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.
42 lines
944 B
C++
42 lines
944 B
C++
#pragma once
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#include "screencast/network/error.h"
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#include <cstdint>
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#include <functional>
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#include <memory>
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#include <string>
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namespace sc {
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struct DiscoveredPeer {
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std::string service_name;
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std::string host;
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uint16_t signaling_port = 0;
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};
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class DiscoveryService {
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public:
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using PeerCallback = std::function<void(const DiscoveredPeer&)>;
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virtual ~DiscoveryService() = default;
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// Announce this peer on the LAN.
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virtual bool announce(const std::string& service_name, uint16_t signaling_port) = 0;
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// Browse for peers; callback is invoked for each newly found service.
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virtual bool browse(PeerCallback on_peer) = 0;
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virtual void stop() = 0;
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// Diagnostic message from the last failure (empty if none).
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virtual std::string last_error() const = 0;
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};
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class DiscoveryFactory {
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public:
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static NetworkResult<std::unique_ptr<DiscoveryService>> create_avahi();
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};
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} // namespace sc
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