fatedier/frp

The repo builds two binaries from a single Go module: frps (server, cmd/frps) and frpc (client, cmd/frpc), both driven by cobra. server/service.go constructs a Service that multiplexes control-plane listeners (TCP mux, KCP, QUIC, WebSocket, raw TLS, internal SSH pipe) on shared ports and owns the ControlManager, proxy.Manager, plugin.Manager, ports.Manager and vhost routers. client/service.go constructs a Service that dials frps through a pluggable Connector and keeps a Control session alive with backoff retries. Shared protocol and config code lives under pkg/ (msg, proto/wire, config/v1, auth, transport, util). State is entirely in-memory except an optional client-side JSON store for dynamic proxies. Two Vue 3 apps under web/ provide dashboards and are embedded via the assets package, or excluded with the 'noweb' build tag.

• frps entrypoint is cmd/frps/root.go: cobra rootCmd.RunE loads config via config.LoadServerConfig, validates with validation.NewConfigValidator, then calls runServer -> server.NewService -> svr.Run.
  cmd/frps/root.go#L53-127server/service.go#L139
• frpc entrypoint is cmd/frpc/sub/root.go: runClient -> config.LoadClientConfigResult -> source.NewAggregator -> client.NewService -> svr.Run; a --config_dir flag runs one Service per file via runMultipleClients.
  cmd/frpc/sub/root.go#L59-134client/service.go#L163
• server.Service multiplexes the bind port with golib mux.Mux: default listener for TCP control, a prefix-matched websocket listener ('GET /~frp'), and a TLS listener that sniffs first byte 0x16 / FRPTLSHeadByte.
  server/service.go#L245-253server/service.go#L290-294server/service.go#L352-355
• Optional listeners are created for KCP (netpkg.ListenKcp on KCPBindPort), QUIC (quic.ListenAddr with ALPN 'frp'), SSH tunnel gateway (ssh.NewGateway), and a tcpmux HTTPConnect multiplexer on TCPMuxHTTPConnectPort.
  server/service.go#L256-287server/service.go#L191-204pkg/ssh/gateway.go
• The wire protocol has two versions: acceptConnection calls wire.CheckMagic to detect v2, then negotiates crypto/UDP-codec via ClientHello/ServerHello frames before reading the first msg.
  server/service.go#L555-593server/service.go#L623-680pkg/proto/wire
• The client dials frps through a Connector interface (client/connector.go) supporting tcp, kcp, quic (one quic.Conn, streams converted via QuicStreamToNetConn), websocket/wss, and tls; ServiceOptions.ConnectorCreator allows swapping in a virtual pipe connector.
  client/connector.go#L33-60client/connector.go#L104-137client/connector.go#L216-226client/service.go#L83-90
• Server state is in-memory: registry.ClientRegistry tracks logical clients by user.clientID, proxy.Manager tracks live proxies, ports.Manager allocates TCP/UDP remote ports honoring AllowPorts, and vhost.Routers route HTTP(S) vhosts.
  server/service.go#L167-180server/registryserver/ports/ports.gopkg/util/vhost
• The only persistent state is the optional client-side StoreSource: a JSON file (store.path) holding dynamic proxies/visitors, merged with file config by source.Aggregator.
  pkg/config/source/store.gopkg/config/source/aggregator.gocmd/frpc/sub/root.go#L143-163
• Dashboards are Vue 3 apps web/frps and web/frpc (npm workspaces under web/), embedded into Go via the assets package; Makefile adds a 'noweb' build tag when web/*/dist is absent.
  web/package.jsonassets/assets.goMakefile#L4web/frps/package.jsonweb/frpc/package.json
• Build produces CGO_ENABLED=0 binaries with build tags 'frps'/'frpc' plus optional 'noweb' (Makefile frps/frpc targets); go.mod pins go 1.25.0 with quic-go, kcp-go, yamux, gorilla/mux, go-oidc, prometheus, wireguard as key deps.
  Makefile#L40-44go.mod#L3-39
• server/http and client/http packages implement admin API controllers behind gorilla/mux routers registered by registerRouteHandlers on each Service's webServer (httppkg.Server).
  server/api_router.go#L27-71client/api_router.go#L26-64server/httpclient/http
• Both services disable quic-go receive-buffer warnings and ECN via env vars in package init, and set crypto.DefaultSalt = 'frp' for golib crypto.
  server/service.go#L70-78client/service.go#L47-55