Mercurial > hg > nginx
view src/http/ngx_http_postpone_filter_module.c @ 9086:f68fdb017141 quic
QUIC: optimized sending stream response.
When a stream is created by client, it's often the case that nginx will send
immediate response on that stream. An example is HTTP/3 request stream, which
in most cases quickly replies with at least HTTP headers.
QUIC stream init handlers are called from a posted event. Output QUIC
frames are also sent to client from a posted event, called the push event.
If the push event is posted before the stream init event, then output produced
by stream may trigger sending an extra UDP datagram. To address this, push
event is now re-posted when a new stream init event is posted.
An example is handling 0-RTT packets. Client typically sends an init packet
coalesced with a 0-RTT packet. Previously, nginx replied with a padded CRYPTO
datagram, followed by a 1-RTT stream reply datagram. Now CRYPTO and STREAM
packets are coalesced in one reply datagram, which saves bandwidth.
Other examples include coalescing 1-RTT first stream response, and
MAX_STREAMS/STREAM sent in response to ACK/STREAM.
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Mon, 03 Apr 2023 16:17:12 +0400 |
parents | 43585e0e12a3 |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> static ngx_int_t ngx_http_postpone_filter_add(ngx_http_request_t *r, ngx_chain_t *in); static ngx_int_t ngx_http_postpone_filter_in_memory(ngx_http_request_t *r, ngx_chain_t *in); static ngx_int_t ngx_http_postpone_filter_init(ngx_conf_t *cf); static ngx_http_module_t ngx_http_postpone_filter_module_ctx = { NULL, /* preconfiguration */ ngx_http_postpone_filter_init, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ NULL, /* create location configuration */ NULL /* merge location configuration */ }; ngx_module_t ngx_http_postpone_filter_module = { NGX_MODULE_V1, &ngx_http_postpone_filter_module_ctx, /* module context */ NULL, /* module directives */ NGX_HTTP_MODULE, /* module type */ NULL, /* init master */ NULL, /* init module */ NULL, /* init process */ NULL, /* init thread */ NULL, /* exit thread */ NULL, /* exit process */ NULL, /* exit master */ NGX_MODULE_V1_PADDING }; static ngx_http_output_body_filter_pt ngx_http_next_body_filter; static ngx_int_t ngx_http_postpone_filter(ngx_http_request_t *r, ngx_chain_t *in) { ngx_connection_t *c; ngx_http_postponed_request_t *pr; c = r->connection; ngx_log_debug3(NGX_LOG_DEBUG_HTTP, c->log, 0, "http postpone filter \"%V?%V\" %p", &r->uri, &r->args, in); if (r->subrequest_in_memory) { return ngx_http_postpone_filter_in_memory(r, in); } if (r != c->data) { if (in) { if (ngx_http_postpone_filter_add(r, in) != NGX_OK) { return NGX_ERROR; } return NGX_OK; } #if 0 /* TODO: SSI may pass NULL */ ngx_log_error(NGX_LOG_ALERT, c->log, 0, "http postpone filter NULL inactive request"); #endif return NGX_OK; } if (r->postponed == NULL) { if (in || c->buffered) { return ngx_http_next_body_filter(r->main, in); } return NGX_OK; } if (in) { if (ngx_http_postpone_filter_add(r, in) != NGX_OK) { return NGX_ERROR; } } do { pr = r->postponed; if (pr->request) { ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0, "http postpone filter wake \"%V?%V\"", &pr->request->uri, &pr->request->args); r->postponed = pr->next; c->data = pr->request; return ngx_http_post_request(pr->request, NULL); } if (pr->out == NULL) { ngx_log_error(NGX_LOG_ALERT, c->log, 0, "http postpone filter NULL output"); } else { ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0, "http postpone filter output \"%V?%V\"", &r->uri, &r->args); if (ngx_http_next_body_filter(r->main, pr->out) == NGX_ERROR) { return NGX_ERROR; } } r->postponed = pr->next; } while (r->postponed); return NGX_OK; } static ngx_int_t ngx_http_postpone_filter_add(ngx_http_request_t *r, ngx_chain_t *in) { ngx_http_postponed_request_t *pr, **ppr; if (r->postponed) { for (pr = r->postponed; pr->next; pr = pr->next) { /* void */ } if (pr->request == NULL) { goto found; } ppr = &pr->next; } else { ppr = &r->postponed; } pr = ngx_palloc(r->pool, sizeof(ngx_http_postponed_request_t)); if (pr == NULL) { return NGX_ERROR; } *ppr = pr; pr->request = NULL; pr->out = NULL; pr->next = NULL; found: if (ngx_chain_add_copy(r->pool, &pr->out, in) == NGX_OK) { return NGX_OK; } return NGX_ERROR; } static ngx_int_t ngx_http_postpone_filter_in_memory(ngx_http_request_t *r, ngx_chain_t *in) { size_t len; ngx_buf_t *b; ngx_connection_t *c; ngx_http_core_loc_conf_t *clcf; c = r->connection; ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0, "http postpone filter in memory"); if (r->out == NULL) { clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module); if (r->headers_out.content_length_n != -1) { len = r->headers_out.content_length_n; if (len > clcf->subrequest_output_buffer_size) { ngx_log_error(NGX_LOG_ERR, c->log, 0, "too big subrequest response: %uz", len); return NGX_ERROR; } } else { len = clcf->subrequest_output_buffer_size; } b = ngx_create_temp_buf(r->pool, len); if (b == NULL) { return NGX_ERROR; } b->last_buf = 1; r->out = ngx_alloc_chain_link(r->pool); if (r->out == NULL) { return NGX_ERROR; } r->out->buf = b; r->out->next = NULL; } b = r->out->buf; for ( /* void */ ; in; in = in->next) { if (ngx_buf_special(in->buf)) { continue; } len = in->buf->last - in->buf->pos; if (len > (size_t) (b->end - b->last)) { ngx_log_error(NGX_LOG_ERR, c->log, 0, "too big subrequest response"); return NGX_ERROR; } ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0, "http postpone filter in memory %uz bytes", len); b->last = ngx_cpymem(b->last, in->buf->pos, len); in->buf->pos = in->buf->last; } return NGX_OK; } static ngx_int_t ngx_http_postpone_filter_init(ngx_conf_t *cf) { ngx_http_next_body_filter = ngx_http_top_body_filter; ngx_http_top_body_filter = ngx_http_postpone_filter; return NGX_OK; }