Crate volto 

Volto — a MASQUE proxy server.

Volto terminates HTTP/3 over QUIC and proxies client traffic:

• TCP via classic CONNECT tunnels (RFC 9114 §4.4).
• UDP via CONNECT-UDP (RFC 9298) + HTTP Datagrams (RFC 9297).

Module layout

• auth — HTTP Basic authentication of CONNECT requests.
• config — TOML configuration and its validation.
• policy — the destination ACL: which targets may be reached.
• tls — certificate/key loading and the rustls server configuration.
• gate — the SNI gate: which handshakes reach quinn at all.
• quic — the QUIC endpoint, transport parameters and the accept loop.
• shutdown — the graceful-shutdown signal shared by endpoint and connections.
• h3 — HTTP/3 (RFC 9114) for a proxy: framing, QPACK, the control stream, request streams, and the routing of inbound HTTP Datagrams to the stream each one names.
• h3api — the facade over that layer, and the only HTTP/3 vocabulary the rest of the crate uses.
• conn — per-connection driving and request dispatch.
• capsule — the Capsule Protocol (RFC 9297 §3) incremental decoder.
• datagram — HTTP Datagram payload coding (RFC 9297) and QUIC varints.
• net — explicit name resolution and UDP socket setup.
• logfmt — how an optional value is spelled in a log field.
• tunnel — request routing, the per-connection context and the tunnels.

Security status

Requests are authenticated (auth) and destinations are filtered (policy) — but both are configuration-dependent, and the defaults are not the safe ones in the same way everywhere:

• an empty [auth].users disables authentication, making this an open proxy. config::Config::warnings says so at startup, and it is the intended state only while debugging interop on a private network;
• [security] defaults are the safe ones: private address space is out of reach, port 25 is closed, and an unanswered UDP session cannot be used as an amplifier — with one deliberate exception, expected_sni, whose default empty list leaves the port answering anybody who speaks QUIC to it, because turning the gate on without knowing the name is a server nobody can reach.

Modules

auth

HTTP Basic authentication (RFC 7617) for CONNECT requests.

capsule

The Capsule Protocol (RFC 9297 §3).

config

Configuration file loading and validation.

conn

Per-connection driving: accept request streams, authenticate them, dispatch them.

datagram

HTTP Datagram payload coding (RFC 9297) and QUIC varints (RFC 9000 §16).

gate

The SNI gate: which handshakes are allowed to reach quinn at all.

h3

HTTP/3 (RFC 9114) for a proxy, implemented in the tree.

h3api

The facade over the HTTP/3 layer.

logfmt

Formatting helpers for log fields.

net

Socket helpers: name resolution and UDP socket setup.

policy

Destination policy: which targets this proxy is willing to reach.

quic

The QUIC endpoint: transport parameters, the accept loop and peer metadata.

shutdown

The shutdown signal, from the process down to each connection.

tls

TLS identity: certificate/key loading and the rustls server configuration.

tunnel

Request routing, the per-connection context, and the tunnel implementations.