From a79c724110af48ae43ca079101629c7785adb0c0 Mon Sep 17 00:00:00 2001
From: evgeny <evgeny@adaptto.ru>
Date: Fri, 23 Oct 2026 00:15:46 +0200
Subject: [PATCH] Grow BBR probe inflight bounds in MSS-sized byte increments

---
 src/transport_layer/etcp_bbr.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/transport_layer/etcp_bbr.c b/src/transport_layer/etcp_bbr.c
index f6908d82..5b486b4f 100644
--- a/src/transport_layer/etcp_bbr.c
+++ b/src/transport_layer/etcp_bbr.c
@@ -280,13 +280,13 @@ static void bbr_check_full_bw_reached(struct bbr* bbr, const struct bbr_rate_sam
     bbr->full_bw_reached |= bbr->full_bw_now;
 }
 
-static void bbr_raise_inflight_hi_slope(struct bbr* bbr, uint32_t cwnd)
+static void bbr_raise_inflight_hi_slope(struct bbr* bbr, uint32_t cwnd, uint32_t mss)
 {
     uint32_t growth_this_round = 1U << bbr->bw_probe_up_rounds;
     uint32_t cnt;
     bbr->bw_probe_up_rounds = (uint8_t)(bbr->bw_probe_up_rounds + 1 < 30 ?
                                         bbr->bw_probe_up_rounds + 1 : 30);
-    cnt = cwnd / growth_this_round;
+    cnt = (uint32_t)((uint64_t)cwnd / ((uint64_t)growth_this_round * mss));
     cnt = (uint32_t)(cnt > 1U ? cnt : 1U);
     bbr->bw_probe_up_cnt = cnt;
 }
@@ -308,7 +308,7 @@ static void bbr_start_bw_probe_refill(struct bbr* bbr, uint32_t bw_probe_up_roun
     bbr_set_cycle_idx(bbr, BBR_BW_PROBE_REFILL);
 }
 
-static void bbr_start_bw_probe_up(struct bbr* bbr, uint32_t sample_bw, uint32_t cwnd)
+static void bbr_start_bw_probe_up(struct bbr* bbr, uint32_t sample_bw, uint32_t cwnd, uint32_t mss)
 {
     bbr->ack_phase = BBR_ACKS_PROBE_STARTING;
     bbr->next_rtt_delivered = bbr->delivered;
@@ -316,7 +316,7 @@ static void bbr_start_bw_probe_up(struct bbr* bbr, uint32_t sample_bw, uint32_t
     bbr_reset_full_bw(bbr);
     bbr->full_bw = sample_bw;
     bbr_set_cycle_idx(bbr, BBR_BW_PROBE_UP);
-    bbr_raise_inflight_hi_slope(bbr, cwnd);
+    bbr_raise_inflight_hi_slope(bbr, cwnd, mss);
 }
 
 static void bbr_save_cwnd(struct bbr* bbr, uint32_t cwnd)
@@ -402,7 +402,7 @@ static void bbr_handle_inflight_too_high(struct bbr* bbr, const struct bbr_rate_
 }
 
 static void bbr_probe_inflight_hi_upward(struct bbr* bbr, const struct bbr_rate_sample* rs,
-                                          int is_cwnd_limited, uint32_t cwnd)
+                                          int is_cwnd_limited, uint32_t cwnd, uint32_t mss)
 {
     uint32_t delta;
     if (!is_cwnd_limited || cwnd < bbr->inflight_hi)
@@ -416,7 +416,7 @@ static void bbr_probe_inflight_hi_upward(struct bbr* bbr, const struct bbr_rate_
         bbr->try_fast_path = 0;
     }
     if (bbr->round_start)
-        bbr_raise_inflight_hi_slope(bbr, cwnd);
+        bbr_raise_inflight_hi_slope(bbr, cwnd, mss);
 }
 
 static void bbr_adapt_upper_bounds(struct bbr* bbr, const struct bbr_rate_sample* rs,
@@ -447,7 +447,7 @@ static void bbr_adapt_upper_bounds(struct bbr* bbr, const struct bbr_rate_sample
         if (rs->tx_in_flight > bbr->inflight_hi)
             bbr->inflight_hi = rs->tx_in_flight;
         if (bbr->mode == BBR_PROBE_BW && bbr->cycle_idx == BBR_BW_PROBE_UP)
-            bbr_probe_inflight_hi_upward(bbr, rs, is_cwnd_limited, cwnd);
+            bbr_probe_inflight_hi_upward(bbr, rs, is_cwnd_limited, cwnd, mss);
     }
 }
 
@@ -507,7 +507,7 @@ static void bbr_update_cycle_phase(struct bbr* bbr, const struct bbr_rate_sample
     case BBR_BW_PROBE_REFILL:
         if (bbr->round_start) {
             bbr->bw_probe_samples = 1;
-            bbr_start_bw_probe_up(bbr, sample_bw, cwnd);
+            bbr_start_bw_probe_up(bbr, sample_bw, cwnd, mss);
         }
         break;
     case BBR_BW_PROBE_UP: