From ed263b07270096ebf8062d155052c3a9d727beb3 Mon Sep 17 00:00:00 2001 From: liamcottle Date: Sat, 3 Jan 2026 15:39:57 +1300 Subject: [PATCH 1/3] implement frame header parising for wifi interface --- src/helpers/esp32/SerialWifiInterface.cpp | 85 +++++++++++++++++++++-- src/helpers/esp32/SerialWifiInterface.h | 7 ++ 2 files changed, 86 insertions(+), 6 deletions(-) diff --git a/src/helpers/esp32/SerialWifiInterface.cpp b/src/helpers/esp32/SerialWifiInterface.cpp index 2df9980a..9470c827 100644 --- a/src/helpers/esp32/SerialWifiInterface.cpp +++ b/src/helpers/esp32/SerialWifiInterface.cpp @@ -54,6 +54,9 @@ size_t SerialWifiInterface::checkRecvFrame(uint8_t dest[]) { // switch active connection to new client client = newClient; + + // forget received frame header + received_frame_header = NULL; } @@ -86,13 +89,83 @@ size_t SerialWifiInterface::checkRecvFrame(uint8_t dest[]) { send_queue[i] = send_queue[i + 1]; } } else { - int len = client.available(); - if (len > 0) { - uint8_t buf[MAX_FRAME_SIZE + 4]; - client.readBytes(buf, len); - memcpy(dest, buf+3, len-3); // remove header (don't even check ... problems are on the other dir) - return len-3; + + // check if we are waiting for a frame header + if(received_frame_header == NULL){ + + // make sure we have received enough bytes for a frame header + // 3 bytes frame header = (1 byte frame type) + (2 bytes frame length as unsigned 16-bit little endian) + int frame_header_length = 3; + if(client.available() >= frame_header_length){ + + // read frame header + uint8_t frame_header[3]; + client.readBytes(frame_header, frame_header_length); + + // parse frame header + uint8_t frame_type = frame_header[0]; + uint16_t frame_length; + memcpy(&frame_length, &frame_header[1], 2); + + // we have received a frame header + received_frame_header = new FrameHeader(); + received_frame_header->type = frame_type; + received_frame_header->length = frame_length; + + } + } + + // check if we have received a frame header + if(received_frame_header){ + + // make sure we have received enough bytes for the required frame length + int available = client.available(); + int frame_type = received_frame_header->type; + int frame_length = received_frame_header->length; + if(frame_length > available){ + WIFI_DEBUG_PRINTLN("Waiting for %d more bytes", frame_length - available); + return 0; + } + + // skip frames that are larger than MAX_FRAME_SIZE + if(frame_length > MAX_FRAME_SIZE){ + WIFI_DEBUG_PRINTLN("Skipping frame: length=%d is larger than MAX_FRAME_SIZE=%d", frame_length, MAX_FRAME_SIZE); + while(frame_length > 0){ + uint8_t skip[1]; + int skipped = client.read(skip, 1); + frame_length -= skipped; + } + received_frame_header = NULL; + return 0; + } + + // skip frames that are not expected type + // '<' is 0x3c which indicates a frame sent from app to radio + if(frame_type != '<'){ + WIFI_DEBUG_PRINTLN("Skipping frame: type=0x%x is unexpected", frame_type); + while(frame_length > 0){ + uint8_t skip[1]; + int skipped = client.read(skip, 1); + frame_length -= skipped; + } + received_frame_header = NULL; + return 0; + } + + // read frame data + uint8_t frame_data[MAX_FRAME_SIZE]; + client.readBytes(frame_data, frame_length); + + // copy frame to provided buffer + memcpy(dest, frame_data, frame_length); + + // ready for next frame + received_frame_header = NULL; + return frame_length; + + } + } } diff --git a/src/helpers/esp32/SerialWifiInterface.h b/src/helpers/esp32/SerialWifiInterface.h index 2b6c6edd..c7139b40 100644 --- a/src/helpers/esp32/SerialWifiInterface.h +++ b/src/helpers/esp32/SerialWifiInterface.h @@ -12,11 +12,18 @@ class SerialWifiInterface : public BaseSerialInterface { WiFiServer server; WiFiClient client; + struct FrameHeader { + uint8_t type; + uint16_t length; + }; + struct Frame { uint8_t len; uint8_t buf[MAX_FRAME_SIZE]; }; + FrameHeader* received_frame_header = NULL; + #define FRAME_QUEUE_SIZE 4 int recv_queue_len; Frame recv_queue[FRAME_QUEUE_SIZE]; From 71bb49e556d11e2fb4276c4346d901f125ff1850 Mon Sep 17 00:00:00 2001 From: liamcottle Date: Sat, 3 Jan 2026 16:36:19 +1300 Subject: [PATCH 2/3] remove use of dynamic allocation --- src/helpers/esp32/SerialWifiInterface.cpp | 30 ++++++++++++++--------- src/helpers/esp32/SerialWifiInterface.h | 7 +++++- 2 files changed, 25 insertions(+), 12 deletions(-) diff --git a/src/helpers/esp32/SerialWifiInterface.cpp b/src/helpers/esp32/SerialWifiInterface.cpp index 9470c827..de5cce78 100644 --- a/src/helpers/esp32/SerialWifiInterface.cpp +++ b/src/helpers/esp32/SerialWifiInterface.cpp @@ -43,6 +43,15 @@ bool SerialWifiInterface::isWriteBusy() const { return false; } +bool SerialWifiInterface::hasReceivedFrameHeader() { + return received_frame_header.type != 0 && received_frame_header.length != 0; +} + +void SerialWifiInterface::resetReceivedFrameHeader() { + received_frame_header.type = 0; + received_frame_header.length = 0; +} + size_t SerialWifiInterface::checkRecvFrame(uint8_t dest[]) { // check if new client connected auto newClient = server.available(); @@ -56,7 +65,7 @@ size_t SerialWifiInterface::checkRecvFrame(uint8_t dest[]) { client = newClient; // forget received frame header - received_frame_header = NULL; + resetReceivedFrameHeader(); } @@ -91,7 +100,7 @@ size_t SerialWifiInterface::checkRecvFrame(uint8_t dest[]) { } else { // check if we are waiting for a frame header - if(received_frame_header == NULL){ + if(!hasReceivedFrameHeader()){ // make sure we have received enough bytes for a frame header // 3 bytes frame header = (1 byte frame type) + (2 bytes frame length as unsigned 16-bit little endian) @@ -108,21 +117,20 @@ size_t SerialWifiInterface::checkRecvFrame(uint8_t dest[]) { memcpy(&frame_length, &frame_header[1], 2); // we have received a frame header - received_frame_header = new FrameHeader(); - received_frame_header->type = frame_type; - received_frame_header->length = frame_length; + received_frame_header.type = frame_type; + received_frame_header.length = frame_length; } } // check if we have received a frame header - if(received_frame_header){ + if(hasReceivedFrameHeader()){ // make sure we have received enough bytes for the required frame length int available = client.available(); - int frame_type = received_frame_header->type; - int frame_length = received_frame_header->length; + int frame_type = received_frame_header.type; + int frame_length = received_frame_header.length; if(frame_length > available){ WIFI_DEBUG_PRINTLN("Waiting for %d more bytes", frame_length - available); return 0; @@ -136,7 +144,7 @@ size_t SerialWifiInterface::checkRecvFrame(uint8_t dest[]) { int skipped = client.read(skip, 1); frame_length -= skipped; } - received_frame_header = NULL; + resetReceivedFrameHeader(); return 0; } @@ -149,7 +157,7 @@ size_t SerialWifiInterface::checkRecvFrame(uint8_t dest[]) { int skipped = client.read(skip, 1); frame_length -= skipped; } - received_frame_header = NULL; + resetReceivedFrameHeader(); return 0; } @@ -161,7 +169,7 @@ size_t SerialWifiInterface::checkRecvFrame(uint8_t dest[]) { memcpy(dest, frame_data, frame_length); // ready for next frame - received_frame_header = NULL; + resetReceivedFrameHeader(); return frame_length; } diff --git a/src/helpers/esp32/SerialWifiInterface.h b/src/helpers/esp32/SerialWifiInterface.h index c7139b40..19291497 100644 --- a/src/helpers/esp32/SerialWifiInterface.h +++ b/src/helpers/esp32/SerialWifiInterface.h @@ -22,7 +22,7 @@ class SerialWifiInterface : public BaseSerialInterface { uint8_t buf[MAX_FRAME_SIZE]; }; - FrameHeader* received_frame_header = NULL; + FrameHeader received_frame_header; #define FRAME_QUEUE_SIZE 4 int recv_queue_len; @@ -40,6 +40,8 @@ public: _isEnabled = false; _last_write = 0; send_queue_len = recv_queue_len = 0; + received_frame_header.type = 0; + received_frame_header.length = 0; } void begin(int port); @@ -54,6 +56,9 @@ public: size_t writeFrame(const uint8_t src[], size_t len) override; size_t checkRecvFrame(uint8_t dest[]) override; + + bool hasReceivedFrameHeader(); + void resetReceivedFrameHeader(); }; #if WIFI_DEBUG_LOGGING && ARDUINO From 8708fa012ad9f64f1b7bc1fa93ef466378f4f496 Mon Sep 17 00:00:00 2001 From: liamcottle Date: Sun, 4 Jan 2026 17:43:25 +1300 Subject: [PATCH 3/3] simplify reading frame header --- src/helpers/esp32/SerialWifiInterface.cpp | 21 ++++----------------- 1 file changed, 4 insertions(+), 17 deletions(-) diff --git a/src/helpers/esp32/SerialWifiInterface.cpp b/src/helpers/esp32/SerialWifiInterface.cpp index de5cce78..462e3ecc 100644 --- a/src/helpers/esp32/SerialWifiInterface.cpp +++ b/src/helpers/esp32/SerialWifiInterface.cpp @@ -108,17 +108,8 @@ size_t SerialWifiInterface::checkRecvFrame(uint8_t dest[]) { if(client.available() >= frame_header_length){ // read frame header - uint8_t frame_header[3]; - client.readBytes(frame_header, frame_header_length); - - // parse frame header - uint8_t frame_type = frame_header[0]; - uint16_t frame_length; - memcpy(&frame_length, &frame_header[1], 2); - - // we have received a frame header - received_frame_header.type = frame_type; - received_frame_header.length = frame_length; + client.readBytes(&received_frame_header.type, 1); + client.readBytes((uint8_t*)&received_frame_header.length, 2); } @@ -161,12 +152,8 @@ size_t SerialWifiInterface::checkRecvFrame(uint8_t dest[]) { return 0; } - // read frame data - uint8_t frame_data[MAX_FRAME_SIZE]; - client.readBytes(frame_data, frame_length); - - // copy frame to provided buffer - memcpy(dest, frame_data, frame_length); + // read frame data to provided buffer + client.readBytes(dest, frame_length); // ready for next frame resetReceivedFrameHeader();