fegger
7be8d59d07
Add mDNS/DNS-SD discovery and JSON session negotiation so two peers on a LAN connect without hard-coded addresses. - Discovery (Avahi threaded-poll client): the receiver announces _screencast._tcp with its signaling port; senders browse and resolve peers. Strict lock ordering (poll lock before state mutex) keeps the callbacks deadlock-free; name collisions rename via avahi_alternative_service_name. - Signaling: one JSON object per newline-terminated TCP line. The receiver hosts a server (port 5005) and answers session offers with its RTP port; senders connect, offer, and stream to the negotiated endpoint. WebSocket was deferred: no WS library is installed, the skill permits plain TCP, and the wire format is transport-agnostic. - Dual-stack transports: this machine resolves its own services over IPv6, so getaddrinfo now runs AF_UNSPEC and listeners bind IPv6 with IPV6_V6ONLY=0 (IPv4 fallback), covering UDP and TCP alike. The signaling client shutdown now uses shutdown() so a reader blocked in recv() cannot hang the join (a plain close() does not wake it). - CLI: --discover lists receivers (deduped to one entry per host); --send auto-disovers when exactly one receiver is found; --peer targets a receiver directly; --signaling-port overrides the default. Validation: meson test 5/5 (new signaling round-trip test), valgrind clean. End-to-end over loopback: --discover finds the announced receiver, a probe negotiated a session and streamed 60 frames over both IPv4 and IPv6, and the receiver reported stream started. mDNS resolution was verified against avahi-browse as an independent reference.
37 lines
980 B
C++
37 lines
980 B
C++
#pragma once
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#include <string>
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#include <variant>
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namespace sc {
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struct NetworkError {
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std::string message;
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};
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// C++20 does not provide std::expected. Use a variant-based result type so
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// fallible network operations do not rely on exceptions.
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template <typename T> using NetworkResult = std::variant<T, NetworkError>;
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template <typename T> constexpr bool is_network_error(const NetworkResult<T>& result) noexcept {
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return std::holds_alternative<NetworkError>(result);
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}
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template <typename T> T& network_value(NetworkResult<T>& result) {
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return std::get<T>(result);
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}
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template <typename T> const T& network_value(const NetworkResult<T>& result) {
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return std::get<T>(result);
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}
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template <typename T> NetworkError& network_error(NetworkResult<T>& result) {
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return std::get<NetworkError>(result);
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}
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template <typename T> const NetworkError& network_error(const NetworkResult<T>& result) {
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return std::get<NetworkError>(result);
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}
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} // namespace sc
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