Stabilize concurrent SSH and WebSocket transports

src/session_broker.c

@@ -11,6 +11,7 @@
 #include "serial_service.h"
 
 #define SESSION_BROKER_RX_CHUNK_SIZE 256U
+#define SESSION_BROKER_ACTIVE_BURST_BYTES (8U * SESSION_BROKER_RX_CHUNK_SIZE)
 #define SESSION_BROKER_TASK_STACK_SIZE 4096U
 #define SESSION_BROKER_TASK_PRIORITY 9U
 #define SESSION_BROKER_IDLE_POLL_MS 5U
@@ -160,6 +161,7 @@ static void broker_task(void *context)
 {
     (void)context;
     uint8_t data[SESSION_BROKER_RX_CHUNK_SIZE];
+    size_t active_burst_bytes = 0U;
 
     for (;;) {
         /*
@@ -175,7 +177,20 @@ static void broker_task(void *context)
         xSemaphoreGive(s_mutex);
 
         if (received == 0U) {
+            active_burst_bytes = 0U;
             vTaskDelay(milliseconds_to_ticks(SESSION_BROKER_IDLE_POLL_MS));
+        } else {
+            active_burst_bytes += received;
+            if (active_burst_bytes >= SESSION_BROKER_ACTIVE_BURST_BYTES) {
+                active_burst_bytes = 0U;
+                /*
+                 * A continuously readable UART must not make this priority-9
+                 * task permanently runnable. One tick after each bounded burst
+                 * preserves 1 Mbaud headroom while allowing idle and transports
+                 * to run on a loaded dual-core system.
+                 */
+                vTaskDelay(1U);
+            }
         }
     }
 }

src/ssh_transport.c

@@ -18,6 +18,7 @@
 #include "lwip/inet.h"
 #include "lwip/sockets.h"
 #include "lwip/tcp.h"
+#include "sdkconfig.h"
 #include "secure_random.h"
 #include "serial_service.h"
 #include "ssh_security.h"
@@ -26,6 +27,14 @@
 #include <wolfssl/wolfcrypt/random.h>
 #include <wolfssh/ssh.h>
 
+#if defined(CONFIG_MBEDTLS_HARDWARE_AES) && CONFIG_MBEDTLS_HARDWARE_AES
+#error "Concurrent mbedTLS/wolfSSH operation requires mbedTLS software AES"
+#endif
+#if !defined(NO_WOLFSSL_ESP32_CRYPT_AES) || \
+    !defined(NO_WOLFSSL_ESP32_CRYPT_HASH)
+#error "wolfSSH AES/SHA must not use independently locked ESP32 crypto hardware"
+#endif
+
 #define SSH_TRANSPORT_TASK_STACK_SIZE 20480U
 #define SSH_TRANSPORT_TASK_PRIORITY 5U
 #define SSH_TRANSPORT_TASK_CORE 1

src/usb_cdc_transport.c

@@ -58,7 +58,7 @@ static bool s_line_coding_pending;
 static usb_cdc_transport_counters_t s_counters;
 
 static const char s_language_descriptor[] = {0x09, 0x04};
-static const char s_manufacturer[] = "ESP32 Serial Tools";
+static const char s_manufacturer[] = "Commander1024";
 /* esp_tinyusb's default UTF-16 conversion accepts at most 31 characters. */
 static const char s_product[] = "ESP32 Serial Swiss Army Knife";
 static char s_serial_number[13];

src/web_serial_transport.c

@@ -27,7 +27,8 @@
 #define WEB_SERIAL_ORIGIN_CAPACITY (sizeof("https://") + WEB_SERIAL_HOST_CAPACITY)
 #define WEB_SERIAL_TICKET_RESPONSE_CAPACITY 96U
 #define WEB_SERIAL_TASK_STACK_SIZE 6144U
-#define WEB_SERIAL_TASK_PRIORITY 7U
+#define WEB_SERIAL_TASK_PRIORITY 4U
+#define WEB_SERIAL_ACTIVE_BURST_LOOPS 8U
 #define WEB_SERIAL_POLL_MS 5U
 #define WEB_SERIAL_DETACH_TIMEOUT_US 1000000LL
 
@@ -1214,6 +1215,8 @@ static void process_active_output(web_serial_slot_t *slot)
 static void transport_task(void *context)
 {
     (void)context;
+    size_t active_burst_loops = 0U;
+
     for (;;) {
         for (size_t index = 0U; index < WEB_SERIAL_TRANSPORT_MAX_SESSIONS;
              ++index) {
@@ -1222,8 +1225,20 @@ static void transport_task(void *context)
             process_broker_disconnect(slot);
             process_active_output(slot);
         }
-        (void)ulTaskNotifyTake(pdTRUE,
-                              milliseconds_to_ticks(WEB_SERIAL_POLL_MS));
+
+        uint32_t notifications = ulTaskNotifyTake(
+            pdTRUE, milliseconds_to_ticks(WEB_SERIAL_POLL_MS));
+        if (notifications == 0U) {
+            active_burst_loops = 0U;
+        } else if (++active_burst_loops >= WEB_SERIAL_ACTIVE_BURST_LOOPS) {
+            active_burst_loops = 0U;
+            /*
+             * Send completion normally wakes this task immediately. Bound that
+             * producer/HTTPD hand-off so sustained serial output cannot keep an
+             * application task runnable forever and starve an idle watchdog.
+             */
+            vTaskDelay(1U);
+        }
     }
 }