view src/http/ngx_http_postpone_filter_module.c @ 6749:f88a145b093e stable-1.10

HTTP/2: the "421 Misdirected Request" response (closes #848). Since 4fbef397c753 nginx rejects with the 400 error any attempts of requesting different host over the same connection, if the relevant virtual server requires verification of a client certificate. While requesting hosts other than negotiated isn't something legal in HTTP/1.x, the HTTP/2 specification explicitly permits such requests for connection reuse and has introduced a special response code 421. According to RFC 7540 Section 9.1.2 this code can be sent by a server that is not configured to produce responses for the combination of scheme and authority that are included in the request URI. And the client may retry the request over a different connection. Now this code is used for requests that aren't authorized in current connection. After receiving the 421 response a client will be able to open a new connection, provide the required certificate and retry the request. Unfortunately, not all clients currently are able to handle it well. Notably Chrome just shows an error, while at least the latest version of Firefox retries the request over a new connection.
author Valentin Bartenev <vbart@nginx.com>
date Fri, 20 May 2016 18:41:17 +0300
parents f026adb935ad
children d87f29d764ce
line wrap: on
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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;
}