From 3239eaf9c8160933ee07a7ffe933cb4dadae8f77 Mon Sep 17 00:00:00 2001
From: jess <jess@else-if.org>
Date: Fri, 3 Apr 2026 03:48:42 -0700
Subject: [PATCH] implement UDP zombie reaper task

---
 main/wifi_transport.c | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/main/wifi_transport.c b/main/wifi_transport.c
index 47c9d04..7a9df04 100644
--- a/main/wifi_transport.c
+++ b/main/wifi_transport.c
@@ -20,6 +20,9 @@
 #define UDP_PORT           5941
 #define UDP_BUF_SIZE       128
 #define UDP_CLIENTS_MAX    16
+#define REAP_THRESHOLD     10
+#define REAP_WINDOW_MS     200
+#define REAP_INTERVAL_MS   5000
 
 static int udp_sock = -1;
 static esp_netif_t *ap_netif;
@@ -236,6 +239,39 @@ static void udp_rx_task(void *param)
     }
 }
 
+static void udp_reaper_task(void *arg)
+{
+    (void)arg;
+    for (;;) {
+        vTaskDelay(pdMS_TO_TICKS(REAP_INTERVAL_MS));
+
+        xSemaphoreTake(client_mutex, portMAX_DELAY);
+        if (client_count < REAP_THRESHOLD) {
+            xSemaphoreGive(client_mutex);
+            continue;
+        }
+
+        uint32_t cutoff = xTaskGetTickCount() * portTICK_PERIOD_MS;
+        printf("REAP: cycle start, %d clients\n", client_count);
+        xSemaphoreGive(client_mutex);
+
+        send_keepalive();
+        vTaskDelay(pdMS_TO_TICKS(REAP_WINDOW_MS));
+
+        xSemaphoreTake(client_mutex, portMAX_DELAY);
+        int reaped = 0;
+        for (int i = client_count - 1; i >= 0; i--) {
+            if (clients[i].last_touch_ms < cutoff) {
+                client_remove_by_index(i);
+                reaped++;
+            }
+        }
+        xSemaphoreGive(client_mutex);
+
+        if (reaped) printf("REAP: removed %d zombie(s), %d remain\n", reaped, client_count);
+    }
+}
+
 int wifi_send_sysex(const uint8_t *sysex, uint16_t len)
 {
     if (udp_sock < 0 || client_count == 0)
@@ -384,5 +420,6 @@ int wifi_transport_init(void)
     }
 
     xTaskCreate(udp_rx_task, "udp_rx", 4096, NULL, 5, NULL);
+    xTaskCreate(udp_reaper_task, "reaper", 2048, NULL, 4, NULL);
     return 0;
 }