Quicat -- a socat-like utility for working with QUIC

This is a utility that I occasionally use for building secure-enough tunnels on flaky connections and ISPs that have TCP-breaking standards violations.

Please treat it as a pre-alpha, as it might (and probably does) contain bugs.

Usage

Usage of quicat:
quicat [flags] <src> <dst>

<src> and <dst> are either
        {stdio|stdin|stdout}
        {file-r|file-w}://<filename>
        quic-[one]{active|passive}-{listen|accept|connect|tunnel}://<hostname>:<port>
        tcp-{listen|accept|connect|tunnel}://<hostname>:<port>

'accept' is the same as 'listen', but exits after the connection is closed. 'tunnel' is the same as 'connect', but can connect multiple times.
'oneactive' is same as 'active', but exits after the connection is closed/timed out instead of listening/retrying (same with 'passive').

-ca value
        Use this CA for cert checking, can be specified multiple times
-clientca value
        Present this certificate to peers, can be specified multiple times
-dst
        Following crypto arguments will only concern second (dst) argument URI
-insecure
        Insecure, don't check remote cert validity. Vulnerable to MITM.
-keypair value
        Certificate/key pair in a single PEM-encoded file
-next-proto string
        Specify TLS next proto, 'raw' or 'raw-sig' (-streamsig) by default
-quiet
        Don't print errors to stderr
-retry-delay int
        When positive, retry connections, inserting a delay (in ms) between each retry (default -1)
-signalstream
        Signal streams by sending a (zero) character in a stream that just opened (default true)
-simultaneous
        Attempt connections to src and dst at the same time
-src
        Following crypto arguments will only concern first (src) argument URI

Known issues

• quicat only supports a single QUIC session at a time. Until several dispatching strategies are implemented, this is by design. Wait for the QUIC session to timeout or send an application error to it before connecting again.