1772212 - Improve dispatching transactions on tunnel through a HTTP/2 proxy

Status: RESOLVED FIXED

(Core :: Networking: HTTP, task, P3)

Description

[Dragana Damjanovic [:dragana]]

Current state:

The browser limits the number of parallel connections to an origin. nsHttpConnectionMgr is responsible for this for all HTTP requests and all HTTP requests through a non HTTP/2 proxy. In the case of the HTTP/2 proxy, the Http2Session is responsible for this which not only duplicates functionalities but also adds unnecessary complexity (e.g. if there is space for more connection because a CONNECT stream was closed a separate triggering mechanism is needed).
Additional complexity is that the CONNECT request is driven in 2 ways at the moment:

• In the case of HTTP/1.1 proxy: nsHttpConnection is responsible for driving the CONNECT request
• In the case of HTTP/2 proxy: Http2ConnectTransaction drives the CONNECT request.

Proposal

When a new nsHttpTransaction that should be sent through a proxy needs to be dispatched do the following:

• Check if there is a HTTP/2 connection to the origin that goes through the HTTP/2 proxy. If there is one and it can accept new streams, dispatch the transaction.
• Check if the connection limit for the connection to an origin though the proxy is reached(there cannot be more than 6 connections to origin x that go through proxy y). If this is true, add the transaction to the pending queue.
• If there is a HTTP/2 connection to the proxy:
  • Create Http2StreamConnention (see 1772205)
  • Create a nsHttpConnection object for the connection through the proxy and register it to the nsHttpConnectionMgr. The nsHttpConnection will use Http2StreamConnention as nsISocketTransport and Http2StreamConnectionOutputStream and Http2StreamConnectionInputStream as nsSocketInoput/OutputStream.
  • Dispatch the transaction to the nsHttpConnection.
  • The nsHttpConnection will be responsible for driving CONNECT request.
• If there is no HTTP/2 connection to the proxy, create a new connection to the proxy in the same way it is don now for HTTP/1.1 and HTTP/2 proxies.

Comment 1

[Kershaw Chang [:kershaw]]

Attachment: Bug 1772212 - Check connection limit before dispatch a transaction thourgh Http/2 proxy, r=#necko

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/1e2092c319eb
Check connection limit before dispatch a transaction thourgh Http/2 proxy, r=necko-reviewers,dragana

Comment 3

[Norisz Fay [:noriszfay]]

https://hg.mozilla.org/mozilla-central/rev/1e2092c319eb