From 229e992695cc214e1c788f51f571d24798e8ae14 Mon Sep 17 00:00:00 2001
From: evgeny <evgeny@adaptto.ru>
Date: Fri, 23 Oct 2026 00:16:40 +0200
Subject: [PATCH] Cover probing byte budgets and ACK aggregation beyond 64KiB

---
 tests/test_etcp_bbr.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/tests/test_etcp_bbr.c b/tests/test_etcp_bbr.c
index e7d66beb..fe46902e 100644
--- a/tests/test_etcp_bbr.c
+++ b/tests/test_etcp_bbr.c
@@ -94,6 +94,39 @@ static int test_probe_growth_bytes(void) {
     PASS(); return 0;
 }
 
+static int test_probe_packet_budget(void) {
+    MSEG("PROBE_UP reserves two MSS; Reno rounds use packets");
+    struct bbr s = { .now_tb = 10000 }; bbr_init(&s);
+    s.mode = BBR_PROBE_BW; s.full_bw_reached = 1; s.cycle_idx = BBR_BW_PROBE_UP;
+    uint32_t cwnd = 100000, pacing = 0;
+    struct bbr_rate_sample rs = { .delivered = 10000, .interval_us = 10000, .rtt_us = 20000,
+        .acked_sacked = 1000, .tx_in_flight = 40000 };
+    bbr_main(&s, &rs, &cwnd, &pacing, 1400, 40000, 0);
+    if (cwnd != 43800) FAIL("two MSS probing reserve must add 2800 bytes to 41000");
+    memset(&s, 0, sizeof(s)); s.now_tb = 10000; bbr_init(&s);
+    s.mode = BBR_PROBE_BW; s.full_bw_reached = 1; s.cycle_idx = BBR_BW_PROBE_CRUISE;
+    s.min_rtt_us = s.probe_rtt_min_us = 14000; s.has_seen_rtt = 1;
+    s.bw_hi[0] = BW_UNIT; s.rounds_since_probe = 9; s.cycle_mstamp_tb = s.now_tb; s.probe_wait_us = 2000000;
+    cwnd = 56000; pacing = 0; rs.rtt_us = 14000;
+    bbr_main(&s, &rs, &cwnd, &pacing, 1400, 14000, 0);
+    if (s.cycle_idx != BBR_BW_PROBE_REFILL) FAIL("ten-packet BDP should probe after ten packet rounds");
+    PASS(); return 0;
+}
+
+static int test_large_ack_aggregation(void) {
+    MSEG("ACK aggregation above 64KiB keeps byte precision");
+    struct bbr s = { .now_tb = 10000 }; bbr_init(&s);
+    s.mode = BBR_PROBE_BW; s.full_bw_reached = 1; s.cycle_idx = BBR_BW_PROBE_CRUISE;
+    s.cycle_mstamp_tb = s.now_tb; s.probe_wait_us = 2000000;
+    uint32_t cwnd = 300000, pacing = 0;
+    struct bbr_rate_sample rs = { .delivered = 80000, .interval_us = 80000, .rtt_us = 100000,
+        .acked_sacked = 80000, .tx_in_flight = 200000 };
+    bbr_main(&s, &rs, &cwnd, &pacing, 1400, 200000, 0);
+    DEBUG_INFO(DEBUG_CATEGORY_DEBUG, "ACK aggregation: 2*BDP=200000 ACKed=80000 cwnd=%u", cwnd);
+    if (cwnd != 280000) FAIL("80000-byte ACK aggregation must not wrap at 65536");
+    PASS(); return 0;
+}
+
 static int test_init(void)
 {
     MSEG("bbr_init — startup mode");
@@ -211,6 +244,8 @@ int main(void)
     test_byte_rate();
     test_large_rate();
     test_probe_growth_bytes();
+    test_probe_packet_budget();
+    test_large_ack_aggregation();
     test_init();
     test_startup_growth();
     test_full_bw();