fix(qos): harmonize SQM and CAKE cooperation, resolve bufferbloat degradation

tachyon/files/usr/lib/diagnostics/runtime.uc

@@ -2774,6 +2774,67 @@ function run_doctor_checks_impl(repair) {
         }
     }
 
+    // 4b3. SQM (Smart Queue Management) & Bufferbloat compatibility
+    let sqm_queues = uci_core.section_objects("sqm", "queue");
+    let sqm_enabled_count = 0;
+    let sqm_lan_bridge_conflict = null;
+    let lan_bridge_ports = [];
+    let br_lan_ports = uci_core.get("network.br_lan.ports") || uci_core.get("network.lan.ports") || [];
+    if (type(br_lan_ports) == "string") br_lan_ports = split(br_lan_ports, /\s+/);
+    if (type(br_lan_ports) == "array") {
+        for (let p in br_lan_ports) push(lan_bridge_ports, as_string(p));
+    }
+    push(lan_bridge_ports, "br-lan");
+
+    if (sqm_queues && length(sqm_queues) > 0) {
+        for (let q in sqm_queues) {
+            if (q && (q.enabled == "1" || q.enabled == true)) {
+                sqm_enabled_count++;
+                let q_iface = as_string(q.interface || "");
+                for (let bp in lan_bridge_ports) {
+                    if (q_iface == bp && bp != "") {
+                        sqm_lan_bridge_conflict = q_iface;
+                        break;
+                    }
+                }
+            }
+        }
+    }
+
+    if (sqm_enabled_count > 0) {
+        let flow_offload = uci_core.get("firewall.@defaults[0].flow_offloading");
+        if (flow_offload == "1" || flow_offload == "true") {
+            issues++;
+            if (!DOCTOR_REPAIR_MODE) {
+                doc_plan("uci set firewall.@defaults[0].flow_offloading='0' + firewall reload");
+                doc_check("⚠️", "SQM / Flow Offloading", "conflict (flow offload bypasses SQM queues)",
+                    "→ WILL FIX (doctor --fix): отключение flow_offloading для устранения bufferbloat");
+            } else {
+                doc_set("firewall.@defaults[0].flow_offloading", "0");
+                doc_commit("firewall");
+                command_status("/etc/init.d/firewall reload >/dev/null 2>&1");
+                command_status("sleep 1");
+                let fo2 = uci_core.get("firewall.@defaults[0].flow_offloading");
+                if (fo2 != "1" && fo2 != "true") {
+                    doc_check("❌", "SQM / Flow Offloading", "conflict", "→ FIXED: flow_offloading=0 (SQM bufferbloat восстановлен)");
+                    fixed++;
+                } else {
+                    doc_check("❌", "SQM / Flow Offloading", "conflict", "→ не удалось отключить flow_offloading");
+                }
+            }
+        } else {
+            doc_check("✅", "SQM / Flow Offloading", "compatible (flow_offloading=0)", "");
+        }
+
+        if (sqm_lan_bridge_conflict != null) {
+            issues++;
+            doc_check("⚠️", "SQM interface (" + sqm_lan_bridge_conflict + ")", "misconfigured on LAN bridge",
+                "→ Привяжите очередь SQM к WAN интерфейсу (pppoe-wan/wan)");
+        } else {
+            doc_check("✅", "SQM (CAKE/fq_codel)", "active (QoS cooperative mode)", "");
+        }
+    }
+
     // 4c. Resolv.conf symlink
     let resolv_link = "";
     // Throws when /etc/resolv.conf is a regular file rather than a symlink,

tachyon/files/usr/lib/nft/apply.uc

@@ -1700,7 +1700,8 @@ function nft_create_runtime_base(table, localv4_set, common_set, port_set, ip_po
 
     // QoS Low-Latency Gaming & Voice Acceleration Engine
     let qos_setting = uci_settings().qos_priority_engine;
-    let qos_enabled = (qos_setting == "1" || (qos_setting != "0" && !sqm_service_enabled()));
+    let sqm_active = sqm_service_enabled();
+    let qos_enabled = (qos_setting == "1" || qos_setting != "0");
 
     if (qos_enabled) {
         // Voice & Discord RTC (DSCP EF 0x2e)
@@ -1711,8 +1712,12 @@ function nft_create_runtime_base(table, localv4_set, common_set, port_set, ip_po
         nft_add_rule(table, "mangle_forward", [ "udp", "dport", "{ 3074, 7000-9000, 27000-27050, 28960 }", "ip", "dscp", "set", "0x22" ]);
         nft_add_rule(table, "mangle_output", [ "udp", "dport", "{ 3074, 7000-9000, 27000-27050, 28960 }", "ip", "dscp", "set", "0x22" ]);
 
-        // Pure TCP ACK Acceleration (DSCP CS2) - only small packets without payload
-        nft_add_rule(table, "mangle_forward", [ "tcp", "flags", "&", "(fin|syn|rst|ack)", "==", "ack", "meta", "length", "<=", "64", "ip", "dscp", "set", "cs2" ]);
+        // Pure TCP ACK Acceleration (DSCP CS2) - only small packets without payload.
+        // When SQM (CAKE) is active, CAKE's built-in ack-filter handles ACKs natively,
+        // and setting CS2 on ACKs pollutes CAKE's Video tin (Tin 2) in diffserv4.
+        if (!sqm_active) {
+            nft_add_rule(table, "mangle_forward", [ "tcp", "flags", "&", "(fin|syn|rst|ack)", "==", "ack", "meta", "length", "<=", "64", "ip", "dscp", "set", "cs2" ]);
+        }
     }
 
     return true;

tachyon/files/usr/lib/service/event_controller.uc

@@ -722,19 +722,6 @@ function controller(bus, opts) {
 
         let qos_pref = setting("qos_priority_engine", "");
         if (qos_pref == "0") return;
-        if (qos_pref != "1") {
-            let queues = uci_core.section_objects("sqm", "queue");
-            let sqm_on = false;
-            if (queues && length(queues) > 0) {
-                for (let q in queues) {
-                    if (q.enabled == "1" || q.enabled == true) {
-                        sqm_on = true;
-                        break;
-                    }
-                }
-            }
-            if (sqm_on) return;
-        }
         if ((index(out_nft, "dscp set 0x2e") < 0 && index(out_nft, "dscp set ef") < 0) ||
             (index(out_nft, "dscp set 0x22") < 0 && index(out_nft, "dscp set af41") < 0))
             bus.emit(EV.QOS_MISSING, { table: nft_table });