v811_spc009/external/libwebsockets/minimal-examples/raw/minimal-raw-proxy-fallback

lws minimal ws server raw proxy fallback

This demonstrates how a vhost doing normal http or http(s) duty can be also be bound to a specific role and protocol as a fallback if the incoming protocol is unexpected for tls or http. The example makes the fallback role + protocol an lws plugin that performs raw packet proxying.

By default the fallback in the example will proxy 127.0.0.1:22, which is usually your ssh server listen port, on 127.0.0.1:7681. You should be able to ssh into port 7681 the same as you can port 22. At the same time, you should be able to visit http://127.0.0.1:7681 in a browser (and if you give -s, to https://127.0.0.1:7681 while your ssh client can still connect to the same port.

build

To build this standalone, you must tell cmake where the lws source tree ./plugins directory can be found, since it relies on including the source of the raw-proxy plugin.

 $ cmake . -DLWS_PLUGINS_DIR=~/libwebsockets/plugins && make

usage

Commandline option	Meaning
-d	Debug verbosity in decimal, eg, -d15
-r ipv4:address:port	Configure the remote IP and port that will be proxied, by default ipv4:127.0.0.1:22
-s	Configure the server for tls / https and LWS_SERVER_OPTION_ALLOW_NON_SSL_ON_SSL_PORT
-h	(needs -s) Configure the vhost also for LWS_SERVER_OPTION_ALLOW_HTTP_ON_HTTPS_LISTENER, allowing http service on tls port (caution... it's insecure then)
-u	(needs -s) Configure the vhost also for LWS_SERVER_OPTION_REDIRECT_HTTP_TO_HTTPS, so the server issues a redirect to https to clients that attempt to connect to a server configured for tls with http.

 $ ./lws-minimal-raw-proxy
[2018/11/30 19:22:35:7290] USER: LWS minimal raw proxy-fallback
[2018/11/30 19:22:35:7291] NOTICE: Creating Vhost 'default' port 7681, 1 protocols, IPv6 off
[2018/11/30 19:22:35:7336] NOTICE: callback_raw_proxy: onward ipv4 127.0.0.1:22
...

 $ ssh -p7681 me@127.0.0.1
Last login: Fri Nov 30 19:29:23 2018 from 127.0.0.1
[me@learn ~]$

At the same time, visiting http(s)://127.0.0.1:7681 in a browser works fine.