We have made 2 changes in the past that caused an unexpected edge case:
1. when faced with QUIC "no network activity", give up re-attempts and fall-back
2. when a protocol is chosen explicitly, rather than using auto (the default), do not fallback
The reasoning for 1. was to fallback quickly in situations where the user may not
have chosen QUIC, and simply got it because we auto-chose it (with the TXT DNS record),
but the users' environment does not allow egress via UDP.
The reasoning for 2. was to avoid falling back if the user explicitly chooses a
protocol. E.g., if the user chooses QUIC, she may want to do UDP proxying, so if
we fallback to HTTP2 protocol that will be unexpected since it does not support
UDP (and same applies for HTTP2 falling back to h2mux and TCP proxying).
This PR fixes the edge case that happens when both those changes 1. and 2. are
put together: when faced with a QUIC "no network activity", we should only try
to fallback if there is a possible fallback. Otherwise, we should exhaust the
retries as normal.
All header transformation code from h2mux has been consolidated in the connection package since it's used by both h2mux and http2 logic.
Exported headers used by proxying between edge and cloudflared so then can be shared by tunnel service on the edge.
Moved access-related headers to corresponding packages that have the code that sets/uses these headers.
Removed tunnel hostname tracking from h2mux since it wasn't used by anything. We will continue to set the tunnel hostname header from the edge for backward compatibilty, but it's no longer used by cloudflared.
Move bastion-related logic into carrier package, untangled dependencies between carrier, origin, and websocket packages.
- Don't rely on edge to close connection on graceful shutdown in h2mux, start muxer shutdown from cloudflared.
- Don't retry failed connections after graceful shutdown has started.
- After graceful shutdown channel is closed we stop waiting for retry timer and don't try to restart tunnel loop.
- Use readonly channel for graceful shutdown in functions that only consume the signal
Nuno Diegues
Sudarsan Reddy
Igor Postelnik
cthuang
Adam Chalmers
Areg Harutyunyan