GEP: Enable or disable HTTP/3 of a host

[lianglli]

What would you like to be added:
A specific config for enable/disable HTTP/3 of a host.

Why this is needed:
Most browsers have support HTTP/3. However, if the server (host) supports HTTP/3, it will return response header Alt-Svc with h3 protocol, listen port and fresh time specifically.

Based on ResponseHeaderModifier for enable HTTP/3 of a host, HTTPRoute owner need to get h3 protocol (E.g., h3 and h3-29) and h3 listening port of the gateway specifically.

Hence, It's better to have a HTTPRoute config for enable/disable HTTP/3 of a host.

[howardjohn]

High level comment - controlling this at HTTPRoute exclusively feels wrong, since it requires a dedicated udp listener which implies (to me) Gateway listener enablement. Maybe then also route level

[youngnick]

Agreed, this cannot be only at the HTTPRoute level, as it requires a HTTP3 listener at the Gateway level. At a minimum, this requires defining a HTTP3 Protocol in the Listener, and then which Routes would work with it (presumably only HTTPRoute, but we need to be specific).

[lianglli]

It accepts HTTP/1.1 or HTTP/2 or HTTP/3.

	HTTPSProtocolType ProtocolType = "HTTPS"

The HTTP/1.1 or HTTP/2 is built on top of TCP.
The HTTP/3 is built on top of UDP.

With the gateway api context, when you create a https-listener with protocol: HTTPS, you do NOT need to add a tcp listener or udp listener anymore.

However, when the gateway implementation supports http/3 (quic), the gateway will listen on 443 tcp and 443 udp.
And, the config of gateway runtime will add protocol quic to the listener 443 port.

        listen 443 default_server reuseport backlog=65535 ssl http2;
        listen [::]:443 default_server reuseport backlog=65535 ssl http2;
        listen 443 default_server reuseport backlog=65535 xquic sndbuf=5242880 rcvbuf=5242880 ;
        listen [::]:443 default_server reuseport backlog=65535 xquic sndbuf=5242880 rcvbuf=5242880 ;

This GEP is used to add a specific config for enable/disable HTTP/3 of a hostname.

Most browsers have support HTTP/3.
However, if the server (hostname) supports HTTP/3, it will return response header Alt-Svc with h3 protocol, listen port and fresh time specifically.

It's better to have a HTTPRoute config for enable/disable HTTP/3 of a hostname.

E.g.,

curl -i https://tengine.taobao.org/
HTTP/2 200 

alt-svc: h3=":443"; ma=2592000,h3-29=":443"; ma=2592000

[youngnick]

Having one listener listen on two ports (TCP and UDP) does not fit with our existing Listener semantics, which map one port/protocol combination to one Listener.

"HTTPS" protocol current implies TCP Protocol, with TLS, and terminated HTTP.

So, changing that by adding HTTP3 to the mix is actually a bigger change than it would seem.

I don't think that we can skip at least some Listener updates, although I see the point that most people wanting to do HTTP3 UDP listeners will also want to do HTTP2 listeners on the equivalent TCP port.

But that sort of implicit, magic behavior (one Listener == two ports) is exactly the sort of thing we're trying to avoid with Gateway API. Less magic behavior!

[howardjohn]

I don't think it's impossible to have a single Gateway listener with a protocol or other option that implies "udp + tcp" though we could also make users use 2 listeners.
Having 2 listeners also implies the ability to have different routes for each, which may be desired (flexible) or not (may break some implementations and cause complexity).

I believe in Istio we have a single HTTP3 protocol that implies 1+2+3

[lianglli]

The "HTTPS" protocol should include HTTP/1, HTTP/2 and HTTP/3 (maybe HTTP/4 in future).

The HTTP/3 is built on top of UDP with TLSv1.3 by default.
So, if there is a Listener with "HTTPS" protocol of gateway API, the "HTTPS" Listener will accept HTTP/1, HTTP/2 and HTTP/3.

When the gateway implementation supports http/3 (quic), the gateway will listen on 443 TCP for HTTP/1 and HTTP/2 and 443 UDP for HTTP/3 on runtime.

For example (Tengine):
Listen on IPv4 and IPv6 with TCP port 443 for HTTP/1 and HTTP/2 over TLSv1 TLSv1.1 TLSv1.2 TLSv1.3

        listen 443 default_server reuseport backlog=65535 ssl http2;
        listen [::]:443 default_server reuseport backlog=65535 ssl http2;

Listen on IPv4 and IPv6 with UDP port 443 for HTTP/3 (quic) over TLSv1.3

        listen 443 default_server reuseport backlog=65535 xquic sndbuf=5242880 rcvbuf=5242880 ;
        listen [::]:443 default_server reuseport backlog=65535 xquic sndbuf=5242880 rcvbuf=5242880 ;

This GEP is used to add a config for enable / disable HTTP/3 for a hostname based on HTTPRoute.

HTTP/3 is discovered as an upgrade from HTTP/1.1 or HTTP/2 via the response header Alt-Svc header. That means the first request will normally use HTTP/1.1 or HTTP/2 before switching to HTTP/3.

If a HTTPRoute with hostname enabled the HTTP/3, the gateway implementation will automatically add response header Alt-Svc with h3 protocol, listen port and fresh time for this hostname specifically.

Then, the client (E.g., chrome browser) will use HTTP/3 protocol for communication with this host (domain) after the first request.

As an upstream application server, it has not knowledge about h3 protocol, listen port and fresh time for the response header Alt-Svc.

Hence, this is a basic feature for the "HTTPS" protocol of Gateway API.