From 86db42524e5ec42ef2639ee22e4f080011e98afd Mon Sep 17 00:00:00 2001
From: Felipe Astroza <fastroza@cloudflare.com>
Date: Tue, 9 Sep 2025 12:29:01 -0500
Subject: [PATCH] BuildReport() was exceeding the maxSize limit

---
 pkg/rfc8888/recorder.go      | 12 ++--------
 pkg/rfc8888/recorder_test.go | 45 +++++++++++++++++++++++++++++-------
 2 files changed, 39 insertions(+), 18 deletions(-)

diff --git a/pkg/rfc8888/recorder.go b/pkg/rfc8888/recorder.go
index a1a2cf26..c5e81d46 100644
--- a/pkg/rfc8888/recorder.go
+++ b/pkg/rfc8888/recorder.go
@@ -49,17 +49,9 @@ func (r *Recorder) BuildReport(now time.Time, maxSize int) *rtcp.CCFeedbackRepor
 	}
 
 	maxReportBlocks := (maxSize - 12 - (8 * len(r.streams))) / 2
-	var maxReportBlocksPerStream int
-	if len(r.streams) > 1 {
-		maxReportBlocksPerStream = maxReportBlocks / (len(r.streams) - 1)
-	} else {
-		maxReportBlocksPerStream = maxReportBlocks
-	}
+	maxReportBlocksPerStream := maxReportBlocks / len(r.streams)
 
-	for i, log := range r.streams {
-		if len(r.streams) > 1 && int(i) == len(r.streams)-1 {
-			maxReportBlocksPerStream = maxReportBlocks % len(r.streams)
-		}
+	for _, log := range r.streams {
 		block := log.metricsAfter(now, int64(maxReportBlocksPerStream))
 		report.ReportBlocks = append(report.ReportBlocks, block)
 	}
diff --git a/pkg/rfc8888/recorder_test.go b/pkg/rfc8888/recorder_test.go
index e032a78f..3f8714b2 100644
--- a/pkg/rfc8888/recorder_test.go
+++ b/pkg/rfc8888/recorder_test.go
@@ -4,6 +4,7 @@
 package rfc8888
 
 import (
+	"math/rand"
 	"testing"
 	"time"
 
@@ -142,21 +143,49 @@ func TestRecorder(t *testing.T) {
 		}, report.ReportBlocks[0])
 	})
 
-	t.Run("MaxreportsPerStream", func(t *testing.T) {
+	t.Run("MaxreportsPerStream 3 streams", func(t *testing.T) {
 		recorder := NewRecorder()
 		now := time.Time{}
+		maxSize := 1200
 
+		streams := 3
+		packets := 1000
+		// Add 1000 packets on 3 different streams
+		for i := 0; i < streams; i++ {
+			ssrc := rand.Uint32() //nolint:gosec
+			for j := 0; j < packets; j++ {
+				recorder.AddPacket(now, ssrc, uint16(j), 0) //nolint:gosec // G115
+			}
+		}
+		reports := recorder.BuildReport(time.Time{}, maxSize)
+
+		blocks := 0
+		for i := 0; i < streams; i++ {
+			blocks += len(reports.ReportBlocks[i].MetricBlocks)
+		}
+		assert.Less(t, blocks*2, maxSize)
+	})
+
+	t.Run("MaxreportsPerStream 10 streams", func(t *testing.T) {
+		recorder := NewRecorder()
+		now := time.Time{}
+		maxSize := 1300
+
+		streams := 10
+		packets := 1000
 		// Add 1000 packets on 10 different streams
-		for i := 0; i < 10; i++ {
-			for j := 0; j < 100; j++ {
-				recorder.AddPacket(now, uint32(i), uint16(j), 0) //nolint:gosec // G115
+		for i := 0; i < streams; i++ {
+			ssrc := rand.Uint32() //nolint:gosec
+			for j := 0; j < packets; j++ {
+				recorder.AddPacket(now, ssrc, uint16(j), 0) //nolint:gosec // G115
 			}
 		}
-		reports := recorder.BuildReport(time.Time{}, 1380)
+		reports := recorder.BuildReport(time.Time{}, maxSize)
 
-		for i := 0; i < 10; i++ {
-			assert.Greater(t, 72, len(reports.ReportBlocks[i].MetricBlocks))
-			assert.Less(t, 3, len(reports.ReportBlocks[i].MetricBlocks))
+		blocks := 0
+		for i := 0; i < streams; i++ {
+			blocks += len(reports.ReportBlocks[i].MetricBlocks)
 		}
+		assert.Less(t, blocks*2, maxSize)
 	})
 }