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sniproxy: SNI Proxy based on stream-lua-nginx-module

Installation

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CentOS/RHEL 7 or Amazon Linux 2

yum -y install https://extras.getpagespeed.com/release-latest.rpm
yum -y install lua-resty-sniproxy

CentOS/RHEL 8+, Fedora Linux, Amazon Linux 2023

yum -y install https://extras.getpagespeed.com/release-latest.rpm
yum -y install lua5.1-resty-sniproxy

To use this Lua library with NGINX, ensure that nginx-module-lua is installed.

This document describes lua-resty-sniproxy v0.22 released on Aug 31 2020.

lua-resty-sniproxy - SNI Proxy based on the ngx_lua cosocket API

Description

This library is an SNI proxy written in Lua. TLS parsing part is rewritten from dlundquist/sniproxy

Note that nginx stream module and ngx_stream_lua_module is required.

Tested on Openresty >= 1.9.15.1.

Status

Experimental.

Synopsis

stream {
    init_by_lua_block {
        local sni = require("resty.sniproxy")
        sni.rules = { 
            {"www.google.com", "www.google.com", 443},
            {"www.facebook.com", "9.8.7.6", 443},
            {"api.twitter.com", "1.2.3.4"},
            {".+.twitter.com", nil, 443},
            -- to activate this rule, you must use Lua land proxying
            -- {"some.service.svc", "unix:/var/run/nginx-proxy-proto.sock", nil, sni.SNI_PROXY_PROTOCOL_UPSTREAM},
            -- {"some2.service.svc", "unix:/var/run/nginx-proxy-proto.sock", nil,
            --                            sni.SNI_PROXY_PROTOCOL_UPSTREAM + sni.SNI_PROXY_PROTOCOL},
            {".", "unix:/var/run/nginx-default.sock"}
        }   
    }

    # for OpenResty >= 1.13.6.1, native Nginx proxying
    lua_add_variable $sniproxy_upstream;
    server {
            error_log /var/log/nginx/sniproxy-error.log error;
            listen 443;

            resolver 8.8.8.8;

            prepread_by_lua_block {
                    local sni = require("resty.sniproxy")
                    local sp = sni:new()
                    sp:preread_by()
            }
            proxy_pass $sniproxy_upstream;
    }

    # for OpenResty < 1.13.6.1 or `flags` are configured, Lua land proxying
    server {
            error_log /var/log/nginx/sniproxy-error.log error;
            listen 443;

            resolver 8.8.8.8;

            content_by_lua_block {
                    local sni = require("resty.sniproxy")
                    local sp = sni:new()
                    sp:content_by()
            }
    }
}

A Lua array table sni_rules should be defined in the init_worker_by_lua_block directive.

The first value can be either whole host name or regular expression. Use . for a default host name. If no entry is matched, connection will be closed.

The second and third values are target host name and port. A host can be DNS name, IP address or UNIX domain socket path. If host is not defined or set to nil, server_name in SNI will be used. If the port is not defined or set to nil , 443 will be used.

The forth value is the flags to use. Available flags are:

    sni.SNI_PROXY_PROTOCOL -- use client address received from proxy protocol to send to upstream
    sni.SNI_PROXY_PROTOCOL_UPSTREAM -- send proxy protocol v1 handshake to upstream

To use flags, the server must be configured to do Lua land proxying (see above example).

Rules are applied with the priority as its occurrence sequence in the table. In the example above, api.twitter.com will match the third rule api.twitter.com rather than the fourth .+.twitter.com.

If the protocol version is less than TLSv1 (eg. SSLv3, SSLv2), connection will be closed, since SNI extension is not supported in these versions.

See Also

GitHub

You may find additional configuration tips and documentation for this module in the GitHub repository for nginx-module-sniproxy.