer_t *db, h2o_buffer_t **receiving, size_t max_bytes);
+static void h2o_doublebuffer_consume(h2o_doublebuffer_t *db);
+
+/* token */
+
+extern h2o_token_t h2o__tokens[H2O_MAX_TOKENS];
+extern size_t h2o__num_tokens;
+
+/**
+ * returns a token (an optimized subclass of h2o_iovec_t) containing given string, or NULL if no such thing is available
+ */
+const h2o_token_t *h2o_lookup_token(const char *name, size_t len);
+/**
+ * returns an boolean value if given buffer is a h2o_token_t.
+ */
+int h2o_iovec_is_token(const h2o_iovec_t *buf);
+
+/* headers */
+
+/**
+ * searches for a header of given name (fast, by comparing tokens)
+ * @param headers header list
+ * @param token name of the header to search for
+ * @param cursor index of the last match (or set SIZE_MAX to start a new search)
+ * @return index of the found header (or SIZE_MAX if not found)
+ */
+ssize_t h2o_find_header(const h2o_headers_t *headers, const h2o_token_t *token, ssize_t cursor);
+/**
+ * searches for a header of given name (slow, by comparing strings)
+ * @param headers header list
+ * @param name name of the header to search for
+ * @param name_len length of the name
+ * @param cursor index of the last match (or set SIZE_MAX to start a new search)
+ * @return index of the found header (or SIZE_MAX if not found)
+ */
+ssize_t h2o_find_header_by_str(const h2o_headers_t *headers, const char *name, size_t name_len, ssize_t cursor);
+/**
+ * adds a header to list
+ */
+void h2o_add_header(h2o_mem_pool_t *pool, h2o_headers_t *headers, const h2o_token_t *token, const char *orig_name,
+                    const char *value, size_t value_len);
+/**
+ * adds a header to list
+ */
+void h2o_add_header_by_str(h2o_mem_pool_t *pool, h2o_headers_t *headers, const char *name, size_t name_len, int maybe_token,
+                           const char *orig_name, const char *value, size_t value_len);
+/**
+ * adds or replaces a header into the list
+ */
+void h2o_set_header(h2o_mem_pool_t *pool, h2o_headers_t *headers, const h2o_token_t *token, const char *value, size_t value_len,
+                    int overwrite_if_exists);
+/**
+ * adds or replaces a header into the list
+ */
+void h2o_set_header_by_str(h2o_mem_pool_t *pool, h2o_headers_t *headers, const char *name, size_t name_len, int maybe_token,
+                           const char *value, size_t value_len, int overwrite_if_exists);
+/**
+ * sets a header token
+ */
+void h2o_set_header_token(h2o_mem_pool_t *pool, h2o_headers_t *headers, const h2o_token_t *token, const char *value,
+                          size_t value_len);
+/**
+ * deletes a header from list
+ */
+ssize_t h2o_delete_header(h2o_headers_t *headers, ssize_t cursor);
+
+/* util */
+
+extern const char *h2o_http2_npn_protocols;
+extern const char *h2o_npn_protocols;
+extern const h2o_iovec_t *h2o_http2_alpn_protocols;
+extern const h2o_iovec_t *h2o_alpn_protocols;
+
+/**
+ * accepts a connection
+ */
+void h2o_accept(h2o_accept_ctx_t *ctx, h2o_socket_t *sock);
+/**
+ * creates a new connection
+ */
+static h2o_conn_t *h2o_create_connection(size_t sz, h2o_context_t *ctx, h2o_hostconf_t **hosts, struct timeval connected_at,
+                                         const h2o_conn_callbacks_t *callbacks);
+/**
+ * setups accept context for async SSL resumption
+ */
+void h2o_accept_setup_async_ssl_resumption(h2o_memcached_context_t *ctx, unsigned expiration);
+/**
+ * returns the protocol version (e.g. "HTTP/1.1", "HTTP/2")
+ */
+size_t h2o_stringify_protocol_version(char *dst, int version);
+/**
+ * builds the proxy header defined by the PROXY PROTOCOL
+ */
+size_t h2o_stringify_proxy_header(h2o_conn_t *conn, char *buf);
+#define H2O_PROXY_HEADER_MAX_LENGTH                                                                                                \
+    (sizeof("PROXY TCP6 ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff 65535 65535\r\n") - 1)
+/**
+ * extracts path to be pushed from `Link: rel=preload` header, duplicating the chunk (or returns {NULL,0} if none)
+ */
+h2o_iovec_vector_t h2o_extract_push_path_from_link_header(h2o_mem_pool_t *pool, const char *value, size_t value_len,
+                                                          h2o_iovec_t base_path, const h2o_url_scheme_t *input_scheme,
+                                                          h2o_iovec_t input_authority, const h2o_url_scheme_t *base_scheme,
+                                                          h2o_iovec_t *base_authority, h2o_iovec_t *filtered_value);
+/**
+ * return a bitmap of compressible types, by parsing the `accept-encoding` header
+ */
+int h2o_get_compressible_types(const h2o_headers_t *headers);
+#define H2O_COMPRESSIBLE_GZIP 1
+#define H2O_COMPRESSIBLE_BROTLI 2
+/**
+ * builds destination URL or path, by contatenating the prefix and path_info of the request
+ */
+h2o_iovec_t h2o_build_destination(h2o_req_t *req, const char *prefix, size_t prefix_len, int use_path_normalized);
+
+extern uint64_t h2o_connection_id;
+
+/* request */
+
+/**
+ * initializes the request structure
+ * @param req the request structure
+ * @param conn the underlying connection
+ * @param src if not NULL, the request structure would be a shallow copy of src
+ */
+void h2o_init_request(h2o_req_t *req, h2o_conn_t *conn, h2o_req_t *src);
+/**
+ * releases resources allocated for handling a request
+ */
+void h2o_dispose_request(h2o_req_t *req);
+/**
+ * called by the connection layer to start processing a request that is ready
+ */
+void h2o_process_request(h2o_req_t *req);
+/**
+ * delegates the request to the next handler; called asynchronously by handlers that returned zero from `on_req`
+ */
+void h2o_delegate_request(h2o_req_t *req, h2o_handler_t *current_handler);
+/**
+ * calls h2o_delegate_request using zero_timeout callback
+ */
+void h2o_delegate_request_deferred(h2o_req_t *req, h2o_handler_t *current_handler);
+/**
+ * reprocesses a request once more (used for internal redirection)
+ */
+void h2o_reprocess_request(h2o_req_t *req, h2o_iovec_t method, const h2o_url_scheme_t *scheme, h2o_iovec_t authority,
+                           h2o_iovec_t path, h2o_req_overrides_t *overrides, int is_delegated);
+/**
+ * calls h2o_reprocess_request using zero_timeout callback
+ */
+void h2o_reprocess_request_deferred(h2o_req_t *req, h2o_iovec_t method, const h2o_url_scheme_t *scheme, h2o_iovec_t authority,
+                                    h2o_iovec_t path, h2o_req_overrides_t *overrides, int is_delegated);
+/**
+ * called by handlers to set the generator
+ * @param req the request
+ * @param generator the generator
+ */
+void h2o_start_response(h2o_req_t *req, h2o_generator_t *generator);
+/**
+ * called by filters to insert output-stream filters for modifying the response
+ * @param req the request
+ * @param size of the memory to be allocated for the ostream filter
+ * @param slot where the stream should be inserted
+ * @return pointer to the ostream filter
+ */
+h2o_ostream_t *h2o_add_ostream(h2o_req_t *req, size_t sz, h2o_ostream_t **slot);
+/**
+ * binds configurations to the request
+ */
+void h2o_req_bind_conf(h2o_req_t *req, h2o_hostconf_t *hostconf, h2o_pathconf_t *pathconf);
+
+/**
+ * called by the generators to send output
+ * note: generators should free itself after sending the final chunk (i.e. calling the function with is_final set to true)
+ * @param req the request
+ * @param bufs an array of buffers
+ * @param bufcnt length of the buffers array
+ * @param state describes if the output is final, has an error, or is in progress
+ */
+void h2o_send(h2o_req_t *req, h2o_iovec_t *bufs, size_t bufcnt, h2o_send_state_t state);
+/**
+ * called by the connection layer to pull the content from generator (if pull mode is being used)
+ */
+static h2o_send_state_t h2o_pull(h2o_req_t *req, h2o_ostream_pull_cb cb, h2o_iovec_t *buf);
+/**
+ * creates an uninitialized prefilter and returns pointer to it
+ */
+h2o_req_prefilter_t *h2o_add_prefilter(h2o_req_t *req, size_t sz);
+/**
+ * requests the next prefilter or filter (if any) to setup the ostream if necessary
+ */
+static void h2o_setup_next_prefilter(h2o_req_prefilter_t *self, h2o_req_t *req, h2o_ostream_t **slot);
+/**
+ * requests the next filter (if any) to setup the ostream if necessary
+ */
+static void h2o_setup_next_ostream(h2o_req_t *req, h2o_ostream_t **slot);
+/**
+ * called by the ostream filters to send output to the next ostream filter
+ * note: ostream filters should free itself after sending the final chunk (i.e. calling the function with is_final set to true)
+ * note: ostream filters must not set is_final flag to TRUE unless is_final flag of the do_send callback was set as such
+ * @param ostr current ostream filter
+ * @param req the request
+ * @param bufs an array of buffers
+ * @param bufcnt length of the buffers array
+ * @param state whether the output is in progress, final, or in error
+ */
+void h2o_ostream_send_next(h2o_ostream_t *ostream, h2o_req_t *req, h2o_iovec_t *bufs, size_t bufcnt, h2o_send_state_t state);
+/**
+ * called by the connection layer to request additional data to the generator
+ */
+static void h2o_proceed_response(h2o_req_t *req);
+/**
+ * if NULL, supplements h2o_req_t::mime_attr
+ */
+void h2o_req_fill_mime_attributes(h2o_req_t *req);
+/**
+ * returns an environment variable
+ */
+static h2o_iovec_t *h2o_req_getenv(h2o_req_t *req, const char *name, size_t name_len, int allocate_if_not_found);
+/**
+ * unsets an environment variable
+ */
+static void h2o_req_unsetenv(h2o_req_t *req, const char *name, size_t name_len);
+
+/* config */
+
+h2o_envconf_t *h2o_config_create_envconf(h2o_envconf_t *src);
+void h2o_config_setenv(h2o_envconf_t *envconf, const char *name, const char *value);
+void h2o_config_unsetenv(h2o_envconf_t *envconf, const char *name);
+
+/**
+ * initializes pathconf
+ * @param path path to serve, or NULL if fallback or extension-level
+ * @param mimemap mimemap to use, or NULL if fallback or extension-level
+ */
+void h2o_config_init_pathconf(h2o_pathconf_t *pathconf, h2o_globalconf_t *globalconf, const char *path, h2o_mimemap_t *mimemap);
+/**
+ *
+ */
+void h2o_config_dispose_pathconf(h2o_pathconf_t *pathconf);
+/**
+ * initializes the global configuration
+ */
+void h2o_config_init(h2o_globalconf_t *config);
+/**
+ * registers a host context
+ */
+h2o_hostconf_t *h2o_config_register_host(h2o_globalconf_t *config, h2o_iovec_t host, uint16_t port);
+/**
+ * registers a path context
+ * @param hostconf host-level configuration that the path-level configuration belongs to
+ * @param path path
+ * @param flags unused and must be set to zero
+ *
+ * Handling of the path argument has changed in version 2.0 (of the standard server).
+ *
+ * Before 2.0, the function implicitely added a trailing `/` to the supplied path (if it did not end with a `/`), and when receiving
+ * a HTTP request for a matching path without the trailing `/`, libh2o sent a 301 response redirecting the client to a URI with a
+ * trailing `/`.
+ *
+ * Since 2.0, the function retains the exact path given as the argument, and the handlers of the pathconf is invoked if one of the
+ * following conditions are met:
+ *
+ * * request path is an exact match to the configuration path
+ * * configuration path does not end with a `/`, and the request path begins with the configuration path followed by a `/`
+ */
+h2o_pathconf_t *h2o_config_register_path(h2o_hostconf_t *hostconf, const char *path, int flags);
+/**
+ * registers an extra status handler
+ */
+void h2o_config_register_status_handler(h2o_globalconf_t *config, h2o_status_handler_t);
+void h2o_config_register_simple_status_handler(h2o_globalconf_t *config, h2o_iovec_t name, final_status_handler_cb status_handler);
+/**
+ * disposes of the resources allocated for the global configuration
+ */
+void h2o_config_dispose(h2o_globalconf_t *config);
+/**
+ * creates a handler associated to a given pathconf
+ */
+h2o_handler_t *h2o_create_handler(h2o_pathconf_t *conf, size_t sz);
+/**
+ * creates a filter associated to a given pathconf
+ */
+h2o_filter_t *h2o_create_filter(h2o_pathconf_t *conf, size_t sz);
+/**
+ * creates a logger associated to a given pathconf
+ */
+h2o_logger_t *h2o_create_logger(h2o_pathconf_t *conf, size_t sz);
+
+/* context */
+
+/**
+ * initializes the context
+ */
+void h2o_context_init(h2o_context_t *context, h2o_loop_t *loop, h2o_globalconf_t *config);
+/**
+ * disposes of the resources allocated for the context
+ */
+void h2o_context_dispose(h2o_context_t *context);
+/**
+ * requests shutdown to the connections governed by the context
+ */
+void h2o_context_request_shutdown(h2o_context_t *context);
+/**
+ *
+ */
+void h2o_context_init_pathconf_context(h2o_context_t *ctx, h2o_pathconf_t *pathconf);
+/**
+ *
+ */
+void h2o_context_dispose_pathconf_context(h2o_context_t *ctx, h2o_pathconf_t *pathconf);
+/**
+ * returns current timestamp
+ * @param ctx the context
+ * @param pool memory pool (used when ts != NULL)
+ * @param ts buffer to store the timestamp (optional)
+ * @return current time in UTC
+ */
+static struct timeval *h2o_get_timestamp(h2o_context_t *ctx, h2o_mem_pool_t *pool, h2o_timestamp_t *ts);
+void h2o_context_update_timestamp_cache(h2o_context_t *ctx);
+/**
+ * returns per-module context set
+ */
+static void *h2o_context_get_handler_context(h2o_context_t *ctx, h2o_handler_t *handler);
+/**
+ * sets per-module context
+ */
+static void h2o_context_set_handler_context(h2o_context_t *ctx, h2o_handler_t *handler, void *handler_ctx);
+/**
+ * returns per-module context set by the on_context_init callback
+ */
+static void *h2o_context_get_filter_context(h2o_context_t *ctx, h2o_filter_t *filter);
+/**
+ * sets per-module filter context
+ */
+static void h2o_context_set_filter_context(h2o_context_t *ctx, h2o_filter_t *filter, void *filter_ctx);
+/**
+ * returns per-module context set by the on_context_init callback
+ */
+static void *h2o_context_get_logger_context(h2o_context_t *ctx, h2o_logger_t *logger);
+/*
+ * return the address associated with the key in the context storage
+ */
+static void **h2o_context_get_storage(h2o_context_t *ctx, size_t *key, void (*dispose_cb)(void *));
+
+/* built-in generators */
+
+enum {
+    /**
+     * enforces the http1 protocol handler to close the connection after sending the response
+     */
+    H2O_SEND_ERROR_HTTP1_CLOSE_CONNECTION = 0x1,
+    /**
+     * if set, does not flush the registered response headers
+     */
+    H2O_SEND_ERROR_KEEP_HEADERS = 0x2
+};
+
+/**
+ * sends the given string as the response
+ */
+void h2o_send_inline(h2o_req_t *req, const char *body, size_t len);
+/**
+ * sends the given information as an error response to the client
+ */
+void h2o_send_error_generic(h2o_req_t *req, int status, const char *reason, const char *body, int flags);
+#define H2O_SEND_ERROR_XXX(status)                                                                                                 \
+    static inline void h2o_send_error_##status(h2o_req_t *req, const char *reason, const char *body, int flags)                    \
+    {                                                                                                                              \
+        req->conn->ctx->emitted_error_status[H2O_STATUS_ERROR_##status]++;                                                         \
+        h2o_send_error_generic(req, status, reason, body, flags);                                                                  \
+    }
+
+H2O_SEND_ERROR_XXX(400)
+H2O_SEND_ERROR_XXX(403)
+H2O_SEND_ERROR_XXX(404)
+H2O_SEND_ERROR_XXX(405)
+H2O_SEND_ERROR_XXX(416)
+H2O_SEND_ERROR_XXX(417)
+H2O_SEND_ERROR_XXX(500)
+H2O_SEND_ERROR_XXX(502)
+H2O_SEND_ERROR_XXX(503)
+
+/**
+ * sends error response using zero timeout; can be called by output filters while processing the headers
+ */
+void h2o_send_error_deferred(h2o_req_t *req, int status, const char *reason, const char *body, int flags);
+/**
+ * sends a redirect response
+ */
+void h2o_send_redirect(h2o_req_t *req, int status, const char *reason, const char *url, size_t url_len);
+/**
+ * handles redirect internally
+ */
+void h2o_send_redirect_internal(h2o_req_t *req, h2o_iovec_t method, const char *url_str, size_t url_len, int preserve_overrides);
+/**
+ * returns method to be used after redirection
+ */
+h2o_iovec_t h2o_get_redirect_method(h2o_iovec_t method, int status);
+/**
+ * registers push path (if necessary) by parsing a Link header
+ * this returns a version of `value` that removes the links that had the `x-http2-push-only` attribute
+ */
+h2o_iovec_t h2o_push_path_in_link_header(h2o_req_t *req, const char *value, size_t value_len);
+/**
+ * logs an error
+ */
+void h2o_req_log_error(h2o_req_t *req, const char *module, const char *fmt, ...) __attribute__((format(printf, 3, 4)));
+
+/* log */
+
+enum { H2O_LOGCONF_ESCAPE_APACHE, H2O_LOGCONF_ESCAPE_JSON };
+
+/**
+ * compiles a log configuration
+ */
+h2o_logconf_t *h2o_logconf_compile(const char *fmt, int escape, char *errbuf);
+/**
+ * disposes of a log configuration
+ */
+void h2o_logconf_dispose(h2o_logconf_t *logconf);
+/**
+ * logs a request
+ */
+char *h2o_log_request(h2o_logconf_t *logconf, h2o_req_t *req, size_t *len, char *buf);
+
+/* proxy */
+
+/**
+ * processes a request (by sending the request upstream)
+ */
+void h2o__proxy_process_request(h2o_req_t *req);
+
+/* mime mapper */
+
+/**
+ * initializes the mimemap (the returned chunk is refcounted)
+ */
+h2o_mimemap_t *h2o_mimemap_create(void);
+/**
+ * clones a mimemap
+ */
+h2o_mimemap_t *h2o_mimemap_clone(h2o_mimemap_t *src);
+/**
+ *
+ */
+void h2o_mimemap_on_context_init(h2o_mimemap_t *mimemap, h2o_context_t *ctx);
+/**
+ *
+ */
+void h2o_mimemap_on_context_dispose(h2o_mimemap_t *mimemap, h2o_context_t *ctx);
+/**
+ * returns if the map contains a dynamic type
+ */
+int h2o_mimemap_has_dynamic_type(h2o_mimemap_t *mimemap);
+/**
+ * sets the default mime-type
+ */
+void h2o_mimemap_set_default_type(h2o_mimemap_t *mimemap, const char *mime, h2o_mime_attributes_t *attr);
+/**
+ * adds a mime-type mapping
+ */
+void h2o_mimemap_define_mimetype(h2o_mimemap_t *mimemap, const char *ext, const char *mime, h2o_mime_attributes_t *attr);
+/**
+ * adds a mime-type mapping
+ */
+h2o_mimemap_type_t *h2o_mimemap_define_dynamic(h2o_mimemap_t *mimemap, const char **exts, h2o_globalconf_t *globalconf);
+/**
+ * removes a mime-type mapping
+ */
+void h2o_mimemap_remove_type(h2o_mimemap_t *mimemap, const char *ext);
+/**
+ * clears all mime-type mapping
+ */
+void h2o_mimemap_clear_types(h2o_mimemap_t *mimemap);
+/**
+ * sets the default mime-type
+ */
+h2o_mimemap_type_t *h2o_mimemap_get_default_type(h2o_mimemap_t *mimemap);
+/**
+ * returns the mime-type corresponding to given extension
+ */
+h2o_mimemap_type_t *h2o_mimemap_get_type_by_extension(h2o_mimemap_t *mimemap, h2o_iovec_t ext);
+/**
+ * returns the mime-type corresponding to given mimetype
+ */
+h2o_mimemap_type_t *h2o_mimemap_get_type_by_mimetype(h2o_mimemap_t *mimemap, h2o_iovec_t mime, int exact_match_only);
+/**
+ * returns the default mime attributes given a mime type
+ */
+void h2o_mimemap_get_default_attributes(const char *mime, h2o_mime_attributes_t *attr);
+
+/* various handlers */
+
+/* lib/access_log.c */
+
+typedef struct st_h2o_access_log_filehandle_t h2o_access_log_filehandle_t;
+
+int h2o_access_log_open_log(const char *path);
+h2o_access_log_filehandle_t *h2o_access_log_open_handle(const char *path, const char *fmt, int escape);
+h2o_logger_t *h2o_access_log_register(h2o_pathconf_t *pathconf, h2o_access_log_filehandle_t *handle);
+void h2o_access_log_register_configurator(h2o_globalconf_t *conf);
+
+/* lib/chunked.c */
+
+/**
+ * registers the chunked encoding output filter (added by default)
+ */
+void h2o_chunked_register(h2o_pathconf_t *pathconf);
+
+/* lib/compress.c */
+
+enum { H2O_COMPRESS_FLAG_PARTIAL, H2O_COMPRESS_FLAG_FLUSH, H2O_COMPRESS_FLAG_EOS };
+
+/**
+ * compressor context
+ */
+typedef struct st_h2o_compress_context_t {
+    /**
+     * name used in content-encoding header
+     */
+    h2o_iovec_t name;
+    /**
+     * compress or decompress callback
+     */
+    void (*transform)(struct st_h2o_compress_context_t *self, h2o_iovec_t *inbufs, size_t inbufcnt, h2o_send_state_t state,
+                      h2o_iovec_t **outbufs, size_t *outbufcnt);
+} h2o_compress_context_t;
+
+typedef struct st_h2o_compress_args_t {
+    size_t min_size;
+    struct {
+        int quality; /* -1 if disabled */
+    } gzip;
+    struct {
+        int quality; /* -1 if disabled */
+    } brotli;
+} h2o_compress_args_t;
+
+/**
+ * registers the gzip/brotli encoding output filter (added by default, for now)
+ */
+void h2o_compress_register(h2o_pathconf_t *pathconf, h2o_compress_args_t *args);
+/**
+ * instantiates the gzip compressor
+ */
+h2o_compress_context_t *h2o_compress_gzip_open(h2o_mem_pool_t *pool, int quality);
+/**
+ * instantiates the gzip decompressor
+ */
+h2o_compress_context_t *h2o_compress_gunzip_open(h2o_mem_pool_t *pool);
+/**
+ * instantiates the brotli compressor (only available if H2O_USE_BROTLI is set)
+ */
+h2o_compress_context_t *h2o_compress_brotli_open(h2o_mem_pool_t *pool, int quality, size_t estimated_cotent_length);
+/**
+ * registers the configurator for the gzip/brotli output filter
+ */
+void h2o_compress_register_configurator(h2o_globalconf_t *conf);
+
+/* lib/handler/throttle_resp.c */
+/**
+ * registers the throttle response filter
+ */
+void h2o_throttle_resp_register(h2o_pathconf_t *pathconf);
+/**
+ * configurator
+ */
+void h2o_throttle_resp_register_configurator(h2o_globalconf_t *conf);
+
+/* lib/errordoc.c */
+
+typedef struct st_h2o_errordoc_t {
+    int status;
+    h2o_iovec_t url; /* can be relative */
+} h2o_errordoc_t;
+
+/**
+ * registers the errordocument output filter
+ */
+void h2o_errordoc_register(h2o_pathconf_t *pathconf, h2o_errordoc_t *errdocs, size_t cnt);
+/**
+ *
+ */
+void h2o_errordoc_register_configurator(h2o_globalconf_t *conf);
+
+/* lib/expires.c */
+
+enum { H2O_EXPIRES_MODE_ABSOLUTE, H2O_EXPIRES_MODE_MAX_AGE };
+
+typedef struct st_h2o_expires_args_t {
+    int mode;
+    union {
+        const char *absolute;
+        uint64_t max_age;
+    } data;
+} h2o_expires_args_t;
+
+/**
+ * registers a filter that adds an Expires (or Cache-Control) header
+ */
+void h2o_expires_register(h2o_pathconf_t *pathconf, h2o_expires_args_t *args);
+/**
+ *
+ */
+void h2o_expires_register_configurator(h2o_globalconf_t *conf);
+
+/* lib/fastcgi.c */
+
+typedef struct st_h2o_fastcgi_handler_t h2o_fastcgi_handler_t;
+
+#define H2O_DEFAULT_FASTCGI_IO_TIMEOUT 30000
+
+typedef struct st_h2o_fastcgi_config_vars_t {
+    uint64_t io_timeout;
+    uint64_t keepalive_timeout; /* 0 to disable */
+    h2o_iovec_t document_root;  /* .base=NULL if not set */
+    int send_delegated_uri;     /* whether to send the rewritten HTTP_HOST & REQUEST_URI by delegation, or the original */
+    struct {
+        void (*dispose)(h2o_fastcgi_handler_t *handler, void *data);
+        void *data;
+    } callbacks;
+} h2o_fastcgi_config_vars_t;
+
+/**
+ * registers the fastcgi handler to the context
+ */
+h2o_fastcgi_handler_t *h2o_fastcgi_register_by_hostport(h2o_pathconf_t *pathconf, const char *host, uint16_t port,
+                                                        h2o_fastcgi_config_vars_t *vars);
+/**
+ * registers the fastcgi handler to the context
+ */
+h2o_fastcgi_handler_t *h2o_fastcgi_register_by_address(h2o_pathconf_t *pathconf, struct sockaddr *sa, socklen_t salen,
+                                                       h2o_fastcgi_config_vars_t *vars);
+/**
+ * registers the fastcgi handler to the context
+ */
+h2o_fastcgi_handler_t *h2o_fastcgi_register_by_spawnproc(h2o_pathconf_t *pathconf, char **argv, h2o_fastcgi_config_vars_t *vars);
+/**
+ * registers the configurator
+ */
+void h2o_fastcgi_register_configurator(h2o_globalconf_t *conf);
+
+/* lib/file.c */
+
+enum {
+    H2O_FILE_FLAG_NO_ETAG = 0x1,
+    H2O_FILE_FLAG_DIR_LISTING = 0x2,
+    H2O_FILE_FLAG_SEND_COMPRESSED = 0x4,
+    H2O_FILE_FLAG_GUNZIP = 0x8
+};
+
+typedef struct st_h2o_file_handler_t h2o_file_handler_t;
+
+extern const char **h2o_file_default_index_files;
+
+/**
+ * sends given file as the response to the client
+ */
+int h2o_file_send(h2o_req_t *req, int status, const char *reason, const char *path, h2o_iovec_t mime_type, int flags);
+/**
+ * registers a handler that serves a directory of statically-served files
+ * @param pathconf
+ * @param virtual_path
+ * @param real_path
+ * @param index_files optional NULL-terminated list of of filenames to be considered as the "directory-index"
+ * @param mimemap the mimemap (h2o_mimemap_create is called internally if the argument is NULL)
+ */
+h2o_file_handler_t *h2o_file_register(h2o_pathconf_t *pathconf, const char *real_path, const char **index_files,
+                                      h2o_mimemap_t *mimemap, int flags);
+/**
+ * registers a handler that serves a specific file
+ * @param pathconf
+ * @param virtual_path
+ * @param real_path
+ * @param index_files optional NULL-terminated list of of filenames to be considered as the "directory-index"
+ * @param mimemap the mimemap (h2o_mimemap_create is called internally if the argument is NULL)
+ */
+h2o_handler_t *h2o_file_register_file(h2o_pathconf_t *pathconf, const char *real_path, h2o_mimemap_type_t *mime_type, int flags);
+/**
+ * returns the associated mimemap
+ */
+h2o_mimemap_t *h2o_file_get_mimemap(h2o_file_handler_t *handler);
+/**
+ * registers the configurator
+ */
+void h2o_file_register_configurator(h2o_globalconf_t *conf);
+
+/* lib/headers.c */
+
+enum {
+    H2O_HEADERS_CMD_NULL,
+    H2O_HEADERS_CMD_ADD,        /* adds a new header line */
+    H2O_HEADERS_CMD_APPEND,     /* adds a new header line or contenates to the existing header */
+    H2O_HEADERS_CMD_MERGE,      /* merges the value into a comma-listed values of the named header */
+    H2O_HEADERS_CMD_SET,        /* sets a header line, overwriting the existing one (if any) */
+    H2O_HEADERS_CMD_SETIFEMPTY, /* sets a header line if empty */
+    H2O_HEADERS_CMD_UNSET       /* removes the named header(s) */
+};
+
+struct st_h2o_headers_command_t {
+    int cmd;
+    h2o_iovec_t *name; /* maybe a token */
+    h2o_iovec_t value;
+};
+
+/**
+ * registers a list of commands terminated by cmd==H2O_HEADERS_CMD_NULL
+ */
+void h2o_headers_register(h2o_pathconf_t *pathconf, h2o_headers_command_t *cmds);
+/**
+ * returns whether if the given name can be registered to the filter
+ */
+int h2o_headers_is_prohibited_name(const h2o_token_t *token);
+/**
+ * registers the configurator
+ */
+void h2o_headers_register_configurator(h2o_globalconf_t *conf);
+
+/* lib/proxy.c */
+
+typedef struct st_h2o_proxy_config_vars_t {
+    uint64_t io_timeout;
+    unsigned preserve_host : 1;
+    unsigned use_proxy_protocol : 1;
+    uint64_t keepalive_timeout; /* in milliseconds; set to zero to disable keepalive */
+    struct {
+        int enabled;
+        uint64_t timeout;
+    } websocket;
+    h2o_headers_command_t *headers_cmds;
+    SSL_CTX *ssl_ctx; /* optional */
+} h2o_proxy_config_vars_t;
+
+/**
+ * registers the reverse proxy handler to the context
+ */
+void h2o_proxy_register_reverse_proxy(h2o_pathconf_t *pathconf, h2o_url_t *upstream, h2o_proxy_config_vars_t *config);
+/**
+ * registers the configurator
+ */
+void h2o_proxy_register_configurator(h2o_globalconf_t *conf);
+
+/* lib/redirect.c */
+
+typedef struct st_h2o_redirect_handler_t h2o_redirect_handler_t;
+
+/**
+ * registers the redirect handler to the context
+ * @param pathconf
+ * @param internal whether if the redirect is internal or external
+ * @param status status code to be sent (e.g. 301, 303, 308, ...)
+ * @param prefix prefix of the destitation URL
+ */
+h2o_redirect_handler_t *h2o_redirect_register(h2o_pathconf_t *pathconf, int internal, int status, const char *prefix);
+/**
+ * registers the configurator
+ */
+void h2o_redirect_register_configurator(h2o_globalconf_t *conf);
+
+/* lib/handler/reproxy.c */
+
+typedef struct st_h2o_reproxy_handler_t h2o_reproxy_handler_t;
+
+/**
+ * registers the reproxy filter
+ */
+void h2o_reproxy_register(h2o_pathconf_t *pathconf);
+/**
+ * registers the configurator
+ */
+void h2o_reproxy_register_configurator(h2o_globalconf_t *conf);
+
+/* lib/handler/status.c */
+
+/**
+ * registers the status handler
+ */
+void h2o_status_register(h2o_pathconf_t *pathconf);
+/**
+ * registers the duration handler
+ */
+void h2o_duration_stats_register(h2o_globalconf_t *conf);
+/**
+ * registers the configurator
+ */
+void h2o_status_register_configurator(h2o_globalconf_t *conf);
+
+/* lib/handler/headers_util.c */
+
+/**
+ * appends a headers command to the list
+ */
+void h2o_headers_append_command(h2o_headers_command_t **cmds, int cmd, h2o_iovec_t *name, h2o_iovec_t value);
+/**
+ * rewrite headers by the command provided
+ */
+void h2o_rewrite_headers(h2o_mem_pool_t *pool, h2o_headers_t *headers, h2o_headers_command_t *cmd);
+
+/* lib/handler/http2_debug_state.c */
+
+/**
+ * registers the http2 debug state handler
+ */
+void h2o_http2_debug_state_register(h2o_hostconf_t *hostconf, int hpack_enabled);
+/**
+ * registers the configurator
+ */
+void h2o_http2_debug_state_register_configurator(h2o_globalconf_t *conf);
+
+/* inline defs */
+
+#ifdef H2O_NO_64BIT_ATOMICS
+extern pthread_mutex_t h2o_conn_id_mutex;
+#endif
+
+inline h2o_conn_t *h2o_create_connection(size_t sz, h2o_context_t *ctx, h2o_hostconf_t **hosts, struct timeval connected_at,
+                                         const h2o_conn_callbacks_t *callbacks)
+{
+    h2o_conn_t *conn = (h2o_conn_t *)h2o_mem_alloc(sz);
+
+    conn->ctx = ctx;
+    conn->hosts = hosts;
+    conn->connected_at = connected_at;
+#ifdef H2O_NO_64BIT_ATOMICS
+    pthread_mutex_lock(&h2o_conn_id_mutex);
+    conn->id = ++h2o_connection_id;
+    pthread_mutex_unlock(&h2o_conn_id_mutex);
+#else
+    conn->id = __sync_add_and_fetch(&h2o_connection_id, 1);
+#endif
+    conn->callbacks = callbacks;
+
+    return conn;
+}
+
+inline void h2o_proceed_response(h2o_req_t *req)
+{
+    if (req->_generator != NULL) {
+        req->_generator->proceed(req->_generator, req);
+    } else {
+        req->_ostr_top->do_send(req->_ostr_top, req, NULL, 0, H2O_SEND_STATE_FINAL);
+    }
+}
+
+inline h2o_iovec_t *h2o_req_getenv(h2o_req_t *req, const char *name, size_t name_len, int allocate_if_not_found)
+{
+    size_t i;
+    for (i = 0; i != req->env.size; i += 2)
+        if (h2o_memis(req->env.entries[i].base, req->env.entries[i].len, name, name_len))
+            return req->env.entries + i + 1;
+    if (!allocate_if_not_found)
+        return NULL;
+    h2o_vector_reserve(&req->pool, &req->env, req->env.size + 2);
+    req->env.entries[req->env.size++] = h2o_iovec_init(name, name_len);
+    req->env.entries[req->env.size++] = h2o_iovec_init(NULL, 0);
+    return req->env.entries + req->env.size - 1;
+}
+
+inline void h2o_req_unsetenv(h2o_req_t *req, const char *name, size_t name_len)
+{
+    size_t i;
+    for (i = 0; i != req->env.size; i += 2)
+        if (h2o_memis(req->env.entries[i].base, req->env.entries[i].len, name, name_len))
+            goto Found;
+    /* not found */
+    return;
+Found:
+    memmove(req->env.entries + i, req->env.entries + i + 2, req->env.size - i - 2);
+    req->env.size -= 2;
+}
+
+inline h2o_send_state_t h2o_pull(h2o_req_t *req, h2o_ostream_pull_cb cb, h2o_iovec_t *buf)
+{
+    h2o_send_state_t send_state;
+    assert(req->_generator != NULL);
+    send_state = cb(req->_generator, req, buf);
+    if (!h2o_send_state_is_in_progress(send_state))
+        req->_generator = NULL;
+    return send_state;
+}
+
+inline void h2o_setup_next_ostream(h2o_req_t *req, h2o_ostream_t **slot)
+{
+    h2o_filter_t *next;
+
+    if (req->_next_filter_index < req->pathconf->filters.size) {
+        next = req->pathconf->filters.entries[req->_next_filter_index++];
+        next->on_setup_ostream(next, req, slot);
+    }
+}
+
+inline void h2o_setup_next_prefilter(h2o_req_prefilter_t *self, h2o_req_t *req, h2o_ostream_t **slot)
+{
+    h2o_req_prefilter_t *next = self->next;
+
+    if (next != NULL)
+        next->on_setup_ostream(next, req, slot);
+    else
+        h2o_setup_next_ostream(req, slot);
+}
+
+inline struct timeval *h2o_get_timestamp(h2o_context_t *ctx, h2o_mem_pool_t *pool, h2o_timestamp_t *ts)
+{
+    uint64_t now = h2o_now(ctx->loop);
+
+    if (ctx->_timestamp_cache.uv_now_at != now) {
+        h2o_context_update_timestamp_cache(ctx);
+    }
+
+    if (ts != NULL) {
+        ts->at = ctx->_timestamp_cache.tv_at;
+        h2o_mem_link_shared(pool, ctx->_timestamp_cache.value);
+        ts->str = ctx->_timestamp_cache.value;
+    }
+
+    return &ctx->_timestamp_cache.tv_at;
+}
+
+inline void *h2o_context_get_handler_context(h2o_context_t *ctx, h2o_handler_t *handler)
+{
+    return ctx->_module_configs[handler->_config_slot];
+}
+
+inline void h2o_context_set_handler_context(h2o_context_t *ctx, h2o_handler_t *handler, void *handler_ctx)
+{
+    ctx->_module_configs[handler->_config_slot] = handler_ctx;
+}
+
+inline void *h2o_context_get_filter_context(h2o_context_t *ctx, h2o_filter_t *filter)
+{
+    return ctx->_module_configs[filter->_config_slot];
+}
+
+inline void h2o_context_set_filter_context(h2o_context_t *ctx, h2o_filter_t *filter, void *filter_ctx)
+{
+    ctx->_module_configs[filter->_config_slot] = filter_ctx;
+}
+
+inline void *h2o_context_get_logger_context(h2o_context_t *ctx, h2o_logger_t *logger)
+{
+    return ctx->_module_configs[logger->_config_slot];
+}
+
+inline void **h2o_context_get_storage(h2o_context_t *ctx, size_t *key, void (*dispose_cb)(void *))
+{
+    /* SIZE_MAX might not be available in case the file is included from a C++ source file */
+    size_t size_max = (size_t)-1;
+    if (*key == size_max)
+        *key = ctx->storage.size;
+    if (ctx->storage.size <= *key) {
+        h2o_vector_reserve(NULL, &ctx->storage, *key + 1);
+        memset(ctx->storage.entries + ctx->storage.size, 0, (*key + 1 - ctx->storage.size) * sizeof(ctx->storage.entries[0]));
+        ctx->storage.size = *key + 1;
+    }
+
+    ctx->storage.entries[*key].dispose = dispose_cb;
+    return &ctx->storage.entries[*key].data;
+}
+
+static inline void h2o_context_set_logger_context(h2o_context_t *ctx, h2o_logger_t *logger, void *logger_ctx)
+{
+    ctx->_module_configs[logger->_config_slot] = logger_ctx;
+}
+
+static inline void h2o_doublebuffer_init(h2o_doublebuffer_t *db, h2o_buffer_prototype_t *prototype)
+{
+    h2o_buffer_init(&db->buf, prototype);
+    db->bytes_inflight = 0;
+}
+
+static inline void h2o_doublebuffer_dispose(h2o_doublebuffer_t *db)
+{
+    h2o_buffer_dispose(&db->buf);
+}
+
+static inline h2o_iovec_t h2o_doublebuffer_prepare(h2o_doublebuffer_t *db, h2o_buffer_t **receiving, size_t max_bytes)
+{
+    assert(db->bytes_inflight == 0);
+
+    if (db->buf->size == 0) {
+        if ((*receiving)->size == 0)
+            return h2o_iovec_init(NULL, 0);
+        /* swap buffers */
+        h2o_buffer_t *t = db->buf;
+        db->buf = *receiving;
+        *receiving = t;
+    }
+    if ((db->bytes_inflight = db->buf->size) > max_bytes)
+        db->bytes_inflight = max_bytes;
+    return h2o_iovec_init(db->buf->bytes, db->bytes_inflight);
+}
+
+static inline void h2o_doublebuffer_consume(h2o_doublebuffer_t *db)
+{
+    assert(db->bytes_inflight != 0);
+    h2o_buffer_consume(&db->buf, db->bytes_inflight);
+    db->bytes_inflight = 0;
+}
+
+#define COMPUTE_DURATION(name, from, until)                                                                                        \
+    static inline int h2o_time_compute_##name(struct st_h2o_req_t *req, int64_t *delta_usec)                                       \
+    {                                                                                                                              \
+        if (h2o_timeval_is_null((from)) || h2o_timeval_is_null((until))) {                                                         \
+            return 0;                                                                                                              \
+        }                                                                                                                          \
+        *delta_usec = h2o_timeval_subtract((from), (until));                                                                       \
+        return 1;                                                                                                                  \
+    }
+
+COMPUTE_DURATION(connect_time, &req->conn->connected_at, &req->timestamps.request_begin_at);
+COMPUTE_DURATION(header_time, &req->timestamps.request_begin_at, h2o_timeval_is_null(&req->timestamps.request_body_begin_at)
+                                                                     ? &req->processed_at.at
+                                                                     : &req->timestamps.request_body_begin_at);
+COMPUTE_DURATION(body_time, h2o_timeval_is_null(&req->timestamps.request_body_begin_at) ? &req->processed_at.at
+                                                                                        : &req->timestamps.request_body_begin_at,
+                 &req->processed_at.at);
+COMPUTE_DURATION(request_total_time, &req->timestamps.request_begin_at, &req->processed_at.at);
+COMPUTE_DURATION(process_time, &req->processed_at.at, &req->timestamps.response_start_at);
+COMPUTE_DURATION(response_time, &req->timestamps.response_start_at, &req->timestamps.response_end_at);
+COMPUTE_DURATION(duration, &req->timestamps.request_begin_at, &req->timestamps.response_end_at);
+
+#undef COMPUTE_DURATION
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif