Mercurial > hg > nginx
view src/http/ngx_http_postpone_filter_module.c @ 9143:48691bab4474
QUIC: fixed probe-congestion deadlock.
When probe timeout expired while congestion window was exhausted, probe PINGs
could not be sent. As a result, lost packets could not be declared lost and
congestion window could not be freed for new packets. This deadlock
continued until connection idle timeout expiration.
Now PINGs are sent separately from the frame queue without congestion control,
as specified by RFC 9002, Section 7:
An endpoint MUST NOT send a packet if it would cause bytes_in_flight
(see Appendix B.2) to be larger than the congestion window, unless the
packet is sent on a PTO timer expiration (see Section 6.2) or when entering
recovery (see Section 7.3.2).
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Mon, 14 Aug 2023 08:28:30 +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; }