Corrects the pattern of using errgroup's and context cancellation to simplify the logic for canceling extra routines for the QUIC connection. This is because the extra context cancellation is redundant with the fact that the errgroup also cancels it's own provided context when a routine returns (error or not).
For the datagram handler specifically, since it can respond faster to a context cancellation from the QUIC connection, we wrap the error before surfacing it outside of the QUIC connection scope to the supervisor. Additionally, the supervisor will look for this error type to check if it should retry the QUIC connection. These two operations are required because the supervisor does not look for a context canceled error when deciding to retry a connection. If a context canceled from the datagram handler were to be returned up to the supervisor on the initial connection, the cloudflared application would exit. We want to ensure that cloudflared maintains connection attempts even if any of the services on-top of a QUIC connection fail (datagram handler in this case).
Additional logging is also introduced along these paths to help with understanding the error conditions from the specific handlers on-top of a QUIC connection.
Related CUSTESC-53681
Closes TUN-9610
Make sure to enforce snapshots of features and client information for each connection
so that the feature information can change in the background. This allows for new features
to only be applied to a connection if it completely disconnects and attempts a reconnect.
Updates the feature refresh time to 1 hour from previous cloudflared versions which
refreshed every 6 hours.
Closes TUN-9319
During a refresh of the supported features via the DNS TXT record,
cloudflared would update the internal feature list, but would not
propagate this information to the edge during a new connection.
This meant that a situation could occur in which cloudflared would
think that the client's connection could support datagram V3, and
would setup that muxer locally, but would not propagate that information
to the edge during a register connection in the `ClientInfo` of the
`ConnectionOptions`. This meant that the edge still thought that the
client was setup to support datagram V2 and since the protocols are
not backwards compatible, the local muxer for datagram V3 would reject
the incoming RPC calls.
To address this, the feature list will be fetched only once during
client bootstrapping and will persist as-is until the client is restarted.
This helps reduce the complexity involved with different connections
having possibly different sets of features when connecting to the edge.
The features will now be tied to the client and never diverge across
connections.
Also, retires the use of `support_datagram_v3` in-favor of
`support_datagram_v3_1` to reduce the risk of reusing the feature key.
The `dv3` TXT feature key is also deprecated.
Closes TUN-9291
## Summary
This commit renames the public variable that identifies the metadata key and value for the ConnectResponse structure when the flow was rate limited.
Closes TUN-8904
## Summary
Session is the concept used for UDP flows. Therefore, to make
the session limiter ambiguous for both TCP and UDP, this commit
renames it to flow limiter.
Closes TUN-8861
## Summary
In order to make cloudflared behavior more predictable and
prevent an exhaustion of resources, we have decided to add
session limits that can be configured by the user. This commit
adds the session limiter to the HTTP/TCP handling path.
For now the limiter is set to run only in unlimited mode.
A new ICMPResponder interface is introduced to provide different
implementations of how the ICMP flows should return to the QUIC
connection muxer.
Improves usages of netip.AddrPort to leverage the embedded zone
field for IPv6 addresses.
Closes TUN-8640
The current supervisor serves the quic connection by performing all of the following in one method:
1. Dial QUIC edge connection
2. Initialize datagram muxer for UDP sessions and ICMP
3. Wrap all together in a single struct to serve the process loops
In an effort to better support modularity, each of these steps were broken out into their own separate methods that the supervisor will compose together to create the TunnelConnection and run its `Serve` method.
This also provides us with the capability to better interchange the functionality supported by the datagram session manager in the future with a new mechanism.
Closes TUN-8661
Devin Carr
Luis Neto
João "Pisco" Fernandes