Mercurial > hg > nginx
view src/http/ngx_http_postpone_filter_module.c @ 7142:b9d919b53593 stable-1.12
Stream: relaxed next upstream condition (ticket #1317).
When switching to a next upstream, some buffers could be stuck in the middle
of the filter chain. A condition existed that raised an error when this
happened. As it turned out, this condition prevented switching to a next
upstream if ssl preread was used with the TCP protocol (see the ticket).
In fact, the condition does not make sense for TCP, since after successful
connection to an upstream switching to another upstream never happens. As for
UDP, the issue with stuck buffers is unlikely to happen, but is still possible.
Specifically, if a filter delays sending data to upstream.
The condition can be relaxed to only check the "buffered" bitmask of the
upstream connection. The new condition is simpler and fixes the ticket issue
as well. Additionally, the upstream_out chain is now reset for UDP prior to
connecting to a new upstream to prevent repeating the client data twice.
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Mon, 11 Sep 2017 15:32:31 +0300 |
parents | f026adb935ad |
children | d87f29d764ce |
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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_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 != c->data) { if (in) { ngx_http_postpone_filter_add(r, in); 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) { ngx_http_postpone_filter_add(r, in); } 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_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; }