mtp/docs/CONNECTIONS.md

MTP Connections

Native clients and hosts share the same connection shape after the opening handshake. The client creates the connection; the host receives it from accept().

Member	Native client	Native host	Web host (WebMTPConnection)
version	Compiled client version accepted by the host	Version selected by the registry	Version selected by the registry
sender	Sends CommunicationValue frames	Sends CommunicationValue frames	Sends CommunicationValue frames
receiver	Receives application frames	Receives application frames	Receives application frames
description	Optional label sent during setup	Optional label received from the client	Optional label received from the client
client_id	Confirmed or assigned ID with crypto	Authenticated or guest client ID with crypto	Authenticated or guest client ID with crypto
auth_state	Authentication result with crypto	Authentication result with crypto	Authentication result with crypto
request_path	—	—	WebTransport CONNECT path (e.g. /mtp)
remote_addr	Server SocketAddr when available	Peer SocketAddr	Peer SocketAddr

WebMTPConnection, returned by MTPWebServer::accept(), exposes the same members as the native host connection plus request_path, which contains the HTTP/3 path used for the WebTransport extended CONNECT request.

Server-side MTP connections expose remote_addr, the peer address observed by QUIC. HTTP/3 route handlers receive the same address as Http3Request::remote_addr. It is transport metadata and should not be treated as an authenticated identity; behind a proxy, use the proxy's trusted forwarding mechanism separately. The host connection also exposes a version-scoped codec and, for an authenticated client, its client_public_key. The native client connection also exposes these methods:

Method	Behavior
request	Sends a frame and waits for a response with the same frame ID, subject to request_timeout.
get_ping	Returns the latest matched protocol Ping round-trip duration.
Pipe methods	Create, accept, deny, read, write, and close native pipe streams when the pipes feature is enabled.

Connection lifecycle and keepalive behavior are defined in Protocol Reference. Pipe dispatch rules are in Pipes. Closing or dropping the connection stops its background tasks and closes the underlying QUIC session.