From a6075db4ba2cf23e50136aa51fa577fb590ca0b6 Mon Sep 17 00:00:00 2001
From: hayzam <hayzam@difuse.io>
Date: Wed, 11 Feb 2026 15:36:05 +0530
Subject: [PATCH] analyzer: make http3/quic handling more reliable

---
 analyzer/udp/quic.go      |  5 -----
 analyzer/udp/quic_test.go | 38 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+), 5 deletions(-)

diff --git a/analyzer/udp/quic.go b/analyzer/udp/quic.go
index 1e02313..dae90e5 100644
--- a/analyzer/udp/quic.go
+++ b/analyzer/udp/quic.go
@@ -49,11 +49,6 @@ func (s *quicStream) Feed(rev bool, data []byte) (u *analyzer.PropUpdate, done b
 	//   + compression methods (2 bytes) + no extensions
 	const minDataSize = 41
 
-	if rev {
-		// Ignore server direction; we only parse client initial data.
-		return nil, false
-	}
-
 	frs, err := quic.ReadCryptoFrames(data)
 	if err != nil || len(frs) == 0 {
 		s.invalidCount++
diff --git a/analyzer/udp/quic_test.go b/analyzer/udp/quic_test.go
index 2421e3d..fad1e1f 100644
--- a/analyzer/udp/quic_test.go
+++ b/analyzer/udp/quic_test.go
@@ -66,3 +66,41 @@ func TestQuicStreamContiguousPayloadFromZero(t *testing.T) {
 		t.Fatalf("contiguousPayloadFromZero() = %q, want %q", string(got), "abcde")
 	}
 }
+
+func TestQuicStreamParsing_ClientHelloReverseDirection(t *testing.T) {
+	// same packet as TestQuicStreamParsing_ClientHello, but feed as rev=true
+	clientHello := make([]byte, 1200)
+	clientInitial := []byte{
+		0xcd, 0x00, 0x00, 0x00, 0x01, 0x08, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05,
+		0x06, 0x07, 0x05, 0x63, 0x5f, 0x63, 0x69, 0x64, 0x00, 0x41, 0x03, 0x98,
+		0x1c, 0x36, 0xa7, 0xed, 0x78, 0x71, 0x6b, 0xe9, 0x71, 0x1b, 0xa4, 0x98,
+		0xb7, 0xed, 0x86, 0x84, 0x43, 0xbb, 0x2e, 0x0c, 0x51, 0x4d, 0x4d, 0x84,
+		0x8e, 0xad, 0xcc, 0x7a, 0x00, 0xd2, 0x5c, 0xe9, 0xf9, 0xaf, 0xa4, 0x83,
+		0x97, 0x80, 0x88, 0xde, 0x83, 0x6b, 0xe6, 0x8c, 0x0b, 0x32, 0xa2, 0x45,
+		0x95, 0xd7, 0x81, 0x3e, 0xa5, 0x41, 0x4a, 0x91, 0x99, 0x32, 0x9a, 0x6d,
+		0x9f, 0x7f, 0x76, 0x0d, 0xd8, 0xbb, 0x24, 0x9b, 0xf3, 0xf5, 0x3d, 0x9a,
+		0x77, 0xfb, 0xb7, 0xb3, 0x95, 0xb8, 0xd6, 0x6d, 0x78, 0x79, 0xa5, 0x1f,
+		0xe5, 0x9e, 0xf9, 0x60, 0x1f, 0x79, 0x99, 0x8e, 0xb3, 0x56, 0x8e, 0x1f,
+		0xdc, 0x78, 0x9f, 0x64, 0x0a, 0xca, 0xb3, 0x85, 0x8a, 0x82, 0xef, 0x29,
+		0x30, 0xfa, 0x5c, 0xe1, 0x4b, 0x5b, 0x9e, 0xa0, 0xbd, 0xb2, 0x9f, 0x45,
+		0x72, 0xda, 0x85, 0xaa, 0x3d, 0xef, 0x39, 0xb7, 0xef, 0xaf, 0xff, 0xa0,
+		0x74, 0xb9, 0x26, 0x70, 0x70, 0xd5, 0x0b, 0x5d, 0x07, 0x84, 0x2e, 0x49,
+		0xbb, 0xa3, 0xbc, 0x78, 0x7f, 0xf2, 0x95, 0xd6, 0xae, 0x3b, 0x51, 0x43,
+		0x05, 0xf1, 0x02, 0xaf, 0xe5, 0xa0, 0x47, 0xb3, 0xfb, 0x4c, 0x99, 0xeb,
+		0x92, 0xa2, 0x74, 0xd2, 0x44, 0xd6, 0x04, 0x92, 0xc0, 0xe2, 0xe6, 0xe2,
+		0x12, 0xce, 0xf0, 0xf9, 0xe3, 0xf6, 0x2e, 0xfd, 0x09, 0x55, 0xe7, 0x1c,
+		0x76, 0x8a, 0xa6, 0xbb, 0x3c, 0xd8, 0x0b, 0xbb, 0x37, 0x55, 0xc8, 0xb7,
+		0xeb, 0xee, 0x32, 0x71, 0x2f, 0x40, 0xf2, 0x24, 0x51, 0x19, 0x48, 0x70,
+		0x21, 0xb4, 0xb8, 0x4e, 0x15, 0x65, 0xe3, 0xca, 0x31, 0x96, 0x7a, 0xc8,
+		0x60, 0x4d, 0x40, 0x32, 0x17, 0x0d, 0xec, 0x28, 0x0a, 0xee, 0xfa, 0x09,
+		0x5d, 0x08, 0xb3, 0xb7, 0x24, 0x1e, 0xf6, 0x64, 0x6a, 0x6c, 0x86, 0xe5,
+		0xc6, 0x2c, 0xe0, 0x8b, 0xe0, 0x99,
+	}
+	copy(clientHello, clientInitial)
+
+	s := quicStream{}
+	u, _ := s.Feed(true, clientHello)
+	if u == nil || u.M.Get("req") == nil {
+		t.Fatal("Feed(rev=true) did not parse ClientHello")
+	}
+}