Name
    nginx_tcp_proxy_module - support TCP proxy with Nginx

Installation
    Download the latest stable version of the release tarball of this module
    from github (<http://github.com/yaoweibin/nginx_tcp_proxy_module>)

    Grab the nginx source code from nginx.org (<http://nginx.org/>), for
    example, the version 1.2.1 (see nginx compatibility), and then build the
    source with this module:

        $ wget 'http://nginx.org/download/nginx-1.2.1.tar.gz'
        $ tar -xzvf nginx-1.2.1.tar.gz
        $ cd nginx-1.2.1/
        $ patch -p1 < /path/to/nginx_tcp_proxy_module/tcp.patch

        $ ./configure --add-module=/path/to/nginx_tcp_proxy_module

        $ make
        $ make install

Synopsis
    http {

        server {
            listen 80;

            location /status {
                tcp_check_status;
            }
        }
    }

    #You can also include tcp_proxy.conf file individually

    #include /path/to/tcp_proxy.conf;

    tcp {

        upstream cluster {
            # simple round-robin
            server 192.168.0.1:80;
            server 192.168.0.2:80;

            check interval=3000 rise=2 fall=5 timeout=1000;

            #check interval=3000 rise=2 fall=5 timeout=1000 type=ssl_hello;

            #check interval=3000 rise=2 fall=5 timeout=1000 type=http;
            #check_http_send "GET / HTTP/1.0\r\n\r\n";
            #check_http_expect_alive http_2xx http_3xx;
        }

        server {
            listen 8888;

            proxy_pass cluster;
        }
    }

Description
    This module actually include many modules: ngx_tcp_module,
    ngx_tcp_core_module, ngx_tcp_upstream_module, ngx_tcp_proxy_module,
    ngx_tcp_websocket_module, ngx_tcp_ssl_module,
    ngx_tcp_upstream_ip_hash_module. All these modules work together to
    support TCP proxy with Nginx. I also added other features: ip_hash,
    upstream server health check, status monitor.

    The motivation of writing these modules is Nginx's high performance and
    robustness. At first, I developed this module just for general TCP
    proxy. And now, this module is frequently used in websocket reverse
    proxying.

    Note, You can't use the same listening port with HTTP modules.

Directives
  ngx_tcp_moodule
   tcp
    syntax: *tcp {...}*

    default: *none*

    context: *main*

    description: All the tcp related directives are contained in the tcp
    block.

    ngx_tcp_core_moodule

   server
    syntax: *server {...}*

    default: *none*

    context: *tcp*

    description: All the specific server directives are contained in the
    server block.

   listen
    syntax: *listen address:port [ bind | ssl | default]*

    default: *none*

    context: *server*

    description: The same as listen
    (<http://wiki.nginx.org/NginxMailCoreModule#listen>). The parameter of
    default means the default server if you have several server blocks with
    the same port.

   access_log
    syntax: *access_log path [buffer=size] | off*

    default: *access_log logs/tcp_access.log*

    context: *tcp, server*

    description: Set the access.log. Each record's format is like this:

    log_time worker_process_pid client_ip host_ip accept_time upstream_ip
    bytes_read bytes_write

    2011/08/02 06:19:07 [5972] 127.0.0.1 0.0.0.0:1982 2011/08/02 06:18:19
    172.19.0.129:80 80 236305

    *   *log_time*: The current time when writing this log. The log action
        is called when the proxy session is closed.

    *   *worker_process_pid*: the pid of worker process

    *   *client_ip*: the client ip

    *   *host_ip*: the server ip and port

    *   *accept_time*: the time when the server accepts client's connection

    *   *upstream_ip*: the upstream server's ip

    *   *bytes_read*: the bytes read from client

    *   *bytes_write*: the bytes written to client

   allow
    syntax: *allow [ address | CIDR | all ]*

    default: *none*

    context: *server*

    description: Directive grants access for the network or addresses
    indicated.

   deny
    syntax: *deny [ address | CIDR | all ]*

    default: *none*

    context: *server*

    description: Directive grants access for the network or addresses
    indicated.

   so_keepalive
    syntax: *so_keepalive on|off*

    default: *off*

    context: *main, server*

    description: The same as so_keepalive
    (<http://wiki.nginx.org/NginxMailCoreModule#so_keepalive>).

   tcp_nodelay
    syntax: *tcp_nodelay on|off*

    default: *on*

    context: *main, server*

    description: The same as tcp_nodelay
    (<http://wiki.nginx.org/NginxHttpCoreModule#tcp_nodelay>).

   timeout
    syntax: *timeout milliseconds*

    default: *60000*

    context: *main, server*

    description: set the timeout value with clients.

   server_name
    syntax: *server_name name*

    default: *The name of the host, obtained through gethostname()*

    context: *tcp, server*

    description: The same as server_name
    (<http://wiki.nginx.org/NginxMailCoreModule#server_name>). You can
    specify several server name in different server block with the same
    port. They can be used in websocket module.

   resolver
    syntax: *resolver address*

    default: *none*

    context: *tcp, server*

    description: DNS server

   resolver_timeout
    syntax: *resolver_timeout time*

    default: *30s*

    context: *tcp, server*

    description: Resolver timeout in seconds.

  ngx_tcp_upstream_module
   upstream
    syntax: *upstream {...}*

    default: *none*

    context: *tcp*

    description: All the upstream directives are contained in this block.
    The upstream server will be dispatched with round robin by default.

   server
    syntax: *server name [parameters]*

    default: *none*

    context: *upstream*

    description: Most of the parameters are the same as server
    (<http://wiki.nginx.org/NginxHttpUpstreamModule#server>). Default port
    is 80.

   check
    syntax: *check interval=milliseconds [fall=count] [rise=count]
    [timeout=milliseconds] [type=tcp|ssl_hello|smtp|mysql|pop3|imap]*

    default: *none, if parameters omitted, default parameters are
    interval=30000 fall=5 rise=2 timeout=1000*

    context: *upstream*

    description: Add the health check for the upstream servers. At present,
    the check method is a simple tcp connect.

    The parameters' meanings are:

    *   *interval*: the check request's interval time.

    *   *fall*(fall_count): After fall_count check failures, the server is
        marked down.

    *   *rise*(rise_count): After rise_count check success, the server is
        marked up.

    *   *timeout*: the check request's timeout.

    *   *type*: the check protocol type:

        1.  *tcp* is a simple tcp socket connect and peek one byte.

        2.  *ssl_hello* sends a client ssl hello packet and receives the
            server ssl hello packet.

        3.  *http* sends a http request packet, receives and parses the http
            response to diagnose if the upstream server is alive.

        4.  *smtp* sends a smtp request packet, receives and parses the smtp
            response to diagnose if the upstream server is alive. The
            response begins with '2' should be an OK response.

        5.  *mysql* connects to the mysql server, receives the greeting
            response to diagnose if the upstream server is alive.

        6.  *pop3* receives and parses the pop3 response to diagnose if the
            upstream server is alive. The response begins with '+' should be
            an OK response.

        7.  *imap* connects to the imap server, receives the greeting
            response to diagnose if the upstream server is alive.

   check_http_send
    syntax: *check_http_send http_packet*

    default: *"GET / HTTP/1.0\r\n\r\n"*

    context: *upstream*

    description: If you set the check type is http, then the check function
    will sends this http packet to check the upstream server.

   check_http_expect_alive
    syntax: *check_http_expect_alive [ http_2xx | http_3xx | http_4xx |
    http_5xx ]*

    default: *http_2xx | http_3xx*

    context: *upstream*

    description: These status codes indicate the upstream server's http
    response is OK, the backend is alive.

   check_smtp_send
    syntax: *check_smtp_send smtp_packet*

    default: *"HELO smtp.localdomain\r\n"*

    context: *upstream*

    description: If you set the check type is smtp, then the check function
    will sends this smtp packet to check the upstream server.

   check_smtp_expect_alive
    syntax: *check_smtp_expect_alive [smtp_2xx | smtp_3xx | smtp_4xx |
    smtp_5xx]*

    default: *smtp_2xx*

    context: *upstream*

    description: These status codes indicate the upstream server's smtp
    response is OK, the backend is alive.

   check_shm_size
    syntax: *check_shm_size size*

    default: *(number_of_checked_upstream_blocks + 1) * pagesize*

    context: *tcp*

    description: If you store hundreds of servers in one upstream block, the
    shared memory for health check may be not enough, you can enlarged it by
    this directive.

   tcp_check_status
    syntax: *tcp_check_status*

    default: *none*

    context: *location*

    description: Display the health checking servers' status by HTTP. This
    directive is set in the http block.

    The table field meanings are:

    *   *Index*: The server index in the check table

    *   *Name* : The upstream server name

    *   *Status*: The marked status of the server.

    *   *Busyness*: The number of connections which are connecting to the
        server.

    *   *Rise counts*: Count the successful checking

    *   *Fall counts*: Count the unsuccessful checking

    *   *Access counts*: Count the times accessing to this server

    *   *Check type*: The type of the check packet

    ngx_tcp_upstream_busyness_module

   busyness
    syntax: *busyness*

    default: *none*

    context: *upstream*

    description: the upstream server will be dispatched by backend servers'
    busyness.

    ngx_tcp_upstream_ip_hash_module

   ip_hash
    syntax: *ip_hash*

    default: *none*

    context: *upstream*

    description: the upstream server will be dispatched by ip_hash.

  ngx_tcp_proxy_module
   proxy_pass
    syntax: *proxy_pass host:port*

    default: *none*

    context: *server*

    description: proxy the request to the backend server. Default port is
    80.

   proxy_buffer
    syntax: *proxy_buffer size*

    default: *4k*

    context: *tcp, server*

    description: set the size of proxy buffer.

   proxy_connect_timeout
    syntax: *proxy_connect_timeout miliseconds*

    default: *60000*

    context: *tcp, server*

    description: set the timeout value of connection to backends.

   proxy_read_timeout
    syntax: *proxy_read_timeout miliseconds*

    default: *60000*

    context: *tcp, server*

    description: set the timeout value of reading from backends.

   proxy_send_timeout
    syntax: *proxy_send_timeout miliseconds*

    default: *60000*

    context: *tcp, server*

    description: set the timeout value of sending to backends.

  ngx_tcp_websocket_module
   websocket_pass
    syntax: *websocket_pass [path] host:port*

    default: *none*

    context: *server*

    description: proxy the websocket request to the backend server. Default
    port is 80. You can specify several different paths in the same server
    block.

   websocket_buffer
    syntax: *websocket_buffer size*

    default: *4k*

    context: *tcp, server*

    description: set the size of proxy buffer.

   websocket_connect_timeout
    syntax: *websocket_connect_timeout miliseconds*

    default: *60000*

    context: *tcp, server*

    description: set the timeout value of connection to backends.

   websocket_read_timeout
    syntax: *websocket_read_timeout miliseconds*

    default: *60000*

    context: *tcp, server*

    description: set the timeout value of reading from backends. Your
    timeout will be the minimum of this and the *timeout* parameter, so if
    you want a long timeout for your websockets, make sure to set both
    paramaters.

   websocket_send_timeout
    syntax: *websocket_send_timeout miliseconds*

    default: *60000*

    context: *tcp, server*

    description: set the timeout value of sending to backends.

  ngx_tcp_ssl_module
    The default config file includes this ngx_tcp_ssl_module. If you want to
    just compile nginx without ngx_tcp_ssl_module, copy the
    ngx_tcp_proxy_module/config_without_ssl to ngx_tcp_proxy_module/config,
    reconfigrure and compile nginx.

   ssl
    syntax: *ssl [on|off] *

    default: *ssl off*

    context: *tcp, server*

    Enables SSL for a server.

   ssl_certificate
    syntax: *ssl_certificate file*

    default: *ssl_certificate cert.pem*

    context: *tcp, server*

    This directive specifies the file containing the certificate, in PEM
    format. This file can contain also other certificates and the server
    private key.

   ssl_certificate_key
    syntax: *ssl_certificate_key file*

    default: *ssl_certificate_key cert.pem*

    context: *tcp, server*

    This directive specifies the file containing the private key, in PEM
    format.

   ssl_client_certificate
    syntax: *ssl_client_certificate file*

    default: *none*

    context: *tcp, server*

    This directive specifies the file containing the CA (root) certificate,
    in PEM format, that is used for validating client certificates.

   ssl_dhparam
    syntax: *ssl_dhparam file*

    default: *none*

    context: *tcp, server*

    This directive specifies a file containing Diffie-Hellman key agreement
    protocol cryptographic parameters, in PEM format, utilized for
    exchanging session keys between server and client.

   ssl_ciphers
    syntax: *ssl_ciphers openssl_cipherlist_spec*

    default: *ssl_ciphers HIGH:!aNULL:!MD5*

    context: *tcp, server*

    This directive describes the list of cipher suites the server supports
    for establishing a secure connection. Cipher suites are specified in the
    OpenSSL (<http://openssl.org/docs/apps/ciphers.html>) cipherlist format,
    for example:

    ssl_ciphers ALL:!ADH:!EXPORT56:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP;

    The complete cipherlist supported by the currently installed version of
    OpenSSL in your platform can be obtained by issuing the command: openssl
    ciphers

   ssl_crl
    syntax: *ssl_crl file*

    default: *none*

    context: *tcp, server*

    This directive specifies the filename of a Certificate Revocation List,
    in PEM format, which is used to check the revocation status of
    certificates.

   ssl_prefer_server_ciphers
    syntax: *ssl_prefer_server_ciphers [on|off] *

    default: *ssl_prefer_server_ciphers off*

    context: *tcp, server*

    The server requires that the cipher suite list for protocols SSLv3 and
    TLSv1 are to be preferred over the client supported cipher suite list.

   ssl_protocols
    syntax: *ssl_protocols [SSLv2] [SSLv3] [TLSv1] [TLSv1.1] [TLSv1.2]*

    default: *ssl_protocols SSLv3 TLSv1 TLSv1.1 TLSv1.2*

    context: *tcp, server*

    This directive enables the protocol versions specified.

   ssl_verify_client
    syntax: *ssl_verify_client on|off|optional*

    default: *ssl_verify_client off*

    context: *tcp, server*

    This directive enables the verification of the client identity.
    Parameter 'optional' checks the client identity using its certificate in
    case it was made available to the server.

   ssl_verify_depth
    syntax: *ssl_verify_depth number*

    default: *ssl_verify_depth 1*

    context: *tcp, server*

    This directive sets how deep the server should go in the client provided
    certificate chain in order to verify the client identity.

   ssl_session_cache
    syntax: *ssl_session_cache off|none|builtin:size and/or
    shared:name:size*

    default: *ssl_session_cache off*

    context: *tcp, server*

    The directive sets the types and sizes of caches to store the SSL
    sessions.

    The cache types are:

    *   off -- Hard off: nginx says explicitly to a client that sessions can
        not reused.

    *   none -- Soft off: nginx says to a client that session can be resued,
        but nginx actually never reuses them. This is workaround for some
        mail clients as ssl_session_cache may be used in mail proxy as well
        as in HTTP server.

    *   builtin -- the OpenSSL builtin cache, is used inside one worker
        process only. The cache size is assigned in the number of the
        sessions. Note: there appears to be a memory fragmentation issue
        using this method, please take that into consideration when using
        this. See "References" below.

    *   shared -- the cache is shared between all worker processes. The size
        of the cache is assigned in bytes: 1 MB cache can contain roughly
        4000 sessions. Each shared cache must be given an arbitrary name. A
        shared cache with a given name can be used in several virtual hosts.

    It's possible to use both types of cache &mdash; builtin and shared
    &mdash; simultaneously, for example:

    ssl_session_cache builtin:1000 shared:SSL:10m;

    Bear in mind however, that using only shared cache, i.e., without
    builtin, should be more effective.

   ssl_session_timeout
    syntax: *ssl_session_timeout time*

    default: *ssl_session_timeout 5m*

    context: *tcp, server*

    This directive defines the maximum time during which the client can
    re-use the previously negotiated cryptographic parameters of the secure
    session that is stored in the SSL cache.

Compatibility
    *   My test bed is 0.7.65+

Notes
    The http_response_parse.rl and smtp_response_parse.rl are ragel
    (<http://www.complang.org/ragel/>) scripts , you can edit the script and
    compile it like this:

        $ ragel -G2 http_response_parse.rl
        $ ragel -G2 smtp_response_parse.rl

TODO
    *   refact this module, make it more extendable for adding third-party
        modules

    *   manipulate header like http module's proxy_set_header

    *   built-in variable support

    *   custom log format

    *   syslog support

    *   FTP/IRC proxying

Known Issues
    *   This module can't use the same listening port with the HTTP module.

Changelogs
  v0.2.0
    *   add ssl proxy module

    *   add websocket proxy module

    *   add upstream busyness module

    *   add tcp access log module

  v0.19
    *   add many check methods

  v0.1
    *   first release

Authors
    Weibin Yao(姚伟斌) *yaoweibin at gmail dot com*

Copyright & License
    This README template copy from agentzh (<http://github.com/agentzh>).

    I borrowed a lot of code from upstream and mail module from the nginx
    0.7.* core. This part of code is copyrighted by Igor Sysoev. And the
    health check part is borrowed the design of Jack Lindamood's healthcheck
    module healthcheck_nginx_upstreams
    (<http://github.com/cep21/healthcheck_nginx_upstreams>);

    This module is licensed under the BSD license.

    Copyright (C) 2013 by Weibin Yao <yaoweibin@gmail.com>.

    All rights reserved.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are
    met:

    *   Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.

    *   Redistributions in binary form must reproduce the above copyright
        notice, this list of conditions and the following disclaimer in the
        documentation and/or other materials provided with the distribution.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
    IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
    TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
    PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
    HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
    TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
    PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
    LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
    NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
    SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.