sgateway

Simple Gateway — a raw TCP relay. It listens on an input URL, dials out to an output URL, and forwards bytes verbatim in both directions. Useful for tunnelling or exposing a backend endpoint through a controlled front.

Architecture¶

Two symmetric sides, each a C_IOGATE > C_CHANNEL > C_PROT_RAW > C_TCP stack:

              input_url (listen)                    output_url (connect)
client  ───▶  __input_side__  ──▶  C_SGATEWAY  ──▶  __output_side__  ───▶  upstream
        ◀───                  ◀──             ◀──                    ◀───

• Input side (__input_side__): a TCP server bound to input_url, accepting client connections.

• Output side (__output_side__): a TCP client that connects to output_url (reconnecting every 100 ms).

• C_PROT_RAW carries the payload, so bytes pass through untouched — there is no framing, parsing, or protocol awareness.

• C_SGATEWAY relays EV_ON_MESSAGE: bytes from the input side are sent to the output side and vice-versa.

TLS is selected by the URL scheme (tcps:// for either side); tcp:// is plain. Because the relay is byte-transparent it bridges any TCP-based protocol.

Configuration¶

Both URLs are required; at play time, if either is empty the yuno logs an error and pauses itself.

input_url / output_url are writable and persisted. Set them through the agent, then (re)play the yuno:

ycommand command-yuno id=<id> service=__root__ command=write-str attribute=input_url  value=tcp://0.0.0.0:2011
ycommand command-yuno id=<id> service=__root__ command=write-str attribute=output_url value=tcp://10.0.0.5:2012

Throughput stats¶

Exposed as reset-on-read stats (SDF_RSTATS): rxMsgs, txMsgs, and the per-second gauges rxMsgsec / txMsgsec with their high-water marks maxrxMsgsec / maxtxMsgsec (recomputed on each timeout tick).

Commands¶

(The gateway is configured through attributes, not commands.)

Debugging¶

sgateway enables C_TCP connections and C_TCP_S listen/accepted/ not-accepted by default. Enable more with ycommand command-yuno id=<id> service=__yuno__ command=set-gclass-trace gclass=<G> set=1 level=<L>.