From 2d010c9f851ea4eb851179db012c8977ce6e4bd5 Mon Sep 17 00:00:00 2001
From: srdusr <99972264+srdusr@users.noreply.github.com>
Date: Wed, 19 Nov 2025 21:18:00 +0200
Subject: Add RTP/RTCP as a labeled heuristic fallback for unmatched UDP
 traffic

Architecturally different from every other protocol added so far: RTP
has no fixed well-known port at all - it's negotiated per call via
SDP/SIP/WebRTC signaling this project doesn't parse - so L7Registry's
port-keyed dispatch doesn't apply. Handled instead as a fallback tried
only when a UDP packet's normal port-based lookup finds nothing, with
every match labeled "?" (e.g. "RTCP? SR") to mark it as inferred from
packet shape rather than certain - the same honesty Wireshark itself
applies to heuristic dissection, which is off by default there for
exactly this reason.

The two heuristics aren't equally trusted, and the code says so: RTCP
checks a narrow packet-type range (200-204) plus an exact self-declared
length, both unlikely to occur by chance; RTP leans mostly on the 2-bit
version field, since its other structural checks are trivially
satisfied whenever those bits happen to be zero, the common case even
for unrelated traffic. Shipped anyway - a labeled guess on real
RTP/RTCP traffic is more useful than silence - but this is the first
place in the project where a match doesn't mean certainty.

Live-verified against genuine media traffic: ffmpeg streaming a real
RTP video test pattern to loopback, correctly decoded with incrementing
sequence numbers and a consistent SSRC across the stream, plus a real
RTCP Sender Report ffmpeg sent alongside it.
---
 CMakeLists.txt | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'CMakeLists.txt')

diff --git a/CMakeLists.txt b/CMakeLists.txt
index b7fab04..20fc70e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -99,6 +99,8 @@ add_executable(packeteer_tests
   tests/test_net.cpp
   tests/test_arp.cpp
   tests/test_igmp.cpp
+  tests/test_rtcp.cpp
+  tests/test_rtp.cpp
   tests/test_ipv6.cpp
   tests/test_dns.cpp
   tests/test_mdns.cpp
-- 
cgit v1.2.3