bbdr: rename BBR log fields, add mode transition logs, configurable max inflight

src/config_parser.c

@@ -720,7 +720,7 @@ static struct utun_config* parse_config_internal(FILE *fp, const char *filename)
     cfg->global.name[0] = '\0';
     cfg->global.keepalive_timeout = 2000;  // Default 2 seconds
     cfg->global.keepalive_interval = 200;   // Default 0.2 s
-    cfg->global.bbr_max_cwnd = 100000;  // Default 100KB
+    cfg->global.bbr_max_cwnd = 1048576; // Default 1MB (was INFLIGHT_LIM_MAX)
     cfg->global.firewall_rules = NULL;
     cfg->global.firewall_rule_count = 0;
     cfg->global.firewall_bypass_all = 0;

src/etcp.c

@@ -207,6 +207,7 @@ struct ETCP_CONN* etcp_connection_create(struct UTUN_INSTANCE* instance, char* n
     etcp->ack_q = queue_new(instance->ua, INFLIGHT_INITIAL_HASH_SIZE, 0, 4, "ack_q");
     etcp->inflight_pool = memory_pool_init(sizeof(struct INFLIGHT_PACKET), "inflight_pool");
     etcp->io_pool = memory_pool_init(sizeof(struct ETCP_FRAGMENT), "io_pool");
+    etcp->max_inflight = (uint32_t)instance->config->global.bbr_max_cwnd;
     etcp->optimal_inflight=100000;
     etcp->initialized=0;
     etcp->links_up=0;
@@ -1245,10 +1246,10 @@ void etcp_ack_recv(struct ETCP_CONN* etcp, uint32_t seq, uint16_t ts, uint16_t d
             link->delivered_bytes += rs.delivered;
             link->last_ack_time_tb = now_tb;
 
-            DEBUG_DEBUG(DEBUG_CATEGORY_BBR, "[L%u] BBR in: seq=%u del=%u iv=%uus rtt=%uus pri=%u infl=%u lost=%d app=%d cwnd=%u",
+            DEBUG_DEBUG(DEBUG_CATEGORY_BBR, "[L%u] BBR in: seq=%u del=%u iv=%uus rtt=%uus pri=%u tx_infl=%u cur=%u/%u lost=%d app=%d",
                 link->local_link_id, seq, rs.delivered, rs.interval_us, rs.rtt_us,
-                rs.prior_delivered, rs.tx_in_flight, rs.lost, rs.is_app_limited,
-                link->inflight_lim_bytes);
+                rs.prior_delivered, rs.tx_in_flight, link->inflight_bytes, link->inflight_lim_bytes,
+                rs.lost, rs.is_app_limited);
 
             uint32_t old_cwnd = link->inflight_lim_bytes;
             uint32_t old_pacing = link->bbr_pacing_rate;
@@ -1261,9 +1262,9 @@ void etcp_ack_recv(struct ETCP_CONN* etcp, uint32_t seq, uint16_t ts, uint16_t d
             link->bandwidth          = (uint32_t)((uint64_t)new_pacing * 8 / 1000);
             link->bbr_loss_since_ack = 0;
 
-            DEBUG_DEBUG(DEBUG_CATEGORY_BBR, "[L%u] BBR out: cwnd %u→%u pace %u→%u bw=%uK mode=%d cyc=%d infl=%u",
+            DEBUG_DEBUG(DEBUG_CATEGORY_BBR, "[L%u] BBR out: cwnd %u→%u pace %u→%u bw=%uK mode=%d cyc=%d infl=%u/%u",
                 link->local_link_id, old_cwnd, new_cwnd, old_pacing, new_pacing,
-                link->bandwidth, link->bbr->mode, link->bbr->cycle_idx, link->inflight_bytes);
+                link->bandwidth, link->bbr->mode, link->bbr->cycle_idx, link->inflight_bytes, new_cwnd);
 
             link->acked_bytes   += acked_pkt->ll.len;
             link->acked_packets++;

src/etcp.h

@@ -154,7 +154,7 @@ struct ETCP_CONN {
 
     // Window and inflight management
     uint32_t unacked_bytes;        // Current inflight bytes
-    // uint32_t window_size;          // Receive window - Not used
+    uint32_t max_inflight;         // Max inflight cap from config (bbr_max_cwnd)
     uint32_t optimal_inflight;     // Sum over links
 
     // Timers

src/etcp_bbr.c

@@ -1,5 +1,6 @@
 #include "etcp_bbr.h"
 #include "../lib/u_async.h"
+#include "../lib/debug_config.h"
 #include <stdlib.h>
 
 static uint64_t bbr_now(const struct bbr* bbr) { return bbr->now_tb ? bbr->now_tb : get_time_tb(); }
@@ -327,10 +328,14 @@ static void bbr_exit_probe_rtt(struct bbr* bbr)
 {
     bbr_reset_lower_bounds(bbr);
     if (bbr->full_bw_reached) {
+        DEBUG_DEBUG(DEBUG_CATEGORY_BBR, "[L%u] mode %d→%d exit probe_rtt → PROBE_BW",
+            bbr->link_id, bbr->mode, BBR_PROBE_BW);
         bbr->mode = BBR_PROBE_BW;
         bbr_start_bw_probe_down(bbr);
         bbr_start_bw_probe_cruise(bbr);
     } else {
+        DEBUG_DEBUG(DEBUG_CATEGORY_BBR, "[L%u] mode %d→%d exit probe_rtt → STARTUP",
+            bbr->link_id, bbr->mode, BBR_STARTUP);
         bbr->mode = BBR_STARTUP;
     }
 }
@@ -536,11 +541,13 @@ static void bbr_check_drain(struct bbr* bbr, const struct bbr_rate_sample* rs,
 {
     (void)rs; (void)sample_bw;
     if (bbr->mode == BBR_STARTUP && bbr->full_bw_reached) {
+        DEBUG_DEBUG(DEBUG_CATEGORY_BBR, "[L%u] mode %d→%d STARTUP→DRAIN", bbr->link_id, bbr->mode, BBR_DRAIN);
         bbr->mode = BBR_DRAIN;
         bbr_reset_congestion_signals(bbr);
     }
     if (bbr->mode == BBR_DRAIN &&
         inflight_packets <= bbr_inflight(bbr, bbr_max_bw(bbr), BBR_UNIT, mss)) {
+        DEBUG_DEBUG(DEBUG_CATEGORY_BBR, "[L%u] mode %d→%d DRAIN→PROBE_BW infl_pkt=%u", bbr->link_id, bbr->mode, BBR_PROBE_BW, inflight_packets);
         bbr->mode = BBR_PROBE_BW;
         bbr_start_bw_probe_down(bbr);
     }
@@ -584,6 +591,8 @@ static void bbr_update_min_rtt(struct bbr* bbr, const struct bbr_rate_sample* rs
 
     if (BBR_PROBE_RTT_MS > 0 && probe_rtt_expired &&
         !bbr->idle_restart && bbr->mode != BBR_PROBE_RTT) {
+        DEBUG_DEBUG(DEBUG_CATEGORY_BBR, "[L%u] mode %d→%d →PROBE_RTT cwnd=%u infl_pkt=%u",
+            bbr->link_id, bbr->mode, BBR_PROBE_RTT, *cwnd, inflight_packets);
         bbr->mode = BBR_PROBE_RTT;
         bbr_save_cwnd(bbr, *cwnd);
         bbr->probe_rtt_done_stamp_tb = 0;
@@ -610,6 +619,7 @@ static void bbr_update_min_rtt(struct bbr* bbr, const struct bbr_rate_sample* rs
 
 static void bbr_reset_startup_mode(struct bbr* bbr)
 {
+    DEBUG_DEBUG(DEBUG_CATEGORY_BBR, "[L%u] mode %d→%d →STARTUP (reset)", bbr->link_id, bbr->mode, BBR_STARTUP);
     bbr->mode = BBR_STARTUP;
 }
 

src/etcp_bbr.h

@@ -98,6 +98,7 @@ struct bbr {
     uint8_t  loss_round_start : 1;
     uint8_t  full_bw_now      : 1;
     uint8_t  pad_unused       : 6;
+    uint8_t  link_id;              // local_link_id for debug logging
     uint64_t now_tb;               // 0 = real get_time_tb(); >0 = test-controlled time
     bbr_cwnd_update_fn on_cwnd_update;
     void* cwnd_update_ctx;

src/etcp_connections.c

@@ -815,6 +815,7 @@ struct ETCP_LINK* etcp_link_new(struct ETCP_CONN* etcp, struct ETCP_SOCKET* conn
         return NULL;
     }
     link->local_link_id = (uint8_t)free_id;
+    if (link->bbr) link->bbr->link_id = (uint8_t)free_id;
 
     memcpy(&link->remote_addr, remote_addr, sizeof(struct sockaddr_storage));
 
@@ -849,7 +850,7 @@ struct ETCP_LINK* etcp_link_new(struct ETCP_CONN* etcp, struct ETCP_SOCKET* conn
 void etcp_link_update_inflight_lim(struct ETCP_LINK* link, uint32_t new_lim) {
     if (!link || !link->etcp) return;
     if (new_lim < INFLIGHT_LIM_MIN) new_lim = INFLIGHT_LIM_MIN;
-    if (new_lim > INFLIGHT_LIM_MAX) new_lim = INFLIGHT_LIM_MAX;
+    if (new_lim > link->etcp->max_inflight) new_lim = link->etcp->max_inflight;
 
     uint32_t old = link->inflight_lim_bytes;
     link->inflight_lim_bytes = new_lim;