https://github.com/warmcat/libwebsockets/issues/1423
If you vhost->options has the flag LWS_SERVER_OPTION_VHOST_UPG_STRICT_HOST_CHECK,
then if the server is sent an upgrade request, the content of the Host: header is
required to match the vhost name + port. The port is set to the well-known values
of 80 and 443 if no :port on the host: value, depending on tls or not on the
connection.
minimal-ws-server can now take a -h flag to set this. lejp-conf (eg, lwsws) can now take
a flag strict-host-check on the vhost to enable it as well.
Since new roles may be incompatible with http, add support for
alpn names at the role struct, automatic generation of the
default list of alpn names that servers advertise, and the
ability to override the used alpn names per-vhost and per-
client connection.
This not only lets you modulate visibility or use of h2,
but also enables vhosts that only offer non-http roles,
as well as restricting http role vhosts to only alpn
identifiers related to http roles.
