Addresses PR #46 review comments:

main/main.c

@@ -68,6 +68,7 @@ static void resync_wrapper(tcp_bridge_resync_type_t type, const uint8_t *data, i
         case TCP_BRIDGE_RESYNC_BAD_END:             s_pool_state.resyncs_bad_end++;             break;
         case TCP_BRIDGE_RESYNC_BAD_DATA_CHECKSUM:   s_pool_state.resyncs_bad_data_checksum++;   break;
         case TCP_BRIDGE_RESYNC_BUFFER_OVERFLOW:     s_pool_state.resyncs_buffer_overflow++;     break;
+        default:                                    s_pool_state.resyncs_unexpected++;          break;
     }
     xSemaphoreGive(s_pool_state_mutex);
 

main/message_decoder.c

@@ -2899,6 +2899,11 @@ static bool handle_pump_buttons(
 
 static bool dispatch_message(const uint8_t *data, int len, const uint8_t *payload, int payload_len, const char *addr_info, message_decoder_context_t *ctx);
 
+// This function assumes the framing layer has validated that the message buffer
+// has valid checksums, start and stop bytes etc. It does not repeat the validation.
+// Note also that this function can be called directly by the test harness and from 
+// the TX-echo path - in these cases it is incumbent on the caller to ensure that
+// messages are valid.
 bool decode_message(const uint8_t *data, int len, message_decoder_context_t *ctx)
 {
     if (!ctx || !ctx->pool_state) {

main/pool_state.h

@@ -259,6 +259,7 @@ typedef struct {
     uint32_t resyncs_bad_end;             // End byte != 0x03 at declared length
     uint32_t resyncs_bad_data_checksum;   // Data checksum mismatch
     uint32_t resyncs_buffer_overflow;     // Buffer filled without a complete frame
+    uint32_t resyncs_unexpected;          // Resync for unexpected reason - this should be investigated
 
     // Timers (up to MAX_TIMERS)
     timer_state_t timers[MAX_TIMERS];

main/web_handlers.c

@@ -639,6 +639,7 @@ static esp_err_t status_get_handler(httpd_req_t *req)
     cJSON_AddNumberToObject(resyncs, "bad_end",         state.resyncs_bad_end);
     cJSON_AddNumberToObject(resyncs, "data_checksum",   state.resyncs_bad_data_checksum);
     cJSON_AddNumberToObject(resyncs, "buffer_overflow", state.resyncs_buffer_overflow);
+    cJSON_AddNumberToObject(resyncs, "unexpected",      state.resyncs_unexpected);
     cJSON_AddItemToObject(root, "resyncs", resyncs);
 
     // Devices observed on the bus