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.

/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_STREAM_SSL_H_INCLUDED_
#define _NGX_STREAM_SSL_H_INCLUDED_


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_stream.h>


typedef struct {
    ngx_msec_t       handshake_timeout;

    ngx_flag_t       prefer_server_ciphers;

    ngx_ssl_t        ssl;

    ngx_uint_t       protocols;

    ssize_t          builtin_session_cache;

    time_t           session_timeout;

    ngx_str_t        certificate;
    ngx_str_t        certificate_key;
    ngx_str_t        dhparam;
    ngx_str_t        ecdh_curve;

    ngx_str_t        ciphers;

    ngx_array_t     *passwords;

    ngx_shm_zone_t  *shm_zone;

    ngx_flag_t       session_tickets;
    ngx_array_t     *session_ticket_keys;
} ngx_stream_ssl_conf_t;


extern ngx_module_t  ngx_stream_ssl_module;


#endif /* _NGX_STREAM_SSL_H_INCLUDED_ */