Mercurial > hg > nginx-quic
view src/core/ngx_buf.h @ 6750:cb330cd39030 stable-1.10
HTTP/2: implemented preread buffer for request body (closes #959).
Previously, the stream's window was kept zero in order to prevent a client
from sending the request body before it was requested (see 887cca40ba6a for
details). Until such initial window was acknowledged all requests with
data were rejected (see 0aa07850922f for details).
That approach revealed a number of problems:
1. Some clients (notably MS IE/Edge, Safari, iOS applications) show an error
or even crash if a stream is rejected;
2. This requires at least one RTT for every request with body before the
client receives window update and able to send data.
To overcome these problems the new directive "http2_body_preread_size" is
introduced. It sets the initial window and configures a special per stream
preread buffer that is used to save all incoming data before the body is
requested and processed.
If the directive's value is lower than the default initial window (65535),
as previously, all streams with data will be rejected until the new window
is acknowledged. Otherwise, no special processing is used and all requests
with data are welcome right from the connection start.
The default value is chosen to be 64k, which is bigger than the default
initial window. Setting it to zero is fully complaint to the previous
behavior.
author | Valentin Bartenev <vbart@nginx.com> |
---|---|
date | Tue, 24 May 2016 17:37:52 +0300 |
parents | 1fdba317ee6d |
children | e8d4c9e9682a |
line wrap: on
line source
/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #ifndef _NGX_BUF_H_INCLUDED_ #define _NGX_BUF_H_INCLUDED_ #include <ngx_config.h> #include <ngx_core.h> typedef void * ngx_buf_tag_t; typedef struct ngx_buf_s ngx_buf_t; struct ngx_buf_s { u_char *pos; u_char *last; off_t file_pos; off_t file_last; u_char *start; /* start of buffer */ u_char *end; /* end of buffer */ ngx_buf_tag_t tag; ngx_file_t *file; ngx_buf_t *shadow; /* the buf's content could be changed */ unsigned temporary:1; /* * the buf's content is in a memory cache or in a read only memory * and must not be changed */ unsigned memory:1; /* the buf's content is mmap()ed and must not be changed */ unsigned mmap:1; unsigned recycled:1; unsigned in_file:1; unsigned flush:1; unsigned sync:1; unsigned last_buf:1; unsigned last_in_chain:1; unsigned last_shadow:1; unsigned temp_file:1; /* STUB */ int num; }; struct ngx_chain_s { ngx_buf_t *buf; ngx_chain_t *next; }; typedef struct { ngx_int_t num; size_t size; } ngx_bufs_t; typedef struct ngx_output_chain_ctx_s ngx_output_chain_ctx_t; typedef ngx_int_t (*ngx_output_chain_filter_pt)(void *ctx, ngx_chain_t *in); #if (NGX_HAVE_FILE_AIO) typedef void (*ngx_output_chain_aio_pt)(ngx_output_chain_ctx_t *ctx, ngx_file_t *file); #endif struct ngx_output_chain_ctx_s { ngx_buf_t *buf; ngx_chain_t *in; ngx_chain_t *free; ngx_chain_t *busy; unsigned sendfile:1; unsigned directio:1; #if (NGX_HAVE_ALIGNED_DIRECTIO) unsigned unaligned:1; #endif unsigned need_in_memory:1; unsigned need_in_temp:1; #if (NGX_HAVE_FILE_AIO || NGX_THREADS) unsigned aio:1; #endif #if (NGX_HAVE_FILE_AIO) ngx_output_chain_aio_pt aio_handler; #if (NGX_HAVE_AIO_SENDFILE) ssize_t (*aio_preload)(ngx_buf_t *file); #endif #endif #if (NGX_THREADS) ngx_int_t (*thread_handler)(ngx_thread_task_t *task, ngx_file_t *file); ngx_thread_task_t *thread_task; #endif off_t alignment; ngx_pool_t *pool; ngx_int_t allocated; ngx_bufs_t bufs; ngx_buf_tag_t tag; ngx_output_chain_filter_pt output_filter; void *filter_ctx; }; typedef struct { ngx_chain_t *out; ngx_chain_t **last; ngx_connection_t *connection; ngx_pool_t *pool; off_t limit; } ngx_chain_writer_ctx_t; #define NGX_CHAIN_ERROR (ngx_chain_t *) NGX_ERROR #define ngx_buf_in_memory(b) (b->temporary || b->memory || b->mmap) #define ngx_buf_in_memory_only(b) (ngx_buf_in_memory(b) && !b->in_file) #define ngx_buf_special(b) \ ((b->flush || b->last_buf || b->sync) \ && !ngx_buf_in_memory(b) && !b->in_file) #define ngx_buf_sync_only(b) \ (b->sync \ && !ngx_buf_in_memory(b) && !b->in_file && !b->flush && !b->last_buf) #define ngx_buf_size(b) \ (ngx_buf_in_memory(b) ? (off_t) (b->last - b->pos): \ (b->file_last - b->file_pos)) ngx_buf_t *ngx_create_temp_buf(ngx_pool_t *pool, size_t size); ngx_chain_t *ngx_create_chain_of_bufs(ngx_pool_t *pool, ngx_bufs_t *bufs); #define ngx_alloc_buf(pool) ngx_palloc(pool, sizeof(ngx_buf_t)) #define ngx_calloc_buf(pool) ngx_pcalloc(pool, sizeof(ngx_buf_t)) ngx_chain_t *ngx_alloc_chain_link(ngx_pool_t *pool); #define ngx_free_chain(pool, cl) \ cl->next = pool->chain; \ pool->chain = cl ngx_int_t ngx_output_chain(ngx_output_chain_ctx_t *ctx, ngx_chain_t *in); ngx_int_t ngx_chain_writer(void *ctx, ngx_chain_t *in); ngx_int_t ngx_chain_add_copy(ngx_pool_t *pool, ngx_chain_t **chain, ngx_chain_t *in); ngx_chain_t *ngx_chain_get_free_buf(ngx_pool_t *p, ngx_chain_t **free); void ngx_chain_update_chains(ngx_pool_t *p, ngx_chain_t **free, ngx_chain_t **busy, ngx_chain_t **out, ngx_buf_tag_t tag); off_t ngx_chain_coalesce_file(ngx_chain_t **in, off_t limit); ngx_chain_t *ngx_chain_update_sent(ngx_chain_t *in, off_t sent); #endif /* _NGX_BUF_H_INCLUDED_ */